FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Shih, TH Povinelli, LA Liu, NS AF Shih, TH Povinelli, LA Liu, NS TI Application of generalized wall function for complex turbulent flows SO JOURNAL OF TURBULENCE LA English DT Article; Proceedings Paper CT 5th International Symposium on Engineering Turbulence Modelling and Measurements CY SEP 16-18, 2002 CL MALLORCA, SPAIN SP Spanish Minist Sci & Technol, Univ Zaragoza, Univ Karlsruhe, USAF, European Off Aerosp Res & Dev, CFX Germany, DaimlerChrysler AG, Elect France, NEC European Supercomp Syst AB This paper describes a generalized wall function for three-dimensional turbulent boundary layer flows. Since the formulation is valid for various pressure gradients including those associated with zero skin friction, it can be applied to wall bounded complex. ows with acceleration, deceleration and recirculation. This generalized wall function is extended to the whole surface layer ( or inner layer), covering the viscous sublayer, buffer layer and inertial sublayer; therefore, it is a unified wall function. This ' unified' feature is particularly useful for computational. fluid dynamics ( CFD) to deal with. ows with complex geometries, because it allows a. flexible grid resolution near the wall to provide accurate wall boundary conditions. This paper also describes a systematic procedure for implementing the wall function in a general CFD code. Finally, a few examples of complex turbulent. ows are presented to show the performance of the generalized wall function. C1 NASA, ICOMP, OAI, John H Glenn Res Ctr, Cleveland, OH 44142 USA. NASA, John H Glenn Res Ctr, Cleveland, OH 44135 USA. RP Shih, TH (reprint author), NASA, ICOMP, OAI, John H Glenn Res Ctr, Cleveland, OH 44142 USA. NR 9 TC 6 Z9 6 U1 1 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 1468-5248 J9 J TURBUL JI J. Turbul. PD APR 10 PY 2003 VL 4 AR 015 PG 16 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 665TF UT WOS:000182136800001 ER PT J AU Subramanyam, G Van Keuls, FW Miranda, FA Romanofsky, RR Warner, JD AF Subramanyam, G Van Keuls, FW Miranda, FA Romanofsky, RR Warner, JD TI Design and development of ferroelectric tunable HTS microstrip filters for Ku- and K-band applications SO MATERIALS CHEMISTRY AND PHYSICS LA English DT Article DE high temperature superconductor; Ku-band; K-band ID MICROWAVE AB In the past few years, our group has designed, fabricated and tested several ferroelectric tunable components, in collaboration with NASA Glenn Research Center. Among the components studied are microstrip tunable resonators, filters, diplexers, and couplers. Tunable filters with gold as well as YBCO high temperature superconductor (HTS) electrodes have been studied using the conductor/ferroelectric/dielectric two-layered microstrip configuration. Tunability is achieved through the non-linear dc electric field dependence of the relative dielectric constant of the ferroelectric thin film. Two pole ferroelectric tunable HTS filters using the YBCO/STO/LAO two-layered microstrip yielded low insertion loss as low as 1.5 dB, and large frequency tunability (similar to2.3 GHz) at 24 K, with a peak electric field of 80 W cm(-1) for electrical tuning. The critical design issues for realizing practical tunable filters will be addressed. These include design for (i) large tunability, (ii) low insertion loss, (iii) bandwidth considerations, and (iv) dc biasing for tuning the filters. HTS filters will be compared with their gold counter parts for their performance at Ku- and K-band frequencies. Also, our current work on BSTO based room temperature tunable filters will be presented. (C) 2002 Elsevier Science B.V. All rights reserved. C1 Univ Dayton, Dayton, OH 45469 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Subramanyam, G (reprint author), Univ Dayton, 300 Coll Pk, Dayton, OH 45469 USA. NR 8 TC 9 Z9 9 U1 0 U2 2 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0254-0584 J9 MATER CHEM PHYS JI Mater. Chem. Phys. PD APR 10 PY 2003 VL 79 IS 2-3 BP 147 EP 150 AR PII S0254-0584(02)00254-7 DI 10.1016/S0254-0584(02)00254-7 PG 4 WC Materials Science, Multidisciplinary SC Materials Science GA 648NJ UT WOS:000181157200011 ER PT J AU Rothschild, L AF Rothschild, L TI Pipe dreams SO NATURE LA English DT Editorial Material C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Rothschild, L (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 1 U2 2 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD APR 10 PY 2003 VL 422 IS 6932 BP 567 EP 567 DI 10.1038/422567a PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 665GN UT WOS:000182111400020 ER PT J AU D'Sa, EJ Miller, RL AF D'Sa, EJ Miller, RL TI Bio-optical properties in waters influenced by the Mississippi River during low flow conditions SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE bio-optical properties; Mississippi River; SeaWiFS; chlorophyll; CDOM ID ORGANIC-MATTER; OCEANIC WATERS; DIFFUSE-REFLECTANCE; ABSORPTION-SPECTRA; COASTAL WATERS; MEAN COSINE; CHLOROPHYLL; MODEL; PHYTOPLANKTON; IRRADIANCE AB Spatial and temporal patterns of bio-optical properties were studied in the Northern Gulf of Mexico during cruises in April and October of 2000, a year during which the discharge volume from the Mississippi River was unusually low. Highly variable surface Chl a concentrations (0.1 to 17 mg m(-3)) and colored dissolved organic matter (CDOM) absorption (0.07 to 1.1 m(-1) at 412 nm) were observed in the study region that generally decreased with increasing salinity waters, being highest nearshore and decreasing at offshore stations. The optical properties of absorption, scattering, and diffuse attenuation coefficients reflected these distributions with phytoplankton particles and CDOM contributing to most of the spatial, vertical, and seasonal variability. The diffuse attenuation coefficient K-d(lambda) and spectral remote sensing reflectance R-rs(lambda) were linear functions of absorption and backscattering coefficients a(lambda) and b(b)(lambda) through the downward average cosine mu(d) and the ratio of variables f/Q at the SeaWiFS wavebands for waters with widely varying bio-optical conditions. Although various R-rs(lambda) ratio combinations showed high correlation with surface Chl a concentrations and CDOM absorption at 412 nm, power law equations derived using the R-rs(490)/R-rs(555) and R-rs(510)/R-rs(555) ratios provided the best retrievals of Chl alpha concentrations and CDOM absorption from SeaWiFS reflectance data. (C) 2002 Elsevier Science Inc. All rights reserved. C1 NASA, GB Tech, Earth Sci Applicat Directorate, Stennis Space Ctr, MS 39529 USA. RP D'Sa, EJ (reprint author), NASA, GB Tech, Earth Sci Applicat Directorate, Stennis Space Ctr, MS 39529 USA. EM ejdsa@ssc.nasa.gov NR 38 TC 88 Z9 94 U1 4 U2 17 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD APR 10 PY 2003 VL 84 IS 4 BP 538 EP 549 AR PII S0034-4257(02)00163-3 DI 10.1016/S0034-4257(02)00163-3 PG 12 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 658RN UT WOS:000181734400006 ER PT J AU Wang, MG AF Wang, MG TI Correction of artifacts in the SeaWiFS atmospheric correction: removing discontinuity in the derived products SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE remote sensing; ocean color; atmospheric correction ID WATER-LEAVING RADIANCE; OCEAN-COLOR SENSORS; SPECTRAL REFLECTANCE; DIFFUSE TRANSMITTANCE; WHITECAPS; ALGORITHM AB It has been found that, at the certain solar and sensor-viewing geometry and for certain atmosphere conditions, discontinuity lines appear in the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) retrieved atmospheric and ocean color products. Such discontinuity lines, which do not happen very often, are apparently artifacts from the atmospheric correction scheme that uses the lookup tables to process SeaWiFS data. In this paper, a brief description of the SeaWiFS atmospheric correction algorithm, in particular, the technique that is used in retrieving the aerosol models and aerosol radiance contributions in the visible wavelengths, is provided. Results from some specific simulations that explain the causes of the discontinuity lines in the derived products are presented. We show that these discontinuities appearing in the derived SeaWiFS products are the result of the atmospheric correction due to aerosol model effects. To remove the discontinuities, a simple modification to the current atmospheric correction algorithm is proposed and tested with both simulated and real SeaWiFS data. The modification has been implemented in the SeaWiFS fourth data reprocessing in August 2002. (C) 2003 Elsevier Science Inc. All rights reserved. C1 Univ Maryland Baltimore Cty, NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Wang, MG (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 16 TC 2 Z9 3 U1 0 U2 1 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD APR 10 PY 2003 VL 84 IS 4 BP 603 EP 611 DI 10.1016/S0034-4257(02)00200-6 PG 9 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 658RN UT WOS:000181734400011 ER PT J AU Richmond, NC Hood, LL Halekas, JS Mitchell, DL Lin, RP Acuna, M Binder, AB AF Richmond, NC Hood, LL Halekas, JS Mitchell, DL Lin, RP Acuna, M Binder, AB TI Correlation of a strong lunar magnetic anomaly with a high-albedo region of the Descartes mountains SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID MOON; IMPACTS; SURFACE AB [1] Mapping and model simulations of Lunar Prospector magnetometer measurements show that the source of the strongest known magnetic anomaly on the lunar near side (42 nanoTeslas at 18.6 km altitude) coincides approximately with a high-albedo region of the Descartes mountains centered 60 km south-southeast of the Apollo 16 landing site. The Descartes mountains represent primary ejecta from one or more basin-forming events (Imbrium and/or Nectaris), supporting the hypothesis that basin ejecta materials emplaced >3.8 Gyr ago are the main sources of lunar magnetic anomalies. The higher albedo of the surface at this location is consistent with a significant role for solar wind ions in the optical maturation (or "space weathering'') of the lunar surface. C1 Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Lunar Res Inst, Tucson, AZ 85747 USA. RP Richmond, NC (reprint author), Univ Arizona, Lunar & Planetary Lab, 1629 E Univ Blvd, Tucson, AZ 85721 USA. OI Halekas, Jasper/0000-0001-5258-6128 NR 24 TC 28 Z9 32 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 9 PY 2003 VL 30 IS 7 AR 1395 DI 10.1029/2003GL016938 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 669JK UT WOS:000182348000006 ER PT J AU Campbell, JR Welton, EJ Spinhirne, JD Ji, Q Tsay, SC Piketh, SJ Barenbrug, M Holben, BN AF Campbell, JR Welton, EJ Spinhirne, JD Ji, Q Tsay, SC Piketh, SJ Barenbrug, M Holben, BN TI Micropulse lidar observations of tropospheric aerosols over northeastern South Africa during the ARREX and SAFARI 2000 dry season experiments SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE lidar; aerosols; biomass burning; Sun photometry; lidar ratio; SAFARI 2000 ID TO-BACKSCATTER RATIO; SIZE DISTRIBUTION; GREAT-PLAINS; DUST; TRANSPORT; ATLANTIC; SMOKE; AIR; CLIMATOLOGY; PARTICLES AB [1] During the Aerosol Recirculation and Rainfall Experiment (ARREX 1999) and Southern African Regional Science Initiative (SAFARI 2000) dry season experiments, a micropulse lidar (523 nm) instrument was operated at the Skukuza Airport in northeastern South Africa. The lidar was colocated with a diverse array of passive radiometric equipment. For SAFARI 2000, a daytime time series of layer mean aerosol optical properties, including layer mean extinction-to-backscatter ratios and vertical extinction cross-section profiles are derived from the synthesis of the lidar data and aerosol optical depths from available AERONET Sun photometer data. Combined with derived spectral Angstrom exponents, normalized broadband flux measurements, and calculated air mass back-trajectories, the temporal evolution of the surface aerosol layer optical properties is analyzed for climatological trends. For dense biomass smoke events the extinction-to-backscatter ratio is between 50 and 90 sr, and corresponding spectral Angstrom exponent values are between 1.50 and 2.00. Observations of an advecting smoke event during SAFARI 2000 are shown. The smoke was embedded within two distinct stratified thermodynamic layers causing the particulate mass to advect over the instrument array in an incoherent manner on the afternoon of 1 September 2000. Significant surface broadband flux forcing of over -50 W/m(2) was measured in this event. The evolution of the vertical aerosol extinction profile is profiled using the lidar data. Finally, observations of persistent elevated aerosol layers during ARREX 1999 are presented and discussed. Back-trajectory analyses combined with lidar and Sun photometer measurements indicate the likelihood for these aerosols being the result of long-range particulate transport from the southern and central South America. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. Univ Witwatersrand, Gauteng, South Africa. RP Campbell, JR (reprint author), NASA, Goddard Space Flight Ctr, Code 912, Greenbelt, MD 20771 USA. EM campbell@virl.gsfc.nasa.gov; Ellsworth.J.Welton@nasa.gov; jspin@virl.gsfc.nasa.gov; ji@climate.gsfc.nasa.gov; tsay@climate.gsfc.nasa.gov; stuart@crg.bpb.wits.ac.za; margie@crg.bpb.wits.ac.za; brent@aeronet.gsfc.nasa.gov RI Welton, Ellsworth/A-8362-2012; Campbell, James/C-4884-2012; Tsay, Si-Chee/J-1147-2014 OI Campbell, James/0000-0003-0251-4550; NR 53 TC 41 Z9 44 U1 1 U2 9 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 9 PY 2003 VL 108 IS D13 AR 8497 DI 10.1029/2002JD002563 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 669KQ UT WOS:000182350800001 ER PT J AU Neumann, GA Smith, DE Zuber, MT AF Neumann, GA Smith, DE Zuber, MT TI Two Mars years of clouds detected by the Mars Orbiter Laser Altimeter SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article DE Mars atmosphere; Mars climate; carbon dioxide snow; dust clouds; laser remote sensing ID RADIO OCCULTATION MEASUREMENTS; THERMAL EMISSION SPECTROMETER; MARTIAN POLAR CAPS; GLOBAL SURVEYOR; ICE CLOUDS; WATER; SNOW; TES; ATMOSPHERE; BEHAVIOR AB [1] The Mars Orbiter Laser Altimeter ( MOLA) instrument operated as an atmospheric lidar system as well as an altimeter, detecting absorptive clouds in northern latitudes shortly after orbit insertion in October 1997 and reflective clouds over the north polar cap at the start of the Science Phasing Orbits in March 1998. Global cloud measurements commenced with the primary mapping mission in March 1999, with nearly continuous coverage for 1.25 Mars years. MOLA tracked several dust storms, culminating with a major dust storm in June 2001. Reflective clouds, exhibiting distinctive patterns governed by insolation and the dynamics of the atmosphere, were detected at elevations up to 20 km above the surface, chiefly in the polar winter night. MOLA distinguishes cloud returns by pulse width and energy measurements. Unusually strong and brief reflections with minimal extinction suggest precipitation of CO2 snow under supercooled conditions. Weaker cloud reflections occurred at all latitudes. Some reflective daylight clouds at low latitudes suggested convective vortices or "dust devils.'' Ground fogs composed of dust and H2O ice formed at night along the seasonal frost line. Absorptive clouds, while not resolved altimetrically, tracked the advancing and receding edges of the seasonal polar caps. The absorptive and reflective clouds provide a seasonal profile of atmospheric activity spanning two Martian years. Winter reflective cloud activity declined to background levels earlier in the second year at both poles, suggesting interannual warming. C1 NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. RP Neumann, GA (reprint author), MIT, Dept Earth Atmospher & Planetary Sci, 54-518, Cambridge, MA 02139 USA. RI Neumann, Gregory/I-5591-2013 OI Neumann, Gregory/0000-0003-0644-9944 NR 55 TC 26 Z9 26 U1 2 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD APR 9 PY 2003 VL 108 IS E4 AR 5023 DI 10.1029/2002JE001849 PG 17 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 669LH UT WOS:000182352400001 ER PT J AU Lundgren, P Rosen, PA AF Lundgren, P Rosen, PA TI Source model for the 2001 flank eruption of Mt. Etna volcano SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID RADAR INTERFEROMETRY; MOUNT-ETNA; SAR INTERFEROMETRY; GROUND DEFORMATION; GPS DATA; TOPOGRAPHY; CATANIA; FAULTS AB [1] Using interferometric synthetic aperture radar (InSAR) we constrain the deformation sources for the July-August 2001 flank eruption of Mt. Etna volcano, Italy. InSAR data from ascending and descending passes of the ERS2 satellite reveal a pattern of deformation that cannot be explained by a dike intrusion alone. In addition to a vertical dike beneath the south rift zone, the spatially large (10 km scale, 15-20 cm in range) negative range displacement lobes across the western (descending data) and eastern (ascending data) flanks require a nearly symmetric set of shallowly dipping normal faults to each side of the central dike. Complexity in the observed InSAR surface displacements constrains an additional dike intrusion beneath its NE flank. Long-term deformation of Etna's eastern and southern flanks is well established through field and InSAR observations. Therefore, the relative symmetry of motion beneath both the western and eastern flanks during the 2001 eruption is surprising. Our model of symmetric flank motion suggests that on the short time scales of a large dike intrusion volcanoes can deform differently from their long-term deformation. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lundgren, P (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 20 TC 24 Z9 24 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 8 PY 2003 VL 30 IS 7 AR 1388 DI 10.1029/2002GL016774 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 669JG UT WOS:000182347700007 ER PT J AU Miller, CE Cohen, EA AF Miller, CE Cohen, EA TI The rotational spectrum of iodine dioxide, OIO SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID CHLORINE DIOXIDE; MICROWAVE-SPECTRUM; SPECTROSCOPY; RESONANCE; OXIDES; STATES; OCLO; OBRO; BRO; IO AB The rotational spectrum of the OIO radical has been observed for the first time. Spectra of both the ground and first two excited bending vibrational states have been analyzed. Rotational, centrifugal distortion, fine, and hyperfine constants have been derived. These constants have been used to determine the molecular structure, harmonic force field, and electron distribution. The OIO molecular parameters are compared with those of OClO and OBrO. (C) 2003 American Institute of Physics. C1 Haverford Coll, Dept Chem, Haverford, PA 19041 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Miller, CE (reprint author), Haverford Coll, Dept Chem, Haverford, PA 19041 USA. NR 49 TC 9 Z9 9 U1 1 U2 9 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD APR 8 PY 2003 VL 118 IS 14 BP 6309 EP 6317 DI 10.1063/1.1540107 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 660LP UT WOS:000181834900024 ER PT J AU Djikaev, YS Tabazadeh, A Reiss, H AF Djikaev, YS Tabazadeh, A Reiss, H TI Thermodynamics of crystal nucleation in multicomponent droplets: Adsorption, dissociation, and surface-stimulated nucleation SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID NONISOTHERMAL BINARY NUCLEATION; THERMAL RELAXATION; KINETIC-THEORY; SULFURIC-ACID; CLUSTERS; SIMULATIONS; STAGE; SEF6 AB We extend our previous work on crystallization of unary liquids [Djikaev , J. Phys. Chem. A 106, 10247 (2002)] to multicomponent systems and develop the Gibbsian thermodynamics of the crystallization of multicomponent liquid solutions (bulk as well as droplets). Our treatment takes into account the possibility of formation of a solid phase from a nonstoichiometric liquid solution (noncongruent solidification). Using the capillarity approximation and taking into account both dissociation and surface adsorption effects, we derive the reversible work of formation of a crystal nucleus in homogeneous and pseudoheterogeneous modes (the density difference between crystal and liquid phases is also taken into account). In the former mode, the nucleus forms homogeneously within the (supercooled) bulk liquid solution, while in the latter mode, it forms "pseudoheterogeneously" at the liquid-vapor interface. Comparison of the works of formation in the two modes provides an inequality which must hold in order for pseudoheterogeneous crystal nucleation to be thermodynamically favored over the homogeneous process. As for unary systems, this inequality is identical to the condition of partial wetting of at least one crystal facet by its melt, i.e., the effects of adsorption and dissociation do not explicitly alter the thermodynamic condition for surface-stimulated crystallization in multicomponent systems. These effects do play an important role in determining the crystal nucleation mode, because they contribute to the liquid-vapor and liquid-solid surface tensions that enter the condition of partial wetting. The influence of these effects on the freezing behavior of droplets is expected to depend on the droplet size. (C) 2003 American Institute of Physics. C1 NASA, NRC Associateship, Ames Res Ctr, Moffett Field, CA 94035 USA. NASA, Ames Res Ctr, Div Earth Sci, Moffett Field, CA 94035 USA. Univ Calif Los Angeles, Dept Chem & Biochem, Los Angeles, CA 90095 USA. RP Djikaev, YS (reprint author), NASA, NRC Associateship, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 26 TC 22 Z9 22 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 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD APR 8 PY 2003 VL 118 IS 14 BP 6572 EP 6581 DI 10.1063/1.1559034 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 660LP UT WOS:000181834900052 ER PT J AU Petrov, L Ma, CP AF Petrov, L Ma, CP TI Study of harmonic site position variations determined by very long baseline interferometry SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article DE ocean; tide; loading; VLBI ID OCEAN-TIDE; VLBI DATA; STATION DISPLACEMENTS; RADIO INTERFEROMETRY; LOADING CORRECTIONS; EARTH ROTATION; LOVE; PARAMETERS; SYSTEM; NUMBERS AB [1] Position variations of 40 very long baseline interferometry (VLBI) stations at 32 tidal frequencies were obtained from analysis of 3 million measurements of group delays from 1980 to 2002. Residual displacements after the removal of the effect of solid Earth tides were studied. The purpose of this study is to investigate a harmonic signal at any frequency where it is expected and to assess quantitatively whether the models of vertical and horizontal site position variations agree with the observations. It was found that the estimates of station displacements are generally in good agreement with the ocean loading computed on the basis of ocean tide models for the main diurnal and semidiurnal tides. Moreover, VLBI results allow us to discriminate between different ocean tide models. However, discrepancies between VLBI results and all models of ocean loading for K-1, K-2, and S-2 tides exceed both the errors of the VLBI estimates and the errors of ocean loading displacements based on the reported formal uncertainties of ocean tide models. It was found that there is a significant nontidal signal at diurnal and annual frequencies. Applying a model of hydrological loading reduces the variance of the residual vertical displacements at the annual frequency by 30%. Using an empirical model of harmonic site position variations in VLBI processing provides a better fit and improves the baseline length repeatability. C1 NASA, NVI Inc, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Petrov, L (reprint author), NASA, NVI Inc, Goddard Space Flight Ctr, Code 926, Greenbelt, MD 20771 USA. EM pet@leo.gsfc.nasa.gov; cma@virgo.gsfc.nasa.gov RI Ma, Chopo/D-4751-2012 NR 56 TC 30 Z9 32 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 8 PY 2003 VL 108 IS B4 AR 2190 DI 10.1029/2002JB001801 PG 16 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 673NR UT WOS:000182587500002 ER PT J AU Goldstein, J Spasojevic, M Reiff, PH Sandel, BR Forrester, WT Gallagher, DL Reinisch, BW AF Goldstein, J Spasojevic, M Reiff, PH Sandel, BR Forrester, WT Gallagher, DL Reinisch, BW TI Identifying the plasmapause in IMAGE EUV data using IMAGE RPI in situ steep density gradients SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE plasmasphere; plasmapause; inner magnetosphere; remote sensing; imaging ID ION COMPOSITION MEASUREMENTS; EXTREME-ULTRAVIOLET IMAGER; OUTER PLASMASPHERE; SATELLITE-OBSERVATIONS; EARTHS MAGNETOSPHERE; MAGNETIC-FIELD; SPACECRAFT; DYNAMICS; RECOVERY; MISSION AB [1] Remote sensing of the entire plasmasphere is routinely accomplished by the Extreme Ultraviolet (EUV) imager on the IMAGE satellite. EUV observes the helium distribution in the plasmasphere by detecting resonantly scattered solar 30.4-nm ultraviolet radiation. In EUV images the plasmapause is assumed to be the "He+ edge,'' i.e., the outermost sharp edge where the brightness of 30.4-nm He+ emissions drops abruptly. This assumption is verified by comparing the L-shell of steep electron density gradients, extracted from passive mode dynamic spectrograms recorded by the IMAGE Radio Plasma Imager (RPI) when the satellite is at low magnetic latitude, with the L-shell of EUV He+ edges obtained when the satellite is outside the plasmasphere near apogee. A statistical study of all inbound ( dawn sector) plasmapause crossings was performed for the month of June 2001. When the plasmapause location observed by RPI is compared to the location of the He+ edge extracted from the closest-in-time EUV image, a correlation coefficient of 0.83 is obtained. When the EUV He+ edge location is taken as the average of two EUV measurements ( one before and one after the RPI measurement), the correlation coefficient increases to 0.87. The high degree of correlation justifies the assumption that the He+ edge coincides with the plasmapause. For eighteen cases in which the plasmasphere has no sharp outer boundary the intensity of the uncalibrated EUV images is compared with the electron number density extracted from the RPI data, and the lower sensitivity threshold of the EUV instrument is estimated to be 40 +/- 10 electrons cm(-3). C1 Rice Univ, Dept Phys & Astron, Houston, TX 77005 USA. Stanford Univ, STAR Lab, Stanford, CA 94305 USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. NASA, MSFC, NSSTC, Huntsville, AL 35805 USA. Univ Massachusetts, Ctr Atmospher Sci, Lowell, MA 01854 USA. RP Goldstein, J (reprint author), Rice Univ, Dept Phys & Astron, Houston, TX 77005 USA. RI Reiff, Patricia/D-2564-2014 OI Reiff, Patricia/0000-0002-8043-5682 NR 44 TC 91 Z9 91 U1 1 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD APR 8 PY 2003 VL 108 IS A4 AR 1147 DI 10.1029/2002JA009475 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 669MR UT WOS:000182355500001 ER PT J AU Adessi, C Anantram, MP AF Adessi, C Anantram, MP TI Influence of counter-ion-induced disorder in DNA conduction SO APPLIED PHYSICS LETTERS LA English DT Article ID ELECTRICAL-CONDUCTION; MOLECULES; TRANSPORT AB Disorder along a DNA strand due to nonuniformity associated with the counter ion type and location, and in rise and twist are investigated using density functional theory. We then model the conductance through a poly(G) DNA strand by including the influence of disorder. We show that the conductance drops by a few orders of magnitude between typical lengths of 10 and 100 nm. Such a decrease occurs with on-site potential disorder that is larger than 100 meV. (C) 2003 American Institute of Physics. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Adessi, C (reprint author), NASA, Ames Res Ctr, Mail Stop N229-1, Moffett Field, CA 94035 USA. NR 18 TC 30 Z9 31 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 7 PY 2003 VL 82 IS 14 BP 2353 EP 2355 DI 10.1063/1.1563811 PG 3 WC Physics, Applied SC Physics GA 663RH UT WOS:000182018800053 ER PT J AU Yoder, KB Elmustafa, AA Lin, JC Hoffman, RA Stone, DS AF Yoder, KB Elmustafa, AA Lin, JC Hoffman, RA Stone, DS TI Activation analysis of deformation in evaporated molybdenum thin films SO JOURNAL OF PHYSICS D-APPLIED PHYSICS LA English DT Article ID MECHANICAL-PROPERTIES; NANOCRYSTALLINE MATERIALS; CONTACT STIFFNESS; X-RAY; NANOINDENTATION; HARDNESS; NIOBIUM; STRENGTH; NICKEL; ALLOYS AB Using nanoindentation, we investigate hardening mechanisms in steered arc (SA) evaporated and electron-beam (EB) evaporated molybdenum thin films. Both films have columnar grains, with the column diameters ranging between 22 and 170 nm in the SA films and 30 and 40 nm in the EB films. The Hall-Petch relation is extended out to hardness values between 6 and 12 GPa. Analysis of nanoindentation creep data (creep, load relaxation, and rate change) reveals that, in the SA films, thermally activated glide is rate controlling, and that grain size has little effect on the underlying rate processes even down to 22 nm. There is evidence based on x-ray diffraction (and supported by the literature) that the EB films contain high densities of interstitial loops resulting from argon ion bombardment during deposition. The analysed creep data indicate that these loops affect the thermal activation of dislocations. C1 Univ Wisconsin, Mat Sci Program, Madison, WI USA. NASA, Langley Res Ctr, ConITS, Hampton, VA 23665 USA. Alcoa Tech Ctr, Alcoa Ctr, PA USA. Northwestern Univ, Mat Testing Lab, Evanston, IL 60208 USA. RP Stone, DS (reprint author), Univ Wisconsin, Dept Mat Sci & Engn, 1509 Univ Ave, Madison, WI 53706 USA. RI Stone, Donald/A-7496-2016 NR 54 TC 16 Z9 16 U1 0 U2 5 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0022-3727 J9 J PHYS D APPL PHYS JI J. Phys. D-Appl. Phys. PD APR 7 PY 2003 VL 36 IS 7 BP 884 EP 895 AR PII S0022-3727(03)55027-6 DI 10.1088/0022-3727/36/7/318 PG 12 WC Physics, Applied SC Physics GA 673NE UT WOS:000182586400019 ER PT J AU Ackerman, AS Toon, OB Stevens, DE Coakley, JA AF Ackerman, AS Toon, OB Stevens, DE Coakley, JA TI Enhancement of cloud cover and suppression of nocturnal drizzle in stratocumulus polluted by haze SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SHIP TRACKS; BOUNDARY-LAYER; SIMULATIONS; MICROPHYSICS; AEROSOLS; DYNAMICS; SHALLOW; ALBEDO; MODEL AB [1] Recent satellite observations indicate a significant decrease of cloud water in ship tracks, in contrast to an ensemble of in situ ship-track measurements showing no average change in cloud water relative to the surrounding clouds, and contrary to the expectation of cloud water increasing in polluted clouds. We find through large-eddy simulations of stratocumulus that the trend in the satellite data is likely an artifact of sampling only overcast clouds. The simulations instead show cloud cover increasing with droplet concentrations. The simulations also show that increases in cloud water from suppressing drizzle by increasing droplet concentrations are favored at night or at extremely low droplet concentrations. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Colorado, Boulder, CO 80309 USA. Lawrence Livermore Natl Lab, Livermore, CA 94552 USA. Oregon State Univ, Corvallis, OR 97331 USA. RP Ackerman, AS (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RI Ackerman, Andrew/D-4433-2012 OI Ackerman, Andrew/0000-0003-0254-6253 NR 20 TC 41 Z9 41 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 5 PY 2003 VL 30 IS 7 AR 1381 DI 10.1029/2002GL016634 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 667NK UT WOS:000182238100005 ER PT J AU Kuang, ZM Toon, GC Wennberg, PO Yung, YL AF Kuang, ZM Toon, GC Wennberg, PO Yung, YL TI Measured HDO/H2O ratios across the tropical tropopause SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID STRATOSPHERIC WATER-VAPOR; ISOTOPIC COMPOSITION; AIRCRAFT MEASUREMENTS; TROPOSPHERE EXCHANGE; LINE POSITIONS; TRANSPORT; DEHYDRATION; CLIMATE; DEUTERIUM; STRENGTHS AB [1] We present the first simultaneous measurements of HDO and H2O in the tropical upper troposphere (UT) and lower stratosphere (LS) as derived from infrared solar absorption spectra acquired by the Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment. We find, surprisingly, that the observed HDO/H2O ratio does not decrease with altitude in this region despite a factor of 4-5 decrease in the water vapor mixing ratio. This observation is inconsistent with the view that dehydration in the tropical UT/LS is by gradual processes, and suggests a major role by convective processes. C1 CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Kuang, ZM (reprint author), Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. RI Wennberg, Paul/A-5460-2012 NR 26 TC 61 Z9 61 U1 1 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 4 PY 2003 VL 30 IS 7 AR 1372 DI 10.1029/2003GL017023 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 667NH UT WOS:000182237900006 ER PT J AU Vennerstrom, S Olsen, N Purucker, M Acuna, MH Cain, JC AF Vennerstrom, S Olsen, N Purucker, M Acuna, MH Cain, JC TI The magnetic field in the pile-up region at Mars, and its variation with the solar wind SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID VENUS AB [1] The magnetic measurements from the Mars Global Surveyor satellite are used to study the magnetic field on the Martian dayside, and its variation with the solar wind. Because of the lack of solar wind measurements near Mars, solar wind measurements near Earth during a period centered on a Mars-Earth conjunction are used. Concurrent variations at Mars and Earth related to the interplanetary sector-structure and dynamic pressure variations are demonstrated. The study is confined to the northern hemisphere of Mars in regions where the crustal anomalies are weak. Here we find a close association between the solar wind dynamic pressure and the magnetic pressure in the pile-up region, and also a strong asymmetry with the Interplanetary magnetic field (IMF) By-component, probably related to solar wind pick-up of planetary ions. C1 Danish Space Res Inst, Ctr Planetary Res, DK-2100 Copenhagen O, Denmark. NASA, Goddard Space Flight Ctr, Geodynam Branch, Raytheon ITSS, Greenbelt, MD 20771 USA. Florida State Univ, Inst Geophys Fluid Dynam, Tallahassee, FL 32306 USA. RP Danish Space Res Inst, Ctr Planetary Res, Juliane Maries Vej 30, DK-2100 Copenhagen O, Denmark. EM sv@dsri.dk RI Olsen, Nils/H-1822-2011 OI Olsen, Nils/0000-0003-1132-6113 NR 11 TC 45 Z9 45 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 4 PY 2003 VL 30 IS 7 AR 1369 DI 10.1029/2003GL016883 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 667NH UT WOS:000182237900005 ER PT J AU Messenger, S Keller, LP Stadermann, FJ Walker, RM Zinner, E AF Messenger, S Keller, LP Stadermann, FJ Walker, RM Zinner, E TI Samples of stars beyond the solar system: Silicate grains in interplanetary dust SO SCIENCE LA English DT Article ID GIANT BRANCH STARS; STELLAR NUCLEOSYNTHESIS; ISOTOPIC COMPOSITION; OXYGEN ISOTOPES; OXIDE GRAIN; PRESOLAR; METEORITES; PARTICLES; CORUNDUM; IDENTIFICATION AB We have identified six circumstellar silicate grains within interplanetary dust particles (IDPs). Their extrasolar origins are demonstrated by their extremely anomalous oxygen isotopic compositions. Three (17)O-rich grains appear to originate from red giant or asymptotic giant branch stars. One (16)O-rich grain may be from a metal-poor star. Two (16)O-poor grains have unknown stellar sources. One of the grains is forsterite, and two are amorphous silicate "GEMS" (glass with embedded metal and sulfides), which is consistent with astronomical identifications of crystalline and amorphous silicates in the outflows of evolved stars. These observations suggest cometary origins of these IDPs and underscore the perplexing absence of silicates among circumstellar dust grains from meteorites. C1 Washington Univ, Space Sci Lab, St Louis, MO 63130 USA. Washington Univ, Dept Phys, St Louis, MO 63130 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Messenger, S (reprint author), Washington Univ, Space Sci Lab, St Louis, MO 63130 USA. NR 34 TC 255 Z9 260 U1 1 U2 22 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 4 PY 2003 VL 300 IS 5616 BP 105 EP 108 DI 10.1126/science.1080576 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 663CP UT WOS:000181988900041 PM 12610229 ER PT J AU Chandrasekhar, P Zay, BJ McQueeney, T Scara, A Ross, D Birur, GC Haapanen, S Kauder, L Swanson, T Douglas, D AF Chandrasekhar, P Zay, BJ McQueeney, T Scara, A Ross, D Birur, GC Haapanen, S Kauder, L Swanson, T Douglas, D TI Conducting Polymer (CP) infrared electrochromics in spacecraft thermal control and military applications SO SYNTHETIC METALS LA English DT Article; Proceedings Paper CT International Conference on Science and Technology of Synthetic Metals (ICSM 2002) CY JUN 29-JUL 05, 2002 CL SHANGHAI, PEOPLES R CHINA DE conducting; polymer; infrared; electrochromic; spacecraft; military AB The implementation of advanced CP-based far-IR electrochromics in an actual spacecraft (NASA's ST5 mission to be launched 2003) and defense (IR-homing missile countermeasure) application is described. For spacecraft thermal control, the modification of fundamental CP properties and innovative device design required to pass the rigors of space (e.g. 10(-7) Torr, +/- 90 degreesC, high radiation, p/e and atomic-O fluxes, ESD/EMP) while meeting the minimum performance (Emittance variation of 0.42) are described. Space qualification test results presented show the surprising versatility of CPs. For the military application, detailed data, in the form of IR camera pictures, are presented. These encompass a variety of environments (e.g. foliage, sand, water, sky, snow) and modes (e.g. total darkness, heat from behind, front, cooling from behind). These show excellent IR camouflage performance under all conditions. C1 Ashwin Ushas Corp Inc, Lakewood, NJ 08701 USA. Jet Prop Lab, Pasadena, CA 91109 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Chandrasekhar, P (reprint author), Ashwin Ushas Corp Inc, 500 James St,Unit 7, Lakewood, NJ 08701 USA. NR 6 TC 25 Z9 32 U1 4 U2 9 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD APR 4 PY 2003 VL 135 IS 1-3 SI SI BP 23 EP 24 DI 10.1016/S0379-6779(02)00682-3 PN 1 PG 2 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA 672QW UT WOS:000182533700011 ER PT J AU Wenig, M Spichtinger, N Stohl, A Held, G Beirle, S Wagner, T Jahne, B Platt, U AF Wenig, M Spichtinger, N Stohl, A Held, G Beirle, S Wagner, T Jahne, B Platt, U TI Intercontinental transport of nitrogen oxide pollution plumes SO ATMOSPHERIC CHEMISTRY AND PHYSICS LA English DT Article ID SOUTHERN AFRICA; GLOBAL DISTRIBUTION; TROPOSPHERIC OZONE; GOME MEASUREMENTS; NOX; EMISSIONS; RECIRCULATION; TROPOPAUSE; ATMOSPHERE; SULFUR AB We describe the first satellite observation of intercontinental transport of nitrogen oxides emitted by power plants, verified by simulations with a particle tracer model. The analysis of such episodes shows that anthropogenic NOx plumes may influence the atmospheric chemistry thousands of kilometers away from its origin, as well as the ocean they traverse due to nitrogen fertilization. This kind of monitoring became possible by applying an improved algorithm to extract the tropospheric fraction of NO2 from the spectral data coming from the GOME instrument. As an example we show the observation of NO2 in the time period 4-14 May, 1998, from the South African Plateau to Australia which was possible due to favourable weather conditions during that time period which availed the satellite measurement. This episode was also simulated with the Lagrangian particle dispersion model FLEXPART which uses NOx emissions taken from an inventory for industrial emissions in South Africa and is driven with analyses from the European Centre for Medium-RangeWeather Forecasts. Additionally lightning emissions were taken into account by utilizing Lightning Imaging Sensor data. Lightning was found to contribute probably not more than 25% of the resulting concentrations. Both, the measured and simulated emission plume show matching patterns while traversing the Indian Ocean to Australia and show great resemblance to the aerosol and CO2 transport observed by Piketh et al. (2000). C1 Univ Heidelberg, Inst Umweltphys, D-6900 Heidelberg, Germany. Interdisziplinares Zentrum Wissenschaftliches Rec, Heidelberg, Germany. TUM, Lehrstuhl Bioklimatol & Immiss Forsch, Freising Weihenstephan, Germany. Univ Estadual Paulista, Inst Pesquisas Meteorol, Sao Paulo, Brazil. RP Wenig, M (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Stohl, Andreas/A-7535-2008; Wenig, Mark/K-7279-2012; Held, Gerhard/G-1492-2013 OI Stohl, Andreas/0000-0002-2524-5755; NR 41 TC 58 Z9 61 U1 0 U2 8 PU EUROPEAN GEOPHYSICAL SOC PI KATLENBURG-LINDAU PA MAX-PLANCK-STR 13, 37191 KATLENBURG-LINDAU, GERMANY SN 1680-7324 J9 ATMOS CHEM PHYS JI Atmos. Chem. Phys. PD APR 3 PY 2003 VL 3 BP 387 EP 393 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 664XT UT WOS:000182090500003 ER PT J AU Lu, CH Yue, GK Joseph, ED Mohnen, VA AF Lu, CH Yue, GK Joseph, ED Mohnen, VA TI Retrieval analysis of aerosol integral properties from simulated extinction at SAGE II and HALOE wavelengths SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE aerosol retrieval; SAGE II ID INFRARED OPTICAL-CONSTANTS; STRATOSPHERIC AEROSOL; OCCULTATION EXPERIMENT; SIZE DISTRIBUTIONS; SULFURIC-ACID; INVERSION ALGORITHM; PINATUBO AEROSOL; OZONE DEPLETION; EL-CHICHON; VALIDATION AB [1] Aerosol integral properties inferred from simulated multispectral extinction data at Stratospheric Aerosol and Gas Experiment (SAGE) II and the Halogen Occultation Experiment (HALOE) wavelengths using two different retrieval methods are analyzed and compared. The discrepancy in aerosol integral properties that results from using different retrieval techniques is analyzed, and the differences caused by sampling the same aerosol population at different wavelengths with the same retrieval technique are evaluated. We found that a better agreement was achieved when different methods were applied to the same data set as compared to a case where the same method is applied to data recorded by two different sensors. Our results demonstrate that when comparing aerosol properties derived from different instruments, the particle size information contents from optical instruments have to be taken into consideration together with the propagation of measurement errors and the systematic errors arising from the retrieval methods. C1 NOAA, NWS, NCEP, Environm Modeling Ctr, Camp Springs, MD 20746 USA. NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23681 USA. Howard Univ, Dept Phys & Astron, Washington, DC 20059 USA. SUNY Albany, Atmospher Sci Res Ctr, Albany, NY 12203 USA. RP Lu, CH (reprint author), RS Informat Syst, Mclean, VA 22102 USA. EM Sarah.Lu@noaa.gov; g.k.yue@larc.nasa.gov; ejoseph@howard.edu; vam@atmos.albany.edu NR 41 TC 2 Z9 2 U1 1 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 3 PY 2003 VL 108 IS D7 AR 4202 DI 10.1029/2002JD002453 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 667NP UT WOS:000182238800002 ER PT J AU McGill, MJ Hlavka, DL Hart, WD Welton, EJ Campbell, JR AF McGill, MJ Hlavka, DL Hart, WD Welton, EJ Campbell, JR TI Airborne lidar measurements of aerosol optical properties during SAFARI-2000 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE lidar; aerosols; SAFARI; optical depth; aerosol extinction ID TROPOSPHERIC AEROSOL; SAVANNA FIRES; RATIO AB [1] The Cloud Physics Lidar (CPL) operated onboard the NASA ER-2 high-altitude aircraft during the Southern African Regional Science Initiative (SAFARI)-2000 field campaign. The CPL provided high spatial resolution estimates of aerosol optical properties at both 1064 and 532 nm. We present here results of planetary boundary layer (PBL) aerosol optical depth analysis and profiles of aerosol extinction. Variation of optical depth and extinction are examined as a function of regional location. The wide-scale aerosol mapping obtained by the CPL is a unique data set that will aid in future studies of aerosol transport. Comparisons between the airborne CPL and ground-based Micro-Pulse Lidar Network (MPL-Net) sites are shown to have good agreement. C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Goddard Earth Sci & Technol Ctr, Greenbelt, MD 20771 USA. RP McGill, MJ (reprint author), NASA, Goddard Space Flight Ctr, Atmospheres Lab, Code 912, Greenbelt, MD 20771 USA. EM mcgill@virl.gsfc.nasa.gov; billhart@virl.gsfc.nasa.gov; sgdlh@virl.gsfc.nasa.gov; welton@virl.gsfc.nasa.gov; campbell@virl.gsfc.nasa.gov RI Welton, Ellsworth/A-8362-2012; Campbell, James/C-4884-2012; McGill, Matthew/D-8176-2012; OI Campbell, James/0000-0003-0251-4550; Hlavka, Dennis/0000-0002-2976-7243 NR 21 TC 44 Z9 44 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 3 PY 2003 VL 108 IS D13 AR 8493 DI 10.1029/2002JD002371 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 667NW UT WOS:000182239600005 ER PT J AU Schmid, B Redemann, J Russell, PB Hobbs, PV Hlavka, DL McGill, MJ Holben, BN Welton, EJ Campbell, JR Torres, O Kahn, RA Diner, DJ Helmlinger, MC Chu, DA Robles-Gonzalez, C de Leeuw, G AF Schmid, B Redemann, J Russell, PB Hobbs, PV Hlavka, DL McGill, MJ Holben, BN Welton, EJ Campbell, JR Torres, O Kahn, RA Diner, DJ Helmlinger, MC Chu, DA Robles-Gonzalez, C de Leeuw, G TI Coordinated airborne, spaceborne, and ground-based measurements of massive thick aerosol layers during the dry season in southern Africa SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE aerosol; Sun photometer; biomass burning; optical depth; satellite ID COLUMNAR WATER-VAPOR; OPTICAL DEPTH; IMAGING SPECTRORADIOMETER; INSTRUMENT DESCRIPTION; TROPOSPHERIC AEROSOL; IN-SITU; RETRIEVAL; ABSORPTION; AERONET; SOLAR AB [1] During the dry season airborne campaign of the Southern African Regional Science Initiative (SAFARI 2000), coordinated observations were made of massive thick aerosol layers. These layers were often dominated by aerosols from biomass burning. We report on airborne Sun photometer measurements of aerosol optical depth (lambda = 0.354-1.557 mum), columnar water vapor, and vertical profiles of aerosol extinction and water vapor density that were obtained aboard the University of Washington's Convair-580 research aircraft. We compare these with ground-based AERONET Sun/sky radiometer results, with ground based lidar data (MPL-Net), and with measurements from a downward pointing lidar aboard the high-flying NASA ER-2 aircraft. Finally, we show comparisons between aerosol optical depths from the Sun photometer and those retrieved over land and over water using four spaceborne sensors (TOMS, MODIS, MISR, and ATSR-2). C1 Bay Area Environm Res Inst, Sonoma, CA 95476 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Goddard Earth Sci & Technol Ctr, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, NASA, Goddard Space Flight Ctr, Joint Ctr Earth Syst, Greenbelt, MD 20771 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. TNO, Phys & Elect Lab, NL-2509 JG The Hague, Netherlands. RP Bay Area Environm Res Inst, 560 3rd St W, Sonoma, CA 95476 USA. EM bschmid@mail.arc.nasa.gov; fredemann@mail.arc.nasa.gov; prussell@mail.arc.nasa.gov; phobbs@atmos.washington.edu; sgdlh@virl.gsfc.nasa.gov; mcgill@virl.gsfc.nasa.gov; brent@aeronet.gsfc.nasa.gov; welton@virl.gsfc.nasa.gov; campbell@virl.gsfc.nasa.gov; torres@tparty.gsfc.nasa.gov; Ralph.A.Kahn@jpl.nasa.gov; David.J.Diner@jpl.nasa.gov; Mark.C.Helmlinger@jpl.nasa.gov; chu@climate.gsfc.nasa.gov; Robles-Gonzalez@fel.tno.nl; deleeuw@fel.tno.nl RI Welton, Ellsworth/A-8362-2012; Campbell, James/C-4884-2012; McGill, Matthew/D-8176-2012; Kahn, Ralph/D-5371-2012; Torres, Omar/G-4929-2013 OI Campbell, James/0000-0003-0251-4550; Kahn, Ralph/0000-0002-5234-6359; NR 53 TC 67 Z9 68 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 3 PY 2003 VL 108 IS D13 AR 8496 DI 10.1029/2002JD002297 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 667NW UT WOS:000182239600002 ER PT J AU Wilson, GR Moore, TE Collier, M AF Wilson, GR Moore, TE Collier, M TI Low-energy neutral atoms observed near the Earth SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE neutral atoms; auroral zone; ion outflow ID LESS-THAN-OR-EQUAL-TO-10 KEV ENERGIES; ION OUTFLOW; SOLAR-CYCLE; MAGNETOSPHERE; ACCELERATION; MECHANISMS; ALTITUDES; IMAGES AB [1] During the summer of 2000 the LENA instrument on the IMAGE spacecraft collected a unique data set of low-energy, neutral atom emissions. The data suggests an ever-present flux of low energy (< 50 eV) oxygen neutrals in the near-Earth environment, typically below 4000 km altitude. Because of two different patterns in the images made during a number of spacecraft perigee passes we infer at least two main sources for these particles. One ( possibly from the auroral zone) produces a high degree of variability from one image to the next and creates more energetic particles, and another ( possibly part of the hot oxygen geocorona) gives less variability within a sequence of images and lower energy particles. Overall, the measured neutral fluxes increase with increasing magnetic activity. During Southern Hemisphere winter the total neutral flux rates vary diurnally with peak intensity near 0740 UT and a minimum near 1940 UT. Near perigee, neutral fluxes are often seen coming from a broad range of directions so that a localized source, such as the auroral zone, alone cannot produce it. Processes affecting low-energy oxygen neutrals, such as gravitational deflection or spacecraft ram deflection, cannot broaden a localized source enough to match the data. C1 Mission Res Corp, Nashua, NH USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Wilson, GR (reprint author), Mission Res Corp, Nashua, NH USA. RI Moore, Thomas/D-4675-2012; Collier, Michael/I-4864-2013 OI Moore, Thomas/0000-0002-3150-1137; Collier, Michael/0000-0001-9658-6605 NR 20 TC 7 Z9 7 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD APR 3 PY 2003 VL 108 IS A4 AR 1142 DI 10.1029/2002JA009643 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 667QH UT WOS:000182243900005 ER PT J AU Fernandez, JM Sayir, A Farmer, SC AF Fernandez, JM Sayir, A Farmer, SC TI High temperature creep deformation of directionally solidified Al2O3/Er3Al5O12 SO ACTA MATERIALIA LA English DT Article DE creep; high temperature; eutectic; strain recovery ID OXYGEN TRACER DIFFUSION; YTTRIUM-ALUMINUM-GARNET; MECHANICAL-PROPERTIES; MICROSTRUCTURE; STRENGTH; YAG AB The microstructure of directionally solidified Al2O3/Er3Al5O12 (19.5 mol% Er2O3) is analyzed and high temperature creep deformation studied using fibers in tension between 1400degrees C and 1550degrees C. The directionally solidified Al2O3/Er3Al5O12 system is an in situ composite and has a fine eutectic- microstructure with sub-micron phase spacing. The microstructure is elongated in the direction of growth. Transmission electron microscopy observations revealed well-bonded interfaces and scatter within the crystallographic alignment of the constituent phases. The creep resistance of the system was very high, comparable to c-axis sapphire, and failure initiated at the lamella interfaces. The influence of the different elastic and plastic behaviors of the eutectic components on creep is examined. A critical discussion on the origin of the high stress dependence of the creep rate, the existence of steady state creep, and the relevant microscopic deformation mechanisms is presented. (C) 2003 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Case Western Reserve Univ, Cleveland, OH 44135 USA. Univ Sevilla, Dept Fis Mat Condensada, Seville, Spain. RP Fernandez, JM (reprint author), NASA, Glenn Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. EM martinez@us.es RI MARTINEZ FERNANDEZ, JULIAN/K-1826-2012 OI MARTINEZ FERNANDEZ, JULIAN/0000-0002-1199-6638 NR 30 TC 23 Z9 23 U1 0 U2 12 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD APR 2 PY 2003 VL 51 IS 6 BP 1705 EP 1720 DI 10.1016/S1359-6454(02)00571-2 PG 16 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 659KF UT WOS:000181775300016 ER PT J AU Slavin, JA Lepping, RP Gjerloev, J Goldstein, ML Fairfield, DH Acuna, MH Balogh, A Dunlop, M Kivelson, MG Khurana, K Fazakerley, A Owen, CJ Reme, H Bosqued, JM AF Slavin, JA Lepping, RP Gjerloev, J Goldstein, ML Fairfield, DH Acuna, MH Balogh, A Dunlop, M Kivelson, MG Khurana, K Fazakerley, A Owen, CJ Reme, H Bosqued, JM TI Cluster electric current density measurements within a magnetic flux rope in the plasma sheet SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID GEOTAIL OBSERVATIONS; SUBSTORMS; EVOLUTION; MODEL AB [1] On August 22, 2001 all 4 Cluster spacecraft nearly simultaneously penetrated a magnetic flux rope in the tail. The flux rope encounter took place in the central plasma sheet, beta(i) similar to1-2, near the leading edge of a bursty bulk flow. The "time-of-flight'' of the flux rope across the 4 spacecraft yielded V(x) similar to 700 km/s and a diameter of similar to1 R(e). The speed at which the flux rope moved over the spacecraft is in close agreement with the Cluster plasma measurements. The magnetic field profiles measured at each spacecraft were first modeled separately using the Lepping-Burlaga force-free flux rope model. The results indicated that the center of the flux rope passed northward ( above) s/c 3, but southward (below) of s/c 1, 2 and 4. The peak electric currents along the central axis of the flux rope predicted by these single-s/c models were similar to15-19 nA/m(2). The 4-spacecraft Cluster magnetic field measurements provide a second means to determine the electric current density without any assumption regarding flux rope structure. The current profile determined using the curlometer technique was qualitatively similar to those determined by modeling the individual spacecraft magnetic field observations and yielded a peak current density of 17 nA/m(2) near the central axis of the rope. However, the curlometer results also showed that the flux rope was not force-free with the component of the current density perpendicular to the magnetic field exceeding the parallel component over the forward half of the rope, perhaps due to the pressure gradients generated by the collision of the BBF with the inner magnetosphere. Hence, while the single-spacecraft models are very successful in fitting flux rope magnetic field and current variations, they do not provide a stringent test of the force-free condition. C1 NASA, Extraterr Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ London Imperial Coll Sci Technol & Med, London SW7 2BZ, England. Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90024 USA. UCL, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England. Ctr Etud Spatiale Rayonnements, Toulouse, France. RP Slavin, JA (reprint author), NASA, Extraterr Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM james.a.slavin@gsfc.nasa.gov RI Owen, Christopher/C-2999-2008; dunlop, malcolm/F-1347-2010; Goldstein, Melvyn/B-1724-2008; Kivelson, Margaret/I-9019-2012; Slavin, James/H-3170-2012 OI Owen, Christopher/0000-0002-5982-4667; Kivelson, Margaret/0000-0003-3859-8581; Slavin, James/0000-0002-9206-724X NR 19 TC 55 Z9 57 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 2 PY 2003 VL 30 IS 7 AR 1362 DI 10.1029/2002GL016411 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 667MM UT WOS:000182236000005 ER PT J AU Schober, SE Sinks, TH Jones, RL Bolger, PM McDowell, M Osterloh, J Garrett, ES Canady, RA Dillon, CF Sun, Y Joseph, CB Mahaffey, KR AF Schober, SE Sinks, TH Jones, RL Bolger, PM McDowell, M Osterloh, J Garrett, ES Canady, RA Dillon, CF Sun, Y Joseph, CB Mahaffey, KR TI Blood mercury levels in US children and women of childbearing age, 1999-2000 SO JAMA-JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION LA English DT Article ID METHYLMERCURY EXPOSURE; FISH CONSUMPTION; POPULATION; DISEASE; HAIR AB Context Humans are exposed to methylmercury, a well-established neurotoxin, through fish consumption. The fetus is most sensitive to the adverse effects of, exposure. The extent of exposure to methylmercury in US women of reproductive age is not known. Objective To describe the distribution of blood mercury levels in US children and women of childbearing age and the association with sociodemographic characteristics and fish consumption. Design and Setting The 1999-2000 data from, the National Health and Nutrition Examination Survey, a cross-sectional survey of the noninstitutionalized US population. Participants In 1999-2000,1250 children aged 1 to 5 years and 2314 women aged 16 to 49 years were selected to participate in the survey. Household interviews, physical examinations, and blood mercury levels assessments were performed on 705 children (56% response rate) and 1709 women (74% response rate). Main Outcome Measure Blood concentration of total mercury. Results Blood mercury levels were approximately 3-fold higher in women compared with children. The geometric mean concentration of total blood mercury was 0.34 mug/L (95% confidence interval [CI], 0.30-0.39 mug/L) in children and 1.02 mug/L (95% Cl, 0.85-1.20 mug/L) in women. Geometric mean mercury levels were almost 4-fold higher among women who ate 3 or more servings of fish in the past 30 days compared with women who ate no fish in that period (1.94 mug/L vs 0.51 mug/L; P<.001). Conclusions Measures of mercury exposure in women of childbearing age and young children generally fall below levels of concern. However, approximately 8% of women had concentrations higher than the US Environmental Protection Agency's recommended reference dose (5.8 μg/L), below which exposures are considered to be without adverse effects. Women who are pregnant or who intend to become pregnant should follow federal and state advisories on consumption of fish. C1 Ctr Dis Control & Prevent, Natl Ctr Hlth Stat, Hyattsville, MD 20782 USA. Ctr Dis Control & Prevent, Natl Ctr Environm Hlth, Atlanta, GA USA. US FDA, Ctr Food Safety & Appl Nutr, College Pk, MD USA. Natl Marine Fisheries Serv, Natl Ocean & Atmospher Adm, Pascagoula, MS USA. Orkand Corp, Falls Church, VA USA. US EPA, Off Sci Coordinat & Policy, Off Prevent Pesticides & Tox Subst, Washington, DC 20460 USA. RP Schober, SE (reprint author), Ctr Dis Control & Prevent, Natl Ctr Hlth Stat, 3311 Toledo Rd,Room 4210, Hyattsville, MD 20782 USA. EM sschober@cdc.gov NR 35 TC 179 Z9 186 U1 1 U2 15 PU AMER MEDICAL ASSOC PI CHICAGO PA 515 N STATE ST, CHICAGO, IL 60610 USA SN 0098-7484 J9 JAMA-J AM MED ASSOC JI JAMA-J. Am. Med. Assoc. PD APR 2 PY 2003 VL 289 IS 13 BP 1667 EP 1674 DI 10.1001/jama.289.13.1667 PG 8 WC Medicine, General & Internal SC General & Internal Medicine GA 662JX UT WOS:000181944500030 PM 12672735 ER PT J AU Zypman, FR Ferrante, J Jansen, M Scanlon, K Abel, P AF Zypman, FR Ferrante, J Jansen, M Scanlon, K Abel, P TI Evidence of self-organized criticality in dry sliding friction SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Letter ID ASPERITIES; SURFACES; DYNAMICS AB This letter presents experimental results on unlubricated friction, which suggests that stick-slip is described by self-organized criticality (SOC). The data, obtained with a pin-on-disc tribometer examines the variation of the friction force as a function of time-or sliding distance. This is the first time that standard tribological equipment has been used to examine the possibility of SOC. The materials were matching pins and discs of aluminium loaded with 250, 500 and 1000 g masses, and matching M50 steel couples loaded with a 1000 g mass. An analysis of the data shows that the probability distribution of slip sizes follows a power law. In addition, the frequency power spectrum follows a 1/f(alpha) pattern with a in the range 1.1-1.3. We perform a careful analysis of all the properties, beyond the two just mentioned, which are required to imply the presence of SOC. Our data strongly support the existence of SOC for stick-slip in dry sliding friction. C1 Yeshiva Univ, Dept Phys, New York, NY 10033 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Yeshiva Univ, Dept Phys, 2495 Amsterdam Ave, New York, NY 10033 USA. NR 21 TC 21 Z9 21 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0953-8984 EI 1361-648X J9 J PHYS-CONDENS MAT JI J. Phys.-Condes. Matter PD APR 2 PY 2003 VL 15 IS 12 BP L191 EP L196 AR PII S0953-8984(03)58982-2 DI 10.1088/0953-8984/15/12/101 PG 6 WC Physics, Condensed Matter SC Physics GA 711BM UT WOS:000184718500001 ER PT J AU Maley, PD Pizzicaroli, JC AF Maley, PD Pizzicaroli, JC TI The visual appearance of the Iridium((R)) satellites SO ACTA ASTRONAUTICA LA English DT Article AB A new generation of communications satellites orbiting the Earth is presenting amateur astronomers and the general public with an exciting new experience-the ability to view objects that at times will be brighter than the brightest star or planet in the sky! Named the Iridium satellite constellation, this collection of artificial satellites circles the Earth 14 times daily. Each one is physically about the size of an automobile. Originally planned as a way for persons with portable telephones to communicate anywhere in the world using space-based technology, an unexpected feature of the design has caused the visual appearance of these spacecraft to reflect the light of the Sun like a giant mirror. While one might argue that the relative sameness of the night sky is rarely punctuated by anything dramatic, the Iridium satellites are about to change that view. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 NASA, Lyndon B Johnson Space Ctr, Astron Soc, Houston, TX 77058 USA. Motorola Satellite Commun Grp, Chandler, AZ USA. RP Maley, PD (reprint author), NASA, Lyndon B Johnson Space Ctr, Astron Soc, D05, Houston, TX 77058 USA. NR 2 TC 2 Z9 2 U1 1 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD APR PY 2003 VL 52 IS 8 BP 629 EP 639 AR PII S0094-5765(02)00127-3 DI 10.1016/S0094-5765(02)00127-3 PG 11 WC Engineering, Aerospace SC Engineering GA 654JG UT WOS:000181492000005 ER PT J AU Bushnell, DM AF Bushnell, DM TI Civil aeroautics: Problems, solutions, and revolutions SO AEROSPACE AMERICA LA English DT Article 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 3 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0740-722X J9 AEROSPACE AM JI Aerosp. Am. PD APR PY 2003 VL 41 IS 4 BP 28 EP 32 PG 5 WC Engineering, Aerospace SC Engineering GA 664QT UT WOS:000182072300008 ER PT J AU DeBonis, JR Scott, JN AF DeBonis, JR Scott, JN TI Comment on "Large-eddy simulation of a turbulent compressible round jet" vis-a-vis Lighthill's theory of jet noise - Reply by the authors to H. S. Ribner SO AIAA JOURNAL LA English DT Editorial Material C1 NASA, John H Glenn res Ctr, Nozzle Branch, Cleveland, OH 44135 USA. Ohio State Univ, Dept Aerosp Engn & Aviat, Columbus, OH 43210 USA. RP DeBonis, JR (reprint author), NASA, John H Glenn res Ctr, Nozzle Branch, 21000 Brookpk Rd,MS 86-7, Cleveland, OH 44135 USA. NR 0 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 APR PY 2003 VL 41 IS 4 BP 751 EP 751 DI 10.2514/2.2010 PG 1 WC Engineering, Aerospace SC Engineering GA 663VW UT WOS:000182027900024 ER PT J AU Srinivasan, RS Gerth, WA Powell, MR AF Srinivasan, RS Gerth, WA Powell, MR TI Mathematical model of diffusion-limited evolution of multiple gas bubbles in tissue SO ANNALS OF BIOMEDICAL ENGINEERING LA English DT Article DE mathematical modeling; multiple bubbles in tissue; decompression sickness ID DYNAMICS AB Models of gas bubble dynamics employed in probabilistic analyses of decompression sickness incidence in man must be theoretically consistent and simple, if they are to yield useful results without requiring excessive computations. They are generally formulated in terms of ordinary differential equations that describe diffusion-limited gas exchange between a gas bubble and the extravascular tissue surrounding it. In our previous model (Ann. Biomed. Eng. 30: 232-246, 2002), we showed that with appropriate representation of sink pressures to account for gas loss or gain due to heterogeneous blood perfusion in the unstirred diffusion region around the bubble, diffusion-limited bubble growth in a tissue of finite volume can be simulated without postulating a boundary layer across which gas flux is discontinuous. However, interactions between two or more bubbles caused by competition for available gas cannot be considered in this model, because the diffusion region has a fixed volume with zero gas flux at its outer boundary. The present work extends the previous model to accommodate interactions among multiple bubbles by allowing the diffusion region volume of each bubble to vary during bubble evolution. For given decompression and tissue volume, bubble growth is sustained only if the bubble number density is below a certain maximum. (C) 2003 Biomedical Engineering Society. C1 Wyle Labs, Life Sci Syst & Serv, Houston, TX 77058 USA. Navy Expt Diving Unit, Panama City, FL USA. NASA, Lyndon B Johnson Space Ctr, Barophysiol Lab, Houston, TX 77058 USA. RP Srinivasan, RS (reprint author), Wyle Labs, Life Sci Syst & Serv, 1290 Hercules Dr,Suite 120, Houston, TX 77058 USA. NR 20 TC 8 Z9 9 U1 2 U2 3 PU BIOMEDICAL ENGINEERING SOC AMER INST PHYSICS PI MELVILLE PA STE 1 NO 1, 2 HUNTINGTON QUADRANGLE, MELVILLE, NY 11747-4502 USA SN 0090-6964 J9 ANN BIOMED ENG JI Ann. Biomed. Eng. PD APR PY 2003 VL 31 IS 4 BP 471 EP 481 DI 10.1114/1.1561288 PG 11 WC Engineering, Biomedical SC Engineering GA 686RV UT WOS:000183335500011 PM 12723688 ER PT J AU Sheridan, PP Miteva, VI Brenchley, JE AF Sheridan, PP Miteva, VI Brenchley, JE TI Phylogenetic analysis of anaerobic psychrophilic enrichment cultures obtained from a Greenland glacier ice core SO APPLIED AND ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID 16S RIBOSOMAL-RNA; LAKE VOSTOK; BETA-GALACTOSIDASE; MICROBIAL LIFE; COPY NUMBER; BACTERIA; ANTARCTICA; DNA; AMPLIFICATION; SEDIMENTS AB The examination of microorganisms in glacial ice cores allows the phylogenetic relationships of organisms frozen for thousands of years to be compared with those of current isolates. We developed a method for aseptically sampling a sediment-containing portion of a Greenland ice core that had remained at -9degreesC for over 100,000 years. Epifluorescence microscopy and flow cytometry results showed that the ice sample contained over 6 X 10(7) cells/ml. Anaerobic enrichment cultures inoculated with melted ice were grown and maintained at -2degreesC. Genomic DNA extracted from these enrichments was used for the PCR amplification of 16S rRNA genes with bacterial and archaeal primers and the preparation of clone libraries. Approximately 60 bacterial inserts were screened by restriction endonuclease analysis and grouped into 27 unique restriction fragment length polymorphism types, and 24 representative sequences were compared phylogenetically. Diverse sequences representing major phylogenetic groups including alpha, beta, and gamma Proteobacteria as well as relatives of the Thermus, Bacteroides, Eubacterium, and Clostridium groups were found. Sixteen clone sequences were closely related to those from known organisms, with four possibly representing new species. Seven sequences may reflect new genera and were most closely related to sequences obtained only by PCR amplification. One sequence was over 12% distant from its closest relative and may represent a novel order or family. These results show that phylogenetically diverse microorganisms have remained viable within the Greenland ice core for at least 100,000 years. C1 Penn State Univ, Dept Biochem & Mol Biol, University Pk, PA 16802 USA. Penn State Univ, NASA, Astrobiol Inst, University Pk, PA 16802 USA. RP Miteva, VI (reprint author), Penn State Univ, Dept Biochem & Mol Biol, 211 S Frear, University Pk, PA 16802 USA. NR 40 TC 93 Z9 103 U1 1 U2 17 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1752 N ST NW, WASHINGTON, DC 20036-2904 USA SN 0099-2240 J9 APPL ENVIRON MICROB JI Appl. Environ. Microbiol. PD APR PY 2003 VL 69 IS 4 BP 2153 EP 2160 DI 10.1128/AEM.69.4.2153-2160.2003 PG 8 WC Biotechnology & Applied Microbiology; Microbiology SC Biotechnology & Applied Microbiology; Microbiology GA 665ZU UT WOS:000182151800037 PM 12676695 ER PT J AU Berendse, F Owens, SM Serlemitsos, PJ Tueller, J Chan, KW Soong, Y Krimm, H Baumgartner, WH Ogasaka, Y Tamura, K Okajima, T Tawara, Y Yamashita, K Misaki, K Kunieda, H AF Berendse, F Owens, SM Serlemitsos, PJ Tueller, J Chan, KW Soong, Y Krimm, H Baumgartner, WH Ogasaka, Y Tamura, K Okajima, T Tawara, Y Yamashita, K Misaki, K Kunieda, H TI Production and performance of the InFOC mu S 20-40-keV graded multilayer mirror SO APPLIED OPTICS LA English DT Article ID X-RAY TELESCOPE; FOCUSING TELESCOPE; MISSION; OPTICS AB The International Focusing Optics Collaboration for muCrab Sensitivity (InFOCmuS) balloonborne hard x-ray telescope incorporates graded Pt/C multilayers replicated onto segmented Al foils to obtain the significant effective area at energies previously inaccessible to x-ray optics. Reflectivity measurements of individual foils demonstrate our capability to produce a mass quantity of multilayered foils with a rms roughness of 0.5 nm. The effective area of the completed mirror is 78 and 22 cm(2) at 20 and 40 keV, respectively. The measured half-power diameter is 2.0 +/- 0.5 are min (90% confidence). The successful completion of this mirror demonstrates its applicability to future x-ray telescopes such as Constellation-X. (C) 2003 Optical Society of America. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland, Dept Astron, College Pk, MD 20740 USA. Univ Space Res Assoc, Washington, DC 20036 USA. Nagoya Univ, Dept Phys, Chikusa Ku, Nagoya, Aichi 4648602, Japan. Inst Space & Astronaut Sci, Kanagawa 2298510, Japan. RP NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM berendse@astro.umd.edu RI Tueller, Jack/D-5334-2012 NR 27 TC 14 Z9 14 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 APR 1 PY 2003 VL 42 IS 10 BP 1856 EP 1866 DI 10.1364/AO.42.001856 PG 11 WC Optics SC Optics GA 661ED UT WOS:000181877500016 PM 12683767 ER PT J AU Pottasch, SR Hyung, S Aller, LH Beintema, DA Bernard-Salas, J Feibelman, WA Klockner, HR AF Pottasch, SR Hyung, S Aller, LH Beintema, DA Bernard-Salas, J Feibelman, WA Klockner, HR TI Abundances of the planetary nebula Hu 1-2 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE ISM : abundances; planetary nebulae : individual : Hu 1-2; infrared : ISM; ISM : lines and bands ID CHEMICAL-COMPOSITION; LINE-INTENSITIES; EMISSION-LINES; CENTRAL STARS; SPECTRA; DISTANCES; ISO; TEMPERATURES; FLUXES AB The ISO and IUE spectra of the "elliptical" nebula Hu 1-2 are presented. These spectra are combined with new, high resolution spectra in the visual wavelength region to obtain a complete, extinction corrected, spectrum. The chemical composition of the nebula is then calculated and compared to previous determinations. The abundances determined are the lowest yet found in the analysis of ISO data. The evolutionary significance is discussed. C1 Kapteyn Astron Inst, NL-9700 AV Groningen, Netherlands. Chungbuk Natl Univ, Sch Sci Educ, CheongJu 361763, South Korea. Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. SRON, Natl Inst Space Res, NL-9700 AV Groningen, Netherlands. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Pottasch, SR (reprint author), Kapteyn Astron Inst, POB 800, NL-9700 AV Groningen, Netherlands. NR 39 TC 8 Z9 8 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 APR PY 2003 VL 401 IS 1 BP 205 EP 214 DI 10.1051/0004-6361:20020104 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 656MP UT WOS:000181611800018 ER PT J AU Kepler, SO Nather, RE Winget, DE Nitta, A Kleinman, SJ Metcalfe, T Sekiguchi, K Jiang, XJ Sullivan, D Sullivan, T Janulis, R Meistas, E Kalytis, R Krzesinski, J Ogloza, W Zola, S O'Donoghue, D Romero-Colmenero, E Martinez, P Dreizler, S Deetjen, J Nagel, T Schuh, SL Vauclair, G Ning, FJ Chevreton, M Solheim, JE Perez, JMG Johannessen, F Kanaan, A Costa, JE Costa, AFM Wood, MA Silvestri, N Ahrens, TJ Jones, AK Collins, AE Boyer, M Shaw, JS Mukadam, A Klumpe, EW Larrison, J Kawaler, S Riddle, R Ulla, A Bradley, P AF Kepler, SO Nather, RE Winget, DE Nitta, A Kleinman, SJ Metcalfe, T Sekiguchi, K Jiang, XJ Sullivan, D Sullivan, T Janulis, R Meistas, E Kalytis, R Krzesinski, J Ogloza, W Zola, S O'Donoghue, D Romero-Colmenero, E Martinez, P Dreizler, S Deetjen, J Nagel, T Schuh, SL Vauclair, G Ning, FJ Chevreton, M Solheim, JE Perez, JMG Johannessen, F Kanaan, A Costa, JE Costa, AFM Wood, MA Silvestri, N Ahrens, TJ Jones, AK Collins, AE Boyer, M Shaw, JS Mukadam, A Klumpe, EW Larrison, J Kawaler, S Riddle, R Ulla, A Bradley, P TI The everchanging pulsating white dwarf GD358 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars : white dwarfs; stars : variables : general; stars : oscillations; stars : individual : GD 358; stars : evolution ID ZZ-CETI STARS; WHOLE EARTH TELESCOPE; GRAVITY MODES; TURBULENT CONVECTION; GD-358; SPECTRA; PERIOD; G29-38; ASTEROSEISMOLOGY; INSTABILITY AB We report 323 hours of nearly uninterrupted time series photometric observations of the DBV star GD 358 acquired with the Whole Earth Telescope ( WET) during May 23rd to June 8th, 2000. We acquired more than 232 000 independent measurements. We also report on 48 hours of time-series photometric observations in Aug 1996. We detected the non-radial g-modes consistent with degree l = 1 and radial order 8 to 20 and their linear combinations up to 6th order. We also detect, for the first time, a high amplitude l = 2 mode, with a period of 796 s. In the 2000 WET data, the largest amplitude modes are similar to those detected with the WET observations of 1990 and 1994, but the highest combination order previously detected was 4th order. At one point during the 1996 observations, most of the pulsation energy was transferred into the radial order k = 8 mode, which displayed a sinusoidal pulse shape in spite of the large amplitude. The multiplet structure of the individual modes changes from year to year, and during the 2000 observations only the k = 9 mode displays clear normal triplet structure. Even though the pulsation amplitudes change on timescales of days and years, the eigenfrequencies remain essentially the same, showing the stellar structure is not changing on any dynamical timescale. C1 UFRGS, Inst Fis, Porto Alegre, RS, Brazil. Univ Texas, Dept Astron, Austin, TX 78712 USA. Univ Texas, McDonald Observ, Austin, TX 78712 USA. Apache Pt Observ, Sloan Digital Sky Survey, Sunspot, NM 88349 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Acad Sinica, Beijing Astron Observ, Beijing 100080, Peoples R China. Victoria Univ Wellington, Wellington, New Zealand. Inst Theoret Phys & Astron, LT-2600 Vilnius, Lithuania. Cracow Pedag Univ, Mt Suhora Observ, PL-30084 Krakow, Poland. Jagiellonian Univ, Krakow, Poland. S African Astron Observ, ZA-7935 Cape Town, South Africa. Univ Tubingen, D-72074 Tubingen, Germany. Univ Toulouse 3, Observ Midi Pyrenees, CNRS, UMR5572, F-31400 Toulouse, France. Observ Paris, DAEC, F-92195 Meudon, France. Inst Fys, N-9037 Tromso, Norway. Univ Fed Santa Catarina, Dept Fis, BR-88040900 Florianopolis, SC, Brazil. Florida Inst Technol, Dept Phys & Space Sci, Melbourne, FL 32901 USA. Florida Inst Technol, SARA Observ, Melbourne, FL 32901 USA. Univ Florida, Nucl Sci Ctr 202, Gainesville, FL 32611 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Univ Minnesota, Dept Phys & Astron, Minneapolis, MN 55455 USA. Univ Georgia, Dept Phys & Astron, Athens, GA 30602 USA. Middle Tennessee State Univ, Dept Phys & Astron, Murfreesboro, TN 37132 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. Univ Vigo, Dept Fis Aplicada, Fac Ciencias, Vigo 36200, Pontevedra, Spain. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Kepler, SO (reprint author), UFRGS, Inst Fis, Porto Alegre, RS, Brazil. EM kepler@if.ufrgs.br; travis@whitedwarf.org; kaz@subaru.naoj.org; jiang@astro.as.utexas.edu; zola@ao.uj.edu.pl; chevreton@obspm.fr; kanaan@fsc.ufsc.br; ulla@uvigo.es RI Metcalfe, Travis/A-9388-2008; Kepler, S. O. /H-5901-2012; Ulla Miguel, Ana Maria/M-2860-2014; OI Metcalfe, Travis/0000-0003-4034-0416; Kepler, S. O. /0000-0002-7470-5703; Kawaler, Steven/0000-0002-6536-6367 NR 45 TC 48 Z9 48 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 APR PY 2003 VL 401 IS 2 BP 639 EP 654 DI 10.1051/0004-6361:20030105 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 658EN UT WOS:000181708800026 ER PT J AU De Breuck, C Neri, R Morganti, R Omont, A Rocca-Volmerange, B Stern, D Reuland, M van Breugel, W Rottgering, H Stanford, SA Spinrad, H Vigotti, M Wright, M AF De Breuck, C Neri, R Morganti, R Omont, A Rocca-Volmerange, B Stern, D Reuland, M van Breugel, W Rottgering, H Stanford, SA Spinrad, H Vigotti, M Wright, M TI CO emission and associated HI absorption from a massive gas reservoir surrounding the z=3 radio galaxy B3 J2330+3927 SO ASTRONOMY & ASTROPHYSICS LA English DT Review DE galaxies : individual : B3 J2330+3927; galaxies : active; galaxies : formation; radio lines : galaxies; cosmology : observations ID ULTRA-STEEP-SPECTRUM; LUMINOUS INFRARED GALAXIES; ACTIVE GALACTIC NUCLEI; HIGH-REDSHIFT GALAXIES; DUST EMISSION; MOLECULAR GAS; CONTINUUM OBSERVATIONS; VLT SPECTROSCOPY; ALPHA EMISSION; SUBMILLIMETER AB We present results of a comprehensive multi-frequency study of the radio galaxy B3 J2330+ 3927. The 1."9 wide radio source, consisting of 3 components, is bracketed by 2 objects in our Keck K-band image. Optical and near-IR Keck spectroscopy of these two objects yield z = 3.087 +/- 0.004. The brightest ( K = 18.8) object has a standard type II AGN spectrum, and is the most likely location of the AGN, which implies a one-sided jet radio morphology. Deep 113 GHz observations with the IRAM Plateau de Bure Interferometer reveal CO J = 4-3 emission, which peaks at the position of the AGN. The CO line is offset by 500 km s(-1) from the systemic redshift of the AGN, but corresponds very closely to the velocity shift of an associated HI absorber seen in Lyalpha. This strongly suggests that both originate from the same gas reservoir surrounding the AGN host galaxy. Simultaneous 230 GHz interferometer observations find a similar to 3 x lower integrated flux density when compared to single dish 250 GHz observations with MAMBO at the IRAM 30 m telescope. This can be interpreted as spatially resolved thermal dust emission at scales of 0."5 to 6". Finally, we present a tau < 1.3% limit to the HI 21 cm absorption against the radio source, which represents the seventh nondetection out of 8 z > 2 radio galaxies observed to date with the WSRT. We present mass estimates for the atomic, neutral, and ionized hydrogen, and for the dust, ranging from M( H I) = 2 x 10(7) M-. derived from the associated HI absorber in Lyalpha up to M(H-2) = 7 x 10(10) M-. derived from the CO emission. This indicates that the host galaxy is surrounded by a massive reservoir of gas and dust. The K-band companion objects may be concentrations within this reservoir, which will eventually merge with the central galaxy hosting the AGN. C1 Inst Astrophys, CNRS, F-75014 Paris, France. Inst Radio Astron Millimetr, F-38406 St Martin Dheres, France. ASTRON, NL-7990 AA Dwingeloo, Netherlands. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. IGPP LLNL, Livermore, CA 94550 USA. Sterrewacht Leiden, NL-2300 RA Leiden, Netherlands. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. CNR, Ist Radioastron, I-40129 Bologna, Italy. Univ Calif Berkeley, Radio Astron Lab, Berkeley, CA 94720 USA. RP De Breuck, C (reprint author), Inst Astrophys, CNRS, 98Bis Blvd Arago, F-75014 Paris, France. OI De Breuck, Carlos/0000-0002-6637-3315 NR 112 TC 69 Z9 69 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 APR PY 2003 VL 401 IS 3 BP 911 EP 925 DI 10.1051/0004-6361:20030171 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 662DA UT WOS:000181929900011 ER PT J AU Mouchet, M Bonnet-Bidaud, JM Roueff, E Beuermann, K de Martino, D Desert, JM Ferlet, R Fried, RE Gansicke, BT Howell, SB Mukai, K Porquet, D Szkody, P AF Mouchet, M Bonnet-Bidaud, JM Roueff, E Beuermann, K de Martino, D Desert, JM Ferlet, R Fried, RE Gansicke, BT Howell, SB Mukai, K Porquet, D Szkody, P TI The surprising Far-UV spectrum of the polar BY Camelopardalis SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE accretion, stars : individual : BY Cam; white dwarfs; cataclysmic variables; binaries : close; X-rays : H0538+608; ultraviolet emission ID ULTRAVIOLET-SPECTROSCOPIC-EXPLORER; HUBBLE-SPACE-TELESCOPE; AM-HERCULIS; CATACLYSMIC VARIABLES; MOLECULAR-HYDROGEN; NOVA OUTBURST; WHITE-DWARF; H0538+608 =; STARS; ACCRETION AB We report on the first far-UV observations of the asynchronous polar BY Cam made by the Far-Ultraviolet Spectroscopic Explorer (FUSE). The source is known to exhibit the most extreme NV/CIV emission resonance line ratio observed among polars. The FUSE observations reveal a OVI resonance line weaker than in the prototype of polars, AM Her, with the absence of a detectable narrow component. The OVI broad line is detected with an equivalent width of the same order as in AM Her, the blueward doublet component is clearly present but the redward component is strongly affected by H(2) absorption. The presence of a strong NIII line and weak CIII lines also confirms the peculiar CNO line flux. We compare the resonance CNO line intensities with the predictions of the CLOUDY plasma code coupled to a geometrical model of the accretion column. Varying the temperature and/or intensity of the ionising spectrum is unable to reproduce the observed broad line ratios. A solution is obtained by significantly altering the element abundances with a strong depletion of C, overabundance of N and a weak underabundance of O. This confirms previous suggestions of non-solar abundances which may result from redistribution in the accreted material following nova outbursts and/or the secondary nuclear evolution. A very significant H(2) absorption is observed in front of the source, a possible indication for either the existence of a dense interstellar cloud or of circumstellar material. C1 CNRS, UMR 8102, F-92195 Meudon, France. Univ Paris 07, LUTH, Observ Paris, Sect Meudon, F-92195 Meudon, France. Univ Paris 07, F-75005 Paris, France. Ctr Etud Saclay, Serv Astrophys, DSM, DAPNIA,SAp, F-91191 Gif Sur Yvette, France. Univ Sternwarte Gottingen, D-37083 Gottingen, Germany. Osserv Astron Capodimonte, INAF, I-80131 Naples, Italy. CNRS, UMR 7095, F-75014 Paris, France. Univ Paris 06, Inst Astrophys Paris, F-75014 Paris, France. Braeside Observ, Flagstaff, AZ 86002 USA. Univ Southampton, Dept Phys & Astron, Southampton SO17 1BJ, Hants, England. Planetary Sci Inst, Astrophys Grp, Tucson, AZ 85705 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Max Planck Inst Extraterr Phys, D-85741 Garching, Germany. Univ Washington, Dept Astron, Seattle, WA 98195 USA. RP Mouchet, M (reprint author), CNRS, UMR 8102, F-92195 Meudon, France. EM martine.mouchet@obspm.fr RI Gaensicke, Boris/A-9421-2012; OI Gaensicke, Boris/0000-0002-2761-3005; Porquet, Delphine/0000-0001-9731-0352; de Martino, Domitilla/0000-0002-5069-4202 NR 40 TC 13 Z9 14 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD APR PY 2003 VL 401 IS 3 BP 1071 EP 1076 DI 10.1051/0004-6361:20030176 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 662DA UT WOS:000181929900026 ER PT J AU Ryans, RSI Dufton, PL Mooney, CJ Rolleston, WRJ Keenan, FP Hubeny, I Lanz, T AF Ryans, RSI Dufton, PL Mooney, CJ Rolleston, WRJ Keenan, FP Hubeny, I Lanz, T TI An analysis of the optical spectra of the post-asymptotic giant branch stars LSIV-12 111 and HD 341617 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars : abundances; stars : supergiants; stars : early-type; stars : fundamental parameters ID LTE LINE FORMATION; LATE-O-STARS; B-TYPE STARS; ELECTRON-IMPACT EXCITATION; HIGH GALACTIC LATITUDES; POINT-SOURCE CATALOG; PLANETARY-NEBULA; MU-M; ATMOSPHERIC PARAMETERS; SPECTROSCOPIC ANALYSIS AB High spectral resolution and signal-to-noise observations of the absorption and emission line spectra in two post-asymptotic-giant-branch (PAGB) stellar candidates, LSIV-12 111 and HD 314617 are discussed. The absorption line spectra have been analysed using non-LTE model atmosphere techniques to determine stellar atmospheric parameters and chemical compositions, both in absolute terms and relative to a standard star, HD 13841. The atmospheric parameters differ from previous estimates based on LTE model atmospheres, probably due to non-LTE effects. In turn these imply stellar masses that are generally larger than have been previously estimated. Both PAGB candidates have relative uniform underabundances of metals with mean values of -0.35 dex for LSIV-12 111 and -0.50 dex for HD 314617. Furthermore, their abundance patterns are remarkably similar to that observed for optically bright, F-type PAGBs. From the emission spectra, the plasma parameters and angular size of the circumstellar material are constrained, and these are consistent with previous estimates and with a PAGB evolutionary stage. C1 Queens Univ Belfast, Dept Pure & Appl Phys, Belfast BT7 1NN, Antrim, North Ireland. NASA, Astron & Solar Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Natl Opt Astron Observ, Tucson, AZ 85726 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. RP Ryans, RSI (reprint author), Queens Univ Belfast, Dept Pure & Appl Phys, Belfast BT7 1NN, Antrim, North Ireland. NR 84 TC 35 Z9 35 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 APR PY 2003 VL 401 IS 3 BP 1119 EP 1129 DI 10.1051/0004-6361:20030191 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 662DA UT WOS:000181929900032 ER PT J AU Motoki, M Sanuki, T Orito, S Abe, K Anraku, K Asaoka, Y Fujikawa, M Fuke, H Haino, S Imori, M Izumi, K Maeno, T Makida, Y Matsui, N Matsumoto, H Matsunaga, H Mitchell, J Mitsui, T Moiseev, A Nishimura, J Nozaki, M Ormes, J Saeki, T Sasaki, M Seo, ES Shikaze, Y Sonoda, T Streitmatter, R Suzuki, J Tanaka, K Ueda, I Wang, JZ Yajima, N Yamagami, T Yamamoto, A Yamamoto, Y Yamato, K Yoshida, T Yoshimura, K AF Motoki, M Sanuki, T Orito, S Abe, K Anraku, K Asaoka, Y Fujikawa, M Fuke, H Haino, S Imori, M Izumi, K Maeno, T Makida, Y Matsui, N Matsumoto, H Matsunaga, H Mitchell, J Mitsui, T Moiseev, A Nishimura, J Nozaki, M Ormes, J Saeki, T Sasaki, M Seo, ES Shikaze, Y Sonoda, T Streitmatter, R Suzuki, J Tanaka, K Ueda, I Wang, JZ Yajima, N Yamagami, T Yamamoto, A Yamamoto, Y Yamato, K Yoshida, T Yoshimura, K TI Precise measurements of atmospheric muon fluxes with the BESS spectrometer SO ASTROPARTICLE PHYSICS LA English DT Article DE atmospheric muon; atmospheric neutrino; superconducting spectrometer ID NEAR-EARTH ORBIT; COSMIC-RAY MUONS; SEA-LEVEL; MOMENTUM SPECTRUM; CHARGE RATIO; GROUND-LEVEL; ONBOARD BESS; RANGE 4; GEV-C; GEV/C AB The vertical absolute fluxes of atmospheric muons and muon charge ratio have been measured precisely at different geomagnetic locations by using the BESS spectrometer. The observations had been performed at sea level (30 m above sea level) in Tsukuba, Japan, and at 360 m above sea level in Lynn Lake, Canada. The vertical cutoff rigidities in Tsukuba (36.2degreesN, 140.1degreesE) and in Lynn Lake (56.5degreesN, 101.0degreesW) are 11.4 and 0.4 GV, respectively. We have obtained vertical fluxes of positive and negative muons in a momentum range from 0.6 to 20 GeV/c with systematic errors <3% in both measurements. By comparing the data collected at two different geomagnetic latitudes, we have seen an effect of cutoff rigidity. The dependence on the atmospheric pressure and temperature, and the solar modulation effect have been also clearly observed. We also clearly observed the decrease of charge ratio of muons at low momentum side with at higher cutoff rigidity region. (C) 2002 Elsevier Science B.V. All rights reserved. C1 Univ Tokyo, Tokyo 1130033, Japan. Kobe Univ, Kobe, Hyogo 6578501, Japan. High Energy Accelerator Res Org KEK, Tsukuba, Ibaraki 3050801, Japan. NASA, Goddard Space Flight Ctr, NASA, Greenbelt, MD 20771 USA. Univ Maryland, College Pk, MD 20742 USA. ISAS, Sagamihara, Kanagawa 2298510, Japan. RP Motoki, M (reprint author), Tohoku Univ, Res Ctr Neutrino Sci, Sendai, Miyagi 9808578, Japan. EM motoki@awa.tohoku.ac.jp RI MOTOKI, Masakazu/B-4212-2009; OI Seo, Eun-Suk/0000-0001-8682-805X NR 34 TC 54 Z9 54 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0927-6505 J9 ASTROPART PHYS JI Astropart Phys. PD APR PY 2003 VL 19 IS 1 BP 113 EP 126 DI 10.1016/S0927-6505(02)00195-0 PG 14 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 658CY UT WOS:000181705100008 ER PT J AU Bradford, CM Nikola, T Stacey, GJ Bolatto, AD Jackson, JM Savage, ML Davidson, JA Higdon, SJ AF Bradford, CM Nikola, T Stacey, GJ Bolatto, AD Jackson, JM Savage, ML Davidson, JA Higdon, SJ TI CO (J=7 -> 6) observations of NGC 253: Cosmic-ray-heated warm molecular gas SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : individual (NGC 253); galaxies : ISM; galaxies : nuclei; galaxies : starburst; ISM : molecules; submillimeter ID STARBURST GALAXY NGC-253; CARBON-MONOXIDE; DENSE GAS; NEARBY GALAXIES; ATOMIC CARBON; PHOTODISSOCIATION REGIONS; ROTATIONAL-EXCITATION; INTERSTELLAR-MEDIUM; NUCLEAR STARBURST; INFRARED-EMISSION AB We report observations of the CO J = 7 --> 6 transition toward the starburst nucleus of NGC 253. This is the highest excitation CO measurement in this source to date and allows an estimate of the molecular gas excitation conditions. Comparison of the CO line intensities with a large velocity gradient, escape probability model indicates that the bulk of the (2-5) x 10(7) M. of molecular gas in the central 180 pc is highly excited. A model with T similar to 120 K, n(H2) similar to 4.5 x 10(4) cm(-3), is consistent with the observed CO intensities, as well as the rotational H-2 lines observed with the Infrared Space Observatory. The inferred mass of warm, dense molecular gas is 10-30 times the atomic gas mass as traced through its [C II] and [O I] line emission. This large mass ratio is inconsistent with photodissociation region models in which the gas is heated by far-UV starlight. It is also not likely that the gas is heated by shocks in outflows or cloud-cloud collisions. We conclude that the best mechanism for heating the gas is cosmic rays, which provide a natural means of uniformly heating the full volume of molecular clouds. With the tremendous supernova rate in the nucleus of NGC 253, the cosmic-ray heating rate is at least similar to800 times greater than that in the Galaxy, more than sufficient to match the cooling observed in the CO lines. C1 Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. CALTECH, Div Phys Math & Astron, Pasadena, CA 91125 USA. Boston Univ, Inst Astrophys Res, Boston, MA 02215 USA. Univ Calif Berkeley, Radio Astron Lab, Berkeley, CA 94720 USA. NASA, Univ Space Res Assoc, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ London Queen Mary & Westfield Coll, Dept Phys, London E1 4NS, England. RP Bradford, CM (reprint author), Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. NR 58 TC 84 Z9 84 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 1 PY 2003 VL 586 IS 2 BP 891 EP 901 DI 10.1086/367854 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 658GP UT WOS:000181713500015 ER PT J AU Eskridge, PB Frogel, JA Taylor, VA Windhorst, RA Odewahn, SC Chiarenza, CATC Conselice, CJ de Grijs, R Matthews, LD O'Connell, RW Gallagher, JS AF Eskridge, PB Frogel, JA Taylor, VA Windhorst, RA Odewahn, SC Chiarenza, CATC Conselice, CJ de Grijs, R Matthews, LD O'Connell, RW Gallagher, JS TI Ultraviolet-optical pixel maps of face-on spiral galaxies: Clues for dynamics and star formation histories SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : individual (NGC 6753, NGC 6782); galaxies : photometry; galaxies : spiral; galaxies : structure; ultraviolet : galaxies ID H-II REGIONS; SURFACE PHOTOMETRY; RINGED GALAXIES; DISK GALAXIES; STELLAR; MORPHOLOGY; DECOMPOSITION; PROFILES; TELESCOPE; ABUNDANCE AB Ultraviolet and optical images of the face-on spiral galaxies NGC 6753 and NGC 6782 reveal regions of strong ongoing star formation that are associated with structures traced by the old stellar populations. We use these images to construct NUV-(NUV-I(814)) pixel color-magnitude diagrams (pCMDs) that reveal plumes of pixels with strongly varying near-ultraviolet (NUV) surface brightness and nearly constant I(814) surface brightness. The plumes correspond to sharply bounded radial ranges, with (NUV- I(814)) at a given NUV surface brightness being bluer at larger radii. The plumes are parallel to both the reddening vector and simple model mixtures of young and old populations, thus neither reddening nor the fraction of the young population can produce the observed separation between the plumes. The images and radial surface brightness and color plots indicate that the separate plumes are caused by sharp declines in the surface densities of the old populations at radii corresponding to disk resonances. The maximum surface brightness of the NUV light remains essentially constant with radius, while the maximum I(814) surface brightness declines sharply with radius. A mid-ultraviolet (MUV) image of NGC 6782 shows emission from the nuclear ring. The distribution of points in an (MUV-NUV)-(NUV-I(814)) pixel color-color diagram is broadly consistent with the simple mixture model but shows a residual trend that the bluest pixels in (MUV-NUV) are the reddest pixels in (NUV-I(814)). This may be due to a combination of red continuum from late-type supergiants and [S III] emission lines associated with H II regions in active star-forming regions. We have shown that pixel mapping is a powerful tool for studying the distribution and strength of ongoing star formation in galaxies. Deep, multicolor imaging can extend this to studies of extinction and the ages and metallicities of composite stellar populations in nearby galaxies. C1 Minnesota State Univ, Dept Phys & Astron, Trafton Sci Ctr N 141, Mankato, MN 56001 USA. Ohio State Univ, Dept Astron, McPherson Lab, Columbus, OH 43210 USA. NASA Headquarters, Washington, DC 20546 USA. Arizona State Univ, Dept Phys & Astron, Tempe, AZ 85287 USA. CALTECH, Dept Astron, Pasadena, CA 91125 USA. Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Virginia, Dept Astron, Charlottesville, VA 22903 USA. Univ Wisconsin, Dept Astron, Madison, WI 53706 USA. RP Eskridge, PB (reprint author), Minnesota State Univ, Dept Phys & Astron, Trafton Sci Ctr N 141, Mankato, MN 56001 USA. RI Conselice, Christopher/B-4348-2013; OI Conselice, Christopher/0000-0003-1949-7638; de Grijs, Richard/0000-0002-7203-5996 NR 45 TC 16 Z9 16 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 1 PY 2003 VL 586 IS 2 BP 923 EP 938 DI 10.1086/367820 PN 1 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 658GP UT WOS:000181713500017 ER PT J AU Naze, Y Hartwell, JM Stevens, IR Manfroid, J Marchenko, S Corcoran, MF Moffat, AFJ Skalkowski, G AF Naze, Y Hartwell, JM Stevens, IR Manfroid, J Marchenko, S Corcoran, MF Moffat, AFJ Skalkowski, G TI An X-ray investigation of the NGC 346 field in the Small Magellanic Cloud. II. The field population SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : star clusters; HII regions; Magellanic Clouds; X-rays : individual (NGC 346) ID CHANDRA; STARS; GAS; SMC; ABSORPTION; DISCOVERY; BINARIES; GALAXIES; NGC-346; CATALOG AB We present results from a Chandra observation of the NGC 346 cluster, which is the ionizing source of N66, the most luminous H II region and the largest star formation region in the SMC. In the first part of this investigation, we have analyzed the X-ray properties of the cluster itself and the remarkable star HD 5980, but the field contains additional objects of interest. In total, 75 X-ray point sources were detected in the Chandra observation: this is 5 times the number of sources detected by previous X-ray surveys. We investigate here their characteristics in detail. Because of high foreground absorption, the sources possess rather high hardness ratios. Their cumulative luminosity function appears generally steeper than that for the rest of the SMC at higher luminosities. Their absorption columns suggest that most of the sources belong to NGC 346. Using Digitized Sky Survey data and new UBVRI imaging with the ESO 2.2 m telescope, we also discovered possible counterparts for 32 of these X-ray sources and estimated a B spectral type for a large number of these counterparts. This tends to suggest that most of the X-ray sources in the field are in fact X-ray binaries. Finally, some objects show X-ray and/or optical variability, with a need for further monitoring. C1 Univ Liege, Inst Astrophys & Geophys, B-4000 Liege, Belgium. Univ Birmingham, Sch Phys & Astron, Birmingham B15 2TT, W Midlands, England. Western Kentucky Univ, Dept Phys & Astron, Bowling Green, KY 42101 USA. Univ Space Res Assoc, Seabrook, MD 20706 USA. NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Montreal, Dept Phys, Montreal, PQ H3C 3J7, Canada. RP Naze, Y (reprint author), Univ Liege, Inst Astrophys & Geophys, Allee 6 Aout 17,Bat B5C, B-4000 Liege, Belgium. EM naze@astro.ulg.ac.be; jmh@star.sr.bham.ac.uk; irs@star.sr.bham.ac.uk; manfroid@astro.ulg.ac.be; sergey@astro.wku.edu; corcoran@barnegat.gsfc.nasa.gov; moffat@astro.umontreal.ca; gwen@astro.umontreal.ca OI Naze, Yael/0000-0003-4071-9346 NR 33 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 APR 1 PY 2003 VL 586 IS 2 BP 983 EP 995 DI 10.1086/367831 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 658GP UT WOS:000181713500020 ER PT J AU Massa, D Fullerton, AW Sonneborn, G AF Massa, D Fullerton, AW Sonneborn, G TI Constraints on the ionization balance of hot-star winds from fuse observations of O stars in the Large Magellanic Cloud SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : individual (Large Magellanic Cloud, Small Magellanic Cloud); stars : early-type; stars : winds, outflows; ultraviolet : stars ID ULTRAVIOLET-SPECTROSCOPIC-EXPLORER; MASS-LOSS RATES; RADIATION-DRIVEN WINDS; UV-LINE-PROFILES; B-TYPE STARS; STELLAR WINDS; ORBIT PERFORMANCE; LUMINOUS STARS; ZETA-PUPPIS; SEI METHOD AB We present Far Ultraviolet Spectroscopic Explorer ( FUSE) spectra for 25 O stars in the Large Magellanic Cloud. We analyze wind profiles for the resonance lines from C III, N III, S IV, P V, S VI, and O VI in the FUSE range using a "Sobolev with exact integration'' method. In addition, the available data from either IUE or the Hubble Space Telescope for the resonance lines of Si IV, C IV, and N V are also modeled. Because several of the FUSE wind lines are unsaturated, the analysis provides meaningful optical depths ( or equivalently, mass-loss rate times ionization fractions, (M) over dot q) as a function of normalized velocity, w = v/v(infinity). Ratios of (M) over dot q (which are independent of (M) over dot) determine the behavior of the relative ionization as a function of w. The results demonstrate that, with the exception of O VI in all stars and S vi in the later stars, the ionization in the winds shifts toward lower ionization stages at higher w (contrary to the expectations of the nebular approximation). This result implies that the dominant production mechanism for O vi and S vi in the late O stars differs from the other ions. Using the Vink et al. relationship between stellar parameters and mass-loss rate, we convert the measurements into mean ionization fractions for each ion, [q(i)]. Because the derived ion fractions never exceed unity, we conclude that the derived values of (M) over dot M are not too small. However, q(P v), which is expected to be the dominant stage of ionization in some of these winds, is never greater than 0.20. This implies that either the calculated values of (M) over dot are too large, the assumed abundance of phosphorus is too large, or the winds are strongly clumped. The implications of each possibility are discussed. Correlations between the mean ion fractions and physical parameters such as T-eff, v(infinity), and the mean wind density, [rho], are examined. Two clear relationships emerge. First, as expected, the mean ionization fraction of the lower ions (C III, N III, Si IV, S IV) decreases with increasing T-eff. Second, the mean ion fraction of S vi in the latest stars and O VI in all stars increases with increasing v(infinity). This reaffirms the notion, first introduced by Cassinelli & Olson, that O VI is produced nonradiatively. Finally, we discuss specific characteristics of three stars, BI 272, BI 208, and Sk -67degrees166. For BI 272, the ionic species present in its wind suggest it is much hotter than its available ( uncertain) spectral type of O7: II-III:. In the case of BI 208, our inability to fit its observed profiles suggests that its wind is not spherically symmetric. For Sk -67degrees166, quantitative measurements of its line strengths confirm the suggestion by Walborn et al. that it is a nitrogen-rich O star. C1 NASA, SGT Inc, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Victoria, Dept Phys & Astron, Victoria, BC V8W 3P6, Canada. NASA, Astron & Solar Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Natl Res Council Canada, Herzberg Inst Astrophys, Victoria, BC V8X 4M6, Canada. RP Massa, D (reprint author), NASA, SGT Inc, Goddard Space Flight Ctr, Code 681-0, Greenbelt, MD 20771 USA. EM massa@taotaomona.gsfc.nasa.gov; awf@pha.jhu.edu; george.sonneborn@gsfc.nasa.gov RI Sonneborn, George/D-5255-2012 NR 84 TC 82 Z9 82 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 1 PY 2003 VL 586 IS 2 BP 996 EP 1018 DI 10.1086/367786 PN 1 PG 23 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 658GP UT WOS:000181713500021 ER PT J AU Moskalenko, IV Strong, AW Mashnik, SG AF Moskalenko, IV Strong, AW Mashnik, SG TI Challenging cosmic-ray propagation with antiprotons: Evidence for a "fresh'' nuclei component? SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic rays; diffusion; elementary particles; Galaxy : general; ISM : general nuclear, reactions; nucleosynthesis, abundances ID PRODUCTION CROSS-SECTIONS; LIQUID-HYDROGEN TARGET; ISOTOPIC COMPOSITION; HELIUM SPECTRA; LOCAL BUBBLE; VOYAGER MEASUREMENTS; RELATIVISTIC NUCLEI; MASS COMPOSITION; GALAXY; PROTON AB Recent measurements of the cosmic-ray (CR) antiproton flux have been shown to challenge existing CR propagation models. It was shown that the reacceleration models designed to match secondary/primary nuclei ratios (e.g., boron/carbon) produce too few antiprotons. Matching both the secondary/primary nuclei ratio and the antiproton flux requires artificial breaks in the diffusion coefficient and the primary injection spectrum, suggesting the need for other approaches. In the present paper we discuss one possibility to overcome these difficulties. Using the measured antiproton flux and B/C ratio to fix the diffusion coefficient, we show that the spectra of primary nuclei as measured in the heliosphere may contain a fresh, local, "unprocessed'' component at low energies, perhaps associated with the Local Bubble, thus decreasing the measured secondary/primary nuclei ratio. The independent evidence for supernova activity in the solar vicinity in the last few Myr supports this idea. The model reproduces antiprotons, B/C ratio, and elemental abundances up to Ni (Z less than or equal to 28). Calculated isotopic distributions of Be and B are in perfect agreement with CR data. The abundances of three "radioactive clock'' isotopes in CRs, Be-10, Al-26, and Cl-36, are all consistent and indicate a halo size z(h) similar to 4 kpc, based on the most accurate data taken by the ACE spacecraft. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Max Planck Inst Extraterr Phys, D-85740 Garching, Germany. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Maryland Baltimore Cty, Joint Ctr Astrophys, Baltimore, MD 21250 USA. RP Moskalenko, IV (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. EM igor.moskalenko@gsfc.nasa.gov; aws@mpe.mpg.de; mashnik@lanl.gov RI Moskalenko, Igor/A-1301-2007 OI Moskalenko, Igor/0000-0001-6141-458X NR 73 TC 66 Z9 66 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 1 PY 2003 VL 586 IS 2 BP 1050 EP 1066 DI 10.1086/367697 PN 1 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 658GP UT WOS:000181713500023 ER PT J AU Long, KS Reynolds, SP Raymond, JC Winkler, PF Dyer, KK Petre, R AF Long, KS Reynolds, SP Raymond, JC Winkler, PF Dyer, KK Petre, R TI Chandra CCD imagery of the northeast and northwest limbs of SN 1006 SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : individual (SN 1006); supernova remnants; X-rays : ISM ID SUPERNOVA REMNANT SN-1006; ULTRAVIOLET-ABSORPTION-LINES; X-RAY-EMISSION; NONLINEAR AMPLIFICATION; NONRADIATIVE SHOCKS; MAGNETIC-FIELD; COSMIC-RAYS; HIGH-ENERGY; ACCELERATION; INSTABILITIES AB We present deep images of the SN 1006 remnant (G327.6+14.6) with the ACIS instrument on the Chandra X-Ray Observatory. Two regions have been observed, the synchrotron-dominated northeast limb and the thermally dominated northwest limb, as well as a substantial portion of the interior of the remnant shell. The brightest features in the X-ray images correspond closely to radio features in the northeast and to Balmer-dominated. laments in the northwest. The spectra of the brighter. laments in the northeast are harder, with less prominent line emission than those in the northwest. In addition to highly elongated. laments, both images show enhanced clumps of emission well inside of the shock front that appear to be dominated by emission from oxygen. These probably arise from shock-heated ejecta, based on analysis of their X-ray spectra. We find no firm evidence for a halo of X-ray emission outside the shock to the northeast, as predicted by the Fermi shock-acceleration picture, in which relativistic electrons should be diffusing ahead of the shock. Our limits on upstream emission are less than 1.5% of the postshock levels in regions where the supernova remnant is brightest. This strongly suggests that the bright rims are flattened sheets nearly perpendicular to the plane of the sky and that the magnetic field strength jumps at the shock by a factor significantly larger than 4, as has been proposed if the shock puts significant energy into accelerating nonthermal ions. The spectra obtained of the northwest rim are all dominated by the helium-like ions of O, Ne, Mg, and Si expected from shocks with ionization (n(e)t) parameters of order 100 cm(-3) yr and electron temperatures of 0.5-1 keV, far lower than the postshock ion temperature implied by estimates of the shock speed obtained from the shape of the Halpha line. C1 Space Telescope Sci Inst, Baltimore, MD 21218 USA. N Carolina State Univ, Dept Phys, Raleigh, NC 27695 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Middlebury Coll, Dept Phys, Middlebury, VT 05753 USA. Natl Radio Astron Observ, Socorro, NM 87801 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Long, KS (reprint author), Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA. NR 39 TC 117 Z9 119 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 1 PY 2003 VL 586 IS 2 BP 1162 EP 1178 DI 10.1086/367832 PN 1 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 658GP UT WOS:000181713500031 ER PT J AU Nagasawa, M Lin, DNC Ida, S AF Nagasawa, M Lin, DNC Ida, S TI Eccentricity evolution of extrasolar multiple planetary systems due to the depletion of nascent protostellar disks SO ASTROPHYSICAL JOURNAL LA English DT Article DE celestial mechanics; planetary systems : formation; planetary systems : protoplanetary disks; stars : individual (v Andromedae, HD 168443) ID PRIMORDIAL SOLAR NEBULA; UPSILON-ANDROMEDAE; TIDAL INTERACTION; GIANT PLANETS; V-ANDROMEDAE; PROTOPLANETARY DISK; SECULAR RESONANCES; STABILITY ANALYSIS; GAP FORMATION; ACCRETION AB Most extrasolar planets are observed to have eccentricities much larger than those in the solar system. Some of these planets have sibling planets, with comparable masses, orbiting around the same host stars. In these multiple planetary systems, eccentricity is modulated by the planets' mutual secular interaction as a consequence of angular momentum exchange between them. For mature planets, the eigenfrequencies of this modulation are determined by their mass and semimajor axis ratios. However, prior to the disk depletion, self-gravity of the planets' nascent disks dominates the precession eigenfrequencies. We examine here the initial evolution of young planets' eccentricity due to the apsidal libration or circulation induced by both the secular interaction between them and the self-gravity of their nascent disks. We show that as the latter effect declines adiabatically with disk depletion, the modulation amplitude of the planets' relative phase of periapsis is approximately invariant despite the time-asymmetrical exchange of angular momentum between planets. However, as the young planets' orbits pass through a state of secular resonance, their mean eccentricities undergo systematic quantitative changes. For applications, we analyze the eccentricity evolution of planets around v Andromedae and HD 168443 during the epoch of protostellar disk depletion. We find that the disk depletion can change the planets' eccentricity ratio. However, the relatively large amplitude of the planets' eccentricity cannot be excited if all the planets had small initial eccentricities. C1 Univ Calif Santa Cruz, Univ Calif Observ, Lick Observ, Santa Cruz, CA 95064 USA. Tokyo Inst Technol, Dept Earth & Planetary Sci, Meguro Ku, Tokyo 1528551, Japan. RP Nagasawa, M (reprint author), NASA, Ames Res Ctr, Div Space Sci, MS 245-3, Moffett Field, CA 94035 USA. EM mnagasawa@mail.arc.nasa.gov; lin@ucolick.org; ida@geo.titech.ac.jp RI Ida, Shigeru/A-7840-2014 OI Ida, Shigeru/0000-0002-9676-3891 NR 53 TC 27 Z9 27 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 1 PY 2003 VL 586 IS 2 BP 1374 EP 1393 DI 10.1086/367884 PN 1 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 658GP UT WOS:000181713500049 ER PT J AU Cadavid, AC Lawrence, JK Berger, TE Ruzmaikin, A AF Cadavid, AC Lawrence, JK Berger, TE Ruzmaikin, A TI Photospheric sources and brightening of the internetwork chromosphere SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : chromosphere; Sun : magnetic fields; Sun : oscillations; Sun : photosphere ID SMALL-SCALE TOPOLOGY; SOLAR OSCILLATIONS; MAGNETIC-FIELD; GRAINS; DYNAMICS; POINTS; ATMOSPHERE; EXCITATION; WAVES; GRANULATION AB We analyze a unique 9 hr sequence of near-simultaneous, high-resolution and high-cadence G-band and K-line solar filtergrams, together with magnetograms of lower cadence and resolution. Our focus is on the phenomena surrounding discrete photospheric darkening "events" in internetwork G-band intensities. 72% of the darkenings are followed after 2 minutes by K-line brightenings. In the remaining cases, the darkenings are instead preceded by K-line brightenings 2 minutes earlier. Equivalent results are found when reference is shifted to K-line brightening events, although these two sets overlap by no more than 15%. The timing and coupling of the photospheric darkenings and chromospheric brightenings appear to be regulated by a preexisting 4 minute oscillation of the solar atmosphere. Other oscillations with periods in the range 1-8 minutes also are present, and in general the wave power is doubled at the time of an event. Our results favor an acoustic source for enhanced amplitudes of K-line intensity oscillations. The magnetic field acts as a passive tracer of horizontal photospheric flows that converge on the photospheric darkening events and then rebound. C1 Calif State Univ Northridge, Dept Phys & Astron, Northridge, CA 91330 USA. Lockheed Martin, Solar & Astrophys Lab, Palo Alto, CA 94304 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Cadavid, AC (reprint author), Calif State Univ Northridge, Dept Phys & Astron, Northridge, CA 91330 USA. EM ana.cadavid@csun.edu NR 34 TC 11 Z9 11 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 1 PY 2003 VL 586 IS 2 BP 1409 EP 1416 DI 10.1086/367833 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 658GP UT WOS:000181713500051 ER PT J AU Brosius, JW AF Brosius, JW TI Chromospheric evaporation and warm rain during a solar flare observed in high time resolution with the coronal diagnostic spectrometer aboard the Solar and Heliospheric Observatory SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : activity; Sun : corona; Sun : flares; Sun : UV radiation ID BRAGG CRYSTAL SPECTROMETER; X-RAY-BURSTS; MAXIMUM MISSION; IMPULSIVE PHASE; NUMERICAL SIMULATIONS; ATOMIC DATABASE; EMISSION-LINES; CA-XIX; PLASMA; TEMPERATURES AB We present EUV light curves, Doppler shifts, and line-broadening measurements for a flaring solar active region obtained with the Coronal Diagnostic Spectrometer (CDS) aboard the NASA ESA Solar and Heliospheric Observatory (SOHO) under conditions of (1) comprehensive temporal coverage (including the quiescent preflare, impulsive, and gradual decline phases), (2) high time resolution (9.83 s), and ( 3) narrow field of view (4" x 20"). The four strong lines of O III at 599.587 Angstrom, O v at 629.732 Angstrom, Mg x at 624.937 Angstrom, and Fe XIX at 592.225 Angstrom are analyzed and provide diagnostics of plasma dynamics for 4.9 less than or equal to log T less than or equal to 6.9. Wavelengths and widths measured during the preflare and late decline phases provide standards against which Doppler shifts and excess line broadening are measured during the impulsive and early decline phases. The entire pro. le of all four lines is blueshifted early during the impulsive rise of the. are, but only the O III, O V, and Mg x lines subsequently exhibit multiple components and down. ows. These down. ows provide evidence of "warm rain" due to cooling coronal. are plasma following chromospheric evaporation during the impulsive phase. O III and O V exhibit a pronounced precursor brightening during which the Fe XIX emission emerges above the noise; this, combined with the fact that the O III and O V intensities begin their impulsive rise earlier than do those of Mg X and Fe XIX, is consistent with the transport of coronal. are energy to the chromosphere by nonthermal particle beams. C1 NASA, Goddard Space Flight Ctr, Catholic Univ, Greenbelt, MD 20771 USA. RP Brosius, JW (reprint author), NASA, Goddard Space Flight Ctr, Catholic Univ, Code 682, Greenbelt, MD 20771 USA. NR 43 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 APR 1 PY 2003 VL 586 IS 2 BP 1417 EP 1429 DI 10.1086/367958 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 658GP UT WOS:000181713500052 ER PT J AU Jarosik, N Bennett, CL Halpern, M Hinshaw, G Kogut, A Limon, M Meyer, SS Page, L Pospieszalski, M Spergel, DN Tucker, GS Wilkinson, DT Wollack, E Wright, EL Zhang, Z AF Jarosik, N Bennett, CL Halpern, M Hinshaw, G Kogut, A Limon, M Meyer, SS Page, L Pospieszalski, M Spergel, DN Tucker, GS Wilkinson, DT Wollack, E Wright, EL Zhang, Z TI Design, implementation, and testing of the Microwave Anisotropy Probe radiometers SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE cosmic microwave background; instrumentation : detectors; space vehicles : instruments AB The Microwave Anisotropy Probe ( MAP) satellite, launched 2001 June 30, will produce full sky maps of the cosmic microwave background radiation in five frequency bands spanning 20-106 GHz. MAP contains 20 differential radiometers built with High Electron Mobility Transistor (HEMT) amplifiers with passively cooled input stages. The design and test techniques used to evaluate and minimize systematic errors and the prelaunch performance of the radiometers for all five bands are presented. C1 Princeton Univ, Dept Phys, Princeton, NJ 08544 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ British Columbia, Dept Phys, Vancouver, BC V6T 1Z4, Canada. Univ Chicago, Chicago, IL 60637 USA. Natl Radio Astron Observ, Charlottesville, VA 22903 USA. Princeton Univ, Dept Astrophys Sci, Princeton, NJ 08544 USA. Brown Univ, Dept Phys, Providence, RI 02912 USA. Univ Calif Los Angeles, Dept Astron, Los Angeles, CA 90095 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Jarosik, N (reprint author), Princeton Univ, Dept Phys, Jadwin Hall, Princeton, NJ 08544 USA. EM jarosik@pupgg.princeton.edu RI Kogut, Alan/D-6293-2012; Spergel, David/A-4410-2011; Wollack, Edward/D-4467-2012; OI Wollack, Edward/0000-0002-7567-4451; Limon, Michele/0000-0002-5900-2698 NR 11 TC 80 Z9 80 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD APR PY 2003 VL 145 IS 2 BP 413 EP 436 DI 10.1086/346080 PG 24 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 658HE UT WOS:000181714900008 ER PT J AU Hilliard-Robertson, PC Schneider, SM Bishop, SL Guilliams, ME AF Hilliard-Robertson, PC Schneider, SM Bishop, SL Guilliams, ME TI Strength gains following different combined concentric and eccentric exercise regimens SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article DE exercise; muscle loss; countermeasures ID HUMAN-MUSCLE AB Background: Loss of muscle strength and cross-sectional area is a well-recognized consequence of spaceflight. Existing countermeasures have not been fully effective in preventing muscle weakness and atrophy in microgravity. Resistance exercise programs that consist of both eccentric and concentric actions have resulted in strength and muscle mass gains in ground-based studies. Hypotheses: 1) A concentric/eccentric combination exercise regimen (with a bias of either concentric or eccentric exercise) will result in a greater strength gain than concentric exercise alone; and 2) an eccentrically biased regimen will result in the greatest strength gain of all. Methods: The 31 subjects were randomly assigned to one of three isokinetic exercise groups (CON-ECC: 75% concentric and 25% eccentric; ECC-CON: 75%, eccentric and 25% concentric; CON: 100% concentric); each subject trained the right leg 3 d per week for 5 wk. Pre- and post-training isokinetic concentric/ eccentric strength tests and DEXA scans assessed changes in muscle strength and/or mass. Results: All three groups showed an increase in eccentric muscle strength with the CON group showing the smallest gain (10.1%). Significantly larger gains were noted in the two combination groups (19.51%, 18.1'%; p < 0.042). with the largest gains in eccentric strength. No significant change was noted in muscle mass. Conclusions: A resistance exercise protocol which includes eccentric as well as concentric exercise, particularly when the eccentric exercise is emphasized, appears to result in greater strength gains than concentric exercise alone. Findings suggest eccentric exercise may be an important component of the in-flight resistance exercise protocol for long-duration spaceflight. C1 Univ Texas, Med Branch, Dept Prevent Med & Community Hlth, Galveston, TX 77555 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Bishop, SL (reprint author), Univ Texas, Med Branch, Dept Prevent Med & Community Hlth, 301 Univ Blvd,Rt 1150, Galveston, TX 77555 USA. NR 16 TC 4 Z9 5 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 APR PY 2003 VL 74 IS 4 BP 342 EP 347 PG 6 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA 662KL UT WOS:000181945800008 PM 12688453 ER PT J AU Kraft, NO Lyons, TJ Binder, H Inoue, N Ohshima, H Sekiguchi, C AF Kraft, NO Lyons, TJ Binder, H Inoue, N Ohshima, H Sekiguchi, C TI Exercise load index and changes in body weight during long-duration confinement in an isolated environment SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article DE space-analog environment; isolation-confinernent; exercise-load; adaptation; motivation; bodyweight ID PERFORMANCE; SPACE AB Purpose: The objectives of this project were to investigate exercise load and body weight related to long-duration confinement in a closed environment simulating ISS flight conditions, and to evaluate subjects' motivation to continue the experiment and their adaptation to isolation. Methods: Four Russian male subjects participated in a 240-d experiment (Group I), and four subjects (three male subjects and one female subject) from Austria, Canada, Japan, and Russia participated in a 110-d experiment (Group II). Exercise load was estimated during confinement using a modified Rating of Perceived Exertion scale. Free reports were used to determine subjects' motivation. Body weight was measured before, during, and after confinement. Results: Group I achieved their lowest exercise loads during their first month of isolation; problems with adaptation to the isolation environment were also reported during this first month. Group II exercise load was significantly lower in the second month due to crewmember problems; loss of motivation could be noted from their free reports. The subject with the lowest exercise load retired from the isolation experiment earlier than scheduled. Exercise load was not correlated with prior exercise habits. Significant differences in body weight was observed between group I and II and between Russian and non-Russian subjects. One subject in Group I experienced a significant increase in his body weight. Conclusion: Exercise load may be a good indicator for adaptation problems and motivation changes in closed environments. Immobility, lack of space, and smoking cessation in general did not induce significant body weight changes. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NASDA, Ned Res & Operat Off, Tsukuba, Ibaraki, Japan. Asian Off Aerosp R&D, Tokyo, Japan. RP Kraft, NO (reprint author), NASA, Ames Res Ctr, Mail Stop 262-4, Moffett Field, CA 94035 USA. NR 17 TC 1 Z9 1 U1 0 U2 0 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 USA SN 0095-6562 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD APR PY 2003 VL 74 IS 4 BP 348 EP 353 PG 6 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA 662KL UT WOS:000181945800009 PM 12688454 ER PT J AU Des Marais, DJ AF Des Marais, DJ TI Biogeochemistry of hypersaline microbial mats illustrates the dynamics of modern microbial ecosystems and the early evolution of the biosphere SO BIOLOGICAL BULLETIN LA English DT Article; Proceedings Paper CT Workshop on Outcomes of Genome-Genome Interactions CY MAY 01-03, 2002 CL MARINE BIOL LAB, WOODS HOLE, MASSACHUSETTS HO MARINE BIOL LAB ID CYANOBACTERIAL MATS; SULFATE REDUCTION; OXYGEN; PHOTOSYNTHESIS; ASSOCIATION; BACTERIUM; SULFIDE; CYCLES; SULFUR AB Photosynthetic microbial mats are remarkably complete self-sustaining ecosystems at the millimeter scale, yet they have substantially affected environmental processes on a planetary scale. These mats may be direct descendents Of the most ancient biological communities in which even oxygenic photosynthesis might have developed. Photosynthetic mats are excellent natural laboratories to help us to learn how microbial populations associate to control dynamic biogeochemical gradients. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Des Marais, DJ (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 31 TC 72 Z9 75 U1 1 U2 9 PU MARINE BIOLOGICAL LABORATORY PI WOODS HOLE PA 7 MBL ST, WOODS HOLE, MA 02543 USA SN 0006-3185 J9 BIOL BULL-US JI Biol. Bull. PD APR PY 2003 VL 204 IS 2 BP 160 EP 167 PG 8 WC Biology; Marine & Freshwater Biology SC Life Sciences & Biomedicine - Other Topics; Marine & Freshwater Biology GA 671HZ UT WOS:000182460500007 PM 12700147 ER PT J AU Metcalfe, A Desfaits, AC Salazkin, I Yahia, L Sokolowski, WM Raymond, J AF Metcalfe, A Desfaits, AC Salazkin, I Yahia, L Sokolowski, WM Raymond, J TI Cold hibernated elastic memory foams for endovascular interventions (vol 24, pg 491, 2003) SO BIOMATERIALS LA English DT Correction C1 CHUM Res Ctr, Notre Dame Hosp, Intervent Neuroradiol Lab, Montreal, PQ H2L 4M1, Canada. Ecole Polytech, Inst Biomed Engn, Montreal, PQ H3C 3A7, Canada. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Metcalfe, A (reprint author), CHUM Res Ctr, Notre Dame Hosp, Intervent Neuroradiol Lab, Mailloux Pavil M-8206,1560 Sherbrooke E, Montreal, PQ H2L 4M1, Canada. RI Raymond, Jean/D-3940-2011 NR 1 TC 4 Z9 4 U1 2 U2 9 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0142-9612 J9 BIOMATERIALS JI Biomaterials PD APR PY 2003 VL 24 IS 9 BP 1681 EP 1681 DI 10.1016/S0142-9612(02)00560-4 PG 1 WC Engineering, Biomedical; Materials Science, Biomaterials SC Engineering; Materials Science GA 645BY UT WOS:000180957400016 ER PT J AU Randall, D Krueger, S Bretherton, C Curry, J Duynkerke, P Moncrieff, M Ryan, B Starr, D Miller, M Rossow, W Tselioudis, G Wielicki, B AF Randall, D Krueger, S Bretherton, C Curry, J Duynkerke, P Moncrieff, M Ryan, B Starr, D Miller, M Rossow, W Tselioudis, G Wielicki, B TI Confronting models with data - The GEWEX cloud systems study SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID LARGE-SCALE MODELS; RESOLVING CONVECTION PARAMETERIZATION; SINGLE-COLUMN MODELS; LAYER MIXING SCHEME; BOUNDARY-LAYERS; GCSS MODEL; TOGA-COARE; ENTRAINMENT; CLIMATE; PARAMETRIZATION AB A,group of cloud modelers and global modelers has gradually learned how to make the most of the available observations. C1 Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. Univ Utah, Dept Meteorol, Salt Lake City, UT 84112 USA. Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. Univ Colorado, Dept Aerosp Engn Sci, Boulder, CO 80309 USA. Royal Netherlands Meteorol Inst, NL-3730 AE De Bilt, Netherlands. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. CSIRO, Div Atmospher Res, Canberra, ACT, Australia. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. European Ctr Medium Range Weather Forecasts, Reading RG2 9AX, Berks, England. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Randall, D (reprint author), Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. EM randall@redfish.atmos.colostate.edu RI Rossow, William/F-3138-2015; Randall, David/E-6113-2011 OI Randall, David/0000-0001-6935-4112 NR 40 TC 111 Z9 111 U1 1 U2 12 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD APR PY 2003 VL 84 IS 4 BP 455 EP 469 DI 10.1175/BAMS-84-4-455 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 670QP UT WOS:000182420400013 ER PT J AU Barsi, JA Schott, JR Palluconi, FD Heider, DL Hook, SJ Markham, BL Chander, G O'Donnell, EM AF Barsi, JA Schott, JR Palluconi, FD Heider, DL Hook, SJ Markham, BL Chander, G O'Donnell, EM TI Landsat TM and ETM+ thermal band calibration SO CANADIAN JOURNAL OF REMOTE SENSING LA English DT Article AB Landsat-5 has been imaging the Earth since March 1984, and Landsat-7 was added to the series of Landsat instruments in April 1999. The Landsat Project Science Office and the Landsat-7 Image Assessment System have been monitoring the on-board calibration of Landsat-7 since launch. Additionally, two separate university teams have been evaluating the on-board thermal calibration of Landsat-7 through ground-based measurements since launch. Although not monitored as closely over its lifetime, a new effort is currently being made to validate the calibration of Landsat-5. Two university teams are beginning to collect ground truth under Landsat-5, along with using other vicarious calibration methods to go back into the archive to validate the history of the calibration of Landsat-5. This paper considers the calibration efforts for the thermal band, band 6, of both the Landsat-5 and Landsat-7 instruments. Though stable since launch, Landsat-7 had an initial calibration error of about 3 K, and changes were made to correct for this beginning I October 2000 for data processed with the National Landsat Archive Production System (NLAPS) and beginning 20 December 2000 for data processed with the Landsat Product Generation System (LPGS). Recent results from Landsat-5 vicarious calibration efforts show an offset of -0.7 K over the lifetime of the instrument. This suggests that historical calibration efforts may have been detecting errors in processing systems rather than changes in the instrument. A correction to the Landsat-5 processing has not yet been implemented but will be in the near future. C1 NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, Greenbelt, MD 20771 USA. Rochester Inst Technol, Rochester, NY 14623 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. S Dakota State Univ, Dept Elect Engn, Brookings, SD 57007 USA. US Geol Survey, EROS Data Ctr, Raytheon Infroamt Technol & Sci Serv, Sioux Falls, SD 57198 USA. RP Barsi, JA (reprint author), NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, Code 923, Greenbelt, MD 20771 USA. RI Markham, Brian/M-4842-2013 OI Markham, Brian/0000-0002-9612-8169 NR 10 TC 62 Z9 64 U1 0 U2 3 PU CANADIAN AERONAUTICS SPACE INST PI OTTAWA PA 1685 RUSSELL RD, UNIT 1-R, OTTAWA, ON K1G 0N1, CANADA SN 0703-8992 J9 CAN J REMOTE SENS JI Can. J. Remote Sens. PD APR PY 2003 VL 29 IS 2 BP 141 EP 153 PG 13 WC Remote Sensing SC Remote Sensing GA 746MC UT WOS:000186749300002 ER PT J AU Andrefouet, S Robinson, JA Hu, CM Feldman, GC Salvat, B Payri, C Muller-Karger, FE AF Andrefouet, S Robinson, JA Hu, CM Feldman, GC Salvat, B Payri, C Muller-Karger, FE TI Influence of the spatial resolution of SeaWiFS, Landsat-7, SPOT, and International Space Station data on estimates of landscape parameters of Pacific Ocean atolls SO CANADIAN JOURNAL OF REMOTE SENSING LA English DT Article ID ARCHIPELAGO FRENCH-POLYNESIA; ACQUIRED ORBITAL PHOTOGRAPHS; SCALE; BOUNDARIES; PATTERN; IMAGERY; LAGOONS; CLASSIFICATION; DIVERSITY; METRICS AB Perimeter, surface area, total hydrodynamic aperture, and degree of hydrodynamic aperture are key landscape parameters used to quantify differences in the biological functioning of Tuamotu Archipelago atolls (French Polynesia). In a previous study, these landscape parameters were computed using Satellite pour l'observation de la terre (SPOT) high-resolution visible (HRV) data at 20 in spatial resolution. Since 1999, Tuamotu atolls have been systematically imaged by an array of satellite sensors with a wide range of spatial resolution (from I km to 5 in) including the sea-viewing wide field-of-view sensor (SeaWiFS), Landsat enhanced thematic mapper plus (ETM+), and digital photographs taken by astronauts from the International Space Station (ISS). Our goal was to assess the influence of the spatial resolution of SeaWiFS (I km), ETM+ (30 in), HRV (20 in), and ISS digital photographs (5 in) on the estimation of landscape parameters of Pacific Ocean atolls. Total hydrodynamic aperture and degree of hydrodynamic aperture are the parameters most sensitive to variation in resolution. For the same atoll, the differences between degree of aperture computed from SPOT and Landsat can reach 28%. Conversely, perimeters and atoll surface area estimates are in agreement within 7% using data with resolution from 5 to 30 in. One kilometre resolution SeaWiFS data offer the possibility to rank atolls based on surface area correctly, but only for atolls larger than 70 km(2). C1 Univ S Florida, Inst Marine Remote Sensing, St Petersburg, FL 33701 USA. NASA, Lyndon B Johnson Space Ctr, Earth Sci & Image Anal Lab, Houston, TX 77058 USA. NASA, Goddard Space Flight Ctr, SeaWiFS Project, Greenbelt, MD 20771 USA. Ecole Prat Hautes Etud, Perpignan, France. Univ Polynesie Francaise, Lab Terra Ocean, Tahiti, Fr Polynesia. RP Andrefouet, S (reprint author), Univ S Florida, Inst Marine Remote Sensing, St Petersburg, FL 33701 USA. RI hu, chuanmin/J-5021-2012; OI Robinson, Julie/0000-0002-6832-6459 NR 45 TC 14 Z9 14 U1 0 U2 5 PU CANADIAN AERONAUTICS SPACE INST PI OTTAWA PA 1685 RUSSELL RD, UNIT 1-R, OTTAWA, ON K1G 0N1, CANADA SN 0703-8992 J9 CAN J REMOTE SENS JI Can. J. Remote Sens. PD APR PY 2003 VL 29 IS 2 BP 210 EP 218 PG 9 WC Remote Sensing SC Remote Sensing GA 746MC UT WOS:000186749300007 ER PT J AU Ranson, KJ Kovacs, K Sun, G Kharuk, VI AF Ranson, KJ Kovacs, K Sun, G Kharuk, VI TI Disturbance recognition in the boreal forest using radar and Landsat-7 SO CANADIAN JOURNAL OF REMOTE SENSING LA English DT Article ID SIR-C/X-SAR; IMAGING RADAR; MAPPING DEFORESTATION; INITIAL OBSERVATIONS; IMAGERY; BACKSCATTER; DEFOLIATION; WILDFIRES; ECOSYSTEM; RONDONIA AB As part of a Siberian mapping project supported by the National Aeronautics and Space Administration (NASA), this study evaluated the capabilities of radars flown on the European Remote Sensing Satellite (ERS), Japanese Earth Resources Satellite (JERS), and Radarsat spacecraft and an optical sensor enhanced thematic mapper plus (ETM+) on-board Landsat-7 to detect fire scars, logging, and insect damage in the boreal forest. Using images from each sensor individually and combined, an assessment of the utility of using these sensors was developed. Transformed divergence analysis revealed that Landsat ETM+ images were the single best data type for this purpose. However, the combined use of the three radar and optical sensors did improve the results of discriminating these disturbances. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Sci Syst & Applicat Inc, Lanham, MD 20706 USA. Univ Maryland, Dept Geog, College Pk, MD 20742 USA. VN Sukachev Inst Forest, Krasnoyarsk, Russia. RP Ranson, KJ (reprint author), NASA, Goddard Space Flight Ctr, Code 923, Greenbelt, MD 20771 USA. RI Ranson, Kenneth/G-2446-2012 OI Ranson, Kenneth/0000-0003-3806-7270 NR 32 TC 42 Z9 47 U1 3 U2 18 PU CANADIAN AERONAUTICS SPACE INST PI OTTAWA PA 1685 RUSSELL RD, UNIT 1-R, OTTAWA, ON K1G 0N1, CANADA SN 0703-8992 J9 CAN J REMOTE SENS JI Can. J. Remote Sens. PD APR PY 2003 VL 29 IS 2 BP 271 EP 285 PG 15 WC Remote Sensing SC Remote Sensing GA 746MC UT WOS:000186749300012 ER PT J AU Kharuk, VI Ranson, KJ Kuz'michev, VV Im, S AF Kharuk, VI Ranson, KJ Kuz'michev, VV Im, S TI Landsat-based analysis of insect outbreaks in southern Siberia SO CANADIAN JOURNAL OF REMOTE SENSING LA English DT Article ID DEFOLIATION AB Landsat data were used to examine the effect of large-scale insect outbreaks in the forests of southern Siberia. Two insect outbreaks were studied: Ket-Chulym, similar to1.5 million hectares of forest damaged between 1954 and 1957; and Priangar'e, similar to0.5-0.7 million hectares of forest damaged between 1994 and 1996. Landsat scenes from 1980 to 2000 were analyzed. The optimal Landsat channels combination for detecting damage classes were bands 2 (0.525-0.605 mum), 4 (0.750-0.900 mum), 5 (1.55-1.75 mum), and 6 (10.40-12.50 mum). The damage to the forests caused an increase inradiometric temperature (20.20 +/- 0.04degreesC for damaged forests versus 19.47 +/- 0.02degreesC for healthy forests). The following pattern of forest succession was observed in the outbreak areas: dead stands with dense grass and shrub communities, burn scars, grass and shrub formations, open woodlands, closed young and middle-age birch stands, mature birch stands, and mixed conifer-deciduous stands. Forest regeneration goes through long-term species-change successions, and the rate depends on the size of the outbreak area. On-ground mapping after the outbreak and later Landsat analysis showed that even 45 years after the Ket-Chulym outbreak the area of forests did not increase. In the Priangar'e area approximately 45% of damaged forests have recovered. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. VN Sukachev Inst Forest, Krasnoyarsk, Russia. RP Ranson, KJ (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM kenneth.j.ranson@nasa.gov RI Ranson, Kenneth/G-2446-2012; Im, Sergei/J-2736-2016 OI Ranson, Kenneth/0000-0003-3806-7270; Im, Sergei/0000-0002-5794-7938 NR 15 TC 22 Z9 24 U1 1 U2 8 PU CANADIAN AERONAUTICS SPACE INST PI KANATA PA 350 TERRY FOX DR, STE 104, KANATA, ON K2K 2W5, CANADA SN 1712-7971 J9 CAN J REMOTE SENS JI Can. J. Remote Sens. PD APR PY 2003 VL 29 IS 2 BP 286 EP 297 PG 12 WC Remote Sensing SC Remote Sensing GA 746MC UT WOS:000186749300013 ER PT J AU Okai, K Tsue, M Kono, M Sato, J Dietrich, DL Williams, FA AF Okai, K Tsue, M Kono, M Sato, J Dietrich, DL Williams, FA TI An experimental study of microgravity combustion of a droplet near a wall SO COMBUSTION AND FLAME LA English DT Article DE droplet combustion; microgravity; cold wall effects ID SINGLE DROPLETS; PAIRS C1 Natl Aerosp Lab Japan, Chofu, Tokyo 1828522, Japan. Univ Tokyo, Bunkyo Ku, Tokyo 1138656, Japan. Ishikawajima Harima Heavy Ind Co Ltd, Tokyo 1358732, Japan. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Univ Calif San Diego, La Jolla, CA 92093 USA. RP Okai, K (reprint author), Natl Aerosp Lab Japan, 7-44-1 Jindaiji Higashi, Chofu, Tokyo 1828522, Japan. NR 9 TC 5 Z9 6 U1 1 U2 2 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0010-2180 J9 COMBUST FLAME JI Combust. Flame PD APR PY 2003 VL 133 IS 1-2 BP 169 EP 172 DI 10.1016/S0010-2180(02)00573-4 PG 4 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA 677XU UT WOS:000182835100013 ER PT J AU Zhan, XW Xue, YK Collatz, GJ AF Zhan, XW Xue, YK Collatz, GJ TI An analytical approach for estimating CO2 and heat fluxes over the Amazonian region SO ECOLOGICAL MODELLING LA English DT Article DE photosynthesis; stomatal conductance; CO2; energy balance; simplified biosphere model (SSiB); analytical solution; ABRACOS; LBA ID GENERAL-CIRCULATION MODEL; TERRESTRIAL CARBON METABOLISM; STOMATAL CONDUCTANCE; ATMOSPHERIC CO2; RAIN-FOREST; PHOTOSYNTHESIS; CLIMATE; LEAF; SIMULATIONS; EXCHANGE AB Accurate assessments of the CO2 fluxes between the terrestrial ecosystems and the atmosphere are pressingly needed for the climate change and carbon cycle studies. The Collatz et al. parameterization of leaf photosynthesis-stomatal conductance has been widely applied in land surface parameterization schemes for simulating the land surface CO2 fluxes. The study in this paper developed an analytical solution approach for the Collatz et al.'s parameterization for stable solution and computational efficiency. This analytical approach is then applied to the simplified biosphere model (SSiB), enhancing its capability of simulating land surface CO2 fluxes. The enhanced SSiB model is tested with field observation data sets from two Amazonian field experiments (ABRACOS missions and Manaus Eddy Covariance Study). Simulations of the land surface fluxes of latent heat, sensible heat and soil heat by the enhanced SSiB agree very well with observations with correlation coefficients being larger than 0.80. However, the correlation coefficient for the daily means Of CO2 fluxes is only 0.42 for the Manaus data set. A day-time, "square wave" in the simulated CO2 flux diurnal curves is found. The discrepancies between simulation and observation were found to be the results of incorrect parameter setup or improper leaf to canopy scaling strategy. A modification to the scaling strategy improves significantly the accuracy of the photosynthesis-stomatal conductance model. (C) 2002 Elsevier Science B.V. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, GEST,UMBC, Greenbelt, MD 20771 USA. Univ Calif Los Angeles, Dept Geog, Los Angeles, CA 90024 USA. RP Zhan, XW (reprint author), NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, GEST,UMBC, Code 974-1, Greenbelt, MD 20771 USA. EM xzhan@hab.gsfc.nasa.gov RI Zhan, Xiwu/F-5487-2010; collatz, george/D-5381-2012; Noojipady, Praveen/B-2511-2010 NR 44 TC 33 Z9 34 U1 0 U2 9 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-3800 EI 1872-7026 J9 ECOL MODEL JI Ecol. Model. PD APR 1 PY 2003 VL 162 IS 1-2 BP 97 EP 117 DI 10.1016/S0304-3800(02)00405-2 PG 21 WC Ecology SC Environmental Sciences & Ecology GA 671VH UT WOS:000182484700007 ER PT J AU Conway, EM AF Conway, EM TI Solar energy, technology policy, and institutional values. SO ENVIRONMENTAL HISTORY LA English DT Book Review RP Conway, EM (reprint author), NASA, Langley Res Ctr, Hampton, VA 23665 USA. NR 1 TC 0 Z9 0 U1 0 U2 1 PU ENVIRONMENTAL HISTORY PI DURHAM PA 701 VICKERS AVE, DURHAM, NC 27701-3147 USA SN 1084-5453 J9 ENVIRON HIST JI Environ. Hist. PD APR PY 2003 VL 8 IS 2 BP 338 EP 339 DI 10.2307/3985732 PG 2 WC Environmental Studies; History SC Environmental Sciences & Ecology; History GA 669LU UT WOS:000182353400025 ER PT J AU Visscher, PT Baumgartner, LK Buckley, DH Rogers, DR Hogan, ME Raleigh, CD Turk, KA Des Marais, DJ AF Visscher, PT Baumgartner, LK Buckley, DH Rogers, DR Hogan, ME Raleigh, CD Turk, KA Des Marais, DJ TI Dimethyl sulphide and methanethiol formation in microbial mats: potential pathways for biogenic signatures SO ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID METHYLATED SULFUR-COMPOUNDS; FRESH-WATER SEDIMENTS; SALT-MARSH SEDIMENTS; SULFATE REDUCTION; ANOXIC MARINE; DIMETHYLSULFONIOPROPIONATE; DIMETHYLSULFOXIDE; BIOGEOCHEMISTRY; CONSUMPTION; METABOLISM AB Mechanisms of dimethyl sulphide (DMS) and methanethiol (MT) production and consumption were determined in moderately hypersaline mats, Guerrero Negro, Mexico. Biological pathways regulated the net flux of DMS and MT as revealed by increases in flux resulting from decreased salinity, increased temperature and the removal of oxygen. Dimethylsulphoniopropionate (DMSP) was not present in these microbial mats and DMS and MT are probably formed by the reaction of photosynthetically produced low-molecular weight organic carbon and biogenic hydrogen sulphide derived from sulphate reduction. These observations provide an alternative to the notion that DMSP or S-containing amino acids are the dominant precursors of DMS in intertidal sediment systems. The major sink for DMS in the microbial mats was biological consumption, whereas photochemical oxidation to dimethylsulphoxide was the major sink for DMS in the overlying water column. Diel flux measurements demonstrated that significantly more DMS is released from the system during the night than during the day. The major consumers of DMS in the presence of oxygen were monooxygenase-utilizing bacteria, whereas under anoxic conditions, DMS was predominantly consumed by sulphate-reducing bacteria and methanethiol was consumed by methanogenic bacteria. Aerobic and anaerobic consumption rates of DMS were nearly identical. Mass balance estimates suggest that the consumption in the water column is likely to be smaller than net the flux from the mats. Volatile organic sulphur compounds are thus indicators of high rates of carbon fixation and sulphate reduction in these laminated sediment ecosystems, and atmospheric sulphur can be generated as a biogenic signature of the microbial mat community. C1 Univ Connecticut, Dept Marine Sci, Groton, CT 06340 USA. NASA, Astrobiol Inst, Washington, DC 20546 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Visscher, PT (reprint author), Univ Connecticut, Dept Marine Sci, Groton, CT 06340 USA. EM pieter.visscher@uconn.edu RI Rogers, Daniel/A-4904-2012; Buckley, Daniel/B-8089-2008; OI Visscher, Pieter/0000-0001-6911-1532 NR 57 TC 37 Z9 39 U1 3 U2 28 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 1462-2912 EI 1462-2920 J9 ENVIRON MICROBIOL JI Environ. Microbiol. PD APR PY 2003 VL 5 IS 4 BP 296 EP 308 DI 10.1046/j.1462-2920.2003.00418.x PG 13 WC Microbiology SC Microbiology GA 660XY UT WOS:000181861500009 PM 12662177 ER PT J AU Bakermans, C Tsapin, AI Souza-Egipsy, V Gilichinsky, DA Nealson, KH AF Bakermans, C Tsapin, AI Souza-Egipsy, V Gilichinsky, DA Nealson, KH TI Reproduction and metabolism at-10 degrees C of bacteria isolated from Siberian permafrost SO ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID ANTARCTIC SEA-ICE; 16S RDNA; FREEZING-POINT; DIVERSITY; RESISTANCE; LIFE AB We report the isolation and properties of several species of bacteria from Siberian permafrost. Half of the isolates were spore-forming bacteria unable to grow or metabolize at subzero temperatures. Other Gram-positive isolates metabolized, but never exhibited any growth at - 10degreesC. One Gram-negative isolate metabolized and grew at - 10degreesC, with a measured doubling time of 39 days. Metabolic studies of several isolates suggested that as temperature decreased below + 4degreesC, the partitioning of energy changes with much more energy being used for cell maintenance as the temperature decreases. In addition, cells grown at - 10degreesC exhibited major morphological changes at the ultrastructural level. C1 Univ So Calif, Dept Earth Sci, Los Angeles, CA 90089 USA. NASA, Jet Prop Lab, Pasadena, CA 91109 USA. Russian Acad Sci, Inst Physicochem & Biol Problems Soil Sci, Pushchino 142290, Moscow Region, Russia. RP Nealson, KH (reprint author), Univ So Calif, Dept Earth Sci, 3651 Trousdale Pkwy, Los Angeles, CA 90089 USA. EM knealson@usc.edu RI souza-egipsy, virginia/L-8389-2014 OI souza-egipsy, virginia/0000-0002-9690-9889 NR 31 TC 88 Z9 102 U1 5 U2 15 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 1462-2912 EI 1462-2920 J9 ENVIRON MICROBIOL JI Environ. Microbiol. PD APR PY 2003 VL 5 IS 4 BP 321 EP 326 DI 10.1046/j.1462-2920.2003.00419.x PG 6 WC Microbiology SC Microbiology GA 660XY UT WOS:000181861500011 PM 12662179 ER PT J AU Gaucher, EA Miyamoto, MM Benner, SA AF Gaucher, EA Miyamoto, MM Benner, SA TI Evolutionary, structural and biochemical evidence for a new interaction site of the leptin obesity protein SO GENETICS LA English DT Article ID BODY-WEIGHT; RECEPTOR; PROGRAM; GENE; GAIN; MICE AB The Leptin protein is central to the regulation of energy metabolism in mammals. By integrating evolutionary, structural, and biochemical information, a surface segment, outside of its known receptor contacts, is predicted as a second interaction site that may help to further define its roles in energy balance and its functional differences between humans and other mammals. C1 Univ Florida, Dept Chem, NASA, Astrobiol Inst, Gainesville, FL 32611 USA. Univ Florida, Fdn Appl Mol Evolut, Gainesville, FL 32611 USA. Univ Florida, Dept Zool, Gainesville, FL 32611 USA. RP Gaucher, EA (reprint author), Univ Florida, Dept Chem, NASA, Astrobiol Inst, 440 Leigh Hall, Gainesville, FL 32611 USA. RI Gaucher, Eric/I-7313-2013 NR 23 TC 27 Z9 28 U1 0 U2 3 PU GENETICS PI BALTIMORE PA 428 EAST PRESTON ST, BALTIMORE, MD 21202 USA SN 0016-6731 J9 GENETICS JI Genetics PD APR PY 2003 VL 163 IS 4 BP 1549 EP 1553 PG 5 WC Genetics & Heredity SC Genetics & Heredity GA 672JR UT WOS:000182517900028 PM 12702697 ER PT J AU Pizzarello, S Zolensky, M Turk, KA AF Pizzarello, S Zolensky, M Turk, KA TI Nonracemic isovaline in the Murchison meteorite: Chiral distribution and mineral association SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID RATIO MASS-SPECTROMETRY; RACEMIC AMINO-ACIDS; PEPTIDES; MURRAY; LIGHT AB The enantiomeric and carbon-isotopic composition of the amino acid isovaline have been analyzed in several samples of the Murchison meteorite and one sample of the Murray meteorite. L-Enantiomeric excesses of the amino acid were found to range from 0 to 15.2%, varying significantly both between meteorite stones and at short distances within a single stone. The upper limit of this range is the largest enantionteric excess measured to date for a biologically rare meteoritic amino acid and raises doubts that circularly polarized light irradiation could have been the sole cause of amino acids chiral asymmetry in meteorites. Individual D-and L-isovaline delta(13)C values ware found to be about + 18parts per thousand, with no significant differences between the two enantiomers to suggest terrestrial contamination. The amino acid relative abundance also varied between samples, with isovaline/alanine ratios of 0.5 to 6.5. X-ray diffraction analyses of contiguous meteorite fragments suggest a possible correlation between isovaline and hydrous silicates abundances. Copyright (C) 2003 Elsevier Science Ltd. C1 Arizona State Univ, Dept Chem & Biochem, Tempe, AZ 85287 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NASA, Ames Res Ctr, Stanford, CA 94305 USA. RP Pizzarello, S (reprint author), Arizona State Univ, Dept Chem & Biochem, Tempe, AZ 85287 USA. EM pizzar@asu.edu NR 27 TC 123 Z9 127 U1 1 U2 13 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD APR PY 2003 VL 67 IS 8 BP 1589 EP 1595 DI 10.1016/S0016-7037(00)01283-8 PG 7 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 666TA UT WOS:000182191500014 ER PT J AU van der Werf, GR Randerson, JT Collatz, GJ Giglio, L AF van der Werf, GR Randerson, JT Collatz, GJ Giglio, L TI Carbon emissions from fires in tropical and subtropical ecosystems SO GLOBAL CHANGE BIOLOGY LA English DT Article DE biomass burning; fire ecology; global carbon cycle; net primary production; TRMM ID ATMOSPHERIC EMISSIONS; BURNED AREAS; BIOMASS; FORESTS; TERRESTRIAL; BIOSPHERE; SATELLITE; SAVANNA; AFRICA; EXPRESSO AB Global carbon emissions from fires are difficult to quantify and have the potential to influence interannual variability and long-term trends in atmospheric CO2 concentrations. We used 4 years of Tropical Rainfall Measuring Mission (TRMM) Visible and Infrared Scanner (VIRS) satellite data and a biogeochemical model to assess spatial and temporal variability of carbon emissions from tropical fires. The TRMM satellite data extended between 38degreesN and 38degreesS and covered the period from 1998 to 2001. A relationship between TRMM fire counts and burned area was derived using estimates of burned area from other satellite fire products in Africa and Australia and reported burned areas from the United States. We modified the Carnegie-Ames-Stanford-Approach (CASA) biogeochemical model to account for both direct combustion losses and the decomposition from fire-induced mortality, using both TRMM and Sea-viewing Wide Field of view Sensor (SeaWiFS) satellite data as model drivers. Over the 1998-2001 period, we estimated that the sum of carbon emissions from tropical fires and fuel wood use was 2.6 Pg C yr(-1). An additional flux of 1.2 Pg C yr(-1) was released indirectly, as a result of decomposition of vegetation killed by fire but not combusted. The sum of direct and indirect carbon losses from fires represented 9% of tropical and subtropical net primary production (NPP). We found that including fire processes in the tropics substantially alters the seasonal cycle of net biome production by shifting carbon losses to months with low soil moisture and low rates of soil microbial respiration. Consequently, accounting for fires increases growing season net flux by similar to12% between 38degreesN and 38degreesS, with the greatest effect occurring in highly productive savanna regions. C1 NASA, Goddard Space Flight Ctr, USDA, FAS, Greenbelt, MD 20771 USA. CALTECH, Dept Geol & Planetary Sci, Pasadena, CA 91125 USA. CALTECH, Div Engn & Appl Sci, Pasadena, CA 91125 USA. NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, Greenbelt, MD 20771 USA. RP van der Werf, GR (reprint author), NASA, Goddard Space Flight Ctr, USDA, FAS, Code 923,Greenbelt Rd, Greenbelt, MD 20771 USA. EM guido@ltpmail.gsfc.nasa.gov RI collatz, george/D-5381-2012 NR 49 TC 263 Z9 276 U1 9 U2 56 PU BLACKWELL PUBLISHING LTD PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DG, OXON, ENGLAND SN 1354-1013 J9 GLOBAL CHANGE BIOL JI Glob. Change Biol. PD APR PY 2003 VL 9 IS 4 BP 547 EP 562 DI 10.1046/j.1365-2486.2003.00604.x PG 16 WC Biodiversity Conservation; Ecology; Environmental Sciences SC Biodiversity & Conservation; Environmental Sciences & Ecology GA 663MD UT WOS:000182008600007 ER PT J AU Scharringhausen, BR Nicholson, PD Brandl, B Hayward, TL Dekany, RG Troy, M Bloemhof, EE AF Scharringhausen, BR Nicholson, PD Brandl, B Hayward, TL Dekany, RG Troy, M Bloemhof, EE TI Adaptive optics observations of small moons of Saturn SO ICARUS LA English DT Article ID RING PLANE CROSSINGS; SATELLITES; SYSTEM AB We report near-infrared observations of Prometheus and Janus taken on 9 and 13 November 2000 (UT) with the Palomar Adaptive Optics System on the 5-m Hale telescope at Palomar Observatory. Dione, Rhea, and Tethys were used as guide "stars" for the adaptive optics system, and, though they were outside the isoplanatic patch of the region of interest, they allowed significant correction of the atmospheric turbulence. Prometheus, which is usually impossible to observe from the ground due to scattered light from the A ring, was imaged at superior conjunction with Saturn. At the time of the observations, the rings of Saturn were blocked by the southern limb of the planet while the moon passed just 0.35" below the planet's south pole. A K filter, in a methane absorption band, was used to suppress light from the disk of the planet, and template subtraction removed much of the scattered light from the A ring. Prometheus was found to be 21.9 +/- 0.1degrees of mean longitude behind the position predicted by Voyager-era ephemerides, consistent with the orbital lag discovered during the 1995 ring-plane crossing. (C) 2003 Elsevier Science (USA). All rights reserved. C1 Cornell Univ, Dept Astron, Ithaca, NY 14583 USA. Gemini Observ, La Serena, Chile. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Scharringhausen, BR (reprint author), Cornell Univ, Dept Astron, Ithaca, NY 14583 USA. NR 12 TC 0 Z9 0 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 APR PY 2003 VL 162 IS 2 BP 385 EP 390 DI 10.1016/S0019-1035(03)00027-7 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 673GQ UT WOS:000182572700012 ER PT J AU Goldreich, P Rappaport, N AF Goldreich, P Rappaport, N TI Chaotic motions of Prometheus and Pandora SO ICARUS LA English DT Article DE satellites of Saturn; orbits; chaos ID RING PLANE CROSSINGS; SMALL SATELLITES; SATURN; SYSTEM; ORBITS AB Recent HST images of the saturnian satellites Prometheus and Pandora show that their longitudes deviate from predictions of ephemerides based on Voyager images. Currently Prometheus is lagging and Pandora leading these predictions by somewhat more than 20degrees. We show that these discrepancies are fully accounted for by gravitational interactions between the two satellites. These peak every 24.8 days at conjunctions and excite chaotic perturbations. The Lyapunov exponent for the Prometheus-Pandora system is of order 0.3 year(-1) for satellite masses based on a nominal density of 0.63 g cm(-3). Interactions are strongest when the orbits come closest together. This happens at intervals of 6.2 years when their apses are antialigned. In this context, we note the sudden changes of opposite signs in the mean motions of Prometheus and Pandora at the end of 2000 occurred around the time their apsidal lines were antialigned. (C) 2003 Elsevier Science (USA). All rights reserved. C1 CALTECH, Pasadena, CA 91125 USA. Inst Adv Study, Princeton, NJ 08540 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Goldreich, P (reprint author), CALTECH, Pasadena, CA 91125 USA. NR 24 TC 28 Z9 29 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 APR PY 2003 VL 162 IS 2 BP 391 EP 399 DI 10.1016/S0019-1035(02)00080-5 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 673GQ UT WOS:000182572700013 ER PT J AU Hajela, G Cohen, F Dalton, P AF Hajela, G Cohen, F Dalton, P TI International space station power reinitialization SO IEEE AEROSPACE AND ELECTRONIC SYSTEMS MAGAZINE LA English DT Article AB The photovoltaic (PV) module on the International Space Station (ISS) has been operating since November 2000 and supporting electric power demands of the ISS and its crew of three. The PV module contains photovoltaic arrays that convert solar energy to electrical power, and an integrated equipment assembly (IEA) that houses electrical hardware and batteries for electric power regulation and storage. Each PV module contains two independent power channels for fault tolerance. Each power channel contains three batteries in parallel to meet its performance requirements and for fault tolerance. Each battery consists of 76 Nickel-Hydrogen (Ni-H-2) cells in series. These 76 cells are contained in two orbital replaceable units (ORU) connected in series. On-orbit data are monitored and trended to ensure that all hardware is operating normally. Review of on-orbit data showed that while five batteries are operating very well, one is showing signs of mismatched ORUs. The cell pressure in the two ORUs differs by an amount that exceeds the recommended range. The reason for this abnormal behavior may be that the two ORUs have a different use history. An assessment was performed and it was determined that capacity of this battery would be limited by the lower pressure ORU. Steps are being taken to reduce this pressure differential before battery capacity drops to the point of affecting its ability to meet performance requirements. As a first step, a battery reinitialization procedure was developed to reduce this pressure differential. The procedure was successfully carried out on-orbit and the pressure differential was reduced to the recommended range. This paper describes the battery performance and the consequences of mismatched ORUs that make a battery. The paper also describes the re-initialization procedure, how it was performed on-orbit, and battery performance after the re-initialization. On-orbit data monitoring and trending is an ongoing activity, and will continue as ISS assembly progresses. C1 Rocketdyne Power & Propuls, Boeing Co, Canoga Pk, CA 91309 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Hajela, G (reprint author), Rocketdyne Power & Propuls, Boeing Co, 6633 Canoga Ave, Canoga Pk, CA 91309 USA. NR 0 TC 0 Z9 0 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 0885-8985 J9 IEEE AERO EL SYS MAG JI IEEE Aerosp. Electron. Syst. Mag. PD APR PY 2003 VL 18 IS 4 BP 19 EP 24 DI 10.1109/MAES.2003.1194085 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA 666EW UT WOS:000182164900004 ER PT J AU Wheeler, KR Jorgensen, CC AF Wheeler, KR Jorgensen, CC TI Gestures as input: Neuroelectric joysticks and keyboards SO IEEE PERVASIVE COMPUTING LA English DT Article ID SPEECH RECOGNITION C1 NASA, Ames Res Ctr, Computat Sci Div, Human Senses Grp, Moffett Field, CA 94035 USA. NASA, Ames Res Ctr, Computat Sci Div, Neuroengn Lab, Moffett Field, CA 94035 USA. RP NASA, Ames Res Ctr, Computat Sci Div, Human Senses Grp, Moffett Field, CA 94035 USA. EM kevin.r.wheeler@nasa.gov; cjorgensen@mail.arc.nasa.gov NR 5 TC 33 Z9 33 U1 0 U2 2 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 1536-1268 EI 1558-2590 J9 IEEE PERVAS COMPUT JI IEEE Pervasive Comput. PD APR-JUN PY 2003 VL 2 IS 2 BP 56 EP 61 DI 10.1109/MPRV.2003.1203754 PG 6 WC Computer Science, Information Systems; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA 728UV UT WOS:000185735500010 ER PT J AU Savchenkov, AA Ilchenko, VS Handley, T Maleki, L AF Savchenkov, AA Ilchenko, VS Handley, T Maleki, L TI Second-order filter response with series-coupled silica microresonators SO IEEE PHOTONICS TECHNOLOGY LETTERS LA English DT Article DE fiber optics; filters; resonators ID WHISPERING-GALLERY MODES; RESONATORS; FIBERS AB We have demonstrated an approach for fabricating a photonic filter with second-order response function. The filter consists of two germania-doped silica microtoroidal or microspherical resonators cascaded in series. We use ultraviolet irradiation to tune the mode of one microcavity to bring it close to the mode of the second microcavity. This approach produces a filter function with much sharper rolloff than can be obtained with the individual microresonators. 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 16 TC 13 Z9 13 U1 0 U2 7 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 1041-1135 J9 IEEE PHOTONIC TECH L JI IEEE Photonics Technol. Lett. PD APR PY 2003 VL 15 IS 4 BP 543 EP 544 DI 10.1109/LPT.2003.809313 PG 2 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 661AL UT WOS:000181868900017 ER PT J AU Pogorzelski, RJ AF Pogorzelski, RJ TI On the design of coupling networks for coupled oscillator arrays SO IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION LA English DT Article DE coupling circuits; injection locked oscillators; phased arrays; voltage controlled oscillators ID DYNAMICS AB Arrays of voltage-controlled oscillators can be coupled by means of a network so as to mutually injection lock and thus oscillate as an ensemble. This ensemble may be used to excite the elements of a phased array antenna in such a manner as to radiate an agile beam. Design of the coupling network requires attention to three key parameters: the interoscillator coupling strength, the network bandwidth, and the oscillator loading. These parameters can be related to the network admittance matrix elements, which, in turn, are related to the lumped element values. This provides convenient formulas for use in designing networks, which provide the necessary values of the above three key design parameters. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Pogorzelski, RJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 12 TC 12 Z9 12 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0018-926X J9 IEEE T ANTENN PROPAG JI IEEE Trans. Antennas Propag. PD APR PY 2003 VL 51 IS 4 BP 794 EP 801 DI 10.1109/TAP.2003.811108 PG 8 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA 697FH UT WOS:000183931200016 ER PT J AU Simon, MK Alouini, MS AF Simon, MK Alouini, MS TI Average bit-error probability performance for optimum diversity combining of noncoherent FSK over Rayleigh fading channels SO IEEE TRANSACTIONS ON COMMUNICATIONS LA English DT Article DE error probability performance; noncoherent frequency-shift keying (FSK); optimum diversity combining; Rayleigh fading channel AB We derive the performance of the optimum noncoherent frequency-shift keying diversity combining receiver and compare it With that which implements the more traditional noncoherent postdetection equal gain combining scheme to reveal the degree of suboptimality of the latter. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Minnesota, Dept Elect & Comp Engn, Minneapolis, MN 55455 USA. RP Simon, MK (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 3 TC 17 Z9 17 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0090-6778 J9 IEEE T COMMUN JI IEEE Trans. Commun. PD APR PY 2003 VL 51 IS 4 BP 566 EP 569 DI 10.1109/TCOMM.2003.810849 PG 4 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA 678WK UT WOS:000182889500011 ER PT J AU Goebel, DM Schneider, AC Menninger, WL Weekley, JM AF Goebel, DM Schneider, AC Menninger, WL Weekley, JM TI Gain increases through end of life in traveling wave tubes SO IEEE TRANSACTIONS ON ELECTRON DEVICES LA English DT Article DE gain control; microwave amplifiers; traveling wave tubes ID PLASMA EDGE AB The fundamental mechanism for the observed gain increases in traveling wave tubes (TWTs) over burn-in and through end of life has been identified as a damage of the carbon attenuator material inside the tubes due to ion bombardment. The ions are generated by electron beam ionization of the finite base pressure generated in the, tube during operation by heating and electron-beam desorption of residual gases on the internal surfaces.. A theory that predicts this behavior was previously published and validated over burn-in for different families of tubes from S-Band through Ka-Band. Recently released life test data over periods of one to 15 years has shown the presence of very long-term gain increases of several dB in magnitude as predicted by this theory. In this paper, this data is presented and analyzed in terms of the gain growth theory. Predictions of very long-term gain increases through end of life of various TWTs are made based on these results. C1 Jet Prop Lab, Pasadena, CA 91109 USA. Boeing Elect Dynam Devices Inc, Torrance, CA 90505 USA. Boeing Satellite Syst, El Segundo, CA 90245 USA. RP Goebel, DM (reprint author), Jet Prop Lab, Pasadena, CA 91109 USA. NR 6 TC 3 Z9 3 U1 2 U2 4 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 APR PY 2003 VL 50 IS 4 BP 1117 EP 1124 DI 10.1109/TED.2003.812494 PG 8 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 695GB UT WOS:000183821800037 ER PT J AU Kaewpijit, S Le moigne, J El-Ghazawi, T AF Kaewpijit, S Le moigne, J El-Ghazawi, T TI Automatic reduction of hyperspectral imagery using wavelet spectral analysis SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE dimension reduction; maximum likelihood; remote sensing; wavelet decomposition ID CLASSIFICATION; DECOMPOSITION AB Hyperspectral imagery provides richer information about materials than multispectral imagery. The new larger data volumes from hyperspectral sensors present a challenge for traditional processing techniques. For example, the identification of each ground surface pixel by its corresponding spectral signature is still difficult because of the immense volume of data. Conventional classification methods may not be used without dimension reduction preprocessing. This is due to the curse of dimensionality, which refers to the fact that the sample size needed to estimate a function of several variables to a given degree of accuracy grows exponentially with the number of variables. Principal component analysis (PCA) has been the technique of choice for dimension reduction. However, PCA is computationally expensive and does not eliminate anomalies that can be seen at one arbitrary band. Spectral data reduction using automatic wavelet decomposition could be useful. This is because it preserves the distinctions among spectral signatures. It is also computed in automatic fashion and can filter data anomalies. This is due to the intrinsic properties of wavelet transforms that preserves high- and low-frequency features, therefore preserving peaks and valleys found in typical spectra. Compared to PCA, for the same level of data reduction, we show that automatic wavelet reduction yields. better or comparable classification accuracy for hyperspectral data, while achieving substantial computational savings. C1 George Washington Univ, Washington, DC 20052 USA. NASA, Goddard Space Flight Ctr, Appl Informat Sci Branch, Greenbelt, MD 20771 USA. RP Kaewpijit, S (reprint author), George Washington Univ, Washington, DC 20052 USA. NR 28 TC 103 Z9 117 U1 3 U2 17 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD APR PY 2003 VL 41 IS 4 BP 863 EP 871 DI 10.1109/TGRS.2003.810712 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 688BN UT WOS:000183412500014 ER PT J AU Gao, BC Yang, P Guo, G Park, SK Wiscombe, WJ Chen, B AF Gao, BC Yang, P Guo, G Park, SK Wiscombe, WJ Chen, B TI Measurements of water vapor and high clouds over the Tibetan Plateau with the Terra MODIS instrument SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE cirrus clouds; meteorology; remote sensing; Tibetan Plateau; water vapor ID CIRRUS CLOUDS; SATELLITE DATA; RADIANCES; RADIATION; CHANNEL; CLIMATE AB The seasonal variations of water vapor and cirrus clouds over the Tibetan Plateau are investigated using the recently available Level 3 monthly-mean atmospheric data products with a 1degrees x 1degrees latitude-longitude grid. The data products are derived from the multichannel imaging data acquired with the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra Spacecraft. It is shown that the water vapor concentration over the Tibetan Plateau is normally low, whereas high clouds (mainly cirrus clouds) over the Plateau occur quite frequently. On an annual scale, the water vapor concentration reaches its maximum in July and its minimum in January. During the summer season, the southeastern part of Tibetan Plateau, which can be affected by moistures originating from the Bay of Bengal and southeastern Asia, is slightly moister than the other parts of the Plateau. This observation is in agreement with the previous surface meteorological measurements by Chinese scientists from the 1950s to mid-1970s. The mean high-cloud reflectance over the Plateau reaches its maximum in April and minimum in November. This feature of high clouds over the Plateau has not been reported previously. The special channel centered at 1.375-mum on the MODIS instrument has allowed the observation. We present a plausible mechanism to explain the seasonal variations of high clouds over the Plateau. We expect that the water vapor and high-cloud measurements with MODIS can be used to improve the model initialization and validation for climate models involving the Tibetan Plateau and the nearby regions in Asia. C1 USN, Res Lab, Remote Sensing Div, Washington, DC 20375 USA. Texas A&M Univ, Dept Atmospher Sci, College Stn, TX 77843 USA. Ewha Womans Univ, Dept Environm Sci & Engn, Seoul 120750, South Korea. NASA, Goddard Space Flight Ctr, Climate & Radiat Branch, Greenbelt, MD 20771 USA. Univ Maryland, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21250 USA. RP Gao, BC (reprint author), USN, Res Lab, Remote Sensing Div, Code 7212, Washington, DC 20375 USA. RI Yang, Ping/B-4590-2011; Wiscombe, Warren/D-4665-2012 OI Wiscombe, Warren/0000-0001-6844-9849 NR 26 TC 23 Z9 25 U1 0 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 APR PY 2003 VL 41 IS 4 BP 895 EP 900 DI 10.1109/TGRS.2003.810704 PN 2 PG 6 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 688BR UT WOS:000183412900001 ER PT J AU Lau, KM Zhou, JY AF Lau, KM Zhou, JY TI Anomalies of the South American summer monsoon associated with the 1997-99 El Nino southern oscillation SO INTERNATIONAL JOURNAL OF CLIMATOLOGY LA English DT Article DE ENSO; South American summer monsoon; interannual variability; low-level jets ID SEA-SURFACE TEMPERATURE; ATLANTIC CONVERGENCE ZONE; NORTHEAST BRAZIL; TROPICAL ATLANTIC; INTERANNUAL VARIABILITY; CIRCULATION; RAINFALL; PRECIPITATION; CLIMATE; ALTIPLANO AB We describe the rainfall and circulation anomalies of the South American summer monsoon (SASM) during December-January-February (DJF) of 1997-98 (El Nino) and 1998-99 (La Nina). The most pronounced rainfall signals in DJF 1997-98 include (a) excessive rainfall over northern Peru and Ecuador, (b) deficient rainfall over northern and central Brazil, and (c) above-normal rainfall over southeastern subtropical South America. The rainfall anomalies in (a) and (b) are associated with the excitation of an anomalous east-west overturning cell with rising motion and low-level westerlies over the equatorial eastern Pacific, coupled to sinking motion and low-level easterlies over northern Brazil. The easterlies turn sharply southeastward on encountering the steep topography of the Andes, enhancing the summertime low-level jet (LLJ) along the eastern foothills of the Andes near 15-20degreesS, possibly contributing to the increased rainfall in (c). During DJF 1997-98, the sea-surface temperature-induced warming spreads and expands over the entire tropical troposphere. The eastward expansion of a warm upper tropospheric geopotential and temperature ridge from the Nino-3 region, across subtropical South America to the southeast Atlantic, enhances warming over the Altiplano Plateau, hydrostatically strengthening the Bolivia high. Similar to previous warming events, the South Pacific high is weakened, and the South Atlantic high is strengthened. During DJF 1998-99, as cold water develops over the equatorial central Pacific, the SASM anomalies in the tropics are weaker and less organized and appear to be in transition to the opposite phase to those found in DJF 97-98. In the subtropics, notable features include a weakening of the LLJ, a rainfall pattern associated with a poleward shift of the South Atlantic convergence zone, and development of the Pacific-South America teleconnection pattern. Published in 2003 by John Wiley Sons, Ltd. C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Univ Maryland, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21250 USA. RP Lau, KM (reprint author), NASA, Goddard Space Flight Ctr, Atmospheres Lab, Code 910, Greenbelt, MD 20771 USA. RI Lau, William /E-1510-2012 OI Lau, William /0000-0002-3587-3691 NR 32 TC 22 Z9 22 U1 1 U2 11 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0899-8418 J9 INT J CLIMATOL JI Int. J. Climatol. PD APR PY 2003 VL 23 IS 5 BP 529 EP 539 DI 10.1002/joc.900 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 671DF UT WOS:000182449500003 ER PT J AU Botella, O Shariff, K AF Botella, O Shariff, K TI B-spline methods in fluid dynamics SO INTERNATIONAL JOURNAL OF COMPUTATIONAL FLUID DYNAMICS LA English DT Article DE B-splines; Galerkin and collocation methods; mass matrix; fast solvers; block-structured grids; incompressible Navier-Stokes equations ID NAVIER-STOKES EQUATIONS; BOUNDARY-VALUE-PROBLEMS; FINITE-DIFFERENCE SCHEMES; MATRIX DECOMPOSITION ALGORITHMS; SEMIIMPLICIT PROJECTION METHODS; SEPARABLE ELLIPTIC-EQUATIONS; VISCOUS INCOMPRESSIBLE-FLOW; DIRECT NUMERICAL-SIMULATION; CONSISTENT MASS MATRIX; LARGE-EDDY SIMULATION AB Basis splines (B-splines) are basis functions for piecewise polynomials having a high level of derivative continuity. They possess attractive properties for complex flow simulations: they have compact support, provide a straightforward handling of boundary conditions and grid nonuniformities, yield numerical schemes with high resolving power, and the order of accuracy is a mere input parameter. This paper reviews progress made in the development and application of B-spline numerical methods to computational fluid dynamics. Basic approximation properties of B-spline schemes are discussed, and their relationship with conventional numerical methods is reviewed. Some fundamental developments towards spline methods in complex geometries are covered. These include local interpolation methods, fast solution algorithms on Cartesian grids, block-structured discretization and compatible pressure bases for the Navier-Stokes equations. Finally, application of some of these techniques to the computation of viscous incompressible flows is presented. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Stanford Univ, Ctr Turbulence Res, Stanford, CA 94305 USA. RP NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM shariff@nas.nasa.gov OI Shariff, Karim/0000-0002-7256-2497 NR 87 TC 7 Z9 7 U1 0 U2 3 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 2-4 PARK SQUARE, MILTON PARK, ABINGDON OR14 4RN, OXON, ENGLAND SN 1061-8562 EI 1029-0257 J9 INT J COMPUT FLUID D JI Int. J. Comput. Fluid Dyn. PD APR PY 2003 VL 17 IS 2 BP 133 EP 149 DI 10.1080/1061856031000104879 PG 17 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 666YL UT WOS:000182204000004 ER PT J AU Leu, MT AF Leu, MT TI Laboratory studies of interaction between trace gases and sulphuric acid or sulphate aerosols using flow-tube reactors SO INTERNATIONAL REVIEWS IN PHYSICAL CHEMISTRY LA English DT Review ID METASTABILITY PHASE-DIAGRAMS; HETEROGENEOUS REACTIONS; UPPER TROPOSPHERE; PEROXYACETYL NITRATE; HYDROGEN-CHLORIDE; HENRYS LAW; STRATOSPHERIC TEMPERATURES; ANTARCTIC STRATOSPHERE; DIFFUSION-COEFFICIENTS; REACTION PROBABILITIES AB Stratospheric ozone provides a protective shield for humanity and the global biosphere from harmful ultraviolet solar radiation. In past decades, theoretical models for the calculation of ozone balance frequently used gas-phase reactions alone in their studies. Since the discovery of the Antarctic ozone hole in 1985, however, it has been demonstrated that knowledge of heterogeneous reactions is needed to understand this significant natural event owing to the anthropogenic emission of chlorofluorocarbons. In this review I will briefly discuss the experimental techniques for the research of heterogeneous chemistry carried out in our laboratory. These experimental instruments include flow-tube reactors, an electron-impact ionization mass spectrometer, a chemical ionization mass spectrometer and a scanning mobility particle spectrometer. Numerous measurements of uptake coefficient (or reaction probability) and solubility of trace gases in liquid sulphuric acid have been performed under the ambient conditions in the upper troposphere and lower stratosphere, mainly 190-250 K and 40-80 wt% of H2SO4. The trace gases of atmospheric importance include N2O5, ClONO2, HCl, HOCl, HNO3, HONO, HO2NO2, CH3CO(O-2)NO2, CH3COCH3, CH3OH, and C2H5OH. In addition, the freezing phenomena of H2SO4, the thermodynamics of sulphuric acid monohydrate and the hydrolysis of N2O5 on sulphate aerosols will be briefly discussed. C1 CALTECH, Jet Prop Lab, Div Earth & Space Sci, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, Div Earth & Space Sci, Pasadena, CA 91109 USA. NR 97 TC 8 Z9 8 U1 0 U2 17 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 2-4 PARK SQUARE, MILTON PARK, ABINGDON OR14 4RN, OXON, ENGLAND SN 0144-235X EI 1366-591X J9 INT REV PHYS CHEM JI Int. Rev. Phys. Chem. PD APR-JUN PY 2003 VL 22 IS 2 BP 341 EP 376 DI 10.1080/0144235031000087282 PG 36 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 678CD UT WOS:000182846700004 ER PT J AU Satyanadh, G Joshi, R Abedin, N AF Satyanadh, G Joshi, R Abedin, N TI Monte Carlo calculations of the impulse response in bulk InAs for low-intensity photon avalanche detection at two micron wavelength (vol 41, pg 5559, 2002) SO JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS LA English DT Correction C1 Old Dominion Univ, Dept Elect & Comp Engn, Norfolk, VA 23529 USA. NASA, Langley Res Ctr, Aerosp Elect Syst Div, Electro Opt Branch, Hampton, VA 23681 USA. RP Satyanadh, G (reprint author), Old Dominion Univ, Dept Elect & Comp Engn, Norfolk, VA 23529 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU INST PURE APPLIED PHYSICS PI MINATO-KU TOKYO PA DAINI TOYOKAIJI BLDG, 4-24-8 SHINBASHI, MINATO-KU TOKYO, 105-004, JAPAN SN 0021-4922 J9 JPN J APPL PHYS 1 JI Jpn. J. Appl. Phys. Part 1 - Regul. Pap. Short Notes Rev. Pap. PD APR PY 2003 VL 42 IS 4A BP 1834 EP 1834 DI 10.1143/JJAP.42.1834A PG 1 WC Physics, Applied SC Physics GA 678XQ UT WOS:000182892300071 ER PT J AU Mellott, MM Elsbernd, VH AF Mellott, MM Elsbernd, VH TI TIMED: From concept to realization SO JOHNS HOPKINS APL TECHNICAL DIGEST LA English DT Article C1 NASA Headquarters, Washington, DC USA. RP Mellott, MM (reprint author), NASA Headquarters, Washington, DC USA. EM Mary.M.Mellott@nasa.gov; Victoria.H.Elsbernd@nasa.gov NR 0 TC 0 Z9 0 U1 0 U2 0 PU JOHNS HOPKINS UNIV PI LAUREL PA APPLIED PHYSICS LABORATORY ATTN: MANAGING EDITOR JOHN HOPKINS RD, BLDG 1-E254, LAUREL, MD 20723-6099 USA SN 0270-5214 J9 J HOPKINS APL TECH D JI Johns Hopkins APL Tech. Dig. PD APR-JUN PY 2003 VL 24 IS 2 BP 133 EP 135 PG 3 WC Engineering, Multidisciplinary SC Engineering GA 856VR UT WOS:000224073900002 ER PT J AU Clarke, ED Spear, LB Mccracken, ML Marques, FFC Borchers, DL Buckland, ST Ainley, DG AF Clarke, ED Spear, LB Mccracken, ML Marques, FFC Borchers, DL Buckland, ST Ainley, DG TI Validating the use of generalized additive models and at-sea surveys to estimate size and temporal trends of seabird populations SO JOURNAL OF APPLIED ECOLOGY LA English DT Article DE abundance estimates; common guillemot; model-based estimation; vector correction; waved albatross; western gull ID EGG-PRODUCTION METHOD; SPATIAL-DISTRIBUTION; CALIFORNIA CURRENT; COUNTING SEABIRDS; TROPICAL PACIFIC; SOUTHERN-OCEAN; FARMLAND BIRDS; ABUNDANCE; FISHERY; AGE AB 1. The population size of seabirds is often difficult to estimate from surveys at breeding colonies because of factors such as burrow nesting and nocturnal breeding. The reliability of alternative surveys conducted at sea has not previously been validated. Sample-based estimates from at-sea surveys could be biased and have poor precision due to non-random survey design and the uneven distribution of seabirds at sea. 2. We conducted at-sea surveys of western gulls Larus occidentalis and common guillemots Uria aalge of the Farallon Islands, California, USA, and waved albatrosses Phoebastria irrorata of the Galapagos. The observed counts were modelled using generalized additive models (GAMs), with a correction factor for bird movement relative to the ship included in an offset. The models were used to produce estimates of the size of the seabird populations at sea, which were compared with independent colony-based estimates, adjusted to account for the number of non-breeders. 3. Gull and guillemot populations were estimated separately for each of 10 survey years. Temporal trends were estimated by smoothing through the annual values. The albatross data from 7 survey years were pooled to obtain a single estimate of average population size. 4. The coefficients of variation (CVs) of the annual estimates were approximately 10%, 15-20% and 15-45% prior to smoothing for the albatross, gull and guillemot, respectively. The CVs of the smoothed estimates were about 10% for the gull and 15% for the guillemot. These represent substantial improvements in precision over previous sample-based estimates from at-sea surveys. 5. The colony-based estimates usually lay within the 95% confidence intervals (CIs) of both the annual and smoothed sea-based estimates, showing that the sea-based methods worked well. 6. Synthesis and applications. We conclude that GAMs of at-sea seabird survey data, collected under suitable protocols and corrected for bird movement, can accurately estimate population size. Given sufficient demographic information, these methods can provide a valuable tool for the management of populations that are difficult to census at the breeding colony. C1 Univ St Andrews, Ctr Res Ecol & Environm Modelling, Observ, St Andrews KY16 9LZ, Fife, Scotland. HT Harvey & Associates Ecol Consultants, San Jose, CA 95118 USA. Natl Marine Fisheries Serv, Honolulu Lab, Honolulu, HI 96822 USA. RP Clarke, ED (reprint author), Univ St Andrews, Ctr Res Ecol & Environm Modelling, Observ, Buchanan Gardens, St Andrews KY16 9LZ, Fife, Scotland. RI Buckland, Stephen/A-1998-2012 NR 53 TC 43 Z9 53 U1 1 U2 22 PU BLACKWELL PUBLISHING LTD PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DG, OXON, ENGLAND SN 0021-8901 J9 J APPL ECOL JI J. Appl. Ecol. PD APR PY 2003 VL 40 IS 2 BP 278 EP 292 DI 10.1046/j.1365-2664.2003.00802.x PG 15 WC Biodiversity Conservation; Ecology SC Biodiversity & Conservation; Environmental Sciences & Ecology GA 665KG UT WOS:000182118700008 ER PT J AU Skofronick-Jackson, GM Wang, JR Heymsfield, GM Hood, R Manning, W Meneghini, R Weinman, JA AF Skofronick-Jackson, GM Wang, JR Heymsfield, GM Hood, R Manning, W Meneghini, R Weinman, JA TI Combined radiometer-radar microphysical profile estimations with emphasis on high-frequency brightness temperature observations SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID WAVE IMAGING RADIOMETER; MEASURING MISSION TRMM; MICROWAVE RADIOMETER; DOPPLER RADAR; ICE CONTENT; CLOUD; RETRIEVALS; PRECIPITATION; WATER; LIDAR AB Information about the vertical microphysical cloud structure is useful in many modeling and predictive practices. Radiometers and radars are used to observe hydrometeor properties. This paper describes an iterative retrieval algorithm that combines the use of airborne active and wideband (10-340 GHz) passive observations to estimate the vertical content and particle size distributions of liquid and frozen hydrometeors. Airborne radar and radiometer observations from the third Convection and Moisture Experiment (CAMEX-3) were used in the retrieval algorithm as constraints. Nadir profiles were estimated for 1 min each of flight time (approximately 12.5 km along track) for anvil, convective, and quasi-stratiform clouds associated with Hurricane Bonnie (August 1998). The physically based retrieval algorithm relies on high frequencies (greater than or equal to150 GHz) to provide details on the frozen hydrometeors. Neglecting the high frequencies yielded acceptable estimates of the liquid profiles, but the ice profiles were poorly retrieved. The wideband observations were found to more than double the estimated frozen hydrometeor content as compared with retrievals using only 90 GHz and below. The convective and quasi-stratiform iterative retrievals quickly reached convergence. The complex structure of the frozen hydrometeors required the most iterations for convergence for the anvil cloud type. Nonunique profiles, within physical and theoretical bounds, were retrieved for thin anvil ice clouds. A qualitative validation using coincident in situ CAMEX-3 observations shows that the retrieved particle size distributions are well corroborated with independent measurements. C1 Univ Maryland Baltimore Cty, Baltimore, MD 21228 USA. NASA, Goddard Earth Sci & Technol Ctr, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Skofronick-Jackson, GM (reprint author), Univ Maryland Baltimore Cty, Baltimore, MD 21228 USA. RI Skofronick-Jackson, Gail/D-5354-2012 NR 29 TC 24 Z9 24 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD APR PY 2003 VL 42 IS 4 BP 476 EP 487 DI 10.1175/1520-0450(2003)042<0476:CRRMPE>2.0.CO;2 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 654YJ UT WOS:000181524300003 ER PT J AU Sohn, BJ Chung, ES Schmetz, J Smith, EA AF Sohn, BJ Chung, ES Schmetz, J Smith, EA TI Estimating upper-tropospheric water vapor from SSM/T-2 satellite measurements SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID BRIGHTNESS TEMPERATURES; RADIOMETRIC MEASUREMENTS; MICROWAVE RADIOMETRY; RELATIVE-HUMIDITY; RETRIEVAL; PROFILES; CHANNEL; CLIMATOLOGY; ALGORITHM; MOISTURE AB A method and a passive microwave retrieval algorithm have been developed to retrieve upper-tropospheric water vapor (UTW) from Special Sensor Microwave Water Vapor Profiler (SSM/T-2) measurements taken at three discrete frequencies near the 183-GHz water vapor line. The algorithm is based on physical relaxation utilizing statistical covariance information to provide initial-guess profiles and to constrain the updating step in the relaxation process. The scheme incorporates a method to remove SSM/T-2 brightness temperature bias in comparison with collocated simulated brightness temperatures. Correction functions are designed for the three SSM/T-2 183-GHz channels. The algorithm is validated against radiosonde observations and collocated SSM/T-2 brightness temperatures. Under clear-sky and nonprecipitating-cloud conditions, the UTW retrievals exhibit an rms error of 0.68 kg m(-2) with integrated water vapor biases below 5% for the upper-tropospheric layers of 700-500 and 500-200 hPa. The retrieval provides an independent source of satellite-derived water vapor information in the upper troposphere, distinct from upper-tropospheric humidity information retrieved from thermal infrared (IR) measurements around the 6.3-mum water vapor absorption band. The microwave retrievals can then be used to cross-check IR retrievals and/or to augment IR retrievals, dependent upon the problem at hand. C1 Seoul Natl Univ, Sch Earth & Environm Sci, Seoul 151747, South Korea. European Org Exploitat Meteorol Satellites, Darmstadt, Germany. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Sohn, BJ (reprint author), Seoul Natl Univ, Sch Earth & Environm Sci, Seoul 151747, South Korea. RI Chung, Eui-Seok/A-5757-2011 NR 44 TC 11 Z9 11 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD APR PY 2003 VL 42 IS 4 BP 488 EP 504 DI 10.1175/1520-0450(2003)042<0488:EUTWVF>2.0.CO;2 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 654YJ UT WOS:000181524300004 ER PT J AU Lang, S Tao, WK Simpson, J Ferrier, B AF Lang, S Tao, WK Simpson, J Ferrier, B TI Modeling of convective-stratiform precipitation processes: Sensitivity to partitioning methods SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID TROPICAL SQUALL-LINE; LATENT-HEAT RELEASE; ADVECTION TRANSPORT ALGORITHM; SMALL IMPLICIT DIFFUSION; TOGA-COARE; VERTICAL PROFILES; MOISTURE BUDGETS; CLOUD CLUSTERS; NUMERICAL SIMULATIONS; ANVIL CLOUDS AB Six different convective-stratiform separation techniques are compared and evaluated using 2D numerical simulations of a tropical and a midlatitude continental squall line. The techniques used include a texture algorithm applied to surface rainfall, a similar algorithm but with additional criteria applied to vertical velocity and cloud, a texture algorithm applied to vertical velocities below the melting layer, a simple approach that assumes a constant characteristic width for the convective region, a more sophisticated texture algorithm applied to radar reflectivities below the melting layer, and a new technique based on the premise that the fall speed of precipitation particles is large relative to air velocity in regions of stratiform precipitation. Comparisons are made in terms of rainfall, mass fluxes, apparent heating and moistening, hydrometeor contents, reflectivity and vertical-velocity contoured-frequency-with-altitude diagrams (CFAD), microphysics, and latent heating retrieval. Overall, it was found that the different separation techniques produced results that qualitatively agreed. However, the quantitative differences were significant. The texture algorithm applied to surface rain consistently produced the most stratiform rain while the texture algorithm applied to radar reflectivities below the melting layer and the new method comparing air velocities to terminal velocities consistently produced the most convective rain. The simple constant-area method performed comparably to the others in this squall line setting. Observational comparisons within the context of the model were unable to identify a superior technique. However, all of the methods were able to generate CFADs that were consistent with observations. Latent heating retrieval was shown to be sensitive to the use of separation technique mainly as a result of differences in the stratiform region. Methods that found very little stratiform rain resulted in exaggerated rain-normalized stratiform heating profiles. C1 NASA, Atmospheres Lab, Mesoscale Atmospher Proc Branch, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Sci Syst & Applicat Inc, Lanham, MD USA. NCEP Environm Modeling Ctr, Washington, DC USA. Sci Applicat Int Corp, Gen Sci Operat, Beltsville, MD USA. RP Lang, S (reprint author), NASA, Atmospheres Lab, Mesoscale Atmospher Proc Branch, Goddard Space Flight Ctr, Code 912, Greenbelt, MD 20771 USA. NR 58 TC 78 Z9 80 U1 0 U2 4 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 APR PY 2003 VL 42 IS 4 BP 505 EP 527 DI 10.1175/1520-0450(2003)042<0505:MOCSPP>2.0.CO;2 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 654YJ UT WOS:000181524300005 ER PT J AU Cartoixa, X Ting, DZY McGill, TC AF Cartoixa, X Ting, DZY McGill, TC TI Numerical spurious solutions in the effective mass approximation SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID ENVELOPE-FUNCTION APPROXIMATION; WELL INFRARED PHOTODETECTORS; LATTICE BAND-STRUCTURE; DOT-P THEORY; QUANTUM-WELL; SEMICONDUCTOR HETEROSTRUCTURES; OPTICAL-ABSORPTION; TUNNELING TIME; CONFINEMENT; BARRIER AB We have characterized a class of spurious solutions that appears when using the finite difference method to solve the effective mass approximation equations. We find that the behavior of these solutions as predicted by our model shows excellent agreement with numerical results. Using this interpretation we find a set of analytical expressions for conditions that the Luttinger parameters must satisfy to avoid spurious solutions. Finally, we use these conditions to check commonly used sets of parameters for their potential for generating this class of spurious solutions. (C) 2003 American Institute of Physics. C1 CALTECH, TJ Watson Jr Lab Appl Phys 128 95, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP McGill, TC (reprint author), CALTECH, TJ Watson Jr Lab Appl Phys 128 95, Pasadena, CA 91125 USA. EM tcm@ssdp.caltech.edu NR 46 TC 34 Z9 34 U1 1 U2 4 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 1 PY 2003 VL 93 IS 7 BP 3974 EP 3981 DI 10.1063/1.1555833 PG 8 WC Physics, Applied SC Physics GA 658PP UT WOS:000181729600038 ER PT J AU Strawa, AW Castaneda, R Owano, T Baer, DS Paldus, BA AF Strawa, AW Castaneda, R Owano, T Baer, DS Paldus, BA TI The measurement of aerosol optical properties using continuous wave cavity ring-down techniques SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID CLIMATE; EXTINCTION; ABSORPTION; CLOSURE; ACE-2 AB Large uncertainties in the effects that aerosols have on climate require improved in situ measurements of extinction coefficient and single-scattering albedo. This paper describes the use of continuous wave cavity ring-down (CW-CRD) technology to address this problem. The innovations in this instrument are the use of CW-CRD to measure aerosol extinction coefficient, the simultaneous measurement of scattering coefficient, and its small size, suitable for a wide range of aircraft applications. The prototype instrument measures extinction and scattering coefficient at 690 nm and extinction coefficient at 1550 nm. The instrument itself is small (60 cm x 48 cm x 15 cm) and relatively insensitive to vibrations. The prototype instrument has been tested in the lab and used in the field. While improvements in performance are needed, the prototype has been shown to make accurate and sensitive measurements of extinction and scattering coefficients. Combining these two parameters, one can obtain the single-scattering albedo and absorption coefficient, both important aerosol properties. The use of two wavelengths also allows a quantitative idea of the size of the aerosol to be obtained through the Angstrom exponent. Minimum sensitivity of the prototype instrument is 1.5 x 10-(6) m(-1) (1.5 Mm(-1)). Validation of the measurement of extinction coefficient has been accomplished by comparing the measurement of calibration spheres with Mie calculations. This instrument and its successors have potential to help reduce uncertainty currently associated with aerosol optical properties and their spatial and temporal variation. Possible applications include studies of visibility, climate forcing by aerosol, and the validation of aerosol retrieval schemes from satellite data. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Picarro Inc, Sunnyvale, CA USA. RP Strawa, AW (reprint author), NASA, Ames Res Ctr, Mail Stop 245-4, Moffett Field, CA 94035 USA. NR 32 TC 73 Z9 79 U1 1 U2 18 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD APR PY 2003 VL 20 IS 4 BP 454 EP 465 DI 10.1175/1520-0426(2003)20<454:TMOAOP>2.0.CO;2 PG 12 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 665EX UT WOS:000182107600003 ER PT J AU Hook, SJ Prata, FJ Alley, RE Abtahi, A Richards, RC Schladow, SG Palmarsson, SO AF Hook, SJ Prata, FJ Alley, RE Abtahi, A Richards, RC Schladow, SG Palmarsson, SO TI Retrieval of lake bulk and skin temperatures using Along-Track Scanning Radiometer (ATSR-2) data: A case study using Lake Tahoe, California SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID SEA-SURFACE TEMPERATURE; SATELLITE RETRIEVALS; WIND-SPEED; VALIDATION; TRANSPORT; ELIMINATION; VARIABILITY; SHEAR; BIAS AB In 1999, four monitoring stations were permanently moored on Lake Tahoe, California-Nevada. Each monitoring station provides near-real-time measurements of the surface skin temperature and bulk temperature on a near-continuous basis. Day and night data, acquired over Lake Tahoe from March to August 2000 with the second Along-Track Scanning Radiometer (ATSR-2), have been analyzed, and sets of coefficients for recovering the skin temperature and bulk temperature of the lake have been derived. The field measurements indicate that there is a noticeable difference between the bulk and skin temperatures (skin effect), which varies over the diurnal cycle. At the time of the ATSR-2 daytime overpass, the skin temperatures are on average 0.11degreesC cooler than the daytime bulk temperatures. At the time of the nighttime ATSR-2 overpass, the skin temperatures are on average 0.46degreesC cooler than the nighttime bulk temperatures. The smaller skin effect during the day is attributed to strong solar heating and low wind speeds at the site in the morning. The standard errors for recovering the daytime bulk and nighttime bulk temperatures, by regressing the in situ measurements against the average ATSR-2 nadir 11- and 12-mum channel brightness temperatures, are 0.40degrees and 0.18degreesC, respectively. By comparison the standard errors for recovering the daytime skin and nighttime skin temperatures by the same approach are 0.33degrees and 0.28degreesC, respectively. The lower standard error obtained for recovery of the skin and bulk temperatures at night is attributed to the lake surface being more homogeneous with the absence of solar heating. A comparison between the measured skin temperatures, skin temperature recovered by an ATSR-2 two-channel sea surface temperature algorithm, and the in situ regression indicates that the ATSR-2 algorithm has a similar scatter to the in situ linear regression but is offset with respect to the measured skin temperatures. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif Davis, Tahoe Res Grp, Dept Environm Sci & Policy, Davis, CA 95616 USA. Univ Calif Davis, Dept Civil & Environm Engn, Davis, CA 95616 USA. RP Hook, SJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM simon.j.hook@jpl.nasa.gov NR 34 TC 51 Z9 51 U1 2 U2 10 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 EI 1520-0426 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD APR PY 2003 VL 20 IS 4 BP 534 EP 548 DI 10.1175/1520-0426(2003)20<534:ROLBAS>2.0.CO;2 PG 15 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 665EX UT WOS:000182107600008 ER PT J AU Marshall, S Oglesby, RJ Nolin, AW AF Marshall, S Oglesby, RJ Nolin, AW TI The predictability of winter snow cover over the western United States SO JOURNAL OF CLIMATE LA English DT Article ID COMMUNITY-CLIMATE-MODEL; TELEMETRY SNOTEL DATA; NORTH-AMERICA; TEMPERATURE; VARIABILITY; HYDROLOGY; CCM3; ENSO AB A set of model runs was made with the National Center for Atmospheric Research (NCAR) Community Climate Model, version 3 (CCM3) to investigate and help assess the relative roles of snow cover anomalies and initial atmospheric states on the subsequent accumulation and ablation seasons. In order to elucidate the physical mechanisms responsible for the large impact in one case but small impact in the other, two experiments with CCM3 were made that imposed an exaggerated initial snow cover [1-m snow water equivalent (SWE)] over the western U. S. domain. One run was started on 1 December, the other on 1 February. These runs made it clear that the high albedo of snow was the dominant physical process. An additional set of runs with realistic yearly snow anomalies was also made. Results suggest that for runs starting in February (late winter), the initial prescription of snow cover is more important than the initial atmospheric state in determining the subsequent evolution of snow cover. For runs starting in December (early winter), the results are less clear, with neither the initial snow cover nor the initial state of the atmosphere appearing to be the dominant factor. In February, when the sun is relatively high in the sky and days are longer, the albedo effect is a dominant factor; while in December the sun was too low in the sky and days too short for the albedo effect to be important. As the winter season progressed, the subsequent accumulation of snow eliminated the effects of the initial December anomalies. C1 Univ N Carolina, Dept Geog & Earth Sci, Charlotte, NC 28223 USA. NASA, George C Marshall Space Flight Ctr, Natl Space Sci & Technol Ctr, Huntsville, AL 35812 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Marshall, S (reprint author), Univ N Carolina, Dept Geog & Earth Sci, 9201 Univ City Blvd, Charlotte, NC 28223 USA. EM susanm@uncc.edu NR 31 TC 7 Z9 8 U1 1 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD APR PY 2003 VL 16 IS 7 BP 1062 EP 1073 DI 10.1175/1520-0442(2003)016<1062:TPOWSC>2.0.CO;2 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 658JP UT WOS:000181718100004 ER PT J AU Antar, BN Paley, MS Witherow, WK AF Antar, BN Paley, MS Witherow, WK TI Experimental and numerical investigation of buoyancy driven convection during PDAMNA thin film growth SO JOURNAL OF CRYSTAL GROWTH LA English DT Article DE computer simulation; convection; heat transfer; microgravity conditions ID PHOTODEPOSITION AB This paper presents results from numerical simulations as well as laboratory experiments of buoyancy driven convection in an ampoule under varying heating and gravitational acceleration loadings. The modeling effort in this work resolves the large scale natural convective motion that occurs in the fluid during photodeposition of polydiacetelene films which is due to energy absorbed by the growth solution from a UV source. Consequently, the growth kinetics of the film are ignored in the model discussed here, and also a much simplified ampoule geometry is considered. The objective of this work is to validate the numerical prediction on the strength and structure of buoyancy driven convection that could occur under terrestrial conditions during nonlinear optical film growth. The validation is used to enable a reliable predictive capability on the nature and strength of the convective motion under low gravity conditions. The ampoule geometry is in the form of a parallelepiped with rectangular faces. The numerical results obtained from the solution to the Boussinesq equations show that natural convection will occur regardless of the orientation of the UV source with respect to the gravity vector. The least strong convective motion occurred with the UV beam directed at the top face of the parallelepiped. The strength of the convective motion was found to be almost linearly proportional to the total power of the UV source. Also, it was found that the strength of the convective motion decreased linearly with the gravity due to acceleration. The pattern of the convection flow on the other hand, depended on the source location. (C) 2003 Elsevier Science B.V. All rights reserved. C1 Univ Tennessee, Inst Space, Tullahoma, TN 37388 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Antar, BN (reprint author), Univ Tennessee, Inst Space, MS 26, Tullahoma, TN 37388 USA. NR 9 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD APR PY 2003 VL 250 IS 3-4 BP 565 EP 582 DI 10.1016/S0022-0248(02)02497-1 PG 18 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA 654VZ UT WOS:000181517900039 ER PT J AU Ruthruff, E Johnston, JC Van Selst, M Whitsell, S Remington, R AF Ruthruff, E Johnston, JC Van Selst, M Whitsell, S Remington, R TI Vanishing dual-task interference after practice: Has the bottleneck been eliminated or is it merely latent? SO JOURNAL OF EXPERIMENTAL PSYCHOLOGY-HUMAN PERCEPTION AND PERFORMANCE LA English DT Article ID RESPONSE SELECTION; PERFORMANCE; COMPATIBILITY; ATTENTION; TIME AB Practice can, in some cases, largely eliminate measured dual-task interference. Does this absence of interference indicate the absence of a processing bottleneck (defined as an inability to carry out certain stages in parallel)? The authors show that a bottleneck need not produce any observable interference, provided that there is no temporal overlap in the demand for bottleneck stages on the 2 tasks. Such a "latent" bottleneck is especially likely after practice, when central stages are short. The authors provide new evidence that a latent bottleneck occurred for a participant who produced no interference in M. Van Selst, E. Ruthruff, and J. C. Johnston (1999). These findings demonstrate that the absence of dual-task interference does not necessarily indicate the absence of a processing bottleneck. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. San Jose State Univ, Dept Psychol, San Jose, CA 95192 USA. RP Ruthruff, E (reprint author), NASA, Ames Res Ctr, Mailstop 262-4, Moffett Field, CA 94035 USA. NR 27 TC 77 Z9 77 U1 2 U2 7 PU AMER PSYCHOLOGICAL ASSOC PI WASHINGTON PA 750 FIRST ST NE, WASHINGTON, DC 20002-4242 USA SN 0096-1523 J9 J EXP PSYCHOL HUMAN JI J. Exp. Psychol.-Hum. Percept. Perform. PD APR PY 2003 VL 29 IS 2 BP 280 EP 289 DI 10.1037/0096-1523.29.2.280 PG 10 WC Psychology; Psychology, Experimental SC Psychology GA 675AG UT WOS:000182670400002 PM 12760615 ER PT J AU Freund, F AF Freund, F TI On the electrical conductivity structure of the stable continental crust SO JOURNAL OF GEODYNAMICS LA English DT Article ID NOMINALLY ANHYDROUS MINERALS; GRAIN-BOUNDARY GRAPHITE; MAGNESIUM-OXIDE; SINGLE-CRYSTAL; LABORATORY MEASUREMENTS; ELECTROMAGNETIC INDUCTION; CHARGE-DISTRIBUTION; METAMORPHIC ROCKS; AQUEOUS FLUIDS; EARTHS MANTLE AB A high conductivity zone (HCZ) exists in many places worldwide in the stable rnid- to lower continental crust, at the depth of about 20-30 km, but its origin is enigmatic. At this depth range, the temperatures are constrained between 400 and 600 degreesC and free fluids are believed to have been consumed by retrograde mineral reactions. Many causes for the HCZ have been considered such as residual fluids and brines, partial melting, serpentine or other hydroxyl-bearing minerals in a state of dehydration, but intergranular carbon films have been the most widely accepted explanation. This view is challenged. Electrical conductivity and dielectric polarization measurements on materials as structurally and chemically diverse as laboratory-grown MgO, upper mantle olivine single crystals, and lower crustal anorthosite rock indicate that, in all of them, highly mobile electronic charge carriers are generated in the 450+/-50-650+/-50 degreesC window. These charge carriers are positive holes, e.g. defect electrons in the O 2p-dominated valence band, chemically equivalent to O- in the O2- matrix. They form through dissociation of positive hole pairs, PHP, chemically equivalent to peroxy links, O3X-OO-XO3 (X = Si4+, Al3+ etc.). The PHPs in turn derive from hydroxyl, O3X-OH, that become incorporated into nominally anhydrous minerals whenever they crystallize in H2O-laden magmatic or metamorphic environments. Upon cooling, O3X-OH pairs undergo a redox conversion to O3X-OO-XO3 plus H-2. Positive hole charge carriers have no problem co-existing with reduced cations under the non-equilibrium conditions that prevail in dry rocks below 600 degreesC and they dominate their electrical conductivity in the 400-600 degreesC temperature range. It is proposed that the HCZ is caused by positive hole charge carriers that are metastably activated in the crust in the 20-30 km depth range. (C) 2002 Elsevier Science Ltd, All rights reserved. C1 San Jose State Univ, Dept Phys, Moffett Field, CA 94035 USA. NASA, Ames Res Ctr, SETI Inst, Moffett Field, CA 94035 USA. RP San Jose State Univ, Dept Phys, MS 239-20, Moffett Field, CA 94035 USA. EM ffreund@mail.arc.nasa.gov NR 97 TC 35 Z9 42 U1 3 U2 15 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0264-3707 J9 J GEODYN JI J. Geodyn. PD APR PY 2003 VL 35 IS 3 BP 353 EP 388 AR PII S0264-3707(02)00154-0 DI 10.1016/S0264-3707(02)00154-0 PG 36 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 642HY UT WOS:000180799200006 ER PT J AU Luo, LF Robock, A Vinnikov, KY Schlosser, CA Slater, AG Boone, A Braden, H Cox, P de Rosnay, P Dickinson, RE Dai, YJ Duan, QY Etchevers, P Henderson-Sellers, A Gedney, N Gusev, YM Habets, F Kim, JW Kowalczyk, E Mitchell, K Nasonova, ON Noilhan, J Pitman, AJ Schaake, J Shmakin, AB Smirnova, TG Wetzel, P Xue, YK Yang, ZL Zeng, QC AF Luo, LF Robock, A Vinnikov, KY Schlosser, CA Slater, AG Boone, A Braden, H Cox, P de Rosnay, P Dickinson, RE Dai, YJ Duan, QY Etchevers, P Henderson-Sellers, A Gedney, N Gusev, YM Habets, F Kim, JW Kowalczyk, E Mitchell, K Nasonova, ON Noilhan, J Pitman, AJ Schaake, J Shmakin, AB Smirnova, TG Wetzel, P Xue, YK Yang, ZL Zeng, QC TI Effects of frozen soil on soil temperature, spring infiltration, and runoff: Results from the PILPS 2(d) experiment at Valdai, Russia SO JOURNAL OF HYDROMETEOROLOGY LA English DT Article ID LAND-SURFACE SCHEME; MOISTURE SIMULATIONS; SNOW-COVER; MODEL; PARAMETERIZATION; CLIMATE; BIOSPHERE; REPRESENTATION; VALIDATION; HYDROLOGY AB The Project for Intercomparison of Land-Surface Parameterization Schemes phase 2(d) experiment at Valdai, Russia, offers a unique opportunity to evaluate land surface schemes, especially snow and frozen soil parameterizations. Here, the ability of the 21 schemes that participated in the experiment to correctly simulate the thermal and hydrological properties of the soil on several different timescales was examined. Using observed vertical profiles of soil temperature and soil moisture, the impact of frozen soil schemes in the land surface models on the soil temperature and soil moisture simulations was evaluated. It was found that when soil-water freezing is explicitly included in a model, it improves the simulation of soil temperature and its variability at seasonal and interannual scales. Although change of thermal conductivity of the soil also affects soil temperature simulation, this effect is rather weak. The impact of frozen soil on soil moisture is inconclusive in this experiment due to the particular climate at Valdai, where the top 1 m of soil is very close to saturation during winter and the range for soil moisture changes at the time of snowmelt is very limited. The results also imply that inclusion of explicit snow processes in the models would contribute to substantially improved simulations. More sophisticated snow models based on snow physics tend to produce better snow simulations, especially of snow ablation. Hysteresis of snow-cover fraction as a function of snow depth is observed at the catchment but not in any of the models. C1 Rutgers State Univ, Dept Environm Sci, New Brunswick, NJ 08901 USA. Univ Maryland, Dept Meteorol, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Goddard Earth Sci & Technol Ctr, Greenbelt, MD 20771 USA. Univ Colorado, CIRES, Boulder, CO 80309 USA. Meteo France CNRM, Toulouse, France. German Weather Serv, Agrommeteorol Res, Braunschweig, Germany. Hadley Ctr Climate Predict & Res, Bracknell, Berks, England. CNRS, Lab Meteorol Dynam, Paris, France. Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. Chinese Acad Sci, Inst Atmospher Phys, Beijing, Peoples R China. NOAA, Off Hydrol, Silver Spring, MD USA. Australian Nucl Sci & Technol Org, Sydney, NSW, Australia. Univ Reading, Dept Meteorol, Reading, Berks, England. Russian Acad Sci, Inst Water Problems, Moscow, Russia. Univ Calif Los Angeles, Dept Atmospher Sci, Los Angeles, CA 90024 USA. CSIRO, Div Atmospher Res, Aspendale, Vic 3195, Australia. NOAA NCEP, Environm Modeling Ctr, Camp Springs, MD USA. Macquarie Univ, Dept Phys Geog, Sydney, NSW 2109, Australia. Russian Acad Sci, Inst Geog, Moscow, Russia. NOAA, Forecast Syst Lab, Boulder, CO USA. NASA, Goddard Space Flight Ctr, Mesoscale Dynam & Precipitat Branch, Greenbelt, MD 20771 USA. Univ Calif Los Angeles, Dept Geog, Los Angeles, CA 90024 USA. Univ Texas, Dept Geol Sci, Austin, TX USA. RP Robock, A (reprint author), Rutgers State Univ, Dept Environm Sci, 14 Coll Farm Rd, New Brunswick, NJ 08901 USA. EM robock@envsci.rutgers.edu RI Cox, Peter/B-3299-2012; Dai, Yongjiu/D-6261-2014; Slater, Andrew/B-4666-2008; Luo, Lifeng/C-8734-2009; Vinnikov, Konstantin/F-9348-2010; Dai, Yongjiu/D-1070-2010; Yang, Zong-Liang/B-4916-2011; Pitman, Andrew/A-7353-2011; Henderson-Sellers, Ann/H-5323-2011; de Rosnay, Patricia/M-8203-2013; Nasonova, Olga/B-6093-2014; Duan, Qingyun/C-7652-2011; gusev, yugeniy/G-4711-2014; Smirnova, Tatiana/D-3350-2015; Robock, Alan/B-6385-2016 OI Dai, Yongjiu/0000-0002-3588-6644; SLATER, ANDREW/0000-0002-4009-4844; Slater, Andrew/0000-0003-0480-8560; Habets, Florence/0000-0003-1950-0921; Robock, Alan/0000-0002-6319-5656; Pitman, Andrew/0000-0003-0604-3274; de Rosnay, Patricia/0000-0002-7374-3820; Duan, Qingyun/0000-0001-9955-1512; gusev, yugeniy/0000-0003-3886-2143; NR 39 TC 90 Z9 103 U1 1 U2 31 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 1525-755X EI 1525-7541 J9 J HYDROMETEOROL JI J. Hydrometeorol. PD APR PY 2003 VL 4 IS 2 BP 334 EP 351 DI 10.1175/1525-7541(2003)4<334:EOFSOS>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 668EF UT WOS:000182276800013 ER PT J AU Koster, RD Suarez, MJ AF Koster, RD Suarez, MJ TI Impact of land surface initialization on seasonal precipitation and temperature prediction SO JOURNAL OF HYDROMETEOROLOGY LA English DT Article ID GENERAL-CIRCULATION MODELS; SOIL-MOISTURE ANOMALIES; UNITED-STATES; CLIMATE MODEL; NORTH-AMERICA; JULY 1993; PREDICTABILITY; VARIABILITY; ATMOSPHERE; DROUGHT AB The potential role of land initialization in seasonal forecasting is illustrated through ensembles of simulations with the NASA Seasonal-to-Interannual Prediction Project (NSIPP) model. For each boreal summer during 1997 2001, two 16-member ensembles of 3-month simulations were generated. The first, "AMIP style'' ( Atmospheric Model Intercomparison Project) ensemble establishes the degree to which a perfect prediction of SSTs would contribute to the seasonal prediction of precipitation and temperature over continents. The second ensemble is identical to the first, except that the land surface is also initialized with "realistic'' soil moisture contents through the continuous prior application (within GCM simulations leading up to the start of the forecast period) of a daily observational precipitation dataset and the associated avoidance of model drift through the scaling of all surface prognostic variables. A comparison of the two ensembles shows that land initialization has a statistically significant impact on summertime precipitation over only a handful of continental regions. These regions agree, to first order, with those that satisfy three conditions: 1) a tendency toward large initial soil moisture anomalies, 2) a strong sensitivity of evaporation to soil moisture, and 3) a strong sensitivity of precipitation to evaporation. The impact on temperature prediction is more spatially extensive. The degree to which the initialization increases the skill of the forecasts is mixed, reflecting a critical need for the continued development of model parameterizations and data analysis strategies. C1 NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Climate & Radiat Branch, Atmospheres Lab, Greenbelt, MD 20771 USA. RP Koster, RD (reprint author), NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Lab Hydrospher Proc, Code 974, Greenbelt, MD 20771 USA. RI Koster, Randal/F-5881-2012 OI Koster, Randal/0000-0001-6418-6383 NR 41 TC 77 Z9 77 U1 2 U2 6 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 APR PY 2003 VL 4 IS 2 BP 408 EP 423 DI 10.1175/1525-7541(2003)4<408:IOLSIO>2.0.CO;2 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 668EF UT WOS:000182276800017 ER PT J AU Keppenne, CL Rienecker, MM AF Keppenne, CL Rienecker, MM TI Assimilation of temperature into an isopycnal ocean general circulation model using a parallel ensemble Kalman filter SO JOURNAL OF MARINE SYSTEMS LA English DT Article; Proceedings Paper CT 33rd International Liege Colloquium on Ocean Dynamics CY MAY 07-11, 2001 CL LIEGE, BELGIUM DE temperature; ocean general circulation model; ensemble Kalman filter ID PACIFIC-OCEAN; EL-NINO AB Temperature data from the Tropical Atmosphere and Ocean (TAO) array are assimilated into the Pacific basin configuration of the Poseidon quasi-isopycnal ocean general circulation model (OGCM) using a multivariate ensemble Kalman filter (EnKF) implemented on a massively parallel computer architecture. An assimilation algorithm whereby each processing element (PE) solves a localized analysis problem is used. The algorithm relies on a locally supported error-covariance model to avoid the introduction of spurious long-range covariances associated with small ensemble sizes and to facilitate its efficient parallel implementation on a computing platform with distributed memory. Each time data are assimilated, multivariate background-error statistics estimated from the phase-space distribution of an ensemble of model states are used to calculate the Kalman gain matrix and the analysis increments. The resulting cross-field covariances are used to compute temperature, salinity and current increments. The layer thicknesses are left unchanged by the analysis. Instead, they are dynamically adjusted by the model between successive analyses. Independent acoustic Doppler current profiler data are used to assess the performance of the temperature data assimilation. The temperature analyses are also compared to analyses obtained with a univariate optimal interpolation (UOI) algorithm and to a control run without temperature assimilation. The results demonstrate that the multivariate EnKF is both practical and effective for assimilating in situ and remotely sensed observations into a high resolution ocean model in a quasi-operational framework. (C) 2003 Published by Elsevier Science B.V. C1 NASA, Goddard Space Flight Ctr, Seasonal Interannual Predict Project, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. Sci Applicat Int Corp, Beltsville, MD 20705 USA. RP Keppenne, CL (reprint author), NASA, Goddard Space Flight Ctr, Seasonal Interannual Predict Project, Lab Hydrospher Proc, Mail Code 971, Greenbelt, MD 20771 USA. EM keppenne@gsfc.nasa.gov NR 24 TC 30 Z9 35 U1 3 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0924-7963 J9 J MARINE SYST JI J. Mar. Syst. PD APR PY 2003 VL 40 BP 363 EP 380 DI 10.1016/S0924-7963(03)00025-3 PG 18 WC Geosciences, Multidisciplinary; Marine & Freshwater Biology; Oceanography SC Geology; Marine & Freshwater Biology; Oceanography GA 674EW UT WOS:000182625300016 ER PT J AU Toth, RA Brown, LR AF Toth, RA Brown, LR TI Oxygen broadening parameters of water vapor: 1212-2136 cm(-1) SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article ID H2O LINES; TEMPERATURE; AIR; TRANSITION; NITROGEN; REGION; ARGON AB Oxygen-broadened half-widths and pressure induced frequency shifts of water vapor were measured in the (0 1 0)-(0 0 0) band between 1212 and 2136 cm(-1). Over 400 observations were obtained at 0.0054 cm(-1) spectral resolution using a Fourier transform spectrometer at the Kitt Peak National Observatory. The observed width coefficients ranged from 0.0057 to 0.0718 cm(-1)/atm and the shift coefficients fell between 0.0042 and -0.0169 cm(-1)/atm. Previous measurements of N-2- and air-broadening of H2O by the first author over this spectral range were included in the analysis to compute air-broadening coefficients with comparisons to the observed values. The H2O + O-2 measured half-widths are compared with previously measured values given in the available literature. (C) 2003 Elsevier Science (USA). All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Toth, RA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 183-301, Pasadena, CA 91109 USA. NR 13 TC 8 Z9 8 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 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD APR PY 2003 VL 218 IS 2 BP 135 EP 150 DI 10.1016/S0022-2852(02)00022-X PG 16 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 673YV UT WOS:000182609600001 ER PT J AU Toth, RA Brown, LR Cohen, EA AF Toth, RA Brown, LR Cohen, EA TI Linestrengths of nitric acid from 850 to 920 cm(-1) SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article DE nitric acid; line parameters; intensities; high resolution spectroscopy ID BAND INTENSITIES; LINE-INTENSITIES; 2-NU(9) BANDS; HNO3; SPECTRUM; 2-NU-9; NU(5); N2O5; NU-5 AB Several thousand line positions and strengths of HNO3 in the 850-920 cm(-1) region were retrieved from spectra at low sample pressures at 299 K and high spectral resolution (0.0027 cm(-1)) using the McMath-Pierce Fourier transform spectrometer (FTS) at the National Solar Observatory located at Kitt Peak, AZ. Of these, 733 linestrengths of the nu(5) band and 402 lines of the 2(nu9) band were measured with precisions of 10% or better. In addition, over 800 features with no assignments and 8-15% uncertainties in the linestrengths were obtained. The measured linestrengths of nu(5) and 2(v9) were compared to prior measurements and to the values given in the 2000 HITRAN compilation. The average ratios of HITRAN/present was found to be 1.14 +/- 0.06, but the relative band intensities of the fundamental and overtone were in agreement with the calculated values. The intensities of strong absorptions in the Q branch of the nu(5) + nu(9) - nu(9) band (between 885.418 and 885.437 cm(-1)) were within 4% of the 2000 HITRAN values, although there was an offset in the positions. The analysis of these data was greatly hindered by the high density of transitions and the lack of knowledge about other hot bands in the region. (C) 2003 Elsevier Science (USA). All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Toth, RA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 183-301, Pasadena, CA 91109 USA. NR 22 TC 10 Z9 10 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 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD APR PY 2003 VL 218 IS 2 BP 151 EP 168 DI 10.1016/S0022-2852(02)00023-1 PG 18 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 673YV UT WOS:000182609600002 ER PT J AU Jacob, SD Shay, LK AF Jacob, SD Shay, LK TI The role of oceanic mesoscale features on the tropical cyclone-induced mixed layer response: A case study SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID NUMERICAL SIMULATIONS; HURRICANE-GILBERT; MODEL; THERMOCLINE; VELOCITY; MEXICO; RINGS; STORM; GULF AB Oceanic mixed layer (ML) response to Hurricane Gilbert in the western Gulf of Mexico is investigated in this paper using the Miami Isopycnic Coordinate Ocean Model (MICOM). Three snapshots of oceanic observations indicated that a Loop Current Warm Core Eddy (LCWCE) contributed significantly to the ML heat and mass budgets. To examine the time evolution of different physical processes in the ML, MICOM is initialized with realistic, climatological, and quiescent conditions for the same realistic forcing. The ML evolves differently for the realistic background condition with the LCWCE in the domain; differences between climatological and quiescent conditions remain small. Mixed layer temperature (MLT) and ML depth (MLD) differences of up to 1degreesC and 30 m are directly attributed to horizontal advective processes in the LCWCE regime due to preexisting velocities. Comparison of simulated temperatures using realistic conditions in the model shows improved agreement with profiler observations. Using four entrainment mixing parameterizations, the spatial and temporal ML evolution is investigated in MICOM simulations. Although the rates of simulated cooling and deepening differ for the four schemes, the overall pattern remains qualitatively similar. For the three schemes that use surface-induced turbulence to predict entrainment rate, the cooling pattern extends farther away from the track. Based on linear regression analysis, MLTs simulated using the bulk Richardson number closure fit the observed temperatures better than did the other schemes. Averaged surface fluxes ranged from 10% to 30% in the directly forced region, with larger values in the LCWCE regime. Overall, entrainment mixing remains the dominant mechanism in controlling the heat and mass budgets. C1 Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Div Meteorol & Phys Oceanog, Miami, FL 33149 USA. RP Jacob, SD (reprint author), Univ Maryland Baltimore Cty, GEST Ctr, NASA, Goddard Space Flight Ctr, Code 971, Greenbelt, MD 20771 USA. NR 30 TC 55 Z9 55 U1 1 U2 7 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-3670 J9 J PHYS OCEANOGR JI J. Phys. Oceanogr. PD APR PY 2003 VL 33 IS 4 BP 649 EP 676 DI 10.1175/1520-0485(2003)33<649:TROOMF>2.0.CO;2 PG 28 WC Oceanography SC Oceanography GA 660UC UT WOS:000181851100002 ER PT J AU Egbert, GD Ray, RD AF Egbert, GD Ray, RD TI Deviation of long-period tides from equilibrium: Kinematics and geostrophy SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID GEOSAT ALTIMETRY; GLOBAL OCEAN; PRESSURE; TOPOGRAPHY; WAVES AB New empirical estimates of the long-period fortnightly (Mf) tide obtained from TOPEX/Poseidon (T/P) altimeter data confirm significant basin-scale deviations from equilibrium. Elevations in the low-latitude Pacific have reduced amplitude and lag those in the Atlantic by 30degrees or more. These interbasin amplitude and phase variations are robust features that are reproduced by numerical solutions of the shallow-water equations, even for a constant-depth ocean with schematic interconnected rectangular basins. A simplified analytical model for cooscillating connected basins also reproduces the principal features observed in the empirical solutions. This simple model is largely kinematic. Zonally averaged elevations within a simple closed basin would be nearly in equilibrium with the gravitational potential, except for a constant offset required to conserve mass. With connected basins these offsets are mostly eliminated by interbasin mass flux. Because of rotation, this flux occurs mostly in a narrow boundary layer across the mouth and at the western edge of each basin, and geostrophic balance in this zone supports small residual offsets (and phase shifts) between basins. The simple model predicts that this effect should decrease roughly linearly with frequency, a result that is confirmed by numerical modeling and empirical T/P estimates of the monthly (Mm) tidal constituent. This model also explains some aspects of the anomalous nonisostatic response of the ocean to atmospheric pressure forcing at periods of around 5 days. C1 Oregon State Univ, Coll Ocean & Atmospher Sci, Corvallis, OR 97331 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Egbert, GD (reprint author), Oregon State Univ, Coll Ocean & Atmospher Sci, Ocean Adm Bldg 104, Corvallis, OR 97331 USA. RI Ray, Richard/D-1034-2012; OI Egbert, Gary/0000-0003-1276-8538 NR 34 TC 28 Z9 28 U1 0 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-3670 J9 J PHYS OCEANOGR JI J. Phys. Oceanogr. PD APR PY 2003 VL 33 IS 4 BP 822 EP 839 DI 10.1175/1520-0485(2003)33<822:DOLTFE>2.0.CO;2 PG 18 WC Oceanography SC Oceanography GA 660UC UT WOS:000181851100010 ER PT J AU Chernov, AA AF Chernov, AA TI Protein crystals and their growth SO JOURNAL OF STRUCTURAL BIOLOGY LA English DT Article DE proteins; crystals; crystallization; kinetics; solubility; defects; structural resolution; microgravity ID LIGHT-SCATTERING INVESTIGATIONS; 2ND VIRIAL-COEFFICIENT; LYSOZYME CRYSTALS; DEFECT FORMATION; CRYSTALLIZATION; SOLUBILITY; IMPURITIES; NUCLEATION; MECHANISMS; FERRITIN AB Recent results on the associations between protein molecules in crystal lattices, crystal-solution surface energy, elastic properties, strength, and spontaneous crystal cracking are reviewed and discussed. In addition, some basic approaches to understanding the solubility of proteins are followed by an overview of crystal nucleation and growth. It is argued that variability of mixing in batch crystallization may be a source of the variation in the number of crystals ultimately appearing in the sample. The frequency at which new molecules join a crystal lattice is measured by the kinetic coefficient and is related to the observed crystal growth rate. Numerical criteria used to discriminate diffusion- and kinetic-limited growth are discussed on this basis. Finally, the creation of defects is discussed with an emphasis on the role of impurities and convection on macromolecular crystal perfection. (C) 2003 Published by Elsevier Science (USA). C1 NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, Huntsville, AL 35812 USA. RP Chernov, AA (reprint author), NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, Mail Code SD46, Huntsville, AL 35812 USA. NR 68 TC 96 Z9 98 U1 2 U2 27 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 APR PY 2003 VL 142 IS 1 BP 3 EP 21 DI 10.1016/S1047-8477(03)00034-0 PG 19 WC Biochemistry & Molecular Biology; Biophysics; Cell Biology SC Biochemistry & Molecular Biology; Biophysics; Cell Biology GA 675TJ UT WOS:000182711400002 PM 12718915 ER PT J AU Golden, BL Kundrot, CE AF Golden, BL Kundrot, CE TI RNA crystallization SO JOURNAL OF STRUCTURAL BIOLOGY LA English DT Article ID PHENYLALANINE TRANSFER-RNA; SPARSE-MATRIX APPROACH; HAMMERHEAD RIBOZYME; PROTEIN CRYSTALLIZATION; TETRAHYMENA RIBOZYME; GENERAL-PRINCIPLES; CRYSTAL-STRUCTURE; POLYMERASE; SEQUENCE; INVITRO AB RNA molecules may be crystallized using variations of the methods developed for protein crystallography. As the technology has become available to synthesize and purify RNA molecules in the quantities and with the quality that is required for crystallography, the field of RNA structure has exploded. The first consideration when crystallizing an RNA is the sequence, which may be varied in a rational way to enhance crystallizability or prevent formation of alternate structures. Once a sequence has been designed, the RNA may be synthesized chemically by solid-state synthesis or it may be produced enzymatically using RNA polymerase and an appropriate DNA template. Purification of milligram quantities of RNA can be accomplished by HPLC or gel electrophoresis. As with proteins, crystallization of RNA is usually accomplished by vapor diffusion techniques. There are several considerations that are either unique to RNA crystallization or more important for RNA crystallization. Techniques for design, synthesis, purification, and crystallization of RNAs will be reviewed here. (C) 2003 Published by Elsevier Science (USA). C1 NASA, George C Marshall Space Flight Ctr, Struct Biol Lab, Huntsville, AL 35812 USA. Purdue Univ, Dept Biochem, W Lafayette, IN 47907 USA. RP NASA, George C Marshall Space Flight Ctr, Struct Biol Lab, Mail Code SD48, Huntsville, AL 35812 USA. EM craig.e.kundrot@nasa.gov OI Golden, Barbara/0000-0002-9741-882X NR 39 TC 20 Z9 21 U1 2 U2 5 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 1047-8477 EI 1095-8657 J9 J STRUCT BIOL JI J. Struct. Biol. PD APR PY 2003 VL 142 IS 1 BP 98 EP 107 DI 10.1016/S1047-8477(03)00042-X PG 10 WC Biochemistry & Molecular Biology; Biophysics; Cell Biology SC Biochemistry & Molecular Biology; Biophysics; Cell Biology GA 675TJ UT WOS:000182711400010 PM 12718923 ER PT J AU van der Woerd, M Ferree, D Pusey, M AF van der Woerd, M Ferree, D Pusey, M TI The promise of macromolecular crystallization in microfluidic chips SO JOURNAL OF STRUCTURAL BIOLOGY LA English DT Article DE macromolecule crystallization; microfluidics; lab on a chip ID PROTEIN CRYSTAL-GROWTH; ON-A-CHIP; STRUCTURAL GENOMICS; ELECTRON-DENSITY; CRYSTALLOGRAPHY; SOLUBILITY; SEQUENCE; DEVICES AB Microfluidics, or lab-on-a-chip technology, is proving to be a powerful, rapid, and efficient approach to a wide variety of bioanalytical and microscale biopreparative needs. The low materials consumption, combined with the potential for packing a large number of experiments in a few cubic centimeters, makes it an attractive technique for both initial screening and subsequent optimization of macromolecular crystallization conditions. Screening operations, which require a macromolecule solution with a standard set of premixed solutions, are relatively straightforward and have been successfully demonstrated in a microfluidics platform. Optimization methods, in which crystallization solutions are independently formulated from a range of stock solutions, are considerably more complex and have yet to be demonstrated. To be competitive with either approach, a microfluidics system must offer ease of operation, be able to maintain a sealed environment over several weeks to months, and give ready access for the observation and harvesting of crystals as they are grown. (C) 2003 Published by Elsevier Science (USA). C1 NASA, George C Marshall Space Flight Ctr, Biophys SD46, Huntsville, AL 35812 USA. NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, Huntsville, AL 35812 USA. RP Pusey, M (reprint author), NASA, George C Marshall Space Flight Ctr, Biophys SD46, Mail Code SK46, Huntsville, AL 35812 USA. EM Marc.pusey@msfc.nasa.gov NR 27 TC 33 Z9 33 U1 1 U2 10 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 APR PY 2003 VL 142 IS 1 BP 180 EP 187 DI 10.1016/S1047-8477(03)00049-2 PG 8 WC Biochemistry & Molecular Biology; Biophysics; Cell Biology SC Biochemistry & Molecular Biology; Biophysics; Cell Biology GA 675TJ UT WOS:000182711400017 PM 12718930 ER PT J AU Shuster, MD Markley, FL AF Shuster, MD Markley, FL TI Generalization of the Euler angles SO JOURNAL OF THE ASTRONAUTICAL SCIENCES LA English DT Article AB It is shown that the Euler angles can be generalized to axes other than members of an orthnormal triad. As first shown by Davenport, the three generalized Euler axes, hereafter: Davenport axes, must still satisfy the constraint that the first two and the last two axes be mutually perpendicular if these axes are to define a universal set of attitude parameters. Expressions are given which relate the generalized Euler angles, hereafter: Davenport angles, to the 3-1-3 Euler angles of an associated direction-cosine matrix. The computation of the Davenport angles from the attitude matrix and their kinematic equation are presented. The present work offers a more direct development of the Davenport angles than Davenport's original publication and offers additional results. C1 Acme Spacecraft Co, Germantown, MD 20874 USA. NASA, Goddard Space Flight Ctr, Guidance Navigat & Control Syst Engn Branch, Greenbelt, MD 20771 USA. RP Shuster, MD (reprint author), Acme Spacecraft Co, 13017 Wisteria Dr,Box 328, Germantown, MD 20874 USA. EM m.shuster@ieee.org; landis.markley@nasa.gov NR 7 TC 13 Z9 13 U1 1 U2 1 PU AMER ASTRONAUTICAL SOC PI SPRINGFIELD PA 6352 ROLLING MILL PLACE SUITE 102, SPRINGFIELD, VA 22152 USA SN 0021-9142 J9 J ASTRONAUT SCI JI J. Astronaut. Sci. PD APR-JUN PY 2003 VL 51 IS 2 BP 123 EP 132 PG 10 WC Engineering, Aerospace SC Engineering GA 807UF UT WOS:000220525700001 ER PT J AU Sassen, K Arnott, WP Starr, DO Mace, GG Wang, Z Poellot, MR AF Sassen, K Arnott, WP Starr, DO Mace, GG Wang, Z Poellot, MR TI Midlatitude cirrus clouds derived from Hurricane Nora: A case study with implications for ice crystal nucleation and shape SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID RADIATIVE PROPERTIES; AEROSOL-PARTICLES; SEA-SALT; PART I; LIDAR; FACILITY; CLIMATOLOGY; RETRIEVAL; DROPLETS; SULFATE AB Hurricane Nora traveled up the Baja Peninsula coast in the unusually warm El Nino waters of September 1997 until rapidly decaying as it approached southern California on 24 September. The anvil cirrus blowoff from the final surge of tropical convection became embedded in subtropical flow that advected the cirrus across the western United States, where it was studied from the Facility for Atmospheric Remote Sensing (FARS) in Salt Lake City, Utah, on 25 September. A day later, the cirrus shield remnants were redirected southward by midlatitude circulations into the southern Great Plains, providing a case study opportunity for the research aircraft and ground-based remote sensors assembled at the Clouds and Radiation Testbed (CART) site in northern Oklahoma. Using these comprehensive resources and new remote sensing cloud retrieval algorithms, the microphysical and radiative cloud properties of this unusual cirrus event are uniquely characterized. Importantly, at both the FARS and CART sites the cirrus generated spectacular halos and arcs, which acted as a tracer for the hurricane cirrus, despite the limited lifetimes of individual ice crystals. Lidar depolarization data indicate widespread regions of uniform ice plate orientations, and in situ particle replicator data show a preponderance of pristine, solid hexagonal plates and columns. It is suggested that these unusual aspects are the result of the mode of cirrus particle nucleation, presumably involving the lofting of sea salt nuclei in strong thunderstorm updrafts into the upper troposphere. This created a reservoir of haze particles that continued to produce halide-salt-contaminated ice crystals during the extended period of cirrus cloud maintenance. The inference that marine microbiota are embedded in the replicas of some ice crystals collected over the CART site points to the longevity of marine effects. Various nucleation scenarios proposed for cirrus clouds based on this and other studies, and the implications for understanding cirrus radiative properties on a global scale, are discussed. C1 Univ Alaska, Inst Geophys, Fairbanks, AK 99775 USA. Univ Nevada, Desert Res Inst, Reno, NV 89506 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Utah, Dept Meteorol, Salt Lake City, UT 84112 USA. Univ Maryland, Baltimore, MD 21201 USA. Univ N Dakota, Dept Atmospher Sci, Grand Forks, ND 58201 USA. RP Sassen, K (reprint author), Univ Alaska, Inst Geophys, POB 757320, Fairbanks, AK 99775 USA. EM ksassen@gi.alaska.edu RI Wang, Zhien/F-4857-2011 NR 44 TC 17 Z9 17 U1 0 U2 12 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD APR PY 2003 VL 60 IS 7 BP 873 EP 891 DI 10.1175/1520-0469(2003)060<0873:MCCDFH>2.0.CO;2 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 657MR UT WOS:000181671400001 ER PT J AU Kizito, JP Alexander, JID Banish, RM AF Kizito, JP Alexander, JID Banish, RM TI Transient convective effects on diffusion measurements in liquids SO JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER LA English DT Article ID CRYSTAL-GROWTH; SOLIDIFICATION AB The transient effects of connective disturbances on self-diffusivity measurements are evaluated using numerical simulations. "Codastefano-type" diffusivity measurements, where continuous real-time measurements of the concentration of the diffusing species are made at two discrete locations using a radioactive tracer, are considered. Convection arises due to buoyancy caused by the interaction of temperature gradients with either gravity (terrestrial experiments) or residual acceleration (microgravity experiments). For small deviations from ideal isothermal conditions, the system's response to residual microgravity disturbances is examined. The consequences of heating and cooling "temperature ramps" are also examined for both microgravity and terrestrial conditions. The frequency, amplitude, and orientation of the residual acceleration vector and the magnitude of heating or cooling rates all affect the fidelity of a given measurement. It is also shown that, for actual high-temperature experiments, it is important to assess the degree of isothermality that can be attained. C1 Case Western Reserve Univ, Natl Ctr Micrograv Res Fluids & Combust, NASA, John H Glenn Res Ctr, Cleveland, OH 44106 USA. Case Western Reserve Univ, Dept Mech & Aerosp Engn, Cleveland, OH 44106 USA. Univ Alabama, Ctr Micrograv & Mat Res, Huntsville, AL 35899 USA. RP Kizito, JP (reprint author), Case Western Reserve Univ, Natl Ctr Micrograv Res Fluids & Combust, NASA, John H Glenn Res Ctr, Cleveland, OH 44106 USA. NR 18 TC 2 Z9 2 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0887-8722 J9 J THERMOPHYS HEAT TR JI J. Thermophys. Heat Transf. PD APR-JUN PY 2003 VL 17 IS 2 BP 186 EP 192 DI 10.2514/2.6775 PG 7 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA 667DK UT WOS:000182215500009 ER PT J AU Li, K Li, BQ de Groh, HC AF Li, K Li, BQ de Groh, HC TI Numerical analysis of double-diffusive convection/solidification under g-jitter/magnetic fields SO JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER LA English DT Article ID SEMICONDUCTOR CRYSTAL-GROWTH; G-JITTER; MAGNETIC-FIELDS; CONVECTION; MICROGRAVITY; SOLIDIFICATION; ACCELERATIONS AB A finite element model is presented for the g-fitter induced double-diffusive convection and solidification phenomena with and without the presence of magnetic fields in an Sn-doped Bi crystal growth system planned for space experiments. The model is developed based on the deforming finite element formulation with the penalty formulation for pressure approximation. An isothermal front tracking algorithm is used to predict the solid-liquid interface. Extensive numerical simulations are carried out and parameters studied include the solute concentration dependent melting temperature and magnetic field strength under both steady state and g-fitter conditions. Both synthesized g-fitter and real g-fitter data taken from space flights are used. Computed results show that the concentration effects on interface morphology must be considered for an accurate prediction of solidification interface morphology, and g-fitter can induce significant connective flows in the liquid pool, which, in turn, cause solute concentration nonuniformity during the space crystal growth. The use of an applied magnetic field can be effective in suppressing the deleterious g-fitter induced convection and solute nonuniformity and their effects on solidification. C1 Washington State Univ, Sch Mech & Mat Engn, Pullman, WA 99164 USA. NASA, John H Glenn Res Ctr, Cleveland, OH 44135 USA. RP Li, K (reprint author), Washington State Univ, Sch Mech & Mat Engn, Pullman, WA 99164 USA. NR 20 TC 10 Z9 10 U1 0 U2 4 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0887-8722 J9 J THERMOPHYS HEAT TR JI J. Thermophys. Heat Transf. PD APR-JUN PY 2003 VL 17 IS 2 BP 199 EP 209 PG 11 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA 667DK UT WOS:000182215500011 ER PT J AU Wang, TS Rhodes, R AF Wang, TS Rhodes, R TI Thermophysics characterization of multiply ionized air plasma absorption of laser radiation SO JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER LA English DT Article; Proceedings Paper CT AIAA 33rd Plasmadynamics and Lasers Conference CY MAY 20-23, 2002 CL MAUI, HAWAII SP AIAA ID PERFORMANCE; LIGHTCRAFT; PROPULSION AB Thermodynamic properties of multiply ionized air plasma atoms are computed using hydrogenic approtimation of the electronic partition function for temperatures up to 1,500,000 K, to study the impact of multiple ionization of air plasma on the inverse Bremsstrahlung absorption of laser radiation. Three formulas of inverse Bremsstrahlung absorption are investigated, and a general electron-ion inverse Bremsstrahlung formula is derived for multispecies, multiple ionization absorption. The computed double ionization absorption coefficients agree reasonably well with those of literature for 1, 10, and 100 atm. The importance of multiple ionization modeling is demonstrated by finding that the area under the full ionization absorption curve is twice that of single ionization. The effect of pressure on fully ionized air plasma absorption is computed for five pressures: 0.01, 0.1, 1, 10, and 100 atm. C1 NASA, George C Marshall Space Flight Ctr, Appl Fluid Dynam Anal Grp, Space Transportat Directorate, Huntsville, AL 35812 USA. Univ Tennessee, Inst Space, Ctr Laser Applicat, Tullahoma, TN 37388 USA. RP Wang, TS (reprint author), NASA, George C Marshall Space Flight Ctr, Appl Fluid Dynam Anal Grp, Space Transportat Directorate, Huntsville, AL 35812 USA. NR 27 TC 5 Z9 6 U1 1 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0887-8722 J9 J THERMOPHYS HEAT TR JI J. Thermophys. Heat Transf. PD APR-JUN PY 2003 VL 17 IS 2 BP 217 EP 224 DI 10.2514/2.6754 PG 8 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA 667DK UT WOS:000182215500013 ER PT J AU Wright, M Loomis, M Papadopoulos, P AF Wright, M Loomis, M Papadopoulos, P TI Aerothermal analysis of the Project Fire II afterbody flow SO JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER LA English DT Article; Proceedings Paper CT AIAA 35th Thermophysics Conference CY JUN 11-14, 2001 CL ANAHEIM, CALIFORNIA SP Amer Inst Aeronaut & Astronaut ID NAVIER-STOKES EQUATIONS; LINE RELAXATION; COMPUTATION; WAKE AB Computational fluid dynamics is used to simulate the afterbody heating of the Project Fire II ballistic reentry to Earth at 11.35 km/s. Results are obtained over a portion of the trajectory between the initial heat pulse and peak afterbody heating. Although forebody convective heating results are in excellent agreement with previous computations, initial noncatalytic predictions of afterbody heating were a factor of two below the experimental values. However, analogy with currently manufactured thermal protection materials suggests that significant catalysis may be occurring on the afterbody heat shield. Computations including finite rate catalysis are in good agreement with the data over the early portion of the trajectory, but are conservative near the peak afterbody heating point, especially on the rear portion of the conical frustum. Further analysis of the flight data from Fire II shows that peak afterbody heating on the frustum occurs before peak forebody heating, a result that contradicts computations and Right data from other entry vehicles. This result suggests that another mechanism, possibly pyrolysis, may be occurring during the later portion of the trajectory, resulting in less total heat transfer than the current predictions. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 42 TC 20 Z9 22 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0887-8722 J9 J THERMOPHYS HEAT TR JI J. Thermophys. Heat Transf. PD APR-JUN PY 2003 VL 17 IS 2 BP 240 EP 249 DI 10.2514/2.6757 PG 10 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA 667DK UT WOS:000182215500016 ER PT J AU DellaCorte, C AF DellaCorte, C TI Free the carbon... a just mantra 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 APR PY 2003 VL 59 IS 4 BP 3 EP 3 PG 1 WC Engineering, Mechanical SC Engineering GA 674ZE UT WOS:000182667400001 ER PT J AU DellaCorte, C AF DellaCorte, C TI Tribology community suffers loss SO LUBRICATION ENGINEERING LA English DT News Item 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 0 U2 0 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 APR PY 2003 VL 59 IS 4 BP 10 EP 11 PG 2 WC Engineering, Mechanical SC Engineering GA 674ZE UT WOS:000182667400005 ER PT J AU Abdul-Aziz, A Krause, D Tong, M AF Abdul-Aziz, A Krause, D Tong, M TI Characterization of a viscoplastic constitutive model and its application for the finite element analyses of a Stirling space power converter heater head SO MECHANICS OF ADVANCED MATERIALS AND STRUCTURES LA English DT Article AB NASA has identified the Stirling power converter as a prime candidate for the next generation power system for space applications requiring 60,000 hours of operation. To meet this long-term goal, several critical components of the power converter were analyzed using advanced structural assessment methods. Perhaps the most critical component, because of its geometric complexity and operating environment, was the power converter's heater head. Low-cycle fatigue and creep experiments on a nickel-base superalloy, Udimet 720 LI (low inclusions) and viscoplastic analyses for the Stirling starfish heater head were conducted. All testing was performed at temperatures of 625 to 820degreesC in air. This work was initiated to generate a unique and consistent database in support of a life prediction modeling effort aimed at characterizing Freed's viscoplastic model and verifying the key damage mechanisms. In general, this paper describes the life assessment of the heater head, which included the characterization of a viscoplastic material model, the thermal and structural analyses of the heater head, and the interpolation of fatigue and creep test results at several elevated temperatures for life prediction purposes. C1 NASA, Glen Res Ctr, Dept Civil & Environm Engn, Cleveland, OH 44135 USA. NASA, Glen Res Ctr, Life Predict Branch, Cleveland, OH 44135 USA. RP Abdul-Aziz, A (reprint author), NASA, Glen Res Ctr, Dept Civil & Environm Engn, 21000 Brook Pk Rd,MS 6-1, Cleveland, OH 44135 USA. EM smaziz@grc.nasa.gov NR 20 TC 3 Z9 3 U1 0 U2 0 PU TAYLOR & FRANCIS INC PI PHILADELPHIA PA 325 CHESTNUT ST, SUITE 800, PHILADELPHIA, PA 19106 USA SN 1537-6494 J9 MECH ADV MATER STRUC JI Mech. Adv. Mater. Struct. PD APR-JUN PY 2003 VL 10 IS 2 BP 109 EP 125 DI 10.1080/15376490390118157 PG 17 WC Materials Science, Multidisciplinary; Mechanics; Materials Science, Characterization & Testing; Materials Science, Composites SC Materials Science; Mechanics GA 650FR UT WOS:000181252800002 ER PT J AU Holbrook, JB Bost, PR Cave, CB AF Holbrook, JB Bost, PR Cave, CB TI The effects of study-task relevance on perceptual repetition priming SO MEMORY & COGNITION LA English DT Article ID WORD-FRAGMENT COMPLETION; IMPLICIT MEMORY; AFFECTIVE DISCRIMINATION; EXPLICIT MEMORY; OBJECT; RECOGNITION; PICTURES; INVARIANCE; STIMULI; SIZE AB Repetition priming is easily elicited in many traditional paradigms, and the possibility that perceptual priming may be other than an automatic consequence of perception has received little consideration. This issue is explored in two experiments. In Experiment 1, participants named the target from a four-item category search study task more quickly than the nontarget study items at a later naming test. Experiment 2 extended this finding to conditions in which stimuli were individually presented at study. In three different study tasks, stimuli relevant to study-task completion elicited priming on a later test, but stimuli presented outside the context of a task did not. In both experiments, recognition was above chance for nonrelevant stimuli, suggesting that participants explicitly remembered stimuli that did not elicit priming. Results suggest that priming is sensitive to study-task demands and may reflect a more adaptive and flexible mechanism for modification of perceptual processing than previously appreciated. C1 Vanderbilt Univ, Nashville, TN USA. Univ Southampton, Southampton, Hants, England. RP Holbrook, JB (reprint author), NASA, Ames Res Ctr, Mail Stop 262-4, Moffett Field, CA 94035 USA. NR 54 TC 9 Z9 9 U1 2 U2 7 PU PSYCHONOMIC SOC INC PI AUSTIN PA 1710 FORTVIEW RD, AUSTIN, TX 78704 USA SN 0090-502X J9 MEM COGNITION JI Mem. Cogn. PD APR PY 2003 VL 31 IS 3 BP 380 EP 392 DI 10.3758/BF03194396 PG 13 WC Psychology, Experimental SC Psychology GA 683GG UT WOS:000183139600006 PM 12795480 ER PT J AU Fagan, TJ Taylor, GJ Keil, K Hicks, TL Killgore, M Bunch, TE Wittke, JH Mittlefehldt, DW Clayton, RN Mayeda, TK Eugster, O Lorenzetti, S Norman, MD AF Fagan, TJ Taylor, GJ Keil, K Hicks, TL Killgore, M Bunch, TE Wittke, JH Mittlefehldt, DW Clayton, RN Mayeda, TK Eugster, O Lorenzetti, S Norman, MD TI Northwest Africa 773: Lunar origin and iron-enrichment trend SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID SILICATE-LIQUID IMMISCIBILITY; SKAERGAARD LAYERED SERIES; ELECTRON-MICROPROBE; NOBLE-GASES; METEORITE QUEEN-ALEXANDRA-RANGE-94281; OXYGEN ISOTOPES; MELT INCLUSIONS; MARE VOLCANISM; MOON; EVOLUTION AB The meteorite Northwest Africa 773 (NWA 773) is a lunar sample with implications for the evolution of mafic magmas on the moon. A combination of key parameters including whole-rock oxygen isotopic composition, Fe/Mn ratios in mafic silicates, noble gas concentrations, a KREEP-like rare earth element pattern, and the presence of regolith agglutinate fragments indicate a lunar origin for NWA 773. Partial maskelynitization of feldspar and occasional twinning of pyroxene are attributed to shock deformation. Terrestrial weathering has caused fracturing and precipitation of Ca-rich carbonates and sulfates in the fractures, but lunar minerals appear fresh and unoxidized. The meteorite is composed of two distinct lithologies: a two-pyroxene olivine gabbro with cumulate texture, and a polymict, fragmental regolith breccia. The olivine gabbro is dominated by cumulate olivine with pigeonite, augite, and interstitial plagioclase feldspar. The breccia consists of several types of clasts but is dominated by clasts from the gabbro and more FeO-rich derivatives. Variations in clast mineral assemblage and pyroxene Mg/(Mg + Fe) and Ti/(Ti + Cr) record an igneous Fe-enrichment trend that culminated in crystallization of fayalite + silica + hedenbergite-bearing symplectites. The Fe-enrichment trend and cumulate textures observed in NWA 773 are similar to features of terrestrial ponded lava flows and shallow-level mafic intrusives, indicating that NWA 773 may be from a layered mafic intrusion or a thick, differentiated lava flow. NWA 773 and several other mafic lunar meteorites have LREE-enriched patters distinct from Apollo and Luna mare basalts, which tend to be LREE-depleted. This is somewhat surprising in light of remote sensing data that indicates that the Apollo and Luna missions sampled a portion of the moon that was enriched in incompatible heat-producing elements. C1 Univ Hawaii Manoa, Sch Ocean & Earth Sci & Technol, Hawaii Inst Geophys & Planetol, Honolulu, HI 96822 USA. NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. No Arizona Univ, Dept Geol, Flagstaff, AZ 86011 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77258 USA. Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. Univ Bern, Inst Phys, CH-3012 Bern, Switzerland. Australian Natl Univ, Res Sch Earth Sci, Canberra, ACT 0200, Australia. RP Fagan, TJ (reprint author), Tokyo Inst Technol, Meguro Ku, 2-12-1 Ookayama, Tokyo 1528551, Japan. RI Lorenzetti, Silvio/B-1188-2009 OI Lorenzetti, Silvio/0000-0002-8339-8960 NR 92 TC 38 Z9 41 U1 0 U2 9 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 APR PY 2003 VL 38 IS 4 BP 529 EP 554 PG 26 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 713BG UT WOS:000184834900005 ER PT J AU Norman, MD Borg, LE Nyquist, LE Bogard, DD AF Norman, MD Borg, LE Nyquist, LE Bogard, DD TI Chronology, geochemistry, and petrology of a ferroan noritic anorthosite clast from Descartes breccia 67215: Clues to the age, origin, structure, and impact history of the lunar crust SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID AR-39-AR-40 AGE; TRACE-ELEMENTS; MARE BASALTS; MOON; PLAGIOCLASE; CONSTRAINTS; EVOLUTION; ABUNDANCES; SM; CRYSTALLIZATION AB The petrology, major and trace element geochemistry, and Nd-Ar-Sr isotopic compositions of a ferroan noritic anorthosite clast from lunar breccia 67215 have been studied in order to improve our understanding of the composition, age, structure, and impact history of the lunar crust. The clast (designated 67215c) has an unusually well preserved igneous texture. Mineral compositions are consistent with classification of 67215c as a member of the ferroan anorthositic suite of lunar highlands rocks, but the texture and mineralogy show that it cooled more rapidly and at shallower depths than did more typical ferroan anorthosites (FANs). Incompatible trace element concentrations are enriched in 67215c relative to typical FANs, but diagnostic signatures such as Ti/Sm, Sc/Sm, plagiophile element ratios, and the lack of Zr/Hf and Nb/Ta fractionation show that this cannot be due to the addition of KREEP. Alternatively, 67215c may contain a greater fraction of trapped liquid than is commonly present in lunar FANs. Sm-147-Nd-143 isotopic compositions of mineral separates from 67215c define an isochron age of 4.40 +/- 0.11 Gyr with a near-chondritic initial epsilon(Nd)(143) of +0.85 +/- 0.53. The Ar-40-Ar-39 composition of plagioclase from this clast records a post-crystallization thermal event at 3.93 +/- 0.08 Gyr, with the greatest contribution to the uncertainty in this age deriving from a poorly constrained correction for lunar atmosphere Ar-40. Rb-Sr isotopic compositions are disturbed, probably by the same event recorded by the Ar isotopic compositions. Trace element compositions of FANs are consistent with crystallization from a moderately evolved magma ocean and do not support a highly depleted source composition such as that implied by the positive initial epsilon(Nd)(143) of the ferroan noritic anorthosite 62236. Alternatively, the Nd isotopic systematics of lunar FANs may have been subject to variable degrees of modification by impact metamorphism, with the plagioclase fraction being more strongly affected than the mafic phases. (SM)-S-147-Nd-143 isotopic compositions of mafic fractions from the 4 ferroan noritic anorthosites for which isotopic data exist (60025, 62236, 67016c, 67215c) define an age of 4.46 +/- 0.04 Gyr, which may provide a robust estimate for the crystallization age of lunar ferroan anorthosites. C1 Australian Natl Univ, Res Sch Earth Sci, Canberra, ACT 0200, Australia. Univ New Mexico, Inst Meteorit, Albuquerque, NM 87131 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Norman, MD (reprint author), Australian Natl Univ, Res Sch Earth Sci, Canberra, ACT 0200, Australia. NR 61 TC 85 Z9 87 U1 1 U2 11 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 APR PY 2003 VL 38 IS 4 BP 645 EP 661 PG 17 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 713BG UT WOS:000184834900011 ER PT J AU Kagawa, HK Yaoi, T Brocchieri, L McMillan, RA Alton, T Trent, JD AF Kagawa, HK Yaoi, T Brocchieri, L McMillan, RA Alton, T Trent, JD TI The composition, structure and stability of a group II chaperonin are temperature regulated in a hyperthermophilic archaeon SO MOLECULAR MICROBIOLOGY LA English DT Article ID THERMOCOCCUS STRAIN KS-1; HEAT-SHOCK PROTEINS; SULFOLOBUS-SOLFATARICUS; MOLECULAR CHAPERONES; ESCHERICHIA-COLI; 2 KINDS; THERMOSOME; EVOLUTION; TRANSCRIPTION; SHIBATAE AB The hyperthermoacidophilic archaeon Sulfolobus shibatae contains group II chaperonins, known as rosettasomes, which are two nine-membered rings composed of three different 60 kDa subunits (TF55 alpha, beta and gamma). We sequenced the gene for the gamma subunit and studied the temperature-dependent changes in alpha, beta and gamma expression, their association into rosettasomes and their phylogenetic relationships. Alpha and beta gene expression was increased by heat shock (30 min, 86degreesC) and decreased by cold shock (30 min, 60degreesC). Gamma expression was undetectable at heat shock temperatures and low at normal temperatures (75-79degreesC), but induced by cold shock. Polyacrylamide gel electrophoresis indicated that in vitro alpha and beta subunits form homo-oligomeric rosettasomes, and mixtures of alpha, beta and gamma form hetero-oligomeric rosettasomes. Transmission electron microscopy revealed that beta homo-oligomeric rosettasomes and all hetero-oligomeric rosettasomes associate into filaments. In vivo rosettasomes were hetero-oligomeric with an average subunit ratio of 1alpha:1beta:0.1gamma in cultures grown at 75degreesC, a ratio of 1alpha:3beta:1gamma in cultures grown at 60degreesC and a ratio of 2alpha:3beta:0gamma after 86degreesC heat shock. Using differential scanning calorimetry, we determined denaturation temperatures (T-m ) for alpha, beta and gamma subunits of 95.7degreesC, 96.7degreesC and 80.5degreesC, respectively, and observed that rosettasomes containing gamma were relatively less stable than those with alpha and/or beta only. We propose that, in vivo , the rosettasome structure is determined by the relative abundance of subunits and not by a fixed geometry. Furthermore, phylogenetic analyses indicate that archaeal chaperonin subunits underwent multiple duplication events within species (paralogy). The independent evolution of these paralogues raises the possibility that chaperonins have functionally diversified between species. C1 NASA, Ames Res Ctr, Astrobiol Technol Branch, Moffett Field, CA 94035 USA. Western Illinois Univ, Dept Biol Sci, Macomb, IL 61055 USA. SETI Inst, Mountain View, CA 94043 USA. Univ Calif Berkeley, Dept Plant & Microbial Sci, Berkeley, CA 94720 USA. Stanford Univ, Dept Math, Stanford, CA 94305 USA. RP Trent, JD (reprint author), NASA, Ames Res Ctr, Astrobiol Technol Branch, Moffett Field, CA 94035 USA. EM JONATHAN.D.TRENT@nasa.gov NR 56 TC 46 Z9 46 U1 0 U2 2 PU BLACKWELL PUBLISHING LTD PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DG, OXON, ENGLAND SN 0950-382X J9 MOL MICROBIOL JI Mol. Microbiol. PD APR PY 2003 VL 48 IS 1 BP 143 EP 156 DI 10.1046/j.1365-2958.2003.03418.x PG 14 WC Biochemistry & Molecular Biology; Microbiology SC Biochemistry & Molecular Biology; Microbiology GA 659XB UT WOS:000181802600012 PM 12657051 ER PT J AU Rubin, RH Martin, PG Dufour, RJ Ferland, GJ Blagrave, KPM Liu, XW Nguyen, JF Baldwin, JA Bohlin, R Hartig, G Bohlin, R Collins, N Gonnella, A AF Rubin, RH Martin, PG Dufour, RJ Ferland, GJ Blagrave, KPM Liu, XW Nguyen, JF Baldwin, JA Bohlin, R Hartig, G Bohlin, R Collins, N Gonnella, A TI Temperature variations from Hubble Space Telescope spectroscopy of the Orion Nebula SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE ISM : abundances; ISM : atoms; HII regions; ISM : individual : NGC 1976; ISM : individual : proplyd P159-350 ID OPTICAL RECOMBINATION LINES; HERBIG-HARO OBJECTS; PLANETARY-NEBULAE; CHEMICAL-COMPOSITION; COLLISION STRENGTHS; PHYSICAL CONDITIONS; ATOMIC DATA; O-II; ABUNDANCES; NGC-7009 AB We present Hubble Space Telescope (HST)/STIS long-slit spectroscopy of NGC 1976. Our goal is to measure the intrinsic line ratio [O III] 4364/5008 and thereby evaluate the electron temperature (T-e) and the fractional mean-square T-e variation (t(A)(2)) across the nebula . We also measure the intrinsic line ratio [N II] 5756/6585 in order to estimate T-e and t(A)(2) in the N+ region. The interpretation of the [N II] data is not as clear cut as the [O III] data because of a higher sensitivity to knowledge of the electron density as well as a possible contribution to the [N II] 5756 emission by recombination (and cascading). We present results from binning the data along the various slits into tiles that are 0.5 arcsec square (matching the slit width). The average [O III] temperature for our four HST/STIS slits varies from 7678 K to 8358 K; t(A)(2) varies from 0.00682 to at most 0.0176. For our preferred solution, the average [N II] temperature for each of the four slits varies from 9133 to 10 232 K; t(A)(2) varies from 0.00584 to 0.0175. The measurements of T-e reported here are an average along each line of sight. Therefore, despite finding remarkably low t(A)(2), we cannot rule out significantly larger temperature fluctuations along the line of sight. The result that the average [N II] T-e exceeds the average [O III] T-e confirms what has been previously found for Orion and what is expected on theoretical grounds. Observations of the proplyd P159-350 indicate: large local extinction associated; ionization stratification consistent with external ionization by theta(1) Ori C; and indirectly, evidence of high electron density. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Orion Enterprises, Moffett Field, CA 94035 USA. Univ Toronto, Canadian Inst Theoret Astrophys, Toronto, ON M5S 3H8, Canada. Rice Univ, Dept Phys & Astron, Houston, TX 77005 USA. Univ Kentucky, Dept Phys & Astron, Lexington, KY 40506 USA. Peking Univ, Dept Astron, Beijing 100871, Peoples R China. Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA. RP Rubin, RH (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM rubin@cygnus.arc.nasa.gov OI Ferland, Gary/0000-0003-4503-6333 NR 40 TC 35 Z9 35 U1 0 U2 1 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 APR 1 PY 2003 VL 340 IS 2 BP 362 EP 374 DI 10.1046/j.1365-8711.2003.06185.x PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 658VG UT WOS:000181740700002 ER PT J AU Howard, A Padgett, C AF Howard, A Padgett, C TI An adaptive learning methodology for intelligent object detection in novel imagery data SO NEUROCOMPUTING LA English DT Article DE target detection; neural networks; pattern recognition ID AUTOMATIC TARGET RECOGNITION AB The process of robustly identifying targets embedded in a cluttered image scene is a difficult task to accomplish. Such an application must deal with rotation, scaling, and lighting variants of the target as well as handle the varying degrees of unpredictability in the image scene itself. To assume that an object will always reside in the same background environment during the detection process as in the learning phase is an overgeneralization that is unrealistic. To address this problem, we present a technique that learns to identify targets embedded in a cluttered image scene and robustly re-trains when presented with novel imagery data. The algorithm utilizes a two-stage process in which a baseline clustering/neural network methodology is used to first recognize targets embedded in an original image data set and an adaptive clustering/neural network technique is subsequently applied as images are re-examined for novelty. We show that the algorithm developed achieves a 99% recognition rate with a 0.9% false alarm rate for previously unseen background images. (C) 2002 Elsevier Science B.V. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0925-2312 EI 1872-8286 J9 NEUROCOMPUTING JI Neurocomputing PD APR PY 2003 VL 51 BP 1 EP 11 AR PII S0925-2312(02)00598-2 DI 10.1016/S0925-2312(02)00598-2 PG 11 WC Computer Science, Artificial Intelligence SC Computer Science GA 661WJ UT WOS:000181912600001 ER PT J AU Beacom, JF AF Beacom, JF TI Supernovae and neutrinos SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 20th International Conference on Neutrino Physics and Astrophysics CY MAY 25-30, 2002 CL MUNICH, GERMANY SP Techn Univ Munchen, Max Planck Inst Phys, Werner Heisenberg Inst ID PROTON ELASTIC-SCATTERING; ART. NO. 033007; CORE-COLLAPSE; POSTBOUNCE EVOLUTION; NU(TAU) NEUTRINOS; CHARGED-PARTICLES; NEUTRAL-CURRENT; MASS SIGNATURE; SPECTRUM; OSCILLATIONS AB A long-standing problem in supernova physics is how to measure the total energy and temperature of nu(mu), nu(tau), nu(mu), and nu(tau). While of the highest importance, this is very difficult because these flavors only have neutral-current detector interactions. We propose that neutrino-proton elastic scattering, nu + p --> nu + p, can be used for the detection of supernova, neutrinos in scintillator detectors. It should be emphasized immediately that the dominant signal is on free protons. Though the proton recoil kinetic energy spectrum is soft, with T-p similar or equal to 2E(nu)(2)/M-p, and the scintillation light output from slow, heavily ionizing protons is quenched, the yield above a realistic threshold is nearly as large as that from nu(e) + p --> e(+) + n. In addition, the measured proton spectrum is related to the incident neutrino spectrum. The ability to detect this signal would give detectors like KamLAND and Borexino a crucial and unique role in the quest to detect supernova, neutrinos. These results are now published: J. F. Beacom, W. M. Farr and P. Vogel, Phys. Rev. D 66, 033001 (2002) [arXiv:hep-ph/0205220]; the details axe given there [1]. C1 NASA, Fermilab Astrophys Ctr, Fermilab, Batavia, IL 60510 USA. RP NASA, Fermilab Astrophys Ctr, Fermilab, Batavia, IL 60510 USA. EM beacom@fnal.gov OI Beacom, John/0000-0002-0005-2631 NR 55 TC 5 Z9 5 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 EI 1873-3832 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD APR PY 2003 VL 118 BP 307 EP 314 DI 10.1016/S0920-5632(03)01323-9 PG 8 WC Physics, Particles & Fields SC Physics GA 677GW UT WOS:000182799400032 ER PT J AU Papalexandris, MV Waluschka, E AF Papalexandris, MV Waluschka, E TI Numerical phase front propagation for a large-baseline space interferometer SO OPTICAL ENGINEERING LA English DT Article DE space; interferometry; gravitational waves; diffraction algorithms; Monte Carlo simulations ID FIELD AB We report on numerical studies of phase front propagation for a large-baseline space interferometer. The main objective is to determine the sensitivity of the average phase of the metrology beam with respect to fluctuations in the pointing of the beam. For this purpose, the metrology beam is propagated numerically along the interferometric arm of the instrument. The effects of the obscurations from the secondary mirror and its supporting struts are studied in detail. Further, the effects of wavefront distortions that occur due to imperfections of the optical elements are estimated through a series of Monte Carlo simulations. The results of this study can be used to determine design requirements for the instrument. (C) 2003 Society of Photo-Optical Instrumentation Engineers. C1 Univ Catholique Louvain, Dept Mecan, B-1348 Louvain, Belgium. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Papalexandris, MV (reprint author), Univ Catholique Louvain, Dept Mecan, B-1348 Louvain, Belgium. NR 9 TC 0 Z9 0 U1 1 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 APR PY 2003 VL 42 IS 4 BP 1029 EP 1037 DI 10.1117/1.1558087 PG 9 WC Optics SC Optics GA 666UE UT WOS:000182194200023 ER PT J AU Zhang, NL Chao, DF AF Zhang, NL Chao, DF TI Caustics and caustic-diffraction in laser shadowgraphy of a sessile drop and identification of profile near contact line SO OPTICS AND LASER TECHNOLOGY LA English DT Article DE shadowgraphic image; sessile drop; caustic diffraction AB This paper presents an optical method based on the caustics and caustic-diffraction in laser shadowgraphy of a sessile drop to identify and estimate the drop profile near the contact line. A parallel laser beam passes through a liquid sessile drop placed on a transparent substrate to produce a shadowgraphic image of the drop on the screen far from the substrate. Along the inflection line of the drop the Gaussian curvature of the wavefront deformed by the drop vanishes, and therefore the inflection line gives caustics in the far field of the wave, which can be seen on the screen. The neighboring light rays at both sides of the inflection line interfere with each other to form interference fringes at the inner side of the caustics. According to the pattern of the caustics, the drop-profile shape can be identified and estimated. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Zhang, NL (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 10 TC 3 Z9 3 U1 0 U2 1 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0030-3992 J9 OPT LASER TECHNOL JI Opt. Laser Technol. PD APR PY 2003 VL 35 IS 3 BP 155 EP 161 DI 10.1016/S0030-3992(02)00161-5 PG 7 WC Optics; Physics, Applied SC Optics; Physics GA 650FU UT WOS:000181253000001 ER PT J AU Yu, JR Braud, A Petros, M AF Yu, JR Braud, A Petros, M TI 600-mJ, double-pulse 2-mu m laser SO OPTICS LETTERS LA English DT Article ID TM-YLF LASER; HO AB An efficient double-pulse Ho:Tm:YLF 2-mum laser with total Q-switched output energy of 600 mJ has been demonstrated. A double-pulse pair is obtained per pump pulse. By operation of the laser in a double-pulse format, the residual energy stored among the Tm ions is transferred to the Ho atoms that were de-excited by the extraction of the first Q-switched pulse. Thus, the overall laser efficiency is increased by 61%. (C) 2003 Optical Society of America. C1 NASA, Langley Res Ctr, Laser & Electroopt Branch, Hampton, VA 23681 USA. Inst Sci Mat & Rayonnement, Ctr Interdisciplinaire Rech Ions Lasers, F-14000 Caen, France. Sci & Technol Corp, Hampton, VA 23666 USA. RP Yu, JR (reprint author), NASA, Langley Res Ctr, Laser & Electroopt Branch, MS 468, Hampton, VA 23681 USA. EM jirong.yu@larc.nasa.gov NR 8 TC 37 Z9 42 U1 0 U2 5 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD APR 1 PY 2003 VL 28 IS 7 BP 540 EP 542 DI 10.1364/OL.28.000540 PG 3 WC Optics SC Optics GA 657RK UT WOS:000181680000014 PM 12696609 ER PT J AU Pohorille, A Wilson, MA Chipot, C AF Pohorille, A Wilson, MA Chipot, C TI Membrane peptides and their role in protobiological evolution SO ORIGINS OF LIFE AND EVOLUTION OF BIOSPHERES LA English DT Review DE membrane peptides; peptide folding at interfaces; peptide-membrane interactions; peptide-petide association; Influenza M2 proton channel; protocellular functions; origin of membrane proteins ID INFLUENZA-A VIRUS; MOLECULAR-DYNAMICS SIMULATION; M-2 ION-CHANNEL; TRANSFORM INFRARED-SPECTROSCOPY; TRANSMEMBRANE ALPHA-HELICES; FREE-ENERGY CALCULATIONS; LIPID BILAYER-MEMBRANES; WATER-HEXANE INTERFACE; SYNTHETIC PEPTIDES; PHOSPHOLIPID-BILAYERS AB How simple membrane peptides performed such essential protocellular functions as transport of ions and organic matter across membranes separating the interior of the cell from the environment, capture and utilization of energy, and transduction of environmental signals, is a key question in protobiological evolution. On the basis of detailed, molecular-level computer simulations we explain how these peptides fold at water-membrane interfaces, insert into membranes, self-assemble into higher-order structures and acquire functions. We have investigated the interfacial behavior and folding of several peptides built of leucine and glutamine residues and have demonstrated that many of them tend to adopt ordered structures. Further, we have studied the insertion of an alpha-helical peptide containing leucine (L) and serine (S) of the form (LSLLLSL)(3) into a model membrane. The transmembrane state is metastable, and approximately 15 kcal mol(-1) is required to insert the peptide into the membrane. Investigations of dimers formed by (LSLLLSL)(3) and glycophorin A demonstrate how the favorable free energy of helix association can offset the unfavorable free energy of insertion, leading to self-assembly of peptide helices in the membrane. An example of a self-assembled structure is the tetrameric transmembrane pore of the influenza virus M2 protein, which is an efficient and selective voltage-gated proton channel. Our simulations explain the gating mechanism and provide guidelines how to re-engineer the channel to act as a simple proton pump. In general, emergence of integral membrane proteins appears to be quite feasible and may be easier to envision than the emergence of water-soluble proteins. C1 NASA, Exobiol Branch, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Calif San Francisco, Dept Pharmaceut Chem, San Francisco, CA 94143 USA. Univ Nancy 1, Chim Theor Lab, CNRS, Unite Mixte Rech 7565, F-54506 Vandoeuvre Les Nancy, France. RP Pohorille, A (reprint author), NASA, Exobiol Branch, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 106 TC 12 Z9 13 U1 2 U2 9 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0169-6149 J9 ORIGINS LIFE EVOL B JI Orig. Life Evol. Biosph. PD APR PY 2003 VL 33 IS 2 BP 173 EP 197 DI 10.1023/A:1024627726231 PG 25 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 699RT UT WOS:000184070300004 PM 12967266 ER PT J AU Smirnov, A Schoonen, MAA AF Smirnov, A Schoonen, MAA TI Evaluating experimental artifacts in hydrothermal prebiotic synthesis experiments SO ORIGINS OF LIFE AND EVOLUTION OF THE BIOSPHERE LA English DT Article; Proceedings Paper CT Astrobiology Science Conference CY APR 07-11, 2002 CL MOFFETT, CALIFORNIA DE acetate; contamination; formate; hydrothermal; prebiotic synthesis ID THERMAL-DECOMPOSITION; FORMIC-ACID; OXIDATION; SPECTROSCOPY; KINETICS; SURFACES; CARBON AB Control experiments with ultra pure deionized water were conducted to evaluate the organic contamination in hydrothermal prebiotic experiments. Different combinations of reaction vessel material, sampling tubing and stirring were tested and the amounts of organic contaminants determined. All tested types of polymer tubing were proven to introduce organic contaminants ( formate, acetate and propionate ions) into the reacting solution. Stainless steel has a catalytic effect on the decomposition of formate, consistent with earlier work at high temperatures and pressures. C1 SUNY Stony Brook, NASA, Astrobiol Inst, Stony Brook, NY 11794 USA. SUNY Stony Brook, Dept Geosci, Stony Brook, NY 11794 USA. RP Smirnov, A (reprint author), SUNY Stony Brook, NASA, Astrobiol Inst, Stony Brook, NY 11794 USA. RI Schoonen, martin/E-7703-2011; Smirnov, Alexander/D-4672-2009 OI Schoonen, martin/0000-0002-7133-1160; Smirnov, Alexander/0000-0001-8665-5187 NR 13 TC 7 Z9 7 U1 1 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0169-6149 J9 ORIGINS LIFE EVOL B JI Orig. Life Evol. Biosph. PD APR PY 2003 VL 33 IS 2 BP 117 EP 127 DI 10.1023/A:1024621500930 PG 11 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 699RT UT WOS:000184070300001 PM 12967263 ER PT J AU Tumer, K Oza, NC AF Tumer, K Oza, NC TI Input decimated ensembles SO PATTERN ANALYSIS AND APPLICATIONS LA English DT Article DE classification; combining classifier; correlation reduction; dimensionality reduction; ensembles; feature selection ID PRINCIPAL COMPONENTS; NEURAL NETWORKS; SELECTION; FEATURES AB Using an ensemble of classifiers instead of a single classifier has been shown to improve generalization performance in many pattern recognition problems. However, the extent of such improvement depends greatly on the amount of correlation among the errors of the base classifiers. Therefore, reducing those correlations while keeping the classifiers' performance levels high is an important area of research. In this article, we explore Input Decimation (ID), a method which selects feature subsets for their ability to discriminate among the classes and uses these subsets to decouple the base classifiers. We provide a summary of the theoretical benefits of correlation reduction, along with results of our method on two underwater sonar data sets, three benchmarks from the Probenl/UCI repositories, and two synthetic data sets. The results indicate that input decimated ensembles outperform ensembles whose base classifiers use all the input features; randomly selected subsets of features; and features created using principal components analysis, on a wide range of domains. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Tumer, K (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 52 TC 39 Z9 40 U1 0 U2 2 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 1433-7541 J9 PATTERN ANAL APPL JI Pattern Anal. Appl. PD APR PY 2003 VL 6 IS 1 BP 65 EP 77 DI 10.1007/s10044-002-0181-7 PG 13 WC Computer Science, Artificial Intelligence SC Computer Science GA 687NF UT WOS:000183382700008 ER PT J AU Ambrosia, VG Wegener, SS Sullivan, DV Buechel, SW Dunagan, SE Brass, JA Stoneburner, J Schoenung, SM AF Ambrosia, VG Wegener, SS Sullivan, DV Buechel, SW Dunagan, SE Brass, JA Stoneburner, J Schoenung, SM TI Demonstrating UAV-acquired real-time thermal data over fires SO PHOTOGRAMMETRIC ENGINEERING AND REMOTE SENSING LA English DT Article AB Project FiRE (First Response Experiment), a disaster management technology demonstration, was performed in 2001. The experiment demonstrated the use of a thermal multispectral scanning imager, integrated on an unmanned aerial vehicle (UAV), a satellite uplink/downlink image data telemetry system, and near-real-time geo-rectification of the resultant imagery for data distribution via the Internet to disaster managers. The FiRE demonstration provided geo-corrected image data over a controlled burn to a fire management community in near-real-time by means of the melding of new technologies. The use of the UAV demonstrated remotely piloted flight (thereby reducing the potential for loss of human life during hazardous missions), and the ability to "linger and stare" over the fire for extended periods of time (beyond the capabilities of human-pilot endurance). Improvements in a high-temperature calibrated thermal imaging scanner allowed "remote" operations from a UAV and provided real-time accurate fire information collection over a controlled burn. Improved bit-rate capacity telemetry capabilities increased the amount, structure, and information content of the image data relayed to the ground. The integration of precision navigation instrumentation allowed improved accuracies in geo-rectification of the resultant imagery, easing data ingestion and overlay in a GIS framework. We present a discussion of the feasibility of utilizing new platforms, improved sensor configurations, improved telemetry, and new geo-correction software to facilitate wildfire management and mitigation strategies,. C1 Calif State Univ Monterey Bay, NASA, Ames Res Ctr, Earth Syst Sci & Policy Inst, Moffett Field, CA 94035 USA. Terra Mar Resources Informat Serv, Hood River, OR 97031 USA. Gen Atom Aeronaut Syst Inc, San Diego, CA 92127 USA. Longitude 122 W Inc, Menlo Pk, CA 94025 USA. RP Ambrosia, VG (reprint author), Calif State Univ Monterey Bay, NASA, Ames Res Ctr, Earth Syst Sci & Policy Inst, Moffett Field, CA 94035 USA. EM vambrosia@mail.arc.nasa.gov; swegener@mail.arc.nasa.gov; dvsullivan@mail.arc.nasa.gov; sbuechel@ix.netcom.com; sdunagan@mail.arc.nasa.gov; jbrass@mail.arc.nasa.gov; jay.stoneburner@gat.com; schoenung@aol.com NR 27 TC 35 Z9 37 U1 3 U2 22 PU AMER SOC PHOTOGRAMMETRY PI BETHESDA PA 5410 GROSVENOR LANE SUITE 210, BETHESDA, MD 20814-2160 USA SN 0099-1112 J9 PHOTOGRAMM ENG REM S JI Photogramm. Eng. Remote Sens. PD APR PY 2003 VL 69 IS 4 BP 391 EP 402 PG 12 WC Geography, Physical; Geosciences, Multidisciplinary; Remote Sensing; Imaging Science & Photographic Technology SC Physical Geography; Geology; Remote Sensing; Imaging Science & Photographic Technology GA 817QW UT WOS:000221193000008 ER PT J AU Seo, JT Yang, Q Creekmore, S Temple, D Qu, L Yu, W Wang, A Peng, X Mott, A Namkung, M Junge, SS Kim, JH AF Seo, JT Yang, Q Creekmore, S Temple, D Qu, L Yu, W Wang, A Peng, X Mott, A Namkung, M Junge, SS Kim, JH TI Evaluation of nonlinear optical properties of cadmium chalcogenide nanomaterials SO PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES LA English DT Article; Proceedings Paper CT International Conference on Superlattices Nano-Structures and Nano-Devices (ICSNN-02) CY JUL 22-26, 2002 CL TOULOUSE, FRANCE DE nonlinear refraction; nonlinear figure of merit; optical power limiter; semiconductor nanoscale materials AB High quality semiconductor nanomaterials were synthesized through colloidal methods, and evaluated nonlinear optical properties for optical power limiting applications. The nonlinear refraction (gamma) and the nonlinear figure of merit (FOM = gamma/betagamma) of CdTe nanomaterials in toluene (similar to 8 x 10(-5) mol/l) were estimated to be similar to -1 x 10(-13) m(2)/W and similar to 200, respectively. The optical power limiting through CdTe nanoscale materials was mainly by the nonlinear refraction because of the high nonlinear FOM. (C) 2002 Elsevier Science B.V. All rights reserved. C1 Hampton Univ, Dept Phys, Res Ctr Opt Phys, Hampton, VA 23668 USA. Univ Arkansas, Dept Chem & Biochem, Fayetteville, AR 72701 USA. USA, Res Lab, Adelphi, MD 20783 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Korea Res Inst Standards & Sci, Taejon 305600, South Korea. RP Seo, JT (reprint author), Hampton Univ, Dept Phys, Res Ctr Opt Phys, Hampton, VA 23668 USA. RI Namkung, Min/E-1533-2012 NR 2 TC 6 Z9 6 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1386-9477 J9 PHYSICA E JI Physica E PD APR PY 2003 VL 17 IS 1-4 BP 101 EP 103 DI 10.1016/S1386-9477(02)00714-2 PG 3 WC Nanoscience & Nanotechnology; Physics, Condensed Matter SC Science & Technology - Other Topics; Physics GA 675ND UT WOS:000182700700033 ER PT J AU Matsko, AB Yu, N Maleki, L AF Matsko, AB Yu, N Maleki, L TI Gravity field measurements using cold atoms with direct optical readout SO PHYSICAL REVIEW A LA English DT Article ID INTERFEROMETRY; COHERENCE; FORCES; LIGHT AB We show theoretically that measuring an optimum observable of an electromagnetic wave propagating in an atomic medium moving freely in a gravitational field results in a sensitive detection of the acceleration of gravity and its gradient. The best achievable sensitivity of such a measurement is comparable with that of light-pulse atom interferometers based on measuring the atomic internal state. This optical technique is useful for nondestructive detection of ultracold atoms in atomic interferometers. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Matsko, Andrey/A-1272-2007 NR 23 TC 4 Z9 4 U1 0 U2 2 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9926 EI 2469-9934 J9 PHYS REV A JI Phys. Rev. A PD APR PY 2003 VL 67 IS 4 AR 043819 DI 10.1103/PhysRevA.67.043819 PG 12 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 673WY UT WOS:000182604300128 ER PT J AU Foygel, M Morris, RD Petukhov, AG AF Foygel, M Morris, RD Petukhov, AG TI Variable-range hopping of spin polarons: Magnetoresistance in a modified Mott regime SO PHYSICAL REVIEW B LA English DT Article ID BOUND MAGNETIC POLARON; SEMICONDUCTORS; PERCOLATION AB We analize electrical conductivity controlled by hopping of bound spin polarons in disordered solids with wide distributions of electron energies and polaron shifts (barriers). By means of percolation theory and Monte Carlo simulations we have shown that in such materials at low temperatures, when hopping occurs in the vicinity of the Fermi level, a hard polaron gap does not manifest itself in the transport properties. This happens because as temperature decreases the hopping polaron trades the decreasing electron and polaron barriers for increasing hopping distance. As a result, in the absence of the Coulomb correlation effects, in this variable-range variable-barrier hopping regime, the electrical resistivity, rho, as a function of temperature, T, obeys a nonactivation law: ln(rho/rho(0))=(T/T)(p) with p=2/(d+2), where d is the dimensionality of the system. It differs from the standard Mott law for which p=1/(d+1). Also, we studied the effects of upper and lower boundaries in the polaron shift distribution on hopping conduction, which may result in a partial reentrance of the hard polaron gap. We discuss possible applications to the problem of giant negative magnetoresistance in dilute magnetic semiconductors and nanocomposites where for paramanetic materials p=3/(d+2). C1 S Dakota Sch Mines & Technol, Dept Phys, Rapid City, SD 57701 USA. NASA, USRA RIACS, Ames Res Ctr, Moffett Field, CA 94035 USA. USN, Ctr Computat Mat Sci, Res Lab, Washington, DC 20375 USA. RP Foygel, M (reprint author), S Dakota Sch Mines & Technol, Dept Phys, Rapid City, SD 57701 USA. NR 22 TC 17 Z9 18 U1 2 U2 9 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 J9 PHYS REV B JI Phys. Rev. B PD APR 1 PY 2003 VL 67 IS 13 AR 134205 DI 10.1103/PhysRevB.67.134205 PG 9 WC Physics, Condensed Matter SC Physics GA 673WW UT WOS:000182604100047 ER PT J AU Boezio, M Bonvicini, V Schiavon, P Vacchi, A Zampa, N Bergstrom, D Carlson, P Francke, T Hansen, P Mocchiutti, E Suffert, M Hof, M Kremer, J Menn, W Simon, M Ambriola, M Bellotti, R Cafagna, F Ciacio, F Circella, M De Marzo, CN Papini, P Piccardi, S Spillantini, P Vannuccini, E Bartalucci, S Ricci, M Casolino, M De Pascale, MP Morselli, A Picozza, P Sparvoli, R Mitchell, JW Ormes, JF Stephens, SA Streitmatter, RE Bravar, U Stochaj, SJ AF Boezio, M Bonvicini, V Schiavon, P Vacchi, A Zampa, N Bergstrom, D Carlson, P Francke, T Hansen, P Mocchiutti, E Suffert, M Hof, M Kremer, J Menn, W Simon, M Ambriola, M Bellotti, R Cafagna, F Ciacio, F Circella, M De Marzo, CN Papini, P Piccardi, S Spillantini, P Vannuccini, E Bartalucci, S Ricci, M Casolino, M De Pascale, MP Morselli, A Picozza, P Sparvoli, R Mitchell, JW Ormes, JF Stephens, SA Streitmatter, RE Bravar, U Stochaj, SJ TI Energy spectra of atmospheric muons measured with the CAPRICE98 balloon experiment SO PHYSICAL REVIEW D LA English DT Article ID GAS-RICH DETECTOR; COSMIC-RAY; MAGNETIC SPECTROMETER; FLUX; PERFORMANCE; COLLABORATION; NEUTRINOS; SOUDAN-2; ALTITUDE; HELIUM AB The measurement of the atmospheric muon spectrum is currently of great interest because of the study of atmospheric neutrinos and the claim of neutrino oscillations made in 1998 by the Super-Kamiokande Collaboration. A measurement of the muon flux is an indirect measure of the neutrino flux. Therefore, it can be used to improve the calculation of the atmospheric neutrino flux, which in turn can be compared with the observed neutrino rates in underground detectors. This article reports a new measurement of the mu(+) and mu(-) spectra at several atmospheric depths in the momentum ranges 0.3-20 GeV/c and 0.3-40 GeV/c, respectively. The data were collected by the balloon-borne experiment CAPRICE98 during the ascent of the payload on 28 May 1998 from Fort Sumner, N. M. The experiment used the NMSU-WIZARD/CAPRICE 98 balloon-borne magnet spectrometer equipped with a gas ring imaging Cherenkov detector and a silicon-tungsten calorimeter. C1 Univ Trieste, I-34147 Trieste, Italy. Sez INFN Trieste, I-34147 Trieste, Italy. AlbaNova Univ Ctr SCFAB, Royal Inst Technol KTH, S-10691 Stockholm, Sweden. Ctr Rech Nucl, F-67037 Strasbourg, France. Univ Siegen, D-57068 Siegen, Germany. Univ Florence, I-50125 Florence, Italy. Sez INFN Firenze, I-50125 Florence, Italy. Univ Bari, I-70126 Bari, Italy. Sez INFN Bari, I-70126 Bari, Italy. Ist Nazl Fis Nucl, Lab Nazl Frascati, I-00044 Frascati, Italy. Univ Roma Tor Vergata, I-00133 Rome, Italy. Sez INFN Roma II, I-00133 Rome, Italy. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. New Mexico State Univ, RL Golden Particle Astrophys Lab, Las Cruces, NM 88003 USA. RP Boezio, M (reprint author), Univ Trieste, Via A Valerio 2, I-34147 Trieste, Italy. RI Morselli, Aldo/G-6769-2011; Cafagna, Francesco/A-9299-2010; Mocchiutti, Emiliano/I-8049-2013; Vacchi, Andrea/C-1291-2010; OI Morselli, Aldo/0000-0002-7704-9553; Cafagna, Francesco/0000-0002-7450-4784; Mocchiutti, Emiliano/0000-0001-7856-551X; Vacchi, Andrea/0000-0003-3855-5856; Boezio, Mirko/0000-0002-8015-2981 NR 39 TC 31 Z9 31 U1 0 U2 0 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 APR PY 2003 VL 67 IS 7 AR 072003 DI 10.1103/PhysRevD.67.072003 PG 15 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 675VZ UT WOS:000182718300011 ER PT J AU Lorenz, RD Biolluz, G Encrenaz, P Janssen, MA West, RD Muhleman, DO AF Lorenz, RD Biolluz, G Encrenaz, P Janssen, MA West, RD Muhleman, DO TI Cassini RADAR: prospects for Titan surface investigations using the microwave radiometer SO PLANETARY AND SPACE SCIENCE LA English DT Article DE microwave; radiometry; remote sensing; Titan ID VENUS SURFACE; DIELECTRIC-PROPERTIES; PHYSICAL-PROPERTIES; ICY SATELLITES; TROPOSPHERE; ATMOSPHERE; MAGELLAN; METHANE; IMAGES; SYSTEM AB The Radar instrument on the Cassini spacecraft can be used in a passive radiometric mode to map the microwave emission from Titan: these will be the first resolved microwave emission measurements of an icy satellite. Observation plans and the theory for their interpretation is presented: these data should be able to provide crude composition maps of Titan's surface, confirm equator-to-pole temperature gradients without the influence of the atmospheric effects which affect infrared observations and place constraints on surface and subsurface temperature variations. Additionally, passive radiometry will also provide some bistatic reflection measurements, using the sun as a source, which may be used to constrain roughness of ethane seas. (C) 2003 Elsevier Science Ltd. All rights reserved. C1 Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. DEMIRM, F-75014 Paris, France. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Dept Geol & Planetary Sci, Pasadena, CA 91125 USA. RP Lorenz, RD (reprint author), Univ Arizona, Lunar & Planetary Lab, 1629 E Univ Blvd, Tucson, AZ 85721 USA. RI Lorenz, Ralph/B-8759-2016 OI Lorenz, Ralph/0000-0001-8528-4644 NR 51 TC 32 Z9 32 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 APR-MAY PY 2003 VL 51 IS 4-5 BP 353 EP 364 DI 10.1016/S0032-0633(02)00148-4 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 670NR UT WOS:000182415400007 ER PT J AU Delozier, DM Orwoll, RA Cahoon, JF Ladislaw, JS Smith, JG Connell, JW AF Delozier, DM Orwoll, RA Cahoon, JF Ladislaw, JS Smith, JG Connell, JW TI Polyimide nanocomposites prepared from high-temperature, reduced charge organoclays SO POLYMER LA English DT Article DE polyimide; nanocomposite; organoclay ID MECHANICAL-PROPERTIES; MONTMORILLONITE; CLAY; SORPTION AB Montmorillonite clays modified with the dihydrochloride salt of 1,3-bis(3-aminophenoxy)benzene (APB) were used in the preparation of polyimide/organoclay hybrid films. Organoclays with varying surface charge based upon APB were prepared and examined for their dispersion behavior in the polymer matrix. High molecular weight poly(amide acid) solutions were prepared in the presence of the organoclays. Films were cast and subsequently heated to 300 degreesC to cause imidization. The resulting nanocomposite films, containing 3 wt% of organoclay, were characterized by transmission electron microscopy and X-ray diffraction. The clay's cation exchange capacity (CEC) played a key role in determining the extent of dispersion in the polyimide matrix. Considerable dispersion was observed in some of the nanocomposite films. The most effective organoclay was found to have a CEC of 0.70 meq/g. Nanocomposite films prepared with 3-8 wt% of this organoclay were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), and thin-film tensile testing. High levels of clay dispersion could be achieved even at the higher clay loadings. Results from mechanical testing revealed that while the moduli of the nanocomposites increased with increasing clay loadings, both strength and elongation decreased. Published by Elsevier Science Ltd. C1 NASA, Langley Res Ctr, Adv Mat & Proc Branch, Hampton, VA 23681 USA. Coll William & Mary, Dept Chem, Williamsburg, VA 23187 USA. Coll William & Mary, Dept Appl Sci, Williamsburg, VA 23187 USA. RP Connell, JW (reprint author), NASA, Langley Res Ctr, Adv Mat & Proc Branch, Mail Stop 226, Hampton, VA 23681 USA. NR 24 TC 58 Z9 60 U1 3 U2 7 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0032-3861 J9 POLYMER JI Polymer PD APR PY 2003 VL 44 IS 8 BP 2231 EP 2241 DI 10.1016/S0032-3861(03)00082-X PG 11 WC Polymer Science SC Polymer Science GA 661XF UT WOS:000181914600006 ER PT J AU Rudy, RJ Venturini, CC Lynch, DK Mazuk, S Puetter, RC Perry, RB AF Rudy, RJ Venturini, CC Lynch, DK Mazuk, S Puetter, RC Perry, RB TI 0.8-2.5 micron reflectance spectroscopy of Pluto SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article ID CHARON; ICES; SURFACE; N-2; TRITON; SPECTROPHOTOMETRY; EVOLUTION; ALBEDO; WATER; FROST AB Near-infrared ( 0.8-2.5 mum) spectrophotometry, acquired on 2002 July 18.25, is presented for the Pluto-Charon system. The sub-Earth longitude and latitude of Pluto at the time of the observations were 80degrees and 28.degrees5, with a phase angle of 1.degrees25. The data span wavelength segments that are typically covered by different instruments and includes the seldom-observed 1-1.3 mum region. The geometric albedo is compared to previous observations that were close to this longitude, and no significant differences are seen. Wavelength shifts, relative to laboratory values for pure methane ice and methane immersed in N-2 ice, are reported for a number of methane features in Pluto's spectrum. C1 Aerosp Corp, Space Sci Applicat Lab, Los Angeles, CA 90009 USA. Univ Calif San Diego, Ctr Astrophys & Space Sci, La Jolla, CA 92093 USA. Pixon LLC, San Diego, CA 92123 USA. NASA, Earth & Space Sci Support Off, Langley Res Ctr, Hampton, VA 23681 USA. RP Rudy, RJ (reprint author), Aerosp Corp, Space Sci Applicat Lab, M2-266,POB 92957, Los Angeles, CA 90009 USA. EM richard.j.rudy@aero.org; catherine.c.venturini@aero.org; david.k.lynch@aero.org; stephan.m.mazuk@aero.org; rickpuetter@pixon.com; raleigh.b.perry@larc.nasa.gov NR 28 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 0004-6280 EI 1538-3873 J9 PUBL ASTRON SOC PAC JI Publ. Astron. Soc. Pac. PD APR PY 2003 VL 115 IS 806 BP 484 EP 489 DI 10.1086/374609 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 662WK UT WOS:000181971900006 ER PT J AU Shine, KP Bourqui, MS Forster, PMD Hare, SHE Langematz, U Braesicke, P Grewe, V Ponater, M Schnadt, C Smiths, CA Haighs, JD Austin, J Butchart, N Shindell, DT Randel, WJ Nagashima, T Portmann, RW Solomon, S Seidel, DJ Lanzante, J Klein, S Ramaswamy, V Schwarzkopf, MD AF Shine, KP Bourqui, MS Forster, PMD Hare, SHE Langematz, U Braesicke, P Grewe, V Ponater, M Schnadt, C Smiths, CA Haighs, JD Austin, J Butchart, N Shindell, DT Randel, WJ Nagashima, T Portmann, RW Solomon, S Seidel, DJ Lanzante, J Klein, S Ramaswamy, V Schwarzkopf, MD TI A comparison of model-simulated trends in stratospheric temperatures SO QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY LA English DT Article DE greenhouse gases; ozone depletion; stratospheric water vapour; temperature trends ID GENERAL-CIRCULATION MODEL; WATER-VAPOR; OZONE; CLIMATE; CHEMISTRY; PAST; INCREASES; GCM AB Estimates of annual-mean stratospheric temperature trends over the past twenty years, from a wide variety of models, are compared both with each other and with the observed cooling seen in trend analyses using radiosonde and satellite observations. The modelled temperature trends are driven by changes in ozone (either imposed from observations or calculated by the model), carbon dioxide and other relatively well-mixed greenhouse gases, and stratospheric water vapour. The comparison shows that whilst models generally simulate similar patterns in the vertical profile of annual-and global-mean temperature trends, there is a significant divergence in the size of the modelled trends, even when similar trace gas perturbations are imposed. Coupled-chemistry models are in as good agreement as models using imposed observed ozone trends, despite the extra degree of freedom that the coupled models possess. The modelled annual- and global-mean cooling of the upper stratosphere (near 1 hPa) is dominated by ozone and carbon dioxide changes, and is in reasonable agreement with observations. At about 5 hPa, the mean cooling from the models is systematically greater than that seen in the satellite data; however, for some models, depending on the size of the temperature trend due to stratospheric water vapour changes, the uncertainty estimates of the model and observations just overlap. Near 10 hPa there is good agreement with observations. In the lower stratosphere (20-70 hPa), ozone appears to be the dominant contributor to the observed cooling, although it does not, on its own, seem to explain the entire cooling. Annual- and zonal-mean temperature trends at 100 hPa and 50 hPa are also examined. At 100 hPa, the modelled cooling due to ozone depletion alone is in reasonable agreement with the observed cooling at all latitudes. At 50 hPa, however, the observed cooling at midlatitudes of the northern hemisphere significantly exceeds the modelled cooling due to ozone depletion alone. There is an indication of a similar effect in high northern latitudes, but the greater variability in both models and observations precludes a firm conclusion. The discrepancies between modelled and observed temperature trends in the lower stratosphere are reduced if the cooling effects of increased stratospheric water vapour concentration are included, and could be largely removed if certain assumptions were made regarding the size and distribution of the water vapour increase. However, given the uncertainties in the geographical extent of water vapour changes in the lower stratosphere, and the time period over which such changes have been sustained, other reasons for the discrepancy between modelled and observed temperature trends cannot be ruled out. C1 Univ Reading, Dept Meteorol, Reading RG6 6BB, Berks, England. Free Univ Berlin, D-1000 Berlin, Germany. Univ Cambridge, Dept Chem, Cambridge CB2 1TN, England. DLR, Oberpfaffenhofen, Germany. Univ London Imperial Coll Sci Technol & Med, London, England. Meteorol Off, Bracknell RB12 2SZ, Berks, England. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. Natl Inst Environm Studies, Ibaraki, Japan. NOAA, Aeron Lab, Boulder, CO 80303 USA. NOAA, Air Resources Lab, Silver Spring, MD 20910 USA. NOAA, Geophys Fluid Dynam Lab, Princeton, NJ USA. RP Shine, KP (reprint author), Univ Reading, Dept Meteorol, Earley Gate, Reading RG6 6BB, Berks, England. EM k.p.shine@reading.ac.uk RI Portmann, Robert/C-4903-2009; Shindell, Drew/D-4636-2012; Shine, Keith/D-9093-2012; Grewe, Volker/A-6147-2011; Braesicke, Peter/D-8330-2016; Klein, Stephen/H-4337-2016; Randel, William/K-3267-2016; Forster, Piers/F-9829-2010 OI Portmann, Robert/0000-0002-0279-6087; Shine, Keith/0000-0003-2672-9978; Grewe, Volker/0000-0002-8012-6783; Braesicke, Peter/0000-0003-1423-0619; Klein, Stephen/0000-0002-5476-858X; Randel, William/0000-0002-5999-7162; Forster, Piers/0000-0002-6078-0171 NR 39 TC 134 Z9 136 U1 1 U2 14 PU ROYAL METEOROLOGICAL SOC PI READING PA 104 OXFORD ROAD, READING RG1 7LJ, BERKS, ENGLAND SN 0035-9009 J9 Q J ROY METEOR SOC JI Q. J. R. Meteorol. Soc. PD APR PY 2003 VL 129 IS 590 BP 1565 EP 1588 DI 10.1256/QJ.02.186 PN A PG 24 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 673BT UT WOS:000182559900012 ER PT J AU Badhwar, GD Robbins, DE Gibbons, F Braby, LA AF Badhwar, GD Robbins, DE Gibbons, F Braby, LA TI Response of a tissue equivalent proportional counter to neutrons (vol 35, pg 551, 2002) SO RADIATION MEASUREMENTS LA English DT Correction C1 Texas A&M Univ, College Stn, TX 77843 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. USRA, Houston, TX USA. Lockheed Martin, Houston, TX USA. RP Braby, LA (reprint author), Texas A&M Univ, College Stn, TX 77843 USA. EM labraby@tamu.edu NR 1 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1350-4487 J9 RADIAT MEAS JI Radiat. Meas. PD APR PY 2003 VL 37 IS 2 BP 195 EP 195 DI 10.1016/S1350-4487(03)00002-7 PG 1 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 658TD UT WOS:000181735800014 ER PT J AU Kletetschka, G Zila, V Wasilewski, PJ AF Kletetschka, G Zila, V Wasilewski, PJ TI Magnetic anomalies on the tree trunks SO STUDIA GEOPHYSICA ET GEODAETICA LA English DT Article DE environment; pollution; soil; wood; iron oxides; hysteresis loops ID FOREST SOILS; POWER-PLANT; FLY-ASH; POLLUTION AB Magnetic measurements of soil and tree bark adjacent to a busy highway revealed a significant variation in the concentration of magnetic particles with distance from the highway. Further more, forest-facing tree-bark contains significantly more magnetic particles than road-facing tree-bark. Magnetic particles were detected both on the bark of the maple trees and in the first centimeter of the soil cover (O/A horizon). Stability of saturation isothermal magnetization (SIRM) and hysteresis parameters of the soil indicates the presence of single domain (SD/PSD) magnetic carriers. Measurements of the tree bark hysteresis parameters and SIRM detect a significant lower coercivity component that we interpret to be an indication of more abundant pseudo-single domain (PSD) type magnetic grains. Magnetic measurements around the perimeters of eight tree trunks reveal magnetic carriers whose distribution is antipodal to the source direction (highway). We interpret our observation by adopting an air circulation model, where suspended PSD/SD particles are carried in the air stream. The air stream from the heavy traffic lowers the amount of moisture on the tree trunk surfaces facing the highway and thus reduces an adhesive potential on this side. Therefore, more particles can stay on the moist side of the trunk protected from the direct airflow. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Howard Univ, Washington, DC 20059 USA. Charles Univ, Prague 12843 2, Czech Republic. RP Kletetschka, G (reprint author), NASA, Goddard Space Flight Ctr, Code 691, Greenbelt, MD 20771 USA. RI Kletetschka, Gunther/C-9996-2011 OI Kletetschka, Gunther/0000-0002-0645-9037 NR 16 TC 19 Z9 20 U1 1 U2 10 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0039-3169 J9 STUD GEOPHYS GEOD JI Stud. Geophys. Geod. PD APR PY 2003 VL 47 IS 2 BP 371 EP 379 DI 10.1023/A:1023779826177 PG 9 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 676FY UT WOS:000182741700008 ER PT J AU Moraru, L Keith, TG Dimofte, F Cioc, S Fleming, DP AF Moraru, L Keith, TG Dimofte, F Cioc, S Fleming, DP TI Dynamic modeling of a dual clearance squeeze film damper - Part I: Test rig and dynamic model with one damper SO TRIBOLOGY TRANSACTIONS LA English DT Article; Proceedings Paper CT 57th Annual Meeting of the Society-of-Tribologists-and-Lubrication-Engineers CY MAY 19-23, 2002 CL HOUSTON, TEXAS SP Soc Tribologists Lubricat Engn DE squeeze-film lubrication; dynamic modeling ID AIR ENTRAINMENT; COEFFICIENTS; CAVITATION AB This paper presents a description of a dual clearance squeeze film damper (SFD) test rig and a dynamic model of a single SFD. The purpose of a dual SFD is to provide protection at high levels of vibration, when conventional devices are no longer effective. An experimental facility was designed and built for the study of SFD behavior within mechanically controlled orbits. It can be used for both single and dual squeeze film dampers. In Part I of this paper, measured and computed responses are presented while operating as a single squeeze film device. Numerical and expert mental results for undamped cases are presented, i.e., when no oil film is present in the damper. Subsequently, the effects of the oil film are considered. Good agreement was obtained between experimental data and predictions. C1 Univ Toledo, Toledo, OH 43606 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Moraru, L (reprint author), Univ Toledo, 2801 W Bancroft St, Toledo, OH 43606 USA. NR 23 TC 8 Z9 13 U1 1 U2 4 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 840 BUSSE HIGHWAY, PARK RIDGE, IL 60068 USA SN 1040-2004 J9 TRIBOL T JI Tribol. Trans. PD APR PY 2003 VL 46 IS 2 BP 170 EP 178 DI 10.1080/10402000308982613 PG 9 WC Engineering, Mechanical SC Engineering GA 671ZY UT WOS:000182496800003 ER PT J AU Simpson, JJ Hufford, GL Servranckx, R Berg, J Pieri, D AF Simpson, JJ Hufford, GL Servranckx, R Berg, J Pieri, D TI Airborne Asian dust: case study of long-range transport and implications for the detection of volcanic ash SO WEATHER AND FORECASTING LA English DT Article ID OZONE MAPPING SPECTROMETER; SATELLITE-BASED TECHNIQUE; MINERAL AEROSOLS; ERUPTION CLOUD; SAHARAN DUST; APRIL 1998; ULTRAVIOLET; FAILURES; PACIFIC; HAZARD AB The transport of fine-grained Asian dust from its source (e.g., the Gobi Desert, Mongolia) to North America is a common springtime phenomenon. Because of its chemical composition (silicon, iron, aluminum, and calcium) and its particle size distribution (mean aerodynamic diameter 2-4 mum), Asian dust produces a negative signal in the split-window T-4 - T-5 algorithm, as does airborne volcanic ash. The split-window algorithm is commonly used by operational volcanic ash advisory centers. Thus, it is important to find ways to differentiate between airborne Asian dust and airborne volcanic ash. Use of Total Ozone Mapping Spectrometer aerosol and sulfur dioxide indices, in conjunction with the split-window method, can mitigate the possibility of a false airborne volcanic ash alarm. Asian dust also is important for other reasons. Thus, meteorological agencies should monitor it because 1) it can be transported thousands of kilometers from its source region and thus is of global interest (e.g., effects on radiative forcing) and 2) fine-grain particles pose a potentially serious public health hazard. C1 Univ Calif San Diego, Scripps Inst Oceanog, Digital Image Anal Lab, La Jolla, CA 92093 USA. Univ Alaska, Aviat Technol Ctr, Anchorage, AK USA. Meteorol Serv Canada, Canadian Meteorol Ctr, Montreal, PQ, Canada. CALTECH, Jet Prop Lab, Pasadena, CA USA. RP Simpson, JJ (reprint author), Univ Calif San Diego, Scripps Inst Oceanog, Digital Image Anal Lab, La Jolla, CA 92093 USA. NR 53 TC 18 Z9 18 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD APR PY 2003 VL 18 IS 2 BP 121 EP 141 DI 10.1175/1520-0434(2003)018<0121:AADCSO>2.0.CO;2 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 671EL UT WOS:000182452300001 ER PT J AU Ng, HT Chen, B Li, J Han, JE Meyyappan, M Wu, J Li, SX Haller, EE AF Ng, HT Chen, B Li, J Han, JE Meyyappan, M Wu, J Li, SX Haller, EE TI Optical properties of single-crystalline ZnO nanowires on m-sapphire SO APPLIED PHYSICS LETTERS LA English DT Article ID GROWTH; ARRAYS; FILMS; PHOTOLUMINESCENCE; FABRICATION; DEPOSITION; EPITAXY AB ZnO nanowires have been synthesized using a catalyst-assisted heteroepitaxial carbothermal reduction approach on a m-sapphire substrate. Intricate and uniform arrays have been obtained with each nanowire forming an angle similar to30degrees with the substrate normal. Photoluminescence studies at room temperature for wavelengths between 335 and 620 nm reveal a strong single exciton peak at similar to380 nm (3.26 eV) with accompanying deep-level blueshifted emission peaks at similar to486, 490, and 510 nm. UV resonant Raman spectroscopy has been used to characterize the nanowires at room temperature with multiphonon scattering exhibiting phonon quantum confinement. (C) 2003 American Institute of Physics. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. ELORET Corp, Sunnyvale, CA USA. RP Ng, HT (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM hng@mail.arc.nasa.gov RI Wu, Junqiao/G-7840-2011; Li, Jun/H-7771-2013 OI Wu, Junqiao/0000-0002-1498-0148; Li, Jun/0000-0002-3689-8946 NR 22 TC 247 Z9 258 U1 3 U2 45 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 MAR 31 PY 2003 VL 82 IS 13 BP 2023 EP 2025 DI 10.1063/1.1564870 PG 3 WC Physics, Applied SC Physics GA 659WU UT WOS:000181801100009 ER PT J AU Ma, J Waugh, DW Douglass, AR Kawa, SR Lin, SJ AF Ma, J Waugh, DW Douglass, AR Kawa, SR Lin, SJ TI Evaluation of the transport in the Goddard Space Flight Center three-dimensional chemical transport model using the equivalent length diagnostic SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE modified Lagrangian mean; equivalent length; CLAES; chemical transport model; transport; mixing ID STRATOSPHERIC POLAR VORTICES; ARRAY ETALON SPECTROMETER; LAGRANGIAN-MEAN DIAGNOSTICS; GENERAL-CIRCULATION MODEL; EFFECTIVE DIFFUSIVITY; MIDDLE ATMOSPHERE; CLIMATOLOGY; VARIABILITY; SIMULATION; OZONE AB [1] Transport and mixing in the extratropical stratosphere of the NASA Goddard Space Flight Center (GSFC) three-dimensional (3-D) chemical transport model (CTM) are evaluated using the modified Lagrangian-mean diagnostic. The normalized equivalent length squared (xi) has been calculated from simulated N2O and CH4 distributions using two different wind data sets and has been compared with that calculated from observations by the CLAES satellite instrument. There is generally good agreement, indicating that the CTM realistically simulates the location and seasonal evolution of mixing regions/barriers in the extratropical lower and middle stratosphere. Differences that occur between the CTM fields and observations at high latitudes in winter and spring can be attributed to interannual variability in polar meteorology. There are also some differences in northern summer: the CTM series shows regions of high xi in the extratropics that are not observed in xi from CLAES. These high values occur where there is small-scale variability in N2O in regions with very weak meridional gradients. Comparison of xi from isentropic tracer simulations using the same wind fields as used in the 3-D CTM show good agreement except during the summer. The isentropic tracers do not have as much small-scale variability as the 3-D CTM tracer fields, indicating that the enhanced small-scale structures in the CTM N2O, and high values of xi, are produced by small-scale horizontal variability in the vertical motions. The fact that vertical motions can influence summer values of xi means that these xi fields cannot be interpreted in terms of quasi-horizontal mixing. C1 Johns Hopkins Univ, Dept Earth & Planetary Sci, Baltimore, MD 21218 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Ma, J (reprint author), Johns Hopkins Univ, Dept Earth & Planetary Sci, 3400 N Charles St, Baltimore, MD 21218 USA. EM junma@rua.eps.jhu.edu; waugh@jhu.edu; douglass@persephone.gsfc.nasa.gov; kawa@maya.gsfc.nasa.gov RI Douglass, Anne/D-4655-2012; Kawa, Stephan/E-9040-2012; Waugh, Darryn/K-3688-2016 OI Waugh, Darryn/0000-0001-7692-2798 NR 35 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 MAR 29 PY 2003 VL 108 IS D6 AR 4201 DI 10.1029/2002JD002268 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 677QD UT WOS:000182818300004 ER PT J AU Thejappa, G MacDowall, RJ Scime, EE Littleton, JE AF Thejappa, G MacDowall, RJ Scime, EE Littleton, JE TI Evidence for electrostatic decay in the solar wind at 5.2 AU SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE Langmuir waves; ion-acoustic waves; electrostatic decay; Ulysses ID BEAM-PLASMA INSTABILITY; CLUMPY LANGMUIR-WAVES; III RADIO-BURST; EMISSION MECHANISMS; DENSITY-FLUCTUATIONS; STRONG TURBULENCE; EARTHS FORESHOCK; MAGNETIC HOLES; DYNAMICS; ELECTRONS AB [1] The Unified Radio and Plasma wave Experiment (URAP) on the Ulysses spacecraft provides in situ observations of Langmuir waves and ion-acoustic waves in the solar wind. The observations presented in this paper were obtained at 5.2 AU from the Sun. Low-frequency (20-200 Hz in the spacecraft frame) electric field signals are observed coincident in time with the most intense Langmuir waves. The low-frequency wave signals are identified as long-wavelength ion-acoustic waves. These observations provide evidence for the decay of Langmuir waves into daughter Langmuir and ion-acoustic waves (the electrostatic decay process) in the solar wind. C1 Univ Maryland, Dept Astron, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. W Virginia Univ, Dept Phys, Morgantown, WV 26506 USA. RP Thejappa, G (reprint author), Univ Maryland, Dept Astron, College Pk, MD 20742 USA. RI MacDowall, Robert/D-2773-2012 NR 35 TC 16 Z9 16 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 MAR 28 PY 2003 VL 108 IS A3 AR 1139 DI 10.1029/2002JA009290 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 677QY UT WOS:000182820100001 ER PT J AU Tsyganenko, NA Mukai, T AF Tsyganenko, NA Mukai, T TI Tail plasma sheet models derived from Geotail particle data SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE plasma sheet; solar wind; modeling; ion pressure; density; temperature ID MAGNETOSPHERIC MAGNETIC-FIELD; SOLAR-WIND; MAGNETOPAUSE; TEMPERATURE; PRESSURE; DENSITY AB [1] Simple analytical models have been derived for the first time, describing the 2-D distribution (along and across the Earth's magnetotail) of the central plasma sheet (CPS) ion temperature, density, and pressure, as functions of the incoming solar wind and interplanetary magnetic field (IMF) parameters, at distances between 10 and 50 R-E. The models are based on a large set of data of the Low-Energy Particle (LEP) and Magnetic Field (MGF) instruments, taken by Geotail spacecraft between 1994 and 1998, comprising 7234 1-min average values of the CPS temperature and density. Concurrent solar wind and IMF data were provided by the Wind and IMP 8 spacecraft. The accuracy of the models was gauged by the correlation coefficient (c.c.) R between the observed and predicted values of a parameter. The CPS ion density N is controlled mostly by the solar wind proton density and by the northward component of the IMF. Being the least stable characteristic of the CPS, it yielded the lowest c.c. R-N = 0.57. The CPS temperature T, controlled mainly by the solar wind speed V and the IMF B-z, gave a higher c.c. R-T = 0.71. The CPS ion pressure P was best controlled by the solar wind ram pressure P-sw and by an IMF-related parameter F = B(perpendicular to)rootsin(theta/2), where B-perpendicular to is the perpendicular component of the IMF and theta is its clock angle. In a striking contrast with N and T, the model pressure P revealed a very high c.c. with the data, R-P = 0.95, an apparent consequence of the force balance between the CPS and the tail lobe magnetic field. No significant dawn-dusk asymmetry of the CPS was found beyond the distance 10 R-E, in line with the observed symmetry of the tail lobe magnetic field. The plasma density N is lowest at midnight and increases toward the tail's flanks. Larger (smaller) solar wind ion densities and northward (southward) IMF B-z result in larger (smaller) N in the CPS. In contrast to the density N, the temperature T peaks at the midnight meridian and falls off toward the dawn/dusk flanks. Faster (slower) solar wind flow and southward (northward) IMF B-z result in a hotter (cooler) CPS. The CPS ion pressure P is essentially a function of only X-GSM in the midtail (20-50 R-E); at closer distances the isobars gradually bend to approximately follow the contours of constant geomagnetic field strength. For northward IMF conditions combined with a slow solar wind, the isobars remain quasi-circular up to larger distances, reflecting a weaker tail current and, hence, more dipole-like magnetic field. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, USRA, Greenbelt, MD 20771 USA. Inst Space & Astronaut Sci, Kanagawa 2298510, Japan. RP Tsyganenko, NA (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, USRA, Code 695, Greenbelt, MD 20771 USA. RI Tsyganenko, Nikolai/J-7377-2012 OI Tsyganenko, Nikolai/0000-0002-5938-1579 NR 23 TC 122 Z9 122 U1 1 U2 8 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD MAR 28 PY 2003 VL 108 IS A3 AR 1136 DI 10.1029/2002JA009707 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 677QY UT WOS:000182820100004 ER PT J AU Alley, RB Marotzke, J Nordhaus, WD Overpeck, JT Peteet, DM Pielke, RA Pierrehumbert, RT Rhines, PB Stocker, TF Talley, LD Wallace, JM AF Alley, RB Marotzke, J Nordhaus, WD Overpeck, JT Peteet, DM Pielke, RA Pierrehumbert, RT Rhines, PB Stocker, TF Talley, LD Wallace, JM TI Abrupt climate change SO SCIENCE LA English DT Review ID THERMOHALINE CIRCULATION; NORTH-ATLANTIC; OCEAN; VARIABILITY; HOLOCENE; EVENT; STABILIZATION; CIVILIZATION; TEMPERATURE; SIMULATION AB Large, abrupt, and widespread climate changes with major impacts have occurred repeatedly in the past, when the Earth system was forced across thresholds. Although abrupt climate changes can occur for many reasons, it is conceivable that human forcing of climate change is increasing the probability of large, abrupt events. Were such an event to recur, the economic and ecological impacts could be large and potentially serious. Unpredictability exhibited near climate thresholds in simple models shows that some uncertainty will always be associated with projections. In light of these uncertainties, policy-makers should consider expanding research into abrupt climate change, improving monitoring systems, and taking actions designed to enhance the adaptability and resilience of ecosystems and economies. C1 Penn State Univ, Dept Geosci, University Pk, PA 16802 USA. Penn State Univ, EMS Environm Inst, University Pk, PA 16802 USA. Univ Southampton, Southampton Oceanog Ctr, Southampton SO14 3ZH, Hants, England. Yale Univ, Dept Econ, New Haven, CT 06520 USA. Univ Arizona, Inst Study Planet Earth, Tucson, AZ 85721 USA. Columbia Univ, Lamont Doherty Earth Observ, Palisades, NY 10964 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Univ Colorado, Ctr Sci & Technol Policy Res, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. Univ Chicago, Dept Geophys Sci, Chicago, IL 60637 USA. Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. Univ Washington, Dept Oceanog, Seattle, WA 98195 USA. Univ Bern, Inst Phys, CH-3012 Bern, Switzerland. Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. RP Alley, RB (reprint author), Penn State Univ, Dept Geosci, University Pk, PA 16802 USA. RI Stocker, Thomas/B-1273-2013; OI Pierrehumbert, Raymond/0000-0002-5887-1197 NR 63 TC 518 Z9 556 U1 17 U2 199 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 MAR 28 PY 2003 VL 299 IS 5615 BP 2005 EP 2010 DI 10.1126/science.1081056 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 660LG UT WOS:000181834200034 PM 12663908 ER PT J AU Thomason, LW Herber, AB Yamanouchi, T Sato, K AF Thomason, LW Herber, AB Yamanouchi, T Sato, K TI Arctic study on tropospheric aerosol and radiation: comparison of tropospheric aerosol extinction profiles measured by airborne photometer and SAGE II SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB The Arctic Study on Tropospheric Aerosol and Radiation (ASTAR) is focused on understanding the climate effects of Arctic haze. As a part of this experiment, a tropospheric aerosol extinction profile was obtained by airborne sun photometer spatially and temporally close to a satellite-based measurement. The results suggest that airborne photometry is a promising avenue for the validation of satellite-derived aerosol extinction measurements in the middle and upper troposphere. The results also suggest that SAGE II measurements can be used to provide a regional context to more intensive but spatially limited aircraft and ground-based data sets. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Fdn Polar & Marine Res, Alfred Wegener Inst Polar & Marine Res, D-27570 Bremerhaven, Germany. Natl Inst Polar Res, Itabashi Ku, Tokyo 1738515, Japan. RP Thomason, LW (reprint author), NASA, Langley Res Ctr, Mail Stop 475, Hampton, VA 23681 USA. RI Yamanouchi, Takashi/P-2041-2015; Satoh, Kaoru/P-2047-2015; OI Sato, Kaoru/0000-0002-6225-6066 NR 11 TC 10 Z9 12 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 MAR 27 PY 2003 VL 30 IS 6 AR 1328 DI 10.1029/2002GL016453 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 677PU UT WOS:000182817400004 ER PT J AU Petkov, MP Wang, CL Weber, MH Lynn, KG Rodbell, KP AF Petkov, MP Wang, CL Weber, MH Lynn, KG Rodbell, KP TI Positron annihilation techniques suited for porosity characterization of thin films SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID NUMERICAL LAPLACE INVERSION; ON-GLASS-FILMS; PORE-SIZE; LIFETIME SPECTRA; AMORPHOUS POLYMERS; SURFACES; DISTRIBUTIONS; SPECTROSCOPY; DIFFUSION; PROGRAM AB The porosity in thin (similar to1 mum) mesoporous low dielectric constant (low-k) films is investigated by different beam-based positron annihilation spectroscopy (PAS) techniques. Examples are given for mesoporous methylsilsesquioxane films deposited with a sacrificial polymer (porogen, from 0 to 90 wt % load) and subsequently annealed to drive out the volatile porogen, resulting in films with nanometer size voids. The important features of positronium (Ps; an electron -positron atom-like bound state) interaction with porous materials (formation, confinement, diffusion, thermalization, and annihilation) are highlighted. Ps was identified as an especially suitable probe for identifying open porosity, manifested by Ps escape in a vacuum. Three-photon (3gamma) PAS was utilized to derive the length-scale for pore interconnectivity prior to total percolation, and open porosity fraction as a function of the porogen load. Lifetime spectroscopy (PALS) was used to obtain the pore size distribution, and the Ps energy is assessed using the momentum-sensitive PAS techniques. For the mesoporous low-k films, these two complementary techniques yield the vast majority of the porosity properties assessable by PAS. The necessity for future improvements in the PAS analysis, as well as a broad-scale comparison with other diagnostic techniques is discussed. C1 Washington State Univ, Dept Phys, Pullman, WA 99164 USA. IBM Corp, Thomas J Watson Res Ctr, Yorktown Hts, NY 10598 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. OI Wang, Cai-Lin/0000-0001-9745-2334 NR 57 TC 40 Z9 42 U1 1 U2 20 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1520-6106 J9 J PHYS CHEM B JI J. Phys. Chem. B PD MAR 27 PY 2003 VL 107 IS 12 BP 2725 EP 2734 DI 10.1021/jp013947b PG 10 WC Chemistry, Physical SC Chemistry GA 658JJ UT WOS:000181717600015 ER PT J AU Harreld, JH Sakamoto, J Dunn, B AF Harreld, JH Sakamoto, J Dunn, B TI Non-hydrolytic sol-gel synthesis and electrochemical characterization of tin-based oxide aerogels SO JOURNAL OF POWER SOURCES LA English DT Article ID SECONDARY LITHIUM BATTERIES; LI-ION BATTERIES; THIN-FILMS; SNO2; CHEMISTRY; ANODES; COMPOSITES; DEPOSITION; REDUCTION; MONOLITH AB A non-hydrolytic sol-gel approach was utilized to create tin oxide and tin-aluminum binary oxide aerogels with high porosity (90%) and high surface area (300 m(2)/g). XRD data from single-phase tin oxide aerogel indicates the growth of SnO2 crystallites between 150 and 400 degreesC in air, accompanied by a substantial reduction in surface area. Heated tin oxide aerogel exhibits comparable reversible specific capacity (390 mAh/g) comparable to that of a commercially obtained SnO2 reference (420 mAh/g). By mixing tin and aluminum precursors, binary oxide aerogels were created in which the crystal growth of tin oxide domains was suppressed until higher temperatures. The tin oxide phase in this mixed system remains electrochemically active towards lithium insertion and exhibits excellent reversibility during cycling. (C) 2003 Elsevier Science B.V. All rights reserved. C1 Univ Calif Santa Barbara, Dept Chem, Santa Barbara, CA 93106 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif Los Angeles, Dept Mat Sci & Engn, Los Angeles, CA 90095 USA. RP Harreld, JH (reprint author), Univ Calif Santa Barbara, Dept Chem, Santa Barbara, CA 93106 USA. NR 51 TC 22 Z9 23 U1 5 U2 23 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 MAR 27 PY 2003 VL 115 IS 1 BP 19 EP 26 DI 10.1016/S0378-7753(02)00626-2 PG 8 WC Chemistry, Physical; Electrochemistry; Energy & Fuels; Materials Science, Multidisciplinary SC Chemistry; Electrochemistry; Energy & Fuels; Materials Science GA 663KM UT WOS:000182004800003 ER PT J AU Bidigare, RR Benitez-Nelson, C Leonard, CL Quay, PD Parsons, ML Foley, DG Seki, MP AF Bidigare, RR Benitez-Nelson, C Leonard, CL Quay, PD Parsons, ML Foley, DG Seki, MP TI Influence of a cyclonic eddy on microheterotroph biomass and carbon export in the lee of Hawaii SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID VOLUME; SEAWATER; WATERS; OCEAN; SEA AB A multi-platform sampling strategy was used to investigate carbon cycling in a cold-core eddy that formed in the lee of Hawaii during September 2000. Micro-heterotroph biomass and Th-234-derived carbon export rates within the eddy were 2 to 3 times higher than those observed for adjacent waters. If this eddy is representative of other cyclonic eddies that are frequently formed in the lee of Hawaii, then eddy activity may significantly enhance the areal efficiency of the biological pump and facilitate the transfer of organic carbon to organisms inhabiting the mesopelagic and abyssal-benthic zones of this subtropical ecosystem. C1 Univ Hawaii Manoa, Sch Ocean & Earth Sci & Technol, Dept Oceanog, Honolulu, HI 96822 USA. Univ Washington, Sch Oceanog, Seattle, WA 98195 USA. Univ Hawaii, Div Nat Sci, Dept Marine Sci, Hilo, HI 96720 USA. Univ Hawaii Manoa, Sch Ocean & Earth Sci & Technol, Joint Inst Marine & Atmospher Res, Honolulu, HI 96822 USA. Natl Marine Fisheries Serv, NOAA, SW Fisheries Sci Ctr, Honolulu Lab, Honolulu, HI 96822 USA. RP Bidigare, RR (reprint author), Univ Hawaii Manoa, Sch Ocean & Earth Sci & Technol, Dept Oceanog, Honolulu, HI 96822 USA. NR 19 TC 40 Z9 40 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 MAR 26 PY 2003 VL 30 IS 6 AR 1318 DI 10.1029/2002GL016393 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 677PT UT WOS:000182817300006 ER PT J AU Novakov, T Ramanathan, V Hansen, JE Kirchstetter, TW Sato, M Sinton, JE Sathaye, JA AF Novakov, T Ramanathan, V Hansen, JE Kirchstetter, TW Sato, M Sinton, JE Sathaye, JA TI Large historical changes of fossil-fuel black carbon aerosols SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID TROPICAL INDIAN-OCEAN; UNITED-STATES; FINE-PARTICLE; EMISSIONS; CLIMATE; SURFACE; SULFUR; ATMOSPHERE; BIOMASS; TRENDS AB Anthropogenic emissions of fine black carbon (BC) particles, the principal light-absorbing atmospheric aerosol, have varied during the past century in response to changes of fossil-fuel utilization, technology developments, and emission controls. We estimate historical trends of fossil-fuel BC emissions in six regions that represent about two-thirds of present day emissions and extrapolate these to global emissions from 1875 onward. Qualitative features in these trends show rapid increase in the latter part of the 1800s, the leveling off in the first half of the 1900s, and the re-acceleration in the past 50 years as China and India developed. We find that historical changes of fuel utilization have caused large temporal change in aerosol absorption, and thus substantial change of aerosol single scatter albedo in some regions, which suggests that BC may have contributed to global temperature changes in the past century. This implies that the BC history needs to be represented realistically in climate change assessments. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Environm Energy Technol Div, Berkeley, CA 94720 USA. Univ Calif San Diego, Scripps Inst Oceanog, Ctr Atmospher Sci, La Jolla, CA 92093 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Novakov, T (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Environm Energy Technol Div, Berkeley, CA 94720 USA. NR 28 TC 139 Z9 149 U1 1 U2 27 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 MAR 26 PY 2003 VL 30 IS 6 AR 1324 DI 10.1029/2002GL016345 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 677PT UT WOS:000182817300003 ER PT J AU Zhao, TXP Laszlo, I Dubovik, O Holben, BN Sapper, J Tanre, D Pietras, C AF Zhao, TXP Laszlo, I Dubovik, O Holben, BN Sapper, J Tanre, D Pietras, C TI A study of the effect of non-spherical dust particles on the AVHRR aerosol optical thickness retrievals SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID TROPOSPHERIC AEROSOLS; SIZE DISTRIBUTION; LIGHT-SCATTERING; SATELLITE; CLIMATE; VALIDATION AB Non-spherical assumption of particle shape has been used to replace the spherical assumption in the AVHRR aerosol optical thickness (tau) retrievals for dust particles. Retrieved tau with both spherical and non-spherical assumptions have been compared to the surface AERONET observations at two desert dust sites to evaluate and quantify the effect of non-spherical dust particles on the satellite aerosol retrievals. The errors ( especially the random error) in the satellite retrieved t have been reduced as a result of adopting the non-spherical assumption in the NOAA/NESDIS AVHRR aerosol retrieval algorithm. This result suggests the importance of taking into account the effects of non-sphericity in the retrieval of dust particles from AVHRR measurements. C1 Colorado State Univ, Cooperat Inst Res Atmosphere, Ft Collins, CO 80523 USA. Natl Environm Satellite Data & Informat Serv, NOAA, ORA, Camp Springs, MD 20746 USA. Sci Syst & Applicat Inc, Lanham, MD 20771 USA. NASA, Terr Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Natl Environm Satellite Data & Informat Serv, NOAA, OSDPD, Suitland, MD 20746 USA. Univ Sci & Tech Lille Flandres Artois, Lille, France. NASA, SAIC, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Colorado State Univ, Cooperat Inst Res Atmosphere, Foothills Campus, Ft Collins, CO 80523 USA. EM Xuepeng.Zhao@noaa.gov RI Dubovik, Oleg/A-8235-2009; Laszlo, Istvan/F-5603-2010 OI Dubovik, Oleg/0000-0003-3482-6460; Laszlo, Istvan/0000-0002-5747-9708 NR 18 TC 21 Z9 22 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAR 26 PY 2003 VL 30 IS 6 AR 1317 DI 10.1029/2002GL016379 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 677PT UT WOS:000182817300004 ER PT J AU Gatebe, CK King, MD Platnick, S Arnold, GT Vermote, EF Schmid, B AF Gatebe, CK King, MD Platnick, S Arnold, GT Vermote, EF Schmid, B TI Airborne spectral measurements of surface-atmosphere anisotropy for several surfaces and ecosystems over southern Africa SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE BRDF; SAFARI 2000; surface reflectance; airborne measurements; radiometer; multispectral ID AEROSOL OPTICAL-PROPERTIES; SKY RADIANCE MEASUREMENTS; KUWAIT OIL-FIRE; BIDIRECTIONAL REFLECTANCE; ALBEDO; LAND; VEGETATION; RETRIEVAL; CLOUDS; SENSITIVITY AB [1] The Cloud Absorption Radiometer (CAR) was flown aboard the University of Washington Convair CV-580 research aircraft during the Southern Africa Regional Science Initiative 2000 (SAFARI 2000) dry season campaign and obtained measurements of bidirectional reflectance distribution function (BRDF) for a variety of natural surfaces and ecosystems in southern Africa. To measure the BRDF of the surface-atmosphere system, the University of Washington CV-580 banked at a roll angle of similar to20degrees and flew circles about 3 km in diameter above the surface, taking approximately 2 min. Multiple circular orbits were acquired over selected surfaces so that average BRDFs could be acquired, smoothing out small-scale surface and atmospheric inhomogeneities. In this paper, we present results of BRDFs taken over two Earth Observing System (EOS) validation sites: Skukuza tower, South Africa (25.0degreesS, 31.5degreesE) and Mongu tower, Zambia (15.4degreesS, 23.3degreesE). Additional sites are discussed and include the Maun tower, Botswana (20.0degreesS, 23.6degreesE), Sua Pan, Botswana (20.6degreesS, 25.9degreesE), Etosha Pan, Namibia (19.0degreesS, 16.0degreesE), and marine stratocumulus clouds off the west coast of Namibia (20.5degreesS, 13.1degreesE). Results clearly show anisotropy in reflected solar radiation over the various surfaces types: savanna, salt pans, and cloud. The greatest anisotropy is observed over marine stratus clouds, which exhibit strong forward scattering as well as important water cloud scattering features such as the rainbow and glory. The BRDF over savanna is characterized by a distinct backscattering peak in the principal plane and shows directional and spectral variations. Over the pans, the BRDF is more enhanced in the backscattering plane than forward scattering plane and shows little directional variation. C1 Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. NASA, Earth Sci Directorate, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EER Commun Syst Inc, L3 Commun, Chantilly, VA USA. Univ Maryland, Dept Geog, College Pk, MD 20742 USA. Bay Area Environm Res Inst, Sonoma, CA USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. EM gatebe@climate.gsfc.nasa.gov; michael.d.king@nasa.gov; steven.e.platnick@nasa.gov; arnold@climate.gsfc.nasa.gov; eric@kratmos.gsfc.nasa.gov; bschmid@mail.arc.nasa.gov RI King, Michael/C-7153-2011; Gatebe, Charles/G-7094-2011; Vermote, Eric/K-3733-2012; Platnick, Steven/J-9982-2014 OI King, Michael/0000-0003-2645-7298; Gatebe, Charles/0000-0001-9261-2239; Platnick, Steven/0000-0003-3964-3567 NR 50 TC 35 Z9 35 U1 2 U2 11 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 MAR 25 PY 2003 VL 108 IS D13 AR 8489 DI 10.1029/2002JD002397 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 677QH UT WOS:000182818700001 ER PT J AU Dorelli, JC Birn, J AF Dorelli, JC Birn, J TI Whistler-mediated magnetic reconnection in large systems: Magnetic flux pileup and the formation of thin current sheets SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE magnetic reconnection; MHD simulation; computational plasma physics ID ELECTRON MAGNETOHYDRODYNAMICS; COLLISIONLESS RECONNECTION; COALESCENCE INSTABILITY; SUDDEN ENHANCEMENT; CHALLENGE; SIMULATIONS; PRESSURE; ISLANDS; GROWTH; MODELS AB [1] We compute numerical solutions of the resistive Hall MHD equations corresponding to pairwise magnetic island coalescence. The simulation results can be organized according to the relative sizes of three length scales: the electron dissipation length, l(e); the ion inertial length, d(i); and the island wavelength, lambda. We identify three qualitatively distinct regimes of magnetic island coalescence: (1) the resistive MHD limit, d(i) less than or similar to l(e) << lambda; (2) the "whistler-mediated'' limit, l(e) << d(i) << lambda; and (3) the "whistler-driven'' limit, l(e) << lambda less than or similar to d(i). In the resistive MHD limit, magnetic flux piles up outside thin current sheets between the islands. The upstream Alfven speed increases with increasing Lundquist number, and the reconnection rate is insensitive to the Lundquist number. In the whistler-driven limit, the electron and ion bulk flows decouple on the island wavelength scale. Magnetic flux pileup does not occur, and the coalescence proceeds on a whistler timescale that is much shorter than the Alfven time. In the whistler-mediated limit, electron and ion bulk flows decouple in spatially localized "ion inertial sheets'' around the island separatrices. Flux pileup is reduced, and the upstream Alfven speed approaches a nearly constant value as the Lundquist number is increased. The maximum reconnection rate in the whistler-mediated limit is comparable to that observed in the resitive MHD limit over the Lundquist number range 500 < S-λ < 10000. C1 Los Alamos Natl Lab, Space & Atmospher Sci Grp, Los Alamos, NM 87545 USA. RP Dorelli, JC (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Electrodynam Branch, Code 696, Greenbelt, MD 20771 USA. RI Dorelli, John/C-9488-2012 NR 39 TC 44 Z9 45 U1 0 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD MAR 25 PY 2003 VL 108 IS A3 AR 1133 DI 10.1029/2001JA009180 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 677QW UT WOS:000182819900001 ER PT J AU Jain, M Majumder, SB Katiyar, RS Miranda, FA Van Keuls, FW AF Jain, M Majumder, SB Katiyar, RS Miranda, FA Van Keuls, FW TI Improvement in electrical characteristics of graded manganese doped barium strontium titanate thin films SO APPLIED PHYSICS LETTERS LA English DT Article ID DIELECTRIC-PROPERTIES; PHASE-TRANSITIONS; LEAKAGE CURRENT; BEHAVIOR AB Highly (100) textured graded manganese (Mn) doped Ba0.5Sr0.5TiO3 [BST (50/50)] thin films were deposited on lanthanum aluminate substrates using sol-gel technique. We have demonstrated that the graded acceptor doping is a promising technique to reduce the temperature coefficient of capacitance (TCC), loss tangent, and leakage current of BST thin films. In the temperature range between 175 and 260 K the reported TCC of Mn graded BST (50/50) films is less than 5.55x10(-4)/K, which is comparable to the best capacitors known so far. The lower temperature coefficient of the capacitance of the Mn graded films has been argued to be due to the induced compositional heterogeneity resulting into a distribution of the Curie temperature. (C) 2003 American Institute of Physics. C1 Univ Puerto Rico, Dept Phys, San Juan, PR 00931 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Katiyar, RS (reprint author), Univ Puerto Rico, Dept Phys, San Juan, PR 00931 USA. OI Jain, Menka/0000-0002-2264-6895 NR 22 TC 98 Z9 107 U1 3 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 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAR 24 PY 2003 VL 82 IS 12 BP 1911 EP 1913 DI 10.1063/1.1560861 PG 3 WC Physics, Applied SC Physics GA 657KX UT WOS:000181666500035 ER PT J AU Shapiro, BE Levchenko, A Meyerowitz, EM Wold, BJ Mjolsness, ED AF Shapiro, BE Levchenko, A Meyerowitz, EM Wold, BJ Mjolsness, ED TI Cellerator: extending a computer algebra system to include biochemical arrows for signal transduction simulations SO BIOINFORMATICS LA English DT Article AB Cellerator describes single and multi-cellular signal transduction networks (STN) with a compact, optionally palette-driven, arrow-based notation to represent biochemical reactions and transcriptional activation. Multicompartment systems are represented as graphs with STNs embedded in each node. Interactions include mass-action, enzymatic, allosteric and connectionist models. Reactions are translated into differential equations and can be solved numerically to generate predictive time courses or output as systems of equations that can be read by other programs. Cellerator simulations are fully extensible and portable to any operating system that supports Mathematica, and can be indefinitely nested within larger data structures to produce highly scaleable models. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Johns Hopkins Univ, Dept Biomed Engn, Baltimore, MD 21218 USA. CALTECH, Div Biol, Pasadena, CA 91125 USA. Univ Calif Irvine, Dept Informat & Comp Sci, Irvine, CA 92647 USA. RP Shapiro, BE (reprint author), CALTECH, Jet Prop Lab, Mail Stop 126-347,4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Meyerowitz, Elliot/A-7118-2009 NR 2 TC 67 Z9 71 U1 0 U2 3 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 1367-4803 J9 BIOINFORMATICS JI Bioinformatics PD MAR 22 PY 2003 VL 19 IS 5 BP 677 EP 678 DI 10.1093/bioinformatics/btg042 PG 2 WC Biochemical Research Methods; Biotechnology & Applied Microbiology; Computer Science, Interdisciplinary Applications; Mathematical & Computational Biology; Statistics & Probability SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Computer Science; Mathematical & Computational Biology; Mathematics GA 662TN UT WOS:000181964600027 PM 12651737 ER PT J AU Ostgaard, N Detrick, DL Rosenberg, TJ Vondrak, RR Frey, HU Mende, SB Haland, SE Stadsnes, J AF Ostgaard, N Detrick, DL Rosenberg, TJ Vondrak, RR Frey, HU Mende, SB Haland, SE Stadsnes, J TI High-latitude dayside energetic precipitation and IMF B-Z rotations SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE magnetopause; cusp; boundary layers; auroral ionosphere; solar wind/magnetosphere interactions ID INTERPLANETARY MAGNETIC-FIELD; PARTICLE-PRECIPITATION; IONOSPHERIC SIGNATURES; ELECTRON-PRECIPITATION; AURORAL EMISSIONS; CURRENT SYSTEM; SOUTH-POLE; MAGNETOPAUSE; CUSP; CONVECTION AB [1] X-ray images from space and optical and riometer data from the ground are used to examine two discrete high-latitude dayside arcs. The dayside auroral oval is usually associated with soft precipitation of less than or equal to1 keV electrons but the observed X-ray features and riometer data indicate more energetic precipitation as the X-rays are produced by electrons with energies >2.5 keV and cosmic radio absorption is associated with similar to10 keV electron precipitation. Both the X-ray images from space as well as the ground based optical and riometer data show two energetic precipitation events appearing at high latitudes and subsequently moving equatorward at similar to0.5 km/s. The average energy of the electrons is estimated to be 4-8 keV, and the energy deposition is 6-10 mW/m(2). Owing to the high latitudes it is unlikely that these electrons were energized on the nightside and adiabatically drifted to the dayside. Instead, we think that the high-latitude events are controlled by the solar wind. The precipitation appears at similar to77-79degrees magnetic latitude and coincides with a northward turning of the interplanetary field. Owing to the uncertainties in determining the exact location of open-closed boundary we interpret the events to be caused by either KH instabilities at the inner edge of the LLBL or by lobe reconnection. In the latter case the arcs are produced by electrons accelerated by parallel electric fields resulting from converging horizontal electric fields associated with convection enhancements due to lobe reconnection at the front surface of the magnetotail. These flux tubes map to the poleward edge of the cusp. The equatorward movement is attributed to erosion of field lines as the interplanetary field turns southward with associated dayside reconnection on flux tubes with footpoints at lower latitudes. C1 Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Univ Maryland, Inst Phys Sci & Technol, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. ISSI, CH-3012 Bern, Switzerland. Univ Bergen, N-5007 Bergen, Norway. RP Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. EM nikost@ssl.berkeley.edu NR 48 TC 7 Z9 7 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9380 EI 2169-9402 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD MAR 21 PY 2003 VL 108 IS A4 AR 8013 DI 10.1029/2002JA009350 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 667JW UT WOS:000182229300001 ER PT J AU Srinivasan, R Daw, MS Noebe, RD Mills, MJ AF Srinivasan, R Daw, MS Noebe, RD Mills, MJ TI Observations of glide and decomposition of a(101) dislocations at high temperatures in Ni-Al single crystals deformed along the hard orientation SO PHILOSOPHICAL MAGAZINE LA English DT Article ID 1050 DEGREES K; INTERMEDIATE TEMPERATURES; PLASTIC-DEFORMATION; UNIFORM DEFORMATION; SLIP TRANSITION; VACANCY DEFECTS; SIMULATION; MECHANICS; BEHAVIOR; SYSTEMS AB Ni-44at.% Al and Ni-50 at.% Al single crystals were tested in compression in the hard <001> orientation. The dislocation processes and deformation behaviour were studied as a function of temperature, strain and strain rate. A slip transition in NiAl occurs from a<111> slip to non-a<111> slip at intermediate temperatures. In Ni-50 at. % Al single crystals, only a<010> dislocations are observed above the slip transition temperature. In contrast, a<101>{101} glide has been observed to control deformation beyond the slip transition temperature in, Ni-44 at.% Al. a<101> dislocations are observed primarily along both <111> directions in the glide plane. High-resolution transmission electron microscopy observations show that the core of the a<101> dislocations along these directions is decomposed into two a<010> dislocations, separated by, a distance of approximately 2nm. The temperature window of stability for these a<101> dislocations depends upon. the strain rate. At a strain rate of 1.4 x 10(-4) s(-1), a<101> dislocations are observed between 800 and 1000 K. Complete decomposition of a<101> dislocations into a<010> dislocations occurs beyond 1000 K, leading to a<010> climb as the deformation mode at higher temperatures. At lower strain rates, decomposition of a<101> dislocations has been observed to occur along the edge orientation at temperatures below 1000 K. Embedded-atom method calculations and experimental results indicate that a<101> dislocations have a large Peierls stress at low temperatures. Based on the present microstructural observations and a survey of the literature with respect to vacancy content and diffusion in NiAl, a model is proposed for a<101>{101} glide in Ni-44 at.% Al, and for the observed yield strength versus temperature behaviour of Ni-Al alloys at intermediate and high temperatures. C1 Ohio State Univ, Dept Mat Sci & Engn, Columbus, OH 43210 USA. Clemson Univ, Dept Phys & Astron, Clemson, SC 29634 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Srinivasan, R (reprint author), GE India Technol Ctr, Whitefield Rd, Bangalore 560066, Karnataka, India. EM srinivasan.r@geind.ge.com; daw@clemson.edu; ronald.d.noebe@grc.nasa.gov; mills.108@osu.edu NR 46 TC 6 Z9 6 U1 0 U2 3 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 1478-6443 J9 PHILOS MAG JI Philos. Mag. PD MAR 21 PY 2003 VL 83 IS 9 BP 1111 EP 1135 DI 10.1080/0141861021000047140 PG 25 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter SC Materials Science; Metallurgy & Metallurgical Engineering; Physics GA 660TR UT WOS:000181849900004 ER PT J AU Nussenzveig, HM AF Nussenzveig, HM TI Light tunneling in clouds SO APPLIED OPTICS LA English DT Article ID WATER CLOUDS; RADIATIVE PROPERTIES; ABSORPTION; EXTINCTION; RESONANCES; SCATTERING; PARTICLES; MICRODROPLETS; PERTURBATIONS; BACKSCATTER AB Solar radiation, traveling outside cloud water droplets, excites sharp resonances and surface waves by tunneling into the droplets. This effect contributes substantially to the total absorption (typically, of the order of 20%) and yields the major contribution to backscattering, producing the meteorological glory. Usual computational practices in atmospheric science misrepresent resonance contributions and cannot be relied on in the assessment of possible anomalies in cloud absorption. (C) 2003 Optical Society of America. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Fed Rio de Janeiro, Inst Fis, BR-21945970 Rio De Janeiro, Brazil. RP NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM moyses@if.ufrj.br NR 34 TC 13 Z9 13 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD MAR 20 PY 2003 VL 42 IS 9 BP 1588 EP 1593 DI 10.1364/AO.42.001588 PG 6 WC Optics SC Optics GA 658EJ UT WOS:000181708400005 PM 12665090 ER PT J AU Chiang, J Blaes, O AF Chiang, J Blaes, O TI Using multiwavelength observations to determine the black hole mass and accretion rate in the type 1 Seyfert galaxy NGC 5548 SO ASTROPHYSICAL JOURNAL LA English DT Article DE black hole physics; galaxies : active; galaxies : individual ( NGC 5548); galaxies : Seyfert; X-rays : galaxies ID ACTIVE GALACTIC NUCLEI; BROAD-LINE REGION; X-RAY; ULTRAVIOLET VARIABILITY; DISK MODELS; CYGNUS X-1; NGC-5548; CONTINUUM; EMISSION; SPECTRUM AB We model the spectral energy distribution of the type 1 Seyfert galaxy NGC 5548, fitting data from simultaneous optical, UV, and X-ray monitoring observations. We assume a geometry consisting of a hot central Comptonizing region surrounded by a thin accretion disk. The properties of the disk and the hot central region are determined by the feedback occurring between the hot Comptonizing region and thermal reprocessing in the disk that, along with viscous dissipation, provides the seed photons for the Comptonization process. The constraints imposed on this model by the multiwavelength data allow us to derive limits on the central black hole mass, Mless than or similar to2x10(7) M-circle dot, the accretion rate, Mless than or similar to2.5x10(5) M-circle dot(2) yr(-1)/M, and the radius of the transition region between the thin outer disk and the geometrically thick, hot inner region, similar to(2-5)x10(14) cm. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. RP Chiang, J (reprint author), Stanford Linear Accelerator Ctr, MS 43A,2575 Sand Hill Rd, Menlo Pk, CA 94025 USA. NR 40 TC 26 Z9 27 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 MAR 20 PY 2003 VL 586 IS 1 BP 97 EP 111 DI 10.1086/346260 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 653RV UT WOS:000181451600008 ER PT J AU Lee, CF Sahai, R AF Lee, CF Sahai, R TI Shaping proto-planetary and young planetary nebulae with collimated fast winds SO ASTROPHYSICAL JOURNAL LA English DT Article DE planetary nebulae : general; stars : AGB and post-AGB; stars : mass loss; stars : winds, outflows ID ASTROPHYSICALLY ABUNDANT ELEMENTS; RECOMBINATION RATE COEFFICIENTS; PHOTOIONIZATION CROSS-SECTIONS; LONG-SLIT SPECTROSCOPY; X-RAY-EMISSION; NUMERICAL SIMULATIONS; MASS-LOSS; CIRCUMSTELLAR ENVELOPES; RADIATION GASDYNAMICS; IONIZATION FRACTIONS AB Using two-dimensional hydrodynamical simulations, we investigate the interaction of a collimated fast wind (CFW) interacting with a spherical asymptotic giant branch (AGB) wind as the mechanism for shaping proto planetary nebulae (PPNs) and young planetary nebulae. In particular, we compare our simulations with the observations of an evolved PPN with multiple, highly collimated lobes, CRL 618. We characterize our model CFW by three parameters opening angle, velocity, and mass-loss rate and explore the dependence of the properties of the shell on the first two. For given opening angle and velocity, the mass-loss rate is chosen to give a shell velocity of about 150 km s(-1) at the tip, similar to that seen in CRL 618. In our simulations, the shell dynamics is found to depend on the velocity of the fast wind: we obtain a momentum-driven shell for a 300 km s(-1) fast wind and a ballistic bow shock driven shell for a 1000 km s(-1) fast wind. The shell driven by the collimated fast wind is highly collimated, even though the AGB wind is spherical. Time variations in the velocity of the fast wind produce a series of internal shock pairs interacting with the inner surface of the shell. As a result of radial expansion, the density of the internal shocks decreases with distance. Various emission diagnostics have been derived from our simulations. For a 300 km s(-1) fast wind, the optical emission arises from both the shocked AGB wind and shocked fast wind, showing one or two bright bowlike structures at the tip of the lobe. However, for a 1000 km s(-1) fast wind, since the shocked fast wind is much hotter, it emits mainly in X-ray emission; the optical emission forms only one bowlike structure at the tip associated with the shocked AGB wind. The position-velocity (PV) diagrams derived from our simulations all show a broad range of velocities at the tip. The detailed PV structure and velocity range at the tip depend on the shell dynamics and the relative contributions of the shocked fast wind and shocked AGB wind. We make a detailed comparison of our simulations to the observations of the relatively isolated northwestern (W1) lobe of CRL 618. We find that a 300 km s(-1) collimated fast wind with an opening angle of 10degrees can readily produce a highly collimated lobe similar to the W1 lobe, including the bowlike emission structure at its tip. However, our models have difficulty producing the bright emission structures seen along the body of the lobe. The [S II] lambda6716/lambda6730 ratios at the tip of the lobe in all of our simulations are similar to that observed at the tip of the W1 lobe. The optical line ratios indicate a temperature strati cation in the tip; for both the simulations and observations, however, the temperatures at the tip of the lobe in our simulations are higher than observed. The position-velocity (PV) diagrams derived from our simulations are all qualitatively consistent with the current observations. The collimated fast wind in CRL 618 is unlikely to be steady and is not radiatively driven. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lee, CF (reprint author), CALTECH, Jet Prop Lab, Mail Stop 183-900,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM chinfei@eclipse.jpl.nasa.gov; sahai@eclipse.jpl.nasa.gov NR 71 TC 65 Z9 65 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 MAR 20 PY 2003 VL 586 IS 1 BP 319 EP 337 DI 10.1086/346265 PN 1 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 653RV UT WOS:000181451600026 ER PT J AU Christodoulou, DM Contopoulos, J Kazanas, D AF Christodoulou, DM Contopoulos, J Kazanas, D TI Interchange method in compressible magnetized couette flow: Magnetorotational and magnetoconvective instabilities SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; hydrodynamics; instabilities; MHD; stars : magnetic fields; stars : mass loss ID PHASE-TRANSITION THEORY; ACCRETION DISKS; 3 DIMENSIONS; BLACK-HOLES; PLASMA; FLUX; CONVECTION; STABILITY; TRANSPORT AB We obtain the general forms of the axisymmetric stability criteria in a magnetized compressible Couette flow using an energy variational principle, the so-called interchange or Chandrasekhar's method, which we applied successfully in the incompressible case. This formulation accounts for the simultaneous presence of gravity, rotation, a toroidal magnetic field, a weak axial magnetic field, entropy gradients, and density gradients in the initial equilibrium state. The power of the method lies in its simplicity, which allows us to derive extremely compact and physically clear expressions for the relevant stability criteria despite the inclusion of so many physical effects. In the implementation of the method, all the applicable conservation laws are explicitly taken into account during the variations of a quantity with dimensions of energy that we call the free-energy function. As in the incompressible case, the presence of an axial field invalidates the conservation laws of angular momentum and azimuthal magnetic flux and introduces instead isorotation and axial current conservation along field lines. Our results are therefore markedly different depending on whether an axial magnetic field is present, and they generalize in two simple expressions all previously known, partial stability criteria for the appearance of magnetorotational instability. Furthermore, the coupling between magnetic tension and buoyancy and its influence to the dynamics of nonhomoentropic magnetized flows become quite clear from our results. In the limits of plane-parallel atmospheres and homoentropic flows, our formulation easily recovers the stability criteria for suppression of convective and Parker instabilities, as well as some related special cases studied over 40 years ago by Newcomb and Tserkovnikov via laborious variational techniques. C1 Lucent Technol, Westford, MA 01886 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Christodoulou, DM (reprint author), Lucent Technol, 1 Robbins Rd, Westford, MA 01886 USA. NR 47 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 MAR 20 PY 2003 VL 586 IS 1 BP 372 EP 383 DI 10.1086/367615 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 653RV UT WOS:000181451600030 ER PT J AU Smith, N Davidson, K Gull, TR Ishibashi, K Hillier, DJ AF Smith, N Davidson, K Gull, TR Ishibashi, K Hillier, DJ TI Latitude-dependent effects in the stellar wind of eta Carinae SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; stars : individual (eta Carinae); stars : mass loss; stars : winds, outflows ID HUBBLE-SPACE-TELESCOPE; RADIATION-DRIVEN WINDS; LUMINOUS BLUE VARIABLES; ROTATING B-STARS; HOMUNCULUS-NEBULA; MASS-LOSS; IMAGING SPECTROGRAPH; BINARY HYPOTHESIS; EQUATORIAL EJECTA; DISK FORMATION AB The Homunculus reflection nebula around eta Carinae provides a rare opportunity to observe the spectrum of a star from more than one direction. In the case of eta Car, the nebula's geometry is known well enough to infer how line profiles vary with latitude. We present Space Telescope Imaging Spectrograph ( STIS) spectra of several positions in the Homunculus, showing directly that eta Car has an aspherical stellar wind. P Cygni absorption in Balmer lines depends on latitude, with relatively high velocities and strong absorption near the polar axis. Stronger absorption at high latitudes is surprising, and it suggests higher mass flux toward the poles, perhaps resulting from radiative driving with equatorial gravity darkening on a rotating star. Reflected profiles of He I lines are more puzzling, offering clues to the wind geometry and ionization structure. During eta Car's high-excitation state in 2000 March, the wind was fast and dense at the poles, with higher ionization at low latitudes. Older STIS data obtained since 1998 reveal that this global stellar wind geometry changes during eta Car's 5.5 yr cycle and may suggest that this star's spectroscopic events are shell ejections. Whether or not a companion star triggers these outbursts remains ambiguous. The most dramatic changes in the wind occur at low latitudes, while the dense polar wind remains relatively undisturbed during an event. The apparent stability of the polar wind also supports the inferred bipolar geometry. The wind geometry and its variability have critical implications for understanding the 5.5 yr cycle and long-term variability but do not provide a clear alternative to the binary hypothesis for generating eta Car's X-rays. C1 Univ Minnesota, Dept Astron, Minneapolis, MN 55455 USA. NASA, Goddard Space Flight Ctr, Lab Astron & Solar Sci, Greenbelt, MD 20771 USA. MIT, Ctr Space Res, Cambridge, MA 02139 USA. Univ Pittsburgh, Dept Phys & Astron, Pittsburgh, PA 15260 USA. RP Smith, N (reprint author), Univ Colorado, Ctr Astrophys & Space Astron, 389 UCB, Boulder, CO 80309 USA. RI Gull, Theodore/D-2753-2012 OI Gull, Theodore/0000-0002-6851-5380 NR 94 TC 138 Z9 138 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 MAR 20 PY 2003 VL 586 IS 1 BP 432 EP 450 DI 10.1086/367641 PN 1 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 653RV UT WOS:000181451600036 ER PT J AU Burgasser, AJ Kirkpatrick, JD Reid, IN Brown, ME Miskey, CL Gizis, JE AF Burgasser, AJ Kirkpatrick, JD Reid, IN Brown, ME Miskey, CL Gizis, JE TI Binarity in brown dwarfs: T dwarf binaries discovered with the Hubble Space Telescope Wide Field Planetary Camera 2 SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : visual; stars : formation; stars : fundamental parameters; stars : individual (2MASS J12171110-011131, 2MASS J12255432-2739466,2MASS J15344984-2952274); stars : low-mass, brown dwarfs ID DIGITAL SKY SURVEY; LOW-MASS BINARIES; SOLAR-TYPE STARS; SURVEY COMMISSIONING DATA; EXTRASOLAR GIANT PLANETS; H-ALPHA EMISSION; CLUSTER IC 348; GLIESE 229B; SPECTRAL CLASSIFICATION; LUMINOSITY FUNCTION AB We present the discovery of two T dwarf binaries, 2MASS 1225 2739AB and 2MASS 1534-2952AB, identified in a sample of 10 T dwarfs imaged with the Hubble Space Telescope (HST) Wide Field Planetary Camera 2. Companionship is established by the uniquely red F814W-F1042M colors of the binary components, caused by heavily pressure-broadened K I absorption centered at 7665 and 7699 Angstrom. The separations of the two binary systems are 0."282 +/- 0."005 and 0."065 +/- 0."007, implying projected separations of 3.17 +/- 0.14 and 1.0 +/- 0.3 AU, respectively. These close separations are similar to those found in previous brown dwarf binary searches and permit orbital mapping over the coming decade. 2MASS 1225 2739AB has a substantially fainter secondary, with DeltaM(F814W) = 1.59 +/- 0.04 and DeltaM(F1042M) = 1.05 +/- 0.03; this system is likely composed of a T6 primary and T8 secondary with mass ratio 0.7-0.8. The observed binary fraction of our HST sample, 20(-7)(+17) %, is consistent with results obtained for late-type M and L field dwarfs and implies a bias-corrected binary fraction of 9(-4)(+15)% for a greater than or similar to1 AU and qgreater than or similar to0.4, significantly lower than the binary fractions of F-G and early-type M dwarf stars. Neither of the T binaries have separations agreater than or similar to10 AU, consistent with results from other brown dwarf binary searches. Using the statistical models of Weinberg, Shapiro, & Wasserman, we conclude that tidal disruption by passing stars or giant molecular clouds, which limits the extent of wide stellar binaries, plays no role in eliminating wide brown dwarf binaries, implying either disruption very early in the formation process (ages less than or similar to1-10 Myr) or a formation mechanism that precludes such systems. We find that the maximum binary separation in the brown dwarf regime appears to scale as M(total)(2), a possible clue to the physical mechanism that restricts wide substellar systems. C1 Univ Calif Los Angeles, Div Astron & Astrophys, Los Angeles, CA 90095 USA. CALTECH, Ctr Infrared Proc & Anal, Pasadena, CA 91125 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. Catholic Univ Amer, Dept Phys, Inst Astrophys & Computat Sci, Washington, DC 20064 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Delaware, Dept Phys & Astron, Newark, DE 19716 USA. RP Burgasser, AJ (reprint author), Univ Calif Los Angeles, Div Astron & Astrophys, Los Angeles, CA 90095 USA. EM adam@astro.ucla.edu; davy@ipac.caltech.edu; inr@stsci.edu; mbrown@gps.caltech.edu; miskey@iacs.gsfc.nasa.gov; gizis@udel.edu NR 85 TC 265 Z9 265 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 MAR 20 PY 2003 VL 586 IS 1 BP 512 EP 526 DI 10.1086/346263 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 653RV UT WOS:000181451600042 ER PT J AU Gopalswamy, N Shimojo, M Lu, W Yashiro, S Shibasaki, K Howard, RA AF Gopalswamy, N Shimojo, M Lu, W Yashiro, S Shibasaki, K Howard, RA TI Prominence eruptions and coronal mass ejection: A statistical study using microwave observations SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : corona; Sun : coronal mass ejections (CMEs) Sun : filaments; Sun : prominences; Sun : radio radiation ID H-ALPHA; X-RAY; RADIO; MISSION; ANGLE; SOHO AB We present the results of a statistical study of a large number of solar prominence events (PEs) observed by the Nobeyama Radioheliograph. We studied the association rate, relative timing, and spatial correspondence between PEs and coronal mass ejections (CMEs). We classified the PEs as radial and transverse, depending on whether the prominence moved predominantly in the radial or horizontal direction. The radial events were faster and attained a larger height above the solar surface than the transverse events. Out of the 186 events studied, 152 (82%) were radial events, while only 34 (18%) were transverse events. Comparison with white-light CME data revealed that 134 (72%) PEs were clearly associated with CMEs. We compare our results with those of other studies involving PEs and white-light CMEs in order to address the controversy in the rate of association between CMEs and prominence eruptions. We also studied the temporal and spatial relationship between prominence and CME events. The CMEs and PEs seem to start roughly at the same time. There was no solar cycle dependence of the temporal relationship. The spatial relationship was, however, solar cycle dependent. During the solar minimum, the central position angle of the CMEs had a tendency to be offset closer to the equator as compared to that of the PE, while no such effect was seen during solar maximum. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. Nobeyama Radio Observ, Minamisa Ku, Nagano 3841305, Japan. Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. USN, Res Lab, Div Space Sci, Washington, DC 20375 USA. RP Gopalswamy, N (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. RI Gopalswamy, Nat/D-3659-2012; Shimojo, Masumi/J-2605-2016; OI Shimojo, Masumi/0000-0002-2350-3749; Gopalswamy, Nat/0000-0001-5894-9954 NR 29 TC 160 Z9 165 U1 1 U2 5 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 20 PY 2003 VL 586 IS 1 BP 562 EP 578 DI 10.1086/367614 PN 1 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 653RV UT WOS:000181451600045 ER PT J AU Holman, GD AF Holman, GD TI The effects of low- and high-energy cutoffs on solar flare microwave and hard X-ray spectra SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : flares; Sun : radio radiation; Sun : X-rays, gamma rays ID THERMAL NONTHERMAL MODEL; CONTINUUM EMISSION; BURSTS; ELECTRONS; ARRAY AB Microwave and hard X-ray spectra provide crucial information about energetic electrons and their environment in solar flares. Both microwave and hard X-ray spectra are sensitive to cutoffs in the electron distribution function. The determination of the high-energy cutoff from these spectra establishes the highest electron energies produced by the acceleration mechanism, while determination of the low-energy cutoff is crucial to establishing the total energy in accelerated electrons. I present computations of the effects of both high- and low-energy cutoffs on microwave and hard X-ray spectra. The optically thick portion of a microwave spectrum is enhanced and smoothed by a low-energy cutoff, while a hard X-ray spectrum is flattened below the cutoff energy. A high- energy cutoff steepens the microwave spectrum and increases the wavelength at which the spectrum peaks, while the hard X-ray spectrum begins to steepen at photon energies an order of magnitude or more below the electron cutoff energy. I discuss how are microwave and hard X-ray spectra can be analyzed together to determine these electron cutoff energies. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Holman, GD (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Holman, Gordon/C-9548-2012 NR 25 TC 63 Z9 65 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 MAR 20 PY 2003 VL 586 IS 1 BP 606 EP 616 DI 10.1086/367554 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 653RV UT WOS:000181451600048 ER PT J AU Angelini, L White, NE AF Angelini, L White, NE TI An XMM-Newton observation of 4U 1755-33 in quiescence: Evidence of a fossil X-ray jet SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : close; stars : individual (4U 1755-33, V4134 Sagittarii); X-rays : stars ID BLACK-HOLE; SPECTRUM; X1755-338; TRANSIENTS; EMISSION; CHANDRA; SS-433 AB We report an XMM-Newton observation of the low-mass X-ray binary and black hole candidate 4U 1755-33. This source had been a bright persistent source for at least 25 yr, but in 1995 it entered an extended quiescent phase. 4U 1755-33 was not detected with an upper limit to the 2-10 keV luminosity of 3.6 x 10(31) d(4kpc)(2) ergs s(-1) (where d(4 kpc) is the distance in units of 4 kpc)-consistent with the luminosity of other black hole candidates in a quiescent state. An unexpected result is the discovery of a narrow 7' long X-ray jetlike feature centered on the position of 4U 1755-33. The spectrum of the jet is similar to that observed from other galactic and extragalactic jets thought to be associated with accreting black holes. The detection of a fossil jet provides additional evidence supporting the black hole candidacy of 4U 1755-33. The spectral properties of three bright serendipitous sources in the field are reported, and it is suggested that these are background active galactic nuclei. C1 NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Code 660, Greenbelt, MD 20771 USA. EM angelini@davide.gsfc.nasa.gov; nwhite@lheapop.gsfc.nasa.gov RI White, Nicholas/B-6428-2012 OI White, Nicholas/0000-0003-3853-3462 NR 24 TC 30 Z9 30 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 MAR 20 PY 2003 VL 586 IS 1 BP L71 EP L75 DI 10.1086/374682 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 653RX UT WOS:000181451800017 ER PT J AU Hudson, RL Moore, MH AF Hudson, RL Moore, MH TI Solid-phase formation of interstellar vinyl alcohol SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : molecules; line : formation; line : identification; molecular processes ID INFRARED-SPECTROSCOPY; ICE ANALOGS; ACETALDEHYDE; TEMPERATURE; PHOTOLYSIS; CHEMISTRY; RELEVANT; CH2=CHOH; SPECTRUM; OXYGEN AB Motivated by the recent discovery of gas-phase interstellar vinyl alcohol, CH(2)=CH(OH), we present laboratory experiments on this molecule's solid-phase formation. Through a combination of reaction chemistry, infrared spectroscopy, isotopic substitution, thermal annealings, and independent syntheses, we have identified vinyl alcohol in proton-irradiated H(2)O + C(2)H(2) ices and have measured its column density at similar to15 K. UV photolysis of H(2)O + C(2)H(2) ices at similar to15 K also produces vinyl alcohol. It is suggested that vinyl alcohol is formed in interstellar ices and then ejected into the gas phase, where it might undergo additional reactions. C1 Eckerd Coll, Dept Chem, St Petersburg, FL 33733 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Hudson, RL (reprint author), Eckerd Coll, Dept Chem, 4200 54th Ave S, St Petersburg, FL 33733 USA. EM hudsonrl@eckerd.edu; ummhm@lepvax.gsfc.nasa.gov RI Hudson, Reggie/E-2335-2012 NR 29 TC 15 Z9 15 U1 3 U2 6 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 20 PY 2003 VL 586 IS 1 BP L107 EP L110 DI 10.1086/374580 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 653RX UT WOS:000181451800025 ER PT J AU Mukai, K Kinkhabwala, A Peterson, JR Kahn, SM Paerels, F AF Mukai, K Kinkhabwala, A Peterson, JR Kahn, SM Paerels, F TI Two types of X-ray spectra in cataclysmic variables SO ASTROPHYSICAL JOURNAL LA English DT Article DE novae, cataclysmic variables; X-rays : binaries ID REFLECTION GRATING SPECTROMETER; WHITE-DWARF; GINGA DATA; EMISSION; CHANDRA; ACCRETION; NGC-1068 AB We present Chandra high-energy transmission grating spectra of seven cataclysmic variables. We find that they divide unambiguously into two distinct types. Spectra of the first type are remarkably well fitted by a simple cooling flow model, which assumes only steady-state isobaric radiative cooling. The maximum temperature, kT(max), and the normalization, which provides a highly precise measurement of the accretion rate, are the only free parameters of this model. Spectra of the second type are grossly inconsistent with a cooling flow model. They instead exhibit a hard continuum and show strong H-like and He-like ion emission but little Fe L-shell emission, which is consistent with expectations for line emission from a photoionized plasma. Using a simple photoionization model, we argue that the observed line emission for these sources can be driven entirely by the hard continuum. The physical significance of these two distinct types of X-ray spectra is also explored. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Columbia Univ, Columbia Astrophys Lab, New York, NY 10027 USA. RP Mukai, K (reprint author), NASA, Goddard Space Flight Ctr, Code 662, Greenbelt, MD 20771 USA. NR 27 TC 80 Z9 80 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 MAR 20 PY 2003 VL 586 IS 1 BP L77 EP L80 DI 10.1086/374583 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 653RX UT WOS:000181451800018 ER PT J AU Rea, N Israel, GL Stella, L Oosterbroek, T Mereghetti, S Angelini, L Campana, S Covino, S AF Rea, N Israel, GL Stella, L Oosterbroek, T Mereghetti, S Angelini, L Campana, S Covino, S TI Evidence of a cyclotron feature in the spectrum of the anomalous X-ray pulsar 1RXS J170849-400910 SO ASTROPHYSICAL JOURNAL LA English DT Article DE pulsars : general; pulsars : individual (1RXS J170849-400910); stars : magnetic fields; X-rays : stars ID MAGNETIZED NEUTRON-STARS; ABSORPTION FEATURE; ACCRETION; REPEATERS; EMISSION; BEPPOSAX AB We report the results of a long observation of the anomalous X-ray pulsar 1RXS J170849-400910 obtained with the BeppoSAX satellite in 2001 August. The best-fit phase-averaged spectrum was an absorbed power-law plus blackbody model, with a photon index of Gamma similar to 2.4 and a blackbody temperature of kT(bb) similar to 0.4 keV. We confirm the presence of significant spectral variations with the rotational phase of the pulsar. In the spectrum corresponding to the rising part of the pulse, we found an absorption-like feature at similar to8.1 keV (a significance of 4 sigma), most likely due to cyclotron resonant scattering. The centroid energy converts to a magnetic field of and 9 x 10(11) and 1.6 x 10(15) G in the case of electrons and protons, respectively. If confirmed, this would be the first detection of a cyclotron feature in the spectrum of an anomalous X-ray pulsar. C1 Univ Roma Tor Vergata, I-00133 Rome, Italy. Osserv Astron Roma, INAF, I-00040 Monte Porzio Catone, Italy. European Space Agcy, ESTEC, Astrophys Missions Div, Res & Sci Support Dept, NL-2200 AG Noordwijk, Netherlands. CNR, Ist Fis Cosm G Occhialini, I-20133 Milan, Italy. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Osserv Astron Brera, INAF, I-23807 Merate, LC, Italy. RP Rea, N (reprint author), Univ Roma Tor Vergata, Via Ricerca Sci 1, I-00133 Rome, Italy. RI Rea, Nanda/I-2853-2015; OI Rea, Nanda/0000-0003-2177-6388; Campana, Sergio/0000-0001-6278-1576; MEREGHETTI, SANDRO/0000-0003-3259-7801; Israel, GianLuca/0000-0001-5480-6438; Covino, Stefano/0000-0001-9078-5507 NR 36 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 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 20 PY 2003 VL 586 IS 1 BP L65 EP L69 DI 10.1086/374585 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 653RX UT WOS:000181451800016 ER PT J AU Reames, DV McDonald, FB AF Reames, DV McDonald, FB TI Wind observations of anomalous cosmic rays from solar minimum to maximum SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic rays; interplanetary medium; solar wind; Sun : magnetic fields ID ENERGETIC PARTICLES; OUTER HELIOSPHERE; MODULATION; SPECTRA; ACCELERATION; SPACECRAFT; COMPONENT; NITROGEN; OXYGEN; SHOCK AB We report the first observation near Earth of the time behavior of anomalous cosmic-ray N, O, and Ne ions through the period surrounding the maximum of the solar cycle. These observations were made by the Wind spacecraft during the 1995-2002 period spanning times from solar minimum through solar maximum. Comparison of anomalous and Galactic cosmic rays provides a powerful tool for the study of the physics of solar modulation throughout the solar cycle. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland, Inst Phys Sci & Technol, College Pk, MD 20742 USA. RP Reames, DV (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. NR 19 TC 8 Z9 8 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 20 PY 2003 VL 586 IS 1 BP L99 EP L101 DI 10.1086/374653 PN 2 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 653RX UT WOS:000181451800023 ER PT J AU Sahai, R Zijlstra, A Contreras, CS Morris, M AF Sahai, R Zijlstra, A Contreras, CS Morris, M TI An icy, bipolar proto-planetary nebula with Knotty jets: IRAS 22036-5306 SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; planetary nebulae : general; reflection nebulae; stars : AGB and post-AGB; stars : individual (IRAS 22036+5306); stars : mass loss ID PROTOPLANETARY NEBULA; OH/IR STARS; MASS-LOSS; DISCOVERY; ENVELOPES; AGB; OUTFLOW AB Using the Hubble Space Telescope's Wide Field Planetary Camera 2, we have discovered that the proto-planetary nebula (PPN) IRAS 22036+5306 (I22036) is an extended (5."7 x 1."3) bipolar nebula. A dark, (partial) ringlike band defines the nebular waist region and probably results from a tilted, geometrically thick disk that obscures the central star. Knotty, linear structures are seen in each lobe. Very Large Array A configuration observations of OH maser emission in I22036 show the 1667 MHz emission features aligned in a roughly 1."8 long linear structure along the nebular axis. The source's far-infrared fluxes imply the presence of a massive [similar to5(D/2 kpc)(2) M-.], dusty, cool (T-dust similar to 35-67 K), circumstellar envelope. Strong 3.08 and 11 mum absorption features in the Infrared Space Observatory spectra show the presence of icy silicate grains, which probably reside in the disk's shielded outer regions. A low-resolution optical spectrum indicates an F5 (or earlier) spectral type for the post-asymptotic giant branch (AGB) central star and shows Halpha and Hbeta emission lines. The elongated and highly structured lobes of I22036 are likely to have been produced as a result of the interaction of a collimated, fast wind (CFW) with the AGB progenitor's dense, slow wind. Highly collimated jetlike components in the CFW have probably operated at some time during the formation of this PPN. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Manchester, Inst Sci & Technol, Dept Phys, Manchester M60 1QD, Lancs, England. CALTECH, Dept Astron, Pasadena, CA 91125 USA. Univ Calif Los Angeles, Div Astron & Astrophys, Los Angeles, CA 90095 USA. RP Sahai, R (reprint author), CALTECH, Jet Prop Lab, MS 183-900,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 34 TC 22 Z9 22 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 20 PY 2003 VL 586 IS 1 BP L81 EP L85 DI 10.1086/374582 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 653RX UT WOS:000181451800019 ER PT J AU Sambruna, RM Gliozzi, M Eracleous, M Brandt, WN Mushotzky, R AF Sambruna, RM Gliozzi, M Eracleous, M Brandt, WN Mushotzky, R TI The XMM-Newton view of the nucleus of NGC 4261 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : elliptical and lenticular, cD; galaxies : individual (NGC 4261, 3C 270); galaxies : jets; X-rays : galaxies ID ACTIVE GALACTIC NUCLEI; LINE RADIO GALAXIES; X-RAY-SPECTRA; BLACK-HOLES; EMISSION; ACCRETION; NGC-4261; ASCA; JET AB We present the first results from an XMM-Newton observation of the Fanaroff-Riley type I galaxy NGC 4261, which harbors a supermassive black hole and a low-ionization nuclear emission-line region. Here we focus on the X-ray properties of the nucleus, using the European Photon Imaging Camera pn data. The 0.6-10 keV continuum in best fitted by a thermal component with kT similar to 0.7 keV, plus a power law with photon index Gamma similar to 1.4, absorbed by a column density N-H similar to 4 x 10(22) cm(-2). An unresolved Fe K emission line with EW similar to 280 eV is detected at similar to7 keV. We also detect, for the first time, short-term flux variability from the nucleus, on a timescale of 3-5 ks. The short-term variations rule out an advection-dominated accretion flow as the only production mechanism of the X-ray continuum. Instead, we argue that the inner jet contributes to the emission in the X-ray band. C1 George Mason Univ, Dept Phys & Astron, Fairfax, VA 22030 USA. Penn State Univ, Dept Astron & Astrophys, Davy Lab 525, University Pk, PA 16802 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Sambruna, RM (reprint author), George Mason Univ, Dept Phys & Astron, 4400 Univ Dr,MS 3F3, Fairfax, VA 22030 USA. RI Brandt, William/N-2844-2015 OI Brandt, William/0000-0002-0167-2453 NR 27 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 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 20 PY 2003 VL 586 IS 1 BP L37 EP L40 DI 10.1086/374612 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 653RX UT WOS:000181451800009 ER PT J AU Strohmayer, TE Mushotzky, RF AF Strohmayer, TE Mushotzky, RF TI Discovery of X-ray quasi-periodic oscillations from an ultraluminous X-ray source in M82: Evidence against beaming SO ASTROPHYSICAL JOURNAL LA English DT Article DE black hole physics; galaxies : individual (M82); galaxies : starburst; stars : oscillations; X-rays : galaxies; X-rays : stars ID ACCRETION DISKS; BLACK-HOLES; RXTE OBSERVATIONS; GALAXIES; CHANDRA AB We report the discovery with the European Photon Imaging Camera CCDs on board XMM-Newton of a 54 mHz quasi-periodic oscillation (QPO) in the greater than 2 keV X-ray flux from an ultraluminous X-ray source (ULX) in the starburst galaxy M82. This is the first detection of a QPO in the X-ray flux from an extragalactic ULX and confirms that the source is a compact object. On the basis of the QPO strength and previous Chandra observations, it appears likely that the QPO is associated with the most luminous object in the central region of M82, CXO M82 J095550.2+694047; however, XMM imaging alone is not sufficient to unambiguously confirm this. The other plausible candidate is CXO M82 J095551.1+694045; however, the QPO luminosity is comparable to the peak luminosity of this object in Chandra observations, which argues against it being the source of the QPO. The QPO had a centroid frequency of 54.3 +/- 0.9 mHz, a coherence Q = nu(o)/Deltanu(fwhm) approximate to5, and an amplitude (rms) in the 2-10 keV band of 8.5%. Below 0.2 Hz, the power spectrum can be fitted by a power law with index approximate to1 and amplitude (rms) of 13.5%. The X-ray spectrum requires a curving continuum, with a disk blackbody at T = 3.1 keV providing an acceptable fit. A broad Fe line centered at 6.55 keV is required in all fits, but the equivalent width is sensitive to the continuum model. There is no evidence of a reflection component. The implied bolometric luminosity is approximate to(4-5) x 10(40) ergs s(-1). Archival Rossi X-Ray Timing Explorer pointings at M82 also show evidence for QPOs in the 50-100 mHz frequency range. We discuss the implications of our findings for models of ULXs. C1 NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Strohmayer, TE (reprint author), NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Code 660, Greenbelt, MD 20771 USA. NR 24 TC 176 Z9 177 U1 2 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 20 PY 2003 VL 586 IS 1 BP L61 EP L64 DI 10.1086/374732 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 653RX UT WOS:000181451800015 ER PT J AU Ponchak, GE Schwartz, ZD Alterovitz, SA Downey, AN Freeman, JC AF Ponchak, GE Schwartz, ZD Alterovitz, SA Downey, AN Freeman, JC TI Temperature dependence of attenuation of coplanar waveguide on semi-insulating 4H-SiC through 540 degrees C SO ELECTRONICS LETTERS LA English DT Article AB For the first time, the temperature and frequency dependence of the attenuation of a coplanar waveguide on semi-insulating 4H-SiC substrate is reported. At 500degreesC the attenuation increases by 2 dB/cm at 1 GHz and by 3.25 dB/cm at 50 GHz. This appears to be mainly due to a decrease in the SiC resistivity as the temperature increases. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NASA, Glenn Res Ctr, Analex Corp, Cleveland, OH 44135 USA. RP Ponchak, GE (reprint author), NASA, Glenn Res Ctr, 2100 Brookpk Rd,MS 54-5, Cleveland, OH 44135 USA. NR 2 TC 7 Z9 7 U1 0 U2 1 PU IEE-INST ELEC ENG PI HERTFORD PA MICHAEL FARADAY HOUSE SIX HILLS WAY STEVENAGE, HERTFORD SG1 2AY, ENGLAND SN 0013-5194 J9 ELECTRON LETT JI Electron. Lett. PD MAR 20 PY 2003 VL 39 IS 6 BP 535 EP 536 DI 10.1049/el:20030356 PG 2 WC Engineering, Electrical & Electronic SC Engineering GA 662HJ UT WOS:000181941000033 ER PT J AU Cohen, SC Darby, DJ AF Cohen, SC Darby, DJ TI Tectonic plate coupling and elastic thickness derived from the inversion of a steady state viscoelastic model using geodetic data: Application to southern North Island, New Zealand SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article DE lithospheric thickness; New Zealand; viscoelastic model inversion; crustal deformation ID SUBDUCTION ZONE; HIKURANGI PLATEAU; DISLOCATION MODEL; 1992 LANDERS; EARTHQUAKE; STRAIN; THRUST; MANTLE; JAPAN AB [1] A steady state viscoelastic model of deformation at an oblique convergence zone is used to analyze crustal velocities deduced from Global Positioning System (GPS) observations in southern North Island, New Zealand. The model is physically more reasonable than elastic dislocation theory because the tectonic plates have finite elastic thicknesses. In an inversion that makes use of Green's functions derived from finite element calculations, we solve for depth-dependent fault backslip rates. The associated chi-squared goodness of fit parameter depends on the values of the elastic thicknesses of the overriding Australian and subducting Pacific Plates. These thicknesses are systematically varied in order to find the chi-squared minimum. We find that: (1) the plates have coupling coefficient between 0.8 and 1.0 to a depth of about 22 km; (2) elastic dislocation theory appears to adequately fit the observations because the effects of viscoelastic flow are small; (3) viscoelastic results depend on the contrast between the elastic moduli of the plates, (4) the trench normal, rather than the trench parallel component of motion is more diagnostic for choosing between models with different parameters; (5) for the favored model (one with a weak continental crust), the estimated value of the Pacific Plate thickness is 40-60 km. Although the estimates of the plate thickness are not tightly constrained, those deduced from geodetic data tend to be larger than those deduced from geologic data, consistent with the idea that thickness estimates depend on the time scale of the loading process. C1 NASA, Geodynam Branch, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Gracefield Res Ctr, Inst Geol & Nucl Sci, Lower Hutt, New Zealand. RP Cohen, SC (reprint author), NASA, Geodynam Branch, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM Steven.C.Cohen@nasa.gov NR 38 TC 4 Z9 4 U1 0 U2 0 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 MAR 20 PY 2003 VL 108 IS B3 AR 2164 DI 10.1029/2001JB001687 PG 14 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 667JH UT WOS:000182228000003 ER PT J AU Fox, DW Yost, S Kulkarni, SR Torii, K Kato, T Yamaoka, H Sako, M Harrison, FA Sari, R Price, PA Berger, E Soderberg, AM Djorgovski, SG Barth, AJ Pravdo, SH Frail, DA Gal-Yam, A Lipkin, Y Mauch, T Harrison, C Buttery, H AF Fox, DW Yost, S Kulkarni, SR Torii, K Kato, T Yamaoka, H Sako, M Harrison, FA Sari, R Price, PA Berger, E Soderberg, AM Djorgovski, SG Barth, AJ Pravdo, SH Frail, DA Gal-Yam, A Lipkin, Y Mauch, T Harrison, C Buttery, H TI Early optical emission from the gamma-ray burst of 4 October 2002 SO NATURE LA English DT Article ID AFTERGLOWS; SEARCH AB Observations of the long-lived emission-or 'afterglow'-of long-duration gamma-ray bursts place them at cosmological distances, but the origin of these energetic explosions remains a mystery. Observations of optical emission contemporaneous with the burst of gamma-rays should provide insight into the details of the explosion, as well as into the structure of the surrounding environment. One bright optical flash was detected during a burst(1) but other efforts(2,3) have produced negative results. Here we report the discovery of the optical counterpart of GRB021004 only 193 seconds after the event. The initial decline is unexpectedly slow and requires varying energy content in the gamma-ray burst blastwave over the course of the first hour. Further analysis of the X-ray and optical afterglow suggests additional energy variations over the first few days. C1 CALTECH, CALTECH Opt Observ 105 24, Pasadena, CA 91125 USA. CALTECH, Space Radiat Lab 220 47, Pasadena, CA 91125 USA. CALTECH, Theoret Astrophys 130 33, Pasadena, CA 91125 USA. RIKEN, Cosmic Radiat Lab, Wako, Saitama 3510198, Japan. Kyoto Univ, Dept Astron, Sakyo Ku, Kyoto 6068502, Japan. Kyushu Univ, Dept Phys, Chuo Ku, Fukuoka 8108560, Japan. Mt Stromlo & Siding Spring Observ, RSAA, Weston, ACT 2611, Australia. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Natl Radio Astron Observ, Socorro, NM 87801 USA. Tel Aviv Univ, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. Univ Sydney, Sch Phys, Sydney, NSW 2006, Australia. Univ Cambridge, Cavendish Lab, Astrophys Grp, Cambridge CB3 0HE, England. RP Fox, DW (reprint author), CALTECH, CALTECH Opt Observ 105 24, Pasadena, CA 91125 USA. NR 28 TC 103 Z9 104 U1 0 U2 3 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD MAR 20 PY 2003 VL 422 IS 6929 BP 284 EP 286 DI 10.1038/nature01504 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 656XX UT WOS:000181637300032 PM 12646914 ER PT J AU Grousset, FE Ginoux, P Bory, A Biscaye, PE AF Grousset, FE Ginoux, P Bory, A Biscaye, PE TI Case study of a Chinese dust plume reaching the French Alps SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID AIR-POLLUTION; MINERAL DUST; DEPOSITION; ATLANTIC; TRANSPORT; GREENLAND; AEROSOLS; REGIONS; PACIFIC; MODEL AB [1] By combining reconstruction of airmass back-trajectories from dust deposition sites in Europe and measurements of the (Nd) isotopic composition of deposited dust particles, potential sources of different Saharan dust events can be identified. The study of "red dust'' events collected in France allowed us to identify distinct North African source areas (e.g. Lybia vs. Mauritania). Surprisingly, the airmass trajectory of one dust event (March 6, 1990) was distinct from the others, and revealed a Chinese origin. The Nd isotopic composition of this dust was consistent with the range of isotopic compositions of Chinese loess. Moreover, an atmospheric global model simulation reveals that a dust plume left China before February 25, 1990, flew over North America around the February/March transition and reached the French Alps by March 6, 1990, revealing that intercontinental dust and pollutant transport may occur across the Pacific Ocean and the North Atlantic at the Westerlies latitudes. C1 Univ Maryland Baltimore Cty, GEST, NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Bordeaux 1, CNRS, UMR 5805, EPOC, F-33405 Talence, France. Columbia Univ, Lamont Doherty Geol Observ, Palisades, NY 10964 USA. British Antarctic Survey, Cambridge CB3 0ET, England. RP Grousset, FE (reprint author), Univ Maryland Baltimore Cty, GEST, NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Ginoux, Paul/C-2326-2008 OI Ginoux, Paul/0000-0003-3642-2988 NR 26 TC 90 Z9 95 U1 4 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 MAR 19 PY 2003 VL 30 IS 6 AR 1277 DI 10.1029/2002GL016833 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 667FA UT WOS:000182219500008 ER PT J AU Yazdanbakhsh, AP Vrtovec, B Radovancevic, B Schlegel, TT AF Yazdanbakhsh, AP Vrtovec, B Radovancevic, B Schlegel, TT TI Increased levels of high-sensitivity C-reactive protein are associated with a longer QTc interval in apparently healthy subjects SO JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY LA English DT Meeting Abstract CT 52nd Annual Scientific Session of the American-College-of-Cardiology CY MAR 30-APR 02, 2003 CL CHICAGO, ILLINOIS SP American Coll Cardiol C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0735-1097 J9 J AM COLL CARDIOL JI J. Am. Coll. Cardiol. PD MAR 19 PY 2003 VL 41 IS 6 SU A BP 111A EP 112A PG 2 WC Cardiac & Cardiovascular Systems SC Cardiovascular System & Cardiology GA 657LW UT WOS:000181669500483 ER PT J AU Schlegel, TT Gedevanishvili, A Ahmed, N Rahman, A Bungo, MW AF Schlegel, TT Gedevanishvili, A Ahmed, N Rahman, A Bungo, MW TI Newly developed high frequency QRS electrocardiograph in the detection of coronary disease SO JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY LA English DT Meeting Abstract CT 52nd Annual Scientific Session of the American-College-of-Cardiology CY MAR 30-APR 02, 2003 CL CHICAGO, ILLINOIS SP American Coll Cardiol C1 Univ Texas, Houston, TX USA. NASA Johnson Space Ctr, Houston, TX USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0735-1097 J9 J AM COLL CARDIOL JI J. Am. Coll. Cardiol. PD MAR 19 PY 2003 VL 41 IS 6 SU A BP 121A EP 122A PG 2 WC Cardiac & Cardiovascular Systems SC Cardiovascular System & Cardiology GA 657LW UT WOS:000181669500526 ER PT J AU Khazanov, GV Liemohn, MW Newman, TS Fok, MC Spiro, RW AF Khazanov, GV Liemohn, MW Newman, TS Fok, MC Spiro, RW TI Self-consistent magnetosphere-ionosphere coupling: Theoretical studies SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE magnetic storms; ring current; electric fields; numerical simulations ID RING CURRENT IONS; EARTHS MAGNETOSPHERE; PLASMA SHEET; SOLAR-WIND; STORM-TIME; MODEL; SUBSTORM; ENERGY; CONDUCTANCES; SIMULATION AB [1] A theoretical examination of the electrodynamical interaction between the ionosphere and the inner magnetosphere is presented. A self-consistent ring current (RC) model has been developed that couples the electron and ion magnetospheric dynamics with the calculation of the electric field. Two new features were taken into account in order to close the self-consistent magnetosphere-ionosphere coupling loop. First, in addition to the RC ions, we have solved an electron kinetic equation in our model. Second, using the relation of Galand and Richmond [2001], we have calculated the height integrated ionospheric conductances as a function of the precipitated high energy magnetospheric electrons and ions that are produced by our model. To validate the results of our model we simulate the magnetic storm of May 2, 1986, a storm that has been comprehensively studied by Fok et al. [2001], and have compared our results with different theoretical approaches. The self-consistent inclusion of the hot electrons and their effect on the conductance results in deeper penetration of the magnetospheric electric field. In addition, a slight westward rotation of the potential pattern (compared to previous self-consistent results) is evident in the inner magnetosphere. These effects change the hot plasma distribution, especially by allowing increased access of plasma sheet ions and electrons to low L shells. These results are consistent with recent observations from the IMAGE satellite. C1 NASA, Natl Space Sci & Technol Ctr, George C Marshall Space Flight Ctr, Huntsville, AL 35805 USA. Univ Michigan, Space Phys Res Lab, Ann Arbor, MI 48176 USA. Univ Alabama, Dept Comp Sci, Huntsville, AL 35806 USA. NASA, Extraterr Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Rice Univ, Dept Phys & Astron, Houston, TX 77005 USA. RP Khazanov, GV (reprint author), NASA, Natl Space Sci & Technol Ctr, George C Marshall Space Flight Ctr, Huntsville, AL 35805 USA. RI Fok, Mei-Ching/D-1626-2012; Liemohn, Michael/H-8703-2012; feggans, john/F-5370-2012 OI Liemohn, Michael/0000-0002-7039-2631; NR 35 TC 25 Z9 25 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 MAR 18 PY 2003 VL 108 IS A3 AR 1122 DI 10.1029/2002JA009624 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 667JK UT WOS:000182228300004 ER PT J AU Okamoto, K Loncar, M Yoshie, T Scherer, A Qiu, YM Gogna, P AF Okamoto, K Loncar, M Yoshie, T Scherer, A Qiu, YM Gogna, P TI Near-field scanning optical microscopy of photonic crystal nanocavities SO APPLIED PHYSICS LETTERS LA English DT Article ID LASER; MODE AB Near-field scanning optical microscopy was used to observe high-resolution images of confined modes and photonic bands of planar photonic crystal (PPC) nanocavities fabricated in active InGaAsP material. We have observed the smallest optical cavity modes, which are intentionally produced by fractional edge dislocation high-Q cavity designs. The size of the detected mode was roughly four by three lattice spacings. We have also observed extended dielectric-band modes of the bulk PPC surrounding the nanocavity by geometrically altering the bands in emission range and eliminating localized modes out of the emission range. (C) 2003 American Institute of Physics. C1 CALTECH, Dept Elect Engn, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Situ Technol & Expt Syst Sect, Pasadena, CA 91109 USA. RP Okamoto, K (reprint author), CALTECH, Dept Elect Engn, Pasadena, CA 91125 USA. RI Yoshie, Tomoyuki/C-3567-2008; Okamoto, Koichi/D-7695-2014 OI Okamoto, Koichi/0000-0002-2658-3000 NR 17 TC 39 Z9 39 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAR 17 PY 2003 VL 82 IS 11 BP 1676 EP 1678 DI 10.1063/1.1559646 PG 3 WC Physics, Applied SC Physics GA 653NF UT WOS:000181442300010 ER PT J AU Gonzalez, RR Sullivan, P Staab, JE Blanchard, LA Matthew, CB Matthew, WT Gonzalez, JA Lugg, DJ AF Gonzalez, RR Sullivan, P Staab, JE Blanchard, LA Matthew, CB Matthew, WT Gonzalez, JA Lugg, DJ TI Thermoregulatory responses to cold stress before and after Antarctic winter exposure SO FASEB JOURNAL LA English DT Meeting Abstract CT Experimental Biology 2003 Meeting CY APR 11-15, 2003 CL SAN DIEGO, CALIFORNIA C1 USA, Inst Res, Div Chief, Natick, MA 01760 USA. AAD, Kingston, Tas, Australia. NASA, HQ, Extreme Med, Code AM, Washington, DC 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 MAR 17 PY 2003 VL 17 IS 5 SU S BP A1267 EP A1267 PN 2 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA 659UY UT WOS:000181796902422 ER PT J AU Schneider, SM Gernhardt, M Loftin, K AF Schneider, SM Gernhardt, M Loftin, K TI Characterization of an exercise prebreathe protocol to prevent compression sickness (DCS) in astronauts SO FASEB JOURNAL LA English DT Meeting Abstract CT Experimental Biology 2003 Meeting CY APR 11-15, 2003 CL SAN DIEGO, CALIFORNIA C1 Univ New Mexico, Albuquerque, NM 87131 USA. NASA, Houston, TX USA. Old Dominion Univ, Dept Elect & Comp Engn, Norfolk, VA 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 MAR 17 PY 2003 VL 17 IS 5 SU S BP A947 EP A947 PN 2 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA 659UY UT WOS:000181796900909 ER PT J AU Stenger, MB McClendon, J Randall, D Brown, D Patwardhan, A Moore, F Greenleaf, J Burgess, D Knapp, CF AF Stenger, MB McClendon, J Randall, D Brown, D Patwardhan, A Moore, F Greenleaf, J Burgess, D Knapp, CF TI Heart rate-arterial pressure relationship in the human response to head-up tilt before and after artificial gravity training SO FASEB JOURNAL LA English DT Meeting Abstract CT Experimental Biology 2003 Meeting CY APR 11-15, 2003 CL SAN DIEGO, CALIFORNIA C1 Univ Kentucky, Ctr Biomed Engn, Lexington, KY 40506 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Asbury Coll, Wilmore, KY 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 MAR 17 PY 2003 VL 17 IS 5 SU S BP A946 EP A946 PN 2 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA 659UY UT WOS:000181796900904 ER PT J AU Wade, CE Moran, MM Fuller, PM Hobin-Higgins, T Baer, LA Stein, TP Fuller, CA AF Wade, CE Moran, MM Fuller, PM Hobin-Higgins, T Baer, LA Stein, TP Fuller, CA TI Effect of age on sympathetic activity in response to increased body weight induced by exposure to hypergravity SO FASEB JOURNAL LA English DT Meeting Abstract CT Experimental Biology 2003 Meeting CY APR 11-15, 2003 CL SAN DIEGO, CALIFORNIA C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Med & Dent New Jersey, Stratford, NJ USA. Univ Calif Davis, Davis, CA 95616 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 MAR 17 PY 2003 VL 17 IS 5 SU S BP A934 EP A935 PN 2 PG 2 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA 659UY UT WOS:000181796900849 ER PT J AU Gargano, P Mosca, H Bozzolo, G Noebe, RD AF Gargano, P Mosca, H Bozzolo, G Noebe, RD TI Atomistic modeling of RuAl and (RuNi)Al alloys SO SCRIPTA MATERIALIA LA English DT Article DE modelling; intermetallic phases; aluminium alloys; Monte Carlo techniques; ruthenium ID HIGH-TEMPERATURE ALLOYS; MECHANICAL-PROPERTIES; COHESIVE PROPERTIES; INTERMETALLIC COMPOUNDS; SUBSTITUTIONAL SOLUTES; ELECTRONIC-STRUCTURE; ALRU; ADDITIONS; STABILITY; PHASE AB Atomistic modeling of RuAl and RuAlNi alloys is performed. The BFS method for alloys and its first-principles-based parameters are tested by comparing to the lattice parameter and energy of formation of B2 RuAl and (Ru50-xNix)Al-50 alloys as a function of Ni concentration. Additional tests include Monte Carlo simulations for compositions close to Ru25Ni25Al50 showing no obvious evidence of a miscibility gap and separation of the individual B2 phases. (C) 2003 Published by Elsevier Science Ltd. on behalf of Acta Materialia Inc. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Comis Nacl Energia Atom, Ctr Atom Constituyentes, UA Mat, RA-1429 Buenos Aires, DF, Argentina. FIUBA, DTO Ingn Mecan & Naval, RA-1063 Buenos Aires, DF, Argentina. Ohio Aerosp Inst, Cleveland, OH 44142 USA. RP Bozzolo, G (reprint author), NASA, Glenn Res Ctr, Lewis Field,Mail Stop 23-2,21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 36 TC 24 Z9 24 U1 1 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6462 J9 SCRIPTA MATER JI Scr. Mater. PD MAR 17 PY 2003 VL 48 IS 6 BP 695 EP 700 AR PII S1359-6462(02)00556-0 DI 10.1016/S1359-6462(02)00556-0 PG 6 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 653AM UT WOS:000181413100008 ER PT J AU Atlas, D Williams, CR AF Atlas, D Williams, CR TI Radar echoes from lightning and their microphysical environment SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID CONVECTIVE CELLS; ELECTRIFICATION; PRECIPITATION AB [1] A UHF Profiler radar has detected lightning echoes which occurred preferentially in a "balance layer'', the stratum of mean zero Doppler velocity with rising small ice particles and falling graupel and hail, thus providing the conditions for collisional charging and lightning. The results support prior findings of the role of the balance layer in lightning generation. The 32.8 cm Profiler radar is particularly well suited for these observations because the lightning echoes are not masked by the precipitation echoes, thus allowing simultaneous measurement of the microphysical and kinematic properties. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Colorado, Boulder, CO 80309 USA. NOAA, CIRES, Aeron Lab, Boulder, CO 80305 USA. RP Atlas, D (reprint author), NASA, Goddard Space Flight Ctr, Code 912, Greenbelt, MD 20771 USA. RI Williams, Christopher/A-2723-2015 OI Williams, Christopher/0000-0001-9394-8850 NR 20 TC 3 Z9 3 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 MAR 15 PY 2003 VL 30 IS 5 AR 1262 DI 10.1029/2002GL016521 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 665ZX UT WOS:000182152100006 ER PT J AU Taleb, EH Druyan, LM AF Taleb, EH Druyan, LM TI Relationships between rainfall and West African wave disturbances in station observations SO INTERNATIONAL JOURNAL OF CLIMATOLOGY LA English DT Article DE African waves; Sahel rainfall; West African monsoon; wavelets ID ATLANTIC AB Morlet wavelets of the meridional component of daily radiosonde wind observations above four West Africa stations were constructed for May-September seasons, 1950-84, at three vertical levels. The passage of African wave disturbances (AWDs) at each station was detected as statistically significant wavelet amplitudes within two spectral bands. The detected AWD activity, or lack of it, was compared with the precipitation record at each station. Results demonstrate that AWDs account for only a proportion of the seasonal rainfall, implying that other precipitation triggers are also important. In addition, the analysis finds that many AWD traversals fail to initiate heavy rainfall at the selected stations. At Niamey, the average precipitation amount per wave had a positive trend between 1953 and 1978. With few exceptions, seasonal precipitation totals were not correlated with the number of days on which AWDs were detected. Although the seasonal average precipitation amount per AWD day exhibited a positive trend at Niamey between 1953 and 1978, there was no corresponding interannual trend in total seasonal precipitation. Copyright (C) 2003 Royal Meteorological Society. C1 Columbia Univ, Earth Inst, Ctr Climate Syst Res, New York, NY 10025 USA. Free Univ Brussels, Dept Geog, B-1050 Brussels, Belgium. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Druyan, LM (reprint author), Columbia Univ, Earth Inst, Ctr Climate Syst Res, 2880 Broadway, New York, NY 10025 USA. NR 12 TC 15 Z9 15 U1 0 U2 0 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0899-8418 J9 INT J CLIMATOL JI Int. J. Climatol. PD MAR 15 PY 2003 VL 23 IS 3 BP 305 EP 313 DI 10.1002/joc.883 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 654HV UT WOS:000181490200005 ER PT J AU Parrish, A Boyd, IS Zawodny, JM Thomason, LW Bodeker, GE Connor, BJ AF Parrish, A Boyd, IS Zawodny, JM Thomason, LW Bodeker, GE Connor, BJ TI Relative performance of three SAGE-II data versions under high aerosol conditions based on comparisons with microwave and ozonesonde profiles measured at two NDSC sites SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID NEW-ZEALAND; TEMPERATURE; LAUDER AB [1] Intercomparisons between SAGE-II data versions 5.93, 5.96, and 6.1 with microwave ozone and ozonesonde measurements made at the NDSC primary station at Lauder, New Zealand, and with microwave measurements made at the NDSC complementary station at Table Mountain, California, are reported on here. The focus is on SAGE-II measurement performance during the period when stratospheric aerosol levels were substantially elevated following the 1991 Mt. Pinatubo eruption. SAGE-II ozone retrievals are potentially affected by aerosol levels and size distributions because extinction due to aerosol must be estimated and subtracted from the measured total extinction in the 600 nm ozone channel to determine the ozone amount; the microwave and ozonesonde comparison measurements are aerosol insensitive. Around 10-25 hPa, the newer algorithm versions retain a tendency toward extinction-dependent bias previously reported for version 5.9; this dependence may be larger than previously indicated at moderately high aerosol levels. In the 30-40 hPa range, the extinction dependence of version 6.1 (and, usually, version 5.96) data is a few times less than that of version 5.93. Between about 30 and 80 hPa most points at moderately elevated aerosol extinctions are less affected than in version 5.93, and these are fewer and/or less affected in version 6.1 than in version 5.96. When aerosols are at background levels, the precisions of version 5.93 and 5.96 measurements are at least somewhat better, around 30 hPa, than the errors provided with the data. The errors provided with version 6.1 data are substantially smaller than in previous versions, and small enough that the experimental sensitivity was insufficient to draw conclusions regarding the actual precision in comparison to the error values. C1 Univ Massachusetts, Five Coll Radio Astron Observ, Amherst, MA 01003 USA. NIWA Environm Res Inst, Groton, CT USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Natl Inst Water & Atmospher Res, Lauder, Central Otago, New Zealand. RP Parrish, A (reprint author), Univ Massachusetts, Five Coll Radio Astron Observ, Amherst, MA 01003 USA. NR 14 TC 0 Z9 0 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 MAR 15 PY 2003 VL 108 IS D5 AR 4172 DI 10.1029/2002JD002461 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 666AY UT WOS:000182154500002 ER PT J AU Schauffler, SM Atlas, EL Donnelly, SG Andrews, A Montzka, SA Elkins, JW Hurst, DF Romashkin, PA Dutton, GS Stroud, V AF Schauffler, SM Atlas, EL Donnelly, SG Andrews, A Montzka, SA Elkins, JW Hurst, DF Romashkin, PA Dutton, GS Stroud, V TI Chlorine budget and partitioning during the Stratospheric Aerosol and Gas Experiment (SAGE) III Ozone Loss and Validation Experiment (SOLVE) SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE chlorine; stratosphere; halogens; CFCs; HCFCs; solvents ID ARCTIC POLAR VORTEX; IN-SITU OBSERVATIONS; TRACE GASES; ORGANIC-COMPOUNDS; VERTICAL-DISTRIBUTION; AIRCRAFT MEASUREMENTS; TROPICAL TROPOPAUSE; UPPER TROPOSPHERE; METHYL-BROMIDE; NITROUS-OXIDE AB [1] The amount of chlorine in the stratosphere has a direct influence on the magnitude of chlorine-catalyzed ozone loss. A comprehensive suite of organic source gases of chlorine in the stratosphere was measured during the NASA Stratospheric Aerosol and Gas Experiment (SAGE) III Ozone Loss and Validation Experiment (SOLVE) campaign in the arctic winter of 2000. Measurements included chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), halon 1211, solvents, methyl chloride, N2O, and CH4. Inorganic chlorine contributions from each compound were calculated using the organic chlorine measurements, mean age of air, tropospheric trends, and a method to account for mixing in the stratosphere. Total organic chlorine measured at tropospheric levels of N2O was on the order of 3500 ppt. Total calculated inorganic chlorine at a N2O mixing ratio of 50 ppb (corresponding to a mean age of 5.5 years) was on the order of 3400 ppt. CFCs were the largest contributors to total organic chlorine (55-70%) over the measured N2O range (50-315 ppb), followed by CH3Cl (15%), solvents (5-20%), and HCFCs (5-25%). CH3Cl contribution was consistently about 15% across the organic chlorine range. Contributions to total calculated inorganic chlorine at 50 ppb N2O were 58% from CFCs, 24% from solvents, 16% from CH3Cl, and 2% from HCFCs. Updates to fractional chlorine release values for each compound relative to CFC 11 were calculated from the SOLVE measurements. An average value of 0.58 was calculated for the fractional chlorine release of CFC 11 over the 3-4 year mean age range, which was lower than the previous value of 0.80. The fractional chlorine release values for HCFCs 141b and 142b relative to CFC 11 were significantly lower than previous calculations. C1 Natl Ctr Atmospher Res, Boulder, CO 80307 USA. NASA, Goddard Space Flight Facil, Greenbelt, MD 20771 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. RP Schauffler, SM (reprint author), Natl Ctr Atmospher Res, POB 3000, Boulder, CO 80307 USA. EM sues@acd.ucar.edu RI Andrews, Arlyn/K-3427-2012; Atlas, Elliot/J-8171-2015; Hurst, Dale/D-1554-2016 OI Hurst, Dale/0000-0002-6315-2322 NR 80 TC 52 Z9 52 U1 1 U2 18 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAR 15 PY 2003 VL 108 IS D5 AR 4173 DI 10.1029/2001JD002040 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 666AY UT WOS:000182154500001 ER PT J AU Araujo-Pradere, EA Fuller-Rowell, TJ Bilitza, D AF Araujo-Pradere, EA Fuller-Rowell, TJ Bilitza, D TI Validation of the STORM response in IRI2000 SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE ionosphere; empirical modeling; geomagnetic storm; IRI 2000; STORM model ID INTERNATIONAL REFERENCE IONOSPHERE; GEOMAGNETIC STORMS; THERMOSPHERE AB [1] The latest version of the International reference ionosphere, IRI2000 [Bilitza, 2001], contains a dependence on geomagnetic activity based on an empirical storm-time ionospheric correction model (STORM) [Araujo-Pradere et al., 2002]. The new storm correction in IRI is driven by the previous time history (33 hours) of ap and is designed to scale the normal quiet-time F layer critical frequency (f(o)F(2)) to account for storm-time changes in the ionosphere. An extensive validation of IRI2000 has been performed during geomagnetic storm conditions to determine the validity of the new algorithms. The quality of the storm-time correction has been evaluated by comparing the model with the observed ionospheric response during all the geomagnetic storms with ap > 150 in 2000 and 2001, a total of 14 intervals. The model output was compared with the actual ionospheric response for all available ionosonde stations for each storm. The comparisons show that the model captures the decreases in electron density particularly well in summer and equinox conditions. To quantify the improvement in IRI2000, the root-mean-square error has been evaluated and compared with the previous version of IRI, which had no geomagnetic dependence. The results indicate that IRI2000 has almost a 30% improvement over IRI95 during the storm days and is able to capture more than 50% of the increase in variability, above quiet times, due to the storms. C1 NOAA, Space Environm Ctr, Boulder, CO 80305 USA. NASA, Goddard Space Flight Ctr, Raytheon ITSS, Greenbelt, MD 20771 USA. RP Araujo-Pradere, EA (reprint author), NOAA, Space Environm Ctr, 325 Broadway, Boulder, CO 80305 USA. NR 19 TC 31 Z9 32 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 MAR 15 PY 2003 VL 108 IS A3 AR 1120 DI 10.1029/2002JA009720 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 667BV UT WOS:000182211700002 ER PT J AU Harris, JD Banger, KK Scheiman, DA Smith, MA Jin, MHC Hepp, AF AF Harris, JD Banger, KK Scheiman, DA Smith, MA Jin, MHC Hepp, AF TI Characterization of CuInS2 films prepared by atmospheric pressure spray chemical vapor deposition SO MATERIALS SCIENCE AND ENGINEERING B-SOLID STATE MATERIALS FOR ADVANCED TECHNOLOGY LA English DT Article DE CuInS2; solar cells; thin film; photoelectrochemical analysis; spray CVD ID SINGLE-SOURCE PRECURSORS; THIN-FILMS; SOLAR-CELLS; ELECTRODEPOSITION; MICROSTRUCTURE; PYROLYSIS; PROGRESS; DEVICES AB Copper indium. disulfide films were deposited by atmospheric pressure spray chemical vapor deposition. (CVD). Films were deposited at 390 degreesC using [(PPh3)(2)CuIn(SEt)(4)] as a single source precursor in an argon atmosphere. The films range in thickness from 0.75 to 1.0 mum and exhibit a crystallographic gradient, with the leading edge having a (220) preferred orientation and the trailing edge having a (112) orientation. Schottky diodes prepared by thermal evaporation of aluminum contacts onto the CuInS2 yielded diodes for films that were annealed at 600 degreesC. The photoresponse of several films was measured by photoelectrochemical analysis in an aqueous, acidic, electrolyte. Prolonged exposure of the films to the electrolyte caused a decreased photoresponse. Complete solar cells were prepared using annealed films and had the (top down) composition of Al/ZnO/CdS/CuInS2/Mo/Glass. The short-circuit current (I-sc), open-circuit voltage (V-oc) maximum power Output (P-max), current at P-max (I-max), voltage at P-max (V-max), fill factor (FF) and efficiency (eta) were 5.25 mA, 304 mV, 0.470 mW, 2.92 mA, 161 mV, 29.4 and 0.68%, respectively, for a 0.5 cm(2) cell under simulated AMO illumination. (C) 2003 Elsevier Science B.V. All rights reserved. C1 NASA, Glenn Res Ctr, Thin Film Technol Grp, Cleveland, OH 44135 USA. Ohio Aerosp Inst, Brookpark, OH 44142 USA. Cleveland State Univ, Dept Chem, Cleveland, OH 44115 USA. RP Hepp, AF (reprint author), NASA, Glenn Res Ctr, Thin Film Technol Grp, 21000 Brookpark Rd, Cleveland, OH 44135 USA. NR 30 TC 30 Z9 31 U1 2 U2 8 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5107 J9 MAT SCI ENG B-SOLID JI Mater. Sci. Eng. B-Solid State Mater. Adv. Technol. PD MAR 15 PY 2003 VL 98 IS 2 BP 150 EP 155 DI 10.1016/S0921-5107(03)00041-2 PG 6 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA 676XM UT WOS:000182777900011 ER PT J AU Maslov, AV Citrin, DS AF Maslov, AV Citrin, DS TI Enhancement of the Aharonov-Bohm effect of neutral excitons in semiconductor nanorings with an electric field SO PHYSICAL REVIEW B LA English DT Article ID OPTICAL-ABSORPTION; QUANTUM RING AB This work demonstrates that the Aharonov-Bohm effect for excitons, practically indistinguishable from the numerical noise without an applied electric field, becomes clearly evident in the optical absorption once the electric field is applied in the plane containing the nanoring. The enhancement arises as a result of the field-induced delocalization of the relative electron-hole motion around the entire ring. The excitonic effects are essential to describe even qualitatively the absorption spectra. C1 Georgia Inst Technol, Sch Elect & Comp Engn, Atlanta, GA 30332 USA. RP Maslov, AV (reprint author), NASA, Ames Res Ctr, MS 229-1, Moffett Field, CA 94035 USA. RI Maslov, Alexey/E-5158-2011 OI Maslov, Alexey/0000-0002-7835-2474 NR 16 TC 42 Z9 42 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 J9 PHYS REV B JI Phys. Rev. B PD MAR 15 PY 2003 VL 67 IS 12 AR 121304 DI 10.1103/PhysRevB.67.121304 PG 4 WC Physics, Condensed Matter SC Physics GA 666CL UT WOS:000182158000014 ER PT J AU Wei, CY Cho, KJ Srivastava, D AF Wei, CY Cho, KJ Srivastava, D TI Tensile strength of carbon nanotubes under realistic temperature and strain rate SO PHYSICAL REVIEW B LA English DT Article ID ACCELERATED DYNAMICS; SINGLE; COMPRESSION; GROWTH; ROPES AB A transition state theory based predictive model is developed for the tensile failure of carbon nanotubes (CNT's). We show that the tensile yield strain has linear dependence on the activation energy and the temperature, and has a logarithmic dependence on the strain rate. Based on the parameters fitted from strain rate and temperature-dependent simulations within a wide range of molecular-dynamics time scales, the model predicts that a defect-free micrometer long single-wall nanotube at 300 K, stretched with a strain rate of 1%/h, yields at about 9+/-1% tensile strain for small diameter CNT's, and about 2-3 % higher for larger diameter CNT's. This is in good agreement with recent experimental findings. C1 Stanford Univ, Dept Mech Engn, Stanford, CA 94305 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Wei, CY (reprint author), Stanford Univ, Dept Mech Engn, Stanford, CA 94305 USA. NR 24 TC 139 Z9 143 U1 7 U2 35 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 J9 PHYS REV B JI Phys. Rev. B PD MAR 15 PY 2003 VL 67 IS 11 AR 115407 DI 10.1103/PhysRevB.67.115407 PG 6 WC Physics, Condensed Matter SC Physics GA 663YP UT WOS:000182035100125 ER PT J AU Tanner, AB Riley, AL AF Tanner, AB Riley, AL TI Design and performance of a high-stability water vapor radiometer SO RADIO SCIENCE LA English DT Article DE microwave radiometer; water vapor; radiometer design ID CALIBRATION AB [1] The design of two new high-stability microwave water vapor radiometers is presented along with a performance evaluation. The radiometers operate next to a spacecraft tracking station at NASA's Goldstone facility in California, where they will be used to calibrate tropospheric path delay fluctuations during an upcoming gravity-wave search experiment (GWE) involving the Cassini spacecraft. Observing frequencies of the radiometers are 22.2, 23.8, and 31.4 GHz, and the antenna beam width is 1degrees. The instruments are room temperature Dicke radiometers with additive noise injection for gain calibration. Design highlights include: (1) a practical temperature control system capable of stabilizing the entire receiver to a few millikelvin from day to night; (2) redundant noise diode injection circuits with 30 ppm RF power stability; and (3) a voice coil actuated waveguide vane attenuator which is used as a high-performance Dicke switch. Performance of the radiometers is evaluated from intercomparisons of the two radiometers and from continuous tip curve calibrations spanning nearly 1 year. Structure function analysis of the intercomparison data indicates that the brightness temperature stability of these radiometers is better than 0.01 K on 1000-10,000 s timescales. Analysis of tip curve calibrations indicates RMS errors of similar to0.05 K on 30-day timescales and 0.15 K on 1-year timescales. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Tanner, AB (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 246-101, Pasadena, CA 91109 USA. EM alan.b.tanner@jpl.nasa.gov; a.lance.riley@jpl.nasa.gov NR 10 TC 16 Z9 16 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0048-6604 J9 RADIO SCI JI Radio Sci. PD MAR 15 PY 2003 VL 38 IS 3 AR 8050 DI 10.1029/2002RS002673 PG 17 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA 667CG UT WOS:000182212800001 ER PT J AU Atwell, AR Okojie, RS Kornegay, KT Roberson, SL Beliveau, A AF Atwell, AR Okojie, RS Kornegay, KT Roberson, SL Beliveau, A TI Simulation, fabrication and testing of bulk micromachined 6H-SiC high-g piezoresistive accelerometers SO SENSORS AND ACTUATORS A-PHYSICAL LA English DT Article DE silicon carbide; MEMS; accelerometer; shock testing; piezoresistivity ID SENSORS; SILICON AB We report the utilization of key design parameters to simulate, batch-fabricate and evaluate first-generation single crystal 6H-SiC piezoresistive accelerometers for extreme impact applications. High-g simulation results predicted safe operation above 100,000 x g and preliminary experimental tests were successfully performed to 40,000 x g. Sensitivities ranging between 50 and 343 nV/g were measured for differing accelerometer sensing elements. Non-linear behavior was observed over the shock range relative to the commercial benchmark accelerometer. These initial results offer promise for the use of 6H-SiC accelerometers in extreme impact sensing. (C) 2002 Elsevier Science B.V. All rights reserved. C1 NASA, Glenn Res Ctr, Instrumentat Controls Div, Cleveland, OH 44135 USA. Cornell Univ, Sch Elect & Comp Engn, Ithaca, NY 14853 USA. USAF, Res Lab, Munit Directorate, MNMF,Fuzes Branch, Eglin AFB, FL 32542 USA. Appl Res Associates, Ft Walton Beach, FL 32547 USA. RP Atwell, AR (reprint author), Inst Def Anal, OED, 4850 Mark Ctr Dr, Alexandria, VA 22311 USA. NR 15 TC 48 Z9 54 U1 1 U2 15 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0924-4247 J9 SENSOR ACTUAT A-PHYS JI Sens. Actuator A-Phys. PD MAR 15 PY 2003 VL 104 IS 1 BP 11 EP 18 AR PII S0924-4247(02)00436-3 DI 10.1016/S0924-4247(02)00436-3 PG 8 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 649YT UT WOS:000181236100003 ER PT J AU Baer, LA Chowdhury, J Grindeland, RE Wade, CE Ronca, AE AF Baer, LA Chowdhury, J Grindeland, RE Wade, CE Ronca, AE TI Reduced body weights of rat pups reared in hypergravity: potential contributions of the maternal/offspring system SO FASEB JOURNAL LA English DT Meeting Abstract CT Experimental Biology 2003 Meeting CY APR 11-15, 2003 CL SAN DIEGO, CALIFORNIA C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Alberta, Edmonton, AB T6G 2M7, Canada. 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 MAR 14 PY 2003 VL 17 IS 4 SU S BP A452 EP A452 PN 1 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA 658QZ UT WOS:000181733102140 ER PT J AU Lane, HW Davis-Street, J Smith, SM AF Lane, HW Davis-Street, J Smith, SM TI Dietary sodium increases calcium losses during space flight SO FASEB JOURNAL LA English DT Meeting Abstract CT Experimental Biology 2003 Meeting CY APR 11-15, 2003 CL SAN DIEGO, CALIFORNIA C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Enterprise Advisory Serv, 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 MAR 14 PY 2003 VL 17 IS 4 SU S BP A726 EP A726 PN 1 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA 658QZ UT WOS:000181733103414 ER PT J AU Smith, SM Dillon, EL DeKerlegand, DE Davis-Street, JE AF Smith, SM Dillon, EL DeKerlegand, DE Davis-Street, JE TI Collagen crosslink variability: effect of sample type on variability SO FASEB JOURNAL LA English DT Meeting Abstract CT Experimental Biology 2003 Meeting CY APR 11-15, 2003 CL SAN DIEGO, CALIFORNIA C1 NASA, Lyndon B Johnson Space Ctr, Natl Biochem Lab, Houston, TX 77058 USA. Enterprise Advisory Serv, Houston, TX USA. RI Dillon, Edgar/B-2495-2008 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 MAR 14 PY 2003 VL 17 IS 4 SU S BP A723 EP A723 PN 1 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA 658QZ UT WOS:000181733103400 ER PT J AU Tou, JC Grindeland, RE Baer, LA Wade, CE AF Tou, JC Grindeland, RE Baer, LA Wade, CE TI Effects of simulated hypogravity and diet on estrous cycling in rats SO FASEB JOURNAL LA English DT Meeting Abstract CT Experimental Biology 2003 Meeting CY APR 11-15, 2003 CL SAN DIEGO, CALIFORNIA C1 NASA, Ames Res Ctr, 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 MAR 14 PY 2003 VL 17 IS 4 SU S BP A450 EP A450 PN 1 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA 658QZ UT WOS:000181733102130 ER PT J AU Villareal, J Baer, LA Wade, CE Ronca, AE AF Villareal, J Baer, LA Wade, CE Ronca, AE TI In-situ analysis of intrauterine pressure in freely moving pregnant and parturient rats SO FASEB JOURNAL LA English DT Meeting Abstract CT Experimental Biology 2003 Meeting CY APR 11-15, 2003 CL SAN DIEGO, CALIFORNIA 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 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 MAR 14 PY 2003 VL 17 IS 4 SU S BP A452 EP A453 PN 1 PG 2 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA 658QZ UT WOS:000181733102141 ER PT J AU Li, CY Nelson, JR Koziana, JV AF Li, CY Nelson, JR Koziana, JV TI Cross-shelf passage of coastal water transport at the South Atlantic Bight observed with MODIS Ocean Color/SST SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article DE cross-shelf transport; transport passage; South Atlantic Bight ID SOUTHEASTERN UNITED-STATES; CONTINENTAL-SHELF AB [1] Images of cross-shelf fronts of ocean color parameters and Sea Surface Temperature (SST) of the South Atlantic Bight (SAB) area are presented and analyzed. The ocean color parameters (K-490 and suspended solid concentration) and SST clearly indicate a penetrating front originating from the coastal water within the inner shelf. The front is triangular shaped with its broad base on the coast and its sharp end penetrating into the outer shelf and merging into the Gulf Stream, depicting a passage of coastal water transport across the shelf. This passage changes in position and orientation (from southwest-northeast to west-east). The horizontal Ekman number was estimated to be outside the limit of baroclinic instability, suggesting that the process is deterministic. Thus, the water transport passage may play a significant role in a non-diffusive transport process of heat and land-derived biogeochemical materials. C1 Skidaway Inst Oceanog, Savannah, GA 31411 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Li, CY (reprint author), Skidaway Inst Oceanog, 10 Ocean Sci Circle, Savannah, GA 31411 USA. NR 14 TC 9 Z9 9 U1 1 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAR 14 PY 2003 VL 30 IS 5 AR 1257 DI 10.1029/2002GL016496 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 665ZW UT WOS:000182152000003 ER PT J AU Considine, DB Kawa, SR Schoeberl, MR Douglass, AR AF Considine, DB Kawa, SR Schoeberl, MR Douglass, AR TI N2O and NOy observations in the 1999/2000 Arctic polar vortex: Implications for transport processes in a CTM SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID OZONE LOSS; STRATOSPHERIC AIRCRAFT; SATELLITE-OBSERVATIONS; 3-DIMENSIONAL MODEL; WINTER STRATOSPHERE; TRACER TRANSPORT; DENITRIFICATION; SENSITIVITY; DEPLETION; NITROGEN AB [1] We compare the evolution of simulated NOy and N2O with observations made during the 1999/2000 NASA Stratospheric Aerosol and Gas Experiment (SAGE) III Ozone Loss and Validation Experiment/Third European Stratospheric Experiment on Ozone-2000 to understand the different effects of transport on these two species and evaluate model transport processes in the Arctic lower stratosphere during mid to late winter. The simulations were made with the Goddard Space Flight Center chemistry and transport model, driven by meteorological analyses from the Goddard Data Assimilation Office. In January, model NOy and N2O distributions agree well with observations, provided a substantial loss of NOy due to polar stratospheric cloud sedimentation is included in the model simulation. In late winter, model NOy is similar to2-3 times larger than observed, despite the continued reasonable agreement of N2O. Anomalously large vertical transport of NOy due to overly vigorous descent in the CTM is primarily responsible for the large late winter NOy mixing ratios. However, the rapid descent is not apparent in the evolution of modeled N2O and presumably other similar species due to compensating horizontal transport of N2O across the vortex edge, which results in the reasonable agreement between modeled and measured N2O at ER-2 altitudes throughout the winter. The need to properly represent the seasonal evolution of NOy when studying lower stratospheric polar wintertime photochemistry places strong constraints on the meteorological data used to drive global chemistry and transport models. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. NASA, Goddard Space Flight Ctr, Atmospher Chem & Dynam Branch, Greenbelt, MD 20771 USA. RP Considine, DB (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. EM d.b.considine@larc.nasa.gov RI Douglass, Anne/D-4655-2012; Kawa, Stephan/E-9040-2012 NR 40 TC 9 Z9 9 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 MAR 14 PY 2003 VL 108 IS D5 AR 4170 DI 10.1029/2002JD002525 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 666AU UT WOS:000182154100002 ER PT J AU Barnes, NP Axenson, TJ Reichle, DJ Walsh, BM AF Barnes, NP Axenson, TJ Reichle, DJ Walsh, BM TI Diode-pumped laser amplifiers: application to 0.946 mu m Nd : YAG SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID YTTRIUM ALUMINUM GARNET; 946 NM; ROOM-TEMPERATURE; PERFORMANCE; EFFICIENCY; OPERATION; EMISSION AB A diode-pumped laser amplifier model is derived from first principles and applied to a Nd:YAG amplifier operating on the (4F)(3/2) (to 4I)(9/2) transition at 0.946 mm. The effects of amplified spontaneous emission are included in the model and the addition of this effect is shown to produce better agreement with the data. The amplifier model includes effects of the transverse and longitudinal variation of the pump beam, transverse and longitudinal variation of the probe beam, and multiple passes of the probe beam. Experimental results obtained with a quasi four-level Nd:YAG amplifier operating at 0.946 mm are used to validate the model. The amplifier was evaluated as a function of the pump energy, the probe energy, the probe beam radius, the pulse repetition frequency and the temperature. For all of the experimental conditions, the experimental results and the model agree. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Sci & Technol Corp, Hampton, VA 23666 USA. RP Barnes, NP (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. EM n.p.barnes@larc.nasa.gov; t.j.axenson@larc.nasa.gov NR 20 TC 1 Z9 1 U1 1 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0953-4075 J9 J PHYS B-AT MOL OPT JI J. Phys. B-At. Mol. Opt. Phys. PD MAR 14 PY 2003 VL 36 IS 5 BP 879 EP 891 AR PII S0953-4075(03)53746-4 DI 10.1088/0953-4075/36/5/308 PG 13 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 665VR UT WOS:000182142400009 ER PT J AU Kumar, A Schubert, SD Suarez, MS AF Kumar, A Schubert, SD Suarez, MS TI Variability and predictability of 200-mb seasonal mean heights during summer and winter SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE seasonal predictability; ENSO response; ENSO SSTs ID SEA-SURFACE TEMPERATURE; ATMOSPHERIC RESPONSE; CLIMATE VARIABILITY; ANNUAL CYCLE; CONVECTION; PREDICTION; ANOMALIES AB In this paper a comparison of the variability and predictability of 200-mb seasonal mean heights for winter and summer is made based upon atmospheric general circulation model (AGCM) simulations. Simulations from two different AGCMs for the 1982-1999 period are used. The magnitude of seasonal predictability for the winter and summer is found to be similar. The spatial characteristics of seasonal predictability, however, had some interesting differences. For the respective hemisphere's summer the extratropical zonal mean heights had an appreciable contribution towards seasonal predictability, whereas for the winter season, predictability was dominated by eddy heights. There were also interesting interhemispheric differences in seasonal variability and predictability which are attributed to an interplay between the seasonal cycle of El Nino-Southern Oscillation SST anomalies and the seasonal cycle of mean atmospheric circulation which governs the dynamics of tropical-extratropical interactions. C1 Natl Ctr Environm Predict, Climate Predict Ctr, Camp Springs, MD 20746 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Kumar, A (reprint author), Natl Ctr Environm Predict, Climate Predict Ctr, 5200 Auth Rd,Room 806-H, Camp Springs, MD 20746 USA. EM arun.kumar@noaa.gov; schubert@dao.gsfc.nasa.gov; max.suarez@gsfc.nasa.gov NR 20 TC 29 Z9 34 U1 1 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 MAR 13 PY 2003 VL 108 IS D5 AR 4169 DI 10.1029/2002JD002728 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 666AQ UT WOS:000182153800006 ER PT J AU Pilewskie, P Pommier, J Bergstrom, R Gore, W Howard, S Rabbette, M Schmid, B Hobbs, PV Tsay, SC AF Pilewskie, P Pommier, J Bergstrom, R Gore, W Howard, S Rabbette, M Schmid, B Hobbs, PV Tsay, SC TI Solar spectral radiative forcing during the Southern African Regional Science Initiative SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE solar radiation; aerosols; climate; radiometric measurements ID OPTICAL-PROPERTIES; AEROSOL; ABSORPTION; IRRADIANCE; CLOUDS AB [1] During the dry season component of the Southern African Regional Science Initiative (SAFARI) in late winter 2000, the net solar spectral irradiance was measured at flight levels throughout biomass burning haze layers. From these measurements, the flux divergence, fractional absorption, instantaneous heating rate, and absorption efficiency were derived. Two cases are examined: on 24 August 2000 off the coast of Mozambique in the vicinity of Inhaca Island and on 6 September 2000 in a very thick continental haze layer over Mongu, Zambia. The measured absolute absorption was substantially higher for the case over Mongu where the measured midvisible optical depth exceeded unity. Instantaneous heating from aerosol absorption was 4 K d(-1) over Mongu, Zambia and 1.5 K d(-1) near Inhaca Island, Mozambique. However, the spectral absorption efficiency was nearly identical for both cases. Although the observations over Inhaca Island preceded the "river of smoke'' from the southern African continent by nearly 2 weeks, the evidence here suggests a continental influence in the lower tropospheric aerosol far from source regions of burning. C1 NASA, Ames Res Ctr, Div Earth Sci, Moffett Field, CA 94035 USA. Bay Area Environm Res Inst, Sonoma, CA USA. Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Pilewskie, P (reprint author), NASA, Ames Res Ctr, Div Earth Sci, Moffett Field, CA 94035 USA. EM ppilewskie@mail.arc.nasa.gov RI Tsay, Si-Chee/J-1147-2014 NR 20 TC 78 Z9 78 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 MAR 13 PY 2003 VL 108 IS D13 AR 8486 DI 10.1029/2002JD002411 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 666VG UT WOS:000182196700001 ER PT J AU Kara, AB Rochford, PA Hurlburt, HE AF Kara, AB Rochford, PA Hurlburt, HE TI Mixed layer depth variability over the global ocean SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article DE mixed layer; isothermal layer; seasonal cycle; temperature; salinity; verification ID EQUATORIAL PACIFIC-OCEAN; BARRIER-LAYER; NORTH-PACIFIC; SURFACE-LAYER; SOLAR-RADIATION; SKILL SCORES; SEA ICE; TEMPERATURE; ATLANTIC; SALINITY AB [1] The spatial and monthly variability of the climatological mixed layer depth (MLD) for the global ocean is examined using the recently developed Naval Research Laboratory (NRL) Ocean Mixed Layer Depth (NMLD) climatologies. The MLD fields are constructed using the subsurface temperature and salinity data from the World Ocean Atlas 1994 [Levitus et al., 1994; Levitus and Boyer, 1994]. To minimize the limitations of these global data in the MLD determination, a simple mixing scheme is introduced to form a stable water column. Using these new data sets, global MLD characteristics are produced on the basis of an optimal definition that employs a density-based criterion having a fixed temperature difference of DeltaT = 0.8degreesC and variable salinity. Strong seasonality of MLD is found in the subtropical Pacific Ocean and at high latitudes, as well as a very deep mixed layer in the North Atlantic Ocean in winter and a very shallow mixed layer in the Antarctic in all months. Using the climatological monthly MLD and isothermal layer depth (ILD) fields from the NMLD climatologies, an annual mean DeltaT field is presented, providing criteria for determining an ILD that is approximately equivalent to the optimal MLD. This enables MLD to be determined in cases where salinity data are not available. The validity of the correspondence between ILD and MLD is demonstrated using daily averaged subsurface temperature and salinity from two moorings: a Tropical Atmosphere Ocean array mooring in the western equatorial Pacific warm pool, where salinity stratification is important, and a Woods Hole Oceanographic Institute (WHOI) mooring in the Arabian Sea, where strongly reversing seasonal monsoon winds prevail. In the western equatorial Pacific warm pool the use of ILD criterion with an annual mean DeltaT value of 0.3degreesC yields comparable results with the optimal MLD, while large DeltaT values yield an overestimated MLD. An analysis of ILD and MLD in the WHOI mooring show that use of an incorrect DeltaT criterion for the ILD may underestimate or overestimate the optimal MLD. Finally, use of the spatial annual mean DeltaT values constructed from the NMLD climatologies can be used to estimate the optimal MLD from only subsurface temperature data via an equivalent ILD for any location over the global ocean. C1 Florida State Univ, Ctr Ocean Atmospher Predict Studies, Tallahassee, FL 32306 USA. USN, Res Lab, Div Oceanog, Stennis Space Ctr, Stennis Space Ctr, MS 39529 USA. RP Kara, AB (reprint author), Florida State Univ, Ctr Ocean Atmospher Predict Studies, Tallahassee, FL 32306 USA. NR 56 TC 151 Z9 156 U1 3 U2 42 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 MAR 13 PY 2003 VL 108 IS C3 AR 3079 DI 10.1029/2000JC000736 PG 15 WC Oceanography SC Oceanography GA 666VV UT WOS:000182197900005 ER PT J AU Mattioda, AL Hudgins, DM Bauschlicher, CW Rosi, M Allamandola, LJ AF Mattioda, AL Hudgins, DM Bauschlicher, CW Rosi, M Allamandola, LJ TI Infrared spectroscopy of matrix-isolated polycyclic aromatic compounds and their ions. 6. Polycyclic aromatic nitrogen heterocycles SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID HYDROCARBON CATIONS; PERDEUTERATED NAPHTHALENE; MODEL PAHS; SPECTRA; SUBSTITUTION; CARRIERS; BANDS; PHENANTHRENE; HYPOTHESIS; IONIZATION AB The matrix-isolation technique has been employed to measure the mid-infrared spectra of several polycyclic aromatic nitrogen heterocycles in both neutral and cationic forms. The species studied include: 7,8-benzoquinoline (C13H9N), 2-azapyrene (C15H9N), 1- and 2- azabenz[a]anthracene (C17H11N), and 1-, 2-, and 4-azachrysene (also C17H11N). The experimentally measured band frequencies and intensities for each molecule are tabulated and compared with their calculated values computed using density functional theory at the B3LYP/4-31G level. The overall agreement between experiment and theory is good, in keeping with previous investigations involving the parent aromatic hydrocarbons. Several interesting spectroscopic trends are found to accompany nitrogen substitution into the aromatic framework of these compounds. For the neutral species, the nitrogen atom produces a significant increase in the total integrated infrared intensity across the 1600-1100 cm(-1) region and plays an essential role in the molecular vibration that underlies an uncharacteristically intense, discrete feature that is observed near 1400 cm(-1) in the spectra of 7,8-benzoquinoline, 1-azabenz[a]anthracene, and 4-azachrysene. The origin of this enhanced infrared activity and the nature of the 1400 cm(-1) vibrational mode are explored. As a secondary result of the computations, the computed dipole moments and rotational constants for the species under study are reported. The dipole moments calculated are significantly stronger than those of the parent PAH and in principle could facilitate interstellar detection of these PAH related compounds. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Perugia, Dept Chem, CNR, Inst Mol Sci & Technol, I-06123 Perugia, Italy. RP Mattioda, AL (reprint author), NASA, Ames Res Ctr, MS 245-6, Moffett Field, CA 94035 USA. RI Rosi, Marzio/L-5748-2015 OI Rosi, Marzio/0000-0002-1264-3877 NR 41 TC 77 Z9 77 U1 1 U2 18 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 MAR 13 PY 2003 VL 107 IS 10 BP 1486 EP 1498 DI 10.1021/jp021938c PG 13 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 652UJ UT WOS:000181398800006 ER PT J AU Brooks, TF Humphreys, WM AF Brooks, TF Humphreys, WM TI Flap-edge aeroacoustic measurements and predictions SO JOURNAL OF SOUND AND VIBRATION LA English DT Article; Proceedings Paper CT AIAA/CEAS 6th Aeroacoustics Conference CY JUN 12-14, 2000 CL LAHAINA, HI SP AIAA, CEAS ID NOISE AB An aeroacoustic model test has been conducted to investigate the mechanisms of sound generation on high-lift wing configurations. This paper presents an analysis of flap side-edge noise, which is often the most dominant source. A model of a main element wing section with a half-span flap was tested at low speeds of up to a Mach number of 0.17, corresponding to a wing chord Reynolds number of approximately 1.7 million. Results are presented for flat (or blunt), flanged, and round flap-edge geometries, with and without boundary-layer tripping, deployed at both moderate and high flap angles. The acoustic database is obtained from a small aperture directional array (SADA) of microphones, which was constructed to electronically steer to different regions of the model and to obtain farfield noise spectra and directivity from these regions. The basic flap-edge aerodynamics is established by static surface pressure data, as well as by computational fluid dynamics (CFD) calculations and simplified edge flow analyses. Distributions of unsteady pressure sensors over the flap allow the noise source regions to be defined and quantified via cross-spectral diagnostics using the SADA output. It is found that shear layer instability and related pressure scatter is the primary noise mechanism. For the flat edge flap, two noise prediction methods based on unsteady-surface-pressure measurements are evaluated and compared to measured noise. One is a new causality spectral approach developed here. The other is a new application of an edge-noise scatter prediction method. The good comparisons for both approaches suggest that the prediction models capture much of the physics. Areas of disagreement appear to reveal when the assumed edge noise mechanism does not fully define the noise production. For the different edge conditions, extensive spectra and directivity are presented. The complexity of the directivity results demonstrate the strong role of edge source geometry and frequency in the noise radiation. Significantly, for each edge configuration, the spectra for different flow speeds, flap angles, and surface roughness were successfully scaled by utilizing aerodynamic performance and boundary-layer scaling methods developed herein. Published by Elsevier Science Ltd. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Brooks, TF (reprint author), NASA, Langley Res Ctr, Mail Stop 461, Hampton, VA 23681 USA. EM t.f.brooks@larc.nasa.gov NR 47 TC 28 Z9 29 U1 2 U2 8 PU ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-460X EI 1095-8568 J9 J SOUND VIB JI J. Sound Vibr. PD MAR 13 PY 2003 VL 261 IS 1 BP 31 EP 74 AR PII S0022-460X(02)00939-2 DI 10.1016/S0022-460X(02)00939-2 PG 44 WC Acoustics; Engineering, Mechanical; Mechanics SC Acoustics; Engineering; Mechanics GA 661CY UT WOS:000181874700003 ER PT J AU Koster, RD Suarez, MJ Higgins, RW Van den Dool, HM AF Koster, RD Suarez, MJ Higgins, RW Van den Dool, HM TI Observational evidence that soil moisture variations affect precipitation SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID PERSISTENCE AB [1] Land-atmosphere feedback, by which precipitation-induced soil moisture anomalies affect subsequent precipitation, may be an important element of Earth's climate system, but its very existence has never been demonstrated conclusively at regional to continental scales. Evidence for the feedback is sought in a 50-year observational precipitation dataset covering the United States. The precipitation variance and autocorrelation fields are characterized by features that agree (in structure, though not in magnitude) with those produced by an atmospheric general circulation model (AGCM). Because the model-generated features are known to result from land-atmosphere feedback alone, the observed features are suggestive of the existence of feedback in nature. C1 NASA, Hydrol Sci Branch, Lab Hydrospher Proc, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, Climate & Radiat Branch, Atmospheres Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NOAA, Climate Predict Ctr, NWS, NCEP, Washington, DC USA. RP NASA, Hydrol Sci Branch, Lab Hydrospher Proc, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM randal.d.koster@nasa.gov RI Koster, Randal/F-5881-2012 OI Koster, Randal/0000-0001-6418-6383 NR 14 TC 127 Z9 133 U1 3 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 MAR 12 PY 2003 VL 30 IS 5 AR 1241 DI 10.1029/2002GL016571 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 665ZN UT WOS:000182151300006 ER PT J AU Kamineni, R Krishnamurti, TN Ferrare, RA Ismail, S Browell, EV AF Kamineni, R Krishnamurti, TN Ferrare, RA Ismail, S Browell, EV TI Impact of high resolution water vapor cross-sectional data on hurricane forecasting SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB [1] This paper addresses the impact of moisture profile data sets derived from the Lidar Atmospheric Sensing Experiment (LASE) for the assimilation and forecasts of hurricanes. LASE is a vertical profiler for moisture measurements that was developed at NASA Langley Research Center. LASE was deployed on board the NASA DC-8 research aircraft and provided vertical profiles of moisture in a hurricane environment during the Convection and Moisture Experiment-4, which occurred in August and September 2001. In this preliminary study we show results from two types of experiments (with and without LASE data) that show improvements in track and intensity forecasts of hurricanes, Erin, Humberto and Gabrielle. When the LASE moisture profiles are assimilated, track errors are reduced by 100 km and intensity errors are reduced by 20-25% for 3 day forecasts. C1 Florida State Univ, Dept Meteorol, Tallahassee, FL 32306 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Kamineni, R (reprint author), Florida State Univ, Dept Meteorol, Tallahassee, FL 32306 USA. NR 9 TC 19 Z9 19 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAR 11 PY 2003 VL 30 IS 5 AR 1234 DI 10.1029/2002GL016741 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 665ZK UT WOS:000182151000010 ER PT J AU Vaughan, S Fabian, AC Nandra, K AF Vaughan, S Fabian, AC Nandra, K TI X-ray continuum variability of MCG-6-30-15 SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE galaxies : active; galaxies : individual : MCG-6-30-15; galaxies : Seyfert; X-rays : galaxies ID ACTIVE GALACTIC NUCLEI; TIMING-EXPLORER OBSERVATION; CYGNUS X-1; BLACK-HOLE; TIME-LAGS; SPECTRAL-ANALYSIS; POWER SPECTRUM; ACCRETION DISK; SPACED DATA; GX 339-4 AB This paper presents a comprehensive examination of the X-ray continuum variability of the bright Seyfert 1 galaxy MCG-6-30-15. The source clearly shows the strong, linear correlation between rms variability amplitude and flux first seen in Galactic X-ray binaries. The high-frequency power spectral density (PSD) of MCG-6-30-15 is examined in detail using a Monte Carlo fitting procedure and is found to be well represented by a steep power law at high frequencies (with a power-law index alpha approximate to 2.5), breaking to a flatter slope (alpha approximate to 1) below f(br) approximate to 0.6-2.0 x 10(-4) Hz, consistent with the previous results of Uttley, McHardy & Papadakis. The slope of the power spectrum above the break is energy dependent, with the higher energies showing a flatter PSD. At low frequencies the variations between different energy bands are highly coherent, while at high frequencies the coherence is significantly reduced. Time lags are detected between energy bands, with the soft variations leading the hard ones. The magnitude of the lag is small (less than or similar to200 s for the frequencies observed) and is most likely frequency dependent. These properties are remarkably similar to the temporal properties of the Galactic black hole candidate Cygnus X-1. The characteristic time-scales in these two types of source differ by similar to10(5); assuming that these time-scales scale linearly with black hole mass then suggests a black hole mass similar to10(6) M. for MCG-6-30-15. We speculate that the timing properties of MCG-6-30-15 may be analogous to those of Cyg X-1 in its high/soft state and discuss a simple phenomenological model, originally developed to explain the timing properties of Cyg X-1, which can explain many of the observed properties of MCG-6-30-15. C1 Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England. EM sav@ast.cam.ac.uk NR 78 TC 119 Z9 120 U1 0 U2 0 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 MAR 11 PY 2003 VL 339 IS 4 BP 1237 EP 1255 DI 10.1046/j.1365-8711.2003.06285.x PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 650VD UT WOS:000181283300032 ER PT J AU Bonamente, M Joy, MK Lieu, R AF Bonamente, M Joy, MK Lieu, R TI A massive warm baryonic halo in the Coma Cluster SO ASTROPHYSICAL JOURNAL LA English DT Article DE large-scale structure of universe; X-rays : galaxies : clusters; X-rays : individual (Coma cluster) ID EXTREME-ULTRAVIOLET EMISSION; HOT INTERGALACTIC MEDIUM; GALAXY CLUSTERS; INTERSTELLAR-MEDIUM; CROSS-SECTIONS; DIFFUSE; ABSORPTION; TELESCOPE; ELECTRONS; RADIATION AB Several deep PSPC observations of the Coma Cluster reveal a very large scale halo of soft X-ray emission, substantially in excess of the well-known radiation from the hot intracluster medium. The excess emission, previously reported in the central region of the cluster using lower sensitivity Extreme Ultraviolet Explorer (EUVE) and ROSAT data, is now evident out to a radius of 2.6 Mpc, demonstrating that the soft excess radiation from clusters is a phenomenon of cosmological significance. The X-ray spectrum at these large radii cannot be modeled nonthermally but is consistent with the original scenario of thermal emission from warm gas at similar to10(6) K. The mass of the warm gas is on par with that of the hot X-ray emitting plasma and significantly more massive if the warm gas resides in low-density lamentary structures. Thus, the data lend vital support to current theories of cosmic evolution, which predict that at low redshift similar to30%-40% of the baryons reside in warm laments converging at clusters of galaxies. C1 Univ Alabama, Dept Phys, Huntsville, AL 35899 USA. NASA, Natl Space Sci & Technol Ctr, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Bonamente, M (reprint author), Univ Alabama, Dept Phys, Huntsville, AL 35899 USA. NR 42 TC 27 Z9 27 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 MAR 10 PY 2003 VL 585 IS 2 BP 722 EP 729 DI 10.1086/346220 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 650WU UT WOS:000181287200013 ER PT J AU Tran, HD Sirianni, M Ford, HC Illingworth, GD Clampin, M Hartig, G Becker, RH White, RL Bartko, F Benitez, N Blakeslee, JP Bouwens, R Broadhurst, TJ Brown, R Burrows, C Cheng, E Cross, N Feldman, PD Franx, M Golimowski, DA Gronwall, C Infante, L Kimble, RA Krist, J Lesser, M Magee, D Martel, AR McCann, WJ Meurer, GR Miley, G Postman, M Rosati, P Sparks, WB Tsvetanov, Z AF Tran, HD Sirianni, M Ford, HC Illingworth, GD Clampin, M Hartig, G Becker, RH White, RL Bartko, F Benitez, N Blakeslee, JP Bouwens, R Broadhurst, TJ Brown, R Burrows, C Cheng, E Cross, N Feldman, PD Franx, M Golimowski, DA Gronwall, C Infante, L Kimble, RA Krist, J Lesser, M Magee, D Martel, AR McCann, WJ Meurer, GR Miley, G Postman, M Rosati, P Sparks, WB Tsvetanov, Z TI Advanced camera for surveys observations of young star clusters in the interacting galaxy UGC 10214 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : individual (Arp 188, UGC 10214, VV 29); galaxies : star clusters ID HUBBLE-SPACE-TELESCOPE; ANTENNAE GALAXIES; POPULATION; IMAGES AB We present the first Advanced Camera for Surveys (ACS) observations of young star clusters in the colliding/merging galaxy UGC 10214. The observations were made as part of the Early Release Observation (ERO) program for the newly installed ACS during service mission SM3B for the Hubble Space Telescope (HST). Many young star clusters can be identified in the tails of UGC 10214, with ages ranging from similar to3 to 10 Myr. The extreme blue V-I (F606W-F814W) colors of the star clusters found in the tail of UGC 10214 can only be explained if strong emission lines are included with a young stellar population. This has been confirmed by our Keck spectroscopy of some of these bright blue stellar knots. The most luminous and largest of these blue knots has an absolute magnitude of M-V = 14.45, with a half-light radius of 161 pc, and if it is a single star cluster, it would qualify as a super star cluster (SSC). Alternatively, it could be a superposition of multiple scaled OB associations or clusters. With an estimated age of similar to4-5 Myr, its derived mass is less than 1.3 x 10(6) M-.. Thus, the young stellar knot is unbound and will not evolve into a normal globular cluster. The bright blue clusters and associations are much younger than the dynamical age of the tail, providing strong evidence that star formation occurs in the tail long after it was ejected. UGC 10214 provides a nearby example of processes that contributed to the formation of halos and intracluster media in the distant and younger universe. C1 Johns Hopkins Univ, Dept Phys & Astron, Bloomberg Ctr, 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. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94550 USA. Bartko Sci & Technol, Mead, CO 80542 USA. Hebrew Univ Jerusalem, Racah Inst Phys, IL-91904 Jerusalem, Israel. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Leiden Observ, NL-2300 Leiden, Netherlands. Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA. Pontificia Univ Catolica Chile, Santiago 22, Chile. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. European So Observ, D-85748 Garching, Germany. RP Tran, HD (reprint author), Johns Hopkins Univ, Dept Phys & Astron, Bloomberg Ctr, Charles & 34th 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 31 TC 50 Z9 50 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 MAR 10 PY 2003 VL 585 IS 2 BP 750 EP 755 DI 10.1086/346125 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 650WU UT WOS:000181287200016 ER PT J AU Martinez-Galarce, DS Walker, ABC Barbee, TW Hoover, RB AF Martinez-Galarce, DS Walker, ABC Barbee, TW Hoover, RB TI The solar chromosphere/corona interface. I. Far-ultraviolet to extreme-ultraviolet observations and modeling of unresolved coronal funnels SO ASTROPHYSICAL JOURNAL LA English DT Article DE instrumentation : spectrographs; Sun : chromosphere; Sun : corona; Sun : transition region; Sun : UV radiation; Sun : X-rays; gamma rays ID HIGH-RESOLUTION TELESCOPE; TRANSITION REGION; ENERGY-BALANCE; POLAR PLUMES; MAGNETIC-STRUCTURE; ATOMIC DATABASE; EMISSION-LINES; QUIET SUN; NETWORK; ATMOSPHERE AB A coronal funnel model, developed by D. Rabin, was tested against a calibrated spectroheliogram recorded in the 170-175 Angstrom bandpass. This image was recorded on board a sounding-rocket experiment own on 1994 November 3, called the Multi-Spectral Solar Telescope Array II (MSSTA II). MSSTA, a joint project of Stanford University, the NASA Marshall Space Flight Center, and the Lawrence Livermore National Laboratory, is an observing platform composed of a set of normal-incidence, multilayer-coated optics designed to obtain narrow-bandpass, high-resolution images (1"-3") at selected far-ultraviolet (FUV), extreme-ultraviolet (EUV), and soft X-ray wavelengths (44-1550 Angstrom). Using full-disk images centered at 1550 Angstrom (C IV) and 173 Angstrom (Fe IX/X, the funnel model, which is based on coronal back-heating, was tested against the data incorporating observed constraints on global coverage and measured flux. Found was a class of funnel models that could account for the quiescent, globally diffuse and unresolved emission seen in the 171-175 Angstrom bandpass, where the funnels are assumed to be rooted in the C IV supergranular network. These models, when incorporated with the CHIANTI spectral code, suggest that this emission is mostly of upper transition region origin and primarily composed of Fe IX plasma. The funnels are found to have constrictions, Gamma similar to 6-20, which is in good agreement with the observations. Further, the fitted models simultaneously satisfy global areal constraints seen in both images; namely, that a global network of funnels must cover similar to70%-95% of the total solar surface area seen in the 171-175 Angstrom image, and less than or equal to45% of the disk area seen in the 1550 Angstrom bandpass. These findings support the configuration of the EUV magnetic network as suggested by Reeves et al. and put forth in more detail by Gabriel. Furthermore, the models are in good agreement with differential emission measure estimates made of the transition region by J. C. Raymond & J. G. Doyle for temperatures 250,000 K less than or equal to T less than or equal to 650,000 K, based on full-disk observations made on board Skylab. C1 Lockheed Martin Solar & Astrophys Lab, Palo Alto, CA 94304 USA. Stanford Univ, Dept Phys, Stanford, CA 94305 USA. Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NASA, George C Marshall Space Flight Ctr, Space Sci Lab, Huntsville, AL 35812 USA. Stanford Univ, Dept Appl Phys, Stanford, CA 94305 USA. RP Lockheed Martin Solar & Astrophys Lab, 3251 Hanover St,O-L9-41,B-252, Palo Alto, CA 94304 USA. EM denmart@lmsal.com; walker@banneker.stanford.edu; barbee2@llnl.gov; hoover@ssl.msfc.nasa.gov NR 62 TC 3 Z9 3 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 MAR 10 PY 2003 VL 585 IS 2 BP 1095 EP 1113 PN 1 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 650WU UT WOS:000181287200046 ER PT J AU Burlaga, LF Wang, C Richardson, JD Ness, NF AF Burlaga, LF Wang, C Richardson, JD Ness, NF TI Large-scale magnetic field fluctuations and development of the 1999-2000 global merged interaction region: 1-60 Au SO ASTROPHYSICAL JOURNAL LA English DT Article DE magnetic fields; solar wind ID COSMIC-RAY MODULATION; SOLAR-WIND; VOYAGER-2 OBSERVATIONS; MULTIFRACTAL STRUCTURE; OUTER HELIOSPHERE; DISTRIBUTIONS; TURBULENCE; EVOLUTION; SHOCK; 1-AU AB We use a multifluid, spherically symmetric, MHD model with neutral atoms and pickup protons, with 1999 solar wind data at 1 AU as input, to calculate the magnetic field strength (B) profiles that would be observed at various points between 1 and 60 AU with a resolution of 1 day over an interval of similar to1 yr. These temporal profiles show radial evolution of the multiscale fluctuations in B near solar maximum. From the daily points in these profiles, one finds the following statistical results for the radial evolution of daily averages of B : (1) the distribution functions of B are approximately lognormal at all distances from 1 to 60 AU; (2) the standard deviation of B divided by the mean value of B, [B], for the magnetic field pro le at a given distance is approximately a constant, independent of distance between 10 and 60 AU; and (3) the power spectrum of B/[B] evolves such that (a) at small scales the power spectral density decreases with increasing distance from the Sun, (b) at large scales the power spectral density increases with distance, and (c) there is a range of frequencies in which the power spectrum is a power law, the power law extending to ever lower frequencies with increasing distance. All three of these results have been observed by the Voyager 1 and 2 spacecraft over the last 25 yr, between 1 and similar to60 AU. The radial evolution of the multiscale changes in B/[B] is described by analyzing the normalized changes in B at different scales, dB(n). The multiscale structure of the probability distributions of dB(n) changes qualitatively with increasing distance from the Sun. The standard deviation surface, SDn(n, R), shows (1) a ridge at 5 AU (which is a function of scale n), corresponding to the development of shocks and interaction regions at large and intermediate scales; (2) a second ridge at a scale of 64 days (which is a function of R), corresponding to the formation, growth, and initial decay of a large-scale, global merged interaction region; and (3) a valley corresponding to the decrease in the amplitude of the fluctuations in B/[B] over an increasing range of scales with increasing distance from the Sun. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. MIT, Ctr Space Res, Cambridge, MA 02139 USA. Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA. Chinese Acad Sci, Lab Space Weather, Beijing, Peoples R China. RP Burlaga, LF (reprint author), NASA, Goddard Space Flight Ctr, Code 692, Greenbelt, MD 20771 USA. NR 30 TC 23 Z9 23 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 10 PY 2003 VL 585 IS 2 BP 1158 EP 1168 DI 10.1086/346108 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 650WU UT WOS:000181287200051 ER PT J AU Gehrels, N Laird, CM Jackman, CH Cannizzo, JK Mattson, BJ Chen, W AF Gehrels, N Laird, CM Jackman, CH Cannizzo, JK Mattson, BJ Chen, W TI Ozone depletion from nearby supernovae SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic rays; Earth; molecular processes; supernovae : general; supernovae : individual (SN 1987A) ID GALACTIC COSMIC-RAYS; SOLAR PROTON EVENTS; 2-DIMENSIONAL MODEL; STRATOSPHERIC AIRCRAFT; MIDDLE ATMOSPHERE; EXPLOSIONS; NITROGEN; EXTINCTION; TRACERS; STARS AB Estimates made in the 1970s indicated that a supernova occurring within tens of parsecs of Earth could have significant effects on the ozone layer. Since that time, improved tools for detailed modeling of atmospheric chemistry have been developed to calculate ozone depletion, and advances have been made also in theoretical modeling of supernovae and of the resultant gamma-ray spectra. In addition, we now have better knowledge of the occurrence rate of supernovae in the Galaxy and of the spatial distribution of progenitors to core-collapse supernovae. We report here the results of two-dimensional atmospheric model calculations that take as input the spectral energy distribution of a supernova, adopting various distances from Earth and various latitude impact angles. In separate simulations we calculate the ozone depletion due to both gamma rays and cosmic rays. We find that for the combined ozone depletion from these effects roughly to double the "biologically active" UV flux received at the surface of the Earth, the supernova must occur at less than or similar to8 pc. Based on the latest data, the time-averaged Galactic rate of core-collapse supernovae occurring within 8 pc is similar to1.5 Gyr(-1). In comparing our calculated ozone depletions with those of previous studies, we find them to be significantly less severe than found by Ruderman and consistent with Whitten et al. In summary, given the amplitude of the effect, the rate of nearby supernovae, and the similar to0.5 Gyr timescale for multicellular organisms on Earth, this particular pathway for mass extinctions may be less important than previously thought. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Sprint IP Design, Reston, VA 20196 USA. Haskel Indian Nations Univ, Lawrence, KS 66046 USA. Univ Maryland Baltimore Cty, Baltimore, MD 21228 USA. RP Gehrels, N (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Code 661, Greenbelt, MD 20771 USA. RI Gehrels, Neil/D-2971-2012; Jackman, Charles/D-4699-2012 NR 38 TC 66 Z9 67 U1 0 U2 6 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 10 PY 2003 VL 585 IS 2 BP 1169 EP 1176 DI 10.1086/346127 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 650WU UT WOS:000181287200052 ER PT J AU Temi, P Mathews, WG Brighenti, F Bregman, JD AF Temi, P Mathews, WG Brighenti, F Bregman, JD TI Dust in hot gas: Far-infrared emission from three local elliptical galaxies SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : elliptical and lenticular, cD galaxies : individual (NGC 4472, NGC 4636, NGC 4649); galaxies : ISM; infrared : galaxies; infrared : ISM ID INTERSTELLAR GRAINS AB We present far-IR Infrared Space Observatory observations of three early-type galaxies in the Virgo Cluster. The data were recorded using the ISOPHOT instrument in both the P32 oversampled maps and the P39/37 sparse maps. The maps reach the limiting sensitivity of the ISOPHOT instrument at 60, 90, and 180 m m. Two of the most prominent elliptical galaxies in Virgo-NGC 4472 and NGC 4649-clearly show no emission at far-IR wavelengths at a level of a few tens of millijanskys, but NGC 4636 is detected at all three wavelengths. We have computed the far-IR emission from dust for NGC 4472 and NGC 4636 under the assumption that dusty outflows from evolving red giant stars are continuously supplying dust to the interstellar medium and that the grains, once diffused into the interstellar medium, are sputtered away by collisions with ions. While the calculated fluxes are consistent with the observed upper limits for NGC 4472, the dust emission detected in NGC 4636 supports the hypothesis that additional dust has been accreted in a very recent (approximately less than a few times 10(8) yr) merger with a dusty, gas-rich galaxy. C1 NASA, Astrophys Branch, Ames Res Ctr, Moffett Field, CA 94035 USA. SETI Inst, Mountain View, CA 94043 USA. Univ Calif Santa Cruz, Univ Calif Observ, Lick Observ, Board Studies Astron & Astrophys, Santa Cruz, CA 95064 USA. Univ Bologna, Dipartimento Astron, I-40127 Bologna, Italy. RP Temi, P (reprint author), NASA, Astrophys Branch, Ames Res Ctr, MS 245-6, Moffett Field, CA 94035 USA. NR 23 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 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 10 PY 2003 VL 585 IS 2 BP L121 EP L124 DI 10.1086/374326 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 650WV UT WOS:000181287300012 ER PT J AU Yang, Y Mushotzky, RF Barger, AJ Cowie, LL Sanders, DB Steffen, AT AF Yang, Y Mushotzky, RF Barger, AJ Cowie, LL Sanders, DB Steffen, AT TI Imaging large-scale structure in the X-ray sky SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : observations; galaxies : nuclei; large-scale structure of universe; X-rays : diffuse background ID ANGULAR-CORRELATION; GALAXY; UNIVERSE; ASCA AB We present the first results from a wide solid angle, moderately deep Chandra survey of the Lockman Hole North-West region. Our nine ACIS-I fields cover an effective solid angle of 0.4 deg(2) and reach a depth of 3 x 10(-16) ergs cm(-2) s(-1) in the 0.4-2 keV band and 3 x 10(-15) ergs cm(-2) s(-1) in the 2-8 keV band. The best-fit log N-log S for the entire field matches well onto that of the Chandra Deep Field-North. We show that the full range of the "cosmic variance" previously seen in different Chandra fields is reproduced in this small region of the sky. A counts-in-cells analysis shows that the hard-band sources are more strongly correlated than the soft-band sources. C1 Univ Maryland, Dept Astron, College Pk, MD 20742 USA. NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20770 USA. Univ Wisconsin, Dept Astron, Madison, WI 53760 USA. Univ Hawaii, Dept Phys & Astron, Honolulu, HI 96822 USA. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. Max Planck Inst Extraterr Phys, D-85740 Garching, Germany. RP Yang, Y (reprint author), Univ Maryland, Dept Astron, College Pk, MD 20742 USA. NR 30 TC 60 Z9 60 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 MAR 10 PY 2003 VL 585 IS 2 BP L85 EP L88 DI 10.1086/374372 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 650WV UT WOS:000181287300003 ER PT J AU Covault, C AF Covault, C TI Shuffle probe intensifies SO AVIATION WEEK & SPACE TECHNOLOGY LA English DT Article C1 Lyndon B Johnson Space Ctr, Houston, TX USA. RP Covault, C (reprint author), Lyndon B Johnson Space Ctr, Houston, TX USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MCGRAW HILL INC PI NEW YORK PA 1221 AVENUE OF THE AMERICAS, NEW YORK, NY 10020 USA SN 0005-2175 J9 AVIAT WEEK SPACE TEC JI Aviat. Week Space Technol. PD MAR 10 PY 2003 VL 158 IS 10 BP 26 EP + PG 3 WC Engineering, Aerospace SC Engineering GA 653YY UT WOS:000181465700021 ER PT J AU Wu, SY Liu, AK AF Wu, SY Liu, AK TI Towards an automated ocean feature detection, extraction and classification scheme for SAR imagery SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID SYNTHETIC-APERTURE RADAR; ICE-SHEET; INTERFEROMETRY AB Spaceborne synthetic aperture radar (SAR) observation is all important tool for monitoring and studying changes in various geophysical elements in and above world oceans. Because of SAR's ideal imaging capability and high resolution, the collection of SAR data will likely extend well into the 21st century. As the data become increasingly abundant and computers faster and more affordable, it naturally leads to an increasing need for an automated procedure to replace the labour-intensive manual screening process. In this paper an integrated scheme for detection extraction and classification of linear ocean features in SAR imagery is attempted for the Purpose Of automated screening. The methodology consists of feature detection based on greyscale histogram screening, feature extraction based on two-dimensional wavelet analysis and feature classification based on texture analysis. Using these algorithms on SAR data several case studies of linear ocean features including fronts, ice edges and a polar low are presented herein, Though not fully automated at this stage, the integration of these algorithms seems to lay a promising foundation for the future development of a more automated ocean feature detection, extraction and classification scheme. C1 NASA, Goddard Space Flight Ctr, Oceans & Ice Branch, Greenbelt, MD 20771 USA. RP Wu, SY (reprint author), NASA, Goddard Space Flight Ctr, Oceans & Ice Branch, Code 661, Greenbelt, MD 20771 USA. NR 22 TC 39 Z9 41 U1 1 U2 3 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 MAR 10 PY 2003 VL 24 IS 5 BP 935 EP 951 DI 10.1080/01431160210144606 PG 17 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 662BT UT WOS:000181926400003 ER PT J AU Conkright, ME Gregg, WW AF Conkright, ME Gregg, WW TI Comparison of global chlorophyll climatologies: In situ, CZCS, Blended in situ-CZCS and SeaWiFS SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID ANTARCTIC PENINSULA WATERS; OCEANIC PRIMARY PRODUCTION; NORTH PACIFIC-OCEAN; PHYTOPLANKTON PIGMENT; BIOOPTICAL PROPERTIES; SOUTHERN-OCEAN; SATELLITE CHLOROPHYLL; DATA-SET; EL-NINO; COLOR AB Chlorophyll climatologies derived from historical in situ data, Coastal Zone Color Scanner data (CZCS) and SeaWiFS (Version 3) data were intercompared to evaluate their strengths and weaknesses in representing chlorophyll distributions in the global ocean. A fourth dataset, produced by blending ill situ data with CZCS data was compared to the other three. Systematic biases were associated with each of these datasets. In situ and CZCS data appeared to underestimate chlorophyll since the blended analysis produced generally elevated values. The underestimate by situ data is related to problems mostly in the analysis of the data. CZCS underestimates are related to calibration and algorithm problems. The SeaWiFS data for the open ocean appears to be valid since its within 10% of the blended climatology for all seasons except winter. In the coastal ocean, SeaWiFS may overestimate chlorophyll with values 30-77% higher than the next closest climatology. Blending of in situ and satellite may produce the best climatology. This method takes advantage of the higher quality of in situ data. and the spatial variability of satellite sensor data, The blended method may be of greatest use for SeaWiFS in coastal areas. where the algorithm problems are greatest. C1 NOAA, Ocean Climate Lab, Natl Oceanog Data Ctr, Silver Spring, MD 20910 USA. NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. RP Conkright, ME (reprint author), NOAA, Ocean Climate Lab, Natl Oceanog Data Ctr, E-OC5, Silver Spring, MD 20910 USA. NR 62 TC 19 Z9 21 U1 1 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 MAR 10 PY 2003 VL 24 IS 5 BP 969 EP 991 DI 10.1080/01431160110115573 PG 23 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 662BT UT WOS:000181926400005 ER PT J AU Banger, KK Duraj, SA Fanwick, PE Hepp, AF Martuch, RA AF Banger, KK Duraj, SA Fanwick, PE Hepp, AF Martuch, RA TI Synthesis, and structural characterization of [{CH3(C5H4N)}Ga(SCH2(CO)O)(2)](-)[(4-mepyH)](+), a novel Ga(III) five-coordinate complex SO JOURNAL OF COORDINATION CHEMISTRY LA English DT Article ID GALLIUM SULFIDE; PRECURSORS AB The synthesis and structural characterization of a novel ionic Ga(III) five-coordinate complex [{CH3(C5H4N))Ga(SCH2(CO)O)(2)](-)[(4-MepyH)](+), (4-Mepy=CH3(C5H5N)) from the reaction between Ga2Cl4 with sodium mercapto-acetic acid in 4-methylpyridine is described. Under basic reaction conditions the mercapto ligand is found to behave as a 2e(-) bidentate ligand. Single crystal X-ray diffraction studies show the complex to have a distorted square-pyramidal geometry with the [(-SCH2(CO)CO-)] ligands trans. The compound crystallizes in the P2(1)/c (No. 14) space group with a = 7.7413(6) Angstrom, b = 16.744(2) Angstrom, c = 14.459(2) Angstrom, V= 1987.1(6) Angstrom(3), R(F-o)=0.032 and R-w=0.038. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Ohio Aerosp Inst, Cleveland, OH 44142 USA. Cleveland State Univ, Dept Chem, Cleveland, OH 44115 USA. Purdue Univ, Dept Chem, W Lafayette, IN 47907 USA. RP Banger, KK (reprint author), NASA, Glenn Res Ctr, MS 302-1,21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 20 TC 1 Z9 1 U1 0 U2 0 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 MAR 10 PY 2003 VL 56 IS 4 BP 307 EP 312 DI 10.1080/0095897031000069067 PG 6 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 676UA UT WOS:000182769700007 ER PT J AU Hobbs, PV Sinha, P Yokelson, RJ Christian, TJ Blake, DR Gao, S Kirchstetter, TW Novakov, T Pilewskie, P AF Hobbs, PV Sinha, P Yokelson, RJ Christian, TJ Blake, DR Gao, S Kirchstetter, TW Novakov, T Pilewskie, P TI Evolution of gases and particles from a savanna fire in South Africa SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE gases; particles; biomass fires; smoke; savanna fires; evolution of smoke ID BIOMASS BURNING PLUMES; ATMOSPHERIC CHEMISTRY; TROPOSPHERIC OZONE; ORGANIC-COMPOUNDS; FOREST FIRES; TRACE GASES; EMISSIONS; CARBON; ATLANTIC; NITROGEN AB [1] Airborne measurements of particles and gases from a 1000- ha savanna fire in South Africa are presented. These measurements represent the most extensive data set reported on the aging of biomass smoke. The measurements include total concentrations of particles ( CN), particle sizes, particulate organic carbon and black carbon, light- scattering coefficients, downwelling UV fluxes, and mixing ratios for 42 trace gases and 7 particulate species. The ratios of excess nitrate, ozone, and gaseous acetic acid to excess CO increased significantly as the smoke aged over similar to 40 - 45 min, indicating that these species were formed by photochemistry in the plume. For 17 other species, the excess mixing ratio normalized by the excess mixing ratio of CO decreased significantly with smoke age. The relative rates of decrease for a number of chemical species imply that the average OH concentration in the plume was similar to 1.7 x 10(7) molecules cm(-3). Excess CN, normalized by excess CO, decreased rapidly during the first similar to 5 min of aging, probably due to coagulation, and then increased, probably due to gas- to- particle conversion. The CO- normalized concentrations of particles < 1.5 mu m in diameter decreased, and particles > 1.5 mum diameter increased, with smoke age. The spectral depletion of solar radiation by the smoke is depicted. The downwelling UV flux near the vertical center of the plume was about two- thirds of that near the top of the plume. C1 Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. Univ Montana, Dept Chem, Missoula, MT 59812 USA. Univ Calif Irvine, Dept Chem, Irvine, CA 92717 USA. Univ Washington, Dept Chem, Seattle, WA 98195 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Hobbs, PV (reprint author), Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. EM phobbs@atmos.washington.edu RI Yokelson, Robert/C-9971-2011 OI Yokelson, Robert/0000-0002-8415-6808 NR 48 TC 119 Z9 120 U1 3 U2 19 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 MAR 8 PY 2003 VL 108 IS D13 AR 8485 DI 10.1029/2002JD002352 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 665VK UT WOS:000182141800004 ER PT J AU Hall, TM Holzer, M AF Hall, TM Holzer, M TI Advective-diffusive mass flux and implications for stratosphere-troposphere exchange SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID TRANSPORT; TROPOPAUSE; AGE; TIME; EDGE AB [1] We show that the flux of mass crossing in one direction (the "gross'' flux) through any specified surface S that divides anadvective-diffusive flow in a closed domain is infinite. That is, the flux, F (tau), through S of the fluid mass that spent at least time tau on one side of S diverges like tau(-1/2) as tau --> 0, in the continuum limit. The gross flux is completely dominated by fluid elements residing infinitesimally short times on one side of S before re-crossing to the other side. This general result puts into context the widely varying estimates of gross mass flux across the midlatitude tropopause. Such estimates are dominated by the smallest resolved scales, leading us to conclude that gross mass flux is not a useful diagnostic of stratosphere-troposphere exchange. The function F (tau), however, provides important information on transport across the tropopause. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Columbia Univ, New York, NY USA. Univ British Columbia, Dept Earth & Ocean Sci, Vancouver, BC V6T 1Z4, Canada. Langara Coll, Dept Phys, Vancouver, BC, Canada. RP Hall, TM (reprint author), NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. EM thall@giss.nasa.gov; mholzer@eos.ubc.ca NR 18 TC 26 Z9 26 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 MAR 7 PY 2003 VL 30 IS 5 AR 1222 DI 10.1029/2002GL016419 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 665FJ UT WOS:000182108700005 ER PT J AU Hsu, NC Herman, JR Tsay, SC AF Hsu, NC Herman, JR Tsay, SC TI Radiative impacts from biomass burning in the presence of clouds during boreal spring in southeast Asia SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article DE biomass burning; aerosols; clouds; radiative forcing; southeast Asia; monsoon ID AEROSOLS; SMOKE; SYSTEM; TOMS AB [1] The impact of smoke aerosols generated from biomass burning activities in Southeast Asia on the total (i.e., direct and indirect effects) reflected solar and emitted thermal radiation from clouds was investigated using satellite data. We combine narrowband radiance measurements, from ultraviolet to near-infrared wavelengths (e.g., SeaWiFS and TOMS), with broadband irradiance measurements (e. g., CERES) to quantify how smoke aerosols modulate the cloud radiative forcing. In Southeast Asia, our results reveal that smoke is frequently present over large areas of cloud-covered regions during boreal spring. The reflected solar (emitted thermal) radiation from clouds due to smoke aerosols can be reduced (enhanced) by as much as 100 (20) W m(-2) over the month of March 2000. We also found that the reduction in cloud spectral reflectance at 670 nm is large enough to lead to significant errors in retrieving cloud properties (e. g., optical thickness and effective radius) from current satellite measurements, such as AVHRR and MODIS. C1 Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21250 USA. NASA, Atmospheres Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Hsu, NC (reprint author), Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, 1000 Hilltop Circle, Baltimore, MD 21250 USA. RI Hsu, N. Christina/H-3420-2013; Tsay, Si-Chee/J-1147-2014 NR 14 TC 53 Z9 53 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 MAR 7 PY 2003 VL 30 IS 5 AR 1224 DI 10.1029/2002GL016485 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 665FJ UT WOS:000182108700007 ER PT J AU Porco, CC West, RA McEwen, A Del Genio, AD Ingersoll, AP Thomas, P Squyres, S Dones, L Murray, CD Johnson, TV Burns, JA Brahic, A Neukum, G Veverka, J Barbara, JM Denk, T Evans, M Ferrier, JJ Geissler, P Helfenstein, P Roatsch, T Throop, H Tiscareno, M Vasavada, AR AF Porco, CC West, RA McEwen, A Del Genio, AD Ingersoll, AP Thomas, P Squyres, S Dones, L Murray, CD Johnson, TV Burns, JA Brahic, A Neukum, G Veverka, J Barbara, JM Denk, T Evans, M Ferrier, JJ Geissler, P Helfenstein, P Roatsch, T Throop, H Tiscareno, M Vasavada, AR TI Cassini imaging of Jupiter's atmosphere, satellites, and rings SO SCIENCE LA English DT Article ID GREAT RED SPOT; MOIST CONVECTION; CLOUD STRUCTURE; EQUATORIAL REGION; GIANT PLANETS; ZONAL WINDS; SYSTEM; IMAGES; IO; ULTRAVIOLET AB The Cassini Imaging Science Subsystem acquired about 26,000 images of the Jupiter system as the spacecraft encountered the giant planet en route to Saturn. We report findings on Jupiter's zonal winds, convective storms, low-latitude upper troposphere, polar stratosphere, and northern aurora. We also describe previously unseen emissions arising from lo and Europa in eclipse, a giant volcanic plume over lo's north pole, disk-resolved images of the satellite Himalia, circumstantial evidence for a causal relation between the satellites Metis and Adrastea and the main jovian ring, and information on the nature of the ring particles. C1 SW Res Inst, Dept Space Sci, Boulder, CO 80302 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Arizona, Dept Planetary Sci, Tucson, AZ 85721 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. Univ London, Queen Mary, Astron Unit, London E1 4NS, England. Univ Paris, Ctr Etud Saclay, F-91191 Gif Sur Yvette, France. Free Univ Berlin, Dept Earth Sci, D-12249 Berlin, Germany. German Aerosp Ctr, Inst Space Sensor Technol & Planetary Explorat, D-12489 Berlin, Germany. Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90095 USA. RP Porco, CC (reprint author), SW Res Inst, Dept Space Sci, 1050 Walnut St,Suite 400, Boulder, CO 80302 USA. RI Tiscareno, Matthew/D-6963-2011; Del Genio, Anthony/D-4663-2012 OI Del Genio, Anthony/0000-0001-7450-1359 NR 60 TC 215 Z9 215 U1 2 U2 13 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 MAR 7 PY 2003 VL 299 IS 5612 BP 1541 EP 1547 DI 10.1126/science.1079462 PG 7 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 652EY UT WOS:000181367900028 PM 12624258 ER PT J AU Eymard, L Weill, A Bourras, D Guerin, C Le Borgne, P Lefevre, JM AF Eymard, L Weill, A Bourras, D Guerin, C Le Borgne, P Lefevre, JM TI Use of ship mean data for validating model and satellite flux fields during the FETCH experiment SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article DE surface fluxes; ship; model; satellite; validation; FETCH experiment ID LATENT-HEAT FLUX; SURFACE-LAYER TURBULENCE; SEA-SURFACE; TOGA COARE; NORTH-ATLANTIC; SPECTRAL CHARACTERISTICS; SENSIBLE HEAT; WATER-VAPOR; OCEAN; EVAPORATION AB During the FETCH experiment in NW Mediterranean Sea (March and April 1998), surface fluxes were measured on board a research vessel and on a moored buoy. To provide the ocean surface forcing at the mesoscale, output fields of three meteorological models (European Centre for Medium-Range Weather Forecasts (ECMWF) and Meteo-France ARPEGE and ALADIN) were gathered as well as satellite data. To evaluate the consistency of model fields, we compare ship measurements to the predicted radiative and turbulent surface fluxes and to turbulent fluxes derived from analyses using a bulk formula. We first analyze the quality of the ship bulk fluxes in terms of possible effects of the flow distortion and of intrinsic variability as function of the integration time. The airflow distortion over the ship is found to significantly affect fluxes, but the mean fluxes over the experiment remain unchanged because of compensation between positive and negative errors due to the varying apparent wind direction. Spectral analysis of the ship time series as well as comparison of fluxes obtained by using several averaging times from 1 to 90 min show that the optimal scale for computing ship fluxes is about 20 min, ensuring consistency with the derivation of bulk drag and exchange coefficient. These fluxes are then taken as reference for the comparison with models and satellites. None of the predicted radiative fluxes is consistent with ship measurements. Model turbulent fluxes differ from each other, and the main reason is the discrepancy between modeled and observed atmospheric features. Large discrepancies are found between predicted fluxes and ship fluxes in strong wind conditions due to the different flux parameterization for heat fluxes. Model bulk fluxes thus compare better to ship than predicted fluxes, particularly during the middle period of the experiment. On the contrary, the Meteosat-derived downward radiative fluxes are comparable to the ship data, and their high time sampling allows us to describe the diurnal cycle of the solar heating. They can be used either at an instantaneous scale (comparison of the satellite flux averaged over 0.1degrees x 0.1degrees with 10 min averaged ship fluxes) or at a larger scale (0.3degrees x 0.3degrees,1 hour). It is shown that the surface latent heat flux, derived from a combination of Special Sensor Microwave Imager (SSMI) brightness temperatures and sea surface temperature (SST), as obtained from IR sensors (Advanced Very High Resolution Radiometer (AVHRR), is of a quality similar or better to model bulk fluxes. C1 CNRS, CETP IPSL, F-78140 Velizy Villacoublay, France. Jet Propuls Lab, Pasadena, CA USA. CMS, Lannion, France. SCEM, Toulouse, France. RP Eymard, L (reprint author), CNRS, CETP IPSL, 10-12 Ave Europe, F-78140 Velizy Villacoublay, France. NR 61 TC 9 Z9 9 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-OCEANS JI J. Geophys. Res.-Oceans PD MAR 6 PY 2003 VL 108 IS C3 AR 8060 DI 10.1029/2001JC001207 PG 20 WC Oceanography SC Oceanography GA 665WR UT WOS:000182144700004 ER PT J AU Song, KD Yi, WJ Chu, SH Choi, SH AF Song, KD Yi, WJ Chu, SH Choi, SH TI Microwave-driven thunder materials SO MICROWAVE AND OPTICAL TECHNOLOGY LETTERS LA English DT Article DE microwave control; smart materials; THUNDER; rectenna; PAD AB An experimental study of a smart-materials actuator driven by a microwave is presented in this paper. A proof-of-concept experiment using a smart material, much as thin layer composite unimorph ferroelectric driver and sensor (THUNDER), has been demonstrated with wirelessly transmitted microwave power. Such an advance system will offer a new class of smart devices that are remotely controlled via wirelessly transmitted power. Thus, a system of this nature autonomously functions without an onboard power infrastructure. Potential applications are integrated sensors. actuators, and smart flight control in space applications, as Well as biologically-inspired systems. (C) 2003 Wiley Periodicals, Inc. C1 Norfolk State Univ, Dept Engn, Norfolk, VA 23504 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Song, KD (reprint author), Norfolk State Univ, Dept Engn, Norfolk, VA 23504 USA. NR 14 TC 15 Z9 15 U1 0 U2 3 PU JOHN WILEY & SONS INC PI HOBOKEN PA 111 RIVER ST, HOBOKEN, NJ 07030 USA SN 0895-2477 J9 MICROW OPT TECHN LET JI Microw. Opt. Technol. Lett. PD MAR 5 PY 2003 VL 36 IS 5 BP 331 EP 333 DI 10.1002/mop.10757 PG 3 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA 650JV UT WOS:000181260800003 ER PT J AU Laird, KR Cumming, BF Wunsam, S Rusak, JA Oglesby, RJ Fritz, SC Leavitt, PR AF Laird, KR Cumming, BF Wunsam, S Rusak, JA Oglesby, RJ Fritz, SC Leavitt, PR TI Lake sediments record large-scale shifts in moisture regimes across the northern prairies of North America during the past two millennia SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID GREAT-PLAINS; DROUGHT FREQUENCY; CLIMATIC-CHANGE; UNITED-STATES; ENVIRONMENTAL-CHANGE; DIATOM ASSEMBLAGES; 1500-YEAR RECORD; AGE CALIBRATION; ELK LAKE; HOLOCENE AB Six high-resolution climatic reconstructions, based on diatom analyses from lake sediment cores from the northern prairies of North America, show that shifts in drought conditions on decadal through multicentennial scales have prevailed in this region for at least the last two millennia. The predominant broad-scale pattern seen at all sites is a major shift in moisture regimes from wet to dry, or vice versa (depending on location), that occurred after a period of relative stability. These large-scale shifts at the different sites exhibit spatial coherence at regional scales. The three Canadian sites record this abrupt shift between anno Domini 500 and 800, and subsequently conditions become increasingly variable. All three U.S. sites underwent a pronounced change, but the timing of this change is between anno Domini 1000 and 1300, thus later than in all of the Canadian sites. The mechanisms behind these patterns are poorly understood, but they are likely related to changes in the shape and location of the jet stream and associated storm tracks. If the patterns seen at these sites are representative of the region, this observed pattern can have huge implications for future water availability in this region. C1 Queens Univ, Dept Biol, Paleoecol Environm Assessment & Res Lab, Kingston, ON K7L 3N6, Canada. Univ Regina, Dept Biol, Limnol Lab, Regina, SK S4S 0A2, Canada. NASA, George C Marshall Space Flight Ctr, Natl Space Sci & Technol Ctr, Huntsville, AL 35805 USA. Univ Nebraska, Dept Geosci, Lincoln, NE 68588 USA. RP Cumming, BF (reprint author), Queens Univ, Dept Biol, Paleoecol Environm Assessment & Res Lab, Kingston, ON K7L 3N6, Canada. RI Leavitt, Peter/A-1048-2013; OI Leavitt, Peter/0000-0001-9805-9307; Rusak, James/0000-0002-4939-6478 NR 42 TC 96 Z9 98 U1 0 U2 16 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 MAR 4 PY 2003 VL 100 IS 5 BP 2483 EP 2488 DI 10.1073/pnas.0530193100 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 652DR UT WOS:000181365000059 PM 12606725 ER PT J AU Bauer, J Levine, LH AF Bauer, J Levine, LH TI Effect of lighting on dietary value of various scallions. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract CT 225th National Meeting of the American-Chemical-Society CY MAR 23-27, 2003 CL NEW ORLEANS, LA SP Amer Chem Soc C1 NASA, Kennedy Space Ctr, Kennedy Space Ctr, FL 32899 USA. EM jan.bauer-1@ksc.nasa.gov NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR PY 2003 VL 225 MA AGFD-049 BP U76 EP U76 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 761PU UT WOS:000187917800262 ER PT J AU Bottomley, LA Poggi, MA Lillehei, PT AF Bottomley, LA Poggi, MA Lillehei, PT TI Chemical force microscopy of single walled carbon nanotubes. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract CT 225th National Meeting of the American-Chemical-Society CY MAR 23-27, 2003 CL NEW ORLEANS, LA SP Amer Chem Soc C1 Georgia Inst Technol, Sch Chem & Biochem, Atlanta, GA 30332 USA. NASA, Langley Res Ctr, Adv Mat & Proc Branch, Hampton, VA 23665 USA. EM lawrence.bottomley@chemistry.gatech.edu RI Lillehei, Peter/C-9196-2009 OI Lillehei, Peter/0000-0001-8183-9980 NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR PY 2003 VL 225 MA 68-COLL BP U617 EP U618 PN 1 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 761PU UT WOS:000187917802819 ER PT J AU Clancy, TC Hinkley, JA AF Clancy, TC Hinkley, JA TI Multi-scale modeling of polyimides. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract CT 225th National Meeting of the American-Chemical-Society CY MAR 23-27, 2003 CL NEW ORLEANS, LA SP Amer Chem Soc C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. EM t.c.clancy@larc.nasa.gov NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR PY 2003 VL 225 MA 158-COMP BP U756 EP U757 PN 1 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 761PU UT WOS:000187917803489 ER PT J AU Cohn, CA Borda, M Schoonen, M AF Cohn, CA Borda, M Schoonen, M TI Fate of RNA in the presence of pyrite: relevance to the origin of life SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract CT 225th National Meeting of the American-Chemical-Society CY MAR 23-27, 2003 CL NEW ORLEANS, LA SP Amer Chem Soc C1 SUNY Stony Brook, Dept Geosci, Stony Brook, NY 11794 USA. NASA, Astrobiol Lab, Stony Brook, NY 11794 USA. EM ccohn@ic.sunysb.edu NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR PY 2003 VL 225 MA 029-GEOC BP U915 EP U915 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 761PU UT WOS:000187917804234 ER PT J AU Feldman, JD Stackpoole, M Ellerby, D Johnson, SM Blum, YG Sacks, MD AF Feldman, JD Stackpoole, M Ellerby, D Johnson, SM Blum, YG Sacks, MD TI Sol-gel derived hafnia coatings. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract CT 225th National Meeting of the American-Chemical-Society CY MAR 23-27, 2003 CL NEW ORLEANS, LOUISIANA SP Amer Chem Soc C1 NASA, Ames Res Ctr, ELORET, Moffett Field, CA 94035 USA. SRI Int, Menlo Pk, CA 94025 USA. Georgia Inst Technol, Sch Mat Sci & Engn, Atlanta, GA 30332 USA. EM jfeldman@socrates.berkeley.edu NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR PY 2003 VL 225 MA 627-INOR BP U106 EP U106 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 761PW UT WOS:000187918000622 ER PT J AU Filipek, LB Coon, CC Geiger, CL Clausen, CA Quinn, J DeVor, R AF Filipek, LB Coon, CC Geiger, CL Clausen, CA Quinn, J DeVor, R TI Dechlorination of polychlorinated biphenyls in solution by Pd/Fe bimetallic emulsions. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract CT 225th National Meeting of the American-Chemical-Society CY MAR 23-27, 2003 CL NEW ORLEANS, LA SP Amer Chem Soc C1 Univ Cent Florida, Dept Chem, Orlando, FL 32816 USA. Univ Cent Florida, Dept Chem, Kennedy Space Ctr, FL 32816 USA. NASA, Kennedy Space Ctr, FL USA. EM cgeiger@mail.ucf.edu NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR PY 2003 VL 225 MA 188-ENVR BP U827 EP U827 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 761PU UT WOS:000187917803899 ER PT J AU Geiger, CL Clausen, CA Brooks, KB Coon, CC Huntley, C Filipek, L DeVor, R Krug, TA O'Hara, S Major, D Quinn, J AF Geiger, CL Clausen, CA Brooks, KB Coon, CC Huntley, C Filipek, L DeVor, R Krug, TA O'Hara, S Major, D Quinn, J TI Remediation of DNAPLs using emulsified zero-valent iron: Laboratory and field results. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract CT 225th National Meeting of the American-Chemical-Society CY MAR 23-27, 2003 CL NEW ORLEANS, LA SP Amer Chem Soc C1 Univ Cent Florida, Dept Chem, Orlando, FL 32816 USA. NASA, Kennedy Space Ctr, FL USA. EM cgeiger@mail.ucf.edu NR 0 TC 1 Z9 1 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR PY 2003 VL 225 MA 137-ENVR BP U819 EP U819 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 761PU UT WOS:000187917803848 ER PT J AU Head-Gordon, M Weisman, J Lee, T AF Head-Gordon, M Weisman, J Lee, T TI Large-scale excited state calculations of polycyclic aromatic hydrocarbons: Unravelling the spectroscopic properties relevant to interstellar chemistry SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract CT 225th National Meeting of the American-Chemical-Society CY MAR 23-27, 2003 CL NEW ORLEANS, LA SP Amer Chem Soc C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Lawrence Berkeley Natl Lab, Div Chem Sci, Berkeley, CA 94720 USA. NASA, Ames Res Ctr, Moffett Field, CA USA. EM mhg@bastille.cchem.berkeley.edu NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR PY 2003 VL 225 MA 039-COMP BP U707 EP U707 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 761PU UT WOS:000187917803370 ER PT J AU Holland, DB Palou, JJ Williams, MK AF Holland, DB Palou, JJ Williams, MK TI Study of the degradation of high-performance polyimide foams SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract CT 225th National Meeting of the American-Chemical-Society CY MAR 23-27, 2003 CL NEW ORLEANS, LA SP Amer Chem Soc C1 Albion Coll, Dept Chem, Albion, MI 49224 USA. NASA, Kennedy Space Ctr, Mat Sci Lab, Washington, DC 20546 USA. EM dbh10@albion.edu NR 0 TC 0 Z9 0 U1 1 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR PY 2003 VL 225 MA 1040-CHED BP U511 EP U511 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 761PU UT WOS:000187917802346 ER PT J AU Hudson, DL Hinkley, JA Clancy, TC Reeves, MS AF Hudson, DL Hinkley, JA Clancy, TC Reeves, MS TI Molecular modeling of penetrants in aromatic polymides. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract CT 225th National Meeting of the American-Chemical-Society CY MAR 23-27, 2003 CL NEW ORLEANS, LOUISIANA SP Amer Chem Soc C1 Tuskegee Univ, Dept Chem, Tuskegee, AL 36088 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. CNR, Washington, DC 20418 USA. EM danielle.l.hudson@tusk.edu; mreeves@tusk.edu NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR PY 2003 VL 225 MA 172-POLY BP U557 EP U557 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 761PW UT WOS:000187918002869 ER PT J AU Kiefer, RL McGlothlin, DR Chapman, JL Thibeault, SA AF Kiefer, RL McGlothlin, DR Chapman, JL Thibeault, SA TI Materials for high-energy radiation shielding in space. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract CT 225th National Meeting of the American-Chemical-Society CY MAR 23-27, 2003 CL NEW ORLEANS, LOUISIANA SP Amer Chem Soc C1 Coll William & Mary, Dept Chem, Williamsburg, VA 23187 USA. NASA, Langley Res Ctr, Adv Mat & Proc Branch, Hampton, VA USA. EM rlkief@wm.edu NR 0 TC 1 Z9 1 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR PY 2003 VL 225 MA 180-POLY BP U558 EP U558 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 761PW UT WOS:000187918002877 ER PT J AU Kirby, JP AF Kirby, JP TI Terbium luminescence enhancements for bacterial spore detection SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract CT 225th National Meeting of the American-Chemical-Society CY MAR 23-27, 2003 CL NEW ORLEANS, LOUISIANA SP Amer Chem Soc C1 Fordham Univ, Dept Nat Sci, New York, NY 10023 USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. Univ Calif Berkeley, Berkeley, CA 94720 USA. EM jakirby@fordham.edu NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR PY 2003 VL 225 MA 229-INOR BP U44 EP U44 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 761PW UT WOS:000187918000226 ER PT J AU Kojiro, DR Sheverev, VA Khromov, NA Takeuchi, N Stimac, RM Kaye, WJ AF Kojiro, DR Sheverev, VA Khromov, NA Takeuchi, N Stimac, RM Kaye, WJ TI Chemical detection and identification techniques for exobiology flight experiments SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract CT 225th National Meeting of the American-Chemical-Society CY MAR 23-27, 2003 CL NEW ORLEANS, LA SP Amer Chem Soc C1 NASA, Ames Res Ctr, Exobiol Branch, Moffett Field, CA 94035 USA. EM dkojiro@mail.arc.nasa.gov NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR PY 2003 VL 225 MA 031-ANYL BP U111 EP U111 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 761PU UT WOS:000187917800437 ER PT J AU Koumoutsakos, P Walther, J Werder, T Zimmerli, U Jaffe, R AF Koumoutsakos, P Walther, J Werder, T Zimmerli, U Jaffe, R TI Water-carbon nanotube interactions: Potential energy calibration for molecular dynamics simulations using experiments and quantum system calculations SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract CT 225th National Meeting of the American-Chemical-Society CY MAR 23-27, 2003 CL NEW ORLEANS, LA SP Amer Chem Soc C1 ETH Zentrum, ICOS, CH-8092 Zurich, Switzerland. NASA, Ames Res Ctr, Moffett Field, CA USA. EM petros@inf.ethz.ch RI Koumoutsakos, Petros/A-2846-2008 OI Koumoutsakos, Petros/0000-0001-8337-2122 NR 0 TC 1 Z9 1 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR PY 2003 VL 225 MA 023-COMP BP U705 EP U705 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 761PU UT WOS:000187917803355 ER PT J AU Meador, MA Ilhan, F Kinder, JD Scheiman, DA AF Meador, MA Ilhan, F Kinder, JD Scheiman, DA TI Diels-Alder trapping of photoenols generated from 3,6-dibenzoyl-1,2-dimethylbenzene: A photochemical approach to the synthesis of substituted phenanthrenes. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract CT 225th National Meeting of the American-Chemical-Society CY MAR 23-27, 2003 CL NEW ORLEANS, LOUISIANA SP Amer Chem Soc C1 NASA, Glenn Res Ctr, Div Mat, Cleveland, OH 44135 USA. Ohio Aerosp Inst, Cleveland, OH 44142 USA. QSS Grp Inc, NASA Glenn, Lanham, MD 20706 USA. EM Michael.A.Meador@grc.nasa.gov; Ulvi.F.Ilhan@grc.nasa.gov NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR PY 2003 VL 225 MA 698-ORGN BP U415 EP U415 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 761PW UT WOS:000187918002101 ER PT J AU Meador, MAB Frimer, AA AF Meador, MAB Frimer, AA TI NMR guided design of end caps with improved oxidation resistance SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract CT 225th National Meeting of the American-Chemical-Society CY MAR 23-27, 2003 CL NEW ORLEANS, LOUISIANA SP Amer Chem Soc C1 NASA, Div Mat, Glenn Res Ctr, Cleveland, OH 44135 USA. Bar Ilan Univ, Ethel & David Resnick Chair Act Oxygen Chem, IL-52100 Ramat Gan, Israel. EM maryann.meador@grc.nasa.gov NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR PY 2003 VL 225 MA 340-POLY BP U581 EP U581 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 761PW UT WOS:000187918003037 ER PT J AU Palosz, B Grzanka, E Stelmakh, S Gierlotka, S Weber, HP Proffen, T Palosz, W AF Palosz, B Grzanka, E Stelmakh, S Gierlotka, S Weber, HP Proffen, T Palosz, W TI Examination of short- and long-range atomic order in nanocrystalline sic and diamond by powder diffraction methods SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract CT 225th National Meeting of the American-Chemical-Society CY MAR 23-27, 2003 CL NEW ORLEANS, LA SP Amer Chem Soc C1 High Pressure Res Ctr UNIPRESS, PL-01142 Warsaw, Poland. Los Alamos Natl Lab, Los Alamos, NM USA. NASA, George C Marshall Space Flight Ctr, SD46, USRA, Greenbelt, MD USA. EM palosz@unipress.waw.pl RI Lujan Center, LANL/G-4896-2012; Proffen, Thomas/B-3585-2009 OI Proffen, Thomas/0000-0002-1408-6031 NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR PY 2003 VL 225 MA 050-IEC BP U959 EP U959 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 761PU UT WOS:000187917804472 ER PT J AU Parker, JK Stief, LJ Payne, W Cody, R Nesbitt, F AF Parker, JK Stief, LJ Payne, W Cody, R Nesbitt, F TI First direct measurement of the rate constant for the reaction Cl+CH3 and a reexamination of its role in perturbing laboratory measurements of the important stratospheric reaction of Cl+CH4. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract CT 225th National Meeting of the American-Chemical-Society CY MAR 23-27, 2003 CL NEW ORLEANS, LOUISIANA SP Amer Chem Soc C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM jparker@lepvax.gsfc.nasa.gov RI Cody, Regina/D-5996-2013 NR 0 TC 1 Z9 1 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR PY 2003 VL 225 MA 296-PHYS BP U477 EP U477 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 761PW UT WOS:000187918002471 ER PT J AU Philpott, MR Jaffe, RL Lin, TT Goliney, IY Zhao, GP AF Philpott, MR Jaffe, RL Lin, TT Goliney, IY Zhao, GP TI Surface electrochemistry and origin of life problem. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract CT 225th National Meeting of the American-Chemical-Society CY MAR 23-27, 2003 CL NEW ORLEANS, LA SP Amer Chem Soc C1 NASA, Ames Res Ctr, Computat Chem Branch, Moffett Field, CA 94035 USA. Natl Univ Singapore, Dept Mat Sci, Singapore 117543, Singapore. EM chmmp@nus.edu.sg RI Lin, Ting Ting/F-8871-2012 NR 0 TC 0 Z9 0 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR PY 2003 VL 225 MA 574-COLL BP U696 EP U696 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 761PU UT WOS:000187917803323 ER PT J AU Ponce, A Lester, E Kirby, JP AF Ponce, A Lester, E Kirby, JP TI Online detection of aerosolized bacterial spores using dipicolinic acid triggered terbium luminescence. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract CT 225th National Meeting of the American-Chemical-Society CY MAR 23-27, 2003 CL NEW ORLEANS, LOUISIANA SP Amer Chem Soc C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Fordham Univ, Dept Nat Sci, Bronx, NY 10458 USA. EM Adrian.Ponce@jpl.nasa.gov NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR PY 2003 VL 225 MA 927-INOR BP U169 EP U169 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 761PW UT WOS:000187918000921 ER PT J AU Srivastava, D AF Srivastava, D TI Computational nanomechanics, reactivity and device applications of carbon nanotubes and fullerenes. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract CT 225th National Meeting of the American-Chemical-Society CY MAR 23-27, 2003 CL NEW ORLEANS, LA SP Amer Chem Soc C1 NASA, Ames Res Ctr, Computat Nanotechnol CSC NAS, Moffett Field, CA 94035 USA. EM deepak@nas.nasa.gov NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR PY 2003 VL 225 MA 104-COMP BP U748 EP U748 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 761PU UT WOS:000187917803435 ER PT J AU Wutz, C Samulski, ET Photinos, DJ Terzis, AF AF Wutz, C Samulski, ET Photinos, DJ Terzis, AF TI Ordering of apolar and polar solutes in nematic phases as determined by NMR spectroscopy. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract CT 225th National Meeting of the American-Chemical-Society CY MAR 23-27, 2003 CL NEW ORLEANS, LOUISIANA SP Amer Chem Soc C1 Univ Hamburg, Inst Tech & Makromol Chem, D-20146 Hamburg, Germany. Univ N Carolina, Dept Chem, Chapel Hill, NC 27515 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. Univ Patras, Dept Mat Sci, GR-26110 Patras, Greece. Univ Patras, Dept Phys, GR-26110 Patras, Greece. EM christoph.wutz@desy.de NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR PY 2003 VL 225 MA 438-POLY BP U596 EP U596 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 761PW UT WOS:000187918003135 ER PT J AU Zach, MP Mogul, R McMillan, A Paavola, C Trent, J Banfield, J AF Zach, MP Mogul, R McMillan, A Paavola, C Trent, J Banfield, J TI Heat shock proteins as templates for uniform arrays of semiconductor nanoparticles using ECALE. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract CT 225th National Meeting of the American-Chemical-Society CY MAR 23-27, 2003 CL NEW ORLEANS, LOUISIANA SP Amer Chem Soc C1 Univ Calif Berkeley, Miller Inst Basic Res Sci, Berkeley, CA 94720 USA. NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA USA. NASA, Ames Res Ctr, Astrobiol Technol Branch, Moffett Field, CA USA. Univ Calif Berkeley, Dept Earth & Planetary Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Environm Sci Policy & Management, Berkeley, CA 94720 USA. EM MZach@eps.berkeley.edu NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR PY 2003 VL 225 MA 832-INOR BP U154 EP U154 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 761PW UT WOS:000187918000826 ER PT J AU Zhang, GH Rawashdeh, AMM Sotiriou-Leventis, C Leventis, N AF Zhang, GH Rawashdeh, AMM Sotiriou-Leventis, C Leventis, N TI Isocyanate cross-linked silica: Structurally strong aerogels SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract CT 225th National Meeting of the American-Chemical-Society CY MAR 23-27, 2003 CL NEW ORLEANS, LOUISIANA SP Amer Chem Soc C1 Univ Missouri, Dept Chem, Rolla, MO 65409 USA. NASA, Polymer Branch, Div Mat, Glenn Res Ctr, Cleveland, OH 44135 USA. EM Nicholas:Leventis@grc.nasa.gov NR 0 TC 0 Z9 0 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR PY 2003 VL 225 MA 332-POLY BP U580 EP U580 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 761PW UT WOS:000187918003029 ER PT J AU Tavana, M Ortiz, JN Torney, SE AF Tavana, M Ortiz, JN Torney, SE TI Modeling station duty officer operations assistant at Johnson Space Center SO ADVANCES IN ENGINEERING SOFTWARE LA English DT Article DE NASA; automation technology; operations assistants; systems development; structures analysis; process modeling; data flow diagrams; Petri nets ID DATA FLOW DIAGRAMS; PETRI NETS; SYSTEMS; SPECIFICATION AB The mission operations directorate (MOD) at the Johnson Space Center (JSC) is responsible for the planning and operation of human space flight missions. MOD is being challenged with sustaining and developing new operations capabilities to support increasingly demanding requirements and to improve its processes to accomplish these missions at higher levels of safety, mission success, and effectiveness. Automation is being considered as an enabling technology to meet the aforementioned challenges. The synergistic combination of flight controllers and intelligent software providing the function of 'operations assistants' (OA) is being pursued as the key implementation of this technology in the Mission Control Center (MCC). The flight control team (FCT) assesses the condition and operability of the major systems such as electrical power, thermal control, life support, communications, altitude control, and data handling at MCC. OA assist the flight controllers with their tasks of monitoring the status and health of the flight systems. They also help maintain the flight controller's awareness of the operations being performed during the mission and help assure that operational objectives are being met. The station duty officer (SDO) performs the lead operations role for the International Space Station (ISS) during quiescent times when FCT and the flight director are off-duty. SDOs assess the condition and operability of the major ISS systems. This assessment involves monitoring and controlling several periodic processes on systems such as the electrical power, thermal control, life support, communications, altitude control, and data handling systems. The SDO is also responsible for coordinating operations with the Russian FCT. The OA will help the SDO maintain an awareness of all the processes performed on board and will assist with the responses to anomalous conditions. The OA for this position will support the concept of reduced control center staffing during quiescent times. The purpose of this paper is twofold: (1) to present a unique two-stage specification methodology that combines data flow diagrams and petri nets and (2) to apply the proposed methodology in a complex space station system. Published by Elsevier Science Ltd. C1 La Salle Univ, Dept Management, Philadelphia, PA 19141 USA. NASA, Syst Management Off, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NASA, Adv Projects & Anal Off, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Tavana, M (reprint author), La Salle Univ, Dept Management, Philadelphia, PA 19141 USA. NR 24 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0965-9978 J9 ADV ENG SOFTW JI Adv. Eng. Softw. PD MAR PY 2003 VL 34 IS 3 BP 139 EP 162 AR PII S0965-9978(02)00127-8 DI 10.1016/S0965-9978(02)00127-8 PG 24 WC Computer Science, Interdisciplinary Applications; Computer Science, Software Engineering; Engineering, Multidisciplinary SC Computer Science; Engineering GA 648GC UT WOS:000181141000002 ER PT J AU Hanson, JM AF Hanson, JM TI New guidance for new launchers SO AEROSPACE AMERICA LA English DT Article C1 NASA, Marshall, Trajectory & Guidance Team, Huntsville, AL 35812 USA. RP Hanson, JM (reprint author), NASA, Marshall, Trajectory & Guidance Team, Huntsville, AL 35812 USA. NR 0 TC 8 Z9 10 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0740-722X J9 AEROSPACE AM JI Aerosp. Am. PD MAR PY 2003 VL 41 IS 3 BP 36 EP 41 PG 6 WC Engineering, Aerospace SC Engineering GA 653NK UT WOS:000181431300012 ER PT J AU Saiyed, NH Mikkelsen, KL Bridges, JE AF Saiyed, NH Mikkelsen, KL Bridges, JE TI Acoustics and thrust of quiet separate-flow high-bypass-ratio nozzles SO AIAA JOURNAL LA English DT Article AB The NASA Glenn Research Center recently completed an experimental study to reduce the jet noise from modern turbofan engines. The study concentrated on exhaust nozzle designs for high-bypass-ratio engines. These designs modified the core and fan nozzles individually and simultaneously. In comparison with chevrons, tabs appeared to be an inefficient method for reducing jet noise. Data trends show that interaction between fan flow and the core cowl could strongly impact noise and cruise performance irrespective of the mixing device installed. The study demonstrates that modifications of the core nozzle are generally more advantageous than of the fan nozzle. Even greater advantage in noise reduction and associated cruise thrust penalties is demonstrated through simultaneous modification of both nozzles. The best nozzle design had a 0.06% cruise thrust loss and, corrected for takeoff thrust loss, a 2.7-EPNdB reduction for the effective perceived noise level metric. This design simultaneously employed chevrons on the core and fan nozzles. Last, five nozzle configurations with cruise thrust loss of less than 0.5% and noise reductions of over 2.5 EPNdB are identified as candidates for full-scale engine and flight demonstrations. C1 NASA, John H Glenn Res Ctr, Acoust Branch, Struct & Acoust Div, Cleveland, OH 44135 USA. Aero Syst Engn, St Paul, MN 55107 USA. RP Saiyed, NH (reprint author), NASA, John H Glenn Res Ctr, Acoust Branch, Struct & Acoust Div, Cleveland, OH 44135 USA. NR 13 TC 28 Z9 30 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD MAR PY 2003 VL 41 IS 3 BP 372 EP 378 DI 10.2514/2.1986 PG 7 WC Engineering, Aerospace SC Engineering GA 651QB UT WOS:000181330700003 ER PT J AU Zaman, KBMQ Wang, FY Georgiadis, NJ AF Zaman, KBMQ Wang, FY Georgiadis, NJ TI Noise, turbulence, and thrust of subsonic freejets from lobed nozzles SO AIAA JOURNAL LA English DT Article ID TRAILING-EDGE MODIFICATIONS; JET AB A study of noise benefit, vis-a-vis thrust penalty, and its correlation to turbulence intensities is conducted for freejets issuing from lobed nozzles. Four convergent nozzles with constant exit area are used in the experiments. Three of these are of rectangular lobed configuration having 6, 10, and 14 lobes; the fourth is a circular nozzle. Increasing the number of lobes results in a progressive reduction in the turbulence intensities as well as in the overall radiated noise. The noise reduction is pronounced at the low-frequency end of the spectrum. However, there is an increase in the high-frequency noise that renders the overall benefit less attractive when compared on a scaled-up A-weighted basis. Increasing the number of lobes involves progressive reduction in the thrust coefficient. The measured thrust loss is shown to be primarily caused by increased amount of low-momentum boundary-layer fluid over the stretched perimeter. It is inferred that a moderate number of lobes effectively reduce the noise, but increasing the number further results in a diminishing noise benefit and a rapidly increasing thrust penalty. An analysis, showing that the loss in thrust coefficient is proportional to the perimeter-to-diameter ratio and the inverse of the square root of the Reynolds number, provides a guideline for the choice of the lobe dimensions. C1 NASA, John H Glenn Res Ctr, Turbomachinery & Prop Syst Div, Cleveland, OH 44135 USA. RP Zaman, KBMQ (reprint author), NASA, John H Glenn Res Ctr, Turbomachinery & Prop Syst Div, Cleveland, OH 44135 USA. NR 22 TC 19 Z9 23 U1 1 U2 5 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD MAR PY 2003 VL 41 IS 3 BP 398 EP 407 DI 10.2514/2.1990 PG 10 WC Engineering, Aerospace SC Engineering GA 651QB UT WOS:000181330700006 ER PT J AU Sajben, M Cole, GL Slater, JW AF Sajben, M Cole, GL Slater, JW TI Acoustic and entropy pulses created in duct flows by rapid local events SO AIAA JOURNAL LA English DT Article C1 Univ Cincinnati, Dept Aerosp Engn & Engn Mech, Cincinnati, OH 45221 USA. NASA, John H Glenn Res Ctr Lewis Field, Inlet Branch, Cleveland, OH 44135 USA. RP Sajben, M (reprint author), Univ Cincinnati, Dept Aerosp Engn & Engn Mech, Cincinnati, OH 45221 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD MAR PY 2003 VL 41 IS 3 BP 538 EP 542 DI 10.2514/2.1978 PG 5 WC Engineering, Aerospace SC Engineering GA 651QB UT WOS:000181330700022 ER PT J AU Motil, BJ Balakotaiah, V Kamotani, Y AF Motil, BJ Balakotaiah, V Kamotani, Y TI Gas-liquid two-phase flow through packed beds in microgravity SO AICHE JOURNAL LA English DT Article ID PRESSURE-DROP; COCURRENT DOWNFLOW; REACTORS; HOLDUP; TRANSITION; MODEL; MAPS AB Experimental data on flow pattern transitions, pressure drop, and flow characteristics for cocurrent gas - liquid flow through packed columns in microgravity is analyzed. The pulse flow regime exists over a wider range of gas and liquid flow rates under microgravity conditions. Furthermore, maps used to predict transition boundaries in normal gravity do not apply in microgravity. The flow regime data are compared to the widely used Talmor map and a new transition criterion between bubble and pulse flow in microgravity is proposed. The pressure-drop data clearly show that interfacial effects can increase the pressure drop by as much as 300% compared to those predicted by the single-phase Ergun equation. A two-phase friction factor is correlated. to. the superficial gas and liquid Reynolds numbers and the Suratman number. New data are also presented on the influence of gravity on the pulse amplitude and frequency. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Univ Houston, Dept Chem Engn, Houston, TX 77204 USA. Case Western Reserve Univ, Dept Mech & Aerosp Engn, Cleveland, OH 44106 USA. RP Motil, BJ (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 24 TC 14 Z9 14 U1 2 U2 9 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 3 PARK AVE, NEW YORK, NY 10016-5901 USA SN 0001-1541 J9 AICHE J JI AICHE J. PD MAR PY 2003 VL 49 IS 3 BP 557 EP 565 DI 10.1002/aic.690490303 PG 9 WC Engineering, Chemical SC Engineering GA 654ZA UT WOS:000181525800002 ER PT J AU Grivel, JC Biancotto, A Ito, Y Lima, RG Margolis, LB AF Grivel, JC Biancotto, A Ito, Y Lima, RG Margolis, LB TI Bystander CD4(+) T lymphocytes survive in HIV-infected human lymphoid tissue SO AIDS RESEARCH AND HUMAN RETROVIRUSES LA English DT Article ID HUMAN-IMMUNODEFICIENCY-VIRUS; CELL DEPLETION; CROSS-LINKING; FAS LIGAND; EX-VIVO; APOPTOSIS; DEATH; MECHANISMS; ACTIVATION; HISTOCULTURES AB HIV infection is associated with depletion of CD4(+) T cells. The mechanisms of this phenomenon remain to be understood. In particular, it remains controversial whether and to what extent uninfected ("bystander") CD4(+) T cells die in HIV-infected individuals. We address this question using a system of human lymphoid tissue ex vivo. Tissue blocks were inoculated with HIV-1. After productive infection was established, they were treated with the reverse transcriptase inhibitor nevirapine to protect from infection those CD4(+) T cells that had not yet been infected. These CD4(+) T cells residing in HIV-infected tissue are by definition bystanders. Our results demonstrate that after nevirapine application the number of bystander CD4(+) T cells is conserved. Thus, in the context of HIV-infected human lymphoid tissue, productive HIV infection kills infected cells but is not sufficient to cause the death of a significant number of uninfected CD4(+) T cells. C1 NICHHD, Ctr Three Dimens Tissue Culture, NIH, Lab Mol & Cellular Biophys, Bethesda, MD 20892 USA. NICHHD, Ctr Three Dimens Tissue Culture, NIH, NASA, Bethesda, MD 20892 USA. RP Margolis, LB (reprint author), NICHHD, Ctr Three Dimens Tissue Culture, NIH, Lab Mol & Cellular Biophys, Bldg 10,Room 9D58,9000 Rockville Pike, Bethesda, MD 20892 USA. NR 30 TC 11 Z9 12 U1 0 U2 0 PU MARY ANN LIEBERT INC PUBL PI LARCHMONT PA 2 MADISON AVENUE, LARCHMONT, NY 10538 USA SN 0889-2229 J9 AIDS RES HUM RETROV JI Aids Res. Hum. Retrovir. PD MAR PY 2003 VL 19 IS 3 BP 211 EP 216 DI 10.1089/088922203763315713 PG 6 WC Immunology; Infectious Diseases; Virology SC Immunology; Infectious Diseases; Virology GA 655KM UT WOS:000181551000006 PM 12689413 ER PT J AU Bu, XR Vanderveer, D Santos, J Hsu, FL Wang, J Bota, K AF Bu, XR Vanderveer, D Santos, J Hsu, FL Wang, J Bota, K TI Crystal structure of 4,5-bis(4-dimethylaminophenyl)-2-(4-nitrophenyl)imidazole SO ANALYTICAL SCIENCES LA English DT Article ID NONLINEAR-OPTICAL CHROMOPHORES AB A nonlinear optical chromophore, 4,5-bis(4-dimethylaminophenyl)-2-(4-nitrophenyl)imidazole, was investigated by Xray crystallography. The study focused on coplanarity among several aromatic rings, including phenyls and imidazole. Two phenyl rings with NMe2 groups are twisted by 46.39(3)degrees from each other. However, they are twisted by 23.05(5)degrees and 46.84(3)degrees from the imidazole, respectively. These unequal twists were elucidated by different conjugation pathways from the donors to the acceptor. The phenyl ring with the NO2 group is twisted by only 6.76(6)degrees from the imidazole. C1 Clark Atlanta Univ, Dept Chem, Atlanta, GA 30314 USA. Clark Atlanta Univ, NASA, Ctr High Performance Polymers & Composites, Atlanta, GA 30314 USA. Georgia Inst Technol, Sch Chem & Biochem, Atlanta, GA 30332 USA. USA, Edgewood Chem & Biol Ctr, Aberdeen Proving Ground, MD 21010 USA. RP Bu, XR (reprint author), Clark Atlanta Univ, Dept Chem, Atlanta, GA 30314 USA. NR 4 TC 5 Z9 5 U1 0 U2 1 PU JAPAN SOC ANALYTICAL CHEMISTRY PI TOKYO PA 26-2 NISHIGOTANDA 1 CHOME SHINAGAWA-KU, TOKYO, 141, JAPAN SN 0910-6340 J9 ANAL SCI JI Anal. Sci. PD MAR PY 2003 VL 19 IS 3 BP 469 EP 470 DI 10.2116/analsci.19.469 PG 2 WC Chemistry, Analytical SC Chemistry GA 655MZ UT WOS:000181557800028 PM 12675363 ER PT J AU Khan, H Lester, M Davies, JA Milan, SE Sandholt, PE AF Khan, H Lester, M Davies, JA Milan, SE Sandholt, PE TI Multi-instrument study of the dynamic cusp during dominant IMF B-y conditions SO ANNALES GEOPHYSICAE LA English DT Article DE ionosphere; ionosphere-magnetosphere interactions; particle precipitation; magnetospheric physics ID FLUX-TRANSFER EVENTS; INTERPLANETARY MAGNETIC-FIELD; DAYSIDE AURORAL ACTIVITY; HF RADAR OBSERVATIONS; HIGH-LATITUDE CONVECTION; CUTLASS FINLAND RADAR; EISCAT SVALBARD RADAR; IONOSPHERIC CONVECTION; VELOCITY-MEASUREMENTS; PLASMA CONVECTION AB We present multi-instrument observations using the meridian scanning photometer (MSP) at Ny Alesund, the EISCAT Svalbard radar (ESR) and the CUTLASS Finland HF radar, to investigate the dynamics of the cusp region during pulsed reconnection events. The optical data obtained from the MSP indicate the presence of several poleward-moving auroral forms (PMAFs) which have been previously identified as the auroral signature of pulsed reconnection. Furthermore, the optical green line (557.7 nm) luminosity indicates a loss of emission equatorward of the location of the onset of the PMAFs, characteristic of magnetospheric plasma escaping to the magnetosheath along newly opened field lines. This reduction in green line luminosity creates a "dark region", the equatorward edge of which is found to lie close to the boundary between high and low spectral widths observed by the CUTLASS Finland radar. High spectral widths on the dayside have previously been identified as a good indicator of cusp backscatter. Both of these boundaries have been suggested to provide an accurate representation of the location of the open/closed field line boundary. The ESR observations show enhancements in electron density and electron temperature occurring in conjunction with the optical PMAFs. The observations demonstrate some correspondence with the theoretical predictions of Davis and Lockwood (1996), who used an auroral precipitation model to predict ESR observations in the vicinity of the cusp. However, the limitations of this model are apparent under conditions of large plasma flows in the ionosphere. Finally, convection velocities obtained from the HF radar data illustrate a flow regime similar to that predicted to be driven by strong IMF By, as described by Cowley and Lockwood (1992), demonstrating an initial azimuthal flow followed by a rotation to more poleward directions. C1 NASA, Goddard Space Flight Ctr, Interplanetary Phys Branch, Greenbelt, MD 20771 USA. Univ Leicester, Leicester LE1 7RH, Leics, England. Univ Oslo, N-0316 Oslo, Norway. RP Khan, H (reprint author), NASA, Goddard Space Flight Ctr, Interplanetary Phys Branch, Greenbelt, MD 20771 USA. EM hkhan@lepvax.gsfc.nasa.gov NR 63 TC 3 Z9 3 U1 0 U2 2 PU EUROPEAN GEOPHYSICAL SOC PI KATLENBURG-LINDAU PA MAX-PLANCK-STR 13, 37191 KATLENBURG-LINDAU, GERMANY SN 0992-7689 J9 ANN GEOPHYS-GERMANY JI Ann. Geophys. PD MAR PY 2003 VL 21 IS 3 BP 693 EP 708 PG 16 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA 775MX UT WOS:000189046100009 ER PT J AU Cockell, CS Osinski, GR Lee, P AF Cockell, CS Osinski, GR Lee, P TI The impact crater as a habitat: Effects of impact processing of target materials SO ASTROBIOLOGY LA English DT Article; Proceedings Paper CT 10th Rubey Colloquium CY FEB 08-09, 2002 CL LOS ANGELES, CALIFORNIA DE crater; impact; succession; recolonization; Haughton; Breccia ID MOUNT-ST-HELENS; DEVON ISLAND; POLAR DESERT; PLANT-DISTRIBUTION; HAUGHTON FORMATION; VOLCANIC-ERUPTION; ARCTIC CANADA; NWT; ENVIRONMENT; VEGETATION AB Impact structures are a rare habitat on Earth. However, where they do occur they can potentially have an important influence on the local ecology. Some of the types of habitat created in the immediate post-impact environment are not specific to the impact phenomenon, such as hydrothermal systems and crater lakes that can be found, for instance, in post-volcanic environments, albeit with different thermal characteristics than those associated with impact. However, some of the habitats created are specifically linked to processes of impact processing. Two examples of how impact processing of target materials has created novel habitats that improve the opportunities for colonization are found in the Haughton impact structure in the Canadian High Arctic. Impact-shocked rocks have become a habitat for endolithic microorganisms, and large, impact-shattered blocks of rock are used as resting sites by avifauna. However, some materials produced by an impact, such as melt sheet rocks, can make craters more biologically depauperate than the area surrounding them. Although there are no recent craters with which to study immediate post-impact colonization, these data yield insights into generalized mechanisms of how impact processing can influence post-impact succession. Because impact events are one of a number of processes that can bring localized destruction to ecosystems, understanding the manner in which impact structures are recolonized is of ecological interest. Impact craters are a universal phenomenon on solid planetary surfaces, and so they are of potential biological relevance on other planetary surfaces, particularly Mars. C1 NASA, Ames Res Ctr, SETI Inst, Moffett Field, CA 94035 USA. Univ New Brunswick, Dept Geol, Planetary & Space Sci Ctr, Fredericton, NB, Canada. RP Cockell, CS (reprint author), British Antarctic Survey, High Cross,Madingley Rd, Cambridge CB1 3AR, England. NR 35 TC 31 Z9 31 U1 0 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 SPR PY 2003 VL 3 IS 1 BP 181 EP 191 DI 10.1089/153110703321632507 PG 11 WC Astronomy & Astrophysics; Biology; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics; Geology GA 676LF UT WOS:000182753000013 PM 12804371 ER PT J AU Morrison, D AF Morrison, D TI Impacts and evolution: Future prospects SO ASTROBIOLOGY LA English DT Article; Proceedings Paper CT 10th Rubey Colloquium CY FEB 08-09, 2002 CL LOS ANGELES, CALIFORNIA DE impacts; mass extinctions; asteroids; impact hazard; Cretaceous-Tertiary extinction; spaceguard survey ID NEAR-EARTH ASTEROIDS; CRETACEOUS-TERTIARY BOUNDARY; TUNGUSKA; EXTINCTION; OBJECTS; HAZARD; SHOEMAKER-LEVY-9; FRAGMENTATION; ATMOSPHERE; POPULATION AB The discipline of astrobiology includes the dynamics of biological evolution. One of the major ways that the cosmos influences life is through the catastrophic environmental disruptions caused when comets and asteroids collide with a planet. We now recognize that such impacts have caused mass extinctions and played a major role in determining the evolution of life on Earth. The time-averaged impact flux as a function of projectile energy can be derived from lunar cratering statistics as well as the current population of near Earth asteroids (NEAs). Effects of impacts of various energies can be modeled, using data from historic impacts [such as the Cretaceous-Tertiary (KT) impactor 65 million years ago] and the observed 1994 bombardment of Jupiter by fragments of Comet Shoemaker-Levy 9. It is of particular interest to find from such models that the terrestrial environment is highly vulnerable to perturbation from impacts, so that even such a small event as the KT impact (by a projectile 10-15 km. in diameter) can lead to a mass extinction. Similar considerations allow us to model the effects of still smaller (and much more likely) impacts, down to the size of the asteroid that exploded over Tunguska in 1908 (energy similar to10 megatons). Combining the impact flux with estimates of environmental and ecological effects reveals that the greatest contemporary hazard is associated with impactors near 1 million megatons in energy (similar to2 km in diameter for an asteroid). The current impact hazard is significant relative to other natural hazards, and arguments can be developed to illuminate a variety of public policy issues. The first priority in any plan for defense against impactors is to survey the population of Earth-crossing NEAs and project their orbits forward in time. This is the purpose of the Spaceguard Survey, which has already found more than half of the NEAs >1 km in diameter. If there is an NEA on a collision course with Earth, it can be discovered and the impact predicted with decades or more of warning. It is then possible to consider how to deflect or disrupt the NEA. Unlike other natural hazards, the impact risk can be largely eliminated, given sufficient advanced knowledge to take action against the threatening projectile. C1 NASA, Astrobiol Inst, Mountain View, CA 94035 USA. RP Morrison, D (reprint author), NASA, Astrobiol Inst, Ames 240-1, Mountain View, CA 94035 USA. NR 84 TC 2 Z9 2 U1 2 U2 6 PU MARY ANN LIEBERT INC PUBL PI LARCHMONT PA 2 MADISON AVENUE, LARCHMONT, NY 10538 USA SN 1531-1074 J9 ASTROBIOLOGY JI Astrobiology PD SPR PY 2003 VL 3 IS 1 BP 193 EP 205 DI 10.1089/153110703321632516 PG 13 WC Astronomy & Astrophysics; Biology; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics; Geology GA 676LF UT WOS:000182753000014 PM 12804372 ER PT J AU Rhoads, JE Dey, A Malhotra, S Stern, D Spinrad, H Jannuzi, BT Dawson, S Brown, MJI Landes, E AF Rhoads, JE Dey, A Malhotra, S Stern, D Spinrad, H Jannuzi, BT Dawson, S Brown, MJI Landes, E TI Spectroscopic confirmation of three redshift z not approximate to 5.7 Ly alpha emitters from the Large-Area Lyman Alpha survey SO ASTRONOMICAL JOURNAL LA English DT Article DE cosmology : observations; early universe; galaxies : distances and redshifts; galaxies : evolution; galaxies : formation; galaxies : high-redshift ID GUNN-PETERSON TROUGH; HUBBLE DEEP FIELD; STAR-FORMATION; LUMINOSITY DENSITY; KECK SPECTROSCOPY; EMISSION-LINE; GALAXIES; REIONIZATION; EVOLUTION; RADIATION AB Narrowband searches for Lyalpha emission are an efficient way of identifying star-forming galaxies at high redshifts. We present Keck Telescope spectra confirming redshifts z approximate to 5.7 for three objects discovered in the Large-Area Lyman Alpha ( LALA) survey at Kitt Peak National Observatory. All three spectra show strong, narrow emission lines with the asymmetric pro le that is characteristically produced in high-redshift Lyalpha emitters by preferential H I absorption in the blue wing of the line. These objects are undetected in deep B-W, V, R, and lambda = 6600 Angstrom narrowband images from the NOAO Deep Wide-Field Survey and from LALA, as expected from Lyman break and Lyalpha forest absorption at redshift z approximate to 5.7. All three objects show large equivalent widths (greater than or similar to150 Angstrom in the rest frame), suggesting at least one of the following: a top-heavy initial mass function, very low stellar metallicity, or the presence of an active nucleus. We consider the case for an active nucleus to be weak in all three objects due to the limited width of the Lyalpha emission line ( less than 500 km s(-1)) and the absence of any other indicator of quasar activity. The three confirmed high-redshift objects were among four spectroscopically observed targets drawn from the sample of 18 candidates presented by Rhoads & Malhotra. Thus, these spectra support the Lyalpha emitter population statistics from our earlier photometric study, which imply little evolution in number density from z = 5.7 to 4.5 and provide strong evidence that the reionization redshift is z(r) > 5.7. C1 Space Telescope Sci Inst, Baltimore, MD 21218 USA. Kitt Peak Natl Observ, Tucson, AZ 85726 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. RP Rhoads, JE (reprint author), Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA. RI Brown, Michael/B-1181-2015 OI Brown, Michael/0000-0002-1207-9137 NR 48 TC 172 Z9 172 U1 0 U2 3 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 MAR PY 2003 VL 125 IS 3 BP 1006 EP 1013 DI 10.1086/346272 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 647LR UT WOS:000181094700002 ER PT J AU Dawson, S McCrady, N Stern, D Eckart, ME Spinrad, H Liu, MC Graham, JR AF Dawson, S McCrady, N Stern, D Eckart, ME Spinrad, H Liu, MC Graham, JR TI Optical and near-infrared spectroscopy of a high-redshift hard X-ray-emitting spiral galaxy SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : high-redshift; galaxies : individual (CXOHDFN J123635.6+621424); galaxies : Seyfert; galaxies : spiral; quasars : emission lines ID HUBBLE-DEEP-FIELD; RESOLUTION IMAGING SPECTROMETER; EMISSION-LINE SPECTRA; RADIO GALAXIES; STELLAR POPULATIONS; CLASSIFICATION; MORPHOLOGY; EVOLUTION; NORTH; ULTRAVIOLET AB We present optical and near-infrared Keck spectroscopy of CXOHDFN J123635.6+621424 (HDFX 28), a hard X-ray source at a redshift of z = 2.011 in the flanking fields of the Hubble Deep Field North (HDF-N). HDFX 28 is a red source (R-K-s = 4.74) with extended steep-spectrum (alpha(1.4)(8.4) GHz > 0. 87 GHz) microjansky radio emission and significant emission (441 muJy) at 15 mum. Accordingly, initial investigations prompted the interpretation that HDFX 28 is powered by star formation. Subsequent Chandra imaging, however, revealed hard (Gamma = 0.30) X-ray emission indicative of absorbed active galactic nucleus (AGN) activity, implying that HDFX 28 is an obscured type II AGN. The optical and near-infrared spectra presented herein corroborate this result; the near-infrared emission lines cannot be powered by star formation alone, and the optical emission lines indicate a buried AGN. HDFX 28 is identified with a face-on moderately late-type spiral galaxy. Multiwavelength morphological studies of the HDF-N have heretofore revealed no galaxies with any kind of recognizable spiral structure beyond z > 2. We present a quantitative analysis of the morphology of HDFX 28, and we find the measures of central concentration and asymmetry to be indeed consistent with those expected for a rare high-redshift spiral galaxy. C1 Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Div Phys Math & Astron, Pasadena, CA 91125 USA. RP Dawson, S (reprint author), Univ Calif Berkeley, Dept Astron, Mail Code 3411, Berkeley, CA 94720 USA. NR 82 TC 25 Z9 25 U1 0 U2 3 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 MAR PY 2003 VL 125 IS 3 BP 1236 EP 1246 DI 10.1086/367792 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 647LR UT WOS:000181094700021 ER PT J AU Lane, BF Colavita, MM AF Lane, BF Colavita, MM TI Phase-referenced stellar interferometry at the Palomar Testbed Interferometer SO ASTRONOMICAL JOURNAL LA English DT Article DE instrumentation : interferometers techniques : interferometric AB We discuss implementation and testing of phase referencing at the Palomar Testbed Interferometer. A new instrument configuration provides a coherent integration of 10 or 20 ms on a bright star while stabilizing the fringe phase of a nearby (20") and faint visual companion, allowing coherent integration times of at least 250 ms. Observations have been made of several visual binaries, including 16 Cyg AB (m(K) = 4.5 and m(K) = 4.6) and HD 173648/49 (m(K) = 4.3 and m(K) similar to 5) to test the performance of the technique. These measurements also demonstrate that phase-referenced visibility measurements can be calibrated at the level of 3%-7%. C1 CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lane, BF (reprint author), CALTECH, Div Geol & Planetary Sci, 150-21,1200 E Calif Blvd, Pasadena, CA 91125 USA. NR 9 TC 20 Z9 20 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD MAR PY 2003 VL 125 IS 3 BP 1623 EP 1628 DI 10.1086/367793 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 647LR UT WOS:000181094700053 ER PT J AU Gorosabel, J Christensen, L Hjorth, J Fynbo, JU Pedersen, H Jensen, BL Andersen, MI Lund, N Jaunsen, AO Ceron, JMC Castro-Tirado, AJ Fruchter, A Greiner, J Pian, E Vreeswijk, PM Burud, I Frontera, F Kaper, L Klose, S Kouveliotou, C Masetti, N Palazzi, E Rhoads, J Rol, E Salamanca, I Tanvir, N Wijers, RAMJ van den Heuvel, E AF Gorosabel, J Christensen, L Hjorth, J Fynbo, JU Pedersen, H Jensen, BL Andersen, MI Lund, N Jaunsen, AO Ceron, JMC Castro-Tirado, AJ Fruchter, A Greiner, J Pian, E Vreeswijk, PM Burud, I Frontera, F Kaper, L Klose, S Kouveliotou, C Masetti, N Palazzi, E Rhoads, J Rol, E Salamanca, I Tanvir, N Wijers, RAMJ van den Heuvel, E TI A multi-colour study of the dark GRB 000210 host galaxy and its environment SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE gamma rays : bursts; galaxies : fundamental parameters; techniques : photometric ID GAMMA-RAY BURSTS; LUMINOSITY FUNCTION; INTERSTELLAR EXTINCTION; OPTICAL AFTERGLOW; MAGELLANIC CLOUD; NEUTRON-STARS; EXPLOSIONS; VELOCITIES; EVOLUTION; RADIATION AB We present UBVRIZJsHKs broad band photometry of the host galaxy of the dark gamma-ray burst (GRB) of February 10, 2000. These observations represent the most exhaustive photometry given to date of any GRB host galaxy. A grid of spectral templates have been fitted to the Spectral Energy Distribution (SED) of the host. The derived photometric redshift is z = 0.842(-0.042)(+0.014), which is in excellent agreement with the spectroscopic redshift (z = 0.8463 +/- 0.0002) proposed by Piro et al. (2002) based on a single emission line. Furthermore, we have determined the photometric redshift of all the galaxies in an area of 6' x 6' around the host galaxy, in order to check for their overdensity in the environment of the host. We find that the GRB 000210 host galaxy is a subluminous galaxy (L similar to 0.5 +/- 0.2 L*), with no companions above our detection threshold of 0.18 +/- 0.06 L*. Based on the restframe ultraviolet flux a star formation rate of 2.1 +/- 0.2 M, yr(-1) is estimated. The best fit to the SED is obtained for a starburst template with an age of 0.181(-0.026)(+0.037) Gyr and a very low extinction (A(v) similar to 0). We discuss the implications of the inferred low value of Av and the age of the dominant stellar population for the non-detection of the GRB 000210 optical afterglow. C1 Danish Space Res Inst, DK-2100 Copenhagen O, Denmark. CSIC, Inst Astrofis Andalucia, E-18080 Granada, Spain. LAEFF INTA, Madrid 28080, Spain. Univ Copenhagen, Astron Observ, DK-2100 Copenhagen O, Denmark. Inst Astrophys, D-14482 Potsdam, Germany. Aarhus Univ, Dept Phys & Astron, DK-8000 Aarhus C, Denmark. European So Observ, Santiago 19, Chile. Real Inst, Secc Astron, Cadiz 11110, Spain. Observ Armada, Secc Astron, Cadiz 11110, Spain. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Max Planck Inst Extraterr Phys, D-85741 Garching, Germany. Osserv Astron Trieste, I-34131 Trieste, Italy. Univ Ferrara, Dipartmento Fis, I-44100 Ferrara, Italy. CNR, Ist Tecnol & Studio Radiaz Extraterrestri, I-40129 Bologna, Italy. Univ Amsterdam, NL-1098 SJ Amsterdam, Netherlands. Thuringer Landessternwarte Tautenburg, D-07778 Tautenburg, Germany. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Hertfordshire, Dept Phys Sci, Hatfield AL10 9AB, Herts, England. RP Gorosabel, J (reprint author), Danish Space Res Inst, Juliane Maries Vej 30, DK-2100 Copenhagen O, Denmark. EM jgu@dsri.dk; lise@astro.ku.dk; jens@astro.ku.dk; jfynbo@phys.au.dk; holger@astro.ku.dk; brian_j@astro.ku.dk; mandersen@aip.de; nl@dsri.dk; ajaunsen@eso.org; josemari@alumni.nd.edu; ajct@iaa.es; fruchter@stsci.edu; jgreiner@aip.de; pian@tesre.bo.cnr.it; pvreeswi@eso.org; burud@stsci.edu; frontera@fe.infn.it; lexk@science.uva.nl; klose@tls-tautenburg.de; kouveliotou@eagles.msfc.nasa.gov; masetti@bo.iasf.cnr.it; eliana@bo.iasf.cnr.it; rhoads@stsci.edu; evert@science.uva.nl; isabel@science.uva.nl; nrt@star.herts.ac.uk; rwijers@science.uva.nl; edvdh@science.uva.nl RI Fynbo, Johan/L-8496-2014; Christensen, Lise/M-5301-2014; Hjorth, Jens/M-5787-2014; Jensen, Brian Lindgren/E-1275-2015; Palazzi, Eliana/N-4746-2015; OI Fynbo, Johan/0000-0002-8149-8298; Christensen, Lise/0000-0001-8415-7547; Hjorth, Jens/0000-0002-4571-2306; Pian, Elena/0000-0001-8646-4858; Jensen, Brian Lindgren/0000-0002-0906-9771; Wijers, Ralph/0000-0002-3101-1808; Palazzi, Eliana/0000-0002-8691-7666; Castro-Tirado, A. J./0000-0003-2999-3563; Masetti, Nicola/0000-0001-9487-7740 NR 46 TC 57 Z9 58 U1 0 U2 1 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAR PY 2003 VL 400 IS 1 BP 127 EP 136 DI 10.1051/0004-6361:20021907 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 648XT UT WOS:000181177300015 ER PT J AU Stahl, O Gang, T Sterken, C Kaufer, A Rivinius, T Szeifert, T Wolf, B AF Stahl, O Gang, T Sterken, C Kaufer, A Rivinius, T Szeifert, T Wolf, B TI Long-term spectroscopic monitoring of the Luminous Blue Variable HD 160529 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars : individual : HD 160529; stars : early-type; stars : emission-line, Be; stars : variables : general; stars : mass-loss ID BA-TYPE SUPERGIANTS; LTE LINE FORMATION; MAGELLANIC CLOUD; STELLAR-WIND; MODEL ATOM; S-DORADUS; MASS-LOSS; P-CYGNI; STARS; ESO AB We have spectroscopically monitored the galactic Luminous Blue Variable HD 160529 and obtained an extensive high-resolution data set that covers the years 1991 to 2002. During this period, the star evolved from an extended photometric minimum phase towards a new visual maximum. In several observing seasons, we covered up to four months with almost daily spectra. Our spectra typically cover most of the visual spectral range with a high spectral resolution (lambda/Deltalambda approximate to 20 000 or more). This allows us to investigate the variability in many lines and on many time scales from days to years. We find a correlation between the photospheric HeI lines and the brightness of the star, both on a time scale of months and on a time scale of years. The short-term variations are smaller and do not follow the long-term trend, strongly suggesting different physical mechanisms. Metal lines also show both short-term and long-term variations in strength and also a long-term trend in radial velocity. Most of the line-profile variations can be attributed to changing strengths of lines. Propagating features in the line profiles are rarely observed. We find that the mass-loss rate of HD 160529 is almost independent of temperature, i.e. visual brightness. C1 Landessternwarte Konigstuhl, D-69117 Heidelberg, Germany. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Free Univ Brussels, Astron Grp, B-1050 Brussels, Belgium. European So Observ, D-85748 Garching, Germany. RP Stahl, O (reprint author), Landessternwarte Konigstuhl, D-69117 Heidelberg, Germany. NR 45 TC 23 Z9 23 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 MAR PY 2003 VL 400 IS 1 BP 279 EP 291 DI 10.1051/0004-6361:20021908 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 648XT UT WOS:000181177300029 ER PT J AU Duchene, G Menard, F Stapelfeldt, K Duvert, G AF Duchene, G Menard, F Stapelfeldt, K Duvert, G TI A layered edge-on circumstellar disk around HK Tau B SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars : formation; stars : planetary systems : protoplanetary disks; stars : pre-main sequence; stars : individual : HK Tau ID BINARY STAR-FORMATION; T-TAURI; ACCRETION DISKS; SIZE DISTRIBUTION; GG-TAURI; CIRCUMBINARY DISK; DUST; CLOUDS; GRAINS; EXTINCTION AB We present the first high angular resolution 1.4 mm and 2.7 mm continuum maps of the T Tauri binary system HK Tau obtained with the Plateau de Bure Interferometer. The contributions of both components are well disentangled at 1.4 mm and the star previously known to host an edge-on circumstellar disk, HK Tau B, is elongated along the disk's major axis. The optically bright primary dominates the thermal emission from the system at both wavelengths, confirming that it also has its own circumstellar disk. Its non-detection in scattered light images indicates that the two disks in this binary system are not parallel. Our data further indicate that the circumprimary disk is probably significantly smaller than the circumsecondary disk. We model the millimeter thermal emission from the circumstellar disk surrounding HK Tau B. We show that the disk mass derived from scattered light images cannot reproduce the 1.4 mm emission using opacities of the same population of submicron dust grains. However, grain growth alone cannot match all the observed properties of this disk. We propose that this disk contains three separate layers: two thin outer surfaces which contain dust grains that are very similar to those of the ISM, and a disk interior which is relatively massive and/or has experienced limited grain growth with the largest grains significantly smaller than 1 mm. Such a structure could naturally result from dust settling in a protoplanetary disk. C1 Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. Univ Grenoble 1, Observ Grenoble, Astrophys Lab, F-38041 Grenoble 9, France. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Duchene, G (reprint author), Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. RI Stapelfeldt, Karl/D-2721-2012 NR 41 TC 27 Z9 27 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 MAR PY 2003 VL 400 IS 2 BP 559 EP 565 DI 10.1051/0004-6361:20021906 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 651AW UT WOS:000181298700018 ER PT J AU Andretta, V Del Zanna, G Jordan, SD AF Andretta, V Del Zanna, G Jordan, SD TI The EUV helium spectrum in the quiet Sun: A by-product of coronal emission? SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE radiative transfer; line : formation; Sun : chromosphere; Sun : corona; Sun : UV radiation ID SOLAR TRANSITION REGION; DIAGNOSTIC SPECTROMETER; SPECTROSCOPIC DIAGNOSTICS; ANOMALOUS INTENSITIES; CROSS-SECTIONS; ACTIVE-REGION; SOHO MISSION; THIN PLASMAS; LINES; CALIBRATION AB In this paper we test one of the mechanisms proposed to explain the intensities and other observed properties of the solar helium spectrum, and in particular of its Extreme-Ultraviolet (EUV) resonance lines. The so-called Photoionisation-Recombination (P-R) mechanism involves photoionisation of helium atoms and ions by EUV coronal radiation, followed by recombination cascades. We present calibrated measurements of EUV flux obtained with the two CDS spectrometers on board SOHO, in quiescent solar regions. We were able to obtain an essentially complete estimate of the total photoionising flux in the wavelength range below 504 Angstrom (the photoionisation threshold for He I), as well as simultaneous measurements with the same instruments of the intensities of the strongest EUV He I and He II lines: He I lambda584, He I lambda537, and He II lambda304. We find that there are not enough EUV ionising photons to account for the observed helium line intensities. More specifically, we conclude that He II intensities cannot be explained by the P-R mechanism alone. Our results, however, leave open the possibility that the He I spectrum could be formed by the P-R mechanism, with the He II lambda304 line as a significant photoionisating source. C1 Osserv Astron Capodimonte, Ist Nazl Astrofis, I-80131 Naples, Italy. Univ Cambridge, Dept Appl Math & Theoret Phys, Cambridge CB3 9EW, England. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Andretta, V (reprint author), Osserv Astron Capodimonte, Ist Nazl Astrofis, Salita Moiariello 16, I-80131 Naples, Italy. OI Andretta, Vincenzo/0000-0003-1962-9741 NR 62 TC 41 Z9 41 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 MAR PY 2003 VL 400 IS 2 BP 737 EP 752 DI 10.1051/0004-6361:20021893 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 651AW UT WOS:000181298700036 ER PT J AU Benoit, A Ade, P Amblard, A Ansari, R Aubourg, E Bargot, S Bartlett, JG Bernard, JP Bhatia, RS Blanchard, A Bock, JJ Boscalerilo, A Bouchet, FR Bourrachot, A Camus, P Couchot, E de Bernardis, P Delabrouille, J Desert, EX Dore, O Douspis, M Dumoulin, L Dupac, X Filliatre, P Fosalba, P Ganga, K Gannaway, E Gautier, B Giard, A Giraud-Heraud, Y Gispert, R Guglielmi, L Hamilton, JC Hanany, S Henrot-Versille, S Kaplan, J Lagache, G Lamarre, JM Lange, AE Macias-Perez, JE Madet, K Maffei, B Magneville, C Marrone, DP Masi, S Mayet, F Murphy, A Naraghi, E Nati, F Patanchon, G Perrin, G Piat, M Ponthieu, N Prunet, S Puget, JL Renault, C Rosset, C Santos, D Starobinsky, A Strukov, I Sudiwala, RV Teyssier, R Tristram, M Tucker, C Vanel, JC Vibert, D Wakui, E Yvon, D AF Benoit, A Ade, P Amblard, A Ansari, R Aubourg, E Bargot, S Bartlett, JG Bernard, JP Bhatia, RS Blanchard, A Bock, JJ Boscalerilo, A Bouchet, FR Bourrachot, A Camus, P Couchot, E de Bernardis, P Delabrouille, J Desert, EX Dore, O Douspis, M Dumoulin, L Dupac, X Filliatre, P Fosalba, P Ganga, K Gannaway, E Gautier, B Giard, A Giraud-Heraud, Y Gispert, R Guglielmi, L Hamilton, JC Hanany, S Henrot-Versille, S Kaplan, J Lagache, G Lamarre, JM Lange, AE Macias-Perez, JE Madet, K Maffei, B Magneville, C Marrone, DP Masi, S Mayet, F Murphy, A Naraghi, E Nati, F Patanchon, G Perrin, G Piat, M Ponthieu, N Prunet, S Puget, JL Renault, C Rosset, C Santos, D Starobinsky, A Strukov, I Sudiwala, RV Teyssier, R Tristram, M Tucker, C Vanel, JC Vibert, D Wakui, E Yvon, D TI Cosmological constraints from Archeops SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE cosmic microwave background; cosmological parameters; early Universe; large-scale structure of the Universe ID ANGULAR POWER SPECTRUM; MICROWAVE BACKGROUND ANISOTROPIES; GALAXY CLUSTERS; PARAMETERS; MAXIMA-1 AB We analyze the cosmological constraints that Archeops (Benoit et al. 2003) places on adiabatic cold dark matter models with passive power-law initial fluctuations. Because its angular power spectrum has small bins in l and large l coverage down to COBE scales, Archeops provides a precise determination of the first acoustic peak in terms of position at multipole l(peak) = 220 +/- 6, height and width. An analysis of Archeops data in combination with other CMB datasets constrains the baryon content of the Universe, Omega(b)h(2) = 0.022(-0.004)(+0.003), compatible with Big-Bang nucleosynthesis and with a similar accuracy. Using cosmological priors obtained from recent non-CMB data leads to yet tighter constraints on the total density, e.g. Q(tot) = 1.00(-0.02)(+0.03) using the HST determination of the Hubble constant. An excellent absolute calibration consistency is found between Archeops and other CMB experiments, as well as with the previously quoted best fit model. The spectral index n is measured to be 1.04(-0.12)(+0.10) when the optical depth to reionization, tau, is allowed to vary as a free parameter, and 0.96(-0.04)(+0.03) when tau is fixed to zero, both in good agreement with inflation. C1 CNRS, Ctr Rech Tres Basses Temp, F-38042 Grenoble 9, France. Cardiff Univ, Dept Phys, Cardiff CF24 3YB, S Glam, Wales. Coll France, F-75231 Paris 5, France. Lab Accelerateur Lineaire, F-91898 Orsay, France. Ctr Etud Saclay, CEA, DAPNIA, Serv Phys Particules, F-91191 Gif Sur Yvette, France. Observ Midi Pyrenees, Astrophys Lab, F-31400 Toulouse, France. Univ Paris 11, Inst Astrophys Spatiale, F-91405 Orsay, France. CALTECH, Ctr Infrared Proc & Anal, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CNR, IROE, I-50127 Florence, Italy. Inst Astrophys, F-75014 Paris, France. Univ Roma La Sapienza, Dipartimento Fis, Grp Cosmol Sperimentale, I-00185 Rome, Italy. Observ Grenoble, Astrophys Lab, F-38041 Grenoble 9, France. Nucl & Astrophys Lab, Oxford OX1 3RH, England. Ctr Spectrometrie Nucl & Spectrometrie Masse, IN2P3, F-91405 Orsay, France. Ctr Etud Spatiale Rayonnements, F-31028 Toulouse 4, France. Inst Sci Nucl Grenoble, F-38026 Grenoble, France. Univ Minnesota, Sch Phys & Astron, Minneapolis, MN 55455 USA. Natl Univ Ireland, Maynooth, Kildare, Ireland. LD Landau Theoret Phys Inst, Moscow 119334, Russia. Moscow Space Res Inst, Moscow 117810, Russia. Ctr Etud Saclay, CEA, DAPNIA, Serv Astrophys, F-91191 Gif Sur Yvette, France. Univ Paris 07, Federat Rech APC, Paris, France. Observ Paris, LERMA, F-75014 Paris, France. RP Benoit, A (reprint author), CNRS, Ctr Rech Tres Basses Temp, BP 166, F-38042 Grenoble 9, France. EM benoit@grenoble.cnrs.fr RI Bouchet, Francois/B-5202-2014; amblard, alexandre/L-7694-2014; Yvon, Dominique/D-2280-2015; Fosalba Vela, Pablo/I-5515-2016; Nati, Federico/I-4469-2016; OI Bouchet, Francois/0000-0002-8051-2924; amblard, alexandre/0000-0002-2212-5395; Nati, Federico/0000-0002-8307-5088; Marrone, Daniel/0000-0002-2367-1080 NR 38 TC 161 Z9 162 U1 0 U2 7 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAR PY 2003 VL 399 IS 3 BP L25 EP L30 DI 10.1051/0004-6361:20021722 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 646QR UT WOS:000181046200002 ER PT J AU Benoit, A Ade, P Amblard, A Ansari, R Abourg, E Bargot, S Bartlett, JG Bernard, JP Bhatia, RS Blanchard, A Bock, JJ Boscaleri, A Bouchet, FR Bourrachot, A Camus, P Couchot, F de Bernardis, P Delabrouille, J Desert, FX Dore, O Douspis, M Dumoulin, L Dupac, X Filliatre, P Fosalba, P Ganga, K Gannaway, F Gautier, B Giard, M Giraud-Heraud, Y Gispert, R Guglielmi, L Hamilton, JC Hanany, S Henrot-Versille, S Kaplan, J Lagache, G Lamarre, JM Lange, AE Macias-Perez, JF Madet, K Maffei, B Magneville, C Marrone, DP Masi, S Mayet, F Murphy, A Naraghi, F Nati, F Patanchon, G Perrin, G Piat, M Ponthieu, N Prunet, S Puget, JL Renault, C Rosset, C Santos, D Starobinsky, A Strukov, I Sudiwala, RV Teyssier, R Tristram, M Tucker, C Vanel, JC Vibert, D Wakui, E Yvon, D AF Benoit, A Ade, P Amblard, A Ansari, R Abourg, E Bargot, S Bartlett, JG Bernard, JP Bhatia, RS Blanchard, A Bock, JJ Boscaleri, A Bouchet, FR Bourrachot, A Camus, P Couchot, F de Bernardis, P Delabrouille, J Desert, FX Dore, O Douspis, M Dumoulin, L Dupac, X Filliatre, P Fosalba, P Ganga, K Gannaway, F Gautier, B Giard, M Giraud-Heraud, Y Gispert, R Guglielmi, L Hamilton, JC Hanany, S Henrot-Versille, S Kaplan, J Lagache, G Lamarre, JM Lange, AE Macias-Perez, JF Madet, K Maffei, B Magneville, C Marrone, DP Masi, S Mayet, F Murphy, A Naraghi, F Nati, F Patanchon, G Perrin, G Piat, M Ponthieu, N Prunet, S Puget, JL Renault, C Rosset, C Santos, D Starobinsky, A Strukov, I Sudiwala, RV Teyssier, R Tristram, M Tucker, C Vanel, JC Vibert, D Wakui, E Yvon, D TI The cosmic microwave background anisotropy power spectrum measured by Archeops SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE cosmic microwave background; cosmology : observations; submillimeter ID MAPS; RADIATION AB We present a determination by the Archeops experiment of the angular power spectrum of the cosmic microwave background anisotropy in 16 bins over the multipole range l = 15-350. Archeops was conceived as a precursor of the Planck HFI instrument by using the same optical design and the same technology for the detectors and their cooling. Archeops is a balloon-borne instrument consisting of a 1.5 m aperture diameter telescope and an array of 21 photometers maintained at similar to100 mK that are operating in 4 frequency bands centered at 143, 217, 353 and 545 GHz. The data were taken during the Arctic night of February 7, 2002 after the instrument was launched by CNES from Esrange base (Sweden). The entire data cover similar to30% of the sky. This first analysis was obtained with a small subset of the dataset using the most sensitive photometer in each CMB band (143 and 217 GHz) and 12.6% of the sky at galactic latitudes above 30 degrees where the foreground contamination is measured to be negligible. The large sky coverage and medium resolution (better than 15 arcmin) provide for the first time a high signal-to-noise ratio determination of the power spectrum over angular scales that include both the first acoustic peak and scales probed by COBE/DMR. With a binning of Deltat = 7 to 25 the error bars are dominated by sample variance for l below 200. A companion paper details the cosmological implications. C1 CNRS, Ctr Rech Tres Basses Temp, F-38042 Grenoble 9, France. Cardiff Univ, Dept Phys, Cardiff CF24 3YB, S Glam, Wales. Coll France, F-75231 Paris 5, France. Lab Accelerateur Lineaire, F-91898 Orsay, France. Ctr Etud Saclay, CEA, DAPNIA, Serv Phys Particules, F-91191 Gif Sur Yvette, France. Observ Midi Pyrenees, Astrophys Lab, F-31400 Toulouse, France. Univ Paris 11, Inst Astrophys Spatiale, F-91405 Orsay, France. CALTECH, Ctr Infrared Proc & Anal, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CNR, IROE, I-50127 Florence, Italy. Inst Astrophys, F-75014 Paris, France. Univ Roma La Sapienza, Dipartimento Fis, Grp Cosmol Sperimentale, I-00185 Rome, Italy. Observ Grenoble, Astrophys Lab, F-38041 Grenoble 9, France. Nucl & Astrophys Lab, Oxford OX1 3RH, England. Ctr Spectrometrie Nucl & Spectrometrie Masse, IN2P3, F-91405 Orsay, France. Ctr Etud Spatiale Rayonnements, F-31028 Toulouse 4, France. Inst Sci Nucl Grenoble, F-38026 Grenoble, France. Univ Minnesota, Sch Phys & Astron, Minneapolis, MN 55455 USA. Natl Univ Ireland, Maynooth, Kildare, Ireland. LD Landau Theoret Phys Inst, Moscow 119334, Russia. Moscow Space Res Inst, Moscow 117810, Russia. Ctr Etud Saclay, CEA, DAPNIA, Serv Astrophys, F-91191 Gif Sur Yvette, France. Univ Paris 07, Federat Rech APC, Paris, France. Observ Paris, LERMA, F-75014 Paris, France. RP Benoit, A (reprint author), CNRS, Ctr Rech Tres Basses Temp, BP 166, F-38042 Grenoble 9, France. RI Bouchet, Francois/B-5202-2014; amblard, alexandre/L-7694-2014; Yvon, Dominique/D-2280-2015; Fosalba Vela, Pablo/I-5515-2016; Nati, Federico/I-4469-2016; OI amblard, alexandre/0000-0002-2212-5395; Nati, Federico/0000-0002-8307-5088; Marrone, Daniel/0000-0002-2367-1080; Bouchet, Francois/0000-0002-8051-2924 NR 27 TC 133 Z9 133 U1 0 U2 5 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 MAR PY 2003 VL 399 IS 3 BP L19 EP L23 DI 10.1051/0004-6361:20021850 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 646QR UT WOS:000181046200001 ER PT J AU Arendt, RG Dwek, E AF Arendt, RG Dwek, E TI An empirical decomposition of near-infrared emission into Galactic and extragalactic components SO ASTROPHYSICAL JOURNAL LA English DT Article DE diffuse radiation; dust, extinction; Galaxy : stellar content; infrared : galaxies; infrared : ISM; infrared : stars ID COBE DIRBE MAPS; BACKGROUND EXPERIMENT SEARCH; DUST EMISSION; MICRONS; LIGHT; GALAXIES; DESIGN; EXCESS; LIMITS; MODEL AB We decompose the COBE/DIRBE observations of the near-IR sky brightness (minus zodiacal light) into Galactic stellar and interstellar medium (ISM) components and an extragalactic background. This empirical procedure allows us to estimate the 4.9 mum cosmic infrared background (CIB) as a function of the CIB intensity at shorter wavelengths. A weak indication of a rising CIB intensity at lambda>3.5 mum hints at interesting astrophysics in the CIB spectrum, or warns that the foreground zodiacal emission may be incompletely subtracted. Subtraction of only the stellar component from the zodiacal-light subtracted all-sky map reveals the clearest 3.5 mum ISM emission map, which is found to be tightly correlated with the ISM emission at far-IR wavelengths. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Arendt, RG (reprint author), NASA, Goddard Space Flight Ctr, Code 685, Greenbelt, MD 20771 USA. NR 36 TC 16 Z9 16 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 MAR 1 PY 2003 VL 585 IS 1 BP 305 EP 318 DI 10.1086/345983 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 646QV UT WOS:000181046500026 ER PT J AU Rodgers, SD Charnley, SB AF Rodgers, SD Charnley, SB TI Chemical evolution in protostellar envelopes: Cocoon chemistry SO ASTROPHYSICAL JOURNAL LA English DT Article DE astrochemistry; ISM : abundances; ISM : clouds; molecular processes; stars : formation ID HOT MOLECULAR CORES; MASSIVE STAR-FORMATION; YOUNG STELLAR OBJECTS; COMET HALE-BOPP; ORGANIC-MOLECULES; INTERSTELLAR ICES; FORMING REGIONS; CARBON-DIOXIDE; COMPACT RIDGE; LINE EMISSION AB We have modeled the chemistry that occurs in the envelopes surrounding newborn stars as they are gradually heated by the embedded protostar and the ice mantles of dust grains evaporate, resulting in a hot molecular core. We consider two dynamical scenarios: (1) a cloud undergoing the "inside-out" gravitational collapse calculated by Shu and (2) a quasi-stationary envelope. The radial distribution of dust temperature means that differences in surface binding energies result in distinct spatial zones with specific chemistries, as more volatile species (e.g., H2S) are evaporated before more tightly bound species (e.g., H2O). We use our results to identify chemical features that depend on the nature of the collapse and so determine observational tests that may be able to distinguish between different dynamical models of the star formation process. We show that the observed molecular abundances in massive hot cores can be explained only if these objects are supported against collapse. C1 NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. RP Rodgers, SD (reprint author), NASA, Ames Res Ctr, Div Space Sci, MS 245-3, Moffett Field, CA 94035 USA. RI Charnley, Steven/C-9538-2012 NR 91 TC 84 Z9 84 U1 1 U2 5 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 1 PY 2003 VL 585 IS 1 BP 355 EP 371 DI 10.1086/345497 PN 1 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 646QV UT WOS:000181046500030 ER PT J AU Lee, J Gallagher, PT Gary, DE Nita, GM Choe, GS Bong, SC Yun, HS AF Lee, J Gallagher, PT Gary, DE Nita, GM Choe, GS Bong, SC Yun, HS TI H alpha, extreme-ultraviolet, and microwave observations of the 2000 March 22 solar flare and spontaneous magnetic reconnection SO ASTROPHYSICAL JOURNAL LA English DT Article DE MHD; radiation mechanisms : nonthermal; Sun : flares; Sun : magnetic fields; Sun : radio radiation; Sun : UV radiation ID QUASI-SEPARATRIX LAYERS; X-RAY OBSERVATIONS; SPATIAL-RESOLUTION; BURSTS; MODEL; CONFIGURATION; RADIATION; TOPOLOGY; CORONA; LOOPS AB The evolution of a GOES class X1.1 solar are, which occurred in NOAA Active Region 8910 on 2000 March 22, is discussed using observations from the Owens Valley Solar Array (OVSA), Big Bear Solar observatory (BBSO), Transition Region and Coronal Explorer (TRACE), and the Michelson Doppler Imager (MDI) on board Solar and Heliospheric Observatory (SOHO). During the impulsive phase, a set of coronal loops are visible in the TRACE 171 Angstrom (similar to 1 X 10(6) K) wavelength band, which is confined to a small volume in the center of the large betagammadelta-type active region. This is rapidly followed by the emergence of bright Halpha ribbons that coincide with the EUV emission. Radio images show a single source encompassing the Halpha ribbons at 5 GHz, but at higher frequencies a double source is seen within the area bounded by the compact Halpha and EUV emissions. We interpret the observation under the idea of the confined are in contrast with the more commonly cited, eruptive are. We use a schematic magnetic reconnection geometry based on the MDI magnetogram to suggest that the EUV loops show some parts of a separatrix, and that the radio and Halpha sources coincide with the whole part of the separatrix and its footpoints, respectively. First of all, it explains why this are lacks the separating motion of Halpha ribbons, a signature for eruptive flares. Second, the very short duration of microwave bursts in spite of the large amount of soft X-ray flux is explicable under this scenario, since energy release via spontaneous reconnection in a confined magnetic structure can be very rapid. Third, the confined magnetic geometry is also considered favorable for preserving chromospheric evaporation and plasma turbulence as inferred from the OVSA microwave spectrum. In addition, a coronal mass ejection as detected in the LASCO coronagraph after this flare is briefly discussed in relation to the above are model. C1 New Jersey Inst Technol, Dept Phys, Newark, NJ 07102 USA. NASA, L3 Commun Analyt Corp, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Princeton Univ, Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. Seoul Natl Univ, SEES, Astron Program, Seoul 151742, South Korea. RP Lee, J (reprint author), New Jersey Inst Technol, Dept Phys, Newark, NJ 07102 USA. RI Choe, Gwangson/E-2366-2013; Gallagher, Peter/C-7717-2011 OI Gallagher, Peter/0000-0001-9745-0400 NR 54 TC 15 Z9 15 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 MAR 1 PY 2003 VL 585 IS 1 BP 524 EP 535 DI 10.1086/346024 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 646QV UT WOS:000181046500045 ER PT J AU Page, L Jackson, C Barnes, C Bennett, C Halpern, M Hinshaw, G Jarosik, N Kogut, A Limon, M Meyer, SS Spergel, DN Tucker, GS Wilkinson, DT Wollack, E Wright, EL AF Page, L Jackson, C Barnes, C Bennett, C Halpern, M Hinshaw, G Jarosik, N Kogut, A Limon, M Meyer, SS Spergel, DN Tucker, GS Wilkinson, DT Wollack, E Wright, EL TI The optical design and characterization of the Microwave Anisotropy Probe SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic microwave background; cosmology : observations; dark matter; early universe; space vehicles : instruments; telescopes ID BACKGROUND-RADIATION ANISOTROPY; SCALE ANISOTROPY; REFLECTOR ANTENNAS; POWER SPECTRUM; ANGULAR SCALE; TELESCOPE; INTERFEROMETER; INSTRUMENT; SURFACE; OFFSET AB The primary goal of the MAP satellite, now in orbit, is to make high-fidelity polarization-sensitive maps of the full sky in five frequency bands between 20 and 100 GHz. From these maps we will characterize the properties of the cosmic microwave background (CMB) anisotropy and Galactic and extragalactic emission on angular scales ranging from the effective beam size, less than 0.degrees23, to the full sky. MAP is a differential microwave radiometer. Two back-to-back shaped offset Gregorian telescopes feed two mirror symmetric arrays of 10 corrugated feeds. We describe the prelaunch design and characterization of the optical system, compare the optical models to the measurements, and consider multiple possible sources of systematic error. C1 Princeton Univ, Dept Phys, Princeton, NJ 08544 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ British Columbia, Dept Phys & Astron, Vancouver, BC V6T 1Z4, Canada. Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. Princeton Univ, Dept Astrophys Sci, Princeton, NJ 08544 USA. Brown Univ, Dept Phys, Providence, RI 02912 USA. Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. RP Page, L (reprint author), Princeton Univ, Dept Phys, Jadwin Hall,POB 708, Princeton, NJ 08544 USA. EM page@princeton.edu RI Kogut, Alan/D-6293-2012; Spergel, David/A-4410-2011; Wollack, Edward/D-4467-2012 OI Wollack, Edward/0000-0002-7567-4451 NR 89 TC 56 Z9 56 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 MAR 1 PY 2003 VL 585 IS 1 BP 566 EP 586 DI 10.1086/346078 PN 1 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 646QV UT WOS:000181046500048 ER PT J AU Bhatia, AK Landi, E AF Bhatia, AK Landi, E TI Atomic data and spectral line intensities for SiVII SO ASTROPHYSICAL JOURNAL LA English DT Article DE atomic data; plasmas ID EMISSION-LINES; SI-VII; GROUND CONFIGURATION; COLLISION STRENGTHS; RATE COEFFICIENTS; CROSS-SECTIONS; IRON PROJECT; SOLAR; IONS; TRANSITIONS AB Electron impact collision strengths, energy levels, oscillator strengths, and spontaneous radiative decay rates are calculated for the Si VII configurations 2s(2)2p(4), 2s2p(5), 2p(6), 2s(2)2p(3)3s, 2s(2)2p(3)3p, and 2s(2)2p(3)3d, giving rise to 86 fine-structure levels in intermediate coupling. Collision strengths are calculated at five incident energies, 15, 30, 45, 60, and 75 ryd, using the distorted wave approximation. Excitation rate coefficients are calculated as a function of electron temperature by assuming a Maxwellian electron velocity distribution. Using the excitation rate coefficients and the radiative transition rates, statistical equilibrium equations for level populations are solved at electron densities covering the range of 10(8)-10(14) cm(-3) assuming an electron temperature of log T-e(K) = 5.8, corresponding to maximum ionic abundance of Si VII. Relative spectral line intensities are calculated. Proton excitation rates between the lowest three levels have been included in the statistical equilibrium equations. The predicted Si VII line intensities are compared with Solar EUV Rocket Telescope and Spectrograph (SERTS) observations in NOAA Active Region 5464 and Solar Ultraviolet Measurement of Emitted Radiation (SUMER) observations of the quiet Sun. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Artep Inc, Ellicott City, MD 21042 USA. RP Bhatia, AK (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Landi, Enrico/H-4493-2011 NR 40 TC 7 Z9 8 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 MAR 1 PY 2003 VL 585 IS 1 BP 587 EP 597 DI 10.1086/345930 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 646QV UT WOS:000181046500049 ER PT J AU Mulchaey, JS Davis, DS Mushotzky, RF Burstein, D AF Mulchaey, JS Davis, DS Mushotzky, RF Burstein, D TI An X-ray atlas of groups of galaxies SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE galaxies : clusters : general; X-rays : galaxies : clusters ID ALL-SKY SURVEY; COMPACT-GROUPS; ROSAT OBSERVATIONS; DARK-MATTER; POOR GROUPS; HOT GAS; INTERGALACTIC GAS; SCALING RELATIONS; NEARBY GROUPS; CFA SURVEY AB A search was conducted for a hot intragroup medium in 109 low-redshift galaxy groups observed with the ROSAT PSPC. Evidence for diffuse, extended X-ray emission is found in at least 61 groups. Approximately one-third of these detections have not been previously reported in the literature. Most of the groups are detected out to less than half of the virial radius with ROSAT. Although some spiral-rich groups do contain an intragroup medium, diffuse emission is restricted to groups that contain at least one early-type galaxy. C1 Carnegie Inst Washington Observ, Pasadena, CA 91101 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Joint Ctr Astrophys, Baltimore, MD 21228 USA. Arizona State Univ, Dept Phys & Astron, Tempe, AZ 85287 USA. RP Mulchaey, JS (reprint author), Carnegie Inst Washington Observ, 813 Santa Barbara St, Pasadena, CA 91101 USA. NR 70 TC 141 Z9 143 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD MAR PY 2003 VL 145 IS 1 BP 39 EP 64 DI 10.1086/345736 PG 26 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 648KX UT WOS:000181151500003 ER PT J AU Bhatia, AK Landi, E Mason, HE AF Bhatia, AK Landi, E Mason, HE TI Atomic data and spectral line intensities for Ni XXI SO ATOMIC DATA AND NUCLEAR DATA TABLES LA English DT Article ID I ISOELECTRONIC-SEQUENCES; 2S22PK-2S2PK+1 TRANSITIONS; RATE COEFFICIENTS; CROSS-SECTIONS; TOKAMAK PLASMA; FE; NICKEL; IRON; WAVELENGTHS; CHROMIUM AB Electron impact collision strengths, energy levels, oscillator strengths and spontaneous radiative decay rates are calculated for Ni XXI. The configurations used are 2s(2)2p(4), 2s2p(5), 2p(6), 2s(2)2p(3)3s, and 2s(2)3p(3)3d giving rise to 58 fine-structure levels in intermediate coupling. Collision strengths are calculated at five incident energies, 85, 170, 255, 340, and 425 Ry. Excitation rate coefficients are calculated by assuming a Maxwellian electron velocity distribution at an electron temperature of log T-e(K) = 6.9, corresponding to maximum abundance of Ni XXI. Using the excitation rate coefficients and the radiative transition rates, statistical equilibrium equations for level populations are solved at electron densities 10(8)-10(14) cm(-1). Relative spectral line intensities are calculated. Proton excitation rates between the lowest three levels have been included in the statistical equilibrium equations. The predicted intensity ratios are compared with available observations, (C) 2003 Elsevier Science (USA). All rights reserved. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. USN, Res Lab, Washington, DC 20375 USA. Univ Cambridge, Dept Appl Math & Theoret Phys, Cambridge CB3 9EW, England. RP Bhatia, AK (reprint author), NASA, Goddard Space Flight Ctr, Code 681, Greenbelt, MD 20771 USA. RI Landi, Enrico/H-4493-2011 NR 32 TC 23 Z9 23 U1 0 U2 2 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0092-640X J9 ATOM DATA NUCL DATA JI Atom. Data Nucl. Data Tables PD MAR PY 2003 VL 83 IS 2 BP 71 EP 112 DI 10.1016/S0092-640X(03)00011-1 PG 42 WC Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Physics GA 676KC UT WOS:000182749800001 ER PT J AU Bhatia, AK Thomas, RJ Landi, E AF Bhatia, AK Thomas, RJ Landi, E TI Atomic data and spectral line intensities for Ne III SO ATOMIC DATA AND NUCLEAR DATA TABLES LA English DT Article ID ACTIVE-REGION SPECTRUM; EMISSION-LINES; CROSS-SECTIONS; RATE COEFFICIENTS; ELECTRON-IMPACT; ORION NEBULA; EXCITATION; ABUNDANCE; DENSITIES; ANGSTROM AB Electron impact collision strengths, energy levels, oscillator strengths and spontaneous radiative decay rates are calculated for Ne III. The configurations used are 2s(2)2p(4), 2s2p(5), 2s(2)2p(3)3s, and 2s(2)2p(3)3d giving rise to 57 fine-structure levels in intermediate coupling. Collision strengths are calculated at five incident energies, 5, 15, 25, 35, and 45 Ry. Excitation rate coefficients are calculated by assuming a Maxwellian electron velocity distribution at an electron temperature of log T-e(K) = 5.0, corresponding to maximum abundance of Ne III. Using the excitation rate coefficients and the radiative transition rates, statistical equilibrium equations for level populations are solved at electron densities covering 'the range of 10(8)-10(14) cm(-3). Relative spectral line intensities are calculated. Proton excitation rates between the lowest three levels have been included in the statistical equilibrium equations. The predicted Ne III line intensities are compared with SERTS rocket measurements of a solar active region and of a laboratory EUV light source. (C) 2003 Elsevier Science (USA). All rights reserved. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. USN, Res Lab, Washington, DC 20375 USA. RP Bhatia, AK (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Landi, Enrico/H-4493-2011 NR 37 TC 7 Z9 7 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 0092-640X J9 ATOM DATA NUCL DATA JI Atom. Data Nucl. Data Tables PD MAR PY 2003 VL 83 IS 2 BP 113 EP 152 DI 10.1016/S0092-640X(03)00012-3 PG 40 WC Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Physics GA 676KC UT WOS:000182749800002 ER PT J AU Li, SH Cordero, EC Karoly, DJ AF Li, SH Cordero, EC Karoly, DJ TI Three-dimensional simulations of springtime dissipation of the Antarctic ozone hole SO AUSTRALIAN METEOROLOGICAL MAGAZINE LA English DT Article ID METEOROLOGYS GLOBAL ASSIMILATION; GENERAL-CIRCULATION MODEL; POLAR VORTEX; PREDICTION SYSTEM; MIDDLE ATMOSPHERE; TRANSPORT; EVOLUTION; DEPLETION; AEROSOL; BUREAU AB A three-dimensional offline transport model is used to study the evolution of the Antarctic ozone hole in spring 1994. The modelled ozone profiles generated using winds from the UK Meteorological Office (UKMO), including the whole stratosphere, are closer to observations than simulations driven by operational weather analyses from the Global Assimilation and Prediction system (GASP), with highest level at 10 hPa. Model simulations are also fairly insensitive to horizontal or temporal resolution of the input driving fields, particularly at middle and high latitudes. While the large-scale synoptic variations in simulated total ozone are in good agreement with satellite observations, the model underpredicts total ozone at high latitudes during the ozone hole recovery phase. Further analysis suggests that the polar stratospheric clouds (PSC) chemical parametrisation is not appropriate for the specific spring of 1994. In addition, our results also suggest that dynamics are partially responsible for the slower than observed recovery of column ozone. C1 Monash Univ, Sch Math Sci, Clayton, Vic 3168, Australia. RP Li, SH (reprint author), NASA, Data Assimilat Off, Goddard Space Flight Ctr, Code 910-4, Greenbelt, MD 20771 USA. RI Karoly, David/C-8262-2011 OI Karoly, David/0000-0002-8671-2994 NR 30 TC 0 Z9 0 U1 0 U2 0 PU AUSTRALIAN GOVT PUBL SERV PI CANBERRA PA PO BOX 84, CANBERRA, 2601, AUSTRALIA SN 0004-9743 J9 AUST METEOROL MAG JI Aust. Meteorol. Mag. PD MAR PY 2003 VL 52 IS 1 BP 1 EP 9 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 676VX UT WOS:000182774200001 ER PT J AU Schenker, PS AF Schenker, PS TI Untitled - Introduction SO AUTONOMOUS ROBOTS LA English DT Editorial Material C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Schenker, PS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0929-5593 J9 AUTON ROBOT JI Auton. Robot. PD MAR-MAY PY 2003 VL 14 IS 2-3 BP 99 EP 99 DI 10.1023/A:1022211116265 PG 1 WC Computer Science, Artificial Intelligence; Robotics SC Computer Science; Robotics GA 641JL UT WOS:000180741600001 ER PT J AU Bejczy, AK AF Bejczy, AK TI Untitled - Preface SO AUTONOMOUS ROBOTS LA English DT Editorial Material C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0929-5593 J9 AUTON ROBOT JI Auton. Robot. PD MAR-MAY PY 2003 VL 14 IS 2-3 BP 101 EP 102 DI 10.1023/A:1022219300335 PG 2 WC Computer Science, Artificial Intelligence; Robotics SC Computer Science; Robotics GA 641JL UT WOS:000180741600002 ER PT J AU Schenker, PS Huntsberger, TL Pirjanian, P Baumgartner, ET Tunstel, E AF Schenker, PS Huntsberger, TL Pirjanian, P Baumgartner, ET Tunstel, E TI Planetary rover developments supporting Mars exploration, sample return and future human-robotic colonization SO AUTONOMOUS ROBOTS LA English DT Article; Proceedings Paper CT 10th International Conference on Advanced Robotics CY AUG 22-25, 2001 CL BUDAPEST, HUNGARY DE mobile robots; cooperating robots; all terrain mobility; robotic colonies; robot architecture; reconfigurable; robots AB We overview our recent research on planetary mobility. Products of this effort include the Field Integrated Design & Operations rover (FIDO), Sample Return Rover (SRR), reconfigurable rover units that function as an All Terrain Explorer (ATE), and a multi-Robot Work Crew of closely cooperating rovers (RWC). FIDO rover is an advanced technology prototype; its design and field testing support NASA's development of long range, in situ Mars surface science missions. Complementing this, SRR implements autonomous visual recognition, navigation, rendezvous, and manipulation functions enabling small object pick-up, handling, and precision terminal docking to a Mars ascent vehicle for future Mars Sample Return. ATE implements on-board reconfiguration of rover geometry and control for adaptive response to adverse and changing terrain, e.g., traversal of steep, sandy slopes. RWC implements coordinated control of two rovers under closed loop kinematics and force constraints, e.g., transport of large payloads, as would occur in robotic colonies at future Mars outposts. RWC is based in a new extensible architecture for decentralized control of, and collective state estimation by multiple heterogeneous robotic platforms-CAMPOUT; we overview the key architectural features. We have conducted experiments with all these new rover system concepts over variable natural terrain. For each of the above developments, we summarize our approach, some of our key experimental results to date, and our future directions of planned development. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM paul.s.schenker@jpl.nasa.gov NR 39 TC 80 Z9 87 U1 3 U2 15 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0929-5593 EI 1573-7527 J9 AUTON ROBOT JI Auton. Robot. PD MAR-MAY PY 2003 VL 14 IS 2-3 BP 103 EP 126 DI 10.1023/A:1022271301244 PG 24 WC Computer Science, Artificial Intelligence; Robotics SC Computer Science; Robotics GA 641JL UT WOS:000180741600003 ER PT J AU Elfes, A Bueno, SS Bergerman, M De Paiva, EC Ramos, JG Azinheira, JR AF Elfes, A Bueno, SS Bergerman, M De Paiva, EC Ramos, JG Azinheira, JR TI Robotic airships for exploration of planetary bodies with an atmosphere: Autonomy challenges SO AUTONOMOUS ROBOTS LA English DT Article; Proceedings Paper CT 10th International Conference on Advanced Robotics CY AUG 22-25, 2001 CL BUDAPEST, HUNGARY DE robotic airship; autonomy architectures; UAV; planetary exploration; atmospheric vehicles; aerobot; flight path control; UAV perception AB Robotic unmanned aerial vehicles have great potential as surveying and instrument deployment platforms in the exploration of planets and moons with an atmosphere. Among the various types of planetary aerovehicles proposed, lighter-than-atmosphere (LTA) systems are of particular interest because of their extended mission duration and long traverse capabilities. In this paper, we argue that the unique characteristics of robotic airships make them ideal candidates for exploration of planetary bodies with an atmosphere. Robotic airships extend the capabilities of balloons through their flight controllability, allowing (1) precise flight path execution for surveying purposes, (2) long-range as well as close-up ground observations, (3) station-keeping for long-term monitoring of high science value sites, (4) transportation and deployment of scientific instruments and in situ laboratory facilities across vast distances, and (5) opportunistic flight path replanning in response to the detection of relevant sensor signatures. Implementation of these capabilities requires achieving a high degree of vehicle autonomy across a broad spectrum of operational scenarios. The paper outlines some of the core autonomy technologies required to implement the capabilities listed above, drawing on work and results obtained in the context of AURORA (Autonomous Unmanned Remote Monitoring Robotic Airship), a research effort that focuses on the development of the technologies required for substantially autonomous robotic airships. We discuss airship modeling and control, autonomous navigation, and sensor-based flight control. We also outline an approach to airborne perception and monitoring which includes mission-specific target acquisition, discrimination and identification, and present experimental results obtained with AURORA. C1 CALTECH, Jet Prop Lab, NASA, Pasadena, CA 91109 USA. CenPRA, LRVC, Campinas, SP, Brazil. IST, IDMEC, Lisbon, Portugal. RP Elfes, A (reprint author), CALTECH, Jet Prop Lab, NASA, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Elfes, Alberto/E-2463-2011; Azinheira, Jose/I-7065-2015 OI Elfes, Alberto/0000-0003-2433-995X; Azinheira, Jose/0000-0002-0759-3211 NR 40 TC 18 Z9 20 U1 1 U2 4 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0929-5593 J9 AUTON ROBOT JI Auton. Robot. PD MAR-MAY PY 2003 VL 14 IS 2-3 BP 147 EP 164 DI 10.1023/A:1022227602153 PG 18 WC Computer Science, Artificial Intelligence; Robotics SC Computer Science; Robotics GA 641JL UT WOS:000180741600005 ER PT J AU Rodriguez, G Weisbin, CR AF Rodriguez, G Weisbin, CR TI A new method to evaluate human-robot system performance SO AUTONOMOUS ROBOTS LA English DT Article; Proceedings Paper CT 10th International Conference on Advanced Robotics CY AUG 22-25, 2001 CL BUDAPEST, HUNGARY DE robotics; human-robot systems; performance; analysis ID EARLY MARS; WARM; WET AB One of the key issues in space exploration is that of deciding what space tasks are best done with humans, with robots, or a suitable combination of each. In general, human and robot skills are complementary. Humans provide as yet unmatched capabilities to perceive, think, and act when faced with anomalies and unforeseen events, but there can be huge potential risks to human safety in getting these benefits. Robots provide complementary skills in being able to work in extremely risky environments, but their ability to perceive, think, and act by themselves is currently not error-free, although these capabilities are continually improving with the emergence of new technologies. Substantial past experience validates these generally qualitative notions. However, there is a need for more rigorously systematic evaluation of human and robot roles, in order to optimize the design and performance of human-robot system architectures using well-defined performance evaluation metrics. This article summarizes a new analytical method to conduct such quantitative evaluations. While the article focuses on evaluating human-robot systems, the method is generally applicable to a much broader class of systems whose performance needs to be evaluated. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Rodriguez, G (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM guillermo.rodriguez@jpl.nasa.gov NR 27 TC 19 Z9 19 U1 0 U2 8 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0929-5593 J9 AUTON ROBOT JI Auton. Robot. PD MAR-MAY PY 2003 VL 14 IS 2-3 BP 165 EP 178 DI 10.1023/A:1022279618991 PG 14 WC Computer Science, Artificial Intelligence; Robotics SC Computer Science; Robotics GA 641JL UT WOS:000180741600006 PM 12703512 ER PT J AU Bluethmann, W Ambrose, R Diftler, M Askew, S Huber, E Goza, M Rehnmark, F Lovchik, C Magruder, D AF Bluethmann, W Ambrose, R Diftler, M Askew, S Huber, E Goza, M Rehnmark, F Lovchik, C Magruder, D TI Robonaut: A robot designed to work with humans in space SO AUTONOMOUS ROBOTS LA English DT Article; Proceedings Paper CT 10th International Conference on Advanced Robotics CY AUG 22-25, 2001 CL BUDAPEST, HUNGARY DE Robonaut; Space Robots; dexterous robots; human-robot interaction; teleoperation; autonomous humanoid; dexterous hands; tool-using robot AB The Robotics Technology Branch at the NASA Johnson Space Center is developing robotic systems to assist astronauts in space. One such system, Robonaut, is a humanoid robot with the dexterity approaching that of a suited astronaut. Robonaut currently has two dexterous arms and hands, a three degree-of-freedom articulating waist, and a two degree-of-freedom neck used as a camera and sensor platform. In contrast to other space manipulator systems, Robonaut is designed to work within existing corridors and use the same tools as space walking astronauts. Robonaut is envisioned as working with astronauts, both autonomously and by teleoperation, performing a variety of tasks including, routine maintenance, setting up and breaking down worksites, assisting crew members while outside of spacecraft, and serving in a rapid response capacity. C1 Hernandez Engn Inc, Houston, TX 77062 USA. NASA, Lyndon B Johnson Space Ctr, Robot Technol Branch, Houston, TX 77058 USA. Lockheed Martin Corp, Automat & Robot Dept, Houston, TX 77058 USA. Metrica Inc, Texas Robot & Automat Ctr Labs, Houston, TX 77058 USA. RP Bluethmann, W (reprint author), Hernandez Engn Inc, Houston, TX 77062 USA. EM bluethmann@jsc.nasa.gov; ainbrose@jsc.nasa.gov; diftler@jsc.nasa.gov; askew@jsc.nasa.gov; eric@roboteyes.com; s.m.goza@jsc.nasa.gov; rehnmark@jsc.nasa.gov; lovchik@jsc.nasa.gov; magruder@jsc.nasa.gov NR 21 TC 79 Z9 81 U1 1 U2 12 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0929-5593 J9 AUTON ROBOT JI Auton. Robot. PD MAR-MAY PY 2003 VL 14 IS 2-3 BP 179 EP 197 DI 10.1023/A:1022231703061 PG 19 WC Computer Science, Artificial Intelligence; Robotics SC Computer Science; Robotics GA 641JL UT WOS:000180741600007 PM 12703513 ER PT J AU Kraft, NO Lyons, TJ Binder, H AF Kraft, NO Lyons, TJ Binder, H TI Group dynamics and catecholamines during long-duration confinement in an isolated environment SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article DE space-analog environment; catecholamines; confinement; group dynamics ID SPACE MISSIONS; SPACEFLIGHT AB Introduction: The objectives of this study were to investigate possible relationships between catecholamine excretion and long-duration confinement in an isolated environment. Methods: Stays of long duration were made by Group I (n = 4, all Russian, weeks 1-34), Group 11 (n = 4, mixed nationality, weeks 3-18), and Group I[] (n = 4, mixed nationality, weeks 22-38); other groups joined the residents for 1-wk intervals at weeks #13, #19, and #33. Data were collected from Groups I and Ill. Results: In both Group I and Group III, the daily epinephrine excretion was significantly elevated during and after confinement compared with the pre-isolation baseline (p < 0.05), but remained mostly within normal limits during the experiment. During isolation, epinephrine excretion was significantly higher, compared with other weeks in isolation, during weeks #19 and #27 for Group I, and during week #30 for Group III. In both Group I and Group 111, norepinephrine excretion increased significantly during and after isolation (p < 0.05) and was above the normal range. The daily norepinephrine excretion was significantly higher (p < 0.05) in Group I during weeks #12, #13, and #27, and during week #30 for Group III. Discussion: Epinephrine excretion generally remained in the normal range. However, occasional elevations occurred due to psychological stress, which apparently correlate with changes in group dynamics. Norepinephrine excretion was above the normal range and was correlated with social events. These results suggest that to ensure optimum crew performance, entire crews along with their visiting crews should be selected collectively, rather than individually. C1 NASA, Ames Res Ctr, Human Factors Res & Technol Div, Moffett Field, CA 94035 USA. Asian Off Aerosp R&D, 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 23 TC 4 Z9 4 U1 0 U2 1 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 USA SN 0095-6562 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD MAR PY 2003 VL 74 IS 3 BP 266 EP 272 PG 7 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA 652KF UT WOS:000181377800011 PM 12650275 ER PT J AU Hucka, M Finney, A Sauro, HM Bolouri, H Doyle, JC Kitano, H Arkin, AP Bornstein, BJ Bray, D Cornish-Bowden, A Cuellar, AA Dronov, S Gilles, ED Ginkel, M Gor, V Goryanin, II Hedley, WJ Hodgman, TC Hofmeyr, JH Hunter, PJ Juty, NS Kasberger, JL Kremling, A Kummer, U Le Novere, N Loew, LM Lucio, D Mendes, P Minch, E Mjolsness, ED Nakayama, Y Nelson, MR Nielsen, PF Sakurada, T Schaff, JC Shapiro, BE Shimizu, TS Spence, HD Stelling, J Takahashi, K Tomita, M Wagner, J Wang, J AF Hucka, M Finney, A Sauro, HM Bolouri, H Doyle, JC Kitano, H Arkin, AP Bornstein, BJ Bray, D Cornish-Bowden, A Cuellar, AA Dronov, S Gilles, ED Ginkel, M Gor, V Goryanin, II Hedley, WJ Hodgman, TC Hofmeyr, JH Hunter, PJ Juty, NS Kasberger, JL Kremling, A Kummer, U Le Novere, N Loew, LM Lucio, D Mendes, P Minch, E Mjolsness, ED Nakayama, Y Nelson, MR Nielsen, PF Sakurada, T Schaff, JC Shapiro, BE Shimizu, TS Spence, HD Stelling, J Takahashi, K Tomita, M Wagner, J Wang, J CA SBML Forum TI The systems biology markup language (SBML): a medium for representation and exchange of biochemical network models SO BIOINFORMATICS LA English DT Article ID PATHWAYS; SIMULATION AB Motivation: Molecular biotechnology now makes it possible to build elaborate systems models, but the systems biology community needs information standards if models are to be shared, evaluated and developed cooperatively. Results: We summarize the Systems Biology Markup Language (SBML) Level 1, a free, open, XML-based format for representing biochemical reaction networks. SBML is a software-independent language for describing models common to research in many areas of computational biology, including cell signaling pathways, metabolic pathways, gene regulation, and others. C1 CALTECH, Pasadena, CA 91125 USA. ERATO, Kitano Symbiot Syst Project, Tokyo, Japan. Univ Hertfordshire, Hatfield AL10 9AB, Herts, England. Syst Biol Inst, Tokyo, Japan. Univ Calif Berkeley, Berkeley, CA 94720 USA. NASA, JPL, Pasadena, CA USA. Univ Cambridge, Cambridge, England. CNRS, BIP, Marseille, France. Univ Auckland, Auckland 1, New Zealand. GlaxoSmithKline, Stevenage, Herts, England. Max Planck Inst Complex Tech Syst, Magdeburg, Germany. Univ Stellenbosch, ZA-7600 Stellenbosch, South Africa. EML, Heidelberg, Germany. Univ Connecticut, Ctr Hlth, Farmington, CT USA. Virginia Bioinformat Inst, Blacksburg, VA USA. Keio Univ, Tokyo, Japan. Physiome Sci Inc, Princeton, NJ USA. Sony Comp Sci Labs Inc, Tokyo, Japan. LION Biosci AG, Heidelberg, Germany. Univ Calif Irvine, Sch Informat & Comp Sci, Irvine, CA USA. RP Hucka, M (reprint author), CALTECH, MC 107-81, Pasadena, CA 91125 USA. RI Arkin, Adam/A-6751-2008; Cornish-Bowden, Athel/E-3474-2010; Le Novere, Nicolas/F-9973-2010; Hucka, Michael/B-1896-2012; Nielsen, Poul/A-5814-2009; Stelling, Joerg/F-7499-2010; OI Hodgman, Charlie/0000-0001-5862-8296; Hunter, Peter/0000-0001-9665-4145; Arkin, Adam/0000-0002-4999-2931; Le Novere, Nicolas/0000-0002-6309-7327; Nielsen, Poul/0000-0002-4704-0179; Stelling, Joerg/0000-0002-1145-891X; Sauro, Herbert/0000-0002-3659-6817; Loew, Leslie/0000-0002-1851-4646; Juty, Navtej/0000-0002-2036-8350 NR 24 TC 1413 Z9 1462 U1 7 U2 70 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 1367-4803 J9 BIOINFORMATICS JI Bioinformatics PD MAR 1 PY 2003 VL 19 IS 4 BP 524 EP 531 DI 10.1093/bioinformatics/btg015 PG 8 WC Biochemical Research Methods; Biotechnology & Applied Microbiology; Computer Science, Interdisciplinary Applications; Mathematical & Computational Biology; Statistics & Probability SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Computer Science; Mathematical & Computational Biology; Mathematics GA 652ZL UT WOS:000181410700011 PM 12611808 ER PT J AU Gerber, RB Chaban, GM Gregurick, SK Brauer, B AF Gerber, RB Chaban, GM Gregurick, SK Brauer, B TI Vibrational spectroscopy and the development of new force fields for biological molecules SO BIOPOLYMERS LA English DT Article DE vibrational spectroscopy; force fields; biological molecules; potential energy surfaces; anharmonic couplings; vibrational self-consistent field ID SELF-CONSISTENT-FIELD; DENSITY-FUNCTIONAL THEORY; AB-INITIO; EMPIRICAL POTENTIALS; POLYATOMIC-MOLECULES; N-METHYLACETAMIDE; COMBINED QUANTUM; WAVE-FUNCTIONS; STATES; GLYCINE AB The role of vibrational spectroscopy in the testing of force fields of biological molecules and in the determination of improved force fields is discussed. Analysis shows that quantitative testing of potential energy surfaces by comparison with spectroscopic data generally requires calculations that include anharmonic couplings between different vibrational modes. Applications of the vibrational self-consistent field (VSCF) method to calculations of spectroscopy of biological molecules are presented, and comparison with experiment is used to determine the merits and flaws of various types of force fields. The main conclusions include the following: (1) Potential surfaces from ab initio methods at the level of MP2 yield very satisfactory agreement with spectroscopic experimental data. (2) By the test of spectroscopy, ab initio force fields are considerably superior to the standard versions of force fields such as AMBER or OPLS. (3) Much of the spectroscopic weakness of AMBER and OPLS is due to incorrect description of anharmonic coupling, between different vibrational modes. (4) Potential surfaces of the QM/MM (Quantum Mechanics/Molecular Mechanics) type, and potentials based on improved versions of semi-empirical electronic structure theory, which are feasible for large biological molecules, yield encouraging results by the test of vibrational spectroscopy. (C) 2003 Wiley Periodicals, Inc. C1 Hebrew Univ Jerusalem, Dept Phys Chem, IL-91904 Jerusalem, Israel. Hebrew Univ Jerusalem, Fritz Haber Res Ctr, IL-91904 Jerusalem, Israel. Univ Calif Irvine, Dept Chem, Irvine, CA 92697 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Maryland Baltimore Cty, Dept Chem & Biochem, Baltimore, MD 21250 USA. RP Gerber, RB (reprint author), Hebrew Univ Jerusalem, Dept Phys Chem, IL-91904 Jerusalem, Israel. NR 53 TC 38 Z9 40 U1 0 U2 4 PU JOHN WILEY & SONS INC PI HOBOKEN PA 111 RIVER ST, HOBOKEN, NJ 07030 USA SN 0006-3525 J9 BIOPOLYMERS JI Biopolymers PD MAR PY 2003 VL 68 IS 3 BP 370 EP 382 DI 10.1002/bip.10293 PG 13 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA 652CV UT WOS:000181363000013 PM 12601796 ER PT J AU McMenamin, S Reinsch, S Conway, G AF McMenamin, S Reinsch, S Conway, G TI Direct comparison of common fixation methods for preservation of microtubules in zebrafish embryos SO BIOTECHNIQUES LA English DT Article ID ORGANIZATION; ARRAYS; GENE; CELL C1 NASA, Ames Res Ctr, Div Life Sci, Moffett Field, CA 94035 USA. Mt Holyoke Coll, S Hadley, MA 01075 USA. RP Reinsch, S (reprint author), NASA, Ames Res Ctr, Div Life Sci, MS 239-11, Moffett Field, CA 94035 USA. RI McMenamin, Sarah/A-3480-2011 NR 14 TC 4 Z9 4 U1 1 U2 2 PU EATON PUBLISHING CO PI NATICK PA 154 E. CENTRAL ST, NATICK, MA 01760 USA SN 0736-6205 J9 BIOTECHNIQUES JI Biotechniques PD MAR PY 2003 VL 34 IS 3 BP 468 EP + PG 3 WC Biochemical Research Methods; Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 654AZ UT WOS:000181471500004 PM 12661152 ER PT J AU Spina, AP AF Spina, AP TI Habitat associations of steelhead trout near the southern extent of their range SO CALIFORNIA FISH AND GAME LA English DT Article ID JUVENILE COHO SALMON; CUTTHROAT TROUT; ONCORHYNCHUS-KISUTCH; PATCHY ENVIRONMENT; CHINOOK SALMON; SMALL STREAM; WATER TEMPERATURE; CANOPY REMOVAL; RAINBOW-TROUT; SELECTION AB Habitat associations of wild steel head trout, Oncorhynchus mykiss, in southern and south-central California are poorly described in the scientific literature and are largely unknown. Descriptive surveys and a manipulative experiment were performed to assess use of depth,velocity, run and pool by wild age-0, age-1 and age-2 steelhead in a small south-central California stream. Juvenile steelhead showed size-specific use of depth and velocity, though water depth was the better predictor of size-specific microhabitat use. Age-0 steelhead used shallow areas of the stream, whereas age-1 and age-2 steelhead used relatively deep areas. Juvenile steelhead used pools and runs, but age-0 steelhead showed greater occupancy of runs than was expected when abundance was adjusted according to the size of the sampled unit. Spatial variation in the density of juvenile steelhead was related to the water depth and size of the sampled units and the amount of riparian canopy cover. Because the habitats used by age-0 steelhead may not be suitable for age-1 and older steelhead, the results suggest that multiyear freshwater residence of steelhead requires habitat that is appropriate for all age classes. C1 Natl Marine Fisheries Serv, Long Beach, CA 90802 USA. RP Spina, AP (reprint author), Natl Marine Fisheries Serv, 501 W Ocean Blvd,Suite 4200, Long Beach, CA 90802 USA. EM anthony.spina@noaa.gov NR 51 TC 3 Z9 3 U1 1 U2 9 PU CALIFORNIA FISH AND GAME EDITOR PI SACRAMENTO PA 1416 NINTH ST, SACRAMENTO, CA 95814 USA SN 0008-1078 J9 CALIF FISH GAME JI Calif. Fish Game PD SPR PY 2003 VL 89 IS 2 BP 81 EP 95 PG 15 WC Fisheries; Zoology SC Fisheries; Zoology GA 710UH UT WOS:000184699800003 ER PT J AU Jenkins, GS Mikovitz, JC AF Jenkins, GS Mikovitz, JC TI Examining climate variability over West Africa during the 1979-1993 period: observations and CCM3 comparisons SO CLIMATE DYNAMICS LA English DT Article ID SEA-SURFACE TEMPERATURE; WAVE DISTURBANCES; TROPICAL ATLANTIC; INTERANNUAL VARIABILITY; GLOBAL PRECIPITATION; SPATIAL VARIABILITY; EASTERLY WAVES; SAHEL RAINFALL; NORTH-AFRICA; MODEL AB The Community Climate Model Version 3.6 is used to simulate the mean climate of West Africa during the Northern Hemisphere summer season (June-August). The climate model uses prescribed climatological sea surface temperatures (SSTs) and observed SSTs during the 1979-1993 period. Two important circulation features, the African Easterly Jet (AEJ) and the Tropical Easterly Jet (TEJ), are found in the simulations but a westerly wind bias is found with respect to 700 hPa winds. Consequently, easterly waves and rain rates are poorly simulated. The primary cause of the poorly simulated AEJ is the advection of cold air from Europe producing a cold bias over northern Africa and a weaker than observed meridional temperature gradient. The cold bias is caused by an eastward displacement of the simulated Azores surface high into Western Europe creating a stronger than observed meridional sea level pressure gradient over northern Africa. This bias systematically occurs in simulations using both climatological and observed SSTs. The biases in sea level pressure, temperature and zonal winds have the potential to produce poor regional climate model results for West Africa if the meteorological output from the CCM3 is used as lateral boundaries. Moreover, these biases introduce uncertainties to West African GCM sensitivity studies associated with interannual variability, land-use change and elevated anthropogenic greenhouse gases. C1 Penn State Univ, Dept Meteorol, University Pk, PA 16802 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Jenkins, GS (reprint author), Penn State Univ, Dept Meteorol, 503 Walker Bldg, University Pk, PA 16802 USA. NR 43 TC 4 Z9 4 U1 0 U2 1 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0930-7575 J9 CLIM DYNAM JI Clim. Dyn. PD MAR PY 2003 VL 20 IS 5 BP 503 EP 522 DI 10.1007/s00382-002-0287-z PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 671UN UT WOS:000182482600006 ER PT J AU Reilly, J Tubiello, F McCarl, B Abler, D Darwin, R Fuglie, K Hollinger, S Izaurralde, C Jagtap, S Jones, J Mearns, L Ojima, D Paul, E Paustian, K Riha, S Rosenberg, N Rosenzweig, C AF Reilly, J Tubiello, F McCarl, B Abler, D Darwin, R Fuglie, K Hollinger, S Izaurralde, C Jagtap, S Jones, J Mearns, L Ojima, D Paul, E Paustian, K Riha, S Rosenberg, N Rosenzweig, C TI US agriculture and climate change: New results SO CLIMATIC CHANGE LA English DT Article ID UNITED-STATES; ADAPTATION; FREQUENCY; VARIABILITY; TEMPERATURE; IMPACTS; EVENTS; TRENDS; SECTOR AB We examined the impacts on U.S. agriculture of transient climate change as simulated by 2 global general circulation models focusing on the decades of the 2030s and 2090s. We examined historical shifts in the location of crops and trends in the variability of U.S. average crop yields, finding that non-climatic forces have likely dominated the north and westward movement of crops and the trends in yield variability. For the simulated future climates we considered impacts on crops, grazing and pasture, livestock, pesticide use, irrigation water supply and demand, and the sensitivity to international trade assumptions, finding that the aggregate of these effects were positive for the U.S. consumer but negative, due to declining crop prices, for producers. We examined the effects of potential changes in El Nino/Southern Oscillation (ENSO) and impacts on yield variability of changes in mean climate conditions. Increased losses occurred with ENSO intensity and frequency increases that could not be completely offset even if the events could be perfectly forecasted. Effects on yield variability of changes in mean temperatures were mixed. We also considered case study interactions of climate, agriculture, and the environment focusing on climate effects on nutrient loading to the Chesapeake Bay and groundwater depletion of the Edward's Aquifer that provides water for municipalities and agriculture to the San Antonio, Texas area. While only case studies, these results suggest environmental targets such as pumping limits and changes in farm practices to limit nutrient run-off Would need to be tightened if current environmental goals were to be achieved under the climate scenarios we examined. C1 MIT, Cambridge, MA 02139 USA. Goddard Inst Space Studies, New York, NY USA. Texas A&M Univ, College Stn, TX 77843 USA. Penn State Univ, University Pk, PA 16802 USA. USDA, Washington, DC 20250 USA. Illinois State Water Survey, Champaign, IL 61820 USA. Pacific NW Natl Lab, Richland, WA USA. Univ Florida, Gainesville, FL USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. Colorado State Univ, Ft Collins, CO 80523 USA. Michigan State Univ, E Lansing, MI 48824 USA. Cornell Univ, Ithaca, NY 14853 USA. RP Reilly, J (reprint author), MIT, 77 Massachusetts Ave,E40-269, Cambridge, MA 02139 USA. RI McCarl, Bruce/E-9445-2011; Izaurralde, Roberto/E-5826-2012; Ojima, Dennis/C-5272-2016; Paustian, Keith/L-7593-2016 NR 50 TC 127 Z9 139 U1 6 U2 70 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0165-0009 J9 CLIMATIC CHANGE JI Clim. Change PD MAR PY 2003 VL 57 IS 1-2 BP 43 EP 69 DI 10.1023/A:1022103315424 PG 27 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 651UJ UT WOS:000181340200004 ER PT J AU Lam, SH Bellan, J AF Lam, SH Bellan, J TI On de-coupling of Shvab-Zel'dovich variables in the presence of diffusion SO COMBUSTION AND FLAME LA English DT Article DE Shvab-Zeldovich variables; Lewis numbers ID LEWIS NUMBERS; KINETICS; FLAMES AB In multi-component reacting flows, it is well-known that significant simplifications are available when the "all-Lewis-numbers-are-unity" assumption can be justified. Under this assumption, certain linear combinations of the dependent variables, commonly known as the Shvab-Zel'dovich (SZ) variables, are "decoupled" from the chemistry terms. A derivation is presented here showing that the same simplifications can be achieved under less-restrictive conditions. The means to check whether these conditions are satisfied is provided. 0 2003 The Combustion Institute. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Princeton Univ, Dept Aeronaut & Mech Engn, Princeton, NJ USA. RP Bellan, J (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 14 TC 7 Z9 7 U1 0 U2 4 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0010-2180 J9 COMBUST FLAME JI Combust. Flame PD MAR PY 2003 VL 132 IS 4 BP 691 EP 696 DI 10.1016/S0010-2180(02)00519-9 PG 6 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA 671FL UT WOS:000182454600008 ER PT J AU Lathouwers, D Bellan, J AF Lathouwers, D Bellan, J TI A posteriori assessment of assumptions used in the modeling of dense reactive granular flows (vol 131, pg 353, 2002) SO COMBUSTION AND FLAME LA English DT Correction C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Delft Univ Technol, Interfac Reactor Inst, Delft, Netherlands. RP Bellan, J (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0010-2180 J9 COMBUST FLAME JI Combust. Flame PD MAR PY 2003 VL 132 IS 4 BP 755 EP 755 DI 10.1016/S0010-2180(03)00015-4 PG 1 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA 671FL UT WOS:000182454600014 ER PT J AU Elfouhaily, T Joelson, M Guignard, S Branger, H Thompson, DR Chapron, B Vandemark, D AF Elfouhaily, T Joelson, M Guignard, S Branger, H Thompson, DR Chapron, B Vandemark, D TI Analysis of random nonlinear water waves: the Stokes-Woodward technique SO COMPTES RENDUS MECANIQUE LA English DT Article DE fluid mechanics; mode coupling; wave-wave interaction; horizontal asymmetry; vertical asymmetry; bispectrum; amplitude modulation; frequency modulation ID ELECTROMAGNETIC BIAS THEORY; OCEAN WAVES AB A generalization of the Woodward's theorem is applied to the case of random signals jointly modulated in amplitude and frequency. This yields the signal spectrum and a rather robust estimate of the bispectrum. Furthermore, higher order statistics that quantify the amount of energy in the signal due to nonlinearities, e.g., wave-wave interaction in the case of water waves, can be inferred. Considering laboratory wind generated water waves, comparisons between the presented generalization and more standard techniques allow to extract the spectral energy due to nonlinear wave-wave interactions. It is shown that our analysis extends the domain of standard spectral estimation techniques from narrow-band to broad-band processes. C1 CNRS, Inst Rech Phenomenes Hors Equilibre, Marseille, France. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. IFREMER, Ctr Brest, Dept Oceanog Spatiale, F-29280 Plouzane, France. NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Wallops Isl, VA 23337 USA. RP Elfouhaily, T (reprint author), CNRS, Inst Rech Phenomenes Hors Equilibre, Marseille, France. RI Chapron, Bertrand/O-6527-2015; Branger, Hubert/E-1879-2016 OI Branger, Hubert/0000-0002-9888-681X NR 19 TC 2 Z9 2 U1 1 U2 1 PU EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER PI PARIS CEDEX 15 PA 23 RUE LINOIS, 75724 PARIS CEDEX 15, FRANCE SN 1631-0721 J9 CR MECANIQUE JI C. R. Mec. PD MAR PY 2003 VL 331 IS 3 BP 189 EP 196 DI 10.1016/S1631-0721(03)00055-X PG 8 WC Mechanics SC Mechanics GA 671NN UT WOS:000182471100002 ER PT J AU Akyildiz, IF Anjali, T Chen, L de Oliveira, JC Scoglio, C Sciuto, A Smith, JA Uhl, G AF Akyildiz, IF Anjali, T Chen, L de Oliveira, JC Scoglio, C Sciuto, A Smith, JA Uhl, G TI A new traffic engineering manager for DiffServ/MPLS networks: design and implementation on an IP QoS Testbed SO COMPUTER COMMUNICATIONS LA English DT Article; Proceedings Paper CT 2nd International Workshop on Quality of Future Internet Services CY SEP 24-26, 2001 CL COIMBRA, PORTUGAL DE DiffServ; MultiProtocol Label Switching; Traffic Engineering; Automated Network Management; Testbed ID VBR VIDEO AB In a multi-service network, different applications have varying QoS requirements. The IETF has proposed the DiffServ architecture as a scalable solution to provide Quality of Service (QoS) in IP Networks. In order to provide quantitative guarantees and optimization of transmission resources, DiffServ mechanisms should be complemented with efficient traffic engineering (TE) mechanisms, which operate on an aggregate basis across all classes of service. The MultiProtocol Label Switching (MPLS) technology is a suitable method to provide TE, independent of the underlying layer2 technology. Currently, the combined use of Differentiated Services (DiffServ) and MPLS is a promising technique to provide Quality of Service (QoS), while efficiently exploiting network resources. In this paper, TEAM, an automated manager for DiffServ/MPLS networks is introduced and its design. The design and implementation details are discussed. (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. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Georgia Inst Technol, Sch Elect & Comp Engn, Broadband & Wireless Networking Lab, Atlanta, GA 30332 USA. EM ian@ece.gatech.edu; tricha@ece.gatech.edu; leochen@ece.gatech.edu; jau@ece.gatech.edu; caterina@ece.gatech.edu; asciuto@rattler-e.gsfc.nasa.gov; jsmith@rattler-e.gsfc.nasa.gov; uhl@rattler-e.gsfc.nasa.gov RI Akyildiz, Ian/G-7136-2011 OI Akyildiz, Ian/0000-0002-8099-3529 NR 55 TC 10 Z9 12 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0140-3664 EI 1873-703X J9 COMPUT COMMUN JI Comput. Commun. PD MAR 1 PY 2003 VL 26 IS 4 BP 388 EP 403 AR PII S0140-3664(02)00157-3 DI 10.1016/S0140-3664(02)00157-3 PG 16 WC Computer Science, Information Systems; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA 649XX UT WOS:000181234200010 ER PT J AU Bartels, RE AF Bartels, RE TI A time integration algorithm based on the state transition matrix for structures with time varying and nonlinear properties SO COMPUTERS & STRUCTURES LA English DT Article DE computational algorithm; linear; time variant; nonlinear; state transition matrix; structural dynamics; chaos ID OSCILLATORS AB A variable order method of integrating the structural dynamics equations that is based on the state transition matrix has been developed. The method has been evaluated for linear time variant and nonlinear systems of equations. When the time variation of the system can be modeled exactly by a polynomial it produces nearly exact solutions for a wide range of time step sizes. Solutions of a model nonlinear dynamic response exhibiting chaotic behavior have been computed. Accuracy of the method has been demonstrated by comparison with solutions obtained by established methods. Published by Elsevier Science Ltd. C1 NASA, Langley Res Ctr, Aeroelast Branch, Hampton, VA 23681 USA. RP Bartels, RE (reprint author), NASA, Langley Res Ctr, Aeroelast Branch, Mail Stop 340, Hampton, VA 23681 USA. NR 4 TC 7 Z9 8 U1 0 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0045-7949 J9 COMPUT STRUCT JI Comput. Struct. PD MAR PY 2003 VL 81 IS 6 BP 349 EP 357 DI 10.1016/S0045-7949(03)00018-X PG 9 WC Computer Science, Interdisciplinary Applications; Engineering, Civil SC Computer Science; Engineering GA 661CE UT WOS:000181873000002 ER PT J AU Yang, RX Kafatos, M Doty, B Kinter, JL Pham, L AF Yang, RX Kafatos, M Doty, B Kinter, JL Pham, L TI A distributed enhanced server for multidimensional scientific data SO COMPUTING IN SCIENCE & ENGINEERING LA English DT Article AB Faced with large and growing data sets from diverse sources (including general-purpose search engines that provide unwieldy results), the authors combine metadata search and data access concepts to create a prototype enhanced server tuned to scientific data search and accessibility. C1 George Mason Univ, Sch Computat Sci, Ctr Earth Observing & Space Res, Fairfax, VA 22030 USA. Ctr Ocean Land Atmosphere Studies, Beltsville, MD 20705 USA. NASA, Goddard Space Flight Ctr, Data Act Arch Ctr, Greenbelt, MD 20771 USA. RP George Mason Univ, Sch Computat Sci, Ctr Earth Observing & Space Res, MS 5C3, Fairfax, VA 22030 USA. EM ryang@gmu.edu; mkafatos@gmu.edu; doty@cola.iges.org; kinter@cola.iges.org; long.b.pham@nasa.gov NR 10 TC 0 Z9 0 U1 1 U2 2 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 1521-9615 EI 1558-366X J9 COMPUT SCI ENG JI Comput. Sci. Eng. PD MAR-APR PY 2003 VL 5 IS 2 BP 44 EP 52 DI 10.1109/MCISE.2003.1182961 PG 9 WC Computer Science, Interdisciplinary Applications SC Computer Science GA 653MR UT WOS:000181440800009 ER PT J AU Riley, CJ Chatterjee, S Biswas, R AF Riley, CJ Chatterjee, S Biswas, R TI High-performance Java codes for computational fluid dynamics SO CONCURRENCY AND COMPUTATION-PRACTICE & EXPERIENCE LA English DT Article; Proceedings Paper CT ACM 2001 Java Grande/International Symposium on Computing in Object-Oriented Parallel Environments CY JUN 02-04, 2001 CL STANFORD UNIV, STANFORD, CA HO STANFORD UNIV DE scientific computing; object-oriented; benchmarks ID SCHEMES AB The computational science community is reluctant to write large-scale computationally-intensive applications in Java due to concerns over Java's poor performance, despite the claimed software engineering advantages of its object-oriented features. Naive Java implementations of numerical algorithms can perform poorly compared to corresponding Fortran or C implementations. To achieve high performance, Java applications must be designed with good performance as a primary goal. This paper presents the object-oriented design and implementation of two real-world applications from the field of computational fluid dynamics (CFD): a finite-volume fluid flow solver (LAURA, from NASA Langley Research Center) and an unstructured mesh adaptation algorithm (2D_TAG, from NASA Ames Research Center). This work builds on our previous experience with the design of high-performance numerical libraries in Java. We examine the performance of the applications using the currently available Java infrastructure and show that the Java version of the flow solver LAURA performs almost within a factor of 2 of the original procedural version. Our Java version of the mesh adaptation algorithm 2D-TAG performs within a factor of 1.5 of its original procedural version on certain platforms. Our results demonstrate that object-oriented software design principles are not necessarily inimical to high performance. Copyright (C) 2003 John Wiley Sons, Ltd. C1 Blue Ridge Numer Inc, Charlottesville, VA 22901 USA. IBM Corp, Thomas J Watson Res Ctr, Yorktown Hts, NY 10598 USA. NASA, Adv Supercomp Div, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Blue Ridge Numer Inc, Charlottesville, VA 22901 USA. EM chris.riley@cfdesign.com NR 32 TC 9 Z9 9 U1 0 U2 1 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 1532-0626 EI 1532-0634 J9 CONCURR COMP-PRACT E JI Concurr. Comput.-Pract. Exp. PD MAR-APR PY 2003 VL 15 IS 3-5 BP 395 EP 415 DI 10.1002/cpe.656 PG 21 WC Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA 652CF UT WOS:000181361400011 ER PT J AU Ferree, DS van der Woerd, MJ AF Ferree, DS van der Woerd, MJ TI A brief analysis of capillary sealing methods and their effectiveness SO CRYSTAL GROWTH & DESIGN LA English DT Article ID CRYSTALLIZATION; CRYOCRYSTALLOGRAPHY; PROTEIN AB Protein crystals and the solutions from which they are grown must be carefully protected against dehydration. In the absence of a proper seal, the crystals will dehydrate and lose their original properties and subsequently the ability to diffract X-rays. We conducted a systematic study of the efficacy of the most common sealing materials in use and we report the results here. The study shows that no single material is completely effective in both untreated and silanized glass capillaries. Various combinations of two materials, however, give excellent seals that will prevent dehydration for long periods of time. Recommendations are made for sealing materials to be used. C1 NASA, Univ Space Res Assoc, Struct Biol Lab, MSFC, Huntsville, AL 35812 USA. RP Ferree, DS (reprint author), NASA, Univ Space Res Assoc, Struct Biol Lab, MSFC, Code SD46, Huntsville, AL 35812 USA. NR 9 TC 1 Z9 1 U1 0 U2 1 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 MAR-APR PY 2003 VL 3 IS 2 BP 193 EP 196 DI 10.1021/cg025605g PG 4 WC Chemistry, Multidisciplinary; Crystallography; Materials Science, Multidisciplinary SC Chemistry; Crystallography; Materials Science GA 653HQ UT WOS:000181429500011 ER PT J AU Johnson, SW Murphy, ML Csepp, DJ AF Johnson, SW Murphy, ML Csepp, DJ TI Distribution, habitat, and behavior of rockfishes, Sebastes spp., in nearshore waters of southeastern Alaska: observations from a remotely operated vehicle SO ENVIRONMENTAL BIOLOGY OF FISHES LA English DT Article DE ROV; substrate; depth; temperature; species associations ID BRITISH-COLUMBIA; GENUS SEBASTES; PISCES-IV; JUVENILES; ASSOCIATIONS; ECOLOGY; EXAMPLE; FISHES; LARVAE; OREGON AB We examined distribution, habitat, and behavior of rockfishes, Sebastes spp., with a remotely operated vehicle (ROV) in coastal waters < 90 m deep of southeastern Alaska from 1998 to 2000. We identified black, S. melanops, canary, S. pinniger, China, S. nebulosus, copper, S. caurinus, dusky, S. ciliatus, harlequin, S. variegatus, Puget Sound, S. emphaeus, quillback, S. maliger, redstripe, S. proriger, rosethorn, S. helvomaculatus, silvergray, S. brevispinis, tiger, S. nigrocinctus, yelloweye, S. ruberrimus, and yellowtail, S. flavidus, rockfish. Quillback and dusky rockfish were the most widely distributed species, China and harlequin rockfish were the least widely distributed species. Species richness was greater at sites on or near the outer coast than at sites in more inside, sheltered waters. Most (> 75%) observations of rockfish were over complex bottoms of boulder and rock or in vertical bedrock wall habitats. Few rockfish were observed over soft bottoms with no relief. Median depth of observation was less than or equal to 30 m for black, copper, dusky, and yellowtail rockfish and > 30 m for all other species. Median temperature of observation ranged from 6.1 degreesC for harlequin rockfish to 9.4 degreesC for black rockfish. Size of fish was positively correlated (p less than or equal to 0.036) with depth for dusky, quillback, and yelloweye rockfish. Species often observed alone were China (67%), copper (46%), quillback (46%), and rosethorn (43%) rockfish. Most (greater than or equal to70%) observations of harlequin, Puget Sound, silvergray, tiger, and yelloweye rockfish were in mixed species assemblages. When first observed, the behavior of most rockfish species was swimming or hovering. Notable exceptions were China, harlequin, rosethorn, and tiger rockfish; 33 - 57% were resting on bottom or in a hole or crevice. C1 Natl Marine Fisheries Serv, Auke Bay Lab, Juneau, AK 99801 USA. RP Johnson, SW (reprint author), Natl Marine Fisheries Serv, Auke Bay Lab, 11305 Glacier Hwy, Juneau, AK 99801 USA. NR 37 TC 26 Z9 28 U1 2 U2 23 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0378-1909 J9 ENVIRON BIOL FISH JI Environ. Biol. Fishes PD MAR PY 2003 VL 66 IS 3 BP 259 EP 270 DI 10.1023/A:1023981908146 PG 12 WC Ecology; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA 682UF UT WOS:000183110200006 ER PT J AU Hopkins, WA Tatara, CP Brant, HA Jagoe, CH AF Hopkins, WA Tatara, CP Brant, HA Jagoe, CH TI Relationships between mercury body concentrations, standard metabolic rate, and body mass in eastern mosquitofish (Gambusia holbrooki) from three experimental populations SO ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY LA English DT Article DE mercury; mosquitofish; respiration; standard metabolic rate; tolerance ID TROUT ONCORHYNCHUS-MYKISS; DEMOGRAPHIC RESPONSES; FISH; GENERATIONS; MORPHOLOGY; TOXICITY; COSTS; LAKE AB Eastern mosquitofish (Gambusia holbrooki) were sampled from three experimental populations (two Hg-exposed populations and one reference population) to determine whether transgenerational exposure (lifelong exposure of multiple generations) to Hg adversely affects standard metabolic rate (SMR). Mosquitofish subjected to lifelong Hg exposure accumulated significant concentrations of Hg in their tissues compared to fish from the reference population (mean: 3.89-4.13 vs 0.08 muHg/g wet mass, respectively). Less than 10% of the variability in Hg tissue concentrations could be explained by fish body mass, likely because of the short life span and/or dietary habits of this species. Despite the high body burdens of Hg in exposed fish, we found no significant difference in SMR among individuals from Hg-exposed or reference populations. Our findings contrast recent laboratory work describing elevated SMR in mosquitofish exposed to 100 mug/L dissolved inorganic Hg for 48 h. To account for contrasting results between studies, we hypothesize that acute exposure to dissolved inorganic Hg damages gill epithelium, resulting in increased metabolic rate, but that lifelong Hg exposure via trophic uptake of methyl mercury does not affect fish respiratory structures. Alternative hypotheses include the possibility that G. holbrooki is a species that can tolerate high body burdens of Hg or that more than four years of genetic isolation during Hg exposure (8-12 generations) resulted in selection for Hg-tolerant or -resistant individuals. C1 Univ Georgia, Savannah River Ecol Lab, Aiken, SC 29802 USA. NW Fisheries Sci Ctr, Natl Marine Fisheries Serv, Manchester, WA 98353 USA. RP Hopkins, WA (reprint author), Univ Georgia, Savannah River Ecol Lab, Drawer E, Aiken, SC 29802 USA. NR 29 TC 15 Z9 16 U1 3 U2 11 PU SETAC PI PENSACOLA PA 1010 NORTH 12TH AVE, PENSACOLA, FL 32501-3367 USA SN 0730-7268 J9 ENVIRON TOXICOL CHEM JI Environ. Toxicol. Chem. PD MAR PY 2003 VL 22 IS 3 BP 586 EP 590 DI 10.1897/1551-5028(2003)022<0586:RBMBCS>2.0.CO;2 PG 5 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA 647JE UT WOS:000181089000017 PM 12627646 ER PT J AU Yurtsever, U Strekalov, D Dowling, JP AF Yurtsever, U Strekalov, D Dowling, JP TI Interferometry with entangled atoms SO EUROPEAN PHYSICAL JOURNAL D LA English DT Article ID WAVE INTERFEROMETRY; QUANTUM; STATES; NOISE AB A quantum gravity-gradiometer consists of two spatially separated ensembles of atoms interrogated by pulses of a common laser beam. The laser pulses cause the probability amplitudes of atomic ground-state hyperfine levels to interfere, producing two, motion-sensitive, phase shifts, which allow the measurement of the average acceleration of each ensemble, and, via simple differencing; of the acceleration gradient. Here we propose entangling the quantum states of atoms from the two ensembles prior to the pulse sequence, and show that entanglement encodes their relative acceleration in a single interference phase which can be measured directly, with no need for differencing. C1 CALTECH, Jet Prop Lab, Quantum Comp Technol Grp, Sec 367, Pasadena, CA 91109 USA. RP Yurtsever, U (reprint author), CALTECH, Jet Prop Lab, Quantum Comp Technol Grp, Sec 367, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI DOWLING, JONATHAN/L-2749-2013 NR 14 TC 2 Z9 3 U1 0 U2 2 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 1434-6060 J9 EUR PHYS J D JI Eur. Phys. J. D PD MAR PY 2003 VL 22 IS 3 BP 365 EP 371 DI 10.1140/epjd/e2003-00016-x PG 7 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 663QV UT WOS:000182017000008 ER PT J AU Liu, HS Kolenkiewicz, R Wade, C AF Liu, HS Kolenkiewicz, R Wade, C TI Orbital noise of the Earth causes intensity fluctuation in the geomagnetic field SO FLUCTUATION AND NOISE LETTERS LA English DT Article DE orbital signal; frequency noise; geomagnetic intensity fluctuations; celestial mechanics; coremantle system ID INCOMING SOLAR-RADIATION; CONDUCTING INNER-CORE; RELATIVE PALEOINTENSITY; MAGNETIC-FIELD; BRUNHES-CHRON; GEODYNAMO; DYNAMO; MODULATION; GENERATION; PRECESSION AB Orbital noise of Earth's obliquity can provide an insight into the core of the Earth that causes intensity fluctuations in the geomagnetic field. Here we show that noise spectrum of the obliquity frequency have revealed a series of frequency periods centered at 250, 100, 50, 41-, 30, and 26-kyr which are almost identical with the observed spectral peaks from the composite curve of 33 records of relative paleointensity spanning the past 800 kyr (Sint 800 data). A continuous record for the past two million years also reveals the presence of the major 100 kyr periodicity in obliquity noise and geomagnetic intensity fluctuations. These results of correlation suggest that obliquity noise may power the dynamo, located in the liquid outer core of the Earth, which generates the geomagnetic field. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Liu, HS (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM Han-Shou.Liu-1@nasa.gov NR 35 TC 2 Z9 2 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0219-4775 J9 FLUCT NOISE LETT JI Fluct. Noise Lett. PD MAR PY 2003 VL 3 IS 1 BP L63 EP L72 DI 10.1142/S0219477503001099 PG 10 WC Mathematics, Interdisciplinary Applications; Physics, Applied SC Mathematics; Physics GA 802KP UT WOS:000220162700006 ER PT J AU Lanyi, G AF Lanyi, G TI Thermal equilibrium between radiation and matter SO FOUNDATIONS OF PHYSICS LA English DT Article DE thermal; quantum; radiation; Boltzmann; Einstein; Planck AB In 1916, Einstein rederived the blackbody radiation law of Planck that originated the idea of quantized energy one hundred years ago. For this purpose, Einstein introduced the concept of transition probability, which had a profound influence on the development of quantum theory. In this article, we adopt Einstein's assumptions with two exceptions and seek the statistical condition for the thermal equilibrium of matter without referring to the inner details of either statistical thermodynamics or quantum theory. It is shown that the conditions of thermodynamic equilibrium of electromagnetic radiation and the energy balance of thermal radiation by the matter, between any of its two energy-states, not only result in Planck's radiation law and the Bohr frequency condition, but they remarkably yield the law of the statistical thermal equilibrium of matter: the Maxwell-Boltzmann distribution. Since the transition probabilities of the modern quantum theory of radiation coincide with their definition in Einstein's theory of blackbody radiation, the presented deduction of the Maxwell-Boltzmann distribution is equally valid within the bounds of modern quantum theory. Consequently, within the framework of the fundamental assumptions, the Maxwell-Boltzmann distribution of energy-states is not only a sufficient, but a necessary condition for thermal equilibrium between the matter and radiation. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lanyi, G (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 18 TC 1 Z9 1 U1 0 U2 0 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0015-9018 J9 FOUND PHYS JI Found. Phys. PD MAR PY 2003 VL 33 IS 3 BP 511 EP 528 DI 10.1023/A:1023719800307 PG 18 WC Physics, Multidisciplinary SC Physics GA 679LX UT WOS:000182924900006 ER PT J AU Krasinski, A Behr, CG Schucking, E Estabrook, FB Wahlquist, HD Ellis, GFR Jantzen, R Kundt, W AF Krasinski, A Behr, CG Schucking, E Estabrook, FB Wahlquist, HD Ellis, GFR Jantzen, R Kundt, W TI The Bianchi classification in the Schucking-Behr approach SO GENERAL RELATIVITY AND GRAVITATION LA English DT Article DE Bianchi models; Lie algebra; cosmology.3 AB The historical development of the Bianchi classification of homogeneous cosmological models is described with special emphasis on the contributions by Schucking and Behr. C1 Polish Acad Sci, Copernicus Astron Ctr, Warsaw, Poland. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Cape Town, Dept Math, ZA-7700 Rondebosch, South Africa. Villanova Univ, Dept Math Sci, Villanova, PA 19085 USA. Univ Bonn, Inst Astrophys, D-53121 Bonn, Germany. RP Krasinski, A (reprint author), Polish Acad Sci, Copernicus Astron Ctr, Warsaw, Poland. NR 33 TC 15 Z9 15 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 MAR PY 2003 VL 35 IS 3 BP 475 EP 489 DI 10.1023/A:1022382202778 PG 15 WC Astronomy & Astrophysics; Physics, Multidisciplinary; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 645ZJ UT WOS:000181010100012 ER PT J AU Drake, JB Knox, RG Dubayah, RO Clark, DB Condit, R Blair, JB Hofton, M AF Drake, JB Knox, RG Dubayah, RO Clark, DB Condit, R Blair, JB Hofton, M TI Above-ground biomass estimation in closed canopy Neotropical forests using lidar remote sensing: factors affecting the generality of relationships SO GLOBAL ECOLOGY AND BIOGEOGRAPHY LA English DT Article DE above-ground biomass; allometry; carbon cycle; Central America; environmental factors; forest structure; laser altimetry; lidar; remote sensing; tropical forests ID LARGE-FOOTPRINT LIDAR; TROPICAL RAIN-FOREST; LASER ALTIMETER; HEIGHT PROFILES; LANDSCAPE-SCALE; BIOSPHERE MODEL; COSTA-RICA; VEGETATION; SECONDARY; BRAZIL AB Aim Previous studies have developed strong, site-specific relationships between canopy metrics from lidar (light detecting and ranging) remote sensing data and forest structural characteristics such as above-ground biomass (AGBM), but the generality of these relationships is unknown. In this study, we examine the generality of relationships between lidar metrics and forest structural characteristics, including AGBM, from two study areas in Central America with different precipitation patterns. Location A series of tropical moist forest sites in Panama and a tropical wet forest in Costa Rica. Methods Canopy metrics (e.g. canopy height) were calculated from airborne lidar data. Basal area, mean stem diameter and AGBM were calculated from measurements taken as a part of ongoing forest dynamics studies in both areas. We examined the generality of relationship between lidar metrics and forest structure, and possible environmental effects (e.g. leaf phenology). Results We found that lidar metrics were strongly correlated (R-2:0.65-0.92) with mean stem diameter, basal area and AGBM in both regions. We also show that the relationships differed between these regions. Deciduousness of canopy trees in the tropical moist forest area accounted for the differences in predictive equations for stem diameter and basal area. The relationships between lidar metrics and AGBM, however, remained significantly different between the two study areas even after adjusting for leaf drop. We attribute this to significant differences in the underlying allometric relationships between stem diameter and AGBM in tropical wet and moist forests. Conclusions Important forest structural characteristics can be estimated reliably across a variety of conditions sampled in these closed-canopy tropical forests. Environmental factors such as drought deciduousness have an important influence on these relationships. Future efforts should continue to examine climatic factors that may influence the generality of the relationships between lidar metrics and forest structural characteristics and assess more rigorously the generality of field-derived allometric relationships. C1 Univ Maryland, Dept Geog, College Pk, MD 20742 USA. NASA, Biospher Sci Branch, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Missouri, Dept Biol, St Louis, MO 63121 USA. Smithsonian Trop Res Inst, Ctr Trop Forest Sci, Unit 0948, APO, AA 34002 USA. NASA, Laser Remote Sensing Branch, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Drake, JB (reprint author), Univ Georgia, Warnell Sch Forest Resources, Athens, GA 30602 USA. RI Knox, Robert/E-9657-2011; Blair, James/D-3881-2013; Beckley, Matthew/D-4547-2013 NR 58 TC 146 Z9 149 U1 5 U2 63 PU BLACKWELL PUBLISHING LTD PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DG, OXON, ENGLAND SN 0960-7447 J9 GLOBAL ECOL BIOGEOGR JI Glob. Ecol. Biogeogr. PD MAR PY 2003 VL 12 IS 2 BP 147 EP 159 DI 10.1046/j.1466-822X.2003.00010.x PG 13 WC Ecology; Geography, Physical SC Environmental Sciences & Ecology; Physical Geography GA 652TU UT WOS:000181396700006 ER PT J AU Hergenrother, PM AF Hergenrother, PM TI The use, design, synthesis, and properties of high performance/high temperature polymers: an overview SO HIGH PERFORMANCE POLYMERS LA English DT Review DE high temperature/high performance polymers; polyimides; polyarylene ethers; phenylethynyl-terminated oligomers; chemical structure/property relationships ID POLYIMIDES; PHENYLETHYNYL; OLIGOMERS; DIAMINES; DIANHYDRIDES; SULFONE)S AB An overview of the definition and development of, factors that contribute to, applications and markets for and the design of high performance/high temperature polymers is presented. Of the many families of high performance/high temperature polymers known, the most popular families consisting of polyimides, polyarylene ethers and phenylethynyl-terminated oligomers are used to demonstrate the basic principles in polymer development. Chemical structure/property relationships are used to show how polymers can be designed with a unique combination of properties. The estimated worldwide market for high temperature polymers in 2000 was 206,700,000 kgs constituting $4.36B with polyimides comprising 3,982,000 kgs or $1.07B (24% of the dollar value). With an improvement in the world economy, this market is predicted to grow substantially. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Hergenrother, PM (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 85 TC 237 Z9 264 U1 3 U2 44 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 MAR PY 2003 VL 15 IS 1 BP 3 EP 45 PG 43 WC Polymer Science SC Polymer Science GA 674VY UT WOS:000182658600001 ER PT J AU Hendrix, AR Vilas, F Festou, MC AF Hendrix, AR Vilas, F Festou, MC TI Vesta's UV lightcurve: hemispheric variation in brightness and spectral reversal SO ICARUS LA English DT Article DE asteroids, Vesta; ultraviolet observations; surfaces, asteroids ID SPACE-TELESCOPE IMAGES; ASTEROID 4-VESTA; 4 VESTA; SURFACE; LUNAR; SPECTROSCOPY; REFLECTIVITY; METEORITES; SIZE AB Spectra of asteroid 4 Vesta obtained in October 1990 with the International Ultraviolet Explorer are reanalyzed and reinterpreted. A large portion of the eastern hemisphere (based on the prime meridian definition of Thomas et al., 1997a) is darker at UV wavelengths than much of the western hemisphere. The UV lightcurve is in contrast with the visible lightcurve, which shows that the eastern hemisphere is brighter than the western. These IUE spectra of Vesta thus may be evidence for the "spectral reversal," first seen on the Moon by Apollo 17, where the visibly brighter lunar highlands are darker than the maria at far-UV wavelengths. This effect was linked to space weathering when it was noted (Wagner et al., 1987) that the spectral reversal appears in the laboratory spectra of lunar soils but not powdered lunar rocks. We investigate Vesta's UV lightcurve and spectral reversal, and its possible connection with space weathering. The addition to grain coatings of small amounts of submicroscopic iron (SMFe) through vapor deposition causes drastic spectral changes at UV-visible wavelengths (Hapke, 2001), while the longer wavelength spectrum remains largely unaffected. Other laboratory results (e.g., Hiroi and Pieters, 1998) indicate that the UV-visible wavelength range is affected by simulated weathering processes in a manner similar to what is seen on Vesta. It is likely that Vesta has experienced relatively minor amounts of space weathering, as indicated by the spectral reversal, along with the subtle visible-near infrared weathering effects (e.g., Binzel et al., 1997). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Observ Midi Pyrenees, F-31400 Toulouse, France. NASA, Lyndon B Johnson Space Ctr, SR, Houston, TX 77058 USA. RP Hendrix, AR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM hendrix@jpl.nasa.gov NR 31 TC 13 Z9 13 U1 0 U2 2 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD MAR PY 2003 VL 162 IS 1 BP 1 EP 9 DI 10.1016/S0019-1035(02)00070-2 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 658FG UT WOS:000181710500001 ER PT J AU French, RG McGhee, CA Dones, L Lissauer, JJ AF French, RG McGhee, CA Dones, L Lissauer, JJ TI Saturn's wayward shepherds: the peregrinations of Prometheus and Pandora SO ICARUS LA English DT Article DE satellites of Saturn; celestial mechanics; resonances; orbits ID RING PLANE CROSSINGS; F-RING; VOYAGER OBSERVATIONS; HST OBSERVATIONS; SMALL SATELLITES; SYSTEM; OCCULTATION; EVOLUTION; ORBITS; EPHEMERIDES AB Saturn's narrow F ring is flanked by two nearby small satellites, Prometheus and Pandora, discovered in Voyager images taken in 1980 and 1981 (Synnott et al., 1983, Icarus 53, 156-158). Observations with the Hubble Space Telescope (HST) during the ring plane crossings (RPX) of 1995 led to the unexpected finding that Prometheus was similar to19degrees behind its predicted orbital longitude, based on the Synnott et al. (1983) Voyager ephemeris (Bosh and Rivkin, 1996 Science 272, 518-521; Nicholson et al., 1996, Science 272, 509-515). Whereas Pandora was at its predicted location in August 1995, McGhee (2000, Ph.D. thesis, Cornell University) found from the May and November 1995 RPX data that Pandora also deviates from the Synnott et al. (1983) Voyager ephemeris. Using archival HST data from 1994, previously unexamined RPX images, and a large series of targeted WFPC2 observations between 1996 and 2002, we have determined highly accurate sky-plane positions for Prometheus, Pandora, and nine other satellites found in our images. We compare the Prometheus and Pandora measurements to the predictions of substantially revised and improved ephemerides for the two satellites based on an extensive analysis of a large set of Voyager images (Murray et al., 2000, Bull. Am. Astron. Soc. 32, 1090; Evans, 2001 Ph.D. thesis, Queen Mary College). From December 1994 to December 2000, Prometheus' orbital longitude lag was changing by -0.71degrees year(-1) relative to the new Voyager ephemeris. In contrast, Pandora is ahead of the revised Voyager prediction. From 1994 to 2000, its longitude offset changed by +0.44degrees year(-1), showing in addition an similar to585 day oscillatory component with amplitude Deltalambda(CR0) = 0.65 +/- 0.07degrees whose phase matches the expected perturbation due to the nearby 3:2 corotation resonance with Mimas, modulated by the 71-year libration in the longitude of Mimas due to its 4:2 resonance with Tethys. We determine orbital elements for freely precessing equatorial orbits from fits to the 1994-2000 HST observations, from which we conclude that Prometheus' semimajor axis was 0.31 km larger, and Pandora's was 0.20 km smaller, than during the Voyager epoch. Subsequent observations in 2001-2002 reveal a new twist in the meanderings of these satellites: Prometheus' mean motion changed suddenly by an additional -0.77degrees year(-1), equivalent to a further increase in semimajor axis of 0.33 km, at the same time that Pandora's mean motion changed by +0.92degrees year(-1), corresponding to a change of -0.42 km in its semimajor axis. There is an apparent anticorrelation of the motions of these two moons seen in the 2001-2002 observations, as well as over the 20-year interval since the Voyager epoch. This suggests a common origin for their wanderings, perhaps through direct exchange of energy between the satellites as the result of resonances, possibly involving the F ring. (C) 2003 Elsevier Science (USA). All rights reserved. C1 Wellesley Coll, Dept Astron, Wellesley, MA 02481 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. SW Res Inst, Boulder, CO 80302 USA. RP French, RG (reprint author), Wellesley Coll, Dept Astron, Wellesley, MA 02481 USA. EM rfrench@wellestey.edu NR 62 TC 36 Z9 37 U1 0 U2 1 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD MAR PY 2003 VL 162 IS 1 BP 143 EP 170 DI 10.1016/S0019-1035(02)00050-7 PG 28 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 658FG UT WOS:000181710500012 ER PT J AU Buratti, BJ Hillier, JK Heinze, A Hicks, MD Tryka, KA Mosher, JA Ward, J Garske, A Young, J Atienza-Rosel, J AF Buratti, BJ Hillier, JK Heinze, A Hicks, MD Tryka, KA Mosher, JA Ward, J Garske, A Young, J Atienza-Rosel, J TI Photometry of Pluto in the last decade and before: evidence for volatile transport? SO ICARUS LA English DT Article DE Pluto, surfaces, planets; photometry ID MUTUAL EVENT LIGHTCURVES; VOYAGER PHOTOMETRY; ATMOSPHERE; SURFACE; CHARON; METHANE; TRITON; ALBEDO; SATELLITES; SPECTROPHOTOMETRY AB Photometric observations of Pluto in the BVR filter system were obtained in 1999 and in 1990-1993, and observations in the 0.89-mum methane absorption band were obtained in 2000. Our 1999 observations yield lightcurve amplitudes of 0.30 +/- 0.01, 0.26 +/- 0.01, and 0.21 +/- 0.02 and geometric albedos of 0.44 +/- 0.04, 0.52 +/- 0.03, and 0.58 +/- 0.02 in the B, V, and R filters, respectively. The low-albedo hemisphere of Pluto is slightly redder than the higher albedo hemisphere. A comparison of our results and those from previous epochs shows that the lightcurve of Pluto changes substantially through time. We developed a model that fully accounts for changes in the lightcurve caused by changes in the viewing geometry between the Earth, Pluto, and the Sun. We find that the observed changes in the amplitude of Pluto's lightcurve can be explained by viewing geometry rather than by volatile transport. We also discovered a measurable decrease since 1992 of similar to0.03 magnitudes in the amplitude of Pluto's lightcurve, as the model predicts. Pluto's geometric albedo does not appear to be currently increasing, as our model predicts, although given the uncertainties in both the model and the measurements of geometric albedo, this result is not firm evidence for volatile transport. The maximum of methane-absorption lightcurve occurs near the minimum of the BVR lightcurves. This result suggests that methane is more abundant in the brightest regions of Pluto. Pluto's phase coefficient exhibits a color dependence, ranging from 0.037 +/- 0.01 in the B filter to 0.032 +/- 0.01 in the R filter. Pluto's phase curve is most like those of the bright, recently resurfaced satellites Triton and Europa. Although Pluto shows no strong evidence for volatile transport now (unlike Triton), it is important to continue to observe Pluto as it moves away from perihelion. (C) 2003 Elsevier Science (USA). All rights reserved. C1 CALTECH, Jet Prop Lab, Palomar Observ, Pasadena, CA 91109 USA. Calif State Univ Los Angeles, Dept Phys & Astron, Los Angeles, CA 90032 USA. RP Buratti, BJ (reprint author), CALTECH, Jet Prop Lab, Palomar Observ, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM bonnie.buratti@jpl.nasa.gov OI Tryka, Kimberly/0000-0002-5399-4235 NR 60 TC 20 Z9 20 U1 0 U2 2 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD MAR PY 2003 VL 162 IS 1 BP 171 EP 182 DI 10.1016/S0019-1035(02)00068-4 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 658FG UT WOS:000181710500013 ER PT J AU Spooner, DP Jarvis, SA Cao, J Saini, S Nudd, GR AF Spooner, DP Jarvis, SA Cao, J Saini, S Nudd, GR TI Local grid scheduling techniques using performance prediction SO IEE PROCEEDINGS-COMPUTERS AND DIGITAL TECHNIQUES LA English DT Article; Proceedings Paper CT 18th United Kingdom Performance Engineering Workshop (UKPEW) CY JUL 10-11, 2002 CL GLASGOW UNIV, GLASGOW, SCOTLAND HO GLASGOW UNIV ID SYSTEMS; PARALLEL; SERVICE AB The use of computational grids to provide an integrated computer platform, composed of differentiated and distributed systems, presents fundamental resource and workload management questions. Key services such as resource discovery, monitoring and scheduling are inherently more complicated in a grid environment Where the resource pool is large, dynamic and architecturally diverse. The authors approach the problem of grid workload management through the development of a multi-tiered scheduling architecture (TITAN) that employs a performance prediction system (PACE) and task distribution brokers to meet user-defined deadlines and improve resource usage efficiency. Attention is focused on the lowest tier which is responsible for local scheduling. By coupling application performance data with scheduling heuristics, the architecture is able to balance the processes of minimising run-to-completion time and processor idle time, whilst adhering to service deadlines on a per-task basis. C1 Univ Warwick, Dept Comp Sci, High Performance Syst Grp, Coventry CV4 7AL, W Midlands, England. NEC Europe Ltd, C&C Res Labs, St Augustin, Germany. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Spooner, DP (reprint author), Univ Warwick, Dept Comp Sci, High Performance Syst Grp, Coventry CV4 7AL, W Midlands, England. NR 34 TC 65 Z9 71 U1 0 U2 1 PU INST ENGINEERING TECHNOLOGY-IET PI HERTFORD PA MICHAEL FARADAY HOUSE SIX HILLS WAY STEVENAGE, HERTFORD SG1 2AY, ENGLAND SN 1350-2387 J9 IEE P-COMPUT DIG T JI IEE Proc.-Comp. Digit. Tech. PD MAR PY 2003 VL 150 IS 2 BP 87 EP 96 DI 10.1049/ip-cdt:20030280 PG 10 WC Computer Science, Hardware & Architecture; Computer Science, Theory & Methods SC Computer Science GA 674VA UT WOS:000182656500004 ER PT J AU Bloomberg, JJ Mulavara, AP AF Bloomberg, JJ Mulavara, AP TI Changes in walking strategies after spaceflight SO IEEE ENGINEERING IN MEDICINE AND BIOLOGY MAGAZINE LA English DT Article ID NEUROMUSCULAR ACTIVATION PATTERNS; SPACE-FLIGHT; HEAD STABILIZATION; TREADMILL WALKING; SPATIAL ORIENTATION; LOWER-LIMB; LOCOMOTION; COORDINATION; KINEMATICS; MOVEMENTS C1 NASA, Lyndon B Johnson Space Ctr, Neurosci Lab, Houston, TX 77058 USA. RP Bloomberg, JJ (reprint author), NASA, Lyndon B Johnson Space Ctr, Neurosci Lab, Mail Code SK3, Houston, TX 77058 USA. NR 21 TC 32 Z9 33 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0739-5175 J9 IEEE ENG MED BIOL JI IEEE Eng. Med. Biol. Mag. PD MAR-APR PY 2003 VL 22 IS 2 BP 58 EP 62 DI 10.1109/MEMB.2003.1195697 PG 5 WC Engineering, Biomedical; Medical Informatics SC Engineering; Medical Informatics GA 671YX UT WOS:000182494200013 PM 12733460 ER PT J AU Kortenkamp, D AF Kortenkamp, D TI A day in an astronaut's life: Reflections on advanced planning and scheduling technology SO IEEE INTELLIGENT SYSTEMS LA English DT Editorial Material C1 NASA, Johnson Space Ctr, Metrica Inc, Houston, TX 77058 USA. RP Kortenkamp, D (reprint author), NASA, Johnson Space Ctr, Metrica Inc, Houston, TX 77058 USA. NR 12 TC 4 Z9 4 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 1094-7167 J9 IEEE INTELL SYST JI IEEE Intell. Syst. PD MAR-APR PY 2003 VL 18 IS 2 BP 8 EP 11 DI 10.1109/MIS.2003.1193650 PG 4 WC Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Computer Science; Engineering GA 661BA UT WOS:000181870300004 ER PT J AU Hoorfar, A Jamnejad, V AF Hoorfar, A Jamnejad, V TI Electromagnetic modeling and analysis of wireless communication antennas SO IEEE MICROWAVE MAGAZINE LA English DT Article ID ABSORBING BOUNDARY-CONDITIONS; FINITE-ELEMENT METHOD; POTENTIAL INTEGRAL-EQUATION; PERFECTLY MATCHED LAYER; SCATTERING PROBLEMS; MICROSTRIP STRUCTURES; MAXWELLS EQUATIONS; NUMERICAL-SOLUTION; GREENS-FUNCTION; WAVE-EQUATION C1 Villanova Univ, Dept Elect & Comp Engn, Villanova, PA 19085 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hoorfar, A (reprint author), Villanova Univ, Dept Elect & Comp Engn, Villanova, PA 19085 USA. NR 58 TC 6 Z9 6 U1 1 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1527-3342 J9 IEEE MICROW MAG JI IEEE Microw. Mag. PD MAR PY 2003 VL 4 IS 1 BP 51 EP 67 DI 10.1109/MMW.2003.1188236 PG 17 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA 741ZP UT WOS:000186490500007 ER PT J AU Rabinovich, WS Mahon, R Goetz, PG Waluschka, E Katzer, DS Binari, SC Gilbreath, GC AF Rabinovich, WS Mahon, R Goetz, PG Waluschka, E Katzer, DS Binari, SC Gilbreath, GC TI A cat's eye multiple quantum-well modulating retro-reflector SO IEEE PHOTONICS TECHNOLOGY LETTERS LA English DT Article DE optical communication; optical modulation; quantum-well devices AB A new kind of modulating retro-reflector using cat's eye optics and a multiple quantum-well electro-absorption modulator array is described. The device exhibits retro-reflection over a 30degrees field of view and can support data rates of up to 50 Mb/s using 1-mm pixels. The use of the device in free-space optical communication is discussed. C1 USN, Res Lab, Code 5650, Washington, DC 20375 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20768 USA. RP Rabinovich, WS (reprint author), USN, Res Lab, Code 5650, Washington, DC 20375 USA. RI Katzer, D. Scott/N-7841-2013 NR 7 TC 45 Z9 48 U1 2 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 1041-1135 J9 IEEE PHOTONIC TECH L JI IEEE Photonics Technol. Lett. PD MAR PY 2003 VL 15 IS 3 BP 461 EP 463 DI 10.1109/LPT.2002.807904 PG 3 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 650MG UT WOS:000181267500035 ER PT J AU Kulkarni, NV KrishnaKumar, K AF Kulkarni, NV KrishnaKumar, K TI Intelligent engine control using an adaptive critic SO IEEE TRANSACTIONS ON CONTROL SYSTEMS TECHNOLOGY LA English DT Article DE adaptive control; adaptive critic; intelligent control; jet engines; neural networks (NNs); optimization methods AB Neural networks (NNs) have been successfully used for implementing control architectures for different applications. In this paper, we examine NN augmented intelligent control of a turbo-fan engine toward the goal of minimizing a performance measure on-line. This architecture utilizes an adaptive critic to estimate the engine performance, which is then used to train an NN demand generator for minimizing the performance measure. The present architecture is implemented on a nonlinear model that was provided by General Electric. The model simulates a changed engine by changing the flow and efficiency scalars of the various components of the engine. Results, of using the adaptive critic-based performance seeking control architecture show excellent improvement in performance over time. C1 Princeton Univ, Princeton, NJ 08540 USA. NASA, Ames Res Ctr, Neuroengn Lab, Moffett Field, CA 94035 USA. RP Kulkarni, NV (reprint author), Princeton Univ, Princeton, NJ 08540 USA. EM nkulkarn@princeton.edu; kkumar@mail.arc.nasa.gov NR 18 TC 15 Z9 16 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1063-6536 J9 IEEE T CONTR SYST T JI IEEE Trans. Control Syst. Technol. PD MAR PY 2003 VL 11 IS 2 BP 164 EP 173 DI 10.1109/TCST.2003.809254 PG 10 WC Automation & Control Systems; Engineering, Electrical & Electronic SC Automation & Control Systems; Engineering GA 656UG UT WOS:000181626700001 ER PT J AU Li, RR Kaufman, YJ Gao, BC Davis, CO AF Li, RR Kaufman, YJ Gao, BC Davis, CO TI Remote sensing of suspended sediments and shallow coastal waters SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE aerosol; remote sensing; ocean ID ZONE COLOR SCANNER; MODIS; AEROSOL; SYSTEM AB Ocean color sensors were designed mainly for remote sensing of chlorophyll concentrations over the clear open oceanic areas (Case 1 water) using channels between 0.4-0.86 mum. The Moderate Resolution Imaging Spectroradiometer (MODIS) launched on the National Aeronautics and Space Administration Terra and Aqua spacecrafts is equipped with narrow channels located within a wider wavelength range between 0.4-2.5 mum for a variety of remote sensing applications. The wide spectral range can provide improved capabilities for remote sensing of the more complex and turbid coastal waters (Case 2 water) and for improved atmospheric corrections for ocean scenes. In this paper, we describe an empirical algorithm that uses this wide spectral range to identify areas with suspended sediments in turbid waters and shallow waters with bottom reflections. The algorithm takes advantage of the strong water absorption at wavelengths longer than 1 mum that does not allow illumination of sediments in the water or a shallow ocean floor. MODIS data acquired over the east coast of China, west coast of Africa, Arabian Sea, Mississippi Delta, and west coast of Florida are used in this study. C1 NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, Greenbelt, MD 20771 USA. USN, Res Lab, Remote Sensing Div, Washington, DC 20375 USA. RP Li, RR (reprint author), NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, Greenbelt, MD 20771 USA. NR 15 TC 79 Z9 87 U1 3 U2 25 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD MAR PY 2003 VL 41 IS 3 BP 559 EP 566 DI 10.1109/TGRS.2003.810227 PG 8 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 678MQ UT WOS:000182871300006 ER PT J AU Spencer, MW Tsai, WY Long, DG AF Spencer, MW Tsai, WY Long, DG TI High-resolution measurements with a spaceborne pencil-beam scatterometer using combined range/doppler discrimination techniques SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE ocean winds; radar; backscatter ID SEA-ICE; NSCAT WINDS; VEGETATION; SEAWINDS; IMPACT; OCEAN AB Conically scanning pencil-beam scatterometer systems, such as the recently launched SeaWinds radar, constitute an important class of instruments for spaceborne climate observation. In addition to ocean winds, scatterometer data are being applied to a wide range of land and cryospheric applications. A key issue for future scatterometer missions is improved spatial resolution. Pencil-beam scatterometers to date have been real-aperture systems where only range discrimination is used, resulting in a relatively coarse resolution of approximately 25 km. In this paper, the addition of Doppler discrimination techniques is proposed to meet the need for higher resolution. Here, the unique issues associated with the simultaneous application of range and Doppler processing to a conically scanning radar are addressed, and expressions for the theoretical measurement performance of such a system are derived. Important differences with side-looking imaging radars, which also may employ Doppler techniques, are highlighted. Conceptual design examples based on scatterometer missions of current interest are provided to illustrate this new high-resolution scatterometer approach. It is shown that spatial resolution of pencil-beam scatterometer systems can be improved by an order of magnitude by utilizing combined range/Doppler discrimination techniques, while maintaining the wide-swath and constant incidence angle neaaaaeded for many geophysical measurements. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Brigham Young Univ, Dept Elect & Comp Engn, Microwave Earth Remote Sensing Lab, Provo, UT 84602 USA. RP Spencer, MW (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Long, David/K-4908-2015 OI Long, David/0000-0002-1852-3972 NR 37 TC 21 Z9 23 U1 1 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD MAR PY 2003 VL 41 IS 3 BP 567 EP 581 DI 10.1109/TGRS.2003.809938 PG 15 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 678MQ UT WOS:000182871300007 ER PT J AU Wang, JR Manning, W AF Wang, JR Manning, W TI Retrievals of low integrated water vapor using MIR and SSM/T-2 measurements SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE millimeter-wave; radiometry; remote sensing; precipitable water ID TOTAL PRECIPITABLE WATER; WAVE IMAGING RADIOMETER; 183 GHZ; MICROWAVE RADIOMETRY; SNOW; SPECTROMETER; EMISSIVITY; PROFILES; CLOUD; MODEL AB Satellite radiometric measurements at 150, 183.3 +/- 3, and 183.3 +/- 7 GHz have previously been used to retrieve integrated water vapor < 1 g/cm over Antarctica. The effects of the frequency dependence of surface emissivity and the variation of surface temperature on the retrieval, which have not been closely examined in the studies, are analyzed. Using four days of near-concurrent airborne and satellite radiometric measurements, it is shown that the previously derived, retrieval algorithm could overestimate or underestimate integrated water vapor by up to 0.1 g/cm(2), a depending on whether the surface emissivity increases or decreases, with frequency. The Average of the absolute value of the bias for each flight case studied is < 0.04 g/cm(2). Additionally, surface skin temperature is shown to vary substantially over A range from 240-270 K during these four days of measurements; the corresponding effect on the retrieval of integrated water vapor is comparable to that due to frequency dependence on surface emissivity. The quantitative correction needed for this effect is dependent upon the magnitude,of integrated water vapor. At high values of integrated water vapor of 0.6-0.8 g/cm(2) the corrections are as large as 0.1 g/cm(2) for changes of surface temperature of +/- 10 K. A simple procedure is implemented to correct for this error, which, significantly improves the retrieval. Correction for the frequency dependence of surface emissivity is nontrivial when using currently available, satellite measurements; in order to properly correct this effect, an additional channel of measurements, e.g., at 220 GHz, is required. C1 NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21250 USA. RP Wang, JR (reprint author), NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. NR 26 TC 7 Z9 7 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD MAR PY 2003 VL 41 IS 3 BP 630 EP 639 DI 10.1109/TGRS.2003.809933 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 678MQ UT WOS:000182871300013 ER PT J AU Elbuluk, ME Hammoud, A Gerber, S Patterson, R Overton, E AF Elbuluk, ME Hammoud, A Gerber, S Patterson, R Overton, E TI Performance of high-speed PWM control chips at cryogenic temperatures SO IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS LA English DT Article; Proceedings Paper CT Annual Meeting of the Industry-Applications-Society CY SEP 30-OCT 05, 2001 CL CHICAGO, ILLINOIS SP Ind Applicat Soc DE cryogenic electronics; current-mode pulsewidth modulation (PWM) control; dc/dc converters; deep space power; pulsewidth modulation (PWM) ICs; voltage-mode pulsewidth modulation (PWM) control AB Planetary exploration missions and deep space probes require electronics capable of low-temperature operation. Such electronics will not only improve circuit performance and reliability, but also increase system efficiency, and reduce development and launch costs. DC/DC converters are an essential part of most aerospace power management distribution systems. Therefore, dc/dc converters that can operate at cryogenic temperatures are crucial for space missions where low temperatures are encountered. An important component of a dc/dc converter is the pulse width modulation (PWM) chip that provides the control to the converter main switches. In the process of designing low-temperature dc/dc converters, experimental investigations were carried out to evaluate the performance of a number of high-speed PWM chips as a function of temperature in the range of 25 degreesC to -190 degreesC. These IC chips ranged in their electrical characteristics, modes of control, packaging options, and applications. This paper presents and discusses the experimental procedures along with the experimental data obtained on the investigated chips. C1 Univ Akron, Akron, OH 44325 USA. NASA, Glenn Res Ctr, QSS Grp Inc, Cleveland, OH 44135 USA. ZIN Technol, Brookpark, OH 44142 USA. NASA, Glenn Res Ctr, Power & Board Propuls Technol, Cleveland, OH 44135 USA. RP Elbuluk, ME (reprint author), Univ Akron, Akron, OH 44325 USA. EM melbuluk@uakron.edu; ahmad.hammoud@grc.nasa.gov; scott.s.gerber@grc.nasa.gov; Richard.l.patterson@grc.nasa.gov; Eric.overton@grc.nasa.gov NR 15 TC 5 Z9 5 U1 0 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0093-9994 J9 IEEE T IND APPL JI IEEE Trans. Ind. Appl. PD MAR-APR PY 2003 VL 39 IS 2 BP 443 EP 450 DI 10.1109/TIA.2003.808974 PG 8 WC Engineering, Multidisciplinary; Engineering, Electrical & Electronic SC Engineering GA 659BQ UT WOS:000181757500019 ER PT J AU Mojarradi, M Binkley, D Blalock, B Andersen, R Ulshoefer, N Johnson, T Del Castillo, L AF Mojarradi, M Binkley, D Blalock, B Andersen, R Ulshoefer, N Johnson, T Del Castillo, L TI A miniaturized neuroprosthesis suitable for implantation into the brain SO IEEE TRANSACTIONS ON NEURAL SYSTEMS AND REHABILITATION ENGINEERING LA English DT Article DE bio-MEMS; brain; complementary metal-oxide-semiconductor; (CMOS) micropower; computer interface; cortical signals; heterogeneous integration; integrated-circuit electronics; low-noise preamplifiers; microelectromechanical system (MEMS); packaging; microelectromechanical system (MEMS) probe; neuroprosthesis; neuroprosthetic devices AB This paper presents current research on a miniaturized neuroprosthesis suitable for implantation into the brain. The prosthesis is a heterogeneous integration of a 100-element micro-electromechanical system (MEMS) electrode array, front-end complementary metal-oxide-semiconductor (CMOS) integrated circuit for neural signal preamplification, filtering, multiplexing and analog-to-digital conversion, and a second CMOS integrated circuit for wireless transmission of neural data and conditioning of wireless power. The prosthesis is intended for applications where neural signals are processed and decoded to permit the control of artificial or paralyzed limbs. This research, if successful, will allow implantation of the electronics into the brain, or subcutaneously on the skull, and eliminate all external signal and power wiring. The neuroprosthetic system design has strict size and power constraints with each of the front-end preamplifier channels fitting within the 400 x 400-mum pitch of the 100-element MEMS electrode array and power dissipation resulting in less than a 1degreesC temperature rise for the surrounding brain tissue. We describe the measured performance of initial micropower low-noise CMOS preamplifiers for the neuroprosthetic. C1 NASA, Jet Prop Lab, Pasadena, CA 91109 USA. Univ N Carolina, Dept Elect & Comp Engn, Charlotte, NC 28223 USA. CALTECH, Dept Biol, Pasadena, CA 91125 USA. RP Mojarradi, M (reprint author), NASA, Jet Prop Lab, Pasadena, CA 91109 USA. NR 7 TC 53 Z9 54 U1 1 U2 14 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 1534-4320 J9 IEEE T NEUR SYS REH JI IEEE Trans. Neural Syst. Rehabil. Eng. PD MAR PY 2003 VL 11 IS 1 BP 38 EP 42 DI 10.1109/TNSRE.2003.810431 PG 5 WC Engineering, Biomedical; Rehabilitation SC Engineering; Rehabilitation GA 682FZ UT WOS:000183082200006 PM 12797724 ER PT J AU Bell, AM Sethares, WA Bucklew, JA AF Bell, AM Sethares, WA Bucklew, JA TI Coordination failure as a source of congestion in information networks SO IEEE TRANSACTIONS ON SIGNAL PROCESSING LA English DT Article DE adaptation; decentralized networks; El Farol; habit formation; learning; minority game; weak convergence ID ALGORITHMS AB Coordination failure, or agents' uncertainty about the action of other agents, may be an important source of congestion in large decentralized systems. The El Farol problem provides a simple paradigm for congestion and coordination problems that may arise with over utilization of the Internet. This paper reviews the El Farol problem and surveys previous approaches, which typically involve complex deterministic learning algorithms that exhibit chaotic-like trajectories. This paper recasts the problem in a stochastic framework and derives a simple adaptive strategy that has intriguing optimization properties; a large collection of decentralized decision makers, each acting in their own best interests and with limited knowledge, converge to a solution that (optimally) solves a complex congestion and social coordination problem. A variation in which agents are allowed access to full information is not nearly as successful. The algorithm, which can be viewed as a kind of habit formation, is analyzed using a weak convergence approach, and simulations illustrate the major results. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Wisconsin, Dept Elect & Comp Engn, Madison, WI 53706 USA. RP Bell, AM (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 24 TC 6 Z9 7 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 1053-587X J9 IEEE T SIGNAL PROCES JI IEEE Trans. Signal Process. PD MAR PY 2003 VL 51 IS 3 BP 875 EP 885 DI 10.1109/TSP.2002.808139 PG 11 WC Engineering, Electrical & Electronic SC Engineering GA 647NH UT WOS:000181099200026 ER PT J AU Xu, GW Ikegami, M Honma, S Ikeda, K Ma, XX Nagaishi, H Dietrich, DL Struk, PM AF Xu, GW Ikegami, M Honma, S Ikeda, K Ma, XX Nagaishi, H Dietrich, DL Struk, PM TI Inverse influence of initial diameter on droplet burning rate in cold and hot ambiences: a thermal action of flame in balance with heat loss SO INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER LA English DT Article DE microgravity combustion; droplet combustion; flame radiation; soot; initial diameter influence ID COMBUSTION; MICROGRAVITY; RADIATION; HEPTANE; MIXTURES AB Isolated droplet burning were conducted in microgravity ambiences of different temperatures to test the initial diameter influence on droplet burning rate that shows a flame scale effect and represents an overall thermal action of flame in balance with heat loss. The coldest ambience examined was room air, which utilized a heater wire to ignite the droplet. All other ambiences hotter than 633 K were acquired through an electrically heated air chamber in a stainless steel can. An inverse influence of initial droplet diameter on burning rate was demonstrated for the cold and hot ambiences. That is, the burning rate respectively decreased and increased in the former and latter cases with raising the initial droplet diameter. The reversion between the two influences appeared gradual. In the hot ambiences the burning rate increase with increasing the initial droplet diameter was larger at higher temperatures. A "net heat" of flame that denotes the difference between "heat gain" by the droplet and "heat loss" to the flame surrounding was suggested responsible for the results. In low-temperature ambiences there is a negative net heat, and it turns gradually positive as the ambience temperature gets higher and the heat loss becomes less. Relating to luminous flame sizes and soot generation of differently sized droplets clarified that the flame radiation, both non-luminous and luminous, is determinative to the net heat in microgravity conditions. In addition, the work identified two peak values of soot generation during burning, which appeared respectively at the room temperature and at about 1000 K. The increase in ambience temperature made also bigger soot shells. The heat contribution of flame by both radiation and conduction was demonstrated hardly over 40% in the total heat required for droplet vaporization during burning in a hot ambience of 773 K. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 Natl Inst Adv Ind Sci & Technol, AIST, Sapporo, Hokkaido 0628517, Japan. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Natl Ctr Micrograv Res, Cleveland, OH 44135 USA. RP Ikegami, M (reprint author), Natl Inst Adv Ind Sci & Technol, AIST, Sapporo, Hokkaido 0628517, Japan. NR 40 TC 28 Z9 31 U1 0 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0017-9310 J9 INT J HEAT MASS TRAN JI Int. J. Heat Mass Transf. PD MAR PY 2003 VL 46 IS 7 BP 1155 EP 1169 AR PII S0017-9310(02)00397-6 DI 10.1016/S0017-9310(02)00397-6 PG 15 WC Thermodynamics; Engineering, Mechanical; Mechanics SC Thermodynamics; Engineering; Mechanics GA 651CA UT WOS:000181301700003 ER PT J AU Cockell, CS Lim, DSS Braham, S Lee, P Clancey, B AF Cockell, CS Lim, DSS Braham, S Lee, P Clancey, B TI Exobiological protocol and laboratory for the human exploration of Mars - Lessons from a polar impact crater SO JBIS-JOURNAL OF THE BRITISH INTERPLANETARY SOCIETY LA English DT Article DE exobiology; Mars; human missions; lander; EVA; communication; paleolake; impact crater; Haughton ID ANTARCTICA; ECOLOGY; ALGAE AB The search for life (or the examination of the reasons for its absence) is one of the most compelling scientific activities on Mars. We describe the study of the microbiology of the Haughton impact crater in the Canadian Arctic, from a simulated Mars lander (the FMARS). Impact events have had a profound influence on Mars, and thus on any putative microbial habitats that future explorers might seek. The study of microbial habitats was accomplished under simulated EVA time constraints and with simulated Mars communications. The work was catalogued to develop a computer model for Mars mission planning - 'Brahms'. We implemented a program of cosmic ray dosimeter deployment and we describe how sampling of paleolake deposits might be accomplished from a lander. We domonstrate that science on the surface of Mars can be accomplished from the testing of hypotheses through to the preparation of peer-reviewed manuscripts during a long-duration stay, a significant difference to merely sampling as on the Apollo expeditions. The design of a Martian surface exobiology laboratory is described. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Toronto, Dept Geol, Paleoenvironm Assessment Lab, Toronto, ON M5S 3B1, Canada. Simon Fraser Univ, PolyLAB, Adv Collaborat Networking Lab, Vancouver, BC, Canada. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Cockell, CS (reprint author), NASA, Ames Res Ctr, MS 245-3, Moffett Field, CA 94035 USA. EM csco@bas.ac.uk NR 13 TC 2 Z9 2 U1 1 U2 3 PU BRITISH INTERPLANETARY SOC PI LONDON PA 27-29 S LAMBETH RD, LONDON SW8 1SZ, ENGLAND SN 0007-084X J9 JBIS-J BRIT INTERPLA JI JBIS-J. Br. Interplanet. Soc. PD MAR-APR PY 2003 VL 56 IS 3-4 BP 74 EP 86 PG 13 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Engineering; Astronomy & Astrophysics; Geology GA 656EB UT WOS:000181594900001 ER PT J AU Bolonkin, A AF Bolonkin, A TI Optimal inflatable space towers with 3-100 km height SO JBIS-JOURNAL OF THE BRITISH INTERPLANETARY SOCIETY LA English DT Article DE space tower; inflatable; high height; optimal AB Theory and computations are provided for building inflatable space towers up to one hundred kilometres in height. These towers can be used for tourism, scientific observation of space, observation of the Earth's surface, weather and upper atmosphere, and for radio, television, and communication transmissions. These towers can also be used to launch space ships and Earth satellites. These projects are not expensive and do not require rockets. They require thin strong films composed from artificial fibers and fabricated by current industry. The towers can be built using present technology. The towers can be used (for tourism, communication, etc.) during the construction process and provide self-financing for further construction. The tower design does not require work at high altitudes; all construction can be done at the Earth's surface. The transport system for a tower consists of a small engine (used only for friction compensation) located at the Earth's surface. The tower is separated into sections and has special protection mechanisms in case of damage. Problems involving security, control, repair, and stability of the proposed towers are addressed in other publications. The author is prepared to discuss these and other problems with serious organizations desiring to research and develop these projects. C1 NRC, Eglin AFB, FL 32542 USA. NASA, Washington, DC 20546 USA. RP Bolonkin, A (reprint author), NRC, Eglin AFB, FL 32542 USA. NR 10 TC 10 Z9 10 U1 0 U2 1 PU BRITISH INTERPLANETARY SOC PI LONDON PA 27-29 S LAMBETH RD, LONDON SW8 1SZ, ENGLAND SN 0007-084X J9 JBIS-J BRIT INTERPLA JI JBIS-J. Br. Interplanet. Soc. PD MAR-APR PY 2003 VL 56 IS 3-4 BP 87 EP 97 PG 11 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Engineering; Astronomy & Astrophysics; Geology GA 656EB UT WOS:000181594900002 ER PT J AU Bolonkin, A AF Bolonkin, A TI Asteroids as propulsion systems of space ships SO JBIS-JOURNAL OF THE BRITISH INTERPLANETARY SOCIETY LA English DT Article DE propulsion system; asteroids; comets; trajectory change ID EARTH-CROSSING ASTEROIDS; COMET SHOEMAKER-LEVY-9; RADAR IMAGES; RUBBLE PILES; NUCLEI AB Currently, rockets are used to change the trajectory of space ships and probes. This method is very expensive and requires a lot of fuel, which limits the feasibility of space stations, interplanetary space ships, and probes. Sometimes space probes use the gravity field of a planet. However, there are only nine planets in the Solar System, all separated by great distances. There are tens of millions of asteroids in outer space. This paper offers a revolutionary method for changing the trajectory of space probes. The method uses the kinetic or rotary energy of asteroids, comet nuclei, meteorites or other space bodies (small planets, natural planetary satellites, space debris, etc.) to increase (to decrease) ship (probe) speed up to 1000 m/sec (or more) and to achieve any new direction in outer space. The flight possibilities of space ships and probes are increased by a factor of millions. C1 NRC, Eglin AFB, FL 32542 USA. NASA, Washington, DC 20546 USA. RP Bolonkin, A (reprint author), NRC, Eglin AFB, FL 32542 USA. NR 25 TC 5 Z9 5 U1 0 U2 2 PU BRITISH INTERPLANETARY SOC PI LONDON PA 27-29 S LAMBETH RD, LONDON SW8 1SZ, ENGLAND SN 0007-084X J9 JBIS-J BRIT INTERPLA JI JBIS-J. Br. Interplanet. Soc. PD MAR-APR PY 2003 VL 56 IS 3-4 BP 98 EP 107 PG 10 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Engineering; Astronomy & Astrophysics; Geology GA 656EB UT WOS:000181594900003 ER PT J AU Flynn, GJ Keller, LP Wirick, S Jacobsen, C Sutton, SR AF Flynn, GJ Keller, LP Wirick, S Jacobsen, C Sutton, SR TI Analysis of interplanetary dust particles by soft and hard X-ray microscopy SO JOURNAL DE PHYSIQUE IV LA English DT Article; Proceedings Paper CT 7th International Conference on X-Ray Microscopy CY JUL 28-AUG 02, 2002 CL GRENOBLE, FRANCE AB Interplanetary dust particles (IDPs), fragments from asteroids and comets, contain important clues to the conditions in the solar nebula when dust was forming, provide evidence of the chemical and physical properties of their parent bodies, and may have been an important source of pre-biotic organic matter on the early Earth. We mapped the spatial distributions in IDPs of C, 0, K, and Ca using a scanning transmission x-ray microscope and of Fe, Ni, Zn, Sr and Br using fluorescence microtomography. In addition, we obtained carbon and oxygen x-ray absorption near-edge structure (XANES) spectra of the C-rich regions, identifying the C-ring and C=O functional groups, and Fourier Transform InfraRed (FTIR) spectra, identifying the aliphatic C-H-2 and C-H-3 functional groups. The C-mapping indicates that IDPs contain anywhere from a few wt-% up to 90 wt-% carbon, much more carbon than is found in the most carbon-rich meteorites, and G and O-XANES demonstrate that a significant fraction of this carbon is organic. The Ca, K, Fe, Ni, Zn, Sr, and Br maps allow inference of the host phases of these elements and place constraints on surface contamination. C1 SUNY Coll Plattsburgh, Dept Phys, Plattsburgh, NY 12901 USA. NASA, Johnson Space Ctr, Houston, TX 77051 USA. SUNY Stony Brook, Dept Phys, Stony Brook, NY 11794 USA. Univ Chicago, Dept Geophys Sci & CARS, Chicago, IL 60637 USA. RP Flynn, GJ (reprint author), SUNY Coll Plattsburgh, Dept Phys, Plattsburgh, NY 12901 USA. RI Jacobsen, Chris/E-2827-2015 OI Jacobsen, Chris/0000-0001-8562-0353 NR 10 TC 7 Z9 7 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 1155-4339 J9 J PHYS IV JI J. Phys. IV PD MAR PY 2003 VL 104 BP 367 EP 372 DI 10.1051/jp4:20030101 PG 6 WC Physics, Multidisciplinary SC Physics GA 685QC UT WOS:000183273900088 ER PT J AU Rossow, VJ AF Rossow, VJ TI Use of individual flight corridors to avoid vortex wakes SO JOURNAL OF AIRCRAFT LA English DT Article AB Vortex wakes of aircraft pose a hazard to following aircraft until the energetic parts of their flowfields have decayed to a harmless level. It is suggested here that in-trail spacings between aircraft can be significantly and safely reduced by designing an individual, vortex-free flight corridor for each aircraft. Because each aircraft will then have its own flight corridor, which is free of vortex wakes while in use by the assigned aircraft, the time intervals between aircraft operations can be safely reduced to the order of seconds. The productivity of airports can then, be substantially increased. How large the offset distances between operational corridors need to be to have them vortex free, and how airports need to be changed to accommodate an individual flight-corridor process for landing and takeoff operations, are explored. Estimates are then made of the productivity of an individual flight-corridor system as a function of the in-trail time interval between operations for various values of wake decay time, runway width, and the velocity of a sidewind. The results confirm the need for short time intervals between aircraft operations if smaller offset distances and increased productivity are to be achieved. C1 NASA, Ames Res Ctr, Aerosp Operat Modeling Off, Moffett Field, CA 94035 USA. RP Rossow, VJ (reprint author), NASA, Ames Res Ctr, Aerosp Operat Modeling Off, Mail Stop N210-10, Moffett Field, CA 94035 USA. NR 24 TC 5 Z9 5 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAR-APR PY 2003 VL 40 IS 2 BP 225 EP 231 DI 10.2514/2.3091 PG 7 WC Engineering, Aerospace SC Engineering GA 664KM UT WOS:000182060300001 ER PT J AU Green, BE Whitesides, JL AF Green, BE Whitesides, JL TI Method for designing leading-edge fillets to eliminate flow separation SO JOURNAL OF AIRCRAFT LA English DT Article AB A design method is presented whereby the flow separation in the wing-fuselage juncture of aircraft is eliminated by the use of a leading-edge fillet. The design method uses a design rule that relates a change in skin friction to a change in surface slope. After determining the current skin-friction distribution on the plate ahead of the leading edge of the wing, a target skin-friction distribution that will eliminate flow separation is calculated. By the use of the design rule, the current skin-friction distribution is moved toward the target distribution by extending the leading edge of the wing to form a leading-edge fillet. The new leading-edge fillet is then analyzed by the flow solver and the process is iterated until convergence is achieved. C1 George Washington Univ, NASA, Langley Res Ctr, Dept Mech & Aerosp Engn, Hampton, VA 23681 USA. George Washington Univ, NASA, Langley Res Ctr, Joint Inst Advancement Flight Sci, Hampton, VA 23681 USA. RP Green, BE (reprint author), USN, Air Syst Command, Bldg 2187,Unit 5,Suite 1320-B,48110 Shaw Rd, Patuxent River, MD 20670 USA. NR 12 TC 5 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 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAR-APR PY 2003 VL 40 IS 2 BP 282 EP 289 DI 10.2514/2.3121 PG 8 WC Engineering, Aerospace SC Engineering GA 664KM UT WOS:000182060300009 ER PT J AU Prigent, C Aires, F Rossow, WB AF Prigent, C Aires, F Rossow, WB TI Retrieval of surface and atmospheric geophysical variables over snow-covered land from combined microwave and infrared satellite observations SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID LIQUID WATER PATH; SUB-ARCTIC SNOW; BRIGHTNESS TEMPERATURE; REMOTE; EMISSIVITIES; VAPOR; ISCCP; INFORMATION; WAVELENGTHS; VEGETATION AB Surface temperature and emissivities, as well as atmospheric water vapor and cloud liquid water, have been calculated from Special Sensor Microwave Imager observations for snow-covered land areas using a neural network inversion scheme that includes first-guess information. A learning database to train the neural network is derived from a global collection of coincident surface and atmospheric parameters, extracted from the National Centers for Environmental Prediction reanalysis, from the International Satellite Cloud Climatology Project data, and from microwave emissivity atlases previously calculated. Despite the large space and time variability of the snow microwave response, the surface and atmospheric parameters are retrieved. Water vapor is estimated with a theoretical rms error of approximately 30%, verified against radiosonde measurements, that is almost the same as over snow-free land. The theoretical rms error of the surface skin temperature retrieval is 1.5 and 1.9 K, respectively, for clear and cloudy scenes. The surface skin temperatures are compared with the surface air temperatures measured at meteorological stations to verify that the expected differences are found. The space and time variations of the retrieved surface emissivities are evaluated by comparison with surface parameter variations such as surface air temperature, snow depth, and vegetation cover. C1 Observ Paris, CNRS, LERMA, F-75014 Paris, France. Columbia Univ, Dept Appl Phys, NASA, Goddard Inst Space Studies, New York, NY 10027 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Prigent, C (reprint author), Observ Paris, CNRS, LERMA, 61 Ave Observatoire, F-75014 Paris, France. RI Rossow, William/F-3138-2015 NR 41 TC 11 Z9 11 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 MAR PY 2003 VL 42 IS 3 BP 368 EP 380 DI 10.1175/1520-0450(2003)042<0368:ROSAAG>2.0.CO;2 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 648XJ UT WOS:000181176200002 ER PT J AU Jacobson, KC Arkoosh, MR Kagley, AN Clemons, ER Collier, TK Casillas, E AF Jacobson, KC Arkoosh, MR Kagley, AN Clemons, ER Collier, TK Casillas, E TI Cumulative effects of natural and anthropogenic stress on immune function and disease resistance in juvenile chinook salmon SO JOURNAL OF AQUATIC ANIMAL HEALTH LA English DT Article ID BACTERIAL KIDNEY-DISEASE; EUBOTHRIUM-SALVELINI CESTODA; ONCORHYNCHUS-TSHAWYTSCHA; RENIBACTERIUM-SALMONINARUM; POLYCHLORINATED-BIPHENYLS; INCREASED SUSCEPTIBILITY; SOCKEYE SALMON; SEAWATER; FISH; PSEUDOPHYLLIDEA AB Previous studies have shown that juvenile chinook salmon Oncorhynchus tshawytscha exposed in the field or the laboratory to polychlorinated biphenyls (PCBs), an anthropogenic stressor, are immunosuppressed. It is not known whether simultaneous exposure to natural stressors can increase this immunosuppression. To examine the effects of natural and anthropogenic stressors on immune function, we infected juvenile chinook salmon with metacereariae of the trematode Nanophyetus salmincola by exposing the fish to infected freshwater snails Juga plicifera. Infected (>300 metacercatiae per fish) and noninfected salmon were then injected with either the commercial PCB mixture Aroclor 1254 or an acetone-emulphor carrier. B cell function was examined by in vitro hemolytic plaque-forming cell (PFC) assay. Nanophyetus salmincola infection resulted in significantly lower anterior kidney primary PFCs and lower splenic secondary PFCs. The combination of N. salmincola infection and Aroclor 1254 exposure caused a lower anterior kidney primary PFC response than did either stressor alone. The immune function of juvenile chinook salmon was also measured by challenging them with the marine bacterium Listonella anguillarum (formerly known as Vibrio anguillarum). Fish infected with N. salmincola had higher mortalities than noninfected fish when challenged with L. anguillarum. These experiments demonstrated that N. salmincola infection in juvenile chinook salmon can impair immune function and disease resistance. The findings also show that in combination these natural and anthropogenic stressors can have a greater negative effect on salmon health than either stressor alone. C1 NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Fish Ecol Div, Newport, OR 97365 USA. NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Environm Conservat Div, Newport, OR 97365 USA. NOAA, Natl Marine Fisheries Serv, NW Fisheries Ctr, Environm Conservat Div, Seattle, WA 98112 USA. NOAA, Natl Marine Fisheries Serv, NW Fisheries Ctr, Fish Ecol Div, Seattle, WA 98112 USA. RP Jacobson, KC (reprint author), NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Fish Ecol Div, Newport, OR 97365 USA. NR 46 TC 30 Z9 30 U1 2 U2 11 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE SUITE 110, BETHESDA, MD 20814-2199 USA SN 0899-7659 J9 J AQUAT ANIM HEALTH JI J. Aquat. Anim. Health PD MAR PY 2003 VL 15 IS 1 BP 1 EP 12 DI 10.1577/1548-8667(2003)015<0001:CEONAA>2.0.CO;2 PG 12 WC Fisheries; Veterinary Sciences SC Fisheries; Veterinary Sciences GA 685VK UT WOS:000183284200001 ER PT J AU Lyu, CH Barnes, WL AF Lyu, CH Barnes, WL TI Four years of TRMM/VIRS on-orbit calibrations and characterization using lunar models and data from Terra/MODIS SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID BIDIRECTIONAL REFLECTANCE SPECTROSCOPY; METEOROLOGICAL SATELLITE IMAGERS; INFRARED SCANNER; RAPID CALIBRATION; CHANNELS AB Four years of on-orbit solar calibration data have been used to quantify the temporal degradation of the two reflected solar bands of the Visible and Infrared Scanner (VIRS) aboard the Tropical Rainfall Measuring Mission (TRMM) satellite. Solar calibrations, performed using an onboard solar diffuser, show no significant changes in the VIRS 1.61-mum data. The responsivity (digital counts per radiance unit) of the 0.62-mum band has changed and, as a function of days since 1998, is given by R-1 (day) 5 69.782 - 0.0022 x day, with an annual degradation of 1.15%. Four years of on-orbit lunar measurements were also examined in an attempt to quantify any degradation in the solar diffuser. The integrated lunar reflectance with phase angles ranging from 1.6degrees to 106degrees were fit with the lunar photometric model of Hapke. A good fit was made to the 0.62-mum data, but overall, the quality of the data did not support efforts to quantify any diffuser degradation. The quality of the VIRS radiometry was also examined by comparing data from the five VIRS spectral bands with similar Terra/Moderate Resolution Imaging Spectroradiometer (MODIS) bands while viewing near-coincident nadir scenes. The median reflectance differences, VIRS - MODIS, are -1.4% and -12.1% for the solar bands (VIRS 0.62 and 1.61 mum; MODIS 0.65 and 1.64 mum). The median brightness temperature differences for the thermal bands at 3.78, 10.83, and 12.03 mum, respectively, are -0.53, 0.04, and -0.76 K. These values compare well with the values from Minnis et al. The large difference in the 1.61-mum bands and day-night differences in the thermal emissive bands are discussed. C1 NASA, Lab Hydrospher Proc, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, GEST, Caelum Res Corp, Goddard Space Flight Ctr, Greenbelt, MD USA. RP Barnes, WL (reprint author), NASA, Lab Hydrospher Proc, Goddard Space Flight Ctr, Code 970, Greenbelt, MD 20771 USA. NR 14 TC 13 Z9 13 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD MAR PY 2003 VL 20 IS 3 BP 333 EP 347 DI 10.1175/1520-0426(2003)020<0333:FYOTVO>2.0.CO;2 PG 15 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 648XF UT WOS:000181175900001 ER PT J AU Bucsela, E Morrill, J Heavner, M Siefring, C Berg, S Hampton, D Moudry, D Wescott, E Sentman, D AF Bucsela, E Morrill, J Heavner, M Siefring, C Berg, S Hampton, D Moudry, D Wescott, E Sentman, D TI N-2(B-3 Pi(g)) and N-2(+)(A(2) Pi(u)) vibrational distributions observed 2 in sprites SO JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS LA English DT Article; Proceedings Paper CT Conference on Sprites, Elves and Their Global Activities CY SEP 10, 2002 CL FRANKFURT, GERMANY DE red sprites; ionized N-2; 1PG and Meinel spectra; vibrational distributions ID PHOTOMETRIC MEASUREMENTS; POPULATIONS; IONIZATION; EXCITATION; EMISSIONS; THUNDERSTORMS; DAYGLOW; ELVES; N-2+; N2 AB A pair of spectra taken simultaneously by two different ground-based instruments has been analyzed by our group. As with previous observations, the spectra are composed primarily of the N-2 first positive group (1PG) (B(3)Pi(g) - A(3)Sigma(u)(+)). In a previous study, we compared the N-2(B) vibrational distributions from the spectral analysis with those resulting from a time-dependent kinetic model of N-2 triplet excited state populations. Both spectra reflect emission between 50 and 60 km. The higher-attitude spectrum is primarily 1PG but also shows the presence of features which appear to be N-2(+) Meinel (A(2) Pi(u) - X(2)Sigma(g)(+)). The lower-attitude spectrum shows little or none of the apparent Meinel emission but has an N-2(B) vibrational distribution similar to ones observed in laboratory afterglows. In this paper we discuss the apparent presence of the Meinel emission and present the observed N-2(B) vibrational distributions. (C) 2003 Elsevier Science Ltd. All rights reserved. C1 Goddard Earth Sci & Technol Ctr, Baltimore, MD USA. USN, Res Lab, EO Hulburt Ctr Space Res, Washington, DC 20375 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. USN, Res Lab, Div Plasma Phys, Washington, DC 20375 USA. Computat Phys Inc, Springfield, VA USA. Ball Aerosp & Technol Corp, Boulder, CO USA. Univ Alaska, Inst Geophys, Fairbanks, AL USA. RP Bucsela, E (reprint author), Goddard Earth Sci & Technol Ctr, Baltimore, MD USA. NR 36 TC 40 Z9 40 U1 0 U2 1 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 MAR PY 2003 VL 65 IS 5 BP 583 EP 590 DI 10.1016/S1364-6826(02)00316-4 PG 8 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA 676GU UT WOS:000182743600013 ER PT J AU Shie, CL Tao, WK Simpson, J Sui, CH AF Shie, CL Tao, WK Simpson, J Sui, CH TI Quasi-equilibrium states in the tropics simulated by a cloud-resolving model. Part I: Specific features and budget analysis SO JOURNAL OF CLIMATE LA English DT Article ID RADIATIVE-CONVECTIVE EQUILIBRIUM; MESOSCALE PROCESSES; WATER; SENSITIVITY; PRECIPITATION; MIDLATITUDE; DYNAMICS; CLUSTERS; MOISTURE; CLIMATE AB A series of long-term integrations using the two-dimensional Goddard Cumulus Ensemble (GCE) model were performed with various imposed environmental components. Vertical wind shear, minimum surface wind speed (only used for computing surface fluxes), and radiation are found to be the three major components that determine the quasi-equilibrium temperature and water vapor fields simulated in this study. The genesis of a warm/wet quasi-equilibrium state is mainly due to either strong vertical wind shear along with strong surface winds or large surface fluxes, while a colder/drier quasi-equilibrium state is due to weak (mixed wind) shear along with weak surface winds. Latent heat flux and net large-scale temperature forcing dominate the beginning stages of the simulated convective systems, then considerably weaken in the final stages leading to quasi-equilibrium states. Radiation is necessary in establishing the quasi-equilibrium states but is not crucial to the considerable variation between them. A warmer/wetter thermodynamic state is found to produce more rainfall, as convective clouds are the leading source of rainfall over stratiform clouds even though they occupy much less area. Convective clouds are more likely to occur in the presence of strong surface winds (latent heat flux), while stratiform clouds (especially the well-organized type) are favored in conditions with strong wind shear (net large-scale forcing). The convective systems, which consist of distinct cloud types due to the variation in horizontal winds, are also found to propagate differently. Convective systems with mixed-wind shear generally propagate in the direction of shear, while systems with strong, multidirectional wind shear propagate in a more complex way. Cloud-scale eddies are found to transfer the heat and moisture vertically and assist in balancing the heat (Q1) and moisture (Q2) budgets and in reaching a quasi-equilibrium state. Atmospheric stability, CAPE, and mass fluxes are also investigated and compared between the various quasi-equilibrium states. C1 NASA, Goddard Space Flight Ctr, Mesoscale Atmospher Proc Branch, Atmospheres Lab, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. RP Shie, CL (reprint author), NASA, Goddard Space Flight Ctr, Mesoscale Atmospher Proc Branch, Atmospheres Lab, Code 912, Greenbelt, MD 20771 USA. OI SUI, CHUNG-HSIUNG/0000-0003-2842-5660 NR 29 TC 22 Z9 23 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD MAR PY 2003 VL 16 IS 5 BP 817 EP 833 DI 10.1175/1520-0442(2003)016<0817:QESITT>2.0.CO;2 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 645FJ UT WOS:000180965300003 ER PT J AU Zhu, S Li, C Su, CH Lin, B Ban, H Scripa, RN Lehoczky, SL AF Zhu, S Li, C Su, CH Lin, B Ban, H Scripa, RN Lehoczky, SL TI Thermal diffusivity, thermal conductivity, and specific heat capacity measurements of molten tellurium SO JOURNAL OF CRYSTAL GROWTH LA English DT Article; Proceedings Paper CT 14th American Conference on Crystal Growth and Epitaxy CY AUG 04-09, 2002 CL SEATTLE, WASHINGTON SP Amer Assoc Crystal Growth, Amer Chem Soc, Journal Crystal Growth & Design, Coherent Crystal Associates, Crystal Syst Inc, Engelhard Clal LP, Eichem Inc, Haraus, Mat Technol Div, Johnson Matthey Corp, Thermal Technol Inc, Toyo Tanso USA Inc, Vesuvius McDanel, Zicar Ceramics Inc, Shopley Metalorgan, Pillar Ind, Rath Performance Fibers DE diffusion; heat transfer; semicoducting materials ID ALLOYS AB Temperature transient curves of molten tellurium have been measured by a laser flash method in the temperature range from 773 to 1173 K. The thermal diffusivity was calculated from the temperature transient caused by the laser pulse. Numerical fittings of the data were used to obtain both the thermal conductivity and specific heat as functions of temperature. The temperature-dependent specific heat results agree well with the previous published data. The thermal diffusivity and conductivity indicate a structure change in the liquid phase. (C) 2002 Published by Elsevier Science B.V. C1 NASA, George C Marshall Space Flight Ctr, Space Sci Lab, USRA, Huntsville, AL 35812 USA. Univ Alabama, Sch Engn, Birmingham, AL 35294 USA. NASA, George C Marshall Space Flight Ctr, Sci Directorate, Micrograv Sci & Applicat Dept, Huntsville, AL 35812 USA. RP Zhu, S (reprint author), NASA, George C Marshall Space Flight Ctr, Space Sci Lab, USRA, SD47, Huntsville, AL 35812 USA. RI Ban, Heng/I-6268-2012 NR 11 TC 8 Z9 11 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD MAR PY 2003 VL 250 IS 1-2 BP 269 EP 273 DI 10.1016/S0022-0248(02)02250-9 PG 5 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA 652HE UT WOS:000181373100046 ER PT J AU Cooper, LP AF Cooper, LP TI A research agenda to reduce risk in new product development through knowledge management: a practitioner perspective SO JOURNAL OF ENGINEERING AND TECHNOLOGY MANAGEMENT LA English DT Article DE risk; new product development; innovation; knowledge management ID RESEARCH-AND-DEVELOPMENT; CROSS-FUNCTIONAL TEAMS; PERFORMANCE; INNOVATION; SUCCESS; DESIGN; COMMUNICATION; UNCERTAINTY; CONFLICT; SYSTEMS AB Successful new product development (NPD) requires effective strategies for reducing risk. Knowledge management systems (KMS) have the potential to aid in risk reduction, e.g. by gathering and processing relevant information and encapsulated knowledge from a variety of internal and external sources. The potential benefits of KMS, however, have not been fully realized, and may actually introduce new risks. This paper presents a practioner view of the desired characteristics of tools to support NPD and suggests a research agenda for the use of knowledge-based tools from the perspective of balancing benefits and risks. (C) 2003 Elsevier Science B.V. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Cooper, LP (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 302-231, Pasadena, CA 91109 USA. RI Wang, Charles/B-5565-2011 OI Wang, Charles/0000-0001-9331-8437 NR 72 TC 78 Z9 81 U1 6 U2 37 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0923-4748 J9 J ENG TECHNOL MANAGE JI J. Eng. Technol. Manage. PD MAR-JUN PY 2003 VL 20 IS 1-2 BP 117 EP 140 DI 10.1016/S0923-4748(03)00007-9 PG 24 WC Business; Engineering, Industrial; Management SC Business & Economics; Engineering GA 674HL UT WOS:000182631300006 ER PT J AU Dansby, MA Bovell-Benjamin, AC AF Dansby, MA Bovell-Benjamin, AC TI Sensory characterization of a ready-to-eat sweetpotato breakfast cereal by descriptive analysis SO JOURNAL OF FOOD SCIENCE LA English DT Article DE sweetpotato flour; descriptive analysis; ready-to-eat breakfast cereals; sensory evaluation; sweetpotato ID EXTRUSION-COOKING; QUALITY; FLOUR; STORAGE AB The sweetpotato [Ipomoea batatas (L.) Lam], an important industry in the United States, has been selected as a candidate crop to be grown on future long-duration space missions by NASA. Raw sweetpotato roots were processed into flour, which was used to formulate ready-to-eat breakfast cereal (RTEBC). Twelve trained panelists evaluated the sensory attributes of the extruded RTEBC using descriptive analysis. The samples were significantly different (P < 0.05) for all attributes. Twelve perceived sensory attributes, which could be used to differentiate the appearance, texture, and flavor of sweetpotato RTEBC, were described. The data could be used to optimize the RTEBC and for designing studies to test its consumer acceptance. C1 Tuskegee Univ, NASA, Tuskegee Ctr Environm Syst & Human Explorat Space, Dept Nutr & Food Sci, Tuskegee, AL 36088 USA. RP Bovell-Benjamin, AC (reprint author), Tuskegee Univ, NASA, Tuskegee Ctr Environm Syst & Human Explorat Space, Dept Nutr & Food Sci, Tuskegee, AL 36088 USA. NR 29 TC 7 Z9 11 U1 0 U2 8 PU INST FOOD TECHNOLOGISTS PI CHICAGO PA 525 WEST VAN BUREN, STE 1000, CHICAGO, IL 60607-3814 USA SN 0022-1147 J9 J FOOD SCI JI J. Food Sci. PD MAR PY 2003 VL 68 IS 2 BP 706 EP 709 DI 10.1111/j.1365-2621.2003.tb05736.x PG 4 WC Food Science & Technology SC Food Science & Technology GA 714JN UT WOS:000184910300050 PM 14974490 ER PT J AU Markley, FL AF Markley, FL TI Attitude error representations for Kalman filtering SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article ID SPACECRAFT ATTITUDE; VECTOR OBSERVATIONS; DYNAMICS AB The quaternion has the lowest dimensionality possible for a globally nonsingular attitude representation. The quaternion must obey a unit norm constraint, though,which has led to the development of an extended Kalman filter using a quaternion for the global attitude estimate and a three-component representation for attitude errors. Various attitude error representations are considered for this multiplicative extended Kalman filter, which incorporates a nonlinear, norm preserving quaternion reset operation. Second-order bias corrections are computed in this framework. C1 NASA, Goddard Space Flight Ctr, Guidance Navigat & Control Syst Engn Branch, Greenbelt, MD 20771 USA. RP Markley, FL (reprint author), NASA, Goddard Space Flight Ctr, Guidance Navigat & Control Syst Engn Branch, Code 571, Greenbelt, MD 20771 USA. NR 39 TC 177 Z9 203 U1 4 U2 13 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD MAR-APR PY 2003 VL 26 IS 2 BP 311 EP 317 DI 10.2514/2.5048 PG 7 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 653QN UT WOS:000181448500014 ER PT J AU Morelli, EA AF Morelli, EA TI Low-order equivalent system identification for the Tu-144LL supersonic transport aircraft SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article AB Low-order equivalent system models were identified from flight-test data for the TV-144LL supersonic transport aircraft. Flight-test maneuvers were executed by Russian and American test pilots flying the aircraft from Zhukovsky airfield outside Moscow, Russia. Flight tests included longitudinal and lateral/directional maneuvers at supersonic cruise flight conditions. Piloted frequency sweeps and multistep maneuvers were used to generate data for closed-loop low-order equivalent system modeling.. Parameters in these models were estimated using a high-accuracy Fourier transform with selectable frequency capability and an equation-error/output-error (EE/OE) formulation in the frequency domain. Results were compared to parameter estimates obtained using spectral estimation and subsequent least-squares fit to frequency response data used for Bode plots, as implemented in the commercial software package CIFER(R). Modeling results from the two, methods agreed well for both a frequency sweep and multiple concatenated multistep maneuvers. For a single multistep maneuver, only the EE/OE method gave an adequate model fit with good prediction capability. Closed-loop low-order equivalent system identification results for the Tu-144LL at several different flight conditions were computed and tabulated. C1 NASA, Langley Res Ctr, Dynam & Control Branch, Hampton, VA 23681 USA. RP Morelli, EA (reprint author), NASA, Langley Res Ctr, Dynam & Control Branch, MS 132, Hampton, VA 23681 USA. NR 17 TC 8 Z9 9 U1 2 U2 6 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD MAR-APR PY 2003 VL 26 IS 2 BP 354 EP 362 DI 10.2514/2.5053 PG 9 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 653QN UT WOS:000181448500019 ER PT J AU Kim, YS Mesbahi, M Hadaegh, FY AF Kim, YS Mesbahi, M Hadaegh, FY TI Dual-spacecraft formation flying in deep space: Optimal collision-free reconfigurations SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article ID COORDINATION; RESOLUTION C1 Univ Washington, Dept Aeronaut & Astronaut, Seattle, WA 98195 USA. CALTECH, Jet Prop Lab, Auton & Control Sect, Pasadena, CA 91109 USA. RP Kim, YS (reprint author), Univ Washington, Dept Aeronaut & Astronaut, Box 352400, Seattle, WA 98195 USA. NR 16 TC 19 Z9 19 U1 0 U2 3 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD MAR-APR PY 2003 VL 26 IS 2 BP 375 EP 379 DI 10.2514/2.5059 PG 5 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 653QN UT WOS:000181448500024 ER PT J AU Grenon, SM Sheynberg, N Hurwitz, S Xiao, X Ehrman, M Cohen, RJ Williams, GH AF Grenon, SM Sheynberg, N Hurwitz, S Xiao, X Ehrman, M Cohen, RJ Williams, GH TI The effect of a constant high salt diet on the renal, cardio-endocrine and cardiovascular responses to simulated microgravity. SO JOURNAL OF INVESTIGATIVE MEDICINE LA English DT Meeting Abstract CT Clinical Research 2003 Meeting CY MAR 13-16, 2003 CL BALTIMORE, MARYLAND C1 Harvard Univ, Massachusetts Gen Hosp, Sch Med,Dept Med, Div Endocrinol, Boston, MA USA. McGill Univ, Div Cardiothorac Surg, Montreal, PQ, Canada. MIT, NASA, Ctr Quantat Cardiovasc Physiol Modeling & Data An, Harvard MIT Div Hlth Sci & Technol, Cambridge, MA 02139 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU B C DECKER INC PI HAMILTON PA 20 HUGHSON ST SOUTH, PO BOX 620, L C D 1, HAMILTON, ONTARIO L8N 3K7, CANADA SN 1081-5589 J9 J INVEST MED JI J. Invest. Med. PD MAR PY 2003 VL 51 SU 2 BP S377 EP S377 PG 1 WC Medicine, General & Internal; Medicine, Research & Experimental SC General & Internal Medicine; Research & Experimental Medicine GA 652QW UT WOS:000181390700125 ER PT J AU Sierhuis, M Clancey, WJ Seah, C Trimble, JP Sims, MH AF Sierhuis, M Clancey, WJ Seah, C Trimble, JP Sims, MH TI Modeling and simulation for mission operations work system design SO JOURNAL OF MANAGEMENT INFORMATION SYSTEMS LA English DT Article DE agent languages; business process modeling; mission operations design; multiagent simulation; work practices AB Work system analysis and design is complex and nondeterministic. In this paper we describe Brahms, a multiagent modeling and simulation environment for designing complex interactions in human-machine systems. Brahms was originally conceived as a business process design tool that simulates work practices, including social systems of work. We describe our modeling and simulation method for mission operations work systems design, based on a research case study in which we used Brahms to design mission operations for a proposed discovery mission to the Moon. We then describe the results of an actual method application project-the Brahms Mars Exploration Rover. Space mission operations are similar to operations of traditional organizations; we show that the application of Brahms for space mission operations design is relevant and transferable to other types of business processes in organizations. C1 Univ W Florida, Inst Human & Machine Cognit, Pensacola, FL 32514 USA. NASA, Ames Res Ctr, Computat Sci Div, Moffett Field, CA 94035 USA. Sci Applicat Int Corp, Mclean, VA 22102 USA. NR 30 TC 7 Z9 7 U1 0 U2 4 PU M E SHARPE INC PI ARMONK PA 80 BUSINESS PARK DR, ARMONK, NY 10504 USA SN 0742-1222 J9 J MANAGE INFORM SYST JI J. Manage. Inform. Syst. PD SPR PY 2003 VL 19 IS 4 BP 85 EP 128 PG 44 WC Computer Science, Information Systems; Information Science & Library Science; Management SC Computer Science; Information Science & Library Science; Business & Economics GA 658AV UT WOS:000181700200005 ER PT J AU Venkateswaran, K Hattori, N La Duc, MT Kern, R AF Venkateswaran, K Hattori, N La Duc, MT Kern, R TI ATP as a biomarker of viable microorganisms in clean-room facilities SO JOURNAL OF MICROBIOLOGICAL METHODS LA English DT Article DE ATP; microbial detection; 16S rDNA; clean-rooms; viable but noncultivable ID PHYLOGENETIC ANALYSIS; BIOLUMINESCENCE; ASSAY; DIVERSITY; VIBRIO AB A new firefly luciferase bioluminescence assay method that differentiates free extracellular ATP (dead cells, etc.) from intracellular ATP (viable microbes) was used to determine the viable microbial cleanliness of various clean-room facilities. For comparison, samples were taken from both clean-rooms, where the air was filtered to remove particles >0.5 gm, and ordinary rooms with unfiltered air. The intracellular ATP was determined after enzymatically degrading the sample's free ATR Also for comparison, cultivable microbial populations were counted on nutrient-rich trypticase soy agar (TSA) plates. Both the cultivable and ATP-based determinations indicate that the microbial burden was lower in clean-room facilities than in ordinary rooms. However, there was no direct correlation between the two sets of measurements because the two assays measured very different populations. A large fraction of the samples yielded no colony formers on TSA, but were positive for intracellular ATP. Subsequently, genomic DNA was isolated directly from selected samples and 16S rDNA fragments were cloned and sequenced, identifying nearest neighbors, many of which are known to be noncultivable in the media employed. It was concluded that viable microbial contamination can be reliably monitored by measurement of intracellular ATP, and that this method may be considered superior to cultivable colony counts due to its speed and its ability to report the presence of viable but noncultivable organisms. When the detection of nonviable microbes is of interest, the ATP assay can be supplemented with DNA analysis. (C) 2002 Elsevier Science B.V. All rights reserved. C1 CALTECH, Jet Prop Lab, Biotechnol & Planetary Protect Grp, Pasadena, CA 91109 USA. Kikkoman Foods Inc, Noda, Chiba, Japan. RP Venkateswaran, K (reprint author), CALTECH, Jet Prop Lab, Biotechnol & Planetary Protect Grp, Mail Stop 89,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 29 TC 106 Z9 112 U1 0 U2 22 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-7012 J9 J MICROBIOL METH JI J. Microbiol. Methods PD MAR PY 2003 VL 52 IS 3 BP 367 EP 377 AR PII S0167-7012(02)00192-6 DI 10.1016/S0167-7012(02)00192-6 PG 11 WC Biochemical Research Methods; Microbiology SC Biochemistry & Molecular Biology; Microbiology GA 640FT UT WOS:000180678300011 PM 12531506 ER PT J AU Gallimore, SD Jacobsen, LS O'Brien, WF Schetz, JA AF Gallimore, SD Jacobsen, LS O'Brien, WF Schetz, JA TI Operational sensitivities of an integrated scramjet ignition/fuel-injection system SO JOURNAL OF PROPULSION AND POWER LA English DT Article ID PLASMA TORCH AB Results are presented of experiments conducted in a supersonic wind tunnel on an integrated fuel-injection/ignition system, consisting of an aeroramp injector and a plasma-torch igniter. The main goals of the work were to determine how the lifting effect of the aeroramp affected the plasma jet, to ascertain how the injection of fuel through the aeroramp and the power supplied to the torch influenced the distributions of excited species downstream of the device, and to investigate any synergistic effects from the combination. The aeroramp was observed to have a strong lifting effect on the plasma jet, especially for injector momentum-flux ratios above 1.5. In addition, increases in the torch input power produced an exponential effect on the emission intensity of the excited-state species downstream of the plasma jet, but was not observed to influence the jet penetration height. The results demonstrate that the increased penetration of combustion enhancing radicals is largely a function of the fluidic mechanisms generated by the injector and, thus, aids the plasma torch in influencing the combustion kinetics farther into the freestream than would normally be possible. C1 Virginia Polytech Inst & State Univ, Dept Mech Engn, Blacksburg, VA 24061 USA. Virginia Polytech Inst & State Univ, Dept Aerosp & Ocean Engn, Blacksburg, VA 24061 USA. RP Gallimore, SD (reprint author), NASA, Langley Res Ctr, Hyperson Air Breathing Prop Branch, Mail Stop 168, Hampton, VA 23681 USA. NR 15 TC 13 Z9 14 U1 1 U2 6 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD MAR-APR PY 2003 VL 19 IS 2 BP 183 EP 189 DI 10.2514/2.6116 PG 7 WC Engineering, Aerospace SC Engineering GA 656GX UT WOS:000181579400003 ER PT J AU Seraji, H AF Seraji, H TI New traversabillity indices and traversabillity grid for integrated sensor/map-based navigation SO JOURNAL OF ROBOTIC SYSTEMS LA English DT Article ID TERRAIN-BASED NAVIGATION AB This paper presents new measures of terrain traversability at short range and long range of a mobile robot; namely, local and global traversability indices. The sensor-based local traversability index is related by a set of linguistic rules to large obstacles and surface softness within a short range of the robot measured by on-board sensors. The map-based global traversability index is obtained from the terrain topographic map, and is based on major surface features such as hills and lakes within a long range of the robot. These traversability indices complement the mid-range sensor-based regional traversability index introduced earlier. Each traversabilitv index is represented by four fuzzy sets with the linguistic labels {POOR, LOW, MODERATE, HIGH}, corresponding to surfaces that are unsafe, moderately-unsafe, moderately-safe, and safe for traversal, respectively. The global terrain analysis also leads to the new concepts of traversability map and traversability grid for representation of terrain quality based on the global map information. The traversabilitv indices are used in two sensor-based traverse-local and traverse-regional behaviors and one map-based traverse-global behavior. These behaviors are integrated with a map-based seek-goal behavior to ensure that the mobile robot reaches its goal safely while avoiding both sensed and mapped terrain hazards. This provides a unified system in which the two independent sources of terrain quality information, i.e., prior maps and on-board sensors, are integrated together for reactive robot navigation. The paper is concluded by a graphical simulation study. (C) 2003 Wiley Periodicals, Inc. C1 NASA, Jet Propuls Lab, CALTECH, Pasadena, CA 91109 USA. RP Seraji, H (reprint author), NASA, Jet Propuls Lab, CALTECH, Pasadena, CA 91109 USA. NR 18 TC 14 Z9 14 U1 0 U2 1 PU JOHN WILEY & SONS INC PI HOBOKEN PA 111 RIVER ST, HOBOKEN, NJ 07030 USA SN 0741-2223 J9 J ROBOTIC SYST JI J. Robot. Syst. PD MAR PY 2003 VL 20 IS 3 BP 121 EP 134 DI 10.1002/rob.10074 PG 14 WC Robotics SC Robotics GA 650ZP UT WOS:000181295000002 ER PT J AU Venkataraman, S Lamberti, L Haftka, RT Johnson, TF AF Venkataraman, S Lamberti, L Haftka, RT Johnson, TF TI Challenges in comparing numerical solutions for optimum weights of stiffened shells SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article ID COMBINED INPLANE LOADS; DESIGN; PANELS; COMPOSITE; PROGRAM; IMPERFECT; PANDA2 AB Optimizations of stiffened shells with different stiffener shapes performed to rank and identify the optimum designs during the preliminary design trade studies require a large number of analyses and hence rely on the use of efficient but approximate analysis methods. In the design of shells, the treatment of imperfections on buckling loads and stresses is of paramount importance. It is demonstrated how conservativeness of the approximate analyses used in buckling load calculation, the number of variables optimized (design freedom), and nonstructural constraints influence the "eight of optimum designs. This demonstration is based on the results of a trade study performed to compare minimum weight designs of stiffened shells optimized under stress and buckling constraints for a reusable launch vehicle tank. PANDA2 was selected for the present study because it uses approximate analysis procedures that permit the many thousands of structural analyses needed for global optimization and it also has sophisticated machinery for generating imperfections and accounting for their effects. Optimum weights were influenced not only by material choice, number of optimization variables, and manufacturing constraints, but also by the analysis model conservativeness. Optimization of shells with effect of initial imperfections exhibited substantial weight differences between different stiffened-shell concepts, partly because of conservativeness in the analysis. C1 San Diego State Univ, Dept Aerosp Engn, San Diego, CA 92182 USA. Politecn Bari, Dipartimento Progettaz & Ingn Meccan & Gest, I-10126 Bari, Italy. Univ Florida, Dept Mech & Aerosp Engn, Gainesville, FL 32611 USA. NASA, Langley Res Ctr, Aerosp Technol, Mech & Durabil Branch, Hampton, VA 23681 USA. RP Venkataraman, S (reprint author), San Diego State Univ, Dept Aerosp Engn, San Diego, CA 92182 USA. NR 31 TC 12 Z9 12 U1 0 U2 3 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAR-APR PY 2003 VL 40 IS 2 BP 183 EP 192 DI 10.2514/2.3952 PG 10 WC Engineering, Aerospace SC Engineering GA 664NU UT WOS:000182067800005 ER PT J AU Lee, TK Zhong, XL Gong, L Quinn, R AF Lee, TK Zhong, XL Gong, L Quinn, R TI Hypersonic aerodynamic heating prediction using weighted essentially nonoscillatory schemes SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article ID EFFICIENT IMPLEMENTATION; EQUATIONS; EULER C1 Univ Calif Los Angeles, Dept Mech & Aerosp Engn, Los Angeles, CA 90095 USA. NASA, Dryden Flight Res Ctr, Engn & Tech Serv, Edwards AFB, CA 93523 USA. Analyt Serv & Mat Inc, Aerostruct Branch, Hampton, VA 23666 USA. RP Lee, TK (reprint author), Univ Calif Los Angeles, Dept Mech & Aerosp Engn, Los Angeles, CA 90095 USA. NR 13 TC 1 Z9 1 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAR-APR PY 2003 VL 40 IS 2 BP 294 EP 298 DI 10.2514/2.3946 PG 5 WC Engineering, Aerospace SC Engineering GA 664NU UT WOS:000182067800019 ER PT J AU Mikellides, IG Mandell, MJ Katz, I AF Mikellides, IG Mandell, MJ Katz, I TI Stagnation-point density of hypersonic ions in a repelling plasma sheath SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article ID WAKES C1 Sci Applicat Int Corp, Def Technol Grp, San Diego, CA 92121 USA. CALTECH, Jet Prop Lab, Adv Prop Technol Grp, Thermal & Prop Engn Sect, Pasadena, CA 91109 USA. RP Mikellides, IG (reprint author), Sci Applicat Int Corp, Def Technol Grp, 9455 Towne Ctr Dr,Mail Stop W2076, San Diego, CA 92121 USA. NR 10 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 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAR-APR PY 2003 VL 40 IS 2 BP 298 EP 301 DI 10.2514/2.3948 PG 4 WC Engineering, Aerospace SC Engineering GA 664NU UT WOS:000182067800020 ER PT J AU Kenderian, S Berndt, TP Green, RE Djordjevic, BB AF Kenderian, S Berndt, TP Green, RE Djordjevic, BB TI Ultrasonic attenuation and velocity in pearlitic rail steel during fatigue using longitudinal wave probing SO JOURNAL OF TESTING AND EVALUATION LA English DT Article DE ultrasound; acoustic attenuation; acoustic velocity; fatigue; microcracks; dislocations; pearlite ID ROLLING-CONTACT FATIGUE; LIFE AB A computer-controlled narrowband ultrasonic pulser/receiver system was used to determine changes in the coefficient of attenuation and the acoustic velocity in pearlitic steel specimens during reverse bending fatigue. The specimens were interrogated through their length, in a direction normal to the loading and crack formation planes, using longitudinal wave bursts at 5 MHz. The ultrasonic data are compared with microscopic observations of microcracks in the fatigue-damaged zone and the fractured surfaces. The pattern in which attenuation evolves with respect to fatigue life is found to be sensitive to the onset of microcracks but appears to be unaffected by the magnitude of fatigue load, number of cracks causing failure, prior low-load fatigue history, or the hardness of the specimen. The change in velocity is found to be more pronounced during the early stages of fatigue than during the more advanced stages. It appears to be insensitive to microcracks but sensitive to stress accumulation and dislocation pileup. C1 Johns Hopkins Univ, Ctr Nondestruct Evaluat, Baltimore, MD 21211 USA. Johns Hopkins Univ, Dept Mat Sci & Engn, Baltimore, MD 21218 USA. NASA, Langley Res Ctr, Nondestruct Evaluat Sci Branch, Hampton, VA 23681 USA. RP Kenderian, S (reprint author), Johns Hopkins Univ, Ctr Nondestruct Evaluat, 810 Wyman Pk Dr,Suite G010, Baltimore, MD 21211 USA. NR 30 TC 6 Z9 6 U1 1 U2 3 PU AMER SOC TESTING MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DR, W CONSHOHOCKEN, PA 19428-2959 USA SN 0090-3973 J9 J TEST EVAL JI J. Test. Eval. PD MAR PY 2003 VL 31 IS 2 BP 98 EP 105 PG 8 WC Materials Science, Characterization & Testing SC Materials Science GA 649UF UT WOS:000181225800002 ER PT J AU Rozendaal, MA Rossow, WB AF Rozendaal, MA Rossow, WB TI Characterizing some of the influences of the general circulation on subtropical marine boundary layer clouds SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID SURFACE OBSERVATIONS; DIURNAL-VARIATIONS; OPTICAL-THICKNESS; TROPICAL PACIFIC; VERTICAL MOTION; LANDSAT IMAGERY; CLIMATE MODELS; STRATUS CLOUDS; ISCCP DATA; PART-I AB The seasonal and intraseasonal variability of boundary layer cloud in the subtropical eastern oceans is studied using combined data from the International Satellite Cloud Climatology Project and the European Centre for Medium-Range Weather Forecasts reanalysis. Spectral analysis reveals that most of the time variability of cloud properties occurs on seasonal to annual timescales. The variance decreases by one to two orders of magnitude for each decade of timescale decrease, indicating that daily to monthly timescales and their spatial extent have smaller, although nonnegligible, variability. The length of these dominant timescales suggests that the majority of the variability is influenced by the general circulation and its interaction with boundary layer turbulence, rather than being a product of local boundary layer turbulence alone. Although the dominance of seasonal to annual periods in the temporal power spectra of low-cloud fraction-TAU and CTP-justifies the previous focus of effort on seasonal variability, intraseasonal data can be better used to examine the cloud formation/dissipation processes as revealed in relationships between synoptic meteorology and cloud properties. Previous datasets have lacked the necessary combination of resolution and scope in either time or space coverage to properly characterize variability on synoptic and larger scales; this is remedied by using global satellite-retrieved cloud properties. The intraseasonal subtropical cloud variability in both hemispheres and in different seasons are characterized. In addition to cloud fraction, variability of cloud optical thickness and cloud-top pressure frequency distributions are examined. The intraseasonal variability is divided into three types. The first type, found in the Californian local summer and Southern Hemisphere regions year round, is characterized by lower-altitude, greater optical thickness, stationary clouds. The second type is found in the Canarian local summer and has more instances of smaller cloud-top pressures and a westward propagation direction. The third type, found in Northern Hemisphere regions during winter, is similar to the second type, but shows an eastward propagation direction. This study focuses on the third type more closely and finds it to be associated with the lower sea level pressure, upward vertical velocity phase of synoptic waves. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Columbia Univ, Program Earth & Environm Sci, New York, NY USA. RP NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. EM wrossow@giss.nasa.gov RI Rossow, William/F-3138-2015 NR 73 TC 16 Z9 16 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 EI 1520-0469 J9 J ATMOS SCI JI J. Atmos. Sci. PD MAR PY 2003 VL 60 IS 5 BP 711 EP 728 DI 10.1175/1520-0469(2003)060<0711:CSOTIO>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 646QX UT WOS:000181046700002 ER PT J AU Lyapustin, AI AF Lyapustin, AI TI Interpolation and profile correction (IPC) method for shortwave radiative transfer in spectral intervals of gaseous absorption SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID OXYGEN-A-BAND; NONHOMOGENEOUS ATMOSPHERES; SCATTERING; SURFACE AB The new interpolation and profile correction (IPC) method for radiance/flux calculations in gaseous absorption bands is presented. The IPC method is designed to allow an arbitrary spectral resolution including monochromatic mode. It features a high computational efficiency typical of the correlated-k method, and an accuracy comparable to that of the line-by-line codes. The IPC method may be considered as a variant of the spectral mapping techniques powerfully enhanced by a straightforward correction of the solution for single and multiple scattering. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Baltimore, MD 21228 USA. RP Lyapustin, AI (reprint author), NASA, Goddard Space Flight Ctr, Mail Code 920, Greenbelt, MD 20771 USA. RI Lyapustin, Alexei/H-9924-2014 OI Lyapustin, Alexei/0000-0003-1105-5739 NR 17 TC 11 Z9 11 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD MAR PY 2003 VL 60 IS 6 BP 865 EP 871 DI 10.1175/1520-0469(2003)060<0865:IAPCIM>2.0.CO;2 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 646QZ UT WOS:000181046900006 ER PT J AU Launius, RD AF Launius, RD TI Planes, trains, and automobiles: Choosing transportation modes in the 20th-century American West SO JOURNAL OF THE WEST LA English DT Article C1 NASA, Washington, DC USA. RP Launius, RD (reprint author), NASA, Washington, DC USA. NR 66 TC 0 Z9 0 U1 0 U2 0 PU J WEST INC PI MANHATTAN PA P O BOX 1009, MANHATTAN, KS 66505-1009 USA SN 0022-5169 J9 J WEST JI J. West PD SPR PY 2003 VL 42 IS 2 BP 45 EP 55 PG 11 WC History SC History GA 673MZ UT WOS:000182585900006 ER PT J AU DellaCorte, C AF DellaCorte, C TI Wanted: Change... applicants sought SO LUBRICATION ENGINEERING LA English DT Editorial Material C1 NASA, Glenn Res Ctr, Ames, IA USA. RP DellaCorte, C (reprint author), NASA, Glenn Res Ctr, Ames, IA 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 MAR PY 2003 VL 59 IS 3 BP 3 EP 3 PG 1 WC Engineering, Mechanical SC Engineering GA 664EQ UT WOS:000182049100001 ER PT J AU Abdul-Aziz, A Baaklini, G Bhatt, R AF Abdul-Aziz, A Baaklini, G Bhatt, R TI Nondestructive testing of ceramic matrix composites coupled with finite element analyses SO MATERIALS EVALUATION LA English DT Article DE finite element analysis; computed topography; ceramic matrix composites; stress analysis; nondestructive testing AB Ceramic matrix composites are engineered materials frequently filled with manufacturing discontinuities, such as voids, delamination or fiber cracking. In this paper, nondestructive testing (NDT) of a ceramic matrix composite tensile specimen is coupled with a finite element analysis to locate the failure location prior to the actual testing. The tensile ceramic matrix composite specimen is scanned with computed tomography along various planes. The majority of the observed discontinuities are porosities in the matrix. ne computed tomography images are then used to reconstruct a three dimensional volume of the specimen's gage section using an image processing software. Subsequently, a three dimensional finite element analysis is carried out to include the scanned porosities. The stress variations along the scanned computed tomography planes are determined and comparison,of the finite element analysis results with those extracted via NDT and the test data are reported. C1 Cleveland State Univ, Dept Civil Engn, NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. USA, Aviat Syst Command, NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NASA, Glenn Res Ctr, Life Predict Branch, Cleveland, OH 44135 USA. RP Abdul-Aziz, A (reprint author), Cleveland State Univ, Dept Civil Engn, NASA, Glenn Res Ctr, 21000 Brookpk Rd,MS 6-1, Cleveland, OH 44135 USA. NR 5 TC 1 Z9 1 U1 0 U2 0 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 MAR PY 2003 VL 61 IS 3 BP 413 EP 417 PG 5 WC Materials Science, Characterization & Testing SC Materials Science GA 652QD UT WOS:000181389100007 ER PT J AU Mickens, T Schulz, M Sundaresan, M Ghoshal, A Naser, AS Reichmeider, R AF Mickens, T Schulz, M Sundaresan, M Ghoshal, A Naser, AS Reichmeider, R TI Structural health monitoring of an aircraft joint SO MECHANICAL SYSTEMS AND SIGNAL PROCESSING LA English DT Article AB A major concern with ageing aircraft is the deterioration of structural components in the form of fatigue cracks at fastener holes, loose rivets and debonding of joints. These faults in conjunction with corrosion can lead to multiple-site damage and pose a hazard to flight. Developing a simple vibration-based method of damage detection for monitoring ageing structures is considered in this paper. The method is intended to detect damage during operation of the vehicle before the damage can propagate and cause catastrophic failure of aircraft components. It is typical that only a limited number of sensors could be used on the structure and damage can occur anywhere on the surface or inside the structure. The research performed was to investigate use of the chirp vibration responses of an aircraft wing tip to detect, locate and approximately quantify damage. The technique uses four piezoelectric patches alternatively as actuators and sensors to send and receive vibration diagnostic signals. Loosening of selected screws simulated damage to the wing tip. The results obtained from the testing led to the concept of a sensor tape to detect damage at joints in an aircraft structure. (C) 2003 Elsevier Science Ltd. All rights reserved. C1 N Carolina Agr & Tech State Univ, Dept Mech Engn, Intelligent Struct & Mech Lab, Greensboro, NC 27411 USA. NASA, Langley Res Ctr, Lockheed Martin, Hampton, VA 23681 USA. Natl Instruments, Raleigh, NC 27609 USA. RP Mickens, T (reprint author), N Carolina Agr & Tech State Univ, Dept Mech Engn, Intelligent Struct & Mech Lab, Greensboro, NC 27411 USA. EM schulz@ncat.edu NR 11 TC 31 Z9 37 U1 0 U2 11 PU ACADEMIC PRESS LTD ELSEVIER SCIENCE LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0888-3270 J9 MECH SYST SIGNAL PR JI Mech. Syst. Signal Proc. PD MAR PY 2003 VL 17 IS 2 BP 285 EP 303 DI 10.1006/mssp.2001.1425 PG 19 WC Engineering, Mechanical SC Engineering GA 658PK UT WOS:000181729200003 ER PT J AU Dixon, ET Bogard, DD Garrison, DH AF Dixon, ET Bogard, DD Garrison, DH TI Ar-39-Ar-40 chronology of R chondrites SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID EQUILIBRATED ORDINARY CHONDRITES; PARENT BODY; THERMAL HISTORIES; CARLISLE LAKES; EXPOSURE AGES; METEORITES; RUMURUTI; CLASSIFICATION; FRAGMENTATION; METAMORPHISM AB This study presents the first determinations of Ar-39-Ar-40 ages of R chondrites for the purpose of understanding the thermal history of the R chondrite parent body. The Ar-39-Ar-40 ages were determined on whole-rock samples of four R chondrites: Carlisle Lakes, Rumuruti, Acfer 217, and Pecora Escarpment #91002 (PCA 91002). All samples are breccias except for Carlisle Lakes. The age spectra are complicated by recoil and diffusive loss to various extents. The peak Ar-39-Ar-40 ages of the four chondrites are greater than or equal to4.35, similar to4.47 +/- 0.02, 4.30 +/- 0.07 Ga, and greater than or equal to4.37 Ga, respectively. These ages are similar to Ar-Ar ages of relatively unshocked ordinary chondrites (4.52-4.38 Ga) and are older than Ar-Ar ages of most shocked ordinary chondrites (much less than4.2 Ga). Because the meteorites with the oldest (Rumuruti, similar to4.47 Ga) and the youngest (Acfer 217, similar to4.30 Ga) ages are both breccias, these ages probably do not record slow cooling within an undisrupted asteroidal parent body. Instead, the process of breccia formation may have differentially reset the ages of the constituent material, or the differences in their age spectra may arise from mixtures of material that had different ages. Two end-member type situations may be envisioned to explain the age range observed in the R chondrites. The first is if the impact(s) that reset the ages of Acfer 217 and Rumuruti was very early. In this case, the similar to170 Ma maximum age difference between these meteorites may have been produced by much deeper burial of Acfer 217 than Rumuruti within an impact-induced thick regolith layer, or within a rubble pile type parent body following parent body re-assembly. The second, preferred scenario is if the impact that reset the age of Acfer 217 was much later than that which reset Rumuruti, then Acfer 217 may have cooled more rapidly within a much thinner regolith layer. In either scenario, the oldest age obtained here, from Rumuruti, provides evidence for relatively early (similar to4.47 Ga) impact events and breccia formation on the R chondrite parent body. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Los Alamos Natl Lab, C INC, MSJ514, Los Alamos, NM 87545 USA. EM edixon@lanl.gov NR 54 TC 14 Z9 14 U1 0 U2 0 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 1086-9379 EI 1945-5100 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD MAR PY 2003 VL 38 IS 3 BP 341 EP 355 PG 15 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 731DC UT WOS:000185868400002 ER PT J AU Kletetschka, G Kohout, T Wasilewski, PJ AF Kletetschka, G Kohout, T Wasilewski, PJ TI Magnetic remanence in the Murchison meteorite SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID AMINO-ACIDS; THERMOREMANENT MAGNETIZATION; CARBONACEOUS CHONDRITES; FIELD; DISCHARGES; HEMATITE AB The Murchison meteorite is a carbonaceous chondrite containing a small amount of chondrules, various inclusions, and matrix with occasional porphyroblasts of olivine and/or pyroxene. It also contains amino acids that may have served as the necessary components for the origin of life. Magnetic analyses of Murchison identify an ultrasoft magnetic component due to superparamagnetism as a significant part of the magnetic remanence. The rest of the remanence may be due to electric discharge in the form of lightning bolts that may have formed the amino acids. The level of magnetic remanence does not support this possibility and points to a minimum ambient field of the remanence acquisition. We support our observation by showing that normalized mineral magnetic acquisition properties establish a calibration curve suitable for rough paleofield determination. When using this approach, 1-2% of the natural remanence left in terrestrial rocks with TRM and/or CRM determines the geomagnetic field intensity irrespective of grain size or type of magnetic mineral (with the exception of hematite). The same method is applied to the Murchison meteorite where the measured meteorite remanence determines the paleofield minimum intensity of 200-2000 nT during and/or after the formation of the parent body. C1 Howard Univ, Washington, DC 20059 USA. NASA, Goddard Space Flight Ctr, Astrochem Branch, Greenbelt, MD 20771 USA. Charles Univ, Fac Nat Sci, Prague, Czech Republic. Acad Sci Czech Republ, Inst Geol, Prague, Czech Republic. RP Kletetschka, G (reprint author), Howard Univ, Washington, DC 20059 USA. RI Kletetschka, Gunther/C-9996-2011; Kohout, Tomas/C-1394-2008 OI Kletetschka, Gunther/0000-0002-0645-9037; Kohout, Tomas/0000-0003-4458-3650 NR 28 TC 30 Z9 31 U1 0 U2 11 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 MAR PY 2003 VL 38 IS 3 BP 399 EP 405 PG 7 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 731DC UT WOS:000185868400007 ER PT J AU Roush, TL AF Roush, TL TI Estimated optical constants of the Tagish Lake meteorite SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID BIDIRECTIONAL REFLECTANCE SPECTROSCOPY; PHYSICAL STATE; IRON CONTENT; MU-M; SURFACE; SPECTRA; ICE; CRYSTALLINE; CARBONATES; CALLISTO AB The visible, near-infrared, and mid-infrared (0.3-25 mum) real and imaginary indices of refraction are derived from reflectance measurements of the Tagish Lake meteorite. These are compared to some real and imaginary indices of refraction of the individual minerals composing the Tagish Lake meteorite. From this comparison, it is clear that the imaginary indices of several individual minerals contribute to the estimated imaginary index of this meteorite. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Roush, TL (reprint author), NASA, Ames Res Ctr, MS 245-3, Moffett Field, CA 94035 USA. EM troush@mail.arc.nasa.gov NR 57 TC 13 Z9 13 U1 1 U2 2 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD MAR PY 2003 VL 38 IS 3 BP 419 EP 426 PG 8 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 731DC UT WOS:000185868400009 ER PT J AU Delaney, MP AF Delaney, MP TI Effects of temperature and turbulence on the predator-prey interactions between a heterotrophic flagellate and a marine bacterium SO MICROBIAL ECOLOGY LA English DT Article ID SMALL-SCALE TURBULENCE; PELAGIC FOOD WEBS; ENCOUNTER RATES; FLUID MOTION; PARTICLES; PLANKTON; SIZE AB Biotic and abiotic factors can influence interactions between microbial grazers and their prey, thus impacting both the cycling of biogenic carbon within the surface layer of the ocean and the export of carbon to the deep ocean and higher trophic levels. In this study, microcosm experiments were used to evaluate the combined effect of temperature and turbulence on the growth rate of a marine bacterium (Vibrio splendidus), a protistan predator (Paraphysomonas sp.), and the community grazing impact of Paraphysomonas sp. on V. splendidus. It was found that the artificial turbulence generated (1.35 X 10(-1) cm(2) s(-3)) significantly increased the rates of growth of Paraphysomonas sp. at high (>10degreesC), but not low (<5degreesC) temperatures, and that turbulence had no effect on the growth of V. splendidus. Both flagellate and bacterial growth were temperature dependent and decreased 4- to 6-fold as temperatures decreased from 15 to 0degreesC. Bacterial grazing mortality by Paraphysomonas sp. was 1.3- to 2.5-fold greater in the turbulent than static treatments among all four temperatures, and the rates of cell-specific ingestion of bacteria by Paraphysomonas sp. was 2-fold greater at 15 and 10degreesC in the turbulent than in the static treatment. Hence, this study shows that turbulence can influence nanoflagellate grazing at temperatures >5degreesC and suggests that at low temperatures, increased viscosity may limit the size of organisms that can be affected by small-scale turbulence. C1 Mem Univ Newfoundland, Ctr Ocean Sci, St Johns, NF A1C 5S7, Canada. RP Delaney, MP (reprint author), NASA, Goddard Space Flight Ctr, Goddard Earth Sci Technol Ctr, Mail Code 900-1, Greenbelt, MD 20771 USA. NR 38 TC 14 Z9 17 U1 1 U2 17 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0095-3628 J9 MICROBIAL ECOL JI Microb. Ecol. PD MAR PY 2003 VL 45 IS 3 BP 218 EP 225 DI 10.1007/s00248-002-1058-4 PG 8 WC Ecology; Marine & Freshwater Biology; Microbiology SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Microbiology GA 675CX UT WOS:000182676400002 PM 12658520 ER PT J AU Young, RE AF Young, RE TI The Galileo probe: how it has changed our understanding of Jupiter SO NEW ASTRONOMY REVIEWS LA English DT Review DE Jupiter; planets : probes ID NORTH EQUATORIAL BELT; TROPOSPHERIC GAS-COMPOSITION; DEEP ZONAL WINDS; HELIUM ABUNDANCE; GIANT PLANETS; JOVIAN ATMOSPHERE; VOYAGER MEASUREMENTS; THERMAL STRUCTURE; CLOUD STRUCTURE; OUTER PLANETS AB The Galileo Mission to Jupiter, which arrived in December 1995, provided the first study by an orbiter, and the first in-situ sampling via an entry probe, of an outer planet atmosphere. The rationale for an entry probe is that, even from an orbiter, remote sensing of the Jovian atmosphere could not adequately retrieve the information desired. This paper provides a current summary of the most significant aspects of the data returned from the Galileo entry probe. As a result of the probe measurements, there has been a reassessment of our understanding of outer planet formation and evolution of the solar system. The primary scientific objective of the Galileo probe was to determine the composition of the Jovian atmosphere, which from remote sensing remained either very uncertain, or completely unknown, with respect to several key elements. The probe found that the global He mass fraction is significantly above the value reported from the Voyager Jupiter flybys but is slightly below the protosolar value, implying that there has been some settling of He to the deep Jovian interior. The probe He measurements have also led to a reevaluation of the Voyager He mass fraction for Saturn, which is now determined to be much closer to that of Jupiter. The elements C, N, S, Ar, Kr, Xe were all found to have global abundances approximately three times their respective solar abundances. This result has raised a number of fundamental issues with regard to proper-ties of planetesimals and the solar nebula at the time of giant planet formation. Ne, on the other hand, was found to be highly depleted, probably as a result of it being carried along with helium as helium settles towards the deep interior. The global abundance of 0 was not obtained by the probe because of the influence of local processes at the probe entry site (PES), processes which depleted condensible species, in this case H(2)O, well below condensation levels. Other condensible species, namely NH(3) and H(2)S, were similarly affected but attained their deep equilibrium mixing ratios before the maximum depth sampled by the probe. Processes that might be capable of producing such effects on the condensibles are still under investigation. Measured isotopic ratios of noble gases and other heavy elements are solar, and (D+(3)He)/H is the same to within measurement uncertainties as in the local interstellar medium. No thick clouds were detected, and in particular no significant water cloud, but the PES location clearly affected the probe measurements of clouds. In fact, the probe data must be understood in the context of the location of the PES, which was within what is termed a 5 micron hot spot, a local clearing in the clouds that is bright near the 5 mum spectral region. The thermal structure at the PES was determined from approximately 1000 km above the 1 bar pressure level (10(-9) bars) to 132 km below 1 bar (22 bars). The probe showed the atmosphere to have a generally sub-adiabatic temperature gradient (static stability) of approximate to0.1 K km(-1) to as deep as the probe made measurements. In the upper atmosphere the probe derived a maximum positive vertical temperature gradient of approximately 5 K km(-1), and maximum temperature of approximate to900 K. The energy sources producing the warm upper atmosphere have yet to be completely identified. At first glance, Doppler tracking of the probe indicates that the long observed cloud level zonal winds extend to levels at least as deep as the probe made measurements. Zonal wind increases from approximate to80 ms(-1) at pressures less than a bar to about 180 ms(-1) near 5 bars, and remains approximately constant with depth thereafter. However, there is a question as to whether the winds measured from probe tracking are representative of the general wind field, or are considerably influenced by localized winds associated with the PES. Published by Elsevier Science B.V. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Young, RE (reprint author), NASA, Ames Res Ctr, M-S 245-3, Moffett Field, CA 94035 USA. EM richard.e.young@nasa.gov NR 184 TC 38 Z9 38 U1 1 U2 7 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 1387-6473 J9 NEW ASTRON REV JI New Astron. Rev. PD MAR PY 2003 VL 47 IS 1 BP 1 EP 51 DI 10.1016/S1387-6473(02)00272-5 PG 51 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 662UM UT WOS:000181967300001 ER PT J AU Singh, SN Brenner, M AF Singh, SN Brenner, M TI Limit cycle oscillation and orbital stability in aeroelastic systems with torsional nonlinearity SO NONLINEAR DYNAMICS LA English DT Article DE aeroelastic system; describing function; limit cycle oscillation; orbital stability; flutter ID OUTPUT-FEEDBACK CONTROL; STRUCTURAL NONLINEARITIES; WING SECTION; FLUTTER; AIRFOIL AB The paper treats the question of the existence of limit cycle oscillations of prototypical aeroelastic wing sections with structural nonlinearity using the describing function method. The chosen dynamic model describes the nonlinear plunge and pitch motion of a wing. The model includes an asymmetric structural nonlinearity in the pitch degree-of-freedom. The dual-input describing functions of the nonlinearity are derived for the limit cycle analysis. Analytical expressions for the average value, and the amplitude and frequency of oscillation of pitch and plunge responses are obtained. Based on an analytical approach as well as the Nyquist criterion, stability of the limit cycles is examined. Numerical results are presented for a set of values of the flow velocities and the locations of the elastic axis which show that the predicted limit cycle oscillation amplitude and frequency as well as the mean value are quite close to the actual values. Furthermore, for the chosen model with linear aerodynamics, it is seen that the amplitude of the pitch limit cycle oscillation does not always increase with the flow velocity for certain elastic axis locations. C1 Univ Nevada, Dept Elect & Comp Engn, Las Vegas, NV 89154 USA. NASA, Aerostruct Branch, Dryden Flight Res Ctr, Edwards AFB, CA 93523 USA. RP Singh, SN (reprint author), Univ Nevada, Dept Elect & Comp Engn, Las Vegas, NV 89154 USA. NR 27 TC 15 Z9 18 U1 0 U2 4 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0924-090X J9 NONLINEAR DYNAM JI Nonlinear Dyn. PD MAR PY 2003 VL 31 IS 4 BP 435 EP 450 DI 10.1023/A:1023264319167 PG 16 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA 664PR UT WOS:000182069900005 ER PT J AU Nelson, R Parker, G Hom, M AF Nelson, R Parker, G Hom, M TI A portable airborne laser system for forest inventory SO PHOTOGRAMMETRIC ENGINEERING AND REMOTE SENSING LA English DT Article ID STAND CHARACTERISTICS; CANOPY STRUCTURE; SCANNER DATA; BASAL AREA; LIDAR; VOLUME; BIOMASS; ALTIMETER; HEIGHT AB A simple, lightweight, inexpensive, portable airborne laser profiling system has been assembled from off-the-shelf, commercially available components. The system, which costs approximately $30,000, is designed to fly aboard small helicopters and single- or twin-engine high-wing aircraft without airframe modification, The system acquires first-return range and amplitude measurements at data rates up to 2000 hz (operator-con trolled) and has an operational envelope up to 300 m above terrain. The airborne laser profiling system includes the laser transmitter/receiver, differential GPS receiver, a CCD video camera and recorder, and a laptop computer which interleaves and records the GPS and laser range/amplitude data. The portable airborne laser system (PALS) was designed to acquire forest height measurements along linear flight transects in order to conduct regional or subcontinental forest inventories worldwide. This economical laser system now puts airborne laser mensuration within reach of operational foresters and researchers interested in making rapid forest structure and/or timber surveys in remote areas. PALS has been used to acquire over 5000 km of flight transect data over the state of Delaware. C1 NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Sci Syst & Applicat Inc, Greenbelt, MD 20771 USA. Smithsonian Environm Res Ctr, Edgewater, MD 21037 USA. RP Nelson, R (reprint author), NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Sci Syst & Applicat Inc, Code 923, Greenbelt, MD 20771 USA. EM ross@ltpmail.gsfc.nasa.gov; parker@serc.si.edu; mhom@pop900.gsfc.nasa.gov RI Nelson, Ross/H-8266-2014; OI Parker, Geoffrey/0000-0001-7055-6491 NR 28 TC 51 Z9 51 U1 1 U2 3 PU AMER SOC PHOTOGRAMMETRY PI BETHESDA PA 5410 GROSVENOR LANE SUITE 210, BETHESDA, MD 20814-2160 USA SN 0099-1112 J9 PHOTOGRAMM ENG REM S JI Photogramm. Eng. Remote Sens. PD MAR PY 2003 VL 69 IS 3 BP 267 EP 273 PG 7 WC Geography, Physical; Geosciences, Multidisciplinary; Remote Sensing; Imaging Science & Photographic Technology SC Physical Geography; Geology; Remote Sensing; Imaging Science & Photographic Technology GA 817QU UT WOS:000221192800004 ER PT J AU Berdichevsky, DB Lepping, RP Farrugia, CJ AF Berdichevsky, DB Lepping, RP Farrugia, CJ TI Geometric considerations of the evolution of magnetic flux ropes SO PHYSICAL REVIEW E LA English DT Article ID CORONAL MASS EJECTIONS; SIMULATIONS; SYSTEMS; CLOUDS; FIELDS AB We use flux conservation and magnetohydrodynamics (MHD) theory to discuss essential differences in the nature of the evolution of two analytical solutions describing magnetic flux tubes evolving in time. The first of these maintains the elongation of the tube, while the second maintains a constant angular extension with respect to a possible pointlike source. In the first case, free expansion of the plasma (density N) occurs only in a direction perpendicular to the flux-tube x axis. In the second case, isotropic evolution is considered. In both cases it is assumed that at initial time t(0) the flux-tube B field is the force-free magnetostatic Lundquist solution, which energetically corresponds to the most stable state for any flux-tube structure. We show that for each case conservation of magnetic flux is enough to establish the scaling with time of the B field. While both expansions may correspond to the evolution of observed flux tubes in the heliosphere, the isotropic expansion appears to capture consistently essential features associated with the actual observations of expanding coronal mass ejections within 30 solar radii. For isotropic expansion of the plasma the force-free nature of the B field is preserved for all time. As an example the MHD solutions are applied to an interplanetary magnetic cloud observed with the spacecraft Wind, which passed Earth's vicinity on June 2, 1998. C1 L3 Commun EER Syst Inc, Largo, MD 20774 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ New Hampshire, Ctr Space Sci, Durham, NH 03824 USA. RP Berdichevsky, DB (reprint author), L3 Commun EER Syst Inc, Largo, MD 20774 USA. NR 45 TC 32 Z9 32 U1 0 U2 1 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 MAR PY 2003 VL 67 IS 3 AR 036405 DI 10.1103/PhysRevE.67.036405 PN 2 PG 8 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 663TB UT WOS:000182020900051 PM 12689169 ER PT J AU Luo, LS Girimaji, SS AF Luo, LS Girimaji, SS TI Theory of the lattice Boltzmann method: Two-fluid model for binary mixtures SO PHYSICAL REVIEW E LA English DT Article ID NAVIER-STOKES EQUATION; SPINODAL DECOMPOSITION; NONIDEAL GASES; PARTICULATE SUSPENSIONS; NUMERICAL SIMULATIONS; FLUID MIXTURES; KINETIC-THEORY; LIQUID-GAS; FLOWS; DIFFUSION AB A two-fluid lattice Boltzmann model for binary mixtures is developed. The model is derived formally from kinetic theory by discretizing two-fluid Boltzmann equations in which mutual collisions and self-collisions are treated independently. In the resulting lattice Boltzmann model, viscosity and diffusion coefficients can be varied independently by a suitable choice of mutual- and self-collision relaxation-time scales. Further, the proposed model can simulate miscible and immiscible fluids by changing the sign of the mutual-collision term. This is in contrast to most existing single-fluid lattice Boltzmann models that employ a single-relaxation-time scale and hence are restricted to unity Prandtl and Schmidt numbers. The extension of binary mixing model to multiscalar mixing is quite straightforward. C1 NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. Texas A&M Univ, Dept Aerosp Engn, College Stn, TX 77843 USA. RP Luo, LS (reprint author), Natl Inst Aerosp, 144 Res Dr, Hampton, VA 23666 USA. EM luo@NIAnet.org; girimaji@aero.tamu.edu RI Luo, Li-Shi/A-4561-2011 OI Luo, Li-Shi/0000-0003-1215-7892 NR 66 TC 112 Z9 116 U1 2 U2 25 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 MAR PY 2003 VL 67 IS 3 AR 036302 DI 10.1103/PhysRevE.67.036302 PN 2 PG 11 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 663TB UT WOS:000182020900042 PM 12689160 ER PT J AU Hudy, LM Naguib, AM Humphreys, WM AF Hudy, LM Naguib, AM Humphreys, WM TI Wall-pressure-array measurements beneath a separating/reattaching flow region SO PHYSICS OF FLUIDS LA English DT Article ID TURBULENT SEPARATION BUBBLE; BACKWARD-FACING STEP; REATTACHING FLOW; PASSIVE CONTROL; REVERSE FLOW; SHEAR-LAYER; FLUCTUATIONS; BEHAVIOR AB A database of wall-pressure-array measurements was compiled for studying the space-time character of the surface-pressure field within a separating/reattaching flow region. The experimental setup consisted of a long splitter plate located within the wake of a fence and instrumented with an array of flush-mounted microphones. Data were acquired for a Reynolds number of 7900, based on the fence height above the splitter plate. Two distinctive regions, defined based on their location relative to the position of the mean reattachment point (x(r)) of the shear layer, emerged from this investigation. Upstream, from the fence to 0.25x(r), the surface-pressure signature was dominated by large time scale disturbances and an upstream convection velocity of 0.21U(infinity). Beyond 0.25x(r), turbulent structures with smaller time scales and a downstream convection velocity of 0.57U(infinity) generated most of the pressure fluctuations. Interestingly, the low-frequency wall-pressure signature typically associated with the flapping of the separated shear layer was found to be composed of standing and downstream/upstream propagating wave components. The latter seemed to originate from a point near the middle of the reattachment zone, suggesting the existence of an absolute instability of the recirculation bubble, which may be the cause of the flapping of the shear layer. (C) 2003 American Institute of Physics. C1 Michigan State Univ, Dept Mech Engn, E Lansing, MI 48824 USA. NASA, Langley Res Ctr, Adv Measurement & Diagnost Branch, Hampton, VA 23681 USA. RP Naguib, AM (reprint author), Michigan State Univ, Dept Mech Engn, E Lansing, MI 48824 USA. NR 23 TC 59 Z9 61 U1 0 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 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD MAR PY 2003 VL 15 IS 3 BP 706 EP 717 DI 10.1063/1.1540633 PG 12 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 644DQ UT WOS:000180903000014 ER PT J AU Zent, AP Quinn, RC Grunthaner, FJ Hecht, MH Buehler, MG McKay, CP Ricco, AJ AF Zent, AP Quinn, RC Grunthaner, FJ Hecht, MH Buehler, MG McKay, CP Ricco, AJ TI Mars atmospheric oxidant sensor (MAOS): an in-situ heterogeneous chemistry analysis SO PLANETARY AND SPACE SCIENCE LA English DT Article DE Mars; oxidant; sensor; peroxide ID MARTIAN SOIL; LIFE; SEARCH; ECOSYSTEMS; REACTIVITY; METEORITE; PEROXIDE; CLAYS; MODEL AB We describe a chemometric array sensor, the Mars atmospheric oxidant sensor (MAOS, pronounced "mouse") that is designed to measure the oxidation rate of thin films on the martian surface. We select films that are sensitive to particular types of oxidants, that represent key elements in the martian soil, or that emulate prebiotic materials. Concern that naturally arising martian oxidants may have destroyed evidence of ancient life on Mars was raised by the Viking mission in the 1970s. The possibility that oxidants may limit the viability of biological habitats is particularly timely in the light of recent suggestions of contemporary flowing water on Mars. By controlling the temperature of the films, as well as their exposure to dust and ultraviolet light, MAOS will discriminate among leading hypotheses for oxidant production. MAOS weighs 55 g, fits in a 6 x 7 x 2 cm(3) envelope, and used 250 mW power. Much of the enabling technology was developed for the MOx experiment, lost on the Russian Mars '96 mission. Published by Elsevier Science Ltd. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. SETI Inst, Moffett Field, CA 94035 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. ALCARA Biosci, Mountain View, CA 94043 USA. RP Zent, AP (reprint author), NASA, Ames Res Ctr, MS 245-3, Moffett Field, CA 94035 USA. RI Ricco, Antonio/A-5273-2010; OI Ricco, Antonio/0000-0002-2355-4984 NR 44 TC 13 Z9 13 U1 0 U2 2 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 MAR PY 2003 VL 51 IS 3 BP 167 EP 175 DI 10.1016/S0032-0633(02)00204-0 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 666XR UT WOS:000182202200002 ER PT J AU Miller, J Zeitlin, C Cucinotta, FA Heilbronn, L Stephens, D Wilson, JW AF Miller, J Zeitlin, C Cucinotta, FA Heilbronn, L Stephens, D Wilson, JW TI Benchmark studies of the effectiveness of structural and internal materials as radiation shielding for the International Space Station SO RADIATION RESEARCH LA English DT Article ID ENERGY-TRANSFER SPECTRA; CROSS-SECTIONS; 510-MEV/NUCLEON FE-56; DEPTH DEPENDENCE; FRAGMENTATION; POLYETHYLENE; ENVIRONMENT; TARGETS; MODELS AB Accelerator-based measurements and model calculations have been used to study the heavy-ion radiation transport properties of materials in use on the International Space Station (ISS). Samples of the ISS aluminum outer hull were augmented with various configurations of internal wall material and polyethylene. The materials were bombarded with high-energy iron ions characteristic of a significant part of the galactic cosmic-ray (GCR) heavy-ion spectrum. Transmitted primary ions and charged fragments produced in nuclear collisions in the materials were measured near the beam axis, and a model was used to extrapolate from the data to lower beam energies and to a lighter ion. For the materials and ions studied, at incident particle energies from 1037 MeV/nucleon down to at least 600 MeV/nucleon, nuclear fragmentation reduces the average dose and dose equivalent per incident ion. At energies below 400 MeV/nucleon, the calculation predicts that as material is added, increased ionization energy loss produces increases in some dosimetric quantities. These limited results suggest that the addition of modest amounts of polyethylene or similar material to the interior of the ISS will reduce the dose to ISS crews from space radiation; however, the radiation transport properties of ISS materials should be evaluated with a realistic space radiation field. (C) 2003 by Radiation Research Society. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Univ Tennessee, Dept Nucl Engn, Knoxville, TN 37996 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Miller, J (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, MS 74-197, Berkeley, CA 94720 USA. RI Heilbronn, Lawrence/J-6998-2013 OI Heilbronn, Lawrence/0000-0002-8226-1057 NR 18 TC 36 Z9 36 U1 2 U2 7 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 MAR PY 2003 VL 159 IS 3 BP 381 EP 390 DI 10.1667/0033-7587(2003)159[0381:BSOTEO]2.0.CO;2 PG 10 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA 654UE UT WOS:000181513800011 PM 12600241 ER PT J AU Dong, JR Kaufmann, RK Myneni, RB Tucker, CJ Kauppi, PE Liski, J Buermann, W Alexeyev, V Hughes, MK AF Dong, JR Kaufmann, RK Myneni, RB Tucker, CJ Kauppi, PE Liski, J Buermann, W Alexeyev, V Hughes, MK TI Remote sensing estimates of boreal and temperate forest woody biomass: carbon pools, sources, and sinks SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE forest biomass pools; sources and sinks; Kyoto Protocol; remote sensing; NDVI; forest inventory ID VEGETATION INDEX DATA; US FORESTS; LAND; ECOSYSTEMS; CLIMATE; FLUXES; BUDGET AB The relation between satellite measurements of the normalized difference vegetation index (NDVI), cumulated over the growing season, and inventory estimates of forest woody biomass carbon is estimated statistically with data from 167 provinces and states in six countries (Canada, Finland, Norway, Russia and the USA for a single time period and Sweden for two periods). Statistical tests indicate that the regression model can be used to represent the relation between forest biomass and NDVI across spatial, temporal and ecological scales for relatively long time scales. For the 1.42 billion ha of boreal and temperate forests in the Northern Hemisphere, the woody biomass carbon pools and sinks are estimated at a relatively high spatial resolution (8 x 8 km). We estimate the carbon pool to be 61 +/- 20 gigatons (10(9)) carbon (Gt C) during the late 1990s and the biomass sink to be 0.68 +/- 0.34 Gt C/year between the 1982 and 1999. The geographic detail of carbon sinks provided here can contribute to a potential monitoring program for greenhouse gas emission reduction commitments under the Kyoto Protocol. (C) 2002 Elsevier Science Inc. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Greenbelt, MD 20771 USA. Boston Univ, Dept Geog, Boston, MA 02215 USA. Univ Helsinki, Dept Limnol & Environm Protect, FIN-00014 Helsinki, Finland. European Forest Inst, FIN-80100 Joensuu, Finland. Univ Helsinki, Dept Forest Ecol, FIN-00014 Helsinki, Finland. St Petersburg Forest Ecol Ctr, St Petersburg 194021, Russia. Univ Arizona, Tree Ring Res Lab, Tucson, AZ 85721 USA. RP Dong, JR (reprint author), NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Greenbelt, MD 20771 USA. RI Hughes, Malcolm/F-3350-2014; Myneni, Ranga/F-5129-2012; Liski, Jari/O-8494-2016 OI Hughes, Malcolm/0000-0003-1062-3167; Liski, Jari/0000-0002-0847-8207 NR 35 TC 160 Z9 197 U1 9 U2 81 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 MAR PY 2003 VL 84 IS 3 BP 393 EP 410 AR PII S0034-4257(02)00130-X DI 10.1016/S0034-4257(02)00130-X PG 18 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 656CT UT WOS:000181591800006 ER PT J AU Wang, JR Manning, W AF Wang, JR Manning, W TI Near concurrent MIR, SSM/T-2, and SSM/I observations over snow-covered surfaces SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE MIR; SSM/T-2; SSM/I ID ATMOSPHERIC WATER-VAPOR; WAVE IMAGING RADIOMETER; MICROWAVE MEASUREMENTS; SEA-ICE; PARAMETERS; EMISSIVITY; RETRIEVALS; DEPTH; CLOUD AB The airborne Millimeter-wave Imaging Radiometer (MIR) and MODIS Airborne Simulator (MAS) measurements over the Arctic region and the Midwest region of the US are used to derive surface emissivities xi(nu) for three frequencies, nu = 89, 150, and 220 GHz, as well, as Normalized Difference Snow Index (NDSI) and R87 (0.87-mum reflectance). These derived parameters are compared with parameters estimated from near concurrent measurements made by the SSMI and SSM/T-2 over snow-covered areas. It is shown that the MIR-estimated xi(nu) values at nu = 89 and 150 GHz agree well with those estimated from the SSM/T-2 at nu = 91 and 150 GHz, respectively. Low MIR-estimated (v) values are generally associated with high NDSI and R87 over the snow-covered areas. Over forested areas, more fluctuations in the values of MIR-estimated xi(nu), NDSI and R87, as well as a reduction in polarization index (PI) at 37 and 85 GHz are observed. Both observations and results from radiative transfer calculations show a change in the difference between brightness temperatures (T-b) at 19 and 37 GHz, as well as PI at 37 and 85 GHz, when measured at satellite altitudes and at the surface. The amplitude of the T-b difference and PI is reduced by about 10 -- 15% from surface to high altitudes when integrated water vapor is less than or equal to 1.5 g/cm(2). This effect is readily correctable and requires consideration when validating satellite retrieval algorithms based on surface and low-elevation aircraft measurements. (C) 2002 Elsevier Science Inc. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21250 USA. RP Wang, JR (reprint author), NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. NR 24 TC 9 Z9 10 U1 1 U2 1 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 MAR PY 2003 VL 84 IS 3 BP 457 EP 470 AR PII S0034-4257(02)00134-7 DI 10.1016/S0034-4257(02)00134-7 PG 14 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 656CT UT WOS:000181591800010 ER PT J AU Feldman, JE Wilcox, JZ George, T Barsic, DN Scherer, A AF Feldman, JE Wilcox, JZ George, T Barsic, DN Scherer, A TI Elemental surface analysis at ambient pressure by electron-induced x-ray fluorescence SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB The development of a portable surface elemental analysis tool, based on the excitation of characteristic x rays from samples at ambient pressure with a focused electron beam is described. This instrument relies on the use of a thin electron transmissive membrane to isolate the vacuum of the electron source from the ambient atmosphere. The major attributes of this instrument include rapid (several minutes) spectrum acquisition, nondestructive evaluation of elemental composition, no sample preparation, and high-to-medium (several hundreds mum) spatial resolution. The instrument proof-of-principle has been demonstrated in a laboratory setup by obtaining energy dispersive x-ray spectra from metal and mineral samples. (C) 2003 American Institute of Physics. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Pasadena, CA 91125 USA. RP Feldman, JE (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 11 TC 11 Z9 11 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 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAR PY 2003 VL 74 IS 3 BP 1251 EP 1254 DI 10.1063/1.1542889 PN 1 PG 4 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 655AZ UT WOS:000181530300015 ER PT J AU Demarco, G Garces, JE Bozzolo, G AF Demarco, G Garces, JE Bozzolo, G TI Growth of Pt/Cu(100): an atomistic modeling comparison with the Pd/Cu(100) surface alloy SO SURFACE SCIENCE LA English DT Article DE adatoms; computer simulations; copper; platinum; palladium; semi-empirical models and model calculations; alloys; surface structure, morphology, roughness, and topography ID SCANNING-TUNNELING-MICROSCOPY; CU-FILMS; PT(100); METAL; RECONSTRUCTION AB The BFS method for alloys is applied to the study of Pt deposition on Cu(1 0 0). The formation of a Cu-Pt surface, alloy is discussed within the framework of previous results for Pd/Cu(1 0 0). In spite of the fact that both Pd and Pt share the same basic behavior when deposited on Cu, it is seen that subtle differences become responsible for the differences in growth observed at higher coverages. In agreement with experiment, all the main features of Pt/Cu(1 0 0) and Pd/Cu(1 0 0) are obtained by means of a simple modeling scheme, and explained in terms of a few basic ingredients that emerge from the BFS analysis. (C) 2002 Elsevier Science B.V. All rights reserved. C1 Ohio Aerosp Inst, Cleveland, OH 44142 USA. Ctr Atom Bariloche, RA-8400 San Carlos De Bariloche, Rio Negro, Argentina. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Bozzolo, G (reprint author), Ohio Aerosp Inst, 22800 Cedar Point Rd, Cleveland, OH 44142 USA. NR 19 TC 7 Z9 7 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD MAR 1 PY 2003 VL 526 IS 3 BP 309 EP 322 DI 10.1016/S0039-6028(02)02677-8 PG 14 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 649ME UT WOS:000181211900012 ER PT J AU Doarn, CR Lavrentyev, VA Orlov, OI Nicogossian, AE Grigoriev, AI Ferguson, EW Merrell, RC AF Doarn, CR Lavrentyev, VA Orlov, OI Nicogossian, AE Grigoriev, AI Ferguson, EW Merrell, RC TI Evolution of telemedicine in Russia: The influence of the Space Program on modern telemedicine programs SO TELEMEDICINE JOURNAL AND E-HEALTH LA English DT Article ID SPACEFLIGHT; SUPPORT AB Telemedicine education and application throughout Russia has its roots in Russia's space program. The concepts of telemedicine have evolved during the course of 40 years of space exploration. This paper reviews the evolution of telemedicine and the achievements of the Soviet/Russian Space Program. C1 Virginia Commonwealth Univ, Med Informat & Technol Applicat Consortium, Richmond, VA 23298 USA. Space Biomed Ctr Training & Res, Moscow, Russia. NASA Headquarters, Washington, DC USA. So Sierra Med Clin, Ridgecrest, CA USA. RP Doarn, CR (reprint author), Virginia Commonwealth Univ, Med Informat & Technol Applicat Consortium, POB 980480,1101 E Marshall St, Richmond, VA 23298 USA. NR 23 TC 7 Z9 7 U1 0 U2 0 PU MARY ANN LIEBERT INC PUBL PI LARCHMONT PA 2 MADISON AVENUE, LARCHMONT, NY 10538 USA SN 1530-5627 J9 TELEMED J E-HEALTH JI Telemed. J. e-Health PD SPR PY 2003 VL 9 IS 1 BP 103 EP 109 DI 10.1089/153056203763317710 PG 7 WC Health Care Sciences & Services SC Health Care Sciences & Services GA 655KL UT WOS:000181550900013 PM 12703503 ER PT J AU Lam, C James, JT McCluskey, R Hunter, RL AF Lam, C James, JT McCluskey, R Hunter, RL TI Pulmonary toxicity of carbon nanotubes in mice 7 and 90 days after intratracheal instillation. SO TOXICOLOGICAL SCIENCES LA English DT Meeting Abstract CT 42nd Annual Meeting of the Society-of-Toxicology CY MAR 09-13, 2003 CL SALT LAKE CITY, UTAH SP Soc Toxicol C1 Wyle Labs, Toxicol Div, Houston, TX USA. NASA Johnson Space Ctr, Space Life Sci, Houston, TX USA. Univ Texas, Ctr Med, Dept Pathol, Houston, TX USA. NR 0 TC 8 Z9 8 U1 0 U2 3 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 1096-6080 J9 TOXICOL SCI JI Toxicol. Sci. PD MAR PY 2003 VL 72 SU S MA 213 BP 44 EP 44 PG 1 WC Toxicology SC Toxicology GA 654WB UT WOS:000181518500216 ER PT J AU Meise, CJ Johnson, DL Stehlik, LL Manderson, J Shaheen, P AF Meise, CJ Johnson, DL Stehlik, LL Manderson, J Shaheen, P TI Growth rates of juvenile winter flounder under varying environmental conditions SO TRANSACTIONS OF THE AMERICAN FISHERIES SOCIETY LA English DT Article ID OF-THE-YEAR; PLAICE PLEURONECTES-PLATESSA; PSEUDOPLEURONECTES-AMERICANUS; OTOLITH MICROSTRUCTURE; FIELD OBSERVATIONS; YELLOW PERCH; WADDEN-SEA; SIZE; MORTALITY; PREDATION AB Fluctuations in juvenile winter flounder growth have been attributed to large-scale fluctuations in temperature, mesoscale fluctuations in salinity, and smaller-scale factors such as prey abundances. This study examines individual growth rates determined through otolith increment counts of free-living juvenile winter flounder during the 2000 settlement period (April 11-July 7) in Navesink River-Sandy Hook Bay estuary in New Jersey. The fish grew at highly variable rates (mean = 1.02, range = 0.25-1.91 mm/d) and did not demonstrate localized differences in growth. In addition, growth rates determined by changes in length of fish from two local areas (river and bay) were compared in the laboratory. Growth in these fish was highly variable, did not differ with location, but did decline significantly during the settlement period in the river (mean = 0.17 mm/d, range = 0.00-0.54 mm/d) and bay (mean = 0.27 mm/d, range = 0.02-0.61 mm/d). The laboratory observations supported field results of no significant differences between river and bay growth rates. General additive models were used on estuarywide field growth rates to examine their relationship with environmental variables. We found a significant positive linear relationship between growth and average water temperature and negative relationships between growth and temperature range and salinity. Food abundance showed the only curvilinear relationship with growth rate, indicating lower growth at food levels below 50 individuals/m(2). Long-term sampling was conducted to examine the effects of these early growth conditions on fall survivors. Through this sampling, it was revealed that winter flounder continued to metamorphose late into the season (July-August). By spawning over several months and having many offspring with variable growth rates, winter flounder may increase the probability of some members surviving the innate variability of a temperate estuary. C1 Natl Marine Fisheries Serv, JJ Howard Lab, Highlands, NJ 07732 USA. RP Meise, CJ (reprint author), Natl Marine Fisheries Serv, JJ Howard Lab, 74 Magruder Rd, Highlands, NJ 07732 USA. EM carol.meise@noaa.gov NR 39 TC 16 Z9 16 U1 0 U2 5 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE SUITE 110, BETHESDA, MD 20814-2199 USA SN 0002-8487 J9 T AM FISH SOC JI Trans. Am. Fish. Soc. PD MAR PY 2003 VL 132 IS 2 BP 335 EP 345 DI 10.1577/1548-8659(2003)132<0335:GROJWF>2.0.CO;2 PG 11 WC Fisheries SC Fisheries GA 658QX UT WOS:000181732900014 ER PT J AU Clifford, CWG Arnold, DH Smith, ST Pianta, M AF Clifford, CWG Arnold, DH Smith, ST Pianta, M TI Opposing views on orthogonal adaptation: a reply to Westheimer and Gee (2002) SO VISION RESEARCH LA English DT Editorial Material ID ORIENTATION DISCRIMINATION; SENSITIVITY C1 Univ Sydney, Sch Psychol, Visual Percept Unit, Sydney, NSW 2006, Australia. UCL, Dept Psychol, London WC1 6BT, England. NASA, Vis Lab, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Penn, Scheie Eye Inst, Dept Ophthalmol, Philadelphia, PA 19104 USA. RP Clifford, CWG (reprint author), Univ Sydney, Sch Psychol, Visual Percept Unit, Sydney, NSW 2006, Australia. RI Smith, Stuart/A-9037-2013; Smith, Stuart/B-8144-2011 OI Smith, Stuart/0000-0002-4735-6026; Smith, Stuart/0000-0002-4735-6026 NR 6 TC 1 Z9 1 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0042-6989 J9 VISION RES JI Vision Res. PD MAR PY 2003 VL 43 IS 6 BP 717 EP 719 DI 10.1016/S0042-6989(02)00678-8 PG 3 WC Neurosciences; Ophthalmology SC Neurosciences & Neurology; Ophthalmology GA 654TU UT WOS:000181512800011 PM 12604107 ER PT J AU Nakamura, T Noguchi, T Zolensky, ME Tanaka, M AF Nakamura, T Noguchi, T Zolensky, ME Tanaka, M TI Mineralogy and noble-gas signatures of the carbonate-rich lithology of the Tagish Lake carbonaceous chondrite: evidence for an accretionary breccia SO EARTH AND PLANETARY SCIENCE LETTERS LA English DT Article DE Tagish Lake; accretionary breccia; noble gases; mineralogy; carbonate-rich lithology ID UNEQUILIBRATED ORDINARY CHONDRITES; CM CHONDRITES; INTERPLANETARY DUST; PHASE-Q; METEORITE; HISTORY; SOLAR; MICROMETEORITES; COMPONENTS; PARTICLES AB The carbonate-rich lithology of the Tagish Lake carbonaccous chondrite was characterized by noble-gas mass spectrometry, synchrotron X-ray diffraction analysis, and transmission and scanning electron microscopy. Noble-gas analysis was performed on two samples and the results showed that primordial noble gases are abundant and solar noble gases are absent in the samples of carbonate-rich lithology. The concentrations of Ne-A2 and -E in both samples are at the maximum level observed for CI and CM chondrites, suggesting high abundances of presolar diamonds and SiC/graphite, respectively. The cosmic-ray exposure age cannot be determined precisely, because the shielding depth of our Tagish Lake samples is unknown, but the minimum exposure age was determined to be 5.5 +/- 0.7 Myr on the basis of cosmogenic (21)Ne concentrations and the highest (21)Ne production rate. X-ray and electron-microscopic study showed that the carbonate-rich lithology is dominated by loosely packed porous matrix that consists mainly of fine-grained saponite and ferromagenesian carbonate. The matrix contains very few chondrules, but many fine-grained clasts having angular shape with longest dimensions up to 1 mm. The clasts differ from host matrix in both texture and mineralogy. They are massive, compacted material with porosity much lower than matrix and contain abundant magnetite and a coherent intergrowth of serpentine and saponite that is rare in matrix. The presence of texturally and mineralogically distinct clasts indicates that the carbonate-rich lithology is a breccia, but the absence of solar noble gases and impact-induced deformational features in host matrix distinguish it from an asteroid regolith breccia. Our results instead indicate that it is an accretionary breccia formed by simultaneous accretion of diverse objects in a massive dust cloud. The clasts often enclose chondrules and anhydrous silicate fragments such as low-iron-manganese-enriched olivines. This observation and their highly compacted, angular morphology suggests that the clasts derive from earlier-formed chondritic materials which have experienced compression and fragmentation due to mild impacts and from which they were excavated and incorporated into the final rock. It is thus suggested that, in the course of planetesimal formation, agglomeration and disagglomeration of small parent bodies occurred repeatedly in a dense dust cloud where solar wind from the infant sun was shielded. The fine-grained ferromagnesian carbonates must have precipitated from aqueous solutions after the assembly of the Tagish Lake asteroid from recycled materials from previous bodies, because the carbonates coat the surfaces of pores and fill in veins in the clasts. (C) 2002 Elsevier Science B.V. All rights reserved. C1 Kyushu Univ, Fac Sci, Dept Earth & Planetary Sci, Fukuoka 8128581, Japan. Ibaraki Univ, Fac Sci, Dept Mat & Biol Sci, Mito, Ibaraki 3108512, Japan. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. High Energy Accelerator Res Org, Photon Factory Inst Mat Sci, Tsukuba, Ibaraki 3050801, Japan. RP Nakamura, T (reprint author), Kyushu Univ, Fac Sci, Dept Earth & Planetary Sci, Fukuoka 8128581, Japan. EM tomoki@geo.kyushu-u.ac.jp NR 37 TC 38 Z9 38 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0012-821X J9 EARTH PLANET SC LETT JI Earth Planet. Sci. Lett. PD FEB 28 PY 2003 VL 207 IS 1-4 BP 83 EP 101 DI 10.1016/S0012-821X(02)01127-5 PG 19 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 657JA UT WOS:000181661700007 ER PT J AU Heirtzler, JR Nazarova, K AF Heirtzler, JR Nazarova, K TI Geomagnetic secular variation in the Indian Ocean SO EARTH AND PLANETARY SCIENCE LETTERS LA English DT Article DE secular variation; Indian Ocean; marine magnetics; repeat stations; satellite magnetic measurements ID FIELD MODEL; IGRF AB Annual repeat stations in Australia and in South Africa show that secular variation may change rapidly and over short geographical distances in the Indian Ocean area. Satellite models show large secular variations in the center of the Indian Ocean where there are few island geomagnetic observatories. This paper investigates marine geomagnetic measurements to see if they give more information about secular variations in this area. Between 1960 and 1988 there were more than 70 port-to-port cruises with ships towing proton precession magnetometers in the Indian Ocean. Change in field intensity from one cruise to another provides new information about the secular variation in this part of the world. Several methods were investigated, to determine this change from the ship's data. Observing the change on closely parallel or crossing tracks provides an estimate of this change. These results indicate that there are short time and distance scales of secular variation in the Indian Ocean which have not been accounted for in geomagnetic field models. (C) 2002 Elsevier Science BN. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Raytheon ITSS Goddard Space Flight Ctr, Geodynam Branch, Greenbelt, MD 20771 USA. RP Heirtzler, JR (reprint author), NASA, Goddard Space Flight Ctr, Code 920, Greenbelt, MD 20771 USA. NR 12 TC 3 Z9 5 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0012-821X J9 EARTH PLANET SC LETT JI Earth Planet. Sci. Lett. PD FEB 28 PY 2003 VL 207 IS 1-4 BP 151 EP 158 DI 10.1016/S0012-821X(02)01128-7 PG 8 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 657JA UT WOS:000181661700012 ER PT J AU Browell, EV Hair, JW Butler, CF Grant, WB DeYoung, RJ Fenn, MA Brackett, VG Clayton, MB Brasseur, LA Harper, DB Ridley, BA Klonecki, AA Hess, PG Emmons, LK Tie, XX Atlas, EL Cantrell, CA Wimmers, AJ Blake, DR Coffey, MT Hannigan, JW Dibb, JE Talbot, RW Flocke, F Weinheimer, AJ Fried, A Wert, B Snow, JA Lefer, BL AF Browell, EV Hair, JW Butler, CF Grant, WB DeYoung, RJ Fenn, MA Brackett, VG Clayton, MB Brasseur, LA Harper, DB Ridley, BA Klonecki, AA Hess, PG Emmons, LK Tie, XX Atlas, EL Cantrell, CA Wimmers, AJ Blake, DR Coffey, MT Hannigan, JW Dibb, JE Talbot, RW Flocke, F Weinheimer, AJ Fried, A Wert, B Snow, JA Lefer, BL TI Ozone, aerosol, potential vorticity, and trace gas trends observed at high-latitudes over North America from February to May 2000 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE ozone; aerosols; springtime; Arctic; trends ID AIR-MASS CHARACTERISTICS; CHEMICAL-TRANSPORT MODEL; TROPOSPHERIC OZONE; BURNING SEASON; SOURCE REGIONS; HAZE EVENT; ARCTIC AIR; MACE HEAD; LIDAR; DISTRIBUTIONS AB [1] Ozone (O-3) and aerosol scattering ratio profiles were obtained from airborne lidar measurements on thirty-eight flights over seven deployments covering the latitudes of 40degrees-85degreesN between 4 February and 23 May 2000 as part of the Tropospheric Ozone Production about the Spring Equinox (TOPSE) field experiment. Each deployment started from Broomfield, Colorado, with bases in Churchill, Canada, and on most deployments, Thule Air Base, Greenland. Nadir and zenith lidar O-3 measurements were combined with in situ O-3 measurements to produce vertically continuous O-3 profiles from near the surface to above the tropopause. Potential vorticity (PV) distributions along the flight track were obtained from several different meteorological analyses. Ozone, aerosol, and PV distributions were used together to identify the presence of pollution plumes and stratospheric intrusions. Ozone was found to increase in the middle free troposphere (4-6 km) at high latitudes (60degrees-85degreesN) by an average of 4.6 ppbv/mo (parts per billion by volume per month) from about 54 ppbv in early February to over 72 ppbv in mid-May. The average aerosol scattering ratios at 1064 nm in the same region increased rapidly at an average rate of 0.36/mo from about 0.38 to over 1.7. Ozone and aerosol scattering were highly correlated over the entire field experiment, and PV and beryllium (Be-7) showed no significant positive trend over the same period. The primary cause of the observed O-3 increase in the mid troposphere at high latitudes was determined to be the photochemical production of O-3 in pollution plumes with less than 20% of the increase from stratospherically-derived O-3. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Sci Applicat Int Corp, Hampton, VA 23666 USA. Natl Ctr Atmospher Res, Boulder, CO 80305 USA. Univ Virginia, Dept Environm Sci, Charlottesville, VA 22904 USA. Univ Calif Irvine, Dept Chem, Irvine, CA 92697 USA. Univ New Hampshire, Inst Study Earth Oceans & Space, Durham, NH 03824 USA. Univ Rhode Isl, Grad Sch Oceanog, Kingston, RI 02881 USA. RP Browell, EV (reprint author), NASA, Langley Res Ctr, MS-401A, Hampton, VA 23681 USA. EM e.v.browell@larc.nasa.gov RI Grant, William/B-8311-2009; Atlas, Elliot/J-8171-2015; Hess, Peter/M-3145-2015; Lefer, Barry/B-5417-2012; Emmons, Louisa/R-8922-2016 OI Grant, William/0000-0002-1439-3285; Hess, Peter/0000-0003-2439-3796; Lefer, Barry/0000-0001-9520-5495; Emmons, Louisa/0000-0003-2325-6212 NR 44 TC 40 Z9 40 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 FEB 28 PY 2003 VL 108 IS D4 AR 8369 DI 10.1029/2001JD001390 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 664PJ UT WOS:000182069200002 ER PT J AU Curtis, S Adler, RF AF Curtis, S Adler, RF TI Evolution of El Nino-precipitation relationships from satellites and gauges SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE precipitation; El Nino; satellite; global ID QUANTIFYING SOUTHERN OSCILLATION; INTERANNUAL VARIABILITY; GLOBAL PRECIPITATION; ENSO; PATTERNS; CIRCULATION; ANOMALIES; DATASET; CYCLE AB [1] This study uses a 23 year (1979-2001) satellite-gauge merged community data set to further describe the relationship between El Nino-Southern Oscillation (ENSO) and precipitation. The globally complete precipitation fields reveal coherent bands of anomalies that extend from the tropics to the polar regions. El Nino-precipitation relationships were analyzed during the six strongest events from 1979 to 2001. El Ninos were defined based on the zonal contrast in rainfall in the equatorial Pacific, and seasons of precipitation evolution (pre-onset, onset, peak, decay, and postdecay) were identified. Areas with a consistent El Nino-precipitation relationship were determined based on this unique definition of El Nino and season of year. The latter analysis confirms previous studies and suggests other areas of significant signal over the oceans (Gulf of Alaska). The former analysis reveals subtle shifts in tropical rainfall from onset to decay, namely negative anomalies moving from the Maritime Continent and South Pacific to the north tropical Pacific and positive anomalies from the central equatorial Pacific southeastward. These distributions of tropical convection appear to be connected to extratropical precipitation anomalies through meridional atmospheric circulations, concentrated in the eastern Indian Ocean sector during onset and in the Pacific sector during decay. The Yangtze River basin, which is known to flood during El Nino, is affected during the entire evolution. C1 Univ Maryland Baltimore Cty, Dept Geog & Environm Syst, Joint Ctr Earth Syst Technol, NASA,Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Curtis, S (reprint author), Univ Maryland Baltimore Cty, Dept Geog & Environm Syst, Joint Ctr Earth Syst Technol, NASA,Goddard Space Flight Ctr, Code 912, Greenbelt, MD 20771 USA. EM curtis@agnes.gsfc.nasa.gov; adler@agnes.gsfc.nasa.gov RI Curtis, Scott/C-1115-2013 NR 22 TC 30 Z9 31 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD FEB 28 PY 2003 VL 108 IS D4 AR 4153 DI 10.1029/2002JD002690 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 664PJ UT WOS:000182069200012 ER PT J AU Manney, GL Froidevaux, L Santee, ML Livesey, NJ Sabutis, JL Waters, JW AF Manney, GL Froidevaux, L Santee, ML Livesey, NJ Sabutis, JL Waters, JW TI Variability of ozone loss during Arctic winter (1991-2000) estimated from UARS Microwave Limb Sounder measurements SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE Arctic ozone loss; stratosphere; ozone transport; ozone chemistry; satellite observations ID ATMOSPHERE RESEARCH SATELLITE; STRATOSPHERIC POLAR VORTEX; CHEMICAL DEPLETION; MIDDLE-ATMOSPHERE; MLS OBSERVATIONS; LOSS RATES; TRANSPORT; VALIDATION; MODEL; SIMULATIONS AB [1] A comprehensive analysis of version 5 (V5) Upper Atmosphere Research Satellite (UARS) Microwave Limb Sounder (MLS) ozone data using a Lagrangian transport (LT) model provides estimates of chemical ozone depletion for the 1991-1992 through 1997-1998 Arctic winters. These new estimates give a consistent, three-dimensional picture of ozone loss during seven Arctic winters; previous Arctic ozone loss estimates from MLS were based on various earlier data versions and were done only for late winter and only for a subset of the years observed by MLS. We find large interannual variability in the amount, timing, and patterns of ozone depletion and in the degree to which chemical loss is masked by dynamical processes. Analyses of long-lived trace gas data suggest that the LT model sometimes overestimates descent at levels above similar to520 K, so we have most confidence in the results at lower levels. When the vortex is shifted off the pole and the cold region is near the vortex edge (e.g., late winter 1993 and 1996), most rapid ozone depletion occurs near the vortex edge; when the vortex and cold region are pole-centered (e. g., late winter 1994 and 1997), most ozone loss takes place in the vortex core. MLS observed the most severe ozone depletion in 1995-1996, with about 1.3 ppmv cumulative loss for the winter at 465 K by 3 March 1996; similar to1.0 ppmv cumulative loss is seen at 465 K by mid-March 1993. Analyses of MLS data show significant ozone loss during January in most years, ranging from similar to0.3 to 0.6 ppmv at 465 K. A modified LT model used with the limited MLS data in 2000 gives rough estimates of similar to0.04 and 0.006-0.012 ppmv/day during 2-12 February and 12 February-29 March 2000, respectively, broadly consistent with other studies of the 1999-2000 winter. Estimates of depletion in MLS column ozone above 100 hPa are considerably smaller than other reported column loss estimates, primarily because many estimates include loss below 100 hPa and because MLS does not continuously observe the Arctic after early spring. Our results from analyses of MLS data confirm previous conclusions of broad overall agreement between many ozone loss estimates in the Arctic lower stratosphere near 450-480 K. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. New Mexico Highlands Univ, Sch Educ, Las Vegas, NV USA. New Mexico Highlands Univ, Dept Math Sci, Las Vegas, NV USA. New Mexico Highlands Univ, Dept Nat Sci, Las Vegas, NV USA. RP Manney, GL (reprint author), New Mexico Highlands Univ, Dept Nat Resources Management, Las Vegas, NV USA. EM manney@mls.jpl.nasa.gov NR 49 TC 38 Z9 38 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD FEB 28 PY 2003 VL 108 IS D4 AR 4149 DI 10.1029/2002JD002634 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 664PJ UT WOS:000182069200011 ER PT J AU Ruzmaikin, A Martin, S Hu, Q AF Ruzmaikin, A Martin, S Hu, Q TI Signs of magnetic helicity in interplanetary coronal mass ejections and associated prominences: Case study SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID INTER-PLANETARY SHOCK; SOLAR-WIND; ERUPTIVE PROMINENCES; FLUX ROPES; CLOUDS; FILAMENTS; FIELDS; PREDICTION; TOPOLOGY AB [1] We study the distribution of magnetic helicity in interplanetary coronal mass ejections ( CMEs) separated into magnetic clouds and remnants of the prominence structures for three cases with identified remnants of prominences. The magnetic configurations of magnetic clouds and prominence remnants can satisfactorily be described by the flux rope approximation. It is shown that the magnetic helicities in both parts of the CMEs have the same sign. This sign is consistent with the dominance of CMEs with negative helicity in the northern hemisphere and positive in the southern hemisphere. The results are discussed in the context of different models of CME eruption at the Sun. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Helio Res, La Crescenta, CA 91214 USA. Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM aruzmaik@pop.jpl.nasa.gov; saraf03@delleproduct.com; huqiang@bartol.udel.edu NR 40 TC 19 Z9 19 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9380 EI 2169-9402 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD FEB 28 PY 2003 VL 108 IS A2 AR 1096 DI 10.1029/2002JA009588 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 664TN UT WOS:000182077300002 ER PT J AU Sibeck, DG Trivedi, NB Zesta, E Decker, RB Singer, HJ Szabo, A Tachihara, H Watermann, J AF Sibeck, DG Trivedi, NB Zesta, E Decker, RB Singer, HJ Szabo, A Tachihara, H Watermann, J TI Pressure-pulse interaction with the magnetosphere and ionosphere SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE traveling convection vortices; pressure pulses ID WIND DYNAMIC PRESSURE; TRAVELING CONVECTION VORTICES; MAGNETIC-FIELD SIGNATURES; SOLAR-WIND; BOW SHOCK; EQUATORIAL ELECTROJET; GEOSYNCHRONOUS ORBIT; IMPULSE EVENTS; HIGH-LATITUDES; TWIN VORTICES AB [1] We reexamine traveling convection vortices ( TCVs) seen by the Magnetometer Array for Cusp and Cleft Studies on 9 November 1993. IMP- 8 energetic ion observations confirm that the solar wind pressure variations previously associated with these TCVs were generated by kinetic processes within the Earth's foreshock. As expected during this interval of spiral IMF orientation, fast mode waves launched by the pressure variations first arrived in the equatorial ionosphere near dusk and propagated dawnward. We derive a model for the field- aligned currents generated by transient compressions of the magnetopause and show that it accounts for the number of TCVs seen in the prenoon ionosphere, their sense of rotation, the latitude at which they occur, and their absence in the postnoon ionosphere. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Lab Ciencias Espaciais Santa Maria, BR-97105900 Santa Maria, RS, Brazil. Univ Calif Los Angeles, Los Angeles, CA 90095 USA. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. NOAA, Space Environm Ctr, Boulder, CO 80305 USA. Kyushu Univ, Fukuoka 8120053, Japan. Danish Meteorol Inst, DK-2100 Copenhagen, Denmark. RP Sibeck, DG (reprint author), NASA, Goddard Space Flight Ctr, Code 696,8800 Greenbelt Rd, Greenbelt, MD 20771 USA. RI Sibeck, David/D-4424-2012 NR 45 TC 28 Z9 28 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-SPACE JI J. Geophys. Res-Space Phys. PD FEB 28 PY 2003 VL 108 IS A2 AR 1095 DI 10.1029/2002JA009675 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 664TN UT WOS:000182077300003 ER PT J AU Timofeeva, TV Nesterov, VN Clark, RD Penn, B Frazier, D Antipin, MY AF Timofeeva, TV Nesterov, VN Clark, RD Penn, B Frazier, D Antipin, MY TI Systematic study of polymorphism in crystalline non-linear optical materials SO JOURNAL OF MOLECULAR STRUCTURE LA English DT Article; Proceedings Paper CT 11th International Symposium on Organic Crystal Chemistry CY AUG 20-24, 2001 CL RYDZYNA, POLAND DE polymorphism; X-ray analysis; non-linear optical compounds; organic polytypes ID LANGMUIR-BLODGETT-FILMS; 2ND-HARMONIC GENERATION; 2-CYCLOOCTYLAMINO-5-NITROPYRIDINE; DICYANOVINYLBENZENE; DERIVATIVES; TARTRATE; GROWTH AB Crystalline polymorphism is quite common for non-linear optical (NLO) compounds. During our studies of NLO materials we found several compounds that crystallize in two or more forms. We present a short review of our recent data on the crystalline polymorphisim of NLO compounds. Among the compounds studied, we found examples of concomitant polymorphism, induced conformational polymorphism, and organic polytypism. For several compounds, X-ray data bare discussed along with computational data on molecular and crystal structure energy. (C) 2003 Elsevier Science B.V. All rights reserved. C1 New Mexico Highlands Univ, Dept Chem, Las Vegas, NM 87701 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Russian Acad Sci, Inst Organoelement Cpds, Moscow, Russia. RP Timofeeva, TV (reprint author), New Mexico Highlands Univ, Dept Phys Sci, Box 9000, Las Vegas, NM 87701 USA. EM t_timofeeva@yahoo.com NR 44 TC 20 Z9 20 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-2860 EI 1872-8014 J9 J MOL STRUCT JI J. Mol. Struct. PD FEB 28 PY 2003 VL 647 IS 1-3 BP 181 EP 202 AR PII S0022-2860(02)00523-9 DI 10.1016/S0022-2860(02)00523-9 PG 22 WC Chemistry, Physical SC Chemistry GA 649TW UT WOS:000181224900017 ER PT J AU Chui, T Holmes, W Penanen, K AF Chui, T Holmes, W Penanen, K TI Fluctuations of the phase difference across an array of Josephson junctions in superfluid He-4 SO PHYSICAL REVIEW LETTERS LA English DT Article AB We present a formal thermodynamic treatment of superfluid flow in a Josephson junction. We show that the current i(s) and the phase difference phi are thermodynamic conjugate variables. We derive quantitative expressions for the rms fluctuations of i(s) and phi. Also, we discuss the thermodynamic stability and the thermal activation to the phase-slip region. We apply the developed formalism to show why an array of apertures in He-4 can exhibit the Josephson effect near the lambda transition despite strong thermal fluctuations. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Chui, T (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NR 16 TC 9 Z9 9 U1 0 U2 0 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 FEB 28 PY 2003 VL 90 IS 8 AR 085301 DI 10.1103/PhysRevLett.90.085301 PG 4 WC Physics, Multidisciplinary SC Physics GA 650XL UT WOS:000181289300022 PM 12633434 ER PT J AU Danilin, MY Popp, PJ Herman, RL Ko, MKW Ross, MN Kolb, CE Fahey, DW Avallone, LM Toohey, DW Ridley, BA Schmid, O Wilson, JC Baumgardner, DG Friedl, RR Thompson, TL Reeves, JM AF Danilin, MY Popp, PJ Herman, RL Ko, MKW Ross, MN Kolb, CE Fahey, DW Avallone, LM Toohey, DW Ridley, BA Schmid, O Wilson, JC Baumgardner, DG Friedl, RR Thompson, TL Reeves, JM TI Quantifying uptake of HNO3 and H2O by alumina particles in Athena-2 rocket plume SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE alumina particles; uptake of HNO3 and H2O; rocket emissions ID STRATOSPHERIC OZONE; OXIDE; HCL; COEFFICIENTS; TROPOSPHERE; TEMPERATURE; EMISSIONS; CLONO2; IMPACT; WATER AB [1] The goal of this study is to quantify uptake of H2O and HNO3 by and estimate their residence time on alumina particles in Athena-2 rocket plumes. This study uses in situ measurements made in the lower stratosphere with the NASA WB-57F high-altitude aircraft on 24 September 1999. Constraining the Atmospheric and Environmental Research, Inc. (AER), plume model with available measurements, we found that (1) H2O uptake coefficient for alumina particles is larger than 3 x 10(-4), (2) HNO3 is produced via ClONO2 + HCl --> Cl-2 + HNO3 on alumina particles and resides on their surfaces for 5-52 min, and (3) alumina particles in the plume are covered by 100-200 monolayers of adsorbed H2O and 0.1 - 10 monolayers of HNO3 under lower stratospheric conditions. These values are uncertain by at least a factor of 2. We speculate that the H2O coverage remaining on alumina particles accelerates the ClONO2 + HCl --> Cl-2 + HNO3 reaction, thus leading to a larger than previously thought global ozone loss to solid-fueled rocket emissions, especially if at least several percent of emitted alumina mass are in submicron particles. C1 Boeing Co, MC OR RC, Seattle, WA 98124 USA. NOAA, Aeron Lab, Boulder, CO 80303 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. NASA, Jet Prop Lab, Pasadena, CA 91109 USA. Atmospher & Environm Res Inc, Lexington, MA USA. Aerosp Corp, Los Angeles, CA 90009 USA. Aerodyne Res Inc, Billerica, MA 01821 USA. Univ Colorado, Program Atmospher & Ocean Sci, Boulder, CO 80309 USA. Natl Ctr Atmospher Res, Boulder, CO 80303 USA. Univ Denver, Dept Engn, Denver, CO 80208 USA. Univ Nacl Autonoma Mexico, Ctr Atmospher Sci, Mexico City 04510, DF, Mexico. RP Danilin, MY (reprint author), Boeing Co, MC OR RC, POB 3707, Seattle, WA 98124 USA. EM danilin@h2o.ca.boeing.com RI Kolb, Charles/A-8596-2009; Toohey, Darin/A-4267-2008; Herman, Robert/H-9389-2012; Ko, Malcolm/D-5898-2015; Fahey, David/G-4499-2013; Schmid, Otmar/F-1078-2013 OI Toohey, Darin/0000-0003-2853-1068; Herman, Robert/0000-0001-7063-6424; Fahey, David/0000-0003-1720-0634; NR 25 TC 6 Z9 6 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD FEB 27 PY 2003 VL 108 IS D4 AR 4141 DI 10.1029/2002JD002601 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 664PF UT WOS:000182068900005 ER PT J AU Song, CH Chen, G Hanna, SR Crawford, J Davis, DD AF Song, CH Chen, G Hanna, SR Crawford, J Davis, DD TI Dispersion and chemical evolution of ship plumes in the marine boundary layer: Investigation of O-3/NOy/HOx chemistry SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE ship plume; chemistry; plume evolution; instantaneous NOx lifetime; plume dispersion; Lagrangian plume model ID POWER-PLANT PLUMES; MODEL; EMISSIONS; OZONE; SULFUR; PACIFIC; NITROGEN; CLIMATE; CLOUDS; URBAN AB [1] The dispersion and chemical evolution of NOx in ship plumes has been investigated for marine boundary layer (MBL) conditions. This effort has involved combining a plume dispersion algorithm with a time-dependent photochemical box model. The analysis has considered several factors, all of which can influence the net impact of NOx on the background environment. These include the following: season of the year, latitude of point of release, meteorological setting, and ship NOx emission rate. Reaction rates within a plume were shown to be a nonlinear function of the levels of NOx, leading to relative estimates of ship plume NOx lifetimes that were factors of 2.5-10 times shorter than for ambient marine conditions. The shortened ship-plume NOx lifetime reflects both elevated daytime levels of OH and nighttime levels of NO3 and N2O5, all of which were estimated to be several times larger than those typical of ambient marine conditions. During daylight hours, elevated ship plume OH resulted in the net photochemical production of O-3, with peak concentrations being 5-65% higher than background values, depending on latitude. The areal integrated O-3 effect, however, is estimated to be quite small due to further plume dilution. In addition, because of the shorter estimated lifetime for NOx, it would seem reasonable that the integrated O3 production from the current Lagrangian modeling effort would be significantly lower than that predicted by global 3-D grid models. The current predicted shortened lifetime for NOx is quite significant in terms of assessing a ship plume's impact on background marine levels of NOx. In fact, these results would seem to explain a significant fraction of the overprediction of NOx levels in and near shipping lanes recently estimated using 3-D Eulerian global models. C1 Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. Hanna Consultants, Kennebunkport, ME 04046 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Song, CH (reprint author), Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. EM cs222@prism.gatech.edu RI Crawford, James/L-6632-2013 OI Crawford, James/0000-0002-6982-0934 NR 41 TC 37 Z9 37 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD FEB 27 PY 2003 VL 108 IS D4 AR 4143 DI 10.1029/2002JD002216 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 664PF UT WOS:000182068900002 ER PT J AU Liu, JP Schmidt, GA Martinson, DG Rind, D Russell, G Yuan, XJ AF Liu, JP Schmidt, GA Martinson, DG Rind, D Russell, G Yuan, XJ TI Sensitivity of sea ice to physical parameterizations in the GISS global climate model SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article DE sea ice sensitivity to physical parameterizations ID OCEAN CIRCULATION MODELS; MESOSCALE TRACER TRANSPORTS; ARCTIC-OCEAN; FRESH-WATER; THICKNESS; SIMULATIONS; VARIABILITY; DYNAMICS; LAYER; CO2 AB [1] The GISS coupled model is used to investigate the sensitivity of sea ice to each of the following parameterizations: (1) two sea ice dynamics (CF: cavitating fluid; VP: viscous-plastic), (2) the specification of oceanic isopycnal mixing coefficients in the Gent and McWillams isopyncal mixing (GM), and (3) the wajsowicz viscosity diffusion (WV). The large-scale sea ice properties are highly sensitive to sea ice dynamics. With the inclusion of resistance to shear stress, VP captures the major observed sea ice drift features and improves the simulations of sea ice concentrations, thickness, and export through Fram Strait relative to CF. GM significantly improves the simulation of vertical temperature distributions in the Southern Ocean, although it leads to a dramatic reduction of Antarctic sea ice cover. The reduced oceanic isopycnal mixing coefficients lead to Arctic sea ice that tends to be less and thinner in almost the entire Arctic except in the North Pacific and Labrador Sea, while Antarctic sea ice that extends more equatorward throughout the circumpolar regions. The responses of sea ice to WV show an enlargement and thickening of sea ice in the Arctic, within the ice packs around the Antarctic and a reduction and thinning of sea ice in the northernWeddell and Ross Seas. On the basis of these experiments, two composite experiments with the best parameterizations are investigated. The atmospheric responses associated with sea ice changes are discussed. While improvements are seen, there are still many unrealistic aspects that will require further improvements to sea ice and ocean components. C1 NASA, Goddard Space Flight Ctr, Inst Space Studies, New York, NY 10025 USA. Columbia Univ, Lamont Doherty Earth Observ, Palisades, NY 10964 USA. Columbia Univ, Dept Earth & Environm Sci, Palisades, NY USA. Columbia Univ, Ctr Climate Syst Res, New York, NY USA. RP Liu, JP (reprint author), NASA, Goddard Space Flight Ctr, Inst Space Studies, New York, NY 10025 USA. RI Schmidt, Gavin/D-4427-2012; LIU, JIPING/N-6696-2016 OI Schmidt, Gavin/0000-0002-2258-0486; NR 60 TC 23 Z9 25 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 FEB 27 PY 2003 VL 108 IS C2 AR 3053 DI 10.1029/2001JC001167 PG 17 WC Oceanography SC Oceanography GA 664QU UT WOS:000182072400002 ER PT J AU Wilson, EH Atreya, SK Coustenis, A AF Wilson, EH Atreya, SK Coustenis, A TI Mechanisms for the formation of benzene in the atmosphere of Titan SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article DE Titan; benzene formation; PAH; ISO observations; aromatic chemistry; propargyl ID POLYCYCLIC AROMATIC-HYDROCARBONS; METASTABLE DIACETYLENE; RATE COEFFICIENTS; ISO OBSERVATIONS; CHEMISTRY; JUPITER; FLAMES; RECOMBINATION; ACETYLENE; PHOTODISSOCIATION AB [1] Polycyclic aromatic hydrocarbons (PAHs) are important interstellar species, and their precursor benzene (C6H6) has been detected in our solar system. In this study the possibility of benzene formation in the atmosphere of Titan is investigated. Benzene abundance in Titan's atmosphere is found to be rather highly dependent on the assumed mechanism for benzene production. Assuming reactions involved in this mechanism to proceed at the rate corresponding to 300 K, a value of 5.4 x 10(-7) at 2 x 10(-5) mbar is found for the mole fraction of benzene. The primary mechanism responsible for this benzene abundance involves the recombination of propargyl (C3H3) radicals. A source of benzene molecules through ion chemistry in the upper atmosphere is also investigated. The inclusion of heavy cyclic ions results in little change in the C6H6 abundance at the peak in mole fraction, where [C6H6] = 3.6 x 10(5) cm(-3), but does produce about a factor of 2 increase in the benzene mole fraction at the 10(-6) mbar level [C6H6] = 1 x 10(4) cm(-3). This produces a negligible change in C6H6 column abundance below this microbar level. In the stratosphere, Infrared Space Observatory (ISO) measurements of the benzene abundance have been fit by our nominal profile multiplied by a factor of 3.0 +/- 0.5. Taking the lower value of this factor, the ISO fit corresponds to an altitude-dependent benzene profile with a value of 9.8 x 10(-11) at 1 mbar. Benzene profiles determined in this study suggest an important path for the formation of higher-order hydrocarbons, which may play a significant role in the formation of hazes in Titan's atmosphere. C1 Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48109 USA. Observ Paris, LESIA, F-92195 Meudon, France. RP Wilson, EH (reprint author), NASA, Jet Propuls Lab, 4800 Oak Grove Dr,M-S 169-237, Pasadena, CA 91109 USA. NR 44 TC 66 Z9 67 U1 1 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD FEB 26 PY 2003 VL 108 IS E2 AR 5014 DI 10.1029/2002JE001896 PG 10 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 664RW UT WOS:000182075600001 ER PT J AU Robertson, FR Fitzjarrald, DE Kummerow, CD AF Robertson, FR Fitzjarrald, DE Kummerow, CD TI Effects of uncertainty in TRMM precipitation radar path integrated attenuation on interannual variations of tropical oceanic rainfall SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID EL-NINO; PATTERNS; INDEXES; ENSO AB [1] Considerable uncertainty surrounds the issue of whether precipitation over the tropical oceans (30degrees N/S) systematically changes with interannual sea-surface temperature (SST) anomalies that accompany El Nino (warm) and La Nina (cold) events. Time series of rainfall estimates from the Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR) over the tropical oceans show marked differences with estimates from two TRMM Microwave Imager (TMI) passive microwave algorithms. We show that path-integrated attenuation derived from the effects of precipitation on the radar return from the ocean surface exhibits interannual variability that agrees closely with the TMI time series. Our analysis of discrepancies between the PR rainfall and attenuation suggests that uncertainty in the assumed drop size distribution and associated attenuation/reflectivity/rainfall relationships inherent in single-frequency radar methods is a serious issue for studies of interannual variability. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35805 USA. Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. RP Robertson, FR (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35805 USA. NR 15 TC 28 Z9 28 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 FEB 25 PY 2003 VL 30 IS 4 AR 1180 DI 10.1029/2002GL016416 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 664NC UT WOS:000182066300005 ER PT J AU Qi, DW Luo, LS AF Qi, DW Luo, LS TI Rotational and orientational behaviour of three-dimensional spheroidal particles in Couette flows SO JOURNAL OF FLUID MECHANICS LA English DT Article ID LATTICE BOLTZMANN METHOD; REYNOLDS-NUMBER FLOWS; PARTICULATE SUSPENSIONS; NUMERICAL SIMULATIONS; 3-DIMENSIONAL SPACE; NONIDEAL GASES; EQUATION; INERTIA; MODELS; FLUID AB This paper reports the results of lattice Boltzmann simulations of the rotation behaviour of neutrally buoyant spheroidal particles in a three-dimensional Couette flow. We find several distinctive states depending on the Reynolds number range and particle shape. As the Reynolds number increases, rotation may change from one state to another. For a prolate spheroid, two rotation transitions are found. In the low Reynolds number range 0 < R < R-1 approximate to 205, the prolate spheroid rotates around its minor axis, which is parallel to the vorticity vector of the flow. The rate of rotation is a periodic function of time. In the intermediate Reynolds number range R-1 < R < R-2 approximate to 345, the prolate spheroid precesses about the vorticity direction with a nutational motion. The angular velocities are periodic functions of time. The mean nutation angle between the major axis and the vorticity increases monotonically as the Reynolds number increases. In the high Reynolds number range R-2 < R < 467, the prolate spheroid rotates with a constant rate around its major axis, which is parallel to the vorticity. For an oblate spheroid, only one rotation transition is observed. In the lower Reynolds number range 0 < R < R-1' approximate to 220, the oblate spheroid finally spins with a constant rate around its minor axis (the symmetric axis of the revolution), which is parallel to the vorticity vector. In the higher Reynolds number range 220 approximate to R-1' < R < 467, the oblate spheroid still spins with a constant rate around its minor axis but there is a finite inclination angle between the minor axis and the vorticity vector. This angle increases as the Reynolds number increases. C1 Western Michigan Univ, Coll Engn & Appl Sci, Dept Paper & Printing Sci & Engn, Kalamazoo, MI 49008 USA. NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. RP Qi, DW (reprint author), Western Michigan Univ, Coll Engn & Appl Sci, Dept Paper & Printing Sci & Engn, Kalamazoo, MI 49008 USA. RI Luo, Li-Shi/A-4561-2011 OI Luo, Li-Shi/0000-0003-1215-7892 NR 34 TC 49 Z9 51 U1 0 U2 9 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 FEB 25 PY 2003 VL 477 BP 201 EP 213 DI 10.1017/S0022112002003191 PG 13 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 670NL UT WOS:000182414800007 ER PT J AU Langlais, B Mandea, M Ultre-Guerard, P AF Langlais, B Mandea, M Ultre-Guerard, P TI High-resolution magnetic field modeling: application to MAGSAT and Orsted data SO PHYSICS OF THE EARTH AND PLANETARY INTERIORS LA English DT Article; Proceedings Paper CT 1st Joint Meeting of the IAGA/IASPEI CY 2001 CL HANOI, VIETNAM SP IAGA, IASPEI DE magnetic field; satellite data; modeling ID MAIN GEOMAGNETIC-FIELD; SECULAR VARIATION; SATELLITE; CORE; OBSERVATORIES; GENERATION; BOUNDARY AB Launched on 23rd February 1999, the Orsted satellite opened the decade of geopotential field research. This is the first satellite to measure the three components of the Earth's magnetic field since MAGSAT (1979-1980). Orsted orbital parameters are very similar to those of MAGSAT, allowing a first-order comparison of the 1979 and 2000 magnetic fields. Using the available vector and scalar data over the first 14 months of the Orsted mission and applying classical selection criteria (local time, external magnetic activity), we compute a 29-degree/order main-field model and a 13-degree/order secular-variation model for the period 1999-2000. The applied method and the accuracy of the derived model are discussed. We compare the resulting main-field model to a similar one derived from MAGSAT data. Results of this comparison are presented, such as (i) morphology and energy spectrum of the secular variation and (ii) morphology of the crustal magnetic field at MAGSAT and Orsted epochs. (C) 2003 Elsevier Science B.V. All rights reserved. C1 Inst Phys Globe, F-75252 Paris 5, France. NASA, Goddard Space Flight Ctr, NAS, NRC, Greenbelt, MD 20771 USA. Ctr Natl Etud Spatiales, F-75039 Paris 1, France. RP Langlais, B (reprint author), Inst Phys Globe, BP 89,4 Pl Jussieu, F-75252 Paris 5, France. EM langlais@geomag.gsfc.nasa.gov RI MANDEA, Mioara/E-4892-2012; Langlais, Benoit/K-5366-2012 OI Langlais, Benoit/0000-0001-5207-304X NR 28 TC 22 Z9 28 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0031-9201 J9 PHYS EARTH PLANET IN JI Phys. Earth Planet. Inter. PD FEB 25 PY 2003 VL 135 IS 2-3 BP 77 EP 91 DI 10.1016/S0031-9201(02)00207-8 PG 15 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 662QM UT WOS:000181959200002 ER PT J AU Namiki, M Kawai, N Kotani, T Makishima, K AF Namiki, M Kawai, N Kotani, T Makishima, K TI Evidence for jet collimation in SS 433 with the Chandra HETGS SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN LA English DT Article DE jets; stars : binaries : general; stars : individual (SS 433); X-rays : individual (SS 433); X-rays : spectra ID X-RAY-SPECTRUM; SS433; LINE; EMISSION AB High-resolution X-ray spectra of SS 433 obtained after a binary egress with the Chandra High Energy Transmission Grating Spectrometer (HETGS) were studied. Many Doppler-shifted X-ray emission lines from highly ionized elements were detected. The initial temperature of the jets is estimated to be 20 keV. The lines are found to generally be broader than the instrumental resolution. The widths of the Fe xxv Kalpha and Si XIII Kalpha lines correspond to velocity dispersions of 2100(-340)(+600) km s(-1) and 840(-150)(+180) km s(-1) respectively, in terms of Gaussian sigma. Neither the measured line widths nor their dependence on the atomic number can be explained by thermal broadening alone. Alternative explanations of the observed line widths are discussed, including in particular a progressive jet collimation along its axis. C1 RIKEN, Inst Phys & Chem Res, Wako, Saitama 3510198, Japan. Tokyo Univ Sci, Dept Phys, Shinjuku Ku, Tokyo 1628601, Japan. Tokyo Inst Technol, Dept Phys, Meguro Ku, Tokyo 1520033, Japan. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Univ Tokyo, Dept Phys, Bunkyo Ku, Tokyo 1130033, Japan. RP RIKEN, Inst Phys & Chem Res, 2-1 Hirosawa, Wako, Saitama 3510198, Japan. EM namiki@crab.riken.go.jp; nkawai@tithp1.hp.phys.titech.ac.jp; kotani@milkyway.gsfc.nasa.gov; maxima@phys.s.u-tokyo.ac.jp NR 17 TC 23 Z9 23 U1 0 U2 0 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0004-6264 EI 2053-051X J9 PUBL ASTRON SOC JPN JI Publ. Astron. Soc. Jpn. PD FEB 25 PY 2003 VL 55 IS 1 BP 281 EP 288 DI 10.1093/pasj/55.1.281 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 653MZ UT WOS:000181441500022 ER PT J AU Eck, TF Holben, BN Ward, DE Mukelabai, MM Dubovik, O Smirnov, A Schafer, JS Hsu, NC Piketh, SJ Queface, A Le Roux, J Swap, RJ Slutsker, I AF Eck, TF Holben, BN Ward, DE Mukelabai, MM Dubovik, O Smirnov, A Schafer, JS Hsu, NC Piketh, SJ Queface, A Le Roux, J Swap, RJ Slutsker, I TI Variability of biomass burning aerosol optical characteristics in southern Africa during the SAFARI 2000 dry season campaign and a comparison of single scattering albedo estimates from radiometric measurements SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE atmospheric aerosols; biomass burning; Africa; optical characteristics ID SKY RADIANCE MEASUREMENTS; BLACK CARBON; WAVELENGTH DEPENDENCE; BRAZILIAN AMAZON; SMOKE PARTICLES; FIELD CAMPAIGN; SCAR-B; DEPTH; IRRADIANCE; RADIATION AB [1] Measurements of the column-integrated aerosol optical properties in the southern African region were made by Aerosol Robotic Network (AERONET) Sun-sky radiometers at several sites in August-September 2000 as a part of the Southern African Regional Science Initiative (SAFARI) 2000 dry season field campaign. Fine mode biomass burning aerosols dominated in the northern part of the study region (Zambia), which is an active burning region, and other aerosols including fossil fuel burning, industrial, and aeolian coarse mode types also contributed to the aerosol mixture in other regions (South Africa and Mozambique), which were not as strongly dominated by local burning. The large amount of smoke produced in the north lead to a north-south gradient in aerosol optical depth (tau(a)) in September, with biomass burning aerosol concentrations reduced by dispersion and deposition during transport. Large average diurnal variations of ta (typical diurnal range of 25%) were observed at all sites in Zambia as a result of large diurnal trends in fire counts in that region that peak in midafternoon. However, for all sites located downwind to the south, there was relatively little (similar to5-10%) average diurnal trend observed as the aerosol transport is not strongly influenced by diurnal cycles. AERONET radiometer retrievals of aerosol single scattering albedo (omega(0)) in Zambia showed relatively constant values as a function of tau(a) for tau(a440) ranging from 0.4 to similar to2.5. The wavelength dependence of omega(0) varied significantly over the region, with greater decreases for increasing wavelength at smoke-dominated sites than for sites influenced by a significant coarse mode aerosol component. Retrievals of midvisible omega(0) based on the fitting of Photosynthetically Active Radiation (PAR; 400-700 nm) flux measurements to modeled fluxes for smoke in Mongu, Zambia yielded an average value of 0.84. This is in close agreement with the estimated average of 0.85 derived from interpolation of the AERONET retrievals made at 440 and 675 nm for August-September 2000. The spectral dependence of omega(0) independently retrieved with the AERONET measurements and with diffuse fraction measurements in Mongu, Zambia was similar for both techniques, as a result of both methods retrieving the imaginary index of refraction (similar to0.030-0.035 on one day) with very little wavelength dependence. C1 Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. NASA, Biospher Sci Branch, Goddard Space Flight Ctr, Greenbelt, MD USA. Etosha Ecol Inst, Okaukuejo, Namibia. Zambian Meteorol Dept, Mongu, Zambia. Univ Witwatersrand, Climatol Res Grp, Gauteng, South Africa. Univ Virginia, Dept Environm Sci, Charlottesville, VA 22903 USA. Enviropyron, White Salmon, WA USA. RP Eck, TF (reprint author), Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. EM tom@aeronet.gsfc.nasa.gov RI Dubovik, Oleg/A-8235-2009; Schafer, Joel/A-3978-2010; Smirnov, Alexander/C-2121-2009; ECK, THOMAS/D-7407-2012; Hsu, N. Christina/H-3420-2013 OI Dubovik, Oleg/0000-0003-3482-6460; Smirnov, Alexander/0000-0002-8208-1304; NR 50 TC 151 Z9 152 U1 2 U2 20 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 FEB 22 PY 2003 VL 108 IS D13 AR 8477 DI 10.1029/2002JD002321 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 663BF UT WOS:000181984600001 ER PT J AU Scranton, R AF Scranton, R TI Testing the halo model against the SDSS photometric survey SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE methods : numerical; large-scale structure of Universe ID DIGITAL SKY SURVEY; GALAXY FORMATION; POWER SPECTRUM; ANALYTIC MODEL; DARK; EVOLUTION; PROFILES; CONDENSATION; UNIVERSE; BIAS AB We present halo model predictions for the expected angular clustering and associated errors from the completed Sloan Digital Sky Survey (SDSS) photometric galaxy sample. These results are used to constrain halo model parameters under the assumption of a fixed LambdaCDM cosmology using standard Fisher matrix techniques. Given the ability of the five-colour SDSS photometry to separate galaxies into subpopulations by intrinsic colour, we also use extensions of the standard halo model formalism to calculate the expected clustering of red and blue galaxy subpopulations as a further test of the galaxy evolution included in the semi-analytical methods for populating dark matter haloes with galaxies. The extremely small sample variance and Poisson errors from the completed SDSS should result in very impressive constraints (similar to1-10 per cent) on the halo model parameters for a simple magnitude-limited sample and should provide an extremely useful check on the behaviour of current and future N -body simulations and semi-analytical techniques. We also show that similar constraints are possible using a narrow selection function, as would be possible using photometric redshifts, without making linear assumptions regarding the evolution of the underlying power spectra. In both cases, we explore the effects of uncertainty in the selection function on the resulting constraints and the degeneracies between various combinations of parameters. C1 Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. NASA, Fermilab Astrophys Ctr, Batavia, IL 60510 USA. RP Scranton, R (reprint author), Univ Chicago, Dept Astron & Astrophys, 5640 S Ellis Ave, Chicago, IL 60637 USA. NR 37 TC 20 Z9 20 U1 0 U2 0 PU BLACKWELL PUBLISHING LTD PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DG, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD FEB 21 PY 2003 VL 339 IS 2 BP 410 EP 426 DI 10.1046/j.1365-8711.2003.06174.x PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 645HT UT WOS:000180970700011 ER PT J AU Laycock, S Corbet, RHD Coe, MJ Marshall, FE Markwardt, C Edge, W AF Laycock, S Corbet, RHD Coe, MJ Marshall, FE Markwardt, C Edge, W TI X-ray and optical observations of XTE J0052-723: A transient Be/X-ray pulsar in the Small Magellanic Cloud SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE stars : general; pulsars : general; pulsars : individual : XTE J0052-723; Magellanic Clouds; X-rays : binaries ID SPECTRAL-ANALYSIS; SMC; BINARIES; STARS AB On 2000 December 27, during our regular Small Magellanic Cloud (SMC) monitoring programme using the Rossi X-ray Timing Explorer (RXTE ), strong pulsations were detected with a period of 4.78 s. Subsequent slew observations performed on January 9 and 13 across the field of view allowed localization of the pulsar's position to RA: 0(h) 52(m) 17(s) , Dec.: 72degrees19'51' (J2000). The outburst continued until January 24; seven PCA observations were obtained during this period, yielding a maximum X-ray luminosity similar to10(38) erg s(-1). Following calculation of the pulsar position, optical observations of the RXTE error box were made on 2001 January 16 with the 1-m telescope of the South African Astronomical Observatory (SAAO) while the source was still in X-ray outburst. Candidate Be stars identified from their photometric colours were subsequently observed with the SAAO 1.9-m telescope on 2001 November 7 to obtain spectra. Only one of the photometrically identified stars [MA93]537 showed prominent Halpha emission, with a double peaked line-profile (EW =-43.3 +/- 0.7 Angstrom, separation v = 200 +/- 15 km s(-1)), confirming the presence of a substantial circumstellar disc. C1 Univ Southampton, Dept Phys & Astron, Southampton SO17 1BJ, Hants, England. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Space Res Assoc, Columbia, MD 21044 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. RP Laycock, S (reprint author), Univ Southampton, Dept Phys & Astron, Southampton SO17 1BJ, Hants, England. NR 35 TC 10 Z9 10 U1 0 U2 0 PU BLACKWELL PUBLISHING LTD PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DG, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD FEB 21 PY 2003 VL 339 IS 2 BP 435 EP 441 DI 10.1046/j.1365-8711.2003.06179.x PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 645HT UT WOS:000180970700013 ER PT J AU Clarkson, WI Charles, PA Coe, MJ Laycock, S Tout, MD Wilson, CA AF Clarkson, WI Charles, PA Coe, MJ Laycock, S Tout, MD Wilson, CA TI Long-term properties of accretion discs in X-ray binaries - I. The variable third period in SMC X-1 SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE accretion, accretion discs; binaries : close; stars : individual : SMC X-1; pulsars : general; X-rays : stars ID TIME-SERIES ANALYSIS; UNEVENLY SPACED DATA; NEUTRON-STAR; SPECTROSCOPY; HERCULES-X-1; VARIABILITY; OCCULTATION; PULSARS; BATSE AB Long-term X-ray monitoring data from the Rossi X-Ray Timing Explorer (RXTE ) All-Sky Monitor (ASM) and the Compton Gamma Ray Observatory (CGRO ) Burst And Transient Source Experiment (BATSE) reveal that the third (superorbital) period in SMC X-1 is not constant, but varies between 40 and 60 d. A dynamic power spectrum analysis indicates that the third period has been present continuously throughout the five years of ASM observations. This period changed smoothly from 60 to 45 d and then returned to its former value, on a time-scale of approximately 1600 d. During the nearly 4 yr of overlap between the CGRO and RXTE missions, the simultaneous BATSE hard X-ray data confirm and extend this variation in SMC X-1. Our discovery of such an instability in the superorbital period of SMC X-1 is interpreted in the context of recent theoretical studies of warped, precessing accretion discs. We find that the behaviour of SMC X-1 is consistent with a radiation-driven warping model. C1 Univ Southampton, Dept Phys & Astron, Southampton SO17 1BJ, Hants, England. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35805 USA. RP Clarkson, WI (reprint author), Univ Southampton, Dept Phys & Astron, Southampton SO17 1BJ, Hants, England. NR 40 TC 45 Z9 45 U1 0 U2 0 PU BLACKWELL PUBLISHING LTD PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DG, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD FEB 21 PY 2003 VL 339 IS 2 BP 447 EP 454 DI 10.1046/j.1365-8711.2003.06176.x PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 645HT UT WOS:000180970700015 ER PT J AU Jarzembski, MA Norman, ML Fuller, KA Srivastava, V Cutten, DR AF Jarzembski, MA Norman, ML Fuller, KA Srivastava, V Cutten, DR TI Complex refractive index of ammonium nitrate in the 2-20-mu m spectral range SO APPLIED OPTICS LA English DT Article ID SAN-JOAQUIN VALLEY; OPTICAL-CONSTANTS; AEROSOL; DUST; SULFATE; BACKSCATTER; WAVELENGTHS; EXTINCTION; WATER; ACID AB Using high-resolution Fourier-transform infrared absorbance and transmittance spectral data for ammonium sulfate (AMS), calcium carbonate (CAC), and ammonium nitrate (AMN), we made comparisons with previously published complex refractive-index data for AMS and CAC to infer experimental parameters to determine the imaginary refractive index for AMN in the infrared wavelength range from 2 to 20 mum. Subtractive K-ramers-Kronig mathematical relations were applied to calculate the real refractive index for the three compositions. Excellent agreement for AMS and CAC with the published values was found, validating the complex refractive index obtained for AMN. We performed backscatter calculations using a log-normal size distribution for AMS, AMN, and CAC aerosols to show differences in their backscattered. spectra. (C) 2003 Optical Society of America. C1 Global Hydrol & Climate Ctr, Huntsville, AL 35805 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Alabama, Huntsville, AL 35899 USA. Univ Space Res Assoc, Columbia, MD USA. Univ N Carolina, Chapel Hill, NC 27515 USA. RP Jarzembski, MA (reprint author), Global Hydrol & Climate Ctr, 320 Sparkman Dr, Huntsville, AL 35805 USA. EM maurice.jarzembski@msfc.nasa.gov NR 27 TC 18 Z9 18 U1 3 U2 9 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 FEB 20 PY 2003 VL 42 IS 6 BP 922 EP 930 DI 10.1364/AO.42.000922 PG 9 WC Optics SC Optics GA 648GJ UT WOS:000181141700005 PM 12617206 ER PT J AU Jones, BK Saylor, JR Bliven, LF AF Jones, BK Saylor, JR Bliven, LF TI Single-camera method to determine the optical axis position of ellipsoidal drops SO APPLIED OPTICS LA English DT Article ID LABORATORY MEASUREMENTS; RAINDROP OSCILLATIONS; FIELD; SCATTERING; RATIOS; MODEL; SHAPE AB The sizing of droplets by optical imaging typically requires a small depth of field so that variations in the magnification ratio are minimized. However, if the location of the drop along the optical axis can be determined, a variable magnification ratio can be imposed on each imaged drop, and the depth of field can be increased. Previous research suggested that droplet location can be determined with a characteristic of droplet images that is obtained when the droplet is illuminated from behind. In this prior research, the method was demonstrated with spherical glass objects to simulate raindrops. Raindrops are known to deviate significantly from a spherical shape, especially when the drop size is large. We demonstrate the ability to locate the position of objects that deviate from sphericity. Deformed water drops and glass ellipsoids are tested, along with glass spheres. The role of refractive index is also discussed. (C) 2003 Optical Society of America. C1 Clemson Univ, Dept Mech Engn, Clemson, SC 29634 USA. NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Wallops Isl, VA 23337 USA. RP Jones, BK (reprint author), Clemson Univ, Dept Mech Engn, Clemson, SC 29634 USA. EM jrsaylor@ces.clemson.edu RI bliven, francis/E-1450-2012 NR 21 TC 10 Z9 10 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 FEB 20 PY 2003 VL 42 IS 6 BP 972 EP 978 DI 10.1364/AO.42.000972 PG 7 WC Optics SC Optics GA 648GJ UT WOS:000181141700010 PM 12617211 ER PT J AU Sarkissian, E Bowman, KW AF Sarkissian, E Bowman, KW TI Application of a nonuniform spectral resampling transform in Fourier-transform spectrometry SO APPLIED OPTICS LA English DT Article AB We describe a nonuniform spectral resampling transform (NUSRT) that resamples a frequency-scaled spectrum that has been measured by a Fourier-transform spectrometer (FTS). Frequency scaling of a spectrum can arise from measurements made with off-axis detectors and Doppler shifts induced by motion of a spaceborne FTS relative to an input radiation source. In addition, a spectrum may need to be resealed in frequency to match spectral lines for applications such as the retrieval of atmospheric state parameters. The NUSRT is cast as a linear algebraic expression that relates a nonuniformly sampled interferogram to an input spectrum. A polynomial approximation is applied to this expression that reduces the inverse of the NUSRT to a series of Fourier transforms that can be implemented as fast Fourier transforms (FFTs). We show that this NUSRT algorithm requires on the order of 6N log N flops, which reduces the computational cost of resealing by more than 1 order of magnitude compared with conventional FFT-based Shannon interpolation techniques while comparable accuracy is maintained. (C) 2003 Optical Society of America. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Sarkissian, E (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS-183-301, Pasadena, CA 91109 USA. EM edwin.sarkissian@jpl.nasa.gov; kevin.bowman@jpl.nasa.gov NR 18 TC 7 Z9 7 U1 1 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 FEB 20 PY 2003 VL 42 IS 6 BP 1122 EP 1131 DI 10.1364/AO.42.001122 PG 10 WC Optics SC Optics GA 648GJ UT WOS:000181141700030 PM 12617230 ER PT J AU Coble, K Dodelson, S Dragovan, M Ganga, K Knox, L Kovac, J Ratra, B Souradeep, T AF Coble, K Dodelson, S Dragovan, M Ganga, K Knox, L Kovac, J Ratra, B Souradeep, T TI Cosmic microwave background anisotropy measurement from Python V SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic microwave background; cosmology : observations ID ANGULAR POWER SPECTRUM; DARK-MATTER COSMOGONIES; CONSTRAINTS; SKY AB We analyze observations of the microwave sky made with the Python experiment in its fifth year of operation at the Amundsen-Scott South Pole Station in Antarctica. After modeling the noise and constructing a map, we extract the cosmic signal from the data. We simultaneously estimate the angular power spectrum in eight bands ranging from large (1similar to40) to small (lsimilar to260) angular scales, with power detected in the first six bands. There is a significant rise in the power spectrum from large to smaller (lsimilar to200) scales, consistent with that expected from acoustic oscillations in the early universe. We compare this Python V map to a map made from data taken in the third year of Python. Python III observations were made at a frequency of 90 GHz and covered a subset of the region of the sky covered by Python V observations, which were made at 40 GHz. Good agreement is obtained both visually ( with a filtered version of the map) and via a likelihood ratio test. C1 Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. Adler Planetarium & Astron Museum, Chicago, IL 60605 USA. Fermilab Natl Accelerator Lab, Batavia, IL 60510 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Ctr Infrared Proc & Anal, Pasadena, CA 91125 USA. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. Kansas State Univ, Dept Phys, Manhattan, KS 66506 USA. Interuniv Ctr Astron & Astrophys, Pune 411007, Maharashtra, India. RP Coble, K (reprint author), Univ Chicago, Enrico Fermi Inst, 5640 S Ellis Ave, Chicago, IL 60637 USA. RI Ratra, Bharat/I-4979-2012 NR 27 TC 11 Z9 11 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 20 PY 2003 VL 584 IS 2 BP 585 EP 592 DI 10.1086/345714 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 643WG UT WOS:000180884100006 ER PT J AU Parravano, A Hollenbach, DJ McKee, CF AF Parravano, A Hollenbach, DJ McKee, CF TI Time dependence of the ultraviolet radiation field in the local interstellar medium SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : evolution; ISM : structure; stars : formation; stars : luminosity function, mass function ID INITIAL MASS FUNCTION; STANDARD STELLAR LIBRARY; REGULATED STAR FORMATION; B-TYPE STARS; H-I; MOLECULAR CLOUDS; OB ASSOCIATIONS; RUNAWAY STARS; PHOTODISSOCIATION REGIONS; EVOLUTIONARY SYNTHESIS AB Far-ultraviolet (FUV, 6 eV < h nu < 13.6 eV) radiation has been suggested as the main source of heating of the neutral interstellar gas, and, in this case, it determines whether the thermal balance of the neutral gas results in cold (T similar to 50-100 K) clouds ( cold neutral material [CNM]), warm (T similar to 10(4) K) clouds (warm neutral material [WNM]), or a combination of the two. For gas at fixed mean density, high FUV fields convert the neutral gas to WNM, while low fields result in CNM. The main sources of interstellar FUV radiation are short-lived massive stars in associations that form in giant molecular clouds. Using McKee & Williams distribution of birthrates for OB associations in the Galaxy, we determine the expected behavior of the time-dependent FUV field for random positions in the ISM at the solar circle. The FUV field is calculated in two bands (912-1100 and 912-2070 Angstrom) and at the wavelength 1400 Angstrom. In terms of U(-17)= U/ (10(-17) ergs cm(-3) Angstrom(-1)), where U is the energy density of the radiation field in some band, we find ( mean, median) values at the solar circle of U(-17) = (15.7, 7.4) and (14.2, 7.2) for the 912-1100 and 912-2070 Angstrom bands, respectively. At 1400 Angstrom we find (mean, median) values of U(-17) = (14.4; 7.5). Our median value for the 912-2070 Angstrom band is G(0) = 1.6 times Habing's value for the radiation field at the solar circle in this band and quite close to Draine's value, G(0) = 1.7. Habing and Draine's values are based on observations of sources of FUV radiation in the solar neighborhood, so all three values are close to observed values. Because of attenuation by dust, only associations within about 500 pc contribute significantly to the energy density at a given point. Large-angle scattering produces a diffuse field that is about 10% of the field produced by the sum of direct and small-angle ( < 5) scattering from discrete sources ( the associations), as observed. At a point exposed to the median radiation field, the brightest association typically produces about 20% of the total energy density. At a point exposed to an above average radiation field, the brightest association produces most of the energy density. Therefore, the FUV field is asymmetric at a given point, and the asymmetry grows for higher fields. The FUV field fluctuates with a variety of amplitudes, the larger ones being less frequent. The mean field is about twice the median field because of these fluctuations, or spikes, in the radiation field. These spikes, which last similar to 30 Myr, are caused by the infrequent birth of nearby associations. For spikes that are significantly higher than the mean field, the time interval between spikes is similar to 2U(-15)(3/2) Gyr. We also model shorter duration spikes caused by runaway OB stars. The presence of a fluctuating heating rate created by the fluctuating FUV field converts CNM to WNM and vice versa. C1 Univ Los Andes, Ctr Astrofis Teor, Merida 5101A, Venezuela. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. RP Parravano, A (reprint author), Univ Los Andes, Ctr Astrofis Teor, Merida 5101A, Venezuela. NR 64 TC 63 Z9 63 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 20 PY 2003 VL 584 IS 2 BP 797 EP 817 DI 10.1086/345807 PN 1 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 643WG UT WOS:000180884100026 ER PT J AU Ressler, ME Barsony, M AF Ressler, ME Barsony, M TI Structure of the mid-infrared emitting disk around WL 16 SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; dust, extinction; infrared : ISM; stars : formation; stars : individual (WL 16); stars : pre-main-sequence ID YOUNG STELLAR OBJECTS; AROMATIC HYDROCARBON CATIONS; OPHIUCHI DARK CLOUD; HERBIG AE/BE STARS; T-TAURI STARS; EMISSION FEATURES; CO EMISSION; INTERSTELLAR GRAINS; SCORPIO-CENTAURUS; SIZE DISTRIBUTION AB WL 16 is a unique member of the embedded young stellar population in the nearby rho Ophiuchi cloud core: its extended, high surface brightness disk is visible only at mid-infrared wavelengths. We present diffraction-limited images, from 7.9 to 24.5 mum, of WL 16 acquired at the Keck II telescope. We take advantage of the similar to0."3 angular resolution of the mid-infrared images to derive physical parameters for the central object by self-consistently combining them with available near-infrared spectroscopy, point-spread function fit photometry, and pre-main-sequence evolutionary tracks. We find the central star to be a 250 L., 4 M., Herbig Ae star, seen through foreground material of the rho Oph cloud core that provides an extinction of A(V) = 31 +/- 1 mag. WL 16's disk is detected through all nine observed passbands, not only those four that sample polycyclic aromatic hydrocarbon (PAH) emission features. We confirm, therefore, that the emitting particles are composed of both PAHs and very small (5-100 Angstrom) graphitic grains. The disk size as observed through the four PAH filters is 7" x 3."5, corresponding to a disk diameter of similar to900 AU. The disk's major axis is at a position angle of 60degrees +/- 2degrees and is viewed at an inclination angle of 62.degrees2 +/- 0.degrees4 to our line of sight. Our derived inclination angle is in excellent agreement with the inclination previously inferred for the inner disk (R less than or equal to 30 R.) from kinematic modeling of the near-infrared spectral lines of CO. We can distinguish structure within the PAH disk at unprecedented resolution. We confirm a resolved (1."5 diameter) core component at 7.9 and 8.8 mum due to emission from positively charged PAHs. An enhancement in the emission at 12.5 mum at the disk's edges is found for the first time and signals the presence of larger (greater than or equal to50-80 carbon atoms) and/or more hydrogenated PAHs than those found in the bulk of the disk. We find a disk asymmetry, observed at all nine mid-infrared wavelengths, at projected radii 1"-2."5 ( corresponding to 125 AU less than or equal to r less than or equal to 300 AU) from the central source. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Space Sci Inst, Boulder, CO 80303 USA. RP Ressler, ME (reprint author), CALTECH, Jet Prop Lab, MS 169-327,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 58 TC 16 Z9 16 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 FEB 20 PY 2003 VL 584 IS 2 BP 832 EP 842 DI 10.1086/345847 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 643WG UT WOS:000180884100028 ER PT J AU Prato, L Greene, TP Simon, M AF Prato, L Greene, TP Simon, M TI Astrophysics of young star binaries SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : general; stars : low-mass, brown dwarfs; stars : pre-main-sequence ID T-TAURI STARS; MAIN-SEQUENCE STARS; LOW-MASS STARS; RHO-OPHIUCHI CLOUD; SPECTRAL ENERGY-DISTRIBUTIONS; INFRARED-TELESCOPE-FACILITY; CENTAURUS OB ASSOCIATION; TIP-TILT SECONDARY; X-RAY SOURCES; STELLAR OBJECTS AB This paper describes our study of the astrophysics of individual components in close pre-main-sequence binaries. We observed both stars in 17 systems, located in four nearby star-forming regions, using low-resolution (R = 760) infrared spectroscopy and photometry. For 29 components we detected photospheric absorption lines and were able to determine spectral type, extinction, K-band excess, and luminosity. The other five objects displayed featureless or pure emission line spectra. In similar to50% of the systems, the extinction and K-band excess of the primary stars dominate those of the secondaries. Masses and ages were determined for these 29 objects by placing them on the H-R diagram, overlaid with theoretical pre-main-sequence tracks. Most of the binaries appear to be coeval. The ages span 5 x 10(5) to 1 x 10(7) yr. The derived masses range from the substellar, 0.06 M., to 2.5 M., and the mass ratios from M-2/M-1 = 0.04 to 1.0. Fourteen stars show evidence of circumstellar disks. The K-band excess is well correlated with the K-L color for stars with circumstellar material. C1 Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. SUNY Stony Brook, Dept Phys & Astron, Stony Brook, NY 11794 USA. RP Prato, L (reprint author), Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. NR 91 TC 97 Z9 97 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 FEB 20 PY 2003 VL 584 IS 2 BP 853 EP 874 DI 10.1086/345828 PN 1 PG 22 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 643WG UT WOS:000180884100030 ER PT J AU Mitrofanov, IG Sanin, AB Anfimov, DS Litvak, ML Briggs, MS Paciesas, WS Pendleton, GN Preece, RD Meegan, CA AF Mitrofanov, IG Sanin, AB Anfimov, DS Litvak, ML Briggs, MS Paciesas, WS Pendleton, GN Preece, RD Meegan, CA TI Comparison of redshift-known gamma-ray bursts with the main groups of bright BATSE events SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts ID PEAK; DISTRIBUTIONS; INTENSITY; TIME AB The small reference sample of six BATSE gamma-ray bursts with known redshifts from optical afterglows is compared with a comparison group of the 218 brightest BATSE bursts. These two groups are shown to be consistent both with respect to the distributions of the spectral peak parameter in the observer's frame and also with respect to the distributions of the frame-independent cosmological invariant parameter (CIP). Using the known values of the redshifts (z) for the reference sample, the rest-frame distribution of spectral parameters is built. The deredshifted distribution of the spectral parameters of the reference sample is compared with distribution of these parameters for the comparison group after deredshifting by the factor 1/(1 + z), with z a free parameter. Requiring consistency between these two distributions produces a collective estimation of the best fitting redshifts for the comparison group z = 1.8-3.6. These values can be considered as the average cosmological redshift of the sources of the brightest BATSE bursts. The most probable value of the peak energy of the spectrum in the rest frame is 920 keV. C1 Moscow Space Res Inst, Moscow 117810, Russia. Univ Alabama, Dept Phys, Huntsville, AL 35899 USA. Natl Space Sci & Technol Ctr, Huntsville, AL 35812 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Mitrofanov, IG (reprint author), Moscow Space Res Inst, Profsojuznaya Str 84-32, Moscow 117810, Russia. OI Preece, Robert/0000-0003-1626-7335 NR 28 TC 2 Z9 2 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 20 PY 2003 VL 584 IS 2 BP 904 EP 910 DI 10.1086/345805 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 643WG UT WOS:000180884100034 ER PT J AU Price, PA Kulkarni, SR Schmidt, BP Galama, TJ Bloom, JS Berger, E Frail, DA Djorgovski, SG Fox, DW Henden, AA Klose, S Harrison, FA Reichart, DE Sari, R Yost, SA Axelrod, TS McCarthy, P Holtzman, J Halpern, JP Kimble, RA Wheeler, JC Chevalier, RA Hurley, K Ricker, GR Costa, E Frontera, F Piro, L AF Price, PA Kulkarni, SR Schmidt, BP Galama, TJ Bloom, JS Berger, E Frail, DA Djorgovski, SG Fox, DW Henden, AA Klose, S Harrison, FA Reichart, DE Sari, R Yost, SA Axelrod, TS McCarthy, P Holtzman, J Halpern, JP Kimble, RA Wheeler, JC Chevalier, RA Hurley, K Ricker, GR Costa, E Frontera, F Piro, L TI GRB 010921: Strong limits on an underlying supernova from the Hubble Space Telescope SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts ID GAMMA-RAY BURST; 25 APRIL 1998; DIGITAL SKY SURVEY; OPTICAL AFTERGLOW; HOST GALAXY; ULTRAVIOLET EXTINCTION; BAND OBSERVATIONS; LIGHT-CURVE; GRB 970228; JET AB GRB 010921 was the first HETE-2 gamma-ray burst (GRB) to be localized via its afterglow emission. The low redshift of the host galaxy, z = 0.451, prompted us to undertake intensive multicolor observations with the Hubble Space Telescope with the goal of searching for an underlying supernova (SN) component. We do not detect any coincident SN to a limit 1.33 mag fainter than SN 1998bw at 99.7% confidence, making this one of the most sensitive searches for an underlying SN. Analysis of the afterglow data allows us to infer that the GRB was situated behind a net extinction (Milky Way and the host galaxy) of A(V) similar to 1.8 mag in the observer frame. Thus, had it not been for such heavy extinction, our data would have allowed us to probe for an underlying SN with brightness approaching those of more typical Type Ib/c SNe. C1 Australian Natl Univ, 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. USN Observ, Univ Space Res Assoc, Flagstaff, AZ 86002 USA. Karl Schwarzschild Observ, Thuringer Landessternwarte Tautenburg, D-07778 Tautenburg, Germany. Carnegie Inst Washington Observ, Pasadena, CA 91101 USA. New Mexico State Univ, Dept Astron, Las Cruces, NM 88003 USA. Columbia Univ, Columbia Astrophys Lab, New York, NY 10027 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Univ Texas, Dept Astron, Austin, TX 78712 USA. Univ Virginia, Dept Astron, Charlottesville, VA 22903 USA. Univ Calif Berkeley, Dept Astron, Space Sci Lab, Berkeley, CA 94720 USA. MIT, Ctr Space Res, Cambridge, MA 02139 USA. CNR, Ist Astrofis Spaziale & Fis Cosm, I-40129 Bologna, Italy. CNR, Ist Astrofis Spaziale, Area Tor Vergata, I-00133 Rome, Italy. Univ Ferrara, Dipartimento Fis, I-44100 Ferrara, Italy. RP Price, PA (reprint author), Australian Natl Univ, 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; 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 57 TC 25 Z9 25 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 FEB 20 PY 2003 VL 584 IS 2 BP 931 EP 936 DI 10.1086/345734 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 643WG UT WOS:000180884100036 ER PT J AU Akiyama, S Wheeler, JC Meier, DL Lichtenstadt, I AF Akiyama, S Wheeler, JC Meier, DL Lichtenstadt, I TI The magnetorotational instability in core-collapse supernova explosions SO ASTROPHYSICAL JOURNAL LA English DT Article DE instabilities; MHD; supernovae : general ID GAMMA-RAY BURSTS; MAGNETIZED NEUTRON-STARS; O-TYPE STARS; ROTATIONAL VELOCITIES; ACCRETION DISKS; MASSIVE STARS; CASSIOPEIA-A; X-RAY; RADIO JETS; EVOLUTION AB We investigate the action of the magnetorotational instability (MRI) in the context of iron-core collapse. Exponential growth of the field on the timescale Omega(-1) by the MRI will dominate the linear growth process of field-line "wrapping" with the same characteristic time. We examine a variety of initial rotation states, with solid-body rotation or a gradient in rotational velocity, that correspond to models in the literature. A relatively modest value of the initial rotation, a period of similar to10 s, will give a very rapidly rotating proto neutron star and hence strong differential rotation with respect to the infalling matter. We assume conservation of angular momentum on spherical shells. Rotational distortion and the dynamic feedback of the magnetic field are neglected in the subsequent calculation of rotational velocities. In our rotating and collapsing conditions, a seed field is expected to be amplified by the MRI and to grow exponentially to a saturation field. Results are discussed for two examples of saturation fields, a fiducial field that corresponds to v(A) = rOmega and a field that corresponds to the maximum growing mode of the MRI. We find, as expected, that the shear is strong at the boundary of the newly formed proto neutron star and, unexpectedly, that the region within the stalled shock can be subject to strong MHD activity. Modest initial rotation velocities of the iron core result in sub-Keplerian rotation and a sub-equipartition magnetic field that nevertheless produce substantial MHD luminosity and hoop stresses: saturation fields of order 10(15)-10(16) G can develop similar to300 ms after bounce with an associated MHD luminosity of similar to10(52) ergs s(-1). Bipolar flows driven by this MHD power can affect or even cause the explosions associated with core-collapse supernovae. C1 Univ Texas, Dept Astron, Austin, TX 78712 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Hebrew Univ Jerusalem, Jerusalem, Israel. RP Akiyama, S (reprint author), Univ Texas, Dept Astron, RLM 15308, Austin, TX 78712 USA. NR 76 TC 251 Z9 252 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 FEB 20 PY 2003 VL 584 IS 2 BP 954 EP 970 DI 10.1086/344135 PN 1 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 643WG UT WOS:000180884100038 ER PT J AU Wilson, CA Finger, MH Coe, MJ Negueruela, I AF Wilson, CA Finger, MH Coe, MJ Negueruela, I TI XTE J1946+274 = GRO J1944+26: An enigmatic Be/X-ray binary SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; binaries : close; pulsars : individual (GRO J1944+26; XTE J1946+274); X-rays : binaries ID QUASI-PERIODIC OSCILLATIONS; WIND-ACCRETION SIMULATIONS; PULSAR EXO-2030+375; TIMING EXPLORER; OUTBURSTS; ORBIT; STARS; PERFORMANCE; DISCOVERY; GRADIENTS AB XTE J1946+ 274 = GRO J1944+ 26 is a 15.8 s Be/X-ray pulsar discovered simultaneously in 1998 September with the Burst and Transient Source Experiment (BATSE) on the Compton Gamma Ray Observatory (CGRO) and the All-Sky Monitor (ASM) on the Rossi X-Ray Timing Explorer (RXTE). Here we present new results from BATSE and RXTE including a pulse timing analysis, spectral analysis, and evidence for an accretion disk. Our pulse timing analysis yielded an orbital period of 169.2 days, a moderate eccentricity of 0.33, and implied a mass function of 9.7 M.. We observed evidence for an accretion disk, a correlation between measured spin-up rate and flux, which was fitted to obtain a distance estimate of 9.5 +/- 2.9 kpc. XTE J1946+ 274 remained active from 1998 September to 2001 July, undergoing 13 outbursts that were not locked in orbital phase. Comparing RXTE Proportional Counter Array observations from the initial bright outburst in 1998 and the last pair of outbursts in 2001, we found energy and intensity-dependent pulse pro le variations in both outbursts and hardening spectra with increasing intensity during the fainter 2001 outbursts. In 2001 July, optical Halpha observations indicated that a density perturbation appeared in the Be disk as the X-ray outbursts ceased. We propose that the equatorial plane of the Be star is inclined with respect to the orbital plane in this system and that this inclination may be a factor in the unusual outburst behavior of the system. C1 NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc,Space Sci Res Ctr SD 50, Natl Space Sci & Technol Ctr, Huntsville, AL 35805 USA. Univ Southampton, Dept Phys & Astron, Southampton SO17 1BJ, Hants, England. Observ Strasbourg, F-67000 Strasbourg, France. RP Wilson, CA (reprint author), NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc,Space Sci Res Ctr SD 50, Natl Space Sci & Technol Ctr, 320 Sparkman Dr, Huntsville, AL 35805 USA. RI Negueruela, Ignacio/L-5483-2014 OI Negueruela, Ignacio/0000-0003-1952-3680 NR 46 TC 31 Z9 31 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 FEB 20 PY 2003 VL 584 IS 2 BP 996 EP 1007 DI 10.1086/345791 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 643WG UT WOS:000180884100042 ER PT J AU Richardson, LJ Deming, D Wiedemann, G Goukenleuque, C Steyert, D Harrington, J Esposito, LW AF Richardson, LJ Deming, D Wiedemann, G Goukenleuque, C Steyert, D Harrington, J Esposito, LW TI Infrared observations during the secondary eclipse of HD 209458b. I. 3.6 micron occultation spectroscopy using the very large telescope SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : eclipsing; planetary systems; stars : individual (HD209458); techniques : spectroscopic ID GIANT PLANET ATMOSPHERES; TRANSMISSION SPECTRA; TRANSITING PLANET; SEARCH; HD-209458 AB We search for an infrared signature of the transiting extrasolar planet HD 209458b during secondary eclipse. Our method, which we call "occultation spectroscopy", searches for the disappearance and reappearance of weak spectral features due to the exoplanet as it passes behind the star and later reappears. We argue that at the longest infrared wavelengths, this technique becomes preferable to conventional "transit spectroscopy". We observed the system in the wing of the strong nu(3) band of methane near 3.6 mum during two secondary eclipses, using the VLT/ISAAC spectrometer at a spectral resolution of 3300. Our analysis, which utilizes a model template spectrum, achieves sufficient precision to expect detection of the spectral structure predicted by an irradiated, low-opacity (cloudless), low-albedo, thermochemical equilibrium model for the exoplanet atmosphere. However, our observations show no evidence for the presence of this spectrum from the exoplanet, with the statistical significance of the nondetection depending on the timing of the secondary eclipse, which depends on the assumed value for the orbital eccentricity. Our results reject certain specific models of the atmosphere of HD 209458b as inconsistent with our observations at the 3 sigma level, given assumptions about the stellar and planetary parameters. C1 NASA, Goddard Space Flight Ctr, Planetary Syst Branch, Greenbelt, MD 20771 USA. Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80303 USA. Univ Colorado, Dept Phys, Boulder, CO 80309 USA. Inst Astrophys, D-07745 Jena, Germany. Univ Sternwarte, D-07745 Jena, Germany. Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21250 USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. RP Richardson, LJ (reprint author), NASA, Goddard Space Flight Ctr, Planetary Syst Branch, Code 693, Greenbelt, MD 20771 USA. RI Harrington, Joseph/E-6250-2011; OI Harrington, Joseph/0000-0002-8955-8531 NR 29 TC 39 Z9 40 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 FEB 20 PY 2003 VL 584 IS 2 BP 1053 EP 1062 DI 10.1086/345813 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 643WG UT WOS:000180884100049 ER PT J AU Kahler, SW Reames, DV AF Kahler, SW Reames, DV TI Solar energetic particle production by coronal mass ejection driven shocks in solar fast-wind regions SO ASTROPHYSICAL JOURNAL LA English DT Article DE solar wind; Sun : coronal mass ejections (CMEs) Sun : particle emission ID ELEMENT ABUNDANCES; EMPIRICAL-MODEL; ULYSSES; POLAR; ACCELERATION; SOHO; INSTRUMENT; SPACECRAFT; TRANSPORT; SPECTRA AB Gradual solar energetic particle (SEP) events at 1 AU are produced by coronal/interplanetary shocks driven by coronal mass ejections (CMEs). Fast (v(CME) greater than or similar to 900 km s(-1)) CMEs might produce stronger shocks in solar slow-wind regions, where the flow and fast-mode MHD wave speeds are low, than in fast-wind regions, where those speeds are much higher. At 1 AU the O+7/O+6 ratios distinguish between those two kinds of wind streams. We use the 20 MeV proton event intensities from the EPACT instrument on Wind, the associated CMEs observed with the LASCO coronagraph on SOHO, and the ACE SWICS solar wind values of O+7/O+6 to look for variations of peak SEP intensities as a function of O+7/O+6. No significant dependence of the SEP intensities on O+7/O+6 is found for either poorly connected or well-connected CME source regions or for different CME speed ranges. However, in the 3 yr study period we find only five cases of SEP events in fast wind, defined by regions of O+7/O+6<0.15. We suggest that in coronal holes SEP acceleration may take place only in the plume regions, where the flow and Alfven speeds are low. A broad range of angular widths are associated with fast (v(CME) &GE; 900 km s(-1)) CMEs, but we find that no fast CMEs with widths less than 60&DEG; are associated with SEP events. On the other hand, nearly all fast halo CMEs are associated with SEP events. Thus, the CME widths are more important in SEP production than previously thought, but the speed of the solar wind source regions in which SEPs are produced may not be a factor. C1 USAF, Res Lab, Space Vehicles Directorate, Hanscom AFB, MA 01731 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Kahler, SW (reprint author), USAF, Res Lab, Space Vehicles Directorate, 29 Randolph Rd, Hanscom AFB, MA 01731 USA. NR 56 TC 42 Z9 43 U1 1 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 20 PY 2003 VL 584 IS 2 BP 1063 EP 1070 DI 10.1086/345780 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 643WG UT WOS:000180884100050 ER PT J AU Brown, TM Ferguson, HC Smith, E Bowers, CW Kimble, RA Renzini, A Rich, RM AF Brown, TM Ferguson, HC Smith, E Bowers, CW Kimble, RA Renzini, A Rich, RM TI Far-ultraviolet emission from elliptical galaxies at z=0.33 SO ASTROPHYSICAL JOURNAL LA English DT Article DE cooling flows; galaxies : evolution; galaxies : stellar content; ultraviolet : galaxies ID COLOR-MAGNITUDE RELATION; DISTANT CLUSTERS; EVOLUTION; CL-1358+62 AB We present far-UV images of the rich galaxy cluster ZwCl 1358.1+6245, taken with the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope (HST). When combined with archival HST observations, our data provide a measurement of the UV-to-optical flux ratio in eight early-type galaxies at z = 0.33. Because the UV flux originates in a population of evolved, hot, horizontal-branch (HB) stars, this ratio is 0.33 potentially one of the most sensitive tracers of age in old populations- it is expected to fade rapidly with look-back time. We find that the UV emission in these galaxies, at a look-back time of 3.9 Gyr, is significantly weaker than it is in the current epoch, yet it is similar to that in galaxies at a look-back time of 5.6 Gyr. Taken at face value, these measurements imply different formation epochs for the massive elliptical galaxies in these clusters, but an alternative explanation is a "floor" in the UV emission due to a dispersion in the parameters that govern HB morphology. C1 Space Telescope Sci Inst, Baltimore, MD 21218 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. European So Observ, D-85748 Garching, Germany. Univ Calif Los Angeles, Div Astron & Astrophys, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. RP Brown, TM (reprint author), Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA. OI Brown, Thomas/0000-0002-1793-9968 NR 20 TC 30 Z9 30 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 20 PY 2003 VL 584 IS 2 BP L69 EP L72 DI 10.1086/374035 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 643WH UT WOS:000180884400007 ER PT J AU Kim, D Park, DY Yoo, BY Sumodjo, PTA Myung, NV AF Kim, D Park, DY Yoo, BY Sumodjo, PTA Myung, NV TI Magnetic properties of nanocrystalline iron group thin film alloys electrodeposited from sulfate and chloride baths SO ELECTROCHIMICA ACTA LA English DT Article DE electrodeposition; magnetic films; NiCo alloys; CoFe alloys; CoNiFe alloys; magnetic properties ID ANOMALOUS CODEPOSITION; NICKEL-IRON; CONIFE FILM; ELECTROCHEMICAL PREPARATION; CORROSION PROPERTIES; MATHEMATICAL-MODEL; SULFUR INCLUSION; FLUX DENSITY; GROUP METALS; SOFT AB Systematic studies of iron group binary (NiCo and CoFe) and ternary (CoNiFe) thin film alloys relating their magnetic properties with film composition, grain size and the corresponding crystal structure were investigated. Anions influence current efficiencies, magnetic properties, surface morphology and phases of electrodeposited films. Higher current efficiencies in chloride baths compared to sulfate baths were observed for CoFe, NiCo and CoNiFe alloys. The higher deposition current efficiencies in chloride baths were attributed to a catalytic effect. Anion types in CoFe and CoNiFe thin film alloys influenced the microstructures and the resulting magnetic properties (coercivity and squareness). The microstructures of NiCo alloys depend on the deposit Co contents rather than anion types. The surface morphologies of CoFe, NiCo and CoNiFe thin films were independent of anion types. CoFe deposits exhibited relatively smooth surface morphology and turned into fine crystallites with increasing solution Fe+2 concentration. NiCo deposits showed very smooth surface morphology. CoNiFe deposits had the surface morphology of polyhedral crystallites. The deposit Fe content in CoFe electrodeposits linearly increased with increasing solution Fe+2 concentration for both chloride and sulfate baths. Similar linear behavior of deposit Co contents was observed in NiCo electrodeposits. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Los Angeles, Dept Chem Engn, Los Angeles, CA 90095 USA. RP Myung, NV (reprint author), Jet Prop Lab, MEMS Technol Grp, 4800 Oak Glove Blvd, Pasadena, CA 91109 USA. RI Sumodjo, Paulo Teng An/F-2049-2014; Institute of Chemistry - USP, Dept. of Chemistry/B-8988-2012 NR 34 TC 97 Z9 100 U1 1 U2 22 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0013-4686 J9 ELECTROCHIM ACTA JI Electrochim. Acta PD FEB 20 PY 2003 VL 48 IS 7 BP 819 EP 830 AR PII S0013-4686(02)00773-9 DI 10.1016/S0013-4686(02)00773-9 PG 12 WC Electrochemistry SC Electrochemistry GA 645TP UT WOS:000180995700005 ER PT J AU Savchenkov, AA Ilchenko, VS Matsko, AB Maleki, L AF Savchenkov, AA Ilchenko, VS Matsko, AB Maleki, L TI Tunable filter based on whispering gallery modes SO ELECTRONICS LETTERS LA English DT Article ID DENSE WDM NETWORKS AB A narrowband, widely tunable filter based on a whispering gallery mode LiNbO3 cavity with 10 GHz free spectral range is proposed and demonstrated. The filter operates at 1.55 mum with 30 MHz bandwidth and can be electro-optically tuned at 10 GHz in the linear regime with approximately 40 MHz/V tuning rate. With this filter, we have demonstrated 12 dB fibre-to-fibre insertion loss and 30 mus tuning speed. 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. RI Matsko, Andrey/A-1272-2007 NR 4 TC 41 Z9 41 U1 2 U2 7 PU IEE-INST ELEC ENG PI HERTFORD PA MICHAEL FARADAY HOUSE SIX HILLS WAY STEVENAGE, HERTFORD SG1 2AY, ENGLAND SN 0013-5194 J9 ELECTRON LETT JI Electron. Lett. PD FEB 20 PY 2003 VL 39 IS 4 BP 389 EP 391 DI 10.1049/el:20030229 PG 3 WC Engineering, Electrical & Electronic SC Engineering GA 655BZ UT WOS:000181532600033 ER PT J AU Montesi, LGJ Zuber, MT AF Montesi, LGJ Zuber, MT TI Spacing of faults at the scale of the lithosphere and localization instability: 1. Theory SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article DE faults; folds; buckling; instability analysis; fault spacing; rheology ID CENTRAL INDIAN-OCEAN; CONTINENTAL LITHOSPHERE; NUMERICAL-SIMULATION; CENTRAL-ASIA; INTRAPLATE DEFORMATION; SHEAR ZONES; MODEL; EXTENSION; RHEOLOGY; BASIN AB [1] Large-scale tectonic structures such as orogens and rifts commonly display regularly spaced faults and/or localized shear zones. To understand how fault sets organize with a characteristic spacing, we present a semianalytical instability analysis of an idealized lithosphere composed of a brittle layer over a ductile half-space undergoing horizontal shortening or extension. The rheology of the layer is characterized by an effective stress exponent, ne. The layer is pseudoplastic if 1/n(e) = 0 and forms localized structures if 1/n(e) < 0. Two instabilities grow simultaneously in this model: the "buckling/necking instability'' that produces broad undulations of the brittle layer as a whole, and the "localization instability'' that produces a spatially periodic pattern of faulting. The latter appears only if the material in the brittle layer weakens in response to a local perturbation of strain rate, as indicated by 1/n(e) < 0. Fault spacing scales with the thickness of the brittle layer and depends on the efficiency of localization. Localization is more efficient for more negative 1/n(e), leading to more widely spaced faults. The fault spacing is related to the wavelength at which different deformation modes within the layer enter a resonance that exists only if 1/n(e) < 0. Depth-dependent viscosity and the model density offset the instability wavelengths by an amount a(L) that we determine empirically. The wave number of the localization instability, is k(j)(L) = pi(j + a(L))( -1/n(e))(-1/2)/H, with H the thickness of the brittle layer, j an integer, and 1/4 < a(L) < 1/2 if the strength of the layer increases with depth and the strength of the substrate decreases with depth. C1 MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. RP Montesi, LGJ (reprint author), Woods Hole Oceanog Inst, Dept Geol & Geophys, MS 22, Woods Hole, MA 02543 USA. EM montesi@whoi.edu; zuber@mit.edu RI Montesi, Laurent/C-5216-2009 OI Montesi, Laurent/0000-0002-3519-1412 NR 85 TC 20 Z9 20 U1 0 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 FEB 20 PY 2003 VL 108 IS B2 AR 2110 DI 10.1029/2002JB001923 PG 21 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 663BP UT WOS:000181985500004 ER PT J AU Montesi, LGJ Zuber, MT AF Montesi, LGJ Zuber, MT TI Spacing of faults at the scale of the lithosphere and localization instability: 2. Application to the Central Indian Basin SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article DE faults; Central Indian Basin; fault spacing; folds; strength envelope; diffuse plate boundary ID INDO-AUSTRALIAN PLATE; INTRAPLATE DEFORMATION; OCEANIC LITHOSPHERE; HEAT-FLOW; RHEOLOGY; TECTONICS; STRESS; EARTHQUAKE; SEISMICITY; EVOLUTION AB [1] Tectonic deformation in the Central Indian Basin (CIB) is organized at two spatial scales: long-wavelength (similar to 200 km) undulations of the basement and regularly spaced faults. The fault spacing of order 7-11 km is too short to be explained by lithospheric buckling. We show that the localization instability derived by Montesi and Zuber [2003] provides an explanation for the fault spacing in the CIB. Localization describes how deformation focuses on narrow zones analogous to faults. The localization instability predicts that localized shear zones form a regular pattern with a characteristic spacing as they develop. The theoretical fault spacing is proportional to the depth to which localization occurs. It also depends on the strength profile and on the effective stress exponent, ne, which is a measure of localization efficiency in the brittle crust and upper mantle. The fault spacing in the CIB can be matched by n(e) similar to -300 if the faults reach the depth of the brittle ductile transition (BDT) around 40 km or n(e) similar to - 100 if the faults do not penetrate below 10 km. These values of ne are compatible with laboratory data on frictional velocity weakening. Many faults in the CIB were formed during seafloor spreading. The preexisting faults near target locations separated by the wavelength of the localization instability were preferentially reactivated during the current episode of compressive tectonics. The long-wavelength undulations may result from the interaction between buckling and localization. C1 MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. RP Montesi, LGJ (reprint author), Woods Hole Oceanog Inst, Dept Geol & Geophys, MS 22, Woods Hole, MA 02543 USA. EM montesi@whoi.edu; zuber@mit.edu RI Montesi, Laurent/C-5216-2009 OI Montesi, Laurent/0000-0002-3519-1412 NR 72 TC 17 Z9 17 U1 0 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 FEB 20 PY 2003 VL 108 IS B2 AR 2111 DI 10.1029/2002JB001924 PG 17 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 663BP UT WOS:000181985500005 ER PT J AU Frey, HU Immel, TJ Lu, G Bonnell, J Fuselier, SA Mende, SB Hubert, B Ostgaard, N Le, G AF Frey, HU Immel, TJ Lu, G Bonnell, J Fuselier, SA Mende, SB Hubert, B Ostgaard, N Le, G TI Properties of localized, high latitude, dayside aurora SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE aurora; electron precipitation; high latitude; interplanetary magnetic field; ionosphere; acceleration ID INTERPLANETARY MAGNETIC-FIELD; DYNAMIC CUSP AURORA; PROTON AURORA; POLAR-REGION; LYMAN-ALPHA; IMAGE-FUV; CONVECTION; NORTHWARD; FEATURES; FORMS AB [1] The FUV instrument on the IMAGE spacecraft frequently observes intense ultraviolet (UV) emission from a localized dayside region poleward of the general auroral oval location. One type of these emissions has been described as the signature of direct proton precipitation into the cusp after lobe reconnection during northward interplanetary magnetic field (IMF) and high solar wind dynamic pressure periods [Frey et al., 2002]. Here we describe a completely different type of high latitude aurora, which does not show any signature of precipitating protons. It also occurs during northward IMF conditions however, only during periods of very low solar wind dynamic pressure. It occurs at a much higher geomagnetic latitude than the normal cusp location and only during periods of positive IMF By. The intensity of the UV emission is somewhat anti-correlated with the solar wind dynamic pressure, much in contrast to the cusp emission. The brightness of the localized emission changes rapidly on time scales between 30 and 70 minutes without corresponding changes in solar wind properties. Coincident measurements by the FAST spacecraft verify that this is not the cusp, that ion precipitation is absent in these regions, and that strong precipitation of field-aligned accelerated electrons causes the aurora. We interpret this aurora as the optical signature of electron precipitation in the upward leg of a current system which closes the downward leg of the current system into the cusp in the ionosphere. C1 Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Univ Liege, LPAP, B-4000 Liege, Belgium. NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. NCAR, Altitude Observ, Boulder, CO 80301 USA. Lockheed Martin ATC, Palo Alto, CA 94304 USA. RP Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. EM hfrey@ssl.berkeley.edu; ganglu@hao.ucar.edu; stephen.a.fuselier@lmco.com; benoit@astro.ulg.ac.be; Guan.Le@gsfc.nasa.gov RI Lu, Gang/A-6669-2011; Le, Guan/C-9524-2012; OI Le, Guan/0000-0002-9504-5214; Frey, Harald/0000-0001-8955-3282 NR 34 TC 16 Z9 16 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9380 EI 2169-9402 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD FEB 19 PY 2003 VL 108 IS A4 AR 8008 DI 10.1029/2002JA009332 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 663BY UT WOS:000181986600001 ER PT J AU Kondo, Y Toon, OB Irie, H Gamblin, B Koike, M Takegawa, N Tolbert, MA Hudson, PK Viggiano, AA Avallone, LM Hallar, AG Anderson, BE Sachse, GW Vay, SA Hunton, DE Ballenthin, JO Miller, TM AF Kondo, Y Toon, OB Irie, H Gamblin, B Koike, M Takegawa, N Tolbert, MA Hudson, PK Viggiano, AA Avallone, LM Hallar, AG Anderson, BE Sachse, GW Vay, SA Hunton, DE Ballenthin, JO Miller, TM TI Uptake of reactive nitrogen on cirrus cloud particles in the upper troposphere and lowermost stratosphere SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID CHEMISTRY MODEL; NITRIC-ACID; WAVE-CLOUD; ICE; TEMPERATURES; HNO3 AB NOy ( total reactive nitrogen) contained in ice particles was measured on board the NASA DC-8 aircraft in the Arctic in January and March 2000. During some of the flights, the DC-8 encountered widespread cirrus clouds. Large quantities of ice particles were observed at 8-12 km and particulate NOy showed large increases. The data indicate that the amount of NOy covering the cirrus ice particles strongly depended on temperature. Similar measurements were made in the upper troposphere over the tropical Pacific Ocean in August-September 1998 and 1999. The data obtained in the Arctic and tropics show very limited uptake of NOy on ice at temperatures above 215 K. C1 Univ Tokyo, Adv Sci & Technol Res Ctr, Tokyo 1538904, Japan. Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80309 USA. Natl Inst Environm Studies, Tsukuba, Ibaraki, Japan. Univ Tokyo, Dept Earth & Planetary Sci, Tokyo 1130033, Japan. Univ Colorado, Dept Chem & Biochem, CIRES, Boulder, CO 80309 USA. USAF, Res Lab, VSBXT, Hanscom AFB, MA 01731 USA. NASA, Div Atmospher Sci, Langley Res Ctr, Hampton, VA 23681 USA. RP Kondo, Y (reprint author), Univ Tokyo, Adv Sci & Technol Res Ctr, Tokyo 1538904, Japan. RI Koike, Makoto/F-4366-2011; Kondo, Yutaka/D-1459-2012; Hallar, Anna Gannet/I-9104-2012 OI Hallar, Anna Gannet/0000-0001-9972-0056 NR 17 TC 28 Z9 29 U1 0 U2 9 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 FEB 18 PY 2003 VL 30 IS 4 AR 1154 DI 10.1029/2002GL016539 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 663AN UT WOS:000181982800003 ER PT J AU Bergstrom, RW Pilewskie, P Schmid, B Russell, PB AF Bergstrom, RW Pilewskie, P Schmid, B Russell, PB TI Estimates of the spectral aerosol single scattering albedo and aerosol radiative effects during SAFARI 2000 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE aerosols; absorption; black carbon; biomass burning ID OPTICAL-PROPERTIES; ABSORPTION; DEPENDENCE; PARTICLES AB [1] Using measurements of the spectral solar radiative flux and optical depth for 2 days (24 August and 6 September 2000) during the SAFARI 2000 intensive field experiment and a detailed radiative transfer model, we estimate the spectral single scattering albedo of the aerosol layer. The single scattering albedo is similar on the 2 days even though the optical depth for the aerosol layer was quite different. The aerosol single scattering albedo was between 0.85 and 0.90 at 350 nm, decreasing to 0.6 in the near infrared. The magnitude and decrease with wavelength of the single scattering albedo are consistent with the absorption properties of small black carbon particles. We estimate the uncertainty in the single scattering albedo due to the uncertainty in the measured fractional absorption and optical depths. The uncertainty in the single scattering albedo is significantly less on the high-optical-depth day (6 September) than on the low-optical-depth day (24 August). On the high-optical-depth day, the uncertainty in the single scattering albedo is 0.02 in the midvisible whereas on the low-optical-depth day the uncertainty is 0.08 in the midvisible. On both days, the uncertainty becomes larger in the near infrared. We compute the radiative effect of the aerosol by comparing calculations with and without the aerosol. The effect at the top of the atmosphere (TOA) is to cool the atmosphere by 13 W m(-2) on 24 August and 17 W m(-2) on 6 September. The effect on the downward flux at the surface is a reduction of 57 W m(-2) on 24 August and 200 W m(-2) on 6 September. The aerosol effect on the downward flux at the surface is in good agreement with the results reported from the Indian Ocean Experiment (INDOEX). C1 Bay Area Environm Res Inst, Sonoma, CA 95476 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Bergstrom, RW (reprint author), Bay Area Environm Res Inst, Sonoma, CA 95476 USA. EM bergstro@sky.arc.nasa.gov NR 25 TC 64 Z9 64 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 FEB 18 PY 2003 VL 108 IS D13 AR 8474 DI 10.1029/2002JD002435 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 663BC UT WOS:000181984300002 ER PT J AU Nsumei, PA Huang, X Reinisch, BW Song, P Vasyliunas, VM Green, JL Fung, SF Benson, RF Gallagher, DL AF Nsumei, PA Huang, X Reinisch, BW Song, P Vasyliunas, VM Green, JL Fung, SF Benson, RF Gallagher, DL TI Electron density distribution over the northern polar region deduced from IMAGE/radio plasma imager sounding SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE polar cap; density distribution; active experiment; radio sounding; multivariate regression; geomagnetic activity ID MAGNETIC-FIELD; SATELLITE; WIND; CAP AB [1] Electron density N-e distributions in the northern polar region are determined from 1.4 to 5.0 R-E at invariant latitudes greater than 70degrees using the radio plasma imager (RPI) on the IMAGE satellite over the period from June 2000 to November 2001. An empirical N-e model in this region is derived as a function of radial distance and geomagnetic activity. A power law with a power index of -5.09 +/- 0.03 describes the variation of N-e with radial distance. The N-e appears to increase exponentially with the Kp index. The altitude dependence of the empirical model at low geomagnetic activity is qualitatively consistent with previous models derived from the ISIS 1 and the Dynamic Explorer 1 spacecraft. C1 Univ Massachusetts, Ctr Atmospher Res, Environm Earth & Atmospher Sci, Lowell, MA 01854 USA. Max Planck Inst Aeron, D-37191 Katlenburg Lindau, Germany. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Nsumei, PA (reprint author), Univ Massachusetts, Ctr Atmospher Res, Environm Earth & Atmospher Sci, Lowell, MA 01854 USA. RI Fung, Shing/F-5647-2012 NR 31 TC 30 Z9 30 U1 1 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD FEB 18 PY 2003 VL 108 IS A2 AR 1078 DI 10.1029/2002JA009616 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 663BT UT WOS:000181985800001 ER PT J AU Abdeldayem, H Frazier, DO Paley, MS AF Abdeldayem, H Frazier, DO Paley, MS TI An all-optical picosecond switch in polydiacetylene SO APPLIED PHYSICS LETTERS LA English DT Article ID CONJUGATED POLYMER; NONLINEARITIES; GLASS AB A polydiacetylene derivative of 2-methyl-4-nitroaniline (PDAMNA) showed a picosecond switching property. This phenomenon was demonstrated by waveguiding a cw He-Ne laser collinearly with a mode-locked picosecond Nd:YAG laser at 532 nm through a hollow fiber coated on the inside with a thin film of PDAMNA. The Z-scan investigations of PDAMNA thin films revealed that the PDAMNA system is a three-level system and the switching is caused by excited state absorption of the He-Ne beam. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Space Res Assoc, Columbia, MD 21044 USA. RP Abdeldayem, H (reprint author), NASA, Goddard Space Flight Ctr, Code 554, Greenbelt, MD 20771 USA. NR 19 TC 21 Z9 21 U1 2 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 FEB 17 PY 2003 VL 82 IS 7 BP 1120 EP 1122 DI 10.1063/1.1543251 PG 3 WC Physics, Applied SC Physics GA 644KR UT WOS:000180917000040 ER PT J AU Bauschlicher, CW Ricca, A AF Bauschlicher, CW Ricca, A TI Conductivity at low temperatures, are the rings eclipsed or perpendicular? SO CHEMICAL PHYSICS LETTERS LA English DT Article AB For seven and nine tolane molecules, forming a T-shaped arrangement, the conformation with eclipsed rings on each tolane molecule is more stable than the one with rings perpendicular to each other on each tolane molecule. The implication for the low temperature conductivity measurements is discussed. (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. NR 8 TC 2 Z9 2 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 FEB 17 PY 2003 VL 369 IS 3-4 BP 415 EP 418 DI 10.1016/S0009-2614(02)02047-X PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 644ME UT WOS:000180921200024 ER PT J AU Tunstel, E Howard, A AF Tunstel, E Howard, A TI Approximate reasoning for safety and survivability of planetary rovers SO FUZZY SETS AND SYSTEMS LA English DT Article; Proceedings Paper CT 4th International FLINS Conference on Intelligent Techniques and Soft Computing in Nuclear Science and Engineering CY AUG 28-30, 2000 CL BRUGGE, BELGIUM DE approximate reasoning; fuzzy inference systems; robotics; planetary rovers; neural networks; vision-based control; off-road mobility ID TRACTION CONTROL; MOBILE ROBOT; FUZZY; VEHICLES; BRAKING; SYSTEM AB Operational safety and health monitoring are critical matters for autonomous planetary rovers operating on remote and challenging terrain. This paper describes rover safety issues and presents an approximate reasoning approach to maintaining vehicle safety in a navigational context. The proposed rover safety module is composed of two distinct behaviors: safe attitude (pitch and roll) management and safe traction management. Fuzzy logic implementations of these behaviors on outdoor terrain are presented. Sensing of vehicle safety coupled with visual neural network-based perception of terrain quality are used to infer safe speeds during rover traversal. In addition, approximate reasoning for self-regulation of internal operating conditions is briefly discussed. The core theoretical foundations of the applied soft computing techniques are presented and supported by descriptions of field tests and laboratory experimental results. For autonomous rovers, the approach provides intrinsic safety cognizance and a capacity for reactive mitigation of navigation risks. (C) 2002 Elsevier Science B.V. All rights reserved. C1 CALTECH, NASA, Jet Propuls Lab, Pasadena, CA 91109 USA. RP CALTECH, NASA, Jet Propuls Lab, Pasadena, CA 91109 USA. EM tunstel@robotics.jpl.nasa.gov NR 28 TC 4 Z9 5 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0165-0114 EI 1872-6801 J9 FUZZY SET SYST JI Fuzzy Sets Syst. PD FEB 16 PY 2003 VL 134 IS 1 BP 27 EP 46 AR PII S0165-0114(02)00228-2 DI 10.1016/S0165-0114(02)00228-2 PG 20 WC Computer Science, Theory & Methods; Mathematics, Applied; Statistics & Probability SC Computer Science; Mathematics GA 640HM UT WOS:000180682900003 ER PT J AU D'Aunno, DS Dougherty, AH DeBlock, HF Meck, JV AF D'Aunno, DS Dougherty, AH DeBlock, HF Meck, JV TI Effect of short- and long-duration spaceflight on QTc intervals in healthy astronauts SO AMERICAN JOURNAL OF CARDIOLOGY LA English DT Article AB Electrocardiographic and Holter monitor recordings obtained from astronauts before, during, and after short- and long-duration spaceflights reveal that long-duration spaceflight significantly prolongs cardiac conduction and repolarization. Long-duration flight is associated with significant QTc interval prolongation and may increase susceptibility to ventricular arrhythmias. C1 NASA, Lyndon B Johnson Space Ctr, Cardiovasc Lab, Space & Life Sci Directorate, Houston, TX 77058 USA. Baylor Coll Med, Natl Space Biomed Res Inst, Houston, TX 77030 USA. Univ Texas, Med Sch Houston, Houston, TX USA. Albany Med Coll, Albany, NY 12208 USA. RP Meck, JV (reprint author), NASA, Lyndon B Johnson Space Ctr, Cardiovasc Lab, Space & Life Sci Directorate, Mail Code SK,Bldg 261, Houston, TX 77058 USA. NR 8 TC 25 Z9 25 U1 1 U2 4 PU EXCERPTA MEDICA INC PI NEW YORK PA 650 AVENUE OF THE AMERICAS, NEW YORK, NY 10011 USA SN 0002-9149 J9 AM J CARDIOL JI Am. J. Cardiol. PD FEB 15 PY 2003 VL 91 IS 4 BP 494 EP + DI 10.1016/S0002-9149(02)03259-9 PG 5 WC Cardiac & Cardiovascular Systems SC Cardiovascular System & Cardiology GA 648LK UT WOS:000181152700030 PM 12586278 ER PT J AU Brandon, AD Walker, RJ Puchtel, IS Becker, H Humayun, M Revillon, S AF Brandon, AD Walker, RJ Puchtel, IS Becker, H Humayun, M Revillon, S TI Os-186-Os-187 systematics of Gorgona Island komatiites: implications for early growth of the inner core SO EARTH AND PLANETARY SCIENCE LETTERS LA English DT Article DE osmium; platinum; rhenium; komatiite ID OSMIUM ISOTOPIC COMPOSITIONS; PLATINUM-GROUP ELEMENTS; RE-OS SYSTEMATICS; EARTHS CORE; MANTLE INTERACTION; HAWAIIAN PICRITES; THERMAL EVOLUTION; GEOCHEMISTRY; PLUME; COLOMBIA AB The presence of coupled enrichments in Os-186/Os-188 and Os-187/Os-188 in some mantle-derived materials reflects long-term elevation of Pt/Os and Re/Os relative to the primitive upper mantle. New Os data for the 89 Ma Gorgona Island, Colombia komatiites indicate that these lavas are also variably enriched in Os-186 and Os-187, with Os-186/Os-188 ranging between 0.1198397 +/- 22 and 0.1198470 +/- 38, and with gamma(Os) correspondingly ranging from +0.15 to +4.4. These data define a linear trend that converges with the previously reported linear trend generated from data for modem Hawaiian picritic lavas and a sample from the ca. 251 Ma Siberian plume, to a common component with a Os-186/ Os-188 of approximately 0.119870 and gamma(Os) of +17.5. The convergence of these data to this Os isotopic composition may imply a single ubiquitous source in the Earth's interior that mixes with a variety of different mantle compositions distinguished by variations in yo, The Os-187- and 1116 Os-enriched component may have been generated via early crystallization of the solid inner core and consequent increases in Pt/Os and Re/Os in the liquid outer core, with time leading to suprachondritic Os-186/Os-188 and gamma(Os) in the outer core. The presence of Os from the outer core in certain portions of the mantle would require a mechanism that could transfer Os from the outer core to the lower mantle, and thence to the surface. If this is the process that generated the isotopic enrichments in the mantle sources of these plume-derived systems, then the current understanding of solid metal-liquid metal partitioning of Pt, Re and Os requires that crystallization of the inner core began prior to 3.5 Ga. Thus, the Os isotopic data reported here provide a new source of data to better constrain the timing of inner core formation, complementing magnetic field paleointensity measurements as data sources that constrain models based on secular cooling of the Earth. Published by Elsevier Science B.V. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Univ Maryland, Dept Geol, Isotope Geochem Lab, College Pk, MD 20742 USA. Univ Chicago, Dept Geophys Sci, Chicago, IL 60637 USA. Southampton Oceanog Ctr, Sch Ocean & Earth Sci, Southampton SO14 3ZH, Hants, England. RP Brandon, AD (reprint author), NASA, Lyndon B Johnson Space Ctr, Mail Code SR,Bldg 31,Room 114, Houston, TX 77058 USA. RI Revillon, Sidonie/A-7101-2010; Walker, Richard/K-6869-2016 OI Revillon, Sidonie/0000-0001-8370-4545; Walker, Richard/0000-0003-0348-2407 NR 60 TC 98 Z9 102 U1 1 U2 22 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0012-821X J9 EARTH PLANET SC LETT JI Earth Planet. Sci. Lett. PD FEB 15 PY 2003 VL 206 IS 3-4 BP 411 EP 426 DI 10.1016/S0012-821X(02)01101-9 PG 16 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 645PR UT WOS:000180988000013 ER PT J AU Cutten, DR Jarzembski, MA Srivastava, V Pueschel, RF Howard, SD McCaul, EW AF Cutten, DR Jarzembski, MA Srivastava, V Pueschel, RF Howard, SD McCaul, EW TI Boundary layer aerosol composition over Sierra Nevada Mountains using 9.11-and 10.59-mu m continuous wave lidars and modeled backscatter from size distribution data SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE aerosols; backscatter; lidar; atmospheric aerosol composition; atmospheric aerosol backscatter; remote sensing ID SAN-JOAQUIN VALLEY; OPTICAL-CONSTANTS; ATMOSPHERIC AEROSOL; CO2 LIDAR; WAVELENGTH; MICROPHYSICS; DEPENDENCE; CLIMATE; PACIFIC; SULFATE AB [1] An inversion technique has been developed to determine volume fractions of an atmospheric aerosol composed primarily of ammonium sulfate and ammonium nitrate and water combined with fixed concentration of elemental and organic carbon. It is based on measured aerosol backscatter obtained with 9.11- and 10.59-mum wavelength continuous wave CO2 lidars and modeled backscatter from aerosol size distribution data. The technique is demonstrated during a flight of the NASA DC-8 aircraft over the Sierra Nevada Mountain Range, California, on 19 September 1995. Volume fraction of each component and effective complex refractive index of the composite particle were determined assuming an internally mixed composite aerosol model. The volume fractions were also used to recompute aerosol backscatter, providing good agreement with the lidar-measured data. The robustness of the technique for determining volume fractions was extended with a comparison of calculated 2.1-mum backscatter from size distribution data with the measured lidar data converted to 2.1-mum backscatter using an earlier derived algorithm, verifying the algorithm as well as the backscatter calculations. C1 Univ Alabama, NSSTC, Huntsville, AL 35805 USA. Symtech Corp, Moffett Field, CA 94035 USA. NASA, George C Marshall Space Flight Ctr, NSSTC, Huntsville, AL 35805 USA. Univ Space Res Assoc, Huntsville, AL 35805 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Cutten, DR (reprint author), Univ Alabama, NSSTC, 320 Sparkman Dr, Huntsville, AL 35805 USA. EM cut10dr@yahoo.com; jarzembski@msfc.nasa.gov; srivastava@msfc.nasa.gov; rpueschel@mail.arc.nasa.gov; bill.mccaul@msfc.nasa.gov NR 27 TC 1 Z9 1 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 FEB 15 PY 2003 VL 108 IS D3 AR 4129 DI 10.1029/2002JD002252 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 662FH UT WOS:000181936300001 ER PT J AU Lutz, RR Mikulski, IC AF Lutz, RR Mikulski, IC TI Operational anomalies as a cause of safety-critical requirements evolution SO JOURNAL OF SYSTEMS AND SOFTWARE LA English DT Article; Proceedings Paper CT 5th IEEE International Symposium on Requirements Engineering CY AUG 27-31, 2001 CL TORONTO, CANADA SP IEEE Comp Soc, Inst Elect & Electr Engineers DE operational anomaly; requirements evolution; software safety; spacecraft; maintenance AB This paper reports the results of a small study of requirements changes to the onboard software of seven spacecraft subsequent to launch. Only those requirement changes that resulted from operational (i.e., post-launch) anomalies were of interest here, since the goal was to better understand the relationship between critical anomalies during operations and how safety-critical requirements evolve. The results of the study were surprising in that anomaly-driven requirements changes during operations were rarely due to previous requirements having been incorrect. Instead, changes involved new requirements either (1) for the software to handle rare but high-consequence events or (2) for the software itself to compensate for hardware failures or limitations. The prevalence of new requirements as a result of post-launch anomalies suggests a need for increased requirements-engineering support of maintenance activities in these systems. The results also confirm both the difficulty and the benefits of pursuing requirements completeness, especially in terms of fault tolerance, during development of critical systems. (C) 2002 Elsevier Science Inc. All rights reserved. C1 Iowa State Univ, Jet Prop Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Comp Sci, Ames, IA 50011 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Iowa State Univ, Jet Prop Lab, 226 Atanasoff Hall, Ames, IA 50011 USA. EM rlutz@cs.iastate.edu; ines.c.mikul-ski@jpl.nasa.gov NR 15 TC 15 Z9 17 U1 0 U2 1 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 FEB 15 PY 2003 VL 65 IS 2 BP 155 EP 161 DI 10.1016/S0164-1212(02)00057-2 PG 7 WC Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA 693MC UT WOS:000183720500006 ER PT J AU Bansal, NP AF Bansal, NP TI Celsian formation in fiber-reinforced barium aluminosilicate glass-ceramic matrix composites SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article DE celsian; hexacelsian; composite; X-ray diffraction ID KINETICS AB Hot pressing of barium aluminosilcate (BAS) glass or its composites reinforced with large diameter Textron chemical vapor deposited (CVD) silicon carbide SCS-6 monofilaments or small diameter multifilament Nicalon or Hi-Nicalon fibers resulted in the crystallization of both hexacelsian and monoclinic celsian phases. Effects of additions of monoclinic celsian seeds and strontium aluminosilicate (SAS) glass on crystal phase formation during hot pressing has been investigated. On doping BAS with 5 wt.% monoclinic celsian seeds or 10 wt.% SAS, only the celsian phase was formed in hot pressed monolithic specimens. However, in fiber-reinforced composites hot pressed under similar conditions, a small concentration of hexacelsian was still present as hexacelsian nucleates preferentially on surfaces and the presence of fibers provides a large surface area. When the additive concentration was increased to 10 wt.% celsian seeds or 20 wt.% SAS, celsian was the only phase detected from X-ray diffraction, with complete elimination of hexacelsian, in the hot pressed composites reinforced with large or small diameter SiC fibers. (C) 2002 Elsevier Science B.V. All rights reserved. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Bansal, NP (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 12 TC 23 Z9 29 U1 0 U2 6 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD FEB 15 PY 2003 VL 342 IS 1-2 BP 23 EP 27 AR PII S0921-5093(02)00313-1 DI 10.1016/S0921-5093(02)00313-1 PG 5 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 621BP UT WOS:000179568900003 ER PT J AU Adessi, C Walch, S Anantram, MP AF Adessi, C Walch, S Anantram, MP TI Environment and structure influence on DNA conduction SO PHYSICAL REVIEW B LA English DT Article ID ELECTRON-TRANSFER; CARBON NANOTUBES; TRANSPORT; MOLECULES; BASES AB Results for transmission through the poly{G} DNA molecule are presented. We show that (i) periodically arranged sodium counterions in close proximity to dry DNA give rise to a conduction channel, and aperiodicity in the counterion sequence can lead to a significant reduction in conduction, (ii) modification of the rise of B-DNA induces a change in the width of the transmission window, and (iii) specifically designed sequences are predicted to show intrinsic resonant tunneling behavior. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Adessi, C (reprint author), NASA, Ames Res Ctr, Mail Stop N229-1, Moffett Field, CA 94035 USA. NR 27 TC 61 Z9 62 U1 0 U2 6 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 2003 VL 67 IS 8 AR 081405 DI 10.1103/PhysRevB.67.081405 PG 4 WC Physics, Condensed Matter SC Physics GA 654WN UT WOS:000181520100012 ER PT J AU Ziemke, JR Chandra, S AF Ziemke, JR Chandra, S TI La Nina and El Nino-induced variabilities of ozone in the tropical lower atmosphere during 1970-2001 SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article DE El Nino; La Nina; troposphere; ozone; TOMS; BUV ID GROUND-BASED OBSERVATIONS; TROPOSPHERIC OZONE; STRATOSPHERIC OZONE; COLUMN OZONE; TOMS AB [1] This study provides the first evidence from several decades of satellite measurements that both La Nina and El Nino events have a comparable and dramatic impact in altering the interannual variability and distribution of tropospheric ozone in the tropics. Measurements of tropospheric ozone were combined from several total ozone mapping spectrometer (TOMS) and backscatter ultraviolet (BUV) satellite instruments to establish long time series in the tropics extending from April 1970 through December 2001. The changes in tropospheric column ozone (TCO) for both La Nina and El Nino are sizeable when compared to local values which average from less than 15 Dobson Units (DU) up to 25 DU over the year. It is suggested that interannual changes in TCO from combined La Nina and El Nino are the dominant source of decadal variability in the tropics. C1 Univ Maryland Baltimore Cty, GEST Ctr, Baltimore, MD 21228 USA. NASA, Chem & Dynam Branch, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Ziemke, JR (reprint author), Univ Maryland Baltimore Cty, GEST Ctr, Baltimore, MD 21228 USA. EM ziemke@chescat.gsfc.nasa.gov NR 16 TC 38 Z9 38 U1 1 U2 6 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 FEB 14 PY 2003 VL 30 IS 3 AR 1142 DI 10.1029/2002GL016387 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 662EY UT WOS:000181935100004 ER PT J AU Yu, HB Dickinson, RE Chin, M Kaufman, YJ Holben, BN Geogdzhayev, IV Mishchenko, MI AF Yu, HB Dickinson, RE Chin, M Kaufman, YJ Holben, BN Geogdzhayev, IV Mishchenko, MI TI Annual cycle of global distributions of aerosol optical depth from integration of MODIS retrievals and GOCART model simulations SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SUN-PHOTOMETER MEASUREMENTS; TROPOSPHERIC AEROSOLS; ANTHROPOGENIC AEROSOLS; ULTRAVIOLET-RADIATION; TRANSPORT MODEL; AIR-POLLUTION; ASSIMILATION; SATELLITE; CLIMATE; AERONET AB [1] The Moderate-Resolution Imaging Spectroradiometer (MODIS) instrument onboard the Earth Observing System (EOS) satellites provides an unprecedented opportunity to study aerosols from space with high accuracy and on a nearly global scale. However, difficulty with highly reflective arid and snow-covered lands introduces significant gaps in global or regional coverage that must be filled by some other means. This study provides a complete global coverage of an annual cycle of aerosol optical depth by combining the MODIS retrievals and Georgia Tech/Goddard Global Ozone Chemistry Aerosol Radiation and Transport (GOCART) simulations weighted with the uncertainties in each product. The assimilated aerosol optical depths over land are better correlated with the ground-based Aerosol Robotic Network (AERONET) measurements than are either the MODIS retrievals or the GOCART simulations alone. The gaps in the MODIS retrievals are filled with values that are generally consistent with the AERONET aerosol climatology. The assimilated aerosol optical depths are in good agreement with the Advanced Very High Resolution Radiometer (AVHRR) aerosol climatology over the Atlantic and North Indian Oceans. In spring, large discrepancies between the MODIS retrievals in 2001 and the AVHRR climatology over the North Pacific are likely a result of extremely active transcontinental transport of Asian dust/pollutants to North America in the year 2001. Large model-satellite differences in the South Pacific and South Indian Oceans may be attributable to missing or underestimated sources in the model and/or cloud, whitecap, and glint contamination in satellite retrievals. C1 Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. NASA, Atmospheres Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, Biospher Sci Branch, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Yu, HB (reprint author), Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. EM yu@breeze.eas.gatech.edu RI Yu, Hongbin/C-6485-2008; Chin, Mian/J-8354-2012; Mishchenko, Michael/D-4426-2012 OI Yu, Hongbin/0000-0003-4706-1575; NR 60 TC 86 Z9 87 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 FEB 14 PY 2003 VL 108 IS D3 AR 4128 DI 10.1029/2002JD002717 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 662FG UT WOS:000181936200002 ER PT J AU Merka, J Szabo, A Narock, TW King, JH Paularena, KI Richardson, JD AF Merka, J Szabo, A Narock, TW King, JH Paularena, KI Richardson, JD TI A comparison of IMP 8 observed bow shock positions with model predictions SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE terrestrial bow shock; models; IMP 8 observations ID MAGNETIC-FIELD ORIENTATION; SOLAR-WIND CONTROL; LOW MACH NUMBERS; STANDOFF DISTANCE; MHD THEORY; UNUSUAL LOCATIONS; POLYTROPIC INDEX; MAGNETOPAUSE; SHAPE; MAGNETOSHEATH AB [1] Over 12 years of IMP 8, data was searched for observed bow shock crossings. Out of the total 4562 crossings found, we used the 2293 unambiguous bow shocks for which upstream interplanetary magnetic field and solar wind parameters were available to study selected bow shock models under normal and unusual solar wind conditions. The chosen models were F79, NS91, FR94, FR94c, CL95, and P95 [Formisano, 1979; Nemecek and Safrankova', 1991; Farris and Russell, 1994; Cairns and Lyon, 1995; Peredo et al., 1995]. This statistical study investigates these models' reliability not only for average solar wind plasma and interplanetary magnetic field (IMF) conditions but also for unusual conditions and as a result points out some deficiencies of these models. Statistically, the predictions of F79 and the phenomenological and MHD models FR94, FR94c, and CL95 are the most accurate, with F79 giving a slightly better result. The P95 model predicts standoff distances which are too large by similar to20%. For large values of the IMF and its components, all models except NS91 underestimate the bow shock distance. Furthermore, the models underestimate the bow shock distance when the upstream Mach numbers are low (]5). The models also do not properly reflect changes in the relative orientation of the IMF and solar wind velocity vectors. An independent evaluation of the dawn and dusk sectors suggests an asymmetry in the bow shock shape and/or a different reaction of the flanks to solar wind deviations from a radial flow. Taking the upstream parameters from a distant solar wind monitor (the Wind spacecraft) resulted in the models predicting the shock farther away from the Earth, which is likely a result of the spacecraft separation perpendicular to the solar wind flow, or of calibrational differences of the plasma density measurements by the spacecraft. C1 NASA, Extraterr Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. L3 Commun Analyt Corp, Vienna, VA USA. NASA, Natl Space Sci Data Ctr, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. MIT, Ctr Space Res, Cambridge, MA 02139 USA. RP Merka, J (reprint author), NASA, Extraterr Phys Lab, Goddard Space Flight Ctr, Code 696, Greenbelt, MD 20771 USA. NR 46 TC 44 Z9 44 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 FEB 14 PY 2003 VL 108 IS A2 AR 1077 DI 10.1029/2002JA009384 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 662EH UT WOS:000181933600001 ER PT J AU Haywood, J Francis, P Dubovik, O Glew, M Holben, B AF Haywood, J Francis, P Dubovik, O Glew, M Holben, B TI Comparison of aerosol size distributions, radiative properties, and optical depths determined by aircraft observations and Sun photometers during SAFARI 2000 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE atmospheric aerosol; biomass burning; SAFARI 2000; Sun photometers; aerosol optical depth ID SKY RADIANCE MEASUREMENTS; SAHARAN DUST; AERONET; ABSORPTION; ALGORITHMS; PARTICLES; RETRIEVAL; SULFATE; NETWORK; TARFOX AB [1] The Meteorological Office C-130 aircraft performed a dedicated flight over the Etosha Pan surface-based Aerosol Robotic Network (AERONET) Sun photometer site on 13 September 2000 during the Southern African Aerosol Regional Science Initiative (SAFARI 2000) intensive measurement campaign. Aerosol optical depths at different wavelengths, tau(aerlambda), are derived from in situ measurements of the scattering and absorption coefficients and from various radiometric measurements and compared to those derived from the Sun photometer site. The estimates of tau(aerlambda) from the various measurements are shown to be in good agreement. The exception to this is when tau(aerlambda) is derived from the Passive Cavity Aerosol Spectrometer Probe (PCASP), as this method is shown to be extremely sensitive to the pitch angle of the aircraft; therefore, tau(aerlambda) differs for profile ascents and profile descents. However, the aerosol size distribution measured by the PCASP and derived from the AERONET site are in excellent agreement over the 0.05-1.0 mum radius range, which contains the majority of the optically active particles. C-130-derived refractive indices and single scattering albedos are also shown to be in excellent agreement with those derived from the AERONET site. The consistency between in situ and remotely sensed data suggests that, for aerosol well mixed in the vertical, data from AERONET may be used with confidence in validating satellite measurements and modeling studies of the radiative properties and effects of aerosols. C1 Meteorol Off, Bracknell RB12 2SZ, Berks, England. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Haywood, J (reprint author), Meteorol Off, Bracknell RB12 2SZ, Berks, England. EM jim.haywood@metoffice.com; pete.francis@metoffice.com; dubovik@aeronet.gsfc.nasa.gov; martin.glew@metoffice.com; brent@aeronet.gsfc.nasa.gov RI Dubovik, Oleg/A-8235-2009; Francis, Peter/H-9352-2013 OI Dubovik, Oleg/0000-0003-3482-6460; Francis, Peter/0000-0002-5869-803X NR 27 TC 75 Z9 77 U1 0 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD FEB 13 PY 2003 VL 108 IS D13 AR 8471 DI 10.1029/2002JD002250 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 662GA UT WOS:000181937900002 ER PT J AU Okkonen, SR Weingartner, TJ Danielson, SL Musgrave, DL Schmidt, GM AF Okkonen, SR Weingartner, TJ Danielson, SL Musgrave, DL Schmidt, GM TI Satellite and hydrographic observations of eddy-induced shelf-slope exchange in the northwestern Gulf of Alaska SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article DE eddies; shelf-slope exchange; hydrography; altimeter; Gulf of Alaska ID NORTHEAST PACIFIC-OCEAN; MIDDLE ATLANTIC BIGHT; WARM-CORE RING; STREAM; CIRCULATION; MODEL AB [1] Satellite and hydrographic observations of oceanographic conditions in the northwestern Gulf of Alaska indicate that anticyclonic eddies propagating adjacent to the continental shelf alter the structure of the shelf break front and, in doing so, influence the shelf-slope exchange of biota and water mass properties. Eddies typically form in the northern Gulf of Alaska during fall and winter and propagate southwestward within an 200 km wide corridor along and above the continental slope. Eddy activity within this corridor diminishes in the downstream direction. The trajectories of faster propagating (>4 km/day) eddies tend to lie closer to the shelf break than do the trajectories of slower propagating (1.5 km/day) eddies. The interaction between azimuthal eddy currents and the shelf break frontal jet (1) establishes an upwelling zone, associated with the leading flank of the eddy, that strengthens cross-slope gradients, (2) weakens cross-slope gradients and promotes shelf-slope exchange where the eddy is adjacent to the shelf, and (3) reestablishes a weak upwelling zone associated with the trailing flank of the eddy. C1 Univ Alaska, Inst Marine Sci, Fairbanks, AK 99775 USA. NASA, SAIC, SeaWiFS Project, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Okkonen, SR (reprint author), Univ Alaska, Inst Marine Sci, Fairbanks, AK 99775 USA. NR 24 TC 70 Z9 71 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-OCEANS JI J. Geophys. Res.-Oceans PD FEB 13 PY 2003 VL 108 IS C2 AR 3033 DI 10.1029/2002JC001342 PG 10 WC Oceanography SC Oceanography GA 662GN UT WOS:000181939100002 ER PT J AU Werder, T Walther, JH Jaffe, RL Halicioglu, T Koumoutsakos, P AF Werder, T Walther, JH Jaffe, RL Halicioglu, T Koumoutsakos, P TI On the water-carbon interaction for use in molecular dynamics simulations of graphite and carbon nanotubes SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID CLUSTER-SURFACE COLLISIONS; LIQUID WATER; VIBRATIONAL-SPECTRA; SUPERCRITICAL WATER; POTENTIAL FUNCTIONS; CONTACT ANGLES; NUCLEIC-ACIDS; MODEL; PROTEINS; FILMS AB A systematic molecular dynamics study shows that the contact angle of a water droplet on graphite changes significantly as a function of the water-carbon interaction energy. Together with the observation that a linear relationship can be established between the contact angle and the water monomer binding energy on graphite, a new route to calibrate interaction potential parameters is presented. Through a variation of the droplet size in the range from 1000 to 17 500 water molecules, we determine the line tension to be positive and on the order of 2x10(-10) J/m. To recover a macroscopic contact angle of 86degrees, a water monomer binding energy of -6.33 kJ mol(-1) is required, which is obtained by applying a carbon-oxygen Lennard-Jones potential with the parameters epsilon(CO)=0.392 kJ mol(-1) and sigma(CO)=3.19 Angstrom. For this new water-carbon interaction potential, we present density profiles and hydrogen bond distributions for a water droplet on graphite. C1 Swiss Fed Inst Technol, Inst Computat Sci, CH-8092 Zurich, Switzerland. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Eloret Corp, Sunnyvale, CA 94086 USA. RP Werder, T (reprint author), Swiss Fed Inst Technol, Inst Computat Sci, CH-8092 Zurich, Switzerland. RI Koumoutsakos, Petros/A-2846-2008; Walther, Jens/D-9549-2015 OI Koumoutsakos, Petros/0000-0001-8337-2122; Walther, Jens/0000-0001-8100-9178 NR 56 TC 607 Z9 616 U1 14 U2 235 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1520-6106 J9 J PHYS CHEM B JI J. Phys. Chem. B PD FEB 13 PY 2003 VL 107 IS 6 BP 1345 EP 1352 DI 10.1021/jp0268112 PG 8 WC Chemistry, Physical SC Chemistry GA 672QV UT WOS:000182533600009 ER PT J AU Lin, II Liu, WT Wu, CC Chiang, JCH Sui, CH AF Lin, II Liu, WT Wu, CC Chiang, JCH Sui, CH TI Satellite observations of modulation of surface winds by typhoon-induced upper ocean cooling SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ATMOSPHERIC BOUNDARY-LAYER; APERTURE RADAR IMAGERY; SEA-SURFACE; GULF-STREAM; TEMPERATURE; HURRICANE; WAKE AB [1] Two remote sensing data sets, the Tropical Rainfall Measurement Mission Sea Surface Temperature (SST) and the NASA QuikSCAT ocean surface wind vectors, are analysed to study ocean-atmosphere interactions in cold SST regions formed in the trail of two typhoon events. Anomalously cold SST patches up to 6degreesC below the surrounding warm tropical ocean SST are found along the trail of typhoon tracks as cold, deep waters are entrained up to the mixed layer due to typhoon forcing. In both typhoon events, significant and systematic weakening of surface wind speed is found over cold SST patches relative to surface wind speed in surrounding regions. The wind speed anomalies disappear as the patches recover to the level of the surrounding SST. The results are consistent with the mechanism proposed by Wallace et al. that surface winds are modulated by SST via stability. As wind within the well-mixed boundary layer moves over the cold patch, boundary layer stability increases, vertical mixing is suppressed, and the vertical wind shear increases; reduction in surface wind speed is caused. In particular, our result shows that this mechanism can act on relatively small spatial (approximate to 100 km) and short (approximate to 1 day) time scales. C1 Natl Ctr Ocean Res, Taipei 10617, Taiwan. NASA, Jet Prop Lab, Pasadena, CA 91109 USA. Natl Taiwan Univ, Dept Atmospher Sci, Taipei, Taiwan. Univ Washington, Joint Inst Study Atmosphere & Ocean, Seattle, WA 98195 USA. Univ Calif Berkeley, Dept Geog, Berkeley, CA 94720 USA. Natl Cent Univ, Inst Hydrol Sci, Taipei, Taiwan. RP Lin, II (reprint author), Natl Ctr Ocean Res, POB 23-13, Taipei 10617, Taiwan. RI Chiang, John/A-9421-2010; Lin, I-I/J-4695-2013; OI Lin, I-I/0000-0002-8364-8106; Wu, Chun-Chieh/0000-0002-3612-4537 NR 18 TC 71 Z9 83 U1 1 U2 9 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 FEB 12 PY 2003 VL 30 IS 3 AR 1131 DI 10.1029/2002GL015674 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 662EV UT WOS:000181934700001 ER PT J AU Pi, XQ Wang, CM Hajj, GA Rosen, G Wilson, BD Bailey, GJ AF Pi, XQ Wang, CM Hajj, GA Rosen, G Wilson, BD Bailey, GJ TI Estimation of E x B drift using a global assimilative ionospheric model: An observation system simulation experiment SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE assimilative ionospheric modeling; ionospheric data assimilation; remote sensing of the ionosphere using GPS; observation system simulation experiments ID GENERAL-CIRCULATION MODEL; F-REGION; LOWER ATMOSPHERE; THERMOSPHERE; MIDDLE AB [1] A global assimilative ionospheric model (GAIM) has been developed to improve the modeling of ionospheric weather. GAIM adopts a fixed three-dimensional Eulerian grid following a geomagnetic dipole configuration. A four-dimensional variational approach (4DVAR) with the adjoint technique is presented, which attempts to minimize the difference between modeled and measured line-of-sight total electron content (TEC) using nonlinear least squares minimization. The minimization is achieved by solving for corrections to the initial (climatological) model drivers so that the density state becomes consistent with the observations. The 4DVAR approach is exercised with GAIM in an observation system simulation experiment (OSSE) conducted for estimating the weather behavior of E x B drift at low latitudes. The OSSE takes the constellation of global positioning system (GPS) satellites and an existing global GPS receiver network as the observation system. The effectiveness of the 4DVAR technique with such an observation system is assessed in the experiment, which indicates that one can solve for the low-latitude E x B drift and improve the density modeling using ground-based, integrated line-of-sight (TEC) measurements from a relatively small number of stations. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ So Calif, Dept Math, Los Angeles, CA 90089 USA. Univ Sheffield, Dept Math Appl, Sheffield S3 7RH, S Yorkshire, England. RP Pi, XQ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 28 TC 45 Z9 47 U1 1 U2 4 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 FEB 12 PY 2003 VL 108 IS A2 AR 1075 DI 10.1029/2001JA009235 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 662ED UT WOS:000181933200001 ER PT J AU Ali, AH Zlotnicki, V AF Ali, AH Zlotnicki, V TI Quality of wind stress fields measured by the skill of a barotropic ocean model: Importance of stability of the Marine Atmospheric Boundary Layer SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID HEAT-FLUX; SEA; PARAMETERIZATION; SENSITIVITY AB [1] The stability of the Marine Atmospheric Boundary Layer (MABL) plays an important role in the air-sea exchange of momentum. Hence MABL's stability has an impact on the performance of numerical ocean models, which are driven by wind stress (along with other forcings). Here we investigate the effect of three wind stress parameterizations on the ability of a barotropic model to fit sea-level measurements from the US-French satellite TOPEX/POSEIDON (TP). We show that the wind stress parameterization that takes into account the stability of MABL enhances the model's skill to fit the TP data. Because the ocean shows a barotropic response primarily in high latitudes, the model's gain in skill is also in the high latitudes, where the probability of the MABL being unstable is in the 50% to 70% range. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ali, AH (reprint author), CALTECH, Jet Prop Lab, MS 300-323, Pasadena, CA 91109 USA. NR 15 TC 18 Z9 17 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 FEB 11 PY 2003 VL 30 IS 3 AR 1129 DI 10.1029/2002GL016058 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 662ER UT WOS:000181934400001 ER PT J AU Bell, TL Kundu, PK AF Bell, TL Kundu, PK TI Comparing satellite rainfall estimates with rain gauge data: Optimal strategies suggested by a spectral model SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE validation; precipitation; remote sensing; stochastic; space-time ID PRECIPITATION CLIMATOLOGY PROJECT; NUMERICAL-SIMULATION; GROUND VALIDATION; STOCHASTIC-MODEL; TOGA COARE; ERROR; NETWORKS; DESIGNS; SPACE; RADAR AB [1] The statistical problem of comparing rain gauge measurements to satellite rain-rate estimates over an area surrounding the gauge(s) is examined using a model of rainfall variability developed for studies of sampling error in averages of satellite data. The model is able to capture a number of important aspects of the space-time spectrum of rain-rate variability, including the interdependence of time and space scales of variability. Four parameters must be specified in the model. Sets of parameters have been obtained that fit the statistics of radar-derived rain rates over the eastern tropical Atlantic (from GATE) and the western tropical Pacific (from TOGA COARE). The model predicts that there is an optimal averaging time for gauge data when gauge averages are compared to average satellite rain-rates for a specified area around the gauge. The optimal averaging time ranges from minutes to days as the diameter of the area around the gauge is extended from 2 km to 200 km. The optimal averaging time shrinks as more gauges are added to the area viewed by the satellite, but the model suggests that even over fairly dense gauge networks it is necessary to compare averages of several hundred satellite overflights in order to bring the comparison error down to the 10% level. The possibility that comparisons of gauge data with satellite averages might be improved by weighting the gauge data differently depending on how close the gauge data are in time to the satellite overflights is investigated, and it is found that in some cases the variance of the comparison error can be reduced by a factor of two by using optimal time-dependent weighting. C1 NASA, Atmospheres Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. RP Bell, TL (reprint author), NASA, Atmospheres Lab, Goddard Space Flight Ctr, Mail Code 913, Greenbelt, MD 20771 USA. EM bell@climate.gsfc.nasa.gov; kundu@climate.gsfc.nasa.gov RI Bell, Thomas/G-5425-2012; Kundu, Prasun/C-7212-2013 OI Kundu, Prasun/0000-0002-2284-9852 NR 46 TC 41 Z9 41 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 FEB 11 PY 2003 VL 108 IS D3 AR 4121 DI 10.1029/2002JD002641 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 662FD UT WOS:000181935900004 ER PT J AU Singh, N Khazanov, G AF Singh, N Khazanov, G TI Double layers in expanding plasmas and their relevance to the auroral plasma processes SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID ELECTRIC-FIELDS; WAVES; DISTRIBUTIONS; SIMULATION AB [1] When a dense plasma consisting of a cold and a sufficiently warm electron population expands, a rarefaction shock forms [Bezzerides et al., 1978]. In the expansion of the polar wind in the magnetosphere, it has been previously shown that when a sufficiently warm electron population also exists, in addition to the usual cold ionospheric one, a discontinuity forms in the electrostatic potential distribution along the magnetic field lines [Barakat and Schunk, 1984]. Despite the lack of spatial resolution and the assumption of quasi-neutrality in the polar wind models, such discontinuities have been called double layers (DLs). Recently similar discontinuities have been invoked to partly explain the auroral acceleration of electrons and ions in the upward current region [Ergun et al., 2000]. By means of one-dimensional Vlasov simulations of expanding plasmas, for the first time we make here the connection between (1) the rarefaction shocks, (2) the discontinuities in the potential distributions, and (3) DLs. We show that when plasmas expand from opposite directions into a deep density cavity with a potential drop across it and when the plasma on the high-potential side contains hot and cold electron populations, the temporal evolution of the potential and the plasma distribution generates evolving multiple double layers with an extended density cavity between them. One of the DLs is the rarefaction-shock (RFS) and it forms by the reflections of the cold electrons coming from the high-potential side; it supports a part of the potential drop approximately determined by the hot electron temperature. The other DLs evolve from charge separations arising either from reflection of ions coming from the low-potential side or stemming from plasma instabilities; they support the rest of the potential drop. The instabilities forming these additional double layers involve electron-ion (e-i) Buneman or ion-ion (i-i) two-stream interactions. The electron-electron two-stream interactions on the high-potential side of the RFS generate electron-acoustic waves, which evolve into electron phase-space holes. The ion population originating from the low-potential side and trapped by the RFS is energized by the e-i and i-i instabilities and it eventually precipitates into the high-potential plasma along with an electron beam. Applications of these findings to the auroral plasma physics are discussed. C1 NASA, George C Marshall Space Flight Ctr, NSSTC, Huntsville, AL 35812 USA. RP Singh, N (reprint author), NASA, George C Marshall Space Flight Ctr, NSSTC, Mail Code SD50, Huntsville, AL 35812 USA. NR 33 TC 20 Z9 20 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD FEB 11 PY 2003 VL 108 IS A4 AR 8007 DI 10.1029/2002JA009436 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 662EK UT WOS:000181933800001 ER PT J AU Ling, JC Wheaton, WA AF Ling, JC Wheaton, WA TI BATSE soft gamma-ray observations of GRO J0422+32 SO ASTROPHYSICAL JOURNAL LA English DT Article DE black hole physics; gamma rays : observations ID BLACK-HOLE CANDIDATE; TRANSIENT SOURCE EXPERIMENT; CYGNUS X-1; SPECTRAL VARIABILITY; NEUTRON-STAR; MEV EMISSION; NOVA PERSEI; COMPTONIZATION; QUIESCENCE; STATES AB We report results of a comprehensive study of the soft gamma-ray (30 keV to 1.7 MeV) emission of GRO J0422+32 during its first known outburst in 1992. These results were derived from the BATSE earth-occultation database with the JPL data analysis package, EBOP (Enhanced BATSE Occultation Package). Results presented here focus primarily on the long-term temporal and spectral variability of the source emission associated with the outburst, which complement those reported earlier by BATSE, OSSE, COMPTEL, and SIGMA. The light curves with 1 day resolution in six broad energy bands (e. g., 35-100, 100-200, 200-300, 300-400, 400-700, and 700-1000 keV) show that the high-energy flux (>200 keV) led the low-energy flux (<200 keV) by similar to 5 days in reaching the primary peak, but lagged the latter by similar to 7 days in starting the declining phase. We confirm the "secondary maximum" of the low-energy (<200 keV) flux at similar toTJD 8970-8981, similar to120 days after the first maximum, reported earlier by the BATSE team. Our data show that the secondary maximum was also prominent in the 200-300 keV band, but became less pronounced at higher energies. During this 200 day period, the spectrum evolved from a power law with photon index of 1.75 on TJD 8839, to a shape that can be described by a Comptonized model or an exponential power law below 300 keV, with a variable power-law tail above 300 keV. The spectrum remained roughly in this two-component shape until around November 9 ( TJD 8935), when the 35-429 keV luminosity dropped to below similar to20% of its peak value observed on TJD 8848. It then returned to the initial power-law shape with an index of similar to2 and stayed in this shape until the end of the period. The correlation of the two spectral shapes (e.g., Compton/power law tail vs. power law) with the high and low luminosities of the soft gamma-ray emission is strongly reminiscent of that seen in Cyg X-1, suggesting that similar processes are at work in both systems. We also observed four separate episodes of high-energy (400-1000 keV) emission during the first 84 days of the event. We interpret these results in terms of the advection-dominated accretion flow (ADAF) model with possibly a "jetlike" region that persistently produced the nonthermal power-law gamma-rays observed throughout the event. C1 CALTECH, Jet Prop Lab 169 327, Pasadena, CA 91109 USA. CALTECH, Ctr Infrared Proc & Anal, Pasadena, CA 91125 USA. RP Ling, JC (reprint author), CALTECH, Jet Prop Lab 169 327, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM james.c.ling@jpl.nasa.gov; waw@ipac.caltech.edu NR 60 TC 13 Z9 13 U1 0 U2 0 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 FEB 10 PY 2003 VL 584 IS 1 BP 399 EP 413 DI 10.1086/345602 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 640UH UT WOS:000180706000029 ER PT J AU Drake, JJ Wagner, RM Starrfield, S Butt, Y Krautter, J Bond, HE Della Valle, M Gehrz, RD Woodward, CE Evans, A Orio, M Hauschildt, P Hernanz, M Mukai, K Truran, JW AF Drake, JJ Wagner, RM Starrfield, S Butt, Y Krautter, J Bond, HE Della Valle, M Gehrz, RD Woodward, CE Evans, A Orio, M Hauschildt, P Hernanz, M Mukai, K Truran, JW TI The extraordinary X-ray light curve of the classical nova V1494 Aquilae (1999 No. 2) in outburst: The discovery of pulsations and a burst SO ASTROPHYSICAL JOURNAL LA English DT Article DE novae; cataclysmic variables; stars : individual (V1494 Aquilae); stars : oscillations; white dwarfs; X-rays : binaries; X-rays : bursts ID V382 VELORUM; EMISSION; ROSAT; STAR AB V1494 Aql (Nova Aql 1999 No. 2) was discovered on 1999 December 2. We obtained Chandra ACIS-I spectra on 2000 April 15 and June 7 which appear to show only emission lines. Our third observation, on August 6, showed that its spectrum had evolved to that characteristic of a Super Soft X-ray Source. We then obtained Chandra LETG+HRC-S spectra on September 28 (8 ks) and October 1 (17 ks). We analyzed the X-ray light curve of our grating observations and found both a short timescale "burst" and oscillations. Neither of these phenomena has previously been seen in the light curve of a nova in outburst. The "burst" was a factor of similar to10 rise in X-ray counts near the middle of the second observation, and which lasted about 1000 s; it exhibited at least two peaks, in addition to other structure. Our time series analysis of the combined 25 ks observation shows a peak at similar to2500 s which is present in independent analyses of both the zeroth-order image and the dispersed spectrum and is not present in similar analyses of grating data for HZ 43 and Sirius B. Further analyses of the V1494 Aql data find other periods present which implies that we are observing nonradial g(+) modes from the pulsating, rekindled white dwarf. C1 Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. Large Binocular Telescope Observ, Tucson, AZ 85721 USA. Arizona State Univ, Dept Phys & Astron, Tempe, AZ 85287 USA. Heidelberg Koenigstuhl Landessternwarte, D-69121 Heidelberg, Germany. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Univ Florence, Dipartimento Astron & Sci Spazio, I-50125 Florence, Italy. Osserv Astrofis Arcetri, I-50125 Florence, Italy. Univ Minnesota, Dept Astron, Minneapolis, MN 55455 USA. Univ Keele, Dept Phys, Keele ST5 5BG, Staffs, England. Osserv Astron Torino, I-10025 Pino Torinese, Italy. Hamburger Sternwarte, D-21029 Hamburg, Germany. CSIC, Inst Ciencias Espacio, E-08034 Barcelona, Spain. Inst Estudis Espacials Catalunya, E-08034 Barcelona, Spain. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. RP Drake, JJ (reprint author), Smithsonian Astrophys Observ, 60 Garden St, Cambridge, MA 02138 USA. RI Hernanz, Margarita/K-1770-2014; OI Hernanz, Margarita/0000-0002-8651-7910; Della Valle, Massimo/0000-0003-3142-5020 NR 26 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 FEB 10 PY 2003 VL 584 IS 1 BP 448 EP 452 DI 10.1086/345534 PN 1 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 640UH UT WOS:000180706000034 ER PT J AU Ibrahim, AI Swank, JH Parke, W AF Ibrahim, AI Swank, JH Parke, W TI New evidence of proton-cyclotron resonance in a magnetar strength field from SGR 1806-20 SO ASTROPHYSICAL JOURNAL LA English DT Article DE stars : individual (SGR 1806-20); stars : magnetic fields; stars : neutron; X-rays : bursts ID GAMMA-REPEATER SGR-1900+14; X-RAY PULSAR; NEUTRON-STARS; DISCOVERY; SPECTRA; BURST AB A great deal of evidence has recently been gathered in favor of the picture that soft gamma repeaters and anomalous X-ray pulsars are powered by ultrastrong magnetic fields (B > 10(14) G; i.e., magnetars). Nevertheless, present determination of the magnetic field in such magnetar candidates has been indirect and model-dependent. A key prediction concerning magnetars is the detection of ion-cyclotron resonance features, which would offer a decisive diagnostic of the field strength. Here we present the detection of a 5 keV absorption feature in a variety of bursts from the soft gamma repeater SGR 1806-20, confirming our initial discovery (Ibrahim et al.) and establishing the presence of the feature in the source's burst spectra. The line feature is well explained as proton-cyclotron resonance in an ultrastrong magnetic field, offering a direct measurement of SGR 1806-20's magnetic field (B approximate to 10(15) G) and clear evidence of a magnetar. Together with the source's spin-down rate, the feature also provides the first measurement of the gravitational redshift, mass, and radius of a magnetar. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. George Washington Univ, Dept Phys, Washington, DC 20006 USA. RP Ibrahim, AI (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Mail Code 662, Greenbelt, MD 20771 USA. RI Ibrahim, Alaa/A-6250-2008; Swank, Jean/F-2693-2012 OI Ibrahim, Alaa/0000-0002-8791-7270; NR 30 TC 71 Z9 73 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 FEB 10 PY 2003 VL 584 IS 1 BP L17 EP L21 DI 10.1086/345774 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 640UJ UT WOS:000180706100005 ER PT J AU Ji, JF Zhang, SN Qu, JL Li, TP AF Ji, JF Zhang, SN Qu, JL Li, TP TI Low-frequency coherence break in the soft X-ray state of GRS 1915+105 SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; stars : individual (GRS 1915+105); X-rays : binaries ID QUASI-PERIODIC OSCILLATIONS; MICROQUASAR GRS-1915+105; RXTE OBSERVATIONS; VARIABILITY; GALAXY; TRANSITIONS; DISCOVERY; LAGS AB We present results from the analysis of X-ray power density spectra and coherence when GRS 1915+105 is in soft states. We use three data sets that belong to mu, phi, and delta classes as found in the work of Belloni et al. We find that the power density spectra appear to be complex, with several features between 0.01 and 10 Hz. The coherence deviates from unity above a characteristic frequency. We discuss our results from different models. The corona size in the sphere-disk model implied by this break frequency is on the order of 10(4) GM/c(2), which is unphysical. Our results are more consistent with the prediction of the model of a planar corona sustained by magnetic flares, in which the characteristic frequency is associated with the longest timescale of an individual flare, which is about 8 s. C1 Tsing Hua Univ, Dept Engn Phys, Beijing 100084, 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. Chinese Acad Sci, Inst High Energy Phys, Lab Particle Astrophys, Beijing 100039, Peoples R China. RP Ji, JF (reprint author), Tsing Hua Univ, Dept Engn Phys, Beijing 100084, Peoples R China. NR 24 TC 4 Z9 4 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 FEB 10 PY 2003 VL 584 IS 1 BP L23 EP L26 DI 10.1086/368269 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 640UJ UT WOS:000180706100006 ER PT J AU Wahhaj, Z Koerner, DW Ressler, ME Werner, MW Backman, DE Sargent, AI AF Wahhaj, Z Koerner, DW Ressler, ME Werner, MW Backman, DE Sargent, AI TI The inner rings of beta Pictoris SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; infrared : stars; planetary systems : formation; planetary systems : protoplanetary disks; solar system : formation ID CIRCUMSTELLAR DISK; DUST DISK; GAP FORMATION; PLANETS; ASYMMETRIES; CONSTRAINTS; SIGNATURES; HR-4796A; MODELS; IMAGES AB We present Keck images of the dust disk around beta Pictoris at lambda = 17.9 mum that reveal new structure in its morphology. Within 1" (19 AU) of the star, the long axis of the dust emission is rotated by more than 10degrees with respect to that of the overall disk. This angular offset is more pronounced than the warp detected at 3."5 by the Hubble Space Telescope (HST) and is in the opposite direction. By contrast, the long axis of the emission contours similar to1."5 from the star is aligned with the HST warp. Emission peaks between 1."5 and 4" from the star hint at the presence of rings similar to those observed in the outer disk at similar to25" with the HST Space Telescope Imaging Spectrograph. A deconvolved image strongly suggests that the newly detected features arise from a system of four noncoplanar rings. Bayesian estimates based on the primary image lead to ring radii of 14 +/- 1, 28 +/- 3, 52 +/- 2, and 82 +/- 2 AU, with orbital inclinations that alternate in orientation relative to the overall disk and decrease in magnitude with increasing radius. We believe these new results make a strong case for the existence of a nascent planetary system around beta Pic. C1 Univ Penn, David Rittenhouse Lab, Philadelphia, PA 19104 USA. No Arizona Univ, Dept Phys & Astron, Flagstaff, AZ 86001 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Franklin & Marshall Coll, Dept Phys & Astron, Lancaster, PA 17604 USA. CALTECH, Div Phys Math & Astron, Pasadena, CA 91125 USA. RP Wahhaj, Z (reprint author), Univ Penn, David Rittenhouse Lab, 209 S 33rd St, Philadelphia, PA 19104 USA. NR 46 TC 73 Z9 73 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 FEB 10 PY 2003 VL 584 IS 1 BP L27 EP L31 DI 10.1086/346123 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 640UJ UT WOS:000180706100007 ER PT J AU Sjogreen, B Yee, HC AF Sjogreen, B Yee, HC TI Grid convergence of high order methods for multiscale complex unsteady viscous compressible flows SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article; Proceedings Paper CT AIAA/CFD Conference CY JUN 11-14, 2001 CL ANAHEIM, CALIFORNIA SP AIAA, CFD ID STATE NUMERICAL-SOLUTIONS; NONLINEAR DIFFERENTIAL-EQUATIONS; REACTION-CONVECTION EQUATIONS; SOURCE TERMS; DYNAMICAL-APPROACH; CONSERVATION-LAWS; SIMULATIONS; RESOLUTION; STABILITY; SUMMATION AB Grid convergence of several high order methods for the computation of rapidly developing complex unsteady viscous compressible flows with a wide range of physical scales is studied. The recently developed adaptive numerical dissipation control high order methods referred to as the ACM and wavelet filter schemes are compared with a fifth-order weighted ENO (WENO) scheme. The two 2-D compressible full Navier-Stokes models considered do not possess known analytical and experimental data. Fine grid solutions from a standard second-order TVD scheme and a MUSCL scheme with limiters are used as reference solutions. The first model is a 2-D viscous analog of a shock tube problem which involves complex shock/shear/boundary-layer interactions. The second model is a supersonic reactive flow concerning fuel break-up. The fuel mixing involves circular hydrogen bubbles in air interacting with a planar moving shock wave. Both models contain fine scale structures and are stiff in the sense that even though the unsteadiness of the flows are rapidly developing, extreme grid refinement and time step restrictions are needed to resolve all the flow scales as well as the chemical reaction scales. Our computations were all made on uniform grids, and our conclusions cannot be directly carried over to, for example, curvilinear grids. (C) 2002 American Institute of Aeronautics and Astronautics, Inc. Published by Elsevier Science B.V. All rights reserved. C1 KTH, Dept Numer Anal & Comp Sci, S-10044 Stockholm, Sweden. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Sjogreen, B (reprint author), KTH, Dept Numer Anal & Comp Sci, S-10044 Stockholm, Sweden. NR 49 TC 30 Z9 30 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 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD FEB 10 PY 2003 VL 185 IS 1 BP 1 EP 26 AR PII S0021-9991(02)00044-X DI 10.1016/S0021-9991(02)00044-X PG 26 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 679WR UT WOS:000182945400001 ER PT J AU Mouroulis, P Hartley, FT Wilson, DW White, VE Shori, A Nguyen, S Zhang, M Feldman, M AF Mouroulis, P Hartley, FT Wilson, DW White, VE Shori, A Nguyen, S Zhang, M Feldman, M TI Blazed grating fabrication through gray-scale X-ray lithography SO OPTICS EXPRESS LA English DT Article ID IMAGING SPECTROMETERS; DESIGN AB Blazed gratings have been fabricated using gray-scale X-ray lithography. The gratings have high efficiency, low parasitic light, and high groove quality. The fabrication technique and resist characterization are described. The gratings can be generated over a considerable range of distances from the X-ray mask, thus demonstrating the ability to write gratings on a substrate of effectively arbitrary shape. (C) 2003 Optical Society of America. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Louisiana State Univ, Dept Elect & Comp Engn, Baton Rouge, LA 70803 USA. RP Mouroulis, P (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 15 TC 19 Z9 19 U1 3 U2 6 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1094-4087 J9 OPT EXPRESS JI Opt. Express PD FEB 10 PY 2003 VL 11 IS 3 BP 270 EP 281 PG 12 WC Optics SC Optics GA 643WD UT WOS:000180883700011 PM 19461733 ER PT J AU Frankland, SJV Harik, VM AF Frankland, SJV Harik, VM TI Analysis of carbon nanotube pull-out from a polymer matrix SO SURFACE SCIENCE LA English DT Article DE molecular dynamics; carbon; friction; interface states ID COMPOSITES; STRENGTH; FRICTION; MODEL; LOAD AB Molecular dynamics simulations of carbon nanotube (NT) pull-out from a polymer matrix are carried out. As the NT pull-out develops, variations in the displacement and velocities of the NT are monitored. The existence of a carbon-ring-based period in NT sliding during pull-out is identified. Linear trends in the NT velocity-force relation are observed and used to estimate an effective viscosity coefficient for interfacial sliding at the NT/polymer interface. As a result, the entire process of NT pull-out is characterized by an interfacial friction model that is based on a critical pull-out force, and art analog of Newton's friction law used to describe the NT/polymer interfacial sliding. (C) 2002 Elsevier Science B.V. All rights reserved. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Harik, VM (reprint author), NASA, LaRC, Swales Aerosp, MS 186A, Hampton, VA 23681 USA. NR 18 TC 77 Z9 77 U1 0 U2 21 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD FEB 10 PY 2003 VL 525 IS 1-3 BP L103 EP L108 AR PII S0039-6028(02)02532-3 DI 10.1016/S0039-6028(02)02532-3 PG 6 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 649BW UT WOS:000181187900001 ER PT J AU Salichon, J Delouis, B Lundgren, P Giardini, D Costantini, M Rosen, P AF Salichon, J Delouis, B Lundgren, P Giardini, D Costantini, M Rosen, P TI Joint inversion of broadband teleseismic and interferometric synthetic aperture radar (InSAR) data for the slip history of the Mw=7.7, Nazca ridge (Peru) earthquake of 12 November 1996 SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID COMPLEX BODY WAVES; TURKEY EARTHQUAKE; RUPTURE HISTORY; CALIFORNIA; SUBDUCTION; LANDERS; MOTION AB [1] The slip distribution of the 12 November 1996, Mw = 7.7, Peru earthquake is determined using broadband teleseismic waveforms, a differential SAR interferogram (interferometric synthetic aperture radar [InSAR]), and a fault parametrization allowing slip and rupture velocity to vary along the rupture plane. Both data sets are inverted jointly to limit the trade-off between the space and time aspects of the rupture. The earthquake fault plane is located at the subduction interface; it strikes parallel to the trench and dips 30degreesNE. By inverting synthetic data, we show how the InSAR and teleseismic data are complementary and how the joint inversion produces a gain in the spatial and temporal resolution of the slip model, even with a SAR interferogram that covers only part of the coseismic deformation. The rupture of the 1996 Peru event initiated on the southern flank of the subducted Nazca ridge and propagated unilaterally toward the southeast (along strike) for more than 100 km at a depth between 20 and 40 km. The area of maximum slip (6-7 m) is located 50 km southeast of the hypocenter. The total seismic moment is 4.4 x 10(20) N m (our joint inversion). The source time function is approximately 60 s long and presents three major pulses of moment release. The dominant one, which occurred between 30 and 45 s, does not correspond to the area of largest slip but to the rupture of a wide zone located about 100 km away from the hypocenter where slip reaches only 2-3 m. Computed coseismic coastal uplift correlates well with the location of raised marine terraces and with the topography of the coastal cordillera, suggesting that these features may be related to the repetition of 1996-type events at the interface between the Nazca ridge and the South American plate. C1 Swiss Fed Inst Technol, Inst Geophys, CH-8093 Zurich, Switzerland. UNSA, CNRS, Nice, Antipolis, France. Jet Propuls Lab, Pasadena, CA USA. Telespazio SpA, Rome, Italy. RP Salichon, J (reprint author), Swiss Fed Inst Technol, Inst Geophys, CH-8093 Zurich, Switzerland. EM jerome@seismo.ifg.ethz.ch RI Giardini, Domenico/F-5406-2011 NR 22 TC 27 Z9 27 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 FEB 8 PY 2003 VL 108 IS B2 AR 2085 DI 10.1029/2001JB000913 PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 661PM UT WOS:000181899000002 ER PT J AU Gumbel, J Siskind, DE Witt, G Torkar, KM Friedrich, M AF Gumbel, J Siskind, DE Witt, G Torkar, KM Friedrich, M TI Influences of ice particles on the ion chemistry of the polar summer mesosphere SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Review ID ELECTRON-TEMPERATURE DEPENDENCE; INCOHERENT-SCATTER RADAR; NOCTILUCENT CLOUDS; D-REGION; CHARGED AEROSOLS; MESOPAUSE REGION; LOWER THERMOSPHERE; UPPER-ATMOSPHERE; LOWER IONOSPHERE; WATER-VAPOR AB [1] In the polar summer mesosphere, charge is distributed over a wide range of constituents closely connected to phenomena like noctilucent clouds (NLCs) and polar mesosphere summer echoes (PMSEs). In this paper, we study how the presence of ice particles influences mesospheric ion chemistry, and how this may feed back on the particle population. To this end, we present an ion-chemical model that for the first time features close coupling with cluster growth and ice particle charging. Starting out from molecular ion reactions, the H+ (H2O)(n) proton hydrate chain is described using the Thomson model and Natanson's recombination scheme. Under most mesospheric conditions, electron capture by particles is expected to enhance the lifetimes and concentrations of positive ions and clusters. This has important consequences for the total charge density and mobility in the environment of particle layers. Extending the proton hydrate chain to large cluster sizes, we also quantify the efficiency of ionic nucleation of mesospheric ice particles. While ionic nucleation is not feasible as a major mesospheric nucleation process, it can become efficient given moderate atmospheric variations as induced by gravity waves. This leads to a scenario of rapid generation of populations with many small particles in local temperature minima. We show that electron capture to existing particles can significantly enhance the ionic nucleation of new particles. In summary, there are many potential connections between ion chemistry and layered phenomena in the mesosphere that should be included in comprehensive models of NLC/PMSE. Unfortunately, uncertainties in ionic reaction rates are a persistent problem and in great need of laboratory measurements representative for cold summer mesopause conditions. C1 Univ Space Res Assoc, Washington, DC USA. USN, Res Lab, EO Hulburt Ctr Space Res, Washington, DC 20375 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Austrian Acad Sci, Space Res Inst, A-8010 Graz, Austria. Graz Tech Univ, Dept Commun & Wave Propagat, A-8010 Graz, Austria. RP Gumbel, J (reprint author), Stockholm Univ, Dept Meteorol, S-10691 Stockholm, Sweden. EM gumbel@misu.su.se; siskind@uap2.nrl.navy.mil; gwitt@misu.su.se; klaus.torkar@oeaw.ac.at; friedrich@inw.tu-graz.ac.at NR 102 TC 20 Z9 20 U1 0 U2 9 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD FEB 7 PY 2003 VL 108 IS D8 AR 8436 DI 10.1029/2002JD002413 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 661LH UT WOS:000181891700001 ER PT J AU Proffitt, MH Aikin, K Tuck, AF Margitan, JJ Webster, CR Toon, GC Elkins, JW AF Proffitt, MH Aikin, K Tuck, AF Margitan, JJ Webster, CR Toon, GC Elkins, JW TI Seasonally averaged ozone and nitrous oxide in the Northern Hemisphere lower stratosphere SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE ozone; O-3; stratosphere; tracer; isentropic ID BALLOON-BORNE OBSERVATIONS; ARCTIC POLAR VORTEX; POTENTIAL VORTICITY; MIDDLE LATITUDES; MODEL SIMULATIONS; ANTARCTIC VORTEX; ER-2 AIRCRAFT; LOSS RATES; WINTER; TRANSPORT AB [1] Northern Hemisphere ozone (O-3) measurements in the lower stratosphere made from 1989 to 1997 are presented along with simultaneous measurements of the conserved tracer nitrous oxide (N2O) to help separate O-3 changes due to photochemistry from those due to transport. This model-independent analysis represents 139 flights aboard the ER-2 aircraft and 12 profiles from balloons and uses zonal, isobaric, and isentropic seasonal averages of O-3 and N2O to examine seasonal changes in O-3 distributions. The resulting seasonal families of curves at constant latitude are somewhat intertwined, while the families of isobaric and isentropic curves are not. Although some of the isobaric curves cross, the isentropic curves are sufficiently separated to confidently estimate O-3 by specifying season, N2O, and potential temperature, then interpolating between the curves. Such estimates may be useful for testing of photochemical models with transport, and perhaps more importantly, the families of curves could serve as baseline references for estimating high latitude photochemical O-3 loss and as an indicator of O-3 recovery in the lower stratosphere. C1 NOAA, Aeron Lab, Boulder, CO 80305 USA. Univ Colorado, NOAA, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. CALTECH, Jet Prop Lab, NASA, Pasadena, CA 91109 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80305 USA. RP Proffitt, MH (reprint author), WMO, Atmospher Res & Environm Programme, Environm Div, 7 Bis Ave Paix,Case Postale 2300, CH-1211 Geneva, Switzerland. EM proffitt@wmo.ch; kaikin@al.noaa.gov; atuck@al.noaa.gov; jm@caesar.jpl.nasa.gov; Chris.R.Webster@jpl.nasa.gov; toon@mark4sun.jpl.nasa.gov; james.w.elkins@noaa.gov RI Tuck, Adrian/F-6024-2011; Aikin, Kenneth/I-1973-2013 OI Tuck, Adrian/0000-0002-2074-0538; NR 77 TC 17 Z9 17 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 FEB 7 PY 2003 VL 108 IS D3 AR 4110 DI 10.1029/2002JD002657 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 661KN UT WOS:000181889900003 ER PT J AU Schoeberl, MR Douglass, AR Zhu, ZX Pawson, S AF Schoeberl, MR Douglass, AR Zhu, ZX Pawson, S TI A comparison of the lower stratospheric age spectra derived from a general circulation model and two data assimilation systems SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE stratospheric transport; age spectrum; age-of-air; tropical isolation; assimilation models ID MIDLATITUDE LOWER STRATOSPHERE; QUASI-BIENNIAL OSCILLATION; POLAR VORTEX; TRANSPORT; AIR; TROPOSPHERE; VIEW; FORM AB [1] We use kinematic and diabatic back trajectory calculations, driven by winds from a general circulation model (GCM) and two different data assimilation systems (DAS), to compute the age spectrum at three latitudes in the lower stratosphere. The age spectra are compared to chemical transport model (CTM) calculations, and the mean ages from all of these studies are compared to observations. The age spectra computed using the GCM winds show a reasonably isolated tropics, in good agreement with observations; however, the age spectra determined from the DAS differ from the GCM spectra. For the DAS diabatic trajectory calculations there is too much exchange between the tropics and midlatitudes. The age spectrum is thus too broad, and the tropical mean age is too old as a result of mixing older midlatitude air with tropical air. Likewise, the midlatitude mean age is too young because of the in-mixing of tropical air. The DAS kinematic trajectory calculations show excessive vertical dispersion of parcels in addition to excessive exchange between the tropics and midlatitudes. Because air is moved rapidly to the troposphere from the vertical dispersion, the age spectrum is shifted toward the young side. The excessive vertical and meridional dispersion compensate in the kinematic case, giving a reasonable tropical mean age. The CTM calculation of the age spectrum using the DAS winds shows the same vertical and meridional dispersive characteristics of the kinematic trajectory calculation. These results suggest that the current DAS products will not give realistic trace gas distributions for long integrations; they also help explain why the extratropical mean ages determined in a number of previous DAS-driven CTMs are too young compared with observations. Finally, we note that trajectory-generated age spectra show significant age anomalies correlated with the seasonal cycles. These anomalies can be linked to year-to-year variations in the tropical heating rate. The anomalies are suppressed in the CTM spectra, suggesting that the CTM transport scheme is too diffusive. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Sci Applicat Int Corp, Greenbelt, MD USA. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. RP Schoeberl, MR (reprint author), NASA, Goddard Space Flight Ctr, Code 916,Bldg 33,Room E311A, Greenbelt, MD 20771 USA. EM schom@zephyr.gsfc.nasa.gov RI Douglass, Anne/D-4655-2012; Pawson, Steven/I-1865-2014 OI Pawson, Steven/0000-0003-0200-717X NR 41 TC 105 Z9 105 U1 0 U2 9 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD FEB 7 PY 2003 VL 108 IS D3 AR 4113 DI 10.1029/2002JD002652 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 661KN UT WOS:000181889900002 ER PT J AU Gary, SP Yin, L Winske, D Ofman, L Goldstein, BE Neugebauer, M AF Gary, SP Yin, L Winske, D Ofman, L Goldstein, BE Neugebauer, M TI Consequences of proton and alpha anisotropies in the solar wind: Hybrid simulations SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE solar wind; hybrid simulations; instabilities; Alfven waves ID WAVE-ION INTERACTION; ULYSSES OBSERVATIONS; TEMPERATURE ANISOTROPY; CYCLOTRON-RESONANCE; VELOCITY DISTRIBUTIONS; PLASMA PARAMETERS; KINETIC EVOLUTION; ALFVEN WAVES; HEAVY-IONS; ACCELERATION AB [1] Alfven fluctuations propagating away from the Sun in the solar corona and solar wind transfer energy via cyclotron resonances to ions of successively larger charge-to-mass ratios. This can yield T-perpendicular to/T-parallel to > 1 for each ion species, where the subscripts refer to directions relative to the background magnetic field. If these anisotropies become sufficiently large, they drive electromagnetic ion cyclotron instabilities. This paper describes two-dimensional hybrid simulations of a collisionless, homogeneous, magnetized plasma to study the consequences of scattering by enhanced field fluctuations from such instabilities. The ions in the simulations consist of majority protons and minority alpha particles with initial bi-Maxwellian velocity distributions and representative solar wind parameters including a nonzero alpha/proton relative speed. The simulations show that both helium and proton cyclotron instabilities reduce the driving anisotropy, reduce initial differences between the proton and alpha particle anisotropies, and, as a new result, usually reduce initial alpha/proton speeds. These results are somewhat different from theoretical predictions of ion scattering by interaction with outward propagating Alfven-cyclotron waves but are consistent with observations from Ulysses. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Gary, SP (reprint author), Los Alamos Natl Lab, MS D466, Los Alamos, NM 87545 USA. NR 53 TC 37 Z9 37 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 FEB 7 PY 2003 VL 108 IS A2 AR 1068 DI 10.1029/2002JA009654 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 662DW UT WOS:000181932500005 ER PT J AU Meneghini, R Bidwell, SW Rincon, R Heymsfield, GM Liao, L AF Meneghini, R Bidwell, SW Rincon, R Heymsfield, GM Liao, L TI Differential-frequency Doppler weather radar: theory and experiment SO RADIO SCIENCE LA English DT Article DE Doppler; radar; differential-frequency; rain; spaceborne radar; drop size distribution ID DROP SIZE DISTRIBUTION; EDOP RADAR; REFLECTIVITY; FEASIBILITY AB [1] To move toward spaceborne weather radars that can be deployed routinely as part of an instrument set consisting of passive and active sensors requires the development of smaller, lighter-weight radars. At the same time, the addition of a second frequency and an upgrade to Doppler capability are essential to retrieve information on the drop size distribution (DSD), vertical air motion, and storm dynamics. One approach to the problem is to use a single broadband transmitter-receiver and antenna where two narrowband frequencies are spaced apart by 7-10%. Use of Ka-band frequencies (26.5-40 GHz) provides adequate spatial resolution with a relatively small antenna. Moreover, the differential reflectivity and mean Doppler signals in this band are directly related to the median mass diameter of the snow and raindrop size distributions. We present in the paper theoretical calculations of the differential reflectivity and Doppler for several frequency pairs including those proposed for the Global Precipitation Mission (GPM) at 13.6 and 35 GHz. Measurements from a zenith-directed radar operated at 9.1 and 10 GHz are used to investigate the qualitative characteristics of the differential signals. Disdrometer data taken at the surface, just below the radar, show that the differential signals are related to characteristics of the raindrop size distribution. The stability of the DSD estimation procedure is tested using a simulation. The results indicate that reasonably stable estimates of the particle size distribution are feasible with a [31.5 GHz, 35 GHz] combination as long as a large number of independent samples are obtained. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Caelum Res Corp, Rockville, MD USA. RP Meneghini, R (reprint author), NASA, Goddard Space Flight Ctr, Code 975, Greenbelt, MD 20771 USA. EM bob@priam.gsfc.na RI Measurement, Global/C-4698-2015 NR 15 TC 4 Z9 4 U1 0 U2 0 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 FEB 7 PY 2003 VL 38 IS 3 AR 8040 DI 10.1029/2002RS002656 PG 11 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA 661RN UT WOS:000181903700003 ER PT J AU Morris, GA Rosenfield, JE Schoeberl, MR Jackman, CH AF Morris, GA Rosenfield, JE Schoeberl, MR Jackman, CH TI Potential impact of subsonic and supersonic aircraft exhaust on water vapor in the lower stratosphere assessed via a trajectory model SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE stratospheric water vapor; trajectory modeling; temperature perturbations; subsonic aircraft emissions; supersonic aircraft emissions ID EMISSIONS; SIMULATION; COMPUTATIONS; TROPOSPHERE; O-3; GCM AB [1] We employ a trajectory model to assess the impact on the stratosphere of water vapor present in the exhaust of subsonic and a proposed fleet of supersonic aircraft. Air parcels into which water vapor from aircraft exhaust has been injected are run through a 6-year simulation in the trajectory model using meteorological data from the UKMO analyses with emissions dictated by the standard 2015 emissions scenario. For the subsonic aircraft, our results suggest maximum enhancements of similar to150 ppbv just above the Northern Hemisphere tropopause and of much less than 50 ppbv in most other regions. Inserting the perturbed water vapor profiles into a radiative transfer model, but not considering the impact of additional cirrus formation resulting from emissions by subsonic aircraft, we find that the impact of subsonic water vapor emissions on the radiative balance is negligible. For the supersonic case, our results show maximum enhancements of similar to1.5 ppmv in the tropical stratosphere near 20 km. Much of the remaining stratosphere between 12 and 25 km sees enhancements of greater than 0.1 ppmv, although enhancements above 35 km are generally less than 50 ppbv, in contrast to previous 2-D and 3-D model studies. Radiative calculations based upon these projected water vapor perturbations indicate they may cause a nonnegligible impact on tropical temperature profiles. Since our trajectory model includes no chemistry and our radiative calculations use the most extreme water vapor perturbations, our results should be viewed as upper limits on the potential impacts. C1 Rice Univ, Dept Phys & Astron, Houston, TX 77251 USA. Univ Maryland Baltimore Cty, GEST Ctr, Baltimore, MD 21250 USA. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. RP Morris, GA (reprint author), Rice Univ, Dept Phys & Astron, 6100 Main St,MS-61, Houston, TX 77251 USA. EM gmorris@rice.edu RI Jackman, Charles/D-4699-2012 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 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD FEB 6 PY 2003 VL 108 IS D3 AR 4103 DI 10.1029/2002JD002614 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 661KL UT WOS:000181889700005 ER PT J AU Zhao, TXP Laszlo, I Holben, BN Pietras, C Voss, KJ AF Zhao, TXP Laszlo, I Holben, BN Pietras, C Voss, KJ TI Validation of two-channel VIRS retrievals of aerosol optical thickness over ocean and quantitative evaluation of the impact from potential subpixel cloud contamination and surface wind effect SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE aerosol retrieval; validation; remote sensing; cloud contamination ID RAINFALL MEASURING MISSION; INDIVIDUAL AVHRR CHANNELS; SPECTRAL REFLECTANCE; CONSISTENCY CHECKS; INFRARED SCANNER; QUALITY-CONTROL; SATELLITE; AERONET; INFORMATION; ALGORITHM AB [1] TRMM/CERES-VIRS Single Satellite Footprint (SSF) data and AERONET Sun/sky radiometer observations from 1998 have been combined to validate SSF aerosol optical thickness (tau) retrievals over ocean along with a quantitative evaluation of the effects of potential subpixel cloud contamination and surface wind on the satellite tau retrievals. Potential subpixel cloud contamination is verified in Visible/Infrared Scanner (VIRS) SSF aerosol retrievals and constitutes a major source of systematic and random errors of the retrieval algorithm as determined from comparisons with AERONET observations. A positive correlation between the surface wind speed (which determines the roughness of the ocean surface) and the SSF tau has been observed for large surface wind speed. The validation results imply this correlation represents the real relationship between the surface wind and the wind-driven aerosols rather than the disturbing effect of the surface reflectance associated with the rough ocean surface. After the potential subpixel cloud contamination is minimized and the effects of large surface wind are removed in the tau match-ups, the positive biases in the SSF tau (compared to AERONET tau) for mean conditions have been reduced from 0.05 to 0.02 in VIRS channel 1 (0.63 mum) and 0.05 to 0.03 in channel 2 (1.61 mum). Random errors have also been reduced from 0.09 to 0.06 at 0.63 mum, and from 0.06 to 0.05 at 1.61 mum. The validation results support the application of the SSF aerosol data in radiation and climate studies as well as supply useful guidance for the adjustment and improvement of the aerosol retrieval algorithm. C1 NOAA, Natl Environm Satellite Data & Informat Serv, Off Res & Applicat, Camp Springs, MD 20746 USA. NOAA, Cooperat Inst Res Atmosphere, Camp Springs, MD 20746 USA. NASA, Goddard Space Flight Ctr, Sci Applicat Int Corp, Greenbelt, MD 20771 USA. Univ Miami, Dept Phys, Coral Gables, FL 33124 USA. RP Zhao, TXP (reprint author), NOAA, Natl Environm Satellite Data & Informat Serv, Off Res & Applicat, E-RA1,RM 711-B,WWBG,5200 Auth Rd, Camp Springs, MD 20746 USA. EM xuepeng.zhao@noaa.gov RI Laszlo, Istvan/F-5603-2010; Voss, Kenneth /A-5328-2013 OI Laszlo, Istvan/0000-0002-5747-9708; Voss, Kenneth /0000-0002-7860-5080 NR 49 TC 7 Z9 8 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD FEB 6 PY 2003 VL 108 IS D3 AR 4106 DI 10.1029/2002JD002346 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 661KL UT WOS:000181889700002 ER PT J AU Bayes, KD Toohey, DW Friedl, RR Sander, SP AF Bayes, KD Toohey, DW Friedl, RR Sander, SP TI Measurements of quantum yields of bromine atoms in the photolysis of bromoform from 266 to 324 nm SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ATMOSPHERIC BROMINE; LOWER STRATOSPHERE; CHEMISTRY; KINETICS; CHLORINE; GASES; OZONE; BRO AB [1] The quantum yield for the formation of bromine atoms in the photolysis of bromoform, CHBr3, has been measured between 266 and 324 nm. For 303 to 306 nm the quantum yields are unity within the experimental uncertainty of the measurements. At longer wavelengths, where the bromoform cross sections decrease rapidly, an apparent trend to slightly lower quantum yields is probably the result of systematic and random errors or incorrect CHBr3 absorption cross sections. Support for a unit quantum yield for all wavelengths longer than 300 nm comes from the recent theoretical calculations of Peterson and Francisco. At 266 nm the bromine atom quantum yield is 0.76 (+/-0.03), indicating that at least one additional dissociation channel becomes important at shorter wavelengths. For modeling of the troposphere, it is recommended that a quantum yield of unity be used for wavelengths of 300 nm and longer. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Colorado, Program Atmospher & Ocean Sci, Boulder, CO 80309 USA. RP Bayes, KD (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM bayes@chem.ucla.edu RI Toohey, Darin/A-4267-2008 OI Toohey, Darin/0000-0003-2853-1068 NR 35 TC 10 Z9 10 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD FEB 5 PY 2003 VL 108 IS D3 AR 4095 DI 10.0029/2002JD002877 PG 6 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 661KE UT WOS:000181889100007 ER PT J AU Cantrell, CA Mauldin, L Zondlo, M Eisele, F Kosciuch, E Shetter, R Lefer, B Hall, S Campos, T Ridley, B Walega, J Fried, A Wert, B Flocke, F Weinheimer, A Hannigan, J Coffey, M Atlas, E Stephens, S Heikes, B Snow, J Blake, D Blake, N Katzenstein, A Lopez, J Browell, EV Dibb, J Scheuer, E Seid, G Talbot, R AF Cantrell, CA Mauldin, L Zondlo, M Eisele, F Kosciuch, E Shetter, R Lefer, B Hall, S Campos, T Ridley, B Walega, J Fried, A Wert, B Flocke, F Weinheimer, A Hannigan, J Coffey, M Atlas, E Stephens, S Heikes, B Snow, J Blake, D Blake, N Katzenstein, A Lopez, J Browell, EV Dibb, J Scheuer, E Seid, G Talbot, R TI Steady state free radical budgets and ozone photochemistry during TOPSE SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID LASER-INDUCED FLUORESCENCE; IN-SITU MEASUREMENTS; UPPER TROPOSPHERE; PHOTOSTATIONARY STATE; PEROXY-RADICALS; ATMOSPHERIC CHEMISTRY; CONVECTIVE INJECTION; HYDROGEN RADICALS; POLAR SUNRISE; PEM-TROPICS AB [1] A steady state model, constrained by a number of measured quantities, was used to derive peroxy radical levels for the conditions of the Tropospheric Ozone Production about the Spring Equinox (TOPSE) campaign. The analysis is made using data collected aboard the NCAR/NSF C-130 aircraft from February through May 2000 at latitudes from 40degrees to 85degreesN, and at altitudes from the surface to 7.6 km. HO2 +RO2 radical concentrations were measured during the experiment, which are compared with model results over the domain of the study showing good agreement on the average. Average measurement/model ratios are 1.04 (sigma = 0.73) and 0.96 (sigma = 0.52) for the MLB and HLB, respectively. Budgets of total peroxy radical levels as well as of individual free radical members were constructed, which reveal interesting differences compared to studies at lower latitudes. The midlatitude part of the study region is a significant net source of ozone, while the high latitudes constitute a small net sink leading to the hypothesis that transport from the middle latitudes can explain the observed increase in ozone in the high latitudes. Radical reservoir species concentrations are modeled and compared with the observations. For most conditions, the model does a good job of reproducing the formaldehyde observations, but the peroxide observations are significantly less than steady state for this study. Photostationary state (PSS) derived total peroxy radical levels and NO/NO2 ratios are compared with the measurements and the model; PSS-derived results are higher than observations or the steady state model at low NO concentrations. C1 Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80303 USA. Georgia Inst Technol, Atlanta, GA 30332 USA. Univ Rhode Isl, Sch Oceanog, Narragansett, RI USA. Univ Calif Irvine, Irvine, CA USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. Univ New Hampshire, Durham, NH 03824 USA. RP Cantrell, CA (reprint author), Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80303 USA. EM cantrell@ncar.ucar.edu RI Atlas, Elliot/J-8171-2015; Lefer, Barry/B-5417-2012; Zondlo, Mark/R-6173-2016 OI Lefer, Barry/0000-0001-9520-5495; Zondlo, Mark/0000-0003-2302-9554 NR 92 TC 36 Z9 36 U1 1 U2 10 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD FEB 5 PY 2003 VL 108 IS D4 AR 8361 DI 10.1029/2002JD002198 PG 22 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 661KR UT WOS:000181890200001 ER PT J AU Fridlind, AM Jacobson, MZ AF Fridlind, AM Jacobson, MZ TI Point and column aerosol radiative closure during ACE 1: Effects of particle shape and size SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE aerosols; radiation; scattering coefficient; optical depth; backscattering coefficient; nonsphericity ID MARINE BOUNDARY-LAYER; SEA-SALT PARTICLES; OPTICAL-PROPERTIES; NONSPHERICAL PARTICLES; SOUTHERN-OCEAN; INTEGRATING NEPHELOMETER; TROPOSPHERIC AEROSOLS; LIGHT-SCATTERING; MASS; CHLORIDE AB [1] We used data collected during the First Aerosol Characterization Experiment (ACE 1) to study point and column aerosol radiative closure over the remote ocean. To test point closure, total and hemispheric backscattering coefficients calculated with a Mie single-scattering model were compared with measurements made by ship and aircraft at three wavelengths (400, 550, and 700 nm). On the ship, assuming spherical particles, calculated total scattering was usually within 10% of measurements (closure obtained in >80% of the cases) but calculated backscattering was usually 15-25% lower than measurements (closure obtained in <50% of the cases). When a model for particle nonsphericity was applied to the dried sea spray, assuming the particles to be ideal cubes or irregular convex and concave crystals resulted in overestimation of backscattering. However, when nonsphericity parameters were fit to the measurements, calculated backscattering was also usually within 10% of measurements (closure obtained in >80% of the cases). On the aircraft, however, calculated scattering and backscattering were usually lower than measurements by 20-45% regardless of assumed particle shape (closure obtained in <50% of the cases), likely owing to differences in the aerosol inlet penetration efficiencies to each instrument or unidentified uncertainties in the measured number size distributions or scattering coefficients. To test column closure, aerosol extinction profiles calculated from in situ observations (below 5.5 km) and satellite observations (above 5.5 km) were vertically integrated, and the resulting aerosol optical depth was compared with measurements made on the ship during two clear-sky days at three wavelengths (500, 778, and 862 nm). Calculated spectral optical depths were usually within 25% of measurements (closure obtained at one or more wavelengths on both days), and agreement at longer wavelengths was improved when satellite measurements were spectrally scaled using in situ model results. On both days, large sea salt particles produced a spectrally neutral aerosol optical depth in the marine boundary layer whereas smaller ammonium sulfate particles contributed to greater optical depth at shorter wavelengths in the overlying upper atmosphere. C1 Stanford Univ, Dept Civil & Environm Engn, Stanford, CA 94305 USA. RP Fridlind, AM (reprint author), NASA, Ames Res Ctr, Div Earth Sci, Mail Stop 245-4, Moffett Field, CA 94035 USA. EM fridlind@ice.arc.nasa.gov; jacobson@ce.stanford.edu RI Fridlind, Ann/E-1495-2012 NR 63 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 FEB 4 PY 2003 VL 108 IS D3 AR 4094 DI 10.1029/2001JD001553 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 661KC UT WOS:000181888900003 ER PT J AU Cassell, AM McCool, GC Ng, HT Koehne, JE Chen, B Li, J Han, J Meyyappan, M AF Cassell, AM McCool, GC Ng, HT Koehne, JE Chen, B Li, J Han, J Meyyappan, M TI Carbon nanotube networks by chemical vapor deposition SO APPLIED PHYSICS LETTERS LA English DT Article ID NANOSTRUCTURES; CIRCUITS AB We have demonstrated assembly of two- and three-dimensional networks of single-walled carbon nanotubes (SWNTs) using a microsphere assembly approach. The catalyst microcapsules are made from the solution based impregnation of uniform diameter, porous polystyrene microspheres. Chemical vapor deposition on the microcapsule arrays produces highly interconnected SWNT networks. Varying the microsphere diameter and catalyst solution composition allows varying the pattern spacing, catalyst yield, and network interconnectivity. (C) 2003 American Institute of Physics. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. ELORET Corp, Sunnyvale, CA 94087 USA. RP Cassell, AM (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 17 TC 39 Z9 39 U1 1 U2 12 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 3 PY 2003 VL 82 IS 5 BP 817 EP 819 DI 10.1063/1.1543252 PG 3 WC Physics, Applied SC Physics GA 640KG UT WOS:000180687600052 ER PT J AU Roeber, D Achari, A Manavalan, P Edmunds, T Scott, DL AF Roeber, D Achari, A Manavalan, P Edmunds, T Scott, DL TI Crystallization and preliminary X-ray analysis of recombinant human acid beta-glucocerebrosidase, a treatment for Gaucher's disease SO ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY LA English DT Article ID REPLACEMENT THERAPY AB Acid beta-glucocerebrosidase (N-acylsphingosyl-1-O-beta-D-glucoside: glucohydrolase) is a lysosomal glycoprotein that catalyzes the hydrolysis of the glycolipid glucocerebroside to glucose and ceramide. Inadequate levels of this enzyme underly the pathophysiology of Gaucher's disease. Cerezyme (Genzyme Corporation, Cambridge, MA, USA) is a partially deglycosylated form of recombinant human acid beta-glucocerebrosidase that is used in the treatment of Gaucher patients. Although acid beta-glucocerebrosidase belongs to a large family of glycosidases, relatively little is known regarding its structural biology. Here, the crystallization and the initial diffraction analysis of Cerezyme are reported. The crystals are C-centered orthorhombic, with unit-cell parameters a = 285.0, b = 110.2, c = 91.7 Angstrom. A 99.9% complete data set has been collected to 2.75 Angstrom with an R-sym of 8.8%. C1 Harvard Univ, Sch Med, Massachusetts Gen Hosp, Dept Med & Orthopaed Surg, Charlestown, MA 02129 USA. Harvard Univ, Sch Med, Massachusetts Gen Hosp, Struct Biol Unit, Charlestown, MA 02129 USA. Genzyme Corp, Framingham, MA 01701 USA. NASA, George C Marshall Space Flight Ctr, Struct Biol Lab, Huntsville, AL 35812 USA. RP Scott, DL (reprint author), Harvard Univ, Sch Med, Massachusetts Gen Hosp, Dept Med & Orthopaed Surg, 149 13th St, Charlestown, MA 02129 USA. NR 18 TC 4 Z9 4 U1 0 U2 3 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 FEB PY 2003 VL 59 BP 343 EP 344 DI 10.1107/S0907444902020498 PN 2 PG 2 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Biophysics; Crystallography SC Biochemistry & Molecular Biology; Biophysics; Crystallography GA 639QZ UT WOS:000180641900017 PM 12554947 ER PT J AU Georgiadis, NJ Alexander, JID Reshotko, E AF Georgiadis, NJ Alexander, JID Reshotko, E TI Hybrid reynolds-averaged Navier-Stokes/large-Eddy simulations of supersonic turbulent mixing SO AIAA JOURNAL LA English DT Article ID LAYER AB A turbulent mixing layer formed from two supersonic streams initially separated by a splitter plate is investigated with a hybrid computational method using a Reynolds-averaged Navier-Stokes (RANS) approach for wall-bounded regions and a large-eddy simulation (LES) approach for the turbulent mixing region. Simulations of the mixing layer predict a vortex shedding originating from the splitter base and then a rapid transition to turbulence, which is in agreement with experimental observations. As a result, the potential of the hybrid method is demonstrated for flows in which a geometric feature, such as the blunt splitter plate considered here, provides the dominant unsteady feature leading to turbulence, without imposing additional inflow disturbances. Parametric studies of LES subgrid modeling settings, variations in the spanwise computational domain, and wall temperature settings in the RANS region were conducted. The subgrid model cases, using a baseline computational grid with small spanwise computational domain, overpredicted the mixing layer turbulence levels but only showed small variation in the mixing layer predictions with large changes in the model parameters. The cases examining wider spanwise domains enabled more turbulent energy to be released in the spanwise direction, which in turn reduced axial and vertical turbulence levels. Finally, prescribing the wall temperatures in the RANS regions instead of using the more traditional adiabatic wall boundary conditions further reduced turbulence levels and enabled reasonable agreement with experimental data. C1 NASA, John H Glenn Res Ctr Lewis Field, Nozzle Branch, Cleveland, OH 44135 USA. Case Western Reserve Univ, Dept Mech & Aerosp Engn, Cleveland, OH 44106 USA. RP Georgiadis, NJ (reprint author), NASA, John H Glenn Res Ctr Lewis Field, Nozzle Branch, Cleveland, OH 44135 USA. NR 28 TC 23 Z9 27 U1 0 U2 5 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD FEB PY 2003 VL 41 IS 2 BP 218 EP 229 DI 10.2514/2.1934 PG 12 WC Engineering, Aerospace SC Engineering GA 648ET UT WOS:000181137300010 ER PT J AU Danehy, PM O'Byrne, S Houwing, AFP Fox, JS Smith, DR AF Danehy, PM O'Byrne, S Houwing, AFP Fox, JS Smith, DR TI Flow-tagging velocimetry for hypersonic flows using fluorescence of nitric oxide SO AIAA JOURNAL LA English DT Article ID LASER-INDUCED FLUORESCENCE; PLANAR DOPPLER VELOCIMETRY; BOUNDARY-LAYER; GAS-FLOWS; RAYLEIGH-SCATTERING; FLAT-PLATE; VELOCITY; PRESSURE; TEMPERATURE; BODY AB We demonstrate a new variation of molecular-tagging velocimetry for hypersonic flows based on laser-induced fluorescence. A thin line of nitric-oxide molecules is excited with a laser beam and then, after a time delay, a fluorescence image of the displaced line is acquired. One component of velocity is determined from the time of flight. This method is applied to measure the velocity profile in a Mach 8.5 laminar, hypersonic boundary layer in the Australian National University's T2 free-piston shock tunnel. The single-shot velocity measurement uncertainty in the freestream was found to be 3.5%, based on 90% confidence. The method is also demonstrated in the separated flow region forward of a blunt fin attached to a flat plate in a Mach 7.4 How produced by the Australian National University's T3 free-piston shock tunnel. The measurement uncertainty in the blunt fin experiment is approximately 30%, owing mainly to low fluorescence intensities, which could be improved significantly in future experiments. This velocimetry method is applicable to very high-speed flows that have low collisional quenching of the fluorescing species. It is particularly convenient in facilities where planar laser-induced fluorescence is already being performed. C1 NASA, Langley Res Ctr, Instrumentat Syst Dev Branch, Hampton, VA 23681 USA. Australian Natl Univ, Dept Phys, Fac Sci, Canberra, ACT 0200, Australia. RP Danehy, PM (reprint author), NASA, Langley Res Ctr, Instrumentat Syst Dev Branch, Hampton, VA 23681 USA. NR 37 TC 30 Z9 32 U1 2 U2 9 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD FEB PY 2003 VL 41 IS 2 BP 263 EP 271 DI 10.2514/2.1939 PG 9 WC Engineering, Aerospace SC Engineering GA 648ET UT WOS:000181137300015 ER PT J AU Baginski, FE Schur, WW AF Baginski, FE Schur, WW TI Structural analysis of pneumatic envelopes: Variational formulation and optimization-based solution process SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT AIAA 3rd Gossamer Spacecraft Forum CY APR 22-25, 2002 CL DENVER, COLORADO SP AIAA ID HIGH-ALTITUDE BALLOONS AB Large super-light structural systems that for functional reasons require large surfaces are composed at least in part of structural membranes. The underconstrained nature of such structural membranes poses analytical challenges, but also provides design opportunities that are not commonly found in other structural systems that require the arsenal of solid-mechanics analytical tools for the assessment of design validity and performance. Overcoming some of the challenges that are posed by the underconstrained nature of such systems is an important ingredient in the development process for gossamer spacecraft. Our approach is a variational formulation of the analytical problem in conjunction with optimization techniques in the solution process. The optimization-based solution process avoids convergence problems that are encountered in the implicit solution process of finite element formulations of these underconstrained structures. To illustrate our approach, we carry out a structural analysis of a pumpkin balloon. Our formulation incorporates wrinkling of the balloon film and structural lack of fit between the skin and the tendon in the unloaded, that is, unstrained, structure. Our results on pumpkin balloons suggest the possibility of similar success if our methods are applied to other pneumatic envelopes. C1 George Washington Univ, Dept Math, Washington, DC 20052 USA. New Mexico State Univ, Lab Phys Sci, Field Engn Grp, NASA,GSFC,WFF, Wallops Isl, VA 23337 USA. RP Baginski, FE (reprint author), George Washington Univ, Dept Math, Washington, DC 20052 USA. NR 12 TC 12 Z9 12 U1 1 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD FEB PY 2003 VL 41 IS 2 BP 304 EP 311 DI 10.2514/2.1945 PG 8 WC Engineering, Aerospace SC Engineering GA 648ET UT WOS:000181137300020 ER PT J AU Lucas, RA Baum, SA Brown, TM Casertano, S Conselice, C de Mello, D Dickinson, ME Ferguson, HC Fruchter, AS Gardner, JP Gilmore, D Gonzalez-Lopezlira, RA Heyer, I Hook, RN Kaiser, ME Mack, J Makidon, R Martin, CL Mutchler, M Smith, TE Stiavelli, M Teplitz, HI Wiggs, MS Williams, RE Zurek, DR AF Lucas, RA Baum, SA Brown, TM Casertano, S Conselice, C de Mello, D Dickinson, ME Ferguson, HC Fruchter, AS Gardner, JP Gilmore, D Gonzalez-Lopezlira, RA Heyer, I Hook, RN Kaiser, ME Mack, J Makidon, R Martin, CL Mutchler, M Smith, TE Stiavelli, M Teplitz, HI Wiggs, MS Williams, RE Zurek, DR TI The Hubble Deep Field South flanking fields SO ASTRONOMICAL JOURNAL LA English DT Article DE catalogs; cosmology : observations; galaxies : evolution; galaxies : photometry; galaxies : statistics; surveys ID FAINT GALAXIES; PHOTOMETRY; COUNTS AB As part of the Hubble Deep Field South program, a set of shorter two-orbit observations were obtained of the area adjacent to the deep fields. The WFPC2 flanking fields cover a contiguous solid angle of 48 arcmin(2). Parallel observations with the STIS and NICMOS instruments produce a patchwork of additional fields with optical and near-infrared (1.6 mum) response. Deeper parallel exposures with WFPC2 and NICMOS were obtained when STIS observed the NICMOS deep field. These deeper fields are offset from the rest, and an extended low surface brightness object is visible in the deeper WFPC2 flanking field. In this data paper, which serves as an archival record of the project, we discuss the observations and data reduction and present SExtractor source catalogs and number counts derived from the data. Number counts are broadly consistent with previous surveys from both ground and space. Among other things, these flanking field observations are useful for de ning slit masks for spectroscopic follow-up over a wider area around the deep fields, for studying large-scale structure that extends beyond the deep fields, for future supernova searches, and for number counts and morphological studies, but their ultimate utility will be defined by the astronomical community. C1 Space Telescope Sci Inst, Baltimore, MD 21218 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. European So Observ, Space Telescope European Coordinating Facil, D-85748 Garching, Germany. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. RP Lucas, RA (reprint author), Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA. RI Conselice, Christopher/B-4348-2013; OI Conselice, Christopher/0000-0003-1949-7638 NR 26 TC 9 Z9 9 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD FEB PY 2003 VL 125 IS 2 BP 398 EP 417 DI 10.1086/345509 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 639NL UT WOS:000180635900002 ER PT J AU Domingue, DL Sulentic, JW Xu, C Mazzarella, J Gao, Y Rampazzo, R AF Domingue, DL Sulentic, JW Xu, C Mazzarella, J Gao, Y Rampazzo, R TI Multiwavelength insights into mixed-morphology binary galaxies. I. ISOCAM, ISOPHOT, and H alpha imaging SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : elliptical and lenticular, cD; galaxies : ISM; galaxies : photometry; galaxies : spiral ID STAR-FORMATION; INTERACTING GALAXIES; INFRARED-EMISSION; PAIRED GALAXIES; SPIRAL GALAXIES; IONIZED-GAS; IRAS OBSERVATIONS; NUCLEAR ACTIVITY; E+S PAIRS; DISK AB We present H and ISO mid- and far-IR observations for a sample of mixed-morphology galaxy pairs that reveal both the stellar and nonstellar signatures of the interaction process. A mixed-morphology pair is perhaps the simplest form of galaxy-galaxy interaction because it is expected to involve only a single rapidly rotating gas-rich component paired with a gas-poor elliptical or lenticular galaxy. A primary assumption that we address is whether spirals are the only IR emitter in these mixed (E+S) pairs. Our observations reveal that many of the early-type galaxies exhibit weak (low equivalent width) emission, as often observed in field elliptical galaxies. These are the classical mixed-morphology pairs. However, some of the early-type components, especially the lenticular galaxies, show evidence for significant star formation, with H equivalent widths and 15 mum luminosities comparable to or exceeding those of their often much larger spiral companions. Our sample contains five Seyfert 2 nuclei, of which three can be described as companions on the end of a spiral arm. The Seyfert nucleus is often accompanied by a starburst region, while other such companions currently show only the starburst component. These pairs are among the best candidates for direct interaction fuelling of both starbursts and active galactic nuclei. C1 Georgia Coll & State Univ, Dept Chem & Phys, Milledgeville, GA 31061 USA. Univ Alabama, Dept Phys & Astron, Tuscaloosa, AL 35487 USA. CALTECH, Jet Prop Lab, Ctr Infrared Proc & Anal, Pasadena, CA 91125 USA. Osserv Astron Padova, INAF, I-35122 Padua, Italy. Univ Massachusetts, Dept Astron, Amherst, MA 01003 USA. RP Georgia Coll & State Univ, Dept Chem & Phys, CBX 082, Milledgeville, GA 31061 USA. EM domingue@gcsu.edu; giacomo@merlot.astr.ua.edu; cxu@ipac.caltech.edu; mazz@ipac.caltech.edu; gao@ipac.caltech.edu; rampazzo@brera.mi.astro.it OI Rampazzo, Roberto/0000-0001-5318-9183; Domingue, Donovan/0000-0001-5662-7169 NR 69 TC 30 Z9 31 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 FEB PY 2003 VL 125 IS 2 BP 555 EP 571 DI 10.1086/345726 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 639NL UT WOS:000180635900012 ER PT J AU Kataoka, J Edwards, P Georganopoulos, M Takahara, F Wagner, S AF Kataoka, J Edwards, P Georganopoulos, M Takahara, F Wagner, S TI Chandra detection of hotspot and knots of 3C 303 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE galaxies : active; galaxies : individual : 3C 303; galaxies : jets; X-rays : galaxies ID X-RAY JET; EXTRAGALACTIC RADIO-SOURCES; HOT-SPOTS; SHOCK ACCELERATION; COSMIC-RAYS; CYGNUS-A; EMISSION; PKS-0637-752; DISCOVERY; GALAXIES AB We report the detection at X-rays of the radio/optical hotspot and knots of 3C 303 from a short (15 ksec) Chandra exposure in 2001 March. The X-ray morphology is similar to that of the radio/optical emission with peaks in the X-ray emission found at 5.5" (knot B), 9" (knot C) and 17" (hotspot) from the core of 3C 303. Despite the limited signal-to-noise ratio of the short Chandra exposure, the X-ray photon spectrum was measured for the hotspot. We construct the spectral energy distribution (SED) and find that the X-ray flux is well below the extrapolation of the radio-to-optical continuum, which we interpret as resulting from the production of X-rays via inverse Compton scattering of both synchrotron photons (SSC) and cosmic microwave background photons (EC/CMB). The magnetic field strength, region size, and the maximum energy of electrons are self-consistently determined for the hotspot to be B similar or equal to 4.3 muG, R similar or equal to 6.5 x 10(21) cm, and gamma(max) similar or equal to 1.4 x 10(7). This implies a magnetic field strength a factor of similar to30 below the equipartition value; B-eq 150 muG. The origin of this large departure from equipartition is still uncertain, but the discrepancy is reduced if the plasma in the hotspot is moving with mildly relativistic speeds. Our observation of 3C 303, as well as recent Chandra detections of large scale jets and hotspots in a number of radio galaxies, confirm that particles are accelerated very efficiently in radio galaxies. C1 Tokyo Inst Technol, Meguro Ku, Tokyo 152, Japan. Inst Space & Astronaut Sci, Kanagawa 229, Japan. NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Osaka Univ, Dept Earth & Space Sci, Osaka, Japan. Landessternwarte Heidelberg, Heidelberg, Germany. RP Kataoka, J (reprint author), Tokyo Inst Technol, Meguro Ku, Tokyo 152, Japan. NR 50 TC 35 Z9 35 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 FEB PY 2003 VL 399 IS 1 BP 91 EP 97 DI 10.1051/0004-6361:20021772 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 642VZ UT WOS:000180827300014 ER PT J AU Charnley, SB Markwick, AJ AF Charnley, SB Markwick, AJ TI Complex bifurcations in interstellar chemistry? SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE ISM : abundances; ISM : molecules; molecular processes ID BISTABILITY AB Bifurcation diagrams for the steady-state chemical abundances of dense molecular gas have been computed in the region of parameter space where bistable solutions are known to occur. Despite the appearance of many exotic bifurcations, which could be interpreted as sections though higher dimensional catastrophes, we show that they are fundamentally projection effects of the same basic bifurcation, which is an hysteresis loop. C1 UMIST, Dept Phys, Manchester M60 1QD, Lancs, England. NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. RP Markwick, AJ (reprint author), UMIST, Dept Phys, POB 88, Manchester M60 1QD, Lancs, England. RI Charnley, Steven/C-9538-2012 NR 14 TC 6 Z9 6 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 FEB PY 2003 VL 399 IS 2 BP 583 EP 587 DI 10.1051/0004-6361:20021533 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 643JW UT WOS:000180859000019 ER PT J AU Schmitz, F Fleck, B AF Schmitz, F Fleck, B TI Towards an explanation of features in the diagnostic diagram of a model atmosphere - I. Linear wave equations with convenient invariants SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE Sun : atmosphere; Sun : oscillations; stars : atmospheres ID OSCILLATIONS; STRATIFICATION AB New standard forms of the time-independent linear adiabatic wave equation of plane atmospheres are presented. The main objective is to obtain equations with invariants as simple as possible so that oscillation theorems can be applied effectively. By transformations of both the independent and the dependent variables, equations with simple invariants are formulated. We present a standard form of the wave equation the invariant of which depends only on the first derivative of the equilibrium density, as opposed to the common standard form the invariant of which depends also on second derivatives. Further, we discuss a procedure which replaces the wave equation by a system of two simple second order differential equations. In this case we try to draw conclusions on the general behavior of solutions by use of oscillation theorems. In addition, a re-formulation of the wave equation is presented, which eliminates terms with first derivatives of atmospheric quantities. The independent variable of the resulting equation depends not only on the geometrical height but also on the ratio omega/k. In this case, it is necessary to use a diagnostic diagram the axes of which are given by omega/k and ! instead of the common k-omega diagram. Therefore we discuss the meaning of the parameter omega/k for the representation of dispersion curves. Finally, for the VAL-atmosphere (Vernazza et al. 1981), regions of certainly nonoscillatory waves are considered. C1 Univ Wurzburg, Inst Theoret Phys & Astrophys, D-97074 Wurzburg, Germany. NASA, Goddard Space Flight Ctr, ESA, Res & Sci Support Dept, Greenbelt, MD 20771 USA. RP Univ Wurzburg, Inst Theoret Phys & Astrophys, Am Hubland, D-97074 Wurzburg, Germany. RI Fleck, Bernhard/C-9520-2012 NR 20 TC 6 Z9 7 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 FEB PY 2003 VL 399 IS 2 BP 723 EP 730 DI 10.1051/0004-6361:20021815 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 643JW UT WOS:000180859000035 ER PT J AU Odenwald, S Kashlinsky, A Mather, JC Skrutskie, MF Cutri, RM AF Odenwald, S Kashlinsky, A Mather, JC Skrutskie, MF Cutri, RM TI Analysis of the diffuse near-infrared emission from Two-Micron All-Sky Survey deep integration data: Foregrounds versus the cosmic infrared background SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : observations; diffuse radiation; galaxies : evolution; large-scale structure of universe ID COBE DIRBE MAPS; GALAXY FORMATION; LIGHT; DUST; EVOLUTION; LIMITS; 2MASS; MODEL; C(0) AB This is one of two papers in which we report the detection of structure in the cosmic infrared background (CIB) between 1.25 and 2.2 mum through the use of data from the Two-Micron All-Sky Survey (2MASS). This paper concentrates on data assembly, analysis, and the estimate of the various foreground contributions; the companion Letter presents the cosmological results for the CIB fluctuations and their implications. By using repeated observations of a specific calibration star field, we were able to achieve integration times in excess of 3900 s, compared to the 7.8 s in the standard 2MASS data product. This yielded a point-source detection limit (3sigma) of +18.5 mag in the K-s band. The resulting co-added images were processed to remove point sources to a limiting surface brightness of +20 mag arcsec(-2) or 40 nW m(-2) sr(-1). The remaining maps contained over 90% of the pixels and were Fourier transformed to study the spatial structure of the diffuse background light. After removing resolved sources and other artifacts, we find that the power spectrum of the final images has a power-law distribution consistent with clustering by distant galaxies. We estimate here the contributions to this signal from Galactic foregrounds, atmospheric OH-glow, zodiacal light, and instrument noise, all of which are small and of different slopes. This supports the identification offered in the companion Letter of the signal as coming from the CIB fluctuations produced by distant clustered galaxies. C1 NASA, Goddard Space Flight Ctr, Sci & Syst Applicat Inc, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Raytheon ITSS, Greenbelt, MD 20771 USA. Univ Virginia, Dept Astron, Charlottesville, VA 22903 USA. Ctr Infrared Proc & Anal, Pasadena, CA USA. RP Kashlinsky, A (reprint author), NASA, Goddard Space Flight Ctr, Sci & Syst Applicat Inc, Code 685, Greenbelt, MD 20771 USA. NR 33 TC 21 Z9 21 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 1 PY 2003 VL 583 IS 2 BP 535 EP 550 DI 10.1086/345401 PN 1 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 639NP UT WOS:000180636300003 ER PT J AU LaRoque, SJ Joy, M Carlstrom, JE Ebeling, H Bonamente, M Dawson, KS Edge, A Holzapfel, WL Miller, AD Nagai, D Patel, SK Reese, ED AF LaRoque, SJ Joy, M Carlstrom, JE Ebeling, H Bonamente, M Dawson, KS Edge, A Holzapfel, WL Miller, AD Nagai, D Patel, SK Reese, ED TI Sunyaev-Zeldovich effect imaging of MACS galaxy clusters at z > 0.5 SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic microwave background; cosmology : observations; galaxies : clusters : general; submillimeter; techniques : interferometric; X-rays : galaxies : clusters ID X-RAY-CLUSTERS; CONSTRAINTS; RADIATION; UNIVERSE AB We present 30 GHz interferometric Sunyaev-Zeldovich effect (SZE) measurements of a redshift-limited, X-ray selected cluster sample from the Massive Cluster Survey ( MACS). All eight of the high-redshift (z > 0.5, delta > -15degrees) galaxy clusters were detected. Additional observations were made at 4.8 GHz with the Very Large Array to help constrain the amount of point source contamination to the SZE decrements. From SZE data alone, we derive electron temperatures in the range 5.5-18.5 keV and total masses between 1.5 and 2.6 x 10(14) h(-1) M. within a 65" radius (0.28 h(-1) Mpc at z = 0.5) for the eight clusters. Six of the clusters are MACS discoveries, while two (Cl 0016+1609 and MS 0451.6-0305) were detected by previous X-ray observations and have been recently observed with the Chandra observatory. The X-ray derived temperatures and masses for Cl 0016+ 1609 and MS 0451.6-0305 are in good agreement with the SZE derived values. Strong detections of the SZE signal in this sample of MACS objects confirm that they are hot, massive clusters. C1 Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. NASA, George C Marshall Space Flight Ctr, Dept Space Sci, Huntsville, AL 35812 USA. Univ Chicago, Enrico Fermi Inst, Dept Phys, Ctr Cosmol Phys, Chicago, IL 60637 USA. Astron Inst, Honolulu, HI 96822 USA. Univ Alabama, Dept Phys, Huntsville, AL 35899 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Durham, Dept Phys, Durham DH1 3LE, England. Columbia Univ, Dept Phys, New York, NY 10027 USA. Natl Acad Sci, NRC, NSSTC, Huntsville, AL 35805 USA. RP LaRoque, SJ (reprint author), Univ Chicago, Dept Astron & Astrophys, 5640 S Ellis Ave, Chicago, IL 60637 USA. RI Holzapfel, William/I-4836-2015 NR 31 TC 40 Z9 40 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 FEB 1 PY 2003 VL 583 IS 2 BP 559 EP 565 DI 10.1086/345500 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 639NP UT WOS:000180636300005 ER PT J AU Hudson, DS Henriksen, MJ Colafrancesco, S AF Hudson, DS Henriksen, MJ Colafrancesco, S TI A BeppoSAX observation of the IC 1262 galaxy cluster SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : clusters : individual (IC 1262) intergalactic medium; radiation mechanisms : nonthermal; X-rays : galaxies ID X-RAY-EMISSION; COMA-CLUSTER; RADIO-SOURCES; RADIATION; ACCELERATION; ELECTRONS; SPECTRUM; MERGER; ENERGY; ORIGIN AB We present an analysis of BeppoSAX observations of the IC 1262 galaxy cluster and report the first temperature and abundance measurements, along with preliminary indications of diffuse, nonthermal emission. By fitting a 6' (similar to360 h(50)(-1) kpc) region with a single Mewe-Kaastra-Liedahl model with photoelectric absorption, we find a temperature of 2.1-2.3 keV and an abundance of 0.45-0.77 (both 90% confidence). We find that the addition of a power-law component provides a statistically significant improvement (F-test = 90%) to the fit. The addition of a second thermal component also improves the fit, but we argue that it is physically implausible. The power-law component has a photon index (Gamma(X)) of 0.4-2.8 and a nonthermal flux of (4.1-56.7) x 10(-5) photons cm(-2) s(-1) over the 1.5-10.5 keV range in the Medium Energy Concentrator Spectrometer detector. An unidentified X-ray source found in the ROSAT High Resolution Imager observation (similar to0.'9 from the center of the cluster) is a possible explanation for the nonthermal flux; however, additional evidence of diffuse, nonthermal emission comes from the NRAO VLA Sky Survey and the Westerbork Northern Sky Survey radio measurements, in which excess diffuse radio flux is observed after point-source subtraction. The radio excess can be fitted to a simple power law with a spectral index of similar to1.8, which is consistent with the nonthermal X-ray emission spectral index. The steep spectrum is typical of diffuse emission, and the size of the radio source implies that it is larger than the cD galaxy and not due to a discreet source. C1 Univ Maryland Baltimore Cty, Dept Phys, Baltimore, MD 21250 USA. Univ Maryland Baltimore Cty, Dept Phys, Joint Ctr Astrophys, Baltimore, MD 21250 USA. Osserv Astron Roma, I-00040 Monte Porzio Catone, Italy. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Univ Maryland Baltimore Cty, Dept Phys, 1000 Hilltop Circle, Baltimore, MD 21250 USA. NR 38 TC 8 Z9 8 U1 1 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD FEB 1 PY 2003 VL 583 IS 2 BP 706 EP 711 DI 10.1086/345492 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 639NP UT WOS:000180636300018 ER PT J AU Swaters, RA Madore, BF van den Bosch, FC Balcells, M AF Swaters, RA Madore, BF van den Bosch, FC Balcells, M TI The central mass distribution in dwarf and low surface brightness galaxies SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : dwarf; galaxies : halos; galaxies : kinematics and dynamics ID DARK-MATTER HALOS; RESOLUTION ROTATION CURVES; SPIRAL GALAXIES; BARYONIC INFALL; DISC GALAXIES; H-I; MODELS; NGC-3198; NGC-5585; PROFILES AB We present high-resolution Halpha rotation curves for a sample of 15 dwarf and low surface brightness galaxies. From these we derive limits on the slopes of the central mass distributions, using both a direct inversion of the rotation curves and detailed mass models. Assuming that the density distributions of dark matter halos follow a power law at small radii, rho(r) proportional to r(-alpha), we find inner slopes in the range 0 less than or similar to alpha less than or similar to 1 for most galaxies. Thus, even with the relatively high spatial resolution of the H rotation curves presented here, the inner slopes are poorly constrained. In general halos with constant density cores (alpha = 0) provide somewhat better fits, but the majority of our galaxies (similar to75%) are also consistent with alpha = 1, as long as the R-band stellar mass-to-light ratios are smaller than about 2. Halos with alpha = 1.5, however, are ruled out in virtually every case. In order to investigate the robustness of these results we discuss and model several possible causes of systematic errors, including noncircular motions, galaxy inclination, slit width, seeing, and slit alignment errors. Taking the associated uncertainties into account, we conclude that even for the similar to25% of the cases where alpha = 1 seems inconsistent with the rotation curves, we cannot rule out cusp slopes this steep. Inclusion of literature samples similar to the one presented here leads to the same conclusion when the possibility of systematic errors is taken into account. In the ongoing debate on whether the rotation curves of dwarf and low surface brightness galaxies are consistent with predictions for a cold dark matter universe, we argue that our sample and the literature samples discussed in this paper provide insufficient evidence to rule out halos with alpha = 1. At the same time, we note that none of the galaxies in these samples require halos with steep cusps, as most are equally well or better explained by halos with constant density cores. C1 Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. CALTECH, NASA, IPAC Extragalact Database, Pasadena, CA 91125 USA. Max Planck Inst Astrophys, D-85741 Garching, Germany. Inst Astrofis Canarias, E-38200 San Cristobal la Laguna, Spain. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Carnegie Inst Washington, Dept Terr Magnetism, Washington, DC 20015 USA. Observ Carnegie Inst Washington, Pasadena, CA 91101 USA. RP Swaters, RA (reprint author), Johns Hopkins Univ, Dept Phys & Astron, 3400 N Charles St, Baltimore, MD 21218 USA. NR 64 TC 270 Z9 271 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 FEB 1 PY 2003 VL 583 IS 2 BP 732 EP 751 DI 10.1086/345426 PN 1 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 639NP UT WOS:000180636300021 ER PT J AU Kallman, TR Angelini, L Boroson, B Cottam, J AF Kallman, TR Angelini, L Boroson, B Cottam, J TI Chandra and XMM observations of the accretion disk corona source 2S 0921-63 SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; stars : individual (2S 0921 63); X-rays : binaries; X-rays : individual (2S 0921 63) ID X-RAY BINARIES; COMPTON HEATED WINDS; EMISSION-LINES; SPECTRA; PHOTOIONIZATION; IONS AB We analyze observations of the low-mass X-ray binary (LMXB) 2S 0921-63 obtained with the gratings and CCDs on Chandra and XMM. This object is a high-inclination system showing evidence for an accretion disk corona (ADC). Such a corona has the potential to constrain the properties of the heated accretion disk in this system and other LMXBs by extension. We find evidence for line emission that is generally consistent with that found by previous experiments, although we are able to detect more lines. For the first time in this source, we find that the iron K line has multiple components. We set limits on the line widths and velocity offsets, and we fit the spectra to photoionization models and discuss the implications for ADC models. For the first time in any ADC source we use these fits, together with density constraints based on the O VII line ratio, in order to constrain the flux in the medium-ionization region of the ADC. Under various assumptions about the source luminosity this constrains the location of the emitting region. These estimates, together with estimates for the emission measure, favor a scenario in which the intrinsic luminosity of the source is comparable to what we observe. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Univ Space Res Assoc, Columbia, MD 21044 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Kallman, TR (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Code 665, Greenbelt, MD 20771 USA. NR 32 TC 24 Z9 25 U1 1 U2 5 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 1 PY 2003 VL 583 IS 2 BP 861 EP 877 DI 10.1086/345475 PN 1 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 639NP UT WOS:000180636300033 ER PT J AU Novak, G Chuss, DT Renbarger, T Griffin, GS Newcomb, MG Peterson, JB Loewenstein, RF Pernic, D Dotson, JL AF Novak, G Chuss, DT Renbarger, T Griffin, GS Newcomb, MG Peterson, JB Loewenstein, RF Pernic, D Dotson, JL TI First results from the submillimeter polarimeter for Antarctic remote observations: Evidence of large-scale toroidal magnetic fields in the Galactic center SO ASTROPHYSICAL JOURNAL LA English DT Article DE Galaxy : center; ISM : magnetic fields; polarization ID CENTER REGION; CENTER LOBES; CENTER ARC; RADIO ARC; FILAMENTS AB We have observed the linear polarization of 450 mum continuum emission from the Galactic center, using a new polarimetric detector system that is operated on a 2 m telescope at the South Pole. The resulting polarization map extends similar to170 pc along the Galactic plane and similar to30 pc in Galactic latitude, and thus covers a significant fraction of the central molecular zone. Our map shows that this region is permeated by large-scale toroidal magnetic fields. We consider our results together with radio observations that show evidence of poloidal fields in the Galactic center and with Faraday rotation observations. We compare all of these observations with the predictions of a magnetodynamic model for the Galactic center that was proposed in order to explain the Galactic Center Radio Lobe as a magnetically driven gas outflow. We conclude that the observations are fundamentally consistent with the model. C1 Northwestern Univ, Dept Phys & Astron, Evanston, IL 60208 USA. Carnegie Mellon Univ, Dept Phys, Pittsburgh, PA 15213 USA. Univ Chicago, Yerkes Observ, Williams Bay, WI 53191 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Novak, G (reprint author), Northwestern Univ, Dept Phys & Astron, 2145 Sheridan Rd, Evanston, IL 60208 USA. RI Chuss, David/D-8281-2012; Peterson, Jeffrey/O-4794-2014 OI Peterson, Jeffrey/0000-0003-1340-818X NR 23 TC 72 Z9 72 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 FEB 1 PY 2003 VL 583 IS 2 BP L83 EP L86 DI 10.1086/368156 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 639NR UT WOS:000180636500009 ER PT J AU Swartz, DA Ghosh, KK McCollough, ML Pannuti, TG Tennant, AF Wu, K AF Swartz, DA Ghosh, KK McCollough, ML Pannuti, TG Tennant, AF Wu, K TI Chandra X-ray observations of the spiral galaxy M81 SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Review DE galaxies : individual (M81); supernovae : individual (SN 1993J); X-rays : binaries; X-rays : galaxies; X-rays : stars ID H-II REGIONS; ULTRAVIOLET IMAGING TELESCOPE; EXTRAGALACTIC DISTANCE SCALE; SN 1993J; SUPERNOVA-REMNANTS; GLOBULAR-CLUSTERS; SEYFERT-GALAXIES; NEUTRAL-HYDROGEN; RADIO-CONTINUUM; ALPHA-EMISSION AB A Chandra X-Ray Observatory ACIS-S imaging observation is used to study the population of X-ray sources in the nearby Sab galaxy M81 (NGC 3031). A total of 177 sources are detected with 124 located within the D(25) isophote to a limiting X-ray luminosity of similar to3x10(36) ergs s(-1). Source positions, count rates, luminosities in the 0.3-8.0 keV band, limiting optical magnitudes, and potential counterpart identifications are tabulated. Spectral and timing analysis of the 36 brightest sources are reported including the low-luminosity active galactic nucleus, SN 1993J, and the Einstein-discovered ultraluminous X-ray source X6. The nucleus accounts for similar to86%, or 5x10(40) ergs s(-1), of the total X-ray emission from M81. Its spectrum is well fitted by an absorbed power law with photon index 1.98+/-0.08, consistent with previous observations ( average index 1.9). SN 1993J has softened and faded since its discovery. At an age of 2594 days, SN 1993J displayed a complex thermal spectrum from a reverse shock rich in Fe L and highly ionized Mg, Si, and S but lacking O. A hard X-ray component, emitted by a forward shock, is also present. X6 is spatially coincident with a stellar object with optical brightness and colors consistent with an O9-B1 main-sequence star. It is also coincident with a weak radio source with a flux density of similar to95 muJy at lambda=3.6 cm. The continuum-dominated X-ray spectrum of X6 is most closely reproduced by a blackbody disk model suggesting the X-ray source is an similar to18 M(circle dot) object accreting at nearly its Eddington limit. The non-nuclear point source population of M81 accounts for 88% of the non-nuclear X-ray luminosity of 8.1x10(39) ergs s(-1). The remaining (unresolved) X-ray emission is confined within similar to2 kpc of the galactic center. The spatial distribution of this emission and of the resolved X-ray bulge sources closely follows that of the bulge optical light. In particular, there is no evidence for an X-ray signature accompanying the filamentary Halpha or excess UV emission seen in the central less than or similar to1.0 kpc of the galaxy. The shape of the luminosity function of the bulge sources is a power law with a break at similar to4x10(37) ergs s(-1); suggesting the presence of an aging (similar to400 Myr) population of low-mass X-ray binaries. Extrapolating this luminosity function to lower luminosities accounts for only similar to10% of the unresolved X-ray emission. Spectroscopically, the unresolved emission can be represented as a combination of soft, kTsimilar to0.3 keV, optically thin plasma emission and of a Gamma=1.6 power law. The unresolved bulge X-ray emission is therefore most likely a combination of hot gas and of one or more large and distinct populations of low-luminosity X-ray sources confined in the gravitational potential and tracing the old population of bulge stars. The distribution of disk sources shows a remarkably strong correlation with spiral arms with the brightest disk sources located closest to spiral arms. The luminosity function of sources near the spiral arms is a pure power law (slope-0.48+/-0.03), while that of sources further away exhibits a break or cutoff in the power-law distribution with no high-luminosity members. This is interpreted as a natural consequence of the passage of spiral density waves that leave the brightest ( when averaged over their lifetimes) and shortest-lived X-ray sources immediately downstream of the spiral arms. Consistent with model predictions, we conclude that the shapes of the X-ray luminosity functions of the different galactic components of M81 are most likely governed by the birth rates and lifespans of their constituent X-ray source populations and that the luminosity functions can be used as a measure of the star formation histories of their environments. C1 NASA, Univ Space Res Assoc, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. MIT, Ctr Space Res, Cambridge, MA 02139 USA. NASA, Dept Space Sci, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. UCL, Mullard Space Sci Lab, Holmbury RH5 6NT, Surrey, England. RP Swartz, DA (reprint author), NASA, Univ Space Res Assoc, George C Marshall Space Flight Ctr, SD50, Huntsville, AL 35812 USA. NR 129 TC 84 Z9 84 U1 1 U2 4 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 FEB PY 2003 VL 144 IS 2 BP 213 EP 242 DI 10.1086/345084 PG 30 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 636ME UT WOS:000180459200001 ER PT J AU Burden, HW Zary, JT Hodson, CA Gregory, HL Baer, LA Ronca, AE AF Burden, HW Zary, JT Hodson, CA Gregory, HL Baer, LA Ronca, AE TI Effects of hypergravity on ovarian-hypophyseal function in antepartum and postpartum rats SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article DE pregnancy; follicular atresia; luteolysis ID SERUM LEVELS; PARTURITION; PROLACTIN AB Background: Rats exposed to microgravity during the post-implantation phase of pregnancy had minimal alterations in ovarian and hypophyseal parameters during the antepartum and postpartum periods. In the current study, a similar parallel experimental design was employed to ascertain the effects of hypergravity on ovarian and hypophyseal function. Hypothesis: We hypothesized that hypergravity exposure during the post-implantation stage of pregnancy would not alter antepartum and postpartum ovarian and hypophyseal function. Methods: Pregnant rats were assigned to hypergravity (1.5 G, 1.75 G, or 2.0 G), rotational control, or stationary control groups (n = 10 each group) beginning on gestation day 11 and ending on day 20. Hypophyseal and ovarian analyses were conducted on 5 of the animals from each group at day 20. The remaining animals in each group were allowed to go to term and the same analyses were conducted 3 h postpartum. Results: Hypergravity at all levels decreased the percent body mass gain from gestation day 11 to 20 (p < 0.05); however, the wet weight of the pituitaries and ovaries was not changed. There was no effect of hypergravity on the number of healthy or atretic antral follicles of any size at gestation day 20 or postpartum. The number of corpora lutea of pregnancy was decreased in all hypergravity groups, but the number of live fetuses at gestation day 20 or pups at term was not altered. Plasma concentrations of luteinizing hormone (LH), follicle stimulating hormone (FSH), prolactin, and progesterone were not changed at gestation day 20 or postpartum. Pituitary content of LH, FSH, and prolactin was not altered by hypergravity at gestation day 20, but LH content was significantly increased (p < 0.05) at 1.5 and 1.75 G postpartum. Conclusions: We conclude that hypergravity, up to and including 2.0 G, is compatible with maintenance of pregnancy and has minimal effects on hypophyseal parameters. Ovarian follicles are not altered by hypergravity, but corpora lutea may regress at a more rapid rate. C1 E Carolina Univ, Brody Sch Med, Dept Anat & Cell Biol, Greenville, NC 27858 USA. E Carolina Univ, Brody Sch Med, Dept Obstet & Gynecol, Greenville, NC 27858 USA. NASA, Div Life Sci, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Burden, HW (reprint author), E Carolina Univ, Brody Sch Med, Dept Anat & Cell Biol, Greenville, NC 27858 USA. NR 32 TC 1 Z9 1 U1 0 U2 0 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 USA SN 0095-6562 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD FEB PY 2003 VL 74 IS 2 BP 110 EP 114 PG 5 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA 640WD UT WOS:000180710300002 PM 12602441 ER PT J AU Lewis, MA Etienne-Cummings, R Hartmann, MJ Xu, ZR Cohen, AH AF Lewis, MA Etienne-Cummings, R Hartmann, MJ Xu, ZR Cohen, AH TI An in silico central pattern generator: silicon oscillator, coupling, entrainment, and physical computation SO BIOLOGICAL CYBERNETICS LA English DT Article ID MUSCULO-SKELETAL SYSTEM; HUMAN LOCOMOTION; MODEL AB In biological systems, the task of computing a gait trajectory is shared between the biomechanical and nervous systems. We take the perspective that both of these seemingly different computations are examples of physical computation. Here we describe the progress that has been made toward building a minimal biped system that illustrates this idea. We embed a significant portion of the computation in physical devices, such as capacitors and transistors, to underline the potential power of emphasizing the understanding of physical computation. We describe results in the exploitation of physical computation by (1) using a passive knee to assist in dynamics computation, (2) using an oscillator to drive a monoped mechanism based on the passive knee, (3) using sensory entrainment to coordinate the mechanics with the neural oscillator, (4) coupling two such systems together mechanically at the hip and computationally via the resulting two oscillators to create a biped mechanism, and (5) demonstrating the resulting gait generation in the biped mechanism. C1 Iguana Robot Inc, Mahomet, IL 61853 USA. Johns Hopkins Univ, Dept Elect & Comp Engn, Baltimore, MD 21218 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Maryland, Dept Biol Neurosci & Cognit Sci, College Pk, MD 20742 USA. Johns Hopkins Univ, Dept Elect & Comp Engn, Baltimore, MD 21218 USA. RP Lewis, MA (reprint author), Iguana Robot Inc, POB 628, Mahomet, IL 61853 USA. RI Hartmann, Mitra/A-8150-2008; Hartmann, Mitra/B-6766-2009; Etienne-Cummings, Ralph/A-3227-2010 NR 25 TC 56 Z9 58 U1 0 U2 4 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0340-1200 J9 BIOL CYBERN JI Biol. Cybern. PD FEB PY 2003 VL 88 IS 2 BP 137 EP 151 DI 10.1007/s00422-002-0365-7 PG 15 WC Computer Science, Cybernetics; Neurosciences SC Computer Science; Neurosciences & Neurology GA 655DJ UT WOS:000181535800006 PM 12567228 ER PT J AU Metcalfe, A Desfaits, AC Salazkin, I Yahia, L Sokolowski, WM Raymond, J AF Metcalfe, A Desfaits, AC Salazkin, I Yahia, L Sokolowski, WM Raymond, J TI Cold hibernated elastic memory foams for endovascular interventions SO BIOMATERIALS LA English DT Article DE polyurethane; shape memory polymer (SMP); cold hibernated elastic memory (CHEM); aneurysm; endovascular; embolization ID EXPERIMENTAL ANEURYSMS; IN-VITRO; BIOMEDICAL APPLICATIONS; EMBOLIZATION; NEOINTIMA; CELLS; POLYURETHANES; MECHANISMS; THICKNESS; INCREASE AB Cold hibernated elastic memory (CHEM) polyurethane-based foam is a new shape memory polymeric self-deployable structure. Standard cytotoxicity and mutagenicity tests were conducted on CHEM in vitro, to ensure biocompatibility before studying potential medical applications. In vivo, lateral wall aneurysms were constructed on both carotid arteries of eight dogs. Aneurysms were occluded per-operatively with CHEM blocks. In two dogs, CHEM embolization was compared with gelatin sponge fragment embolization. Internal maxillary arteries (Imax) were also occluded with CHEM using a 6F transcatheter technique. Angiography and pathology were used to study the evolution of aneurysms and Imax at 3 and 12 weeks. Imax embolized with CHEM foam remained occluded at 3 weeks. Most aneurysms embolized with CHEM showed a small residual crescent of opacification at initial angiography, but angiographic scores were significantly better at 3 weeks. Thick neointima formation over the CHEM at the neck of aneurysms was demonstrated at pathology. The foamy nature of CHEM favours the ingrowth of cells involved in neointima formation. New devices for endovascular interventions could be designed using CHEM's unique physical properties. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 CHUM, Intervent Neuroradiol Lab, Res Ctr, Notre Dame Hosp, Montreal, PQ H2L 4M1, Canada. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Ecole Polytech, Inst Biomed Engn, Montreal, PQ H3C 3A7, Canada. RP Metcalfe, A (reprint author), CHUM, Intervent Neuroradiol Lab, Res Ctr, Notre Dame Hosp, Mailloux Pavil M-8206,1560 Sherbrooke E, Montreal, PQ H2L 4M1, Canada. RI Raymond, Jean/D-3940-2011 NR 34 TC 162 Z9 163 U1 1 U2 43 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0142-9612 J9 BIOMATERIALS JI Biomaterials PD FEB PY 2003 VL 24 IS 3 BP 491 EP 497 AR PII S0142-9612(02)00362-9 DI 10.1016/S0142-9612(02)00362-9 PG 7 WC Engineering, Biomedical; Materials Science, Biomaterials SC Engineering; Materials Science GA 617VV UT WOS:000179382300013 PM 12423604 ER PT J AU Pusey, ML Gorti, S Forsythe, E Konnert, J AF Pusey, ML Gorti, S Forsythe, E Konnert, J TI AFM studies of salt concentration effects on the (110) surface structure of tetragonal lysozyme crystals SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract CT 47th Annual Meeting of the Biophysical-Society CY MAR 01-05, 2003 CL SAN ANTONIO, TEXAS SP Biophys Soc, Axon Instruments, ALA Sci Instruments C1 NASA, MSFC, Huntsville, AL 35812 USA. Univ Space Res Adm, Huntsville, AL 35806 USA. USN, Res Lab, Lab Struct Matter, Washington, DC 20375 USA. NR 0 TC 0 Z9 0 U1 0 U2 3 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 2003 VL 84 IS 2 SU S BP 43A EP 43A PN 2 PG 1 WC Biophysics SC Biophysics GA 682ZW UT WOS:000183123800203 ER PT J AU Sumida, JP Pusey, ML AF Sumida, JP Pusey, ML TI Changes in the molar ellipticities of HEWL observed by circular dichroism and quantitated by time resolved fluorescence anisotropy under crystallizing conditions. SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract CT 47th Annual Meeting of the Biophysical-Society CY MAR 01-05, 2003 CL SAN ANTONIO, TEXAS SP Biophys Soc, Axon Instruments, ALA Sci Instruments C1 USRA, Huntsville, AL 35803 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 2003 VL 84 IS 2 SU S BP 502A EP 502A PN 2 PG 1 WC Biophysics SC Biophysics GA 682ZW UT WOS:000183123802464 ER PT J AU Segovia-Juarez, JL Colombano, S AF Segovia-Juarez, JL Colombano, S TI The effect of molecular inhibition on evolutionary learning: studies in the hypernetwork architecture SO BIOSYSTEMS LA English DT Article; Proceedings Paper CT 4th International Workshop on Information Processing in Cells and Tissues CY AUG 13-17, 2001 CL LEUVEN, BELGIUM DE evolutionary learning; molecular regulation; inhibition; biological information processing; homeostasis ID NETWORKS; GUIDANCE; PATHWAY; GROWTH AB The hypernetwork architecture is a biologically inspired learning model based on abstract molecules and molecular interactions that exhibits functional and organizational correlation with biological systems. Hypernetwork organisms were trained, by molecular evolution, to solve N-input parity tasks. We found that learning improves when molecules exhibit inhibitory sites, allowing molecular inhibition and opening the possibility of forming negative feedback regulatory pathways. Optimal learning is achieved when at least 20% of the molecules in each cell have inhibitory sites. Intra-cellular as well as inter-cellular molecular inhibitions play an important role in the information processing of hypernetwork organisms, by maintaining a balance of the molecular cascade reactions. Similar mechanisms inside neurons are considered important for memory. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved. C1 Wayne State Univ, Dept Comp Sci, Biocomp Lab, Detroit, MI 48202 USA. NASA, Ames Res Ctr, Computat Sci Div, Moffett Field, CA 94035 USA. RP Segovia-Juarez, JL (reprint author), Wayne State Univ, Dept Comp Sci, Biocomp Lab, 431 State Hall, Detroit, MI 48202 USA. OI Segovia-Juarez, Jose/0000-0002-3332-5886 NR 36 TC 1 Z9 2 U1 0 U2 5 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0303-2647 J9 BIOSYSTEMS JI Biosystems PD FEB-MAR PY 2003 VL 68 IS 2-3 BP 187 EP 198 AR PII S0303-2647(02)00095-3 DI 10.1016/S0303-2647(02)00095-3 PG 12 WC Biology; Mathematical & Computational Biology SC Life Sciences & Biomedicine - Other Topics; Mathematical & Computational Biology GA 673WD UT WOS:000182602500008 PM 12595117 ER PT J AU Revercomb, HE Turner, DD Tobin, DC Knuteson, RO Feltz, WF Barnard, J Bosenberg, J Clough, S Cook, D Ferrare, R Goldsmith, J Gutman, S Halthore, R Lesht, B Liljegren, J Linne, H Michalsky, J Morris, V Porch, W Richardson, S Schmid, B Splitt, M Van Hove, T Westwater, E Whiteman, D AF Revercomb, HE Turner, DD Tobin, DC Knuteson, RO Feltz, WF Barnard, J Bosenberg, J Clough, S Cook, D Ferrare, R Goldsmith, J Gutman, S Halthore, R Lesht, B Liljegren, J Linne, H Michalsky, J Morris, V Porch, W Richardson, S Schmid, B Splitt, M Van Hove, T Westwater, E Whiteman, D TI The ARM program's water vapor intensive observation periods - Overview, initial accomplishments, and future challenges SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID RAMAN LIDAR; METEOROLOGICAL APPLICATIONS; ATMOSPHERIC RADIATION; PRECIPITABLE WATER; COOLING RATES; GPS; TEMPERATURE; AEROSOLS; ACCURACY; NETWORK AB Results from a series of experiments focused on the lower troposphere have pointed,the way to significantly improving the accuracy of water vapor measurements. C1 Univ Wisconsin, Madison, WI 53706 USA. Pacific NW Natl Lab, Richland, WA USA. Max Planck Inst Meteorol, Hamburg, Germany. Atmospher & Environm Res Inc, Lexington, MA USA. Argonne Natl Lab, Argonne, IL 60439 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. Sandia Natl Labs, Livermore, CA 94551 USA. USN, Res Lab, Monterey, CA USA. SUNY Albany, Albany, NY 12222 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Cooperat Inst Mesoscale Meteorol Studies, Norman, OK USA. Univ Oklahoma, Norman, OK 73019 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Utah, Salt Lake City, UT 84132 USA. Univ Colorado, Cooperat Atmospher Res, Boulder, CO 80309 USA. Univ Colorado, NOAA, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Turner, DD (reprint author), Univ Wisconsin, 1225 W Dayton St, Madison, WI 53706 USA. RI Linne, Holger/J-8510-2014 OI Linne, Holger/0000-0003-3188-0429 NR 50 TC 101 Z9 109 U1 0 U2 4 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD FEB PY 2003 VL 84 IS 2 BP 217 EP 236 DI 10.1175/BAMS-84-2-217 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 649CH UT WOS:000181189000019 ER PT J AU Stephenson, DB Pavan V AF Stephenson, DB Pavan, V TI The North Atlantic Oscillation in coupled climate models: a CMIP1 evaluation SO CLIMATE DYNAMICS LA English DT Article ID GENERAL-CIRCULATION MODEL; SURFACE AIR-TEMPERATURE; SEA-ICE; OCEAN; HEMISPHERE; VARIABILITY; EUROPE; TRENDS; ENSO; PREDICTABILITY AB This study investigates the North Atlantic Oscillation (NAO) simulated by 17 global coupled ocean-atmosphere models participating in the Coupled Model Intercomparison Project (CMIP). Robust NAO indices are defined by calculating the leading principal components of winter time mean surface temperatures (land and sea) in the North Atlantic region (120degreesW 60degreesE, 20-80degreesN). Encouragingly, 13 out of 17 of the models capture the NAO surface temperature quadrupole pattern with centres of action over Northwest Europe, the northwest Atlantic, the southeastern USA, and the Middle East. The northern dipole is better captured than the southern dipole which is often simulated too far eastwards over the Atlantic Ocean. Out of the 17 models, ten models produce NAO indices that vary similar to the observations as stationary "weakly red noise" with only small correlations between successive winters (r < 0.3). Another five models drift monotonically towards warmer conditions, and two models exhibit long-term stochastic trends. Several of the models significantly overestimate the teleconnection between NAO and the tropical ENSO phenomenon. C1 Univ Reading, Dept Meteorol, Reading RG6 6BB, Berks, England. ARPA, SMR, I-40122 Bologna, Italy. Canadian Ctr Climate Modelling & Anal, Victoria, BC, Canada. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. German Climate Comp Ctr, Hamburg, Germany. CNRS, Meteorol Dynam Lab, Paris, France. United Kingdom Meteorol Off, Hadley Ctr, Bracknell, Berks, England. Ctr Climate Syst Res, Tokyo, Japan. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. Goddard Inst Space Studies, New York, NY USA. Meteorol Res Inst, Ibaraki, Japan. German Climate Comp Ctr, Hamburg, Germany. Bur Meteorol Res Ctr, Melbourne, Vic, Australia. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Geophys Fluid Dynam Lab, Princeton, NJ USA. CERFACS, Global Change Team, F-31057 Toulouse, France. Chinese Acad Sci, LASG, IAP, Beijing, Peoples R China. RP Stephenson, DB (reprint author), Univ Reading, Dept Meteorol, POB 243,Earley Gate, Reading RG6 6BB, Berks, England. EM D.B.stephenson@reading.ac.uk RI Stephenson, David/A-9903-2011 NR 56 TC 27 Z9 31 U1 0 U2 5 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0930-7575 J9 CLIM DYNAM JI Clim. Dyn. PD FEB PY 2003 VL 20 IS 4 BP 381 EP 399 DI 10.1007/s00382-002-0281-5 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 657HA UT WOS:000181659300005 ER PT J AU Chen, B Chao, WC Liu, X AF Chen, B Chao, WC Liu, X TI Enhanced climatic warming in the Tibetan Plateau due to doubling CO2: a model study SO CLIMATE DYNAMICS LA English DT Article ID OCEAN-ATMOSPHERE MODEL; CARBON-DIOXIDE; CENTRAL-ASIA; MOUNTAINS; MONSOON; REGCM2; SYSTEM AB The National Center for Atmospheric Research (NCAR) regional climate model (RegCM2), together with initial conditions and time-dependent lateral boundary conditions provided by a 130-year transient increasing CO2 simulation of the NCAR Climate System Model (CSM), has been used to investigate the mechanism of ground warming over the Tibetan Plateau (TP). The model results show that when CO2 in the atmosphere is doubled, a strong ground warming occurs in the TP. Two regions within it with the largest warming are in the eastern TP (region I) and along the southwestern and western slopes (region II). Moreover, in region I the ground warming in the winter half year is stronger than that in the summer half year, but in region II the warming difference between the seasons becomes opposite to that in region I, i.e., the warming is strong in the summer half year and weak in the winter half year. There are indications that the summer monsoon enhances but the winter monsoon weakens when CO2 is doubled. A strong elevation dependency of ground warming is found in region I for the winter half year, and in region II for both winter and summer half years at elevations below 5 km. The simulated characteristics of ground warming in the TP are consistent with the observations. In region I, when CO2 is doubled, the cloud amount increases at lower elevations and decreases at higher elevation for the winter half year. As a consequence, at lower elevations the short wave solar radiation absorbed at the surface declines, and the downward long wave flux reaching the surface enhances; on the other hand, at higher elevations the surface solar radiation flux increases and the surface infrared radiation flux shows a more uniform increase. The net effect of the changes in both radiation fluxes is an enhanced surface warming at higher elevations, which is the primary cause of the elevation dependency in the surface warming. In the summer half year the cloud amount reduces as a result of doubling CO2 in region I for all elevations, and there is no elevation dependency detected in the ground warming. Furthermore, there is little snow existing in region I for both summer and winter half years, and the impact of snow-albedo feedback is not significant. In region II, although the changes in the cloud amount bear a resemblance to those in region I, the most significant factor affecting the surface energy budget is the depletion of the snow cover at higher elevations, which leads to a reduction of the surface albedo. This reduction in turn leads to an enhancement in the solar radiation absorbed in the surface. The snow-albedo feedback mechanism is the most essential cause of the elevation dependency in the surface warming for region II. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20711 USA. Univ Maryland, GEST Ctr, Baltimore, MD 21201 USA. Chinese Acad Sci, Inst Earth Environm, Xian, Peoples R China. RP Chen, B (reprint author), NASA, Goddard Space Flight Ctr, Mail Code 913, Greenbelt, MD 20711 USA. RI Liu, Xiaodong/E-9512-2011 OI Liu, Xiaodong/0000-0003-0355-5610 NR 29 TC 67 Z9 81 U1 1 U2 15 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0930-7575 J9 CLIM DYNAM JI Clim. Dyn. PD FEB PY 2003 VL 20 IS 4 BP 401 EP 413 DI 10.1007/s00382-002-0282-4 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 657HA UT WOS:000181659300006 ER PT J AU Chen, B Chao, WC Liu, X AF Chen, B Chao, WC Liu, X TI Enhanced climatic warming in the Tibetan Plateau due to doubling CO2: a model study (vol 20, pg 433, 2003) SO CLIMATE DYNAMICS LA English DT Correction C1 Univ Maryland, GEST Ctr, Baltimore, MD 21201 USA. Chinese Acad Sci, Inst Earth Environm, Xian, Peoples R China. NASA, Goddard Space Flight Ctr, Greenbelt, MD USA. RP Chen, B (reprint author), Univ Maryland, GEST Ctr, Baltimore Cty, Baltimore, MD 21201 USA. NR 1 TC 1 Z9 1 U1 1 U2 3 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0930-7575 J9 CLIM DYNAM JI Clim. Dyn. PD FEB PY 2003 VL 20 IS 4 BP 433 EP 433 DI 10.1007/s0382-002-0308-6 PG 1 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 657HA UT WOS:000181659300009 ER PT J AU Raju, IS Phillips, DR AF Raju, IS Phillips, DR TI Further developments in the MLPG method for beam problems SO CMES-COMPUTER MODELING IN ENGINEERING & SCIENCES LA English DT Article ID GALERKIN METHOD; THIN BEAMS; PLATES AB An accurate and yet simple Meshless Local Petrov-Galerkin (MLPG) formulation for analyzing beam problems is presented. In the formulation, simple weight functions are chosen as test functions as in the conventional MLPG method. Linear test functions are also chosen, leading to a variation of the MLPG method that is computationally efficient compared to the conventional implementation. The MLPG method is evaluated by applying the formulation to a variety of patch tests, thin beam problems, and problems with load discontinuities. The formulation successfully reproduces exact solutions to machine accuracy when higher order power and spline functions are chosen as test functions or when the linear test function is used, and when constructing the trial functions, the order of the basis function is properly balanced by the order of the weight function. For mixed boundary value problems, deflections, slopes, moments, and shear forces are calculated to the same accuracy by the MLPG method without the use of elaborate post-processing techniques. Problems with load discontinuities require special care - when a reasonable number of nodes are used, the method yields very accurate results. C1 NASA, Langley Res Ctr, Lockheed Martin Space Operat, Hampton, VA 23681 USA. RP Raju, IS (reprint author), NASA, Langley Res Ctr, Lockheed Martin Space Operat, Hampton, VA 23681 USA. NR 12 TC 19 Z9 19 U1 0 U2 0 PU TECH SCIENCE PRESS PI ENCINO PA 4924 BALBOA BLVD, # 488, ENCINO, CA 91316 USA SN 1526-1492 J9 CMES-COMP MODEL ENG JI CMES-Comp. Model. Eng. Sci. PD FEB PY 2003 VL 4 IS 1 BP 141 EP 159 PG 19 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications SC Engineering; Mathematics GA 667WG UT WOS:000182257100010 ER PT J AU Ortiz, RM Wade, CE Ortiz, CL AF Ortiz, RM Wade, CE Ortiz, CL TI Body water handling in response to hypertonic-saline induced diuresis in fasting northern elephant seal pups (Mirounga angustirostris) SO COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY A-MOLECULAR & INTEGRATIVE PHYSIOLOGY LA English DT Article DE GFR; kidney; marine mammals; natriuresis; total body water; water reabsorption ID GLOMERULAR-FILTRATION RATE; RENAL-FUNCTION; VASOPRESSIN LEVELS; SODIUM; CONSERVATION; INCREASES; EXCRETION; INFUSION; HUMANS AB During natural fasting conditions in postweaned northern elephant seal (NES) (Mirounga angustirostris) pups, urinary water loss is minimized and percent total body water (TBW) is maintained constant. However, following infusion of hypertonic saline, glomerular filtration rate (GFR) and urine output increased in fasting pups. Therefore, we quantified the magnitude of the hypernatremia-induced diuresis relative to the animal's total body water (TBW) pool and the percentage of filtered water reabsorbed. Following a 24 h control period, naturally fasting NES pups (n = 7) were infused (4 ml min(-1)) with hypertonic saline (16.7%) at a dose of 3 mmol NaCl kg(-1) body mass. Total body water was estimated prior to infusion by tritium dilution, GFR was estimated by standard creatinine clearance, and urine output (V) was measured for 24 h during the control and post infusion periods. Percentage of filtered water reabsorbed was calculated as (1-(V/GFR))x 100. Twenty-four hours following the infusion, GFR (control: 69 +/- 12 ml min(-1) and post-infusion: 118 +/- 19 ml min(-1); mean +/- S.E.) increased 77 +/- 28% above control and the percentage of filtered water reabsorbed was decreased 0.4 +/- 0.1%. The increase in urine output (control: 218 +/- 47 ml d(-1) and post-infusion: 883 +/- 92 ml d(-1)) accounted for 1.7 +/- 0.2% of the pups' TBW The hypematremia-induced diuresis was accompanied by the loss of body water indicating the lack of water retention. Although the 77% increase in GFR was only associated with a 0.4% decrease in the percentage of filtered water reabsorbed, this decrease was significant enough to result in a 4-fold increase in urine output. Despite the observed diuresis, fasting NES pups appear to possess an efficient water recycling mechanism requiring only a small percentage of body water to excrete an excess salt load. This water recycling mechanism may allow pups to avoid negative perturbations in body water as they initiate feeding in a marine environment following the fast. (C) 2002 Elsevier Science Inc. All rights reserved. C1 Univ Calif Santa Cruz, Dept Biol, Santa Cruz, CA 95064 USA. NASA, Ames Res Ctr, Div Life Sci, Moffett Field, CA 94035 USA. RP Ortiz, RM (reprint author), Univ Calif Santa Cruz, Dept Biol, Santa Cruz, CA 95064 USA. NR 23 TC 6 Z9 6 U1 0 U2 4 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 1095-6433 J9 COMP BIOCHEM PHYS A JI Comp. Biochem. Physiol. A-Mol. Integr. Physiol. PD FEB PY 2003 VL 134 IS 2 BP 423 EP 428 AR PII S1095-6433(02)00316-1 DI 10.1016/S1095-6433(02)00316-1 PG 6 WC Biochemistry & Molecular Biology; Physiology; Zoology SC Biochemistry & Molecular Biology; Physiology; Zoology GA 654YX UT WOS:000181525500020 PM 12547272 ER PT J AU Newman, JC James, MA Zerbst, U AF Newman, JC James, MA Zerbst, U TI A review of the CTOA/CTOD fracture criterion SO ENGINEERING FRACTURE MECHANICS LA English DT Article; Proceedings Paper CT Workshop on fundamentals and Applications of the Crack-Tip-Opening-Angle (CTOA) CY APR 23-26, 2001 CL GKSS RES CTR, GEESTHACHT, GERMANY SP NASA Langley Res Ctr HO GKSS RES CTR ID ALUMINUM-ALLOY; CTOA AB The crack-tip-opening angle or displacement (CTOA/CTOD) fracture criterion is one of the oldest fracture criteria applied to fracture of metallic materials with cracks. During the past two decades, the use of elastic-plastic finite-element analyses to simulate fracture of laboratory specimens and structural components using the CTOA criterion has expanded rapidly. But the early applications were restricted to two-dimensional analyses, assuming either plane-stress or plane-strain behavior, which lead to generally non-constant values of CTOA, especially in the early stages of crack extension. Later, the non-constant CTOA values were traced to inappropriate state-of-stress (or constraint) assumptions in the crack-front region and severe crack tunneling in thin-sheet materials. More recently, the CTOA fracture criterion has been used with three-dimensional analyses to study constraint effects, crack tunneling, and the fracture process. The constant CTOA criterion (from crack initiation to failure) has been successfully applied to numerous structural applications, such as aircraft fuselages and pipelines. But why does the "constant CTOA" fracture criterion work so well? This paper reviews the results from several studies, discusses the issues of why CTOA works, and discusses its limitations. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 Mississippi State Univ, Dept Aerosp Engn, Walker Engn Lab, Mississippi State, MS 39762 USA. NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. GKSS Forschungszentrum Geesthacht GmbH, D-2054 Geesthacht, Germany. RP Newman, JC (reprint author), Mississippi State Univ, Dept Aerosp Engn, Walker Engn Lab, 314C,Hardy St, Mississippi State, MS 39762 USA. NR 32 TC 113 Z9 125 U1 6 U2 22 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0013-7944 J9 ENG FRACT MECH JI Eng. Fract. Mech. PD FEB-MAR PY 2003 VL 70 IS 3-4 BP 371 EP 385 AR PII S0013.7944(02)00125-X DI 10.1016/S0013-7944(02)00125-X PG 15 WC Mechanics SC Mechanics GA 625TZ UT WOS:000179832800002 ER PT J AU Ma, L Lam, PW Kokaly, MT Kobayashi, AS AF Ma, L Lam, PW Kokaly, MT Kobayashi, AS TI CTOA of a stable crack in a thin aluminum fracture specimen SO ENGINEERING FRACTURE MECHANICS LA English DT Article; Proceedings Paper CT Workshop on fundamentals and Applications of the Crack-Tip-Opening-Angle (CTOA) CY APR 23-26, 2001 CL GKSS RES CTR, GEESTHACHT, GERMANY SP NASA Langley Res Ctr HO GKSS RES CTR DE stable crack growth; dynamic crack growth; CTOA; COD; Moire interferometry; finite element analysis AB A crack tip opening angle (CTOA) resistance curve was generated from the moire interferometry data of thin single edge notched (SEN) and central notched (CN), 2024-T3 aluminum fracture specimens. This CTOA resistance curve, which has a steady state value of 6degrees, was then used to propagate the cracks in elastic-plastic finite element models of the CN specimen and a CN specimen with a simulated multiple site damage. The CTOA of curved crack growth in a biaxial fracture specimen scattered between 4degrees and 8degrees but the resultant crack tip opening displacement, which is the vector sum of the mode-I and the mode-II crack tip sliding displacement, remained a constant 0.18 mm. The CTOA of a rapidly propagating crack in 1.6 mm. thick, 7075-T6 SEN specimens increased from 4.5degrees at a low-crack velocity to a constant 7degrees at the terminal crack velocity. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 Univ Washington, Dept Mech Engn, Seattle, WA 98195 USA. United Technol Res Ctr, Struct Integr Grp, E Hartford, CT 06108 USA. NASA, Ames Res Ctr, Orbital Sci Corp, Moffett Field, CA 94035 USA. Fatigue Technol Inc, Seattle, WA 98188 USA. RP Kobayashi, AS (reprint author), Univ Washington, Dept Mech Engn, Seattle, WA 98195 USA. NR 18 TC 5 Z9 5 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0013-7944 J9 ENG FRACT MECH JI Eng. Fract. Mech. PD FEB-MAR PY 2003 VL 70 IS 3-4 BP 427 EP 442 AR PII S0013-7944(02)00129-7 DI 10.1016/S0013-7944(02)00129-7 PG 16 WC Mechanics SC Mechanics GA 625TZ UT WOS:000179832800006 ER PT J AU James, MA Newman, JC AF James, MA Newman, JC TI The effect of crack tunneling on crack growth: experiments and CTOA analyses SO ENGINEERING FRACTURE MECHANICS LA English DT Article; Proceedings Paper CT Workshop on fundamentals and Applications of the Crack-Tip-Opening-Angle (CTOA) CY APR 23-26, 2001 CL GKSS RES CTR, GEESTHACHT, GERMANY SP NASA Langley Res Ctr HO GKSS RES CTR DE CTOA; crack growth; unloading compliance; area-average; tunneling; finite-element analysis ID ALUMINUM-ALLOY AB This paper compares experimental crack-front shapes recorded at various stages of crack growth with area-average crack growth values during fracture tests conducted on 2024-T351 aluminum alloy plate. Crack-front shapes were determined by fracturing the specimen to a predetermined amount of crack growth and fatigue cycling the specimen for about 4000 cycles at a high stress ratio (P-min/P-max) to mark the crack-front location. For each shape, the area-average crack length was determined. The evolution of tunneling was used to create a calibration curve that could be used to adjust surface measured crack-length values, for a more representative comparison with analyses that use a straight crack-front approximation. The analysis compares much more favorably with the average crack growth than with the surface measured values near maximum load. However, the area-average technique tends to over correct crack growth near the crack initiation load. Crack tunneling results show that the area-average technique produces more representative crack-length measurements compared to optical based surface measurements. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. Mississippi State Univ, Mississippi State, MS 39762 USA. RP James, MA (reprint author), NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. NR 16 TC 33 Z9 36 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0013-7944 J9 ENG FRACT MECH JI Eng. Fract. Mech. PD FEB-MAR PY 2003 VL 70 IS 3-4 BP 457 EP 468 AR PII S0013-7944(02)00131-5 DI 10.1016/S0013-7944(02)00131-5 PG 12 WC Mechanics SC Mechanics GA 625TZ UT WOS:000179832800008 ER PT J AU Hampton, RW Nelson, D AF Hampton, RW Nelson, D TI Stable crack growth and instability prediction in thin plates and cylinders SO ENGINEERING FRACTURE MECHANICS LA English DT Article; Proceedings Paper CT Workshop on Fundamentals and Applications of the Crack-Tip-Opening-Angle (CTOA) CY APR 23-26, 2001 CL GKSS RES CTR, GEESTHACHT, GERMANY SP NASA Langley Res Ctr HO GKSS RES CTR DE fracture; stable crack growth; CTOA; 3D finite element analysis; 2219-T87 aluminum; thin plates; thin cylinders; tearing resistance; crack tunneling ID MEDIA AB Many fracture applications require accurate prediction of the tearing resistance of thin metallic components. However, the three-dimensional (313) nature of crack front advance is significant even in thin plates and requires special considerations for accurate predictions. An advanced fracture code, WARP3D, was used to model 3D effects and predict the large amounts of crack tearing preceding instability in flat plates and cylinders. In this work, the crack tearing resistance of thin plate aluminum alloy 2219-T87 fracture test specimens was measured experimentally. Finite element analysis (FEA) computations that modeled crack tunneling behavior were performed with WARP3D to determine a characteristic crack tip opening angle to match the observed tearing resistance behavior. Fracture predictions for the same thickness in a pressurized cylinder were then made using the calibrated values, and compared with results from tests and with uniform crack front FEA predictions. The experiments and calculations were performed for two thicknesses of material, the thinner one to verify the methodology, and a thicker one to predict critical crack length for the International Space Station modules. Published by Elsevier Science Ltd. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Stanford Univ, Dept Mech Engn, Design Div, Stanford, CA 94305 USA. RP Hampton, RW (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM rhampton@arc.nasa.gov NR 32 TC 14 Z9 17 U1 0 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0013-7944 EI 1873-7315 J9 ENG FRACT MECH JI Eng. Fract. Mech. PD FEB-MAR PY 2003 VL 70 IS 3-4 BP 469 EP 491 AR PII S0013-7944(02)00132-7 DI 10.1016/S0013-7944(02)00132-7 PG 23 WC Mechanics SC Mechanics GA 625TZ UT WOS:000179832800009 ER PT J AU Newman, JC Dawicke, DS Seshadri, BR AF Newman, JC Dawicke, DS Seshadri, BR TI Residual strength analyses of stiffened and un-stiffened panels - Part I: laboratory specimens SO ENGINEERING FRACTURE MECHANICS LA English DT Article; Proceedings Paper CT Workshop on fundamentals and Applications of the Crack-Tip-Opening-Angle (CTOA) CY APR 23-26, 2001 CL GKSS RES CTR, GEESTHACHT, GERMANY SP NASA Langley Res Ctr HO GKSS RES CTR DE fracture; cracks; CTOA; finite-element method; stiffened panels; aluminum alloy ID ALUMINUM-ALLOY; SHEET; CTOA AB This paper presents the results of residual strength analyses on stiffened and un-stiffened panels using the STructural Analysis of General Shells (STAGS) finite-element shell code and the critical crack-tip-opening angle (CTOA) fracture criterion. Previous analyses of wide, flat panels have shown that high-constraint conditions around a crack front must be modeled in order for the critical CTOA fracture criterion to predict wide panel failures from small laboratory tests. Thus, the STAGS code with the "plane-strain" core option was used in all analyses. In the present study, the critical CTOA (Psi(c)) value and the plane-strain core height were determined from a fit to the experimental load-against-crack-extension results from a series of middle-crack tension specimens (76-1016 mm wide) tested with anti-buckling guides. In the residual strength analyses of the 305-mm wide stiffened panels with a single crack, modeling of the sheet, stiffeners, rivet flexibility and buckling were based on methods and criteria, like that currently used in industry. STAGS and the CTOA criterion were used to predict load-against-crack extension for the single stiffened panels for both intact and cut stiffeners. Analyses were able to predict stable crack growth and residual strength of the single stiffened panels within about +/-5% of the test failure loads. (C) 2002 Elsevier Science Ltd. Aft rights reserved. C1 Mississippi State Univ, Dept Aerosp Engn, Walker Engn Lab 330, Mississippi State, MS 39762 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Old Dominion Univ, Norfolk, VA 23529 USA. RP Newman, JC (reprint author), Mississippi State Univ, Dept Aerosp Engn, Walker Engn Lab 330, Hardy St, Mississippi State, MS 39762 USA. NR 24 TC 10 Z9 12 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0013-7944 J9 ENG FRACT MECH JI Eng. Fract. Mech. PD FEB-MAR PY 2003 VL 70 IS 3-4 BP 493 EP 507 AR PII S0013-7944(02)00133-9 DI 10.1016/S0013-7944(02)00133-9 PG 15 WC Mechanics SC Mechanics GA 625TZ UT WOS:000179832800010 ER PT J AU Seshadri, BR Newman, JC Dawicke, DS AF Seshadri, BR Newman, JC Dawicke, DS TI Residual strength analyses of stiffened and unstiffened panels - Part II: wide panels SO ENGINEERING FRACTURE MECHANICS LA English DT Article; Proceedings Paper CT Workshop on fundamentals and Applications of the Crack-Tip-Opening-Angle (CTOA) CY APR 23-26, 2001 CL GKSS RES CTR, GEESTHACHT, GERMANY SP NASA Langley Res Ctr HO GKSS RES CTR DE crack-tip-opening angle (CTOA); plane-strain core; wide stiffened panels; elastic-plastic finite element analysis AB This paper highlights the results from fracture analyses conducted on the FAA/NASA wide panels (with and without stiffeners) using structural analysis of general shells code and the critical crack-tip-opening angle (CTOA) fracture criterion. The critical CTOA and plane-strain core height values, calibrated from a fit to the experimental load-against-crack-extension results from a series of unstiffened panels (76-1016 turn wide) tests with anti-buckling guides (Part I of this paper), were used in the analyses of wide stiffened and unstiffened panels. As discussed in Part I of this paper, high constraint around the crack front like plane strain has been accounted for by using the "plane-strain core" option in all analyses. By accounting for high constraint around crack front, it was possible for the critical CTOA fracture criterion to predict wide panel failures from small laboratory tests. As followed in Part I of this paper, rivet flexibility and stiffener failures in the analyses of wide panels were based on methods and criteria like that currently used in the in dustry. Analyses were able to predict stable crack growth and residual strength of both stiffened and unstiffened panels with various amounts of multiple-site damage within +/-10% of the test results. Finally, it has been demonstrated that, it is possible to predict the residual strength of wide stiffened and unstiffened panels with critical CTOA calibrated from small laboratory coupons. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 Old Dominion Univ, Norfolk, VA 23529 USA. Mississippi State Univ, Dept Aerosp Engn, Mississippi State, MS 39762 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Seshadri, BR (reprint author), Old Dominion Univ, Norfolk, VA 23529 USA. NR 23 TC 12 Z9 12 U1 1 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0013-7944 J9 ENG FRACT MECH JI Eng. Fract. Mech. PD FEB-MAR PY 2003 VL 70 IS 3-4 BP 509 EP 524 AR PII S0013-7944(02)00134-0 DI 10.1016/S0013-7944(02)00134-0 PG 16 WC Mechanics SC Mechanics GA 625TZ UT WOS:000179832800011 ER PT J AU Qian, H Beard, DA Liang, SD AF Qian, H Beard, DA Liang, SD TI Stoichiometric network theory for nonequilibrium biochemical systems SO EUROPEAN JOURNAL OF BIOCHEMISTRY LA English DT Article DE biochemical network; chemical potential; flux; nonequilibrium thermodynamics; steady-state ID MOTOR PROTEIN KINETICS AB We introduce the basic concepts and develop a theory for nonequilibrium steady-state biochemical systems applicable to analyzing large-scale complex isothermal reaction networks. In terms of the stoichiometric matrix, we demonstrate both Kirchhoff's flux law Sigma(l)J(l) = 0 over a biochemical species, and potential law Sigma(l)mu(l) = 0 over a reaction loop. They reflect mass and energy conservation, respectively. For each reaction, its steady-state flux J can be decomposed into forward and backward one-way fluxes J = J(+) - J(-), with chemical potential difference Deltamu = RT ln(J(-)/J(+)). The product -JDeltamu gives the isothermal heat dissipation rate, which is necessarily non-negative according to the second law of thermodynamics. The stoichiometric network theory (SNT) embodies all of the relevant fundamental physics. Knowing J and Deltamu of a biochemical reaction, a conductance can be computed which directly reflects the level of gene expression for the particular enzyme. For sufficiently small flux a linear relationship between J and Deltamu can be established as the linear flux-force relation in irreversible thermodynamics, analogous to Ohm's law in electrical circuits. C1 Univ Washington, Dept Appl Math, Seattle, WA 98195 USA. Univ Washington, Dept Bioengn, Seattle, WA 98195 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Qian, H (reprint author), Univ Washington, Dept Appl Math, Seattle, WA 98195 USA. FU NCRR NIH HHS [NCRR-1243, NCRR-12609] NR 37 TC 73 Z9 75 U1 1 U2 11 PU BLACKWELL PUBLISHING LTD PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DG, OXON, ENGLAND SN 0014-2956 J9 EUR J BIOCHEM JI Eur. J. Biochem. PD FEB PY 2003 VL 270 IS 3 BP 415 EP 421 DI 10.1046/j.1432-1033.2003.03357.x PG 7 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 638YN UT WOS:000180600700003 PM 12542691 ER PT J AU Kabir, HRH AF Kabir, HRH TI Free vibration response of a three-node shear flexible finite element for moderately deep shells SO FINITE ELEMENTS IN ANALYSIS AND DESIGN LA English DT Article DE three-node element; shells; shear locking; vibration ID REISSNER-MINDLIN PLATE; TRIANGULAR ELEMENT; BENDING ELEMENT; THICK AB A free vibration response of a shear-locking free isoparametric shear flexible three-node triangular finite element suitable for moderately deep shell configurations is presented. The moderately deep shell configuration based on the Sanders' shell theory is incorporated into the element formulation. A shear correction term is introduced in transverse shear strain components to alleviate the shear-locking phenomenon. The element is developed with a full integration scheme. Natural frequencies and mode shapes are obtained and compared for doubly curved shells with the available analytical and finite element solutions. (C) 2002 Elsevier Science B.V. All rights reserved. C1 Kuwait Univ, Dept Civil Engn, Safat 13060, Kuwait. RP Kabir, HRH (reprint author), NASA, USA Solid Rocket Booster Element, Kennedy Space Ctr, FL USA. NR 20 TC 1 Z9 1 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-874X J9 FINITE ELEM ANAL DES JI Finite Elem. Anal. Des. PD FEB PY 2003 VL 39 IS 4 BP 257 EP 281 AR PII S0168-874X(02)00067-7 DI 10.1016/S0168-874X(02)00067-7 PG 25 WC Mathematics, Applied; Mechanics SC Mathematics; Mechanics GA 633JY UT WOS:000180281200001 ER PT J AU Ikegami, M Xu, G Ikeda, K Honma, S Nagaishi, H Dietrich, DL Takeshita, Y AF Ikegami, M Xu, G Ikeda, K Honma, S Nagaishi, H Dietrich, DL Takeshita, Y TI Distinctive combustion stages of single heavy oil droplet under microgravity SO FUEL LA English DT Article DE droplet combustion; temperature history; heavy oil; multicomponent fuel; microgravity; vaporization mechanism ID FUEL OILS; MULTICOMPONENT DROPLETS; COKE AB This report presents an investigation on the combustion of single droplets comprised of heavy oil and oil mixtures blending diesel light oil (LO) and a heavy oil residue (HOR). The tests were conducted in a microgravity facility that offered 10 s of free-fall time. Fine wire thermocouples supported the droplets, resulting in a measurement of droplet temperature history. Additional data were the droplet and flame size history. The results identified four distinctive burning stages between ignition and extinction for heavy oil (C class) and HOR-LO blends. They are, in succession, the start-up, inner evaporation, thermal decomposition (pyrolysis) and polymerization stages. The start-up stage denoted an initial transient period, where the LO components burned from the droplet surface and the droplet temperature increased rapidly. The latter three stages featured pronounced droplet swellings and contractions caused by fuel evaporation and decomposition inside the droplet. An evaporation temperature demarcated the start-up stage from the inner evaporation stage, and this temperature corresponded to a plateau in the temperature history of the droplet. Two additional temperatures, termed the decomposition and polymerization temperatures, indicated the ends of the evaporation and decomposition stages. These temperatures were similarly identified by plateaus or inflection points in the time-temperature diagram. The evaporation temperature gradually decreased with increasing the initial LO mass fraction in the droplet, whereas the other two temperatures were almost independent of the oil composition. All three temperatures increased with decreasing initial droplet diameter, but the dependence was very slight. Based on the results, the combustion of heavy oil droplets appears to be dominated by a distillation-like vaporization mechanism, because of the rapid mass transport within the droplets caused by the disruptive burning. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 Natl Inst Adv Ind Sci & Technol, AIST Hokkaido, Toyohira Ku, Sapporo, Hokkaido 0628517, Japan. NASA, John H Glenn Res Ctr, Cleveland, OH 44135 USA. Japan Space Utilizat Promot Ctr, Shinjuku Ku, Tokyo 1698624, Japan. RP Ikegami, M (reprint author), Natl Inst Adv Ind Sci & Technol, AIST Hokkaido, Toyohira Ku, 2-17 Tsukisamu Higashi, Sapporo, Hokkaido 0628517, Japan. NR 35 TC 11 Z9 11 U1 0 U2 3 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0016-2361 J9 FUEL JI Fuel PD FEB PY 2003 VL 82 IS 3 BP 293 EP 304 AR PII S0016-2361(02)00257-0 DI 10.1016/S0016-2361(02)00257-0 PG 12 WC Energy & Fuels; Engineering, Chemical SC Energy & Fuels; Engineering GA 628ND UT WOS:000180001600006 ER PT J AU Gounelle, M Zolensky, ME Liou, JC Bland, PA Alard, O AF Gounelle, M Zolensky, ME Liou, JC Bland, PA Alard, O TI Mineralogy of carbonaceous chondritic microclasts in howardites: Identification of C2 fossil micrometeorites SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Review ID INTERPLANETARY DUST PARTICLES; ANTARCTIC MICROMETEORITES; AQUEOUS ALTERATION; CI CHONDRITES; SOLAR-SYSTEM; PARENT BODY; ISOTOPE COSMOCHEMISTRY; SIDEROPHILE ELEMENTS; COSMIC SPHERULES; OXYGEN-ISOTOPE AB Seventy-one carbonaceous chondritic microclasts of average size 150 gm have been found in three howardites (Yamato-793497, Jodzie, Kapoeta). All carbonaceous chondritic microclasts are made of a fine-grained phyllosilicate-rich matrix supporting a variety of minerals such as olivine, pyroxene, spinel, iron oxides, iron-nickel sulfides, and calcium carbonates. Such a mineralogy is typical of chondritic C2 matter. Half of the carbonaceous chondritic microclasts are tochilinite-rich, and have been tentatively called CM2 microclasts. The other half are magnetite-rich, and have been tentatively called CR2 microclasts. The absence of a correlation between the CM2/CR2 ratio in carbonaceous chondritic microclasts and in numerous millimeter-sized clasts found in the same sections argues for carbonaceous chondritic microclasts being true micrometeorites rather than fragments of larger objects. Dynamical simulations show that it is possible for asteroidal dust to encounter Vesta (the howardite's putative parent-asteroid) at velocity low enough (<1 km.s(-1)) to prevent fragmentation. Because the micrometeorite flux in the inner Solar System has been decreasing with time, we argue that carbonaceous chondritic microclasts have been trapped in Vesta's regolith early in the history of the Solar System and are fossil micrometeorites. Because both microclasts and clasts found in howardites are related to C2 chondritic matter, we propose that C2 matter represents the bulk, or at least a significant fraction of the primordial howardite parent-asteroid. Considering the abundance of C2 matter among fossil micrometeorites, we speculate that the C2 fossil micrometorites are the so far unidentified agent of the late chondritic veneer that endowed the Earth's mantle with an excess of siderophile elements relative to the contents predicted by the core-mantle separation models. The discovery that C2 fossil micrometeorites are similar to C2 modern Antarctic micrometeorites supports recent models proposing a micrometeoritic origin for the Earth's oceans and volatile species. Copyright (C) 2003 Elsevier Science Ltd. C1 Ctr Spectrometrie Nucl & Spectrometrie Masse, F-91405 Orsay, France. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Lockheed Martin Space Operat, Houston, TX 77058 USA. Open Univ, Planetary & Space Sci Res Inst, Milton Keynes MK7 6AA, Bucks, England. Open Univ, Dept Earth Sci, Milton Keynes MK7 6AA, Bucks, England. RP Gounelle, M (reprint author), Nat Hist Museum, Dept Mineral, London SW7 5BD, England. EM mattg@nhm.ac.uk RI ALARD, Olivier/A-7128-2008 OI ALARD, Olivier/0000-0002-0832-6625 NR 121 TC 57 Z9 57 U1 2 U2 9 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD FEB PY 2003 VL 67 IS 3 BP 507 EP 527 AR PII S0016-7037(02)00985-7 DI 10.1016/S0016-7037(02)00985-7 PG 21 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 640MM UT WOS:000180692600013 ER EF