FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Inagaki, F Okada, H Tsapin, AI Nealson, KH Horikoshi, K AF Inagaki, F Okada, H Tsapin, AI Nealson, KH Horikoshi, K TI Endolithic genetic record of ancient microbes in Cretaceous black shale SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract C1 JAMSTEC, Subground Animalcule Retrieval Project, Yokosuka, Kanagawa 2370061, Japan. Hokkaido Univ, Grad Sch Sci, Div Earth & Planetary Sci, Sapporo, Hokkaido 0600810, Japan. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. EM inagaki@jamstec.go.jp; oka@ep.sci.hokudai.ac.jp; knealson@mail1.jpl.nasa.gov NR 0 TC 0 Z9 0 U1 2 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD AUG PY 2002 VL 66 IS 15A SU 1 BP A354 EP A354 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 583RX UT WOS:000177423400689 ER PT J AU Jones, JH Neal, CR Ely, JC AF Jones, JH Neal, CR Ely, JC TI Highly siderophile elements and planetary accretion SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract C1 NASA JSC, Houston, TX 77058 USA. Univ Notre Dame, Dept Civil Engn & Geol Sci, Notre Dame, IN 46556 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD AUG PY 2002 VL 66 IS 15A SU 1 BP A372 EP A372 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 583RX UT WOS:000177423400723 ER PT J AU Kounaves, SP Hecht, MH AF Kounaves, SP Hecht, MH TI Geochemical analysis on mars SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract C1 Tufts Univ, Dept Chem, Medford, MA 02155 USA. Jet Propuls Lab, Pasadena, CA USA. NR 0 TC 1 Z9 1 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD AUG PY 2002 VL 66 IS 15A SU 1 BP A413 EP A413 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 583RX UT WOS:000177423400804 ER PT J AU Mumma, MJ AF Mumma, MJ TI Chemical diversity among comets: Implications for delivery of water and prebiotic organics to early Earth SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. RI mumma, michael/I-2764-2013 NR 2 TC 0 Z9 0 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD AUG PY 2002 VL 66 IS 15A SU 1 BP A534 EP A534 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 583RX UT WOS:000177423401043 ER PT J AU Musselwhite, DS Jones, JH AF Musselwhite, DS Jones, JH TI Mineral/melt partitioning of Sm, Eu and Gd: implications for the redox state of the Martian mantle SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract ID CRUST; MARS C1 NASA, JSC, ARES Res Off, Houston, TX 77058 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD AUG PY 2002 VL 66 IS 15A SU 1 BP A539 EP A539 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 583RX UT WOS:000177423401053 ER PT J AU Orphan, VJ House, CH Hinrichs, KU McKeegan, KD DeLong, EF AF Orphan, VJ House, CH Hinrichs, KU McKeegan, KD DeLong, EF TI Direct phylogenetic and isotopic evidence for multiple groups of archaea involved in the anaerobic oxidation of methane. SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Penn State Univ, University Pk, PA 16802 USA. Woods Hole Oceanog Inst, Woods Hole, MA 02543 USA. Univ Calif Los Angeles, Los Angeles, CA 90024 USA. Monterey Bay Aquarium Res Inst, Moss Landing, CA USA. RI McKeegan, Kevin/A-4107-2008; Orphan, Victoria/K-1002-2014 OI McKeegan, Kevin/0000-0002-1827-729X; Orphan, Victoria/0000-0002-5374-6178 NR 0 TC 7 Z9 7 U1 1 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD AUG PY 2002 VL 66 IS 15A SU 1 BP A571 EP A571 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 583RX UT WOS:000177423401112 ER PT J AU Peslier, AH Brandon, AD Francis, D Ludden, J AF Peslier, AH Brandon, AD Francis, D Ludden, J TI Melt-rock reaction in Canadian cordillera mantle xenoliths SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract C1 Univ Houston, Texas Ctr Supercond, Houston, TX 77204 USA. NASA, JSC, Houston, TX 77058 USA. McGill Univ, Dept Earth & Planetary Sci, Montreal, PQ H3A 2A7, Canada. Ctr Rech Petrog & Geochim, F-54501 Vandoeuvre Les Nancy, France. RI Peslier, Anne/F-3956-2010 NR 3 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD AUG PY 2002 VL 66 IS 15A SU 1 BP A594 EP A594 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 583RX UT WOS:000177423401158 ER PT J AU Sandford, SA AF Sandford, SA TI Presolar/interstellar materials SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD AUG PY 2002 VL 66 IS 15A SU 1 BP A665 EP A665 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 583RX UT WOS:000177423401299 ER PT J AU Summons, RE Embaye, T Jahnke, LL Baumgartner, M AF Summons, RE Embaye, T Jahnke, LL Baumgartner, M TI New ether lipid biomarkers from a thermophilic methanogen SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract C1 MIT, EAPS Dept, Cambridge, MA 02139 USA. NASA, Moffett Field, CA 94035 USA. Univ Regensburg, LS Mikrobiol, D-93053 Regensburg, Germany. NR 0 TC 0 Z9 0 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD AUG PY 2002 VL 66 IS 15A SU 1 BP A752 EP A752 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 583RX UT WOS:000177423401473 ER PT J AU Toporski, J Steele, A Westall, F Thomas-Keprta, K McKay, DS AF Toporski, J Steele, A Westall, F Thomas-Keprta, K McKay, DS TI Bacterial silicification - an experimental approach SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract C1 Carnegie Inst Washington, Geophys Lab, Washington, DC 20015 USA. CNRS, Ctr Biophys Mol, F-45071 Orleans, France. NASA, JSC, Houston, TX 77058 USA. NR 4 TC 2 Z9 2 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD AUG PY 2002 VL 66 IS 15A SU 1 BP A781 EP A781 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 583RX UT WOS:000177423401528 ER PT J AU Pritchard, ME Simons, M Rosen, PA Hensley, S Webb, FH AF Pritchard, ME Simons, M Rosen, PA Hensley, S Webb, FH TI Co-seismic slip from the 1995 July 30 Mw=8.1 Antofagasta, Chile, earthquake as constrained by InSAR and GPS observations SO GEOPHYSICAL JOURNAL INTERNATIONAL LA English DT Article DE earthquakes; InSAR; inverse theory; northern Chile; subduction zone ID SAN-ANDREAS FAULT; NORTHERN CHILE; RADAR INTERFEROMETRY; SUBDUCTION ZONE; LANDERS EARTHQUAKE; CRUSTAL DEFORMATION; SURFACE DEFORMATION; NAZCA PLATE; CALIFORNIA; INVERSION AB We analyse radar interferometric and GPS observations of the displacement field from the 1995 July 30 M-w = 8.1 Antofagasta, Chile, earthquake and invert for the distribution of slip along the co-seismic fault plane. Using a fixed fault geometry, we compare the use of singular-value decomposition and constrained linear inversion to invert for the slip distribution and find that the latter approach is better resolved and more physically reasonable. Separate inversions using only GPS data, only InSAR data from descending orbits, and InSAR data from both ascending and descending orbits without the GPS data illustrate the complimentary nature of GPS and the presently available InSAR data. The GPS data resolve slip near GPS benchmarks well, while the InSAR provides greater spatial sampling. The combination of ascending and descending InSAR data contributes greatly to the ability of InSAR to resolve the slip model, thereby emphasizing the need to acquire this data for future earthquakes. The rake, distribution of slip and seismic moment of our preferred model are generally consistent with previous seismic and geodetic inversions, although significant differences do exist. GPS data projected in the radar line-of-sight (LOS) and corresponding InSAR pixels have a root mean square (rms) difference of about 3 cm. Comparison of our predictions of vertical displacement and observed uplift from corraline algae have an rms of 10 cm. Our inversion and previous results reveal that the location of slip might be influenced by the 1987 M-w = 7.5 event. Our analysis further reveals that the 1995 slip distribution was affected by a 1988 M-w = 7.2 event, and might have influenced a 1998 M-w = 7.0 earthquake that occurred downdip of the 1995 rupture. Our slip inversion reveals a potential change in mechanism in the southern portion of the rupture, consistent with seismic results. Predictions of the satellite LOS displacement from a seismic inversion and a joint seismic/GPS inversion do not compare favourably with the InSAR observations. C1 CALTECH, Seismol Lab, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Seismol Lab, Div Geol & Planetary Sci, 1200 E Calif Blvd 252-21, Pasadena, CA 91125 USA. EM matt@gps.caltech.edu RI Pritchard, Matthew/L-5892-2015; OI Pritchard, Matthew/0000-0003-3616-3373; Simons, Mark/0000-0003-1412-6395 NR 49 TC 64 Z9 68 U1 1 U2 14 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0956-540X EI 1365-246X J9 GEOPHYS J INT JI Geophys. J. Int. PD AUG PY 2002 VL 150 IS 2 BP 362 EP 376 DI 10.1046/j.1365-246X.2002.01661.x PG 15 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 574ZU UT WOS:000176921500002 ER PT J AU Carr, ME Tang, WQ Liu, WT AF Carr, ME Tang, WQ Liu, WT TI CO2 exchange coefficients from remotely sensed wind speed measurements: SSM/I versus QuikSCAT in 2000 SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ATMOSPHERIC CARBON-DIOXIDE; EQUATORIAL PACIFIC-OCEAN; SEA-SURFACE TEMPERATURE; INTERANNUAL VARIABILITY; MICROWAVE IMAGER; CONSEQUENCES AB We compare here the air-sea exchange coefficient for CO2 estimated with monthly mean wind speed measured by the Special Sensing Microwave Imager (SSM/I), K-S, and by the scatterometer QuikSCAT, K-Q, for the year 2000. K-S and K-Q present the same patterns, although are larger than in similar to65% of the world ocean. Zonal mean K-S are consistently larger, except similar to50degreesS and north of 10degreesS in the Indian Ocean. Global oceanic uptake, F-Q, estimated using K-Q and climatological Deltap(CO2) ranges from 0.43 (July) to 2.6 Gt C y(-1) (December). The global sink estimated from SSM/I is similar to10% larger than F-Q for most of the year. This comparison supports the use of SSM/I to quantify interannual variability of the global exchange coefficient of CO2. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Carr, ME (reprint author), CALTECH, Jet Prop Lab, M-S 300-323,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 18 TC 10 Z9 10 U1 2 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 AUG 1 PY 2002 VL 29 IS 15 AR 1740 DI 10.1029/2002GL015068 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 610MX UT WOS:000178964900014 ER PT J AU Gregg, WW Conkright, ME AF Gregg, WW Conkright, ME TI Decadal changes in global ocean chlorophyll SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB The global ocean chlorophyll archive produced by the CZCS was revised using compatible algorithms with SeaWiFS. Both archives were then blended with in situ data to reduce residual errors. This methodology permitted a quantitative comparison of decadal changes in global ocean chlorophyll from the CZCS (1979-1986) and SeaWiFS (1997-2000) records. Global spatial distributions and seasonal variability of ocean chlorophyll were similar, but global means decreased over the two observational segments. Major changes were observed regionally: chlorophyll concentrations decreased in the northern high latitudes while chlorophyll in the low latitudes increased. Mid-ocean gyres exhibited limited changes. The overall spatial and seasonal similarity of the two data records suggests that the changes are due to natural variability. These results provide evidence of how the Earth's climate may be changing and how ocean biota respond. C1 NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. NOAA, Natl Oceanog Data Ctr, Ocean Climate Lab, Silver Spring, MD 20910 USA. RP NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. EM gregg@cabin.gsfc.nasa.gov; mconkright@nodc.noaa.gov NR 8 TC 69 Z9 70 U1 1 U2 9 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 AUG 1 PY 2002 VL 29 IS 15 AR 1730 DI 10.1029/2002GL014689 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 610MX UT WOS:000178964900023 ER PT J AU Kim, HR von Frese, RRB Kim, JW Taylor, PT Neubert, T AF Kim, HR von Frese, RRB Kim, JW Taylor, PT Neubert, T TI Orsted verifies regional magnetic anomalies of the Antarctic lithosphere SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID FIELD AB [1] Initial magnetic measurements from the Orsted satellite reveal lithospheric anomalies over the Antarctic that are similar to those obtained by Magsat. Accordingly, lithospheric anomalies can be extracted from the Orsted data, despite the much greater operational altitude of Orsted (650- 865 km) relative to Magsat (350- 550 km). Furthermore, these correspondences confirm the lithospheric origins for the resulting small- amplitude anomalies in the satellite data. In studies of the Antarctic lithosphere, the Magsat data particularly were limited by the large relative uncertainties of their lithospheric components. These uncertainties occurred because the short nearly seven- month mission more than 20 years ago collected data over austral high summer and early fall when the contaminating large-amplitude external field effects were at a maximum. Therefore, the recent and more numerous Orsted measurements greatly facilitate our efforts to separate effectively the core, lithospheric, and external field components for enhanced studies of the Antarctic lithosphere. C1 Ohio State Univ, Dept Geol Sci, Columbus, OH 43210 USA. Ohio State Univ, Byrd Polar Res Ctr, Columbus, OH 43210 USA. Sejong Univ, Dept Earth Sci, Seoul 143747, South Korea. NASA, Goddard Space Flight Ctr, Geodynam Branch, Greenbelt, MD 20771 USA. Danish Meteorol Inst, Solar Terr Phys Div, Copenhagen, Denmark. RP Kim, HR (reprint author), Ohio State Univ, Dept Geol Sci, Columbus, OH 43210 USA. RI Taylor, Patrick/D-4707-2012 OI Taylor, Patrick/0000-0002-1212-9384 NR 16 TC 1 Z9 1 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 AUG 1 PY 2002 VL 29 IS 15 AR 1723 DI 10.1029/2001GL013662 PG 3 WC Geosciences, Multidisciplinary SC Geology GA 610MX UT WOS:000178964900030 ER PT J AU Kuang, ZM Margolis, J Toon, G Crisp, D Yung, Y AF Kuang, ZM Margolis, J Toon, G Crisp, D Yung, Y TI Spaceborne measurements of atmospheric CO2 by high-resolution NIR spectrometry of reflected sunlight: An introductory study SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ABSORPTION; O-2 AB [1] We introduce a strategy for measuring the column- averaged CO2 dry air volume mixing ratio X-CO2 from space. It employs high resolution spectra of reflected sunlight taken simultaneously in near- infrared (NIR) CO2 (1.58-mum and 2.06-mum) and O-2 (0.76-mum) bands. Simulation experiments, show that precisions of similar to0.3-2.5 ppmv for X-CO2 can be achieved from individual clear sky soundings for a range of atmospheric/ surface conditions when the scattering optical depth tau(s) is less than similar to0.3. When averaged over many clear sky soundings, random errors become negligible. This high precision facilitates the identification and correction of systematic errors, which are recognized as the most serious impediment for the satellite X-CO2 measurements. We briefly discuss potential sources of systematic errors, and show that some of them may result in geographically varying biases in the measured X-CO2. This highlights the importance of careful calibration and validation measurements, designed to identify and eliminate sources of these biases. We conclude that the 3- band, spectrometric approach using NIR reflected sunlight has the potential for highly accurate X-CO2 measurements. C1 CALTECH, Dept Geol & Planetary Sci, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. RP Kuang, ZM (reprint author), CALTECH, Dept Geol & Planetary Sci, Pasadena, CA 91125 USA. NR 11 TC 58 Z9 61 U1 0 U2 13 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 AUG 1 PY 2002 VL 29 IS 15 AR 1716 DI 10.1029/2001GL014298 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 610MX UT WOS:000178964900037 ER PT J AU Mills, FP Cageao, RP Nemtchinov, V Jiang, Y Sander, SP AF Mills, FP Cageao, RP Nemtchinov, V Jiang, Y Sander, SP TI OH column abundance over Table Mountain Facility, California: Annual average 1997-2000 SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID STRATOSPHERIC OH; MIDDLE ATMOSPHERE; DOPPLER DETECTION; FRITZ PEAK; SPECTROMETER; REGIME AB The column abundance of OH over Table Mountain Facility, California, (TMF) has been measured regularly since July 1997 using the Fourier-transform Ultraviolet Spectrometer. The annual average OH column observed for 1998-2000 is 10-20% larger than that observed by another group over Tokyo for 1992-1995; 30-65% smaller than that observed by other groups over Colorado and New Mexico for 1980-1996; and 15-30% smaller than calculated by photochemical models. The Tokyo annual average and model estimates are within the range of geophysical variability for the OH column observed over TMF but the Colorado and New Mexico annual averages are not. This suggests the possibility of systematic errors in one or more of the data sets. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Mills, FP (reprint author), CALTECH, Jet Prop Lab, 183-901,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 16 TC 7 Z9 7 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 AUG 1 PY 2002 VL 29 IS 15 AR 1742 DI 10.1029/2001GL014151 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 610MX UT WOS:000178964900012 ER PT J AU Rastatter, L Hesse, M Kuznetsova, M Gombosi, TI DeZeeuw, DL AF Rastatter, L Hesse, M Kuznetsova, M Gombosi, TI DeZeeuw, DL TI Magnetic field topology during July 14-16 2000 (Bastille Day) solar CME event SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID GLOBAL MAGNETOHYDRODYNAMIC SIMULATIONS; ITERATIVE MAPPING PROCEDURE; LAW BOUNDARY-CONDITION; IMPLEMENTATION AB The July 14-16, 2000 (Bastille Day) event was marked by an extraordinary level of geomagnetic activity following the impact of a large magnetic cloud onto the Earth's magnetosphere at 14:38 on July 15, 2000. The strong increase of the solar wind speed, and density and the large amplitude and variability of B-y and B-z gives rise to dramatic topological changes of unexpected magnitude in the magnetic field of the near-Earth magnetosphere. This event is one of the first real events comprehensively modeled with the adaptive grid MHD simulation scheme BATS-R-US. Magnetic field line integrations were performed with the model output to obtain the three-dimensional magnetic topology and the magnetic mapping between the northern and the southern hemisphere of the Earth. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Michigan, Dept Engn, Ann Arbor, MI 48109 USA. RP Rastatter, L (reprint author), NASA, Goddard Space Flight Ctr, Code 696, Greenbelt, MD 20771 USA. RI De Zeeuw, Darren/F-3667-2011; Hesse, Michael/D-2031-2012; Rastaetter, Lutz/D-4715-2012; Kuznetsova, Maria/F-6840-2012; Gombosi, Tamas/G-4238-2011 OI Rastaetter, Lutz/0000-0002-7343-4147; Gombosi, Tamas/0000-0001-9360-4951 NR 13 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 AUG 1 PY 2002 VL 29 IS 15 AR 1747 DI 10.1029/2001GL014136 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 610MX UT WOS:000178964900007 ER PT J AU Lobell, DB Hicke, JA Asner, GP Field, CB Tucker, CJ Los, SO AF Lobell, DB Hicke, JA Asner, GP Field, CB Tucker, CJ Los, SO TI Satellite estimates of productivity and light use efficiency in United States agriculture, 1982-98 SO GLOBAL CHANGE BIOLOGY LA English DT Article DE agriculture; carbon; corn; light-use efficiency; net primary production; wheat ID RADIATION-USE EFFICIENCY; NET PRIMARY PRODUCTION; TERRESTRIAL CARBON STORAGE; GROSS PHOTOSYNTHESIS; SOLAR-RADIATION; WINTER-WHEAT; YIELD; NITROGEN; CLIMATE; INDEX AB Remote sensing of net primary production (NPP) is a critical tool for assessing spatial and temporal patterns of carbon exchange between the atmosphere and biosphere. However, satellite estimates suffer from a lack of large-scale field data needed for validation, as well as the need to parameterize plant light-use efficiencies (LUEs). In this study, we estimated cropland NPP with the Carnegie-Ames-Stanford-Approach (CASA), a biogeochemical model driven by satellite observations, and then compared these results with field estimates based on harvest data from United States Department of Agriculture National Agriculture Statistics Service (NASS) county statistics. Observed interannual variations in NPP over a 17-year period were well modelled by CASA, with exceptions mainly due to occasional difficulties in estimating NPP from harvest yields. The role of environmental stressors in agriculture was investigated by running CASA with and without temperature and moisture down-regulators, which are used in the model to simulate climate impacts on plant LUE. In most cases, correlations with NASS data were highest with modelled stresses, while the opposite was true for irrigated and temperature resistant crops. Analysis of the spatial variability in computed LUE revealed significantly higher values for corn than for other crops, suggesting a simple parameterization of LUE for future studies based on the fraction of area with corn. Absolute values of LUE were much lower than those reported in field trials, due to uncommonly high yields in most field trials, as well as overestimates of absorbed radiation in CASA attributed to bias from temporal compositing of satellite data. Total NPP for US croplands, excluding Alaska and Hawaii, was estimated as 0.62 Pg C year(-1) , representing similar to20% of total US NPP, and exhibited a positive trend of 3.7 Tg C year(-2) . These results have several implications for large-scale carbon cycle research that are discussed, and are especially relevant for studies of the role of agriculture in the global carbon balance. C1 Univ Colorado, Dept Geol Sci, Boulder, CO 80309 USA. Univ Colorado, Environm Studies Program, Boulder, CO 80309 USA. Carnegie Inst Washington, Dept Global Ecol, Stanford, CA 94305 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Coll Swansea, Dept Geog, Swansea, W Glam, Wales. RP Lobell, DB (reprint author), Univ Colorado, Dept Geol Sci, Campus Box 399,Benson Earth Sci Bldg, Boulder, CO 80309 USA. EM david.lobell@colorado.edu RI Los, Sietse/G-8985-2012; Hicke, Jeff/M-9677-2013; Asner, Gregory/G-9268-2013; OI Asner, Gregory/0000-0001-7893-6421; Los, Sietse/0000-0002-1325-3555 NR 68 TC 110 Z9 150 U1 4 U2 60 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 1354-1013 J9 GLOBAL CHANGE BIOL JI Glob. Change Biol. PD AUG PY 2002 VL 8 IS 8 BP 722 EP 735 DI 10.1046/j.1365-2486.2002.00503.x PG 14 WC Biodiversity Conservation; Ecology; Environmental Sciences SC Biodiversity & Conservation; Environmental Sciences & Ecology GA 572WR UT WOS:000176798400003 ER PT J AU Raich, JW Potter, CS Bhagawati, D AF Raich, JW Potter, CS Bhagawati, D TI Interannual variability in global soil respiration, 1980-94 SO GLOBAL CHANGE BIOLOGY LA English DT Article DE climate change; global carbon cycle; global warming; model; soil carbon dioxide emissions ID ATMOSPHERIC CARBON-DIOXIDE; NET PRIMARY PRODUCTIVITY; FOREST FLOOR; TERRESTRIAL ECOSYSTEMS; TALLGRASS PRAIRIE; EUROPEAN FORESTS; ORGANIC-CARBON; BOREAL FOREST; WATER CONTENT; CO2 FLUXES AB We used a climate-driven regression model to develop spatially resolved estimates of soil-CO2 emissions from the terrestrial land surface for each month from January 1980 to December 1994, to evaluate the effects of interannual variations in climate on global soil-to-atmosphere CO2 fluxes. The mean annual global soil-CO2 flux over this 15-y period was estimated to be 80.4 (range 79.3-81.8) Pg C. Monthly variations in global soil-CO2 emissions followed closely the mean temperature cycle of the Northern Hemisphere. Globally, soil-CO2 emissions reached their minima in February and peaked in July and August. Tropical and subtropical evergreen broad-leaved forests contributed more soil-derived CO2 to the atmosphere than did any other vegetation type (similar to30% of the total) and exhibited a biannual cycle in their emissions. Soil-CO2 emissions in other biomes exhibited a single annual cycle that paralleled the seasonal temperature cycle. Interannual variability in estimated global soil-CO2 production is substantially less than is variability in net carbon uptake by plants (i.e., net primary productivity). Thus, soils appear to buffer atmospheric CO2 concentrations against far more dramatic seasonal and interannual differences in plant growth. Within seasonally dry biomes (savannas, bushlands and deserts), interannual variability in soil-CO2 emissions correlated significantly with interannual differences in precipitation. At the global scale, however, annual soil-CO2 fluxes correlated with mean annual temperature, with a slope of 3.3 Pg C y(-1) per degreesC. Although the distribution of precipitation influences seasonal and spatial patterns of soil-CO2 emissions, global warming is likely to stimulate CO2 emissions from soils. C1 Iowa State Univ, Dept Bot, Ames, IA 50011 USA. NASA, Ecosyst Sci & Technol Branch, Ames Res Ctr, Moffett Field, CA 94035 USA. Iowa State Univ, Dept Civil & Construct Engn, Ames, IA 50011 USA. RP Raich, JW (reprint author), Iowa State Univ, Dept Bot, 353 Bessey Hall, Ames, IA 50011 USA. RI Smorkalov, Ivan/B-6422-2014 NR 65 TC 323 Z9 416 U1 4 U2 105 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 AUG PY 2002 VL 8 IS 8 BP 800 EP 812 DI 10.1046/j.1365-2486.2002.00511.x PG 13 WC Biodiversity Conservation; Ecology; Environmental Sciences SC Biodiversity & Conservation; Environmental Sciences & Ecology GA 572WR UT WOS:000176798400008 ER PT J AU Jenkins, JM Kolodner, MA Butler, BJ Suleiman, SH Steffes, PG AF Jenkins, JM Kolodner, MA Butler, BJ Suleiman, SH Steffes, PG TI Microwave remote sensing of the temperature and distribution of sulfur compounds in the lower atmosphere of Venus SO ICARUS LA English DT Article DE Venus; atmosphere; atmospheres; composition; structure; radio observations; radiative transfer ID RADIO OCCULTATION; PROFILES; CLOUD; ABSORPTION; MAGELLAN; CIRCULATION; ABUNDANCE; DIOXIDE; SURFACE; SYSTEM AB A multi-wavelength radio frequency observation of Venus was performed on April 5, 1996, with the Very Large Array to investigate potential variations in the vertical and horizontal distribution of temperature and the sulfur compounds sulfur dioxide (SO2) and sulfuric acid vapor (H2SO4(g)) in the atmosphere of the planet. Brightness temperature maps were produced which feature significantly darkened polar regions compared to the brighter low-latitude regions at both observed frequencies. This is the first time such polar features have been seen unambiguously in radio wavelength observations of Venus. The limb-darkening displayed in the maps helps to constrain the vertical profile Of H2SO4(g), temperature, and to some degree SO2. The maps were interpreted by applying a retrieval algorithm to produce vertical profiles of temperature and abundance of H2SO4(g) given an assumed sub-cloud abundance Of SO2. The results indicate a substantially higher abundance of H2SO4(g) at high latitudes (above 45degrees) than in the low-latitude regions. The retrieved temperature profiles are up to 25 K warmer than the profile obtained by the Pioneer Venus sounder probe at altitudes below 40 km (depending on location and assumed SO2 abundance). For 150 ppm Of SO2, it is more consistent with the temperature profile obtained by Mariner 5, extrapolated to the surface via a dry adiabat. The profiles obtained for H2SO4(g) at high latitudes are consistent with those derived from the Magellan radio occultation experiments, peaking at around 8 ppm at an altitude of 46 km and decaying rapidly away from that altitude. At low latitudes, no significant H2SO4(g) is observed, regardless of the assumed SO2 content. This is well below that measured by Mariner 10 (Lipa and Tyler 1979, Icarus 39,192-208), which peaked at similar to14 ppm near 47 km. Our results favor less than or equal to100 ppm Of SO2 at low latitudes and less than or equal to50 ppm in polar regions. The low-latitude value is statistically consistent with the results of Bezard et al. (1983, Geophs. Res. Lett. 20, 1587-1590), who found that a. sub-cloud SO2 abundance of 130 +/- 40 ppm best matched their observations in the near-IR. The retrieved temperature profile and higher abundance of H2SO4(g) in polar regions are consistent with a strong equatorial-to-polar, cloud-level flow due to a Hadley cell in the atmosphere of Venus. (C) 2002 Elsevier Science (USA). C1 NASA, Ames Res Ctr, SETI, Moffett Field, CA 94035 USA. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. Natl Radio Astron Observ, Socorro, NM 87801 USA. TRW Co Inc, Redondo Beach, CA 90278 USA. Georgia Inst Technol, Sch Elect & Comp Engn, Atlanta, GA 30332 USA. RP Jenkins, JM (reprint author), NASA, Ames Res Ctr, SETI, MS 245-3, Moffett Field, CA 94035 USA. NR 48 TC 14 Z9 15 U1 0 U2 5 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD AUG PY 2002 VL 158 IS 2 BP 312 EP 328 DI 10.1006/icar.2002.6894 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 592ZK UT WOS:000177966600004 ER PT J AU Hahn, JM Zook, HA Cooper, B Sunkara, B AF Hahn, JM Zook, HA Cooper, B Sunkara, B TI Clementine observations of the zodiacal light and the dust content of the inner solar system SO ICARUS LA English DT Article DE interplanetary dust; zodiacal light ID KUIPER-BELT; CLOUD; COMETS; BANDS; ORIGIN AB Using the Moon to occult the Sun, the Clementine spacecraft used its navigation cameras to map the inner zodiacal light at optical wavelengths over elongations of 3 less than or similar to is an element of less than or similar to 30degrees from the Sun. This surface brightness map is then used to infer the spatial distribution of interplanetary dust over heliocentric distances of about 10 solar radii to the orbit of Venus. The averaged ecliptic surface brightness of the zodiacal light falls off as Z(is an element of) proportional to is an element of(-2.45+/-0.05), which suggests that the dust cross-sectional density nominally falls off as sigma(r) proportional to r(-1.45+/-0.05). The interplanetary dust also has an albedo of a similar or equal to 0.1 that is uncertain by a factor of similar to2. Asymmetries of similar to10% are seen in directions east-west and north-south of the Sun, and these may be due the giant planets' secular gravitational perturbations. We apply a simple model that attributes the zodiacal light as due to three dust populations having distinct inclination distributions, namely, dust from asteroids and Jupiter-family comets (JFCs) having characteristic inclinations of i similar to 7degrees, dust from Halley-type comets having i similar to 33degrees, and an isotropic cloud of dust from Oort Cloud comets. The best-fitting scenario indicates that asteroids + JFCs are the source of about 45% of the optical dust cross section seen in the ecliptic at I AU but that at least 89% of the dust cross section enclosed by a 1-AU-radius sphere is of a cometary origin. Each population's radial density variations can also deviate somewhat from the nominal sigma(r) proportional to r(-1.45). When these results are extrapolated out to the asteroid belt, we find an upper limit on the mass of the light-reflecting asteroidal dust that is equivalent to a 12-km asteroid, and a similar extrapolation of the isotropic dust cloud out to Oort Cloud distances yields a mass equivalent to a I 30-km comet, although the latter mass is uncertain by orders of magnitude. (C) 2002 Elsevier Science (USA). C1 Lunar & Planetary Inst, Houston, TX 77058 USA. NASA, Johnson Space Ctr, Houston, TX 77058 USA. Oceaneering Space Syst, Houston, TX 77058 USA. RP Hahn, JM (reprint author), Lunar & Planetary Inst, 3600 Bay Area Blvd, Houston, TX 77058 USA. NR 36 TC 36 Z9 36 U1 3 U2 6 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD AUG PY 2002 VL 158 IS 2 BP 360 EP 378 DI 10.1006/icar.2002.6881 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 592ZK UT WOS:000177966600007 ER PT J AU Benner, LAM Ostro, SJ Hudson, RS Rosema, KD Jurgens, RF Yeomans, DK Campbell, DB Chandler, JF Shapiro, II AF Benner, LAM Ostro, SJ Hudson, RS Rosema, KD Jurgens, RF Yeomans, DK Campbell, DB Chandler, JF Shapiro, II TI Radar observations of asteroid 3908 Nyx SO ICARUS LA English DT Article DE asteroids; radar ID SHAPE; INVERSION; DISCOVERY AB We report Doppler-only (cw) radar observations of basaltic near-Earth asteroid 3908 Nyx obtained at Arecibo and Goldstone in September and October of 1988. The circular polarization ratio of 0.75 +/- 0.03 exceeds similar to90% of those reported among radar-detected near-Earth asteroids and it implies an extremely rough near-surface at centimeter-to-decimeter spatial scales. Echo power spectra over narrow longitudinal intervals show a central dip indicative of at least one significant concavity. Inversion of cw spectra yields two statistically indistinguishable shape models that have similar shapes and dimensions but pole directions that differ by similar to100degrees. We adopt one as our working model and explore its implications. It has an effective diameter of 1.0 +/- 0.15 km and radar and visual geometric albedos of 0.15 +/- 0.075 and 0.16(-0.05)(+0.08). The visual albedo supports the interpretation by D. P. Cruikshank et al. (1991, Icarus 89, 1-13) that Nyx has a thermal inertia consistent with that of bare rock. The model is irregular, modestly asymmetric, and topographically rugged. (C) 2002 Elsevier Science (USA). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Washington State Univ, Sch Elect Engn & Comp Sci, Pullman, WA 99164 USA. Cornell Univ, Natl Astron & Ionosphere Ctr, Ithaca, NY 14853 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Benner, LAM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 22 TC 15 Z9 15 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 AUG PY 2002 VL 158 IS 2 BP 379 EP 388 DI 10.1006/icar.2002.6869 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 592ZK UT WOS:000177966600008 ER PT J AU Friedson, AJ Wong, AS Yung, YL AF Friedson, AJ Wong, AS Yung, YL TI Models for polar haze formation in Jupiter's stratosphere SO ICARUS LA English DT Article DE Jupiter; atmosphere; photochemistry; aurorae ID POLYCYCLIC AROMATIC-HYDROCARBONS; PARTICLE FORMATION; HETEROGENEOUS NUCLEATION; INFRARED-SPECTROSCOPY; AGGREGATE PARTICLES; UPPER-ATMOSPHERE; ULTRAVIOLET; SIMULATION; AEROSOLS; NAPHTHALENE AB We present coupled chemical-microphysical models for the formation, growth, and physical properties of the jovian polar haze based on a gas-phase photochemical model for the auroral regions developed by A. S. Wong et al. (2000, Astrophys. J.534, L215-217). In this model, auroral particle precipitation provides an important energy source for enhanced decomposition of methane and production of benzene and polycyclic aromatic hydrocarbons (PAHs). We find that at high altitude, A(4) (pyrene, a hydrocarbon consisting of four fused aromatic rings) should homogeneously nucleate to form tiny primary particles. At lower altitudes, A(3) (phenanthrene) and A(3) (naphthalene) heterogeneously nucleate on the A(4) nuclei. These particles subsequently grow by additional condensation of A(2) on the nucleated particles and by coagulation and eventually sediment out to the troposphere. We run different cases of the aerosol microphysical model for different assumptions regarding the fractal dimension of aggregate particles formed by the coagulation process. If coagulation is assumed to produce spherical particles (of dimensionality 3), then their mean radius at altitudes below the 20-mbar pressure level is computed to be approximately 0.1 mum. If coagulation produces fractal aggregates of dimension 2.1, then their equivalent mean radius below the 20-mbar level is much larger, of order 0.7 mum. Aggregates with fractal dimensions between 2.1 and 3 form with equivalent mean radii between 0.1 and 0.7 mum. In every case, mean particle radius is found to decrease with increasing altitude, as expected for a system approximately in sedimentation-coagulation equilibrium. The predicted range of altitudes where aerosol formation occurs and the mean size to which particles grow are found to be generally consistent with observations. However, our calculations cannot presently account for the large amount of total aerosol loading inferred by M. G. Tomasko et al. (1986, Icarus 65, 218-243). We suggest that the primarily neutral chemical pathway to heavy hydrocarbon and PAH formation proposed by Wong et al. (2000) may proceed too slowly to produce a sufficient amount of condensible material. Inclusion of ion and ion-neutral reactions in the chemical scheme could potentially lead to the prediction of 389 higher PAH production rates, higher nucleation rates, and greater aerosol loading, producing better agreement with the observations. (C) 2002 Elsevier Science (USA). C1 CALTECH, Jet Prop Lab, Div Earth & Space Sci, Pasadena, CA 91109 USA. CALTECH, Dept Geol & Planetary Sci, Pasadena, CA 91125 USA. RP Friedson, AJ (reprint author), CALTECH, Jet Prop Lab, Div Earth & Space Sci, MS 169-237, Pasadena, CA 91109 USA. NR 43 TC 36 Z9 36 U1 1 U2 4 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD AUG PY 2002 VL 158 IS 2 BP 389 EP 400 DI 10.1006/icar.2002.6885 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 592ZK UT WOS:000177966600009 ER PT J AU Magalhaes, JA Seiff, A Young, RE AF Magalhaes, JA Seiff, A Young, RE TI The stratification of Jupiter's troposphere at the Galileo probe entry site SO ICARUS LA English DT Article DE atmospheres; structure; atmospheres; dynamics; Jupiter; atmosphere ID PARA-HYDROGEN; COMET SHOEMAKER-LEVY-9; OUTER PLANETS; GRAVITY-WAVES; ATMOSPHERE; CONVERSION AB Galileo Probe Atmospheric Structure Investigation (ASI) pressure and temperature sensor data acquired during the parachute descent phase have been used to derive the static stability structure of Jupiter's troposphere at pressure levels of 0.5-22 bars using three techniques. The first approach utilizes both the p-sensor and T-sensor data, but since the p-sensor's zero offset was significantly affected by the thermal anomaly in the probe, two other approaches using only T-sensor data have also been developed. By making the physically reasonable assumptions of equilibrium descent for the probe and hydrostatic balance of the atmosphere, an algorithm for deriving the background static stability from T-sensor measurements alone is developed. Regions with static stability 0.1-0.2 K km(-1) are found at 0.5-1.7 bars, 3-8.5 bars, and 14-20 bars. Between these layers, regions of weaker static stability are present. Mean molecular weight gradients due to the vertical variation of water vapor abundance near the 11-bar pressure level appear to stabilize the atmosphere at this level. Oscillatory structures with vertical wavelength similar to15-30 km and amplitude similar to0.1-0.2 K are observed in the T-sensor data. For pressure <2 bars, these eddies are well above the noise level of the measurements and are consistent with the predictions of linear gravity wave theory for a wave with horizontal phase speed c(x) = 160 m s(-1) with respect to System III propagating through the static stability derived from the T-sensor data alone. They provide quantitative confirmation of the static stability derived from T-sensor data in the troposphere where p < 2 bars. The observed static stability structure shows an inverse correlation with the regions of wind shear observed by the Doppler Wind Experiment: regions of highest shear in the horizontal wind appear to be associated with regions of lowest static stability. The particulate population detected by other experiments on the probe shows some correlation with the uppermost layer of static stability, suggesting enhanced solar energy deposition at these levels may play a role in producing the positive static stability. (C) 2002 Elsevier Science (USA). C1 NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. RP Magalhaes, JA (reprint author), NASA, Ames Res Ctr, Div Space Sci, Mail Stop 245-3, Moffett Field, CA 94035 USA. NR 49 TC 27 Z9 27 U1 0 U2 4 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD AUG PY 2002 VL 158 IS 2 BP 410 EP 433 DI 10.1006/icar.2002.6891 PG 24 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 592ZK UT WOS:000177966600011 ER PT J AU Doute, S Lopes, R Kamp, LW Carlson, R Schmitt, B AF Doute, S Lopes, R Kamp, LW Carlson, R Schmitt, B CA Galileo NIMS Team TI Dynamics and evolution of SO2 gas condensation around prometheus-like volcanic plumes on Io as seen by the near infrared mapping spectrometer SO ICARUS LA English DT Article DE satellites of Jupiter; Io; infrared observations; ices; volcanism ID HYPERSPECTRAL IMAGES; GLOBAL DISTRIBUTION; THERMAL EMISSION; ACTIVE VOLCANISM; GALILEO; SURFACE; ATMOSPHERE; MODEL; NIMS; IDENTIFICATION AB We analyze a series of spectral image cubes acquired by the Galileo Near Infrared Mapping Spectrometer (NIMS) over the Prometheus region of to. We use SO2 frost, a volatile compound ubiquitous on the surface, as a tracer to understand various thermodynamic and volcanic processes acting in this equatorial region. Here we develop a new method to derive, from the 12-wavelength NIMS products, the distribution and physical properties of solid SO2. This method is based on the inversion of a bidirectional reflectance model on two observed spectral ratios sensitive to (1) the areal abundance of SO2 and (2) its mean grain size. As a result, reliable and consistent maps of SO2 abundance and granularity are obtained which can be correlated to distinguish four different physical units. The distribution of these SO2 units indicates zones of condensation, metamorphism, and sublimation linked with the thermodynamic and volcanic processes of interest. Our maps depict equatorial plains undisturbed by any kind of vigorous volcanic activity over 35-40% of their surface. Elsewhere, 10-20% of the equatorial plains display abnormally low frost coverage which may imply the recent presence of positive thermal anomalies with temperatures in the range 110-200 K. Hot-spots such as Prometheus, Culann, Surya, and Tupan (to mention the most persistent) emit a great variety of gases, some of which will condense at Io's surface near their source regions. Associated fields of freshly condensed SO2 are easily observed, and deposits of more refractory compounds with higher (e.g., S-8) or lower (e.g., NaCl) molecular weight must also be present (although their exact nature is unknown). Three different mechanisms of emission are proposed for the volatile compounds and supported by the distribution maps. These are (a) the interaction between flowing lava and preexisting volatile deposits on the surface, (b) direct degassing from the lava, and (c) the eruption of a liquid aquifer from underground. The geometric elongation of the Prometheus SO2 deposition ring being related to the development of a 95-km-long lava field is the best illustration of mechanism (a). Details of the progressive emplacement of the SO2 ring by the associated plume are examined by the development of a semiempirical model of material deposition based on a ballistic transfer from the sources to the surface. This model shows that lava emission may have been occuring at Prometheus at a fairly constant rate since Voyager. Mechanism (b) may operate at the hot-spot Surya, which presents a noticeable field of fresh SO2 frost but no extended lava flow. Finally, we have noted on the northwestern flank of the volcanic edifice Emakong the existence of an extremely deep nu(1) + nu(3) SO2 absorption which is indicative of abundant, pure, and perhaps icy SO2 deposits. These could be the result of the eruption of an SO2 liquid aquifer (mechanism (c)). (C) 2002 Elsevier Science (USA). C1 Lab Planetol Grenoble, F-38041 Grenoble 9, France. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Doute, S (reprint author), Lab Planetol Grenoble, Bat D Phys,BP 53, F-38041 Grenoble 9, France. RI Schmitt, Bernard/A-1064-2009; Lopes, Rosaly/D-1608-2016 OI Schmitt, Bernard/0000-0002-1230-6627; Lopes, Rosaly/0000-0002-7928-3167 NR 53 TC 18 Z9 18 U1 0 U2 4 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD AUG PY 2002 VL 158 IS 2 BP 460 EP 482 DI 10.1006/icar.2002.6889 PG 23 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 592ZK UT WOS:000177966600014 ER PT J AU Mosqueira, I Estrada, PR AF Mosqueira, I Estrada, PR TI Apse alignment of the Uranian rings SO ICARUS LA English DT Article DE planetary rings; Uranus; ring dynamics; shepherd satellites; celestial dynamics ID DENSE PLANETARY RINGS; LOCAL SIMULATIONS; SATURNS RINGS; DYNAMICS; SYSTEMS; MODEL AB An explanation of the dynamical mechanism for apse alignment of the eccentric uranian rings is necessary before observations can be used to determine properties such as ring masses, particle sizes, and elasticities. The leading model (P. Goldreich and S. Tremaine 1979, Astron J. 84, 1638-1641) relies on the ring self-gravity to accomplish this task, yet it yields equilibrium masses which are not in accord with Voyager radio measurements. We explore possible solutions such that the self-gravity and the collisional terms are both involved in the process of apse alignment. We consider limits that correspond to a hot and a cold ring, and we show that pressure terms may play a significant role in the equilibrium conditions for the narrow uranian rings. In the cold ring case, where the scale height of the ring near periapse is comparable to the ring particle size, we introduce a new pressure correction pertaining to a region of the ring where the particles are locked in their relative positions and jammed against their neighbors and the velocity dispersion is so low that the collisions are nearly elastic. In this case, we find a solution such that the ring self-gravity maintains apse alignment against both differential precession (m = 1 mode) and the fluid pressure. We apply this model to the uranian alpha ring and show that, compared to the previous self-gravity model, the mass estimate for this ring increases by an order of magnitude. In the case of a hot ring, where the scale height can reach a value as much as 50 times the particle size, we find velocity dispersion profiles that result in pressure forces which act in such a way as to alter the ring equilibrium conditions, again leading to a ring mass increase of an order of magnitude. We find that such a velocity dispersion profile would require a different mechanism than is currently envisioned for establishing a heating/cooling balance in a finite-sized, inelastic particle ring. Finally, we introduce an important correction to the model of E. I. Chiang and P. Goldreich (2000, Astrophys. J. 540, 1084-1090.). These authors relied on collisional forces in the last similar to100 m of an similar to10 km wide ring to increase ring equilibrium masses by up to a factor of similar to100. However, their treatment of ring edges as one-sided surface density drops leads to a strong dependence of the ring mass on the adjustable parameter lambda (the length scale over which the ring's optical depth drops from order unity to zero at the edge). A treatment of the ring edges that takes into account their ridgelike structure retains the increase of ring mass of the order of similar to100 for a 10 km wide ring, while exhibiting weak dependence on X. We conclude that a modified Chiang-Goldreich model can likely account for the masses of narrow, eccentric planetary rings; however, the role of shepherd satellites both in forming ring edges and in altering the streamline precession conditions near them needs to be explored further. It is also unclear whether a fully self-consistent ring model allows for the possibility of rings with negative eccentricity gradients. (C) 2002 Elsevier Science (USA). C1 NASA, Ames SETI Inst, Moffett Field, CA 94035 USA. Cornell Univ, Dept Astron, Ithaca, NY 14850 USA. RP Mosqueira, I (reprint author), NASA, Ames SETI Inst, Mail Stop 245-3, Moffett Field, CA 94035 USA. NR 23 TC 9 Z9 9 U1 0 U2 1 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD AUG PY 2002 VL 158 IS 2 BP 545 EP 556 DI 10.1006/icar.2002.6878 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 592ZK UT WOS:000177966600019 ER PT J AU Yuchnovicz, DE Williams, LJ DiCarlo, DJ AF Yuchnovicz, DE Williams, LJ DiCarlo, DJ TI The digital information facility SO IEEE AEROSPACE AND ELECTRONIC SYSTEMS MAGAZINE LA English DT Article AB The acceptance and implementation of advanced digital avionics and flight control systems is dependent on the successful integration of these systems into the current and future National Airspace System (NAS). This paper describes a digital avionics systems research facility known as the Digital Information Facility (DIF) developed to provide researchers with the ground systems and air-to-ground interfaces needed to conduct and document experiments involving a mix of new technologies within the existing NAS infrastructure. The DIF supports four NAS functions: Controller Pilot Data Link Communications (CPDLC), Flight Information Services (FIS), Differential Global Positioning System (DGPS) navigation, and Automatic Dependent Surveillance-Broadcast (ADS-B). The DIF also includes the capability to record pilot and air traffic management interactions and document research participant observations. The main DIF site is located at NASA's Langley Research Center (LaRC) in Hampton, Virginia. Transportable DIF stations allow additional ground sites to be integrated with the LaRC site to expand geographic coverage and provide a multi-site environment for research experiments and demonstrations. The DIF capability includes connectivity to flight test and simulated aircraft in a fully immersive Communications, Navigation, and Surveillance (CNS) environment. Simulated aircraft provide researchers with a method to perform initial tests prior to flight. In addition, simulated aircraft interacting with live aircraft can provide for a safer means to perform difficult experiments where the margin of safety may be less than acceptable when multiple live aircraft are used. Also highlighted is the status of research projects currently being conducted as part of NASA's Small Aircraft Transportation System (SATS) Program. C1 Res Triangle Inst, Hampton, VA 23681 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Yuchnovicz, DE (reprint author), Res Triangle Inst, 180 NASA Rd,5A Hunsacker Loop, Hampton, VA 23681 USA. NR 0 TC 0 Z9 0 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 0885-8985 J9 IEEE AERO EL SYS MAG JI IEEE Aerosp. Electron. Syst. Mag. PD AUG PY 2002 VL 17 IS 8 BP 4 EP 10 DI 10.1109/MAES.2002.1028077 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA 589DY UT WOS:000177744100003 ER PT J AU Maneri, E Gawronski, W AF Maneri, E Gawronski, W TI A method and a GUI for the creation of azimuth-track level-pointing-error corrections SO IEEE ANTENNAS AND PROPAGATION MAGAZINE LA English DT Article DE space vehicle tracking; scanning antennas; pointing systems; antenna mechanical factors; antenna tolerance analysis; satellite tracking; satellite communications AB The JPL beam-waveguide (BWG) antennas are used for spacecraft tracking and for radio-astronomy observations. They are mounted on wheels that rotate around an uneven azimuth track, causing antenna deformations, and reducing pointing accuracy. The pointing errors affected by the track irregularities are repeatable, and can therefore be calibrated. The effects of the irregularities of the track can continually be corrected by using a lookup table, created by the interface presented below. This paper is a continuation of previous work [1] a appearing in this Magazine. It describes the processing the inclinometer data, which includes the verification of repeatability, smoothing, slow-trend removal, re-sampling, and adjustment to a standard format. It also presents a user-friendly interface that process field data and creates a lookup table for pointing-error correction by clicking appropriate buttons on a computer screen. The GUI was tested with the JPL BWG antennas, and may be used with any antennas utilizing an azimuth track. C1 MIT, Cambridge, MA 02139 USA. CALTECH, Jet Prop Lab, Commun Ground Syst Sect, Pasadena, CA 91109 USA. RP Maneri, E (reprint author), MIT, 77 Massachusetts Ave, Cambridge, MA 02139 USA. EM emaneri@mit.edu; wodek.k.Gawronski@jpl.nasa.gov NR 1 TC 1 Z9 1 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 1045-9243 EI 1558-4143 J9 IEEE ANTENN PROPAG M JI IEEE Antennas Propag. Mag. PD AUG PY 2002 VL 44 IS 4 BP 23 EP 29 DI 10.1109/MAP.2002.1043144 PG 7 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA 606CW UT WOS:000178716500004 ER PT J AU Sudesh, V Asai, K Shimamura, K Fukuda, T AF Sudesh, V Asai, K Shimamura, K Fukuda, T TI Pulsed laser action in Tm,Ho : LuLiF4 and Tm,Ho : YLiF4 crystals using a novel quasi-end-pumping technique SO IEEE JOURNAL OF QUANTUM ELECTRONICS LA English DT Article DE diode-pumped lasers; lens duct; quasi-end-pumping; Tm,Ho : LuLF; Tm,Ho : YLF ID ROOM-TEMPERATURE; YLF LASER; MU-M; TM; HO; OPERATION; SPECTROSCOPY; GROWTH AB A number of good quality thulium and holmium-codoped LuLiF4 and YLiF4 single crystals were successfully grown by the Czochralski crystal growth method under a CF4 atmosphere. Using a novel diode-pumped, quasi-end-pump scheme incorporating two lens ducts, pulsed laser action is achieved in 5%Tm,0.5%Ho: LuLiF4 and 5%Tm,0.5%Ho: YLiF4 crystals, at various pulse repetition frequencies and temperatures. At 10 Hz and at an operating temperature of 273 K, slope efficiencies (optical to optical efficiencies) with respect to the incident pump energies of 12.9% (9.2%) and 7.4% (5.2%) were demonstrated in the grown Tm,Ho: LuLiF4 and Tm,Ho: YLiF4 crystals, respectively. Free running laser output energies in excess of 30 mJ (LuLiF4) and 17 mJ (YLF) were measured. C1 Tohoku Univ, Inst Mat Res, Sendai, Miyagi 9808577, Japan. Tohoku Inst Technol, Taihaku Ku, Sendai, Miyagi 9820831, Japan. RP NASA, Langley Res Ctr, Hampton, VA 23681 USA. EM sudesh@stenet.com RI Fukuda, Tsuguo/D-1309-2010 NR 22 TC 25 Z9 25 U1 1 U2 7 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0018-9197 EI 1558-1713 J9 IEEE J QUANTUM ELECT JI IEEE J. Quantum Electron. PD AUG PY 2002 VL 38 IS 8 BP 1102 EP 1109 DI 10.1109/JQE.2002.801006 PG 8 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 580EH UT WOS:000177221700017 ER PT J AU Ponchak, GE Tentzeris, EM AF Ponchak, GE Tentzeris, EM TI Finite ground coplanar waveguide (FGC) low loss, low coupling 90-degree crossover junctions SO IEEE TRANSACTIONS ON ADVANCED PACKAGING LA English DT Article; Proceedings Paper CT IEEE MTT-S International Microwave Symposium (IMS2000) CY JUN 11-16, 2000 CL BOSTON, MA SP IEEE, MTT S DE coplanar waveguide; coupling; finite ground coplanar waveguide; planar transmission lines; transmission lines AB Microwave and millimeter-wave integrated circuits and RF distribution networks often require two transmission lines to cross over each other. In this paper, experimental measurements and three-dimensional (3-D) finite difference time domain analysis are used to thoroughly characterize coplanar waveguide (CPW) and finite ground coplanar waveguide (FGC 90-degree crossover junctions. It is shown that FGC crossover junctions have approximately 15 dB lower coupling than CPW crossover junctions. Furthermore, it is shown that the FGC junctions do not excite the parasitic slotline mode, whereas, the CPW junctions do excite the slotline mode. The results presented indicate that the FGC crossover junction is easier to implement and has better characteristics than the CPW crossover junction. C1 NASA, Glenn Res Ctr, Electron Device Technol Branch, Cleveland, OH 44135 USA. Georgia Inst Technol, Sch Elect & Comp Engn, Atlanta, GA 30332 USA. RP Ponchak, GE (reprint author), NASA, Glenn Res Ctr, Electron Device Technol Branch, Cleveland, OH 44135 USA. NR 9 TC 6 Z9 6 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 1521-3323 J9 IEEE T ADV PACKAGING JI IEEE Trans. Adv. Packag. PD AUG PY 2002 VL 25 IS 3 BP 385 EP 392 DI 10.1109/TADVP.2002.805314 PG 8 WC Engineering, Manufacturing; Engineering, Electrical & Electronic; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 637DU UT WOS:000180497000009 ER PT J AU Ofria, C Adami, C Collier, TC AF Ofria, C Adami, C Collier, TC TI Design of evolvable computer languages SO IEEE TRANSACTIONS ON EVOLUTIONARY COMPUTATION LA English DT Letter DE auto-adaptive systems; computer languages; digital life; evolvability; robustness ID DIGITAL ORGANISMS; EVOLUTION; COMPLEXITY; ROBUSTNESS AB We investigate common design decisions for constructing a computational genetic language in an autoadaptive system. Such languages must support self-replication and are typically Turing-complete so as not to limit the types of computations they can perform. We examine the importance of using templates to denote locations in the genome, the methods by which those templates are located (direct-matching versus complement-matching), methods used in the calculation of genome length and the size and complexity of the language. For each test, we examine the effects on the rate of evolution of the populations and isolate those factors that contribute to it, most notably the organisms' ability to withstand mutations. C1 Michigan State Univ, Dept Comp Sci & Engn, E Lansing, MI 48824 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif Los Angeles, Div Organizm Biol Ecol & Evolut, Los Angeles, CA 90095 USA. RP Ofria, C (reprint author), Michigan State Univ, Dept Comp Sci & Engn, E Lansing, MI 48824 USA. RI Adami, Christoph/A-5181-2009; Adami, Christoph/A-9675-2011; OI Adami, Christoph/0000-0002-2915-9504; Ofria, Charles/0000-0003-2924-1732 NR 17 TC 10 Z9 10 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 1089-778X J9 IEEE T EVOLUT COMPUT JI IEEE Trans. Evol. Comput. PD AUG PY 2002 VL 6 IS 4 BP 420 EP 424 DI 10.1109/TEVC.2002.802442 PG 5 WC Computer Science, Artificial Intelligence; Computer Science, Theory & Methods SC Computer Science GA 587LG UT WOS:000177641600011 ER PT J AU Gao, BC Yang, P Han, W Li, RR Wiscombe, WJ AF Gao, BC Yang, P Han, W Li, RR Wiscombe, WJ TI An algorithm using visible and 1.38-mu m channels to retrieve cirrus cloud reflectances from aircraft and satellite data SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE atmosphere; cirrus clouds; remote sensing ID REMOTELY-SENSED DATA; SCATTERING; AEROSOL; MODIS; HIRS AB The Moderate Resolution Imaging Spectro-Radiometer (MODIS) on the Terra Spacecraft has a channel near 1.38 mum for remote sensing of high clouds from space. The implementation of this channel on MODIS was primarily based on previous analysis of hyperspectral imaging data collected with the Airborne Visible Infrared Imaging Spectrometer (AVIRIS). In this paper, we describe an algorithm to retrieve cirrus bidirectional reflectance using channels near 0.66 and 1.38 mum. It is shown that the apparent reflectance of the 1.38-mum channel is essentially the bidirectional reflectance of cirrus clouds attenuated by the absorption of water vapor above cirrus clouds. A practical algorithm based on the scatterplot of 1.38-mum channel apparent reflectance versus 0.66-mum channel apparent reflectance has been developed to scale the effect of water vapor absorption so that the true cirrus reflectance in the visible spectral region can be obtained. To illustrate the applicability of the present algorithm, results for cirrus reflectance retrievals from AVIRIS and MODIS data are shown. The derived cirrus reflectance in the spectral region of 0.4-1 mum can be used to remove cirrus contamination in a satellite image obtained at a visible channel. An example of such application is shown. The spatially averaged cirrus reflectances derived from MODIS data can be used to establish global cirrus climatology, as is demonstrated by a sample global cirrus reflectance image. C1 USN, Res Lab, Remote Sensing Div, Washington, DC 20375 USA. Texas A&M Univ, Dept Atmospher Sci, College Stn, TX 77843 USA. Amer Chem Soc, Publicat Informat Technol Div, Washington, DC 20036 USA. NASA, Goddard Space Flight Ctr, Climate & Radiat Branch, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, Greenbelt, MD 20771 USA. RP Gao, BC (reprint author), USN, Res Lab, Remote Sensing Div, Washington, DC 20375 USA. RI Yang, Ping/B-4590-2011; Wiscombe, Warren/D-4665-2012 OI Wiscombe, Warren/0000-0001-6844-9849 NR 22 TC 85 Z9 88 U1 3 U2 14 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 AUG PY 2002 VL 40 IS 8 BP 1659 EP 1668 DI 10.1109/TGRS.2002.802454 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 599KR UT WOS:000178334200001 ER PT J AU Chen, CW Zebker, HA AF Chen, CW Zebker, HA TI Phase unwrapping for large SAR interferograms: Statistical segmentation and generalized network models SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE network optimization; statistical estimation; synthetic aperture radar interferometry; two-dimensional phase unwrapping ID RADAR INTERFEROMETRY; VORONOI DIAGRAMS; ALGORITHM AB Two-dimensional (2-D) phase unwrapping is a key step in the analysis of interferometric synthetic aperture radar (InSAR) data. While challenging even in the best of circumstances, this problem poses unique difficulties when the dimensions of the interferometric input data exceed the limits of one's computational capabilities. In order to deal with such cases, we propose a technique for applying the statistical-cost, network-flow phase-unwrapping algorithm (SNAPHU) of Chen and Zebker to large datasets. Specifically, we introduce a methodology whereby a large interferogram is partitioned into a set of several smaller tiles that are unwrapped individually and then divided further into independent, irregularly shaped reliable regions. These regions are subsequently assembled into a full unwrapped solution, with the phase offsets between regions computed in a secondary optimization problem whose objective is to maximize the a posteriori probability of the final solution. As this secondary problem assumes the same statistical models as employed in the initial tile-unwrapping stage, the technique results in a solution that approximates the solution that would have been obtained had the full-size interferogram been unwrapped as a single piece. The secondary problem is framed in terms of network-flow ideas, allowing the use of an existing nonlinear solver. Applying the algorithm to a large topographic interferogram acquired over central Alaska, we find that the technique is less prone to unwrapping artifacts than more simple tiling approaches. C1 Stanford Univ, Dept Elect Engn, Stanford, CA 94305 USA. Stanford Univ, Dept Geophys, Stanford, CA 94305 USA. RP Chen, CW (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 21 TC 126 Z9 134 U1 3 U2 19 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 AUG PY 2002 VL 40 IS 8 BP 1709 EP 1719 DI 10.1109/TGRS.2002.802453 PG 11 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 599KR UT WOS:000178334200005 ER PT J AU Le Moigne, J Campbell, WJ Cromp, RF AF Le Moigne, J Campbell, WJ Cromp, RF TI An automated parallel image registration technique based on the correlation of wavelet features SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE georegistration; image fusion; image processing; parallel processing; wavelet decomposition ID TROPICAL DEFORESTATION; AVHRR IMAGERY; ACCURACY; MISREGISTRATION; DECOMPOSITION; RECOGNITION; TRANSFORMS; RESOLUTION; SYSTEM AB With the increasing importance of multiple multi-platform remote sensing missions, fast and automatic integration of digital data from disparate sources has become critical to the success of these endeavors. Our work utilizes maxima of wavelet coefficients to form the basic features of a correlation-based automatic registration algorithm. Our wavelet-based registration algorithm is tested successfully with data from the National Oceanic and Atmospheric Administration (NOAA) Advanced Very High Resolution Radiometer (AVHRR) and the Landsat Thematic Mapper (TM), which differ by translation and/or rotation. By the choice of high-frequency wavelet features, this method is similar to an edge-based correlation method, but by,exploiting the multiresolution nature of a wavelet decomposition, our method achieves higher computational speeds for comparable accuracies. This algorithm has been implemented on a single-instruction multiple-data (SIMD) massively parallel computer, the MasPar MP-2, as well as on the CrayT3D, the, Cray T3E, and a Beowulf cluster of Pentium workstations. C1 NASA, Goddard Space Flight Ctr, Appl Informat Sci Branch, Greenbelt, MD 20771 USA. RP Le Moigne, J (reprint author), NASA, Goddard Space Flight Ctr, Appl Informat Sci Branch, Code 935, Greenbelt, MD 20771 USA. NR 79 TC 72 Z9 74 U1 1 U2 12 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 AUG PY 2002 VL 40 IS 8 BP 1849 EP 1864 DI 10.1109/TGRS.2002.802501 PG 16 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 599KR UT WOS:000178334200017 ER PT J AU Gabriel, AK AF Gabriel, AK TI A simple model for SAR azimuth speckle, focusing, and interferometric decorrelation SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE azimuth focusing; decorrelation speckle; interferometry; radar; speckle; synthetic aperture radar (SAR) ID RADAR INTERFEROMETRY AB The phenomenon of speckle in synthetic aperture radar (SAR) images is well known as a characteristic grainy appearance of radar images. Speckle is frequently a significant obstacle to visual interpretations of radar data or target identification. In addition, it is usually the dominant noise source in SAR interferometry, since it is responsible for image decorrelation that degrades interferometric fringes, places severe. constraints on orbits, and limits the accuracy of height measurements. This communication deals with the geometric sources of speckle. This conventional picture is extended to the case of vertically separated scatterers, and the formulation that results is applied to the structurally similar topics of azimuth focusing, interferometric decorrelation from defocusing, and atmospheric phase delays. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Gabriel, AK (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 TC 2 Z9 2 U1 0 U2 0 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 AUG PY 2002 VL 40 IS 8 BP 1885 EP 1889 DI 10.1109/TGRS.2002.802456 PG 5 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 599KR UT WOS:000178334200020 ER PT J AU Thompson, DJ Godfrey, G Williams, SM Grove, JE Mizuno, T Sadrozinski, HFW Kamae, T Ampe, J Briber, S Dann, J Silva, JDEDE Dubois, R Fukazawa, Y Giebels, B Haller, G Handa, T Hartman, RC Hirano, K Hirayama, M Johnson, RP Johnson, WN Kavelaars, A Kelly, H Kliewer, S Kotani, T Krizmanic, J Kroeger, W Kuss, M Lauben, D Linder, T Lovellette, M Lumb, N Manildi, J Michelson, P Mizushima, H Moiseev, A Nolan, PL Ogata, S Ormes, JF Ozaki, M Paliaga, G Phlips, BF Ritz, S Rochester, LS Roterman, FM Rowe, WA Russell, JJ Schaefer, R Schalk, T Sheppard, D Singh, S Sjogren, M Spandre, G Usher, T Valtersson, P Waite, AP Wallace, J Webster, A Wood, D AF Thompson, DJ Godfrey, G Williams, SM Grove, JE Mizuno, T Sadrozinski, HFW Kamae, T Ampe, J Briber, S Dann, J Silva, JDEDE Dubois, R Fukazawa, Y Giebels, B Haller, G Handa, T Hartman, RC Hirano, K Hirayama, M Johnson, RP Johnson, WN Kavelaars, A Kelly, H Kliewer, S Kotani, T Krizmanic, J Kroeger, W Kuss, M Lauben, D Linder, T Lovellette, M Lumb, N Manildi, J Michelson, P Mizushima, H Moiseev, A Nolan, PL Ogata, S Ormes, JF Ozaki, M Paliaga, G Phlips, BF Ritz, S Rochester, LS Roterman, FM Rowe, WA Russell, JJ Schaefer, R Schalk, T Sheppard, D Singh, S Sjogren, M Spandre, G Usher, T Valtersson, P Waite, AP Wallace, J Webster, A Wood, D CA GLAST Large Area Telescope Collabo TI Gamma-ray large-area space telescope (GLAST) balloon flight engineering model: Overview SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 2001 Nuclear Science Symposium CY NOV 04-10, 2001 CL SAN DIEGO, CALIFORNIA DE gamma rays; instrumentation; telescopes ID BEAM TEST AB The Gamma-ray Large Area Space Telescope (GLAST) Large Area Telescope (LAT) is a pair-production high-energy (>20 MeV) gamma-ray telescope being built by an international partnership of astrophysicists and particle physicists for a satellite launch in 2006, designed to study a wide variety of high-energy astrophysical phenomena. As part of the development effort, the collaboration has built, a balloon flight engineering model (BFEM) for flight on a high-altitude scientific balloon. The BFEM is approximately the size of one of the 16 GLAST-LAT towers and contains all the components of the full instrument: plastic scintillator anticoincidence system (ACD), high-Z foil/Si strip pair-conversion tracker (TKR), CsI hodoscopic calorimeter (CAL), triggering and data acquisition electronics (DAQ), commanding system, power distribution, telemetry, real-time data display, and ground data processing system. The principal goal of the balloon flight was to demonstrate the performance of this instrument configuration under conditions similar to those expected in orbit. Results from a balloon flight from Palestine, TX, on August 4, 2001, show that the BFEM successfully obtained gamma-ray data in this high-background environment. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Stanford Linear Accelerator Ctr, Menlo Pk, CA 94025 USA. Stanford Univ, Stanford, CA 94305 USA. USN, Res Lab, Washington, DC 20375 USA. Hiroshima Univ, Higashihiroshima 7398526, Japan. Univ Calif Santa Cruz, Santa Cruz, CA 95064 USA. USN, Res Lab & Praxis, Washington, DC 20375 USA. Independence HS, San Jose, CA 95133 USA. St Ignatius HS, San Francisco, CA 94116 USA. Paso Robles HS, Paso Robles, CA 93446 USA. INFN, I-56100 Pisa, Italy. Univ Pisa, I-56100 Pisa, Italy. Watsonville HS, Watsonville, CA 95076 USA. Stanford Linear Accelerator Ctr, Kanagawa 2298510, Japan. Inst Space & Astronaut Sci, Kanagawa 2298510, Japan. Stanford Linear Accelerator Ctr, Stanford, CA 94305 USA. Royal Inst Technol, S-10044 Stockholm, Sweden. RP Thompson, DJ (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. RI Nolan, Patrick/A-5582-2009; Thompson, David/D-2939-2012; Kuss, Michael/H-8959-2012; Ozaki, Masanobu/K-1165-2013; Johnson, Neil/G-3309-2014; Schaefer, Robert/C-2119-2016 OI Thompson, David/0000-0001-5217-9135; Schaefer, Robert/0000-0003-3692-0223 NR 7 TC 10 Z9 10 U1 1 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD AUG PY 2002 VL 49 IS 4 BP 1898 EP 1903 DI 10.1109/TNS.2002.801548 PN 1 PG 6 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 610FY UT WOS:000178951100055 ER PT J AU Burnett, TH Chekhtman, A Silva, EDE Dubois, R Flath, D Gable, I Grove, JE Hartman, RC Kamae, T Kavelaars, A Kelly, H Kotani, T Kuss, M Lauben, D Lindner, T Lumb, N Mizuno, T Moiseev, A Ozaki, M Rochester, LS Schaefer, R Spandre, G Thompson, DJ Usher, T Young, K AF Burnett, TH Chekhtman, A Silva, EDE Dubois, R Flath, D Gable, I Grove, JE Hartman, RC Kamae, T Kavelaars, A Kelly, H Kotani, T Kuss, M Lauben, D Lindner, T Lumb, N Mizuno, T Moiseev, A Ozaki, M Rochester, LS Schaefer, R Spandre, G Thompson, DJ Usher, T Young, K CA GLAST Large Area Telescope Collabo TI Gamma-ray large-area space telescope (GLAST) balloon flight data handling overview SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 2001 Nuclear Science Symposium CY NOV 04-10, 2001 CL SAN DIEGO, CALIFORNIA DE astronomical satellites; balloons; data handling; data processing; gamma-ray astronomy detectors; GLAST; software AB The gamma-ray large-area space telescope (GLAST) balloon flight engineering model (BFEM) represents one of 16 towers that constitute the large area telescope (LAT), a high-energy (> 20 MeV) gamma-ray pair-production telescope being built by an international partnership of astrophysicists and particle physicists for a satellite launch in 2006. The prototype tower consists of a Pb/Si pair-conversion tracker (TKR), a CsI hodoscopic calorimeter (CAL), an anticoincidence detector (ACD), and an autonomous data acquisition (DAQ) system. The self-triggering capabilities and performance of the detector elements have been previously characterized using positron, photon and hadron beams. External target scintillators were placed above the instrument to act as sources of hadronic showers. This paper provides a comprehensive description of the BFEM data-reduction process, from receipt of the flight data from telemetry through event reconstruction and background rejection cuts. The goals of the ground analysis presented here are to verify the functioning of the instrument and to validate the reconstruction software and the background-rejection scheme. C1 Univ Washington, Seattle, WA 98195 USA. USN, Res Lab, Washington, DC 20375 USA. Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Univ Victoria, Victoria, BC V8W 2Y2, Canada. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Pisa, Ist Nazl Fis Nucl, I-56010 Pisa, Italy. Stanford Univ, Stanford, CA 94305 USA. Univ Lyon 1, IPNL, F-69622 Villeurbanne, France. Hiroshima Univ, Higashihiroshima 7398511, Japan. Inst Space & Aeronaut Sci, Sagamihara, Kanagawa 2298510, Japan. RP Burnett, TH (reprint author), Univ Washington, Seattle, WA 98195 USA. RI Thompson, David/D-2939-2012; Kuss, Michael/H-8959-2012; Ozaki, Masanobu/K-1165-2013; Schaefer, Robert/C-2119-2016 OI Thompson, David/0000-0001-5217-9135; Schaefer, Robert/0000-0003-3692-0223 NR 8 TC 5 Z9 5 U1 2 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD AUG PY 2002 VL 49 IS 4 BP 1904 EP 1908 DI 10.1109/TNS.2002.801536 PN 1 PG 5 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 610FY UT WOS:000178951100056 ER PT J AU Chauhan, NS AF Chauhan, NS TI Soil moisture inversion at L-band using a dual-polarization technique: a model-based sensitivity analysis SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID ELECTROMAGNETIC BACKSCATTERING; MICROWAVE EMISSION; VEGETATION; RADIOMETER; RADAR AB The inverse problem of estimating soil moisture from vegetated and non-vegetated terrain is investigated using a passive microwave technique. The radiometer response at L-band is modelled by the Peake's approach that involves the integration of bistatic scattering coefficients to calculate surface emissivity. For vegetated terrain, a discrete scatter model employing the distorted Born approximation is used to obtain bistatic scattering coefficients. For non-vegetated rough surface, the Kirchhoff's rough surface approximation is used to calculate bistatic scattering coefficients. A series of vegetated and non-vegetated surfaces are simulated for this study by changing vegetation densities and ground roughness conditions. The forward model is simplified so that it can be inverted with a minimum of auxiliary information about the vegetation and the ground. An inversion procedure is set up such that the ratio of horizontal to vertical Fresnel reflectivity is expressed in terms of dual-polarized microwave brightness temperatures (available from the forward model or a radiometer). The reflectivity ratio expression is then solved to obtain soil moisture. In the case of weak vegetation such as soybean canopy, no information regarding vegetation is necessary in the inversion procedure because the difference between horizontal and vertical optical depth is assumed to be negligibly small at low to medium viewing angles. The consequence of this assumption on the soil moisture estimation from canopies of higher Leaf Area Index (LAI) is analysed. Similarly, in the case of non-vegetated rough terrain, inversion is carried out without information about rough surface because the rms surface roughness height cancels out in ratioing of the Fresnel reflectivity. To account for instrument and other errors in experimental data, a random noise is added to model data and the rms error in soil moisture inversion is calculated for vegetated and non-vegetated terrain. A comparison of the dual polarization with single ( horizontal) polarization technique reveals that the dual polarization is a better technique for soil moisture estimation. The sensitivities and implications of a priori information are discussed in the context of developing a soil moisture estimation algorithm from satellites to be launched in the forthcoming space missions. C1 Aerosp Corp, NPOESS Integrated Program Off, Silver Spring, MD 20910 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Raytheon Co, Lexington, MA 02421 USA. RP Chauhan, NS (reprint author), Aerosp Corp, NPOESS Integrated Program Off, 8455 Colesville Rd,Suite 1450, Silver Spring, MD 20910 USA. NR 26 TC 6 Z9 6 U1 0 U2 0 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 AUG PY 2002 VL 23 IS 16 BP 3209 EP 3227 DI 10.1080/01431160210136597 PG 19 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 584BG UT WOS:000177446900006 ER PT J AU Ji, YM Stocker, E AF Ji, YM Stocker, E TI An overview of the TRMM/TSDIS fire algorithm and product SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID IDENTIFICATION; RESOLUTION; TROPICS; AVHRR; SMOKE AB Since December 1997, the Tropical Rainfall Measuring Mission (TRMM) has provided tremendous opportunities for the understanding of global rainfall variability and mechanisms, as well as for retrieving and understanding of surface properties such as sea surface temperature and forest fires. The TRMM Science Data and Information System (TSDIS) fire algorithm routinely produces daily and monthly global fire products. These products have been achieved since January 1998. Any interested users may download these products from the TSDIS web page. The TSDIS night-time fire algorithm is a traditional threshold method using only the Visible and Infrared Scanner (VIRS) thermal band brightness temperatures. The daytime algorithm is a contextual approach that uses VIRS visible/near-infrared band reflectance and the University of Maryland (UMD) 1 km land type data to reject false fire pixels. This study compared the TSDIS fire products with the European Commission (EC) Joint Research Center (JRC) 1 km AVHRR fire products. The two products were in agreement on spatial and temporal variations over areas where both data were available. An analysis of the TSDIS monthly fire products during the two years of 1998 and 1999 manifested seasonal cycles of biomass fires over Southeast Asia, Africa, North America and South America. The data also showed interannual variations associated with the ENSO cycle in Central America and the Indonesian region during the two years. We compared the TSDIS monthly fire products with the aerosol index products of the Total Ozone Mapping Spectrometer ( TOMS) of the NASA Earth Probe satellite. The results indicated that the major aerosol variations of the global atmosphere during the two years were associated with the smoke released by the biomass fires. C1 George Mason Univ, Inst Computat Sci & Informat, Fairfax, VA 22030 USA. NASA, GSFC, TRMM, TSDIS, Greenbelt, MD 20770 USA. RP Ji, YM (reprint author), George Mason Univ, Inst Computat Sci & Informat, Fairfax, VA 22030 USA. NR 21 TC 8 Z9 11 U1 0 U2 1 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD AUG PY 2002 VL 23 IS 16 BP 3285 EP 3303 DI 10.1080/01431160110070816 PG 19 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 584BG UT WOS:000177446900010 ER PT J AU Kulikov, IK AF Kulikov, IK TI Trapped fermions in gravitational field SO INTERNATIONAL JOURNAL OF THEORETICAL PHYSICS LA English DT Article DE trapped fermions; gravitational field ID BOSE-EINSTEIN CONDENSATION; ATOMIC GAS AB Trapped noninteracting Fermi gas in an external gravitational field in Newtonian approximation is considered. Analytical equations for chemical potential, internal energy, and specific heat of trapped Fermi gas are computed. The spatial distribution of completely degenerate fermions in nonhomogeneous gravitational field is calculated. The effects of the influence of gravitational field on Fermi gas are discussed. C1 CALTECH, Jet Prop Lab, Quantum Comp Technol Grp, Pasadena, CA 91109 USA. RP Kulikov, IK (reprint author), CALTECH, Jet Prop Lab, Quantum Comp Technol Grp, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0020-7748 J9 INT J THEOR PHYS JI Int. J. Theor. Phys. PD AUG PY 2002 VL 41 IS 8 BP 1481 EP 1490 AR UNSP PP597-379783-02 DI 10.1023/A:1020132430692 PG 10 WC Physics, Multidisciplinary SC Physics GA 591YU UT WOS:000177909000002 ER PT J AU Snyder, GJ Fleurial, JP Caillat, T Yang, RG Chen, G AF Snyder, GJ Fleurial, JP Caillat, T Yang, RG Chen, G TI Supercooling of Peltier cooler using a current pulse SO JOURNAL OF APPLIED PHYSICS LA English DT Article AB The operation of a Peltier cooler can be temporarily enhanced by utilizing the transient response of a current pulse. The performance of such a device, using (Bi,Sb)(2)Te-3-based thermoelectric elements, was examined from -70 to 55 degreesC. We establish both theoretically and experimentally the essential parameters that describe the pulse cooling effect, such as the minimum temperature achieved, maximum temperature overshoot, time to reach minimum temperature, time while cooled, and time between pulses. Using simple theoretical and semiempirical relationships the dependence of these parameters on the current pulse amplitude, temperature, thermoelectric element length, thermoelectric figure of merit and thermal diffusivity is established. At large pulse amplitudes the amount of pulse supercooling is proportional to the maximum steady-state difference in temperature. This proportionality factor is about half that expected theoretically. This suggests that the thermoelectric figure of merit is the key materials parameter for pulse cooling. For this cooler, the practical optimum pulse amplitude was found to be about three times the optimum steady-state current. A pulse cooler was integrated into a small commercial thermoelectric three-stage cooler and it provided several degrees of additional cooling for a period long enough to operate a laser sensor. The improvement due to pulse cooling is about the equivalent of two additional stages in a multistage thermoelectric cooler. (C) 2002 American Institute of Physics. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. MIT, Dept Mech Engn, Cambridge, MA 02139 USA. RP Snyder, GJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Yang, Ronggui/H-1278-2011; Snyder, G. Jeffrey/E-4453-2011; Chen, Gang/J-1325-2014; Snyder, G/I-2263-2015 OI Snyder, G. Jeffrey/0000-0003-1414-8682; Chen, Gang/0000-0002-3968-8530; NR 13 TC 66 Z9 67 U1 2 U2 18 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 AUG 1 PY 2002 VL 92 IS 3 BP 1564 EP 1569 DI 10.1063/1.1489713 PG 6 WC Physics, Applied SC Physics GA 574UJ UT WOS:000176907700063 ER PT J AU von Hunerbein, S Bradley, S Browell, E AF von Hunerbein, S Bradley, S Browell, E TI Untitled - Preface SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Editorial Material C1 Univ Salford, Salford M5 4WT, Lancs, England. NASA, Langley Res Ctr, Langley, VA USA. RP von Hunerbein, S (reprint author), Univ Salford, Salford M5 4WT, Lancs, England. NR 0 TC 0 Z9 0 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 AUG PY 2002 VL 19 IS 8 BP 1137 EP 1137 DI 10.1175/1520-0426(2002)019<1137:P>2.0.CO;2 PG 1 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 580UD UT WOS:000177253400001 ER PT J AU Hazeltine, E AF Hazeltine, E TI Focusing on the big picture with fMRI: Consciousness and temporal flux SO JOURNAL OF COGNITIVE NEUROSCIENCE LA English DT Article ID CORTEX C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Hazeltine, E (reprint author), NASA, Ames Res Ctr, Mail Stop 262-4, Moffett Field, CA 94035 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU M I T PRESS PI CAMBRIDGE PA FIVE CAMBRIDGE CENTER, CAMBRIDGE, MA 02142 USA SN 0898-929X J9 J COGNITIVE NEUROSCI JI J. Cogn. Neurosci. PD AUG PY 2002 VL 14 IS 6 BP 836 EP 837 DI 10.1162/089892902760191054 PG 2 WC Neurosciences; Psychology, Experimental SC Neurosciences & Neurology; Psychology GA 583DP UT WOS:000177390900005 PM 12191450 ER PT J AU Kratz, DP Priestley, KJ Green, RN AF Kratz, DP Priestley, KJ Green, RN TI Establishing the relationship between the CERES window and total channel measured radiances for conditions involving deep convective clouds at night SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE CERES; TRMM; radiometer; three-channel-intercomparison; deep-convective-clouds; infrared-window ID ENERGY SYSTEM CERES; RADIATION BUDGET EXPERIMENT; RAINFALL MEASURING MISSION; ATMOSPHERIC FLUXES; COOLING RATES; WATER-VAPOR; SPACECRAFT; VALIDATION; ERBE AB [1] Characterizing the stability of the Clouds and the Earth's Radiant Energy System (CERES) instrument is critical to obtaining accurate measurements of the radiative energy budget of the Earth's atmosphere-surface system. Composed of three broadband radiometers, the CERES instrument measures radiances in the shortwave (>2000 cm(-1)), infrared window (835-1250 cm(-1)), and total regions of the spectrum. Such a choice of radiometers does not allow for a straightforward three channel intercomparison of the CERES measurements. We observed, however, the outgoing infrared spectra of high, cold, optically thick clouds were fairly representative of blackbody emission. This observation suggested a potential relationship between the infrared window radiometer and longwave portion of the total radiometer. Using nighttime measurements made by the CERES instrument aboard the Tropical Rainfall Measuring Mission (TRMM) spacecraft during the first eight months of 1998, we were able to determine a highly correlated relationship between the infrared window and total channel radiances for conditions corresponding to high, cold, optically thick clouds. Comparisons were then made between the measurements and reference line-by-line calculations. From these comparisons, a quantified relationship was derived between the total and window channel radiances which could accurately reproduce one set of results from the other. Such a relationship has allowed for the establishment of a three channel intercomparison for the CERES instrument with an accuracy of similar to1% for the case of high, cold, optically thick clouds. An independent relationship based upon the tropical mean is shown to produce results which support the three channel analysis for the deep convective cloud systems. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Kratz, DP (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 24 TC 6 Z9 6 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0747-7309 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD AUG PY 2002 VL 107 IS D15 AR 4245 DI 10.1029/2001JD001170 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 610TR UT WOS:000178977400026 ER PT J AU Lingenfelser, GS Grose, WL AF Lingenfelser, GS Grose, WL TI Use of long-lived tracer observations to examine transport characteristics in the lower stratosphere SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE transport; stratosphere; HALOE; tracer ID HALOGEN OCCULTATION EXPERIMENT; ARRAY ETALON SPECTROMETER; POLAR VORTEX AIR; ATMOSPHERE RESEARCH SATELLITE; LAGRANGIAN-MEAN DIAGNOSTICS; ANTARCTIC OZONE HOLE; IN-SITU OBSERVATIONS; ARCTIC VORTEX; ISENTROPIC TRANSPORT; CHLORINE RADICALS AB [1] The Halogen Occultation Experiment (HALOE) CH(4) data were used in a modified Lagrangian-mean (MLM) analysis. The implemented MLM analysis is advantageous in that it provides a unique method for capturing tracer distributions and identifying so-called transport barriers (i.e., regions where quasi-horizontal transport is inhibited) and mixing regions, knowing only the mixing ratios of long-lived tracers. This analysis can be used with any long-lived tracer provided that adequate spatial coverage can be achieved either instantaneously or over a reasonably short period of time (i.e., characteristic time over which diabatic processes responsible for cross-isentropic transport are small or negligible, similar to7-10 days in the lower stratosphere). Previous authors have demonstrated the use of this technique with data from limb-sounding instruments which can provide near-hemispheric coverage in a day. We show how this technique can be implemented with HALOE occultation data. Because the solar occultation sampling pattern of HALOE requires similar to1 month to achieve near-hemispheric coverage, synoptic distributions of CH(4) are reconstructed using the UK Meteorological Office potential vorticity (PV) distributions, exploiting the tracer's correlation with PV. In previous studies, authors have used PV for filling voids in tracer distributions. It is concluded that an MLM cross section of CH(4) can be constructed from the HALOE occultation data, provided that a suitable synoptic distribution of PV can be obtained for the desired period. To illustrate the feasibility and usefulness of applying the MLM technique to HALOE reconstructed CH(4) data, transport characteristics in the lower stratosphere were investigated using CH(4) data for two different regimes ( polar and subtropical) at times when airborne in situ data were available. In this manner we were able to compare information available with respect to transport from the MLM equivalent length analyses with that provided by aircraft tracer-tracer correlations. The very good agreement between ER-2 and HALOE data observed in CH(4)-O(3) correlations and in CH(4) and O(3) near-coincident comparisons increased our confidence in using the HALOE data in the MLM equivalent length analyses. Unlike the satellite data, the ER-2 in situ measurements cannot be used in the MLM technique. Instead, correlations between the mixing ratios of various tracer constituents have been used extensively in the past to provide insight into the relative roles of chemistry and transport in the lower stratosphere. However, separating the effects of chemistry and transport and accurately interpreting tracer-tracer correlations is often difficult. We show that associating an aircraft tracer-tracer correlation with a coincident HALOE MLM equivalent length analysis may provide for a less ambiguous evaluation of the correlation in the sense that it provides information on transport processes in physical space. Also, there are obvious implications for use of MLM equivalent length analyses in regions/time frames when aircraft data are not available. C1 Sci Applicat Int Corp, NASA LaRC, Hampton, VA 23681 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Lingenfelser, GS (reprint author), Sci Applicat Int Corp, NASA LaRC, MS 401B, Hampton, VA 23681 USA. EM lingenfelser@larc.nasa.gov; w.l.grose@larc.nasa.gov NR 48 TC 3 Z9 3 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-ATMOS JI J. Geophys. Res.-Atmos. PD AUG PY 2002 VL 107 IS D15 AR 4253 DI 10.1029/2001JD001296 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 610TR UT WOS:000178977400020 ER PT J AU Lucarini, V Russell, GL AF Lucarini, V Russell, GL TI Comparison of mean climate trends in the Northern Hemisphere between National Centers for Environmental Prediction and two atmosphere-ocean model forced runs SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE historical climate change; Northern Hemisphere climatology; climate trends detection; statistical methods in climate data analysis; comparison with NCEP data; atmospheric data ID MICROWAVE SOUNDING UNIT; TEMPERATURE TRENDS; SURFACE; REANALYSIS; QUALITY AB [1] Results are presented for two greenhouse gas experiments of the Goddard Institute for Space Studies atmosphere-ocean model (AOM). The computed trends of surface pressure; surface temperature; 850, 500, and 200 mbar geopotential heights; and related temperatures of the model for the time frame 1960-2000 are compared with those obtained from the National Centers for Enviromental Prediction (NCEP) observations. The domain of interest is the Northern Hemisphere because of the higher reliability of both the model results and the observations. A spatial correlation analysis and a mean value comparison are performed, showing good agreement in terms of statistical significance for most of the variables considered in the winter and annual means. However, the 850 mbar temperature trends do not show significant positive correlation, and the surface pressure and 850 mbar geopotential height mean trends confidence intervals do not overlap. A brief general discussion about the statistics of trend detection is presented. The accuracy that this AOM has in describing the regional and NH mean climate trends inferred from NCEP through the atmosphere suggests that it may be reliable in forecasting future climate changes. C1 MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02138 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. MIT, Joint Program Sci & Policy Global Change, Cambridge, MA 02139 USA. RP Lucarini, V (reprint author), MIT, Dept Earth Atmospher & Planetary Sci, Bldg 54,Room 17-19, Cambridge, MA 02138 USA. NR 18 TC 3 Z9 3 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0747-7309 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD AUG PY 2002 VL 107 IS D15 AR 4270 DI 10.1029/2001JD001247 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 610TR UT WOS:000178977400010 ER PT J AU Luo, M Beer, R Jacob, DJ Logan, JA Rodgers, CD AF Luo, M Beer, R Jacob, DJ Logan, JA Rodgers, CD TI Simulated observation of tropospheric ozone and CO with the Tropospheric Emission Spectrometer (TES) satellite instrument SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE TES; tropospheric emission spectrometer; ozone; carbon monoxide; tropospheric chemistry; satellite remote sensing ID SPACE; MODEL; CHEMISTRY; RETRIEVAL; RADIANCES; POLLUTION; RADIATION AB [1] The Tropospheric Emission Spectrometer (TES) on board NASA's Aura satellite (to be launched in 2004) will provide measurements of global distributions of ozone, CO, and other key chemical species in the troposphere. In order for TES to meet a design lifetime of 5 years, it has been determined that a global survey strategy with similar to50% duty cycle must be identified. In this study, simulated concentrations of ozone and CO from the GEOS-CHEM global three-dimensional (3-D) model of troposphere chemistry are used as a time-varying synthetic atmosphere for demonstrating and assessing the capabilities of TES nadir observations. Autocorrelation analyses of the model species fields for different time lags identify a significant 1-day correlation and support a 1-day-on/1-day-off observation strategy. Three major steps are then taken to demonstrate and evaluate TES products: (1) species profiles along the TES orbit track are sampled from the model 3-D time-varying fields with cloudy scenes (50-60% of total scenes) removed; (2) nadir-retrieved profiles ("level 2 products") are obtained from these "true" synthetic profiles using TES retrieval characteristic functions; (3) interpolated daily global maps ("level 3 products") are generated to compare with the original model fields. The latter comparison indicates that the error in the level 3 products relative to the true fields for ozone and CO is <10% in &SIM;70% of cases and <20% in 80-90% of cases. The three major sources of error lie in the asynoptic orbital sampling, the retrieval, and the level 3 global mapping. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA. Univ Oxford, Oxford OX1 2JD, England. RP Luo, M (reprint author), CALTECH, Jet Prop Lab, MS 183-301,4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Chem, GEOS/C-5595-2014 NR 22 TC 13 Z9 13 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0747-7309 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD AUG PY 2002 VL 107 IS D15 AR 4270 DI 10.1029/2001JD000804 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 610TR UT WOS:000178977400006 ER PT J AU Piacentini, RD Alfano, OM Albizzati, ED Luccini, EA Herman, JR AF Piacentini, RD Alfano, OM Albizzati, ED Luccini, EA Herman, JR TI Solar ultraviolet irradiance for clear sky days incident at Rosario, Argentina: Measurements and model calculations SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE ultraviolet; irradiance; ozone; aerosol ID UV-RADIATION; LATITUDES; SURFACE; OZONE AB [1] Results of measurements are presented of clear-sky day solar UV irradiance (295-385 nm) in the August 1995 to June 1999 period at the Observatorio Astronomico de Rosario, Argentina, a place typical of the most populated Humid Pampa region of the country. The data give a detailed description of UV variation as a function of time in a given day and for different days of the year. Model calculations for clear-sky days at noon are done, employing the tropospheric ultraviolet visible radiation model (TUV) Madronich radiative transfer code, with the mean monthly ozone and aerosol content of the atmosphere and surface reflectivity provided by the Total Ozone Mapping Spectrometer (TOMS)/NASA instrument on board of the Earth Probe satellite. Two aerosol characteristics are tested in the model, rural-urban and mean urban, with the mean urban giving best agreement with the measurements. A simple mathematical expression is proposed for the "mean" typical curve, which gives a good approximation to the clear sky UV noon data for Rosario. It can be used for extending the results to nearby places and for comparison with other regions of the world having similar atmospheric and albedo conditions. C1 Univ Nacl Rosario, CONICET, Inst Fis Rosario, Grp Energia Solar, RA-2000 Rosario, Santa Fe, Argentina. Univ Nacl Rosario, Fac Ciencias Exactas Ingn & Agrimensura, RA-2000 Rosario, Santa Fe, Argentina. Univ Nacl Litoral, CONICET, INTEC, RA-3000 Santa Fe, Litoral, Argentina. Univ Nacl Rosario, Fac Ingn Quim, RA-2000 Rosario, Santa Fe, Argentina. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Piacentini, RD (reprint author), Univ Nacl Rosario, CONICET, Inst Fis Rosario, Grp Energia Solar, 27 de Febrero 210 Bis, RA-2000 Rosario, Santa Fe, Argentina. NR 20 TC 8 Z9 8 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0747-7309 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD AUG PY 2002 VL 107 IS D15 AR 4255 DI 10.1029/2001JD000586 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 610TR UT WOS:000178977400018 ER PT J AU Reale, O Dirmeyer, P AF Reale, O Dirmeyer, P TI Modeling the effect of land surface evaporation variability on precipitation variability. Part I: General response SO JOURNAL OF HYDROMETEOROLOGY LA English DT Article ID NUMERICAL WEATHER PREDICTION; CIRCULATION MODELS; BIOSPHERE MODEL; CLIMATE; GCM; PARAMETERIZATION; DEFORESTATION; SENSITIVITY; SIMULATION AB This is the first of a two-part article that investigates the impact of land surface evaporation variability on the interannual variability of precipitation and compares it with the impact caused by sea surface temperature variability. Previous works by Koster and Suarez and Koster et al. provide the general strategy to control oceanic and land surface evaporation. For this part of the study, their numerical experiments are repeated using the Center for Ocean-Land-Atmosphere Studies (COLA) general circulation model. However, emphasis is put on the dynamics of the response, including a discussion of the changes in the mean climate; in particular, it is observed that the suppressed land evaporation variability changes the mean Northern Hemisphere storm track and the mean position of the intertropical convergence zone, which in turn affect the mean precipitation. The analysis of the precipitation variance reveals a general agreement with previous works for the midlatitudes, whereas in the Tropics a stronger land-induced signal is detected. Furthermore, important regional differences in the response are found. Specifically, there is a predominant land signal over the Amazon region, in contrast to an equivalence between the land and ocean forcings over the Congo basin region. Finally, the model appears to be slightly more sensitive to seasonal-interannual variations of the land forcing than is the one adopted by Koster et al. C1 Ctr Ocean Land Atmosphere Studies, Calverton, MD USA. RP Reale, O (reprint author), NASA, Data Assimilat Off, Goddard Space Flight Ctr, Code 910-3, Greenbelt, MD 20771 USA. EM oreale@dao.gsfc.nasa.gov RI Dirmeyer, Paul/B-6553-2016 OI Dirmeyer, Paul/0000-0003-3158-1752 NR 28 TC 15 Z9 15 U1 1 U2 5 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 AUG PY 2002 VL 3 IS 4 BP 433 EP 450 DI 10.1175/1525-7541(2002)003<0433:MTEOLS>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 571GW UT WOS:000176710500005 ER PT J AU Reale, O Dirmeyer, P Schlosser, A AF Reale, O Dirmeyer, P Schlosser, A TI Modeling the effect of land surface evaporation variability on precipitation variability. Part II: Time- and space-scale structure SO JOURNAL OF HYDROMETEOROLOGY LA English DT Article ID BIOSPHERE MODEL AB This is the second of a two-part article investigating the impact of variations of land surface evaporability on the interannual variability of precipitation. The first goal of this part is to analyze the relationship between the atmospheric internal variability and the evaporative forcings. The hypothesis that the sum of ocean- and atmosphere-induced variabilities can be linearly amplified by the land variability is critically revisited and generally found not applicable to the climate model used and the numerical experiments conducted. A set of parameters to evaluate the departure from the linear behavior is defined, quantifying the impact of the different forcings over the total variability. Some areas of the world (e. g., the monsoon region, the continental United States, and southeastern Africa), where the impact of internal atmospheric dynamics on precipitation variability is small compared to the impact of the evaporative forcings, are localized. Over these areas, the variability of precipitation might be more predictable, given a good knowledge of the surface boundary forcings. In the second half of this article the time structure of the land forcing is analyzed, to quantify the contributions of the interannual variations, diurnal cycle, and high-frequency (i.e., synoptic scale) variations and compare them with the contribution of the oceanic forcing. The general conclusion is that interannual variability of both sea surface temperature and land evaporability is very important to the overall variability of precipitation over the Tropics. Over land in the subtropics and midlatitudes equatorward of the polar front there are also substantial feedbacks at the interannual scale. The impact of synoptic-scale variations of land evaporability is generally smaller, except for some areas in the midlatitudes near the polar front, particularly continental Eurasia and parts of North America. Finally, there is no general, widespread evidence showing the importance of the diurnal cycle of evaporability to the interannual variability of precipitation. However, strong regional differences are detected, and some tropical areas, like the Congo basin, where the diurnal cycle does contribute to the interannual variability of precipitation are outlined. C1 Ctr Ocean Land Atmosphere Studies, Calverton, MD USA. RP Reale, O (reprint author), NASA, Data Assimilat Off, Goddard Space Flight Ctr, Code 910-3, Greenbelt, MD 20771 USA. RI Dirmeyer, Paul/B-6553-2016 OI Dirmeyer, Paul/0000-0003-3158-1752 NR 7 TC 9 Z9 9 U1 0 U2 3 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 AUG PY 2002 VL 3 IS 4 BP 451 EP 466 DI 10.1175/1525-7541(2002)003<0451:MTEOLS>2.0.CO;2 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 571GW UT WOS:000176710500006 ER PT J AU Schlosser, CA Milly, PCD AF Schlosser, CA Milly, PCD TI A model-based investigation of soil moisture predictability and associated climate predictability SO JOURNAL OF HYDROMETEOROLOGY LA English DT Article ID LAND-SURFACE SCHEMES; ATMOSPHERIC PREDICTION; UNITED-STATES; CIRCULATION; WETNESS; TRANSPIRATION; PRECIPITATION; ASSIMILATION; SIMULATIONS; VARIABILITY AB Soil moisture predictability and the associated predictability of continental climate are explored as an initial-value problem, using a coupled land-atmosphere model with prescribed ocean surface temperatures. Ensemble simulations are designed to assess the extent to which initial soil moisture fields explain variance of future predictands (soil moisture, near-surface air temperature, and precipitation). For soil moisture, the decrease of explained variance with lead time can be characterized as a first-order decay process, and a predictability timescale is introduced as the lead time at which this decay reaches e(-1). The predictability timescale ranges from about 2 weeks or less (in midlatitudes during summer, and in the Tropics and subtropics) to 2-6 months (in mid- to high latitudes for simulations that start in late fall and early winter). The predictability timescale of the modeled soil moisture is directly related to the soil moisture's autocorrelation timescale. The degree of translation of soil moisture predictability to predictability of any atmospheric variable can be characterized by the ratio of the fraction of explained variance of the atmospheric variable to the fraction of explained soil moisture variance. By this measure, regions with the highest associated predictability of 30-day-mean near-surface air temperature (ratio greater than 0.5) are, generally speaking, coincident with regions and seasons of the smallest soil moisture predictability timescales. High associated temperature predictability is found where strong variability of soil moisture stress on evapotranspiration and abundant net radiation at the continental surface coincide. The associated predictability of 30-day-mean precipitation, in contrast, is very low. C1 Ctr Ocean Land Atmosphere Studies, Calverton, MD USA. RP Schlosser, CA (reprint author), NASA, Goddard Space Flight Ctr, Code 974, Greenbelt, MD 20771 USA. NR 42 TC 41 Z9 42 U1 0 U2 4 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 AUG PY 2002 VL 3 IS 4 BP 483 EP 501 DI 10.1175/1525-7541(2002)003<0483:AMBIOS>2.0.CO;2 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 571GW UT WOS:000176710500008 ER PT J AU Stein, TP Schluter, MD Galante, AT Soteropoulos, P Tolias, PP Grindeland, RE Moran, MM Wang, TJ Polansky, M Wade, CE AF Stein, TP Schluter, MD Galante, AT Soteropoulos, P Tolias, PP Grindeland, RE Moran, MM Wang, TJ Polansky, M Wade, CE TI Energy metabolism pathways in rat muscle under conditions of simulated microgravity SO JOURNAL OF NUTRITIONAL BIOCHEMISTRY LA English DT Article DE muscle atrophy; mRNA; microarray; space flight; beta-oxidation; glycolysis ID BED-REST; SKELETAL-MUSCLE; SOLEUS MUSCLE; SPACE-FLIGHT; FIBERS; EXPRESSION; SUSPENSION; CAPACITY; GRAVITY; ENZYMES AB Evidence from rats flown in space suggests that there is a decrease in the ability of the soleus muscle to oxidize long chain fatty acids during space flight. The observation suggests that a shift in the pathways involved in muscle fuel utilization in the absence of load on the muscle has occurred. It is also possible that the reduction is part of a general down-sizing of metabolic capacity since energy needs of inactive muscle are necessarily less. The rodent hind limb suspension model has proved to be a useful ground based model for studying the musculo-skeletal systems changes that occur with space flight. Microarray technology permits the screening of a large number of the enzymes of the relevant pathways thereby permitting a distinction to be made between a shift fuel utilization pattern or a general decrease in metabolic activity. The soleus muscle was isolated from 5 control and 5 hindlimb suspended rats (21 days) and the Affymetrix system for assessing gene expression used to determine the impact of hindlimb unloading on fuel pathways within the muscle of each animal. Results: Suspended rats failed to gain weight at the same rate as the controls (337 +/- 5 g vs 318 +/- 6 g, p < 0.05) and muscle mass from the soleus was reduced (135 +/- 3 mg vs 48 +/- 4 mg, p < 0.05). There was a consistent decrease (p < 0.05) in gene expression of proteins involved in fatty acid oxidation in the suspended group whereas glycolytic activity was increased (p < 0.05). Gene expressions of individual key regulatory enzymes reflected these changes. Carnitine palmitoyltransferase I and II were decreased (p < 0.05) whereas expression of hexokinase, phosphofructokinase and pyruvate kinase were increased (p < 0.05). Conclusion: Disuse atrophy is associated with a change in mRNA levels of enzymes involved in fuel metabolism indicative of a shift in substrate utilization away from fat towards glucose. (C) 2002 Elsevier Science Inc. All rights reserved. C1 Univ Med & Dent New Jersey, Sch Osteopath Med, Stratford, NJ 08084 USA. Publ Hlth Res Inst, Ctr Appl Genom, Newark, NJ 07103 USA. Univ Med & Dent New Jersey, NJMS, Newark, NJ 07103 USA. NASA, Ames Res Ctr, Moffett Field, CA 90035 USA. MCPHU, Sch Publ Hlth, Philadelphia, PA 19102 USA. RP Stein, TP (reprint author), Univ Med & Dent New Jersey, Sch Osteopath Med, Stratford, NJ 08084 USA. NR 41 TC 41 Z9 42 U1 0 U2 1 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0955-2863 J9 J NUTR BIOCHEM JI J. Nutr. Biochem. PD AUG PY 2002 VL 13 IS 8 BP 471 EP 478 AR PII S0955-2863(02)00195-X DI 10.1016/S0955-2863(02)00195-X PG 8 WC Biochemistry & Molecular Biology; Nutrition & Dietetics SC Biochemistry & Molecular Biology; Nutrition & Dietetics GA 586PM UT WOS:000177593200003 ER PT J AU Palko, JW Sayir, A Sinogeikin, SV Kriven, WM Bass, JD AF Palko, JW Sayir, A Sinogeikin, SV Kriven, WM Bass, JD TI Complete elastic tensor for mullite (similar to 2.5Al(2)O(3)center dot SiO2) to high temperatures measured from textured fibers SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID REFRACTIVE-INDEX; CONSTANTS; DEPENDENCE; SCATTERING; COMPOSITES; CRYSTALS AB Directionally solidified mullite fibers have been grown by the laser-heated, float-zone method from starting materials with a nominal composition of 3Al(2)O(3).2SiO(2). The fibers used in this study have large single-crystal regions with composition 2.5Al(2)O(3).SiO2 and [001] fiber axis orientation. The complete elastic tensor of these samples has been determined by Brillouin spectroscopy at room temperature and elevated temperatures up to 1200degreesC. Isotropic moduli (bulk, shear, and Young's) have been calculated using the Voigt-Reuss-Hill averaging scheme. The room-temperature values obtained are K-VRH = 173.5 +/- 6.9 GPa, G(VRH) = 88.0 +/- 3.5 GPa, E-VRH = 225.9 +/- 9.0 GPa. All moduli show gradual, linear decreases with temperature. The temperature derivatives obtained for the equivalent, isotropic moduli are dK(VRH)/dT = - 17.5 +/- 2.5 MPa/degreesC, dG(VRH)/dT = -8.8 +/- 1.4 MPa/degreesC, dE(VRH)/dT = -22.6 +/- 2.8 MPa/degreesC. Substantial differences between bulk properties calculated from the single-crystal measurements in this study and the properties reported in the literature for polycrystalline sintered mullite are identified, indicating the importance of factors such as microstructure, intergranular phases, and composition to the elasticity of mullite ceramics. C1 Univ Illinois, Dept Mat Sci & Engn, Urbana, IL 61801 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Palko, JW (reprint author), Univ Illinois, Dept Mat Sci & Engn, 1304 W Green St, Urbana, IL 61801 USA. RI Bass, Jay/G-2599-2013 NR 37 TC 21 Z9 21 U1 1 U2 5 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43086-6136 USA SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD AUG PY 2002 VL 85 IS 8 BP 2005 EP 2012 PG 8 WC Materials Science, Ceramics SC Materials Science GA 582RQ UT WOS:000177365300018 ER PT J AU Arkin, CR Griffin, TP Ottens, AK Diaz, JA Follistein, DW Adams, FW Helms, WR AF Arkin, CR Griffin, TP Ottens, AK Diaz, JA Follistein, DW Adams, FW Helms, WR TI Evaluation of small mass spectrometer systems for permanent gas analysis SO JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY LA English DT Article ID MINIATURE; ANALYZERS AB This work is aimed at understanding the aspects of designing a miniature mass spectrometer (MS) system. Several types of small MS systems are evaluated and discussed, including linear quadrupole, quadrupole ion trap, time of flight, and sector. Analysis of hydrogen, helium, oxygen, and argon in a nitrogen background with the concentrations of the components of interest ranging from 0 to 5000 parts per million (ppm). The performance of each system in terms of accuracy, precision, limits of detection, response time, recovery time, scan rate, size, and weight is assessed. The relative accuracies of the systems varied from <1% to similar to40% with an average below 10%. Relative precisions varied from 1% to 20%, with an average below 5%. The detection limits had a large distribution, ranging from 0.2 to 170 ppm. The systems had a diverse response time ranging from 4 to 210 s, as did the recovery time with a 6-to-210-s distribution. Most instruments had scan times near 1 s; however, one instrument exceeded 13 s. System weights varied from 9 to 52 kg and sizes ranged from 15 x 10(3) cm(3) to 110 x 10(3) cm(3). A performance scale is set up to rank each system, and an overall performance score is given to each system. (C) 2002 American Society for Mass Spectrometry. C1 Dynacs Inc, Kennedy Space Ctr, FL 32815 USA. Univ Florida, Dept Chem, Gainesville, FL 32611 USA. Univ Costa Rica, Escuela Fis, San Jose, Costa Rica. NASA, Kennedy Space Ctr, FL USA. RP Arkin, CR (reprint author), Dynacs Inc, DNX-14,POB 21087, Kennedy Space Ctr, FL 32815 USA. RI Ottens, Andrew/K-3352-2012 NR 22 TC 10 Z9 10 U1 0 U2 0 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 1044-0305 J9 J AM SOC MASS SPECTR JI J. Am. Soc. Mass Spectrom. PD AUG PY 2002 VL 13 IS 8 BP 1004 EP 1012 AR PII S1044-0305(02)00422-1 DI 10.1016/S1044-0305(02)00422-1 PG 9 WC Biochemical Research Methods; Chemistry, Analytical; Chemistry, Physical; Spectroscopy SC Biochemistry & Molecular Biology; Chemistry; Spectroscopy GA 588ME UT WOS:000177704600013 PM 12216728 ER PT J AU Lin, RF Starr, DO DeMott, PJ Cotton, R Sassen, K Jensen, E Karcher, B Liu, XH AF Lin, RF Starr, DO DeMott, PJ Cotton, R Sassen, K Jensen, E Karcher, B Liu, XH TI Cirrus Parcel Model Comparison Project. Phase 1: The critical components to simulate cirrus initiation explicitly SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID HOMOGENEOUS ICE NUCLEATION; AQUEOUS SULFURIC-ACID; WAVE-CLOUDS; FREEZING NUCLEATION; AEROSOL-PARTICLES; RELATIVE-HUMIDITY; SUPERCOOLED WATER; SOLUTION DROPLETS; CLIMATE MODELS; PARAMETERIZATION AB The Cirrus Parcel Model Comparison Project, a project of the GCSS [Global Energy and Water Cycle Experiment (GEWEX) Cloud System Studies] Working Group on Cirrus Cloud Systems, involves the systematic comparison of current models of ice crystal nucleation and growth for specified, typical, cirrus cloud environments. In Phase 1 of the project reported here, simulated cirrus cloud microphysical properties from seven models are compared for "warm'' (-40degreesC) and "cold'' (-60degreesC) cirrus, each subject to updrafts of 0.04, 0.2, and 1 m s(-1). The models employ explicit microphysical schemes wherein the size distribution of each class of particles (aerosols and ice crystals) is resolved into bins or the evolution of each individual particle is traced. Simulations are made including both homogeneous and heterogeneous ice nucleation mechanisms (all-mode simulations). A single initial aerosol population of sulfuric acid particles is prescribed for all simulations. Heterogeneous nucleation is disabled for a second parallel set of simulations in order to isolate the treatment of the homogeneous freezing (of haze droplets) nucleation process. Analysis of these latter simulations is the primary focus of this paper. Qualitative agreement is found for the homogeneous-nucleation- only simulations; for example, the number density of nucleated ice crystals increases with the strength of the prescribed updraft. However, significant quantitative differences are found. Detailed analysis reveals that the homogeneous nucleation rate, haze particle solution concentration, and water vapor uptake rate by ice crystal growth (particularly as controlled by the deposition coefficient) are critical components that lead to differences in the predicted microphysics. Systematic differences exist between results based on a modified classical theory approach and models using an effective freezing temperature approach to the treatment of nucleation. Each method is constrained by critical freezing data from laboratory studies, but each includes assumptions that can only be justified by further laboratory research. Consequently, it is not yet clear if the two approaches can be made consistent. Large haze particles may deviate considerably from equilibrium size in moderate to strong updrafts (0.2-1 m s(-1))at -60degreesC. The equilibrium assumption is commonly invoked in cirrus parcel models. The resulting difference in particle-size-dependent solution concentration of haze particles may significantly affect the ice particle formation rate during the initial nucleation interval. The uptake rate for water vapor excess by ice crystals is another key component regulating the total number of nucleated ice crystals. This rate, the product of particle number concentration and ice crystal diffusional growth rate, which is particularly sensitive to the deposition coefficient when ice particles are small, modulates the peak particle formation rate achieved in an air parcel and the duration of the active nucleation time period. The consequent differences in cloud microphysical properties, and thus cloud optical properties, between state-of-the-art models of ice crystal initiation are significant. Intermodel differences in the case of all-mode simulations are correspondingly greater than in the case of homogeneous nucleation acting alone. Definitive laboratory and atmospheric benchmark data are needed to improve the treatment of heterogeneous nucleation processes. C1 NASA, Goddard Space Flight Ctr, UMBC GEST Ctr, Lab Atmosphere, Greenbelt, MD 20771 USA. UMBC GEST Ctr, Baltimore, MD USA. Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. Univ Utah, Dept Meteorol, Salt Lake City, UT 84112 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. DLR Oberpfaffenhofen, Inst Atmospher Phys, Wessling, Germany. Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48109 USA. RP Lin, RF (reprint author), NASA, Goddard Space Flight Ctr, UMBC GEST Ctr, Lab Atmosphere, Mail Code 912, Greenbelt, MD 20771 USA. RI DeMott, Paul/C-4389-2011; Cotton, Richard/K-2175-2012; Liu, Xiaohong/E-9304-2011; Karcher, Bernd/D-5325-2014 OI DeMott, Paul/0000-0002-3719-1889; Liu, Xiaohong/0000-0002-3994-5955; Karcher, Bernd/0000-0003-0278-4980 NR 73 TC 72 Z9 73 U1 0 U2 9 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 AUG PY 2002 VL 59 IS 15 BP 2305 EP 2329 DI 10.1175/1520-0469(2002)059<2305:CPMCPP>2.0.CO;2 PG 25 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 570QU UT WOS:000176669700001 ER PT J AU Xu, YH Vani, S Jeevarajan, AS Fay, JM Taylor, TD Anderson, MM AF Xu, YH Vani, S Jeevarajan, AS Fay, JM Taylor, TD Anderson, MM TI On-line measurement of glucose in a rotating wall perfused vessel bioreactor using an amperometric glucose sensor (vol 149, pg H103, 2002) SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Correction C1 Wyle Life Sci, Houston, TX 77058 USA. CP Kelco Inc, Okmulgee, OK 74447 USA. NASA, Cellular Biotechnol Program, Houston, TX 77058 USA. RP Xu, YH (reprint author), Wyle Life Sci, Houston, TX 77058 USA. NR 1 TC 0 Z9 0 U1 1 U2 1 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 65 SOUTH MAIN STREET, PENNINGTON, NJ 08534 USA SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD AUG PY 2002 VL 149 IS 8 BP L5 EP L5 DI 10.1149/1.1496215 PG 1 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA 573DY UT WOS:000176815100065 ER PT J AU Brasunas, JC AF Brasunas, JC TI A simple etalon-stabilized visible laser diode SO MEASUREMENT SCIENCE AND TECHNOLOGY LA English DT Article DE laser diode; wavelength stabilization AB Visible laser diodes (LDs) are inexpensively available with single-transverse-mode, single-longitudinal-mode operation with a coherence length in the metre range. With constant current bias and constant operating temperature, the optical output power and operating wavelength are stable. A simple and inexpensive way is developed to maintain a constant LD temperature as the temperature of the local environment varies, by monitoring the initially changing wavelength with an external etalon and using this information to apply a heating correction to the monitor photodiode commonly integral to the LD package. The fractional wavelength stability achieved is limited by the solid etalon to 7 x 10(-6) degreesC(-1). C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP NASA, Goddard Space Flight Ctr, Code 693, Greenbelt, MD 20771 USA. RI brasunas, john/I-2798-2013 NR 5 TC 2 Z9 2 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0957-0233 EI 1361-6501 J9 MEAS SCI TECHNOL JI Meas. Sci. Technol. PD AUG PY 2002 VL 13 IS 8 BP N67 EP N71 AR PII S0957-0233(02)36421-X DI 10.1088/0957-0233/13/8/401 PG 5 WC Engineering, Multidisciplinary; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 588NG UT WOS:000177707100028 ER PT J AU Andersson, BG Wannier, PG Crawford, IA AF Andersson, BG Wannier, PG Crawford, IA TI Ultra-high-resolution observations of CH in Southern Molecular Cloud envelopes SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE ISM : individual : Chamaeleon; ISM : individual : Lupus; ISM : individual : Southern Coalsack; ISM : molecules ID DIFFUSE INTERSTELLAR CLOUDS; CO SURVEY; DARK CLOUDS; CHAMELEON-I; MILKY-WAY; HYDROGEN; LUPUS; STARS; ASSOCIATION; POLARIZATION AB We present a mini-survey of ultrahigh-resolution spectroscopy (UHRS) of CH towards three southern molecular cloud envelopes. The sightlines are selected to probe physically similar gas in different Galactic environments. With a velocity resolution of similar to0.5 km s(-1) (R =575 000) these observations resolve most kinematic components of the absorption lines. We do, however, detect one line component in the Lupus region, which is not resolved and for which an upper limit of b<0.3 km s(-1) is found. We find a correlation between distance of the absorbing gas from the Galactic mid-plane and the fractional abundance of CH. We show that this correlation can be explained as being a result of a fall-off in the ultraviolet radiation field intensity and propose that CH observations in carefully selected sightlines might allow a mapping of the variations in the interstellar radiation field. C1 Johns Hopkins Univ, Ctr Astrophys Sci, Baltimore, MD 21218 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. UCL, Dept Phys & Astron, London WC1E 6BT, England. RP Andersson, BG (reprint author), Johns Hopkins Univ, Ctr Astrophys Sci, Baltimore, MD 21218 USA. EM bg@pha.jhu.edu RI Crawford, Ian/H-7510-2012 OI Crawford, Ian/0000-0001-5661-7403 NR 53 TC 10 Z9 10 U1 0 U2 0 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD AUG PY 2002 VL 334 IS 2 BP 327 EP 337 DI 10.1046/j.1365-8711.2002.t01-1-05465.x PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 580WA UT WOS:000177258500012 ER PT J AU O'Brien, K Horne, K Hynes, RI Chen, W Haswell, CA Still, MD AF O'Brien, K Horne, K Hynes, RI Chen, W Haswell, CA Still, MD TI Echoes in x-ray binaries SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE accretion, accretion discs; binaries : close; stars : individual; Nova Sco 1994 (GRO J1655-40); ultraviolet : stars; X-rays : binaries; X-rays : stars ID GRO J1655-40; NGC-5548; BURST; MASS AB We present a method of analysing the correlated X-ray and optical/UV variability in X-ray binaries, using the observed time delays between the X-ray driving light curves and their reprocessed optical echoes. This allows us to determine the distribution of reprocessing sites within the binary. We model the time-delay transfer functions by simulating the distribution of reprocessing regions, using geometrical and binary parameters. We construct best-fitting time-delay transfer functions, showing the regions in the binary responsible for the reprocessing of X-rays. We have applied this model to observations of the soft X-ray transient GRO J1655-40. We find that the optical variability lags the X-ray variability with a mean time delay of 19.3+/-2.2 s. This means that the outer regions of the accretion disc are the dominant reprocessing site in this system. On fitting the data to a simple geometric model, we derive a best-fitting disc half-opening angle of 13.5(-2.8)(+2.1degrees), which is similar to that observed after the previous outburst by Orosz & Bailyn. This disc thickening has the effect of almost entirely shielding the companion star from irradiation at this stage of the outburst. C1 Univ St Andrews, Sch Phys & Astron, St Andrews KY16 9SS, Fife, Scotland. Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. Univ Southampton, Dept Phys & Astron, Southampton SO17 1BJ, Hants, England. Open Univ, Dept Phys & Astron, Milton Keynes MK7 6AA, Bucks, England. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Space Res Assoc, Columbia, MD USA. RP O'Brien, K (reprint author), Univ St Andrews, Sch Phys & Astron, St Andrews KY16 9SS, Fife, Scotland. NR 21 TC 43 Z9 43 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 AUG PY 2002 VL 334 IS 2 BP 426 EP 434 DI 10.1046/j.1365-8711.2002.05530.x PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 580WA UT WOS:000177258500021 ER PT J AU Rubin, RH Bhatt, NJ Dufour, RJ Buckalew, BA Barlow, MJ Liu, XW Storey, PJ Balick, B Ferland, GJ Harrington, JP Martin, PG AF Rubin, RH Bhatt, NJ Dufour, RJ Buckalew, BA Barlow, MJ Liu, XW Storey, PJ Balick, B Ferland, GJ Harrington, JP Martin, PG TI Temperature variations from Hubble Space Telescope imagery and spectroscopy of NGC 7009 SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE ISM : abundances; ISM : atoms; ISM : individual : NGC 7009; planetary nebulae : general ID OPTICAL RECOMBINATION LINES; BRIGHT RING REGION; PLANETARY-NEBULAE; CHEMICAL ABUNDANCES; ELLIPTIC PNS; O-III; EXCITATION; SPECTRUM; PHOTOIONIZATION; AXIS AB We present new Hubble Space Telescope (HST)/WFPC2 imagery and STIS long-slit spectroscopy of the planetary nebula NGC 7009. The primary goal was to obtain high spatial resolution of 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 . The WFPC2 T(e) map is rather uniform; almost all values are between 9000-11 000 K, with the higher T(e) values closely coinciding with the inner He(++) zone. The results indicate very small values-less than or similar to0.01<- for t (A) (2) throughout. Our STIS data allow an even more direct determination of T(e) and t (A) (2) , albeit for a much smaller area than with WFPC2. We present results from binning the data along the slit into tiles that are 0.5-arcsec square (matching the slit width). The average [O iii] temperature using 45 tiles (excluding the central star and STIS fiducial bars) is 10 139 K; t (A) (2) is 0.0035. 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 completely rule out temperature fluctuations along the line of sight as the cause of the large abundance discrepancy between heavy element abundances inferred from collisionally excited emission lines compared to those derived from recombination lines. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Orion Enterprises, Moffett Field, CA 94035 USA. Rice Univ, Dept Phys & Astron, Houston, TX 77005 USA. UCL, Dept Phys & Astron, London WC1E 6BT, England. Univ Washington, Dept Astron, Seattle, WA 98195 USA. Univ Kentucky, Dept Phys & Astron, Lexington, KY 40506 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. Univ Toronto, Canadian Inst Theoret Astrophys, Toronto, ON M5S 3H8, Canada. RP Rubin, RH (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM rubin@cygnus.arc.nasa.gov RI Barlow, Michael/A-5638-2009; OI Barlow, Michael/0000-0002-3875-1171; Ferland, Gary/0000-0003-4503-6333 NR 35 TC 34 Z9 34 U1 0 U2 0 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD AUG PY 2002 VL 334 IS 4 BP 777 EP 786 DI 10.1046/j.1365-8711.2002.05567.x PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 586NJ UT WOS:000177589800006 ER PT J AU Zeng, XB Zhang, Q Johnson, D Tao, WK AF Zeng, XB Zhang, Q Johnson, D Tao, WK TI Parameterization of wind gustiness for the computation of ocean surface fluxes at different spatial scales SO MONTHLY WEATHER REVIEW LA English DT Article ID TOGA COARE; GENERAL-CIRCULATION; CONVECTION; MODELS; ENHANCEMENT; PARAMETRIZATION; EVAPORATION; SENSITIVITY; SYSTEMS; PACIFIC AB Analysis of the Goddard cloud-ensemble (GCE) model output forced by observational data over the tropical western Pacific and eastern tropical North Atlantic has shown that ocean surface latent and sensible heat fluxes averaged in a typical global-model grid box are reproduced well using bulk algorithms with grid- box-average scalar wind speed but could be significantly underestimated under weak wind conditions using average vector wind speed. This is consistent with previous observational and modeling studies. The difference between scalar and vector wind speeds represents the subgrid wind variability (or wind gustiness) that is contributed by boundary layer large eddies, convective precipitation, and cloudiness. Based on the GCE data analysis for a case over the tropical western Pacific, a simple parameterization for wind gustiness has been developed that considers the above three factors. This scheme is found to fit well the GCE data for two other cases over the tropical western Pacific and eastern tropical North Atlantic. Its fit is also much better than that of the traditional approach that considers the contribution to wind gustiness by boundary layer large eddies alone. A simple formulation has also been developed to account for the dependence of the authors' parameterization on spatial scales (or model grid size). Together, the preliminary parameterization and formulation can be easily implemented into weather and climate models with various horizontal resolutions. C1 Univ Arizona, Dept Atmospher Sci, Inst Atmospher Phys, Tucson, AZ 85721 USA. Cold & Arid Reg Environm & Engn Res Inst, Lanzhou, Peoples R China. NASA, Goddard Space Flight Ctr, Mesoscale Atmospher Proc Branch, Greenbelt, MD 20771 USA. RP Zeng, XB (reprint author), Univ Arizona, Dept Atmospher Sci, Inst Atmospher Phys, POB 210081, Tucson, AZ 85721 USA. OI Zeng, Xubin/0000-0001-7352-2764 NR 31 TC 14 Z9 20 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD AUG PY 2002 VL 130 IS 8 BP 2125 EP 2133 DI 10.1175/1520-0493(2002)130<2125:POWGFT>2.0.CO;2 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 563KC UT WOS:000176254000012 ER PT J AU Lillehei, PT Park, C Rouse, JH Siochi, EJ AF Lillehei, PT Park, C Rouse, JH Siochi, EJ TI Imaging carbon nanotubes in high performance polymer composites via magnetic force microscopy SO NANO LETTERS LA English DT Article AB Application of carbon nanotubes as reinforcement in structural composites is dependent on the efficient dispersion of the nanotubes in a high performance polymer matrix. The characterization of such dispersion is limited by the lack of available tools to visualize the quality of the matrix/carbon nanotube interaction. The work reported herein demonstrates the use of magnetic force microscopy (MFM) as a promising technique for characterizing the dispersion of nanotubes in a high performance polymer matrix. C1 NASA, Langley Res Ctr, Adv Mat & Proc Branch, Hampton, VA 23681 USA. ICASE, Hampton, VA 23681 USA. RP Lillehei, PT (reprint author), NASA, Langley Res Ctr, Adv Mat & Proc Branch, Hampton, VA 23681 USA. RI Lillehei, Peter/C-9196-2009 OI Lillehei, Peter/0000-0001-8183-9980 NR 13 TC 45 Z9 45 U1 0 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1530-6984 J9 NANO LETT JI Nano Lett. PD AUG PY 2002 VL 2 IS 8 BP 827 EP 829 DI 10.1021/nl0255855 PG 3 WC Chemistry, Multidisciplinary; Chemistry, Physical; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Chemistry; Science & Technology - Other Topics; Materials Science; Physics GA 584TU UT WOS:000177485500007 ER PT J AU Weber, AL AF Weber, AL TI Chemical constraints governing the origin of metabolism: The thermodynamic landscape of carbon group transformations under mild aqueous conditions SO ORIGINS OF LIFE AND EVOLUTION OF THE BIOSPHERE LA English DT Article DE biosynthesis; free energy; metabolism; sugar chemistry; molecular evolution; prebiotic synthesis; thermodynamics ID SUGAR MODEL; EARLY EARTH; ENERGY; ATMOSPHERE; WATER; PHOTOCHEMISTRY; GLYCERALDEHYDE; FORMALDEHYDE; TEMPERATURE; REACTIVITY AB The thermodynamics of organic chemistry under mild aqueous conditions was examined in order to begin to understand its influence on the structure and operation of metabolism and its antecedents. Free energies (DeltaG) were estimated for four types of reactions of biochemical importance - carbon-carbon bond cleavage and synthesis, hydrogen transfer between carbon groups, dehydration of alcohol groups, and aldo-keto isomerization. The energies were calculated for mainly aliphatic groups composed of carbon, hydrogen, and oxygen. The energy values showed (1) that generally when carbon-carbon bond cleavage involves groups from different functional group classes (i.e., carboxylic acids, carbonyl groups, alcohols, and hydrocarbons), the transfer of the shared electron-pair to the more reduced carbon group is energetically favored over transfer to the more oxidized carbon group, and (2) that the energy of carbon-carbon bond transformation is primarily determined by the functional group class of the group that changes oxidation state in the reaction (i.e., the functional group class of the group that donates the shared electron-pair during cleavage, or that accepts the incipient shared electron-pair during synthesis). In contrast, the energy of hydrogen transfer between carbon groups is determined by the functional group class of both the hydrogen-donor group and the hydrogen-acceptor group. From these and other observations we concluded that the chemistry involved in the origin of metabolism (and to a lesser degree modern metabolism) was strongly constrained by (1) the limited redox-based transformation energy of organic substrates that is readily dissipated in a few energetically favorable irreversible reactions; (2) the energy dominance of a few transformation half-reactions that determines whether carbon-carbon bond transformation (cleavage or synthesis) is energetically favorable (DeltaG < -3.5 kcal/mol), reversible (&UDelta;G between +/- 3.5 kcal/mol), or unfavorable (&UDelta;G > +3.5 kcal/mol); and (3) the dependence of carbon group transformation energy on the functional group class (i.e., oxidation state) of participating groups that in turn is contingent on prior reactions and precursors in the synthetic pathway. C1 NASA, SETI Inst, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Weber, AL (reprint author), NASA, SETI Inst, Ames Res Ctr, Mail Stop 239-4, Moffett Field, CA 94035 USA. NR 46 TC 26 Z9 27 U1 2 U2 9 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 AUG PY 2002 VL 32 IS 4 BP 333 EP 357 DI 10.1023/A:1020588925703 PG 25 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 600LY UT WOS:000178393000006 PM 12458737 ER PT J AU Zong, J Davies, R Muller, JP Diner, DJ AF Zong, J Davies, R Muller, JP Diner, DJ TI Photogrammetric retrieval of cloud advection and top height from the multi-angle imaging spectroradiometer (MISR) SO PHOTOGRAMMETRIC ENGINEERING AND REMOTE SENSING LA English DT Article ID FEASIBILITY; SATELLITES; MOTION AB This article describes a stereo-photogrammetric method for simultaneous retrieval of cloud advection and cloud-top height fields using multi-angle imagery from the MISR instrument. Although stereoscopy has been widely used for topographic surface retrieval, its application to dynamic cloud elevations has been very limited. This article shows theoretically that, by using multiple MISR camera look angles from satellite altitudes, cloud advection and cloud-top height can be separated stereoscopically, thus enabling their simultaneous retrieval. A completely automatic retrieval algorithm was designed and implemented, including steps for multi-angle image registration on a reference Earth ellipsoid surface, mesoscale cloud advection derivation employing stereoscopic retrieval, and simultaneous stereoscopic reduction of high-resolution cloud-top heights. Before instrument launch, numerical simulations were implemented to demonstrate the feasibility of the retrieval, and to derive estimates of the algorithm errors. Since launch, stereo cloud reduction from MISR has been routinely processed for global climatological studies. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Arizona, Inst Atmospher Phys, Tucson, AZ 85721 USA. UCL, Dept Geomat Engn, London WC1E 6BT, England. RP Zong, J (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Jia.Zong@jpl.nasa.gov RI Davies, Roger/D-4296-2009 OI Davies, Roger/0000-0002-2991-0409 NR 17 TC 31 Z9 33 U1 0 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 AUG PY 2002 VL 68 IS 8 BP 821 EP 829 PG 9 WC Geography, Physical; Geosciences, Multidisciplinary; Remote Sensing; Imaging Science & Photographic Technology SC Physical Geography; Geology; Remote Sensing; Imaging Science & Photographic Technology GA 578FX UT WOS:000177107700006 ER PT J AU Choi, DI Chism, W AF Choi, DI Chism, W TI Intense field stabilization in circular polarization: Three-dimensional time-dependent dynamics SO PHYSICAL REVIEW A LA English DT Article ID ARBITRARY LASER POLARIZATIONS; ADIABATIC STABILIZATION; HIGH-FREQUENCY; SUPERINTENSE; HYDROGEN AB We investigate the stabilization of hydrogen atoms in a circularly polarized laser field. We use a three-dimensional, time-dependent approach to study the quantum dynamics of hydrogen atoms subject to high-intensity, short-wavelength, laser pulses. We find an enhanced survival probability as the field is increased under fixed envelope conditions. We also confirm wave packet behaviors previously seen in two-dimensional time-dependent computations. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Univ Texas, Ctr Studies Stat Mech & Complex Syst, Austin, TX 78712 USA. RP Choi, DI (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. NR 20 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 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD AUG PY 2002 VL 66 IS 2 AR 025401 DI 10.1103/PhysRevA.66.025401 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 591HA UT WOS:000177872600141 ER PT J AU Li, JZ Ning, CZ AF Li, JZ Ning, CZ TI Hydrodynamic theory for spatially inhomogeneous semiconductor lasers. I. A microscopic approach SO PHYSICAL REVIEW A LA English DT Article ID ELECTRON-HOLE SCATTERING; SURFACE-EMITTING LASERS; GAAS QUANTUM WELLS; EXCITED SEMICONDUCTORS; PHONON INTERACTION; CARRIER DYNAMICS; BLOCH EQUATIONS; AMPLIFIERS; PLASMA; RELAXATION AB Starting from the microscopic semiconductor Bloch equations including the Boltzmann transport terms in the distribution function equations for electrons and holes, we derived a closed set of diffusion equations for carrier densities and temperatures with self-consistent coupling to Maxwell's equation and to an effective optical polarization equation. The coherent many-body effects are included within the screened Hartree-Fock approximation, while scatterings are treated within the second Born approximation including both the in- and out-scatterings. Microscopic expressions for electron-hole (e-h) and carrier-LO-phonon (c-LO) scatterings are directly used to derive the momentum and energy relaxation rates. These rates, expressed as functions of temperatures and densities, lead to microscopic expressions for self- and mutual-diffusion coefficients in the coupled density-temperature diffusion equations. Approximations for reducing the general two-component description of the electron-hole plasma to a single-component one are discussed. In particular, we show that a special single-component reduction is possible when e-h scattering dominates over c-LO-phonon scattering. The ambipolar diffusion approximation is also discussed and we show that the ambipolar diffusion coefficients are independent of e-h scattering, even though the diffusion coefficients of individual components depend sensitively on the e-h scattering rates. Our discussions lead to deeper insights into the roles played in the single-component reduction by the electron-hole correlation in momentum space induced by scatterings and the electron-hole correlation in real space via internal static electrical field. Finally, the theory is completed by coupling the diffusion equations to the lattice temperature equation and to the effective optical polarization, which in turn couples to the laser field. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Li, JZ (reprint author), NASA, Ames Res Ctr, Mail Stop N229-1, Moffett Field, CA 94035 USA. RI Ning, C. Z./D-4699-2009 OI Ning, C. Z./0000-0003-4583-8889 NR 48 TC 12 Z9 12 U1 2 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD AUG PY 2002 VL 66 IS 2 AR 023802 DI 10.1103/PhysRevA.66.023802 PG 18 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 591HA UT WOS:000177872600104 ER PT J AU Li, JZ Ning, CZ AF Li, JZ Ning, CZ TI Hydrodynamic theory for spatially inhomogeneous semiconductor lasers. II. Numerical results SO PHYSICAL REVIEW A LA English DT Article AB We present numerical results for the diffusion coefficients (DCs) in the coupled diffusion model derived [J. Li and C. Z. Ning, preceding paper, Phys. Rev. A 66, 023802 (2002)] for a semiconductor quantum well. These include self- and mutual-diffusion coefficients in the general two-component case, as well as density- and temperature-related DCs under the single-component approximation. The results are analyzed from the viewpoint of the free Fermi gas theory with many-body effects incorporated. We discuss in detail the dependence of these DCs on densities and temperatures in order to identify different roles played by the free-carrier contributions including carrier statistics and carrier-LO-phonon scattering, and many-body corrections including band-gap renormalization and electron-hole (e-h) scattering. In the general two-component case, it is found that the self- and mutual-diffusion coefficients are determined mainly by the free-carrier contributions, but with significant many-body corrections near the transition density where carrier statistics changes from the Maxwell to the Fermi-Dirac distribution. Carrier-LO-phonon scattering is dominant at low density, whereas e-h scattering becomes important in determining their density dependence above the electron transition density. In the single-component case, it is found that many-body effects decrease the density coefficients but enhance the temperature coefficients. The modification is on the order of 10% and reaches a maximum of over 20% [C. Z. Ning and J. Li, Phys. Rev. B 65, 201305(R) (2002)] for the density coefficients. Overall, temperature elevation enhances the diffusive capability of carriers (DCs) linearly, and such an enhancement grows with density. The complete data set of various DCs as functions of carrier densities and temperatures provides necessary ingredients for future applications of the model to various spatially inhomogeneous optoelectronic devices. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Li, JZ (reprint author), NASA, Ames Res Ctr, Mail Stop N229-1, Moffett Field, CA 94035 USA. RI Ning, C. Z./D-4699-2009 OI Ning, C. Z./0000-0003-4583-8889 NR 17 TC 1 Z9 1 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD AUG PY 2002 VL 66 IS 2 AR 023803 DI 10.1103/PhysRevA.66.023803 PG 13 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 591HA UT WOS:000177872600105 ER PT J AU Liu, J Fu, LB Ou, BY Chen, SG Choi, DI Wu, B Niu, Q AF Liu, J Fu, LB Ou, BY Chen, SG Choi, DI Wu, B Niu, Q TI Theory of nonlinear Landau-Zener tunneling SO PHYSICAL REVIEW A LA English DT Article ID SCHRODINGER-EQUATION; BOSE; DYNAMICS; ATOMS AB We present a comprehensive analysis of the nonlinear Landau-Zener tunneling. We find characteristic scaling or power laws for the critical behavior that occurs as the nonlinear parameter equals to the gap of avoided crossing energy levels. For the nonlinear parameter larger than the energy gap, a closed-form solution is derived for the nonlinear tunneling probability, which is shown to be a good approximation to the exact solution for a wide range of the parameters. Finally, we discuss the experimental realization of the nonlinear model and possible observation of the scaling or power laws using a Bose-Einstein condensate in an accelerating optical lattice. C1 Univ Texas, Dept Phys, Austin, TX 78712 USA. Inst Appl Phys & Computat Math, Beijing 100088, Peoples R China. NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Greenbelt, MD 20771 USA. NASA, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Liu, J (reprint author), Univ Texas, Dept Phys, POB 8009, Austin, TX 78712 USA. RI Wu, Biao/B-3329-2008; Niu, Qian/G-9908-2013 OI Wu, Biao/0000-0001-9229-5894; NR 23 TC 181 Z9 186 U1 3 U2 26 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD AUG PY 2002 VL 66 IS 2 AR 023404 DI 10.1103/PhysRevA.66.023404 PG 7 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 591HA UT WOS:000177872600081 ER PT J AU Strekalov, DV Turlapov, A Kumarakrishnan, A Sleator, T AF Strekalov, DV Turlapov, A Kumarakrishnan, A Sleator, T TI Periodic structures generated in a cloud of cold atoms SO PHYSICAL REVIEW A LA English DT Article ID PRECISION-MEASUREMENT; WAVE INTERFEROMETRY; PHOTON RECOIL; MATTER WAVES; LIGHT; DEPOSITION; GRATINGS; FIELDS; GASES AB We have demonstrated a method of generation and real-time detection of nanostructures in a cold Rb cloud. These structures, which are periodic gratings of atomic density, appear as a result of interference of atoms diffracted by pulses of an optical standing wave of wavelength lambda. We have detected structures of period lambda/2 and lambda/4. Calculations indicate that these density gratings have period lambda/2N for integer N. While the structures with the period lambda/2 are easily detected by Bragg scattering of an optical probe beam, the shorter-period structures are not. For their detection we have developed a three-pulse echo method, in which the shorter-period gratings get converted into the structures with period lambda/2, readily detected in real time. Applications related to lithography are discussed. C1 NYU, Dept Phys, New York, NY 10003 USA. RP Strekalov, DV (reprint author), JPL, MS 300-123,4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Turlapov, Andrey/S-1786-2016 NR 33 TC 39 Z9 40 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD AUG PY 2002 VL 66 IS 2 AR 023601 DI 10.1103/PhysRevA.66.023601 PG 11 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 591HA UT WOS:000177872600090 ER PT J AU Patterson, JD Hofman, GJ Brack, JT Camerini, P Clark, J Delheij, PPJ Felawka, L Fragiacomo, E Gibson, EF Grion, N Jamieson, B Mathie, EL Meier, R Ottewell, D Peterson, RJ Raywood, K Ristinen, RA Rui, R Sevior, ME Smith, GR Tacik, R Tagliente, G Wagner, GJ Yeomans, DM AF Patterson, JD Hofman, GJ Brack, JT Camerini, P Clark, J Delheij, PPJ Felawka, L Fragiacomo, E Gibson, EF Grion, N Jamieson, B Mathie, EL Meier, R Ottewell, D Peterson, RJ Raywood, K Ristinen, RA Rui, R Sevior, ME Smith, GR Tacik, R Tagliente, G Wagner, GJ Yeomans, DM TI Analyzing powers for pi p elastic scattering between 57 and 139 MeV SO PHYSICAL REVIEW C LA English DT Article ID SPECTROMETER AB Analyzing powers for pip elastic scattering at bombarding energies below the Delta(1232) resonance were measured at TRIUMF using the CHAOS spectrometer and a polarized spin target. This work presents pi(-) data at six incident energies of 57, 67, 87, 98, 117, and 139 MeV, and a single pi(+) data set at 139 MeV. The higher energy measurements cover an angular range of 72degreesless than or equal totheta(c.m.)less than or equal to180degrees while the lower energies were limited to 101degreesless than or equal totheta(c.m.)less than or equal to180degrees. There is a high degree of consistency between this work and the predictions of the VPI/GWU group's SM95 partial wave analysis. C1 Univ Colorado, Boulder, CO 80309 USA. TRIUMF, Vancouver, BC V6T 2A3, Canada. Univ British Columbia, Dept Phys & Astron, Vancouver, BC V6T 2A6, Canada. Ist Nazl Fis Nucl, I-34127 Trieste, Italy. Univ Trieste, Dipartmento Fis, I-34127 Trieste, Italy. Univ Regina, Regina, SK S4S 0A2, Canada. Calif State Univ Sacramento, Sacramento, CA 95819 USA. Univ Melbourne, Sch Phys, Parkville, Vic 3052, Australia. Univ Tubingen, Inst Phys, D-72076 Tubingen, Germany. RP Patterson, JD (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 22 TC 1 Z9 1 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD AUG PY 2002 VL 66 IS 2 AR 025207 DI 10.1103/PhysRevC.66.025207 PG 9 WC Physics, Nuclear SC Physics GA 592CV UT WOS:000177919900074 ER PT J AU Nelson, RM Smythe, WD Hapke, BW Hale, AS AF Nelson, RM Smythe, WD Hapke, BW Hale, AS TI Low phase angle laboratory studies of the opposition effect: search for wavelength dependence SO PLANETARY AND SPACE SCIENCE LA English DT Article ID OUTER PLANET SATELLITES; COHERENT BACKSCATTER; POLARIZATION; SURGE AB We measured the reflectance change with phase angle (0.05degrees < theta < 5degrees) of 13 well-sorted particulate samples of aluminum oxide. The size of the particle fractions included sizes very much larger and very much smaller than the wavelength,;., of the incident radiation, The measurements were made at lambda = 0.633 and 0.543 mum. We searched for changes with respect to wavelength in size of the half-width at half-maximum (HWHM) of the phase curve for each particle size. These changes in HWHM are predicted theoretically and observed experimentally in scattering measurements of widely spaced spherical particles in suspension. We find that at both wavelengths the materials exhibit opposition brightness surges of similar to30% at 0.05degrees relative to the brightness at 5degrees. At both wavelengths, and for all particle sizes, the slope of the phase curve and the circular polarization ratio both increase with decreasing phase angle, consistent with the opposition surge being due to the coherent backscattering opposition effect (CBOE). Theoretical models of CBOE predict that the HWHM of the phase curve will vary with lambda, as lambda/2piL, where L is the transport mean free path in the medium. Our samples were observed at two different wavelengths, therefore theory predicts that HWHM would be smaller by about 15% at 0,543 mum compared to 0.633 mum. We do not observe this. There may be several possible explanations. One possibility is that the particles, while well sorted, nevertheless have a variance about a mean size and therefore the change in HWHM is not as sharp as might be expected were all the particles exactly of the same size. Another possible explanation is that our particles are more closely packed and less spherical than those studied in the experimental observations of particles in suspension and hence, while our experiment more closely approximates a planetary regolith, it produces a different result from similar measurements of widely spaced spherical particles in suspension. Our result may explain the unsuccessful Clementine search for CBOE in the lunar regolith which found only a very small wavelength dependence of the phase curve of the same lunar regions when observed at different wavelengths, a result not consistent with theoretical models of CBOE. One explanation may be that the particle size variation in the lunar soil is greater than it was in our samples. Furthermore, our samples, which are better sorted than the lunar regolith, are less well sorted than the theoretical models. This suggests that measuring the change in phase curve HWHM with lambda may not be a good test for CBOE in a planetary regolith unless the measurements include a large range of wavelength. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Pittsburgh, Pittsburgh, PA 15260 USA. RP Nelson, RM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 11 TC 28 Z9 28 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 AUG PY 2002 VL 50 IS 9 BP 849 EP 856 AR PII S0032-0633(02)00059-4 DI 10.1016/S0032-0633(02)00059-4 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 614TV UT WOS:000179207600005 ER PT J AU Mallama, A Degnan, JJ AF Mallama, A Degnan, JJ TI A thermal infrared cloud-mapping instrument for observatories SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article AB A thermal infrared imager for mapping the changing cloud cover over a ground-based observing site has been developed. The two main components to our instrument are a 10 gm detector that produces a 120 x 120 pixel thermogram and a convex electroplated reflector, which is situated underneath the detector and in its field of view. The resulting image covers the sky from zenith down to about 10degrees elevation. Atmospheric transparency is distinguished by the difference between the sky temperature and the ambient air temperature at ground level. Clear sky is indicated by pixels that are more than 20degreesC cooler than ambient. The qualitative results "clear, haze, and cloud" have proved to be very reliable during 2 years of development and testing. This information will be very useful to observers taking photometric, photographic, and spectroscopic data at optical wavelengths. The instrument can distinguish between different degrees of cloud opacity as a result of a new and more sophisticated data-processing algorithm. Advances in infrared technology including uncooled detectors and area imaging have also made our instrument easier to use, more versatile, and faster to acquire data than previous cloud imaging detectors. C1 Raytheon ITSS, Lanham, MD 20706 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Mallama, A (reprint author), Raytheon ITSS, 4400 Forbes Blvd, Lanham, MD 20706 USA. NR 7 TC 3 Z9 3 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6280 J9 PUBL ASTRON SOC PAC JI Publ. Astron. Soc. Pac. PD AUG PY 2002 VL 114 IS 798 BP 913 EP 917 DI 10.1086/341714 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 574PE UT WOS:000176898100011 ER PT J AU Matsu'ura, M Mora, P Donnellan, A Yin, XC AF Matsu'ura, M Mora, P Donnellan, A Yin, XC TI Earthquake processes: Physical modelling, numerical simulation and data analysis - Part I SO PURE AND APPLIED GEOPHYSICS LA English DT Article C1 Univ Tokyo, Dept Earth & Planetary Sci, Bunkyo Ku, Tokyo 1130033, Japan. Univ Queensland, Dept Earth Sci, QUAKES, Brisbane, Qld 4072, Australia. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. China Acad Sci, Inst Mech, Lab Nonlinear Mech, Beijing 100080, Peoples R China. RP Matsu'ura, M (reprint author), Univ Tokyo, Dept Earth & Planetary Sci, Bunkyo Ku, Tokyo 1130033, Japan. NR 3 TC 1 Z9 1 U1 0 U2 0 PU BIRKHAUSER VERLAG AG PI BASEL PA VIADUKSTRASSE 40-44, PO BOX 133, CH-4010 BASEL, SWITZERLAND SN 0033-4553 J9 PURE APPL GEOPHYS JI Pure Appl. Geophys. PD AUG PY 2002 VL 159 IS 9 BP 1905 EP 1907 DI 10.1007/s00024-002-8714-y PG 3 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 587UZ UT WOS:000177662900001 ER PT J AU Drake, JB Dubayah, RO Knox, RG Clark, DB Blair, JB AF Drake, JB Dubayah, RO Knox, RG Clark, DB Blair, JB TI Sensitivity of large-footprint lidar to canopy structure and biomass in a neotropical rainforest SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID REGENERATING TROPICAL FOREST; FOLIAGE-HEIGHT PROFILES; LANDSAT TM DATA; LASER ALTIMETER; SPATIAL HETEROGENEITY; STAND CHARACTERISTICS; LIGHT TRANSMITTANCE; ABOVEGROUND BIOMASS; DECIDUOUS FORESTS; RADAR BACKSCATTER AB Accurate estimates of the total biomass in terrestrial vegetation are important I-or carbon dynamics Studies at a variety of scales. Although aboveground biomass is difficult to quantify over large areas using traditional techniques, lidar remote sensing holds great promise for biomass estimation because it directly measures components of canopy Structure such as canopy height and the vertical distribution of intercepted canopy surfaces. In this study, our primary goal was to explore the sensitivity of lidar to differences in canopy structure and aboveground biomass in a dense, neotropical rainforest. We first examined the relationship between simple vertical canopy profiles derived from field measurements and the estimated aboveground biomass (EAGB) across a range of field plots located in primary and secondary tropical rainforest and in agroforesty areas. We found that metrics from field-derived vertical canopy profiles arc highly Correlated (R-2 up to .94) with EAGB across the entire range of conditions sampled. Next, we found that vertical canopy profiles from a large-footprint lidar instrument were closely related with coincident field profiles, and that metrics from both field and lidar profiles are highly correlated. As a result. metrics from lidar profiles are also highly correlated (R-2 up to .94) with EAGB across this neotropical landscape. These results help to explain the nature of the relationship between lidar data and EAGB, and also lay the foundation to explore the generality of the relationship between vertical canopy profiles and biomass in other tropical regions. (C) 2002 Elsevier Science Inc. All rights reserved. C1 Univ Maryland, Dept Geog, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. Univ Missouri, Dept Biol, St Louis, MO 63121 USA. La Selva Biol Stn, Puerto Viejo De Sarapiqu, Costa Rica. NASA, Goddard Space Flight Ctr, Laser Remote Sensing Branch, Terr Phys Lab, Greenbelt, MD 20771 USA. RP Drake, JB (reprint author), Univ Maryland, Dept Geog, College Pk, MD 20742 USA. RI Knox, Robert/E-9657-2011; Blair, James/D-3881-2013; Beckley, Matthew/D-4547-2013 NR 44 TC 159 Z9 167 U1 6 U2 47 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 AUG PY 2002 VL 81 IS 2-3 BP 378 EP 392 AR PII S0034-4257(02)00013-5 DI 10.1016/S0034-4257(02)00013-5 PG 15 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 579AJ UT WOS:000177153000018 ER PT J AU Prospero, JM Ginoux, P Torres, O Nicholson, SE Gill, TE AF Prospero, JM Ginoux, P Torres, O Nicholson, SE Gill, TE TI Environmental characterization of global sources of atmospheric soil dust identified with the Nimbus 7 Total Ozone Mapping Spectrometer (TOMS) absorbing aerosol product SO REVIEWS OF GEOPHYSICS LA English DT Review DE mineral dust; aerosols; TOMS; remote sensing; soils ID LAST GLACIAL MAXIMUM; THRESHOLD FRICTION VELOCITY; NORTH-ATLANTIC OCEAN; LAKE CHAD BASIN; OWENS DRY LAKE; MINERAL DUST; SAHARAN DUST; OPTICAL-THICKNESS; UNITED-STATES; WIND EROSION AB We use the Total Ozone Mapping Spectrometer (TOMS) sensor on the Nimbus 7 satellite to map the global distribution of major atmospheric dust sources with the goal of identifying common environmental characteristics. The largest and most persistent sources are located in the Northern Hemisphere, mainly in a broad "dust belt" that extends from the west coast of North Africa, over the Middle East, Central and South Asia, to China. There is remarkably little large-scale dust activity outside this region. In particular, the Southern Hemisphere is devoid of major dust activity. Dust sources, regardless of size or strength, can usually be associated with topographical lows located in arid regions with annual rainfall under 200-250 mm. Although the source regions themselves are arid or hyperarid, the action of water is evident from the presence of ephemeral streams, rivers, lakes, and playas. Most major sources have been intermittently flooded through the Quaternary as evidenced by deep alluvial deposits. Many sources are associated with areas where human impacts are well documented, e. g., the Caspian and Aral Seas, Tigris-Euphrates River Basin, southwestern North America, and the loess lands in China. Nonetheless, the largest and most active sources are located in truly remote areas where there is little or no human activity. Thus, on a global scale, dust mobilization appears to be dominated by natural sources. Dust activity is extremely sensitive to many environmental parameters. The identification of major sources will enable us to focus on critical regions and to characterize emission rates in response to environmental conditions. With such knowledge we will be better able to improve global dust models and to assess the effects of climate change on emissions in the future. It will also facilitate the interpretation of the paleoclimate record based on dust contained in ocean sediments and ice cores. C1 Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Miami, FL 33149 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21250 USA. Florida State Univ, Dept Meteorol, Tallahassee, FL 32306 USA. Texas Tech Univ, Dept Civil Engn, Lubbock, TX 79409 USA. Texas Tech Univ, Dept Geosci, Lubbock, TX 79409 USA. RP Prospero, JM (reprint author), Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, 4600 Rickenbacker Causeway, Miami, FL 33149 USA. EM jprospero@rsmas.miami.edu; ginoux@rondo.gsfc.nasa.gov; torres@tparty.gsfc.nasa.gov; sen@huey.met.fsu.edu; tom.gill@ttu.edu RI Ginoux, Paul/C-2326-2008; Torres, Omar/G-4929-2013; OI Ginoux, Paul/0000-0003-3642-2988; Prospero, Joseph/0000-0003-3608-6160 NR 171 TC 1167 Z9 1197 U1 34 U2 183 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 8755-1209 EI 1944-9208 J9 REV GEOPHYS JI Rev. Geophys. PD AUG-SEP PY 2002 VL 40 IS 1 AR 1002 DI 10.1029/2000RG000095 PG 31 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 638MH UT WOS:000180574400003 ER PT J AU Gaston, MJ Houwing, AFP Mudford, NR Danehy, PM Fox, JS AF Gaston, MJ Houwing, AFP Mudford, NR Danehy, PM Fox, JS TI Fluorescence imaging of mixing flowfields and comparisons with computational fluid dynamic simulations SO SHOCK WAVES LA English DT Article DE computational flow imaging; hypermixing; scramjet; planar laser induced fluorescence; computational fluid dynamics ID LASER-INDUCED FLUORESCENCE; SHEAR-LAYER AB This paper compares computational and experimental fluorescence images of the mixing flows associated with a number of fuel injectors injecting hydrogen fuel into a supersonic coflow The favourable comparison allows us to establish the reliability of the computational fluid dynamic modelling on which the theoretical images are based Theoretical calculations of mixing performance parameters are then used to assess the mixing characteristics and performance of the injectors. C1 Australian Natl Univ, Dept Phys & Theoret Phys, Aerophys & Laser Based Diagnost Res Lab, Canberra, ACT 0200, Australia. NASA, Langley Res Ctr, Instrumentat Syst Dev Branch, Hampton, VA 23681 USA. Univ Coll UNSW, Australian Def Force Acad, Sch Aerosp & Mech Engn, Canberra, ACT 2600, Australia. Univ Technol Sydney, Fac Engn, Broadway, NSW 2007, Australia. RP Houwing, AFP (reprint author), Australian Natl Univ, Dept Phys & Theoret Phys, Aerophys & Laser Based Diagnost Res Lab, Canberra, ACT 0200, Australia. NR 17 TC 3 Z9 3 U1 0 U2 0 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0938-1287 J9 SHOCK WAVES JI Shock Waves PD AUG PY 2002 VL 12 IS 2 BP 99 EP 110 DI 10.1007/s0019300201514 PG 12 WC Mechanics SC Mechanics GA 589AK UT WOS:000177735200002 ER PT J AU Li, W Huyse, L Padula, S AF Li, W Huyse, L Padula, S TI Robust airfoil optimization to achieve drag reduction over a range of Mach numbers SO STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION LA English DT Article DE robust optimization; airfoil shape optimization; consistent drag reduction; lift-constrained drag minimization; adaptive weight adjustment ID UNSTRUCTURED GRIDS; SHAPE OPTIMIZATION; TURBULENT FLOWS; DESIGN AB An airfoil shape optimization method that reduces drag over a range of free stream Mach numbers is sought. We show that one acceptable choice is a weighted multipoint optimization method using more design points than there are free-design variables. Alternate methods that use far fewer design points are explored. A new method called profile optimization is developed and analyzed. This method has three main advantages: (a) it prevents severe degradation at the off-design points by using a smart descent direction, (b) there is no random airfoil shape distortion for any iterate it generates, and (c) it is not sensitive to the number of design points. For illustration purposes, we use the profile optimization method to solve a lift-constrained drag minimization problem for 2-D airfoil in Euler flow with 20 free-design variables. A comparison with other airfoil optimization methods is also included. C1 Old Dominion Univ, Dept Math & Stat, Norfolk, VA 23529 USA. NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. NASA, Langley Res Ctr, Multidisciplinary Optimizat Branch, Hampton, VA 23681 USA. RP Li, W (reprint author), Old Dominion Univ, Dept Math & Stat, Norfolk, VA 23529 USA. NR 21 TC 40 Z9 40 U1 1 U2 11 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 1615-147X J9 STRUCT MULTIDISCIP O JI Struct. Multidiscip. Optim. PD AUG PY 2002 VL 24 IS 1 BP 38 EP 50 DI 10.1007/s00158-002-0212-4 PG 13 WC Computer Science, Interdisciplinary Applications; Engineering, Multidisciplinary; Mechanics SC Computer Science; Engineering; Mechanics GA 591QV UT WOS:000177892500004 ER PT J AU Griffin, TP Breznik, GS Mizell, CA Helms, WR Naylor, GR Haskell, WD AF Griffin, TP Breznik, GS Mizell, CA Helms, WR Naylor, GR Haskell, WD TI A fully-redundant, on-line, mass-spectrometer system used to monitor cryogenic fuel leaks on the Space Shuttle SO TRAC-TRENDS IN ANALYTICAL CHEMISTRY LA English DT Article DE gas monitoring; leak monitoring; on-line mass spectrometry; process mass spectrometry; real-time monitoring; Space Shuttle AB An on-line, gas-monitoring system was developed to replace the older systems used to monitor for cryogenic leaks on the Space Shuttles before launch. The new system uses a mass spectrometer to monitor multiple locations on the Orbiter. The results of performance tests are reported in this article. (C) 2002 Published by Elsevier Science B.V. All rights reserved. C1 NASA, Kennedy Space Ctr, FL 32899 USA. Dynacs Inc, Kennedy Space Ctr, FL 32899 USA. RP Griffin, TP (reprint author), YA-F2-C, Kennedy Space Ctr, FL 32899 USA. NR 6 TC 5 Z9 5 U1 1 U2 1 PU ELSEVIER SCIENCE LONDON PI LONDON PA 84 THEOBALDS RD, LONDON WC1X 8RR, ENGLAND SN 0165-9936 J9 TRAC-TREND ANAL CHEM JI Trac-Trends Anal. Chem. PD AUG PY 2002 VL 21 IS 8 BP 488 EP 497 AR PII S0165-9936(02)00703-3 DI 10.1016/S0165-9936(02)00703-3 PG 10 WC Chemistry, Analytical SC Chemistry GA 586BE UT WOS:000177561600015 ER PT J AU Diaz, JA Vargas, AEM Diaz, FC Squire, JP Jacobson, V McCaskill, G Rohrs, H Chhatwal, R AF Diaz, JA Vargas, AEM Diaz, FC Squire, JP Jacobson, V McCaskill, G Rohrs, H Chhatwal, R TI Test of a miniature double-focusing mass spectrometer for real-time plasma monitoring SO TRAC-TRENDS IN ANALYTICAL CHEMISTRY LA English DT Article ID SECTOR AB A miniature double-focusing mass spectrometer with an 8 mm radius was tested at the Advanced Space Propulsion Laboratory (ASPL) at NASA Johnson Space Center (JSC). The purpose of these experiments was to provide residual gas-analysis and single-ion-monitoring capabilities for the vacuum chamber where NASA's new plasma propulsion system, the Variable Specific Impulse Magnetoplasma Rocket (VASIMR), is being developed. The instrument used here was an alpha (alpha) version of the Integrated Leak Detector System (ILD 50) and represents a smaller version of the original 20 mm-radius Compact Double Focusing Mass Spectrometer prototype (CDFMS) developed at the University of Minnesota. The instrument successfully provided gas-composition information on the vacuum test chamber and several different plasma formulations, provided resolving powers close to the theoretical value of 40 at full width half maximum (FWHM) and demonstrated an operational mass range of 1-50 Da. (C) 2002 Published by Elsevier Science B.V. All rights reserved. C1 Univ Costa Rica, Escuela Fis, San Jose, Costa Rica. Ctr Nacl Alta Tecnol, CENAT, San Jose, CA USA. NASA, Lyndon B Johnson Space Ctr, Adv Space Prop Lab, Houston, TX 77058 USA. Mass Sensors Inc, St Louis, MO USA. RP Diaz, JA (reprint author), Univ Costa Rica, Escuela Fis, San Jose, Costa Rica. NR 27 TC 4 Z9 4 U1 1 U2 4 PU ELSEVIER SCIENCE LONDON PI LONDON PA 84 THEOBALDS RD, LONDON WC1X 8RR, ENGLAND SN 0165-9936 J9 TRAC-TREND ANAL CHEM JI Trac-Trends Anal. Chem. PD AUG PY 2002 VL 21 IS 8 BP 515 EP 525 AR PII S0165-9936(02)00705-7 DI 10.1016/S0165-9936(02)00705-7 PG 11 WC Chemistry, Analytical SC Chemistry GA 586BE UT WOS:000177561600017 ER PT J AU Simpson, JJ Hufford, GL Pieri, D Servranckx, R Berg, JS Bauer, C AF Simpson, JJ Hufford, GL Pieri, D Servranckx, R Berg, JS Bauer, C TI The February 2001 eruption of Mount Cleveland, Alaska: Case study of an aviation hazard SO WEATHER AND FORECASTING LA English DT Article ID SATELLITE-BASED TECHNIQUE; DETECTING VOLCANIC ASH; FAILURES AB Mount Cleveland, Alaska (52degrees49'N, 169degrees57'W), located on Chuginadak Island, erupted on 19 February 2001. The atmosphere-volcanic plume interactions that occurred as part of this event led to several serious encounters of commercial aircraft with the ash. A number of continental and oceanic air traffic control areas were affected. Here, a detailed case study of the eruption, subsequent movement of the airborne plume, and operational response is presented. The likelihood of such encounters in the future may be reduced as a result of lessons learned from this event. Some potential new assets for improving the detection of and response to the airborne volcanic ash hazard to aviation also are discussed. C1 Univ Calif San Diego, Digital Image Anal Lab, La Jolla, CA 92093 USA. NOAA, Natl Weather Serv Alaska Reg, Anchorage, AK USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. Meteorol Serv Canada, Canadian Meteorol Ctr, Montreal, PQ, Canada. RP Simpson, JJ (reprint author), Univ Calif San Diego, Digital Image Anal Lab, 9500 Gilman Dr, La Jolla, CA 92093 USA. NR 28 TC 35 Z9 36 U1 1 U2 4 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 AUG PY 2002 VL 17 IS 4 BP 691 EP 704 DI 10.1175/1520-0434(2002)017<0691:TFEOMC>2.0.CO;2 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 574NY UT WOS:000176897500004 ER PT J AU Sallenger, AH Krabill, W Brock, J Swift, R Manizade, S Stockdon, H AF Sallenger, AH Krabill, W Brock, J Swift, R Manizade, S Stockdon, H TI Sea-cliff erosion as a function of beach changes and extreme wave runup during the 1997-1998 El Nino SO MARINE GEOLOGY LA English DT Article DE erosion; beaches; El Nino; sea cliffs ID CALIFORNIA; COAST AB Over time scales of hundreds to thousands of years, the net longshore sand transport direction along the central California coast has been driven to the south by North Pacific winter swell. In contrast, during the El Nino winter of 1997-1998, comparisons of before and after airborne lidar surveys showed sand was transported from south to north and accumulated on the south sides of resistant headlands bordering pocket beaches. This resulted in significant beach erosion at the south ends of pocket beaches and deposition in the north ends. Coincident with the south-to-north redistribution of sand, shoreline morphology became prominently cuspate with longshore wavelengths of 400-700 m. The width and elevation of beaches were least where maximum shoreline erosion occurred, preferentially exposing cliffs to wave attack. The resulting erosional hotspots typically were located in the embayments of giant cusps in the southern end of the pocket beaches. The observed magnitude of sea cliff retreat, which reached 14 m, varied with the number of hours that extreme wave runup exceeded certain thresholds representing the protective capacity of the beach during the El Nino winter. A threshold representing the width of the beach performed better than a threshold representing the elevation of the beach. The magnitude of cliff erosion can be scaled using a simple model based on the cross-shore distance that extreme wave runup exceeded the pre-winter cliff position. Cliff erosion appears to be a balance between terrestrial mass wasting processes, which tend to decrease the cliff slope, and wave attack, which removes debris and erodes the cliff base increasing the cliff slope. (C) 2002 Elsevier Science B.V. All rights reserved. C1 US Geol Survey, Ctr Coastal Geol, St Petersburg, FL 33701 USA. NASA, Wallops Flight Facil, GSFC, Wallops Isl, VA USA. GSFC, EG & G, Wallops Flight Facil, Wallops Isl, VA USA. RP Sallenger, AH (reprint author), US Geol Survey, Ctr Coastal Geol, 600 4th St S, St Petersburg, FL 33701 USA. OI Stockdon, Hilary/0000-0003-0791-4676 NR 43 TC 67 Z9 69 U1 0 U2 9 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0025-3227 J9 MAR GEOL JI Mar. Geol. PD JUL 30 PY 2002 VL 187 IS 3-4 BP 279 EP 297 AR PII S0025-3227(02)00316-X DI 10.1016/S0025-3227(02)00316-X PG 19 WC Geosciences, Multidisciplinary; Oceanography SC Geology; Oceanography GA 588EK UT WOS:000177688200004 ER PT J AU Nguyen, CV Stevens, RMD Barber, J Han, J Meyyappan, M Sanchez, MI Larson, C Hinsberg, WD AF Nguyen, CV Stevens, RMD Barber, J Han, J Meyyappan, M Sanchez, MI Larson, C Hinsberg, WD TI Carbon nanotube scanning probe for profiling of deep-ultraviolet and 193 nm photoresist patterns SO APPLIED PHYSICS LETTERS LA English DT Article ID MICROSCOPY; RESOLUTION; CATALYSTS; GROWTH; TIPS AB The continual scaling down of complementary metal-oxide semiconductor feature size to 100 nm and below necessitates a characterization technique to resolve high-aspect-ratio features in the nanoscale regime. We report the use of atomic force microscopy coupled with high-aspect-ratio multiwalled carbon nanotube (MWCNT) scanning probe tip for the purpose of imaging surface profile of photoresists. MWCNT tips of 5-10 nm in diameter and about a micron long are used. Their exceptional mechanical strength and ability to buckle reversibly enable resolution of steep, deep nanoscale features. Images of photoresist patterns generated by 257 nm interference lithography as well as 193 nm lithography are presented to demonstrate MWCNT scanning probe tips for applications in metrology. (C) 2002 American Institute of Physics. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. IBM Corp, Almaden Res Ctr, San Jose, CA 95120 USA. ELORET Corp, Sunnyvale, CA 94087 USA. RP Nguyen, CV (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 13 TC 47 Z9 47 U1 1 U2 3 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUL 29 PY 2002 VL 81 IS 5 BP 901 EP 903 DI 10.1063/1.1496139 PG 3 WC Physics, Applied SC Physics GA 576MK UT WOS:000177008900039 ER PT J AU Li, J Stevens, R Delzeit, L Ng, HT Cassell, A Han, J Meyyappan, M AF Li, J Stevens, R Delzeit, L Ng, HT Cassell, A Han, J Meyyappan, M TI Electronic properties of multiwalled carbon nanotubes in an embedded vertical array SO APPLIED PHYSICS LETTERS LA English DT Article ID TRANSISTORS; MICROSCOPY AB We demonstrate integration of carbon nanotubes into large scale vertically aligned electrode arrays, by filling the as-grown samples with conformal SiO2 using chemical vapor deposition. Subsequent mechanical polishing yields a flat surface with only the very ends of the nanotube array exposed. The electronic properties of individual carbon nanotubes in the array are measured using current-sensing atomic force microscopy. These vertical nanotube arrays are suitable for fabricating various electronic devices and sensors. (C) 2002 American Institute of Physics. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. ELORET Corp, Sunnyvale, CA 94087 USA. SETI Inst, Moffett Field, CA USA. RP Li, J (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RI Li, Jun/H-7771-2013 OI Li, Jun/0000-0002-3689-8946 NR 22 TC 126 Z9 127 U1 1 U2 26 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUL 29 PY 2002 VL 81 IS 5 BP 910 EP 912 DI 10.1063/1.1496494 PG 3 WC Physics, Applied SC Physics GA 576MK UT WOS:000177008900042 ER PT J AU Rogers, MM AF Rogers, MM TI The evolution of strained turbulent plane wakes SO JOURNAL OF FLUID MECHANICS LA English DT Article ID NAVIER-STOKES EQUATIONS; MIXING LAYER; UNIFORM DISTORTION; PRESSURE-GRADIENT; DIRECT SIMULATION; SELF-SIMILARITY; BOUNDARY-LAYER; CROSS-SHEAR; FLOW; CONTRACTION AB Direct numerical simulations of ten turbulent time-evolving strained wakes have been generated using a pseudo-spectral numerical method. In all the simulations, the strain was applied to the same (previously generated) initial developed self-similar wake flow field. The cases include flows in which the wake is subjected to various orientations of the applied mean strain, including both plane and axisymmetric strain configurations. In addition, for one particular strain geometry, cases with differing strain rates were considered. Although classical self-similar analysis does yield a self-similar solution for strained wakes, this solution does not describe the observed flow evolution. Instead, the wake mean velocity profiles evolve according to a different 'equilibrium similarity solution', with the strained wake width being determined by the straining in the inhomogeneous cross-stream direction. Wakes that are compressed in this direction eventually exhibit constant widths, whereas wakes in cases with expansive cross-stream strain ultimately spread at the same rate as the distortion caused by the applied strain. The shape of the wake mean velocity deficit profile is nearly universal. Although the effect of the strain on the mean flow is pronounced and rapid, the response of the turbulence to the strain occurs more slowly. Changes in the turbulence intensity cannot keep pace with changes in the mean wake velocity deficit, even for relatively low strain rates. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Rogers, MM (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 42 TC 18 Z9 18 U1 0 U2 0 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 32 AVENUE OF THE AMERICAS, NEW YORK, NY 10013-2473 USA SN 0022-1120 J9 J FLUID MECH JI J. Fluid Mech. PD JUL 25 PY 2002 VL 463 BP 53 EP 120 DI 10.1017/S0022112002008686 PG 68 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 584PE UT WOS:000177475400003 ER PT J AU Shariff, K Wray, A AF Shariff, K Wray, A TI Analysis of the radar reflectivity of aircraft vortex wakes SO JOURNAL OF FLUID MECHANICS LA English DT Article ID VORTICES; INSTABILITY; TURBULENCE; TRANSPORT; FLUID; PAIR; AIR AB Radar has been proposed as a way of tracking wake vortices to reduce aircraft spacing and tests have revealed radar echoes from aircraft wakes in clear air. The mechanism causing refractive index gradients in these tests is thought to be the same as that for homogeneous and isotropic atmospheric turbulence in the Kolmogorov inertial range, for which there is a scattering analysis due to Tatarski. In reality, however, the structure of aircraft wakes has a significant coherent part superimposed with turbulence, about whose structure very little is known. This work adopts a picture of a coherent (in fact two-dimensional) wake to perform a scattering analysis and calculate the reflected power. In particular, two simple mechanisms causing refractive index gradients are considered: (A) radial pressure (and therefore density) gradient in a columnar vortex arising from the rotational flow; (B) adiabatic transport of atmospheric fluid within a descending oval surrounding a vortex pair. In the scattering analysis, Tatarski's weak scattering approximation is kept but the usual assumptions of a far field and a uniform incident wave are dropped. Neither assumption is generally valid for a wake that is coherent across the radar beam. For analytical insight, an approximate analysis that invokes, in addition to weak scattering, the far-field and wide cylindrical beam assumptions, is also developed and compared with the more general analysis. Reflectivities calculated for the oval (mechanism B) are within 2-13 dB m(2) of the measurements (approximate to -70 dB m(2)) of MIT Lincoln Laboratory at Kwajalein atoll. However, the present predictions have a cut-off away from normal incidence which is not present in the measurements. This implies that the two-dimensional picture is not entirely complete. Estimates suggest that the thin layer of vorticity which is baroclinically generated at the boundary of the oval is turbulent and this may account for reflectivity away from normal incidence. The reflectivity of a vortex (mechanism A) is comparable to that of the oval (mechanism B) but occurs at a frequency (about 50 MHz) that is lower than those considered in all the experiments to date. This result may be useful because: (i) existing atmospheric radars (known as ST radars) already operate at this frequency and so the present prediction could be verified; (ii) rain clutter is not a problem at this frequency; (iii) mechanism A is more robust because it is independent of atmospheric stratification. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Shariff, K (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. OI Shariff, Karim/0000-0002-7256-2497 NR 50 TC 24 Z9 39 U1 0 U2 1 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH ST, NEW YORK, NY 10011-4221 USA SN 0022-1120 J9 J FLUID MECH JI J. Fluid Mech. PD JUL 25 PY 2002 VL 463 BP 121 EP 161 DI 10.1017/S0022112002008674 PG 41 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 584PE UT WOS:000177475400004 ER PT J AU Zaman, KBMQ Dahl, MD Bencic, TJ Loh, CY AF Zaman, KBMQ Dahl, MD Bencic, TJ Loh, CY TI Investigation of a 'transonic resonance' with convergent-divergent nozzles SO JOURNAL OF FLUID MECHANICS LA English DT Article ID DIFFUSER FLOW; JET; OSCILLATIONS; NOISE AB Experimental studies have shown that convergent-divergent nozzles, when run at low pressure ratios, often undergo a flow resonance accompanied by emission of acoustic tones. The phenomenon, different in characteristics from conventional 'screech' tones, is addressed in this paper. Unlike screech, the resonant frequency (f(N)) increases with increasing supply pressure. There is a 'staging' behaviour; odd-harmonic stages resonate at lower pressures while the fundamental occurs in a wide range of higher pressures corresponding to a 'fully expanded Mach number' (M-j) around unity. Within a stage, f(N) varies approximately linearly with M-j; the slope of the variation steepens when the angle of divergence of the nozzle is decreased. Based on the data, correlation equations are provided for the prediction of f(N). A companion computational study captures the phenomenon and predicts the frequencies, including the stage jump, quite well. While the underlying mechanisms are not completely understood yet, it is clear that the unsteadiness of a shock occurring within the divergent section plays a direct role. The shock drives the flow downstream like a vibrating diaphragm, and resonance takes place similarly to the (no-flow) acoustic resonance of a conical section having one end closed and the other end open. Thus, the fundamental is accompanied by a standing one-quarter wave within the divergent section, the next stage by a standing three-quarter wave, and so on. The distance from the foot of the shock to the nozzle exit imposes the pertinent length scale. The principal trends in the frequency variation are explained qualitatively from the characteristic variation of that length scale. A striking feature is that tripping of the nozzle's internal boundary layer tends to suppress the resonance. It is likely that the trip effect occurs due to a break in the azimuthal coherence of the unsteady flow. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Taitech Inc, Beavercreek, OH 45430 USA. RP Zaman, KBMQ (reprint author), NASA, Glenn Res Ctr, Lewis Field, Cleveland, OH 44135 USA. NR 35 TC 27 Z9 27 U1 2 U2 7 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 JUL 25 PY 2002 VL 463 BP 313 EP 343 DI 10.1017/S0022112002008819 PG 31 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 584PE UT WOS:000177475400012 ER PT J AU Huang, B Smith, WL Huang, HL Woolf, HM AF Huang, B Smith, WL Huang, HL Woolf, HM TI Comparison of linear forms of the radiative transfer equation with analytic Jacobians SO APPLIED OPTICS LA English DT Article ID ACCURATE TRANSMITTANCE MODEL; ABSORBING GAS; ATMOSPHERIC TRANSMITTANCE; COMPUTATIONALLY FAST; MIXING RATIOS; TEMPERATURE; RETRIEVAL; RADIANCE; SOUNDER AB Determining the Jacobians of the radiative transfer equation (RTE) is important to the qualities of the simultaneous retrieval of geophysical parameters from satellite radiance observations and the assimilation of radiance data into a numerical weather prediction system. Two linear forms of the RTE with analytic Jacobians are formulated. The first linear form has approximate analytic Jacobians, which involves some monochromatic approximation applied to a fast transmittance model. Unlike previous research, which lacks the transmittance Jacobian with respect to the atmospheric temperature profile, this form is complete in the sense that, the transmittance Jacobians with respect to atmospheric temperature and absorbing constituent profiles are both present. The second linear form has exact analytic Jacobians derived consistently from the same fast transmittance model without using any monochromatic approximation. By numerical comparison between the two linear forms for the NOAA-12 High-Resolution Infrared Sounder, we show significant errors in the linear form with approximate analytic Jacobians. The relative absolute linearization error from the linear form with approximate analytic Jacobians is shown to be 2-4 orders of magnitude larger than that from the linear form with exact analytic Jacobians, even for the case of a 0.1% perturbation of the U.S. Standard Atmosphere. The errors unnecessarily complicate the ill-posed retrieval problem of atmospheric remote sensing and can be avoided if the correct linear form of the RTE with exact analytic Jacobians is adopted. (C) 2002 Optical Society of America. C1 Univ Wisconsin, Ctr Space Sci & Engn, Madison, WI 53706 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Huang, B (reprint author), Univ Wisconsin, Ctr Space Sci & Engn, 1225 W Dayton St, Madison, WI 53706 USA. EM bormin@ssec.wise.edu NR 18 TC 35 Z9 35 U1 0 U2 8 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD JUL 20 PY 2002 VL 41 IS 21 BP 4209 EP 4219 DI 10.1364/AO.41.004209 PG 11 WC Optics SC Optics GA 575WU UT WOS:000176972100001 PM 12148748 ER PT J AU Logan, JE Halverson, PG Regehr, MW Spero, RE AF Logan, JE Halverson, PG Regehr, MW Spero, RE TI Automatic alignment of a displacement-measuring heterodyne interferometer SO APPLIED OPTICS LA English DT Article AB A technique to align automatically the beams of displacement-measuring interferometric gauges is described. The pointing of the launched beam is modulated in a circular pattern, and the resulting displacement signal is demodulated synchronously to determine the alignment error. This error signal is used in a control system that maintains the alignment for maximum path between a pair of fiducial hollow-cube corner retroreflectors, which minimizes sensitivity to alignment drift. The technique is tested on a developmental gauge of the type intended for the Space Interferometry Mission. The displacement signal for the gauge is generated in digital form; and the lock-in amplifier functions of modulation, demodulation, and filtering are all implemented digitally. (C) 2002 Optical Society of America. C1 Mission Res Corp, Torrance, CA 90503 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Logan, JE (reprint author), Mission Res Corp, Torrance, CA 90503 USA. EM spero@jpl.nasa.gov NR 9 TC 8 Z9 8 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 JUL 20 PY 2002 VL 41 IS 21 BP 4314 EP 4317 DI 10.1364/AO.41.004314 PG 4 WC Optics SC Optics GA 575WU UT WOS:000176972100011 PM 12148758 ER PT J AU Simpson, JP Colgan, SWJ Erickson, EF Hines, DC Schultz, ASB Trammell, SR AF Simpson, JP Colgan, SWJ Erickson, EF Hines, DC Schultz, ASB Trammell, SR TI Hubble Space Telescope NICMOS observations of the polarization of NGC 1068 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : individual (NGC 1068) galaxies : Seyfert; infrared : galaxies; polarization ID SEYFERT-2 GALAXY NGC-1068; NARROW-LINE REGION; IMAGING SPECTROPHOTOMETRY; IONIZED-GAS; SPIRAL STRUCTURE; ADAPTIVE OPTICS; INNER DISK; NUCLEUS; EMISSION; SPECTROPOLARIMETRY AB We have observed the polarized light at 2 mum in the center of NGC 1068 with NICMOS Camera 2 on the Hubble Space Telescope. The nucleus is dominated by a bright, unresolved source, polarized at a level of 6.0% +/- 1.2% with a position angle of 122degrees +/- 15degrees. There are two polarized lobes extending up to 8" northeast and southwest of the nucleus. The polarized flux in both lobes is quite clumpy, with the maximum polarization occurring in the southwest lobe at a level of 17% when smoothed to 0."23 resolution. The perpendiculars to the polarization vectors in these two lobes point back to the intense unresolved nuclear source to within one 0."076 Camera 2 pixel, thereby confirming that this is the illuminating source of the scattered light and therefore the probable active galactic nucleus central engine. Whereas the polarization of the nucleus is probably caused by dichroic absorption, the polarization in the lobes is almost certainly caused by scattering, with very little contribution from dichroic absorption. Features in the polarized lobes include a gap at a distance of about 1" from the nucleus toward the southwest lobe and a knot of emission about 5" northeast of the nucleus. Both features had been discussed by ground-based observers, but they are much better defined with the high spatial resolution of NICMOS. The northeast knot may be the side of a molecular cloud that is facing the nucleus, which may be preventing the expansion of the northeast radio lobe at the head of the radio synchrotron-radiation emitting jet. We also report the presence of two ghosts in the Camera 2 polarizers. These had not been detected previously ( Hines et al.) because they are relatively faint and require observations of a source with a large dynamic range. C1 NASA, Ames Res Ctr, Astrophys Branch, Moffett Field, CA 94035 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Univ New S Wales, Sch Phys, Sydney, NSW 2052, Australia. Univ N Carolina, Dept Phys, Charlotte, NC 28223 USA. RP Simpson, JP (reprint author), NASA, Ames Res Ctr, Astrophys Branch, MS 245-6, Moffett Field, CA 94035 USA. RI Colgan, Sean/M-4742-2014 NR 52 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 JUL 20 PY 2002 VL 574 IS 1 BP 95 EP 103 DI 10.1086/340946 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 575ZK UT WOS:000176978200010 ER PT J AU Michael, E Zhekov, S McCray, R Hwang, U Burrows, DN Park, S Garmire, GP Holt, SS Hasinger, G AF Michael, E Zhekov, S McCray, R Hwang, U Burrows, DN Park, S Garmire, GP Holt, SS Hasinger, G TI X-ray spectrum of supernova remnant 1987A SO ASTROPHYSICAL JOURNAL LA English DT Article DE shock waves; supernova remnants; supernovae : individual (SN 1987A); X-rays : ISM ID SPACE-TELESCOPE OBSERVATIONS; SN 1987A; CIRCUMSTELLAR RING; LINE EMISSION; RADIO REMNANT; SN-1987A; ABUNDANCES; SPECTROSCOPY; EMERGENCE; ELEMENTS AB We discuss the X-ray emission observed from supernova remnant 1987A with the Chandra X-Ray Observatory. We analyze a high-resolution spectrum obtained in 1999 October with the high-energy transmission grating (HETG). From this spectrum we measure the strengths and an average pro le of the observed X-ray lines. We also analyze a high signal-to-noise ratio CCD spectrum obtained in 2000 December. The good statistics (approximate to9250 counts) of this spectrum and the high spatial resolution provided by the telescope allow us to perform spectroscopic analyses of different regions of the remnant. We discuss the relevant shock physics that can explain the observed X-ray emission. The X-ray spectra are well fitted by plane-parallel shock models with postshock electron temperatures of approximate to2.6 keV and ionization ages of approximate to6 x 10(10) cm(-3) s. The combined X-ray line pro le has a FWHM of approximate to5000 km s(-1), indicating a blast-wave speed of approximate to3500 km s(-1). At this speed, plasma with a mean postshock temperature of approximate to17 keV is produced. This is direct evidence for incomplete electron-ion temperature equilibration behind the shock. Assuming this shock temperature, we constrain the amount of collisionless electron heating at the shock front at T-e0/T-s = 0.11(-0.01)(+0.02). We find that the plasma has low metallicity (abundances are approximate to0.1-0.4 solar) and is nitrogen enriched (N/O approximate to 0.8 by number), similar to abundances found for the equatorial ring. Analysis of the spectra from different regions of the remnant reveals slight differences in the parameters of the emitting plasma. The plasma is cooler near the optical spot 1 (at position angle approximate to30degrees) and in the eastern half of the remnant, where the bright optical spots are found, than in the western half, consistent with the presence of slower (approximate to500 km s(-1)) shocks entering denser ring material. There is an overall flux asymmetry between the two halves, with the eastern half being 15%-50% brighter (depending on how the center of the remnant is defined). However, our spectroscopic analysis shows that less than 5% of the overall X-ray emission could come from a slow shock component. Therefore the flux asymmetry cannot fully be due to X-rays produced by the blast wave entering the ring, but rather indicates an asymmetry in the global interaction with the circumstellar material interior to the ring. C1 Univ Colorado, JILA, Boulder, CO 80309 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA. FW Olin Coll Engn, Needham, MA 02492 USA. Max Planck Inst Extraterr Phys, D-85748 Garching, Germany. RP Michael, E (reprint author), Univ Colorado, JILA, Campus Box 440, Boulder, CO 80309 USA. NR 43 TC 55 Z9 55 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 20 PY 2002 VL 574 IS 1 BP 166 EP 178 DI 10.1086/340591 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 575ZK UT WOS:000176978200016 ER PT J AU Feigelson, ED Broos, P Gaffney, JA Garmire, G Hillenbrand, LA Pravdo, SH Townsley, L Tsuboi, Y AF Feigelson, ED Broos, P Gaffney, JA Garmire, G Hillenbrand, LA Pravdo, SH Townsley, L Tsuboi, Y TI X-ray emitting young stars in the Orion Nebula SO ASTROPHYSICAL JOURNAL LA English DT Review DE open clusters and associations : individual (Orion Nebula Cluster); stars : activity; stars : early-type; stars : low-mass, brown dwarfs; stars : pre-main-sequence; X-rays : stars ID MAIN-SEQUENCE STARS; T-TAURI STARS; ROSAT PSPC OBSERVATIONS; LOW-MASS STARS; BROWN DWARFS; EINSTEIN OBSERVATIONS; STELLAR POPULATION; CIRCUMSTELLAR DISK; SOURCE VARIABILITY; TRAPEZIUM-CLUSTER AB The Orion Nebula Cluster and the molecular cloud in its vicinity have been observed with the ACIS-I detector on board the Chandra X-ray Observatory with 23 hr exposure in two observations. We detect 1075 X-ray sources, most with subarcsecond positional accuracy. Ninety-one percent of the sources are spatially associated with known stellar members of the cluster, and an additional 7% are newly identified deeply embedded cloud members. This provides the largest X-ray study of a premain-sequence stellar population and covers the initial mass function from brown dwarfs up to a 45 M. O star. Source luminosities span 5 orders of magnitude from log L-X similar or equal to28.0 to 33.3 ergs s(-1) in the 0.5-8 keV band, plasma energies range from 0.2 to >10 keV, and absorption ranges from log N-H < 20.0 to similar to 23.5 cm(-2). Comprehensive tables providing X-ray and stellar characteristics are provided electronically. We examine here the X-ray properties of Orion young stars as a function of mass; other studies of astrophysical interest will appear in companion papers. Results include: ( a) the discovery of rapid variability in the 09.5 31 M. star theta(2)A Ori, and several early B stars, inconsistent with the standard model of X-ray production in small shocks distributed throughout the radiatively accelerated wind; (b) support for the hypothesis that intermediate-mass mid-B through A type stars do not themselves produce significant X-ray emission; (c) confirmation that low-mass G through M type T Tauri stars exhibit powerful flaring but typically at luminosities considerably below the saturation level; (d) confirmation that the presence or absence of a circumstellar disk has no discernable effect on X-ray emission; (e) evidence that T Tauri plasma temperatures are often very high with T >= 100 MK, even when luminosities are modest and flaring is not evident; and (f) detection of the largest sample of pre-main-sequence very low-mass objects showing flaring levels similar to those seen in more massive T Tauri stars and a decline in magnetic activity as they evolve into L and T type brown dwarfs. C1 Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA. CALTECH, Dept Astron, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA. NR 115 TC 227 Z9 227 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD JUL 20 PY 2002 VL 574 IS 1 BP 258 EP 292 DI 10.1086/340936 PN 1 PG 35 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 575ZK UT WOS:000176978200023 ER PT J AU Swartz, DA Ghosh, KK Suleimanov, V Tennant, AF Wu, KW AF Swartz, DA Ghosh, KK Suleimanov, V Tennant, AF Wu, KW TI Chandra discovery of luminous supersoft X-ray sources in M81 SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : symbiotic; stars : atmospheres; stars : evolution; white dwarfs; X-rays : stars ID ACCRETING WHITE-DWARFS; PHOTOIONIZATION CROSS-SECTIONS; EXTRAGALACTIC DISTANCE SCALE; NEARBY SPIRAL GALAXIES; HIGH-RESOLUTION CAMERA; ALL-SKY SURVEY; BEPPOSAX OBSERVATION; PLANETARY-NEBULAE; DEGENERATE DWARFS; MAGELLANIC CLOUD AB A Chandra ACIS-S imaging observation of the nearby galaxy M81 (NGC 3031) reveals nine luminous soft X-ray sources. The local environments, X-ray spectral properties, and X-ray light curves of the sources are presented and discussed in the context of prevailing physical models for supersoft sources. It is shown that the sample falls within expectations based on population synthesis models taken from the literature, although the high observed luminosities (L(obs) similar to 2 x 10(36)-3 x 10(38) ergs s(-1) in the 0.2-2.0 keV band) and equivalent blackbody temperatures (T(eff) similar to 40-80 eV) place the brightest detected M81 objects at the high-luminosity end of the class of supersoft sources defined by previous ROSAT and Einstein studies of nearby galaxies. This is interpreted as a natural consequence of the higher sensitivity of Chandra to hotter and more luminous systems. Most of the sources can be explained as canonical supersoft sources: accreting white dwarfs powered by steady surface nuclear burning with X-ray spectra well fitted by hot white dwarf local thermodynamic equilibrium atmosphere models. An exceptionally bright source is scrutinized in greater detail since its estimated bolometric luminosity, L(bol) similar to 1.5 x 10(39) ergs s(-1), greatly exceeds theoretical estimates for supersoft sources. This source may be beyond the stability limit and undergoing a phase of mass outflow under extreme conditions. Alternatively, a model in which the observed X-ray spectrum arises from an accretion disk around a black hole of mass similar to1200/(cos i)(1/2) M. (viewed at an inclination angle i) cannot be excluded. C1 NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, Huntsville, AL 35812 USA. Kazan VI Lenin State Univ, Kazan 420008, Russia. NASA, George C Marshall Space Flight Ctr, Dept Space Sci, Huntsville, AL 35812 USA. UCL, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England. Univ Sydney, Sch Phys, Sydney, NSW 2006, Australia. RP Swartz, DA (reprint author), NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, SD50, Huntsville, AL 35812 USA. NR 76 TC 55 Z9 55 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 JUL 20 PY 2002 VL 574 IS 1 BP 382 EP 397 DI 10.1086/340926 PN 1 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 575ZK UT WOS:000176978200032 ER PT J AU Moon, YJ Choe, GS Park, YD Wang, HM Gallagher, PT Chae, J Yun, HS Goode, PR AF Moon, YJ Choe, GS Park, YD Wang, HM Gallagher, PT Chae, J Yun, HS Goode, PR TI Statistical evidence for sympathetic flares SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : corona; Sun : flares; Sun : X-rays, gamma rays ID LOOPS AB Sympathetic flares are a pair of flares that occur almost simultaneously in different active regions, not by chance, but because of some physical connection. In this paper statistical evidence for the existence of sympathetic flares is presented. From GOES X-ray are data, we have collected 48 pairs of near simultaneous flares whose positional information and Yohkoh soft X-ray telescope images are available. To select the active regions that probably have sympathetic flares, we have estimated the ratio R of actual flaring overlap time to random-coincidence overlap time for 38 active region pairs. We have then compared the waiting-time distributions for the two different groups of active region pairs (R > 1 and R < 1) with corresponding nonstationary Poisson distributions. As a result, we find a remarkable overabundance of short waiting times for the group with R > 1. This is the first time such strong statistical evidence has been found for the existence of sympathetic flares. To examine the role of interconnecting coronal loops, we have also conducted the same analysis for two subgroups of the R > 1 group: one with interconnecting X-ray loops and the other without. We do not find any statistical evidence that the subgroup with interconnecting coronal loops is more likely to produce sympathetic flares than the subgroup without. For the subgroup with loops, we find that sympathetic flares favor active region pairs with transequatorial loops. C1 New Jersey Inst Technol, Big Bear Solar Observ, Yooseong Ku, Big Bear City, CA 92314 USA. Korea Astron Observ, Yooseong Ku, Taejon 305348, South Korea. Princeton Univ, Plasma Phys Lab, Princeton, NJ 08543 USA. NASA, Goddard Space Flight Ctr, Emergent Technol Serv Inc, Greenbelt, MD 20771 USA. Chungnam Natl Univ, Dept Astron & Space Sci, Yusong Ku, Taejon 305764, South Korea. Seoul Natl Univ, SEES, Astron Program, Seoul 151742, South Korea. RP Moon, YJ (reprint author), New Jersey Inst Technol, Big Bear Solar Observ, Yooseong Ku, 40386 N Shore Lane, Big Bear City, CA 92314 USA. RI Moon, Yong-Jae/E-1711-2013; Choe, Gwangson/E-2366-2013; Gallagher, Peter/C-7717-2011 OI Gallagher, Peter/0000-0001-9745-0400 NR 14 TC 46 Z9 46 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 20 PY 2002 VL 574 IS 1 BP 434 EP 439 DI 10.1086/340945 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 575ZK UT WOS:000176978200037 ER PT J AU Ofman, L Thompson, BJ AF Ofman, L Thompson, BJ TI Interaction of EIT waves with coronal active regions SO ASTROPHYSICAL JOURNAL LA English DT Article DE MHD; Sun : corona; Sun : magnetic fields; waves ID SOLAR CORONA; LOOP OSCILLATIONS; TRANSITION REGION; MORETON WAVES; EXCITATION; SIMULATION; EVOLUTION; EXPLORER; TRACE AB Large-scale coronal waves associated with flares were first observed by the Solar and Heliospheric Observatory (SOHO) Extreme ultraviolet Imaging Telescope (EIT). We present the first three-dimensional MHD modeling of the interaction of the EIT waves with active regions and the possibility of destabilization of an active region by these waves. The active region is modeled by an initially force-free, bipolar magnetic configuration with gravitationally stratified density. We include finite thermal pressure and resistive dissipation in our model. The EIT wave is launched at the boundary of the region, as a short time velocity pulse that travels with the local fast magnetosonic speed toward the active region. We find that the EIT wave undergoes strong reflection and refraction, in agreement with observations, and induces transient currents in the active region. The resulting Lorentz force leads to the dynamic distortion of the magnetic field and to the generation of secondary waves. The resulting magnetic compression of the plasma induces flows, which are particularly strong in the current-carrying active region. We investigate the effect of the magnetic field configuration and find that the current-carrying active region is destabilized by the impact of the wave. Analysis of the three-dimensional interaction between EIT waves and active regions can serve as a diagnostic of the active region coronal magnetic structure and stability. C1 NASA, Goddard Space Flight Ctr, Catholic Univ Amer, Greenbelt, MD 20771 USA. RP Ofman, L (reprint author), NASA, Goddard Space Flight Ctr, Catholic Univ Amer, Code 682, Greenbelt, MD 20771 USA. RI Thompson, Barbara/C-9429-2012 NR 35 TC 117 Z9 118 U1 0 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 20 PY 2002 VL 574 IS 1 BP 440 EP 452 DI 10.1086/340924 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 575ZK UT WOS:000176978200038 ER PT J AU Brosius, JW Landi, E Cook, JW Newmark, JS Gopalswamy, N Lara, A AF Brosius, JW Landi, E Cook, JW Newmark, JS Gopalswamy, N Lara, A TI Measurements of three-dimensional coronal magnetic fields from coordinated extreme-ultraviolet and radio observations of a solar active region sunspot SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : activity; Sun : corona; Sun : magnetic fields; Sun : radio radiation; Sun : UV radiation; sunspots ID STRUCTURES OBSERVING CAMPAIGN; HIGH-SPATIAL-RESOLUTION; OPTICALLY THIN PLASMAS; X-RAY OBSERVATIONS; EMISSION-LINES; ATOMIC DATABASE; MICROWAVE; TEMPERATURE; SUN; SPECTRUM AB We observed NOAA Active Region 8108 around 1940 UT on 1997 November 18 with the Very Large Array and with three instruments aboard the NASA/ESA Solar and Heliospheric Observatory satellite, including the Coronal Diagnostic Spectrometer, the EUV Imaging Telescope, and the Michelson Doppler Imager. We used the right-hand and left-hand circularly polarized components of the radio observing frequencies, along with the coordinated EUV observations, to derive the three-dimensional coronal magnetic field above the regions sunspot and its immediate surroundings. This was done by placing the largest possible harmonic (which corresponds to the smallest possible magnetic field strength) for each component of each radio frequency into appropriate atmospheric temperature intervals such that the calculated radio brightness temperatures at each spatial location match the corresponding observed values. The temperature dependence of the derived coronal magnetic field, B(x, y, T), is insensitive to uncertainties on the observed parameters and yields field strengths in excess of 580 G at 2 x 10(6) K and in excess of 1500 G at 1 x 10(6) K. The height dependence of the derived coronal magnetic field, B(x, y, T), varies significantly with our choice of magnetic scale height L-B. Based on L-B = 3.8 x 10(9) cm derived from the relative displacements of the observed radio centroids, we find magnetic field strengths in excess of 1500 G at heights of 15,000 km and as great as 1000 G at 25,000 km. By observing a given target region on several successive days, we would obtain observations at a variety of projection angles, thus enabling a better determination of L-B and, ultimately, B(x, y, h). We compare coronal magnetic fields derived from our method with those derived from a potential extrapolation and find that the magnitudes of the potential field strengths are factors of 2 or more smaller than those derived from our method. This indicates that the sunspot field is not potential and that currents must be present in the corona. Alfven speeds between 25,000 and 57,000 km s(-1) are derived for the 1 x 10(6) K plasma at the centroids of the radio observing frequencies. Filling factors between 0.003 and 0.1 are derived for the 1 x 10(6) K plasma at the centroids of the radio observing frequencies. C1 NASA, Goddard Space Flight Ctr, Catholic Univ, Greenbelt, MD 20771 USA. USN, Res Lab, ARTEP Inc, Washington, DC 20375 USA. USN, Res Lab, Washington, DC 20375 USA. Univ Nacl Autonoma Mexico, Inst Geofis, Mexico City 04510, DF, Mexico. RP NASA, Goddard Space Flight Ctr, Catholic Univ, Code 682, Greenbelt, MD 20771 USA. RI Landi, Enrico/H-4493-2011; Gopalswamy, Nat/D-3659-2012; OI Lara, Alejandro/0000-0001-6336-5291; Gopalswamy, Nat/0000-0001-5894-9954 NR 47 TC 26 Z9 26 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD JUL 20 PY 2002 VL 574 IS 1 BP 453 EP 466 DI 10.1086/340923 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 575ZK UT WOS:000176978200039 ER PT J AU Doron, R Doschek, GA Feldman, U Bhatia, AK Bar-Shalom, A AF Doron, R Doschek, GA Feldman, U Bhatia, AK Bar-Shalom, A TI The effect of high-lying levels on atomic models relevant to spectroscopic analyses of solar extreme-ultraviolet spectra SO ASTROPHYSICAL JOURNAL LA English DT Article DE atomic data; atomic processes; Sun : UV radiation; techniques : spectroscopic ID TRANSITION REGION; CROSS-SECTIONS; AL-III; SI-IV; LINES; IONS; TEMPERATURE; EMISSION; PLASMAS; ATMOSPHERE AB In this work we investigate the effect of including high-lying configurations in the collisional-radiative models used to calculate spectral line intensities recorded by the Solar Ultraviolet Measurement of Emitted Radiation (SUMER) spectrometer on board the SOHO satellite. Many of the emission lines observed by SUMER are attributed to transitions within the L and M electronic shells of ions isoelectronic to sequences from Li I to Na I By using atomic data that are mostly generated by the Hebrew University Lawrence Livermore Atomic Code (HULLAC), we incorporate in the atomic models configurations from higher shells and systematically study their effect on the calculated line intensities in selected ions. The high-lying configurations alter the line intensities through radiative cascades and configuration interaction effects. We find that cascades can significantly enhance the line intensities of the considered ions by up to 60% at temperatures of the ion maximum fractional abundance. The enhancement due to cascades increases with increasing temperature and charge state. The configuration mixing effects can either enhance or reduce the line intensities. Generally, the mixing effect becomes less important for higher charge states. C1 George Mason Univ, Inst Computat Sci & Informat, Fairfax, VA 22030 USA. USN, Res Lab, EO Hulburt Ctr Space Res, Washington, DC 20375 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. ARTEP Inc, Columbia, MD 21045 USA. RP Doron, R (reprint author), USN, Res Lab, EO Hulburt Ctr Space Res, Code 7670D,4555 Overlook Ave SW, Washington, DC 20375 USA. RI Doron, Ramy/I-2064-2013 NR 22 TC 9 Z9 9 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 20 PY 2002 VL 574 IS 1 BP 504 EP 512 DI 10.1086/340839 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 575ZK UT WOS:000176978200043 ER PT J AU Ibrahim, AI Safi-Harb, S Swank, JH Parke, W Zane, S Turolla, R AF Ibrahim, AI Safi-Harb, S Swank, JH Parke, W Zane, S Turolla, R TI Discovery of cyclotron resonance features in the Soft Gamma Repeater 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 MAGNETIZED NEUTRON-STARS; HIGH-ENERGY TRANSIENT; X-RAY-SPECTRUM; SGR 1900+14; POPULATION SYNTHESIS; ABSORPTION FEATURE; PULSARS; FIELD; BURST; NURTURE AB We report evidence of cyclotron resonance features from the Soft Gamma Repeater SGR 1806-20 in outburst, detected with the Rossi X-Ray Timing Explorer in the spectrum of a long, complex precursor that preceded a strong burst. The features consist of a narrow 5.0 keV absorption line with modulation near its second and third harmonics (at 11.2 and 17.5 keV, respectively). The line features are transient and are detected in the harder part of the precursor. The 5.0 keV feature is strong, with an equivalent width of similar to500 eV and a narrow width of less than 0.4 keV. Interpreting the features as electron-cyclotron lines in the context of accretion models leads to a large mass-to-radius ratio (M/R > 0.3 M. km(-1)) that is inconsistent with neutron stars or that requires a low (5-7) x 10(11) G magnetic field that is unlikely for SGRs. The line widths are also narrow compared with those of electron-cyclotron resonances observed so far in X-ray pulsars. In the magnetar picture, the features are plausibly explained as being ion-cyclotron resonances in an ultrastrong magnetic field that have recently been predicted from magnetar candidates. In this view, the 5.0 keV feature is consistent with a proton-cyclotron fundamental whose energy and width are close to model predictions. The line energy would correspond to a surface magnetic field of 1.0 x 10(15) G for SGR 1806-20, in good agreement with that inferred from the spin-down measure in the source. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. George Washington Univ, Dept Phys, Washington, DC 20052 USA. Univ Manitoba, Dept Phys & Astron, Winnipeg, MB R3T 2N2, Canada. Univ Space Res Assoc, Columbia, MD USA. UCL, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England. Univ Padua, Dept Phys, I-35131 Padua, Italy. RP NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. EM alaa@milkyway.gsfc.nasa.gov RI Ibrahim, Alaa/A-6250-2008; Swank, Jean/F-2693-2012 OI Ibrahim, Alaa/0000-0002-8791-7270; NR 36 TC 69 Z9 69 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 JUL 20 PY 2002 VL 574 IS 1 BP L51 EP L55 DI 10.1086/342366 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 575ZL UT WOS:000176978300012 ER PT J AU Wren, DN Bertsch, DL Ritz, S AF Wren, DN Bertsch, DL Ritz, S TI Evidence for postquiescent, high-energy emission from gamma-ray burst 990104 SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts; gamma rays : observations AB It is well known that high-energy emission (MeV-GeV) has been observed in a number of gamma-ray bursts, and temporally extended emission from lower energy gamma rays through radio wavelengths is well established. An important observed characteristic of some bursts at low energy is quiescence: an initial emission followed by a quiet period before a second (postquiescent) emission. Evidence for significant high-energy, postquiescent emission has been lacking. Here we present evidence for high-energy emission, coincident with lower energy emission, from the postquiescent emission episode of the very bright and long burst, GRB 990104. We show light curves and spectra that confirm emission above 50 MeV, approximately 152 s after the BATSE trigger and initial emission episode. Between the initial emission episode and the main peak, seen at both low and high energy, there was a quiescent period of similar to100 s during which the burst was relatively quiet. This burst was found as part of an ongoing search for high-energy emission in gamma-ray bursts using the EGRET fixed interval (32 s) accumulation spectra, which provide sensitivity to later, high-energy emission that is otherwise missed by the standard EGRET BATSE-triggered burst spectra. C1 Univ Maryland, Dept Phys, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Wren, DN (reprint author), Univ Maryland, Dept Phys, Greenbelt, MD 20771 USA. NR 16 TC 4 Z9 5 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 20 PY 2002 VL 574 IS 1 BP L47 EP L50 DI 10.1086/342367 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 575ZL UT WOS:000176978300011 ER PT J AU Acker, JG Brown, CW Hine, AC Armstrong, E Kuring, N AF Acker, JG Brown, CW Hine, AC Armstrong, E Kuring, N TI Satellite remote sensing observations and aerial photography of storm-induced neritic carbonate transport from shallow carbonate platforms SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID OCEAN; SEDIMENTATION; ACCUMULATION; BANK AB Shallow carbonate platforms are a significant source of biogenic calcium carbonate (CaCO3) in the marine environment, second in production only to coral reefs. The mechanisms by which platform-derived neritic carbonates are transported to the pelagic water column and deep benthos are significant to the geological history of shallow carbonate platforms and the role of neritic carbonates in the marine carbon cycle. Aerial photography and satellite remote sensing observations of the Bahamas Banks and Bermuda indicate that major sediment transport events are caused by strong surface winds associated with storm systems. While this mechanism is not unexpected, these observations provide an initial assessment of the potential ability of remote sensing to detect these events and quantify the offshore mass transport of neritic carbonate. Strategies for observational monitoring of selected platform environments are described. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NOAA, NESDIS, Camp Springs, MD 20746 USA. Univ S Florida, Dept Marine Sci, St Petersburg, FL 33701 USA. CALTECH, Jet Prop Lab, Phys Oceanog DAAC, Pasadena, CA 91109 USA. RP Acker, JG (reprint author), NASA, Goddard Space Flight Ctr, Code 902, Greenbelt, MD 20771 USA. RI Brown, Christopher/B-8213-2008 OI Brown, Christopher/0000-0002-9905-6391 NR 16 TC 13 Z9 13 U1 0 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 JUL 20 PY 2002 VL 23 IS 14 BP 2853 EP 2868 DI 10.1080/01431160110106122 PG 16 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 575LY UT WOS:000176948800007 ER PT J AU Thompson, CM Hergenrother, PM AF Thompson, CM Hergenrother, PM TI Aryl ethynyl terminated imide oligomers and their cured polymers SO MACROMOLECULES LA English DT Article ID END; ANHYDRIDES; COMPOSITES AB As part of a program to develop resins for high-performance/high-temperature aerospace structural applications, preliminary neat resin properties of naphthylethynyl terminated imide oligomers were determined and compared with the corresponding phenylethynyl terminated imide oligomers. Prior to oligomer work, four naphthylethynyl and phenylethynyl phthalimide and four naphthylethynyl and phenylethynyl naphthalimide model compounds were prepared and their thermal properties compared. The naphthylethynyl end-caps in N-phenyl- or N-naphthylphthalimide model compounds reacted at a lower temperature than the phenylethynyl end-cap in the same compounds, as previously reported. In contrast to these results, replacement of the phthalimide groups with naphthalimide groups showed that the phenylethynyl end-cap reacted at a lower temperature than the naphthylethynyl end-cap. Four aryl ethynyl terminated imide oligomers having the same imide backbone and molecular weight but different terminal units were prepared and the properties of the cured polymers compared. Phenylethynyl end-capped or naphthylethynyl end-capped oligomers, cured at 340 or 371 degreesC, exhibited similar tensile properties in thin films. The chemistry and properties of these materials are presented. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Hergenrother, PM (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 25 TC 24 Z9 24 U1 3 U2 17 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD JUL 16 PY 2002 VL 35 IS 15 BP 5835 EP 5839 AR UNSP MA0205358 DI 10.1021/ma0205358 PG 5 WC Polymer Science SC Polymer Science GA 573DT UT WOS:000176814600020 ER PT J AU Kwok, R Comiso, JC AF Kwok, R Comiso, JC TI Spatial patterns of variability in antarctic surface temperature: Connections to the Southern Hemisphere Annular Mode and the Southern Oscillation SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID EXTRATROPICAL CIRCULATION; PENINSULA; TRENDS AB [1] The 17-year (1982-1998) trend in surface temperature shows a general cooling over the Antarctic continent, warming of the sea ice zone, with moderate changes over the oceans. Warming of the peripheral seas is associated with negative trends in the regional sea ice extent. Effects of the Southern Hemisphere Annular Mode (SAM) and the extrapolar Southern Oscillation (SO) on surface temperature are quantified through regression analysis. Positive polarities of the SAM are associated with cold anomalies over most of Antarctica, with the most notable exception of the Antarctic Peninsula. Positive temperature anomalies and ice edge retreat in the Pacific sector are associated with El-Nino episodes. Over the past two decades, the drift towards high polarity in the SAM and negative polarity in the SO indices couple to produce a spatial pattern with warmer temperatures in the Antarctic Peninsula and peripheral seas, and cooler temperatures over much of East Antarctica. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Kwok, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Kwok, Ron/A-9762-2008 OI Kwok, Ron/0000-0003-4051-5896 NR 13 TC 110 Z9 112 U1 1 U2 18 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUL 15 PY 2002 VL 29 IS 14 AR 1705 DI 10.1029/2002GL015415 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 610MV UT WOS:000178964600002 ER PT J AU Liu, JP Yuan, XJ Rind, D Martinson, DG AF Liu, JP Yuan, XJ Rind, D Martinson, DG TI Mechanism study of the ENSO and southern high latitude climate teleconnections SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ANTARCTIC CIRCUMPOLAR WAVE; SEA-ICE EXTENT; TEMPERATURE; VARIABILITY; OSCILLATION; WINTER; OCEAN AB [1] Evidence of El Nino-Southern Oscillation (ENSO) teleconnections in the southern high latitude climate has been identified, although the mechanisms that might lead to such far-reaching teleconnections remain unresolved. Here we propose one such mechanism-the regional mean meridional atmospheric circulation (the regional Ferrel Cell)-responsible for the covariability of the ENSO and Antarctic Dipole (ADP; a predominant interannually-varying signal in the southern high latitudes). It is found that the altered storm tracks associated with the ENSO variability influence the regional Ferrel Cell indirectly by changing the meridional eddy heat flux divergence and convergence, and shifting the latent heat release zone. The changes of the regional Ferrel Cell then influence the southern high latitude climate by modulating the mean meridional heat flux. C1 NASA, Goddard Space Flight Ctr, Inst Space Studies, New York, NY 10025 USA. Columbia Univ, Lamont Doherty Earth Observ, New York, NY 10027 USA. Columbia Univ, Dept Earth & Environm Sci, New York, NY 10027 USA. RP Liu, JP (reprint author), NASA, Goddard Space Flight Ctr, Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. RI LIU, JIPING/N-6696-2016 NR 23 TC 40 Z9 44 U1 0 U2 8 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUL 15 PY 2002 VL 29 IS 14 AR 1679 DI 10.1029/2002GL015143 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 610MV UT WOS:000178964600026 ER PT J AU Reichardt, J Reichardt, S Behrendt, A McGee, TJ AF Reichardt, J Reichardt, S Behrendt, A McGee, TJ TI Correlations among the optical properties of cirrus-cloud particles: Implications for spaceborne remote sensing SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID LIDAR DEPOLARIZATION; RADIATIVE PROPERTIES; RAMAN LIDAR; CLIMATE; EXTINCTION; FACILITY; PHASE; OZONE AB [1] Lidar measurements of Arctic (67.9degreesN) cirrus clouds reveal a strong positive correlation between particle depolarization ratio and extinction-to-backscatter (lidar) ratio for ambient cloud temperatures above similar to-45degreesC, and an anti-correlation for colder temperatures. Similar correlations are evident in a 2-year midlatitude (53.5degreesN) cirrus data set. These data suggest that robust relationships may exist between these particle optical properties that will facilitate the retrieval of cirrus extinction profiles from polarization-sensitive (spaceborne) elastic-backscatter lidars. C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Atmospher Chem & Dynam Branch, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21228 USA. Kyoto Univ, Radio Sci Ctr Space & Atmosphere, Kyoto 6110011, Japan. RP Reichardt, J (reprint author), NASA, Goddard Space Flight Ctr, Atmospheres Lab, Atmospher Chem & Dynam Branch, Greenbelt, MD 20771 USA. RI McGee, Thomas/G-4951-2013; OI Behrendt, Andreas/0000-0003-2719-4354 NR 17 TC 17 Z9 17 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 JUL 15 PY 2002 VL 29 IS 14 AR 1668 DI 10.1029/2002GL014836 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 610MV UT WOS:000178964600037 ER PT J AU Wilson, RJ Banfield, D Conrath, BJ Smith, MD AF Wilson, RJ Banfield, D Conrath, BJ Smith, MD TI Traveling waves in the Northern Hemisphere of Mars SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID GENERAL-CIRCULATION MODEL; MARTIAN ATMOSPHERE; INSTABILITY; DYNAMICS; EDDIES AB [1] Analysis of temperature retrievals from Mars Global Surveyor Thermal Emission Spectrometer data has revealed the presence of regular, eastward propagating waves in the Northern Hemisphere. A large amplitude, zonal wave 1 with a long (similar to20 sol) period is particularly prominent during early winter (L-s = 220-270degrees). After L-s = 270degrees, a weaker and more rapidly propagating (6.5 sol period) zonal wave 1 is dominant. These waves have a deep vertical structure (>40 km) correlated with the axis of the winter hemisphere westerly jet. Simulations with a Mars general circulation model suggest that the fast wave is associated with baroclinic instability due to the strong meridional temperature gradient at the surface and is consistent with surface pressure oscillations seen in Viking Lander data. By contrast, the slow wave has the appearance of a large-amplitude Rossby wave that is coupled with an inertially unstable region in the subtropics. C1 NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Wilson, RJ (reprint author), NOAA, Geophys Fluid Dynam Lab, POB 308, Princeton, NJ 08542 USA. RI Smith, Michael/C-8875-2012; OI Banfield, Don/0000-0003-2664-0164 NR 20 TC 43 Z9 43 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 JUL 15 PY 2002 VL 29 IS 14 AR 1684 DI 10.1029/2002GL014866 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 610MV UT WOS:000178964600022 ER PT J AU Liu, L Mishchenkoa, MI Menon, S Macke, A Lacis, AA AF Liu, L Mishchenkoa, MI Menon, S Macke, A Lacis, AA TI The effect of black carbon on scattering and absorption of solar radiation by cloud droplets SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article DE black carbon; cloud water droplets; internal and external mixing; single-scattering co-albedo; asymmetry parameter ID LOWER STRATOSPHERE; OPTICAL-PROPERTIES; UPPER TROPOSPHERE; GRAPHITIC CARBON; LIGHT-SCATTERING; PARTICLES; AEROSOLS; ATMOSPHERE; INCLUSIONS; SPHERES AB Scattering and absorption characteristics of water cloud droplets containing black carbon (BC) inclusions are calculated at a visible wavelength of 0.55 mum by a combination of ray-tracing and Monte Carlo techniques. In addition, Lorenz-Mie calculations are performed assuming that the same amount of BC particles are mixed with water droplets externally. The results show that it is unlikely under normal conditions that BC aerosols can modify scattering and absorption properties of cloud droplets in any significant way except for geographical locations very close to major sources of BC. The differences in the single-scattering co-albedo and asymmetry parameter between BC-fraction-equivalent internal and external mixtures are negligibly small for normal black carbon loadings, which makes possible the use of the much simpler external mixing model in radiative transfer modeling irrespective of the actual form of mixing. For a fixed amount of BC internally mixed with cloud droplets, the absorption is maximal when the effective radius of the BC inclusions is about 0.05-0.06 mum. Published by Elsevier Science Ltd. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Columbia Univ, Dept Earth & Environm Sci, New York, NY 10025 USA. Univ Kiel, Inst Oceanog, D-24105 Kiel, Germany. RP Mishchenkoa, MI (reprint author), NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. RI Lacis, Andrew/D-4658-2012 NR 34 TC 21 Z9 25 U1 1 U2 7 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD JUL 15 PY 2002 VL 74 IS 2 BP 195 EP 204 AR PII S0022-4073(01)00232-1 DI 10.1016/S0022-4073(01)00232-1 PG 10 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 549FM UT WOS:000175433900005 ER PT J AU Rinsland, CP Zander, R Mahieu, E Chiou, LS Goldman, A Jones, NB AF Rinsland, CP Zander, R Mahieu, E Chiou, LS Goldman, A Jones, NB TI Stratospheric HF column abundances above Kitt Peak (31.9 degrees N latitude): trends from 1977 to 2001 and correlations with stratospheric HCl columns SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article DE hydrogen fluoride; remote sensing; stratosphere; atmospheric chemistry; infrared spectroscopy ID INFRARED SPECTROSCOPIC MEASUREMENTS; HALOGEN OCCULTATION EXPERIMENT; FREE TROPOSPHERIC CO; HYDROGEN-FLUORIDE; JUNGFRAUJOCH STATION; FUNDAMENTAL BANDS; CHLORINE; INCREASE; C2H6; OZONE AB Time series of stratospheric hydrogen fluoride (HF) column abundances have been derived from infrared solar absorption spectra recorded for 195 days between May 1977 and June 2001 at a spectral resolution of typically 0.01 cm(-1). The measurements were made at the US National Solar Observatory facility on Kitt Peak, Arizona, USA (31.9degreesN, 111.6degreesW, 2.09 km altitude) and have been analyzed with the SFIT2 algorithm, which is based on a semi-empirical application of the optimal estimation method. The measurements show a continuous buildup of the stratospheric HF column over the 24-yr period superimposed on short-term variations and a seasonal cycle with spring maxima and autumn minima. The measured stratospheric HF columns increased by a factor of 4.7, from 2.03 x 10(14) molecule cm(-2) in May 1977 to 9.49 x 10(14) molecule cm(-2) in June 2001. A best fit with a model that assumes an exponential increase in the stratospheric HF column with time superimposed on a sinusoidal seasonal cycle yields an average rate of stratospheric HF column increase of (4.30 +/- 0.15% yr(-1)), 1 sigma. The rate of increase is nearly a factor of two less than that derived previously from 1977 to 1990 Kitt Peak total columns, which indicates a significant slowdown in the increase rate during the 1990s, consistent with the trends from recent near-global lower mesospheric satellite remote and surface in situ measurements. Day-to-day stratospheric HIT columns are highly correlated with the same day stratospheric HCl columns as a result of common transport of lower and higher latitude air to above the station. Extrapolation of the linear relation between the two sets of stratospheric columns indicates a background HCl column of 1 x 10(15) molecule cm(-2) for zero HF, consistent with a previous estimate from 1977 to 1990 HF and HCl Kitt Peak total column measurements and a 1973 HCl measurement above the station. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Univ Liege, Inst Astrophys & Geophys, B-4000 Liege, Belgium. Wyle Labs, Hampton, VA 23666 USA. Univ Denver, Dept Phys, Denver, CO 80208 USA. Natl Inst Water & Atmospher Res, Lauder, New Zealand. RP Rinsland, CP (reprint author), NASA, Langley Res Ctr, Mail Stop 401A,21 Langley Blvd, Hampton, VA 23681 USA. RI Jones, Nicholas/G-5575-2011 OI Jones, Nicholas/0000-0002-0111-2368 NR 37 TC 13 Z9 13 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD JUL 15 PY 2002 VL 74 IS 2 BP 205 EP 216 AR PII S0022-4073(01)00233-3 DI 10.1016/S0022-4073(01)00233-3 PG 12 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 549FM UT WOS:000175433900006 ER PT J AU Petkov, MP Lynn, KG van Veen, A AF Petkov, MP Lynn, KG van Veen, A TI Experimental and theoretical aspects of electric-field-assisted positron kinetics in metal-oxide-silicon systems SO PHYSICAL REVIEW B LA English DT Article ID SI/SIO2 INTERFACE; MOBILITY; SURFACES; SIO2-SI; MODEL; SI AB We use positron annihilation spectroscopy to study positron kinetics in electrically biased metal-oxide-silicon (MOS) system and trapping at the SiO2/Si interface. Experiments carried out on samples with an extra thick (1 mum) oxide layer reveal the electric-field-assisted positron transport in the oxide, and bring supportive evidence for the two-defect-state trapping model of the SiO2/Si interface. The time-dependent drift-diffusion equation was solved for oxide-implanted positrons in order to obtain the fractions of positrons annihilating in the oxide and its interfaces. By fitting these results to the experimental data, the positron mobility was calculated to be mu(+)=1.20+/-0.09 cm(2)/V s. This value is two orders of magnitude larger than that previously reported by Kong [J. Appl. Phys. 70, 2874 (1991)], indicating distinct oxide properties. We address the mutually contradictory existing theoretical models, revise the present understanding of the positron behavior in MOS systems, and propose a general interpretation of available results from the literature. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Washington State Univ, Dept Phys, Pullman, WA 99164 USA. Delft Univ Technol, Interfac Reactor Inst, NL-2600 AG Delft, Netherlands. RP Petkov, MP (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 26 TC 5 Z9 5 U1 0 U2 1 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 JUL 15 PY 2002 VL 66 IS 4 AR 045322 DI 10.1103/PhysRevB.66.045322 PG 10 WC Physics, Condensed Matter SC Physics GA 583UA UT WOS:000177426400072 ER PT J AU Abazajian, KN Fuller, GM AF Abazajian, KN Fuller, GM TI Bulk QCD thermodynamics and sterile neutrino dark matter SO PHYSICAL REVIEW D LA English DT Article ID HADRON PHASE-TRANSITION; EARLY UNIVERSE; PRIMORDIAL NUCLEOSYNTHESIS; DENSITY PROFILES; X-RAY; WARM; HALO; SUBSTRUCTURE; QUARK; CONSTRAINTS AB We point out that the relic densities of singlet (sterile) neutrinos of interest in viable warm and cold dark matter scenarios depend on the characteristics of the QCD transition in the early universe. In the most promising of these dark matter scenarios, the production of the singlets occurs at or near the QCD transition. Since production of the singlets, their dilution, and the disappearance of weak scatterers occur simultaneously, we calculate these processes contemporaneously to obtain accurate predictions of relic sterile neutrino mass density. Therefore, a determination of the mass and superweak mixing of the singlet neutrino through, for example, its radiative decay, along with a determination of its contribution to the critical density, can provide insight into the finite-temperature QCD transition. C1 Fermilab Natl Accelerator Lab, NASA, Fermilab Astrophys Grp, Batavia, IL 60510 USA. Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA. RP Abazajian, KN (reprint author), Fermilab Natl Accelerator Lab, NASA, Fermilab Astrophys Grp, Box 500, Batavia, IL 60510 USA. NR 46 TC 60 Z9 60 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD JUL 15 PY 2002 VL 66 IS 2 AR 023526 DI 10.1103/PhysRevD.66.023526 PG 6 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 581HJ UT WOS:000177285600036 ER PT J AU Torres, DF Boldt, E Hamilton, T Loewenstein, M AF Torres, DF Boldt, E Hamilton, T Loewenstein, M TI Nearby quasar remnants and ultrahigh-energy cosmic rays SO PHYSICAL REVIEW D LA English DT Article ID SUPERMASSIVE BLACK-HOLES; RADIO-CONTINUUM SOURCES; ZATSEPIN-KUZMIN CUTOFF; ACTIVE GALACTIC NUCLEI; BRIGHT E/S0 GALAXIES; MAGNETIC-FIELDS; AIR SHOWERS; EMISSION; PROPAGATION; NEUTRINOS AB As recently suggested, nearby quasar remnants are plausible sites of black-hole based compact dynamos that could be capable of accelerating ultrahigh-energy cosmic rays (UHECRs). In such a model, UHECRs would originate at the nuclei of nearby dead quasars, those in which the putative underlying supermassive black holes are suitably spun-up. Based on galactic optical luminosity, morphological type, and redshift, we have compiled a small sample of nearby objects selected to be highly luminous, bulge-dominated galaxies, likely quasar remnants. The sky coordinates of these galaxies were then correlated with the arrival directions of cosmic rays detected at energies >40 EeV. An apparently significant correlation appears in our data. This correlation appears at closer angular scales than those expected when taking into account the deflection caused by typically assumed IGM or galactic magnetic fields over a charged particle trajectory. Possible scenarios producing this effect are discussed, as is the astrophysics of the quasar remnant candidates. We suggest that quasar remnants be also taken into account in the forthcoming detailed search for correlations using data from the Auger Observatory. C1 Princeton Univ, Dept Phys, Princeton, NJ 08544 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. RP Torres, DF (reprint author), Princeton Univ, Dept Phys, Princeton, NJ 08544 USA. RI Torres, Diego/O-9422-2016 OI Torres, Diego/0000-0002-1522-9065 NR 72 TC 20 Z9 20 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 JUL 15 PY 2002 VL 66 IS 2 AR 023001 DI 10.1103/PhysRevD.66.023001 PG 7 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 581HJ UT WOS:000177285600005 ER PT J AU Boldyrev, S Nordlund, A Padoan, P AF Boldyrev, S Nordlund, A Padoan, P TI Supersonic turbulence and structure of interstellar molecular clouds SO PHYSICAL REVIEW LETTERS LA English DT Article ID FULLY-DEVELOPED TURBULENCE; LOG-POISSON STATISTICS; MAGNETOHYDRODYNAMIC TURBULENCE; INTERMITTENCY; SIMULATIONS; VELOCITY; DENSITY; MODEL; FLOWS AB The interstellar medium provides a unique laboratory for highly supersonic, driven hydrodynamic turbulence. We propose a theory of such turbulence, test it by numerical simulations, and use the results to explain observational scaling properties of interstellar molecular clouds, the regions where stars are born. C1 Univ Calif Santa Barbara, Inst Theoret Phys, Santa Barbara, CA 93106 USA. Copenhagen Astron Observ, DK-2100 Copenhagen, Denmark. Theoret Astrophys Ctr, DK-2100 Copenhagen, Denmark. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Univ Calif Santa Barbara, Inst Theoret Phys, Santa Barbara, CA 93106 USA. RI Nordlund, Aake/M-4528-2014 OI Nordlund, Aake/0000-0002-2219-0541 NR 34 TC 63 Z9 65 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 EI 1079-7114 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUL 15 PY 2002 VL 89 IS 3 AR 031102 DI 10.1103/PhysRevLett.89.031102 PG 4 WC Physics, Multidisciplinary SC Physics GA 569JP UT WOS:000176599500006 PM 12144384 ER PT J AU Su, CH AF Su, CH TI Partial pressures of Te-2 and thermodynamic properties of Ga-Te system SO THERMOCHIMICA ACTA LA English DT Article DE partial pressures of Te-2; activities and partial molar enthalpy of mixing of Te; the Ga-Te system ID GALLIUM-TELLURIUM-SYSTEM; ALLOYS AB The partial pressures of Te-2 in equilibrium with Ga1-xTex samples were measured by optical absorption technique from 723 to 1373 K for compositions, x, between 0.333 and 0.612. To establish the relationship between the partial pressure of Te2 and the measured optical absorbance, the calibration runs of a pure Te sample were also conducted to determine the Beer's law constants. The partial pressures of Te, in equilibrium with the GaTe(s) and Ga2Te3(S) compounds, or the so-called three-phase curves, were established, From the partial pressures of Te-2 over the Ga-Te melts, partial molar enthalpy and entropy of mixing for Te were derived and they agree reasonably well with the published data. The activities of Te in the Ga-Te melts were also derived from the measured partial pressures of Te-2. These data agree well with most of the previous results except those determined by Predel et al. [Z. Metallkde. 66 (1975) 268]. The possible reason for the high activity of Te measured by Predel et al. [Z. Metallkde. 66 (1975) 268] for x < 0.60 is discussed. Published by Elsevier Science B.V. C1 NASA, George C Marshall Space Flight Ctr, Micrograv Sci & Applicat Dept, Sci Directorate, Huntsville, AL 35812 USA. RP Su, CH (reprint author), NASA, George C Marshall Space Flight Ctr, Micrograv Sci & Applicat Dept, Sci Directorate, SD46, Huntsville, AL 35812 USA. NR 23 TC 3 Z9 3 U1 6 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0040-6031 J9 THERMOCHIM ACTA JI Thermochim. Acta PD JUL 15 PY 2002 VL 390 IS 1-2 BP 21 EP 29 AR PII S0040-6031(02)00061-8 PG 9 WC Thermodynamics; Chemistry, Analytical; Chemistry, Physical SC Thermodynamics; Chemistry GA 572UL UT WOS:000176793300003 ER PT J AU Enzer, DG Hadley, PG Hughes, RJ Peterson, CG Kwiat, PG AF Enzer, DG Hadley, PG Hughes, RJ Peterson, CG Kwiat, PG TI Entangled-photon six-state quantum cryptography SO NEW JOURNAL OF PHYSICS LA English DT Article ID KEY DISTRIBUTION; BELL THEOREM; PROTOCOL; ATTACKS; STATES AB We have implemented the 'six-state' quantum cryptography protocol using polarization-entangled photon pairs, in which the polarization of each photon of a pair is measured in one of three randomly chosen bases. For a given amount of eavesdropping, this protocol results in a larger error rate than in four- or two-state protocols, but reduces the number of key-producing events. We have experimentally investigated several incoherent eavesdropping strategies, and verified the predicted enhancement in error rate. However, we demonstrate that for low error rates, the efficiency for secret key generation is higher when using the four- state protocol. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Los Alamos Natl Lab, Div Phys, Los Alamos, NM 87545 USA. Univ Illinois, Dept Phys, Urbana, IL 61801 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS-208-100, Pasadena, CA 91109 USA. EM kwiat@uiuc.edu NR 31 TC 13 Z9 13 U1 1 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 1367-2630 J9 NEW J PHYS JI New J. Phys. PD JUL 12 PY 2002 VL 4 AR 45 DI 10.1088/1367-2630/4/1/345 PG 8 WC Physics, Multidisciplinary SC Physics GA 573DK UT WOS:000176813900005 ER PT J AU Zwally, HJ Abdalati, W Herring, T Larson, K Saba, J Steffen, K AF Zwally, HJ Abdalati, W Herring, T Larson, K Saba, J Steffen, K TI Surface melt-induced acceleration of Greenland ice-sheet flow SO SCIENCE LA English DT Article ID SATELLITE RADAR INTERFEROMETRY; VELOCITY; SURGE AB Ice flow at a location in the equilibrium zone of the west-central Greenland Ice Sheet accelerates above the midwinter average rate during periods of summer melting. The near coincidence of the ice acceleration with the duration of surface melting, followed by deceleration after the melting ceases, indicates that glacial sliding is enhanced by rapid migration of surface meltwater to the ice-bedrock interface. Interannual variations in the ice acceleration are correlated with variations in the intensity of the surface melting, with larger increases accompanying higher amounts of summer melting. The indicated coupling between surface melting and ice-sheet flow provides a mechanism for rapid, large-scale, dynamic responses of ice sheets to climate warming. C1 NASA, Oceans & Ice Branch, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA Headquarters, Washington, DC 20546 USA. MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. Univ Colorado, Dept Aerosp Engn Sci, Boulder, CO 80309 USA. NASA, Raytheon Inc, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Colorado, CIRES, Boulder, CO 80309 USA. RP Zwally, HJ (reprint author), NASA, Oceans & Ice Branch, Goddard Space Flight Ctr, Code 971, Greenbelt, MD 20771 USA. EM jay.zwally@gsfc.nasa.gov RI Steffen, Konrad/C-6027-2013 OI Steffen, Konrad/0000-0001-8658-1026 NR 31 TC 558 Z9 569 U1 8 U2 116 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD JUL 12 PY 2002 VL 297 IS 5579 BP 218 EP 222 DI 10.1126/science.1072708 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 571UT UT WOS:000176738100032 PM 12052902 ER PT J AU Dai, ZR Bradley, JP Joswiak, DJ Brownlee, DE Hill, HGM Genge, MJ AF Dai, ZR Bradley, JP Joswiak, DJ Brownlee, DE Hill, HGM Genge, MJ TI Possible in situ formation of meteoritic nanodiamonds in the early Solar System SO NATURE LA English DT Article ID INTERPLANETARY DUST PARTICLES; PRESOLAR DIAMONDS; GRAINS; COMETS; CARBON AB Grains of dust that pre-date the Sun provide insights into their formation around other stars and into the early evolution of the Solar System(1-4). Nanodiamonds recovered from meteorites, which originate in asteroids, have been thought to be the most abundant type of presolar grain(3,4). If that is true, then nanodiamonds should be at least as abundant in comets, because they are thought to have formed further out in the early Solar System than the asteroid parent bodies, and because they should be more pristine(5-7). Here we report that nanodiamonds are absent or very depleted in fragile, carbon-rich interplanetary dust particles, some of which enter the atmosphere at speeds within the range of cometary meteors(8,9). One interpretation of the results is that some (perhaps most) nanodiamonds formed within the inner Solar System and are not presolar at all, consistent with the recent detection of nanodiamonds within the accretion discs of other young stars(10). An alternative explanation is that all meteoritic nanodiamonds are indeed presolar, but that their abundance decreases with heliocentric distance, in which case our understanding of large-scale transport and circulation within the early Solar System is incomplete(11). C1 Georgia Inst Technol, Sch Mat Sci & Engn, Atlanta, GA 30332 USA. Univ Washington, Dept Astron, Seattle, WA 98195 USA. NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. Nat Hist Museum, Dept Mineral, London SW7 5BD, England. RP Bradley, JP (reprint author), Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Mail Stop L-413,7000 East Ave, Livermore, CA 94550 USA. EM jbradley@igpp.ucllnl.org RI Dai, Zurong/E-6732-2010 NR 28 TC 92 Z9 94 U1 3 U2 17 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD JUL 11 PY 2002 VL 418 IS 6894 BP 157 EP 159 DI 10.1038/nature00897 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 571GV UT WOS:000176710400032 PM 12110882 ER PT J AU Ho, SP Smith, WL Huang, HL AF Ho, SP Smith, WL Huang, HL TI Retrieval of atmospheric-temperature and water-vapor profiles by used of combined satellite and ground-based infrared spectral-radiance measurements SO APPLIED OPTICS LA English DT Article ID SMOOTHING NOISY DATA; SPLINE FUNCTIONS; SOUNDER; ALGORITHM AB A nonlinear sounding retrieval algorithm is used to produce vertical-temperature and water-vapor profiles from coincident observations taken by the airborne High-resolution Interferometer Sounder (HIS) and the ground-based Atmospheric Emitted Radiance Interferometer (AERI) during the SUbsonic Contrails and Clouds Effects Special Study (SUCCESS). Also, clear sky Geostationary Operational Environmental Satellite (GOES) and AERI radiance measurements, achieved on a daily real-time basis at the Department of Energy's Oklahoma CART (Cloud and Radiation Testbed) site, are used to demonstrate the current profiling capability by use of simultaneous geostationary satellite and ground-based remote sensing observations under clear-sky conditions. The discrepancy principle, a method to find the proper smoothing parameters from the minimum value between the normalized spectral residual norm and the a priori upper bound, is used to demonstrate the feasibility and effectiveness of on-line simultaneous tuning of the multiple weighting. and smoothing parameters from the combined satellite/airborne and ground-based measurements for the temperature and water-vapor retrieval in this nonlinear-retrieval process. An objective method to determine the degrees of freedom (d.f.) of the observation signal is derived. The d.f. of the radiance signal for the combined GOES and AERI measurements is larger than that for either instrument alone; while the d.f. of the observation signal for the combined GOES and AERI measurements is larger than that for either instrument alone and of the combined GOES and AERI measurements. The use of simultaneous clear-sky AERI and GOES data now provides improved vertical temperature and moisture soundings on an hourly basis for use in the Atmospheric Radiation Measurement program [J. Appl. Meterol. 37, 875 (1998)]. (C) 2002 Optical Society of America. C1 Natl Ctr Atmospher Res, Boulder, CO 80307 USA. NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23665 USA. Univ Wisconsin, Cooperat Inst Meteorol Satellite Studies, Madison, WI 53706 USA. RP Ho, SP (reprint author), Natl Ctr Atmospher Res, POB 3000, Boulder, CO 80307 USA. EM spho@ucar.edu NR 34 TC 7 Z9 7 U1 0 U2 3 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD JUL 10 PY 2002 VL 41 IS 20 BP 4057 EP 4069 DI 10.1364/AO.41.004057 PG 13 WC Optics SC Optics GA 570RU UT WOS:000176672100001 PM 12141504 ER PT J AU Boldyrev, S Nordlund, A Padoan, P AF Boldyrev, S Nordlund, A Padoan, P TI Scaling relations of supersonic turbulence in star-forming molecular clouds SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : clouds; ISM : kinematics and dynamics; MHD; turbulence ID FULLY-DEVELOPED TURBULENCE; LOG-POISSON STATISTICS; INITIAL MASS FUNCTION; MAGNETOHYDRODYNAMIC TURBULENCE; INTERSTELLAR-MEDIUM; INTERMITTENCY; FLOWS; ORIGIN; MODEL AB We present a direct numerical and analytical study of driven supersonic magnetohydrodynamic turbulence that is believed to govern the dynamics of star-forming molecular clouds. We describe statistical properties of the turbulence by measuring the velocity difference structure functions up to the fifth order. In particular, the velocity power spectrum in the inertial range is found to be close to E-k similar to k(-1.74), and the velocity difference scales as [\Deltau\] similar to L-0.42. The results agree well with the Kolmogorov-Burgers analytical model suggested for supersonic turbulence. We then generalize the model to more realistic, fractal structure of molecular clouds and show that depending on the fractal dimension of a given molecular cloud, the theoretical value for the velocity spectrum spans the interval [-1.74, -1.89], while the corresponding window for the velocity difference scaling exponent is [-0.42, 0.78]. C1 Univ Calif Santa Barbara, Inst Theoret Phys, Santa Barbara, CA 93106 USA. Copenhagen Astron Observ, DK-2100 Copenhagen, Denmark. Theoret Astrophys Ctr, DK-2100 Copenhagen, Denmark. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Boldyrev, S (reprint author), Univ Calif Santa Barbara, Inst Theoret Phys, Santa Barbara, CA 93106 USA. RI Nordlund, Aake/M-4528-2014; OI Nordlund, Aake/0000-0002-2219-0541; Padoan, Paolo/0000-0002-5055-5800 NR 40 TC 88 Z9 88 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 JUL 10 PY 2002 VL 573 IS 2 BP 678 EP 684 DI 10.1086/340758 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 570MX UT WOS:000176663000018 ER PT J AU de Paz, AG Silich, SA Madore, BF Contreras, CS Zamorano, J Gallego, J AF de Paz, AG Silich, SA Madore, BF Contreras, CS Zamorano, J Gallego, J TI (CO)-C-12 mapping of the low-metallicity blue compact dwarf galaxy Markarian 86 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : dwarf; galaxies : evolution; galaxies : individual (Markarian 86); galaxies : starburst; radio lines : galaxies ID STAR-FORMATION; MOLECULAR GAS; RAY-EMISSION; CLOUDS; DRIVEN; BUBBLES; MRK-86; WINDS; CO AB We have mapped the (CO)-C-12 J = 1-0 and J = 2-1 line emission in Markarian 86, one of the most metal-deficient blue compact dwarf galaxies so far detected in (CO)-C-12. The (CO)-C-12 emission is distributed in a horseshoe-like structure that follows the locus of the most recent star formation regions. The minimum in molecular line emission corresponds to the position of an older, massive nuclear starburst. The H-2 mass of the galaxy [in the range of (0.4-5) x 10(7) M.] and its morphology have been compared with the predictions of hydrodynamic simulations of the evolution of the interstellar medium surrounding a nuclear starburst. These simulations suggest that the physical conditions in the gas swept out by the starburst could have led to the formation of the ring of molecular gas reported here. This result provides an attractive scenario for explaining the propagation (in a galactic scale) of the star formation in dwarf galaxies. C1 CALTECH, NASA IPAC Extragalact Database, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Inst Nacl Astrofis Opt & Elect, Puebla 72000, Mexico. Natl Acad Sci Ukraine, Main Astron Observ, UA-03680 Kiev, Golosiiv, Ukraine. Carnegie Inst Washington Observ, Pasadena, CA 91101 USA. Univ Complutense Madrid, Dept Astrofis, E-28040 Madrid, Spain. RP de Paz, AG (reprint author), CALTECH, NASA IPAC Extragalact Database, MS 100-22,770 S Wilson Ave, Pasadena, CA 91125 USA. RI Zamorano, Jaime/K-7706-2014; Gil de Paz, Armando/J-2874-2016 OI Zamorano, Jaime/0000-0002-8993-5894; Gil de Paz, Armando/0000-0001-6150-2854 NR 28 TC 9 Z9 9 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 10 PY 2002 VL 573 IS 2 BP L101 EP L105 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 570MY UT WOS:000176663100008 ER PT J AU Levenson, NA Krolik, JH Zycki, PT Heckman, TM Weaver, KA Awaki, H Terashima, Y AF Levenson, NA Krolik, JH Zycki, PT Heckman, TM Weaver, KA Awaki, H Terashima, Y TI Extreme X-ray iron lines in active galactic nuclei SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : Seyfert; quasars : general; X-rays : galaxies ID SEYFERT-GALAXIES; ASCA OBSERVATIONS; CIRCINUS GALAXY; TYPE-2 QSO; NGC 1068; EMISSION; IRAS-09104+4109; NGC-4945; NGC-1068; M51 AB We analyze X-ray spectra of heavily obscured (N-H > 10(24) cm(-2)) active galaxies obtained with Chandra, concentrating on the iron Kalpha fluorescence line. We measure very large equivalent widths in most cases, up to 5 keV in the most extreme example. The geometry of an obscuring torus of material near the active galactic nucleus (AGN) determines the Fe emission, which we model as a function of torus opening angle, viewing angle, and optical depth. The starburst/AGN composite galaxies in this sample require small opening angles. Starburst/AGN composite galaxies in general therefore present few direct lines of sight to their central engines. These composite galaxies are common, and their large covering fractions and heavy obscuration effectively hide their intrinsically bright X-ray continua. While few distant obscured AGNs have been identified, we propose to exploit their signature large Fe Kalpha equivalent widths to find more examples in X-ray surveys. C1 Univ Kentucky, Dept Phys & Astron, Lexington, KY 40506 USA. Johns Hopkins Univ, Dept Phys & Astron, Bloomberg Ctr, Baltimore, MD 21218 USA. Nicholaus Copernicus Astron Ctr, PL-00716 Warsaw, Poland. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Ehime Univ, Fac Sci, Dept Phys, Matsuyama, Ehime 7908577, Japan. Inst Space & Astronaut Sci, Kanagawa 2298510, Japan. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. RP Levenson, NA (reprint author), Univ Kentucky, Dept Phys & Astron, 177 Chem Phys Bldg, Lexington, KY 40506 USA. OI Levenson, Nancy A./0000-0003-4209-639X NR 39 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 JUL 10 PY 2002 VL 573 IS 2 BP L81 EP L84 DI 10.1086/342092 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 570MY UT WOS:000176663100004 ER PT J AU Molnar, SM Hughes, JP Donahue, M Joy, M AF Molnar, SM Hughes, JP Donahue, M Joy, M TI Chandra observations of unresolved X-ray sources around two clusters of galaxies SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : clusters : individual (Abell 1995, MS 0451.6-0305); X-rays : galaxies : clusters ID ABELL-1367; SEARCH AB We have searched for unresolved X-ray sources in the vicinity of two rich clusters of galaxies, Abell 1995 (A1995) and MS 0451.6-0305 (MS 0451), using the Chandra X-Ray Observatory. We detected significantly more unresolved sources around A1995 than expected based on the number of X-ray sources to the same flux limit detected in deep Chandra observations of blank fields. Previous studies have also found excess X-ray sources in the vicinity of several nearby clusters of galaxies using ROSAT and recently in more distant (z approximate to 0.5) clusters (RX J0030 and 3C 295) using Chandra. In contrast, we detect only 14 unresolved X-ray sources near MS 0451, which is consistent with the number expected from a cluster-free background. We determine the luminosity functions of the extra sources under the assumption that they are at the distance of their respective clusters. The characteristic luminosity of the extra sources around A1995 must be an order of magnitude fainter than that of the extra sources around RX J0030 and 3C 295. The apparent lack of extra sources around MS 0451 is consistent with its greater distance and the same characteristic luminosity as the A1995 sources. Hardness ratios suggest that, on average, the extra sources in A1995 may have harder spectra than those of RX J0030 and 3C 295. These results indicate that different classes of objects may dominate in different clusters, perhaps depending on the formation history and/or dynamical state of the accompanying cluster. C1 Rutgers State Univ, Dept Phys & Astron, Piscataway, NJ 08854 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. NASA, Dept Space Sci, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Molnar, SM (reprint author), Rutgers State Univ, Dept Phys & Astron, 136 Frelinghuysen Rd, Piscataway, NJ 08854 USA. RI Donahue, Megan/B-5361-2012 NR 27 TC 34 Z9 34 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 10 PY 2002 VL 573 IS 2 BP L91 EP L94 DI 10.1086/342086 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 570MY UT WOS:000176663100006 ER PT J AU Sahai, R Brillant, S Livio, M Grebel, EK Brandner, W Tingay, S Nyman, LA AF Sahai, R Brillant, S Livio, M Grebel, EK Brandner, W Tingay, S Nyman, LA TI Proper motions in the knotty, bipolar jet in Henize 2-90 SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; ISM : jets and outflows; planetary nebulae : individual (He 2-90); stars : AGB and post-AGB; stars : mass loss; stars : winds, outflows ID NEBULAE AB Using second-epoch Hubble Space Telescope imaging of the unusual, bipolar jet source He 2-90, we have discovered proper motions of 0."03 yr(-1) in the jet knots. Combining the proper motion with the knots' radial velocity measured from ground-based long-slit data, we find that the jet speed is roughly 150-360 km s(-1), the source distance is 1-2.5 kpc, and the inclination (to the sky plane) of the jet axis is theta = 10degrees-4degrees, although smaller values of theta and larger values of the jet speed and distance are not ruled out. A comparison of the [O III] and [N II] images shows the central obscuring disk structure directly. The disk, seen nearly edge-on, is embedded within a low-excitation circumstellar region extending from the equator up to a latitudinal angle of about +/-62degrees, with the remaining latitudinal angular space being occupied by a biconical high-excitation region whose symmetry axis is aligned along the jet. The jet is at least 1400 yr old; the knots are being ejected at the rate of one pair roughly every 35-45 yr (independent of the tilt angle and distance to He 2-90), and accretion is still occurring since the youngest jet material is only similar to10 yr old. The jet can be plausibly driven by an accretion disk around a low-mass companion in an eccentric orbit with a period of similar to40 yr, with increased accretion during periastron passage producing the jet knots. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. European So Observ, Santiago 19, Chile. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Max Planck Inst Astron, D-69117 Heidelberg, Germany. European So Observ, D-85748 Garching, Germany. CSIRO, Australia Telescope Natl Facil, Paul Wild Observ, Narrabri, NSW 2390, Australia. Chalmers Univ Technol, Onsala Space Observ, S-43992 Onsala, Sweden. RP Sahai, R (reprint author), CALTECH, Jet Prop Lab, MS 183-900,4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Tingay, Steven/B-5271-2013; OI /0000-0002-1891-3794 NR 12 TC 20 Z9 20 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 JUL 10 PY 2002 VL 573 IS 2 BP L123 EP L127 DI 10.1086/341969 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 570MY UT WOS:000176663100013 ER PT J AU Willacy, K Langer, WD Allen, M AF Willacy, K Langer, WD Allen, M TI HI: A chemical tracer of turbulent diffusion in molecular clouds SO ASTROPHYSICAL JOURNAL LA English DT Article DE diffusion; ISM : abundances; ISM : clouds; ISM : molecules; molecular processes; turbulence ID DENSE INTERSTELLAR CLOUDS; ATOMIC CARBON; DARK CLOUDS; CO; ABUNDANCE; CHEMISTRY; H-2 AB Turbulence is widespread in the interstellar medium, and turbulent diffusion has been suggested as a means of accounting for the lower than expected O-2 abundance observed in molecular clouds by the Submillimeter Wave Astronomy Satellite. Here we present the results of new chemical models of clouds incorporating turbulent diffusion, together with gas-grain interactions and H-2 and CO self-shielding. We find H I to be a very sensitive tracer of the diffusion process, with H I/H-2 larger in the interior than predicted by static models. Our model may explain observations of H I/H-2 in cold cores. The model results for other species, e. g., O, O-2, H2O, C, and CO, are also consistent with available observations. This work demonstrates the potential importance of chemical studies in the elucidation of turbulent processes in the interstellar medium. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Willacy, K (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 169-506, Pasadena, CA 91109 USA. NR 26 TC 12 Z9 12 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 JUL 10 PY 2002 VL 573 IS 2 BP L119 EP L122 DI 10.1086/342053 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 570MY UT WOS:000176663100012 ER PT J AU Gitelson, AA Stark, R Grits, U Rundquist, D Kaufman, Y Derry, D AF Gitelson, AA Stark, R Grits, U Rundquist, D Kaufman, Y Derry, D TI Vegetation and soil lines in visible spectral space: a concept and technique for remote estimation of vegetation fraction SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID LEAF-AREA INDEX; REFLECTANCE MEASUREMENTS; CHLOROPHYLL-A; EOS-MODIS; LEAVES; WHEAT; GREEN; LIMITATIONS; INFORMATION; MANAGEMENT AB The goal of this study is to investigate the information content of reflectance spectra of crops in the visible and near infrared range of the spectrum and develop a technique for remote estimation of vegetation fraction (VF). For four wheat species with VF 100% in a wide range of pigment contents and compositions, a high degree of covariance was found for paired reflectances (R) at 550 nm versus 700 nm (R-550 versus R-700) and 500 nm versus 670 nm (R-500 versus R-670). Both relationships, defined as 'vegetation lines', were linear with determination coefficients r(2) >0.9 and the plotted points were tightly clustered. Using the same coordinates to plot reflectances for a variety of soils, a high degree of covariance (r(2)>0.94) and a distinct 'soil line' were found. The vegetation and soil lines define a two-dimensional spectral construct within which canopy reflectances, regardless of VF, may be located. Based on these optical properties of vegetation and soils, an attempt was made to estimate VF remotely for selected plant canopies. It is suggested that the coordinate location within the constructs, as defined by reflectances at 500 nm and 670 nm as well as at 550 nm and 700 nm, be used to measure VF. Algorithms for VF assessment in wheat for a wide range of soil brightness were devised and validated. The root mean square error (RMSE) of VF prediction was less than 10%. The technique was also validated by means of independent datasets taken above cornfields in Nebraska. The RMSE of VF prediction did not exceed 9.7%. C1 Univ Nebraska, Ctr Adv Land Management Informat Technol, Sch Nat Resource Sci, Lincoln, NE 68588 USA. Ben Gurion Univ Negev, Dept Geol & Environm Sci, IL-84105 Beer Sheva, Israel. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Gitelson, AA (reprint author), Univ Nebraska, Ctr Adv Land Management Informat Technol, Sch Nat Resource Sci, Lincoln, NE 68588 USA. RI Gitelson, Anatoly/G-3452-2012 NR 51 TC 43 Z9 52 U1 0 U2 11 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 JUL 10 PY 2002 VL 23 IS 13 BP 2537 EP 2562 DI 10.1080/01431160110107806 PG 26 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 574AE UT WOS:000176865500002 ER PT J AU Nirala, ML Cracknell, AP AF Nirala, ML Cracknell, AP TI Microwave measurement of rain and sea surface temperature by the TRMM Microwave Imager (TMI) SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID MODEL AB The Tropical Rainfall Measuring Mission (TRMM) is important for studies of the global hydrological cycle and for testing the realism of climate models and their ability to Simulate and predict climate accurately; the effect of El Nino, on climate could be addressed as well. This paper investigates the microwave rain measurement using satellite data from the TRMM Microwave Imager (TMI). The physical bases of rainfall estimation algorithms, vertical Structure of rain and its physical processes are explained. The algorithms for processing TMI radiance and brightness temperature data are presented. Various rain maps and sea Surface temperature (SST) maps are produced using TMI microwave data. The performance, calibration, analysis of results and sources of errors in the averaged monthly surface rain rate estimation are discussed. C1 Univ Dundee, Dept Appl Phys & Elect & Mech Engn, Dundee DD1 4HN, Scotland. RP Nirala, ML (reprint author), NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Code 974, Greenbelt, MD 20771 USA. NR 17 TC 3 Z9 3 U1 0 U2 0 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 JUL 10 PY 2002 VL 23 IS 13 BP 2673 EP 2691 DI 10.1080/01431160110071941 PG 19 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 574AE UT WOS:000176865500008 ER PT J AU Wang, MH AF Wang, MH TI The Rayleigh lookup tables for the SeaWiFS data processing: accounting for the effects of ocean surface roughness SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID WATER-LEAVING RADIANCE; ATMOSPHERIC DIFFUSE TRANSMITTANCE; COLOR SENSORS; SPECTRAL REFLECTANCE; WHITECAPS AB In the atmospheric correction of ocean colour remote sensing, it is important to account for the effects of ocean surface roughness (wind speed) in the computation of Rayleigh radiance lookup tables, in particular, for the large solar and/or sensor zenith angles (> similar to60degrees). In the paper, both simulated and the SeaWiFS-retrieved results that demonstrate the effects of the ocean surface wind speed on the Rayleigh radiance computations for the various solar and sensor-viewing geometries as well as on the performance of atmospheric corrections are presented and discussed. An improved set of Rayleigh lookup tables, in which the Rayleigh scattering radiance is also a function of the sea surface wind speed. were generated and implemented into the SeaWiFS data processing system in May 2000. C1 Univ Maryland, Goddard Space Flight Ctr, NASA, Greenbelt, MD 20771 USA. RP Wang, MH (reprint author), Univ Maryland, Goddard Space Flight Ctr, NASA, Code 970-2, Greenbelt, MD 20771 USA. RI Wang, Menghua/F-5631-2010 OI Wang, Menghua/0000-0001-7019-3125 NR 19 TC 49 Z9 50 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 JUL 10 PY 2002 VL 23 IS 13 BP 2693 EP 2702 DI 10.1080/01431160110115591 PG 10 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 574AE UT WOS:000176865500009 ER PT J AU Ushio, T Heckman, S Driscoll, K Boccippio, D Christian, H Kawasaki, Z AF Ushio, T Heckman, S Driscoll, K Boccippio, D Christian, H Kawasaki, Z TI Cross-sensor comparison of the Lightning Imaging Sensor (LIS) SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID SATELLITE; INTRACLOUD; NETWORK; FLASH AB The mapping of the lightning optical pulse detected by the Lightning Imaging Sensor (LIS) is compared with the radiation sources by Lightning Detection and Ranging (LDAR) at KSC and the National Lightning Detection Network (NLDN). Flash-based comparisons are done for the 15 August 1998 case including 122 flashes. The temporal and spatial differences are examined. For ground flash, the time difference of the first LDAR source and first LIS event has a mean of 0.23 s and the total duration of the flash has a mean of 0.28 s, compared to 0.56 s by LDAR. The LIS records the subsequent return stroke or K-change component. For cloud flash, the time difference has a mean of 0.2 s and the total duration of the flash has a mean of 0.38 s, compared to 0.44 s by LDAR. The LIS also records cloud flashes at higher altitude. The location differences are about 4 km for cloud flash and 12 km for ground flash. C1 Univ Osaka Prefecture, Dept Aerosp Engn, Sakai, Osaka 5998531, Japan. NASA, George C Marshall Space Flight Ctr, Global Hydrol & Climate Ctr, Huntsville, AL 35805 USA. Osaka Univ, Dept Commun Engn, Suita, Osaka 5650871, Japan. RP Ushio, T (reprint author), Univ Osaka Prefecture, Dept Aerosp Engn, 1-1 Gakuencho, Sakai, Osaka 5998531, Japan. RI Ushio, Tomoo/G-6915-2011 NR 15 TC 4 Z9 5 U1 0 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 JUL 10 PY 2002 VL 23 IS 13 BP 2703 EP 2712 DI 10.1080/01431160110107789 PG 10 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 574AE UT WOS:000176865500010 ER PT J AU Weaver, P AF Weaver, P TI Keep seats facing forward SO AVIATION WEEK & SPACE TECHNOLOGY LA English DT Letter C1 NASA, Langley Res Ctr, FAA R&D Field Off, Hampton, VA 23665 USA. RP Weaver, P (reprint author), NASA, Langley Res Ctr, FAA R&D Field Off, Hampton, VA 23665 USA. NR 0 TC 0 Z9 0 U1 1 U2 1 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 JUL 8 PY 2002 VL 157 IS 2 BP 6 EP 6 PG 1 WC Engineering, Aerospace SC Engineering GA 572FU UT WOS:000176763700003 ER PT J AU Mitrofanov, I Anfimov, D Kozyrev, A Litvak, M Sanin, A Tret'yakov, V Krylov, A Shvetsov, V Boynton, W Shinohara, C Hamara, D Saunders, RS AF Mitrofanov, I Anfimov, D Kozyrev, A Litvak, M Sanin, A Tret'yakov, V Krylov, A Shvetsov, V Boynton, W Shinohara, C Hamara, D Saunders, RS TI Maps of subsurface hydrogen from the high energy neutron detector, Mars Odyssey SO SCIENCE LA English DT Article ID ORBITER LASER ALTIMETER; WATER; ICE AB After 55 days of mapping by the High Energy Neutron Detector onboard Mars Odyssey, we found deficits of high-energy neutrons in the southern highlands and northern lowlands of Mars. These deficits indicate that hydrogen is concentrated in the subsurface. Modeling suggests that water ice rich layers that are tens of centimeters in thickness provide one possible fit to the data. C1 Inst Space Res, Moscow 117997, Russia. Joint Inst Nucl Res, Dubna 141980, Russia. Univ Arizona, Tucson, AZ 85721 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Mitrofanov, I (reprint author), Inst Space Res, Moscow 117997, Russia. NR 15 TC 251 Z9 260 U1 2 U2 12 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD JUL 5 PY 2002 VL 297 IS 5578 BP 78 EP 81 DI 10.1126/science.1073616 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 571HB UT WOS:000176711000035 PM 12040089 ER PT J AU Boynton, WV Feldman, WC Squyres, SW Prettyman, TH Bruckner, J Evans, LG Reedy, RC Starr, R Arnold, JR Drake, DM Englert, PAJ Metzger, AE Mitrofanov, I Trombka, JI d'Uston, C Wanke, H Gasnault, O Hamara, DK Janes, DM Marcialis, RL Maurice, S Mikheeva, I Taylor, GJ Tokar, R Shinohara, C AF Boynton, WV Feldman, WC Squyres, SW Prettyman, TH Bruckner, J Evans, LG Reedy, RC Starr, R Arnold, JR Drake, DM Englert, PAJ Metzger, AE Mitrofanov, I Trombka, JI d'Uston, C Wanke, H Gasnault, O Hamara, DK Janes, DM Marcialis, RL Maurice, S Mikheeva, I Taylor, GJ Tokar, R Shinohara, C TI Distribution of hydrogen in the near surface of Mars: Evidence for subsurface ice deposits SO SCIENCE LA English DT Article ID GROUND ICE; WATER AB Using the Gamma-Ray Spectrometer on the Mars Odyssey, we have identified two regions near the poles that are enriched in hydrogen. The data indicate the presence of a subsurface layer enriched in hydrogen overlain by a hydrogen-poor layer. The thickness of the upper layer decreases with decreasing distance to the pole, ranging from a column density of about 150 grams per square centimeter at -42degrees latitude to about 40 grams per square centimeter at -77degrees. The hydrogen-rich regions correlate with regions of predicted ice stability. We suggest that the host of the hydrogen in the subsurface layer is ice, which constitutes 35 +/- 15% of the layer by weight. C1 Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Cornell Univ, Ctr Radiophys & Space Res, Ithaca, NY 14853 USA. Max Planck Inst Chem, D-55020 Mainz, Germany. Comp Sci Corp, Sci Programs, Lanham, MD 20706 USA. Univ New Mexico, Inst Meteorit, Albuquerque, NM 87131 USA. Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. Univ Calif San Diego, Dept Chem, La Jolla, CA 92093 USA. TechSource, Santa Fe, NM 87505 USA. Victoria Univ Wellington, Wellington, New Zealand. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Russian Acad Sci, Inst Space Res, Moscow, Russia. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Ctr Etud Spatiale Rayonnements, Toulouse, France. Observ Midi Pyrenees, F-31400 Toulouse, France. Univ Hawaii, Honolulu, HI 96822 USA. RP Boynton, WV (reprint author), Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. RI Gasnault, Olivier/F-4327-2010; OI Gasnault, Olivier/0000-0002-6979-9012; Reedy, Robert/0000-0002-2189-1303; Prettyman, Thomas/0000-0003-0072-2831 NR 21 TC 570 Z9 583 U1 8 U2 53 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD JUL 5 PY 2002 VL 297 IS 5578 BP 81 EP 85 DI 10.1126/science.1073722 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 571HB UT WOS:000176711000036 PM 12040090 ER PT J AU Mankins, JC AF Mankins, JC TI Approaches to strategic research and technology (R&T) analysis and road mapping SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 52nd Congress of the International-Astronautical-Federation CY OCT 01, 2001 CL TOULOUSE, FRANCE SP Int Astronautical Fererat, Int acad Astronaut, Int Inst Space Law AB Increasingly, the timely and successful incorporation of innovative technologies into new systems is a critical factor in their success or failure. This is true for both commercial and government space missions. In addition, continuing progress in methodologies that may enable the effective identification of long-term technology needs and opportunities-and the guidance of ongoing research and technology (R&T) programs to address them-is vital to progress in space exploration and commercial development. NASA's long-standing use of technology readiness levels (TRLs) is one such approach. These technology discipline-independent metrics provide a valuable tool in technology management at all levels in an organization. However, TRLs provide only the basic guideposts for R&T management: information on the current and desired level of maturity of a technology for a particular application. In order to succeed over the longer term, additional methodologies are needed, including those which allow the identification of anticipated uncertainty in planned R&T programs, as well as approaches that permit the identification of overall technology-derived uncertainty in future space systems developments. This paper provides a preliminary discussion of this critical subject, including an overview of the history and the current practices of the TRL approach. In addition, the paper presents a recently-formulated strategic technology management approach that attempts to address the question of uncertainty in technology development and applications: the Integrated Technology Analysis Methodology (ITAM). The paper concludes with a discussion of a ft"re directions for space technology management, and how these tools might be used to facilitate coordination and discussions in an international setting. (C) 2002 International Astronautical Federation. Published by Elsevier Science Ltd. All rights reserved. C1 NASA Headquarters, Off Space Flight, Adv Projects Off, Washington, DC USA. RP Mankins, JC (reprint author), NASA Headquarters, Off Space Flight, Adv Projects Off, Washington, DC USA. NR 9 TC 20 Z9 20 U1 2 U2 9 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD JUL-NOV PY 2002 VL 51 IS 1-9 BP 3 EP 21 AR PII S0094-5765(02)00083-8 DI 10.1016/S0094-5765(02)00083-8 PG 19 WC Engineering, Aerospace SC Engineering GA 571MJ UT WOS:000176720900002 ER PT J AU De Paula, RP Edwards, CD Flamini, E AF De Paula, RP Edwards, CD Flamini, E TI Evolution of the communications systems and technology for Mars exploration SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 52nd Congress of the International-Astronautical-Federation CY OCT 01, 2001 CL TOULOUSE, FRANCE SP Int Astronautical Fererat, Int acad Astronaut, Int Inst Space Law AB This paper will provide an overview of the evolution of the of the telecommunication systems used for Mars exploration by discussing the past, present and potential future systems. The required technology and limiting factors will be discussed. The goal of NASA's Mars Exploration Project is to support seamless flow of information from Mars to Earth (MTE) from Science Orbiters, Telecommunication Orbiters, and Surface Landers. The anticipated Sur-face Landers will include a diverse set of in situ spacecraft, ranging from large, highly mobile rovers with considerable landed mass and power, to small, extremely energy constrained "scout-class" missions with little or no direct-to-Earth telecommunications link capability. The paper discusses the status of current telecommunication links using X- and Ka-band for MTE and UHF for proximity links (surface-to-orbiter). The paper also mentions potential future generation communication links such as optical communications. The development of the Mars telecommunications infrastructure is part of NASA's plan to establish a presence in Mars and eventually throughout the solar system. Our presence in Mars over the next two decades will largely be a function of our Mars missions and the evolution of our deep space communications capabilities. (C) 2002 International Astronautical Federation. Published by Elsevier Science Ltd. All rights reserved. C1 NASA Headquarters, Mars Program Off, Washington, DC 20546 USA. RP De Paula, RP (reprint author), NASA Headquarters, Mars Program Off, Washington, DC 20546 USA. NR 2 TC 2 Z9 2 U1 0 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD JUL-NOV PY 2002 VL 51 IS 1-9 BP 207 EP 212 AR PII S0094-5765(02)00062-0 DI 10.1016/S0094-5765(02)00062-0 PG 6 WC Engineering, Aerospace SC Engineering GA 571MJ UT WOS:000176720900022 ER PT J AU Hubbard, GS Naderi, FM Garvin, JB AF Hubbard, GS Naderi, FM Garvin, JB TI Following the water, the new program for Mars exploration SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 52nd Congress of the International-Astronautical-Federation CY OCT 01, 2001 CL TOULOUSE, FRANCE SP Int Astronautical Fererat, Int acad Astronaut, Int Inst Space Law AB In the wake of the loss of Mars Climate Orbiter and Mars Polar Lander in late 1999, NASA embarked on a major review of the failures and subsequently restructured all aspects of what was then called the Mars Surveyor Program - now renamed the Mars Exploration Program. This paper presents the process and results of this reexamination and defines a new approach which we have called "Program System Engineering". Emphasis is given to the scientific, technological, and programmatic strategies that were used to shape the new Program. A scientific approach known as "follow the water" is described, as is an exploration strategy we have called "seek - in situ sample". An overview of the mission queue from continuing Mars Global Surveyor through a possible Mars Sample Return Mission launch in 2011 is provided. In addition, key proposed international collaborations, especially those between NASA, CNES and ASI are outlined, as is an approach for a robust telecommunications infrastructure. (C) 2002 Published by Elsevier Science Ltd. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Hubbard, GS (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 6 TC 13 Z9 13 U1 1 U2 9 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD JUL-NOV PY 2002 VL 51 IS 1-9 BP 337 EP 350 AR PII S0094-5765(02)00067-X DI 10.1016/S0094-5765(02)00067-X PG 14 WC Engineering, Aerospace SC Engineering GA 571MJ UT WOS:000176720900036 PM 12583389 ER PT J AU Rayman, MD AF Rayman, MD TI The Deep Space 1 extended mission: Challenges in preparing for an encounter with comet Borrelly SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 52nd Congress of the International-Astronautical-Federation CY OCT 01, 2001 CL TOULOUSE, FRANCE SP Int Astronautical Fererat, Int acad Astronaut, Int Inst Space Law ID DEEP-SPACE-1 AB Following the successful conclusion of its 11-month primary mission in September 1999, Deep Space I embarked on an ambitious extended mission. The spacecraft is using its Ion propulsion system to help deliver it to an encounter with comet 19P/Borrelly in September 2001. Along the way, the very small operations team has faced numerous challenges with an aging and debilitated spacecraft that was not designed for a comet encounter. The progress in reaching comet Borrelly is described as are the plans for attempting, to return science data from this high-risk conclusion to the extended mission. (C) 2002 Published by Elsevier Science Ltd. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Rayman, MD (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 11 TC 9 Z9 9 U1 1 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD JUL-NOV PY 2002 VL 51 IS 1-9 BP 507 EP 516 AR PII S0094-5765(02)00070-X DI 10.1016/S0094-5765(02)00070-X PG 10 WC Engineering, Aerospace SC Engineering GA 571MJ UT WOS:000176720900050 ER PT J AU Brewer, DA Barth, JL LaBel, KA Kauffman, WJ Giffin, G AF Brewer, DA Barth, JL LaBel, KA Kauffman, WJ Giffin, G TI NASA'S Living with a Star program: Science with relevance SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 52nd Congress of the International-Astronautical-Federation CY OCT 01, 2001 CL TOULOUSE, FRANCE SP Int Astronautical Fererat, Int acad Astronaut, Int Inst Space Law AB NASA has initiated the Living with a Star (LWS) Program to develop the scientific understanding to address the aspects of the connected Sun-Earth system that affect life and society. A goal of the program is to bridge the gap between science, engineering, and user application communities by addressing scientific questions that pertain to human radiation exposure, climate change, and technological systems. This will enable future science, operational, and commercial objectives in space and atmospheric environments by improving engineering approaches to the accommodation and/or mitigation of the effects of solar variability on these systems. The formulation of the LWS Program architecture and implementation plan is currently in progress with inputs from the science and engineering communities. There are plans for two groups of science spacecraft: (a) solar dynamics elements that observe the Sun and track disturbances originating there and (b) geospace elements located between the Sun and the Earth and around the Earth to measure downstream effects the geospace response to changes in solar activity. Plans also include a data analysis component to improve scientific understanding, and a series of Space Environment Testbeds to provide infusion of the improved understanding to the design and operations of future missions. The LWS Program is developing partnerships with other US and International agencies and industry to augment existing capabilities. The full paper will give an overview of the program architecture and the implementation and partnering plan for LWS. Published by Elsevier Science Ltd. C1 NASA Headquarters, Washington, DC 20546 USA. RP Brewer, DA (reprint author), NASA Headquarters, Washington, DC 20546 USA. NR 6 TC 0 Z9 0 U1 1 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD JUL-NOV PY 2002 VL 51 IS 1-9 BP 609 EP 616 AR PII S0094-5765(02)00053-X DI 10.1016/S0094-5765(02)00053-X PG 8 WC Engineering, Aerospace SC Engineering GA 571MJ UT WOS:000176720900060 ER PT J AU Palosz, B Grzanka, E Gierlotka, S Stel'Makh, S Pielaszek, R Bismayer, U Neuefeind, J Weber, HP Palosz, W AF Palosz, B Grzanka, E Gierlotka, S Stel'Makh, S Pielaszek, R Bismayer, U Neuefeind, J Weber, HP Palosz, W TI Diffraction studies of nanocrystals: Theory and experiment SO ACTA PHYSICA POLONICA A LA English DT Article; Proceedings Paper CT 4th International School and Symposium on Physics in Materials Science (ISSPMS 01) CY SEP 23-29, 2001 CL JASZOWIEC, POLAND SP Inst Atom Energy, Warsaw Univ Technol, Dept Mat Sci & Engn ID X-RAY-DIFFRACTION; SURFACE-TENSION; SMALL PARTICLES; LATTICE-PARAMETER; CDSE NANOCRYSTALS; SIZE DEPENDENCE; GOLD PARTICLES; ATOM CLUSTERS; HIGH-PRESSURE; STRESS AB Based on theoretical calculations of powder diffraction data it is shown that the assumption of the infinite crystal lattice for small particles is not justified, leads to significant changes of the diffraction patterns, and may lead to erroneous interpretation of the experimental results. An alternate evaluation of diffraction data of nanoparticles, based on the so-called "apparent lattice parameter", alp, is proposed. C1 High Presure Res Ctr UNIPRESS, PL-01142 Warsaw, Poland. Univ Warsaw, Inst Expt Phys, PL-00681 Warsaw, Poland. Univ Hamburg, Mineral & Petrog Inst, D-20146 Hamburg, Germany. DESY, HASYLAB, D-22603 Hamburg, Germany. European Synchrotron Radiat Facil, SNBL, F-38043 Grenoble, France. NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, Huntsville, AL 35812 USA. RP High Presure Res Ctr UNIPRESS, Skolowska 29-37, PL-01142 Warsaw, Poland. EM palosz@unipress.waw.pl RI Neuefeind, Joerg/D-9990-2015 OI Neuefeind, Joerg/0000-0002-0563-1544 NR 40 TC 31 Z9 31 U1 1 U2 4 PU POLISH ACAD SCIENCES INST PHYSICS PI WARSAW PA AL LOTNIKOW 32-46, PL-02-668 WARSAW, POLAND SN 0587-4246 EI 1898-794X J9 ACTA PHYS POL A JI Acta Phys. Pol. A PD JUL PY 2002 VL 102 IS 1 BP 57 EP 82 PG 26 WC Physics, Multidisciplinary SC Physics GA 580RC UT WOS:000177246700006 ER PT J AU Khorrami, MR Singer, BA Berkman, ME AF Khorrami, MR Singer, BA Berkman, ME TI Time-accurate simulations and acoustic analysis of slat free shear layer SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT AIAA/CEAS 7th Aeroacoustics Conference CY MAY 28-30, 2001 CL MAASTRICHT, NETHERLANDS SP Amer Inst Aeronaut & Astronaut, CEAS ID TRAILING-EDGE; COMPUTATIONS; FLOW AB A detailed computational aeroacoustic analysis of a high-lift flowfield is performed. Time-accurate Reynolds averaged Navier-Stokes computations simulate the free shear layer that originates from the slat cusp. Both unforced and forced cases are studied. Preliminary results show that the shear layer is a good amplifier of disturbances in the low- to midfrequency range. The Ffowcs Williams and Hawkings equation is solved to determine the acoustic field using the unsteady flow data from the Reynolds averaged Navier-Stokes calculations. The noise radiated from the excited shear layer has a spectral shape qualitatively similar to that obtained from measurements in a corresponding experimental study of the high-lift system. C1 NASA, Langley Res Ctr, Computat Modeling & Simulat Branch, Hampton, VA 23681 USA. High Technol Corp, Hampton, VA 23666 USA. RP Khorrami, MR (reprint author), NASA, Langley Res Ctr, Computat Modeling & Simulat Branch, Hampton, VA 23681 USA. NR 18 TC 29 Z9 30 U1 1 U2 2 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 JUL PY 2002 VL 40 IS 7 BP 1284 EP 1291 DI 10.2514/2.1817 PG 8 WC Engineering, Aerospace SC Engineering GA 569WA UT WOS:000176624400004 ER PT J AU DeBonis, JR Scott, JN AF DeBonis, JR Scott, JN TI Large-eddy simulation of a turbulent compressible round jet SO AIAA JOURNAL LA English DT Article AB A large-eddy simulation (LES) of a high-Reynolds-number jet was performed. A numerical scheme that is uniformly fourth-order accurate in time and space was used to solve the Favre-filtered Navier-Stokes equations. The subgrid-scale stresses were computed using a compressible form of Smagorinsky's model. A cold Mach 1.4 nozzle with a Reynolds number of 1.2 x 10(6) was simulated. In contrast to similar studies, the entire nozzle geometry including the nozzle lip was modeled. The LES simulation accurately captures the physics of the turbulent flow. The agreement with experimental data is relatively good and improves on results in the current literature. This improvement can be attributed to the numerical scheme and the modeling of the nozzle. In addition, a two-point correlation technique was used to quantify the turbulent structures in the jet mixing layer and showed that computational techniques can be used to characterize such structures for application to Lighthill's acoustic analogy. Two-point space correlations were used to obtain a measure of the integral length scale, which proved to be approximately (1)/D-2(j). Two-point space-time correlations were used to estimate the convection velocity for the turbulent structures. This velocity estimates ranged from 0.57 to 0.71 U-j and is in agreement with theory. C1 NASA, John H Glenn Res Ctr, Nozzle Branch, Cleveland, OH 44135 USA. NASA, John H Glenn Res Ctr, Dept Aerosp Engn & Aviat, Cleveland, OH 44135 USA. RP DeBonis, JR (reprint author), NASA, John H Glenn Res Ctr, Nozzle Branch, Cleveland, OH 44135 USA. NR 23 TC 29 Z9 29 U1 1 U2 4 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 JUL PY 2002 VL 40 IS 7 BP 1346 EP 1354 DI 10.2514/2.1794 PG 9 WC Engineering, Aerospace SC Engineering GA 569WA UT WOS:000176624400011 ER PT J AU Seifert, A Pack, LG AF Seifert, A Pack, LG TI Active flow separation control on wall-mounted hump at high Reynolds numbers SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT AIAA 30th Fluid Dynamics Conference CY JUN 28-JUL 01, 1999 CL NORFOLK, VIRGINIA SP Amer Inst Aeronaut & Astronaut ID PERIODIC EXCITATION; OSCILLATORY CONTROL; DELAY AB An active separation control experiment was conducted in a cryogenic pressurized wind tunnel on a wall-mounted bump at chord Reynolds numbers from 2.4 x 10(6) to 26 x 10(6) and a Mach number of 0.25. The model simulates the upper surface of a 20% thick Glauert-Goldschmied-type airfoil at zero incidence. The turbulent boundary layer of the tunnel sidewall flows over the model and eliminates laminar-turbulent transition from the problem. Indeed, the Reynolds number either based on the chord or boundary-layer thickness had a negligible effect on the flow and its control. Without control, a large turbulent separation bubble is formed at the lee side of the model. Periodic excitation and steady suction or blowing were applied to eliminate gradually the separation bubble. Detailed effects due to variations in the excitation frequency, amplitude, and the steady mass flux are described and compared to those of steady suction or blowing. It was found that the amplitude of the most effective frequency for separation control is rapidly attenuated in the reattachment region. The superposition of weak steady suction enhances the receptivity of the separated shear layer to the fundamental excitation frequency and, therefore, the effectiveness of the periodic excitation, whereas weak steady blowing promotes the generation of higher harmonics and reduces the excitation effectiveness. Separation control using periodic excitation and weak suction are similar in both effectiveness and dynamics, whereas steady blowing generates steadier flow but is of inferior effectiveness and is abrupt in nature and is, therefore, not suitable for closed-loop control. The data set enhances the understanding of active separation control at high Reynolds numbers and is a proper validation case for unsteady numerical design tools. C1 Tel Aviv Univ, Dept Fluid Mech & Heat Transfer, Fac Engn, IL-69978 Ramat Aviv, Israel. NASA, Langley Res Ctr, Flow Phys & Control Branch, Hampton, VA USA. RP Seifert, A (reprint author), Tel Aviv Univ, Dept Fluid Mech & Heat Transfer, Fac Engn, IL-69978 Ramat Aviv, Israel. NR 26 TC 56 Z9 58 U1 0 U2 4 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 JUL PY 2002 VL 40 IS 7 BP 1363 EP 1372 DI 10.2514/2.1796 PG 10 WC Engineering, Aerospace SC Engineering GA 569WA UT WOS:000176624400013 ER PT J AU Papalexandris, MV Milman, MH Levine, MB AF Papalexandris, MV Milman, MH Levine, MB TI Nodal temperature estimation algorithms for nonlinear thermal network models SO AIAA JOURNAL LA English DT Article ID OPTIMIZATION PROBLEMS AB Algorithms for estimating temperatures at arbitrary nodes of steady-state thermal network models, given noisy measured values of a subset of the nodes of the network, are described. Applications where temperature estimation is desired include correlation of test and analysis results, thermal-stress estimation, and others. An optimization problem is formulated to recover the temperatures at the unobservable nodes. This problem is an example of nonlinear, least-squares minimization with a single quadratic constraint (imposed by the measured data) and is solved with the method of Lagrange multipliers. New algorithms are developed that find local minima of the cost functional through a Newton-type iteration procedure. At each iteration a least-squares problem with a quadratic inequality is solved with a fast and memory-efficient method. The proposed algorithms are shown to be at least an order of magnitude faster than standard algorithms. Their accuracy and speed are examined through a series of tests on thermal models from ongoing NASA missions. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Papalexandris, MV (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 24 TC 4 Z9 4 U1 1 U2 2 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 JUL PY 2002 VL 40 IS 7 BP 1451 EP 1461 DI 10.2514/2.1808 PG 11 WC Engineering, Aerospace SC Engineering GA 569WA UT WOS:000176624400024 ER PT J AU Berdichevsky, DB Farrugia, CJ Thompson, BJ Lepping, RP Reames, DV Kaiser, ML Steinberg, JT Plunkett, SP Michels, DJ AF Berdichevsky, DB Farrugia, CJ Thompson, BJ Lepping, RP Reames, DV Kaiser, ML Steinberg, JT Plunkett, SP Michels, DJ TI Halo-coronal mass ejections near the 23rd solar minimum: lift-off, inner heliosphere, and in situ (1 AU) signatures SO ANNALES GEOPHYSICAE LA English DT Article DE radio science; remote sensing; solar physics, astrophysics and astronomy; flares and mass ejections; space plasma physics; nonlinear phenomena ID II RADIO EMISSIONS; MAGNETIC CLOUDS; INTERPLANETARY SHOCKS; PROTON TEMPERATURE; WIND SPACECRAFT; JANUARY 1997; ENERGETIC PARTICLES; LASCO OBSERVATIONS; SOURCE LOCATION; DRIVEN SHOCKS AB The extreme ultraviolet (EUV) signatures of a solar lift-off, decametric and kilometric radio burst emissions and energetic particle (EP) inner heliospheric signatures of an interplanetary shock, and in situ identification of its driver through solar wind observations are discussed for 12 isolated halo coronal mass ejections (H-CMEs) occurring between December 1996 and 1997. For the aforementioned twelve and the one event added in the discussion, it is found that ten passed several necessary conditions for being a "Sun-Earth connection". It is found that low corona EUV and Halpha chromospheric signatures indicate filament eruption as the cause of H-CME. These signatures indicate that the 12 events can be divided into two major subsets, 7 related to active regions (ARs) and 5 unrelated or related to decayed AR. In the case of events related to AR, there is indication of a faster liftoff, while a more gradual lift-off appears to characterize the second set. Inner heliospheric signatures - the presence of long lasting enhanced energetic particle flux and/or kilometric type II radio bursts - of a driven shock were identified in half of the 12 events. The in situ (1 AU) analyses using five different solar wind ejecta. signatures and comparisons with the bidirectional flow of suprathermal particles and For-bush decreases result in indications of a strong solar wind ejecta signatures for 11 out of 12 cases. From the discussion of these results, combined with work by other authors for overlapping events, we conclude that good Sun-Earth connection candidates originate most likely from solar filament eruptions with at least one of its extremities located closer to the central meridian than similar to30degreesE or similar to35degreesW with a larger extension in latitudinal location possible. In seven of the twelve cases it appears that the encountered ejecta was driving a shock at 1 AU. Support for this interpretation is found on the approximately equal velocity of the shock and the ejecta leading-edge. These shocks were weak to moderate in strength, and a comparison of their transit time with their local speed indicated a deceleration. In contradistinction with this result on shocks, the transit time versus the local speed of the ejecta appeared either to indicate that the ejecta as a whole traveled at constant speed or underwent a small amount of acceleration. This is a result that stands for cases with and without fast stream observations at their rear end. Seven out of twelve ejecta candidate intervals were themselves interplanetary magnetic cloud (IMC) or contained a previously identified IMC. As a by-product of this study, we noticed two good ejecta candidates at 1 AU for which observation of a H-CME or CME appears to be missing. C1 Emergent Informat Technol E, Largo, MD 20774 USA. Univ New Hampshire, Ctr Space Sci, Durham, NH 03824 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. MIT, Ctr Space Res, Cambridge, MA 02139 USA. USN, Res Lab, USRA, Washington, DC USA. USN, Res Lab, Washington, DC 20375 USA. RP Emergent Informat Technol E, Largo, MD 20774 USA. EM xrdbb@lepvx3.gsfc.nasa.gov RI Thompson, Barbara/C-9429-2012 NR 89 TC 36 Z9 36 U1 0 U2 0 PU COPERNICUS GESELLSCHAFT MBH PI GOTTINGEN PA BAHNHOFSALLEE 1E, GOTTINGEN, 37081, GERMANY SN 0992-7689 EI 1432-0576 J9 ANN GEOPHYS-GERMANY JI Ann. Geophys. PD JUL PY 2002 VL 20 IS 7 BP 891 EP 916 PG 26 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA 583HW UT WOS:000177402900003 ER PT J AU McKenna-Lawlor, SMP Dryer, M Smith, Z Kecskemety, K Fry, CD Sun, W Deehr, CS Berdichevsky, D Kudela, K Zastenker, G AF McKenna-Lawlor, SMP Dryer, M Smith, Z Kecskemety, K Fry, CD Sun, W Deehr, CS Berdichevsky, D Kudela, K Zastenker, G TI Arrival times of Flare/Halo CME associated shocks at the Earth: comparison of the predictions of three numerical models with these observations SO ANNALES GEOPHYSICAE LA English DT Article DE interplanetary physics; energetic particles; interplanetary shocks; solar wind plasma ID CORONAL MASS EJECTIONS; SOLAR ENERGETIC PARTICLES; INTERPLANETARY SHOCKS; GEOMAGNETIC STORM; WIND SPACECRAFT; FLARES; ACCELERATION; EVOLUTION; EVENTS; WAVES AB The arrival times at L1 of eleven travelling shocks associated both with X-ray flaring and with halo CMEs recorded aboard SOHO/LASCO have been considered. Close to the Sun the velocities of these events were estimated using either Type II radio records or CME speeds. Close to the Earth the shocks were detected in the data of various solar wind plasma, interplanetary magnetic field (IMF) and energetic particle experiments aboard SOHO, ACE, WIND, INTERBALL-1 and IMP-8. The real-time shock arrival predictions of three numerical models, namely the Shock Time of Arrival Model (STOA), the Interplanetary Shock Propagation Model (ISPM) and the Hakamada-Akasofu-Fry Solar Wind Model (HAFv.2) were tested against these observations. This is the first time that energetic protons (tens of keV to a few MeV) have been used to complement plasma and IMF data in validating shock propagation models. The models were all generally successful in predicting shock arrivals. STOA provided the smallest values of the "predicted minus measured" arrival times and displayed a typical predictive precision better than about 8 h. The ratio of the calculated standard deviation of the transit times to Earth to the standard deviation of the measurements was estimated for each model (treating interacting events as composite shocks) and these ratios turned out to be 0.60, 1.15 and 1.02 for STOA, ISPM and HAFv.2, respectively. If an event in the sample for which the shock velocity was not well known is omitted from consideration, these ratios become 0.36, 0.76 and 0.81, respectively. Larger statistical samples should now be tested. The ratio of the in situ shock velocity and the "Sun to L1" transit velocity (V-sh/V-tr) was in the range of 0.7-0.9 for individual, non-interacting, shock events. HAFv.2 uniquely provided information on those changes in the COBpoint (the moving Connection point on the shock along the IMF to the OBserver) which directly influenced energetic particle rise times. This model also illustrated the non-uniform upstream conditions through which the various shocks propagated; furthermore it simulated shock deformation on a scale of fractions of an AU. On the spatial scale (300 RE), where near-Earth spacecraft are located, the passing shocks, in conformity with the models, were found to be locally planar. ne shocks also showed tilting relative to the Sun-Earth line, probably reflecting the inherent directionality associated with their solar origin. C1 Natl Univ Ireland, Space Technol Ireland, Maynooth, Kildare, Ireland. Explorat Phys Int Inc, Milford, NH 03055 USA. NOAA, Space Environm Ctr, Boulder, CO 80305 USA. KFKI, Res Inst Particle & Nucl Phys, Budapest, Hungary. Univ Alaska, Inst Geophys, Fairbanks, AK 99775 USA. Emergent Informat Technol Inc, Largo, MD 20774 USA. NASA, GSFC, Extraterr Phys Lab, Greenbelt, MD 20771 USA. Inst Expt Phys, Kosice, Slovakia. Moscow Space Res Inst, Moscow 117997, Russia. RP McKenna-Lawlor, SMP (reprint author), Natl Univ Ireland, Space Technol Ireland, Maynooth, Kildare, Ireland. RI xue, yansheng/A-9712-2012 NR 69 TC 30 Z9 33 U1 0 U2 0 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 JUL PY 2002 VL 20 IS 7 BP 917 EP 935 PG 19 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA 583HW UT WOS:000177402900004 ER PT J AU Moretto, T Olsen, N Ritter, P Lu, G AF Moretto, T Olsen, N Ritter, P Lu, G TI Investigating the auroral electrojets with low altitude polar orbiting satellites SO ANNALES GEOPHYSICAE LA English DT Article DE ionosphere; electric fields and currents; magnetospheric physics; current systems; magnetosphere-ionosphere interactions ID INTERPLANETARY MAGNETIC-FIELD; IONOSPHERIC CURRENTS; ELECTRIC-FIELDS; CONVECTION; INDEXES; MODEL AB Three geomagnetic satellite missions currently provide high precision magnetic field measurements from low altitude polar orbiting spacecraft. We demonstrate how these data can be used to determine the intensity and location of the horizontal currents that flow in the ionosphere, predominantly in the auroral electrojets. First, we examine the results during a recent geomagnetic storm. The currents derived from two satellites at different altitudes are in very good agreement, which verifies good stability of the method. Further, a very high degree of correlation (correlation coefficients of 0.8-0.9) is observed between the amplitudes of the derived currents and the commonly used auroral electro-jet indices based on magnetic measurements at ground. This points to the potential of defining an auroral activity index based on the satellite observations, which could be useful for space weather monitoring. A specific advantage of the satellite observations over the ground-based magnetic measurements is their coverage of the Southern Hemisphere, as well as the Northern. We utilize this in an investigation of the ionospheric currents observed in both polar regions during a period of unusually steady interplanetary magnetic field with a large negative Y-component. A pronounced asymmetry is found between the currents in the two hemispheres, which indicates real inter-hemispheric differences beyond the mirror-asymmetry between hemispheres that earlier studies have revealed. The method is also applied to another event for which the combined measurements of the three satellites provide a comprehensive view of the current systems. The analysis hereof reveals some surprising results concerning the connection between solar wind driver and the resulting ionospheric currents. Specifically, preconditioning of the magnetosphere (history of the interplanetary magnetic field) is seen to play an important role, and in the winter hemisphere, it seems to be harder to drive currents on the nightside than on the dayside. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. Danish Space Res Inst, Copenhagen, Denmark. Geoforsch Zentrum Potsdam, Potsdam, Germany. High Altitude Observ, Boulder, CO USA. RP Moretto, T (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. RI Lu, Gang/A-6669-2011; Olsen, Nils/H-1822-2011; Moretto, Therese/B-6846-2013; Ritter, Patricia/D-7411-2013 OI Olsen, Nils/0000-0003-1132-6113; Moretto, Therese/0000-0002-2403-5561; Ritter, Patricia/0000-0002-0926-1771 NR 32 TC 12 Z9 12 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 JUL PY 2002 VL 20 IS 7 BP 1049 EP 1061 PG 13 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA 583HW UT WOS:000177402900016 ER PT J AU Gallagher, PT Denker, C Yurchyshyn, V Spirock, T Qiu, J Wang, H Goode, PR AF Gallagher, PT Denker, C Yurchyshyn, V Spirock, T Qiu, J Wang, H Goode, PR TI Solar activity monitoring and forecasting capabilities at Big Bear Solar Observatory SO ANNALES GEOPHYSICAE LA English DT Article DE solar physics, astronomy and astrophysics; flares and mass ejections; instruments and techniques; photosphere and chromosphere ID MICHELSON DOPPLER IMAGER; VECTOR MAGNETIC-FIELD; FLARE; REGION; EVOLUTION; MAGNETOGRAMS; TELESCOPE; SUNSPOTS; MISSION; SYSTEM AB The availability of full-disk, high-resolution Ha images from Big Bear Solar Observatory (USA), Kanzelhohe Solar Observatory (Austria), and Yunnan Astronomical Observatory (China) allows for the continual monitoring of solar activity with unprecedented spatial and temporal resolution. Typically, this Global Ha Network (GHN) provides almost uninterrupted Ha images with a cadence of 1 min and an imaoe scale of 1" per pixel. Every hour, GHN images are transferred to the web-based BBSO Active Region Monitor (ARM; www.bbso.njit.edu/arm), which includes the most recent EUV, continuum, and magnetogram data from the Solar and Heliospheric Observatory, together with magnetograms from the Global Oscillation Network Group. ARM also includes a variety of active region properties from the National Oceanic and Atmospheric Administration's Space Environment Center, such as up-to-date active region positions, GOES 5-min X-ray data, and flare identification. Stokes I, V, Q, and U images are available from the recently operational BBSO Digital Vector Magnetograph and the Vector Magnetograph at the Huairou Solar Observing Station of Beijing Observatory. Vector magnetograms provide complete information on the photospheric magnetic field, and allow for magnetic flux gradients, electric currents, and shear forces to be calculated: these measurements are extremely sensitive to conditions resulting in flaring activity. Furthermore, we have developed a Flare Prediction System which estimates the probability for each region to produce C-, M-, or X-class flares based on nearly eight years of NOAA data from cycle 22. This, in addition to BBSO's daily solar activity reports, has proven a useful resource for activity forecasting. C1 NASA, Goddard Space Flight Ctr, Com Analyt Corp L3, Greenbelt, MD 20771 USA. New Jersey Inst Technol, Big Bear Solar Observ, Big Bear City, CA 92314 USA. RP Gallagher, PT (reprint author), NASA, Goddard Space Flight Ctr, Com Analyt Corp L3, Greenbelt, MD 20771 USA. RI Gallagher, Peter/C-7717-2011 OI Gallagher, Peter/0000-0001-9745-0400 NR 36 TC 6 Z9 6 U1 1 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 JUL PY 2002 VL 20 IS 7 BP 1105 EP 1115 PG 11 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA 583HW UT WOS:000177402900020 ER PT J AU Moller, KD Sternberg, O Grebel, H Stewart, KP AF Moller, KD Sternberg, O Grebel, H Stewart, KP TI Inductive cross-shaped metal meshes and dielectrics SO APPLIED OPTICS LA English DT Article ID BANDPASS-FILTERS; BOUNDARY; THIN AB The Micro-Stripes program has been used to calculate resonance wavelengths and the bandwidth of inductive cross-shaped metal meshes in contact with dielectric layers. The shift of the resonance wavelength, depending on the thickness of the dielectric layers, has been studied for two refractive indices. The transmittance of two mesh filters with dielectric spacers or embedded in a dielectric has been calculated for specific alignment of the crosses of one mesh with respect to the other. Transmission line theory has been used to calculate the transmittance of two mesh filters with nonaligned crosses and dielectric layers. A coupled oscillator model has been used for interpretation of the interaction of resonance and Fabry-Perot modes. (C) 2002 Optical Society of America. C1 New Jersey Inst Technol, Dept Phys, Newark, NJ 07102 USA. New Jersey Inst Technol, Electron Imaging Ctr, Newark, NJ 07102 USA. New Jersey Inst Technol, Elect Imaging Ctr, Newark, NJ 07102 USA. Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Moller, KD (reprint author), New Jersey Inst Technol, Dept Phys, Newark, NJ 07102 USA. EM kdmoel927@aol.com NR 17 TC 7 Z9 7 U1 0 U2 2 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD JUL 1 PY 2002 VL 41 IS 19 BP 3919 EP 3926 DI 10.1364/AO.41.003919 PG 8 WC Optics SC Optics GA 570RR UT WOS:000176671900020 PM 12099601 ER PT J AU Dong, WJ Carter, GA Barber, JT AF Dong, WJ Carter, GA Barber, JT TI Spectral reflectance of Lemna gibba fronds exposed to ethylene glycol SO AQUATIC BOTANY LA English DT Article DE duckweed; ethylene glycol; Lemna gibba; reflectance; spectrum ID LEAF OPTICAL-PROPERTIES; TOXICITY AB Spectroradiometry was used to quantify changes in duckweed frond reflectance that occurred throughout the 400-850 nm spectrum under various ethylene glycol (EG) concentrations and exposure times. The threshold concentration of EG at which a reflectance change could be detected was between 35 and 40 mM (P less than or equal to 0.01), approximately, the same as by visual observation. EG-induced changes in frond reflectance were maximal at concentrations of 50 mM or greater. Reflectance changes were detectable within 24 h of exposure to 100 mM EG, 2-3 days prior to changes in frond appearance. Thus, spectroradiometry of duckweed may serve as a rapid and sensitive technique for detection of ecosystem exposure to EG and perhaps other stress agents. Published by Elsevier Science B.V. C1 NASA, Earth Sci Applicat Directorate, Stennis Space Ctr, MS 39529 USA. Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. Tulane Univ, Dept Ecol & Evolutionary Biol, New Orleans, LA 70118 USA. RP Carter, GA (reprint author), NASA, Earth Sci Applicat Directorate, Stennis Space Ctr, MS 39529 USA. NR 19 TC 0 Z9 0 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-3770 J9 AQUAT BOT JI Aquat. Bot. PD JUL PY 2002 VL 73 IS 3 BP 275 EP 281 AR PII S0304-3770(02)00026-8 DI 10.1016/S0304-3770(02)00026-8 PG 7 WC Plant Sciences; Marine & Freshwater Biology SC Plant Sciences; Marine & Freshwater Biology GA 578NP UT WOS:000177124800008 ER PT J AU Holden, BP Stanford, SA Squires, GK Rosati, P Tozzi, P Eisenhardt, P AF Holden, BP Stanford, SA Squires, GK Rosati, P Tozzi, P Eisenhardt, P TI Moderate-temperature clusters of galaxies from the RDCS and the high-redshift luminosity-temperature relation SO ASTRONOMICAL JOURNAL LA English DT Article DE catalogs; cosmology : observations; galaxies : clusters : general; galaxies : clusters : individual (RDCS 1350+6007, RDCS 1317+2911, CXOU J0910.1+5419, CXOU J1316.9+2914); X-rays ID HUBBLE DEEP FIELD; X-RAY LUMINOSITY; INTERGALACTIC GAS; SCALING RELATIONS; DISTANT CLUSTERS; DARK-MATTER; EVOLUTION; DEPROJECTION; ENTROPY; CHANDRA AB We present our discovery observations and analysis of RDCS 1317+ 2911, z = 0.805, and RDCS 1350+6007, z = 0.804, two clusters of galaxies identified through X-ray emission in the ROSAT Deep Cluster Survey ( RDCS). RDCS 1317+ 2911 has an unusual morphology in our Chandra observations, with an asymmetric surface brightness pro le and a bend in the distribution of X-ray emission. In contrast, RDCS 1350+6007 appears to be more like low-redshift clusters, with beta = 0.49 +/- 0.06 and r(core) = 165 +/- 5 kpc (Omega(m) = 0.3, Omega(Lambda) = 0.7, H-0 = 65 km s(-1) Mpc(-1)), though it also has an elliptical, slightly asymmetric surface brightness profile. Wefind a temperature of 3.7(-0.9)(+1.5) keV and a bolometric luminosity of 8.2(-1.6)(+1.5) x 10(43) ergs s(-1) for RDCS 1317+ 2911, and a temperature of 4.9(-0.9)(+1.5) keV and a bolometric luminosity of 4.1(-0.4)(+0.5)x 10(44) ergs s(-1) for RDCS 1350+6007. Our weak-lensing analysis of RDCS 1350+6007 confirms the general shape of the inner density pro le but predicts twice the mass of the model based on the X-ray pro le. There are two possibilities for this discrepancy: either there is a significant amount of mass near the redshift of the cluster that has not yet fallen into the potential well and shock-heated the gas, or, as we only see the X-ray emission from the core of the cluster, our model fails to describe the true shape of the underlying potential. We combine the X-ray luminosities and temperatures for RDCS clusters of galaxies with such measurements of other clusters at high redshift ( z > 0.7) and fit the luminosity-temperature relation. We find no statistically significant evolution in the slope or zero point of this relation at z(median) = 0.83. This result is in agreement with models of intracluster medium evolution with significant preheating or high initial entropy values. Quantifying the bolometric luminosity-temperature relation as L = L-6 (1 + z)(A) ( T/6 keV)(alpha), we find alpha = 2.9 +/- 0.4, L-6 = 8.7 +/- 0.9 x 10(44) ergs s(-1) and A = 0.3 +/- 0.2, or A = 0.4 +/- 0.2, depending on which low-redshift luminosity-temperature relation we compare with. With this result, we rule out at the 5 level the self-similar scaling model of intracluster medium evolution. We discuss how low-temperature, high-redshift clusters of galaxies will allow us to improve on this result, and we announce the discovery of two such objects, CXOU J0910.1+5419 and CXOU J1316.9+2914. C1 CALTECH, SIRTF Sci Ctr, Pasadena, CA 91125 USA. European So Observ, D-85748 Garching, Germany. Osserv Astron Trieste, I-34131 Trieste, Italy. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. RP Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. EM bholden@igpp.ucllnl.org; adam@igpp.ucllnl.org; squires@ipac.caltech.edu; prosati@eso.org; tozzi@ts.astro.it; prme@kromos.jpl.nasa.gov NR 72 TC 43 Z9 43 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 JUL PY 2002 VL 124 IS 1 BP 33 EP 45 DI 10.1086/340966 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 563UA UT WOS:000176272900003 ER PT J AU Doi, T O'Dell, CR Hartigan, P AF Doi, T O'Dell, CR Hartigan, P TI Internal velocities in the Orion Nebula: Large proper-motion features SO ASTRONOMICAL JOURNAL LA English DT Article DE Herbig-Haro objects; ISM : individual (Orion Nebula); ISM : jets and outflows; stars : winds, outflows ID HUBBLE-SPACE-TELESCOPE; HERBIG-HARO OBJECTS; ADAPTIVE OPTICS; IMAGES; OMC-1; SPECTROSCOPY; OUTFLOWS; M42; CIRCUMSTELLAR; RESOLUTION AB The proper motions of Herbig-Haro (HH) objects in the Orion Nebula were measured with a +/-10 km s(-1) accuracy using the Hubble Space Telescope Wide Field Planetary Camera 2 images in [S II], [N II], Halpha, and [O III], taken 4-6 yr apart. Seven HH flows in the outer region as well as seven HH objects in the inner region of the BN-KL complex were identified. The H-2 finger system was confirmed to be created by an explosive event that took place approximately 1000 yr ago. We found a new HH flow toward the northwest originating from the vicinity of OMC-1S, which may be a part of the low-velocity bipolar flows centered at FIR 4. The proper motion of HH 202 was also measured with high accuracy for the first time. The proper-motion vectors of HH 202 and HH 203/204 are aligned well with their projected symmetric axis, which may indicate that they emanated from the same source. The proper-motion measurements in various emission lines provide generally the same results in the wide range of velocity from 20 to 400 km s(-1), as expected for shocks in a steady state. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Vanderbilt Univ, Dept Phys & Astron, Nashville, TN 37235 USA. Rice Univ, Dept Phys & Astron, Houston, TX 77005 USA. RP Doi, T (reprint author), NASA, Lyndon B Johnson Space Ctr, 2101 NASA Rd 1, Houston, TX 77058 USA. NR 45 TC 49 Z9 49 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD JUL PY 2002 VL 124 IS 1 BP 445 EP 463 DI 10.1086/341044 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 563UA UT WOS:000176272900029 ER PT J AU Rebull, LM Wolff, SC Strom, SE Makidon, RB AF Rebull, LM Wolff, SC Strom, SE Makidon, RB TI The early angular momentum history of low-mass stars: Evidence for a regulation mechanism SO ASTRONOMICAL JOURNAL LA English DT Article DE stars : pre-main-sequence; stars : rotation ID ORION-NEBULA-CLUSTER; MAIN-SEQUENCE TRACKS; T-TAURI STARS; ROTATION PERIODS; DISK ACCRETION; EVOLUTION; PROTOSTARS; NGC-2264 AB We examine the early angular momentum history of stars in young clusters via 197 photometric periods in fields flanking the Orion Nebula cluster (ONC), 81 photometric periods in NGC 2264, and 202 measurements of v sin i in the ONC itself. We show that pre-main-sequence stars spanning an age range from 0.1 to 3 Myr do not appear to conserve stellar angular momentum as they evolve down their convective tracks, but instead preserve the same range of periods even though they have contracted by about a factor of 3. This result seems to require a mechanism that regulates the angular velocities of young stars. We discuss several candidate mechanisms. The most plausible appears to be disk locking, though most of our stars do not have I-C-K-s excesses suggestive of disks. However, a decisive test of this hypothesis requires a more sensitive diagnostic than the I-C-K-s excesses used here. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Natl Opt Astron Observ, Tucson, AZ USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. RP Rebull, LM (reprint author), CALTECH, SIRTF Sci Ctr, Mail Stop 220-6,1200 E Calif Blvd, Pasadena, CA 91125 USA. OI Rebull, Luisa/0000-0001-6381-515X NR 43 TC 33 Z9 33 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD JUL PY 2002 VL 124 IS 1 BP 546 EP 559 DI 10.1086/340806 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 563UA UT WOS:000176272900037 ER PT J AU Laughlin, G Chambers, JE AF Laughlin, G Chambers, JE TI Extrasolar Trojans: The viability and detectability of planets in the 1 : 1 resonance SO ASTRONOMICAL JOURNAL LA English DT Article DE planetary systems : general ID VORTICES; ANDROMEDAE; ORBITS; GJ-876; DISKS; PAIR AB We explore the possibility that extrasolar planets might be found in the 1 : 1 mean motion resonance, in which a pair of planets share a time-averaged orbital period. There are a variety of stable co-orbital configurations, and we specifically examine three different versions of the 1 : 1 resonance. In the first configuration, the two planets and the star participate in tadpole-type librations about the vertices of an equilateral triangle. The dynamics of this situation resemble the orbits of Jupiter's Trojan asteroids. We show analytically that an equilateral configuration consisting of a star and two equal-mass planets is linearly stable for mass ratios mu = 2m(pl)/(2m(pl) + M-*) < 0.03812. When the equilateral configuration is subjected to larger perturbations, a related 1 : 1 resonance occurs. In this second family of configurations, the planet pair executes horseshoe-type orbits in which the librating motion in the corotating frame is symmetric about a 180 separation. The Saturnian satellites Janus and Epimetheus provide a solar system example of this phenomenon. In the case of equal-mass planets, a numerical survey indicates that horseshoe configurations are stable over long periods for mass ratios μ < 0.0004, indicating that a pair of Saturn-mass planets can exist in this resonance. The third configuration that we examine is more exotic and involves a pair of planets that exchange angular momentum in a manner that allows them to indefinitely avoid close encounters. An illustrative example of this resonance occurs when one planet has a highly eccentric orbit while the other planet moves on a nearly circular orbit; the periapses are in alignment, and conjunctions occur near periapse. All three of these resonant configurations can be stable over timescales comparable to or longer than stellar lifetimes. We show that pairs of planets in 1 : 1 resonance yield characteristic radial velocity signatures that are not prone to the sin i degeneracy. Indeed, Keplerian fits to the radial velocities cannot reveal the presence of two planets in the 1 : 1 resonance. We discuss a dynamical fitting method for such systems and illustrate its use with a simulated data set. Finally, we argue that hydrodynamic simulations and torqued three-body simulations indicate that 1 : 1 resonant pairs might readily form and migrate within protostellar disks. C1 Univ Calif Santa Cruz, Univ Calif Observ, Lick Observ, Santa Cruz, CA 95064 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Laughlin, G (reprint author), Univ Calif Santa Cruz, Univ Calif Observ, Lick Observ, Santa Cruz, CA 95064 USA. NR 24 TC 76 Z9 76 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD JUL PY 2002 VL 124 IS 1 BP 592 EP 600 DI 10.1086/341173 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 563UA UT WOS:000176272900042 ER PT J AU Van Winckel, H Cohen, M Gull, TR AF Van Winckel, H Cohen, M Gull, TR TI The ERE of the "Red Rectangle" revisited SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars : post-AGB stars; stars : circumstellar matter; stars : individual : Red Rectangle; ISM : molecules ID DIFFUSE INTERSTELLAR BAND; MOLECULAR-EMISSION BANDS; SILICON NANOPARTICLES; HD-44179; ULTRAVIOLET; BINARY; NEBULA; SPECTRUM; CARRIER; SYSTEM AB We present in this paper high signal-to-noise long-slit optical spectra of the Extended Red Emission (ERE) in the "Red Rectangle" (RR) nebula. These spectra, obtained at different positions in the nebula, reveal an extremely complex emission pattern on top of the broad ERE continuum. It is well known that three features converge at large distance from the central object, in wavelength and profile to the diffuse interstellar bands (DIBs) at lambda5797, lambda5849.8, and lambda6614 Angstrom (e.g. Sarre et al. 1995). In this paper we give a detailed inventory of all spectral subfeatures observed in the 5550-6850 Angstrom spectral range. Thanks to our high S/N spectra, we propose 5 new features in the RR that can be associated with DIBs. For the 5550-6200 Angstrom spectral range our slit position was on top of the NE spike of the X shaped nebula. A detailed description of the spatial profile-changes is given of the strongest features revealing that even far out in the nebula at 2400 from the central star, there remains a small shift in wavelength of 1 respectively 2 Angstrom between the ERE subfeatures and the DIB wavelengths of lambda5797.11 and lambda5849.78 Angstrom. C1 Katholieke Univ Leuven, Inst Sterrenkunde, B-3000 Louvain, Belgium. Univ Calif Berkeley, Radio Astron Lab, Berkeley, CA 94720 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Van Winckel, H (reprint author), Katholieke Univ Leuven, Inst Sterrenkunde, Celestijnenlaan 200B, B-3000 Louvain, Belgium. RI Gull, Theodore/D-2753-2012; Van Winckel, Hans/I-7863-2013 OI Gull, Theodore/0000-0002-6851-5380; Van Winckel, Hans/0000-0001-5158-9327 NR 36 TC 30 Z9 30 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 JUL PY 2002 VL 390 IS 1 BP 147 EP 154 DI 10.1051/0004-6361:20020623 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 576AE UT WOS:000176980000018 ER PT J AU Bujarrabal, V Alcolea, J Contreras, CS Sahai, R AF Bujarrabal, V Alcolea, J Contreras, CS Sahai, R TI HST observations of the protoplanetary nebula OH 231.8+4.2: The structure of the jets and shocks SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars : AGB and post-AGB; stars : circumstellar matter; radio-lines : stars; planetary nebulae : individual : OH 231.8+4.2 ID YOUNG STELLAR OBJECTS; NUMERICAL SIMULATIONS; OUTFLOW COLLIMATION; PROTOSTELLAR JETS; BIPOLAR OUTFLOW; BOW SHOCK; OH-231.8+4.2; MODELS; OH231.8+4.2; STAR AB We present high-resolution images obtained with the WFPC2, on board the HST, of the protoplanetary nebula (PPN) OH231.8+4.2. Halpha and NII line emission and scattered light in the continuum at 6750 and 7910 Angstrom were observed. We also discuss NIR NICMOS images from the HST archive. The images show with high accuracy the shape and excitation state of the shocks developed in the nebula. Our high-resolution images (and data from other works) allow a very detailed and quantitative description of the different nebular components and of the physical conditions in them. We interpret specific structures identified in our images using existing models of shock interaction. In the center of the nebula, there is a dense torus- or disk-like condensation continued by an hourglass-like structure, with relatively high densities (similar to10(5) -10(6) cm(-3)) and temperatures (similar to30 K). Inside this torus we have identified the location of the central star, from SiO maser observations. Two shock regions are detected from the optical line emission images, respectively in the north and south lobes. In both regions, a forward and a backward shock are identified. The densities of this hot gas vary between 40 and 250 cm(-3), with the densest clumps being placed in the reverse shocks. The total mass of the shocked hot gas is similar to2 x 10(-3) M., both lobes showing similar masses in spite of their different extents. The relatively collimated jet that impinges on an originally slow shell, so producing the shocks, is identified from the scattered light images and in CO maps. This flow is significantly denser and cooler than the shocked Halpha regions. Its density decreases with the distance to the star, with typical values (similar to10(5)-10(4) cm(-3)), and its temperature ranges between about 25 and 8 K. We explain the high Halpha emission of the backward shock assuming that it propagates in a diffuse gas component, entrained by the observed collimated flow and sharing its axial movement. The existence of shocks also in the collimated densest flow is suggested by the high abundance of some molecules like HCO+ and its structure and kinematics in certain regions, but they are not seen in Halpha emission, probably because of the absence of (well developed) hot components in this dense flow. We think that the exceptionally detailed and quantitative image derived for the wind interaction regions in OH231.8+4.2 is a challenge to check and improve hydrodynamical models of wind interaction in PPNe. C1 Observ Astron Nacl, Alcala De Henares 28800, Spain. Observ Astron Nacl, Madrid 28014, Spain. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bujarrabal, V (reprint author), Observ Astron Nacl, Apartado 1143, Alcala De Henares 28800, Spain. RI Sanchez-Contreras, Carmen/N-3718-2015 OI Sanchez-Contreras, Carmen/0000-0002-6341-592X NR 23 TC 39 Z9 39 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 JUL PY 2002 VL 389 IS 1 BP 271 EP 285 DI 10.1051/0004-6361:20020455 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 568UA UT WOS:000176561500032 ER PT J AU Tuthill, PG Men'shchikov, AB Schertl, D Monnier, JD Danchi, WC Weigelt, G AF Tuthill, PG Men'shchikov, AB Schertl, D Monnier, JD Danchi, WC Weigelt, G TI Bispectrum speckle interferometry of the Red Rectangle: Diffraction-limited near-infrared images reconstructed from Keck telescope speckle data SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE techniques : image processing; circumstellar matter; stars : individual : Red Rectangle; stars : mass-loss; stars : AGB and post-AGB; infrared : stars ID RESOLUTION; EVOLUTION; EMISSION; MASKING; NEBULAE AB We present new near-infrared (2.1-3.3 mum) images of the Red Rectangle with unprecedented diffraction-limited angular resolutions of 46-68 mas; 4 times higher than that of the Hubble space telescope and almost a factor of two improvement over the previous 6 m SAO telecope speckle images presented by Men'shchikov et al. (1998). The new images, which were reconstructed from Keck telescope speckle data using the bispectrum speckle interferometry method, clearly show two bright lobes above and below the optically thick dark lane obscuring the central binary. X-shaped spikes, thought to trace the surface of a biconical flow, change the intensity distribution of the bright lobes, making them appear broadened or with an east-west double-peak in images with the highest resolution. The striking biconical appearance of the Red Rectangle is preserved on scales from 50 mas to 10 and from the visible (red) to at least 10 mum, implying that large grains of at least several microns in size dominate scattering. The new images supplement previous 76 mas resolution speckle reconstructions at shorter wavelengths of 0.6-0.8 mum (Osterbart et al. 1997) and 0.7-2.2 mum (Men'shchikov et al. 1998), allowing a more detailed analysis of the famous bipolar nebula. The intensity distribution of the images is inconsistent with a at disk geometry frequently used to model the bipolar nebulae. Instead, a geometrically thick torus-like density distribution with bipolar conical cavities is preferred. The extent of the bright lobes indicates that the dense torus has a diameter of greater than or similar to 100 AU, for an assumed distance of 330 pc. This torus may be the outer reaches of a flared thick disk tapering inwards to the central star, however such a density enhancement on the midplane is not strictly required to explain the narrow dark lane obscuring the central stars. C1 Univ Sydney, Sch Phys, Dept Astron, Sydney, NSW 2006, Australia. Max Planck Inst Radioastron, D-53121 Bonn, Germany. Smithsonian Astrophys Observ MS 42, Cambridge, MA 02138 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Tuthill, PG (reprint author), Univ Sydney, Sch Phys, Dept Astron, Sydney, NSW 2006, Australia. NR 19 TC 26 Z9 27 U1 0 U2 2 PU E D P SCIENCES PI LES ULIS CEDEXA PA 7, AVE DU HOGGAR, PARC D ACTIVITES COURTABOEUF, BP 112, F-91944 LES ULIS CEDEXA, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JUL PY 2002 VL 389 IS 3 BP 889 EP 895 DI 10.1051/0004-6361:20020292 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 574FL UT WOS:000176877800019 ER PT J AU Hellier, C Beardmore, AP Mukai, K AF Hellier, C Beardmore, AP Mukai, K TI The spin pulse of the intermediate polar V1062 Tauri SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE accretion, accretion disks; stars : individual : V1062 Tau; novae, cataclysmic variables; binaries : close; X-rays : stars ID X-RAY OBSERVATIONS; MAGNETIC CATACLYSMIC VARIABLES; LIGHT CURVES; AO PISCIUM; SPECTRUM AB We combine ASCA and RXTE data of V1062 Tau to confirm the presence of a 62-min X-ray pulsation. We show that the pulsation is caused largely by the variation of dense partial absorption, in keeping with current models of accretion onto magnetic white dwarfs. Further parametrisation of the spin pulse is, however, hampered by ambiguities in the models. C1 Univ Keele, Sch Chem & Phys, Astrophys Grp, Keele ST5 5BG, Staffs, England. NASA, Goddard Space Flight Ctr, High Energy Phys Lab, Greenbelt, MD 20771 USA. RP Hellier, C (reprint author), Univ Keele, Sch Chem & Phys, Astrophys Grp, Keele ST5 5BG, Staffs, England. NR 19 TC 9 Z9 9 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 JUL PY 2002 VL 389 IS 3 BP 904 EP 907 DI 10.1051/0004-6361:20020634 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 574FL UT WOS:000176877800021 ER PT J AU in't Zand, JJM Verbunt, F Kuulkers, E Markwardt, CB Bazzano, A Cocchi, M Cornelisse, R Heise, J Natalucci, L Ubertini, P AF in't Zand, JJM Verbunt, F Kuulkers, E Markwardt, CB Bazzano, A Cocchi, M Cornelisse, R Heise, J Natalucci, L Ubertini, P TI Discovery of the neutron star nature of SLX 1737-282 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE accretion, accretion disks; binaries : close; X-rays : stars : individual : SLX 1737-282, 2E 1737.5-2817, 1RXS J174043.1-281806, RX J1740.7-2818, AX J1740.7-2818 ID RAY ASTRONOMY SATELLITE; GALACTIC-CENTER; ON-BOARD; CATALOG; ONBOARD; BURSTS; IMAGES AB SLX 1737-282 is a persistent moderately bright X-ray source 1.degrees2 from the Galactic center. X-ray observations with the Wide Field Cameras on BeppoSAX have for the first time revealed the true nature of SLX 1737-282: a 15 min long thermonuclear ash was detected exposing the source as a neutron star in a binary system. The ash was Eddington-limited constraining the distance to between 5 and 8 kpc. We analyze BeppoSAX, ROSAT, and RXTE data on SLX 1737-282. The persistent 0.5-200 keV luminosity is close to or less than 1% of the Eddington limit which implies a rarely-seen circumstance for thermonuclear ash activity. C1 Univ Utrecht, Astron Inst, NL-3508 TA Utrecht, Netherlands. SRON, Natl Inst Space Res, NL-3584 CA Utrecht, Netherlands. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. CNR, Ist Astrofis Spaziale & Fys Cosm, Area Ric Roma Tor Vergata, I-00133 Rome, Italy. RP in't Zand, JJM (reprint author), Univ Utrecht, Astron Inst, POB 80000, NL-3508 TA Utrecht, Netherlands. OI Bazzano, Angela/0000-0002-2017-4396 NR 26 TC 26 Z9 26 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 JUL PY 2002 VL 389 IS 2 BP L43 EP L46 DI 10.1051/0004-6361:20020631 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 573EW UT WOS:000176817200001 ER PT J AU Price, PA Berger, E Kulkarni, SR Djorgovski, SG Fox, DW Mahabal, A Hurley, K Bloom, JS Frail, DA Galama, TJ Harrison, FA Morrison, G Reichart, DE Yost, SA Sari, R Axelrod, TS Cline, T Golenetskii, S Mazets, E Schmidt, BP Trombka, J AF Price, PA Berger, E Kulkarni, SR Djorgovski, SG Fox, DW Mahabal, A Hurley, K Bloom, JS Frail, DA Galama, TJ Harrison, FA Morrison, G Reichart, DE Yost, SA Sari, R Axelrod, TS Cline, T Golenetskii, S Mazets, E Schmidt, BP Trombka, J TI The unusually long duration gamma-ray burst GRB 000911: Discovery of the afterglow and host galaxy SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : high-redshift; gamma rays : bursts ID 28 FEBRUARY 1997; RADIO AFTERGLOW; STAR-FORMATION; SUPERNOVA; EMISSION; SPECTRA; MODELS AB Of all the well-localized gamma-ray bursts, GRB 000911 has the longest duration (T-90 = 500 s) and ranks in the top 1% of BATSE bursts for fluence. Here we report the discovery of the afterglow of this unique burst. In order to simultaneously fit our radio and optical observations, we are required to invoke a model involving a hard electron distribution, p similar to 1.5, and a jet-break time less than 1.5 days. A spectrum of the host galaxy taken 111 days after the burst reveals a single emission line, interpreted as [O II] at a redshift z = 1.0585, and a continuum break that we interpret as the Balmer limit at this redshift. Despite the long T-90, the afterglow of GRB 000911 is not unusual in any other way when compared to the set of afterglows studied to date. We conclude that the duration of the GRB plays little part in determining the physics of the afterglow. C1 CALTECH, Palomar Observ, Pasadena, CA 91125 USA. Mt Stromlo & Siding Spring Observ, Res Sch Astron & Astrophys, Weston, ACT 2611, Australia. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Natl Radio Astron Observ, Socorro, NM 87801 USA. CALTECH, Ctr Infrared Proc & Anal, Pasadena, CA 91125 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. AF Ioffe Phys Tech Inst, St Petersburg 194021, Russia. RP Price, PA (reprint author), CALTECH, Palomar Observ, MS 105-24, Pasadena, CA 91125 USA. RI Galama, Titus/D-1429-2014; Golenetskii, Sergey/B-3818-2015; OI Galama, Titus/0000-0002-1036-396X; Schmidt, Brian/0000-0001-6589-1287 NR 41 TC 39 Z9 39 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 JUL 1 PY 2002 VL 573 IS 1 BP 85 EP 91 DI 10.1086/340585 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 564YD UT WOS:000176340400009 ER PT J AU Moffat, AFJ Corcoran, MF Stevens, IR Skalkowski, G Marchenko, SV Mucke, A Ptak, A Koribalski, BS Brenneman, L Mushotzky, R Pittard, JM Pollock, AMT Brandner, W AF Moffat, AFJ Corcoran, MF Stevens, IR Skalkowski, G Marchenko, SV Mucke, A Ptak, A Koribalski, BS Brenneman, L Mushotzky, R Pittard, JM Pollock, AMT Brandner, W TI Galactic starburst NGC 3603 from X-rays to radio SO ASTROPHYSICAL JOURNAL LA English DT Article DE open clusters and associations : individual (NGC 3603); stars : early-type; stars : winds, outflows ID H-II REGION; O-STARS; IMAGING SPECTROMETER; STELLAR CONTENT; GALAXY M82; NGC-3603; EMISSION; SPECTRA; CORE; HOT AB NGC 3603 is the most massive and luminous visible starburst region in the Galaxy. We present the first Chandra ACIS-I X-ray image and spectra of this dense, exotic object, accompanied by a deep centimeter-wavelength Australia Telescope Compact Array radio image at similar less than or similar to1" spatial resolution and Hubble Space Telescope/ground-based optical data. At the S/N > 3 level, Chandra detects several hundred X-ray point sources (compared to the three distinct sources seen by ROSAT). At least 40 of these sources are definitely associated with optically identified cluster O- and W-R type members, but most are not. A diffuse Xray component is also seen out to similar to2' (4 pc) from the center, probably arising mainly from the large number of merging/colliding hot stellar winds and/or numerous faint cluster sources. The point-source X-ray fluxes generally increase with increasing bolometric brightnesses of the member O/W-R stars, but with very large scatter. Some exceptionally bright stellar X-ray sources may be colliding wind binaries. The radio image shows (1) two resolved sources, one definitely nonthermal, in the cluster core near where the X-ray/optically brightest stars with the strongest stellar winds are located, (2) emission from all three known proplyd-like objects (with thermal and nonthermal components), and (3) many thermal sources in the peripheral regions of triggered star formation. Overall, NGC 3603 appears to be a somewhat younger and hotter scaled-down version of typical starbursts found in other galaxies. C1 Univ Montreal, Dept Phys, Montreal, PQ H3C 3J7, Canada. Univ Space Res Assoc, Lanham, MD 20706 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Univ Birmingham, Sch Phys & Astron, Birmingham B15 2TT, W Midlands, England. Carnegie Mellon Univ, Dept Phys, Pittsburgh, PA 15213 USA. CSIRO, Australia Telescope Natl Facil, Epping, NSW 1710, Australia. Univ Leeds, Dept Phys & Astron, Leeds LS2 9JT, W Yorkshire, England. Comp & Sci Co Ltd, Sheffield S10 3GS, S Yorkshire, England. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. RP Moffat, AFJ (reprint author), Univ Montreal, Dept Phys, CP 6128,Succ Ctr Ville, Montreal, PQ H3C 3J7, Canada. RI Koribalski, Baerbel/B-9987-2008; Ptak, Andrew/D-3574-2012; OI Pittard, Julian/0000-0003-2244-5070 NR 42 TC 71 Z9 71 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 1 PY 2002 VL 573 IS 1 BP 191 EP 198 DI 10.1086/340491 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 564YD UT WOS:000176340400020 ER PT J AU Gorti, U Hollenbach, D AF Gorti, U Hollenbach, D TI Photoevaporation of clumps in photodissociation regions SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : clouds; ISM : kinematics and dynamics; stars : early-type; stars : formation; ultraviolet : stars ID PHOTON-DOMINATED REGION; H-II REGIONS; MOLECULAR CLOUDS; ORION BAR; INTERSTELLAR CLOUDS; STAR-FORMATION; DENSE CORES; PHYSICAL CONDITIONS; LINE OBSERVATIONS; MAGNETIC-FIELDS AB We present the results of an investigation of the effects of far-ultraviolet (FUV) radiation (6.0 eV < h < 13.6 eV) from hot early-type OB stars on clumps in star-forming molecular clouds. Clumps in FUV-illuminated regions (or photodissociation regions [PDRs]) undergo external heating and photodissociation as they are exposed to the FUV field, resulting in a loss of cold, molecular clump mass as it is converted to warm atomic gas. The heating, if rapid, creates strong photoevaporative mass flows off the clump surfaces and drives shocks into the clumps, compressing them to high densities. The clumps lose mass on relatively short timescales. The evolution of an individual clump is found to be sensitive to three dimensionless parameters: eta(c0), the ratio of the initial column density of the clump to the column N-0 similar to 10(21) cm(-2) of a warm FUV-heated surface region;, the ratio of the sound speed in the heated surface to that in the cold clump material; and t(FUV)/t(c), the ratio of the "turn-on time" t(FUV) of the heating flux on a clump to its initial sound crossing time t(c). The evolution also depends on whether a con ning interclump medium exists or whether the interclump region has negligible pressure, as is the case for turbulence-generated clumps. In this paper, we use spherical one-dimensional numerical hydrodynamic models as well as approximate analytical models to study the dependence of clump photoevaporation on the physical parameters of the clump and to derive the dynamical evolution, mass-loss rates, and photoevaporative timescales of a clump for a variety of astrophysical situations. Turbulent clumps evolve so that their column densities are equal to a critical value determined by the local FUV field and typically have short photoevaporation timescales, similar to10(4)-10(5) yr for a 1 M-circle dot clump in a typical star-forming region (eta(c0) = 10, v = 10). Clumps with insufficient magnetic pressure support and in strong FUV fields may be driven to collapse by the compressional effect of converging shock waves. We also estimate the rocket effect on photoevaporating clumps and find that it is significant only for the smallest clumps, with sizes much less than the extent of the PDR itself. Clumps that are confined by an interclump medium may either get completely photoevaporated or preserve a shielded core with a warm, dissociated, protective shell that absorbs the incident FUV flux. We compare our results with observations of some well-studied PDRs: the Orion Bar, M17 SW, NGC 2023, and the Rosette Nebula. The data are consistent with both interpretations of clump origin, turbulence, and pressure confinement, with a slight indication for favoring the turbulent model for clumps over pressure-confined clumps. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 65 TC 54 Z9 54 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD JUL 1 PY 2002 VL 573 IS 1 BP 215 EP 237 DI 10.1086/340556 PN 1 PG 23 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 564YD UT WOS:000176340400022 ER PT J AU Lane, BF Creech-Eakman, MJ Nordgren, TE AF Lane, BF Creech-Eakman, MJ Nordgren, TE TI Long-baseline interferometric observations of Cepheids SO ASTROPHYSICAL JOURNAL LA English DT Article DE Cepheids; stars : fundamental parameters; stars : individual (eta Aquilae, zeta Geminorum); techniques : interferometric ID PALOMAR TESTBED INTERFEROMETER; PERIOD-LUMINOSITY RELATION; VISUAL SURFACE BRIGHTNESS; FUNDAMENTAL PARAMETERS; ANGULAR DIAMETERS; RADIUS RELATION; LINE-PROFILES; VARIABLES; CALIBRATION; DISTANCES AB We present observations of the Galactic Cepheids eta Aql and zeta Gem. Our observations are able to resolve the diameter changes associated with pulsation. This allows us to determine the distance to the Cepheids independent of photometric observations. We determine a distance to eta Aql of 320 +/- 32 pc and a distance to zeta Gem of 362 +/- 38 pc. These observations allow us to calibrate surface brightness relations for use in extragalactic distance determination. They also provide a measurement of the mean diameter of these Cepheids, which is useful in constructing structural models of this class of star. C1 CALTECH, Dept Geol & Planetary Sci, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Redlands, Dept Phys, Redlands, CA 92373 USA. RP Lane, BF (reprint author), CALTECH, Dept Geol & Planetary Sci, MS 150-21, Pasadena, CA 91125 USA. NR 45 TC 49 Z9 49 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 JUL 1 PY 2002 VL 573 IS 1 BP 330 EP 337 DI 10.1086/340558 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 564YD UT WOS:000176340400031 ER PT J AU Burrows, A Burgasser, AJ Kirkpatrick, JD Liebert, J Milsom, JA Sudarsky, D Hubeny, I AF Burrows, A Burgasser, AJ Kirkpatrick, JD Liebert, J Milsom, JA Sudarsky, D Hubeny, I TI Theoretical spectral models of T dwarfs at short wavelengths and their comparison with data SO ASTROPHYSICAL JOURNAL LA English DT Article DE infrared : stars; stars : atmospheres; stars : fundamental parameters; stars : low mass, brown dwarfs; techniques : spectroscopic ID DIGITAL SKY SURVEY; COOL BROWN DWARF; SURVEY COMMISSIONING DATA; EXTRASOLAR GIANT PLANETS; GLIESE 229B; INFRARED-ABSORPTION; DUSTY PHOTOSPHERES; METHANE; DISCOVERY; ATMOSPHERES AB We have generated new, self-consistent spectral and atmosphere models for the effective temperature range 600 1300 K thought to encompass the known T dwarfs. For the first time, theoretical models are compared with a family of measured T dwarf spectra at wavelengths shortward of similar to1.0 mum. By defining spectral indices and standard colors in the optical and very near-infrared, we explore the theoretical systematics with T-eff, gravity, and metallicity. We conclude that the short-wavelength range is rich in diagnostics that complement those in the near-infrared now used for spectral subtyping. We also conclude that the wings of the Na D and K I (7700 Angstrom) resonance lines and aggressive rainout of heavy metals (with the resulting enhancement of the sodium and potassium abundances at altitude) are required to fit the new data shortward of 1.0 mum. Furthermore, we find that the water bands weaken with increasing gravity, that modest decreases in metallicity enhance the effect in the optical of the sodium and potassium lines, and that at low values of T e, in a reversal of the normal pattern, optical spectra become bluer with further decreases in T-eff. Moreover, we conclude that T dwarf subtype is not a function of T-eff alone but that it is a nontrivial function of gravity and metallicity as well. As do Marley and coworkers in their 2002 work, we see evidence in early T dwarf atmospheres of a residual effect of clouds. With cloudless models, we obtain spectral fits to the two late T dwarfs with known parallaxes, but a residual effect of clouds on the emergent spectra of even late T dwarfs cannot yet be discounted. However, our focus is not on detailed fits to individual objects but on the interpretation of the overall spectral and color trends of the entire class of T dwarfs, as seen at shorter wavelengths. C1 Univ Arizona, Dept Astron, Tucson, AZ 85721 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. CALTECH, Div Phys, Pasadena, CA 91125 USA. CALTECH, Ctr Infrared Proc & Anal, Pasadena, CA 91125 USA. Univ Arizona, Dept Phys, Tucson, AZ 85721 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Univ Arizona, Dept Astron, 933 N Cherry Ave, Tucson, AZ 85721 USA. EM burrows@jupiter.as.arizona.edu; diver@its.caltech.edu; davy@ipac.caltech.edu; liebert@as.arizona.edu; milsom@physics.arizona.edu; sudarsky@as.arizona.edu; hubeny@tlusty.gsfc.nasa.gov NR 65 TC 58 Z9 58 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 JUL 1 PY 2002 VL 573 IS 1 BP 394 EP 417 DI 10.1086/340584 PN 1 PG 24 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 564YD UT WOS:000176340400036 ER PT J AU Marsh, KA Silverstone, MD Becklin, EE Koerner, DW Werner, MW Weinberger, AJ Ressler, ME AF Marsh, KA Silverstone, MD Becklin, EE Koerner, DW Werner, MW Weinberger, AJ Ressler, ME TI Mid-infrared images of the debris disk around HD 141569 SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; infrared : stars; planetary systems; stars : individual (HD 141569) ID MILLIMETER-WAVE PROPERTIES; MAIN-SEQUENCE STARS; VEGA-LIKE SYSTEMS; CIRCUMSTELLAR DISK; BETA-PICTORIS; HD-141569; EMISSION; NICMOS AB We have imaged the circumstellar debris disk around the A0 Ve/B9.5 Ve star HD 141569 ( D = 99 pc), at lambda = 12.5, 17.9, and 20.8 mum using the Keck II telescope, and confirm the general morphology from other recently published mid-infrared observations. Model fits to an assumed at radially symmetric dust disk yield an inclination i = 53degrees +/- 5degrees and a position angle of -6degrees +/- 4degrees for the tilt axis and indicate the presence of a depression in optical depth by a factor of about 4 within a radial distance of 30 AU (0".3) from the star. Such a depression is suggestive of a density depletion and is consistent with published spectral energy distributions that indicate the absence of a near-infrared excess even though a mid-infrared excess is present. Our mid-infrared results, in conjunction with previously published near-infrared scattering images, suggest that the two wavelength regimes are viewing, respectively, the inner and outer parts of a common disk structure, which is dominated by small ( probably submicron) grains throughout. C1 CALTECH, Ctr Infrared Proc & Anal, Pasadena, CA 91125 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Univ Calif Los Angeles, Div Astron & Astrophys, Los Angeles, CA 90095 USA. Univ Penn, Philadelphia, PA 19103 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Carnegie Inst Washington, Dept Terr Magnetism, Washington, DC 20015 USA. RP Marsh, KA (reprint author), CALTECH, Ctr Infrared Proc & Anal, MS 100-22, Pasadena, CA 91125 USA. NR 26 TC 42 Z9 42 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 JUL 1 PY 2002 VL 573 IS 1 BP 425 EP 430 DI 10.1086/340488 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 564YD UT WOS:000176340400038 ER PT J AU Torsti, J Kocharov, L Laivola, J Lehtinen, N Kaiser, ML Reiner, MJ AF Torsti, J Kocharov, L Laivola, J Lehtinen, N Kaiser, ML Reiner, MJ TI Solar particle event with exceptionally high He-3 enhancement in the energy range up to 50 MeV nucleon SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : abundances; Sun : particle emission; Sun : radio radiation ID INTERPLANETARY SHOCKS; FLARES AB We have surveyed the He-3-rich solar particle events in the energy range of greater than 15 MeV nucleon(-1) observed with the energetic particle instrument ERNE (the Energetic and Relativistic Nuclei and Electron experiment) on board the Solar and Heliospheric Observatory during 1999-2000. The survey reveals the exceptional event of 2000 October 29, with very strong 3 He enhancement persisting over the high-energy range, up to 50 MeV nucleon. This is the first time that the He-3/He-4 > 1 has been recorded at above 10 MeV nucleon. We present the first ever measurement of the He-3 energy spectrum in such an event. The particle event was associated with an impulsive flare and an interplanetary shock wave. The type II radio burst was observed with the WAVES experiment on board the Wind spacecraft before and then simultaneously with the He-3-rich event registered with ERNE. The analysis shows that the high-energy He-3-rich event refers to the flare material reaccelerated by the interplanetary coronal mass ejection (CME). Onset of the high-energy He-3-rich event was observed in the far upstream region, when the CME-driven shock was at about 0.3 AU from the Sun. A spectrum of protons and spectra of the two helium isotopes closely resemble an exponent in the ion speed. C1 Univ Turku, Vaisala Inst Space Phys & Astron, FIN-20014 Turku, Finland. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Raytheon Informat Technol & Sci Serv, Lanham, MD 20706 USA. RP Torsti, J (reprint author), Univ Turku, Vaisala Inst Space Phys & Astron, FIN-20014 Turku, Finland. NR 18 TC 19 Z9 19 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 1 PY 2002 VL 573 IS 1 BP L59 EP L63 DI 10.1086/341936 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 564YF UT WOS:000176340600014 ER PT J AU Beasley, AJ Gordon, D Peck, AB Petrov, L MacMillan, DS Fomalont, EB Ma, C AF Beasley, AJ Gordon, D Peck, AB Petrov, L MacMillan, DS Fomalont, EB Ma, C TI The VLBA Calibrator Survey - VCSI SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE astrometry; radio continuum : general; reference systems; surveys; techniques : interferometric ID COMPACT SYMMETRIC OBJECTS; BASE-LINE INTERFEROMETRY; MHZ SKY SURVEY; ASTROMETRIC SURVEY; HIPPARCOS-CATALOG; REFERENCE-FRAME; RADIO-SOURCES; COINS SAMPLE; MISSION; GALAXY AB A catalog containing milliarcsecond-accurate positions of 1332 extragalactic radio sources distributed over the northern sky is presented the Very Long Baseline Array Calibrator Survey ( VCS1). The positions have been derived from astrometric analysis of dual-frequency 2.3 and 8.4 GHz VLBA snapshot observations; in a majority of cases, images of the sources are also available. These radio sources are suitable for use in geodetic and astrometric experiments, and as phase-reference calibrators in high-sensitivity astronomical imaging. The VCS1 is the largest high-resolution radio survey ever undertaken and triples the number of sources available to the radio astronomy community for VLBI applications. In addition to the astrometric role, this survey can be used in active galactic nuclei, Galactic, gravitational lens, and cosmological studies. C1 CALTECH, Owens Valley Radio Observ, Big Pine, CA 93513 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Raytheon ITSS, Greenbelt, MD 20771 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. NVI Inc, Greenbelt, MD 20771 USA. Natl Radio Astron Observ, Charlottesville, VA 22903 USA. RP Beasley, AJ (reprint author), CALTECH, Owens Valley Radio Observ, POB 968, Big Pine, CA 93513 USA. RI Ma, Chopo/D-4751-2012 NR 39 TC 188 Z9 190 U1 0 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD JUL PY 2002 VL 141 IS 1 BP 13 EP 21 DI 10.1086/339806 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 564XW UT WOS:000176339700002 ER PT J AU Neri, DF Oyung, RL Colletti, LM Mallis, MM Tam, PY Dinges, DF AF Neri, DF Oyung, RL Colletti, LM Mallis, MM Tam, PY Dinges, DF TI Controlled breaks as a fatigue countermeasure on the flight deck SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article DE breaks; fatigue; flight crews; EEG; vigilance; alertness ID PERFORMANCE; WAKEFULNESS; EXERCISE; MOOD; TASK; WORK AB Background: A major challenge for flight crews is the need to maintain vigilance during long, highly automated nighttime flights. No system currently exists to assist in managing alertness, and countermeasure options are limited. Surveys reveal many pilots use breaks as an in-flight countermeasure, but there have been no controlled studies of their effectiveness. Hypothesis: We hypothesized that brief, regular breaks could improve alertness and performance during an overnight flight. Methods: A 6-h, uneventful, nighttime flight in a Boeing 747-400 flight simulator was flown by fourteen two-man crews. The 14 subjects in the treatment group received 5 short breaks spaced hourly during cruise; the 14 subjects in the control group received I break in the middle of cruise. Continuous EEG/FOG, subjective sleepiness, and psychomotor vigilance performance data were collected. Results: During the latter part of the night, the treatment group showed significant reductions for 15 min post-break in slow eye movements, theta-band activity, and unintended sleep episodes compared with the control group. The treatment group reported significantly greater subjective alertness for up to 25 min post-break, with strongest effects near the time of the circadian trough. There was no evidence of objective vigilance performance improvement at 15-25 min post-break, with expected performance deterioration occurring due to elevated sleep drive and circadian time. Conclusions: The physiological and subjective data indicate the breaks reduced nighttime sleepiness for at least 15 min post-break and may have masked sleepiness for up to 25 min, suggesting the potential usefulness of short-duration breaks as an in-flight fatigue countermeasure. C1 NASA, Ames Res Ctr, Fatigue Countermeasures Grp, Moffett Field, CA 94035 USA. Univ Penn, Sch Med, Dept Psychiat, Div Sleep & Chronobiol, Philadelphia, PA 19104 USA. RP Neri, DF (reprint author), Off Naval Res ONR 342, Cognit Neural & Biomol Sci & Technol Div, 800 N Quincy St, Arlington, VA 22217 USA. NR 29 TC 44 Z9 47 U1 2 U2 5 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 JUL PY 2002 VL 73 IS 7 BP 654 EP 664 PG 11 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA 568BP UT WOS:000176522800006 PM 12137101 ER PT J AU Kotzar, G Freas, M Abel, P Fleischman, A Roy, S Zorman, C Moran, JM Melzak, J AF Kotzar, G Freas, M Abel, P Fleischman, A Roy, S Zorman, C Moran, JM Melzak, J TI Evaluation of MEMS materials of construction for implantable medical devices SO BIOMATERIALS LA English DT Article DE BioMEMS; biocompatibility; implant; sterilization; ISO 10993 ID SILICON-CARBIDE; IN-VITRO; COATING MATERIALS; BIOCOMPATIBILITY; TITANIUM; CELLS; BONE; HYDROXYAPATITE; FIBROBLASTS; ELECTRODE AB Medical de, ices based on microelectro-mechanical systems (MEMS) platforms are currently being proposed for a wide variety of implantable applications. However, biocompatibility data for typical MEMS materials of construction and processing. obtained front standard tests currently recognized by regulatory agencies, has not been published. Likewise, the effects of common sterilization techniques on MEMS material properties hake not been reported. Medical device regutatory requirements dictate that materials that Lire biocompatibility, tested be processed and sterilized in a manner equivalent to the final production device. Material, processing. and sterilization method can impact the final result. Six candidate materials for implantable MEMS devices, and one encapsulating material, were fabricated using typical MEMS processing techniques and sterilized. All seven materials were evaluated using a baseline battery of ISO 10993 physicochemical and biocompatibility tests. In addition. samples of these materials,here evaluated using a scanning electron microscope (SEM) pre- and post-sterilization. While not addressing all facets of ISO 10993 testing, the biocompatibility, and SEM data indicate rev, concerns about use of these materials in implant applications. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 BIOMEC Inc, Cleveland, OH 44114 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Cleveland Clin Fdn, Lerner Res Inst, Cleveland, OH 44195 USA. Case Western Reserve Univ, Cleveland, OH 44106 USA. RP Freas, M (reprint author), BIOMEC Inc, 1771 E 30th St, Cleveland, OH 44114 USA. OI Zorman, Christian/0000-0001-9773-9351 NR 60 TC 236 Z9 241 U1 9 U2 59 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 JUL PY 2002 VL 23 IS 13 BP 2737 EP 2750 AR PII S0142-9612(02)00007-8 DI 10.1016/S0142-9612(02)00007-8 PG 14 WC Engineering, Biomedical; Materials Science, Biomaterials SC Engineering; Materials Science GA 554DM UT WOS:000175718600014 PM 12059024 ER PT J AU Beard, DA Liang, SC Qian, H AF Beard, DA Liang, SC Qian, H TI Energy balance for analysis of complex metabolic networks SO BIOPHYSICAL JOURNAL LA English DT Article ID PATHWAY ANALYSIS; BASIC CONCEPTS; FLUX ANALYSIS; CAPABILITIES; CONSTRAINTS AB Predicting behavior of large-scale biochemical networks represents one of the greatest challenges of bioinformatics and computational biology. Computational tools for predicting fluxes in biochemical networks are applied in the fields of integrated and systems biology, bioinformatics, and genomics, and to aid in drug discovery and identification of potential drug targets. Approaches, such as flux balance analysis (FBA), that account for the known stoichiometry of the reaction network while avoiding implementation of detailed reaction kinetics are promising tools for the analysis of large complex networks. Here we introduce energy balance analysis (EBA)-the theory and methodology for enforcing the laws of thermodynamics in such simulations-making the results more physically realistic and revealing greater insight into the regulatory and control mechanisms operating in complex large-scale systems. We show that EBA eliminates thermodynamically infeasible results associated with FBA. C1 Univ Washington, Dept Bioengn, Seattle, WA 98195 USA. Univ Washington, Dept Math Appl, Seattle, WA 98195 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Beard, DA (reprint author), Univ Washington, Dept Bioengn, Box 352255, Seattle, WA 98195 USA. FU NCRR NIH HHS [NCRR-1243, NCRR-12609] NR 24 TC 213 Z9 220 U1 0 U2 25 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD JUL PY 2002 VL 83 IS 1 BP 79 EP 86 PG 8 WC Biophysics SC Biophysics GA 566UC UT WOS:000176445800007 PM 12080101 ER PT J AU Calhoun, PC Adhami, R Joiner, LL AF Calhoun, PC Adhami, R Joiner, LL TI Application of horizon sensor measurements in Kalman filtering techniques for on-board orbit navigation during aerobraking SO CIRCUITS SYSTEMS AND SIGNAL PROCESSING LA English DT Article DE Kalman filtering; extended Kalman filtering; tracking; aerobraking; orbit navigation; horizon centers AB The problem of determining the dynamic state vector, i.e., the position and velocity of a spacecraft as it proceeds along its trajectory, is known as orbit navigation. One approach to this problem is to process a sequence of measurements of the position or velocity through some form of batch or recursive estimation. Numerous approaches to orbit navigation that utilize Kalman filtering of on-board sensors are described in the literature. These sensors include the global positioning system (GPS), magnetic field, star trackers, and horizon sensor measurements. Optical measurements, such as star cameras and horizon sensors, have the advantage of being applied to high-altitude Earth orbits and planetary missions where GPS and magnetic field measurements are not available. In this study, the extended Kalman filtering technique, using horizon sensor measurements, is applied to the problem of real-time on-board navigation during the "aerobraking" phase of a Mars mission. The technique of aerobraking is used to lower a satellite into its final mission orbit from an initial highly elliptic orbit using successive drag passes at the periapsis to control the removal of orbital energy. The results of Monte Carlo simulations of the inplane orbit dynamics demonstrate the usefulness of the extended Kalman filter approach in the navigation of spacecraft during an aerobraking operation. An improvement in the filter performance is realized when the Kalman filter prototype is augmented with an atmospheric drag force model. C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. Univ Alabama, Huntsville, AL 35899 USA. RP Calhoun, PC (reprint author), NASA, Langley Res Ctr, Hampton, VA 23665 USA. NR 11 TC 1 Z9 1 U1 0 U2 1 PU BIRKHAUSER BOSTON INC PI CAMBRIDGE PA 675 MASSACHUSETTS AVE, CAMBRIDGE, MA 02139 USA SN 0278-081X J9 CIRC SYST SIGNAL PR JI Circuits Syst. Signal Process. PD JUL-AUG PY 2002 VL 21 IS 4 BP 399 EP 413 DI 10.1007/s00034-002-0426-0 PG 15 WC Engineering, Electrical & Electronic SC Engineering GA 588RE UT WOS:000177713800003 ER PT J AU Vander Wal, RL Hall, LJ AF Vander Wal, RL Hall, LJ TI Ferrocene as a precursor reagent for metal-catalyzed carbon nanotubes: Competing effects SO COMBUSTION AND FLAME LA English DT Article ID CO-H2-H2O GAS-MIXTURES; NON-PREMIXED FLAMES; HYDROCARBON FORMATION; ETHYLENE FLAMES; IRON CATALYST; CO FOILS; DEPOSITION; GROWTH; HYDROGEN; MONOXIDE AB Single-walled nanotube (SWNT) synthesis is studied in a pyrolysis flame configuration seeded with ferrocene as a catalyst precursor reagent. The concentration of ferrocene is prominent among the factors that determine SWNT inception, growth, and catalyst particle deactivation. This reflects ferrocene's role as metal catalyst precursor and as a source of cyclopentadiene species upon its thermal decomposition. Results with different reactant gas mixtures and flows are presented and interpreted in light of a SWNT synthesis mechanism and catalyst deactivation processes. (C) 2002 by The Combustion Institute. C1 NASA Glenn, NCMR, Cleveland, OH 44135 USA. RP NASA Glenn, NCMR, MS 110-3, Cleveland, OH 44135 USA. EM randy.vanderwal@grc.nasa.gov NR 45 TC 43 Z9 43 U1 0 U2 18 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0010-2180 EI 1556-2921 J9 COMBUST FLAME JI Combust. Flame PD JUL PY 2002 VL 130 IS 1-2 BP 27 EP 36 AR PII S0010-2180(02)00358-9 DI 10.1016/S0010-2180(02)00358-9 PG 10 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA 574EY UT WOS:000176876500003 ER PT J AU Vander Wal, RL AF Vander Wal, RL TI Fe-catalyzed single-walled carbon nanotube synthesis within a flame environment SO COMBUSTION AND FLAME LA English DT Article ID CO-H2-H2O GAS-MIXTURES; LASER-ABLATION PROCESS; GROWTH MECHANISMS; IRON CATALYST; CO FOILS; DEPOSITION; MONOXIDE; HYDROGEN; PYROLYSIS; DISPROPORTIONATION AB Flame synthesis of single walled carbon nanotubes (SWNT) is demonstrated using Fe nanoparticles [introduced by nebulization of an iron (III) nitrate salt solution] within a pyrolysis flame configuration. The roles of the nebulized solution solvent, metal nitrate concentration, pyrolysis flame gas composition, and the surrounding flame gas composition are interpreted as reflecting suitable concentrations of reactants without excessive pyrolysis products or deactivating species. The preferential reactivity of the catalyst particle toward CO and not toward C2H2 is understood as reflecting nanoparticle restructuring, interactions between co-adsorbates and reactant pyrolysis products. Fe is found to exhibit preferential reactivity toward CO for SWNT catalysis with this reactivity being strongly dependent upon catalyst particle size within our flame conditions. H-2 appears to moderate the dissociative adsorption through electronic interactions with co-adsorbates, mediated by the catalyst nanoparticle and by maintaining a catalytically clean particle surface. (C) 2002 by The Combustion Institute. C1 NASA, Glenn Res Ctr, NCMR, Cleveland, OH 44135 USA. RP NASA, Glenn Res Ctr, NCMR, MS 110-3, Cleveland, OH 44135 USA. NR 57 TC 59 Z9 59 U1 1 U2 21 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0010-2180 EI 1556-2921 J9 COMBUST FLAME JI Combust. Flame PD JUL PY 2002 VL 130 IS 1-2 BP 37 EP 47 AR PII S0010-2180(02)00360-7 DI 10.1016/S0010-2180(02)00360-7 PG 11 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA 574EY UT WOS:000176876500004 ER PT J AU Krueger, R Paris, IL O'Brien, TK Minguet, PJ AF Krueger, R Paris, IL O'Brien, TK Minguet, PJ TI Comparison of 2D finite element modeling assumptions with results from 3D analysis for composite skin-stiffener debonding SO COMPOSITE STRUCTURES LA English DT Article; Proceedings Paper CT 11th International Conference on Composite Structures (ICCS 11) CY NOV 19-21, 2001 CL MONASH UNIV, MELBOURNE, AUSTRALIA HO MONASH UNIV AB The influence of two-dimensional finite element modeling assumptions on the debonding prediction for skin-stiffener specimens was investigated. Geometrically nonlinear finite element analyses using two-dimensional plane-stress and plane-strain elements as well as three different generalized plane-strain type approaches were performed. The computed skin and flange strains. transverse tensile stresses and energy release rates were compared to results obtained from three-dimensional simulations. The study showed that for strains and energy release rate computations the generalized plane-strain assumptions yielded results closest to the full three-dimensional analysis. For computed transverse tensile stresses the plane-stress assumption gave the best agreement. Based on this study it is recommended that results from plane-stress and plane-strain models be used as upper and lower bounds. The results from generalized plane-strain models fall between the results obtained from plane-stress and plane-strain models. Two-dimensional models may also be used to qualitatively evaluate the stress distribution in a ply and the variation of energy release rates and mixed mode ratios with delamination length. For more accurate predictions, however, a three-dimensional analysis is required. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 NASA, Langley Res Ctr, USA, Res Lab,Vehicle Technol Directorate, Hampton, VA 23681 USA. NASA, Langley Res Ctr, Natl Res Council, Hampton, VA 23681 USA. NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. RP O'Brien, TK (reprint author), NASA, Langley Res Ctr, USA, Res Lab,Vehicle Technol Directorate, Mail Stop 188E, Hampton, VA 23681 USA. RI Krueger, Ronald/G-5356-2015 NR 17 TC 25 Z9 27 U1 1 U2 5 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0263-8223 J9 COMPOS STRUCT JI Compos. Struct. PD JUL-SEP PY 2002 VL 57 IS 1-4 BP 161 EP 168 AR PII S0263-8223(02)00079-X DI 10.1016/S0263-8223(02)00079-X PG 8 WC Materials Science, Composites SC Materials Science GA 596AZ UT WOS:000178142700019 ER PT J AU O'Brien, TK Paris, IL AF O'Brien, TK Paris, IL TI Exploratory investigation of failure mechanisms in transition regions between solid laminates and X-cor((R)) truss sandwich SO COMPOSITE STRUCTURES LA English DT Article; Proceedings Paper CT 11th International Conference on Composite Structures (ICCS 11) CY NOV 19-21, 2001 CL MONASH UNIV, MELBOURNE, AUSTRALIA HO MONASH UNIV DE composites; X-cor((R)) truss sandwich; failure modes AB Small sub-component specimens consisting of solid laminates at the ends that transition to X-cor(R) truss sandwich in the center, were tested in a combination of three point bending, uni-axial tension, and combined tension and bending. The failure process in the transition region was documented for each loading using digital video and high-resolution cameras. For the three-point bending tests, most of the deformation occurred in the solid laminate regions on either end of the specimen. Some pin debonding from the skin of the X-cor(R) truss sandwich was observed in the transition region and was accompanied by audible "pings" throughout the loading. Tension loaded specimens failed in the sandwich skin in the middle of the gage length, accompanied by separation of the sandwich core from the back skin and by delamination between the top skin and bottom skin at the transition region. The pinging associated with pin debonding occurred as the load was increased. However, the frequency of the pinging exceeded any visual observations of pin debonding in the video of the transition region. For specimens tested in combined tension and bending, the greatest amount of ringing occurred during initial application of the axial load. High-resolution. images in the transition region indicated that the pinging corresponded to pins debonding and buckling due to the through-thickness Poisson contraction of the specimen. This buckling continued to a much smaller extent as the transverse load was applied. (C) 2002 Published by Elsevier Science Ltd. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP O'Brien, TK (reprint author), NASA, Langley Res Ctr, Mail Stop 188E, Hampton, VA 23681 USA. NR 1 TC 23 Z9 28 U1 2 U2 7 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0263-8223 J9 COMPOS STRUCT JI Compos. Struct. PD JUL-SEP PY 2002 VL 57 IS 1-4 BP 189 EP 204 AR PII S0263-8223(02)00083-1 DI 10.1016/S0263-8223(02)00083-1 PG 16 WC Materials Science, Composites SC Materials Science GA 596AZ UT WOS:000178142700023 ER PT J AU Bozzolo, GH Khalil, J Noebe, RD AF Bozzolo, GH Khalil, J Noebe, RD TI Modeling of the site preference in ternary B2-ordered Ni-Al-Fe alloys SO COMPUTATIONAL MATERIALS SCIENCE LA English DT Article DE nickel; aluminum; iron; defect structure; computational methods ID MECHANICAL-PROPERTIES; ADDITIONS; IRON AB The underlying equilibrium structure, site substitution behavior, and lattice parameter of ternary Ni-Fe-Al alloys are determined via Monte Carlo-Metropolis computer simulations and analytical calculations using the BFS method for alloys for the energetics. As a result of the theoretical calculations presented, a simple approach based on the energetics of small atomic clusters is introduced to explain the observed site preference schemes. (C) 2002 Elsevier Science B.V. All rights reserved. C1 NASA Glenn Res Ctr, Cleveland, OH 44135 USA. Ohio Aerosp Inst, Cleveland, OH 44142 USA. RP Bozzolo, GH (reprint author), NASA Glenn Res Ctr, Lewis Field,Mail Stop 23-2, Cleveland, OH 44135 USA. NR 23 TC 34 Z9 34 U1 2 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0927-0256 J9 COMP MATER SCI JI Comput. Mater. Sci. PD JUL PY 2002 VL 24 IS 4 BP 457 EP 480 AR PII S0927-0256(02)00153-2 DI 10.1016/S0927-0256(02)00153-2 PG 24 WC Materials Science, Multidisciplinary SC Materials Science GA 576ZW UT WOS:000177037900005 ER PT J AU Papalexandris, MV Leonard, A Dimotakis, PE AF Papalexandris, MV Leonard, A Dimotakis, PE TI Unsplit algorithms for multidimensional systems of hyperbolic conservation laws with source terms SO COMPUTERS & MATHEMATICS WITH APPLICATIONS LA English DT Article DE unsplit schemes; conservation laws; hyperbolic PDEs; source terms; detonations ID DETONATION-WAVES; EULER-EQUATIONS; SCHEMES; SIMULATIONS; GODUNOV AB This work describes an unsplit, second-order accurate algorithm for multidimensional systems of hyperbolic conservation laws with source terms, such as the compressible Euler equations for reacting flows. It is a MUSCL-type, shock-capturing scheme that integrates all terms of the governing equations simultaneously, in a single time-step, thus avoiding dimensional or time-splitting. Appropriate families of space-time manifolds are introduced, along which the conservation equations decouple to the characteristic equations of the corresponding 1-D homogeneous system. The local geometry of these manifolds depends on the source terms and the spatial derivatives of the flow variables. Numerical integration of the characteristic equations is performed along these manifolds in the upwinding part of the algorithm. Numerical simulations of two-dimensional detonations with simplified kinetics are performed to test the accuracy and robustness of the algorithm. These flows are unstable for a wide range of parameters and may exhibit chaotic behavior. Grid-convergence studies and comparisons with earlier results, obtained with traditional schemes, are presented. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 CALTECH, Grad Aeronaut Labs, Pasadena, CA 91125 USA. RP CALTECH, Jet Prop Lab, Mail Code 306-336, Pasadena, CA 91109 USA. NR 25 TC 11 Z9 11 U1 0 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0898-1221 EI 1873-7668 J9 COMPUT MATH APPL JI Comput. Math. Appl. PD JUL PY 2002 VL 44 IS 1-2 BP 25 EP 49 AR PII S0898-1221(02)00128-1 DI 10.1016/S0898-1221(02)00128-1 PG 25 WC Mathematics, Applied SC Mathematics GA 559ZF UT WOS:000176056000004 ER PT J AU Ramsey, J Gazis, P Roush, T Spirtes, P Glymour, C AF Ramsey, J Gazis, P Roush, T Spirtes, P Glymour, C TI Automated remote sensing with near infrared reflectance spectra: Carbonate recognition SO DATA MINING AND KNOWLEDGE DISCOVERY LA English DT Article DE reflectance spectroscopy; mineralogy; artificial intelligence; Bayes nets; TETRAD; carbonates; mars AB Reflectance spectroscopy is a standard tool for studying the mineral composition of rock and soil samples and for remote sensing of terrestrial and extraterrestrial surfaces. We describe research on automated methods of mineral identification from reflectance spectra and give evidence that a simple algorithm, adapted from a well-known search procedure for Bayes nets, identifies the most frequently occurring classes of carbonates with reliability equal to or greater than that of human experts. We compare the reliability of the procedure to the reliability of several other automated methods adapted to the same purpose. Evidence is given that the procedure can be applied to some other mineral classes as well. Since the procedure is fast with low memory requirements, it is suitable for on-board scientific analysis by orbiters or surface rovers. C1 Carnegie Mellon Univ, Dept Philosophy, Pittsburgh, PA 15213 USA. NASA, Ames Res Ctr, Mt View, CA USA. Univ W Florida, Inst Human & Machine Cognit, Pensacola, FL 32514 USA. Carnegie Mellon Univ, Ctr Automated Learning & Discovery, Pittsburgh, PA 15213 USA. RP Ramsey, J (reprint author), Carnegie Mellon Univ, Dept Philosophy, Pittsburgh, PA 15213 USA. NR 15 TC 16 Z9 16 U1 0 U2 2 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 1384-5810 J9 DATA MIN KNOWL DISC JI Data Min. Knowl. Discov. PD JUL PY 2002 VL 6 IS 3 BP 277 EP 293 DI 10.1023/A:1015421711749 PG 17 WC Computer Science, Artificial Intelligence; Computer Science, Information Systems SC Computer Science GA 550LB UT WOS:000175503600003 ER PT J AU Johns, WE Townsend, TL Fratantoni, DM Wilson, WD AF Johns, WE Townsend, TL Fratantoni, DM Wilson, WD TI On the Atlantic inflow to the Caribbean Sea (vol 49, pg 211, 2002) SO DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS LA English DT Correction C1 Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Miami, FL 33149 USA. USN, Res Lab, Stennis Space Ctr, Stennis Space Ctr, MS 39529 USA. Woods Hole Oceanog Inst, Dept Phys Oceanog, Woods Hole, MA 02543 USA. NOAA, Atlantic Oceanog & Meteorol Lab, Phys Oceanog Div, Miami, FL 33149 USA. RP Johns, WE (reprint author), Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, 4600 Rickenbacker Causeway, Miami, FL 33149 USA. RI Fratantoni, David/C-7121-2011 NR 1 TC 1 Z9 1 U1 2 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0967-0637 J9 DEEP-SEA RES PT I JI Deep-Sea Res. Part I-Oceanogr. Res. Pap. PD JUL PY 2002 VL 49 IS 7 BP 1307 EP 1307 AR PII S0967-0637(02)00026-2 DI 10.1016/S0967-0637(02)00026-2 PG 1 WC Oceanography SC Oceanography GA 589UC UT WOS:000177777900011 ER PT J AU Ivanov, AV Kononkova, NN Zolensky, ME Migdisova, LF Stroganov, IA AF Ivanov, AV Kononkova, NN Zolensky, ME Migdisova, LF Stroganov, IA TI Kaidun meteorite: An alkaline rock fragment SO GEOCHEMISTRY INTERNATIONAL LA English DT Article ID MINERALOGY C1 Russian Acad Sci, VI Vernadskii Inst Geochem & Analyt Chem, Moscow 117975, Russia. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Ivanov, AV (reprint author), Russian Acad Sci, VI Vernadskii Inst Geochem & Analyt Chem, Ul Kosygina 19, Moscow 117975, Russia. NR 13 TC 1 Z9 1 U1 0 U2 1 PU INTERPERIODICA PI BIRMINGHAM PA PO BOX 1831, BIRMINGHAM, AL 35201-1831 USA SN 0016-7029 J9 GEOCHEM INT+ JI Geochem. Int. PD JUL PY 2002 VL 40 IS 7 BP 694 EP 697 PG 4 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 583EY UT WOS:000177394700008 ER PT J AU Cox, BL Popa, R Bazylinski, DA Lanoil, B Douglas, S Belz, A Engler, DL Nealson, KH AF Cox, BL Popa, R Bazylinski, DA Lanoil, B Douglas, S Belz, A Engler, DL Nealson, KH TI Organization and elemental analysis of P-, S-, and Fe-rich inclusions in a population of freshwater magnetococci SO GEOMICROBIOLOGY JOURNAL LA English DT Article DE magnetococci; magnetite; ESEM; TEM; sulfur inclusions; phosphorus inclusions ID MAGNETOTACTIC BACTERIA; MAGNETITE FORMATION; AQUASPIRILLUM-MAGNETOTACTICUM; ELECTRON-MICROSCOPY; WATER SEDIMENT; MAGNETOSOMES; MARINE; SULFUR; POLYPHOSPHATE; SPIRILLUM AB We characterized a population of bilophotrichously flagellated freshwater magnetotactic cocci (MC), referred to as ARB-1, morphologically, chemically, and phylogenetically. Cells examined using light microscopy, fluorescence microscopy, environmental scanning electron microscopy (ESEM), and transmission electron microscopy (TEM) contained three types of intracellular inclusions placed in a specific arrangement within the cell. Elemental compositions of the inclusions were determined using energy dispersive X-ray spectroscopy (EDS) from both ESEM and TEM. The spherical to ovoid cells contained two large phosphorus-rich inclusions that occupied most of the cell volume and appeared to be enclosed in a membrane or coating. Several smaller sulfur-rich inclusions were located at the end of the cell opposite the flagellar bundles. The magnetosomes, arranged either as a cluster, a chain, or a combination of both, were located proximal to the two flagellar bundles. Magnetite was identified as the mineral phase of the magnetosomes using selected area electron diffraction (SAED) and by measuring lattice fringe spacings of the crystals. The magnetite crystals were hexagonal prisms that averaged 82 nm in length and thus fit into the single-magnetic-domain size range. Phylogenetic analysis of the 16S rRNA gene sequences suggests that it is a mixed population of MC that form a monophyletic clade distinct from but similar to other uncultured MC. C1 Jet Prop Lab, Ctr Life Detect, Pasadena, CA USA. CALTECH, Pasadena, CA 91125 USA. Iowa State Univ, Dept Microbiol, Ames, IA USA. RP Cox, BL (reprint author), Univ So Calif, Sci Hall 117,3651 Trousdale Pkwy, Los Angeles, CA 90089 USA. OI Lanoil, Brian/0000-0001-8603-8330 NR 47 TC 39 Z9 44 U1 2 U2 19 PU TAYLOR & FRANCIS INC PI PHILADELPHIA PA 325 CHESTNUT ST, SUITE 800, PHILADELPHIA, PA 19106 USA SN 0149-0451 J9 GEOMICROBIOL J JI Geomicrobiol. J. PD JUL-AUG PY 2002 VL 19 IS 4 BP 387 EP 406 DI 10.1080/01490450290098504 PG 20 WC Environmental Sciences; Geosciences, Multidisciplinary SC Environmental Sciences & Ecology; Geology GA 585NZ UT WOS:000177532300001 ER PT J AU Sommers, MG Dollhopf, ME Douglas, S AF Sommers, MG Dollhopf, ME Douglas, S TI Freshwater ferromanganese stromatolites from Lake Vermilion, Minnesota: Microbial culturing and environmental scanning electron microscopy investigations SO GEOMICROBIOLOGY JOURNAL LA English DT Article DE ESEM; ferromanganese; Lake Vermilion; nodules; oncoids; stromatolites ID MANGANESE REDUCTION; MINERAL FORMATION; OXIDATION; BACTERIA AB Lacustrine ferromanganese oxide nodules have been discovered in Lake Vermilion, northern Minnesota, USA. They occur as two morphotypes: laminated discs growing around or on cobbles ("reef- type"), and ovoid nodules on muddy gravel ("oncoidtype"). Nodules have only been found within a depth-range of similar to1 to 7 m, and no nodules were found on or in fine mud sediments. Oxide coatings on recent litter allowed estimates of growth rates between 2.3 to 3.5 mum/yr. X-ray diffraction, energy dispersive X-ray spectroscopy, and thin section and environmental scanning electron microscopy of the nodules showed microorganisms, chiefly bacteria but also including cyanobacteria, diatoms, and other protozoans, mineralized by X-ray amorphous ferromanganese oxyhydroxide compounds and forming porous granular layers. ESEM examination also revealed solid-appearing layers, with no microorganism remains. Bacterial culturing experiments were carried out using lake water, sediment, and nodule swabs and pieces as the inocula. All resulted in the growth of bacteria that reduce and/or oxidize iron and manganese, showing that metal oxidizing and reducing bacteria are ubiquitous within the lake habitats. The culturing experiments also demonstrate that the bacteria can cause the formation of solid metal oxides. The combination of culturing and ESEM investigations demonstrate the probable biogenic nature of the Lake Vermilion nodules, which are thus better termed stromatolites and oncoids. However, the solid layers suggest that some abiotic aspects play a role in the genesis of the stromatolites. It is also likely that the development of stromatolites is strongly influenced by environmental factors such as substrate and depth. C1 Univ Calif Santa Barbara, Dept Geol Sci, Santa Barbara, CA 93106 USA. Michigan State Univ, Ctr Microbial Ecol, E Lansing, MI 48824 USA. NASA JPL, Ctr Life Detect, Pasadena, CA USA. RP Sommers, MG (reprint author), Univ Calif Santa Barbara, Dept Geol Sci, Santa Barbara, CA 93106 USA. NR 45 TC 7 Z9 9 U1 1 U2 8 PU TAYLOR & FRANCIS INC PI PHILADELPHIA PA 325 CHESTNUT ST, SUITE 800, PHILADELPHIA, PA 19106 USA SN 0149-0451 J9 GEOMICROBIOL J JI Geomicrobiol. J. PD JUL-AUG PY 2002 VL 19 IS 4 BP 407 EP 427 DI 10.1080/01490450290098513 PG 21 WC Environmental Sciences; Geosciences, Multidisciplinary SC Environmental Sciences & Ecology; Geology GA 585NZ UT WOS:000177532300002 ER PT J AU Chang, SW Mende, SB Frey, HU Gallagher, DL Lepping, RP AF Chang, SW Mende, SB Frey, HU Gallagher, DL Lepping, RP TI Proton aurora dynamics in response to the IMF and solar wind variations SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID CUSP ENERGETIC IONS; EARTHS BOW SHOCK; MAGNETIC-FIELD; BOUNDARY-LAYER; LOW-ALTITUDE; LYMAN-ALPHA; ACCELERATION; SPACECRAFT; CONVECTION; GEOMETRY AB [1] On May 23, 2000, proton auroras observed by IMAGE FUV on the dayside were very dynamic. Auroral pattern at the cusp footpoint is well correlated with IMF and solar wind parameters. A proton aurora brightened at high latitude poleward from the dayside oval after solar wind ion temperature increased while solar wind density and bulk speed were steady. It then vanished after IMF turned southward. Under this IMF condition, auroral activity occurred only in the dayside oval. As IMF B-z reverted to northward, cusp proton aurora reappeared at high latitude. The location of the cusp proton aurora changes with the IMF B-y polarity, consistent with previous reports. These results suggest an upstream source for the observed high-latitude cusp proton aurora. One possible explanation is that bow shock energetic ions are transported into the cusp via the high-latitude magnetic merging process to induce optical emissions in the ionosphere. C1 Univ Alabama, Ctr Space Plasma & Aeron Res, Huntsville, AL 35899 USA. NASA, Dept Space Sci, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Chang, SW (reprint author), Natl Space Sci & Technol, SD50,320 Sparkman Dr, Huntsville, AL 35805 USA. NR 22 TC 4 Z9 4 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUL 1 PY 2002 VL 29 IS 13 AR 1648 DI 10.1029/2002GL015019 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 610MR UT WOS:000178964300008 ER PT J AU Halekas, JS Mitchell, DL Lin, RP Hood, LL Acuna, MH Binder, AB AF Halekas, JS Mitchell, DL Lin, RP Hood, LL Acuna, MH Binder, AB TI Demagnetization signatures of lunar impact craters SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID CRUSTAL MAGNETIC-ANOMALIES; BASINS; SHOCK AB [1] We investigate the crustal magnetic signatures of lunar craters using Lunar Prospector (LP) electron reflectometer data. Craters of all ages often have associated magnetic lows, showing that crustal fields were present even in pre-Nectarian times (greater than or similar to3.9 Ga). Magnetic lows extend to similar to2-4 crater radii, suggesting shock rather than thermal demagnetization. Younger craters are more likely to have clear and complete demagnetization signatures, suggesting that many older magnetic lows have been subsequently obscured. No size dependence is found for craters larger than 50 km in diameter, suggesting that demagnetization effects for all craters in this size range completely penetrate the magnetized layer. If shock demagnetization is responsible, this suggests an upper limit of similar to50 km for the depth of magnetization. Evidence of edge effects due to magnetization contrasts may show that strong far-side crustal fields are coherent at scales of similar to25 km. C1 Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Lunar Res Inst, Tucson, AZ 85747 USA. RP Halekas, JS (reprint author), Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. OI Halekas, Jasper/0000-0001-5258-6128 NR 16 TC 21 Z9 23 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUL 1 PY 2002 VL 29 IS 13 AR 1645 DI 10.1029/2001GL013924 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 610MR UT WOS:000178964300011 ER PT J AU Campbell, J Antoine, D Armstrong, R Arrigo, K Balch, W Barber, R Behrenfeld, M Bidigare, R Bishop, J Carr, ME Esaias, W Falkowski, P Hoepffner, N Iverson, R Kiefer, D Lohrenz, S Marra, J Morel, A Ryan, J Vedernikov, V Waters, K Yentsch, C Yoder, J AF Campbell, J Antoine, D Armstrong, R Arrigo, K Balch, W Barber, R Behrenfeld, M Bidigare, R Bishop, J Carr, ME Esaias, W Falkowski, P Hoepffner, N Iverson, R Kiefer, D Lohrenz, S Marra, J Morel, A Ryan, J Vedernikov, V Waters, K Yentsch, C Yoder, J TI Comparison of algorithms for estimating ocean primary production from surface chlorophyll, temperature, and irradiance SO GLOBAL BIOGEOCHEMICAL CYCLES LA English DT Article DE primary productivity; algorithms; ocean color; remote sensing; satellite; chlorophyll ID LIGHT-PHOTOSYNTHESIS MODEL; NORTH-ATLANTIC; SATELLITE CHLOROPHYLL; PHYTOPLANKTON GROWTH; CARBON; COLOR; SEA; WATERS; ZONE; FLUORESCENCE AB [1] Results of a single-blind round-robin comparison of satellite primary productivity algorithms are presented. The goal of the round-robin exercise was to determine the accuracy of the algorithms in predicting depth-integrated primary production from information amenable to remote sensing. Twelve algorithms, developed by 10 teams, were evaluated by comparing their ability to estimate depth-integrated daily production (IP, mg C m(-2)) at 89 stations in geographically diverse provinces. Algorithms were furnished information about the surface chlorophyll concentration, temperature, photosynthetic available radiation, latitude, longitude, and day of the year. Algorithm results were then compared with IP estimates derived from (14)C uptake measurements at the same stations. Estimates from the best-performing algorithms were generally within a factor of 2 of the (14)C-derived estimates. Many algorithms had systematic biases that can possibly be eliminated by reparameterizing underlying relationships. The performance of the algorithms and degree of correlation with each other were independent of the algorithms' complexity. C1 Univ New Hampshire, Inst Study Earth Oceans & Space, Ocean Proc Anal Lab, Durham, NH 03824 USA. CNRS, INSU, Lab Oceanog Villefranche, F-06238 Villefranche Sur Mer, France. Univ Paris 06, F-06238 Villefranche Sur Mer, France. SUNY Stony Brook, Marine Sci Res Ctr, Stony Brook, NY 11794 USA. Stanford Univ, Dept Geophys, Stanford, CA 94305 USA. Bigelow Lab Ocean Sci, Boothbay Harbor, ME 04575 USA. Duke Univ, Marine Lab, Nicholas Sch Environm & Earth Sci, Beaufort, NC 28516 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Hawaii, Dept Oceanog, Honolulu, HI 96822 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Rutgers State Univ, Dept Geol, New Brunswick, NJ 08901 USA. Rutgers State Univ, Inst Marine & Coastal Sci, New Brunswick, NJ 08901 USA. Commiss European Communities, Joint Res Ctr, Inst Environm & Sustainabil, Inland & Marine Waters Unit, I-21020 Ispra, Italy. Florida State Univ, Dept Oceanog, Tallahassee, FL 32306 USA. Univ So Calif, Dept Biol Sci, Los Angeles, CA 90089 USA. Univ So Mississippi, Dept Marine Sci, Stennis Space Ctr, MS 39529 USA. Columbia Univ, Lamont Doherty Earth Observ, Palisades, NY 10964 USA. Monterey Bay Aquarium & Res Inst, Moss Landing, CA 95039 USA. Russian Acad Sci, PP Shirshov Oceanol Inst, Moscow 117997, Russia. NOAA, Coastal Serv Ctr, Charleston, SC 29405 USA. Univ Rhode Isl, Grad Sch Oceanog, Narragansett, RI 02882 USA. RP Campbell, J (reprint author), Univ New Hampshire, Inst Study Earth Oceans & Space, Ocean Proc Anal Lab, Morse Hall, Durham, NH 03824 USA. EM janet.campbell@unh.edu; david@obs-vlfr.fr; rarmstrong@notes.cc.sunysb.edu; arrigo@pangea.stanford.edu; bbalch@bigelow.org; rbarber@duke.edu; mjb@neptune.gsfc.nasa.gov; bidigare@soest.hawaii.edu; JKBishop@lbl.gov; mec@pacific.jpl.nasa.gov; wayne.esaias@gsfc.nasa.gov; falko@imcs.Rutgers.edu; nicolas.hoepffner@jrc.it; riverson@ocean.fsu.edu; kiefer@physics1.usc.edu; steven.lohrenz@usm.edu; marra@ldeo.columbia.edu; morel@obs-vlfr.fr; ryjo@mbari.org; oleg@manta.sio.rssi.ru; Kirk.Waters@noaa.gov; cyentsch@bigelow.org; jyoder@gso.uri.edu RI Armstrong, Robert/C-9086-2009; Reboreda, Rosa/A-2518-2012; Antoine, David/C-3817-2013 OI Antoine, David/0000-0002-9082-2395 NR 60 TC 100 Z9 103 U1 2 U2 34 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0886-6236 J9 GLOBAL BIOGEOCHEM CY JI Glob. Biogeochem. Cycle PD JUL-AUG PY 2002 VL 16 IS 3 AR 1035 DI 10.1029/2001GB001444 PG 15 WC Environmental Sciences; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Geology; Meteorology & Atmospheric Sciences GA 611GU UT WOS:000179008700010 ER PT J AU Novak, RE Mumma, MJ DiSanti, MA Dello Russo, N Magee-Sauer, K AF Novak, RE Mumma, MJ DiSanti, MA Dello Russo, N Magee-Sauer, K TI Mapping of ozone and water in the atmosphere of Mars near the 1997 aphelion SO ICARUS LA English DT Article DE Mars atmosphere; composition; infrared observations; spectroscopy; photochemistry ID THERMAL EMISSION SPECTROMETER; O1 HALE-BOPP; MARTIAN ATMOSPHERE; O-2 DAYGLOW; VAPOR; PHOTOCHEMISTRY; ABUNDANCE; BEHAVIOR; SEASON; CLOUDS AB We present absolute abundances and latitudinal variations of ozone and water in the atmosphere of Mars (luring its late northern spring (L-s = 67.3degrees) shortly before aphelion. Long-slit maps of the a(1)Delta(g) state of molecular oxygen (O-2) and HDO, an isotopic form of water, were acquired on UT January 21.6 1997 using a high-resolution infrared spectrometer (CSHELL) at the NASA Infrared Telescope Facility. O-2(a(1)Deltag) is produced by ozone photolysis, and the ensuing dayglow emission at 1.27 mum is used as a tracer for ozone. Retrieved vertical column densities for ozone above similar to20 km ranged between 1.5 and 2.8 mum-atm at mid- to low latitudes (30degreesS-60degreesN) and decreased outside that region. A significant decrease in ozone density is seen near 30degreesN (close to the subsolar latitude of 23.5degreesN). The rotational temperatures retrieved from O-2(a-X) emissions show a mean of 172 +/- 2.5 K, confirming that the sensed ozone lies in the middle atmosphere (similar to24 km). The nu(1) fundamental band of HDO near 3.67 Pm was used as a proxy for H2O. The retrieved vertical column abundance of water varies from 3 precipitable microns (pr-mum) at similar to30degreesS to 24 pr-mum at similar to60degreesN. We compare these results with current photochemical models and with measurements obtained by other methods. (C) 2002 Elsevier Science (USA). C1 Iona Coll, Dept Phys, New Rochelle, NY 10801 USA. NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. Rowan Coll, Dept Chem & Phys, Glassboro, NJ 08028 USA. RP Novak, RE (reprint author), Iona Coll, Dept Phys, New Rochelle, NY 10801 USA. RI mumma, michael/I-2764-2013; Magee-Sauer, Karen/K-6061-2015; Dello Russo, Neil/G-2727-2015 OI Magee-Sauer, Karen/0000-0002-4979-9875; Dello Russo, Neil/0000-0002-8379-7304 NR 45 TC 45 Z9 46 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 JUL PY 2002 VL 158 IS 1 BP 14 EP 23 DI 10.1006/icar.2002.6863 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 574WM UT WOS:000176912600002 ER PT J AU Bell, JF Farrand, WH Johnson, JR Morris, RV AF Bell, JF Farrand, WH Johnson, JR Morris, RV TI Low abundance materials at the Mars Pathfinder landing site: An investigation using spectral mixture analysis and related techniques SO ICARUS LA English DT Article DE Mars, surface; surfaces, planets; mineralogy; image processing ID MARTIAN SURFACE; IMAGER; IDENTIFICATION; MINERALS; PYROXENE; CAMERA AB Recalibrated and geometrically registered multispectral images from the Imager for Mars Pathfinder (IMP) were analyzed using Spectral Mixture Analysis (SMA) and related techniques. SMA models a multispectral image scene as a linear combination of endmember spectra, and anomalous materials which do not fit the model are detected as model residuals. While most of the IMP data studied here are modeled generally well using "Bright Dust," "Gray Rock," and "Shade" image endmembers, additional anomalous materials were detected through careful analysis of root mean square (RMS) error images resulting from SMA. For example, analysis of SMA fraction and RMS images indicates spectral differences within a previously monolithologic Dark Soil class. A type of Dark Soil that has high fractional abundances in rock fraction images (Gray Rock Soil) was identified. Other anomalous materials identified included a previously noted "Black Rock" lithology, a class of possibly indurated, compacted, or partially cemented soils ("Intermediate Soil"), and a unit referred to as "Anomalous Patches" on at least one rock. The Black Rock lithology has a strong 900-1000-nm absorption, and modeling of the derived image endmembers using a laboratory reference endmember modeling (REM) approach produced best-fit model spectra that are most consistent with the presence of high-Ca pyroxenes and/or olivine, crystalline ferric oxide minerals, or mixtures of these materials as important components of the Black Rock endmember. More unique mineralogic identifications could not be obtained using our initial REM analyses. Both Intermediate Soil and Anomalous Patches units exhibit a relatively narrow 860-950-nm absorption that is consistent with the presence of either low-Ca pyroxenes or a cementing crystalline ferric oxide mineral. (C) 2002 Elsevier Science (USA). C1 Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. Space Sci Inst, Boulder, CO USA. US Geol Survey, Astrogeol Team, Flagstaff, AZ 86001 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Bell, JF (reprint author), Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. RI Johnson, Jeffrey/F-3972-2015 NR 41 TC 16 Z9 16 U1 0 U2 0 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD JUL PY 2002 VL 158 IS 1 BP 56 EP 71 DI 10.1006/icar.2002.6865 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 574WM UT WOS:000176912600005 ER PT J AU Bauer, JM Roush, TL Geballe, TR Meech, KJ Owen, TC Vacca, WD Rayner, JT Jim, KTC AF Bauer, JM Roush, TL Geballe, TR Meech, KJ Owen, TC Vacca, WD Rayner, JT Jim, KTC TI The near infrared spectrum of Miranda - Evidence of crystalline water ice SO ICARUS LA English DT Article DE uranian satellite; outer Solar System; water ID HUBBLE-SPACE-TELESCOPE; CARBON-DIOXIDE ICE; CENTAUR 1997 CU26; URANIAN SATELLITES; ABSORPTION-SPECTRUM; SURFACE-COMPOSITION; OPTICAL-PROPERTIES; 2060 CHIRON; H2O ICE; MU M AB A spectrum from 1.2 to 2.5 mum of Uranus' small satellite Miranda obtained in June 1999 reveals strong water-ice signatures. It confirms the existence of a 2.0-mum water feature previously detected on Miranda and shows a strong second broad 1.5-mum water-ice absorption feature. The spectra also reveal a weak absorption band at 1.65 mum that is indicative of crystalline water ice. Reflectance models which combine the new spectra with new photometry indicate that the spectra are characteristic of a mostly water-ice surface, with a large fraction of carbonaceous or silicate contaminates, and the possible presence of ammonia hydrate, as implied by an apparent weak feature near 2.2 mum. The possible presence of other volatiles is also investigated. (C) 2002 Elsevier Science (USA). C1 Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. NASA, Ames Res Ctr, Div Space Sci, Planetary Syst Branch, Moffett Field, CA 94035 USA. Gemini 8 Meter Telescope Project, Hilo, HI 96720 USA. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. RP Univ Hawaii, Inst Astron, 2680 Woodlawn Dr, Honolulu, HI 96822 USA. EM bauer@ifa.hawaii.edu NR 66 TC 53 Z9 54 U1 1 U2 5 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 EI 1090-2643 J9 ICARUS JI Icarus PD JUL PY 2002 VL 158 IS 1 BP 178 EP 190 DI 10.1006/icar.2002.6876 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 574WM UT WOS:000176912600011 ER PT J AU Cuzzi, JN French, RG Dones, L AF Cuzzi, JN French, RG Dones, L TI HST multicolor (255-1042 nm) photometry of Saturn's main rings - I: Radial profiles, phase and opening angle variations, and regional spectra SO ICARUS LA English DT Article ID PARTICLE EROSION MECHANISMS; HUBBLE-SPACE-TELESCOPE; PLANETARY RINGS; B-RING; MU-M; BALLISTIC TRANSPORT; ABSORPTION-BAND; STANDARD STARS; SATELLITES; EUROPA AB The main rings of Saturn were observed with the Planetary Camera of the WFPC2 instrument on the Hubble Space Telescope (HST) from September 1996 to December 2000 as the ring opening angle to Earth and Sun increased from 4degrees to 24degrees, with a spread of phase angles between 0.3degrees and 6degrees at each opening angle. The rings were routinely observed in the five HST wideband UBVRI filters (F336W, F439W, F555W, F675W, and F814W) and occasionally in the F255W, F785LP, and F1042M filters. The emphasis in this series of papers will be on radial color (implying compositional) variations. In this first paper we describe the analysis technique and calibration procedure, note revisions in a previously published Voyager ring color data analysis, and present new results based on over 100 HST images. In the 300-600 run spectral range where the rings are red, the 555/336-nm ratio increases by about 14% as the phase angle increases from 0.3degrees to 6degrees. This effect, never reported previously for the rings, is significantly larger than the phase reddening which characterizes other icy objects, primarily because of the redness of the rings. However, there is no discernible tendency for color to vary with ring opening angle at a given phase angle, and there is no phase variation of color where the spectrum is flat. We infer from this combination of facts that multiple intraparticle scattering, either in a regolith or between facts of an unusually rough surface, is important in these geometries, but that multiple interparticle scattering in a vertically extended layer is not. Voyager color ratios at a phase angle of 14degrees are compatible with this trend, but calibration uncertainties prevent their use in quantitative modeling. Overall ring average spectra are compatible with those of earlier work within calibration uncertainties, but ring spectra vary noticeably with region. We refine and subdivide the regions previously defined by others. The variation seen between radial profiles of ratios between different wavelengths suggests the presence of multiple compositional components with different radial distributions. We present new radial profiles of far-UV color ratio (F336W/F255W) showing substantial global variations having a different radial structure than seen between 555 and 336 nm. We constrain radial variation in the strength of a putative 850-nm spectral feature to be at the percent level or less. There seem to be real variations in the shape of regional ring spectra between 800 and 1000 nm. (C) 2002 Elsevier Science (USA). C1 NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. Wellesley Coll, Dept Astron, Wellesley, MA 02481 USA. SW Res Inst, Boulder, CO 80302 USA. RP NASA, Ames Res Ctr, Div Space Sci, Mail Stop 245-3, Moffett Field, CA 94035 USA. EM jcuzzi@mail.arc.nasa.gov NR 89 TC 33 Z9 33 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 EI 1090-2643 J9 ICARUS JI Icarus PD JUL PY 2002 VL 158 IS 1 BP 199 EP 223 DI 10.1006/icar.2002.6851 PG 25 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 574WM UT WOS:000176912600013 ER PT J AU Poulet, F Cuzzi, JN French, RG Dones, L AF Poulet, F Cuzzi, JN French, RG Dones, L TI A study of Saturn's ring phase curves from HST observations SO ICARUS LA English DT Article DE planetary rings; Saturn-phase curve; opposition effect-shadow-hiding, coherent backscattering ID BIDIRECTIONAL REFLECTANCE SPECTROSCOPY; PARTICLE-SIZE DISTRIBUTIONS; RADIATIVE-TRANSFER; COHERENT BACKSCATTER; ATMOSPHERELESS BODIES; PLANETARY REGOLITHS; RADIO OCCULTATION; OPPOSITION SURGE; SURFACE; SATELLITES AB Solar phase curves between 0.3degrees and 6.0degrees and color ratios at wavelengths, lambda= 0.336 mum and lambda = 0.555 mum for Saturn's rings are presented using recent Hubble Space Telescope observations. We test the hypothesis that the phase reddening of the rings is less due to collective properties of the ring particles than to the individual properties of the ring particles. We use a modified Drossart model, the Hapke model, and the Shkuratov model to model reddening by either intraparticle shadow-hiding on fractal and normal surfaces, multiple scattering, or some combination. The modified Drossart model (including only shadowing) failed to reproduce the data. The Hapke model gives fair fits, except for the color ratios. A detailed study of the opposition effect suggests that coherent backscattering is the principal cause of the opposition surge at very small phase angles. The shape of the phase curve and color ratios of each main ring regions are accurately represented by the Shkuratov model, which includes both a shadow-hiding effect and coherent backscatter enhancement. Our analysis demonstrates that in terms of particle roughness, the C ring particles are comparable to the Moon, but the Cassini division and especially the A and B ring particles are significantly rougher, suggesting lumpy particles such as often seen in models. Another conspicuous difference between ring regions is in the effective size d of regolith grains (d similar to lambda, for the C ring particles, d similar to 1-10 mum for the other rings). (C) 2002 Elsevier Science (USA). C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Wellesley Coll, Dept Astron, Wellesley, MA 02481 USA. SW Res Inst, Boulder, CO 80302 USA. RP Poulet, F (reprint author), NASA, Ames Res Ctr, MS 245-3, Moffett Field, CA 94035 USA. NR 53 TC 29 Z9 29 U1 0 U2 1 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD JUL PY 2002 VL 158 IS 1 BP 224 EP 248 DI 10.1006/icar.2002.6852 PG 25 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 574WM UT WOS:000176912600014 ER PT J AU Simon-Miller, AA Gierasch, PJ Beebe, RF Conrath, B Flasar, FM Achterberg, RK AF Simon-Miller, AA Gierasch, PJ Beebe, RF Conrath, B Flasar, FM Achterberg, RK CA Cassini CIRS Team TI New observational results concerning Jupiter's Great Red Spot SO ICARUS LA English DT Article DE Jupiter; atmosphere; atmospheres; dynamics; atmospheres; evolution; atmospheres; structure ID VOYAGER IRIS MEASUREMENTS; PARA-HYDROGEN; ATMOSPHERE; STABILITY; DYNAMICS; REGION AB The changing size and aspect ratio of the Great Red Spot from 1880 to 2000 are reviewed, indicating that the length of the system has decreased significantly over the last 100 years and continues to decrease at present at a rate of 0.19 degrees per year. Voyager IRIS maps of para hydrogen fraction and potential temperature over the system are presented, showing the internal structure and surrounding areas at pressures from 100 to 500 mbars. In these maps, the GRS appears as a cold temperature anomaly and a low para fraction anomaly. Vertical structure analyses and wind velocity measurements are presented from data acquired by the Galileo spacecraft in 1996 and 2000, respectively. The vertical structure data suggest a very thick, white, cloud deck with a top near 800 100 mbars and an extended, blue-absorbing, optically thick haze up to about 200 mbars with a thin stratospheric haze above it. The wind field shows a substantial increase in the maximum tangential velocity from 150 to 190 m s(-1) over the Galileo time period. The vertical structure analyses from Galileo data and the wind and temperature fields from Voyager data all show evidence of a tilt to the Great Red Spot at the cloud deck from north to south and more subtly from east to west. The data support the hypothesis of the GRS as a tilted "pancake" with temporal variability to the tilt. (C) 2002 Elsevier Science (USA). C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Cornell Univ, Ithaca, NY 14853 USA. New Mexico State Univ, Dept 4500, Las Cruces, NM 88003 USA. SSAI, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Simon-Miller, AA (reprint author), NASA, Goddard Space Flight Ctr, Mailstop 693-0, Greenbelt, MD 20771 USA. RI Flasar, F Michael/C-8509-2012; Simon, Amy/C-8020-2012 OI Simon, Amy/0000-0003-4641-6186 NR 37 TC 36 Z9 36 U1 0 U2 4 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD JUL PY 2002 VL 158 IS 1 BP 249 EP 266 DI 10.1006/icar.2002.6867 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 574WM UT WOS:000176912600015 ER PT J AU Pravec, P Sarounova, L Hicks, MD Rabinowitz, DL Wolf, M Scheirich, P Krugly, YN AF Pravec, P Sarounova, L Hicks, MD Rabinowitz, DL Wolf, M Scheirich, P Krugly, YN TI Two periods of 1999 HF1 - Another binary NEA candidate SO ICARUS LA English DT Article DE asteroids; binary-photometry ID EARTH ASTEROIDS; LIGHTCURVES AB Photometric observations of 1999 HF1 reveal that its lightcurve has two components of low amplitudes (0.10-0.12 mag) and different periods (2.3191 and 14.02 h). It is likely another binary near-Earth asteroid; its lower limit on the secondary-to-primary-diameter ratio is approximate to 0.2, the radius of the mutual orbit is (2.0 +/- 0.3) x the effective primary diameter, the primary's bulk density is >2.0 g/cm(3), and it belongs to the E/M/P taxonomic class. (C) 2002 Elsevier Science (USA). C1 Acad Sci Czech Republ, Inst Astron, CZ-25165 Ondrejov, Czech Republic. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Yale Univ, Dept Phys, New Haven, CT 06520 USA. Charles Univ, Astron Inst, CZ-18000 Prague, Czech Republic. Kharkiv Natl Univ, Astron Observ, UA-61022 Kharkov, Ukraine. RP Pravec, P (reprint author), Acad Sci Czech Republ, Inst Astron, CZ-25165 Ondrejov, Czech Republic. RI Pravec, Petr/G-9037-2014; Scheirich, Peter/H-4331-2014 OI Scheirich, Peter/0000-0001-8518-9532 NR 17 TC 9 Z9 9 U1 0 U2 1 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD JUL PY 2002 VL 158 IS 1 BP 276 EP 280 DI 10.1006/icar.2002.6845 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 574WM UT WOS:000176912600018 ER PT J AU Vilnrotter, VA Srinivasan, M AF Vilnrotter, VA Srinivasan, M TI Adaptive detector arrays for optical communications receivers SO IEEE TRANSACTIONS ON COMMUNICATIONS LA English DT Article DE optical array detection; optical detection in turbulence; photon-counting arrays AB An optimal adaptive array receiver for use in ground-based optical communications is investigated. Kolmogorov phase screen simulations are used to generate realistic focal-plane distributions of the received optical fields in the presence of turbulence. The array detection concept reduces interference from background radiation by effectively assigning higher confidence levels at each instant of time to those detector elements that contain significant signal energy and suppressing those that do not. A simpler suboptimum structure that replaces the continuous weighting of the optimal receiver by a hard decision over each detector element is also described. It is shown that, for photon counting receivers observing Poisson distributed signals, performance improvements of, up to 5 dB can be obtained over conventional single-detector photon counting receivers when observing turbulent optical fields in high background environments. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Vilnrotter, VA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 TC 30 Z9 30 U1 0 U2 3 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 JUL PY 2002 VL 50 IS 7 BP 1091 EP 1097 DI 10.1109/TCOMM.2002.800813 PG 7 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA 579YG UT WOS:000177206100010 ER PT J AU Diner, DJ Verstraete, MM Martonchik, JV AF Diner, DJ Verstraete, MM Martonchik, JV TI Foreword to special section on MISR SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Editorial Material C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Commiss European Communities, Joint Res Ctr, Inst Environm & Sustainabil, I-21020 Ispra, Italy. RP Diner, DJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. OI Verstraete, Michel/0000-0003-0968-8721 NR 0 TC 3 Z9 3 U1 0 U2 0 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 JUL PY 2002 VL 40 IS 7 BP 1447 EP 1448 DI 10.1109/TGRS.2002.802777 PG 2 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 584PP UT WOS:000177476800001 ER PT J AU Diner, DJ Beckert, JC Bothwell, GW Rodriguez, JI AF Diner, DJ Beckert, JC Bothwell, GW Rodriguez, JI TI Performance of the MISR instrument during its first 20 months in earth orbit SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE Earth; imaging; multiangle; remote sensing AB The Multi-angle Imaging SpectroRadiometer, one of five science instruments aboard NASA's Terra spacecraft, was launched into earth orbit in December 1999. Acquisition of earth imagery began in February 2000, and the quality of the data is excellent. Overall, MISR has been performing superbly, though the instrument exhibits several idiosyncrasies, some of which were anticipated prior to launch. Details regarding the in-flight performance of the instrument system are presented. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Diner, DJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 13 TC 79 Z9 82 U1 0 U2 6 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 JUL PY 2002 VL 40 IS 7 BP 1449 EP 1466 DI 10.1109/TGRS.2002.801584 PG 18 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 584PP UT WOS:000177476800002 ER PT J AU Bothwell, GW Hansen, EG Vargo, RE Miller, KC AF Bothwell, GW Hansen, EG Vargo, RE Miller, KC TI The Multi-angle Imaging SpectroRadiometer science data system, its products, tools, and performance SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE algorithms; data processing; data products; ground system ID INSTRUMENT DESCRIPTION; MISR AB Ground processing of data from the Multi-angle Imaging SpectroRadiometer (MISR) instrument, part of NASA's Earth Observing System (EOS), exploits new and unique science algorithms not previously used operationally. A range of data products from Level 1 through Level 3 is being produced. Because of MISR's unprecedented design, extensive prototyping was required from a relatively early stage. The data throughput is large, necessitating an innovative software design approach that maximizes performance. The systematic science processing software was developed at the Jet Propulsion Laboratory (JPL), with data processing occurring at the NASA Langley Research Center using the EOS Core System (ECS), a collaborative arrangement that works well. With the availability of actual mission data following launch on the Terra spacecraft in December 1999, MISR's computational needs have become better known, and many improvements have been made to both the science software and the production system to achieve a successful overall data processing capability. This paper provides information about MISR data for the science user, and describes the nature and scope of implementation and operations activities. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bothwell, GW (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 TC 29 Z9 31 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 JUL PY 2002 VL 40 IS 7 BP 1467 EP 1476 DI 10.1109/TGRS.2002.801152 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 584PP UT WOS:000177476800003 ER PT J AU Bruegge, CJ Chrien, NL Ando, RR Diner, DJ Abdou, WA Helmlinger, MC Pilorz, SH Thome, KJ AF Bruegge, CJ Chrien, NL Ando, RR Diner, DJ Abdou, WA Helmlinger, MC Pilorz, SH Thome, KJ TI Early validation of the multi-angle Imaging SpectroRadiometer (MISR) radiometric scale SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE calibration; Multi-angle Imaging SpectroRadiometer (MISR); radiometry ID INSTRUMENT DESCRIPTION; CALIBRATION AB The Multi-angle Imaging SpectroRadiometer (MISR) instrument consists of nine cameras, four spectral bands each, and an on-board calibrator (OBC). Experiments using the latter allow camera radiometric coefficients to be updated bimonthly. Data products are thus calibrated to a stable radiometric scale, even in the presence of instrument response changes. The camera, band, and pixel-relative calibrations are accurately determined using the OBC. Conversely, as the OBC itself is subject to response degradation, MISR also conducts annual field vicarious calibration (VC) campaigns. The first of these, conducted June 2000 at a desert site in Nevada, has been used to establish the present absolute radiometric scale. Validation of this radiometric scale, using AirMISR, shows consistency to within 4%. Following these studies, however, it was determined that MISR radiometry is subject to scene-dependent effects due to ghosting that, for the Nevada test sites, reduces the apparent radiance by 3%. Correction for this effect is required in order to avoid radiometric errors over sites that do not exhibit the same background contrast. Additional studies are in progress, with plans to correct for scene-contrast effects in future Level 1B1 processing. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Arizona, Tucson, AZ 85721 USA. RP Bruegge, CJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Thome, Kurtis/D-7251-2012 NR 17 TC 54 Z9 54 U1 1 U2 6 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 JUL PY 2002 VL 40 IS 7 BP 1477 EP 1492 DI 10.1109/TGRS.2002.801583 PG 16 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 584PP UT WOS:000177476800004 ER PT J AU Chrien, NL Bruegge, CJ Ando, RR AF Chrien, NL Bruegge, CJ Ando, RR TI Multi-angle Imaging SpectroRadiometer (MISR) on-board calibrator (OBC) in-flight performance studies SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE calibration; photodiodes; radiometry AB The Multi-angle Imaging SpectroRadiometer (MISR) consists of nine cameras pointing from nadir to an extreme of 70.5degrees in the view angle. It is a pushbroom imager with four spectral bands per camera. Instrument specifications call for each camera to be calibrated to an absolute uncertainty of 3% and to within 1% relative to the other cameras. To accomplish this, the MISR instrument utilizes an on-board calibrator (OBC) to provide updates to the instrument gain coefficients on a bimonthly basis (i.e., once every two months). Spectralon diffuse panels are used in the OBC to provide a uniform target for the nine MISR cameras to view. The radiometric scale of the OBC is established through the use of photodiodes. The stability of the MISR OBC system and its in-flight calibration are discussed in this paper. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Chrien, NL (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 9 TC 16 Z9 16 U1 0 U2 5 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 JUL PY 2002 VL 40 IS 7 BP 1493 EP 1499 DI 10.1109/TGRS.2002.801156 PG 7 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 584PP UT WOS:000177476800005 ER PT J AU Abdou, WA Bruegge, CJ Helmlinger, MC Conel, JE Pilorz, SH Ledeboer, W Gaitley, BJ Thome, KJ AF Abdou, WA Bruegge, CJ Helmlinger, MC Conel, JE Pilorz, SH Ledeboer, W Gaitley, BJ Thome, KJ TI Vicarious calibration experiment in support of the Multi-angle Imaging SpectroRadiometer SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE calibration; MISR radiometric calibration; vicarious calibration ID INSTRUMENT DESCRIPTION; MISR; AIRMISR AB On June 11, 2000, the first vicarious calibration experiment in support of the Multi-angle Imaging SpectroRadiometer (MISR) was conducted. The purpose of this experiment was to acquire in situ measurements of surface and atmospheric conditions over a bright, uniform area. These data were then used to compute top-of-atmosphere (TOA) radiances, which were correlated with the camera digital number output, to determine the in-flight radiometric response of the on-orbit sensor. The Lunar Lake Playa, NV, was the primary target instrumented by the Jet Propulsion Laboratory for this experiment. The airborne MISR simulator (AirMISR) on board a NASA ER-2 acquired simultaneous observations over Lunar Lake. The in situ estimations of top-of-atmosphere radiances and AirMISR measurements at a 20-km altitude were in good agreement with each other and differed by 9% from MISR measurements. The difference has been corrected by adjusting the gain coefficients used in MISR standard product generation. Data acquired simultaneously by other sensors, such as Landsat, the Terra Moderate-Resolution Imaging SpectroRadiometer (MODIS), and the Airborne Visible and Infrared Imaging Spectrometer (AVIRIS), were used to validate this correction. Because of this experiment, MISR radiances are 9% higher than the values based on the on-board calibration. Semiannual field campaigns are planned for the future in order to detect any systematic trends in sensor calibration. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Arizona, Ctr Opt Sci, Tucson, AZ 85721 USA. RP Abdou, WA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Thome, Kurtis/D-7251-2012 NR 16 TC 24 Z9 24 U1 1 U2 7 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 JUL PY 2002 VL 40 IS 7 BP 1500 EP 1511 DI 10.1109/TGRS.2002.801582 PG 12 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 584PP UT WOS:000177476800006 ER PT J AU Jovanovic, VM Bull, MA Smyth, MM Zong, J AF Jovanovic, VM Bull, MA Smyth, MM Zong, J TI MISR in-flight camera geometric model calibration and georectification performance SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE calibration; georectification; mapping; photogrammetry AB In order to facilitate a unique georectification approach implemented for Multi-angle Imaging SpectroRadiometer (MISR) data, specific calibration datasets need to be derived during flight. In the case of the spaceborne MISR instrument, with its unique configuration of nine fixed pushbroom cameras, continuous and autonomous coregistration and geolocation of image data are required prior to the application of scientific retrieval algorithms. In-flight-generated calibration datasets are required to a) assure accuracy, b) reduce processing load, and c) support autonomous aspects of the processing algorithm. This paper describes the in-flight geometric calibration approach with the focus on the first year of activities and the georectification performance achieved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Jovanovic, VM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 13 TC 32 Z9 32 U1 0 U2 0 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 JUL PY 2002 VL 40 IS 7 BP 1512 EP 1519 DI 10.1109/TGRS.2002.801143 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 584PP UT WOS:000177476800007 ER PT J AU Martonchik, JV Diner, DJ Crean, KA Bull, MA AF Martonchik, JV Diner, DJ Crean, KA Bull, MA TI Regional aerosol retrieval results from MISR SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE aerosol; algorithms; remote sensing ID OPTICAL DEPTH; LAND; OCEAN; SENSITIVITY AB Examples of aerosol retrieval results, derived from the Multi-angle Imaging SpectroRadiometer (MISR) on the Earth Observation Science (EOS) Terra platform, are shown and the performance of the retrieval algorithms are discussed, following the first 18 months of operational data processing. A number of algorithm modifications were implemented, based on an analysis of aerosol retrieval results during this period, and these changes are described. Two cloud-screening algorithms, the angle-to-angle smoothness and angle-to-angle correlation tests, which were used in the preprocessing phase of the analyses are also described. The aerosol retrieval examples cover a wide variety of conditions, both over land and water. Particular aerosol types include dust clouds, forest fire and volcanic plumes, and localized dense haze. Finally, some ideas are discussed for additional improvement of the MISR aerosol data product, based on the experience gained in analyzing multiangle data and the associated geophysical products. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Martonchik, JV (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 16 TC 130 Z9 134 U1 1 U2 16 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 JUL PY 2002 VL 40 IS 7 BP 1520 EP 1531 DI 10.1109/TGRS.2002.801142 PG 12 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 584PP UT WOS:000177476800008 ER PT J AU Moroney, C Davies, R Muller, JP AF Moroney, C Davies, R Muller, JP TI Operational retrieval of cloud-top heights using MISR data SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE cloud-top heights; Multi-angle Imaging SpectroRadiometer (MISR); multiangle; pattern recognition; stereo-matching; winds ID MOTION; ALTITUDE AB Due to its unique nine-angle configuration, the Multi-angle Imaging SpectroRadiometer (MISR) can retrieve cloud parameters such as cloud-motion vectors and cloud-top heights using a purely geometrical technique that involves locating the same cloud features at different viewing angles. The geometrical nature of this technique means that the retrievals are relatively insensitive to the absolute instrument calibration. Fast stereo-matching algorithms have been developed to perform this image matching automatically on an operational basis. Preliminary results are shown of the operational retrievals together with comparisons against other data. Cloud-top height is generally obtained on a 1.1-km grid with an accuracy of +/-562 in, even over snow and ice. The limitations of the technique, resulting at times in height blunders, noisy retrievals, and discrete effects of wind correction, are discussed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. UCL, Dept Geomat Engn, London WC1E 6BT, England. RP Moroney, C (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Catherine.M.Moroney@jpl.nasa.gov RI Davies, Roger/D-4296-2009; OI Davies, Roger/0000-0002-2991-0409; Muller, Jan-Peter/0000-0002-5077-3736 NR 9 TC 101 Z9 102 U1 0 U2 10 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD JUL PY 2002 VL 40 IS 7 BP 1532 EP 1540 DI 10.1109/TGRS.2002.801150 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 584PP UT WOS:000177476800009 ER PT J AU Moroney, C Horvath, A Davies, R AF Moroney, C Horvath, A Davies, R TI Use of stereo-matching to coregister multiangle data from MISR SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE coregistration; Multi-angle Imaging SpectroRadiometer (MISR); multiangle; stereo-matching; winds ID CLOUD AB The pattern-matching algorithms originally developed for Multi-angle Imaging SpectroRadiometer (MISR) (flying on the Earth Observing System (EOS) Terra platform) cloud retrieval have also proven useful in independently providing quality assurance of the coregistration of multiangle measurements with the nadir view. Two new techniques developed to test the coregistration are described in this paper along with results of the misregistration detection on both historical and current data. No ground-control points are strictly necessary for these calculations-just simultaneous clear-sky land imagery for three cameras and knowledge of the terrain altitude. The difficulty of registration increases with the obliquity of the view angle, so our emphasis is on coregistering to the nadir view. This paper also provides proxy validation of the stereo-matching algorithms for clear-sky land scenes. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Arizona, Inst Atmospher Phys, Tucson, AZ 85721 USA. RP Moroney, C (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Horvath, Akos/A-2453-2008; Davies, Roger/D-4296-2009 OI Horvath, Akos/0000-0002-5860-2368; Davies, Roger/0000-0002-2991-0409 NR 8 TC 15 Z9 16 U1 0 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 JUL PY 2002 VL 40 IS 7 BP 1541 EP 1546 DI 10.1109/TGRS.2002.801146 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 584PP UT WOS:000177476800010 ER PT J AU Muller, JP Mandanayake, A Moroney, C Davies, R Diner, DJ Paradise, S AF Muller, JP Mandanayake, A Moroney, C Davies, R Diner, DJ Paradise, S TI MISR stereoscopic image matchers: Techniques and results SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE cloud-top height; Multi-angle Imaging SpectroRadiometer (MISR); operational applications of photogrammetry; stereo matching ID CLOUD-TOP HEIGHTS; WIND FIELDS; RETRIEVAL; MOTION AB The Multi-angle Imaging SpectroRadiometer (MISR) instrument, launched in December 1999 on the NASA EOS Terra Satellite, produces images in the red band at 275-m resolution, over a swath width of 360 kin, for the nine camera angles 70.5degrees, 60degrees, 45.6degrees, and 26.1degrees forward, nadir and 26.1degrees, 45.6degrees, 60degrees, and 70.5degrees aft (hereafter, referred to as Df, Cf, Bf, Af, An, Aa, Ba, Ca, and Da, respectively). A set of accurate and fast algorithms was developed for automated stereo matching of cloud features to obtain cloud-top height and motion over the nominal six-year lifetime of the mission. Accuracy and speed requirements necessitated the use of a combination of area-based and feature-based stereo-matchers with only pixel-level acuity. Feature-based techniques are used for cloud motion retrieval with the off-nadir MISR camera views, and the motion is then used to provide a correction to the disparities used to measure cloud-top heights which are derived from the innermost three cameras. Intercomparison with a previously developed "superstereo" matcher shows that the results are very comparable in accuracy with much greater coverage and at ten times the speed. Intercomparison of feature-based and area-based techniques shows that the feature-based techniques are comparable in accuracy at a factor of eight times the speed. An assessment of the accuracy of the area-based matcher for cloud-free scenes demonstrates the accuracy and completeness of the stereo-matcher. This trade-off has resulted in the loss of a reliable quality metric to predict accuracy and a slightly high blunder rate. Examples are shown of the application of the MISR stereo-matchers on several difficult scenes which demonstrate the efficacy of the matching approach. C1 UCL, Dept Geomat Engn, London WC1E 6BT, England. 3Q Technol, Unit 6, Harefield UB9 6JA, Middx, England. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Muller, JP (reprint author), UCL, Dept Geomat Engn, Mortimer St, London WC1E 6BT, England. EM jpmuller@ge.ucl.ac.uk RI Davies, Roger/D-4296-2009; OI Davies, Roger/0000-0002-2991-0409; Muller, Jan-Peter/0000-0002-5077-3736 NR 21 TC 81 Z9 83 U1 1 U2 6 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD JUL PY 2002 VL 40 IS 7 BP 1547 EP 1559 DI 10.1109/TGRS.2002.801160 PG 13 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 584PP UT WOS:000177476800011 ER PT J AU Pinty, B Widlowski, JL Gobron, N Verstraete, MM Diner, DJ AF Pinty, B Widlowski, JL Gobron, N Verstraete, MM Diner, DJ TI Uniqueness of multiangular measurements - Part I: An indicator of subpixel surface heterogeneity from MISR SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE k parameter; MISR; RPV model; surface heterogeneity ID BIDIRECTIONAL REFLECTANCE; MODEL; SCATTERING; ALBEDO; LIGHT; VEGETATION; RETRIEVAL; LAND AB The recent availability of quasi-simultaneous multispectral and multidirectional measurements from space, as provided by the Multi-angle Imaging SpectroRadiometer (MISR) on board the Terra platform, offers new and unique opportunities to document the anisotropy of land surfaces at critical solar wavelengths. This paper presents simple physical principles supporting the interpretation of the anisotropy of spectral radiances exiting terrestrial surfaces in terms of a signature of surface heterogeneity. The shape of the anisotropy function is represented with two model parameter values which may be mapped and interpreted in their own right. The value of one of these parameters also permits identifying geophysical conditions where the surface heterogeneity becomes significant and where three-dimensional (3-D) radiation transfer effects have to be explicitly accounted for. This paper documents these findings on the basis of results from a number of 3-D radiation transfer model simulations. The latter are used to perform an extensive sensitivity study which includes issues related to the scale of investigation. A preliminary validation of these results, conducted with a dataset collected by the AirMISR instrument over the Konza prairie, is also discussed. C1 Commiss European Communities, Joint Res Ctr, Inst Environm & Sustainabil, I-21020 Ispra, VA, Italy. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Pinty, B (reprint author), Commiss European Communities, Joint Res Ctr, Inst Environm & Sustainabil, I-21020 Ispra, VA, Italy. OI Verstraete, Michel/0000-0003-0968-8721 NR 30 TC 84 Z9 87 U1 0 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 JUL PY 2002 VL 40 IS 7 BP 1560 EP 1573 DI 10.1109/TGRS.2002.801148 PG 14 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 584PP UT WOS:000177476800012 ER PT J AU Gobron, N Pinty, B Verstraete, MM Widlowski, JL Diner, DJ AF Gobron, N Pinty, B Verstraete, MM Widlowski, JL Diner, DJ TI Uniqueness of multiangular measurements - Part II: Joint retrieval of vegetation structure and photosynthetic activity from MISR SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE FAPAR; MISR; surface heterogeneity; VEGAS; vegetation index ID SURFACE ALBEDO RETRIEVAL; AEROSOL; REFLECTANCE; LAND; METEOSAT; INDEXES AB The Multi-angle Imaging SpectroRadiometer (MISR) instrument on board the Terra platform offers the capability of acquiring reflectance data on any earth target in four spectral bands, from nine different directions, in at most seven minutes, at a spatial resolution adequate for the monitoring of the status of terrestrial surfaces. This paper describes the implementation of a physical and mathematical approach to design a simple two-dimensional algorithm dedicated to the interpretation of data collected by this instrument. One dimension fully exploits the spectral information in the blue, red and near infrared bands while the other dimension capitalizes on the multiangular capability of MISR to assess the anisotropic behavior of terrestrial surfaces with respect to solar radiation. The spectral information is derived following an approach proposed for single angle instruments, such as the MEdium Resolution Imaging Spectrometer (MERIS), the Global Imager (GLI), the Sea-viewing Wide Field-of-view Sensor (SeaWIFS) and VEGETATION. The access to simultaneous multiangular observations from MISR allows extending this approach. This strategy delivers an estimate of the Fraction of Absorbed Photosynthetically Active Radiation (FAPAR), which pertains to vegetation photosynthetic activity and is a measure of the presence and density of vegetation. As shown in Part 1, the angular shape of the reflectance is strongly related to the architecture of the vegetation and, under some favorable conditions, permits an assessment of surface heterogeneity. The proposed VEGetation Activity and Structure (VEGAS) algorithm for MISR therefore delivers two axes of information representing a) FAPAR and b) vegetation structure at MISR subpixel resolution. Its application should improve the present knowledge of vegetation characteristics at regional and global scales. C1 Commiss European Communities, Joint Res Ctr, Inst Environm & Sustainabil, I-21020 Ispra, VA, Italy. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Gobron, N (reprint author), Commiss European Communities, Joint Res Ctr, Inst Environm & Sustainabil, I-21020 Ispra, VA, Italy. EM bernard.pinty@jrc.it OI Verstraete, Michel/0000-0003-0968-8721 NR 21 TC 51 Z9 53 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD JUL PY 2002 VL 40 IS 7 BP 1574 EP 1592 DI 10.1109/TGRS.2002.801147 PG 19 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 584PP UT WOS:000177476800013 ER PT J AU Jin, YF Gao, F Schaaf, CB Li, XW Strahler, AH Bruegge, CJ Martonchik, JV AF Jin, YF Gao, F Schaaf, CB Li, XW Strahler, AH Bruegge, CJ Martonchik, JV TI Improving MODIS surface BRDF/Albedo retrieval with MISR multiangle observations SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE Albedo; Earth Observing System (EOS); Moderate Resolution Imaging Spectroradiometer (MODIS); Multiangle Imaging SpectroRadiometer (MISR); remote sensing; surface bidirectional reflectance ID REFLECTANCE DISTRIBUTION FUNCTION; IMAGING SPECTRORADIOMETER MODIS; BIDIRECTIONAL REFLECTANCE; EOS-MODIS; LAND SURFACES; BRDF MODELS; ALBEDO; ANISOTROPY; VALIDATION; INVERSION AB We explore a synergistic approach to use the complementary angular samplings from the Multi-angle Imaging SpectroRadiometer (MISR) and Moderate Resolution Imaging Spectroradiometer (MODIS) to improve MODIS surface bidirectional reflectance distribution function (BRDF) and albedo retrieval. Preliminary case studies show that MODIS and MISR surface bidirectional reflectance factors (BRFs) are generally comparable in the green, red, and near infrared. An information index is introduced to characterize the information content of directional samplings, and it is found that MISR angular observations can bring additional information to the MODIS retrieval, especially when the MISR observations are close to the principal plane. We use the BRDF parameters derived from the MISR surface BRFs as a priori information and derive a posteriori estimates of surface BRDF parameters with the MODIS observations. Results show that adding MISR angular samplings can reduce the relative BRF prediction error by up to 10% in the red and green, compared to the retrievals from MODIS-only observations which are close to the cross-principal plane. C1 Boston Univ, Dept Geog, Boston, MA 02215 USA. Beijing Normal Univ, Res Ctr Remote Sensing, Beijing 100875, Peoples R China. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Jin, YF (reprint author), Boston Univ, Dept Geog, Boston, MA 02215 USA. RI Gao, Feng/F-3944-2010 NR 38 TC 38 Z9 45 U1 0 U2 12 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 JUL PY 2002 VL 40 IS 7 BP 1593 EP 1604 DI 10.1109/TGRS.2002.801145 PG 12 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 584PP UT WOS:000177476800014 ER PT J AU Braverman, A Di Girolamo, L AF Braverman, A Di Girolamo, L TI MISR global data products: A new approach SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE clustering algorithms; data compression; entropy-constrained vector quantization; Level 3 products; massive datasets AB This paper describes a new type of global, gridded product being created by the Multi-angle Imaging SpectroRadiometer (MISR) team. The product is a compressed version, or summary, of MISR geophysical data products on a 11 monthly global grid. Data belonging to each grid cell are summarized by a multivariate histogram. The numbers, sizes, and shapes of the histogram bins vary among cells, and they adapt to the shape of the data in high-dimensional space. Also, bin representatives are means rather than midpoints. These modifications allow data to be summarized parsimoniously and with lower error than is possible using customary, simple, descriptive statistics. The method is demonstrated by compressing test MISR aerosol data, and performance is assessed by comparing computations using compressed data with those using the original. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Illinois, Dept Atmospher Sci, Urbana, IL 61801 USA. RP Braverman, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 5 TC 4 Z9 4 U1 0 U2 2 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 JUL PY 2002 VL 40 IS 7 BP 1626 EP 1636 DI 10.1109/TGRS.2002.801159 PG 11 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 584PP UT WOS:000177476800017 ER PT J AU Martonchik, JV Pinty, B Verstraete, MM AF Martonchik, JV Pinty, B Verstraete, MM TI Note on "an improved model of surface BRDF-atmospheric coupled radiation" SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE algorithms; radiative transfer ID RETRIEVAL; REFLECTANCE; ALBEDO; MISR; LAND AB A recent paper compared approximate radiative transfer results for top-of-atmosphere (TOA) radiance, using various algorithms published in the literature. We show that one of the algorithms was used incorrectly, resulting in its poor performance as stated in that paper. Correct usage produces results with errors typically less than 3%, which compares favorably to the other tested algorithms. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Commiss European Communities, Joint Res Ctr, Inst Environm & Sustainabil, I-21020 Ispra, VA, Italy. RP Martonchik, JV (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. OI Verstraete, Michel/0000-0003-0968-8721 NR 8 TC 16 Z9 17 U1 0 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 JUL PY 2002 VL 40 IS 7 BP 1637 EP 1639 DI 10.1109/TGRS.2002.802505 PG 3 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 584PP UT WOS:000177476800018 ER PT J AU Kulikov, IK AF Kulikov, IK TI Harmonic oscillator in external fields: Applications to trapped bosons and fermions SO INTERNATIONAL JOURNAL OF THEORETICAL PHYSICS LA English DT Article DE harmonic oscillator; gravitational field; trapped atoms ID BOSE-EINSTEIN CONDENSATION; GASES AB Properties of harmonic oscillator in external fields are studied. The formalism developed is applied to a harmonic oscillator in a nonhomogeneous gravitational field. Partition functions and thermodynamic potentials for trapped Bose and Fermi gases are found. Thermodynamics of trapped Bosons and Fermions in external fields is discussed. C1 CALTECH, Jet Prop Lab, Quantum Comp Technol Grp, Pasadena, CA 91109 USA. RP Kulikov, IK (reprint author), CALTECH, Jet Prop Lab, Quantum Comp Technol Grp, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 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 0020-7748 J9 INT J THEOR PHYS JI Int. J. Theor. Phys. PD JUL PY 2002 VL 41 IS 7 BP 1281 EP 1289 AR UNSP 0020-7748/02/0700-1281/0 DI 10.1023/A:1019650932160 PG 9 WC Physics, Multidisciplinary SC Physics GA 582JN UT WOS:000177347300003 ER PT J AU Bednarcyk, BA Arnold, SM AF Bednarcyk, BA Arnold, SM TI Fully coupled micro/macro deformation, damage, and failure prediction for SiC/Ti-15-3 laminates SO JOURNAL OF AEROSPACE ENGINEERING LA English DT Article DE laminates; deformation; damage; failure; prediction ID MICROMECHANICAL ANALYSIS; MATRIX COMPOSITES; MODEL; CELLS AB The deformation, failure, and low-cycle fatigue life of SCS-6/Ti-15-3 composites are predicted using a coupled deformation and damage approach in the context of the analytical generalized method of cells (GMC) micromechanics model. The local effects of inelastic deformation, fiber breakage, fiber-matrix interfacial debonding, and fatigue damage are included as submodels that operate on the microscale for the individual composite phases. For the laminate analysis, lamination theory is employed as the global or structural scale model, while GMC is embedded to operate on the mesoscale to simulate the behavior of the composite material within each laminate layer. While the analysis approach is quite complex and multifaceted, it is shown through comparison with experimental data to be quite accurate and realistic, while remaining extremely efficient. C1 Univ Virginia, Dept Civil Engn, Charlottesville, VA 22903 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Bednarcyk, BA (reprint author), Univ Virginia, Dept Civil Engn, Thornton Hall, Charlottesville, VA 22903 USA. NR 29 TC 7 Z9 7 U1 1 U2 1 PU ASCE-AMER SOC CIVIL ENGINEERS PI RESTON PA 1801 ALEXANDER BELL DR, RESTON, VA 20191-4400 USA SN 0893-1321 J9 J AEROSPACE ENG JI J. Aerosp. Eng. PD JUL PY 2002 VL 15 IS 3 BP 74 EP 83 DI 10.1061/(ASCE)0893-1321(2002)15:3(74) PG 10 WC Engineering, Aerospace; Engineering, Civil SC Engineering GA 566YL UT WOS:000176455800002 ER PT J AU Roberts, GD Revilock, DM Binienda, WK Nie, WZ Mackenzie, SB Todd, KB AF Roberts, GD Revilock, DM Binienda, WK Nie, WZ Mackenzie, SB Todd, KB TI Impact testing and analysis of composites for aircraft engine fan cases SO JOURNAL OF AEROSPACE ENGINEERING LA English DT Article DE impact tests; containment; composite structures; engines; fans AB The fan case in a jet engine is a heavy structure because of its size and because of the requirement that it contain a blade released during engine operation. Composite materials offer the potential for reducing the weight of the case. Efficient design, test, and analysis methods are needed to efficiently evaluate the large number of potential composite materials and design concepts. The type of damage expected in a composite case under blade-out conditions was evaluated using a subscale test in which a glass/epoxy composite half-ring target was impacted with a wedge-shaped titanium projectile. Fiber shearing occurred near points of contact between the projectile and target. Delamination and tearing occurred on a larger scale. These damage modes were reproduced in a simpler test in which flat glass/epoxy composites were impacted with a blunt cylindrical projectile. A surface layer of ceramic eliminated fiber shear fracture but did not reduce delamination. Tests on 3D woven carbon/epoxy composites indicated that transverse reinforcement is effective in reducing delamination. A 91-cm (36 in.) diameter full-ring subcomponent was proposed for larger scale testing of these and other composite concepts. Explicit, transient, finite-element analyses indicated that a full-ring test is needed to simulate complete impact dynamics, but simpler tests using smaller ring sections are adequate when the evaluation of initial impact damage is the primary concern. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Univ Akron, Dept Civil Engn, Akron, OH 44325 USA. St Gobain Performance Plast, Ravenna, OH 44266 USA. RP Roberts, GD (reprint author), NASA, Glenn Res Ctr, MS 49-1,21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 8 TC 12 Z9 13 U1 2 U2 8 PU ASCE-AMER SOC CIVIL ENGINEERS PI RESTON PA 1801 ALEXANDER BELL DR, RESTON, VA 20191-4400 USA SN 0893-1321 J9 J AEROSPACE ENG JI J. Aerosp. Eng. PD JUL PY 2002 VL 15 IS 3 BP 104 EP 110 DI 10.1061/(ASCE)0893-1321(2002)15:3(104) PG 7 WC Engineering, Aerospace; Engineering, Civil SC Engineering GA 566YL UT WOS:000176455800005 ER PT J AU Harris, CE Starnes, JH Shuart, MJ AF Harris, CE Starnes, JH Shuart, MJ TI Design and manufacturing of aerospace composite structures, state-of-the-art assessment SO JOURNAL OF AIRCRAFT LA English DT Article ID WALLED CARBON NANOTUBES; YOUNGS MODULUS; STRENGTH AB The results of an assessment of the state of the art in the design and manufacturing of large composite structures are described. The focus of the assessment is on the use of polymeric matrix composite materials for large air-frame structural components, such as those in commercial and military aircraft and space transportation vehicles. Applications of composite materials for large commercial transport aircraft, general aviation aircraft, rotorcraft, military aircraft, and uninhabited rocket launch vehicles are reviewed. The results of the assessment of the state of the art include a summary of lessons learned, examples of current practice, and an assessment of advanced technologies under development. The results of the assessment conclude with an evaluation of the future technology challenges and advancements associated with applications of composite materials to the primary structures of commercial transport aircraft and advanced space transportation vehicles. These future technologies include breakthroughs in materials and process methods, next generation design tools, and nondestructive examination methods. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Harris, CE (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 37 TC 22 Z9 24 U1 1 U2 18 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD JUL-AUG PY 2002 VL 39 IS 4 BP 545 EP 560 DI 10.2514/2.2992 PG 16 WC Engineering, Aerospace SC Engineering GA 582AU UT WOS:000177328200003 ER PT J AU Rossow, VJ AF Rossow, VJ TI Reduction of uncertainties in prediction of wake-vortex locations SO JOURNAL OF AIRCRAFT LA English DT Article; Proceedings Paper CT AIAA 18th Applied Aerodynamics Conference CY AUG 14-17, 2000 CL DENVER, COLORADO SP Amer Inst Aeronaut & Astronaut ID INSTABILITY; PAIR AB Lift-generated vortex wakes of subsonic transport aircraft are known to pose a rolling-moment hazard to in-trail following aircraft. Hazardous wake encounters are now avoided by maintaining in-trail separation distances that are larger than needed for other operational considerations. To increase airport capacity, considerable effort has been devoted to the development of techniques and procedures by which vortex wakes can be accurately located as a function of time, so that following aircraft can avoid them with less in-trail spacings. To improve the accuracy with which vortex wakes can be located, a study of the uncertainties associated with the determination of the time-dependent location of vortex wakes and on ways to reduce the uncertainties are reported. It is found that it is beneficial to reduce the uncertainties as much as possible by application of technology currently available for aircraft guidance and for measurement of wind velocity along the flight corridor by aircraft. It appears, however, that the growth in, and spreading of, the size of the hazardous region surrounding wake vortices is so rapid that it currently prevents sizeable increases in the capacity of runways at airports as they now operate. Therefore, if airport capacity is to be significantly increased, it is concluded that it will be necessary to also introduce some other system of sequential flight corridors such as the ones illustrated here, for example, to provide more lateral and vertical distance between the flight paths of aircraft so that wake encounters are avoided. 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 210-10, Moffett Field, CA 94035 USA. NR 30 TC 8 Z9 8 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD JUL-AUG PY 2002 VL 39 IS 4 BP 587 EP 596 DI 10.2514/2.2996 PG 10 WC Engineering, Aerospace SC Engineering GA 582AU UT WOS:000177328200007 ER PT J AU Gorton, SA Berry, JD Hodges, WT Reis, DG AF Gorton, SA Berry, JD Hodges, WT Reis, DG TI Rotor wake study near the horizontal tail of a T-tail configuration SO JOURNAL OF AIRCRAFT LA English DT Article AB Development of advanced rotorcraft configurations has highlighted a need-for high-quality experimental data to support the development of robust and accurate analytical design tools. To provide high-quality experimental data, a test program was conducted in the NASA Langley Research Center 14- by 22-Foot Subsonic Tunnel to measure the flow near the empennage of a 15% scale powered helicopter model with an operating tail fan and a T-tail configuration. Three-component velocity profiles were measured forward of the horizontal tail for four advance ratios using laser velocimetry to evaluate the effect of the rotor wake impingement on the horizontal tail angle of attack. These velocity data indicate the horizontal tail can experience unsteady angle-of-attack variations of over 30 deg due to the rotor wake influence. The horizontal tail is most affected by the rotor wake at and above advance ratios of 0.10. C1 NASA, Langley Res Ctr, Flow Phys & Control Branch, Hampton, VA 23681 USA. USA, Aviat & Missile Command, Dynam & Aerodynam Branch, Aeromech Div,Aviat Engn Directorate, Redstone Arsenal, AL 35898 USA. USA, Aviat & Missile Command, Joint Res Program Off, Aeroflightdynam Directorate, Hampton, VA 23681 USA. RP Gorton, SA (reprint author), NASA, Langley Res Ctr, Flow Phys & Control Branch, Mail Stop 170, Hampton, VA 23681 USA. NR 48 TC 3 Z9 3 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD JUL-AUG PY 2002 VL 39 IS 4 BP 645 EP 653 DI 10.2514/2.2977 PG 9 WC Engineering, Aerospace SC Engineering GA 582AU UT WOS:000177328200015 ER PT J AU Shepherd, JM Pierce, H Negri, AJ AF Shepherd, JM Pierce, H Negri, AJ TI Rainfall modification by major urban areas: Observations from spaceborne rain radar on the TRMM satellite SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID ST-LOUIS; HEAT-ISLAND; PRECIPITATION; SENSITIVITY; VALIDATION AB Data from the Tropical Rainfall Measuring Mission (TRMM) satellite's precipitation radar (PR) were employed to identify warm-season rainfall (1998-2000) patterns around Atlanta, Georgia; Montgomery, Alabama; Nashville, Tennessee; and San Antonio, Waco, and Dallas, Texas. Results reveal an average increase of about 28% in monthly rainfall rates within 30-60 km downwind of the metropolis, with a modest increase of 5.6% over the metropolis. Portions of the downwind area exhibit increases as high as 51%. The percentage changes are relative to an upwind control area. It was also found that maximum rainfall rates in the downwind impact area exceeded the mean value in the upwind control area by 48%-116%. The maximum value was generally found at an average distance of 39 km from the edge of the urban center or 64 km from the center of the city. Results are consistent with the Metropolitan Meteorological Experiment (METROMEX) studies of St. Louis, Missouri, almost two decades ago and with more recent studies near Atlanta. The study establishes the possibility of utilizing satellite-based rainfall estimates for examining rainfall modification by urban areas on global scales and over longer time periods. Such research has implications for weather forecasting, urban planning, water resource management, and understanding human impact on the environment and climate. C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Sci Syst & Applicat Inc, Lanham, MD USA. RP Shepherd, JM (reprint author), NASA, Goddard Space Flight Ctr, Atmospheres Lab, Code 912-0, Greenbelt, MD 20771 USA. NR 43 TC 198 Z9 230 U1 1 U2 56 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 JUL PY 2002 VL 41 IS 7 BP 689 EP 701 DI 10.1175/1520-0450(2002)041<0689:RMBMUA>2.0.CO;2 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 559KM UT WOS:000176025400001 ER PT J AU Tian, L Heymsfield, GM Srivastava, RC AF Tian, L Heymsfield, GM Srivastava, RC TI Measurement of attenuation with airborne and ground-based radar in convective storms over land and its microphysical implications SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID TRMM PRECIPITATION RADAR; RAIN AB Observations by the airborne X-band Doppler radar (known as EDOP) and the NCAR S-band polarimetric (S-Pol) radar from two field experiments are used to evaluate the surface reference technique (SRT) for measuring the path-integrated attenuation (PIA) and to study attenuation in deep convective storms. The EDOP, flying at an altitude of 20 km, uses a nadir beam and a forward-pointing beam. It is found that over land the surface scattering cross section is highly variable at nadir incidence but is relatively stable at forward incidence. It is concluded that measurement by the forward beam provides a viable technique for measuring PIA using the SRT. Vertical profiles of peak attenuation coefficient are derived in two deep convective storms by the dual-wavelength method. Using the measured Doppler velocity, the reflectivities at the two wavelengths, the differential reflectivity, and the estimated attenuation coefficients, it is shown that supercooled drops and (dry) ice particles probably coexisted above the melting level in regions of updraft and that water-coated partially melted ice particles probably contributed to high attenuation below the melting level. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21201 USA. Univ Chicago, Chicago, IL 60637 USA. RP Tian, L (reprint author), NASA, Goddard Space Flight Ctr, Code 912, Greenbelt, MD 20771 USA. NR 22 TC 9 Z9 9 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 JUL PY 2002 VL 41 IS 7 BP 716 EP 733 DI 10.1175/1520-0450(2002)041<0716:MOAWAA>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 559KM UT WOS:000176025400003 ER PT J AU Grose, AME Smith, EA Chung, HS Ou, ML Sohn, BJ Turk, FJ AF Grose, AME Smith, EA Chung, HS Ou, ML Sohn, BJ Turk, FJ TI Possibilities and limitations for quantitative precipitation forecasts using nowcasting methods with infrared geosynchronous satellite imagery SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID SENSOR MICROWAVE IMAGER; TROPICAL CYCLONE; RAIN RATE; CLOUD; WINDS; OPERATIONS; RETRIEVAL; PROJECT; RADAR AB A rainfall nowcasting system is developed that identifies locations of raining clouds on consecutive infrared geosynchronous satellite images while predicting the movement of the rain cells for up to 10 h using cloud-motion-based winds. As part of the analysis, the strengths and weaknesses of various kinds of cloud wind filtering schemes and both steady and nonsteady storm advection techniques as forecast operators for quantitative precipitation forecasting are evaluated. The first part of the study addresses the development of a probability matching method (PMM) between histograms of equivalent blackbody temperatures (EBBTs) and Special Sensor Microwave Imager (SSM/I)- derived rain rates (RRs), which enables estimating RRs from instantaneous infrared imagery and allows for RR forecasts from the predicted EBBT fields. The second part of the study addresses the development and testing of the nowcasting system built upon the PMM capability and analyzes its success according to various skill score metrics. Key processes involved in the nowcasting system include the retrieved cloud-motion wind field, the filtered cloud-motion wind field, and the forecasting of a future rain field by storm advection and EBBT tendencies. These processes allow for the short-term forecasting of cloud and rain locations and of rain intensity, using PMM-based RRs from different datasets of infrared Geostationary Meteorological Satellite (GMS) and Geostationary Operational Environmental Satellite (GOES) imagery. For this study, three convective rain sequences from the Caribbean basin, the Amazon basin, and the Korean peninsula are analyzed. The final part of the study addresses the decay of forecast accuracy with time (i.e., the point at which the asymptotic limit on forecast skill is reached). This analysis indicates that the nowcasting system can produce useful rainfall forecast information out to approximately 6 h. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Florida State Univ, Dept Meteorol, Tallahassee, FL 32306 USA. Korean Meteorol Adm, Meteorol Res Inst, Seoul, South Korea. Seoul Natl Univ, Sch Earth & Environm Sci, Seoul, South Korea. USN, Res Lab, Marine Meteorol Div, Monterey, CA USA. RP Smith, EA (reprint author), NASA, Goddard Space Flight Ctr, Code 912-1, Greenbelt, MD 20771 USA. NR 42 TC 12 Z9 15 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD JUL PY 2002 VL 41 IS 7 BP 763 EP 785 DI 10.1175/1520-0450(2002)041<0763:PALFQP>2.0.CO;2 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 559KM UT WOS:000176025400007 ER PT J AU Casperson, JD Bell, LD Atwater, HA AF Casperson, JD Bell, LD Atwater, HA TI Materials issues for layered tunnel barrier structures SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID GATE DIELECTRICS GD2O3; BAND OFFSETS; ULTRATHIN SIO2; FILMS; SILICON; DEPOSITION; DEVICES; MEMORY; Y2O3 AB Layered dielectric tunnel barriers are expected to greatly increase the program/erase speeds of nonvolatile floating gate memory devices and could allow both nanosecond program/erase times as well as archival data storage. We have correlated dielectric constants and band offsets with respect to silicon in order to help identify possible materials from which to construct these devices. A numerical model has been developed to assess potential layered tunnel barrier materials and structures suitable for integration into silicon electronics. With this model, we explore the relative dominance of Fowler-Nordheim tunneling and thermionic emission and we present simulated I-V curves for some candidate materials. (C) 2002 American Institute of Physics. C1 CALTECH, Thomas J Watson Lab Appl Phys, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Casperson, JD (reprint author), CALTECH, Thomas J Watson Lab Appl Phys, Pasadena, CA 91125 USA. NR 27 TC 64 Z9 64 U1 0 U2 11 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUL 1 PY 2002 VL 92 IS 1 BP 261 EP 267 DI 10.1063/1.1479747 PG 7 WC Physics, Applied SC Physics GA 564LA UT WOS:000176314800043 ER PT J AU Yamauchi, K Hales, NW Robinson, SM Niehoff, ML Ramesh, V Pellis, NR Kulkarni, AD AF Yamauchi, K Hales, NW Robinson, SM Niehoff, ML Ramesh, V Pellis, NR Kulkarni, AD TI Dietary nucleotides prevent decrease in cellular immunity in ground-based microgravity analog SO JOURNAL OF APPLIED PHYSIOLOGY LA English DT Article DE nutrition; microgravity; mice ID DELAYED-HYPERSENSITIVITY; DURATION MISSIONS; MICE; SPACEFLIGHT; RESTRICTION; FLIGHT AB Microgravity and stress of spaceflights result in immune dysfunction. The role of nutrition, especially nucleotide supplementation, has become an area of intensive research and significant interest in immunomodulation for maintenance of cellular immune responses. The studies presented here evaluate the plausibility of administering nucleotides to obviate immune dysfunction in an Earth-based in vivo analog of microgravity as studied in anti-orthostatic tail suspension (AOS) of mice. Mice were divided into three housing groups: group, isolation, and AOS. Mice were fed either control chow diet (CD), or RNA-, adenine-, or uracil-supplemented CD for the 1-wk duration of the experiments. In AOS mice, supplemental nucleotides significantly increased in vivo lymph node proliferation and ex vivo lymphoproliferation response to alloantigen and mitogens, respectively, and interleukin-2 and interferon-gamma production. A lower corticosterone level was observed in uracil-supplemented CD compared with CD. These results suggest that exogenous nucleotide supplementation, especially uracil, of normal diet is beneficial in the maintenance and restoration of the immune response during the microgravity analog conditions. C1 Univ Texas, Hlth Sci Ctr, Dept Surg, Houston, TX 77030 USA. NASA, Lyndon B Johnson Space Ctr, Cellular Biotechnol, Houston, TX 77058 USA. St Louis Univ, Sch Med, Dept Surg, St Louis, MO 63104 USA. RP Kulkarni, AD (reprint author), Univ Texas, Hlth Sci Ctr, Dept Surg, 6431 Fannin St,MSB Suite 4-164, Houston, TX 77030 USA. NR 23 TC 22 Z9 25 U1 1 U2 2 PU AMER PHYSIOLOGICAL SOC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 8750-7587 J9 J APPL PHYSIOL JI J. Appl. Physiol. PD JUL PY 2002 VL 93 IS 1 BP 161 EP 166 DI 10.1152/japplphysiol.01084.2001 PG 6 WC Physiology; Sport Sciences SC Physiology; Sport Sciences GA 563JV UT WOS:000176253300021 PM 12070200 ER PT J AU Tanelli, S Im, E Durden, SL Facheris, L Giuli, D AF Tanelli, S Im, E Durden, SL Facheris, L Giuli, D TI The effects of nonuniform beam filling on vertical rainfall velocity measurements with a spaceborne Doppler radar SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID MEASURING MISSION TRMM; PRECIPITATION RADAR AB Information on the global distribution of vertical velocity of precipitating particles is needed in estimating latent heat fluxes, and therefore in the general study of energy transportation phenomena in the atmosphere. Such information is not currently available, but it can potentially be obtained by a spaceborne Doppler precipitation radar. In this paper, the expected performance for this type of Doppler radar for measuring vertical rainfall velocity is investigated. Although the high relative speed of the instrument with respect to the rainfall droplets contributes significantly to the spreading of the Doppler spectrum, accurate estimates of the average vertical velocity can be obtained when the rainfall intensity does not vary significantly within the resolution volume of the instrument. Such a result can be inferred through theoretical calculations and is confirmed by analyzing the Doppler spectra simulated using data gathered by the NASA/Jet Propulsion Laboratory (JPL) airborne rain radar in the Kwajelein Experiment (KWAJEX) and in the Tropical Ocean Global Atmosphere Coupled Ocean-Atmosphere Response Experiment (TOGA COARE). When significant variation in rain rate is present within the radar's field of view in the along-track direction, the Doppler shift caused by the radial component of the satellite motion is weighted differently in different portions of resolution cell. The error caused by this nonuniform beam-filling (NUBF) effect may dominate any other contribution. Under this condition, the shape, average value, and width of the Doppler spectrum do not directly correlate with the vertical velocity of the precipitating particles. Further analysis of the reflectivity pattern is required in order to correct for the NUBF-induced error. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Florence, Dipartimento Elettron & Telecomunicaz, Florence, Italy. RP Im, E (reprint author), CALTECH, Jet Prop Lab, Mail Stop 300-227,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 25 TC 35 Z9 35 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD JUL PY 2002 VL 19 IS 7 BP 1019 EP 1034 DI 10.1175/1520-0426(2002)019<1019:TEONBF>2.0.CO;2 PG 16 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 564KB UT WOS:000176312600003 ER PT J AU Mariotti, A Struglia, MV Zeng, N Lau, KM AF Mariotti, A Struglia, MV Zeng, N Lau, KM TI The hydrological cycle in the Mediterranean region and implications for the water budget of the Mediterranean Sea SO JOURNAL OF CLIMATE LA English DT Article ID NORTH-ATLANTIC OSCILLATION; GLOBAL PRECIPITATION; ATMOSPHERIC MOISTURE; REANALYSIS PROJECT; GAUGE OBSERVATIONS; PART II; CLIMATE; MODEL; VARIABILITY; NCEP/NCAR AB The hydrological cycle in the Mediterranean region is analyzed focusing on climatology and interannual to interdecadal variability, in particular long-term changes related to the well-established North Atlantic Oscillation (NAO) teleconnection. Recent atmospheric reanalyses and observational datasets are used: precipitation, evaporation, and moisture flux from 50 yr of NCEP's and 15 yr of ECMWF's reanalyses; precipitation from the Climate Prediction Center Merged Analysis of Precipitation (CMAP) and the East Anglia University Climate Research Unit (CRU) datasets; and evaporation from the University of Wisconsin-Milwaukee (UWM) Comprehensive Ocean-Atmosphere Data Set (COADS). A budget analysis is performed to study contributions to the freshwater flux into the Mediterranean Sea, including atmospheric as well as river discharge inputs. The total river discharge is derived using historical time series from Mediterranean Hydrological Cycle Observing System (MED-HYCOS) and Global Runoff Data Center (GRDC) archives. Mediterranean-averaged precipitation during the period 1979-93 has an annual mean ranging among datasets from 331 to 477 mm yr 21, with a seasonal cycle amplitude of similar to700 mm yr(-1). Evaporation is estimated in the range of 934-1176 mm yr(-1) with a seasonal cycle amplitude of similar to1000 mm yr(-1). The excess of evaporation over precipitation gives an annual mean Mediterranean Sea water loss ranging among datasets approximately from 500 to 700 mm yr(-1). The annual mean river discharge is 100 mm yr(-1), somewhat smaller than previous estimates using similar approaches. Water loss to the atmosphere and riverine inputs combined lead to an estimated Mediterranean freshwater deficit of about 500 mm yr(-1), consistent with most oceanographically based estimates of the water flux from the Atlantic Ocean at the Gibraltar Strait. On interannual to interdecadal timescales, during the period 1948-98, the Mediterranean atmospheric winter water deficit is positively correlated with the NAO and has been increasing due to the long-term positive anomalies of the NAO since the early 1970s. Precipitation, which is also significantly correlated with the NAO, appears to be mostly responsible for this since no significant correlation is found for evaporation. Over the 50-yr period the Mediterranean atmospheric water deficit increased by about 24% in the winter season, and by 9% annually. Given the pattern of the NAO-related precipitation anomalies, this change is likely to have occurred primarily north of 35degreesN. The results presented here suggest that in response to the changes in the freshwater flux significant variations in the characteristics of Mediterranean waters and the Gibraltar flux may also have occurred during this period, mostly driven by the influence of the NAO. C1 Univ Maryland, Earth Syst Sci Interdisciplinary Ctr, College Pk, MD 20742 USA. Univ Maryland, Dept Meteorol, College Pk, MD 20742 USA. ENEA, Climate Sect, Rome, Italy. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Univ Maryland, Earth Syst Sci Interdisciplinary Ctr, 2207 Comp & Space Sci Bldg, College Pk, MD 20742 USA. EM annarita.mariotti@casaccia.enea.it RI Zeng, Ning/A-3130-2008; Lau, William /E-1510-2012 OI Zeng, Ning/0000-0002-7489-7629; Lau, William /0000-0002-3587-3691 NR 43 TC 184 Z9 187 U1 0 U2 18 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 EI 1520-0442 J9 J CLIMATE JI J. Clim. PD JUL PY 2002 VL 15 IS 13 BP 1674 EP 1690 DI 10.1175/1520-0442(2002)015<1674:THCITM>2.0.CO;2 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 564QR UT WOS:000176325500011 ER PT J AU Tessler, A Dambach, ML Oplinger, DW AF Tessler, A Dambach, ML Oplinger, DW TI Efficient adaptive mesh refinement modeling of adhesive joints SO JOURNAL OF COMPOSITES TECHNOLOGY & RESEARCH LA English DT Article DE adhesive joints; error estimation; adaptive mesh refinement; smoothing finite element; penalty method ID ELEMENT STRESS RECOVERY; ERROR ESTIMATION; VARIATIONAL METHOD; LAP JOINTS; EQUILIBRIUM AB The smoothing element analysis for stress recovery and error estimation is applied to facilitate adaptive finite element solutions of adhesively bonded structures. The formulation is based on the minimization of a penalized discrete least-squares variational principle leading up to the recovery of C-1-continuous stress fields from discrete, Gauss-point finite element stresses. The smoothed distributions are then used as reference solutions in a posteriori error estimators. Adaptive mesh refinements are performed to predict the linearly elastic response of uniformed and tapered double splice adhesively bonded joints. Key aspects pertaining to specific smoothing strategies, adaptive refinement solutions, and detailed stress distributions are discussed. Consistent comparisons are also presented with Oplinger's one-dimensional adhesive lap joint analysis. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. GM Corp, Detroit, MI 48202 USA. FAA, Ctr Tech, Atlantic City Int Airport, Atlantic City, NJ 08405 USA. RP Tessler, A (reprint author), NASA, Langley Res Ctr, M-S 240, Hampton, VA 23681 USA. RI Tessler, Alexander/A-4729-2009 NR 22 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC TESTING MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DR, W CONSHOHOCKEN, PA 19428-2959 USA SN 0884-6804 J9 J COMPOS TECH RES JI J. Compos. Technol. Res. PD JUL PY 2002 VL 24 IS 3 BP 152 EP 179 PG 28 WC Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA 577WA UT WOS:000177084500002 ER PT J AU Brenner, M Xu, YS AF Brenner, M Xu, YS TI A factorization method for identification of Volterra systems SO JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS LA English DT Article; Proceedings Paper CT International Symposium on Applied Mathermatics CY AUG, 2000 CL DALIAN UNIV TECHNOL, DALIAN, PEOPLES R CHINA HO DALIAN UNIV TECHNOL ID MEMORY; SERIES AB A factorization method is proposed for identification of Volterra systems of order n and analyses the stability of the systems constructed by this method. An optimization method is also suggested to generate optimal systems which minimize system response energy. (C) 2001 Elsevier Science B.V. All rights reserved. C1 NASA, Dryden Flight Res Ctr, Aerostruct Branch, Edwards AFB, CA 93523 USA. W Virginia Univ, Dept Math, Morgantown, WV 26506 USA. Acad Sinica, Inst Math, Beijing 100080, Peoples R China. RP Brenner, M (reprint author), NASA, Dryden Flight Res Ctr, Aerostruct Branch, MS 4840D-RS, Edwards AFB, CA 93523 USA. NR 24 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0377-0427 J9 J COMPUT APPL MATH JI J. Comput. Appl. Math. PD JUL 1 PY 2002 VL 144 IS 1-2 SI SI BP 105 EP 117 AR PII S0377-0427(01)00553-2 DI 10.1016/S0377-0427(01)00553-2 PG 13 WC Mathematics, Applied SC Mathematics GA 564BX UT WOS:000176295300007 ER PT J AU Wang, ZJ Liu, Y AF Wang, ZJ Liu, Y TI Spectral (finite) volume method for conservation laws on unstructured grids II. Extension to two-dimensional scalar equation SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article DE high order; unstructured grid; spectral volume; 2D conservation laws ID ESSENTIALLY NONOSCILLATORY SCHEMES; SHOCK-WAVE CALCULATIONS; HIGH-ORDER; ELEMENT METHOD; RIEMANN SOLVERS; IMPLEMENTATION; INTERPOLATION; TRIANGLE; DYNAMICS; SYSTEMS AB The framework for constructing a high-order, conservative spectral (finite) volume (SV) method is presented for two-dimensional scalar hyperbolic conservation laws on unstructured triangular grids. Each triangular grid cell forms a spectral volume (SV), and the SV is further subdivided into polygonal control volumes (CVs) to supported high-order data reconstructions. Cell-averaged solutions from these CVs are used to reconstruct a high-order polynomial approximation in the SV. Each CV is then updated independently with a Godunov-type finite volume method and a high-order Runge-Kutta time integration scheme. A universal reconstruction is obtained by partitioning all SVs in a geometrically similar manner. The convergence of the SV method is shown to depend on how a SV is partitioned. A criterion based on the Lebesgue constant has been developed and used successfully to determine the quality of various partitions. Symmetric, stable, and convergent linear, quadratic, and cubic SVs have been obtained, and many different types of partitions have been evaluated. The SV method is tested for both linear and nonlinear model problems with and without discontinuities. (C) 2002 Elsevier Science (USA). C1 Michigan State Univ, E Lansing, MI 48824 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Michigan State Univ, 2328B Engn Bldg, E Lansing, MI 48824 USA. EM zjw@egr.msu.edu; liu@nas.nasa.gov RI Wang, Z.J./A-9628-2010 OI Wang, Z.J./0000-0002-6203-6303 NR 39 TC 99 Z9 103 U1 0 U2 6 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9991 EI 1090-2716 J9 J COMPUT PHYS JI J. Comput. Phys. PD JUL 1 PY 2002 VL 179 IS 2 BP 665 EP 697 DI 10.1006/jcph.2002.7082 PG 33 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 568ME UT WOS:000176545200015 ER PT J AU Croll, A Salk, N Szofran, FR Cobb, SD Volz, MP AF Croll, A Salk, N Szofran, FR Cobb, SD Volz, MP TI Wetting angles and surface tension of Ge1-xSix melts on different substrate materials SO JOURNAL OF CRYSTAL GROWTH LA English DT Article DE solutocapillary convection; surface tension; thermocapillary convection; wetting angle; detached Bridgman technique; floating zone technique; germanium silicon alloys ID OXYGEN PARTIAL-PRESSURE; TEMPERATURE ELECTROSTATIC LEVITATOR; MOLTEN SILICON; THERMOPHYSICAL PROPERTIES; GERMANIUM; SI; WETTABILITY; GROWTH; ALLOYS; DROP AB The wetting angles and surface tension of Ge1-xSix melts (0.0215% below 22 km in the tropics and of 4-12% throughout most of the rest of the stratosphere. In addition, we find a bias with HALOE ozone low relative to SAGE II by 5-20% below 22 km between 40degreesS and 40degreesN. Biases throughout most of the rest of the stratosphere are nearly nonexistent. Finally, our analysis suggests almost no drift in the bias between the data sets is observed over the period of study. In the course of our study, we also determine that the employment of the Wang-Cunnold criteria is still recommended with the V6.00 SAGE II ozone data. Results with the new versions of the data sets show significant improvement over previous versions, particularly in the elimination of midstratospheric biases and the elimination of the previously observed drifts in the biases between the data sets in the lower stratosphere. Since HALOE V19 and V18 ozone are very similar, these changes can likely be attributed to improvements in the SAGE II retrieval. C1 Valparaiso Univ, Dept Phys & Astron, Valparaiso, IN 46383 USA. NASA, Atmospheres Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Hampton Univ, Ctr Atmospher Sci, Hampton, VA 23668 USA. RP Morris, GA (reprint author), Rice Univ, Dept Phys & Astron, MS-61,POB 1892, Houston, TX 77251 USA. EM gmorris@rice.edu; gleason@redwind.gsfc.nasa.gov; james.russell@hamptonu.edu; schom@zephyr.gsfc.nasa.gov RI Gleason, James/E-1421-2012 NR 27 TC 33 Z9 35 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-ATMOS JI J. Geophys. Res.-Atmos. PD JUL PY 2002 VL 107 IS D13 AR 4177 DI 10.1029/2001JD000847 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 610TN UT WOS:000178977100008 ER PT J AU Mote, PW Dunkerton, TJ Wu, D AF Mote, PW Dunkerton, TJ Wu, D TI Kelvin waves in stratospheric temperature observed by the Microwave Limb Sounder SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE Kelvin waves; middle atmosphere; tropics; stratosphere; temperature; Microwave Limb Sounder ID QUASI-BIENNIAL OSCILLATION; TROPICAL UPPER TROPOSPHERE; WATER-VAPOR; EQUATORIAL; DISTURBANCES; UARS AB [1] The three-dimensional (3-D) structure of stratospheric Kelvin waves is revealed using data from the Microwave Limb Sounder for the period July 1992 to April 1993. Four Kelvin wave modes are identified, two for zonal wave number 1 (k = 1) and two for k = 2, using extended empirical orthogonal functions. The 3-D structures of the modes agree with linear theory and satisfy the dispersion relation for Kelvin waves, and with periods ranging from 4.5 to 10 days the modes mostly fall near the boundary between "fast'' and "slow'' Kelvin waves [Canziani et al., 1998]. The analysis also identifies a feature that may correspond with the "pancake structures'' associated with inertial instability. C1 NW Res Associates Inc, Bellevue, WA 98009 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Mote, PW (reprint author), NW Res Associates Inc, POB 3027, Bellevue, WA 98009 USA. EM mote@nwra.com; tim@nwra.com; dwu@mls.jpl.nasa.gov RI Wu, Dong/D-5375-2012 NR 21 TC 16 Z9 16 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL PY 2002 VL 107 IS D14 AR 4218 DI 10.1029/2001JD001056 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 610TQ UT WOS:000178977300011 ER PT J AU Oglesby, RJ Marshall, S Erickson, DJ Roads, JO Robertson, FR AF Oglesby, RJ Marshall, S Erickson, DJ Roads, JO Robertson, FR TI Thresholds in atmosphere-soil moisture interactions: Results from climate model studies SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE soil moisture; climate predictability; climate modeling; hydrology; precipitation ID GENERAL-CIRCULATION MODEL; UNITED-STATES; SNOW COVER; NORTH-AMERICA; VARIABILITY; DROUGHT; PREDICTION; DISTRIBUTIONS; PRECIPITATION; SIMULATIONS AB [1] The potential predictability of the effects of warm season soil moisture anomalies over the central United States has been investigated in a series of general circulation model (GCM) experiments with the National Center for Atmospheric Research (NCAR) Community Climate Model version 3 Land Surface Model (CCM3/LSM). Three different types of experiments have been developed, all starting in either March (representing precursor conditions) or June (conditions at the onset of the warm season): (1) "anomaly'' runs with large, exaggerated initial soil moisture reductions, aimed at evaluating the physical mechanisms by which soil moisture can affect the atmosphere; (2) "predictability'' runs aimed at evaluating whether typical soil moisture initial anomalies (indicative of year-to-year variability) can have a significant effect, and if so, for how long; and (3) "threshold'' runs aimed at evaluating if a soil moisture anomaly must be of a specific size (i.e., a threshold crossed) before a significant impact on the atmosphere is seen. The anomaly runs show a large, long-lasting response in soil moisture as well as surface temperature, sea level pressure, and precipitation; effects persist for at least a year. The predictability runs, on the other hand, show very little impact of the initial soil moisture anomalies on the subsequent evolution of soil moisture and other atmospheric parameters; internal variability is most important, with the initial state of the atmosphere (representing remote effects such as SST anomalies) playing a more secondary role on seasonal and shorter timescales. The threshold runs, devised to help resolve the dichotomy in anomaly and predictability results, suggest that, at least in CCM3/LSM, the vertical profile of soil moisture is the most important factor and that deep soil zone anomalies exert a more powerful, long-lasting effect than do anomalies in the near-surface soil zone. We therefore suggest that soil moisture feedbacks may be more important in explaining interannual to decadal droughts evident in the historic and recent prehistoric records, but less important on monthly to seasonal timescales. C1 NASA, Global Hydrol & Climate Ctr, George C Marshall Space Flight Ctr, Huntsville, AL 35801 USA. Univ N Carolina, Dept Geog & Earth Sci, Charlotte, NC 28223 USA. Oak Ridge Natl Lab, Div Math & Comp Sci, Oak Ridge, TN 37831 USA. Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. RP Oglesby, RJ (reprint author), NASA, Global Hydrol & Climate Ctr, George C Marshall Space Flight Ctr, 320 Sparkman Dr, Huntsville, AL 35801 USA. NR 35 TC 28 Z9 28 U1 0 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0747-7309 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL PY 2002 VL 107 IS D14 AR 4224 DI 10.1029/2001JD001045 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 610TQ UT WOS:000178977300005 ER PT J AU Rinsland, CP Jones, NB Connor, BJ Wood, SW Goldman, A Stephen, TM Murcray, FJ Chiou, LS Zander, R Mahieu, E AF Rinsland, CP Jones, NB Connor, BJ Wood, SW Goldman, A Stephen, TM Murcray, FJ Chiou, LS Zander, R Mahieu, E TI Multiyear infrared solar spectroscopic measurements of HCN, CO, C2H6,and C2H2 tropospheric columns above Lauder, New Zealand (45 degrees S latitude) SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE tropospheric chemistry; biomass burning; tropospheric sources and sinks; pollution ID HYDROGEN-CYANIDE HCN; CARBON-MONOXIDE; SEASONAL-VARIATIONS; WESTERN PACIFIC; ERROR ANALYSIS; KITT PEAK; EMISSIONS; SPECTRA; ETHANE; OZONE AB [1] Near-simultaneous, 0.0035 or 0.007 cm(-1) resolution infrared solar absorption spectra of tropospheric HCN, C2H2, CO, and C2H6 have been recorded from the Network for the Detection of Stratospheric Change station in Lauder, New Zealand (45.04degreesS, 169.68degreesE, 0.37 km altitude). All four molecules were measured on over 350 days with HCN and C2H2 reported for the first time based on a new analysis procedure that significantly increases the effective signal-to-noise of weak tropospheric absorption features in the measured spectra. The CO measurements extend by 2.5 years a database of measurements begun in January 1994 for CO with improved sensitivity in the lower and middle troposphere. The C2H6 measurements lengthen a time series begun in July 1993 with peak sensitivity in the upper troposphere. Retrievals of all four molecules were obtained with an algorithm based on the semiempirical application of the Rodgers optimal estimation technique. Columns are reported for the 0.37- to 12-km-altitude region, approximately the troposphere above the station. The seasonal cycles of all four molecules are asymmetric, with minima in March-June and sharp peaks and increased variability during August-November, which corresponds to the period of maximum biomass burning near the end of the Southern Hemisphere tropical dry season. Except for a possible HCN column decrease, no evidence was found for a statistically significant long-term trend. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Univ Wollongong, Dept Chem, Wollongong, NSW 2522, Australia. Natl Inst Water & Atmospher Res, Lauder, New Zealand. Univ Denver, Dept Phys, Denver, CO 80208 USA. Wyle Labs, Hampton, VA 23666 USA. Univ Liege, Inst Astrophys & Geophys, B-4000 Liege, Belgium. RP Rinsland, CP (reprint author), NASA, Langley Res Ctr, Mail Stop 401A, Hampton, VA 23681 USA. RI Jones, Nicholas/G-5575-2011 OI Jones, Nicholas/0000-0002-0111-2368 NR 50 TC 28 Z9 28 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0747-7309 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL PY 2002 VL 107 IS D14 AR 4185 DI 10.1029/2001JD001150 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 610TQ UT WOS:000178977300044 ER PT J AU Ruzmaikin, A Feynman, J AF Ruzmaikin, A Feynman, J TI Solar influence on a major mode of atmospheric variability SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE North Annular Mode; solar variability; quasi-biennial oscillation ID WINTER STRATOSPHERIC CIRCULATION; QUASI-BIENNIAL OSCILLATION; INTERANNUAL VARIABILITY; NORTHERN-HEMISPHERE; UV VARIABILITY; QBO; TROPOSPHERE; CYCLE; TEMPERATURE; SYSTEM AB [1] We find that the North Annular Mode (NAM) of the wintertime geopotential height anomalies between 10 and 1000 hPa is influenced by solar changes and that the effect is statistically significant. This evidence suggests that a mechanism of solar influence on climate operates through the excitation of this mode. The influence depends on the phase of the quasi-biennial oscillation (QBO). In early winter for the west QBO and late winter for the east QBO the solar changes affect the NAM in both the stratosphere and the troposphere almost equally. The results are compared with earlier studies of the role of the QBO and solar UV changes on near-polar temperatures and geopotential heights. Thus the late winter effect for the west QBO found by Labitzke and van Loon [1988] is clearly evident in the NAM in the stratosphere but does not appear in the troposphere. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ruzmaikin, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 22 TC 29 Z9 29 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0747-7309 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL PY 2002 VL 107 IS D14 AR 4209 DI 10.1029/2001JD001239 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 610TQ UT WOS:000178977300020 ER PT J AU Atkinson, LP Valle-Levinson, A Figueroa, D De Pol-Holz, R Gallardo, VA Schneider, W Blanco, JL Schmidt, M AF Atkinson, LP Valle-Levinson, A Figueroa, D De Pol-Holz, R Gallardo, VA Schneider, W Blanco, JL Schmidt, M TI Oceanographic observations in Chilean coastal waters between Valdivia and Concepcion SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article DE upwelling; wind; water circulation; eddies; central Chile coast ID TOPOGRAPHY AB [1] The physical oceanography of the biologically productive coastal waters of central Chile (36degrees to 40degreesS) is relatively unknown. In December 1998 we made a short exploratory cruise between Valdivia (40degreesS) and Concepcion (37.8degreesS) taking temperature, salinity, oxygen, and current velocity profiles. Coincident sea surface temperature and color measurements were obtained by satellite. The results showed an area dominated by wind-induced coastal upwelling, river runoff, intrusion of offshore eddies, mixing, and heating. Upwelling centers were found over the shelf at three locations: inshore of Mocha Island, off Valdivia, and off Lavapie Point. At these centers, equatorial subsurface water (ESSW) intrudes into the coastal waters, sometimes affecting the surface waters. Since ESSW has characteristically low-oxygen and high-salinity values, it is easily detected. Off Valdivia, runoff imparts stratification, while farther north, solar heating and reduced mixing may facilitate stratification. In some areas, even strong winds would not destroy the stratification imparted by the advection of buoyancy that occurs during the upwelling process. Strong equatorward currents (>1 m s(-1)) in the form of an upwelling jet were found off Lavapie Point. This is also the location of an intruding anticyclone. Elsewhere, currents were mainly northward but highly variable because of intrusions from offshore eddies. The sea surface temperature and ocean color images show a complex field of onshore and offshore intrusions combined with the effects of mixing on chlorophyll concentrations. The residence time of upwelled water on the shelf is estimated to be less than 1 week. C1 Old Dominion Univ, Ctr Coastal Phys Oceanog, Norfolk, VA 23529 USA. Univ Concepcion, Dept Fis Atmosfera & Oceano, Concepcion, Chile. NASA, SeaWIFS Project, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, SAIC, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Atkinson, LP (reprint author), Old Dominion Univ, Ctr Coastal Phys Oceanog, 768 W 52nd St, Norfolk, VA 23529 USA. EM atkinson@ccpo.odu.edu; dfiguero@udec.cl; ricardo@porfc.udec.cl; vagallar@udec.cl; wschnei@udec.cl; mschmidt@gsfc.nasa.gov RI De Pol-Holz, Ricardo/E-3740-2013 OI De Pol-Holz, Ricardo/0000-0002-3281-8232 NR 14 TC 17 Z9 17 U1 0 U2 8 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD JUL PY 2002 VL 107 IS C7 AR 3081 DI 10.1029/2001JC000991 PG 14 WC Oceanography SC Oceanography GA 611AR UT WOS:000178994700005 ER PT J AU Colaprete, A Toon, OB AF Colaprete, A Toon, OB TI Carbon dioxide snow storms during the polar night on Mars SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article DE Mars; clouds; polar clouds; waves; MOLA ID GLOBAL SURVEYOR; CO2 ICE; CAPS; CLOUDS; MODEL; WAVE AB [1] The Mars Orbiter Laser Altimeter detected clouds during the polar night on Mars. While these clouds are associated with topographic features, and are clearly mountain wave clouds as suggest by Pettengill and Ford [2000], we suggest that they differ greatly from terrestrial mountain wave clouds. Uplift generated from flow over the mountains may initiate the clouds on both planets. Terrestrial wave clouds are generally compact features with sharp edges. However, we find that the relatively large mass of condensate on Mars leads to diffuse clouds with snow tails that may extend many kilometers downwind from the mountain and even reach the surface. Both the observations and the simulations suggest substantial carbon dioxide snow precipitation in association with the underlying topography. This precipitation deposits CO2, dust, and water ice to the surface and may lead to propagating geologic features in the Martian polar regions. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Colorado, Atmospher & Space Phys Lab, Program Atmospher & Ocean Sci, Boulder, CO 80309 USA. RP Colaprete, A (reprint author), NASA, Ames Res Ctr, MS 245-3, Moffett Field, CA 94035 USA. NR 23 TC 24 Z9 24 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD JUL PY 2002 VL 107 IS E7 AR 5051 DI 10.1029/2001JE001758 PG 16 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 610UB UT WOS:000178978400006 ER PT J AU Ajello, JM Hansen, DL Beegle, LW Terrell, CA Kanik, I James, GK Makarov, OP AF Ajello, JM Hansen, DL Beegle, LW Terrell, CA Kanik, I James, GK Makarov, OP TI Middle ultraviolet and visible spectrum of SO2 by electron impact SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE ultraviolet; sulfur dioxide; cross sections; Io; spectroscopy; Galileo ID COMPLETE UV SPECTRUM; CROSS-SECTIONS; IOS ATMOSPHERE; EXCITATION; EMISSION; AURORA; SYSTEM; MODEL AB [1] Electron-impact-induced fluorescence spectra of SO2 in the middle ultraviolet and visible wavelength regions (200-600 nm) have been measured in the laboratory using a crossed beam experiment at three electron impact energies. The emission spectra at 8, 18, and 98 eV exhibit a broad and continuous emission region extending from 225 to near 600 nm with a peak emission close to 330 nm. The quasicontinuous SO2 bands arise primarily from direct excitation of SO2. At 18 and 98 eV, simultaneous excitation and dissociation of SO2 produces distinct vibrational bands from SO and from atomic emission lines from S I, S II, O I, and O II that are superimposed on the SO2 electronic transitions. The laboratory spectra were compared to green/violet color ratios obtained at Io by the Galileo Orbiter Solid State Imaging experiment. The laboratory spectra were also applied to the Cassini Imaging Subsystem to determine which filter combinations are particularly sensitive to electron energy, if the atmospheric gas present in the auroral atmosphere is solely or primarily SO2. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ajello, JM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Beegle, Luther/A-6354-2010 NR 22 TC 10 Z9 10 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 JUL PY 2002 VL 107 IS A7 AR 1099 DI 10.1029/2001JA000122 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 610VQ UT WOS:000178982500051 ER PT J AU Cumnock, JA Sharber, JR Heelis, RA Blomberg, LG Germany, GA Spann, JF Coley, WR AF Cumnock, JA Sharber, JR Heelis, RA Blomberg, LG Germany, GA Spann, JF Coley, WR TI Interplanetary magnetic field control of theta aurora development SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE auroral ionosphere; plasma convection; magnetosphere/ionosphere interactions ID POLAR-CAP; TRANSPOLAR ARCS; NORTHWARD; DYNAMICS; PATTERN; MODEL; TIMES; WIND; IMF AB [1] We ascertain the influence of the B-y component of the interplanetary magnetic field (IMF) on theta aurora evolution. During most cases where a transpolar arc is observed to move across the polar region, and form a theta aurora, there are brief (minutes) southward excursions of IMF B-z, however northward IMF is required prior to theta aurora formation. Observations show that theta aurora can form during strictly northward IMF with its motion consistent with a change in sign of IMF B-y. It is important to note that since transpolar arcs can persist for 20-30 min after the IMF turns southward, errors will occur in assigning instantaneous IMF conditions to "snapshots'' of particular auroral patterns. We consider the entire evolution of the theta aurora and the changing IMF conditions. The influence of IMF B-y is best illustrated by examples which occur during steady northward IMF as compared to times when the IMF is northward on average. We show examples, provided by the Polar UV imager, when the IMF is steady northward. For one case, DMSP F13 and F14 provide in situ measurements of precipitating particles, ionospheric plasma flows and ion density. This unique data set enables us to analyze in detail the evolution of a theta aurora, in one case crossing the entire polar region. No sign change in B-z is needed for theta aurora formation. C1 Univ Texas, Ctr Space Sci, Richardson, TX 75083 USA. Royal Inst Technol, Alfven Lab, S-10044 Stockholm, Sweden. Univ Alabama, Ctr Space Plasma & Aeron Res, Huntsville, AL 35899 USA. NASA Headquarters, Geosp Sci OSS, Washington, DC 20546 USA. RP Univ Texas, Ctr Space Sci, Richardson, TX 75083 USA. EM cumnock@utdallas.edu OI Coley, William Robin/0000-0003-2047-0002 NR 22 TC 27 Z9 27 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 JUL PY 2002 VL 107 IS A7 AR 1108 DI 10.1029/2001JA009126 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 610VQ UT WOS:000178982500042 ER PT J AU Green, JL Sandel, BR Fung, SF Gallagher, DL Reinisch, BW AF Green, JL Sandel, BR Fung, SF Gallagher, DL Reinisch, BW TI On the origin of kilometric continuum SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE kilometric continuum; plasma waves; plasmasphere; radio sounding; remote sensing ID RADIO PLASMA IMAGER; NONTHERMAL CONTINUUM; RADIATION; TERRESTRIAL; LOCATION; EARTH AB [1] The Radio Plasma Imager (RPI) and the extreme ultraviolet (EUV) imager instruments on the polar orbiting IMAGE satellite are providing new observations of the source region of kilometric continuum. Observations by the IMAGE instruments are now able to clarify some aspects of the source of this emission and put some previous observations into a new perspective. The IMAGE observations show that kilometric continuum is generated at the plasmapause, from sources in or very near the magnetic equator, within a bite-out region of the plasmasphere. It is not known if the bite-out region is a necessary condition for the generation of kilometric continuum. From ray-tracing calculations in a model plasmasphere having a bite-out feature, it is found that a kilometric continuum source can produce a relatively narrow emission cone that is largely confined to the longitudinal extent of the bite-out structure. Since the bite-out structure is observed to corotate with the plasmasphere, so would the beamed kilometric continuum. In addition, the observed narrow latitudinal extent of the emission cone does not appear to be a propagation effect but is perhaps produced by the emission mechanism, such as the linear or nonlinear mode-conversion processes at the upper hybrid resonance proposed by a number of investigators. The processes by which bite-out structures are produced in the plasmasphere are not completely understood at this time. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Massachusetts, Ctr Atmospher Res, Lowell, MA 01854 USA. RP Green, JL (reprint author), NASA, Goddard Space Flight Ctr, Code 630, Greenbelt, MD 20771 USA. RI Fung, Shing/F-5647-2012 NR 24 TC 23 Z9 23 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JUL PY 2002 VL 107 IS A7 AR 1105 DI 10.1029/2001JA000193 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 610VQ UT WOS:000178982500045 ER PT J AU Keller, KA Hesse, M Kuznetsova, M Rastatter, L Moretto, T Gombosi, TI DeZeeuw, DL AF Keller, KA Hesse, M Kuznetsova, M Rastatter, L Moretto, T Gombosi, TI DeZeeuw, DL TI Global MHD modeling of the impact of a solar wind pressure change SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE solar wind pressure changes ID TRAVELING CONVECTION VORTICES; FIELD-ALIGNED CURRENTS; DYNAMIC PRESSURE; NORTHWARD IMF; MAGNETOSPHERE; GENERATION; SIMULATION; IONOSPHERE AB [1] A sudden increase in the solar wind dynamic pressure compresses the magnetosphere and launches compressional waves into the magnetosphere. The global response of the magnetosphere, including the ionosphere and the location of the field-aligned current (FAC) generation, to a step increase in the solar wind density has been studied using a global three-dimensional adaptive MHD model. As the density increase propagated along the flanks of the magnetopause, a two-phased response was seen in the ionosphere. The first response was an increase in FACs near the polar cap. For this response we found the location of FACs to lie just inside the magnetosphere. The second response was an increase in FACs at lower latitudes. The increase in FACs was in the same direction as region 1 currents. For the second response we found the location of FACs to fall well within the magnetosphere. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Michigan, Space Phys Res Lab, Ann Arbor, MI 48109 USA. RP Keller, KA (reprint author), NASA, Goddard Space Flight Ctr, Code 696, Greenbelt, MD 20771 USA. RI De Zeeuw, Darren/F-3667-2011; Hesse, Michael/D-2031-2012; Rastaetter, Lutz/D-4715-2012; Kuznetsova, Maria/F-6840-2012; Gombosi, Tamas/G-4238-2011; Moretto, Therese/B-6846-2013 OI Rastaetter, Lutz/0000-0002-7343-4147; Gombosi, Tamas/0000-0001-9360-4951; Moretto, Therese/0000-0002-2403-5561 NR 16 TC 26 Z9 27 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JUL PY 2002 VL 107 IS A7 AR 1126 DI 10.1029/2001JA000060 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 610VQ UT WOS:000178982500024 ER PT J AU Sigsbee, K Cattell, CA Fairfield, D Tsuruda, K Kokubun, S AF Sigsbee, K Cattell, CA Fairfield, D Tsuruda, K Kokubun, S TI Geotail observations of low-frequency waves and high-speed earthward flows during substorm onsets in the near magnetotail from 10 to 13 R-E SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE wavelet transform; Pi2 pulsations; lower hybrid waves; magnetotail; plasma sheet; substorms ID SPIKY ELECTRIC-FIELDS; PLASMA SHEET BOUNDARY; CURRENT DISRUPTION; INNER MAGNETOTAIL; PI2 PULSATIONS; CURRENT WEDGE; PARTICLE; EVENT; MAGNETOSPHERE; INSTABILITY AB [1] Geotail electric and magnetic field data from five substorms were used to examine the relationship between low-frequency waves and high-speed earthward flows at radial distances between 10 and 13 R-E. Strong compressional fluctuations of the magnetic field in the Pi2 frequency range (0.007-0.03 Hz) were observed during the 26 April 1995 substorm and the other four substorms studied, in association with high-speed earthward flows and magnetic field dipolarizations. However, the maximum earthward flow was generally observed 30 s to a few minutes after the start of the dipolarizations and magnetic field fluctuations in the Pi2 frequency range. Waves near the ion gyrofrequency (similar to0.1-1.0 Hz) and the lower hybrid frequency (similar to5-16 Hz) were also observed during all five substorms. The maximum amplitudes at these frequencies were not observed until after the start of the magnetic field dipolarization and earthward flow, which does not appear to be consistent with local substorm initiation by a cross-field current driven instability. Recent work has shown the importance of high-speed earthward flow bursts as drivers of substorm activity. However, we found that the earthward kinetic energy flux was much smaller than the Poynting flux or the thermal energy. This is consistent with the idea that currents driven by thermal pressure gradients and magnetic field changes are responsible for a major part of the substorm current wedge. C1 Univ Minnesota, Sch Phys & Astron, Minneapolis, MN 55455 USA. Inst Space & Astronaut Sci, Sagamihara, Kanagawa 229, Japan. Nagoya Univ, Solat Terr Environm Lab, Nagoya, Aichi, Japan. RP Sigsbee, K (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. RI Pfaff, Robert/F-5703-2012; OI Pfaff, Robert/0000-0002-4881-9715; Sigsbee, Kristine/0000-0001-8727-380X; Cattell, Cynthia/0000-0002-3805-320X NR 38 TC 45 Z9 45 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JUL PY 2002 VL 107 IS A7 AR 1141 DI 10.1029/2001JA000166 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 610VQ UT WOS:000178982500009 ER PT J AU Slavin, JA Fairfield, DH Lepping, RP Hesse, M Ieda, A Tanskanen, E Ostgaard, N Mukai, T Nagai, T Singer, HJ Sutcliffe, PR AF Slavin, JA Fairfield, DH Lepping, RP Hesse, M Ieda, A Tanskanen, E Ostgaard, N Mukai, T Nagai, T Singer, HJ Sutcliffe, PR TI Simultaneous observations of earthward flow bursts and plasmoid ejection during magnetospheric substorms SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID COLLISIONLESS MAGNETIC RECONNECTION; TRAVELING COMPRESSION REGIONS; GEOTAIL OBSERVATIONS; CURRENT DISRUPTION; INNER MAGNETOTAIL; PI2 PULSATIONS; CURRENT WEDGE; ION FLOW; SPACECRAFT OBSERVATIONS; IONOSPHERIC RESPONSE AB [1] Examination of observations taken by radially aligned International Solar Terrestrial Physics spacecraft in the nightside magnetosphere on 9 July 1997 has revealed close temporal correlations between earthward flow bursts in the plasma sheet and the ejection of plasmoids. A one-dimensional model of plasma sheet flow is applied to these observations to determine the time and location for the initiation of lobe flux tube reconnection. For the single clear flow burst-plasmoid pair observed during the first substorm and the three pairs produced by the second substorm, lobe flux reconnection was inferred to have started at X similar to -15 to -18 R-E, respectively, about 2-5 min prior to the observations of substorm expansion phase onset. These time delays and propagation speeds are shown to be consistent with the measured plasma sheet bulk flow speeds. Substorm expansion phase onset was essentially coincident with the arrival of the flow bursts at Geotail, which was located near the inner edge of the plasma sheet at X similar to -9 R-E. The dipolarization of the magnetic field at geosynchronous orbit, auroral kilometric radiation (AKR) emissions, Pi2 pulsations, high-latitude negative magnetic bays, and auroral breakup marking substorm expansion onset are all coincident within the +/-1 min resolution of the measurements. Accordingly, it appears that earthward of the inner edge of the plasma sheet, where Geotail was located, substorm effects propagated at speeds comparable to the Alfven speed characteristic of the high-latitude inner magnetosphere, similar to10(3) km s(-1). In summary, the results of our investigation strongly support the modern near-Earth neutral line (NENL) model of substorms in which the onset of lobe flux tube reconnection in the near tail is followed similar to2-5 min later by the braking of earthward flow bursts as they encounter the inner magnetosphere and within similar to1 min, by Pi2s generations, current wedge development, and AKR and auroral expansion, and finally, similar to10-20 min later, by the tailward retreat of the neutral line and either the development of a new NENL or the initiation of the recovery phase. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. Finnish Meteorol Inst, Div Geophys, FIN-00101 Helsinki, Finland. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Inst Space & Astronaut Sci, Sagamihara, Kanagawa 229, Japan. Tokyo Inst Technol, Dept Earth & Planetary Sci, Meguro Ku, Tokyo 1528551, Japan. NOAA, Space Environm Lab, Boulder, CO 80303 USA. Hermanus Magnet Observ, ZA-7200 Hermanus, South Africa. RP Slavin, JA (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. RI Hesse, Michael/D-2031-2012; Slavin, James/H-3170-2012; Sutcliffe, Peter/E-8124-2014 OI Slavin, James/0000-0002-9206-724X; NR 81 TC 51 Z9 52 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JUL PY 2002 VL 107 IS A7 AR 1106 DI 10.1029/2000JA003501 PG 33 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 610VQ UT WOS:000178982500044 ER PT J AU Soraas, F Aarsnes, K Oksavik, K Evans, DS AF Soraas, F Aarsnes, K Oksavik, K Evans, DS TI Ring current intensity estimated from low-altitude proton observations SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE ring current; Dst; proton precipitation ID PITCH-ANGLE SCATTERING; GEOMAGNETIC STORMS; PRECIPITATION; DST; LOSSES; SHEET; PHASE; IONS AB [1] Using data from the low-altitude polar orbiting satellite NOAA-15 the proton precipitation rate into the upper atmosphere can be monitored with a 100-min time resolution. From the total power of precipitating protons in the midnight/evening local time sector, a parameter Q(t) is used as a proxy for estimating the energy injection rate into the ring current (RC) due to energetic protons. The injection rate Q(t) is not based upon solar wind parameters but directly on the observed proton precipitation rate. This is done under the assumption that the loss cone acts as a "splash catcher'' for the protons injected into the RC. The protons in the loss cone thus do not represent a loss from the RC but are, in fact, a measure of the proton injection rate into the RC. Using the Burton equation and Q(t) as a measure for the true energy injection rate, a value proportional to the energy content in the RC due to energetic protons can be calculated. Assuming a decay constant for the ions in the RC and that the magnetic field depression is proportional to the RC energy content, a RC index can be determined. When Dst is corrected for magnetopause and tail currents, the linear correlation coefficient between the corrected Dst* and the RC index is between 0.8 and 0.9; thus similar to70-80% of the variance in this corrected Dst* can be accounted for. The high correlation strongly indicates that Q(t) is a measure of the true energy injection rate and that Dst* is a measure of the energy content in the RC. Observations of proton precipitation measured by low-altitude polar-orbiting satellites thus have the potential for deriving a space-based Dst index in near real time that is not influenced by magnetic fields generated by magnetopause, field-aligned, and tail currents. C1 Univ Bergen, Dept Phys, N-5007 Bergen, Norway. NASA, Space Environm Ctr, Boulder, CO 80305 USA. RP Soraas, F (reprint author), Univ Bergen, Dept Phys, Allegaten 55, N-5007 Bergen, Norway. NR 32 TC 26 Z9 26 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JUL PY 2002 VL 107 IS A7 AR 1149 DI 10.1029/2001JA000123 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 610VQ UT WOS:000178982500001 ER PT J AU Atkins, SC AF Atkins, SC TI Estimating departure queues to study runway efficiency SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article AB The ability to analyze the current efficiency of surface operations is limited by the lack of availability of surface surveillance data. To study surface and departure issues and identify opportunities for automation to improve traffic management, a method is presented for reconstructing the departure queues that existed at each runway from available information. Observations of the departure queues are of particular interest because they provide insight into the management of departures before takeoff. The method correlates pushback data and radar data to estimate the departure runway, the takeoff time, and the time at which the aircraft joins the departure queue, for every departure. By the calculation of the interval of time for which each aircraft is waiting at the runway, the departure queue at each runway can be reconstructed at every point in time. This method is used to study five days of data from Dallas/Fort Worth airport. Substantial departure queues and delays are observed, consistent with expectations for a hub airport. Moreover, knowledge of the departure queues provides insight into the efficiency with which the departure runways were used. The departure queues on the primary departure runways are shown to be well balanced at most times. However, during periods of time when departure demand was present at the runway, the interdeparture gaps exhibit significant variability. These delays between consecutive departures may indicate an opportunity for automation to increase throughput. C1 NASA, Ames Res Ctr, Terminal Area Air Traff Management Res Branch, Moffett Field, CA 94035 USA. RP Atkins, SC (reprint author), NASA, Ames Res Ctr, Terminal Area Air Traff Management Res Branch, Mail Stop 210-6, Moffett Field, CA 94035 USA. NR 11 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 USA SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD JUL-AUG PY 2002 VL 25 IS 4 BP 651 EP 657 DI 10.2514/2.4959 PG 7 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 571WP UT WOS:000176742400006 ER PT J AU Lind, R AF Lind, R TI Linear parameter-varying modeling and control of structural dynamics with aerothermoelastic effects SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article ID HYPERSONIC VEHICLE MODEL; AIRCRAFT; DESIGN; SYSTEMS AB Structural dynamics can introduce low-frequency modes that must be considered for modeling and control of flexible aircraft. Furthermore, the modal dynamics can be affected by operating conditions such as temperature. A linear parameter-varying (LPV) Framework is used to represent structural dynamics. The framework represents the dynamics with dependency on operating parameters as a set of state-space matrices that are affine functions of those parameters. Controllers can then be formulated as state-space matrices that are also affine functions of the parameters. The controller, thus, changes with the operating parameters so that it is inherently gain scheduled. Such a controller is beneficial compared to traditional controllers because of the guaranteed closed-loop properties over time-varying trajectories of the operating conditions. The LPV framework is used to account for the aerothermoelastic effects on the structural dynamics of a generic hypersonic vehicle. A controller that is gain scheduled over temperature is synthesized to damp actively the modal dynamics that vary across a flight profile. C1 NASA, Dryden Flight Res Ctr, Aerostruct Branch, Edwards AFB, CA 93523 USA. RP Lind, R (reprint author), Univ Florida, Dept Aerosp Engn Mech & Engn Sci, 231 Aerosp Bldg, Gainesville, FL 32611 USA. NR 26 TC 63 Z9 71 U1 3 U2 22 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 JUL-AUG PY 2002 VL 25 IS 4 BP 733 EP 739 DI 10.2514/2.4940 PG 7 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 571WP UT WOS:000176742400015 ER PT J AU Brenner, MJ AF Brenner, MJ TI Aeroservoelastic model uncertainty bound estimation from flight data SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article ID FREQUENCY-RESPONSE DATA; PARAMETER-ESTIMATION; IDENTIFICATION; DOMAIN; DESIGN AB Uncertainty modeling is a critical element in the estimation of robust stability margins for stability, boundary prediction and robust flight control system development. There has been a serious deficiency to date in aeroservoelastic data analysis with attention to uncertainty modeling. Uncertainty can be estimated from flight data using both parametric and nonparametric identification techniques. The model validation problem addressed here is to identify aeroservoelastic models with associated uncertainty structures from a limited amount of controlled excitation inputs over an extensive flight envelope. The challenge is to update analytical models from flight data estimates while also deriving nonconservative uncertainty descriptions consistent with the flight data. Transfer function estimates are incorporated in a robust minimax estimation scheme to update models and get error bounds consistent with the data and model structure. Uncertainty estimates derived from the data in this manner provide an appropriate and relevant representation for model development and robust stability analysis. The method incorporates parametric and nonparamteric uncertainty into various uncertainty structures for quantitative measures of robust stability relating to parameter variations and unmodeled dynamics. This model-plus-uncertainty identification procedure is applied to aeroservoelastic flight data from the NASA Dryden Flight Research Center F-18 Systems Research Aircraft. C1 NASA, Dryden Flight Res Ctr, Aerostruct Branch, Edwards AFB, CA 93523 USA. RP Brenner, MJ (reprint author), NASA, Dryden Flight Res Ctr, Aerostruct Branch, MS 4840D-RS, Edwards AFB, CA 93523 USA. NR 32 TC 10 Z9 10 U1 1 U2 1 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 JUL-AUG PY 2002 VL 25 IS 4 BP 748 EP 754 DI 10.2514/2.4942 PG 7 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 571WP UT WOS:000176742400017 ER PT J AU Cerf, NJ Durt, T Gisin, N AF Cerf, NJ Durt, T Gisin, N TI Cloning a qutrit SO JOURNAL OF MODERN OPTICS LA English DT Article; Proceedings Paper CT Conference on Quantum Information Theory and Quantum Computing CY JUL 10-18, 2001 CL GDANSK, POLAND ID ASYMMETRIC QUANTUM CLONING; STATES AB Several classes of state-dependent quantum cloners for three-level systems are investigated. These cloners optimally duplicate some of the four maximally-conjugate bases with an equal fidelity, thereby extending the phase-covariant qubit cloner to qutrits. Three distinct classes of qutrit cloners can be distinguished, depending on whether two, three, or four maximally-conjugate bases are cloned as well (the latter case simply corresponds to the universal qutrit cloner). These results apply to symmetric as well as asymmetric cloners, so that the balance between the fidelity of the two clones can also be analysed. C1 Free Univ Brussels, TENA, B-1050 Brussels, Belgium. Univ Geneva, Grp Appl Phys Opt, Geneva 4, Switzerland. Free Univ Brussels, Ecole Polytech, B-1050 Brussels, Belgium. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Durt, T (reprint author), Free Univ Brussels, TENA, Pleinlaan 2, B-1050 Brussels, Belgium. EM thomdurt@vub.ac.be NR 16 TC 36 Z9 39 U1 0 U2 2 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0950-0340 EI 1362-3044 J9 J MOD OPTIC JI J. Mod. Opt. PD JUL PY 2002 VL 49 IS 8 BP 1355 EP 1373 DI 10.1080/09500340110109043 PG 19 WC Optics SC Optics GA 564LT UT WOS:000176316400014 ER PT J AU Nadeau, H Lester, HA AF Nadeau, H Lester, HA TI NRSF causes cAMP-sensitive suppression of sodium current in cultured hippocampal neurons SO JOURNAL OF NEUROPHYSIOLOGY LA English DT Article ID RESTRICTIVE SILENCER FACTOR; CHANNEL ALPHA-SUBUNIT; ACTIVITY-DEPENDENT REGULATION; GENE-EXPRESSION; NERVOUS-SYSTEM; TRANSCRIPTION FACTOR; ELECTRICAL-ACTIVITY; LENTIVIRAL VECTORS; PYRAMIDAL NEURONS; POTASSIUM CHANNEL AB The neuron restrictive silencer factor (NRSF/REST) has been shown to bind to the promoters of many neuron-specific genes and is able to suppress transcription of Na+ channels in PC12 cells, although its functional effect in terminally differentiated neurons is unknown. We constructed lentiviral vectors to express NRSF as a bicistronic message with green fluorescent protein (GFP) and followed infected hippocampal neurons in culture over a period of 1-2 wk. NRSF-expressing neurons showed a time-dependent suppression of Na+ channel function as measured by whole cell electrophysiology. Suppression was reversed or prevented by the addition of membrane-permeable cAMP analogues and enhanced by cAMP antagonists but not affected by increasing protein expression with a viral enhancer. Secondary effects, including altered sensitivity to glutamate and GABA and reduced outward K+ currents, were duplicated by culturing GFP-infected control neurons in TTX. The striking similarity of the phenotypes makes NRSF potentially useful as a genetic "silencer" and also suggests avenues of further exploration that may elucidate the transcription factor's in vivo role in neuronal plasticity. C1 CALTECH, Div Biol, Pasadena, CA 91125 USA. RP Nadeau, H (reprint author), CALTECH, Jet Prop Lab, M-S 183-301,4800 Oak Grove Dr, Pasadena, CA 91109 USA. FU NIMH NIH HHS [MH-490176] NR 56 TC 10 Z9 10 U1 1 U2 6 PU AMER PHYSIOLOGICAL SOC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 0022-3077 J9 J NEUROPHYSIOL JI J. Neurophysiol. PD JUL PY 2002 VL 88 IS 1 BP 409 EP 421 DI 10.1152/jn.01038.2001 PG 13 WC Neurosciences; Physiology SC Neurosciences & Neurology; Physiology GA 567PT UT WOS:000176493800038 PM 12091564 ER PT J AU Johnson, LK Spanjers, GG Bromaghim, DR Dulligan, MW Hoskins, WA AF Johnson, LK Spanjers, GG Bromaghim, DR Dulligan, MW Hoskins, WA TI On-orbit optical observations of Electric Propulsion Space Experiment 26-kilowatt arcjet SO JOURNAL OF PROPULSION AND POWER LA English DT Article AB During the course of eight flight firings of the ESEX 26-kW arcjet in March and April 1999, optical observations from onboard and ground-based sensors were obtained. Images of the thruster plume at 656 nm confirm expectations that the plume luminescence in,the space environment is more compact than that from a thruster operated in the laboratory at higher background pressure. Observations using a ground-based telescope reveal blackbody and line emission spectrum over the range 325-675 nm. The spectral features are consistent with ground tests. Line ratios observed in flight show a moderately higher degree of excitation than ground tests, which is consistent both with the higher specific power and the less collisional plume expansion of the flight test compared to ground tests. C1 Aerosp Corp, Elect Prop Space Expt, El Segundo, CA 90245 USA. USAF, Res Lab, Prop Directorate, Elect Prop Space Expt Program, Edwards AFB, CA 93524 USA. ERC Inc, Edwards AFB, CA 93524 USA. Gen Dynam Corp, Ordnance & Tact Syst, Redmond, WA 98073 USA. RP Johnson, LK (reprint author), CALTECH, Jet Prop Lab, Thermal & Prop Engn Dept, Mail Stop 125-109,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 16 TC 1 Z9 2 U1 0 U2 1 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 JUL-AUG PY 2002 VL 18 IS 4 BP 763 EP 767 DI 10.2514/2.6030 PG 5 WC Engineering, Aerospace SC Engineering GA 575EQ UT WOS:000176934100007 ER PT J AU Adams, RB Landrum, DB AF Adams, RB Landrum, DB TI Analysis of a fusion-electric airbreathing earth to orbit launch vehicle SO JOURNAL OF PROPULSION AND POWER LA English DT Article AB A novel, advanced airbreathing propulsion system, the simultaneous heating and expansion (SHX) engine, is proposed. The SHX uses coherent beam emitters to couple energy generated by a fusion reactor to the engine flowpath. A quasi-one-dimensional model was developed to calculate axial flow properties in the inlet, combustor, and expansion sections. Models were developed for three different beam emitters: an HF laser, CO(2) laser, and electron beam. Mass relations for the engine components were derived from the literature. SHX simulations produced similar performance to an idealized scramjet, but superior performance in comparison to a baseline fusion rocket. These results indicate the SHX concept could potentially provide the significant performance increase required to meet launch cost goals set by NASA and is worthy of further study. C1 Int Space Syst Inc, Huntsville, AL 35816 USA. Univ Alabama, Propuls Res Ctr, Dept Mech & Aerosp Engn, Huntsville, AL 35899 USA. RP Adams, RB (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 19 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD JUL-AUG PY 2002 VL 18 IS 4 BP 933 EP 942 DI 10.2514/2.6019 PG 10 WC Engineering, Aerospace SC Engineering GA 575EQ UT WOS:000176934100029 ER PT J AU Adams, RB Landrum, DB AF Adams, RB Landrum, DB TI Laser-air interactions in an internal supersonic flowpath SO JOURNAL OF PROPULSION AND POWER LA English DT Article C1 Int Space Syst Inc, Huntsville, AL 35816 USA. Univ Alabama, Dept Mech & Aerosp Engn, Propuls Res Ctr, Huntsville, AL 35899 USA. RP Adams, RB (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 7 TC 1 Z9 1 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD JUL-AUG PY 2002 VL 18 IS 4 BP 961 EP 963 DI 10.2514/2.6023 PG 3 WC Engineering, Aerospace SC Engineering GA 575EQ UT WOS:000176934100032 ER PT J AU Devi, VM Benner, DC Smith, MAH Rinsland, CP Brown, LR AF Devi, VM Benner, DC Smith, MAH Rinsland, CP Brown, LR TI Self- and N-2-broadening, pressure induced shift and line mixing in the v(5) band of (12) CH3D using a multispectrum fitting technique SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article DE monodeuterated methane; infrared spectra; self-broadening; nitrogen-broadening; line mixing; Fourier transform infrared (FTIR) spectroscopy; spectral lineshape ID DIODE-LASER MEASUREMENTS; AIR-BROADENED WIDTH; 6-10 MU-M; NU(3) BAND; INFRARED BANDS; (CH3D)-C-12; COEFFICIENTS; INTENSITIES; TEMPERATURES; (H2O)-O-16 AB We report the first measured Lorentz self- and nitrogen-broadening and the corresponding pressure-shift coefficients in the v(5)(E) perpendicular band of (CH3D)-C-12 between 1275 and 1600 cm(-1). The multispectrum fitting technique allowed us to analyze simultaneously both self-broadened and N-2-broadened spectra recorded at 0.005 to 0.006-cm(-1) resolution with a Fourier transform spectrometer located at Kitt Peak. Self-broadening coefficients for over 550 transitions and self-shift coefficients for more than 480 transitions with rotational quantum numbers up to J" = 17 and K" = 14 were determined. Nitrogen-broadening and nitrogen pressure-induced shift coefficients were determined for more than 300 of those transitions. The measured broadening coefficients vary from 0.020 to about 0.091 cm-(1) atm(-1) at 296 K. The measured pressure-shift coefficients had values extending from about -0.014 to +0.005 cm(-1) atm(-1). Very few of the pressure-shift coefficients were positive, and the positive pressure-shift coefficients were mostly associated with the J" = K" transitions in the (P)Q sub-bands. The J" = K" transitions in the PP and R R sub-bands were associated with the smallest broadening coefficients. Our measurements also included 46 forbidden lines with DeltaK = +/-2 (10 P-O, 9 (O)Q, 3 P-Q, 7 (Q)Q, 1 R-Q, 13 (S)Q and 3 R-S). The off-diagonal relaxation matrix element coefficients, W-lj, in cm(-1) atm(-1) at 296 K which are associated with line mixing were determined for a few transitions with K" = 3 (A(+)A(-)splitting) in the P-P, (P)Q and P-R sub-bands. We have examined the dependence of the measured parameters on J.K quantum numbers and also developed empirical expressions to describe the broadening coefficients in terms of J and K. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 Coll William & Mary, Dept Phys, Williamsburg, VA 23187 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Devi, VM (reprint author), Coll William & Mary, Dept Phys, Box 8795, Williamsburg, VA 23187 USA. NR 24 TC 21 Z9 21 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD JUL 1 PY 2002 VL 74 IS 1 BP 1 EP 41 AR PII S0022-4073(01)00190-X PG 41 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 549VB UT WOS:000175466500001 ER PT J AU Goldman, A Rinsland, CP Perrin, A Flaud, JM Barbe, A Camy-Peyret, C Coffey, MT Mankin, WG Hannigan, JW Stephen, TM Devi, VM Smith, MAH AF Goldman, A Rinsland, CP Perrin, A Flaud, JM Barbe, A Camy-Peyret, C Coffey, MT Mankin, WG Hannigan, JW Stephen, TM Devi, VM Smith, MAH TI Weak ozone isotopic absorption in the 5 mu m region from high resolution FTIR solar spectra SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article DE atmospheric ozone isotopomers; infrared Fourier transform atmospheric spectroscopy; solar spectra ID BALLOON-BORNE; IDENTIFICATION AB Isotopic ozone lines of (OOO)-O-16-O-16-O-17 and (OOO)-O-16-O-17-O-16 in the 5 mum region are identified for the first time in balloon-borne high-resolution (0.003 cm(-1)) solar absorption spectra. A few of these lines also are observed in ground-based spectra. These lines need to be included in analysis of atmospheric absorption spectra, in addition to the recently identified (OOO)-O-16-O-16-O-18, (OOO)-O-16-O-18-O-16 and (OCS)-O-16-C-12-S-34 lines in this region. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 Univ Denver, Dept Phys, Denver, CO 80208 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Univ Paris 11, CNRS, Photophys Mol Lab, F-91405 Orsay, France. Fac Sci, GSMA, F-51062 Reims, France. Univ Paris 06, LPMA, F-75252 Paris 05, France. Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80303 USA. Coll William & Mary, Dept Phys, Williamsburg, VA 23187 USA. RP Goldman, A (reprint author), Univ Denver, Dept Phys, Denver, CO 80208 USA. NR 7 TC 8 Z9 9 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD JUL 1 PY 2002 VL 74 IS 1 BP 133 EP 138 AR PII S0022-4073(01)00185-6 DI 10.1016/S0022-4073(01)00185-6 PG 6 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 549VB UT WOS:000175466500009 ER PT J AU Lambert, JL Morookian, JM Sirk, SJ Borchert, MS AF Lambert, JL Morookian, JM Sirk, SJ Borchert, MS TI Measurement of aqueous glucose in a model anterior chamber using Raman spectroscopy SO JOURNAL OF RAMAN SPECTROSCOPY LA English DT Article ID CALIBRATION; ANALYTES AB Many laboratories have been developing techniques that might be applied toward a non-invasive device that could optically measure aqueous humor glucose in the eye as a surrogate for blood glucose. We have configured a confocal Raman microscope that is capable of acquiring the Raman spectra of the aqueous humor in vivo. However, because of the potential for optical toxicity, a major design consideration is evaluating the tradeoff between the energy of exposure and measurement accuracy. Toward this end, we have developed a physical model of the anterior chamber in the eye for studying the feasibility of using a confocal Raman microscope for determining the concentration of glucose and other metabolites. The Raman spectrum of aqueous humor closely resembles the spectrum of its four primary Raman scatterers, (glucose, urea, lactate and ascorbate) mixed in normal saline. Aqueous mixtures of these analytes were placed under a contact lens resting on a quartz plate to form a physical model of the anterior chamber filled with aqueous humor. Calibration standards were prepared by non-collinearly varying the measured concentrations of the analytes over a range of 0-13 times the mean physiological levels found in aqueous humor. A confocal microscope was used to acquire spectra using an excitation wavelength of 785 nm. The accuracy to which the concentration with analytes could be optically measured was evaluated using the partial least-squares (PLS) algorithm and spectral datasets collected using exposure energies of 75, 150, 300, 900, and 1800 mJ. The optimum standard error of prediction (SEP) obtained for glucose was 34.3 mg dl(-1) (2.72% of full range) using a 12-factor PLS model calculated using intensity-normalized spectra acquired over a free spectral range of 400-1800 cm(-1) with 900 mJ excitation energy. Clinically acceptable predictability (4.6%) was obtained with 300 mJ total excitation energy. Similar results were obtained for urea (SEP = 8.84 mg dl(-1), 1.88%), ascorbate (SEP = 17.1 mg dl(-1), 8.22%) and lactate (SEP = 82.9 mg dl(-1), 7.59%) using 900 mJ exposure. Our results suggest that Raman spectroscopy may provide a feasible method of non-invasive glucose measurement if ocular toxicity can be avoided. Copyright (C) 2002 John Wiley Sons, Ltd. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Childrens Hosp Los Angeles, Div Ophthalmol, Los Angeles, CA 90027 USA. RP Lambert, JL (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 23 TC 28 Z9 28 U1 0 U2 12 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0377-0486 J9 J RAMAN SPECTROSC JI J. Raman Spectrosc. PD JUL PY 2002 VL 33 IS 7 BP 524 EP 529 DI 10.1002/jrs.871 PG 6 WC Spectroscopy SC Spectroscopy GA 580KB UT WOS:000177232800006 ER PT J AU Vladimirova, T Katz, R AF Vladimirova, T Katz, R TI Third Military and Aerospace Programmable-Logic Devices International Conference (MAPLD'2000) SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Editorial Material C1 Univ Surrey, Surrey Space Ctr, Guildford GU2 5XH, Surrey, England. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Vladimirova, T (reprint author), Univ Surrey, Surrey Space Ctr, Guildford GU2 5XH, Surrey, England. NR 0 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 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD JUL-AUG PY 2002 VL 39 IS 4 BP 473 EP 473 DI 10.2514/2.3841 PG 1 WC Engineering, Aerospace SC Engineering GA 584RA UT WOS:000177480800001 ER PT J AU Daryabeigi, K AF Daryabeigi, K TI Thermal analysis and design optimization of multilayer insulation for reentry aerodynamic heating SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB A design-of-experiment technique was used to investigate optimum design of multilayer insulations for reentry aerodynamic heating. Combined radiation/conduction heat transfer in high-temperature multilayer insulations was modeled using a finite volume numerical model, which was validated by comparison with steady-state effective thermal conductivity measurements, and transient thermal tests simulating reentry aerodynamic heating conditions. It was found that use of 2-mm foil spacing and locating the foils near the hot boundary, with the top foil 2 mm away from the hot boundary, resulted in the most effective insulation design. A 76.2-mm-thick multilayer insulation using 1, 4, or 16 foils resulted in 2.9, 7.2, or 22.2% mass per unit area savings, respectively, compared to a fibrous insulation sample at the same thickness. C1 NASA, Langley Res Ctr, Met & Thermal Struct Branch, Hampton, VA 23681 USA. RP Daryabeigi, K (reprint author), NASA, Langley Res Ctr, Met & Thermal Struct Branch, Mail Stop 396, Hampton, VA 23681 USA. NR 23 TC 26 Z9 28 U1 0 U2 9 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD JUL-AUG PY 2002 VL 39 IS 4 BP 509 EP 514 DI 10.2514/2.3863 PG 6 WC Engineering, Aerospace SC Engineering GA 584RA UT WOS:000177480800007 ER PT J AU Lamassoure, E Saleh, JH Hastings, DE AF Lamassoure, E Saleh, JH Hastings, DE TI Space systems flexibility provided by on-orbit servicing: Part 2 SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB Spacecraft are still the only complex engineering systems without routine maintenance infrastructure. Whereas the technologies for autonomous on-orbit servicing of satellites are emerging, no general conclusions have yet been drawn regarding the cost effectiveness of on-orbit servicing. In a companion paper (Saleh, J. H., Lamassoure, E., and Hastings, D. E., "Space Systems Flexibility Provided by On-Orbit Servicing: Part 1," Journal of Spacecraft and Rockets, Vol. 39, No. 4, 2002, pp. 551-560), a new perspective on the problem was proposed, in which the value of servicing is studied independently from its cost. A framework to account for the value of the flexibility provided by on-orbit servicing to space systems was developed. Here, the usefulness of this framework is demonstrated by studying the value of servicing for two types of space missions. First commercial missions with uncertain revenues are considered. It is shown that traditional valuation has been underestimating mission value by not taking into account the option to abandon. Then servicing is considered as an option on life extension, showing how the optimal design life decreases with increasing uncertainty. A map of the maximum servicing price in a market level/market volatility space is proposed as a new tool for decision making. Then military missions faced with uncertainty in the location of contingencies are considered. The value of refueling for making spacecraft maneuverable is studied for two cases. For a radar constellation in low Earth orbit, servicing is shown to have little value due to a conflict between propulsion mass and maneuver time. For a geostationary fleet of communication satellites, servicing is' shown to have value based on the potential improvements in capacity usage. C1 MIT, Dept Aeronaut & Astronaut, Cambridge, MA 02139 USA. RP Lamassoure, E (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. RI Hastings, Daniel/J-3774-2015 OI Hastings, Daniel/0000-0003-4421-5110 NR 17 TC 13 Z9 13 U1 2 U2 4 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD JUL-AUG PY 2002 VL 39 IS 4 BP 561 EP 570 DI 10.2514/2.3845 PG 10 WC Engineering, Aerospace SC Engineering GA 584RA UT WOS:000177480800013 ER PT J AU Rayman, MD Williams, SN AF Rayman, MD Williams, SN TI Design of the first interplanetary solar electric propulsion mission SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article ID TECHNOLOGY VALIDATION MISSION; DEEP-SPACE-1 AB Deep Space 1 was the first interplanetary mission to be propelled by solar electric propulsion. The detailed design, development, and analysis of its trajectory have led to important new insights into the design of low-thrust trajectories. Tying the testing of solar electric propulsion technology to an operational mission has allowed the identification of trajectory design issues that were not considered in concept studies, such as constraints on the spacecraft attitude and periods of thrusting or coasting that are dictated by reasons other than trajectory considerations. Models of the spacecraft performance unimportant for trajectory analysis in missions using conventional chemical propulsion are intimately connected with the design of the trajectory when solar electric propulsion is employed. In addition, mass margin is not sufficient to assess a low-thrust mission. Unplanned thrust interruptions may result in a situation in which the propulsion system cannot provide sufficient impulse to compensate for the lost thrust in time to reach encounter targets. Mission margin (as distinct from mass margin) is a quantification of the mission's susceptibility to loss of thrust and is an important indicator of mission robustness for low-thrust trajectories. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Jet Prop Lab, Navigat & Mission Design Sect, Pasadena, CA 91109 USA. RP Rayman, MD (reprint author), CALTECH, Jet Prop Lab, Deep Space 1,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 TC 44 Z9 49 U1 1 U2 8 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD JUL-AUG PY 2002 VL 39 IS 4 BP 589 EP 595 DI 10.2514/2.3848 PG 7 WC Engineering, Aerospace SC Engineering GA 584RA UT WOS:000177480800016 ER PT J AU Thode, A Mellinger, DK Stienessen, S Martinez, A Mullin, K AF Thode, A Mellinger, DK Stienessen, S Martinez, A Mullin, K TI Depth-dependent acoustic features of diving sperm whales (Physeter macrocephalus) in the Gulf of Mexico SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Article; Proceedings Paper CT 141st Meeting of the Acoustical-Society-of-America CY JUN 04-08, 2001 CL CHICAGO, ILLINOIS SP Acoust Soc Amer ID GALAPAGOS-ISLANDS; HYDROPHONE ARRAY; SOUND; ENVIRONMENT; SCATTERING; BEHAVIOR; CLICKS; FISH AB Three-dimensional dive trajectories of three sperm whales in the Gulf of Mexico have been obtained by measuring the relative arrival times and bearings of the animals' acoustic multipath reflections, using two elements of a towed hydrophone array deployed at an unknown depth and orientation, Within the first 6-12 min of the start of a dive, the intervals between successive "clicks" of all three whales corresponded closely with the two-way travel time of an acoustic pulse traveling vertically between the animals' position and the ocean bottom. The click spectra contained multiple peaks, including a faint band of energy originally centered near 10 kHz. As the animals descended over 500 in in depth, the center frequency of this band shifted to nearly 15 kHz, hilt subsequently remained clear this value during the rest of the dive. This frequency shift is consistent with that expected from energy scattering from an ensemble of incompressible small-scale air-filled resonators, with diameters on the order of 4 mm. One possible candidate for such all ensemble is proposed to reside in the collapsed frontal sac of the animal. A comparison of the received levels for the bottom and direct multipath arrivals indicates that the whales' acoustic directivity must range between 10-30 dB in the 5-20-kHz region. (C) 2002 Acoustical Society of America. C1 MIT, Dept Ocean Engn, Cambridge, MA 02139 USA. Oregon State Univ, Cooperat Inst Marine Resources Studies, Newport, OR 97365 USA. Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Seattle, WA 98115 USA. Natl Marine Fisheries Serv, SE Fisheries Sci Ctr, Miami, FL 33149 USA. Natl Marine Fisheries Serv, SE Fisheries Sci Ctr, Pascagoula, MS 39568 USA. RP Thode, A (reprint author), Univ Calif San Diego, Scripps Inst Oceanog, Marine Phys Lab, La Jolla, CA 92093 USA. NR 60 TC 49 Z9 52 U1 3 U2 12 PU ACOUSTICAL SOC AMER AMER INST PHYSICS PI MELVILLE PA STE 1 NO 1, 2 HUNTINGTON QUADRANGLE, MELVILLE, NY 11747-4502 USA SN 0001-4966 J9 J ACOUST SOC AM JI J. Acoust. Soc. Am. PD JUL PY 2002 VL 112 IS 1 BP 308 EP 321 DI 10.1121/1.1482077 PG 14 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA 573FR UT WOS:000176819100033 PM 12141357 ER PT J AU Everett, RA Newman, JC Phillips, EP AF Everett, RA Newman, JC Phillips, EP TI The effects of a machining-like scratch on the fatigue life of 4340 steel SO JOURNAL OF THE AMERICAN HELICOPTER SOCIETY LA English DT Article AB The main objective of this study was to assess the effects of a machine-like scratch on the fatigue life of 4340 steel, heat treated to an ultimate strength of 210 ksi. To accomplish this, constant amplitude fatigue tests were conducted on unnotched specimens with and without a 0.002 inch deep machining scratch on the specimen surfaces. Specimens were also tested that had been shot peened after the scratch was put on the specimen surfaces to determine if the compressive residual stresses from the shot peening would negate any possible effect the scratch might have on fatigue life. An analysis based on small-crack fracture mechanics was evaluated in its ability to predict the total fatigue life of the tests with and without the machine-like scratch. C1 USA, NASA, Langley Res Ctr, Res Lab,Vehicle technol Directorate, Hampton, VA 23684 USA. RP Everett, RA (reprint author), USA, NASA, Langley Res Ctr, Res Lab,Vehicle technol Directorate, Hampton, VA 23684 USA. NR 17 TC 1 Z9 1 U1 0 U2 1 PU AMER HELICOPTER SOC INC PI ALEXANDRIA PA 217 N WASHINGTON ST, ALEXANDRIA, VA 22314 USA SN 0002-8711 J9 J AM HELICOPTER SOC JI J. Am. Helicopter Soc. PD JUL PY 2002 VL 47 IS 3 BP 151 EP 155 PG 5 WC Engineering, Aerospace SC Engineering GA 576GP UT WOS:000176995400001 ER PT J AU Fasanella, EL Jackson, KE Lyle, KH AF Fasanella, EL Jackson, KE Lyle, KH TI Finite element simulation of a full-scale crash test of a composite helicopter SO JOURNAL OF THE AMERICAN HELICOPTER SOCIETY LA English DT Article AB A finite element model of the Sikorsky Advanced Composite Airframe Program (ACAP) helicopter was developed using the nonlinear, explicit transient dynamic code, MSC.Dytran. Analytical predictions were correlated with experimental data obtained from a full-scale crash test of the Sikorsky ACAP helicopter flight test article that was conducted at the Impact Dynamics Research Facility of NASA Langley Research Center. The helicopter was impacted at 38 ft/s vertical and 32.5 ft/s forward velocity with an attitude of 6.25 nose-up pitch and 3.5 left-down roll. The objective of the crash simulation was to evaluate the capabilities of a commercially available transient dynamic analysis code in predicting the response of a composite airframe subjected to impact loading. The model was developed from an existing MSC.Nastran modal-vibration model of the helicopter. Considerable modifications were made in converting the original modal-vibration model to a model for crash simulation. Following conversion of the model, a two-stage modeling approach was used to generate analytical predictions. Because of the relatively long pulse duration, a rigid structural model containing a fairly complex landing gear model was executed from initial contact through landing gear stroke. Prior to fuselage contact, the nodal displacements and velocities were output to a file. Then, a flexible structural model was executed with the nodal displacements and velocities used as initial conditions. This paper describes the development of the finite element crash model, the two-stage modeling approach, and the correlation of the analytical predictions with the experimental data from the full-scale crash test of the ACAP helicopter. C1 USA, NASA, Langley Res Ctr, Res Lab,Vehicle Technol Directorate, Hampton, VA 23681 USA. RP Fasanella, EL (reprint author), USA, NASA, Langley Res Ctr, Res Lab,Vehicle Technol Directorate, Hampton, VA 23681 USA. NR 13 TC 8 Z9 8 U1 0 U2 6 PU AMER HELICOPTER SOC INC PI ALEXANDRIA PA 217 N WASHINGTON ST, ALEXANDRIA, VA 22314 USA SN 0002-8711 J9 J AM HELICOPTER SOC JI J. Am. Helicopter Soc. PD JUL PY 2002 VL 47 IS 3 BP 156 EP 168 PG 13 WC Engineering, Aerospace SC Engineering GA 576GP UT WOS:000176995400002 ER PT J AU Kvaternik, RG Piatak, DJ Nixon, MW Langston, CW Singleton, JD Bennett, RL Brown, RK AF Kvaternik, RG Piatak, DJ Nixon, MW Langston, CW Singleton, JD Bennett, RL Brown, RK TI An experimental evaluation of Generalized Predictive Control for Tiltrotor aeroelastic stability augmentation in airplane mode of flight SO JOURNAL OF THE AMERICAN HELICOPTER SOCIETY LA English DT Article AB The results of a joint NASA/Army/Bell Helicopter Textron wind-tunnel test to assess the potential of Generalized Predictive Control (GPC) for actively controlling the swashplate of tiltrotor aircraft to enhance aeroelastic stability in the airplane mode of flight are presented. GPC is an adaptive time-domain predictive control method that uses a linear difference equation to describe the input-output relationship of the system and to design the controller. The test was conducted in the Langley Transonic Dynamics Tunnel using an unpowered 1/5-scale semispan aeroelastic model of the V-22 that was modified to incorporate a GPC-based multi-input multi-output control algorithm to individually control each of the three swashplate actuators. Wing responses were used for feedback. The GPC-based control system was highly effective in increasing the stability of the critical wing mode for all of the conditions tested, without measurable degradation of the damping in the other modes. The algorithm was also robust with respect to its performance in adjusting to rapid changes in both the rotor speed and the tunnel airspeed. C1 USA, NASA, Langley Res Ctr, Res Lab,Vehicle Technol Directorate, Hampton, VA 23665 USA. Bell Helicopter Textron, Ft Worth, TX USA. RP Kvaternik, RG (reprint author), USA, NASA, Langley Res Ctr, Res Lab,Vehicle Technol Directorate, Hampton, VA 23665 USA. NR 33 TC 7 Z9 7 U1 1 U2 2 PU AMER HELICOPTER SOC INC PI ALEXANDRIA PA 217 N WASHINGTON ST, ALEXANDRIA, VA 22314 USA SN 0002-8711 J9 J AM HELICOPTER SOC JI J. Am. Helicopter Soc. PD JUL PY 2002 VL 47 IS 3 BP 198 EP 208 PG 11 WC Engineering, Aerospace SC Engineering GA 576GP UT WOS:000176995400006 ER PT J AU Schulein, GJ Tischler, MB Mansur, MH Rosen, A AF Schulein, GJ Tischler, MB Mansur, MH Rosen, A TI Technical note validation of cross-coupling modeling improvements for UH-60 flight mechanics simulations SO JOURNAL OF THE AMERICAN HELICOPTER SOCIETY LA English DT Article ID IDENTIFICATION; DYNAMICS C1 San Jose State Univ, Ames Res Ctr, Moffett Field, CA 94035 USA. USA, Aeroflightdynam Directorate, AMCOM, Ames Res Ctr, Moffett Field, CA 94035 USA. Raytheon ITSS, Ames Res Ctr, Moffett Field, CA 94035 USA. Technion Israel Inst Technol, Dept Aerosp Engn, IL-32000 Haifa, Israel. RP Schulein, GJ (reprint author), San Jose State Univ, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 17 TC 2 Z9 2 U1 0 U2 1 PU AMER HELICOPTER SOC INC PI ALEXANDRIA PA 217 N WASHINGTON ST, ALEXANDRIA, VA 22314 USA SN 0002-8711 J9 J AM HELICOPTER SOC JI J. Am. Helicopter Soc. PD JUL PY 2002 VL 47 IS 3 BP 209 EP 213 PG 5 WC Engineering, Aerospace SC Engineering GA 576GP UT WOS:000176995400007 ER PT J AU Barker, HW Marshak, A Szyrmer, W Trishchenko, A Blanchet, JP Li, Z AF Barker, HW Marshak, A Szyrmer, W Trishchenko, A Blanchet, JP Li, Z TI Inference of cloud optical depth from aircraft-based solar radiometric measurements SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID RADIATIVE-TRANSFER; ATMOSPHERIC RADIATION; VEGETATION; STRATOCUMULUS; ALBEDO; ABSORPTION; SATELLITE; DISTRIBUTIONS; THICKNESS; DYNAMICS AB A method is introduced for inferring cloud optical depth tau from solar radiometric measurements made on an aircraft at altitude z. It is assessed using simulated radiometric measurements produced by a 3D Monte Carlo algorithm acting on fields of broken boundary layer clouds generated from Landsat imagery and a cloud-resolving model. The method uses upwelling flux and downwelling zenith radiance measured at two solar wavelengths where atmospheric optical properties above z are very similar but optical properties of the surface-atmosphere system below z differ. This enables estimation of cloud reflectance into nadir for upwelling diffuse flux and, finally, tau above z. An approximate one-dimensional radiative Green's function is used to roughly account for horizontal transport of photons in all, even broken, clouds. This method is compared to its surface-based counterpart and shown to be superior. Most notably, the aircraft-based approach deals easily with inhomogeneous land surfaces, is less susceptible to poor sampling, and need not account for aerosol below z. The algorithm appears as though it will have little difficulty inferring high-resolution time series of tau less than or equal to 40 for most (single layer) clouds. For larger values of t, biases emerge; particularly, underestimation for the statistically infrequent interiors of cumuliform clouds as photon leakage through cloud sides is not addressed. For the cumuliform and stratiform clouds used here, mean bias errors for retrieved tau are similar to1 (or similar to15%) and similar to0.3 (or similar to3%), respectively. For stratiform clouds with textured bases, performance is likely to improve slightly for flights just up from mean cloud base. C1 Environm Canada, Downsview, ON, Canada. JCET, UMBC, Greenbelt, MD USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Montreal, Montreal, PQ, Canada. Canada Ctr Remote Sensing, Ottawa, ON K1A OY7, Canada. Univ Maryland, College Pk, MD 20742 USA. RP Barker, HW (reprint author), Meteorol Serv Canada, Cloud Phys Res Div ARMP, 4905 Dufferin St, Downsview, ON M3H 5T4, Canada. RI Marshak, Alexander/D-5671-2012; Li, Zhanqing/F-4424-2010 OI Li, Zhanqing/0000-0001-6737-382X NR 39 TC 11 Z9 11 U1 0 U2 1 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 JUL PY 2002 VL 59 IS 13 BP 2093 EP 2111 DI 10.1175/1520-0469(2002)059<2093:IOCODF>2.0.CO;2 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 555WR UT WOS:000175816700004 ER PT J AU Wang, Z Sassen, K AF Wang, Z Sassen, K TI Cirrus cloud microphysical property retrieval using lidar and radar measurements. Part II: Midlatitude cirrus microphysical and radiative properties SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID GENERAL-CIRCULATION MODEL; BACKSCATTER PROFILES; CLIMATE FEEDBACK; RAMAN LIDAR; PARAMETERIZATION; EXTINCTION; FACILITY; SENSITIVITY; TEMPERATURE; LIQUID AB The lidar-radar algorithm described in Part I of this set of papers is applied to similar to1000 h of Raman lidar and millimeter wave cloud radar (MMCR) data collected at the Atmospheric Radiation Measurement program Southern Great Plains Clouds and Radiation Testbed site in Oklahoma during the period from November 1996 to November 2000. The resulting statistics of cirrus microphysical and radiative properties show that most cirrus clouds are optically thin (mean optical depth of 0.58 with a standard deviation of 0.67) with low ice water path (mean 12.19 g m(-2) with a standard deviation of 19.0). The seasonal changes of cirrus properties are relatively small except for the general effective radius (D-ge). Strong temperature dependencies of ice water content, D-ge, and extinction coefficients are found in the dataset, which are well described by second-order polynomial functions. The temperature and thickness dependencies of the cirrus properties are studied in detail, providing information useful in the validation and improvement of cirrus parameterizations in general circulation models. The limitations of the MMCR for cirrus detection are also considered through comparisons with results from the Raman lidar, which show that the MMCR fails to detect most thin cirrus with tau less than or equal to 0.1 and consistently underestimates physical cloud thickness. Comparisons with available data describing cirrus microphysical and radiative properties are made, and an improved cirrus particle extinction coefficient parameterization based on the combined lidar-radar approach is offered. C1 Univ Utah, Dept Meteorol, Salt Lake City, UT 84112 USA. RP Wang, Z (reprint author), NASA, Goddard Space Flight Ctr, GEST Ctr, Mail Code 912,Bldg 33,Rm A417, Greenbelt, MD 20771 USA. RI Wang, Zhien/F-4857-2011 NR 28 TC 58 Z9 60 U1 1 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD JUL PY 2002 VL 59 IS 14 BP 2291 EP 2302 DI 10.1175/1520-0469(2002)059<2291:CCMPRU>2.0.CO;2 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 564KA UT WOS:000176312500009 ER PT J AU Axenson, TJ Barnes, NP Reichle, DJ Koehler, EE AF Axenson, TJ Barnes, NP Reichle, DJ Koehler, EE TI High-energy Q-switched 0.946-mu m solid-state diode pumped laser SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article ID ND-YAG LASER AB Designing a high-energy Q-switched all-solid-state laser operating on the quasi-four-level 0.946-mum transition of Nd:YAG is quite challenging because of intense competition from the high-gain 1.064-mum transition. We have achieved such a laser by implementing an innovative resonator design, augmented by specialty coatings. Utilizing this approach, we obtained >75 mJ of Q-switched TEM00 mode energy in an all-solid-state diode pumped laser, a factor of 22 times more energy per pulse than any published data have reported. (C) 2002 Optical Society of America. C1 Sci & Technol Corp, Hampton, VA 23666 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Axenson, TJ (reprint author), Sci & Technol Corp, 10 Basil Sawyer Dr, Hampton, VA 23666 USA. NR 11 TC 22 Z9 22 U1 0 U2 3 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0740-3224 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD JUL PY 2002 VL 19 IS 7 BP 1535 EP 1538 DI 10.1364/JOSAB.19.001535 PG 4 WC Optics SC Optics GA 573FG UT WOS:000176818200005 ER PT J AU Simpson, JE Garimella, SV de Groh, HC AF Simpson, JE Garimella, SV de Groh, HC TI Experimental and numerical investigation of the Bridgman growth of a transparent material SO JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER LA English DT Article ID CRYSTAL-GROWTH; DIRECTIONAL SOLIDIFICATION; CELLULAR SPACINGS; BINARY MIXTURE; CONVECTION; SEGREGATION; SIMULATION; ALLOYS; FLOW AB A combined experimental and numerical study of the horizontal Bridgman growth of pure succinonitrile has been performed. The effect of convection on interface propagation and shape is quantified and discussed. Measurements were obtained both under conditions of no-growth and for a 40-mum/s growth rate. The quantities measured include interface shape and location, melt velocities, and temperature boundary conditions on the ampoule exterior. The melt velocities were measured using a new technique that employed digital cameras to image the locations of seed particles in the melt. The growth front was stable and nondendritic but was significantly distorted by the influence of convection in the melt and, for the growth case, by the moving temperature boundary conditions along the ampoule. Both two- and three-dimensional numerical simulations of the growth process were performed. Temperatures throughout the phase-change material and ampoule, as well as melt velocities, were obtained from the simulations. The predicted interface shapes and melt velocities agree well with experimental results. Two different numerical algorithms were used; the utility of each for simulating phase-change problems is discussed. This combined experimental and numerical study provides a database for the validation of phase-change numerical models, in addition to furnishing detailed information about the influence of convection on the Bridgman growth process. In ongoing work, the computer models presented are being used to simulate alloy solidification problems. C1 Purdue Univ, Sch Mech Engn, W Lafayette, IN 47907 USA. NASA, John H Glenn Res Ctr, Micrograv Sci Div, Cleveland, OH 44135 USA. RP Simpson, JE (reprint author), Purdue Univ, Sch Mech Engn, W Lafayette, IN 47907 USA. RI Garimella, Suresh/A-1286-2013 OI Garimella, Suresh/0000-0003-1421-2912 NR 29 TC 13 Z9 13 U1 0 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0887-8722 J9 J THERMOPHYS HEAT TR JI J. Thermophys. Heat Transf. PD JUL-SEP PY 2002 VL 16 IS 3 BP 324 EP 335 DI 10.2514/2.6709 PG 12 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA 575EU UT WOS:000176934400005 ER PT J AU Qiu, DM Dhir, VK Chao, D Hasan, MM Neumann, E Yee, G Birchenough, A AF Qiu, DM Dhir, VK Chao, D Hasan, MM Neumann, E Yee, G Birchenough, A TI Single-bubble dynamics during pool boiling under low gravity conditions SO JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER LA English DT Article ID SHEAR-FLOW; MICROGRAVITY; SURFACE; LIFT; HEAT AB Results of an experimental study on growth and detachment mechanisms of a single bubble on a heated surface conducted during the parabola flights of the KC-135 aircraft are described. An artificial cylindrical cavity 10 mum in diameter was etched in the center of a silicon wafer. The wafer was heated on the back side, and the wall superheat was controlled. Degassed distilled water was used as the test liquid. Bubble growth time, bubble size and shape from nucleation to liftoff were measured under subcooled and saturation conditions at system pressures varying from 0.101 to 0.115 MPa. The wall superheats were varied from 2.5 to 8.0degreesC. Significantly larger bubble diameters and longer bubble growth periods than those at Earth normal gravity were measured. Bubble diameters as large as 20 mm at liftoff were observed as opposed to about 2.5 mm at Earth normal gravity. Consistent with results of numerical simulations, it is found that for the same wall superheat and liquid subcooling the bubble liftoff diameter can be approximately related to the gravity level through the relation D-d proportional to g(-0.5) and the growth period as t(g) proportional to g(-1.05). The effect of wall superheat and liquid subcooling on bubble liftoff diameter is found to be small. However, the growth periods are found to be very sensitive to liquid subcooling at a given wall superheat. Small accelerations along the heater surface can lead to sliding motion of the bubble prior to liftoff. At the same gravitational acceleration the liftoff diameter of sliding bubbles is smaller than that of nonsliding bubbles. C1 Univ Calif Los Angeles, Micrograv Sci Div, Los Angeles, CA 90095 USA. NASA, John H Glenn Res Ctr, Micrograv Sci Div, Cleveland, OH 44135 USA. NASA, John H Glenn Res Ctr, Facil & Test Engn Div, Cleveland, OH 44135 USA. RP Qiu, DM (reprint author), Velocys Inc, Columbus, OH 43017 USA. NR 20 TC 27 Z9 29 U1 2 U2 13 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0887-8722 J9 J THERMOPHYS HEAT TR JI J. Thermophys. Heat Transf. PD JUL-SEP PY 2002 VL 16 IS 3 BP 336 EP 345 DI 10.2514/2.6710 PG 10 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA 575EU UT WOS:000176934400006 ER PT J AU Dulchavsky, SA Henry, SE Moed, BR Diebel, LN Marshburn, T Hamilton, DR Logan, J Kirkpatrick, AW Williams, DR AF Dulchavsky, SA Henry, SE Moed, BR Diebel, LN Marshburn, T Hamilton, DR Logan, J Kirkpatrick, AW Williams, DR TI Advanced ultrasonic diagnosis of extremity trauma: The FASTER examination SO JOURNAL OF TRAUMA-INJURY INFECTION AND CRITICAL CARE LA English DT Article DE fracture; ultrasound; space medicine; soft tissue injury ID SONOGRAPHIC DETECTION; THORACIC ULTRASOUND; FRACTURES; PNEUMOTHORAX AB Background: Ultrasound is of proven accuracy in abdominal and thoracic trauma and may be useful for diagnosing extremity injury in situations where radiography is not available such as military and space applications. We prospectively evaluated the utility of extremity ultrasound performed by trained, nonphysician personnel in patients with extremity trauma to simulate remote aerospace or military applications. Methods: Patients with extremity trauma were identified by history, physical examination, and radiographic studies. Ultrasound examination was performed bilaterally by nonphysician personnel, blinded to radiographic results, with a portable ultrasound device using a 10- to 5-MHz linear probe. Images were video-recorded for later analysis against radiography by Fisher's exact test. Results: There were 158 examinations performed in 95 patients. The average time of examination was 4 minutes. Ultrasound accurately diagnosed extremity injury in 94% of patients with no false-positive examinations; accuracy was greater in midshaft locations and least in the metacarpal/metatarsals. Soft tissue/tendon injury was readily visualized. Conclusion; Extremity ultrasound can be performed quickly and accurately by nonphysician personnel with excellent accuracy. Pulmonary ultrasound appears promising; blinded verification of the utility of ultrasound in patients with extremity injury should be performed to determine whether extremity and respiratory evaluation should be added to the FAST examination (the FASTER examination) and to verify the technique in remote locations such as military and aerospace applications. C1 Vancouver Gen Hosp, Vancouver, BC, Canada. Wyle Labs, Houston, TX USA. NASA, Lyndon B Johnson Space Ctr, Life Sci Directorate, Houston, TX 77058 USA. Wayne State Univ, Sch Med, Dept Orthoped Surg, Detroit, MI USA. Wayne State Univ, Sch Med, Dept Surg, Detroit, MI USA. RP Dulchavsky, SA (reprint author), Detroit Receiving Hosp & Univ Hlth Ctr, Dept Surg, 4201 St Antoine, Detroit, MI 48201 USA. NR 20 TC 42 Z9 42 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0022-5282 J9 J TRAUMA JI J. Trauma-Injury Infect. Crit. Care PD JUL PY 2002 VL 53 IS 1 BP 28 EP 32 DI 10.1097/00005373-200207000-00006 PG 5 WC Critical Care Medicine; Surgery SC General & Internal Medicine; Surgery GA 573BR UT WOS:000176809900008 PM 12131385 ER PT J AU Celestina, ML Adamczyk, JJ Rubin, SG AF Celestina, ML Adamczyk, JJ Rubin, SG TI A solution strategy based on segmented domain decomposition multigrid for turbomachinery flows SO JOURNAL OF TURBOMACHINERY-TRANSACTIONS OF THE ASME LA English DT Article; Proceedings Paper CT 46th International Congress and Exhibition on Gas Turbines and Aeroengines CY JUN 04-07, 2001 CL NEW ORLEANS, LOUISIANA AB A Segmented Domain Decomposition Multigrid (SDDMG) procedure was developed for viscous flow problems as they apply to turbomachinery flows. The procedure divides the computational domain into a coarse mesh comprised of uniformly spaced cells. To resolve smaller length scales such as the viscous layer near a surface, segments of the coarse mesh are subdivided into a finer mesh. This is repeated until adequate resolution of the smallest relevant length scale is obtained. Multigrid is used to communicate information between the different grid levels [1]. To test the procedure, simulation results will be presented for a compressor and turbine cascade. These simulations are intended to show the ability of the present method to generate grid independent solutions. Comparisons with data will also be presented. These comparisons will further demonstrate the usefulness of the present work-for they allow an estimate of the accuracy of the flow modeling equations independent of error attributed to numerical discretization. C1 AP Solut Inc, Cleveland, OH 44135 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Univ Cincinnati, Cincinnati, OH 45221 USA. RP Celestina, ML (reprint author), AP Solut Inc, Cleveland, OH 44135 USA. NR 14 TC 0 Z9 0 U1 1 U2 1 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 0889-504X J9 J TURBOMACH JI J. Turbomach.-Trans. ASME PD JUL PY 2002 VL 124 IS 3 BP 341 EP 350 DI 10.1115/1.1451085 PG 10 WC Engineering, Mechanical SC Engineering GA 576PK UT WOS:000177013500003 ER PT J AU Roberts, WB Armin, A Kassaseya, G Suder, KL Thorp, SA Strazisar, AJ AF Roberts, WB Armin, A Kassaseya, G Suder, KL Thorp, SA Strazisar, AJ TI The effect of variable chord length on transonic axial rotor performance SO JOURNAL OF TURBOMACHINERY-TRANSACTIONS OF THE ASME LA English DT Article; Proceedings Paper CT 46th International Congress and Exhibition on Gas Turbines and Aeroengines CY JUN 04-07, 2001 CL NEW ORLEANS, LOUISIANA DE axial compressor; variable chord; blade recontour; performance restoration AB Aircraft fan and compressor blade leading edges suffer from atmospheric particulate erosion that reduces aerodynamic performance. Recontouring the blade leading edge region can restore blade performance. This process typically results in blades of varying chord length. The question therefore arises as to whet her performance of refurbished fans and compressors could be further improved if blades of varying chord length are installed into the disk in a certain order. To investigate this issue the aerodynamic performance of a transonic compressor rotor operating with blades of varying chord length was measured in back-to-back compressor test rig entries. One half of the rotor blades were the full nominal chord length while the remaining half of the blades were cut back at the leading edge to 95% of chord length and recontoured. The rotor aerodynamic performance was measured at 100, 80, and 60% of design speed for three blade installation configurations: the disk and short-chord blades in half of the disk: four nominal-chord blades in half of alternating quadrants of nominal-chord and short-chord blades; nominal-chord and short-chord blades alternating around the disk. No significant difference in performance was found between configurations, indicating that blade chord variation is not important to aerodynamic performance above the stall chord limit if leading edges have the same shape. The stall chord limit for most civil aviation turbofan engines is between 94-96% of nominal (new) blade chord. C1 Airfoil Management Co, Compton, CA 90220 USA. Airfoil Technol Int, Compton, CA 90220 USA. NASA, Glenn Res Ctr, Cleveland, OH USA. RP Roberts, WB (reprint author), Airfoil Management Co, Compton, CA 90220 USA. NR 13 TC 5 Z9 5 U1 0 U2 0 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 0889-504X J9 J TURBOMACH JI J. Turbomach.-Trans. ASME PD JUL PY 2002 VL 124 IS 3 BP 351 EP 357 DI 10.1115/1.1459734 PG 7 WC Engineering, Mechanical SC Engineering GA 576PK UT WOS:000177013500004 ER PT J AU Maerz, J Hah, C Neise, W AF Maerz, J Hah, C Neise, W TI Closure to "Discussion of 'An experimental and numerical investigation into the mechanisms of rotating instability'" (2002, ASME J. Turbomach., 124) SO JOURNAL OF TURBOMACHINERY-TRANSACTIONS OF THE ASME LA English DT Editorial Material C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Maerz, J (reprint author), NASA, Glenn Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 0889-504X J9 J TURBOMACH JI J. Turbomach.-Trans. ASME PD JUL PY 2002 VL 124 IS 3 BP 375 EP 375 DI 10.1115/1.1460917 PG 1 WC Engineering, Mechanical SC Engineering GA 576PK UT WOS:000177013500008 ER PT J AU Whitacre, JF Yalisove, SM Bilello, JC AF Whitacre, JF Yalisove, SM Bilello, JC TI Real-time/in situ diffraction study of phase and microstructural evolution in sputtered beta-Ta/Ta2O5 films (vol 19, 2910, 2001) SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Correction C1 Univ Michigan, Dept Mat Sci & Engn, Ann Arbor, MI 48109 USA. RP Whitacre, JF (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 1 TC 0 Z9 0 U1 1 U2 1 PU A V S AMER INST PHYSICS PI MELVILLE PA STE 1 NO 1, 2 HUNTINGTON QUADRANGLE, MELVILLE, NY 11747-4502 USA SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD JUL-AUG PY 2002 VL 20 IS 4 BP 1505 EP 1505 DI 10.1116/1.1477419 PG 1 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 574WL UT WOS:000176912500053 ER PT J AU DellaCorte, C AF DellaCorte, C TI Are we speaking your language? 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 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 JUL PY 2002 VL 58 IS 7 BP 3 EP 3 PG 1 WC Engineering, Mechanical SC Engineering GA 578ML UT WOS:000177121400001 ER PT J AU Baaklini, GY Smith, K Raulerson, D Gyekenyesi, AL Sawicki, JT Brasche, L AF Baaklini, GY Smith, K Raulerson, D Gyekenyesi, AL Sawicki, JT Brasche, L TI Tools for engine diagnostics under the NASA Aviation Safety Program SO MATERIALS EVALUATION LA English DT Article DE aviation safety; wireless eddy current; thermal acoustics; modal norms; rotor dynamics; nonlinear acoustics; fracture mechanics; damage mechanics; safe life design; onwing nondestructive inspection; damage detection; crack detection ID STRUCTURAL DAMAGE DETECTION; MODEL AB Tools for Engine Diagnostics, is a major task in the Propulsion System Health Management area of the Single Aircraft Accident Prevention project under the NASA Aviation Safety Program. The major goal of the safety program to reduce fatal aircraft accidents by 807, within 10 years and by 90% within 25 years. The Propulsion System Health Management goal is to eliminate propulsion system malfunctions as a primary or contributing factor in the cause of aircraft accidents. The purpose of Tools for Engine Diagnostics, a two year old task program, is to establish and improve the tools for engine diagnostics and prognostics for measuring deformation and damage of rotating engine components at the ground level and for intermittent or continuous monitoring in the onwing engine environment. In this work, nondestructive inspection based technology is combined with model dependent disk spin experimental simulation systems, like finite element modeling and modal norms, to monitor and predict rotor damage in real time. Fracture mechanics time dependent fatigue crack growth and damage mechanics based life estimation are being developed and their potential use is investigated. In addition, wireless eddy current and advanced acoustics are being developed for onwing and just in time nondestructive engine inspection to provide deeper access and higher sensitivity that extends onwing capabilities and improves inspection readiness. In the long run, these methods can establish the base for prognostic sensing, while the engine is running, without any overt action like inspection. This damage detection strategy includes experimentally acquired vibration, eddy current and capacitance based displacement measurements and analytically computed finite element modeling, modal norms and conventional rotor dynamics based models of well defined damage and critical mass imbalances in rotating disks and rotors. C1 NASA, Glenn Res Ctr, Brookpark, OH 44135 USA. United Technol Corp, Pratt & Whitney, E Hartford, CT 06108 USA. Pratt & Whitney, Mat & Proc Engn, E Hartford, CT 06108 USA. Ohio Aerosp Inst, Cleveland, OH 44142 USA. Cleveland State Univ, Cleveland, OH 44115 USA. Iowa State Univ, Ames, IA 50011 USA. RP Baaklini, GY (reprint author), NASA, Glenn Res Ctr, 21000 Brookpk Rd,MS6-1, Brookpark, OH 44135 USA. NR 27 TC 4 Z9 4 U1 1 U2 7 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 JUL PY 2002 VL 60 IS 7 BP 878 EP 883 PG 6 WC Materials Science, Characterization & Testing SC Materials Science GA 570FL UT WOS:000176648200013 ER PT J AU Smialek, JL Morscher, GN AF Smialek, JL Morscher, GN TI Delayed alumina scale spallation on Rene'N5+Y: moisture effects and acoustic emission SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article DE superalloy; spallation; oxidation; acoustic emission ID SPALLING FAILURE; OXIDE SCALES; OXIDATION; PROPAGATION; SUPERALLOY; INTERFACES; BEHAVIOR; SULFUR; METAL; ALPHA-AL2O3 AB The single crystal superalloy Rene'N5 (with or without Y-doping and hydrogen annealing) was cyclically oxidized at 1150 degreesC for 1000 h. After considerable scale growth (greater than or equal to 500 h), even the adherent alumina scales formed on Y-doped samples exhibited delayed interfacial spallation during subsequent water immersion tests. performed up to I year after oxidation. Spallation was characterized by weight loss, the amount of spalled area and acoustic emission response. Hydrogen annealing (prior to oxidation) reduced spallation both before and after immersion, but without measurably reducing the bulk sulfur content of the Y-doped alloys. The duration and frequency of sequential. co-located acoustic emission events implied an interfacial crack growth rate at least 10(-3) ms(-1). but possibly higher than 10(2) ms(-1). This is much greater than classic moisture-assisted slow crack growth rates in bulk alumina (10 (6) to 10 (-) (3) m s (- 1)), which may still have occurred undetected by acoustic emission. An alternative failure sequence is proposed: an incubation process for preferential moisture ingress leads to a local decrease in interfacial toughness, thus allowing fast fracture driven by stored strain energy. Crown Copyright (C) 2002 Published by Elsevier Science B.V. All rights reserved. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Smialek, JL (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. EM james.l.smialck@grs.nasa.gov NR 32 TC 32 Z9 33 U1 0 U2 5 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 JUL PY 2002 VL 332 IS 1-2 BP 11 EP 24 AR PII S0921-5093(01)01712-9 DI 10.1016/S0921-5093(01)01712-9 PG 14 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 563VX UT WOS:000176260800002 ER PT J AU de Arellano-Lopez, AR Varela-Feria, FM Martiinez-Fernandez, J Singh, M AF de Arellano-Lopez, AR Varela-Feria, FM Martiinez-Fernandez, J Singh, M TI Compressive creep of silicon nitride with different secondary phase compositions SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article DE silicon nitride; compression; creep; microstructure ID SOLUTION-PRECIPITATION CREEP; ROD-SHAPED GRAINS; TENSILE CREEP; VISCOUS-FLOW; CERAMICS; DEFORMATION; SI3N4; MICROSTRUCTURE; MECHANISMS; BEHAVIOR AB Compressive creep has been studied in several commercial and experimental grades of Si(3)N(4), with similar microstructures but different grain boundary phase compositions. The experiments took place at 1400 and 1500 degreesC in static argon atmosphere. The creep rates at a given temperature showed more than one order of magnitude of grade to grade variability. However, all types of Si(3)N(4) appear to deform by the same mechanism. When analyzed by a classic power-law equation for the creep parameters. n approximate to 1 for all grades, while Q varied from 444 to 951 kJ mol(-1). A solution-reprecipitation creep mechanism is considered compatible with these results. (C) 2002 Elsevier Science B.V. All rights reserved. C1 Univ Seville, Dept Fis Mat Condensada, Seville 41080, Spain. NASA Glenn Res Ctr, QSS Grp Inc, Cleveland, OH 44135 USA. RP de Arellano-Lopez, AR (reprint author), Univ Seville, Dept Fis Mat Condensada, POB 1065, Seville 41080, Spain. EM ramirez@cica.es RI MARTINEZ FERNANDEZ, JULIAN/K-1826-2012; OI MARTINEZ FERNANDEZ, JULIAN/0000-0002-1199-6638; R. de Arellano Lopez, Antonio/0000-0002-7443-0244 NR 32 TC 2 Z9 3 U1 0 U2 3 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 JUL PY 2002 VL 332 IS 1-2 BP 295 EP 300 AR PII S0921-5093(01)01749-X DI 10.1016/S0921-5093(01)01749-X PG 6 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 563VX UT WOS:000176260800039 ER PT J AU Khan, FA Zhou, L Kumar, V Adesida, I Okojie, R AF Khan, FA Zhou, L Kumar, V Adesida, I Okojie, R TI High rate etching of AlN using BCl3/Cl-2/Ar inductively coupled plasma SO MATERIALS SCIENCE AND ENGINEERING B-SOLID STATE MATERIALS FOR ADVANCED TECHNOLOGY LA English DT Article DE AlN; ICP-RIE; etching ID NITRIDES; GAN AB Inductively-coupled-plasma reactive ion etching of AlN was investigated using BCl3/Cl-2/Ar gas chemistry. AlN etch rates were studied as a function of substrate bias voltage (-150 to -400 V), ICP coil power (200-900 W) and chamber pressure (2-10 mT). Using an electroplated Ni mask, up to 50 mum deep AlN structures were etched. This is the first demonstration of deep etching of AlN at high etch rates using inductively-coupled-plasma. The results reported in this study can be used for bulk micro-machining AlN substrates. (C) 2002 Published by Elsevier Science B.V. C1 Univ Illinois, Dept Elect & Comp Engn, Urbana, IL 61801 USA. Univ Illinois, Microelect Lab, Urbana, IL 61801 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Khan, FA (reprint author), Univ Illinois, Dept Elect & Comp Engn, 1406 W Green St, Urbana, IL 61801 USA. NR 6 TC 25 Z9 25 U1 1 U2 12 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 JUL 1 PY 2002 VL 95 IS 1 BP 51 EP 54 AR PII S0921-5107(02)00160-5 DI 10.1016/S0921-5107(02)00160-5 PG 4 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA 577XB UT WOS:000177087100010 ER PT J AU Shyam, A Padula, SA Marras, SI Milligan, WW AF Shyam, A Padula, SA Marras, SI Milligan, WW TI Fatigue-crack-propagation thresholds in a nickel-base superalloy at high frequencies and temperatures SO METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Article ID FRACTURE SURFACE-ROUGHNESS; HIGH-CYCLE FATIGUE; TI-6AL-4V ALLOY; BEHAVIOR; GROWTH; MICROSTRUCTURE; 650-DEGREES-C; DEFORMATION; DEFLECTION AB Fatigue-crack-propagation (FCP) tests were conducted on the powder metallurgy nickel-base super-alloy KM4 at temperatures of 20 degreesC, 550 degreesC, and 650 degreesC. Two different heat treatments were investigated, one yielding a relatively coarse grain size of 55 mum and another yielding a fine grain size of 6 mum. Tests were conducted at 100 Hz and 1000 Hz and at load ratios between 0.3 and 0.7. In the Paris regime, trends observed at high frequencies for KM4 were identical to those observed by earlier investigators at lower frequencies: coarse grains. low load ratios, low temperatures, and higher frequencies generally resulted in lower crack-propagation rates. However, in contrast to the Paris-regime behavior, thresholds were a complicated function of microstructure, load ratio, temperature, and frequency, and the only variable that resulted in a consistent trend in threshold was the load ratio. For example, thresholds increased from 100 to 1000 Hz for the fine-grained material at 550 degreesC, but decreased with the same frequency variation at 650 degreesC. One reason for this complexity was a change to intergranular fracture in the fine-grained microstructure at 650 degreesC, which was beneficial for high-frequency thresholds. Higher load ratios and lower frequencies promoted intergranular fracture. However, not all of the complexity could be explained by changing fracture mechanisms. Scanning electron microscope (SEM) stereofractography was utilized to determine quantitative measures of fracture-surface roughness. The most useful quantitative measure was found to be the standard deviation of the fracture-surface height, which is a physically meaningful length parameter and which corresponded to about half the grain size during room-temperature fatigue at near-threshold DeltaK levels. The roughness of the fracture surface was found to increase as the load ratio was increased for both microstructures. For the coarse-grained microstructure, there was a direct correlation between fracture-surface roughness and FCP threshold over the entire range of temperatures, frequencies, and load ratios. However, measurements of closure loads indicated that roughness-induced closure was not the sole reason for the varying FCP thresholds. C1 Michigan Technol Univ, Dept Mat Sci & Engn, Houghton, MI 49931 USA. NASA, Clenn Res Ctr, Cleveland, OH 44135 USA. Michigan Technol Univ, Dept Mech Engn & Engn Mech, Houghton, MI 49931 USA. RP Shyam, A (reprint author), Michigan Technol Univ, Dept Mat Sci & Engn, Houghton, MI 49931 USA. OI Shyam, Amit/0000-0002-6722-4709 NR 33 TC 4 Z9 5 U1 1 U2 11 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086 USA SN 1073-5623 J9 METALL MATER TRANS A JI Metall. Mater. Trans. A-Phys. Metall. Mater. Sci. PD JUL PY 2002 VL 33 IS 7 BP 1949 EP 1962 DI 10.1007/s11661-002-0028-2 PG 14 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 568FW UT WOS:000176532600008 ER PT J AU Wasilewski, P Acuna, MH Kletetschka, G AF Wasilewski, P Acuna, MH Kletetschka, G TI 433 Eros: Problems with the meteorite magnetism record in attempting an asteroid match SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID ORDINARY CHONDRITES; SOLAR-SYSTEM; IRON; METAMORPHISM; PHASES; METAL; FIELD AB The magnetometer experiment (MAG) onboard the Near-Earth Asteroid Rendezvous (NEAR)-Shoemaker spacecraft detected no global scale magnetization and established a maximum magnetization of 2.1 x 10(-6) Am-2 kg(-1) for asteroid 433 Eros. This is in sharp contrast with the estimated magnetization of other S-class asteroids (Gaspra, similar to2.4 x 10(-2) Amt(2) kg(-1); Braille, similar to2.8 x 10(-2) Am-2 kg(-1)) and is below published values for all types of ordinary chondrites. This includes the L/LL types considered to most closely match 433 Eros based on preliminary interpretations of NEAR remote geochemical experiments. The ordinary chondrite meteorite magnetization intensity data was reviewed in order to assess the reasonableness of an asteroid-meteorite match based on magnetic property measurements. Natural remanent magnetization (NRM) intensities for the ordinary chondrite meteorites show at least a 2 order of magnitude range within each of the H, L, and LL groups, all well above the 2.1 x 10(-6) Amt(2) kg(-1) level for 433 Eros. The REM values (ratio of the NRM to the SIRM (saturation remanent magnetization)) range over 3 orders of magnitude for all chondrite groups indicating no clear relationship between NRM and the amount of magnetic material. Levels of magnetic noise in chondrite meteorites can be as much as 70% or more of the NRM. Consequently, published values of the NRM should be considered suspect unless careful evaluation of the noise sources is done. NASA Goddard SFC studies of per unit mass intensities in large (>10 000 g) and small (down to <1 g) samples from the same meteorite demonstrate magnetic intensity decreases as size increases. This would appear to be explained by demagnetization due to magnetic vector randomness at unknown scale sizes in the larger samples. This would then argue for some level of demagnetization of large objects such as an asteroid. The possibility that 433 Eros is an LL chondrite cannot be discounted. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. Catholic Univ Amer, Washington, DC 20064 USA. RP Wasilewski, P (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. RI Kletetschka, Gunther/C-9996-2011 OI Kletetschka, Gunther/0000-0002-0645-9037 NR 37 TC 18 Z9 19 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 JUL PY 2002 VL 37 IS 7 BP 937 EP 950 PG 14 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 579AA UT WOS:000177152200004 ER PT J AU Herd, CDK Schwandt, CS Jones, JH Papike, JJ AF Herd, CDK Schwandt, CS Jones, JH Papike, JJ TI An experimental and petrographic investigation of Elephant Moraine 79001 lithology A: Implications for its petrogenesis and the partitioning of chromium and vanadium in a martian basalt SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID ORTHO-PYROXENE; SILICATE MELT; OLIVINE; SPINEL; LIQUID; METEORITE; ELEMENTS; MAGMAS; A79001 AB A composition approximating the lithology A groundmass of the Elephant Moraine (EET) 79001 martian basalt (Eg; McSween and Jarosewich, 1983) has been used to investigate the petrogenesis of the meteorite and the behavior of Cr and V at different oxygen fugacities. Crystallization experiments were carried out over a range of temperatures, and oxygen fugacities of either iron-wustite (IW) or IW + 2 (i.e., 1.5 log units below the quartz-fayalite-magnetite (QFM) buffer). Comparison of trace element concentrations (obtained by secondary ion mass spectrometry (SIMS) analysis) in experimental silicates with those of natural silicates supports the Fe-Ti oxide-derived oxygen fugacity of QFM -1.8 +/- 0.3 for this basalt (Herd et al., 2001). Experimental distribution coefficients, in conjunction with SIMS analyses of rims from the olivine and pyroxene xenocrysts in lithology A, as well as analyses of lithology A groundmass pigeonite cores, are used to calculate coexisting liquid concentrations of V and Cr. Liquid compositions derived from pigeonite xenocryst rims and groundmass pigeonite cores are similar, suggesting that the rims of orthopyroxene xenocrysts are overgrowths, which have not previously been accounted for when reconstructing the groundmass composition. This implies that the Eg composition requires modification. A similar exercise for the ferroan rims on olivine xenocrysts yields very different liquid compositions, indicating that these rims are not overgrowths but are part of the xenocryst assemblage. These results are shown to be consistent with the petrography of lithology A xenocrysts. C1 Lunar & Planetary Inst, Houston, TX 77058 USA. Lockheed Martin, Houston, TX 77058 USA. NASA, Astromat Res Off, SR, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Univ New Mexico, Dept Earth & Planetary Sci, Inst Meteorit, Albuquerque, NM 87131 USA. RP Herd, CDK (reprint author), Lunar & Planetary Inst, 3600 Bay Area Blvd, Houston, TX 77058 USA. NR 24 TC 16 Z9 16 U1 1 U2 5 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 BP 987 EP 1000 PG 14 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 579AA UT WOS:000177152200007 ER PT J AU Basu, A Wentworth, SJ McKay, DS AF Basu, A Wentworth, SJ McKay, DS TI Nanophase Fe-0 in agglutinitic glass and correlation of I-S/FeO with inverse grain size. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract C1 Indiana Univ, Bloomington, IN 47405 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 SU S BP A13 EP A13 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 581CZ UT WOS:000177274700010 ER PT J AU Bell, MS Schwandt, C Zolensky, ME Horz, F AF Bell, MS Schwandt, C Zolensky, ME Horz, F TI Experimental shock decomposition of siderite. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract C1 Univ Houston, Houston, TX 77004 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NR 6 TC 2 Z9 2 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 SU S BP A14 EP A14 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 581CZ UT WOS:000177274700012 ER PT J AU Benner, LAM Nolan, MC Black, GJ Giorgini, JD Margot, JL Pravec, P Ostro, SJ Jurgens, RF AF Benner, LAM Nolan, MC Black, GJ Giorgini, JD Margot, JL Pravec, P Ostro, SJ Jurgens, RF TI Radar images of asteroid 38071 (1999 GU3). SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Natl Astron & Ionosphere Ctr, Arecibo Observ, Arecibo, PR 00613 USA. NRAO, Green Bank, WV USA. CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. Acad Sci Czech Republ, Inst Astron, CS-25165 Ondrejov, Czech Republic. RI Margot, Jean-Luc/A-6154-2012; Pravec, Petr/G-9037-2014 OI Margot, Jean-Luc/0000-0001-9798-1797; NR 1 TC 1 Z9 1 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 SU S BP A15 EP A15 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 581CZ UT WOS:000177274700014 ER PT J AU Bogard, DD AF Bogard, DD TI Ar-39-Ar-40 ages and thermal histories of meteorite parent bodies. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 SU S BP A20 EP A20 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 581CZ UT WOS:000177274700024 ER PT J AU Boynton, WV Feldman, WC Mitrofanov, I Evans, LG Reedy, C Squyres, SW Starr, R Trombka, JI d'Uston, C Arnold, JR Englert, PAJ Metzger, AE Wanke, H Bruckner, J Drake, DM Shinohara, C Fellows, C Hamara, DK Harshman, K AF Boynton, WV Feldman, WC Mitrofanov, I Evans, LG Reedy, C Squyres, SW Starr, R Trombka, JI d'Uston, C Arnold, JR Englert, PAJ Metzger, AE Wanke, H Bruckner, J Drake, DM Shinohara, C Fellows, C Hamara, DK Harshman, K TI Early results of the Mars Odyssey gamma-ray spectrometer (GRS): Ice and other cool stuff. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract C1 Univ Arizona, Tucson, AZ 85721 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Space Res Inst, Moscow, Russia. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ New Mexico, Albuquerque, NM 87131 USA. Cornell Univ, Ithaca, NY 14853 USA. Univ Calif San Diego, San Diego, CA 92103 USA. Victoria Univ Wellington, Wellington, New Zealand. CALTECH, Jet Prop Lab, Pasadena, CA USA. Max Planck Inst Chem, D-55128 Mainz, Germany. NR 0 TC 1 Z9 1 U1 0 U2 1 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 SU S BP A21 EP A21 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 581CZ UT WOS:000177274700026 ER PT J AU Bradley, JP Dai, ZR Joswiak, D Brownlee, DE Hill, HGM Genge, MM AF Bradley, JP Dai, ZR Joswiak, D Brownlee, DE Hill, HGM Genge, MM TI Some diamonds may not be forever. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract ID INTERPLANETARY DUST PARTICLES; MINERALOGY C1 Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94551 USA. Georgia Inst Technol, Atlanta, GA 30332 USA. Univ Washington, Seattle, WA 98195 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Nat Hist Museum, London SW7 5BD, England. RI Dai, Zurong/E-6732-2010 NR 4 TC 0 Z9 0 U1 0 U2 1 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 SU S BP A21 EP A21 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 581CZ UT WOS:000177274700027 ER PT J AU Britt, DT Agee, C Allen, C Bada, JL Bell, JF Blaney, D Bradley, J Clark, B Durda, D Housen, K Kring, D McSween, H Robinson, M Thomas, P Young, E AF Britt, DT Agee, C Allen, C Bada, JL Bell, JF Blaney, D Bradley, J Clark, B Durda, D Housen, K Kring, D McSween, H Robinson, M Thomas, P Young, E TI The Gulliver mission: A short-cut to martian sample return. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract C1 Univ Tennessee, Dept Geol Sci, Knoxville, TN 37996 USA. NASA, JSC, Houston, TX USA. UCSD Scripps, San Diego, CA USA. Univ Hawaii, Honolulu, HI 96822 USA. NASA, JPL, Houston, TX USA. Univ Arizona, Tucson, AZ 85721 USA. Northwestern Univ, Evanston, IL 60208 USA. Cornell Univ, Ithaca, NY 14853 USA. Univ Calif Los Angeles, Los Angeles, CA 90024 USA. NR 1 TC 1 Z9 1 U1 0 U2 4 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 SU S BP A25 EP A25 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 581CZ UT WOS:000177274700035 ER PT J AU Chabot, NL Jones, JH AF Chabot, NL Jones, JH TI Parameterizing iron meteorite partitioning experiments. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract C1 Case Western Reserve Univ, Cleveland, OH 44106 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RI Chabot, Nancy/F-5384-2015 OI Chabot, Nancy/0000-0001-8628-3176 NR 1 TC 1 Z9 1 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 SU S BP A30 EP A30 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 581CZ UT WOS:000177274700044 ER PT J AU Chen, JH Papanastassiou, DA AF Chen, JH Papanastassiou, DA TI NTIMS determination of ruthenium isotopes. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract C1 CALTECH, GPS Div, Lunat Asylum, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, ESS Div, Pasadena, CA 91109 USA. NR 11 TC 1 Z9 1 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 SU S BP A31 EP A31 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 581CZ UT WOS:000177274700047 ER PT J AU Clemett, SJ Messenger, S Keller, LP Thomas-Keprta, KL McKay, DS AF Clemett, SJ Messenger, S Keller, LP Thomas-Keprta, KL McKay, DS TI Spatially resolved analysis of amines in interplanetary dust particles using fluorescent molecular probes. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract C1 Lockheed Martin, Houston, TX 77058 USA. Washington Univ, Space Sci Lab, St Louis, MO 63130 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NR 3 TC 2 Z9 2 U1 0 U2 1 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 SU S BP A36 EP A36 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 581CZ UT WOS:000177274700056 ER PT J AU Cole, KJ Sipiera, PP AF Cole, KJ Sipiera, PP TI Classification of ten recent meteorite finds from Dar al Gani, Libya. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract C1 Harper Coll, Schmitt Meteorite Res Grp, Palatine, IL 60067 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Mercer Univ, Dept Phys, Macon, GA 31207 USA. SaharaMet, La Terrasse, France. NR 3 TC 0 Z9 0 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 SU S BP A37 EP A37 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 581CZ UT WOS:000177274700059 ER PT J AU Fink, D Ma, P Herzog, GF Albrecht, A Garrison, DH Bogard, DD Reedy, RC Masarik, J AF Fink, D Ma, P Herzog, GF Albrecht, A Garrison, DH Bogard, DD Reedy, RC Masarik, J TI Be-10, Al-26, Cl-36, and non-spallogenic Ar-36 in the Norton County aubrite. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract ID HIGH FLUENCES; NEUTRONS C1 Australian Nucl Sci & Technol Org, Menai, NSW 2234, Australia. Rutgers State Univ, Dept Chem & Chem Biol, Piscataway, NJ 08854 USA. Swiss Fed Inst Tech, Inst Plant Sci, CH-8315 Lindau, Switzerland. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Univ New Mexico, Inst Meteorit, Albuquerque, NM 87131 USA. Comenius Univ, Dept Nucl Phys, SK-84248 Bratislava, Slovakia. RI fink, David/A-9518-2012 NR 7 TC 1 Z9 1 U1 0 U2 1 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 SU S BP A46 EP A46 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 581CZ UT WOS:000177274700077 ER PT J AU Garrison, D Bogard, D Takeda, H AF Garrison, D Bogard, D Takeda, H TI Old Ar-39-Ar-40 ages for two eucrites. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Chiba Inst Technol, Chiba 2750016, Japan. NR 5 TC 0 Z9 0 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 SU S BP A50 EP A50 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 581CZ UT WOS:000177274700085 ER PT J AU Golden, DC Ming, DW Zolensky, ME Lauer, HV Schwandt, CS Morris, RV Lofgren, GE McKay, GA AF Golden, DC Ming, DW Zolensky, ME Lauer, HV Schwandt, CS Morris, RV Lofgren, GE McKay, GA TI Morphology of magnetite formed via thermal decomposition of siderite: Implications for inorganic formation of magnetite in martian meteorite ALH84001. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract ID CRYSTALS C1 Hernandez Engn, Houston, TX 77058 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NR 6 TC 0 Z9 1 U1 0 U2 2 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 SU S BP A53 EP A53 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 581CZ UT WOS:000177274700090 ER PT J AU Herd, CDK Treiman, AH McKay, GA Shearer, CK AF Herd, CDK Treiman, AH McKay, GA Shearer, CK TI Implications of experimental lithium and boron partition coefficients for the petrogenesis of martian basalts. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract ID BERYLLIUM C1 Lunar & Planetary Inst, Houston, TX 77058 USA. NASA, Lyndon B Johnson Space Ctr, Astromat Res Off, Houston, TX 77058 USA. Univ New Mexico, Dept Earth & Planetary Sci, Inst Meteorit, Albuquerque, NM 87131 USA. NR 6 TC 3 Z9 3 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 SU S BP A62 EP A62 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 581CZ UT WOS:000177274700108 ER PT J AU Hoffman, EJ Denalli, CA Hill, HGH Nuth, JA AF Hoffman, EJ Denalli, CA Hill, HGH Nuth, JA TI Aqueous alteration of circumstellar silicate dust analogs: Crystallization of mineral products. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract C1 NASA, Goddard Space Flight Ctr, Astrochem Branch, Greenbelt, MD 20771 USA. Morgan State Univ, Dept Phys, Baltimore, MD 21251 USA. RI Nuth, Joseph/E-7085-2012 NR 3 TC 2 Z9 2 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 SU S BP A64 EP A64 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 581CZ UT WOS:000177274700111 ER PT J AU Keller, LP Messenger, S Flynn, GJ Wirick, S Jacobsen, C AF Keller, LP Messenger, S Flynn, GJ Wirick, S Jacobsen, C TI Organic characteristics of D-rich and D-poor cluster IDPs. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract ID INTERPLANETARY DUST PARTICLES; IDENTIFICATION C1 SUNY Stony Brook, Dept Phys, Stony Brook, NY 11794 USA. SUNY Coll Plattsburgh, Dept Phys, Plattsburgh, NY 12901 USA. Washington Univ, Dept Phys, St Louis, MO 63130 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RI Jacobsen, Chris/E-2827-2015 OI Jacobsen, Chris/0000-0001-8562-0353 NR 4 TC 0 Z9 0 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 SU S BP A76 EP A76 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 581CZ UT WOS:000177274700134 ER PT J AU Koizumi, E Mikouchi, T McKay, G Le, L Schwandt, C Monkawa, A Miyamoto, M AF Koizumi, E Mikouchi, T McKay, G Le, L Schwandt, C Monkawa, A Miyamoto, M TI Comparative cooling experiments of Queen Alexandra range 94201 basaltic shergottite under reducing and oxidizing conditions. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract ID PYROXENES C1 Lockhee Martin, Houston, TX 77058 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Univ Tokyo, Dept Earth & Planet Sci, Tokyo 1130033, Japan. NR 5 TC 0 Z9 0 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 SU S BP A80 EP A80 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 581CZ UT WOS:000177274700142 ER PT J AU Liu, YZ Nyquist, LE Wiesmann, H Shih, CY Takeda, H AF Liu, YZ Nyquist, LE Wiesmann, H Shih, CY Takeda, H TI The age of plagioclase-diopside inclusions in the Caddo county meteorite: Rb-Sr and Al-Mg isochrons. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract ID IAB IRON; CHONDRITES C1 Chiba Inst Tech, Res Inst, Narashino, Chiba 2750016, Japan. Lockheed Martin Space Mission Syst & Serv Co, Houston, TX 77058 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NR 9 TC 2 Z9 2 U1 0 U2 1 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 SU S BP A89 EP A89 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 581CZ UT WOS:000177274700160 ER PT J AU Lofgren, GE Le, L AF Lofgren, GE Le, L TI Experimental replication of relict "dusty" olivine in type 1B chondrules. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Lock Heed Martin, Houston, TX 77058 USA. NR 4 TC 2 Z9 2 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 SU S BP A90 EP A90 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 581CZ UT WOS:000177274700162 ER PT J AU Matrajt, G Joswiak, D Keller, L Brownlee, D AF Matrajt, G Joswiak, D Keller, L Brownlee, D TI Could ferrihydrite be a host phase of organics in IDPS? SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract ID TRANSFORMATION; CHONDRITE; MATRIX C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Univ Washington, Dept Astron, Seattle, WA 98195 USA. NR 9 TC 1 Z9 1 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 SU S BP A96 EP A96 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 581CZ UT WOS:000177274700174 ER PT J AU McCanta, MC Rutherford, MJ Musselwhite, DS AF McCanta, MC Rutherford, MJ Musselwhite, DS TI An experimental study of ree partitioning between a dry shergottite melt and pigeonite as a function of fO(2): Implications for the Martian interior. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract C1 NASA, SR, ARES Res Off, JSC, Houston, TX 77058 USA. Brown Univ, Dept Geol Sci, Providence, RI 02912 USA. NR 6 TC 3 Z9 3 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 SU S BP A97 EP A97 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 581CZ UT WOS:000177274700176 ER PT J AU Messenger, S Keller, LP AF Messenger, S Keller, LP TI Oxygen isotopic analyses of crystalline silicates and oxides in interplanetary dust. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Washington Univ, Space Sci Lab, St Louis, MO 63130 USA. Washington Univ, Dept Phys, St Louis, MO 63130 USA. NR 2 TC 1 Z9 1 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 SU S BP A99 EP A99 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 581CZ UT WOS:000177274700181 ER PT J AU Mikouchi, T Miyamoto, M Koizumi, E Monkawa, A McKay, G AF Mikouchi, T Miyamoto, M Koizumi, E Monkawa, A McKay, G TI Maskelynite recrystallization: Implications for shock and reheating histories of several achondrites. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract ID PLANETARY C1 NASA, Lyndon B Johnson Space Ctr, ST, Houston, TX 77058 USA. Univ Tokyo, Dept Earth & Planetary Sci, Tokyo 1130033, Japan. NR 7 TC 3 Z9 3 U1 0 U2 2 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 SU S BP A100 EP A100 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 581CZ UT WOS:000177274700182 ER PT J AU Mittlefehldt, DW Galindo, C AF Mittlefehldt, DW Galindo, C TI Petrology and geochemistry of unbrecci-ated, metamorphosed eucrites. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract C1 Hernandez Engn Inc, Houston, TX USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NR 2 TC 1 Z9 1 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 SU S BP A101 EP A101 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 581CZ UT WOS:000177274700184 ER PT J AU Mittlefehldt, DW AF Mittlefehldt, DW TI Geochemistry of new, unusual diogenites and constraints on diogenite genesis. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NR 2 TC 6 Z9 6 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 SU S BP A100 EP A100 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 581CZ UT WOS:000177274700183 ER PT J AU Musselwhite, DS Jones, JH AF Musselwhite, DS Jones, JH TI Variation in the augite/melt partitioning of SM, EU and GD with Fo(2): Implications for the oxidation state of the Martian mantle. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract ID CRUST; MARS C1 NASA, Lyndon B Johnson Space Ctr, ARES Res Off, SR, Houston, TX 77058 USA. NR 6 TC 3 Z9 3 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 SU S BP A106 EP A106 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 581CZ UT WOS:000177274700195 ER PT J AU Nakamura, K Zolensky, ME Tomita, S Tomeoka, K AF Nakamura, K Zolensky, ME Tomita, S Tomeoka, K TI Raman spectroscopy of carbonaceous globules in the Tagish Lake chondrite. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract C1 Kobe Univ, Dept Elect & Elect Engn, Kobe, Hyogo, Japan. NASA, JSC, Houston, TX USA. Kobe Univ, Dept Earth & Planetary Sci, Kobe, Hyogo, Japan. RI Tomita, Satoshi/A-4008-2011 OI Tomita, Satoshi/0000-0002-2514-9675 NR 6 TC 1 Z9 1 U1 2 U2 4 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 SU S BP A107 EP A107 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 581CZ UT WOS:000177274700197 ER PT J AU Nuth, JA Michael, BP AF Nuth, JA Michael, BP TI Experimental determination of the vapor-to-crystal condensation efficiency for zinc metal. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract C1 Catholic Univ Amer, Dept Chem, Washington, DC 20064 USA. NASA, Goddard Space Flight Ctr, Astrochem Branch, Greenbelt, MD 20771 USA. RI Michael, Patrick/N-6948-2013 OI Michael, Patrick/0000-0002-4742-4543 NR 2 TC 0 Z9 0 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 SU S BP A111 EP A111 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 581CZ UT WOS:000177274700205 ER PT J AU Nyquist, LE AF Nyquist, LE TI Short-lived radioactivities and planetary accretion and differentiation. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract ID EARLY SOLAR-SYSTEM; PLANETESIMALS; CHONDRITES; AL-26 C1 NASA, Lyndon B Johnson Space Ctr, Astromat SR, Houston, TX 77058 USA. NR 16 TC 0 Z9 0 U1 0 U2 2 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 SU S BP A112 EP A112 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 581CZ UT WOS:000177274700206 ER PT J AU Ostro, SJ Benner, LAM Nolan, MC Giorgini, JD Jurgens, RF Rose, R Yeomans, DK AF Ostro, SJ Benner, LAM Nolan, MC Giorgini, JD Jurgens, RF Rose, R Yeomans, DK TI Radar observations of Asteroid 25143 (1998 SF36). SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract C1 Arecibo Observ, Arecibo, PR 00612 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 SU S BP A113 EP A113 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 581CZ UT WOS:000177274700209 ER PT J AU Papanastassiou, DA Bogdanovski, O Wasserburg, GJ AF Papanastassiou, DA Bogdanovski, O Wasserburg, GJ TI Mn-53-Cr-53 systematics in allende refractory inclusions. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract C1 Jet Prop Lab, ESS Div, Pasadena, CA 91109 USA. CALTECH, GPS Div, Lunat Asylum, Pasadena, CA 91125 USA. NR 3 TC 4 Z9 4 U1 0 U2 2 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 SU S BP A114 EP A114 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 581CZ UT WOS:000177274700211 ER PT J AU Rao, MN McKay, DS AF Rao, MN McKay, DS TI Martian soil records in shergottite glass veins. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract ID METEORITE C1 Lockheed Martin, Houston, TX USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 SU S BP A121 EP A121 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 581CZ UT WOS:000177274700224 ER PT J AU Russell, CT Coradini, A Feldman, WC Jaumann, R Konopliv, AS McCord, TB McFadden, LA McSween, HY Mottola, S Neukum, G Pieters, CM Raymond, CA Smith, DE Sykes, MV Williams, BG Zuber, MT AF Russell, CT Coradini, A Feldman, WC Jaumann, R Konopliv, AS McCord, TB McFadden, LA McSween, HY Mottola, S Neukum, G Pieters, CM Raymond, CA Smith, DE Sykes, MV Williams, BG Zuber, MT TI Dawn discovery mission: A journey to the beginning of the solar system. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract C1 Univ Calif Los Angeles, Inst Geophys, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90095 USA. Ist Astrofis Spaziale, CNR, I-0133 Rome, Italy. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. DLR, German Aerosp Ctr, D-12489 Berlin, Germany. Jet Prop Lab, Pasadena, CA 91109 USA. Univ Hawaii, Honolulu, HI 96822 USA. Univ Maryland, College Pk, MD 20742 USA. Univ Tennessee, Knoxville, TN 37996 USA. Brown Univ, Providence, RI 02912 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Arizona, Tucson, AZ 85721 USA. MIT, Cambridge, MA 02139 USA. RI McFadden, Lucy-Ann/I-4902-2013 OI McFadden, Lucy-Ann/0000-0002-0537-9975 NR 0 TC 0 Z9 0 U1 0 U2 1 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 SU S BP A123 EP A123 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 581CZ UT WOS:000177274700229 ER PT J AU Sandford, SA Bernstein, MP Dworkin, JP Cooper, GW Allamandola, LJ AF Sandford, SA Bernstein, MP Dworkin, JP Cooper, GW Allamandola, LJ TI The production of amino acids in interstellar ices - Implications for meteoritic organics. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. SETI Inst, Ctr Study Life Universe, Mt View, CA 94043 USA. RI Dworkin, Jason/C-9417-2012 OI Dworkin, Jason/0000-0002-3961-8997 NR 7 TC 1 Z9 1 U1 0 U2 5 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 SU S BP A125 EP A125 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 581CZ UT WOS:000177274700233 ER PT J AU Sears, DWG Allen, CC Britt, D Brownlee, DE Pieters, CM Scheeres, D Scott, ERD AF Sears, DWG Allen, CC Britt, D Brownlee, DE Pieters, CM Scheeres, D Scott, ERD TI The Hera near-earth asteroid sample return mission: Science requirements of the sample collector. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract C1 Univ Arkansas, Arkansas Oklahoma Ctr Space & Planetary Sci, Fayetteville, AR 72701 USA. Lyndon B Johnson Space Ctr, Houston, TX USA. Univ Tennessee, Knoxville, TN 37996 USA. Univ Washington, Seattle, WA 98195 USA. Brown Univ, Providence, RI 02912 USA. Univ Michigan, Ann Arbor, MI 48109 USA. Univ Hawaii, Hawaii Inst Geophys & Planetol, Honolulu, HI 96822 USA. NR 5 TC 1 Z9 1 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 SU S BP A129 EP A129 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 581CZ UT WOS:000177274700240 ER PT J AU Sipiera, PP Schwade, JR Jerman, GA Hoover, RB AF Sipiera, PP Schwade, JR Jerman, GA Hoover, RB TI Classification of nineteen stone meteorites from the moulton escarpment in the Thiel mountains, Antarctica. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract C1 Harper Coll, Schmitt Meteorite Res Grp, Palatine, IL 60067 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 6 TC 3 Z9 3 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 SU S BP A132 EP A132 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 581CZ UT WOS:000177274700246 ER PT J AU Takeda, H Ishii, T Otsuki, M Liu, YZ Nyquist, LE AF Takeda, H Ishii, T Otsuki, M Liu, YZ Nyquist, LE TI Mineralogy of andesitic plagioclase-diopside material in the caddo county IAB iron. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract C1 Chiba Inst Technol, Inst Res, Narashino, Chiba 2750016, Japan. Univ Tokyo, Ocean Res Inst, Nakano Ku, Tokyo 1640014, Japan. NASA, Lyndon B Johnson Space Ctr, Astromat SR, Houston, TX 77058 USA. NR 4 TC 1 Z9 1 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 SU S BP A139 EP A139 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 581CZ UT WOS:000177274700260 ER PT J AU Whitehead, J Grieve, RAF Garvin, JB AF Whitehead, J Grieve, RAF Garvin, JB TI An evaluation of the scatter in mola depth vs diameter data for Martian complex craters using Viking and moc images. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract C1 Univ New Brunswick, Planetary & Space Sci Ctr, Fredericton, NB E3B 5A3, Canada. Natl Resources Canada, Ottawa, ON K1A 0E4, Canada. NASA Headquaters, Off Space Sci, Washington, DC 20546 USA. RI Whitby, James/J-4559-2012 OI Whitby, James/0000-0002-5716-6875 NR 2 TC 2 Z9 2 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 SU S BP A150 EP A150 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 581CZ UT WOS:000177274700282 ER PT J AU Zieg, MJ Lofgren, GE AF Zieg, MJ Lofgren, GE TI Evaluation and interpretation of chondrule simulation experiments using crystal size distributions. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 SU S BP A154 EP A154 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 581CZ UT WOS:000177274700290 ER PT J AU Zolensky, ME Tonui, EK Bevan, AWR Le, L Clayton, RN Mayeda, TK AF Zolensky, ME Tonui, EK Bevan, AWR Le, L Clayton, RN Mayeda, TK TI A new C-chondrite genomict breccia with metamorphosed clasts. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract ID CV3 CHONDRITES C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Western Australian Museum, Perth, WA 6000, Australia. Lockheed Martin, Houston, TX 77058 USA. Univ Chicago, Chicago, IL 60637 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 2002 VL 37 IS 7 SU S BP A155 EP A155 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 581CZ UT WOS:000177274700293 ER PT J AU Koopmans, LVE Garrett, MA Blandford, RD Lawrence, CR Patnaik, AR Porcas, RW AF Koopmans, LVE Garrett, MA Blandford, RD Lawrence, CR Patnaik, AR Porcas, RW TI 2016+112: a gravitationally lensed type II quasar SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE gravitational lensing; quasars : general; radio continuum : general ID SYSTEM 2016+112; DARK CLUSTER; RADIO OBSERVATIONS; MG 2016+112; GALAXIES; REDSHIFT; MODELS; IMAGE AB A single-screen model of the gravitational lens system 2016+112 is proposed, that explains recent Hubble Space Telescope (HST ) infrared (NICMOS-F160W) observations and new high-resolution European VLBI Network (EVN) 5-GHz radio observations, presented in this paper. In particular, we find that a massive 'dark' structure at the lens position, previously suggested by X-ray, optical and spectroscopic observations of the field around 2016+112, is not necessarily required to accommodate the strong-lensing constraints. A massive structure to the north-west of the lens system, suggested from a weak-lensing analysis of the field, is included in the model. The lensed source is an X-ray bright active galaxy at z = 3.273 with a central bright optical continuum core and strong narrow emission lines, suggestive of a type II quasar. The EVN 5-GHz radio maps show a radio jet structure with at least two compact subcomponents. We propose that the diamond caustic crosses the counter-jet of the radio source, so that part of the counter-jet, host galaxy and narrow-line emission regions are quadruply imaged. The remainder of the radio source, including the core, is doubly imaged. Our lens model predicts a very high magnification (musimilar to 300) at the brightness peaks of the inner two radio components of complex C. If the jet exhibits relativistic velocities on microarsecond scales, it might result in apparent hyperluminal motion. However, the lack of strong radio variability and the peaked radio spectrum imply that these motions need not be present in the source. Our model furthermore implies that the optical spectrum of C' can only show features of the active galactic nuclei and its host galaxy. C1 CALTECH, Pasadena, CA 91125 USA. Joint Inst VLBI Europe, NL-7990 AA Dwingeloo, Netherlands. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Max Planck Inst Radioastron, D-53121 Bonn, Germany. RP Koopmans, LVE (reprint author), CALTECH, Mailcode 130-33, Pasadena, CA 91125 USA. NR 36 TC 30 Z9 30 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 JUL PY 2002 VL 334 IS 1 BP 39 EP 47 DI 10.1046/j.1365-8711.2002.05438.x PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 573MT UT WOS:000176834400006 ER PT J AU Jonker, PG van der Klis, M Homan, J Mendez, M Lewin, WHG Wijnands, R Zhang, W AF Jonker, PG van der Klis, M Homan, J Mendez, M Lewin, WHG Wijnands, R Zhang, W TI Low- and high-frequency variability as a function of spectral properties in the bright X-ray binary GX 5-1 SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE accretion, accretion discs; stars : individual : GX 5-1; stars : neutron; X-rays : stars ID QUASI-PERIODIC OSCILLATIONS; BLACK-HOLE CANDIDATES; MULTIWAVELENGTH CAMPAIGN; GENERAL-RELATIVITY; NEUTRON-STAR; GX5-1; SCORPIUS-X-1; MECHANISMS; DISCOVERY; BEHAVIOR AB We report on a detailed analysis of data obtained over nearly four years with the Rossi X-ray Timing Explorer of the Z source GX 5-1. From a spectral analysis using a hardness-intensity diagram it was found that the source traced out the typical Z-shaped pattern. The study of the power spectral properties showed that when the source moved on the horizontal branch towards the normal branch the fractional rms amplitudes and time-scales of all variability decreased, while their FWHMs increased. The frequency separation of the two kHz QPO peaks decreased from 344+/-12 to 232+/-13 Hz, while the frequency of the lower and upper kHz QPO increased from 172+/-10 to 608+/-6 Hz and from 516+/-10 to 840+/-12 Hz, respectively. At low frequencies, besides the horizontal branch oscillation (HBO) and its second harmonic, two additional broad Lorentzian components were needed to obtain acceptable fits. These broad Lorentzians have Q -values of similar to1-2 and frequencies 0.5 and 1.5 times the HBO frequency. When interpreted as being related to the HBO, they seem to favour disc models for the HBO over the magnetic beat-frequency model. The frequency of the normal branch oscillations changed slightly and non-monotonically, while on the normal branch between similar to6 Hz at both ends and 5.25+/-0.05 Hz near the middle of the branch. It evolved into a flat-topped noise component on the flaring branch. We compared the timing properties of the some of the Z sources. We also compare the timing properties and colour-colour diagrams (CDs) of GX 5-1 with those of the back hole candidate XTE J1550-564 and the atoll source 4U 1608-52. The CDs are strikingly similar when a colour scheme commonly employed in back hole studies is used. However, this may be a degeneracy as the CDs turn out to be more complicated when colours common in neutron star studies are employed. Apart from some remarkable similarities between the CD of XTE J1550-564 and that of 4U 1608-52, several differences can be seen between these CDs and that of GX 5-1. Conclusions on spectral states or properties based solely on the use of CDs using the 'black hole scheme' should be regarded with caution. C1 Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. SRON, NL-3584 CA Utrecht, Netherlands. MIT, Dept Phys, Cambridge, MA 02138 USA. MIT, Ctr Space Res, Cambridge, MA 02139 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Jonker, PG (reprint author), Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England. RI Mendez, Mariano/C-8011-2012 OI Mendez, Mariano/0000-0003-2187-2708 NR 64 TC 43 Z9 43 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 JUL PY 2002 VL 333 IS 3 BP 665 EP 678 DI 10.1046/j.1365-8711.2002.05442.x PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 568EX UT WOS:000176530400018 ER PT J AU Casas-Miranda, R Mo, HJ Sheth, RK Boerner, G AF Casas-Miranda, R Mo, HJ Sheth, RK Boerner, G TI On the distribution of haloes, galaxies and mass SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE galaxies : clusters : general; galaxies : formation; cosmology : theory; dark matter ID HIGH-ORDER CORRELATIONS; DARK-MATTER HALOES; ANALYTIC MODEL; CLUSTERS; CONDENSATION; UNIVERSE; BIAS AB The stochasticity in the distribution of dark haloes in the cosmic density field is reflected in the distribution function P-V (N (h) \delta (m) ), which gives the probability of finding N (h) haloes in a volume V with mass density contrast delta (m) . We study the properties of this function using high-resolution N -body simulations, and find that P-V (N (h) \delta (m) ) is significantly non-Poisson. The ratio between the variance and the mean goes from similar to1 (Poisson) at 1+delta (m) <<1 to <1 (sub-Poisson) at 1+delta (m) similar to1< to >1 (super-Poisson) at 1+δ (m) >>1. The mean bias relation is found to be well described by halo bias models based on the Press-Schechter formalism. The sub-Poisson variance can be explained as a result of halo exclusion, while the super-Poisson variance at high delta (m) may be explained as a result of halo clustering. A simple phenomenological model is proposed to describe the behaviour of the variance as a function of delta (m) . Galaxy distribution in the cosmic density field predicted by semi-analytic models of galaxy formation shows similar stochastic behaviour. We discuss the implications of the stochasticity in halo bias to the modelling of higher order moments of dark haloes and of galaxies. C1 Max Planck Inst Astrophys, D-85741 Garching, Germany. NASA, Fermilab Astrophys Grp, Batavia, IL 60510 USA. RP Casas-Miranda, R (reprint author), Max Planck Inst Astrophys, Karl Schwarzschild Str 1, D-85741 Garching, Germany. RI Mo, Houjun/P-7811-2015 NR 30 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 JUL PY 2002 VL 333 IS 4 BP 730 EP 738 DI 10.1046/j.1365-8711.2002.05378.x PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 572AY UT WOS:000176752400002 ER PT J AU McCaul, EW Cohen, C AF McCaul, EW Cohen, C TI The impact on simulated storm structure and intensity of variations in the mixed layer and moist layer depths SO MONTHLY WEATHER REVIEW LA English DT Article ID SUPERCELL MORPHOLOGY; CONVECTIVE STORMS; CLOUDS; ENVIRONMENTS; ENTRAINMENT; EVOLUTION; BUOYANCY; SHEAR; PRECIPITATION; THUNDERSTORMS AB The sensitivities of convective storm structure and intensity to variations in the depths of the prestorm mixed layer, represented here by the environmental lifted condensation level (LCL), and moist layer, represented by the level of free convection (LFC), are studied using a three-dimensional cloud model containing ice physics. Matrices of simulations are generated for idealized environments featuring both small and large LCL = LFC altitudes, using a single moderately sheared curved hodograph trace in conjunction with convective available potential energy (CAPE) values of either 800 or 2000 J kg(-1), with the matrices consisting of all four combinations of two distinct choices of buoyancy and shear profile shape. For each value of CAPE, the LCL = LFC altitudes are also allowed to vary in a separate series of simulations based on the most highly compressed buoyancy and shear profiles used for that CAPE, with the environmental buoyancy profile shape, subcloud equivalent potential temperature, subcloud lapse rates of temperature and moisture, and wind profile held fixed. Two other special simulations, one for each CAPE, are conducted using the high LFC and the lowered LCL, with a neutrally buoyant environmental thermal profile specified in between, such that the equivalent potential temperature was similar to that at the LCL. These latter two cases correspond to situations where the moist layer depth exceeds that of the mixed layer, whereas in all the other cases the two depths were equal. Results show that for the CAPE-starved environments (CAPE = 800 J kg(-1)) the simulated storms are supercells that are generally largest and most intense when LCL = LFC altitudes lie in the approximate range 1.5-2.5 km above the surface. The simulations show similar trends for the shear-starved (CAPE = 2000 J kg(-1)) environments, except that a tendency toward outflow dominance and multicell morphology is more evident when the LCL = LFC is high. For choices of LCL = LFC height within the optimal 1.5-2.5-km range, peak storm updraft overturning efficiency may approach 100% relative to parcel theory, while for lower LCL = LFC heights, overturning efficiency is reduced significantly. The enhancements of overturning efficiency with increasing LFC height are shown to be associated with systematic increases in both updraft effective diameter and the mean equivalent potential temperature of the low-level updraft, which reaches a maximum near the LFC. For the shear-starved environments, the tendency for outflow dominance is eliminated, but a large overturning efficiency maintained, when a low LCL is used in conjunction with a high LFC. The result regarding outflow dominance at large LCL derives from enhanced evaporation of precipitation in the deeper and drier subcloud layer, but the beneficial effect of a high LFC on convective overturning efficiency, at first glance surprising, derives from the enhanced depth of the moist layer containing the maximum CAPE. The importance of the moist layer depth is highlighted in tests that show that high-LFC storms simulated in environments where the neutrally buoyant sub-LFC layer contains a layer of reduced equivalent potential temperature experience a corresponding decrease in updraft strength. The simulation findings presented here appear to be consistent with statistics from previous severe storm environment climatologies, but provide a new framework for interpreting those statistics. C1 NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, Huntsville, AL 35812 USA. RP McCaul, EW (reprint author), Inst Global Change Res & Educ, 4950 Corp Dr,Suite 200, Huntsville, AL 35806 USA. NR 33 TC 47 Z9 50 U1 1 U2 6 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD JUL PY 2002 VL 130 IS 7 BP 1722 EP 1748 DI 10.1175/1520-0493(2002)130<1722:TIOSSS>2.0.CO;2 PG 27 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 556NL UT WOS:000175855800003 ER PT J AU Weidenspointner, G Harris, MJ Jean, P Diallo, N AF Weidenspointner, G Harris, MJ Jean, P Diallo, N TI Instrumental lines of astrophysical relevance in TGRS and SPI SO NEW ASTRONOMY REVIEWS LA English DT Article; Proceedings Paper CT International Workshop of the Max-Planck-Gesellschaft CY MAY, 2001 CL RINGBERG CASTLE, GERMANY SP Max Planck Gesell DE data analysis; gamma-ray lines ID BORNE GE SPECTROMETERS; BALLOON AB High resolution gamma-ray spectroscopy at energies around 1 MeV, as with SPI on board INTEGRAL, is a powerful tool for astronomy with radioactivities. We do not expect the SPI signal-to-background ratio for any of the anticipated gamma-ray sources to exceed a few percent; hence detailed modelling of the instrumental background will be crucial. We exploit the similarities between TGRS on board WIND and SPI with respect to orbit and radiation environment, as well as detector design and material composition, to anticipate the most important instrumental background lines and their production channels in SPI at the energies of selected gamma-ray lines of astrophysical relevance. (C) 2002 Elsevier Science B.V. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. USRA, Seabrook, MD 20706 USA. Ctr Etud Spatiale Rayonnements, F-31028 Toulouse, France. Univ Southampton, Southampton SO17 1BJ, Hants, England. RP Weidenspointner, G (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. EM ggw@tgrosf.gsfc.nasa.gov NR 12 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 1387-6473 J9 NEW ASTRON REV JI New Astron. Rev. PD JUL PY 2002 VL 46 IS 8-10 BP 625 EP 629 AR PII S1387-6473(02)00211-7 DI 10.1016/S1387-6473(02)00211-7 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 582VT UT WOS:000177372400030 ER PT J AU Diethelm, K Ford, NJ Freed, AD AF Diethelm, K Ford, NJ Freed, AD TI A predictor-corrector approach for the numerical solution of fractional differential equations SO NONLINEAR DYNAMICS LA English DT Article DE fractional differential equation; Caputo derivative; numerical solution; predictor-corrector method; Adams method ID INTEGRAL-EQUATIONS; 2ND KIND; CALCULUS; VOLTERRA AB We discuss an Adams-type predictor-corrector method for the numerical solution of fractional differential equations. The method may be used both for linear and for nonlinear problems, and it may be extended to multi-term equations (involving more than one differential operator) too. C1 Tech Univ Carolo Wilhelmina Braunschweig, Inst Angew Math, D-38106 Braunschweig, Germany. Chester Coll Higher Educ, Dept Math, Chester CH1 4BJ, Cheshire, England. NASA, John H Glenn Res Ctr Lewis Field, Polymers Branch, Cleveland, OH 44135 USA. RP Diethelm, K (reprint author), Tech Univ Carolo Wilhelmina Braunschweig, Inst Angew Math, Pockelsstr 14, D-38106 Braunschweig, Germany. OI Freed, Alan/0000-0002-3492-0628 NR 36 TC 670 Z9 702 U1 3 U2 63 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0924-090X J9 NONLINEAR DYNAM JI Nonlinear Dyn. PD JUL-SEP PY 2002 VL 29 IS 1-4 BP 3 EP 22 DI 10.1023/A:1016592219341 PG 20 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA 578VV UT WOS:000177142500002 ER PT J AU Lorenzo, CF Hartley, TT AF Lorenzo, CF Hartley, TT TI Variable order and distributed order fractional operators SO NONLINEAR DYNAMICS LA English DT Article DE variable order fractional operator; distributed order fractional operator; order distribution; Laplace transform; tailored fractional order operator; memory measure AB Many physical processes appear to exhibit fractional order behavior that may vary with time or space. The continuum of order in the fractional calculus allows the order of the fractional operator to be considered as a variable. This paper develops the concept of variable and distributed order fractional operators. Definitions based on the Riemann-Liouville definition are introduced and the behavior of the new operators is studied. Several time domain definitions that assign different arguments to the order q in the Riemann-Liouville definition are introduced. For each of these definitions various characteristics are determined. These include: time invariance of the operator, operator initialization, physical realization, linearity, operational transforms, and memory characteristics of the defining kernels. A measure (m(2)) for memory retentiveness of the order history is introduced. A generalized linear argument for the order q allows the concept of `tailored' variable order fractional operators whose m(2) memory may be chosen for a particular application. Memory retentiveness (m(2)) and order dynamic behavior are investigated and applications are shown. The concept of distributed order operators where the order of the time based operator depends on an additional independent (spatial) variable is also forwarded. Several definitions and their Laplace transforms are developed, analysis methods with these operators are demonstrated, and examples shown. Finally operators of multivariable and distributed order are defined and their various applications are outlined. C1 NASA, John H Glenn Res Ctr, Cleveland, OH 44135 USA. Univ Akron, Dept Elect Engn, Akron, OH 44325 USA. RP Lorenzo, CF (reprint author), NASA, John H Glenn Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 16 TC 177 Z9 184 U1 3 U2 17 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0924-090X J9 NONLINEAR DYNAM JI Nonlinear Dyn. PD JUL-SEP PY 2002 VL 29 IS 1-4 BP 57 EP 98 DI 10.1023/A:1016586905654 PG 42 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA 578VV UT WOS:000177142500005 ER PT J AU Hartley, TT Lorenzo, CF AF Hartley, TT Lorenzo, CF TI Dynamics and control of initialized fractional-order systems SO NONLINEAR DYNAMICS LA English DT Article DE fractional-order systems; control systems; order-distributions; fractional calculus ID VISCOELASTICITY; REPRESENTATION; OPERATORS; CALCULUS AB Due to the importance of historical effects in fractional-order systems, this paper presents a general fractional-order system and control theory that includes the time-varying initialization response. Previous studies have not properly accounted for these historical effects. The initialization response, along with the forced response, for fractional-order systems is determined. The scalar fractional-order impulse response is determined, and is a generalization of the exponential function. Stability properties of fractional-order systems are presented in the complex w-plane, which is a transformation of the s-plane. Time responses are discussed with respect to pole positions in the complex w-plane and frequency response behavior is included. A fractional-order vector space representation, which is a generalization of the state space concept, is presented including the initialization response. Control methods for vector representations of initialized fractional-order systems are shown. Finally, the fractional-order differintegral is generalized to continuous order-distributions which have the possibility of including all fractional orders in a transfer function. C1 Univ Akron, Dept Elect Engn, Akron, OH 44325 USA. NASA, John H Glenn Res Ctr, Cleveland, OH 44135 USA. RP Hartley, TT (reprint author), Univ Akron, Dept Elect Engn, Akron, OH 44325 USA. NR 43 TC 130 Z9 133 U1 1 U2 13 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0924-090X J9 NONLINEAR DYNAM JI Nonlinear Dyn. PD JUL-SEP PY 2002 VL 29 IS 1-4 BP 201 EP 233 DI 10.1023/A:1016534921583 PG 33 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA 578VV UT WOS:000177142500012 ER PT J AU de Bernardis, P Ade, PAR Bock, JJ Bond, JR Borrill, J Boscaleri, A Coble, K Contaldi, CR Crill, BP De Gasperis, G De Troia, G Farese, P Ganga, K Giacometti, M Hivon, E Hristov, VV Iacoangeli, A Jaffe, AH Jones, WC Lange, AE Martinis, L Mason, P Mauskopf, PD Melchiorri, A Montroy, T Natoli, P Netterfield, CB Pascale, E Piacentini, F Pogosyan, D Polenta, G Pongetti, F Prunet, S Romeo, G Ruhl, JE Scaramuzzi, F Vittorio, N AF de Bernardis, P Ade, PAR Bock, JJ Bond, JR Borrill, J Boscaleri, A Coble, K Contaldi, CR Crill, BP De Gasperis, G De Troia, G Farese, P Ganga, K Giacometti, M Hivon, E Hristov, VV Iacoangeli, A Jaffe, AH Jones, WC Lange, AE Martinis, L Mason, P Mauskopf, PD Melchiorri, A Montroy, T Natoli, P Netterfield, CB Pascale, E Piacentini, F Pogosyan, D Polenta, G Pongetti, F Prunet, S Romeo, G Ruhl, JE Scaramuzzi, F Vittorio, N TI The new images of the microwave sky: a concordance cosmology? SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 7th International Workshop on Topics in Astroparticle and Underground Physics CY SEP 08-12, 2001 CL LAB NAZL GRAN SASSO, ASSERGI, ITALY HO LAB NAZL GRAN SASSO ID GALACTIC DUST EMISSION; BACKGROUND-RADIATION; BOOMERANG; UNIVERSE; MAXIMA-1; MAPS; SUPERNOVAE; FIRAS; OMEGA AB The existence and anisotropy of the cosmic microwave background (CMB), the large scale distribution of Galaxies, the expansion of the Universe and the abundance of light elements can be all be explained with a single cosmological model. In this paper we focus on the CMB anisotropy maps produced by the BOOMERanG experiment and on their impact on cosmology. The images axe consistent with the result of acoustic oscillations of the photons-matter plasma in the pre-recombination Universe (z greater than or similar to 1000). We show how the instrument and the observations have been optimized and how the basic parameters of the model are derived from the data. These observations of the CMB are gaussian and point to a low curvature Universe (Omega similar to 1), as expected in the inflation scenario. In order to fit these observations and other cosmological evidence, the composition of the Universe must have significant contributions from dark matter (Omega(m) similar to 0.3) and dark energy (Omega(Lambda) similar to 0.7). C1 Univ Roma La Sapienza, Dipartimento Fis, I-00185 Rome, Italy. Dept Phys & Astron, Cardiff, S Glam, Wales. CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. Univ Toronto, CITA, Toronto, ON, Canada. LBNL, NERSC, Berkeley, CA USA. CNR, IROE, I-50127 Florence, Italy. Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. Univ Roma Tor Vergata, Dipartimento Fis, I-00173 Rome, Italy. CALTECH, IPAC, Pasadena, CA USA. Univ London Imperial Coll Sci Technol & Med, London SW7 2AZ, England. ENEA, Frascati, Italy. Dept Astron, Oxford, England. Univ Toronto, Dept Phys, Toronto, ON M5S 1A7, Canada. Ist Nazl Geofis, I-00161 Rome, Italy. RP Univ Roma La Sapienza, Dipartimento Fis, I-00185 Rome, Italy. RI Jaffe, Andrew/D-3526-2009; de Gasperis, Giancarlo/C-8534-2012; Piacentini, Francesco/E-7234-2010; OI de Gasperis, Giancarlo/0000-0003-2899-2171; Piacentini, Francesco/0000-0002-5444-9327; de Bernardis, Paolo/0000-0001-6547-6446; ROMEO, Giovanni/0000-0002-5535-7803; Polenta, Gianluca/0000-0003-4067-9196; Hivon, Eric/0000-0003-1880-2733 NR 48 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 EI 1873-3832 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD JUL PY 2002 VL 110 BP 128 EP 136 AR PII S0920-5632(02)01469-X PG 9 WC Physics, Particles & Fields SC Physics GA 570MG UT WOS:000176661600028 ER PT J AU Vitale, S Bender, P Brillet, A Buchman, S Cavalleri, A Cerdonio, M Cruise, M Cutler, C Danzmann, K Dolesi, R Folkner, W Gianolio, A Jafry, Y Hasinger, G Heinzel, G Hogan, C Hueller, M Hough, J Phinney, S Prince, T Richstone, D Robertson, D Rodrigues, M Rudiger, A Sandford, M Schilling, R Shoemaker, D Schutz, B Stebbins, R Stubbs, C Sumner, T Thorne, K Tinto, M Touboul, P Ward, H Weber, W Winkler, W AF Vitale, S Bender, P Brillet, A Buchman, S Cavalleri, A Cerdonio, M Cruise, M Cutler, C Danzmann, K Dolesi, R Folkner, W Gianolio, A Jafry, Y Hasinger, G Heinzel, G Hogan, C Hueller, M Hough, J Phinney, S Prince, T Richstone, D Robertson, D Rodrigues, M Rudiger, A Sandford, M Schilling, R Shoemaker, D Schutz, B Stebbins, R Stubbs, C Sumner, T Thorne, K Tinto, M Touboul, P Ward, H Weber, W Winkler, W TI LISA and its in-flight test precursor SMART-2 SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 7th International Workshop on Topics in Astroparticle and Underground Physics CY SEP 08-12, 2001 CL LAB NAZL GRAN SASSO, ASSERGI, ITALY HO LAB NAZL GRAN SASSO ID MISSION; SENSOR AB LISA will be the first space-borne gravitational wave observatory. It aims to detect gravitational waves in the 0.1 MHz + 1 Hz range from sources including galactic binaries, super-massive black-hole binaries, capture of objects by super-massive black-holes and stochastic background. LISA is an ESA approved Cornerstone Mission foreseen as a joint ESA-NASA endeavour to be launched in 2010-11. The principle of operation of LISA is based on laser ranging of test-masses under pure geodesic motion. Achieving pure geodesic motion at the level requested for LISA, 3 x 10(-15)ms(-2)/rootHz at 0.1 mHz, is considered a challenging technological objective. To reduce the risk, both ESA and NASA are pursuing an in-flight test of the relevant technology. The goal of the test is to demonstrate geodetic motion within one order of magnitude from the LISA performance. ESA has given this test as the primary goal of its technology dedicated mission SMART-2 with a launch in 2006. This paper describes the basics of LISA, its key technologies, and its in-flight precursor test on SMART-2. C1 Univ Trent, Dipartimento Fis, I-38050 Trento, Italy. Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Observ Cote Azur, F-06003 Nice, France. Stanford Univ, WW Hansen Expt Phys Labs, Stanford, CA 94305 USA. Univ Padua, Dipartimento Fis, I-35100 Padua, Italy. Univ Birmingham, Dept Phys & Astron, Birmingham B15 2TT, W Midlands, England. Max Planck Int Gravitat Phys, Albert Einstein Inst, Golm, Germany. Leibniz Univ Hannover, D-30167 Hannover, Germany. CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. ESA, Estec, Noordwijk, Netherlands. Max Planck Inst Extraterr Phys, D-37075 Garching, Germany. Univ Washington, Dept Phys, Seattle, WA 98195 USA. Univ Washington, Dept Astron, Seattle, WA 98195 USA. Univ Glasgow, Dept Phys & Astron, Glasgow G12 8QQ, Lanark, Scotland. Univ Michigan, Dept Astron, Ann Arbor, MI 48109 USA. Off Natl Etud & Rech Aerosp, Chatillon, France. Max Planck Inst Quantum Opt, Garching, Germany. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. MIT, Cambridge, MA 02139 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ London Imperial Coll Sci Technol & Med, Blackett Lab, London SW7 2BZ, England. RP Univ Trent, Dipartimento Fis, I-38050 Trento, Italy. RI Schutz, Bernard/B-1504-2010; Stubbs, Christopher/C-2829-2012; Weber, William/H-4351-2012; Stebbins, Robin/G-5009-2013; cavalleri, antonella/D-3678-2015; Vitale, Stefano/C-2312-2012 OI Stubbs, Christopher/0000-0003-0347-1724; Weber, William/0000-0003-1536-2410; cavalleri, antonella/0000-0003-0461-0968; Vitale, Stefano/0000-0002-2427-8918 NR 11 TC 54 Z9 54 U1 0 U2 6 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 JUL PY 2002 VL 110 BP 209 EP 216 AR PII S0920-5632(02)01484-6 PG 8 WC Physics, Particles & Fields SC Physics GA 570MG UT WOS:000176661600043 ER PT J AU Blasi, P Dick, R Kolb, EW AF Blasi, P Dick, R Kolb, EW TI Ultra-high energy cosmic rays: The annihilation of super-heavy relics SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 7th International Workshop on Topic in Astroparticle and Underground Physics CY SEP 08-12, 2001 CL LAB NAZL GRAN SASSO, ASSERGI, ITALY HO LAB NAZL GRAN SASSO ID DARK-MATTER; PARTICLES AB We investigate the possibility that ultra-high energy cosmic rays (UHECRs) originate from the annihilation of relic superheavy (SH) dark matter in the Galactic halo. In order to fit the data on UHECRs, a cross section of (sigma(A)v) similar to 10(-26)cm(2)(M-X/10(12) GeV)(3/2) is required if the SH dark matter follows a Navarro-Frenk-White (NFW) density profile. This would require extremely large-l contributions to the annihilation cross section. An interesting finding of our calculation is that the annihilation in sub-galactic clumps of-dark matter dominates over the annihilations in the smooth dark matter halo, thus implying much smaller values of the cross section needed to explain the observed fluxes of UHECRs. C1 Osserv Astrofis Arcetri, I-50125 Florence, Italy. Univ Saskatchewan, Dept Phys & Engn Phys, Saskatoon, SK S7N 5E2, Canada. Fermilab Natl Accelerator Lab, NASA, Fermilab Astrophys Ctr, Batavia, IL 60510 USA. Univ Chicago, Ctr Astron & Astrophys, Enrico Fermi Inst, Chicago, IL 60637 USA. RP Blasi, P (reprint author), Osserv Astrofis Arcetri, Largo E Fermi 5, I-50125 Florence, Italy. RI Dick, Rainer/H-5182-2011; Blasi, Pasquale/O-9345-2015 OI Blasi, Pasquale/0000-0003-2480-599X NR 15 TC 3 Z9 3 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD JUL PY 2002 VL 110 BP 494 EP 496 AR PII S0920-5632(02)01545-1 PG 3 WC Physics, Particles & Fields SC Physics GA 570MG UT WOS:000176661600105 ER PT J AU MacGibbon, JH Wichoski, UF AF MacGibbon, JH Wichoski, UF TI High energy tau neutrinos SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 7th International Workshop on Topic in Astroparticle and Underground Physics CY SEP 08-12, 2001 CL LAB NAZL GRAN SASSO, ASSERGI, ITALY HO LAB NAZL GRAN SASSO ID PRIMORDIAL BLACK-HOLES; COSMIC-RAYS AB The intrinsic tau neutrino flux from cosmological and astrophysical sources has usually been considered negligible in comparison to the electron and muon neutrino fluxes. However, the inclusion of the tau neutrino component coming from hadronic decay at the source can significantly modify the tau neutrino spectrum expected at Earth. We report our results on the high energy tau neutrino production and its implications for the observation of high energy neutrino events. C1 NASA, Johnson Space Ctr, Houston, TX 77058 USA. CENTRA IST, Dept Fis, P-1049001 Lisbon, Portugal. RP MacGibbon, JH (reprint author), NASA, Johnson Space Ctr, Code SN3, Houston, TX 77058 USA. NR 15 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD JUL PY 2002 VL 110 BP 528 EP 530 AR PII S0920-5632(02)01556-6 PG 3 WC Physics, Particles & Fields SC Physics GA 570MG UT WOS:000176661600116 ER PT J AU Wilson, GS Barron, JA Ashworth, AC Askin, RA Carter, JA Curren, MG Dalhuisen, DH Friedmann, EI Fyodorov-Davidov, DG Gilichinsky, DA Harper, MA Harwood, DM Hiemstra, JF Janecek, TR Licht, KJ Ostroumov, VE Powell, RD Rivkina, EM Rose, SA Stroeven, AP Stroeven, P van der Meer, JJM Wizevich, MC AF Wilson, GS Barron, JA Ashworth, AC Askin, RA Carter, JA Curren, MG Dalhuisen, DH Friedmann, EI Fyodorov-Davidov, DG Gilichinsky, DA Harper, MA Harwood, DM Hiemstra, JF Janecek, TR Licht, KJ Ostroumov, VE Powell, RD Rivkina, EM Rose, SA Stroeven, AP Stroeven, P van der Meer, JJM Wizevich, MC TI The Mount Feather Diamicton of the Sirius Group: an accumulation of indicators of Neogene Antarctic glacial and climatic history SO PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY LA English DT Article; Proceedings Paper CT Symposium on Palaeoclimate Reconstructions Using Fossils CY APR, 2000 CL UNIV MANCHESTER, MANCHESTER, ENGLAND SP Palaeontol Assoc, Geol Soc London HO UNIV MANCHESTER DE Antarctica; ice sheet; Sirius Group; climate; coring; microfossils ID SOUTHERN VICTORIA-LAND; ICE-SHEET; DRY-VALLEYS; TRANSANTARCTIC MOUNTAINS; MARINE; SEDIMENTATION; PALEOCLIMATE; REDUCTION; DEPOSITS; DIATOMS AB A paucity of data from the Antarctic continent has resulted in conflicting interpretations of Neogene Antarctic glacial history. Much of the debate centres on interpretations of the glacigene Sirius Group strata that crop out as discrete deposits along the length of the Transantarctic Mountains and in particular on its age and the origin of the siliceous microfossils it encloses. Pliocene marine diatoms enclosed within Sirius Group strata are inferred to indicate a dynamic East Antarctic ice sheet that was much reduced, compared with today, in the early-middle Pliocene and then expanded again in the late Pliocene. However, the geomorphology of the Dry Valleys region is interpreted to represent a relatively long-lived (middle Miocene-recent) and stable polar climatic regime similar to that of today. The Mount Feather Diamicton infills a palaeovalley at ca. 2500 m on the NE flank of Mount Feather in the Dry Valleys region and has been included within the Sirius Group. We obtained four shallow cores (COMRAC 8, 9, 10 and 11) from beneath the permafrost boundary in the Mount Feather Diamicton in order to understand its origin and relationship with the surrounding landscape. Detailed studies of these cores (stratigraphy, sedimentology, palaeontology, micromorphology, petrography and fabric) have yielded new data that demonstrate a much more complex climatic and glacial history for the Mount Feather Diamicton than in previous interpretations. The data indicate that the Mount Feather Diamicton was deposited beneath a wet based glacier fed from a larger ice sheet behind the Transantarctic Mountains. It is, however, unlikely that this ice sheet overtopped Mount Feather (2985 m). A near-in situ non-marine diatom assemblage was recovered from 90 cm depth in COMRAC 10 and indicates a maximum depositional age of Late Miocene for the Mount Feather Diamicton. A Subsequent glacial episode has distributed a boulder blanket across the surface of the diamicton. Other post-depositional processes include drying, infilling of surface layers with aeolian sediment, and the development of melt-water runnels. We interpret these combined data to indicate the persistence of more temperate climatic and glacial conditions in the vicinity of Mount Feather until at least the Late Miocene. (C) 2002 Elsevier Science B.V. All rights reserved. C1 Univ Oxford, Dept Earth Sci, Oxford OX1 3PR, England. US Geol Survey, Menlo Pk, CA 94025 USA. N Dakota State Univ, Dept Geosci, Fargo, ND 58105 USA. Ohio State Univ, Byrd Polar Res Ctr, Columbus, OH 43210 USA. Victoria Univ Wellington, Sch Earth Sci, Wellington, New Zealand. Florida State Univ, Dept Geol, Antarctic Marine Geol Res Facil, Tallahassee, FL 32306 USA. Delft Univ Technol, Fac Civil Engn, NL-2628 CN Delft, Netherlands. NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. Russian Acad Sci, Inst Soil Sci & Cryol, Pushchino 142292, Moscow Region, Russia. Univ Nebraska, Dept Geosci, Lincoln, NE 68588 USA. Univ Glasgow, Dept Geog & Topog Sci, Glasgow G12 8QQ, Lanark, Scotland. Indiana Univ Purdue Univ, Dept Geol, Indianapolis, IN 46202 USA. No Illinois Univ, Dept Geol & Environm Geosci, De Kalb, IL 60115 USA. Stockholm Univ, Dept Quaternary Res, S-10691 Stockholm, Sweden. Univ London Queen Mary & Westfield Coll, Dept Geog, London E1 4NS, England. Cornell Univ, Dept Geol Sci, Ithaca, NY 14853 USA. RP Wilson, GS (reprint author), Univ Otago, Dept Geol, POB 56, Dunedin, New Zealand. RI Wilson, Gary/B-3803-2010; Hiemstra, John/E-4192-2013; Stroeven, Arjen/I-7330-2013; OI Stroeven, Arjen/0000-0001-8812-2253; Rivkina, Elizaveta/0000-0001-7949-8056 NR 63 TC 30 Z9 31 U1 1 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0031-0182 J9 PALAEOGEOGR PALAEOCL JI Paleogeogr. Paleoclimatol. Paleoecol. PD JUL 1 PY 2002 VL 182 IS 1-2 SI SI BP 117 EP 131 AR PII S0031-0182(01)00455-2 DI 10.1016/S0031-0182(01)00455-2 PG 15 WC Geography, Physical; Geosciences, Multidisciplinary; Paleontology SC Physical Geography; Geology; Paleontology GA 569PN UT WOS:000176611200008 ER PT J AU Javan, A Kocharovskaya, O Lee, H Scully, MO AF Javan, A Kocharovskaya, O Lee, H Scully, MO TI Narrowing of electromagnetically induced transparency resonance in a Doppler-broadened medium SO PHYSICAL REVIEW A LA English DT Article ID GROUP-VELOCITY; DISPERSIVE PROPERTIES; RUBIDIUM ATOMS; GAS; INVERSION; SPECTROSCOPY; REDUCTION; COHERENCE; LIGHT AB We derive an analytic expression for the linewidth of electromagnetically induced transparency (EIT) resonance in a Doppler-broadened system. It is shown here that for relatively low intensity of the driving field the EIT linewidth is proportional to the square root of intensity and is independent of the Doppler width, similar to the laser-induced line narrowing effect described by Feld and Javan. In the limit of high intensity we recover the usual power-broadening case where the EIT linewidth is proportional to the intensity and inversely proportional to the Doppler width. C1 MIT, Dept Phys, Cambridge, MA 02139 USA. Max Planck Inst Quantum Opt, D-85748 Garching, Germany. Russian Acad Sci, Inst Appl Phys, Nizhnii Novgorod 603120, Russia. Texas A&M Univ, Dept Phys, College Stn, TX 77843 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Javan, A (reprint author), MIT, Dept Phys, Cambridge, MA 02139 USA. NR 32 TC 128 Z9 130 U1 1 U2 7 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD JUL PY 2002 VL 66 IS 1 AR 013805 DI 10.1103/PhysRevA.66.013805 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 579WH UT WOS:000177200800115 ER PT J AU Abazajian, KN Beacom, JF Bell, NF AF Abazajian, KN Beacom, JF Bell, NF TI Stringent constraints on cosmological neutrino-antineutrino asymmetries from synchronized flavor transformation SO PHYSICAL REVIEW D LA English DT Article ID BIG-BANG NUCLEOSYNTHESIS; OSCILLATING NEUTRINOS; FINITE-TEMPERATURE; STERILE NEUTRINOS; LEPTON ASYMMETRY; UNIVERSE; GASES; B-8; ERA AB We assess a mechanism which can transform neutrino-antineutrino asymmetries between flavors in the early universe, and confirm that such transformation is unavoidable in the near bimaximal framework emerging for the neutrino mixing matrix. We show that the process is a standard Mikheyev-Smirnov-Wolfenstein flavor transformation dictated by a synchronization of momentum states. We also show that flavor "equilibration" is a special feature of maximal mixing, and carefully examine new constraints placed on neutrino asymmetries. In particular, the big bang nucleosynthesis limit on electron neutrino degeneracy \xi(e)\less than or similar to0.04 does not apply directly to all flavors, yet confirmation of the large-mixing-angle solution to the solar neutrino problem will eliminate the possibility of degenerate big bang nucleosynthesis. C1 Fermilab Natl Accelerator Lab, NASA, Fermilab Astrophys Ctr, Batavia, IL 60510 USA. RP Fermilab Natl Accelerator Lab, NASA, Fermilab Astrophys Ctr, POB 500, Batavia, IL 60510 USA. EM aba@fnal.gov; beacom@fnal.gov; nfb@fnal.gov OI Beacom, John/0000-0002-0005-2631 NR 60 TC 145 Z9 145 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0010 EI 2470-0029 J9 PHYS REV D JI Phys. Rev. D PD JUL 1 PY 2002 VL 66 IS 1 AR 013008 DI 10.1103/PhysRevD.66.013008 PN 2 PG 11 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 582FG UT WOS:000177338600017 ER PT J AU Sharp, MK Beacom, JF Formaggio, JA AF Sharp, MK Beacom, JF Formaggio, JA TI Potential for supernova neutrino detection in MiniBooNE SO PHYSICAL REVIEW D LA English DT Article ID CORE-COLLAPSE; POSTBOUNCE EVOLUTION; ANGULAR-DISTRIBUTION; NU(TAU) NEUTRINOS; MASS SIGNATURE; NUCLEOSYNTHESIS; BURST; TRANSFORMATION; OSCILLATIONS; SIMULATION AB The MiniBooNE detector at Fermilab is designed to search for nu(mu)-->nu(e) oscillation appearance at E(nu)similar to1 GeV and to make a decisive test of the LSND signal. The main detector (inside a veto shield) is a spherical volume containing 0.680 ktons of mineral oil. This inner volume, viewed by 1280 phototubes, is primarily a Cerenkov medium, as the scintillation yield is low. The entire detector is under a 3 m earth overburden. Though the detector is not optimized for low-energy (tens of MeV) events, and the cosmic-ray muon rate is high (10 kHz), we show that MiniBooNE can function as a useful supernova neutrino detector. Simple trigger-level cuts can greatly reduce the backgrounds due to cosmic-ray muons. For a canonical Galactic supernova at 10 kpc, about 190 supernova (ν) over bar (e)+p-->e(+)+n events would be detected. By adding MiniBooNE to the international network of supernova detectors, the possibility of a supernova being missed would be reduced. Additionally, the paths of the supernova neutrinos through Earth will be different for MiniBooNE and other detectors, thus allowing tests of matter-affected mixing effects on the neutrino signal. C1 Columbia Univ, Dept Phys, New York, NY 10027 USA. Fermilab Natl Accelerator Lab, NASA, Fermilab Astrophys Ctr, Batavia, IL 60510 USA. RP Sharp, MK (reprint author), Columbia Univ, Dept Phys, 538 W 120th St, New York, NY 10027 USA. EM msharp@phys.columbia.edu; beacom@fnal.gov; josephf@u.washington.edu OI Beacom, John/0000-0002-0005-2631 NR 50 TC 21 Z9 21 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD JUL 1 PY 2002 VL 66 IS 1 AR 013012 DI 10.1103/PhysRevD.66.013012 PG 7 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 582FG UT WOS:000177338600021 ER PT J AU Jaffe, C Ross, SD Lo, MW Marsden, J Farrelly, D Uzer, T AF Jaffe, C Ross, SD Lo, MW Marsden, J Farrelly, D Uzer, T TI Statistical theory of asteroid escape rates SO PHYSICAL REVIEW LETTERS LA English DT Article ID TRANSITION-STATE; HYDROGEN-ATOM; SOLAR-SYSTEM; DYNAMICS; IONIZATION; ORBITS; FIELDS; SPACE; MARS AB Transition states in phase space are identified and shown to regulate the rate of escape of asteroids temporarily captured in circumplanetary orbits. The transition states, similar to those occurring in chemical reaction dynamics, are then used to develop a statistical semianalytical theory for the rate of escape of asteroids temporarily captured by Mars. Theory and numerical simulations are found to agree to better than 1% . These calculations suggest that further development of transition state theory in celestial mechanics, as an alternative to large-scale numerical simulations, will be a fruitful approach to mass transport calculations. C1 CALTECH, Control & Dynam Syst Div 107 81, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. W Virginia Univ, Dept Chem, Morgantown, WV 26506 USA. Utah State Univ, Dept Chem, Logan, UT 84322 USA. Georgia Inst Technol, Ctr Nonlinear Sci, Atlanta, GA 30332 USA. Georgia Inst Technol, Sch Phys, Atlanta, GA 30332 USA. RP Jaffe, C (reprint author), CALTECH, Control & Dynam Syst Div 107 81, Pasadena, CA 91125 USA. RI Ross, Shane/B-7237-2009 OI Ross, Shane/0000-0001-5523-2376 NR 21 TC 82 Z9 83 U1 0 U2 5 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 JUL 1 PY 2002 VL 89 IS 1 AR 011101 DI 10.1103/PhysRevLett.89.011101 PG 4 WC Physics, Multidisciplinary SC Physics GA 563YN UT WOS:000176285700002 PM 12097024 ER PT J AU Wang, M Moin, P AF Wang, M Moin, P TI Dynamic wall modeling for large-eddy simulation of complex turbulent flows SO PHYSICS OF FLUIDS LA English DT Article ID APPROXIMATE BOUNDARY-CONDITIONS AB The efficacy of large-eddy simulation (LES) with wall modeling for complex turbulent flows is assessed by considering turbulent boundary-layer flows past an asymmetric trailing-edge. Wall models based on turbulent boundary-layer equations and their simpler variants are employed to compute the instantaneous wall shear stress, which is used as approximate boundary conditions for the LES. It is demonstrated that, as first noted by Cabot and Moin [Flow Turb. Combust. 63, 269 (2000)], when a Reynolds-averaged Navier-Stokes type eddy viscosity is used in the wall-layer equations with nonlinear convective terms, its value must be reduced to account for only the unresolved part of the Reynolds stress. A dynamically adjusted mixing-length eddy viscosity is used in the turbulent boundary-layer equation model, which is shown to be considerably more accurate than the simpler wall models based on the instantaneous log law. This method predicts low-order velocity statistics in good agreement with those from the full LES with resolved wall-layers, at a small fraction of the original computational cost. In particular, the unsteady separation near the trailing-edge is captured correctly, and the prediction of surface pressure fluctuations also shows promise. (C) 2002 American Institute of Physics. C1 Stanford Univ, NASA, Ames Res Ctr, Ctr Turbulence Res, Moffett Field, CA 94035 USA. RP Wang, M (reprint author), Stanford Univ, NASA, Ames Res Ctr, Ctr Turbulence Res, MS 19-44, Moffett Field, CA 94035 USA. RI Wang, Meng/C-1622-2012 NR 14 TC 119 Z9 120 U1 1 U2 17 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD JUL PY 2002 VL 14 IS 7 BP 2043 EP 2051 DI 10.1063/1.1476668 PG 9 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 568NR UT WOS:000176549000005 ER PT J AU He, GW Rubinstein, R Wang, LP AF He, GW Rubinstein, R Wang, LP TI Effects of subgrid-scale modeling on time correlations in large eddy simulation SO PHYSICS OF FLUIDS LA English DT Article ID ISOTROPIC TURBULENCE; VISCOSITY; SOUND AB The effects of the unresolved subgrid-scale (SGS) motions on the energy balance of the resolved scales in large eddy simulation (LES) have been investigated actively because modeling the energy transfer between the resolved and unresolved scales is crucial to constructing accurate SGS models. But the subgrid scales not only modify the energy balance, they also contribute to temporal decorrelation of the resolved scales. The importance of this effect in applications including the predictability problem and the evaluation of sound radiation by turbulent flows motivates the present study of the effect of SGS modeling on turbulent time correlations. This paper compares the two-point, two-time Eulerian velocity correlation in isotropic homogeneous turbulence evaluated by direct numerical simulation (DNS) with the correlations evaluated by LES using a standard spectral eddy viscosity. It proves convenient to express the two-point correlations in terms of spatial Fourier decomposition of the velocity field. The LES fields are more coherent than the DNS fields: their time correlations decay more slowly at all resolved scales of motion and both their integral scales and microscales are larger than those of the DNS field. Filtering alone is not responsible for this effect: in the Fourier representation, the time correlations of the filtered DNS field are identical to those of the DNS field itself. The possibility of modeling the decorrelating effects of the unresolved scales of motion by including a random force in the model is briefly discussed. The results could have applications to the problem of computing sound sources in isotropic homogeneous turbulence by LES. (C) 2002 American Institute of Physics. C1 NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. Chinese Acad Sci, Inst Mech, LNM, Beijing 100080, Peoples R China. Univ Delaware, Dept Mech Engn, Spencer Lab 126, Newark, DE 19716 USA. RP He, GW (reprint author), NASA, Langley Res Ctr, ICASE, Mail Stop 132C, Hampton, VA 23681 USA. EM hgw@icase.edu RI Wang, Lian-Ping/N-7516-2016 OI Wang, Lian-Ping/0000-0003-4276-0051 NR 27 TC 53 Z9 59 U1 1 U2 6 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD JUL PY 2002 VL 14 IS 7 BP 2186 EP 2193 DI 10.1063/1.1483877 PG 8 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 568NR UT WOS:000176549000018 ER PT J AU Cruden, BA Rao, MVVS Sharma, SP Meyyappan, M AF Cruden, BA Rao, MVVS Sharma, SP Meyyappan, M TI Optical path length control in plasma absorption measurements SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID REFERENCE CELL AB An inductively coupled Gaseous Electronics Conference (GEC) cell with modified viewing ports has been used to measure in situ absorption in CF4 plasmas via Fourier transform infrared spectroscopy, and the results compared to those obtained in a standard viewport configuration. The viewing ports were modified so that the window boundary is inside, rather than outside, of the GEC cell. Because the absorption obtained is a line of sight integrated absorption, measurements made represent an averaging of absorbing species inside and outside of the plasma. This modification is made to reduce this spatial averaging and thus allow a more accurate estimation of neutral species concentrations and temperatures within the plasmas. By reducing this path length, we find that the apparent CF4 consumption increases from 65% to 95% and the apparent vibrational temperature of CF4 rises by 50-75 K. The apparent fraction of etch product SiF4 decreases from 4% to 2%. The data suggest that these density changes may be due to significant temperature gradients between the plasma and chamber viewports. (C) 2002 American Institute of Physics. C1 NASA, Plasma Res Lab, Ames Res Ctr, Moffett Field, CA 94035 USA. Eloret Corp, Sunnyvale, CA 94087 USA. RP Cruden, BA (reprint author), NASA, Plasma Res Lab, Ames Res Ctr, Mail Stop 223-3, Moffett Field, CA 94035 USA. NR 11 TC 2 Z9 2 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD JUL PY 2002 VL 73 IS 7 BP 2578 EP 2582 DI 10.1063/1.1483898 PG 5 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 566KP UT WOS:000176427500010 ER PT J AU Burt, EA Ekstrom, CR AF Burt, EA Ekstrom, CR TI Optimal three-layer cylindrical magnetic shield sets for scientific applications SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB We present results from modeling axial shielding effectiveness for various configurations of three-layer cylindrical magnetic shield sets. In particular, we examine the effect on shielding of spacing between shield layers, end cap geometry, and end cap holes as well as gaps between mating surfaces. We find that shield spacing is critical and that increased radial spacing continues to improve overall shielding at least up to the point where the ratio of the outer shield diameter to its length approaches 1. The analysis suggests that further increases in shield diameter would improve the shielding, but since this quickly becomes uneconomical, we present an approach that optimizes the cost-benefit ratio of a shield set. Finally, we describe a three-layer shield set design based on this analysis and present results demonstrating an axial shielding effectiveness of 3.5(4)x10(4). (C) 2002 American Institute of Physics. C1 USN Observ, Washington, DC 20392 USA. RP Burt, EA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 15 TC 20 Z9 21 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 JUL PY 2002 VL 73 IS 7 BP 2699 EP 2704 DI 10.1063/1.1487892 PG 6 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 566KP UT WOS:000176427500030 ER PT J AU Grimsley, BW Cano, RJ Hubert, P Loos, AC Song, XL Pipes, RB AF Grimsley, BW Cano, RJ Hubert, P Loos, AC Song, XL Pipes, RB TI Effects of amine and anhydride curing agents on the VARTM matrix processing properties SO SAMPE JOURNAL LA English DT Article AB To ensure successful applications of composite structure for aerospace vehicles, it is necessary to develop material systems that meet a variety of requirements. The industry has recently developed a number of low-viscosity epoxy resins to meet the processing requirements associated with vacuum assisted resin transfer molding (VARTM) of aerospace components. The curing kinetics and viscosity of two of these resins, an amine-cured epoxy system, Applied Poleramic, Inc., VR-56-4((2)), and an anhydride-cured epoxy system, A.TA.R.D. Laboratories SI-ZG-5A, have been characterized for application in the VARTM process. Simulations were carried out using the process model, COMPRO(C) to examine heat transfer curing kinetics and viscosity for different panel thicknesses and cure cycles. Results of these simulations indicate that the two resins have significantly different curing behaviors and flow characteristics. C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. Old Dominion Univ, Norfolk, VA USA. Virginia Polytech Inst & State Univ, Blacksburg, VA 24061 USA. Univ Akron, Akron, OH 44325 USA. RP Grimsley, BW (reprint author), NASA, Langley Res Ctr, Hampton, VA 23665 USA. NR 13 TC 3 Z9 3 U1 0 U2 1 PU SAMPE PUBLISHERS PI COVINA PA 1161 PARKVIEW DRIVE, COVINA, CA 91722 USA SN 0091-1062 J9 SAMPE J JI Sampe J. PD JUL-AUG PY 2002 VL 38 IS 4 BP 8 EP 15 PG 8 WC Engineering, Multidisciplinary; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 570DT UT WOS:000176643900003 ER PT J AU Delin, KA AF Delin, KA TI The Sensor Web: A macro-instrument for coordinated sensing SO SENSORS LA English DT Article DE Sensor web; distributed; network; smart sensors; wireless ID NETWORKS AB The Sensor Web is a macro-instrument concept that allows for the spatiotemporal understanding of an environment through coordinated efforts between multiple numbers and types of sensing platforms, including both orbital and terrestrial and both fixed and mobile. Each of these platforms, or pods, communicates within their local neighborhood and thus distributes information to the instrument as a whole. Much as intelligence in the brain is a result of the myriad of connections between dendrites, it is anticipated that the Sensor Web will develop a macro-intelligence as a result of its distributed information with the pods reacting and adapting to their environment in a way that is much more than their individual sum. The sharing of data among individual pods will allow for a global perception and purpose of the instrument as a whole. The Sensor Web is to sensors what the Internet is to computers, with different platforms and operating systems communicating via a set of shared, robust protocols. This paper will outline the potential of the Sensor Web concept and describe the Jet Propulsion Laboratory (JPL) Sensor Webs Project (http://sensorwebs.jpl.nasa.gov/). In particular, various fielded Sensor Webs will be discussed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Delin, KA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 TC 65 Z9 67 U1 0 U2 8 PU MOLECULAR DIVERSITY PRESERVATION INTERNATIONAL PI BASEL PA MATTHAEUSSTRASSE 11, CH-4057 BASEL, SWITZERLAND SN 1424-8220 J9 SENSORS JI Sensors PD JUL PY 2002 VL 2 IS 7 BP 270 EP 285 DI 10.3390/s20700270 PG 16 WC Chemistry, Analytical; Electrochemistry; Instruments & Instrumentation SC Chemistry; Electrochemistry; Instruments & Instrumentation GA 667EF UT WOS:000182217600003 ER PT J AU Sutter, B Wasowicz, T Howard, T Hossner, LR Ming, DW AF Sutter, B Wasowicz, T Howard, T Hossner, LR Ming, DW TI Characterization of iron, manganese, and copper synthetic hydroxyapatites by electron paramagnetic resonance spectroscopy SO SOIL SCIENCE SOCIETY OF AMERICA JOURNAL LA English DT Article ID FLUORIDE GLASSES; FE3+ IONS; X-BAND; EPR; ZEOLITES; SPECTRA; ESR; REACTIVITY; PROTEINS; LOCATION AB The incorporation of micronutrients (e.g., Fe, Mn, Cu) into synthetic hydroxyapatite (SHA) is proposed for slow release of these nutrients to crops in NASA's Advanced Life Support (ALS) program for long-duration space missions. Separate Fe3+ (Fe-SHA), Mn2+ (Mn-SHA), and Cu2+ (Cu-SHA) containing SHA materials were synthesized by a precipitation method. Electron paramagnetic resonance (EPR) spectroscopy was used to determine the location of Fe3+, Mn2+, and Cu2+ ions in the SHA structure and to identify other Fe3+-, Mn2+-, and Cu2+-containing phases that formed during precipitation. The EPR parameters for Fe3+ (g = 4.20 and 8.93) and for Mn2+ (g = 2.01, A = 9.4 mT, D = 39.0 mT and E = 10.5 mT) indicated that Fe3+ and Mn2+ possessed rhombic ion crystal fields within the SHA structure. The Cu2+ EPR parameters (g(z) = 2.488, A(z) = 5.2 mT) indicated that Cu2+ was coordinated to more than six oxygens. The rhombic environments of Fe3+ and Mn2+ along with the unique Cu2+ environment suggested that these metals substituted for the 7 or 9 coordinate Ca2+ in SHA. The EPR analyses also detected poorly crystalline meta oxyhydroxides or metal-phosphates associated with SHA. The Fe-, Mn-, and Cu-SHA materials are potential slow release sources of Fe, Mn, and Cu for ALS and terrestrial cropping systems. C1 NASA, Ames Res Ctr, Natl Res Council, Moffett Field, CA 94035 USA. Georgia State Univ, Dept Phys & Astron, Atlanta, GA 30303 USA. Texas A&M Univ, Dept Chem, College Stn, TX 77843 USA. Texas A&M Univ, Dept Soil & Crop Sci, College Stn, TX 77843 USA. NASA, Johnson Space Ctr, Houston, TX 77058 USA. RP Sutter, B (reprint author), NASA, Ames Res Ctr, Natl Res Council, Moffett Field, CA 94035 USA. NR 58 TC 20 Z9 20 U1 3 U2 14 PU SOIL SCI SOC AMER PI MADISON PA 677 SOUTH SEGOE ROAD, MADISON, WI 53711 USA SN 0361-5995 J9 SOIL SCI SOC AM J JI Soil Sci. Soc. Am. J. PD JUL-AUG PY 2002 VL 66 IS 4 BP 1359 EP 1366 PG 8 WC Soil Science SC Agriculture GA 569ET UT WOS:000176588300032 PM 12817564 ER PT J AU Gumbricht, T McCarthy, TS McCarthy, J Roy, D Frost, PE Wessels, K AF Gumbricht, T McCarthy, TS McCarthy, J Roy, D Frost, PE Wessels, K TI Remote sensing to detect sub-surface peat fires and peat fire scars in the Okavango Delta, Botswana SO SOUTH AFRICAN JOURNAL OF SCIENCE LA English DT Article ID INITIATIVE SAFARI 2000; ALGORITHM; IMAGES; MODIS AB As a consequence of the constantly shifting water distribution in the Okavango Delta, Botswana, peat accumulated in former wetlands adjacent to receding channels is consumed by fire in successive layers as the peat desiccates. Burning peat has been recorded around the dying Thaoge channel since the mid-19th century. In this study, five different remote sensors were used to detect peat fires in and around the Okavango Delta. ATSR data were used to study the annual cycle from 1999 to 2000, AVHRR data and MODIS data were used to monitor the 2000 fire season, and the MODIS Airborne Simulator and Landsat ETM data were employed for high-resolution studies of single fire events. Peat fires were detected using absolute thresholds in the mid-infrared spectrum, the difference between mid and thermal infrared brightness temperatures, and a threshold in the visible to near-infrared spectrum. Lower thresholds than normally used had to be adopted to detect the fires, which led to an overestimation of fires over other areas. The MODIS Airborne Simulator successfully identified the state of peat fires. Making use of a standard fixed threshold, active-fire detection algorithms, ATSR, AVHRR and MODIS data identified only intense surface fires. Peat fires were distinguished only by using a priori knowledge of either spatial distributions or temporal history. Landsat ETM data could not be used to detect these fires. The peat fires have an annual cycle, with a maximum during the dry winter, coinciding with the surface fire season, and a dormant state during the wet summer. Night-time imagery was necessary to detect sub-surface fires. The present area of peat fires in the Okavango is approximately 100 km(2), which is expected to make negligible contributions to regional trace gas and particulate emissions. C1 Univ Witwatersrand, Dept Geol, ZA-2050 Wits, South Africa. Royal Inst Technol, Dept Land & Water Resources Engn, S-10044 Stockholm, Sweden. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland, Dept Geog, College Pk, MD 20742 USA. Inst Soil Climate & Water, ZA-0001 Pretoria, South Africa. RP McCarthy, TS (reprint author), Univ Witwatersrand, Dept Geol, Private Bag 3, ZA-2050 Wits, South Africa. EM mccarthyt@geosciences.wits.ac.za NR 26 TC 13 Z9 15 U1 1 U2 6 PU ACAD SCIENCE SOUTH AFRICA A S S AF PI LYNWOOD RIDGE PA PO BOX 72135, LYNWOOD RIDGE 0040, SOUTH AFRICA SN 0038-2353 J9 S AFR J SCI JI S. Afr. J. Sci. PD JUL-AUG PY 2002 VL 98 IS 7-8 BP 351 EP 358 PG 8 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 612KR UT WOS:000179074700014 ER PT J AU Bauschlicher, CW Gutsev, GL AF Bauschlicher, CW Gutsev, GL TI The electron affinities of transition metal atoms at the CCSD(T) and density functional levels of theory SO THEORETICAL CHEMISTRY ACCOUNTS LA English DT Article DE density functional theory; CCSD(T); electron affinities ID COUPLED-CLUSTER THEORY; GAUSSIAN-BASIS SETS; EXCITATION-ENERGIES; HARTREE-FOCK; ROW ATOMS; APPROXIMATION; EXCHANGE; SYSTEMS; SPECTRA; SPIN AB The electron affinities of Ti, V, Cr, Fe, Co, Ni. and Cu are computed using the density function theory and CCSD(T) approaches. Overall the CCSD(T) approach yields the best results. For this property, the B3LYP, BLYP, and BP86 functionals perform better than the BPW91, PBEPBE, and PBE1PBE ones. The accuracy of all the methods is higher if the number of 3d electrons is the same in the neutral atom and the anion. This is especially true for the density functional theory methods. C1 NASA, Ames Res Ctr, Space Technol Div, Moffett Field, CA 94035 USA. Univ Virginia, Dept Chem, Charlottesville, VA 22901 USA. RP Bauschlicher, CW (reprint author), NASA, Ames Res Ctr, Space Technol Div, Mail Stop 230-3, Moffett Field, CA 94035 USA. NR 37 TC 24 Z9 24 U1 0 U2 4 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 1432-881X J9 THEOR CHEM ACC JI Theor. Chem. Acc. PD JUL PY 2002 VL 108 IS 1 BP 27 EP 30 DI 10.1007/s00214-002-0343-0 PG 4 WC Chemistry, Physical SC Chemistry GA 584XM UT WOS:000177494100004 ER PT J AU Alanou, MP Snidle, RW Evans, HP Krantz, TL AF Alanou, MP Snidle, RW Evans, HP Krantz, TL TI On the performance of thin hard coatings for gearing applications SO TRIBOLOGY TRANSACTIONS LA English DT Article DE aerospace tribology; jet engine oils; surface roughness; scoring; scuffing ID BORON-CARBIDE COATINGS; TRIBOLOGICAL PROPERTIES; DLC COATINGS; FILMS; DEPOSITION; BEHAVIOR; FAILURE; MODEL; STEEL AB Thin hard coatings are possible candidates,for the enhancement of scuffing and micro-pitting preformance of gears. They exhibit very high levels of surface hardness (typically 1000 HV) combined with a low traction coefficient (typically 0.2) against dry steel. The paper presents the results of an experimental program carried out in order to assess the scuffing performance of thin hard coatings for various combinations of substrates and surface finish under realistic engineering conditions of sliding speed, oil temperature and contact pressure. Two types of coating were assessed: diamond like carbon (DLC) coatings and boron carbide coatings. Although the overall performance improvement is promising, caution may be required when using thin hard coatings with case carburised substrates where adhesion problems may occur. Their use with nitrided steel as a substrate seems to be particularly advantageous, possibly because a higher process temperature may be used. The coatings tested also gave better performance at relatively low sliding speeds (less than or equal to 16 m/s), At higher levels of sliding the predominant effect is one of lubrication failure, the material parameter becoming secondary. C1 Univ Wales Coll Cardiff, Sch Engn, Cardiff CF24 0YF, S Glam, Wales. NASA, Glenn Res Ctr, Army Res Lab, Cleveland, OH USA. RP Alanou, MP (reprint author), Univ Wales Coll Cardiff, Sch Engn, Cardiff CF24 0YF, S Glam, Wales. NR 27 TC 12 Z9 12 U1 0 U2 5 PU TAYLOR & FRANCIS INC PI PHILADELPHIA PA 325 CHESTNUT ST, SUITE 800, PHILADELPHIA, PA 19106 USA SN 1040-2004 J9 TRIBOL T JI Tribol. Trans. PD JUL PY 2002 VL 45 IS 3 BP 334 EP 344 DI 10.1080/10402000208982558 PG 11 WC Engineering, Mechanical SC Engineering GA 575JE UT WOS:000176942500009 ER PT J AU Liu, JP Martinson, DG Yuan, XJ Rind, D AF Liu, JP Martinson, DG Yuan, XJ Rind, D TI Evaluating Antarctic sea ice variability and its teleconnections in global climate models SO INTERNATIONAL JOURNAL OF CLIMATOLOGY LA English DT Article DE Antarctic sea ice edge; global climate models; teleconnection patterns; ENSO bellingshausen; Amundsen, Ross and Weddell Seas ID SOUTHERN OSCILLATION; SYSTEM-MODEL; OCEAN; TEMPERATURE; EXTENT; SENSITIVITY; ASYMMETRY; LAYER AB This study evaluates simulated Antarctic sea ice edge (SIE) variability and its teleconnections in three global coupled climate models (GISS, NCAR and GFDL) against the observations. All models do a reasonable job in simulating the seasonal advance and retreat of the Antarctic sea ice fields. The simulated GISS and NCAR SIE distributions are in agreement with observations in summer and autumn, whereas the GFDL model does best in spring and winter. A common problem is the poor simulation of the observed SIE in the Weddell Sea. All models are not particularly good at simulating the observed regionally varying SIE trends. A comparison of dominant empirical orthogonal function modes of surface air temperature (SAT) variability in each model associated with observed modes show that the models generally capture features of the more prominent covarying spatial patterns such as an El Nino-southern oscillation (ENSO)-like pattern in the tropical Pacific. The simulated teleconnection patterns between detrended Antarctic SIE anomalies and detrended global SAT anomalies in each model are evaluated for comparison with observed teleconnection patterns. All models capture the ENSO-like phenomenon to some degree. Also, the GISS and NCAR models capture the Antarctic dipole pattern and meridional banding structure through the Pacific. The Antarctic SIE regions showing the strongest extrapolar teleconnections differ among the models and between the models and observations. Almost all models miss the observed polar-extrapolar teleconnections in the central Indian, western extreme of the tropical and southern Pacific, and over the tropical continents. Copyright (C) 2002 Royal Meteorological Society. C1 NASA, Goddard Space Flight Ctr, Inst Space Studies, New York, NY 10025 USA. Columbia Univ, Dept Earth & Environm Sci, Palisades, NY 10964 USA. Columbia Univ, Lamont Doherty Earth Observ, Palisades, NY 10964 USA. RP Liu, JP (reprint author), NASA, Goddard Space Flight Ctr, Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. RI LIU, JIPING/N-6696-2016 NR 41 TC 15 Z9 17 U1 0 U2 2 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 JUN 30 PY 2002 VL 22 IS 8 BP 885 EP 900 DI 10.1002/joc.770 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 570KA UT WOS:000176656400001 ER PT J AU Wilson, A Bozzolo, G Noebe, RD Howe, JM AF Wilson, A Bozzolo, G Noebe, RD Howe, JM TI Experimental verification of the theoretical prediction of the phase structure of a Ni-Al-Ti-Cr-Cu alloy SO ACTA MATERIALIA LA English DT Article DE NiAl alloys; intermetallic; transmission electron microscopy (TEM); atomistic modeling; BFS method; Monte Carlo simulations ID MECHANICAL-PROPERTIES; ADDITIONS; SURFACES; SYSTEMS AB The Bozzolo-Ferrante-Smith (BFS) method for alloys was applied to the study of NiAl-based materials to assess the effect of alloying additions on structure. Ternary, quaternary and even pentalloys based on NiAl with additions of Ti, Cr and Cu were studied and experimental verification of the theoretical predictions including the phase structure of a Ni-Al-Ti-Cr-Cu alloy is presented. Two approaches were used, Monte Carlo simulations to determine low energy structures, and analytical calculations of the energy of high symmetry configurations which give physical insight into preferred structures. The energetics for site occupancy in ternary and quaternary systems were calculated leading to an indirect determination of solubility limits at 0 K. Precipitate formation with information concerning structure and lattice parameter were also 'observed' computationally and the general characteristics of a Ni-Al-Ti-Cr-Cu alloy were correctly predicted. The results indicate that the BFS method for alloys can be a useful tool for alloy design and can be used to complement experimental alloy design programs. (C) 2002 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved. C1 Ohio Aerosp Inst, Cleveland, OH 44142 USA. USN, Res Lab, Washington, DC 20375 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Univ Virginia, Dept Mat Sci & Engn, Charlottesville, VA 22903 USA. RP Bozzolo, G (reprint author), Ohio Aerosp Inst, 22800 Cedar Point Rd, Cleveland, OH 44142 USA. EM guillermo.h.bozzolo@grc.nasa.gov NR 21 TC 14 Z9 15 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 EI 1873-2453 J9 ACTA MATER JI Acta Mater. PD JUN 28 PY 2002 VL 50 IS 11 BP 2787 EP 2800 AR PII S1359-6454(02)00095-2 DI 10.1016/S1359-6454(02)00095-2 PG 14 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 576GD UT WOS:000176994000003 ER PT J AU Cody, RJ Payne, WA Thorn, RP Nesbitt, FL Iannone, MA Tardy, DC Stief, LJ AF Cody, RJ Payne, WA Thorn, RP Nesbitt, FL Iannone, MA Tardy, DC Stief, LJ TI Rate constant for the recombination reaction CH3+CH3 -> C2H6 at T=298 and 202 K SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID METHYL RADICAL RECOMBINATION; ABSOLUTE RATE-CONSTANT; TEMPERATURE-DEPENDENCE; ENERGY-TRANSFER; KINETICS; PRESSURE; CH3; ATOMS; VINYL AB The recombination of methyl radicals is the major loss process for methyl in the atmospheres of Saturn and Neptune. The serious disagreement between observed and calculated levels of CH3 has led to suggestions that the atmospheric models greatly underestimated the loss of CH3 due to poor knowledge of the rate of the reaction CH3 + CH3 + M - C2H6 + M at the low temperatures and pressures of these atmospheric systems. In an attempt to resolve this problem, the absolute rate constant for the self-reaction of CH3 has been measured using the discharge-flow kinetic technique coupled to mass spectrometric detection at T = 202 and 298 K and P = 0.6-2.0 Torr nominal pressure (He). CH3 was produced by the reaction of F with CH4, with [CH4] in large excess over [F], and detected by low energy (11 eV) electron impact ionization at m/Z = 15. The results were obtained by graphical analysis of plots of the reciprocal of the CH3 signal vs reaction time. At T = 298 K, k(1)(0.6 Torr) = (2.15 +/- 0.42) x 10(-11) cm(3) molecule(-1) s(-1) and k(1)(I Tort) = (2.44 +/- 0.52) x 10(-11) cm(3) molecule(-1) s(-1). At T = 202 K, the rate constant increased from k(1)(0.6 Torr) = (5.04 +/- 1.15) x 10(-11) cm(3) molecule(-1) s(-1) to k(1)(1.0 Torr) = (5.25 +/- 1.43) x 10(-11) cm(3) molecule(-1) s(-1) to k(1)(2.0 Torr) = (6.52 +/- 1.54) x 10(-11) cm(3) molecule(-1) s(-1), indicating that the reaction is in the falloff region. Klippenstein and Harding had previously calculated rate constant falloff curves for this self-reaction in At buffer gas. Transforming these results for a He buffer gas suggest little change in the energy removal per collision, -(d), With decreasing temperature and also indicate that - (d) for He buffer gas is approximately half of that for Argon. Since the experimental results seem to at least partially affirm the validity of the Klippenstein and Harding calculations, we suggest that, in atmospheric models of the outer planets, use of the theoretical results for k(1) is preferable to extrapolation of laboratory data to pressures and temperatures well beyond the range of the experiments. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. Coppin State Coll, Dept Nat Sci, Baltimore, MD 21216 USA. Millersville Univ Pennsylvania, Dept Chem, Millersville, PA 17551 USA. Univ Iowa, Dept Chem, Iowa City, IA 52242 USA. RP Cody, RJ (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Code 691, Greenbelt, MD 20771 USA. RI Cody, Regina/D-5996-2013 NR 36 TC 23 Z9 23 U1 1 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD JUN 27 PY 2002 VL 106 IS 25 BP 6060 EP 6067 DI 10.1021/jp0140441 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 565EQ UT WOS:000176356400013 ER PT J AU Eto, S Isobe, H Narukage, N Asai, A Morimoto, T Thompson, B Yashiro, S Wang, TJ Kitai, R Kurokawa, H Shibata, K AF Eto, S Isobe, H Narukage, N Asai, A Morimoto, T Thompson, B Yashiro, S Wang, TJ Kitai, R Kurokawa, H Shibata, K TI Relation between a Moreton wave and an EIT wave observed on 1997 November 4 SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN LA English DT Article DE Sun : chromosphere; Sun : corona; Sun : flares; Sun : MHD ID RADIO-BURSTS; TELESCOPE; MODEL AB We consider the relationship between two flare-associated waves, a chromospheric Moreton wave and a coronal EIT wave, based on an analysis of an X-class flare event in AR 8 100 on 1997 November 4. A Moreton wave was observed in Halpha, Halpha + 0.8 Angstrom, and Halpha - 0.8 Angstrom with the Flare-Monitoring Telescope (FMT) at the Hida Observatory. An EIT wave was observed in EUV with the Extreme ultraviolet Imaging Telescope (EIT) on board SOHO. The propagation speeds of the Moreton wave and the EIT wave were approximately 715 kin s(-1) and 202 km s(-1), respectively. The times of visibility For the Moreton wave did not overlap those of the EIT wave, but the continuation of the former is indicated by a filament oscillation. Data on the speed and location clearly show that the Moreton wave differed physically from the EIT wave in this case. The Moreton wave preceded the EIT wave, which is inconsistent with an identification of the EIT wave with a fast-mode MHD shock. C1 Kyoto Univ, Dept Astron, Sakyo Ku, Kyoto 6068502, Japan. Kyoto Univ, Kwasan & Hida Observ, Kyoto 6078471, Japan. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Max Planck Inst Aeron, D-37191 Katlenburg Lindau, Germany. RP Kyoto Univ, Dept Astron, Sakyo Ku, Kyoto 6068502, Japan. EM eto@kusastro.kyoto-u.ac.jp RI Thompson, Barbara/C-9429-2012 NR 26 TC 80 Z9 81 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 JUN 25 PY 2002 VL 54 IS 3 BP 481 EP 491 DI 10.1093/pasj/54.3.481 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 569PL UT WOS:000176611000017 ER PT J AU Wielicki, BA Del Genio, AD Wong, TM Chen, JY Carlson, BE Allan, RP Robertson, F Jacobowitz, H Slingo, A Randall, DA Kiehl, JT Soden, BJ Gordon, CT Miller, AJ Yang, SK Susskind, J AF Wielicki, BA Del Genio, AD Wong, TM Chen, JY Carlson, BE Allan, RP Robertson, F Jacobowitz, H Slingo, A Randall, DA Kiehl, JT Soden, BJ Gordon, CT Miller, AJ Yang, SK Susskind, J TI Changes in tropical clouds and radiation - Response SO SCIENCE LA English DT Editorial Material C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Columbia Univ, Dept Earth & Environm Sci, Palisades, NY 10964 USA. Met Off, Hadley Ctr, Bracknell RG12 2SY, Berks, England. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NOAA, NESDIS, Camp Springs, MD 20746 USA. Colorado State Univ, Ft Collins, CO 80523 USA. Natl Ctr Atmospher Res, Boulder, CO 80303 USA. Princeton Univ, NOAA, GFDL, Princeton, NJ 08542 USA. NOAA, Climate Predict Ctr, NCEP, Camp Springs, MD 20746 USA. NASA, Goddard Space Flight Ctr, Huntsville, AL 35812 USA. RP Wielicki, BA (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. RI Allan, Richard/B-5782-2008; Del Genio, Anthony/D-4663-2012 OI Allan, Richard/0000-0003-0264-9447; Del Genio, Anthony/0000-0001-7450-1359 NR 4 TC 8 Z9 8 U1 0 U2 0 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD JUN 21 PY 2002 VL 296 IS 5576 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 565PQ UT WOS:000176379000002 ER PT J AU Cutten, DR Rothermel, J Jarzembski, MA Hardesty, RM Howell, JN Tratt, DM Srivastava, V AF Cutten, DR Rothermel, J Jarzembski, MA Hardesty, RM Howell, JN Tratt, DM Srivastava, V TI Radiometric calibration of an airborne CO2 pulsed Doppler lidar with a natural Earth surface SO APPLIED OPTICS LA English DT Article ID ATMOSPHERIC WIND SENSOR; AEROSOL BACKSCATTER; TARGET; WAVELENGTHS AB Radiometric calibration of an airborne CO2 pulsed Doppler lidar has been accomplished with surface retroreflection signals from the White Sands National Monument, New Mexico. Two circular passes were made at altitudes of 6.3 and 9.3 km. The computed calibration factors for both altitudes are in excellent agreement with the value derived from standard ground-based measurements involving a fixed sandpaper target of known reflectance. This finding corroborates a previous study that successfully calibrated an airborne cw Doppler lidar with a variety of natural Earth surfaces. The present results indicate that relatively uniform Earth surface targets can be used for in-flight calibration of CO pulsed airborne and, in principal, other infrared lidars. (C) 2002 Optical Society of America. C1 Univ Alabama, Global & Hydrol & Climate Ctr, Huntsville, AL 35805 USA. NASA, Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NOAA, Environm Res Lab, Boulder, CO 80305 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Space Res Assoc, Global Hydrol & Climate Ctr, Huntsville, AL 35805 USA. RP Univ Alabama, Global & Hydrol & Climate Ctr, 320 Sparkman Dr, Huntsville, AL 35805 USA. EM dean.cutten@msfc.nasa.gov RI Tratt, David/A-7884-2009; Hardesty, Robert/H-9844-2013 OI Tratt, David/0000-0002-3942-6848; NR 16 TC 3 Z9 4 U1 0 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD JUN 20 PY 2002 VL 41 IS 18 BP 3530 EP 3537 DI 10.1364/AO.41.003530 PG 8 WC Optics SC Optics GA 563UJ UT WOS:000176274200006 PM 12078677 ER PT J AU Veselovskii, I Kolgotin, A Griaznov, V Muller, D Wandinger, U Whiteman, DN AF Veselovskii, I Kolgotin, A Griaznov, V Muller, D Wandinger, U Whiteman, DN TI Inversion with regularization for the retrieval of tropospheric aerosol parameters from multiwavelength lidar sounding SO APPLIED OPTICS LA English DT Article ID MICROPHYSICAL PARTICLE PARAMETERS; ELASTIC-BACKSCATTER LIDAR; RAMAN LIDAR; SIZE DISTRIBUTION; 6-WAVELENGTH LIDAR; LIQUID WATER; EXTINCTION; DISTRIBUTIONS; SIMULATION; ATMOSPHERE AB We present an inversion algorithm for the retrieval of particle size distribution parameters, i.e., mean (effective) radius, number, surface area, and volume concentration, and complex refractive index from multiwavelength lidar data. In contrast to the classical Tikhonov method, which accepts only that solution for which the discrepancy reaches its global minimum. in our algorithm we perform the averaging of solutions in the vicinity of this minimum, This averaging stabilizes the underlying ill-posed inverse problem, particularly with respect to the retrieval of number concentration. Results show that, for typical tropospheric particles and 10% error in the optical data, the mean radius could be retrieved to better than 20% from a lidar on the basis of a Nd:YAG laser, which provides a combination of backscatter coefficients at 355, 532, and 1064 nm and extinction coefficients at 355 and 532 nm. The accuracy is improved if the lidar is also equipped with a hydrogen Raman shifter. In this case two additional backscatter coefficients at 416 and 683 nm are available. The combination of two extinction coefficients and five backscatter coefficients then allows one to retrieve not only averaged aerosol parameters but also the size distribution function. There was acceptable agreement between physical particle properties obtained from the evaluation of multiwavelength lidar data taken during the Lindenberg Aerosol Characterization Experiment in 1998 (LACE 98) and in situ data, which were taken aboard aircraft. (C) 2002 Optical Society of America. C1 Inst Gen Phys, Phys Instrumentat Ctr, Troitsk 142190, Moscow Region, Russia. Inst Tropospher Res, D-04318 Leipzig, Germany. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Inst Gen Phys, Phys Instrumentat Ctr, Troitsk 142190, Moscow Region, Russia. EM katyv@orc.ru; detlef@tropos.de; ulla@tropos.de RI Wandinger, Ulla/E-3348-2014; MUELLER, DETLEF/F-1010-2015 OI MUELLER, DETLEF/0000-0002-0203-7654 NR 46 TC 143 Z9 149 U1 0 U2 6 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD JUN 20 PY 2002 VL 41 IS 18 BP 3685 EP 3699 DI 10.1364/AO.41.003685 PG 15 WC Optics SC Optics GA 563UJ UT WOS:000176274200025 PM 12078696 ER PT J AU McGill, M Hlavka, D Hart, W Scott, VS Spinhirne, J Schmid, B AF McGill, M Hlavka, D Hart, W Scott, VS Spinhirne, J Schmid, B TI Cloud Physics Lidar: instrument description and initial measurement results SO APPLIED OPTICS LA English DT Article ID MICROPHYSICAL PROPERTIES; TROPOSPHERIC AEROSOL; AIRBORNE LIDAR; CIRRUS; PARAMETERS; SUCCESS AB The new Cloud Physics Lidar (CPL) has been built for use on the NASA ER-2 high-altitude aircraft. The purpose of the CPL is to provide multiwavelength measurements of cirrus, subvisual cirrus, and aerosols with high temporal and spatial resolution. The CPL utilizes state-of-the-art technology, with a high repetition rate, a low-pulse-energy laser, and photon-counting detection. The first deployment for the CPL was the Southern African Regional Science Initiative's 2000 field campaign during August and September 2000. We provide here an overview of the instrument and initial data results to illustrate the measurement capability of the CPL. (C) 2002 Optical Society of America. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Sci Syst & Applicat Inc, Lanham, MD 20706 USA. Bay Area Enivironm Res Inst, Sonoma, CA 95476 USA. RP NASA, Goddard Space Flight Ctr, Code 912, Greenbelt, MD 20771 USA. EM mcgill@virl.gsfc.nasa.gov RI McGill, Matthew/D-8176-2012; Scott, Vibart/B-5086-2013; OI Hlavka, Dennis/0000-0002-2976-7243 NR 17 TC 108 Z9 112 U1 0 U2 2 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD JUN 20 PY 2002 VL 41 IS 18 BP 3725 EP 3734 DI 10.1364/AO.41.003725 PG 10 WC Optics SC Optics GA 563UJ UT WOS:000176274200028 PM 12078699 ER PT J AU Kawasaki, MT Ozaki, M Nagase, F Masai, K Ishida, M Petre, R AF Kawasaki, MT Ozaki, M Nagase, F Masai, K Ishida, M Petre, R TI ASCA observations of the supernova remnant IC 443: Thermal structure and detection of overionized plasma SO ASTROPHYSICAL JOURNAL LA English DT Article DE conduction; ISM : individual (IC 443); plasmas; radiation mechanisms : thermal; supernova remnants ID X-RAY-EMISSION; FORMED DENSE SHELL; MODELING W44; HOT INTERIOR; IC-443; CONDUCTION; NORTHEAST; GRADIENT; CLOUDS; IC443 AB We present the results of X-ray spatial and spectral studies of the mixed-morphology supernova remnant IC 443 using ASCA. IC 443 has a center-filled image in the X-ray band, contrasting with the shell-like appearance in radio and optical bands. The overall X-ray emission is thermal, not from a synchrotron nebula. We observed IC 443 three times with ASCA, covering the whole remnant. From the image analysis, we find that the softness-ratio map reveals a shell-like structure. At the same time, its spectra require two (1.0 and 0.2 keV) plasma components; the emission of the 0.2 keV plasma is stronger in the region near the shell than in the center. These results can be explained by a simple model that IC 443 has a hot ( 1.0 keV) interior surrounded by a cool ( 0.2 keV) outer shell. From the emission measures, we infer that the 0.2 keV plasma is denser than the 1.0 keV plasma, suggesting pressure equilibrium between the two. In addition, we find that the ionization temperature of sulfur, obtained from the H-like to He-like K intensity ratio, is 1.5 keV, significantly higher than the gas temperature of 1.0 keV suggested from the continuum spectrum. The same can be concluded for silicon. Neither an additional, hotter plasma component nor a multitemperature plasma successfully account for this ratio, and we conclude that the 1.0 keV plasma is overionized. This is the first time that overionized gas has been detected in a supernova remnant (SNR). For the gas to become overionized in the absence of a photoionizing flux, it must cool faster than the ions recombine. Thermal conduction from the 1.0 keV plasma to the 0.2 keV plasma could cause the 1.0 keV plasma to become overionized, which is plausible within an old (3 x 10(4) yr) SNR. C1 Inst Space & Astronaut Sci, Kanagawa 2298510, Japan. Tokyo Metropolitan Univ, Dept Phys, Tokyo 1920397, Japan. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Kawasaki, MT (reprint author), Inst Space & Astronaut Sci, 3-1-1 Yoshinodai, Kanagawa 2298510, Japan. RI Ozaki, Masanobu/K-1165-2013 NR 29 TC 50 Z9 51 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 20 PY 2002 VL 572 IS 2 BP 897 EP 905 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 560FC UT WOS:000176071200017 ER PT J AU Pun, CSJ Michael, E Zhekov, SA McCray, R Garnavich, PM Challis, PM Kirshner, RP Baron, E Branch, D Chevalier, RA Filippenko, AV Fransson, C Leibundgut, B Lundqvist, P Panagia, N Phillips, MM Schmidt, B Sonneborn, G Suntzeff, NB Wang, LF Wheeler, JC AF Pun, CSJ Michael, E Zhekov, SA McCray, R Garnavich, PM Challis, PM Kirshner, RP Baron, E Branch, D Chevalier, RA Filippenko, AV Fransson, C Leibundgut, B Lundqvist, P Panagia, N Phillips, MM Schmidt, B Sonneborn, G Suntzeff, NB Wang, LF Wheeler, JC TI Modeling the Hubble Space Telescope ultraviolet and optical spectrum of spot 1 on the circumstellar ring of SN 1987A SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; supernova remnants; supernovae : individual (SN 1987A) ID LARGE-MAGELLANIC-CLOUD; RADIATIVE SHOCK-WAVES; VELOCITY LY-ALPHA; X-RAY; INTERSTELLAR EXTINCTION; SUPERNOVA REMNANT; NEUTRINO BURST; EMISSION-LINES; RADIO REMNANT; H-ALPHA AB We report and interpret Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph ( STIS) long-slit observations of the optical and ultraviolet ( 1150 10270 A) emission line spectra of the rapidly brightening spot 1 on the equatorial ring of SN 1987A between 1997 September and 1999 October ( days 3869 4606 after outburst). The emission is caused by radiative shocks created where the supernova blast wave strikes dense gas protruding inward from the equatorial ring. We measure and tabulate line identifications, fluxes, and, in some cases, line widths and shifts. We compute flux correction factors to account for substantial interstellar line absorption of several emission lines. Nebular analysis shows that optical emission lines come from a region of cool (T-e approximate to10(4) K) and dense (n(e) approximate to10(6) cm(-3)) gas in the compressed photoionized layer behind the radiative shock. The observed line widths indicate that only shocks with shock velocities V-s < 250 km s(-1) have become radiative, while line ratios indicate that much of the emission must have come from yet slower (V-s &LSIM; 135 km s(-1)) shocks. Such slow shocks can be present only if the protrusion has atomic density n &GSIM; 3 x 10(4) cm(-3), somewhat higher than that of the circumstellar ring. We are able to fit the UV fluxes with an idealized radiative shock model consisting of two shocks (V-s = 135 and 250 km s(-1)). The observed UV flux increase with time can be explained by the increase in shock surface areas as the blast wave overtakes more of the protrusion. The observed flux ratios of optical to highly ionized UV lines are greater by a factor of &SIM;2-3 than predictions from the radiative shock models, and we discuss the possible causes. We also present models for the observed Hα line widths and profiles, which suggest that a chaotic flow exists in the photoionized regions of these shocks. We discuss what can be learned with future observations of all the spots present on the equatorial ring. C1 Natl Opt Astron Observ, Tucson, AZ 85726 USA. NASA, Goddard Space Flight Ctr, Lab Astron & Space Phys, Greenbelt, MD 20771 USA. Univ Colorado, JILA, Boulder, CO 80309 USA. Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Oklahoma, Dept Phys & Astron, Norman, OK 73019 USA. Univ Virginia, Dept Astron, Charlottesville, VA 22903 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Stockholm Observ, SCFAB, Dept Astron, SE-10691 Stockholm, Sweden. European So Observ, D-85784 Garching, Germany. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Las Campanas Observ, Carnegie Inst Washington, La Serena, Chile. Mt Stromlo & Siding Spring Observ, Canberra, ACT 2611, Australia. Cerro Tololo Interamer Observ, La Serena, Chile. EO Lawrence Berkeley Natl Lab, Inst Nucl & Particle Astrophys, Berkeley, CA 94720 USA. Univ Texas, Dept Astron, Austin, TX 78712 USA. RP Pun, CSJ (reprint author), Univ Hong Kong, Dept Phys, 518 Chong Yuet Ming Phys Bldg,Pokfulam Rd, Hong Kong, Hong Kong, Peoples R China. RI Baron, Edward/A-9041-2009; OI Baron, Edward/0000-0001-5393-1608; Schmidt, Brian/0000-0001-6589-1287; Schmidt, Brian/0000-0002-8538-9195 NR 81 TC 50 Z9 50 U1 0 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 20 PY 2002 VL 572 IS 2 BP 906 EP 931 DI 10.1086/340453 PN 1 PG 26 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 560FC UT WOS:000176071200018 ER PT J AU Elsner, RF Gladstone, GR Waite, JH Crary, FJ Howell, RR Johnson, RE Ford, PG Metzger, AE Hurley, KC Feigelson, ED Garmire, GP Bhardwaj, A Grodent, DC Majeed, T Tennant, AF Weisskopf, MC AF Elsner, RF Gladstone, GR Waite, JH Crary, FJ Howell, RR Johnson, RE Ford, PG Metzger, AE Hurley, KC Feigelson, ED Garmire, GP Bhardwaj, A Grodent, DC Majeed, T Tennant, AF Weisskopf, MC TI Discovery of soft X-ray emission from Io, Europa, and the Io Plasma Torus SO ASTROPHYSICAL JOURNAL LA English DT Article DE planets and satellites : individual (Io, Europa, Jupiter); X-rays : general ID CHARGE-TRANSFER; JUPITER; SPECTROMETER; TEMPERATURE; BOMBARDMENT; SATELLITES; ELECTRONS; HYDROGEN; GANYMEDE AB We report the discovery of soft (0.25-2 keV) X-ray emission from the Galilean satellites Io and Europa, probably Ganymede, and from the Io Plasma Torus (IPT). Bombardment by energetic (greater than 10 keV) H, O, and S ions from the region of the IPT seems to be the likely source of the X-ray emission from the Galilean satellites. According to our estimates, fluorescent X-ray emission excited by solar X-rays, even during flares from the active Sun, charge-exchange processes, previously invoked to explain Jupiter's X-ray aurora and cometary X-ray emission, and ion stripping by dust grains fail to account for the observed emission. On the other hand, bremsstrahlung emission of soft X-rays from nonthermal electrons in the few hundred to few thousand eV range may account for a substantial fraction of the observed X-ray flux from the IPT. C1 NASA, Dept Space Sci, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. SW Res Inst, Dept Space Sci, San Antonio, TX 78228 USA. Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48109 USA. Univ Wyoming, Dept Phys & Astron, Laramie, WY 82071 USA. Univ Virginia, Dept Engn Phys, Charlottesville, VA 22903 USA. MIT, Ctr Space Res, Cambridge, MA 02139 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA. Vikram Sarabhai Space Ctr, Space Phys Lab, Trivandrum 695022, Kerala, India. RP Elsner, RF (reprint author), NASA, Dept Space Sci, George C Marshall Space Flight Ctr, SD50, Huntsville, AL 35812 USA. OI Bhardwaj, Anil/0000-0003-1693-453X NR 33 TC 33 Z9 33 U1 0 U2 5 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 20 PY 2002 VL 572 IS 2 BP 1077 EP 1082 DI 10.1086/340434 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 560FC UT WOS:000176071200034 ER PT J AU Refregier, A Rhodes, J Groth, EJ AF Refregier, A Rhodes, J Groth, EJ TI Cosmic shear and power spectrum normalization with the Hubble Space Telescope SO ASTROPHYSICAL JOURNAL LA English DT Article DE dark matter; gravitational lensing; large-scale structure of universe; methods : data analysis ID LARGE-SCALE STRUCTURE; REDSHIFT SURVEY; GALAXIES; STATISTICS; MATTER; WFPC2 AB Weak lensing by large-scale structure provides a direct measurement of matter fluctuations in the universe. We report a measurement of this "cosmic shear" based on 271 Wide Field Planetary Camera 2 archival images from the Hubble Space Telescope Medium Deep Survey. Our measurement method and treatment of systematic effects were discussed in an earlier paper. We measure the shear variance on scales ranging from 0.'7 to 1.'4, with a detection significance greater than 3.8 sigma. This allows us to measure the normalization of the matter power spectrum to be sigma(8) = (0.94 +/- 0.10 +/- 0.14)(0.3/Omega(m))(0.44) (0.21/Gamma)(0.15), in a LambdaCDM universe. The first 1 sigma error includes statistical errors only, while the latter also includes (Gaussian) cosmic variance and the uncertainty in the galaxy redshift distribution. Our results are consistent with earlier cosmic shear measurements from the ground and from space. We compare our cosmic shear results and those from other groups to the normalization from cluster abundance and galaxy surveys. We find that the combination of four recent cosmic shear measurements are somewhat inconsistent with the recent normalization using these methods and discuss possible explanations for the discrepancy. C1 Inst Astron, Cambridge CB3 OHA, England. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Princeton Univ, Dept Phys, Princeton, NJ 08544 USA. RP Refregier, A (reprint author), Inst Astron, Madingley Rd, Cambridge CB3 OHA, England. NR 27 TC 70 Z9 71 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 20 PY 2002 VL 572 IS 2 BP L131 EP L134 DI 10.1086/341666 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 560FG UT WOS:000176071600003 ER PT J AU Barenboim, G Beacom, JF Borissov, L Kayser, B AF Barenboim, G Beacom, JF Borissov, L Kayser, B TI CPT violation and the nature of neutrinos SO PHYSICS LETTERS B LA English DT Article DE neutrino mass and mixing; double beta decay ID OSCILLATIONS AB In order to accommodate the neutrino oscillation signals from the solar, atmospheric, and LSND data, a sterile fourth neutrino is generally invoked, though the fits to the data are becoming more and more constrained. However, it has recently been shown that the data can be explained with only three neutrinos, if one invokes CPT violation to allow different masses and mixing angles for neutrinos and antineutrinos. We explore the nature of neutrinos in such CPT-violating scenarios. Majorana neutrino masses are allowed, but in general, there are no longer Majorana neutrinos in the conventional sense. However, CPT-violating models still have interesting consequences for neutrinoless double beta decay. Compared to the usual case, while the larger mass scale (from LSND) may appear, a greater degree of suppression can also occur. (C) 2002 Elsevier Science B.V. All rights reserved. C1 Fermilab Natl Accelerator Lab, Dept Theoret Phys, Batavia, IL 60510 USA. Fermilab Natl Accelerator Lab, NASA, Fermilab Astrophys Ctr, Batavia, IL 60510 USA. Columbia Univ, Dept Phys, New York, NY 10027 USA. RP Barenboim, G (reprint author), Fermilab Natl Accelerator Lab, Dept Theoret Phys, POB 500, Batavia, IL 60510 USA. OI Beacom, John/0000-0002-0005-2631 NR 31 TC 47 Z9 48 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD JUN 20 PY 2002 VL 537 IS 3-4 BP 227 EP 232 AR PII S0370-2693(02)01947-0 DI 10.1016/S0370-2693(02)01947-0 PG 6 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 568RP UT WOS:000176556900007 ER PT J AU Watson, KA Palmieri, FL Connell, JW AF Watson, KA Palmieri, FL Connell, JW TI Space environmentally stable polyimides and copolyimides derived from [2,4-bis(3-aminophenoxy)phenyl]diphenylphosphine oxide SO MACROMOLECULES LA English DT Article ID POLY(ARYLENE ETHER HETEROCYCLE)S; ATOMIC OXYGEN EXPOSURE; PHENYLPHOSPHINE OXIDE; GAMMA-RADIOLYSIS; WATER PLASMA; FILMS; PHOSPHORUS; POLYMERS AB Polyimides with a combination of proper-ties including low solar absorptivity (a) in thin films, atomic oxygen (AO), and ultraviolet (UV) radiation resistance, solubility in organic solvents in the imide form, high glass transition (T-g) temperatures, and high thermal stability have been prepared and characterized. The polymers were prepared by reacting a novel aromatic diamine, [2,4-bis(3-aminophenoxy)phenyl)diphenylphosphine oxide (2), with aromatic dianhydrides in a polar aprotic solvent. The diamine was prepared from commercially available starting materials in a two-step reaction in relatively high yield. Copoly(amide acid)s and copolyimides were prepared using 2 in combination with other commercially available aromatic diamines. The chemistry as well as physical and mechanical properties of the polymers and films will be discussed. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Connell, JW (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 26 TC 77 Z9 81 U1 3 U2 12 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD JUN 18 PY 2002 VL 35 IS 13 BP 4968 EP 4974 DI 10.1021/ma0201779 PG 7 WC Polymer Science SC Polymer Science GA 562TR UT WOS:000176215500020 ER PT J AU Poggi, MA Bottomley, LA Lillehei, PT AF Poggi, MA Bottomley, LA Lillehei, PT TI Scanning probe microscopy SO ANALYTICAL CHEMISTRY LA English DT Review ID ATOMIC-FORCE MICROSCOPY; CARBON-NANOTUBE PROBE; SELF-ASSEMBLED MONOLAYERS; FIELD OPTICAL MICROSCOPY; SINGLE DNA-MOLECULES; AFM DATA-STORAGE; ELECTROCHEMICAL MICROSCOPY; CANTILEVER ARRAY; MECHANICAL-PROPERTIES; ELECTRONIC-PROPERTIES C1 Georgia Inst Technol, Sch Chem & Biochem, Atlanta, GA 30332 USA. NASA, Langley Res Ctr, Adv Mat & Proc Branch, Hampton, VA 23681 USA. RP Bottomley, LA (reprint author), Georgia Inst Technol, Sch Chem & Biochem, Atlanta, GA 30332 USA. RI Lillehei, Peter/C-9196-2009; OI Lillehei, Peter/0000-0001-8183-9980; Bottomley, Lawrence/0000-0002-2325-9862 NR 189 TC 28 Z9 30 U1 2 U2 18 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD JUN 15 PY 2002 VL 74 IS 12 BP 2851 EP 2862 DI 10.1021/ac025695w PG 12 WC Chemistry, Analytical SC Chemistry GA 563JZ UT WOS:000176253700017 PM 12090669 ER PT J AU Cavalieri, DJ AF Cavalieri, DJ TI A link between Fram Strait sea ice export and atmospheric planetary wave phase SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID NORTH-ATLANTIC OSCILLATION; ARCTIC-OCEAN; CIRCULATION AB [1] A link is found between the variability of Fram Strait sea ice export and the phase of zonal wave 1 in SLP for the period 1958-1997. Previous studies have found that the link between ice export through Fram Strait and the NAO is inconsistent over time scales longer than the last two decades. Inconsistent and low correlations are also found between Fram Strait ice export and the AO index. The phase of zonal wave 1 explains 60%-70% of the simulated ice export variance after the removal of two anomalous phases in 1966 and 1967. Unlike the NAO and AO links, these high variances are consistent for both the first and second halves of the 40-year period. This consistency is attributed to the sensitivity of wave-1 phase to the presence of secondary low pressure systems in the Barents Sea that serve to drive Arctic sea ice southward through Fram Strait. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Cavalieri, DJ (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 14 TC 15 Z9 15 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 15 PY 2002 VL 29 IS 12 AR 1614 DI 10.1029/2002GL014684 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 610MP UT WOS:000178964100009 ER PT J AU Chu, DA Kaufman, YJ Ichoku, C Remer, LA Tanre, D Holben, BN AF Chu, DA Kaufman, YJ Ichoku, C Remer, LA Tanre, D Holben, BN TI Validation of MODIS aerosol optical depth retrieval over land SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID REFLECTANCE; INSTRUMENT; NETWORK; AERONET; SKY AB [1] Aerosol optical depths ( a) are derived operationally for the first time from the MODIS (Moderate Resolution Imaging Spectroradiometer) measurements over vegetated and partially vegetated land at 0.47 and 0.66 mum wavelengths. The extensive validation made during July - September 2000 encompasses 315 co-located tau(a) in space and time derived by MODIS and AERONET (Aerosol Robotic Network) from more than 30 AERONET sites. The lack of AERONET measurements in East Asia, India and Australia makes this validation unavailable for those regions. The MODIS aerosol retrievals, except in coastal zones, are found within the retrieval errors of Deltatau(a) = +/-0.05 +/-0.2 tau(a). The root mean square (RMS) errors are less than or equal to0.1 in the continental inland regions and up to 0.3 in the coastal regions (attributed mainly to water contaminated signals). With this validation we believe that MODIS aerosol products can be used quantitatively in many applications with caution for possible residual clouds, snow/ice, and water contamination. C1 Sci Syst & Appl Inc, Lanham, MD 20706 USA. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Uni Sci & Technol Lille, Opt Atmospher Lab, Villeneuve Dascq, France. NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. RP Sci Syst & Appl Inc, Lanham, MD 20706 USA. EM achu@climate.gsfc.nasa.gov; tanre@loa.univ-lillel.fr; brent@aeronet.gsfc.nasa.gov RI Ichoku, Charles/E-1857-2012 OI Ichoku, Charles/0000-0003-3244-4549 NR 12 TC 348 Z9 374 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 15 PY 2002 VL 29 IS 12 AR 1617 DI 10.1029/2001GL013205 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 610MP UT WOS:000178964100006 ER PT J AU Delcourt, DC Moore, TE Orsini, S Millilo, A Sauvaud, JA AF Delcourt, DC Moore, TE Orsini, S Millilo, A Sauvaud, JA TI Centrifugal acceleration of ions near Mercury SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID PLASMA SHEET; POLAR WIND; MAGNETOSPHERE; DYNAMICS; MODEL; IONOSPHERE; EVENTS AB [1] We investigate the parallel acceleration of ions inside Mercury's magnetosphere. We focus on centrifugal effects associated with the large scale plasma convection. We demonstrate that, because curvature radii of the E x B drift paths are much smaller at Mercury than at Earth, centrifugal effects are enhanced and lead to prominent parallel energization during transport from high to low latitudes. For moderate convection rates, model trajectory calculations reveal that these E x B related centrifugal effects yield energization of heavy ions sputtered from Mercury's surface (e. g., Na+) of several tens or a few hundreds of eV within minutes. This suggests that, at Mercury, material of planetary origin is rapidly raised up to plasma sheet energies. Such a situation contrasts with that prevailing at Earth where these centrifugal effects are relatively weak, yielding energization of ionosphere originating ions of at most a few tens of eV on the time scale of hours. C1 Ctr Etud Environm Terr & Planetaires, St Maur des Fosses, France. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. CNR, Ist Fis Spazio Interplanetario, I-00044 Frascati, Italy. Ctr Etud Spatiale Rayonnements, Toulouse, France. RP Delcourt, DC (reprint author), Ctr Etud Environm Terr & Planetaires, St Maur des Fosses, France. RI Moore, Thomas/D-4675-2012 OI Moore, Thomas/0000-0002-3150-1137 NR 19 TC 22 Z9 22 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 15 PY 2002 VL 29 IS 12 AR 1591 DI 10.1029/2001GL013829 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 610MP UT WOS:000178964100032 ER PT J AU Farrell, WM Fitzenreiter, RJ Kaiser, ML Goetz, K Maksimovic, M Reiner, MJ AF Farrell, WM Fitzenreiter, RJ Kaiser, ML Goetz, K Maksimovic, M Reiner, MJ TI Continuum emission and broadband electrostatic noise at the low latitude boundary layer: A diagnostic of boundary layer dynamics SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID KELVIN-HELMHOLTZ INSTABILITY; WIND SPACECRAFT; SOLITARY WAVES; BEAM INSTABILITIES; PLASMA; MAGNETOTAIL; GEOTAIL; MAGNETOPAUSE; MAGNETOSPHERE; CONVECTION AB [1] We examine the plasma and radio waves near the inner edge of the low latitude boundary layer (LLBL) during a period of time when the layer is in a "pulsed'' oscillating configuration. Previous work suggests there are numerous possible explanations for such oscillations including a Kelvin-Helmholtz instability, flux transfer events, and a boundary response to solar wind pressure oscillations. We demonstrate that the inner edge of the LLBL is indeed in motion, based upon the influence this motion has on the incident freely-propagating continuum emission. We also demonstrate that the inner boundary contains impulsive broadband events that appear, in high resolution, as a series of bipolar solitary pulses. These are the result of a kinetic electron beam instability occurring in association with the boundary fluid motion. We suggest that the large-scale fluid motion drives the kinetic instability via particle evacuation near the oscillating boundary. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Minnesota, Sch Phys & Astron, Minneapolis, MN 55455 USA. Observ Paris, Meudon, France. Catholic Univ Amer, Washington, DC 20064 USA. RP Farrell, WM (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Farrell, William/I-4865-2013 NR 29 TC 3 Z9 4 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 15 PY 2002 VL 29 IS 12 AR 1580 DI 10.1029/2000GL012799 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 610MP UT WOS:000178964100043 ER PT J AU Fueglistaler, S Luo, BP Buss, S Wernli, H Voigt, C Muller, M Neuber, R Hostetler, CA Poole, LR Flentje, H Fahey, DW Northway, MJ Peter, T AF Fueglistaler, S Luo, BP Buss, S Wernli, H Voigt, C Muller, M Neuber, R Hostetler, CA Poole, LR Flentje, H Fahey, DW Northway, MJ Peter, T TI Large NAT particle formation by mother clouds: Analysis of SOLVE/THESEO-2000 observations SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID POLAR STRATOSPHERIC CLOUDS; NITRIC-ACID TRIHYDRATE; LIDAR OBSERVATIONS; ARCTIC STRATOSPHERE; LIQUID PARTICLES; COEXISTENCE; HNO3 AB [1] During the SOLVE/THESEO-2000 Arctic stratospheric campaign in the winter 1999/2000 widespread occurrences of very large HNO3-containing particles, probably composed of nitric acid trihydrate (NAT), were observed in situ by instruments on board the ER-2 stratospheric research aircraft. These large NAT particles were found with low number densities (n approximate to 10(-4) cm(-3)) in vast regions, in air generally supersaturated with respect to NAT. Within the same campaign other instruments have performed airborne and ground-based measurements of polar stratospheric clouds (PSCs), often showing the existence of type 1a and type 1a-enh clouds. Such PSCs often occur on the mesoscale with particle number densities n greater than or similar to 10(-2) cm(-3) and are also most likely composed of NAT. We use forward trajectories for the path of NAT particles, which are advected by winds based on ECMWF analyses and sediment due to gravity, to show that high number density NAT PSCs (mother clouds) could give rise to low number density NAT particle populations several days downstream. C1 Swiss Fed Inst Technol, CH-8093 Zurich, Switzerland. Fdn Polar & Marine Res, AWI, Res Unit Potsdam, D-14473 Potsdam, Germany. NASA, Langley Res Ctr, Hampton, VA 23665 USA. DLR Oberpfaffenhofen, D-82230 Wessling, Germany. NOAA, Aeron Lab, Boulder, CO 80303 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Fueglistaler, S (reprint author), Swiss Fed Inst Technol, CH-8093 Zurich, Switzerland. RI Voigt, Christiane/G-3279-2010; Fueglistaler, Stephan/I-5803-2013; Neuber, Roland/B-4923-2014; Fahey, David/G-4499-2013 OI Neuber, Roland/0000-0001-7382-7832; Fahey, David/0000-0003-1720-0634 NR 22 TC 14 Z9 14 U1 1 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 15 PY 2002 VL 29 IS 12 AR 1610 DI 10.1029/2001GL014548 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 610MP UT WOS:000178964100013 ER PT J AU Hesse, M Kuznetsova, M Hoshino, M AF Hesse, M Kuznetsova, M Hoshino, M TI The structure of the dissipation region for component reconnection: Particle simulations SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID COLLISIONLESS MAGNETIC RECONNECTION; EARTHS MAGNETOPAUSE; FIELD; CHALLENGE; DYNAMICS; PLASMA AB [1] Results from a kinetic simulation of component reconnection are presented. Reconnection proceeds in a current sheet with 104 degrees magnetic field rotation. As a result, magnetic reconnection forms distinctively different signatures from what was found from kinetic models of anti-parallel reconnection. In particular, ion and electron flow patterns are substantially distorted, the shear magnetic field component does not exhibit a quadrupolar structure, and electron orbits in the diffusion region are substantially modified. The emphasis of the investigation is on the modifications to the diffusion region, with particular emphasis on the electron diffusion zone. Electron pressure nongyrotropies can support collisionless magnetic reconnection even when electron motion in diffusion region is strongly affected by the guide magnetic field. C1 NASA, Goddard Space Flight Ctr, Electrodynam Branch, Greenbelt, MD 20771 USA. Univ Tokyo, Tokyo, Japan. RP Hesse, M (reprint author), NASA, Goddard Space Flight Ctr, Electrodynam Branch, Greenbelt, MD 20771 USA. RI Hesse, Michael/D-2031-2012; Kuznetsova, Maria/F-6840-2012 NR 29 TC 38 Z9 39 U1 1 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 15 PY 2002 VL 29 IS 12 AR 1563 DI 10.1029/2001GL014714 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 610MP UT WOS:000178964100060 ER PT J AU Ichoku, C Chu, DA Mattoo, S Kaufman, YJ Remer, LA Tanre, D Slutsker, I Holben, BN AF Ichoku, C Chu, DA Mattoo, S Kaufman, YJ Remer, LA Tanre, D Slutsker, I Holben, BN TI A spatio-temporal approach for global validation and analysis of MODIS aerosol products SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID AERONET AB [1] With the launch of the MODIS sensor on the Terra spacecraft, new data sets of the global distribution and properties of aerosol are being retrieved, and need to be validated and analyzed. A system has been put in place to generate spatial statistics (mean, standard deviation, direction and rate of spatial variation, and spatial correlation coefficient) of the MODIS aerosol parameters over more than 100 validation sites spread around the globe. Corresponding statistics are also computed from temporal subsets of AERONET-derived aerosol data. The means and standard deviations of identical parameters from MODIS and AERONET are compared. Although, their means compare favorably, their standard deviations reveal some influence of surface effects on the MODIS aerosol retrievals over land, especially at low aerosol loading. The direction and rate of spatial variation from MODIS are used to study the spatial distribution of aerosols at various locations either individually or comparatively. This paper introduces the methodology for generating and analyzing the data sets used by the two MODIS aerosol validation papers in this issue. C1 NASA, Goddard Space Flight Ctr, Sci Syst & Appl Inc, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Univ Sci & Technol Lille, Villeneuve Dascq, France. CNRS, Opt Atmospher Lab, Villeneuve Dascq, France. NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. RP Ichoku, C (reprint author), NASA, Goddard Space Flight Ctr, Sci Syst & Appl Inc, Greenbelt, MD 20771 USA. RI Ichoku, Charles/E-1857-2012 OI Ichoku, Charles/0000-0003-3244-4549 NR 8 TC 104 Z9 105 U1 5 U2 19 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 15 PY 2002 VL 29 IS 12 AR 1616 DI 10.1029/2001GL013206 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 610MP UT WOS:000178964100007 ER PT J AU Mariotti, A Zeng, N Lau, KM AF Mariotti, A Zeng, N Lau, KM TI Euro-Mediterranean rainfall and ENSO - a seasonally varying relationship SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID NORTH-ATLANTIC OSCILLATION; NINO SOUTHERN OSCILLATION; EL-NINO; CLIMATE VARIABILITY; PRECIPITATION; TELECONNECTION; TEMPERATURES; PATTERNS AB [1] Using observational datasets and atmospheric reanalyses, we show that interannual variability of rainfall in the Euro-Mediterranean sector is significantly influenced by ENSO in a way that is seasonally varying. Spatially coherent correlation patterns are found in central and eastern Europe during winter and spring, and in western Europe and the Mediterranean region during autumn and spring. A composite analysis of ENSO events indicates that during an El Nino western Mediterranean rainfall has a 10% increase (decrease) in the autumn preceeding (spring after) the mature phase of an event, corresponding to a rainy season arriving (retreating) earlier compared to the climatology. The atmospheric reanalyses show that an anomalous atmospheric circulation and moisture transport extending from the Atlantic Ocean into the Euro-Mediterranean region accompanies the observed rainfall anomalies. Multidecadal variations characterize the ENSO Euro-Mediterranean relationship during the 20th century. C1 ENEA, Natl Agcy, Climate Sect, I-00060 Rome, Italy. Univ Maryland, Dept Meteorol, College Pk, MD 20742 USA. Univ Maryland, Ctr Earth Syst Sci, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Climate & Radiat Branch, Greenbelt, MD 20771 USA. RP Mariotti, A (reprint author), ENEA, Natl Agcy, Climate Sect, Via Anguillarese 301-SP 91,SM Galeria, I-00060 Rome, Italy. RI Zeng, Ning/A-3130-2008 OI Zeng, Ning/0000-0002-7489-7629 NR 23 TC 85 Z9 86 U1 3 U2 12 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 15 PY 2002 VL 29 IS 12 AR 1621 DI 10.1029/2001GL014248 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 610MP UT WOS:000178964100002 ER PT J AU Martins, JV Tanre, D Remer, L Kaufman, Y Mattoo, S Levy, R AF Martins, JV Tanre, D Remer, L Kaufman, Y Mattoo, S Levy, R TI MODIS Cloud screening for remote sensing of aerosols over oceans using spatial variability SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB [1] A cloud masking algorithm based on the spatial variability of reflectances at the top of the atmosphere in visible wavelengths was developed for the retrieval of aerosol properties by MODIS. It is shown that the spatial pattern of cloud reflectance as observed from space, is very different from that of aerosols. Clouds show a very high spatial variability in the scale of hundred meters to few kilometers, whereas aerosols in general are very homogeneous. The concept of spatial variability of reflectances at the top of the atmosphere is mainly applicable over the ocean where the surface background is sufficiently homogeneous for the separation between aerosols and clouds. Aerosol retrievals require a particular cloud masking approach since a conservative mask will screen out strong aerosol episodes and a less conservative mask could allow for cloud contamination that tremendously affect the retrieved aerosol optical properties (e. g. aerosol optical depth and effective radii). A detailed study on the effect of cloud contamination on aerosol retrievals is performed and parameters are established determining the threshold value for the MODIS aerosol cloud mask (3X3-STD) over the ocean. The 3X3-STD algorithm discussed in this paper is the operational cloud mask used for MODIS aerosol retrievals over the ocean. C1 Univ Maryland Baltimore Cty, JCET, Baltimore, MD 21228 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Sci & Technol Lille, Villeneuve Dascq, France. CNRS, Opt Atmospher Lab, Villeneuve Dascq, France. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Sci Syst & Appl Inc, Greenbelt, MD 20771 USA. RP Martins, JV (reprint author), Univ Maryland Baltimore Cty, JCET, Baltimore, MD 21228 USA. RI Levy, Robert/M-7764-2013 OI Levy, Robert/0000-0002-8933-5303 NR 10 TC 55 Z9 55 U1 2 U2 13 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 15 PY 2002 VL 29 IS 12 AR 1619 DI 10.1029/2001GL013252 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 610MP UT WOS:000178964100004 ER PT J AU Remer, LA Tanre, D Kaufman, YJ Ichoku, C Mattoo, S Levy, R Chu, DA Holben, B Dubovik, O Smirnov, A Martins, JV Li, RR Ahmad, Z AF Remer, LA Tanre, D Kaufman, YJ Ichoku, C Mattoo, S Levy, R Chu, DA Holben, B Dubovik, O Smirnov, A Martins, JV Li, RR Ahmad, Z TI Validation of MODIS aerosol retrieval over ocean SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SKY RADIANCE MEASUREMENTS; OPTICAL-PROPERTIES; AERONET; NETWORK; SUN AB [1] The MODerate resolution Imaging Spectroradiometer (MODIS) algorithm for determining aerosol characteristics over ocean is performing within expected accuracy. A two-month data set of MODIS retrievals co-located with observations from the AErosol RObotic NETwork (AERONET) ground-based sunphotometer network provides the necessary validation. Spectral radiation measured by MODIS (in the range 550-2100 nm) is used to retrieve the aerosol optical thickness, effective particle radius and ratio between the submicron and micron size particles. MODIS-retrieved aerosol optical thickness at 660 nm and 870 nm fall within the expected uncertainty, with the ensemble average at 660 nm differing by only 2% from the AERONET observations and having virtually no offset. Roughly seventy percent of MODIS retrievals of aerosol effective radius for optical thickness greater than 0.15 agree with AERONET retrievals to within +/-0.10 mum. C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Univ Sci & Technol Lille, Villeneuve Dascq, France. CNRS, Opt Atmospher Lab, Villeneuve Dascq, France. Sci & Data Syst Inc, Silver Spring, MD 20906 USA. NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. Sci Syst & Appl Inc, Lanham, MD USA. Univ Maryland Baltimore Cty, Baltimore, MD 21228 USA. RP Remer, LA (reprint author), NASA, Goddard Space Flight Ctr, Atmospheres Lab, Code 913, Greenbelt, MD 20771 USA. RI Dubovik, Oleg/A-8235-2009; Smirnov, Alexander/C-2121-2009; Ichoku, Charles/E-1857-2012; Levy, Robert/M-7764-2013 OI Dubovik, Oleg/0000-0003-3482-6460; Smirnov, Alexander/0000-0002-8208-1304; Ichoku, Charles/0000-0003-3244-4549; Levy, Robert/0000-0002-8933-5303 NR 10 TC 7 Z9 9 U1 2 U2 8 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 15 PY 2002 VL 29 IS 12 AR 1618 DI 10.1029/2001GL013204 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 610MP UT WOS:000178964100005 ER PT J AU Rignot, E Hallet, B Fountain, A AF Rignot, E Hallet, B Fountain, A TI Rock glacier surface motion in Beacon Valley, Antarctica, from synthetic-aperture radar interferometry SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SOUTHERN-VICTORIA-LAND; SAR INTERFEROMETRY; DRY-VALLEYS; ICE; ALPS AB [1] We present radar interferograms of rock glaciers in the Beacon Valley sector of the McMurdo Dry Valleys, in East Antarctica, as part of a comprehensive study of surface processes in the area. Due to the relative absence of net precipitation (snow) in this region and the stability of the surface, the rock glaciers maintain excellent coherence of the radar returns over several years. As a result, we obtain a spatially continuous surface velocity field with a precision of fractions of a millimeter per year. On distinct rock glaciers entering Beacon Valley, we find coherent velocity patterns, with peak velocities approaching 40 mm per year. The ice supply from these rock glaciers nourishes the central portion of Beacon Valley, where velocities are found to be vanishingly small, and partly compensates for mass losses induced by sublimation. This analysis is consistent with the tantalizing notion that Beacon Valley ice is the oldest on Earth. C1 CALTECH, Jet Prop Lab, Radar Sci & Engn Sect, Pasadena, CA 91109 USA. Univ Washington, Quaternary Res Ctr, Seattle, WA 98195 USA. Portland State Univ, Dept Geol, Portland, OR 97207 USA. RP Rignot, E (reprint author), CALTECH, Jet Prop Lab, Radar Sci & Engn Sect, MS 300-235,4800 Grove Dr, Pasadena, CA 91109 USA. EM eric@adelie.jpl.nasa.gov; hallet@u.washington.edu; andrew@pdx.edu RI Rignot, Eric/A-4560-2014 OI Rignot, Eric/0000-0002-3366-0481 NR 22 TC 21 Z9 21 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 JUN 15 PY 2002 VL 29 IS 12 AR 1607 DI 10.1029/2001GL013494 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 610MP UT WOS:000178964100016 ER PT J AU Cruden, BA Gleason, KK Sawin, HH AF Cruden, BA Gleason, KK Sawin, HH TI Optical emission spectroscopy of pulsed hexalfuoropropylene oxide and tetrafluoroethylene plasmas SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID HEXAFLUOROPROPYLENE OXIDE; FLUOROCARBON PLASMAS; ETCHING PROCESSES; ELECTRON; DIAGNOSTICS; ACTINOMETRY; TEMPERATURE; DISCHARGES; DENSITY; SPECTRA AB The optical emission spectra of tetrafluoroethylene (TFE) and hexafluoropropylene oxide (HFPO) have been examined for chemistry and electron distribution transients as a function of plasma pulsing, under depositing conditions (1 torr). The major identifiable peaks in these plasmas are attributable to CF2 and CF. Other expected species, including CF3, atomic F and atomic C are not observed. HFPO plasmas show significant emission from CO and O. Comparison of CF2 emission transients to absolute absorption measurements show that the continuum emission surrounding CF2 is not attributable to CF2+ emission, as has been previously proposed, but is likely rovibrational overlap. Argon emission in TFE shows a relatively slow transient toward steady state (similar to20 ms), implying slower chemistry transients, such as attachment, control the electron transient in pulsed TFE plasmas. In HFPO plasmas, CO and O actinometry are applied. CO emission trends suggest that CO is actually produced during the plasma off times, and is here attributed to etching reactions in the film. The rotational structure of CO is also examined and fit to estimate plasma rotational temperature, giving temperature transients on the order of similar to20 ms. (C) 2002 American Institute of Physics. C1 MIT, Dept Chem Engn, Cambridge, MA 02139 USA. RP Cruden, BA (reprint author), Eloret Corp, NASA, Ames Res Ctr, Sunnyvale, CA 94087 USA. RI Gleason, Karen/G-1471-2013 OI Gleason, Karen/0000-0001-6127-1056 NR 35 TC 9 Z9 9 U1 0 U2 10 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 15 PY 2002 VL 91 IS 12 BP 9547 EP 9555 DI 10.1063/1.1471386 PG 9 WC Physics, Applied SC Physics GA 557JJ UT WOS:000175905200013 ER PT J AU Tucker, DS Nettles, AT Cagle, H AF Tucker, DS Nettles, AT Cagle, H TI Dynamic fatigue of a titanium silicate glass SO JOURNAL OF MATERIALS SCIENCE LETTERS LA English DT Article ID LIFETIME PREDICTIONS C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Tucker, DS (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 13 TC 2 Z9 2 U1 1 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0261-8028 J9 J MATER SCI LETT JI J. Mater. Sci. Lett. PD JUN 15 PY 2002 VL 21 IS 12 BP 911 EP 913 DI 10.1023/A:1016005218976 PG 3 WC Materials Science, Multidisciplinary SC Materials Science GA 567BD UT WOS:000176462000003 ER PT J AU Steinacker, J Hackert, R Steinacker, A Bacmann, A AF Steinacker, J Hackert, R Steinacker, A Bacmann, A TI The influence of numerical diffusion on the solution of the radiative transfer equations SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID AXISYMMETRICAL DUST CLOUDS; ACTIVE GALACTIC NUCLEI; INFRARED-SPECTRA; DISKS; MODELS; TORI AB We investigate the explicit numerical solution strategies of multi-dimensional radiative transfer equations which are commonly used, e.g., to determine the radiation emerging from astrophysical objects surrounded by absorbing and scattering, matter. For explicit grid solvers, we identify numerical diffusion as a severe source of error in first-order discretization schemes, underestimated in former work about radiative transfer. Using the simple example of a beam propagating through vacuum, we illustrate the influence of the diffusion on the solution and discuss various techniques to reduce it. In view of the large required storage for implicit solvers, we propose to use second-order explicit grid techniques to solve 3D radiative transfer problems. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 Observ Jena, Inst Astrophys, D-07745 Jena, Germany. Univ Jena, Observ Jena, D-07745 Jena, Germany. NASA, Ames Res Ctr, Stanford, CA 94305 USA. RP Steinacker, J (reprint author), Observ Jena, Inst Astrophys, Schillergrasschen 2-3, D-07745 Jena, Germany. NR 20 TC 9 Z9 9 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD JUN 15 PY 2002 VL 73 IS 6 BP 557 EP 569 AR PII S0022-4073(01)00179-0 DI 10.1016/S0022-4073(01)00179-0 PG 13 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 542AM UT WOS:000175020800003 ER PT J AU Devi, VM Benner, DC Smith, MAH Rinsland, CP Brown, LR AF Devi, VM Benner, DC Smith, MAH Rinsland, CP Brown, LR TI Multispectrum analysis of self- and nitrogen-broadening, pressure shifting and line mixing in the nu(3) parallel band of (CH3D)-C-12 SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article DE methane; monodeuterated methane; infrared spectra; Fourier transform infrared (FTIR) spectroscopy; spectral line shape ID DIODE-LASER MEASUREMENTS; 6-10 MU-M; INFRARED OBSERVATIONS; FITTING TECHNIQUE; CH3D; COEFFICIENTS; TEMPERATURES; INTENSITIES; ABSORPTION; SPECTRUM AB Lorentz self- and nitrogen-broadening coefficients as well as self- and nitrogen-p res sure induced shift coefficients were measured at room temperature for more than 440 transitions in the P-Q, (Q)Q and R-Q branches of the (v3)(Al) parallel band of (CH3D)-C-12. The simultaneous multispectrum nonlinear least-squares fitting analysis was performed in the 1140-1440 cm(-1) region using 14 spectra of room temperature gas recorded with the McMath-Pierce Fourier transform spectrometer (0.005 cm(-1) unapodized resolution) of the National Solar Observatory (NSO) on Kitt Peak. The measured self-broadening coefficients varied from about 0.025 cm-1 atm(-1) at 296 K for high J, K transitions to about 0.09 cm(-1) atm(-1) at 296 K for low J, K transitions. In the case of nitrogen broadening these values ranged from about 0.023 to 0.073 cm(-1) atm(-1) at 296 K. The majority (> 90%) of the self-pressure induced shift coefficients as well as nitrogen-pressure-induced shift coefficients was negative with values varying between approximately 0 and -0.012 cm-1 atm(-1). However, similar to air-induced pressure-shift coefficients determined in an earlier study, the measured self- and nitrogen-induced pressure-shift coefficients were positive for the R-Q-branch transitions with J" = K", varying from 0 to about +0.009 cm(-1) atm(-1). Weak line mixing effects were observed in several high-J lines with K" = 3 splitting and approximate values for the off-diagonal relaxation matrix-element coefficients were determined for a few A(1)A(2) (A(+)A(-)) split components. Comparisons are made between the measured self- and nitrogen-broadening and shift coefficients, and the results are also compared with measurements in other bands. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 Coll William & Mary, Dept Phys, Williamsburg, VA 23187 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Devi, VM (reprint author), Coll William & Mary, Dept Phys, Box 8795, Williamsburg, VA 23187 USA. NR 29 TC 17 Z9 18 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD JUN 15 PY 2002 VL 73 IS 6 BP 603 EP 640 AR PII S0022-4073(01)00182-0 DI 10.1016/S0022-4073(01)00182-0 PG 38 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 542AM UT WOS:000175020800006 ER PT J AU Baker, J Campanelli, M Lousto, CO Takahashi, R AF Baker, J Campanelli, M Lousto, CO Takahashi, R TI Modeling gravitational radiation from coalescing binary black holes SO PHYSICAL REVIEW D LA English DT Article ID INITIAL DATA; COMPACT BINARIES; PERTURBATIVE EVOLUTION; WAVE-FORMS; COLLISIONS; EQUATIONS; COALESCENCES; RELATIVITY; TEMPLATES; DYNAMICS AB With the goal of bringing theory, particularly numerical relativity, to bear on an astrophysical problem of critical interest to gravitational wave observers we introduce a model for coalescence radiation from binary black hole systems. We build our model using the Lazarus approach, a technique that bridges far and close limit approaches with full numerical relativity to solve Einstein equations applied in the truly nonlinear dynamical regime. We specifically study the post-orbital radiation from a system of equal-mass non-spinning black holes, deriving waveforms which indicate strongly circularly polarized radiation of roughly 3% of the system's total energy and 12% of its total angular momentum in just a few cycles. To support this result we first establish the reliability of the late-time part of our model, including the numerical relativity and close-limit components, with a thorough study of waveforms from a sequence of black hole configurations that varies from previously treated head-on collisions to a representative target for "ISCO" data corresponding to the end of the inspiral period. We then complete our model with a simple treatment for the early part of the spacetime based on a standard family of initial data for binary black holes in circular orbit. A detailed analysis shows strong robustness in the results as the initial separation of the black holes is increased from 5.0 to 7.8M supporting our waveforms as a suitable basic description of the astrophysical radiation from this system. Finally, a simple fitting of the plunge waveforms is introduced as a first attempt to facilitate the task of analyzing data from gravitational wave detectors. C1 NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Texas, Dept Phys & Astron, Brownsville, TX 78520 USA. Consejo Nacl Invest Cient & Tecn, Inst Astron & Fis Espacio, RA-1033 Buenos Aires, DF, Argentina. Theoret Astrophys Ctr, DK-2100 Copenhagen O, Denmark. RP Baker, J (reprint author), NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. OI Lousto, Carlos/0000-0002-6400-9640 NR 44 TC 118 Z9 118 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD JUN 15 PY 2002 VL 65 IS 12 AR 124012 DI 10.1103/PhysRevD.65.124012 PG 23 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 572JW UT WOS:000176771700043 ER PT J AU Cadez, I Greenwood, JB Chutjian, A Mawhorter, RJ Smith, SJ Niimura, M AF Cadez, I Greenwood, JB Chutjian, A Mawhorter, RJ Smith, SJ Niimura, M TI Absolute cross sections for charge-exchange in He-3(2+) and H+ impact on CO SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID ELECTRON-CAPTURE; HE2+ IONS; COLLISIONS; MOLECULES; IONIZATION; SINGLE; PROTONS; HE-2+; GASES; HE+ AB We report measured absolute single and double charge-exchange cross sections for He-3(2+) on CO at ion impact energies between 1 and 14 keV (velocities between 254 and 949 km s(-1)). A retarding-field method is used for charge-state analysis of the ion beam after traversing the target gas cell. Cross sections are determined from absolute measurements of current ratios and the CO target gas pressure. For testing the experimental technique, proton-electron capture cross sections are measured at energies between 2.5 and 7 keV. The measured He2+ and H+ cross sections are compared to available data. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Jozef Stefan Inst, SI-1000 Ljubljana, Slovenia. Queens Univ Belfast, Dept Phys, Belfast BT7 1NN, Antrim, North Ireland. Pomona Coll, Dept Phys & Astron, Claremont, CA 91711 USA. RP Cadez, I (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Greenwood, Jason/L-4799-2014 NR 23 TC 11 Z9 11 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-4075 J9 J PHYS B-AT MOL OPT JI J. Phys. B-At. Mol. Opt. Phys. PD JUN 14 PY 2002 VL 35 IS 11 BP 2515 EP 2524 AR PII S0953-4075(02)31917-5 DI 10.1088/0953-4075/35/11/310 PG 10 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 569PR UT WOS:000176611500013 ER PT J AU Hazeltine, E Ivry, RB AF Hazeltine, E Ivry, RB TI Neuroscience - Can we teach the cerebelum new tricks? SO SCIENCE LA English DT Editorial Material ID LESIONS C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Calif Berkeley, Dept Psychol, Berkeley, CA 94720 USA. RP Hazeltine, E (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM ehazeltine@mail.arc.nasa.gov OI Hazeltine, Richard/0000-0002-0893-5789 NR 14 TC 9 Z9 10 U1 1 U2 2 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD JUN 14 PY 2002 VL 296 IS 5575 BP 1979 EP 1980 DI 10.1126/science.1073926 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 563UD UT WOS:000176273300037 PM 12065822 ER PT J AU Rignot, E Jacobs, SS AF Rignot, E Jacobs, SS TI Rapid bottom melting widespread near Antarctic ice sheet grounding lines SO SCIENCE LA English DT Article ID RADAR INTERFEROMETRY; SHELF; GLACIER; CIRCULATION; DISCHARGE; GREENLAND; BENEATH; ISLAND; OCEAN AB As continental ice from Antarctica reaches the grounding tine and begins to float, its underside melts into the ocean. Results obtained with satellite radar interferometry reveal that bottom melt rates experienced by large outlet glaciers near their grounding lines are far higher than generally assumed. The melting rate is positively correlated with thermal forcing, increasing by 1 meter per year for each 0.1degreesC rise in ocean temperature. Where deep water has direct access to grounding lines, glaciers and ice shelves are vulnerable to ongoing increases in ocean temperature. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Columbia Univ, Lamont Doherty Earth Observ, Palisades, NY 10964 USA. RP Rignot, E (reprint author), CALTECH, Jet Prop Lab, MAil Stop 300-235, Pasadena, CA 91109 USA. EM eric@adelie.jpl.nasa.gov; sjacobs@ldeo.columbia.edu RI Rignot, Eric/A-4560-2014 OI Rignot, Eric/0000-0002-3366-0481 NR 40 TC 273 Z9 281 U1 4 U2 41 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD JUN 14 PY 2002 VL 296 IS 5575 BP 2020 EP 2023 DI 10.1126/science.1070942 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 563UD UT WOS:000176273300051 PM 12065835 ER PT J AU Bellwied, R Bennett, MJ Bernardo, V Caines, H Christie, W Costa, S Crawford, HJ Cronqvist, M Debbe, R Dinnwiddie, R Engelage, J Flores, I Fuzesy, R Greiner, L Hallman, T Hoffmann, G Huang, HZ Jensen, P Judd, EG Kainz, K Kaplan, M Kelly, S Linstrom, PJ Llope, WJ LoCurto, G Longacre, R Milosevich, Z Mitchell, JT Mitchell, JW Mogavero, E Mutchler, G Paganis, S Platner, E Potenza, R Rotondo, F Russ, D Sakrejda, I Saulys, A Schambach, J Sheen, J Smirnoff, N Stokeley, C Tang, J Trattner, AL Trentalange, S Visser, G Whitfield, JP Witharm, F Witharm, R Wright, M AF Bellwied, R Bennett, MJ Bernardo, V Caines, H Christie, W Costa, S Crawford, HJ Cronqvist, M Debbe, R Dinnwiddie, R Engelage, J Flores, I Fuzesy, R Greiner, L Hallman, T Hoffmann, G Huang, HZ Jensen, P Judd, EG Kainz, K Kaplan, M Kelly, S Linstrom, PJ Llope, WJ LoCurto, G Longacre, R Milosevich, Z Mitchell, JT Mitchell, JW Mogavero, E Mutchler, G Paganis, S Platner, E Potenza, R Rotondo, F Russ, D Sakrejda, I Saulys, A Schambach, J Sheen, J Smirnoff, N Stokeley, C Tang, J Trattner, AL Trentalange, S Visser, G Whitfield, JP Witharm, F Witharm, R Wright, M TI Distributed drift chamber design for rare particle detection in relativistic heavy ion collisions SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE drift chamber; relativistic heavy ions; rare particle AB This report describes a multi plane drift chamber that was designed and constructed to function as a topological detector for the BNL AGS E896 rare particle experiment. The chamber was optimized for good spatial resolution, two track separation, and a high uniform efficiency while operating in a 1.6 T magnetic field and subjected to long term exposure from a 11.6 GeV/nucleon beam of 10(6) Au ions per second. (C) 2001 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Space Sci Labs, Berkeley, CA 94720 USA. Wayne State Univ, Detroit, MI 48201 USA. Yale Univ, New Haven, CT 06520 USA. Ohio State Univ, Columbus, OH 43210 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. Univ Catania, I-95129 Catania, Italy. INFN, Sez Catania, I-95129 Catania, Italy. Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Univ Texas, Austin, TX 78712 USA. Univ Calif Los Angeles, Los Angeles, CA 90095 USA. Rice Univ, Houston, TX 77251 USA. Carnegie Mellon Univ, Pittsburgh, PA 15213 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Engelage, J (reprint author), Univ Calif Berkeley, Space Sci Labs, Berkeley, CA 94720 USA. OI PAGANIS, STATHES/0000-0002-1950-8993 NR 16 TC 0 Z9 0 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUN 11 PY 2002 VL 485 IS 3 BP 371 EP 384 AR PII S0168-9002(01)02136-2 DI 10.1016/S0168-9002(01)02136-2 PG 14 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 569BZ UT WOS:000176581300014 ER PT J AU Chiang, J AF Chiang, J TI An X-ray reprocessing model of disk thermal emission in type 1 Seyfert galaxies SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : individual (NGC 3516, NGC 7469); galaxies : Seyfert; X-rays : galaxies ID ACTIVE GALACTIC NUCLEI; BROAD-LINE REGION; ADVECTION-DOMINATED ACCRETION; NON-LTE MODELS; ULTRAVIOLET-SPECTRUM; BLACK-HOLE; THEORETICAL SPECTRA; NGC-7469; CONTINUUM; RADIATION AB Using a geometry consisting of a hot central Comptonizing plasma surrounded by a thin accretion disk, we model the optical through hard X-ray spectral energy distributions of the type 1 Seyfert galaxies NGC 3516 and NGC 7469. As in the model proposed by Poutanen, Krolik, & Ryde for the X-ray binary Cyg X-1 and later applied to Seyfert galaxies by Zdziarski, Lubinski, & Smith, feedback between the radiation reprocessed by the disk and the thermal Comptonization emission from the hot central plasma plays a pivotal role in determining the X-ray spectrum and, as we show, the optical and ultraviolet spectra as well. Seemingly uncorrelated optical/UV and X-ray light curves, similar to those that have been observed from these objects can, in principle, be explained by variations in the size, shape, and temperature of the Comptonizing plasma. Furthermore, by positing a disk mass accretion rate that satisfies a condition for global energy balance between the thermal Comptonization luminosity and the power available from accretion, one can predict the spectral properties of the heretofore poorly measured hard X-ray continuum above 50 keV in type 1 Seyfert galaxies. Conversely, forthcoming measurements of the hard X-ray continuum by more sensitive hard X-ray and soft gamma-ray telescopes, such as those aboard the International Gamma-Ray Astrophysics Laboratory, in conjunction with simultaneous optical, UV, and soft X-ray monitoring, will allow the mass accretion rates to be directly constrained for these sources in the context of this model. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland, Joint Ctr Astrophys, Dept Phys, Baltimore, MD 21250 USA. RP Chiang, J (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. NR 41 TC 25 Z9 26 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 10 PY 2002 VL 572 IS 1 BP 79 EP 93 DI 10.1086/340193 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 559BQ UT WOS:000176005100008 ER PT J AU Feigelson, ED Garmire, GP Pravdo, SH AF Feigelson, ED Garmire, GP Pravdo, SH TI Magnetic flaring in the pre main-sequence sun and implications for the early solar system SO ASTROPHYSICAL JOURNAL LA English DT Review DE meteors, meteoroids; solar system : formation; stars : pre main-sequence; Sun : activity; X-rays : stars ID T-TAURI STARS; YOUNG STELLAR OBJECTS; ORION-NEBULA CLUSTER; POLARIZED RADIO-EMISSION; GIANT BRANCH STARS; X-RAY-EMISSION; ACCRETION DISKS; COSMIC-RAYS; EXTINCT RADIOACTIVITIES; MOLECULAR CLOUDS AB To address the role of energetic processes in the solar nebula, we provide a detailed characterization of magnetic flaring in stellar analogs of the pre-main-sequence Sun based on two 0.5 day observations of the Orion Nebula cluster obtained with the Chandra X-Ray Observatory. The sample consists of 43 stars with masses between 0.7 and 1.4 M-. and ages from less than 0.3 to similar or equal to10 Myr. We find that the X-ray luminosities measured in the 0.5-8 keV band are strongly elevated over main-sequence levels with an average [log L-x] = 30.3 ergs s(-1) and [log Lx/ L-*] = 3.9. The X-ray emission is strongly variable within our exposures in nearly all solar analogs; about 30 flares with 29.0 ergs s(-1) < log L-x (peak) < 31.5 ergs s(-1) on time-scales from 0.5 to more than 12 hr are seen during the Chandra observations. Analogs of the less than or equal to1 Myr old pre-main-sequence Sun exhibited X-ray flares that are 10(1.5) times more powerful and 10(2.5) times more frequent than the most powerful flares seen on the contemporary Sun. Radio observations indicate that acceleration of particles to relativistic energies is efficient in young stellar flares. Extrapolating the solar relationship between X-ray luminosity and proton fluence, we infer that the young Sun exhibited a 10(5)-fold enhancement in energetic protons compared to contemporary levels. Unless the are geometries are unfavorable, this inferred proton flux on the disk is sufficient to produce the observed meteoritic abundances of several important short-lived radioactive isotopes. Our study thus strengthens the astronomical foundation for local proton spallation models of isotopic anomalies in carbonaceous chondritic meteorites. The radiation, particles, and shocks produced by the magnetic reconnection flares seen with Chandra may also have flash-melted meteoritic chondrules and produce excess Ne-21 seen in meteoritic grains. C1 Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Feigelson, ED (reprint author), Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA. NR 110 TC 114 Z9 114 U1 0 U2 7 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 10 PY 2002 VL 572 IS 1 BP 335 EP 349 DI 10.1086/340340 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 559BQ UT WOS:000176005100029 ER PT J AU Proga, D Kallman, TR Drew, JE Hartley, LE AF Proga, D Kallman, TR Drew, JE Hartley, LE TI Resonance line profile calculations based on hydrodynamical models of cataclysmic variable winds SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; methods : numerical; novae, cataclysmic variables; stars : winds, outflows ID RADIATION-DRIVEN WINDS; ACCRETION DISK WINDS; HIGH-VELOCITY WINDS; UX URSAE-MAJORIS; DWARF NOVA; SPECTRUM SYNTHESIS; IUE OBSERVATIONS; EMISSION-LINES; V347 PUPPIS; IX-VELORUM AB We describe a method of calculating synthetic line profiles using a generalized version of the Sobolev approximation. We apply this method to calculate line profiles predicted by the models of two-dimensional line-driven winds from luminous disks due to Proga, Stone, & Drew. We describe the main properties of the model line profiles and compare them with recent Hubble Space Telescope observations of the cataclysmic variable IX Vel. The model wind consists of a dense, slow outflow that is bounded on the polar side by a high-velocity stream. We find that these two wind components produce distinct spectral features. The fast stream produces profiles that show features consistent with observations. These include the appearance of the classical P Cygni shape for a range of inclinations, the location of the maximum depth of the absorption component at velocities less than the terminal velocity, and the transition from net absorption to net emission with increasing inclination. However, the model profiles have too little absorption or emission equivalent width compared to observed profiles. This quantitative difference between our models and observations is not a surprise because the line-driven wind models predict a mass-loss rate, mostly due to the fast stream, that is lower than the rate required by the observations. We note that the model profiles exhibit a double-humped structure near the line center that is not echoed in observations. We identify this structure with a nonnegligible red-shifted absorption that is formed in the slow component of the wind where the rotational velocity dominates over expansion velocity. We conclude that the next generation of disk wind models, developed for application to cataclysmic variables, needs to yield stronger wind driving out to larger disk radii than do the present models. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Univ London Imperial Coll Sci Technol & Med, Blackett Lab, London SW7 2BZ, England. RP Proga, D (reprint author), Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. OI Drew, Janet/0000-0003-1192-7082 NR 50 TC 24 Z9 24 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 10 PY 2002 VL 572 IS 1 BP 382 EP 391 DI 10.1086/340339 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 559BQ UT WOS:000176005100032 ER PT J AU Lee, J Gary, DE Qiu, J Gallagher, PT AF Lee, J Gary, DE Qiu, J Gallagher, PT TI Electron transport during the 1999 august 20 flare inferred from microwave and hard X-ray observations SO ASTROPHYSICAL JOURNAL LA English DT Article DE acceleration of particles; radiation mechanisms : nonthermal; Sun : corona; Sun : flares; Sun : radio radiation; Sun : X-rays, gamma rays ID TRAP-PRECIPITATING ELECTRONS; SOLAR-FLARES; ENERGETIC ELECTRONS; MAGNETIC RECONNECTION; THERMAL ELECTRONS; BURSTS; DECONVOLUTION; INJECTION; YOHKOH; LOOP AB We discuss injection and transport of high-energy electrons during a GOES X-ray class M9.8 flare observed in microwaves with the Owens Valley Solar Array (OVSA) and in hard X-rays (HXRs) with the hard X-ray telescope (HXT) on board Yohkoh. Observed at 1 s timescales or better in both wavelength regimes, the event shows (1) a large difference in scale between the microwave source and the HXR source; (2) an unusually hard HXR spectrum ( maximum spectral index similar to-1.6), followed by rapid spectral softening; and (3) a microwave light curve containing both impulsive peaks (3 s rise time) simultaneous with those of the HXRs and a long, extended tail with a uniform decay rate (2.3 minutes). We analyze the observations within the framework of the electron trap-and-precipitation model, allowing a time-dependent injection energy spectrum. Assuming thick-target bremsstrahlung for the HXRs, we infer the electron injection function in the form Q(E, t)similar to(E/E-0)(-delta(t)), where the timescale for delta(t) to change by unity is similar to7 s. This injection function can account for the characteristics of the impulsive part of the microwave burst by considering the bulk of the electrons to be directly precipitating without trapping. The same injection function also accounts for the gradual part of the microwave emission by convolving the injection function with a kernel representing the trapping process, which at late times gives N(E, t)similar toe(vt)(E/E-0)(-b). We require bsimilar to1.4 and vsimilar to6x10(-3)beta s(-1), where betais the electron speed divided by the speed of light. Therefore, the derived form of the precipitation rate itself indicates strong pitch-angle diffusion, but the slow decay of the microwave radiation requires a small loss cone (similar to4degrees) and a low ambient density in the coronal trap. Also, the numbers of electrons needed to account for the two components of the microwave emission differ by an order of magnitude. We estimate that the greater than or equal to100 keV number of the directly precipitating electrons is similar to10(33), while the trapped population requires similar to10(32) electrons. This leads us to a model of two interacting loops, the larger of which serves as an efficient trap while the smaller provides the impulsive source. These characteristics are consistent with the spatially resolved observations. C1 New Jersey Inst Technol, Dept Phys, Newark, NJ 07102 USA. NASA, Emergent Technol Serv Inc, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Lee, J (reprint author), New Jersey Inst Technol, Dept Phys, 161 Warren St, Newark, NJ 07102 USA. RI Gallagher, Peter/C-7717-2011; OI Gallagher, Peter/0000-0001-9745-0400; Gary, Dale/0000-0003-2520-8396 NR 44 TC 15 Z9 15 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 10 PY 2002 VL 572 IS 1 BP 609 EP 625 DI 10.1086/340311 PN 1 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 559BQ UT WOS:000176005100049 ER PT J AU Rubinstein, R Zhou, Y AF Rubinstein, R Zhou, Y TI Turbulent time correlations and generation of acoustic waves by stellar or solar turbulent convection SO ASTROPHYSICAL JOURNAL LA English DT Article DE convection; hydrodynamics; Sun : atmospheric motions; turbulence; waves ID CORONAL HEATING MECHANISMS; LATE-TYPE STARS; ISOTROPIC TURBULENCE; SOUND GENERATION; NOISE AB This paper considers the question of whether Eulerian or Lagrangian time correlations should be used to evaluate sound radiation by turbulent convection. Whereas previous analyses have either explicitly or implicitly used Lagrangian correlations, this paper argues in favor of Eulerian correlations. The physics of turbulent time correlations is briefly reviewed, and the implications of using Eulerian instead of Lagrangian correlations in sound-radiation calculations are discussed. The assumption made about time correlations alters the frequency distribution of the radiated sound; assuming Eulerian time correlations results in a more shallow acoustic power spectrum and consequently greater relative weighting of higher frequencies. The consequences of assuming Bolgiano scaling of buoyancy-generated turbulence are also discussed. C1 NASA, Computat Modeling & Simulat Branch, Langley Res Ctr, Hampton, VA 23681 USA. Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Rubinstein, R (reprint author), NASA, Computat Modeling & Simulat Branch, Langley Res Ctr, Hampton, VA 23681 USA. NR 34 TC 6 Z9 6 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 10 PY 2002 VL 572 IS 1 BP 674 EP 678 DI 10.1086/340223 PN 1 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 559BQ UT WOS:000176005100053 ER PT J AU Sekanina, Z Jehin, E Boehnhardt, H Bonfils, X Schuetz, O Thomas, D AF Sekanina, Z Jehin, E Boehnhardt, H Bonfils, X Schuetz, O Thomas, D TI Recurring outbursts and nuclear fragmentation of comet C/2001 A2 (LINEAR) SO ASTROPHYSICAL JOURNAL LA English DT Article DE comets : general; comets : individual (C/2001 A2); methods : data analysis ID SPLIT AB Analysis of the visual light curve and fragmentation sequence of comet C/2001 A2 (LINEAR) shows a strong temporal correlation between the onset of outbursts and separation of companion nuclei. This scenario conforms to Sekanina's conceptual model for the release of sizable fragments of an inert dust mantle from the nucleus surface: an outburst is triggered as some of the mass rapidly disintegrates into ne dust. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. European So Observ, Santiago 19, Chile. Univ Sternwarte Munchen, D-41679 Munich, Germany. RP Sekanina, Z (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. OI Bonfils, Xavier/0000-0001-9003-8894 NR 28 TC 22 Z9 22 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 10 PY 2002 VL 572 IS 1 BP 679 EP 684 DI 10.1086/340284 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 559BQ UT WOS:000176005100054 ER PT J AU Barsony, M Greene, TP Blake, GA AF Barsony, M Greene, TP Blake, GA TI A tidally interacting disk in the young triple system WL 20? SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : close; circumstellar matter; stars : formation; stars : individual (WL 20); stars : pre-main-sequence ID OPHIUCHI CLOUD CORE; EVOLUTIONARY STATUS; STELLAR OBJECTS; STAR-FORMATION; CLUSTER AB We present high-resolution lambda=2.7 mm imaging of the close triple pre-main-sequence system WL 20. Compact dust emission with integrated flux density of 12.9+/-1.3 mJy is associated with two components of the triple system, WL 20W and WL 20S. No emission above a 3 sigma level of 3.9 mJy is detected toward the third component, WL 20E, which lies 3".17 (400 AU) due east in projection from its neighbors. A possibly warped structure of similar to0.1 M-circle dot and less than or equal to3".2 extent encompasses WL 20W and WL 20S, which have a projected separation of 2".25 (similar to280 AU) along a north-south axis. This structure is most likely a tidally disrupted disk surrounding WL 20S. New near-infrared spectra of the individual components show a remarkable similarity between the two T Tauri stars of the system: WL 20E has a K7 spectral type (T-eff=4040 K) with r(K)=0.2 and WL 20W has an M0 spectral type (T-eff=3800 K) with r(K)=0.2. The spectrum of WL 20S is consistent with that of a source intrinsically similar to WL 20W, with r(K)<0.9, but seen through an A(V)=25 in addition to the to A(V)=16.3 to the system as a whole. Taken together, these millimeter and infrared data help explain the peculiar nature of the infrared companion, WL 20S, as resulting from a large enhancement in its dusty, circumstellar environment in relation to its companions. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. RP Barsony, M (reprint author), Space Sci Inst, 3100 Marine St,Suite A353, Boulder, CO 80303 USA. NR 16 TC 3 Z9 3 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 10 PY 2002 VL 572 IS 1 BP L75 EP L78 DI 10.1086/341553 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 559BW UT WOS:000176005600016 ER PT J AU Bloom, JS Kulkarni, SR Price, PA Reichart, D Galama, TJ Schmidt, BP Frail, DA Berger, E McCarthy, PJ Chevalier, RA Wheeler, JC Halpern, JP Fox, DW Djorgovski, SG Harrison, FA Sari, R Axelrod, TS Kimble, RA Holtzman, J Hurley, K Frontera, F Piro, L Costa, E AF Bloom, JS Kulkarni, SR Price, PA Reichart, D Galama, TJ Schmidt, BP Frail, DA Berger, E McCarthy, PJ Chevalier, RA Wheeler, JC Halpern, JP Fox, DW Djorgovski, SG Harrison, FA Sari, R Axelrod, TS Kimble, RA Holtzman, J Hurley, K Frontera, F Piro, L Costa, E TI Detection of a supernova signature associated with GRB 011121 SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts; supernovae : general; supernovae : individual (SN 1998bw) ID GAMMA-RAY BURSTS; 25 APRIL 1998; OPTICAL AFTERGLOW; IA SUPERNOVAE; DUST ECHOES; LIGHT-CURVE; ENERGY; JET; CALIBRATION; GRB-990712 AB Using observations from an extensive monitoring campaign with the Hubble Space Telescope, we present the detection of an intermediate-time flux excess that is redder in color relative to the afterglow of GRB 011121, currently distinguished as the gamma-ray burst with the lowest known redshift. The red "bump," which exhibits a spectral rollover at similar to7200 Angstrom, is well described by a redshifted Type Ic supernova that occurred approximately at the same time as the gamma-ray burst event. The inferred luminosity is about half that of the bright supernova SN 1998bw. These results serve as compelling evidence for a massive star origin of long-duration gamma-ray bursts. Models that posit a supernova explosion weeks to months preceding the gamma-ray burst event are excluded by these observations. Finally, we discuss the relationship between spherical core-collapse supernovae and gamma-ray bursts. C1 CALTECH, Div Phys Math & Astron, Pasadena, CA 91125 USA. Mt Stromlo & Siding Spring Observ, Res Sch Astron & Astrophys, Canberra, ACT 2611, Australia. Natl Radio Astron Observ, Socorro, NM 87801 USA. Carnegie Observ, Pasadena, CA 91101 USA. Univ Virginia, Dept Astron, Charlottesville, VA 22903 USA. Univ Texas, Dept Astron, Austin, TX 78712 USA. Columbia Univ, Columbia Astrophys Lab, New York, NY 10027 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. New Mexico State Univ, Dept Astron, Las Cruces, NM 88003 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. CNR, Ist Astrofis Spaziale & Fis Cosm, I-40129 Bologna, Italy. Univ Ferrara, Dept Phys, I-44100 Ferrara, Italy. CNR, Ist Astrofis Spaziale, I-00133 Rome, Italy. RP Bloom, JS (reprint author), CALTECH, Div Phys Math & Astron, MS 105-24, Pasadena, CA 91125 USA. RI Kimble, Randy/D-5317-2012; Galama, Titus/D-1429-2014; 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 50 TC 143 Z9 145 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 10 PY 2002 VL 572 IS 1 BP L45 EP L49 DI 10.1086/341551 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 559BW UT WOS:000176005600010 ER PT J AU Gopalswamy, N Yashiro, S Michalek, G Kaiser, ML Howard, RA Reames, DV Leske, R von Rosenvinge, T AF Gopalswamy, N Yashiro, S Michalek, G Kaiser, ML Howard, RA Reames, DV Leske, R von Rosenvinge, T TI Interacting coronal mass ejections and solar energetic particles SO ASTROPHYSICAL JOURNAL LA English DT Article DE solar-terrestrial relations; Sun : corona; Sun : coronal mass ejections (CMEs); Sun : particle emission; Sun : radio radiation ID RADIO; SUN AB We studied the association between solar energetic particle (SEP) events and coronal mass ejections (CMEs) and found that CME interaction is an important aspect of SEP production. Each SEP event was associated with a primary CME that is faster and wider than average CMEs and originated from west of E45degrees. For most of the SEP events, the primary CME overtakes one or more slower CMEs within a heliocentric distance of similar to20 R-circle dot. In an inverse study, we found that for all the fast (speed greater than 900 km s(-1)) and wide (width greater than 60degrees) western hemispheric frontside CMEs during the study period, the SEP-associated CMEs were similar to4 times more likely to be preceded by CME interaction than the SEP-poor CMEs; i.e., CME interaction is a good discriminator between SEP-poor and SEP-associated CMEs. We infer that the efficiency of the CME-driven shocks is enhanced as they propagate through the preceding CMEs and that they accelerate SEPs from the material of the preceding CMEs rather than from the quiet solar wind. We also found a high degree of association between major SEP events and interplanetary type II radio bursts, suggesting that proton accelerators are also good electron accelerators. C1 NASA, Goddard Space Flight Ctr, LEP, Greenbelt, MD 20771 USA. Catholic Univ Amer, Ctr Solar Phys & Space Weather, Washington, DC 20064 USA. USN, Res Lab, Washington, DC 20375 USA. CALTECH, Pasadena, CA 91125 USA. RP Gopalswamy, N (reprint author), NASA, Goddard Space Flight Ctr, LEP, Greenbelt, MD 20771 USA. RI Gopalswamy, Nat/D-3659-2012 NR 11 TC 134 Z9 137 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 10 PY 2002 VL 572 IS 1 BP L103 EP L107 DI 10.1086/341601 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 559BW UT WOS:000176005600023 ER PT J AU Lowrance, PJ Kirkpatrick, JD Beichman, CA AF Lowrance, PJ Kirkpatrick, JD Beichman, CA TI A distant stellar companion in the nu Andromedae system SO ASTROPHYSICAL JOURNAL LA English DT Article DE astrometry; binaries : visual; planetary systems; stars : individual (nu Andromedae); stars : low-mass, brown dwarfs ID UPSILON-ANDROMEDAE; PLANETARY SYSTEM; DWARF COMPANIONS; STARS; STABILITY; ECCENTRICITY AB Upsilon Andromedae is an F8 V star known to have an extrasolar system of at least three planets in orbit around it. Here we report the discovery of a low-mass stellar companion to this system. The companion shares common proper motion, lies at a projected separation of similar to750 AU, and has a spectral type of M4.5 V. The effect of this star on the radial velocity of the brighter primary is negligible, but this system provides an interesting test bed for stellar planetary formation theory and understanding dynamical stability since it is the first multiple planetary system known in a multiple stellar system. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Ctr Infrared Proc & Anal, Pasadena, CA 91125 USA. RP Lowrance, PJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM lowrance@ipac.caltech.edu NR 24 TC 24 Z9 24 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 10 PY 2002 VL 572 IS 1 BP L79 EP L81 DI 10.1086/341554 PN 2 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 559BW UT WOS:000176005600017 ER PT J AU Polenta, G Ade, PAR Bock, JJ Bond, JR Borrill, J Boscaleri, A Contaldi, CR Crill, BP de Bernardis, P De Gasperis, G De Troia, G Ganga, K Giacometti, M Hivon, E Hristov, VV Jaffe, AH Lange, AE Masi, S Mauskopf, PD Melchiorri, A Montroy, T Natoli, P Netterfield, CB Pascale, E Piacentini, F Pogosyan, D Prunet, S Romeo, G Ruhl, JE Vittorio, N Zeppilli, A AF Polenta, G Ade, PAR Bock, JJ Bond, JR Borrill, J Boscaleri, A Contaldi, CR Crill, BP de Bernardis, P De Gasperis, G De Troia, G Ganga, K Giacometti, M Hivon, E Hristov, VV Jaffe, AH Lange, AE Masi, S Mauskopf, PD Melchiorri, A Montroy, T Natoli, P Netterfield, CB Pascale, E Piacentini, F Pogosyan, D Prunet, S Romeo, G Ruhl, JE Vittorio, N Zeppilli, A TI Search for non-Gaussian signals in the BOOMERANG maps: Pixel-space analysis SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic microwave background ID MICROWAVE BACKGROUND-RADIATION; GALACTIC DUST EMISSION; ANISOTROPY; INFLATION; UNIVERSE AB We search the BOOMERANG (Balloon Observations Of Millimetric Extragalactic Radiation ANd Geophysics) maps of the anisotropy of the cosmic microwave background (CMB) for deviations from Gaussianity. In this Letter, we focus on analysis techniques in pixel space and compute skewness, kurtosis, and Minkowski functionals for the BOOMERANG maps and for Gaussian simulations of the CMB sky. We do not find any significant deviation from Gaussianity in the high galactic latitude section of the 150 GHz map. We do find deviations from Gaussianity at lower latitudes and at 410 GHz, and we ascribe them to Galactic dust contamination. Using non-Gaussian simulations of instrumental systematic effects, of foregrounds, and of sample non-Gaussian cosmological models, we set upper limits to the non-Gaussian component of the temperature field in the BOOMERANG maps. For fluctuations distributed as a 1 degree of freedom chi(2) mixed to the main Gaussian component, our upper limits are in the few percentile range. C1 Univ Roma La Sapienza, Dipartimento Fis, I-00185 Rome, Italy. Queen Mary Univ London, London E1 4NS, England. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Toronto, Canadian Inst Theoret Astrophys, Toronto, ON M5S 3H8, Canada. Univ Calif Berkeley, Lawrence Berkeley Lab, Natl Energy Res Sci Comp Ctr, Berkeley, CA 94720 USA. CNR, IROE, I-50127 Florence, Italy. CALTECH, Dept Phys, Pasadena, CA 91125 USA. Univ Roma Tor Vergata, Dipartimento Fis, I-00133 Rome, Italy. CALTECH, Ctr Infrared Proc & Anal, Pasadena, CA 91125 USA. Univ London Imperial Coll Sci Technol & Med, Blackett Lab, Astrophys Grp, London SW7 2BZ, England. Cardiff Univ, Dept Phys & Astron, Cardiff CF24 3YB, S Glam, Wales. Univ Oxford, Nucl & Astrophys Lab, Oxford OX1 3RH, England. Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. Univ Toronto, Dept Astron & Astrophys, Toronto, ON M5S 3H8, Canada. Ist Nazl Geofis & Vulcanol, I-00143 Rome, Italy. RP Univ Roma La Sapienza, Dipartimento Fis, Piazzale Aldo Moro 2, I-00185 Rome, Italy. RI Jaffe, Andrew/D-3526-2009; de Gasperis, Giancarlo/C-8534-2012; Piacentini, Francesco/E-7234-2010; OI de Gasperis, Giancarlo/0000-0003-2899-2171; Piacentini, Francesco/0000-0002-5444-9327; Polenta, Gianluca/0000-0003-4067-9196; Melchiorri, Alessandro/0000-0001-5326-6003; Hivon, Eric/0000-0003-1880-2733 NR 29 TC 44 Z9 44 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD JUN 10 PY 2002 VL 572 IS 1 BP L27 EP L31 DI 10.1086/341484 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 559BW UT WOS:000176005600007 ER PT J AU Price, PA Berger, E Reichart, DE Kulkarni, SR Yost, SA Subrahmanyan, R Wark, RM Wieringa, MH Frail, DA Bailey, J Boyle, B Corbett, E Gunn, K Ryder, SD Seymour, N Koviak, K McCarthy, P Phillips, M Axelrod, TS Bloom, JS Djorgovski, SG Fox, DW Galama, TJ Harrison, FA Hurley, K Sari, R Schmidt, BP Brown, MJI Cline, T Frontera, F Guidorzi, C Montanari, E AF Price, PA Berger, E Reichart, DE Kulkarni, SR Yost, SA Subrahmanyan, R Wark, RM Wieringa, MH Frail, DA Bailey, J Boyle, B Corbett, E Gunn, K Ryder, SD Seymour, N Koviak, K McCarthy, P Phillips, M Axelrod, TS Bloom, JS Djorgovski, SG Fox, DW Galama, TJ Harrison, FA Hurley, K Sari, R Schmidt, BP Brown, MJI Cline, T Frontera, F Guidorzi, C Montanari, E TI GRB 011121: A massive star progenitor SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts ID GAMMA-RAY BURST; 25 APRIL 1998; ULTRAVIOLET EXTINCTION; UNUSUAL SUPERNOVA; STANDARD STARS; AFTERGLOWS; CURVES; EMISSION AB Of the cosmological gamma-ray bursts, GRB 011121 has the lowest redshift, z = 0.36. More importantly, the multicolor excess in the afterglow detected in the Hubble Space Telescope (HST) light curves is compelling observational evidence of an underlying supernova. Here we present near-infrared and radio observations of the afterglow, and from our comprehensive afterglow modeling, we find evidence favoring a wind-fed circumburst medium. Lacking X-ray data, we are unable to conclusively measure the mass-loss rate, M,but obtain an estimate, (M) over dot similar to 2 x 10(-7)/nu(w3) M. yr(-1), M, where nu(w3) is the speed of the wind from the progenitor in units of 10(3) km s(-1). This (M) over dot is similar to that inferred for the progenitor of the Type Ibc supernova SN 1998bw that has been associated M with the peculiar burst GRB 980425. Our data, taken in conjunction with the HST results of Bloom et al., provide a consistent picture: the long-duration GRB 011121 had a massive star progenitor that exploded as a supernova at about the same time as the gamma-ray burst event. Finally, we note that the gamma-ray profile of GRB 011121 is similar to that of GRB 980425. C1 Mt Stromlo & Siding Spring Observ, Res Sch Astron & Astrophys, Canberra, ACT 2611, Australia. CALTECH, Palomar Observ, Pasadena, CA 91125 USA. CSIRO, Australia Telescope Natl Facil, Epping, NSW 1710, Australia. Natl Radio Astron Observ, Socorro, NM 87801 USA. Anglo Australian Observ, Epping, NSW 1710, Australia. Univ Southampton, Dept Phys & Astron, Southampton SO17 1BJ, Hants, England. Carnegie Observ, Pasadena, CA 91101 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Natl Opt Astron Observ, Tucson, AZ 85726 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. CNR, Ist Tecnol & Studio Radiaz Extraterr, I-40129 Bologna, Italy. Univ Ferrara, Dipartmento Fis, I-44100 Ferrara, Italy. RP Price, PA (reprint author), Mt Stromlo & Siding Spring Observ, Res Sch Astron & Astrophys, Cotter Rd,Weston Creek, Canberra, ACT 2611, Australia. RI Subrahmanyan, Ravi/B-6079-2009; Astronomy & Astrophysics Group, Raman Res Institute/D-4046-2012; Subrahmanyan, Ravi/D-4889-2012; Galama, Titus/D-1429-2014; Brown, Michael/B-1181-2015; OI Galama, Titus/0000-0002-1036-396X; Brown, Michael/0000-0002-1207-9137; Schmidt, Brian/0000-0001-6589-1287; Schmidt, Brian/0000-0002-8538-9195; Ryder, Stuart/0000-0003-4501-8100 NR 36 TC 81 Z9 83 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 10 PY 2002 VL 572 IS 1 BP L51 EP L55 DI 10.1086/341552 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 559BW UT WOS:000176005600011 ER PT J AU Bijl, H Carpenter, MH Vatsa, VN Kennedy, CA AF Bijl, H Carpenter, MH Vatsa, VN Kennedy, CA TI Implicit time integration schemes for the unsteady compressible Navier-Stokes equations: Laminar flow SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article ID CYLINDER; SIMULATION AB The accuracy and efficiency of several lower and higher order time integration schemes are investigated for engineering solution of the discretized unsteady compressible Navier-Stokes equations. Fully implicit methods tested are either the backward differentiation formulas (BDF) or stage-order two. explicit, singly diagonally implicit Runge-Kutta (ESDIRK) methods. For this comparison an unsteady two-dimensional laminar flow problem is chosen: flow around a circular cylinder at Re = 1200. At temporal error tolerances consistent with engineering simulation. E approximate to 10(-1)-10(-2). first-order implicit Fuler (BDFI) is uncompetitive. While BDF3 is quite efficient, its lack of A-stability may be problematic in the presence of convection. At these same error tolerances, the fourth-order ESDIRK scheme is 2.5 times more efficient than BDF2. It is concluded that reliable integration is most efficiently provided by fourth-order Runge-Kutta methods for this problem where order reduction is not observed. Efficiency gains are more dramatic at smaller tolerances. (C) 2002 Elsevier Science (USA). C1 Delft Univ Technol, Dept Aerosp Engn, Delft, Netherlands. NASA, Langley Res Ctr, Computat Method & Simulat Branch, Hampton, VA 23681 USA. Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA. RP Bijl, H (reprint author), Delft Univ Technol, Dept Aerosp Engn, Delft, Netherlands. NR 18 TC 59 Z9 61 U1 0 U2 4 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 JUN 10 PY 2002 VL 179 IS 1 BP 313 EP 329 DI 10.1006/jcph.2002.7059 PG 17 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 561AN UT WOS:000176113900015 ER PT J AU Fukami-Kobayashi, K Schreiber, DR Benner, SA AF Fukami-Kobayashi, K Schreiber, DR Benner, SA TI Detecting compensatory covariation signals in protein evolution using reconstructed ancestral sequences SO JOURNAL OF MOLECULAR BIOLOGY LA English DT Article DE functional genomics; molecular evolution; structural biology; compensatory covariation; mutation; natural selection ID SECONDARY STRUCTURE; CORRELATED MUTATIONS; RIBONUCLEASE; PREDICTION; LIKELIHOOD; RECOGNITION; ALIGNMENTS; DIVERGENCE; FAMILIES; GENOMICS AB When protein sequences divergently evolve under functional constraints, some individual amino acid replacements that reverse the charge (e.g. Lys to Asp) may be compensated by a replacement at a second position that reverses the charge in the opposite direction (e.g. Glu to Arg). When these side-chains are near in space (proximal), such double replacements might be driven by natural selection, if either is selectively disadvantageous, but both together restore fully the ability of the protein to contribute to fitness (are together "neutral"). Accordingly, many have sought to identify pairs of positions in a protein sequence that suffer compensatory replacements, often as a way to identify positions near in space in the folded structure. A "charge compensatory signal" might manifest itself in two ways. First, proximal charge compensatory replacements may occur more frequently than predicted from the product of the probabilities of individual positions suffering charge reversing replacements independently. Conversely, charge compensatory pairs of changes may be observed to occur more frequently in proximal pairs of sites than in the average pair. Normally, charge compensatory covariation is detected by comparing the sequences of extant proteins at the "leaves" of phylogenetic trees. We show here that the charge compensatory signal is more evident when it is sought by examining individual branches in the tree between reconstructed ancestral sequences at nodes in the tree. Here, we find that the signal is especially strong when the positions pairs are in a single secondary structural unit (e.g. ut helix or P strand) that brings the side-chains suffering charge compensatory covariation near in space, and may be useful in secondary structure prediction. Also, "node-node" and "node-leaf" compensatory covariation may be useful to identify the better of two equally parsimonious trees, in a way that is independent of the mathematical formalism used to construct the tree itself. Further, compensatory covariation may provide a signal that indicates whether an episode of sequence evolution contains more or less divergence in functional behavior. Compensatory covariation analysis on reconstructed evolutionary trees may become a valuable tool to analyze genome sequences, and use these analyses to extract biomedically useful information from proteome databases. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 Univ Florida, Dept Chem, Gainesville, FL 32611 USA. Univ Florida, Dept Anat & Cell Biol, Gainesville, FL 32611 USA. Univ Florida, NASA Astrobiol Inst, Gainesville, FL 32611 USA. Natl Inst Genet, Ctr Informat Biol, Mishima, Shizuoka 4118540, Japan. Natl Inst Genet, DNA Data Bank Japan, Mishima, Shizuoka 4118540, Japan. Fdn Sci Inquiry, Gainesville, FL 32604 USA. RP Benner, SA (reprint author), Univ Florida, Dept Chem, Gainesville, FL 32611 USA. RI Fukami, Kaoru/N-7896-2015 FU NIGMS NIH HHS [R41 GM063368, R41 GM063368-01]; NIMH NIH HHS [MH 55479, R42 MH055479, R42 MH055479-03] NR 46 TC 43 Z9 45 U1 0 U2 3 PU ACADEMIC PRESS LTD ELSEVIER SCIENCE LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-2836 J9 J MOL BIOL JI J. Mol. Biol. PD JUN 7 PY 2002 VL 319 IS 3 BP 729 EP 743 DI 10.1016/S0022-2836(02)00239-5 PG 15 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 565QB UT WOS:000176380000011 PM 12054866 ER PT J AU Gindulyte, A Massa, L Banks, BA Miller, SKR AF Gindulyte, A Massa, L Banks, BA Miller, SKR TI Direct C-C bond breaking in the reaction of O(P-3) with flouropolymers in low earth orbit SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID HYPERTHERMAL ATOMIC OXYGEN; SPACECRAFT MATERIALS; POLYMERS; DEGRADATION AB Spacecraft flying in low Earth orbit (LEO) are exposed to a harsh environment which includes frequent bombardment by fast atomic oxygen (AO) and ultraviolet (UV) radiation. As a result, many spacecraft surface materials are severely eroded. In the case of fluoropolymers, a controversy exists whether AO or UV or AO/UV synergy is responsible for the degradation. In this study, with the use of ab initio calculations, we address the question whether the most abundant species in LEO, viz., atomic oxygen in its ground state, O(P-3), alone can cause the degradation in fluoropolymer materials. The smallest fluorocarbons CNF2N+2 (N = 2, 3, 5) serve as models of fluoropolymers. Since electronegativity of fluorine seems to preclude F-abstraction by O(P-3), we concentrate on direct O(P-3) attacks on carbon-carbon bonds. For the case of fluoroethane (N = 2), we explore the triplet potential energy surface of the following reaction: O(P-3) + CF3-CF3 --> O-.-CF3 + (CF3)-C-.. Analogous reactions, where O(P-3) attacks a central carbon atom, are studied for the higher fluorocarbons. Results obtained using the Hartree-Fock method and density functional theory are reported. We conclude that O(P-3) species in LEO possesses enough translational energy to degrade fluorocarbon materials. C1 CUNY Hunter Coll, Dept Chem, New York, NY 10021 USA. CUNY, Grad Sch, New York, NY 10016 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Massa, L (reprint author), CUNY Hunter Coll, Dept Chem, 695 Pk Ave, New York, NY 10021 USA. NR 36 TC 19 Z9 19 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD JUN 6 PY 2002 VL 106 IS 22 BP 5463 EP 5467 DI 10.1021/jp0132578 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 559WT UT WOS:000176049600008 ER PT J AU Delzeit, L Nguyen, CV Chen, B Stevens, R Cassell, A Han, J Meyyappan, M AF Delzeit, L Nguyen, CV Chen, B Stevens, R Cassell, A Han, J Meyyappan, M TI Multiwalled carbon nanotubes by chemical vapor deposition using multilayered metal catalysts SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID GROWTH; SINGLE; MORPHOLOGY; ARRAYS; FILM AB Multiwalled carbon nanotubes (MWCNTs) have been grown on various substrates by thermal chemical vapor deposition using multilayered metal catalysts. Ion beam sputtering is used to deposit various metal layers sequentially. Underlayer, of Al (2-20 nm) are shown to influence the growth characteristics with Fe or Ni used as active catalysts. The as-sputtered catalyst surface, characterized using atomic force and scanning tunneling microscopics, consists of nanometer scale (<10 nm) catalyst particles. High-resolution transmission electron microscopy and Raman analysis are used to characterize the MWCNTs. Optimization of the two layers allows growth of MWCNT towers on patterned and unpatterned substrates. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Delzeit, L (reprint author), NASA, Ames Res Ctr, MS 239-4, Moffett Field, CA 94035 USA. NR 21 TC 109 Z9 110 U1 4 U2 27 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 JUN 6 PY 2002 VL 106 IS 22 BP 5629 EP 5635 DI 10.1021/jp0203898 PG 7 WC Chemistry, Physical SC Chemistry GA 559WU UT WOS:000176049700008 ER PT J AU Rothschild, L AF Rothschild, L TI Life at the limits: Organisms in extreme environments SO NATURE LA English DT Book Review 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 1 TC 1 Z9 1 U1 2 U2 26 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD JUN 6 PY 2002 VL 417 IS 6889 BP 593 EP 593 DI 10.1038/417593a PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 559AE UT WOS:000176001200024 ER PT J AU Anjali, T Scoglio, C de Oliveira, JC Akyildiz, IF Uhl, G AF Anjali, T Scoglio, C de Oliveira, JC Akyildiz, IF Uhl, G TI Optimal policy for label switched path setup in MPLS networks SO COMPUTER NETWORKS LA English DT Article DE LSP establishment; LSP re-dimensioning; MPLS; MPLS network topology AB An important aspect in designing a multiprotocol label switching (MPLS) network is to determine an initial topology and to adapt it to the traffic load. A topology change in an MPLS network occurs when a new label switched path (LSP) is created between two nodes. The LSP creation involves determining the route of the LSP and the according resource allocation to the path. A fully connected MPLS network can be used to minimize the signaling. The objective of this paper is to determine when an LSP should be created and how often it should be re-dimensioned. An optimal policy to determine and adapt the MPLS network topology based on the traffic load is presented. The problem is formulated as a continuous time Markov decision process with the objective to minimize the costs involving bandwidth, switching, and signaling. These costs represent the trade-off between utilization of network resources and signaling/processing load incurred on the network. The policy performs a filtering control to avoid oscillations which may occur due to highly variable traffic. The new policy has been evaluated by simulation and numerical results show its effectiveness and the according performance improvement. A sub-optimal policy is also presented which is less computationally intensive and complicated. (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, Beltsville, MD 20705 USA. Swales Aerosp, Beltsville, MD 20705 USA. RP Anjali, T (reprint author), Georgia Inst Technol, Sch Elect & Comp Engn, Broadband & Wireless Networking Lab, 250 14th St, Atlanta, GA 30332 USA. EM tricha@ece.gatech.edu; caterina@ece.gatech.edu; jau@ece.gatech.edu; ian@ece.gatech.edu; uhl@rattler-e.gsfc.nasa.gov RI Akyildiz, Ian/G-7136-2011 OI Akyildiz, Ian/0000-0002-8099-3529 NR 10 TC 23 Z9 23 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1389-1286 J9 COMPUT NETW JI Comput. Netw. PD JUN 5 PY 2002 VL 39 IS 2 BP 165 EP 183 AR PII S1389-1286(01)00308-5 DI 10.1016/S1389-1286(01)00308-5 PG 19 WC Computer Science, Hardware & Architecture; Computer Science, Information Systems; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA 554DW UT WOS:000175719400005 ER PT J AU Barlow, S Henling, LM Day, MW Schaefer, WP Green, JC Hascall, T Marder, SR AF Barlow, S Henling, LM Day, MW Schaefer, WP Green, JC Hascall, T Marder, SR TI Metallocene-terminated allylium salts: The effect of end group on localization in polymethines SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID NEGATIVE-DEFECT TRANSPOLYACETYLENE; MIXED-VALENCE COMPLEXES; MOLECULAR-STRUCTURE; CRYSTAL-STRUCTURE; ROOM-TEMPERATURE; FINITE-LENGTH; CATIONS; DERIVATIVES; FERROCENE; SOLITONS AB A range of 1,3-di (metallocenyl)allylium salts [Mc(CH)(3)Mc'](+)[X](-) (Mc, Mc' = ferrocenyl (Fc), 2,3,4,5,1',2',3',4'-octamethylferrocen-1-yI (Fc"), ruthenocenyl (Rc); X = BF4, PF6} was synthesized by reaction of (2-lithiovinyl) metallocenes with formylmetallocenes, followed by treatment of the resulting alcohols with HX. Two salts with X = BAr'(4) {Ar' = 3,5-(CF3)(2)C6H3} were synthesized by anion metathesis from the corresponding PF6, salts. The crystal structure of [Fc"(CH)(3)Fc"](+)[PF6](-) contains symmetrical termethine cations, while the same appears to be true in the disordered structure of [Fc(CH)(3)Fc](+)[PF6](-). The formally unsymmetrical cation in [Fc(CH)(3)Fc"](+)[BF4](-) is only slightly unsymmetrical with little bond-length alternation in the allylium bridge. In contrast, the crystal structures of [Rc(CH)(3)Rc](-)[PF6](-) and [Rc(CH)(3)Rc](-)[BAr'(4)](-) both contain a bond-alternated "Peierls-distorted" cation, which can be considered as a ruthenocene bridged to a [(eta(6)-fulvene)(eta(5-)cylopentadienyl) ruthenium] cation by a vinylene moiety. The strong similarity between solid-state and solution infrared and Raman spectra of [BF4](-) [PF6](-) and [BAr4](-) salts of [Rc(CH)(3)Rc](+) indicates that the C-C stretching constant in the allylium chain and, therefore, the structure, of this ion are largely independent of the local environment, suggesting that the unsymmetrical structures observed in the crystal structures are not simply an artifact of packing. Differences in the solvatochromism of [Rc(CH)3Rc]l and [Fc(CH)(3)Fc]- also suggest a localized structure for the former cation in solution. Electrochemistry, UV-visible-NIR spectroscopy, and DF calculations give insight into the electronic structure of the metallocene-terminated allylium cations. Using an analogy between polymethines and mixed-valence compounds, the difference between the behaviors of [Fc(CH)(3)Fc](+) and [Rc(CH)(3)Rc](+) is attributed to larger reorganization energy associated with the geometry differences between metallocene and [(eta(6)-fulvene)(eta(5)-cyclopentadienyl) metal] structures in the ruthenium case. C1 Univ Arizona, Dept Chem, Tucson, AZ 85721 USA. CALTECH, Beckman Inst, Pasadena, CA 91125 USA. Univ Oxford, Inorgan Chem Lab, Oxford OX1 3RQ, England. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Barlow, S (reprint author), Univ Arizona, Dept Chem, Tucson, AZ 85721 USA. RI Barlow, Stephen/E-9754-2010 NR 71 TC 27 Z9 27 U1 0 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD JUN 5 PY 2002 VL 124 IS 22 BP 6285 EP 6296 DI 10.1021/ja012472z PG 12 WC Chemistry, Multidisciplinary SC Chemistry GA 558FC UT WOS:000175954800018 PM 12033856 ER PT J AU Chen, CT Seneor, P Yeh, NC Vasquez, RP Bell, LD Jung, CU Kim, JY Park, MS Kim, HJ Lee, SI AF Chen, CT Seneor, P Yeh, NC Vasquez, RP Bell, LD Jung, CU Kim, JY Park, MS Kim, HJ Lee, SI TI Strongly correlated s-wave superconductivity in the N-type infinite-layer cuprate SO PHYSICAL REVIEW LETTERS LA English DT Article ID HIGH-TEMPERATURE SUPERCONDUCTORS; PAIRING SYMMETRY; IMPURITY ATOMS; STATES; BI2SR2CACU2O8+DELTA; SR0.9LA0.1CUO2; SPECTRA; PROBE; ZN AB Quasiparticle tunneling spectra of the electron-doped (n -type) infinite-layer cuprate Sr0.9La 0.1CuO2 reveal characteristics that counter a number of common phenomena in the hole-doped (p-type) cuprates. The optimally doped Sr0.9La 0.1CuO2 with T-c = 43 K exhibits a momentum-independent superconducting gap Delta = 13.0 +/- 1.0 meV that substantially exceeds the BCS value, and the spectral characteristics indicate insignificant quasiparticle damping by spin fluctuations and the absence of pseudogap. The response to quantum impurities in the Cu sites also differs fundamentally from that of the p-type cuprates with d(x2-y2)-wave pairing symmetry. C1 CALTECH, Dept Phys, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Pohang Univ Sci & Technol, Dept Phys, Pohang 790784, South Korea. Pohang Univ Sci & Technol, Natl Creat Res Initiat Ctr Superconduct, Pohang 790784, South Korea. RP CALTECH, Dept Phys, Pasadena, CA 91125 USA. NR 32 TC 67 Z9 67 U1 0 U2 12 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 EI 1079-7114 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 3 PY 2002 VL 88 IS 22 AR 227002 DI 10.1103/PhysRevLett.88.227002 PG 4 WC Physics, Multidisciplinary SC Physics GA 553ZW UT WOS:000175709100039 PM 12059447 ER PT J AU Penley, NJ Schafer, CP Bartoe, JDF AF Penley, NJ Schafer, CP Bartoe, JDF TI The International Space Station as a microgravity research platform SO ACTA ASTRONAUTICA LA English DT Article AB The International Space Station will provide a "World Class" environment for microgravity research. Ensuring this environment requires care in all aspects of its design. These aspects include consideration of the acceleration at near-orbit-tune-periods, such as gravity gradients and station drag, as well as controlling station structural dynamic modes. mechanical disturbances, and crew disturbances. Station designers must also ensure that the required acceleration environment is provided for long duration. The microgravity requirements placed on ISS will be reviewed, along with major considerations for achieving such an environment. Further, a description of the Space Station program strategy and implementation for meeting those requirements will be discussed. (C) 2002 Published by Elsevier Science Ltd. C1 NASA, Johnson Space Ctr, Houston, TX 77058 USA. RP Penley, NJ (reprint author), NASA, Johnson Space Ctr, Houston, TX 77058 USA. NR 5 TC 9 Z9 11 U1 1 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD JUN PY 2002 VL 50 IS 11 BP 691 EP 696 DI 10.1016/S0094-5765(02)00003-6 PG 6 WC Engineering, Aerospace SC Engineering GA 566LU UT WOS:000176430200005 PM 12035811 ER PT J AU Buzzard, FT Schmidt, OL AF Buzzard, FT Schmidt, OL TI ISS communications enhancement plan SO ACTA ASTRONAUTICA LA English DT Article AB The capabilities of the International Space Station (ISS) communications system will be expanded to enhance the capability of scientists and principal investigators in controlling and obtaining data from their payloads. Payload user requirements exceed the current capabilities of the ISS communications system. This paper describes a phased approach that will significantly expand the ISS communications system capability and enable payload telescience objectives. A Ku-Band forward link will be added for uplink voice, video and commands to Support telescience. Increased demands on return link bandwidth will require the use of video compression to free up more bandwidth for payload data. Standard video compression algorithms such as MPEG 2 will be used to facilitate transmission compressed digital video to the end user. Ground data processing capabilities upgrades will be pursued to increase the downlink data rates from 50 to 150 Mbps. A new communication outage recorder will store payload data when the Space Station is not in view of a data relay satellite. The enhanced communication capability and ground data handling capability enhancements will be carefully matched to the expanding payload user requirements. The final phase of the ISS communication enhancement plan will investigate the feasibility of greatly increased bandwidth using commercially developed, state-of-the-art systems. Published by Elsevier Science Ltd. C1 NASA, Johnson Space Ctr, Houston, TX 77058 USA. RP Buzzard, FT (reprint author), NASA, Johnson Space Ctr, Houston, TX 77058 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD JUN PY 2002 VL 50 IS 11 BP 697 EP 703 AR PII S0094-5765(02)00002-4 DI 10.1016/S0094-5765(02)00002-4 PG 7 WC Engineering, Aerospace SC Engineering GA 566LU UT WOS:000176430200006 ER PT J AU Montenbruck, O Markgraf, M Jung, WG Bull, B Engler, W AF Montenbruck, O Markgraf, M Jung, WG Bull, B Engler, W TI GPS based prediction of the instantaneous impact point for sounding rockets SO AEROSPACE SCIENCE AND TECHNOLOGY LA English DT Article DE instantaneous impact point; GPS; sounding rockets AB As part of the range safety operations during a sounding rocket launch, a real-time prediction of the instantaneous impact point (IIP) is performed to monitor the expected touch down point in case of a boost termination. Supplementary to traditional radar tracking, the IIP prediction is nowadays based on GPS navigation data; which offer an inherently higher accuracy and reduced data noise. To comply with the increased tracking performance, a consistent set of equations suitable for real-time computation of the approximate IIP is established. Aside from a consideration of gravitational forces, reference frame rotation and Earth curvature, the model can also account for drag during the ascent trajectory provided that a priori information on the ballistic properties of the launch vehicle is available. The algorithm is tested for a representative set of mission profiles and applied to GPS flight data of an Improved Orion rocket and a Maxus rocket launched at Esrange, Kiruna. (C) 2002 Editions scientifiques et medicales Elsevier SAS. All rights reserved. C1 Deutsch Zentrum Luft & Raumfahrt, German Space Operat Ctr, D-82230 Wessling, Germany. NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Wallops Isl, VA 23337 USA. Kayser Threde GmbH, D-81379 Munich, Germany. RP Montenbruck, O (reprint author), Deutsch Zentrum Luft & Raumfahrt, German Space Operat Ctr, D-82230 Wessling, Germany. OI Montenbruck, Oliver/0000-0003-4783-745X NR 14 TC 12 Z9 12 U1 0 U2 2 PU EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER PI PARIS CEDEX 15 PA 23 RUE LINOIS, 75724 PARIS CEDEX 15, FRANCE SN 1270-9638 J9 AEROSP SCI TECHNOL JI Aerosp. Sci. Technol. PD JUN PY 2002 VL 6 IS 4 BP 283 EP 294 AR PII S1270-9638(02)01163-X DI 10.1016/S1270-9638(02)01163-X PG 12 WC Engineering, Aerospace SC Engineering GA 576AK UT WOS:000176980500004 ER PT J AU Chien, S Hirsh, H AF Chien, S Hirsh, H TI The Fourteenth Innovative Applications of Artificial Intelligence Conference (IAAI-2001) SO AI MAGAZINE LA English DT Editorial Material C1 CALTECH, Jet Prop Lab, Artificial Intelligence Grp, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Explorat Syst Auton Sect, Pasadena, CA 91125 USA. Rutgers State Univ, Piscataway, NJ 08855 USA. RP Chien, S (reprint author), CALTECH, Jet Prop Lab, Artificial Intelligence Grp, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER ASSOC ARTIFICIAL INTELL PI MENLO PK PA 445 BURGESS DRIVE, MENLO PK, CA 94025-3496 USA SN 0738-4602 J9 AI MAG JI AI Mag. PD SUM PY 2002 VL 23 IS 2 BP 9 EP 10 PG 2 WC Computer Science, Artificial Intelligence SC Computer Science GA 633NB UT WOS:000180288400001 ER PT J AU Smith, BD Engelhardt, BE Mutz, DH AF Smith, BD Engelhardt, BE Mutz, DH TI The RADARSAT-MAMM automated mission planner SO AI MAGAZINE LA English DT Article; Proceedings Paper CT 14th Innovative Applications of Artificial Intelligence Conference (IAAI-2001) CY AUG 07-09, 2001 CL SEATTLE, WASHINGTON AB The Modified Antarctic Mapping Mission (MAMM) was conducted from September to November 2000 onboard RADARSAT. The mission plan consisted of more than 2400 synthetic aperture radar data acquisitions of Antarctica that achieved the scientific objectives and obeyed RADARSAT's resource and operational constraints. Mission planning is a time- and knowledge-intensive effort. It required over a workyear to manually develop a comparable plan for AMM-1, the precursor mission to MAMM. This article describes the design and use of the automated mission planning system for MAMM, which dramatically reduced mission-planning costs to just a few workweeks and enabled rapid generation of what-if scenarios for evaluating alternative mission designs. C1 Jet Propuls Lab, Autonomy Technol Program, Pasadena, CA 91109 USA. Univ Calif Berkeley, Berkeley, CA 94720 USA. RP Smith, BD (reprint author), Jet Propuls Lab, Autonomy Technol Program, Pasadena, CA 91109 USA. NR 7 TC 4 Z9 4 U1 1 U2 1 PU AMER ASSOC ARTIFICIAL INTELL PI MENLO PK PA 445 BURGESS DRIVE, MENLO PK, CA 94025-3496 USA SN 0738-4602 J9 AI MAG JI AI Mag. PD SUM PY 2002 VL 23 IS 2 BP 25 EP 36 PG 12 WC Computer Science, Artificial Intelligence SC Computer Science GA 633NB UT WOS:000180288400003 ER PT J AU Humphreys, WM Naguib, AM AF Humphreys, WM Naguib, AM TI Comparative study of image compression techniques for digital particle image velocimetry SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT 39th Aerospace Sciences Meeting CY JAN 08-11, 2001 CL RENO, NEVADA AB A comparative, quantitative study of image compression techniques for use with digital particle image velocimetry has been performed. Several candidate compression algorithms were selected for the study, including a lossless technique and two mathematical transform-based methods. Each of the compression algorithms was implemented using commercial off-the-shelf software packages. Three image sequences were selected to exercise the various compression methods. These sequences included a set of industry standard images and two sets of images obtained from experimental work conducted at NASA Langley Research Center. Evaluation of the various methods was accomplished using quantitative perceptual and metrological performance measures. The results of the study indicate that several of the tested methods of compression are suitable for digital particle image velocimetry. A lossless LZ77 technique, coupled with pixel thresholding of image gray levels before compression, yielded excellent performance in terms of compression level and negligible introduction of spatial errors to the images. A lossy JPEG algorithm was shown to provide acceptable performance, however, significant spatial errors and increased numbers of false vectors derived from processing of the compressed images were observed at high compression levels. Finally, a lossy wavelet algorithm was shown to provide excellent performance in terms of minimal introduction of spatial errors and a reduction in the false vector rate over a wide range of compression levels. C1 NASA, Langley Res Ctr, Adv Measurement & Diagnost Branch, Hampton, VA 23681 USA. Michigan State Univ, Dept Mech Engn, E Lansing, MI 48824 USA. RP Humphreys, WM (reprint author), NASA, Langley Res Ctr, Adv Measurement & Diagnost Branch, Hampton, VA 23681 USA. NR 16 TC 1 Z9 1 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD JUN PY 2002 VL 40 IS 6 BP 1026 EP 1036 DI 10.2514/2.1766 PG 11 WC Engineering, Aerospace SC Engineering GA 557ZA UT WOS:000175938100002 ER PT J AU Liu, TS Barrows, DA Burner, AW Rhew, RD AF Liu, TS Barrows, DA Burner, AW Rhew, RD TI Determining aerodynamic loads based on optical deformation measurements SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT 39th Aerospace Sciences Meeting CY JAN 08-11, 2001 CL RENO, NEVADA AB A preliminary study is described for determining aerodynamic loads based on optical elastic deformation measurements using a videogrammetric system. Data reduction methods are developed and used to extract the normal force and pitching moment from beam deformation data. The axial force is obtained by measuring the axial translational motion of a movable shaft in a spring/bearing device. Proof-of-concept calibration experiments are conducted to assess the feasibility of the optical technique for measuring aerodynamic loads. The uncertainties in optical force and moment measurements are discussed. C1 NASA, Langley Res Ctr, Model Syst Branch, Hampton, VA 23681 USA. NASA, Langley Res Ctr, Instrumentat Syst Dev Branch, Hampton, VA 23681 USA. RP Liu, TS (reprint author), NASA, Langley Res Ctr, Model Syst Branch, Hampton, VA 23681 USA. NR 10 TC 4 Z9 4 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD JUN PY 2002 VL 40 IS 6 BP 1105 EP 1112 DI 10.2514/2.1759 PG 8 WC Engineering, Aerospace SC Engineering GA 557ZA UT WOS:000175938100013 ER PT J AU Nielsen, EJ Anderson, WK AF Nielsen, EJ Anderson, WK TI Recent improvements in aerodynamic design optimization on unstructured meshes SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT 39th Aerospace Sciences Meeting CY JAN 08-11, 2001 CL RENO, NEVADA ID ADJOINT FORMULATION; TURBULENT FLOWS; GRIDS; ALGORITHM; EQUATIONS; SCHEME AB Recent improvements in an unstructured-grid method for large-scale aerodynamic design are presented. Previous work had shown such computations to be prohibitively long in a sequential processing environment. Also, robust adjoint solutions and mesh movement procedures were difficult to realize, particularly for viscous flows. To overcome these limiting factors, a set of design codes based on a discrete adjoint method is extended to a multiprocessor environment using a shared memory approach. A nearly linear speedup is demonstrated, and the consistency of the linearizations is shown to remain valid. The full linearization of the residual is used to precondition the adjoint system, and a significantly improved convergence rate is obtained. A new mesh movement algorithm is implemented, and several advantages over an existing technique are presented. Several design cases are shown for turbulent flows in two and three dimensions. C1 NASA, Langley Res Ctr, Computat Modeling & Simulat Branch, Hampton, VA 23681 USA. RP Nielsen, EJ (reprint author), NASA, Langley Res Ctr, Computat Modeling & Simulat Branch, Mail Stop 128, Hampton, VA 23681 USA. NR 25 TC 74 Z9 80 U1 1 U2 6 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 JUN PY 2002 VL 40 IS 6 BP 1155 EP 1163 DI 10.2514/2.1765 PG 9 WC Engineering, Aerospace SC Engineering GA 557ZA UT WOS:000175938100019 ER PT J AU Juang, JN Kholodar, D Dowell, EH AF Juang, JN Kholodar, D Dowell, EH TI System identification of a vortex lattice aerodynamic model SO AIAA JOURNAL LA English DT Article ID UNSTEADY AB The state-space representation of an aerodynamic vortex lattice model is considered from a classical, system identification perspective. By the use of an aerodynamic vortex model as a numerical simulator of a wind-tunnel experiment, both full-state and limited-state data or measurements are considered. Two possible approaches for system identification are presented, and modal controllability and observability are also considered. The theory then is applied to the System identification of the however a delta wing, and typical results are presented. C1 NASA Langley Res Ctr, Hampton, VA 23681 USA. Duke Univ, Durham, NC 27708 USA. RP Juang, JN (reprint author), NASA Langley Res Ctr, Hampton, VA 23681 USA. NR 3 TC 4 Z9 4 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD JUN PY 2002 VL 40 IS 6 BP 1187 EP 1196 DI 10.2514/2.1770 PG 10 WC Engineering, Aerospace SC Engineering GA 557ZA UT WOS:000175938100023 ER PT J AU Xue, HS Aggarwal, SK Osborne, RJ Brown, TM Pitz, RW AF Xue, HS Aggarwal, SK Osborne, RJ Brown, TM Pitz, RW TI Assessment of reaction mechanisms for counterflow methane - Air partially premixed flames SO AIAA JOURNAL LA English DT Article C1 Univ Illinois, Chicago, IL 60607 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Vanderbilt Univ, Nashville, TN 37325 USA. RP Xue, HS (reprint author), Univ Illinois, Chicago, IL 60607 USA. RI Pitz, Robert/H-7868-2016 OI Pitz, Robert/0000-0001-6435-5618 NR 8 TC 16 Z9 16 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 JUN PY 2002 VL 40 IS 6 BP 1236 EP 1238 DI 10.2514/2.1778 PG 3 WC Engineering, Aerospace SC Engineering GA 557ZA UT WOS:000175938100030 ER PT J AU Smets, R Delcourt, D Chanteur, G Moore, TE AF Smets, R Delcourt, D Chanteur, G Moore, TE TI On the incidence of Kelvin-Helmholtz instability for mass exchange process at the Earth's magnetopause SO ANNALES GEOPHYSICAE LA English DT Article DE magnetospheric physics; magnetopause, cusp and boundary layers; MHD waves and instabilities; space plasma physics; numerical simulation studies ID MAGNETOSPHERIC BOUNDARY-LAYER; LATITUDE DAYSIDE MAGNETOPAUSE; HIGH MAGNETIC SHEAR; TANGENTIAL DISCONTINUITY; AMPTE/IRM OBSERVATIONS; PARTICLE ORBITS; FIELD ROTATION; PLASMA; RECONNECTION; INTERPLANETARY AB Due to the velocity shear imposed by the solar wind flowing around the magnetosphere. the magnetopause flanks are preferred regions for the development of a Kelvin-Helmholtz instability. Since its efficiency for momentum transfer across the magnetopause has already been established, we investigate its efficiency for mass transfer. Using nonresistive magnetohydrodynamic simulations to describe the magnetic field shape in the instability region, we use test-particle calculations to analyse particle dynamics. We show that the magnetopause thickness and the instability wavelength are too large to lead to nonadiabatic motion of thermal electrons from the magnetosphere. On the other hand, the large mass of H+, He+ and O+ ions leads to such nonadiabatic motion and we thus propose the Kelvin-Helmholtz instability as a mechanism for either magnetospheric ion leakage into the magnetosheath or solar wind ion entry in the magnetosphere, Test-particle calculations are performed in a dimensionless way to discuss the case of each type of ion. The crossing rate is of the order of 10%. This rate is anti-correlated with shear velocity and instability wavelength. It increases with the magnetic shear. The crossing regions at the magnetopause are narrow and localized in the vicinity of the instability wave front. As a Kelvin-Helmholtz instability allows for mass transfer through the magnetopause without any resistivity, we propose it as an alternate process to reconnection for mass transfer through magnetic boundaries. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. CNRS, CETP, Velizy Villacoublay, France. CNRS, CETP, St Maur des Fosses, France. RP Smets, R (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Moore, Thomas/D-4675-2012 OI Moore, Thomas/0000-0002-3150-1137 NR 50 TC 6 Z9 6 U1 0 U2 1 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 JUN PY 2002 VL 20 IS 6 BP 757 EP 769 PG 13 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA 570UG UT WOS:000176676200002 ER PT J AU Sidilkover, D AF Sidilkover, D TI Factorizable schemes for the equations of fluid flow SO APPLIED NUMERICAL MATHEMATICS LA English DT Article DE incompressible and compressible flow; factorizable schemes; genuinely multidimensional upwind schemes; optimal multigrid efficiency ID MULTIGRID CONVERGENCE; CONSERVATION-LAWS AB We present an upwind high-resolution factorizable (UHF) discrete scheme for the compressible Euler equations. The scheme approximates equations in their general conservative form and is related to the family of genuinely multidimensional upwind schemes developed previously and demonstrated to have good shockcapturing capabilities. A unique property of this scheme is that in addition to the aforementioned features it is also factorizable, i.e., it allows to distinguish between full-potential and advection factors at the discrete level. The latter property facilitates the construction of optimally efficient multigrid solvers. This is done through a relaxation procedure that utilizes the factorizability property. (C) 2001 Published by Elsevier Science B.V on behalf of IMACS. C1 Soreq NRC, IL-81800 Yavne, Israel. NASA, ICASE, Langley Res Ctr, Hampton, VA 23681 USA. RP Sidilkover, D (reprint author), Soreq NRC, IL-81800 Yavne, Israel. NR 23 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9274 J9 APPL NUMER MATH JI Appl. Numer. Math. PD JUN PY 2002 VL 41 IS 3 BP 423 EP 436 AR PII S0168-9274(01)00123-4 DI 10.1016/S0168-9274(01)00123-4 PG 14 WC Mathematics, Applied SC Mathematics GA 558CB UT WOS:000175946500004 ER PT J AU Des Marais, DJ Harwit, MO Jucks, KW Kasting, JF Lin, DNC Lunine, JI Schneider, J Seager, S Traub, WA Woolf, NJ AF Des Marais, DJ Harwit, MO Jucks, KW Kasting, JF Lin, DNC Lunine, JI Schneider, J Seager, S Traub, WA Woolf, NJ TI Remote sensing of planetary properties and biosignatures on extrasolar terrestrial planets SO ASTROBIOLOGY LA English DT Article DE spectroscopy; biosignatures; extrasolar planets; Terrestrial Planet Finder; Darwin; habitable planets ID HABITABLE ZONES; LIFE; EVOLUTION; EARTH; ATMOSPHERE; SIGNATURE; SEARCH; VENUS; STARS AB The major goals of NASA's Terrestrial Planet Finder (TPF) and the European Space Agency's Darwin missions are to detect terrestrial-sized extrasolar planets directly and to seek spectroscopic evidence of habitable conditions and life. Here we recommend wavelength ranges and spectral features for these missions. We assess known spectroscopic molecular band features of Earth, Venus, and Mars in the context of putative extrasolar analogs. The preferred wavelength ranges are 7-25 mum in the mid-IR and 0.5 to similar to1.1 mum in the visible to near-IR. Detection of O-2 or its photolytic product O-3 merits highest priority. Liquid H2O is not a bioindicator; but it is, considered essential to life. Substantial CO2 indicates an atmosphere and oxidation state typical of a terrestrial planet. Abundant CH4 might require a biological source, yet abundant CH4 also can arise from a crust and upper mantle more reduced than that of Earth: The range of characteristics of extrasolar rocky planets might far exceed that of the Solar System. Planetary size and mass are very important indicators of habitability and can be estimated in the mid-IR and potentially also in the visible to near-IR. Additional spectroscopic features merit study, for example, features created by other biosignature compounds in the atmosphere or on the surface and features due to Rayleigh scattering. In summary, we find that both the mid-IR and the visible to near-IR wavelength ranges offer valuable information regarding biosignatures and planetary properties; therefore both merit serious scientific consideration for TPF and Darwin. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Cornell Univ, Ithaca, NY USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Penn State Univ, State Coll, PA USA. Univ Calif Santa Cruz, Santa Cruz, CA 95064 USA. Univ Arizona, Tucson, AZ USA. Observ Paris, Meudon, France. Inst Adv Study, Princeton, NJ 08540 USA. RP Des Marais, DJ (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 44 TC 246 Z9 248 U1 8 U2 51 PU MARY ANN LIEBERT INC PUBL PI LARCHMONT PA 2 MADISON AVENUE, LARCHMONT, NY 10538 USA SN 1531-1074 J9 ASTROBIOLOGY JI Astrobiology PD SUM PY 2002 VL 2 IS 2 BP 153 EP 181 DI 10.1089/15311070260192246 PG 29 WC Astronomy & Astrophysics; Biology; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics; Geology GA 671KJ UT WOS:000182463700002 PM 12469366 ER PT J AU Kuznetz, LH Gan, DC AF Kuznetz, LH Gan, DC TI On the existence and stability of liquid water on the surface of Mars today SO ASTROBIOLOGY LA English DT Article DE Mars; triple point; evaporation; phase diagram; heat transfer; mass transfer AB The recent discovery of high concentrations of hydrogen just below the surface of Mars' polar regions by Mars Odyssey has enlivened the debate about past or present life on Mars. The prevailing assumption prior to the discovery was that the liquid water essential for its existence is absent. That assumption was based largely on the calculation of heat and mass transfer coefficients or theoretical climate models. This research uses an experimental approach to determine the feasibility of liquid water under martian conditions, setting the stage for a more empirical approach to the question of life on Mars. Experiments were conducted in three parts: Liquid water's existence was confirmed by droplets observed under martian conditions in part 1; the evolution of frost melting on the surface of various rocks under martian conditions was observed in part 2; and the evaporation rate of water in Petri dishes under Mars-like conditions was determined and compared with the theoretical predictions of various investigators in part 3. The results led to the conclusion that liquid water can be stable for extended periods of time on the martian surface under present-day conditions. C1 Univ Calif Berkeley, Dept Earth & Planetary Sci, Berkeley, CA 94720 USA. RP Kuznetz, LH (reprint author), NASA, Lyndon B Johnson Space Ctr, Natl Space Biomed Res Inst, Mail Code SK, Houston, TX 77058 USA. NR 14 TC 18 Z9 18 U1 1 U2 3 PU MARY ANN LIEBERT INC PUBL PI LARCHMONT PA 2 MADISON AVENUE, LARCHMONT, NY 10538 USA SN 1531-1074 J9 ASTROBIOLOGY JI Astrobiology PD SUM PY 2002 VL 2 IS 2 BP 183 EP 195 DI 10.1089/15311070260192255 PG 13 WC Astronomy & Astrophysics; Biology; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics; Geology GA 671KJ UT WOS:000182463700003 PM 12469367 ER PT J AU Hutchings, JB Frenette, D Hanisch, R Mo, J Dumont, PJ Redding, DC Neff, SG AF Hutchings, JB Frenette, D Hanisch, R Mo, J Dumont, PJ Redding, DC Neff, SG TI Imaging of z not similar to 2 QSO host galaxies with the Hubble Space Telescope SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : high-redshift; quasars : general ID QUASI-STELLAR OBJECTS; RADIO-QUIET QUASARS; IMAGES; Z=2.3; LOUD AB We report on deep imaging in two filters with the planetary camera of the Hubble Space Telescope of five QSOs at redshift of similar to2, with a range of optical and radio luminosity. The observations included a suite of point-spread function (PSF) observations that were used to construct new PSF models, described elsewhere by Dumont et al. The new PSF models were used to remove the QSO nucleus from the images. We find that the host galaxies have resolved flux of the order of 10% of the QSO nuclei and are generally luminous and blue, indicating active star formation. While most have clearly irregular morphologies, the bulk of the flux can be modeled approximately by an R-1/4 law. However, all host galaxies also have an additional approximately exponential luminosity pro le beyond a radius of about 0."8, as also seen in ground-based data with larger telescopes. The QSOs all have a number of nearby faint blue companions that may be young galaxies at the QSO redshift. We discuss implications for evolution of the host galaxies, their spheroidal populations, and central black holes. C1 Natl Res Council Canada, Herzberg Inst Astrophys, Victoria, BC V8X 4M6, Canada. Space Telescope Sci Inst, Baltimore, MD 21218 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Hutchings, JB (reprint author), Natl Res Council Canada, Herzberg Inst Astrophys, 5071 W Saanich Rd, Victoria, BC V8X 4M6, Canada. NR 23 TC 32 Z9 32 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD JUN PY 2002 VL 123 IS 6 BP 2936 EP 2944 DI 10.1086/340472 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 556BW UT WOS:000175830300004 ER PT J AU Miller, NA Ledlow, MJ Owen, FN Hill, JM AF Miller, NA Ledlow, MJ Owen, FN Hill, JM TI Redshifts for a sample of radio-selected poor clusters SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : clusters : general; galaxies : distances and redshifts ID X-RAY OBSERVATIONS; 20-CM VLA SURVEY; ABELL CLUSTERS; RICH CLUSTERS; SURFACE PHOTOMETRY; SNAPSHOT SURVEY; SKY SURVEY; GALAXIES; CATALOG; SUBSTRUCTURE AB Multifiber optical spectroscopy has been performed on galaxies in the vicinity of strong, nearby radio galaxies. These radio galaxies were selected from the 3CR and B2 catalogs based on their exclusion from the Abell catalog, which is puzzling given the hypothesis that an external medium is required to confine the radio plasma of such galaxies. Velocities derived from the spectra were used to confirm the existence of groups and poor clusters in the fields of most of the radio galaxies. We find that all radio galaxies with classical Fanaroff-Riley type I morphologies prove to reside in clusters, whereas the other radio galaxies often appear to be recent galaxy-galaxy mergers in regions of low galaxy density. These findings confirm the earlier result that the existence of extended X-ray emission combined with a statistical excess of neighboring galaxies can be used to identify poor clusters associated with radio galaxies. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. AURA Inc, GEmini Observ So Operat Ctr, La Serena, Chile. Natl Radio Astron Observ, Socorro, NM 87801 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. RP Miller, NA (reprint author), NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Code 681, Greenbelt, MD 20771 USA. NR 59 TC 35 Z9 35 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD JUN PY 2002 VL 123 IS 6 BP 3018 EP 3040 DI 10.1086/340694 PG 23 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 556BW UT WOS:000175830300009 ER PT J AU Pittard, JM Stevens, IR Williams, PM Pollock, AMT Skinner, SL Corcoran, MF Moffat, AFJ AF Pittard, JM Stevens, IR Williams, PM Pollock, AMT Skinner, SL Corcoran, MF Moffat, AFJ TI High-resolution X-ray imaging of the colliding wind shock in WR 147 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars : binaries : general; stars : early-type; stars : imaging; stars : individual : WR 147; stars : Wolf-Rayet; X-rays : stars ID O-TYPE STARS; SYSTEM WR-147; RADIO-EMISSION; STELLAR WINDS; BINARIES; SIMULATIONS; COMPANIONS; COLLISION; SPECTRUM; MODEL AB We analyze new high-resolution Chandra X-ray images of the Wolf-Rayet binary system WR147. This system contains a WN8 star with an early-type companion located 0.6" to its north, and is the only known early-type binary with a separation on the sky large enough for the wind-wind collision between the stars to currently be resolved at X-ray energies. The 5 ksec Chandra HRC-I image provides the first direct evidence for spatially extended X-ray emission in an early-type binary system. The X-ray emission peaks close to the position of the radio bow shock and north of the WN8 star. A deeper X-ray image is needed to accurately determine the degree of spatial extension, to exactly align the X-ray and optical/radio frames, and to determine whether part of the detected X-ray emission arises in the individual stellar winds. Simulated X-ray images of the wind-wind collision have a FWHM consistent with the data, and maximum likelihood fits suggest that a deeper observation may also constrain the inclination and wind momentum ratio of this system. However, as the WR wind dominates the colliding wind X-ray emission it appears unlikely that (M) over dot and v(infinityOB) can be separately determined from X-ray observations. We also note an inconsistency between numerical and analytical estimates of the X-ray luminosity ratio of the stronger and weaker wind components, and conclude that the analytical results are in error. C1 Univ Leeds, Dept Phys & Astron, Leeds LS2 9JT, W Yorkshire, England. Univ Birmingham, Dept Phys & Astron, Birmingham B15 2TT, W Midlands, England. Univ Edinburgh, Royal Observ, Astron Inst, Edinburgh EH9 3HJ, Midlothian, Scotland. Comp & Sci Co Ltd, Sheffield S10 3GS, S Yorkshire, England. Univ Colorado, UCB 389, CASA, Boulder, CO 80309 USA. Univ Space Res Assoc, Lanham, MD 20706 USA. Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Univ Montreal, Dept Phys, Montreal, PQ H3C 3J7, Canada. Observ Du Mont Megant, Montreal, PQ, Canada. RP Pittard, JM (reprint author), Univ Leeds, Dept Phys & Astron, Woodhouse Lane, Leeds LS2 9JT, W Yorkshire, England. OI Pittard, Julian/0000-0003-2244-5070 NR 48 TC 31 Z9 31 U1 0 U2 0 PU E D P SCIENCES PI LES ULIS CEDEXA PA 7, AVE DU HOGGAR, PARC D ACTIVITES COURTABOEUF, BP 112, F-91944 LES ULIS CEDEXA, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JUN PY 2002 VL 388 IS 1 BP 335 EP 345 DI 10.1051/0004-6361:20020465 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 557GX UT WOS:000175901700036 ER PT J AU Prinja, RK Massa, D Fullerton, AW AF Prinja, RK Massa, D Fullerton, AW TI Wind variability of B supergiants - IV. A survey of IU E time-series data of 11 B0 to B3 stars SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars : early-type; stars : mass-loss; ultraviolet : stars ID SHORT-TERM VARIABILITY; SOUTHERN OB STARS; STELLAR-WIND; MEGA CAMPAIGN; ZETA-PUPPIS; ULTRAVIOLET-ABSORPTION; DEPENDENT STRUCTURE; RESONANCE LINES; SUPER-GIANTS; HOT STARS AB We present the most suitable data sets available in the International Ultraviolet Explorer (IUE) archive for the study of time-dependent stellar winds in early B supergiants. The UV line profile variability in 11 B0 to B3 stars is analysed, compared and discussed, based on 16 separate data sets comprising over 600 homogeneously reduced high-resolution spectrograms. The targets include "normal" stars with moderate rotation rates and examples of rapid rotators. A gallery of grey-scale images (dynamic spectra) is presented, which demonstrates the richness and range of wind variability and highlights different structures in the winds of these stars. This work emphasises the suitability of B supergiants for wind studies, under-pinned by the fact that they exhibit unsaturated wind lines for a wide range of ionization. The wind activity of B supergiants is substantial and has highly varied characteristics. The variability evident in individual stars is classified and described in terms of discrete absorption components, spontaneous absorption, bowed structures, recurrence, and ionization variability and stratification. Similar structures can occur in stars of different fundamental parameters, but also different structures may occur in the same star at a given epoch. We discuss the physical phenomena that may be associated with the spectral signatures. The diversity of wind patterns evident likely reflects the role of stellar rotation and viewing angle in determining the observational characteristics of azimuthally extended structure rooted at the stellar surface. In addition, SEI line-synthesis modelling of the UV wind lines is used to provide further information about the state of the winds in our program stars. Typically the range, implied by the line profile variability, in the product of mass-loss rate and ion fraction ((M) over dot q(i)) is a factor of similar to1.5, when integrated between 0.2 and 0.9 v(infinity); it can however be several times larger over localised velocity regions. At a given effective temperature the mean relative ion ratios can differ by a factor of 5. The general excess in predicted (forward-scattered) emission in the low velocity regime is discussed in terms of structured outflows. Mean ion fractions are estimated over the B0 to B1 spectral classes, and trends in the ionic ratios as a function of wind velocity are described. The low values obtained for the ion fractions of UV resonance lines may reflect the role of clumping in the wind. C1 UCL, Dept Phys & Astron, London WC1E 6BT, England. NASA, Goddard Space Flight Ctr, Raytheon ITSS, Greenbelt, MD 20771 USA. Univ Victoria, Dept Phys & Astron, Victoria, BC V8W 3P6, Canada. Johns Hopkins Univ, Dept Phys & Astron, Ctr Astrophys Sci, Baltimore, MD 21218 USA. RP Prinja, RK (reprint author), UCL, Dept Phys & Astron, Gower St, London WC1E 6BT, England. EM rkp@star.ucl.ac.uk NR 56 TC 39 Z9 39 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JUN PY 2002 VL 388 IS 2 BP 587 EP 608 DI 10.1051/0004-6361:20020503 PG 22 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 560UP UT WOS:000176100000030 ER PT J AU Neiner, C Hubert, AM Floquet, M Jankov, S Henrichs, HF Foing, B Oliveira, J Orlando, S Abbott, J Baldry, IK Bedding, TR Cami, J Cao, H Catala, C Cheng, KP de Souza, AD Janot-Pacheco, E Hao, JX Kaper, L Kaufer, A Leister, NV Neff, JE O'Toole, SJ Schafer, D Smartt, SJ Stahl, O Telting, J Tubbesing, S Zorec, J AF Neiner, C Hubert, AM Floquet, M Jankov, S Henrichs, HF Foing, B Oliveira, J Orlando, S Abbott, J Baldry, IK Bedding, TR Cami, J Cao, H Catala, C Cheng, KP de Souza, AD Janot-Pacheco, E Hao, JX Kaper, L Kaufer, A Leister, NV Neff, JE O'Toole, SJ Schafer, D Smartt, SJ Stahl, O Telting, J Tubbesing, S Zorec, J TI Non-radial pulsation, rotation and outburst in the Be star omega Orionis from the MuSiCoS 1998 campaign SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars : emission line, Be; stars : early-type; stars : individual : omega Ori; stars : oscillations; stars : activity; line : profiles ID LINE-PROFILE VARIATIONS; HERBIG AE/BE STARS; CIRCUMSTELLAR ACTIVITY; MU-CENTAURI; MASS-LOSS; ZETA-OPHIUCHI; TIME-SERIES; STELLAR; EMISSION; VARIABILITY AB omega Ori (HD37490, HR1934) is a Be star known to have presented variations. In order to investigate the nature and origin of its short-term and mid-term variability, a study is performed of several spectral lines (Halpha, Hdelta, HeI 4471, 4713, 4921, 5876, 6678, CII 4267, 6578, 6583, Mg II 4481, Si III 4553 and Si II 6347), based on 249 high signal-to-noise high-resolution spectra taken with 8 telescopes over 22 consecutive nights during the MuSiCoS (Multi SIte COntinuous Spectroscopy) campaign in November-December 1998. The stellar parameters are revisited and the projected rotational velocity (v sin i = 179 km s(-1)) is redetermined using several methods. With the MuSiCoS 98 dataset, a time series analysis of line-profile variations (LPVs) is performed using the Restricted Local Cleanest (RLC) algorithm and a least squares method. The behaviour of the velocity of the centroid of the lines, the equivalent widths and the apparent vsini for several lines, as well as Violet and Red components of photospheric lines affected by emission (red He i lines, Si II 6347, CII 6578, 6583) are analyzed. The non-radial pulsation (NRP) model is examined using phase diagrams and the Fourier-Doppler Imaging (FDI) method. The LPVs are consistent with a NRP mode with l = 2 or 3, \m\ = 2 with frequency 1.03 cd(-1). It is shown that an emission line outburst occurred in the middle of the campaign. Two scenarios are proposed to explain the behaviour of a dense cloud, temporarily orbiting around the star with a frequency 0.46 c d(-1), in relation to the outburst. C1 Univ Paris Meudon, CNRS, GEPI FRE 2459, Paris, France. Univ Amsterdam, Sterrenkundig Inst Anton Pannekoek, NL-1012 WX Amsterdam, Netherlands. Observ Cote Azur, CNRS, UMR 6528, FRESNEL, Nice, France. Astron Observ Beograd, Belgrade, Serbia Monteneg. Estec, Dept Space Sci, ESA Solar Syst Div, Noordwijk, Netherlands. Keele Univ, Dept Phys, Keele, Staffs, England. Osservatorio Astron Palermo GS Vaiana, Palermo, Italy. UCL, Dept Phys & Astron, London WC1E 6BT, England. Univ Sydney, Sch Phys, Sydney, NSW 2006, Australia. Beijing Astron Observ, Beijing, Peoples R China. Observ Paris, LESIA, Paris, France. Calif State Univ Fullerton, Fullerton, CA 92634 USA. Univ Sao Paulo, Inst Astron & Geofis, BR-05508 Sao Paulo, Brazil. European So Observ, Santiago 19, Chile. Coll Charleston, Charleston, SC 29401 USA. W Liberty State Coll, W Liberty, WV USA. Heidelberg Konighstuhl, Landessternwarte, Heidelberg, Germany. Univ Cambridge, Astron Inst, Cambridge CB2 1TN, England. George C Marshall Space Flight Ctr, Huntsville, AL USA. IAP, Paris, France. RP Neiner, C (reprint author), Univ Paris Meudon, CNRS, GEPI FRE 2459, Paris, France. EM Coralie.Neiner@obspm.fr NR 70 TC 31 Z9 32 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JUN PY 2002 VL 388 IS 3 BP 899 EP 916 DI 10.1051/0004-6361:20020522 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 566RD UT WOS:000176441300014 ER PT J AU Netterfield, CB Ade, PAR Bock, JJ Bond, JR Borrill, J Boscaleri, A Coble, K Contaldi, CR Crill, BP de Bernardis, P Farese, P Ganga, K Giacometti, M Hivon, E Hristov, VV Iacoangeli, A Jaffe, AH Jones, WC Lange, AE Martinis, L Masi, S Mason, P Mauskopf, PD Melchiorri, A Montroy, T Pascale, E Piacentini, F Pogosyan, D Pongetti, F Prunet, S Romeo, G Ruhl, JE Scaramuzzi, F AF Netterfield, CB Ade, PAR Bock, JJ Bond, JR Borrill, J Boscaleri, A Coble, K Contaldi, CR Crill, BP de Bernardis, P Farese, P Ganga, K Giacometti, M Hivon, E Hristov, VV Iacoangeli, A Jaffe, AH Jones, WC Lange, AE Martinis, L Masi, S Mason, P Mauskopf, PD Melchiorri, A Montroy, T Pascale, E Piacentini, F Pogosyan, D Pongetti, F Prunet, S Romeo, G Ruhl, JE Scaramuzzi, F TI A measurement by BOOMERANG of multiple peaks in the angular power spectrum of the cosmic microwave background SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic microwave background; cosmology : observations ID GALACTIC DUST EMISSION; RADIATION; FLUCTUATIONS; UNIVERSE; MAPS; ANISOTROPIES; FOREGROUNDS; SUPERNOVAE AB This paper presents a measurement of the angular power spectrum of the cosmic microwave background from l = 75 to l = 1025 (similar to10' to 2.degrees4) from a combined analysis of four 150 GHz channels in the BOOMERANG experiment. The spectrum contains multiple peaks and minima, as predicted by standard adiabatic inflationary models in which the primordial plasma undergoes acoustic oscillations. These results, in concert with other types of cosmological measurements and theoretical models, significantly constrain the values of Omega(tot), Omega(b)h(2), Omega(c)h(2), and n(s). C1 Univ Toronto, Dept Phys, Toronto, ON M5S 3H8, Canada. Univ London Queen Mary & Westfield Coll, London E1 4NS, England. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Toronto, Canadian Inst Theoret Astrophys, Toronto, ON M5S 3H8, Canada. Univ Calif Berkeley, Lawrence Berkeley Lab, Natl Energy Res Sci Comp Ctr, Berkeley, CA 94720 USA. CNR, IROE, I-50127 Florence, Italy. Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. CALTECH, Div Phys Math & Astron, Pasadena, CA 91125 USA. Univ Roma La Sapienza, Dipartimento Fis, I-00185 Rome, Italy. CALTECH, Ctr Infrared Proc & Anal, Pasadena, CA 91125 USA. Univ Calif Berkeley, Dept Astron, Space Sci Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Ctr Particle Astrophys, Berkeley, CA 94720 USA. Cardiff Univ, Dept Phys & Astron, Cardiff CF24 3YB, S Glam, Wales. Univ Oxford, Nucl & Astrophys Lab, Oxford OX 3RH, England. Ist Nazl Geofis, I-00143 Rome, Italy. Univ Toronto, Dept Astron & Astrophys, Toronto, ON M5S 3H8, Canada. RP Netterfield, CB (reprint author), Univ Toronto, Dept Phys, 60 St George St, Toronto, ON M5S 3H8, Canada. RI Jaffe, Andrew/D-3526-2009; OI Masi, Silvia/0000-0001-5105-1439; de Bernardis, Paolo/0000-0001-6547-6446; ROMEO, Giovanni/0000-0002-5535-7803; Melchiorri, Alessandro/0000-0001-5326-6003; Piacentini, Francesco/0000-0002-5444-9327; Hivon, Eric/0000-0003-1880-2733 NR 35 TC 676 Z9 680 U1 1 U2 7 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 1 PY 2002 VL 571 IS 2 BP 604 EP 614 DI 10.1086/340118 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 556CB UT WOS:000175830800004 ER PT J AU Giebels, B Bloom, ED Focke, W Godfrey, G Madejski, G Reilly, KT Parkinson, PMS Shabad, G Bandyopadhyay, RM Fritz, GG Hertz, P Kowalski, MP Lovellette, MN Ray, PS Wolff, MT Wood, KS Yentis, DJ AF Giebels, B Bloom, ED Focke, W Godfrey, G Madejski, G Reilly, KT Parkinson, PMS Shabad, G Bandyopadhyay, RM Fritz, GG Hertz, P Kowalski, MP Lovellette, MN Ray, PS Wolff, MT Wood, KS Yentis, DJ TI Observation of X-ray variability in the BL Lacertae object 1ES 1959+65 SO ASTROPHYSICAL JOURNAL LA English DT Article DE BL Lacertae objects : individual (1ES 1959+65) X-rays : galaxies ID SPACE-TELESCOPE OBSERVATIONS; SPECTRAL VARIABILITY; LAC OBJECTS; M87 JET; EMISSION; MARKARIAN-421; CONSTRAINTS; BLAZARS; PKS-2155-304; SYNCHROTRON AB This paper reports X-ray spectral observations of a relatively nearby (z = 0.048) BL Lac object 1ES 1959+65, which is a potential TeV emitter. The observations include 31 short pointings made by the Unconventional Stellar Aspect ( USA) experiment on board the Advanced Research and Global Observation Satellite (ARGOS), and 17 pointings by the Proportional Counter Array (PCA) on board the Rossi X-Ray Timing Explorer ( RXTE). Most of these observations were spaced by less than 1 day. 1ES 1959+65 was detected by the ARGOS USA detector in the range 1-16 keV, and by the PCA in the 2-16 keV range but at different times. During the closely spaced RXTE observations beginning on 2000 July 28, the ending of one are and the start of another are visible, associated with spectral changes, where the photon index Gamma ranges between similar to1.4 and similar to1.7, and the spectrum is harder when the source is brighter. This implies that 1ES 1959+ 65 is an X-ray selected BL Lac type (XBL) blazar, with the X-ray emission likely to originate via the synchrotron process. The USA observations reveal another are that peaked on 2000 November 14 and doubled the flux within a few days, again associated with spectral changes of the same form. The spectral variability correlated with the flux and timing characteristics of this object that are similar to those of other nearby BL Lac objects and suggest relativistic beaming with a Doppler factor delta greater than or equal to1.6 and magnetic fields on the order of a few milligauss. We also suggest that the steady component of the X-ray emission present in this object as well as in other XBLs may be due to the large-scale relativistic jet ( such as measured by Chandra in many radio-loud active galactic nuclei) but pointing very closely to our line of sight. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. USN, Res Lab, EO Hulburt Ctr Space Res, Washington, DC 20375 USA. NASA, Div Space Sci, Ames Res Ctr, Moffett Field, CA 94305 USA. RP Giebels, B (reprint author), Ecole Polytech, Lab Leprince Ringuet, F-91128 Palaiseau, France. OI Ray, Paul/0000-0002-5297-5278 NR 48 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 JUN 1 PY 2002 VL 571 IS 2 BP 763 EP 770 DI 10.1086/340065 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 556CB UT WOS:000175830800015 ER PT J AU Ueda, Y Yamaoka, K Sanchez-Fernandez, C Dhawan, V Chaty, S Grove, JE McCollough, M Castro-Tirado, AJ Mirabel, F Kohno, K Feroci, M Casella, P Trushkin, SA Castaneda, H Rodriguez, J Durouchoux, P Ebisawa, K Kotani, T Swank, J Inoue, H AF Ueda, Y Yamaoka, K Sanchez-Fernandez, C Dhawan, V Chaty, S Grove, JE McCollough, M Castro-Tirado, AJ Mirabel, F Kohno, K Feroci, M Casella, P Trushkin, SA Castaneda, H Rodriguez, J Durouchoux, P Ebisawa, K Kotani, T Swank, J Inoue, H TI Study of the largest multiwavelength campaign of the microquasar GRS 1915+105 SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; black hole physics; infrared : stars; radio continuum : stars; stars : individual (GRS 1915+105); X-rays : individual ( GRS 1915+105) X-rays : stars ID SUPERLUMINAL SOURCE GRS-1915+105; BLACK-HOLE CANDIDATES; RAY TIMING EXPLORER; X-RAY; RELATIVISTIC JETS; INFRARED FLARES; RADIO-EMISSION; PERFORMANCE; OUTBURST; GALAXY AB We present the results from a multiwavelength campaign of GRS 1915+105 performed from 2000 April 16 to April 25. This is one of the largest coordinated set of observations ever performed for this source, covering the wide energy band in radio (13.3-0.3 cm), near-infrared (J, H, and K bands), X-rays, and gamma rays (from 1 keV to 10 MeV). During the campaign GRS 1915+105 was predominantly in the plateau (or low/hard) state but sometimes showed soft X-ray oscillations: before April 20.3, rapid, quasi-periodic (similar or equal to45 minutes) flare-dip cycles were observed. In the spectral energy distribution in the plateau state, optically thick synchrotron emission and Comptonization is dominant in the radio and X- to gamma-ray bands, respectively. The small luminosity in the radio band relative to that in X-rays indicates that GRS 1915+105 falls in the regime of "radio-quiet" microquasars. In three epochs we detected faint flares in the radio or infrared bands with amplitudes of 10-20 mJy. The radio flares observed on April 17 shows frequency-dependent peak delay, consistent with an expansion of synchrotron-emitting region starting at the transition from the hard-dip to the soft-flare states in X-rays. On the other hand, infrared flares on April 20 appear to follow (or precede) the beginning of X-ray oscillations with an inconstant time delay of similar or equal to5-30 minutes. This implies that the infrared-emitting region is located far from the black hole by greater than or similar to10(13) cm, while its size is less than or similar to10(12) cm constrained from the time variability. We find a good correlation between the quasi-steady flux level in the near-infrared band and in the X-ray band. From this we estimate that the reprocessing of X-rays, probably occurring in the outer parts of the accretion disk, accounts for about 20%-30% of the observed K magnitude in the plateau state. The OSSE spectrum in the 0.05-10 MeV band is represented by a single power law with a photon index of 3.1 extending to similar to1 MeV with no cutoff. We can model the combined GIS-PCA-HEXTE spectra covering 1 200 keV by a sum of the multicolor disk model, a broken power law modified with a high-energy cutoff, and a reflection component. The power-law slope above similar to30 keV is found to be very similar between different states in spite of large flux variations in soft X- rays, implying that the electron energy distribution is not affected by the change of the state in the accretion disk. C1 Inst Space & Astronaut Sci, Sagamihara, Kanagawa 2298510, Japan. RIKEN, Inst Phys & Chem Res, Wako, Saitama 35101, Japan. INTA, LAEFF, Madrid, Spain. Natl Radio Astron Observ, Charlottesville, VA 22903 USA. Open Univ, Dept Phys & Astron, Milton Keynes, Bucks, England. USN, Res Lab, Washington, DC 20375 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. CSIC, IAA, Granada, Spain. Serv Astrophys, Saclay, France. Consejo Nacl Invest Cient & Tecn, IAFE, RA-1033 Buenos Aires, DF, Argentina. NAO, Nobeyama Radio Observ, Nagano, Japan. Univ Tokyo, Inst Astron, Tokyo 113, Japan. CNR, Ist Astrofis Spaziale, I-00185 Rome, Italy. SAO, St Petersburg, Russia. Observ Astron Nacl Mexico, Mexico City, DF, Mexico. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Ueda, Y (reprint author), Inst Space & Astronaut Sci, Sagamihara, Kanagawa 2298510, Japan. RI Swank, Jean/F-2693-2012; OI Casella, Piergiorgio/0000-0002-0752-3301; Feroci, Marco/0000-0002-7617-3421; Castro-Tirado, A. J./0000-0003-2999-3563; Rodriguez, Jerome/0000-0002-4151-4468; Chaty, Sylvain/0000-0002-5769-8601 NR 73 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 JUN 1 PY 2002 VL 571 IS 2 BP 918 EP 935 DI 10.1086/340061 PN 1 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 556CB UT WOS:000175830800029 ER PT J AU Strachan, L Suleiman, R Panasyuk, AV Biesecker, DA Kohl, JL AF Strachan, L Suleiman, R Panasyuk, AV Biesecker, DA Kohl, JL TI Empirical densities, kinetic temperatures, and outflow velocities in the equatorial streamer belt at solar minimum SO ASTROPHYSICAL JOURNAL LA English DT Article DE solar wind; Sun : corona; Sun : UV radiation; techniques : spectroscopic ID ULTRAVIOLET CORONAGRAPH SPECTROMETER; WHOLE-SUN-MONTH; MAGNETIC-FIELD; SOURCE REGIONS; WIND; MODEL; SLOW; ACCELERATION; UVCS/SOHO; ORIGINS AB We use combined Ultraviolet Coronagraph Spectrometer and Large Angle Spectroscopic Coronagraph data to determine the O5+ outflow velocities as a function of height along the axis of an equatorial streamer at solar minimum and as a function of latitude (at 2.3 R-circle dot from Sun center). The results show that outflow increases rather abruptly in the region between 3.6 and 4.1 R-circle dot near the streamer cusp and gradually increases to similar to90 km s(-1) at similar to5 R-circle dot in the streamer stalk beyond the cusp. The latitudinal variation at 2.3 R-circle dot shows that there is no outflow (within the measurement uncertainties) in the center of the streamer, called the core, and that a steep increase in outflow occurs just beyond the streamer legs, where the O VI gimel1032 intensity relative to H I gimel1216 (Lyalpha) is higher than in the core. Velocity variations in both height and latitude show that the transitions from no measurable outflow to positive outflow are relatively sharp and thus can be used to infer the location of the transition from closed to open field lines in streamer magnetic field topologies. Such information, including the densities and kinetic temperatures derived from the observations, provides hard constraints for realistic theoretical models of streamers and the source regions of the slow solar wind. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. NASA, Goddard Space Flight Ctr, Emergent Informat Technol Inc, Greenbelt, MD 20771 USA. RP Strachan, L (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 38 TC 105 Z9 110 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 1 PY 2002 VL 571 IS 2 BP 1008 EP 1014 DI 10.1086/339984 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 556CB UT WOS:000175830800036 ER PT J AU Burgasser, AJ Marley, MS Ackerman, AS Saumon, D Lodders, K Dahn, CC Harris, HC Kirkpatrick, JD AF Burgasser, AJ Marley, MS Ackerman, AS Saumon, D Lodders, K Dahn, CC Harris, HC Kirkpatrick, JD TI Evidence of cloud disruption in the L/T dwarf transition SO ASTROPHYSICAL JOURNAL LA English DT Article DE infrared : stars; stars : atmospheres; stars : fundamental parameters; stars : individual (SDSS J1254-0122, 2MASS J0559-1404); stars : low-mass, brown dwarfs ID ALL-SKY SURVEY; BROWN DWARF; SPECTRAL CLASSIFICATION; ATMOSPHERIC CHEMISTRY; GIANT PLANETS; GLIESE 229B; T-DWARFS; VARIABILITY; 2MASS; DISCOVERY AB Clouds of metal-bearing condensates play a critical role in shaping the emergent spectral energy distributions of the coolest classes of low-mass stars and brown dwarfs, L and T dwarfs. Because condensate clouds in planetary atmospheres show distinct horizontal structure, we have explored a model for partly cloudy atmospheres in brown dwarfs. Our model successfully reproduces the colors and magnitudes of both L and T dwarfs for the first time, including the unexpected brightening of the early- and mid-type T dwarfs at the J band, provided that clouds are rapidly removed from the photosphere at T(eff) approximate to 1200 K. The clearing of cloud layers also explains the surprising persistence and strengthening of gaseous FeH bands in early- and mid- type T dwarfs. The breakup of cloud layers is likely driven by convection in the troposphere, analogous to phenomena observed on Jupiter. Our results demonstrate that planetary-like atmospheric dynamics must be considered when examining the evolution of free-floating brown dwarfs. C1 Univ Calif Los Angeles, Div Astron & Astrophys, Los Angeles, CA 90095 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Vanderbilt Univ, Dept Phys & Astron, Nashville, TN 37235 USA. Washington Univ, Dept Earth & Planetary Sci, Planetary Chem Lab, St Louis, MO 63130 USA. USN Observ, Flagstaff, AZ 86002 USA. CALTECH, Ctr Infrared Proc & Anal, Pasadena, CA 91125 USA. RP Burgasser, AJ (reprint author), Univ Calif Los Angeles, Div Astron & Astrophys, 8965 Math Sci Bldg, Los Angeles, CA 90095 USA. EM adam@astro.ucla.edu; mmarley@mail.arc.nasa.gov; ack@sky.arc.nasa.gov; dsaumon@cactus.phy.vanderbilt.edu; lodders@levee.wustl.edu; dahn@nofs.navy.mil; hch@nofs.navy.mil; davy@ipac.caltech.edu RI Ackerman, Andrew/D-4433-2012; Marley, Mark/I-4704-2013 OI Ackerman, Andrew/0000-0003-0254-6253; NR 33 TC 148 Z9 148 U1 1 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 1 PY 2002 VL 571 IS 2 BP L151 EP L154 DI 10.1086/341343 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 556CE UT WOS:000175831100018 ER PT J AU Kuznetsov, S Titarchuk, L AF Kuznetsov, S Titarchuk, L TI Can any "invariants" be revealed in quasi-periodic phenomena observed from scorpius X-1? SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; relativity; stars : individual (Scorpius X-1); stars : neutron ID X-RAY BINARIES; OSCILLATIONS; MODEL AB Using a large number of Rossi X-Ray Timing Explorer observations of Scorpius X-1, we present a detailed investigation of the transition layer and relativistic precession models (TLM and RPM, respectively). These models predict the existence of the invariant quantities: an inclination angle delta of the magnetospheric axis with the normal to the disk for the TLM and a neutron star (NS) mass M-NS for the RPM. Theoretical predictions of both models are tested, and their self-consistency is checked. We establish the following: (1) The inferred d value is 5.degrees56 +/- 0.degrees09. Correlation of the d-values with the horizontal-branch oscillation (HBO) frequency is rather weak. (2) There is a strong correlation between an inferred M-NS and the HBO frequency in the RPM frameworks. (3) We infer M-NS for different assumptions regarding the relations between the HBO frequency nu(HBO) and the nodal frequency nu(nod). We find that the inferred M-NS = 2.7 +/- 0.1 M. cannot be consistent with any equation of state of NS matter. We conclude that the RPM fails to describe the data while the TLM seems to be compatible. C1 Space Res Inst, High Energy Astrophys Dept, Moscow 117997, Russia. George Mason Univ, Ctr Earth Observing & Space Res, Naval Res Lab, Washington, DC 20375 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Kuznetsov, S (reprint author), Space Res Inst, High Energy Astrophys Dept, Profsoyuznaya 84-32, Moscow 117997, Russia. NR 15 TC 2 Z9 2 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 1 PY 2002 VL 571 IS 2 BP L137 EP L141 DI 10.1086/341342 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 556CE UT WOS:000175831100015 ER PT J AU Park, HS Williams, GG Hartmann, DH Lamb, DQ Lee, BC Tucker, DL Klose, S Stecklum, B Henden, A Adelman, J Barthelmy, SD Briggs, JW Brinkmann, J Chen, B Cline, T Csabai, I Gehrels, N Harvanek, M Hennessy, GS Hurley, K Ivezic, Z Kent, S Kleinman, SJ Krzesinski, J Lindsay, K Long, D Nemiroff, R Neilsen, EH Nitta, A Newberg, HJ Newman, PR Perez, D Periera, W Schneider, DP Snedden, SA Stoughton, C Berk, DEV York, D Ziock, K AF Park, HS Williams, GG Hartmann, DH Lamb, DQ Lee, BC Tucker, DL Klose, S Stecklum, B Henden, A Adelman, J Barthelmy, SD Briggs, JW Brinkmann, J Chen, B Cline, T Csabai, I Gehrels, N Harvanek, M Hennessy, GS Hurley, K Ivezic, Z Kent, S Kleinman, SJ Krzesinski, J Lindsay, K Long, D Nemiroff, R Neilsen, EH Nitta, A Newberg, HJ Newman, PR Perez, D Periera, W Schneider, DP Snedden, SA Stoughton, C Berk, DEV York, D Ziock, K TI LOTIS, Super-LOTIS, Sloan Digital Sky Survey, and Tautenburg observations of GRB 010921 SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts ID GAMMA-RAY BURSTS; AFTERGLOW; SYSTEM AB We present multi-instrument optical observations of the High Energy Transient Explorer (HETE-2) and Interplanetary Network error box of GRB 010921. This event was the first gamma-ray burst (GRB) partly localized by HETE-2 that has resulted in the detection of an optical afterglow. In this Letter, we report the earliest known observations of the GRB 010921 field, taken with the 0.11 m Livermore Optical Transient Imaging System (LOTIS) telescope, and the earliest known detection of the GRB 010921 optical afterglow, using the 0.5 m Sloan Digital Sky Survey Photometric Telescope (SDSS PT). Observations with the LOTIS telescope began during a routine sky patrol 52 minutes after the burst. Observations were made with the SDSS PT, the 0.6 m Super-LOTIS telescope, and the 1.34 m Tautenburg Schmidt telescope 21.3, 21.8, and 37.5 hr, respectively, after the GRB. In addition, the host galaxy was observed with the US Naval Observatory Flagstaff Station 1.0 m telescope 56 days after the burst. We find that at later times (t > 1 day after the burst), the optical afterglow exhibited a power-law decline with a slope of alpha = 1.75 +/- 0.28. However, our earliest observations show that this power-law decline cannot have extended to early times (t < 0.035 days). C1 Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Clemson Univ, Dept Phys & Astron, Clemson, SC 29634 USA. Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. Fermilab Natl Accelerator Lab, Expt Astrophys Grp, Batavia, IL 60510 USA. Karl Schwarzschild Observ, Thuringer Landessternwarte Tautenburg, D-07778 Tautenburg, Germany. USN Observ, Univ Space Res Assoc, Flagstaff Stn, Flagstaff, AZ 86002 USA. Univ Chicago, Yerkes Observ, Williams Bay, WI 53191 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Apache Point Observ, Sunspot, NM 88349 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. European Space Agcy Vilspa, XMM Sci Operat Ctr, Madrid 28080, Spain. Eotvos Lorand Univ, Dept Phys Complex Syst, H-1518 Budapest, Hungary. USN Observ, Washington, DC 20392 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Princeton Univ Observ, Princeton, NJ 08544 USA. Cracow Pedag Univ, Mt Suhora Observ, PL-30084 Krakow, Poland. Michigan Technol Univ, Dept Phys, Houghton, MI 49931 USA. Rensselaer Polytech Inst, Dept Phys, Troy, NY 12180 USA. Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA. RP Park, HS (reprint author), Lawrence Livermore Natl Lab, 7000 East Ave, Livermore, CA 94550 USA. RI Gehrels, Neil/D-2971-2012; Barthelmy, Scott/D-2943-2012; Csabai, Istvan/F-2455-2012; OI Csabai, Istvan/0000-0001-9232-9898; Nemiroff, Robert/0000-0002-4505-6599; Tucker, Douglas/0000-0001-7211-5729 NR 21 TC 14 Z9 14 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 JUN 1 PY 2002 VL 571 IS 2 BP L131 EP L135 DI 10.1086/341334 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 556CE UT WOS:000175831100014 ER PT J AU Ricker, G Hurley, K Lamb, D Woosley, S Atteia, JL Kawai, N Vanderspek, R Crew, G Doty, J Villasenor, J Prigozhin, G Monnelly, G Butler, N Matsuoka, M Shirasaki, Y Tamagawa, T Torii, K Sakamoto, T Yoshida, A Fenimore, E Galassi, M Tavenner, T Donaghy, T Graziani, C Boer, M Dezalay, JP Niel, M Olive, JF Vedrenne, G Cline, T Jernigan, JG Levine, A Martel, F Morgan, E Braga, J Manchanda, R Pizzichini, G Takagishi, K Yamauchi, M AF Ricker, G Hurley, K Lamb, D Woosley, S Atteia, JL Kawai, N Vanderspek, R Crew, G Doty, J Villasenor, J Prigozhin, G Monnelly, G Butler, N Matsuoka, M Shirasaki, Y Tamagawa, T Torii, K Sakamoto, T Yoshida, A Fenimore, E Galassi, M Tavenner, T Donaghy, T Graziani, C Boer, M Dezalay, JP Niel, M Olive, JF Vedrenne, G Cline, T Jernigan, JG Levine, A Martel, F Morgan, E Braga, J Manchanda, R Pizzichini, G Takagishi, K Yamauchi, M TI GRB 010921: Localization and observations by the High Energy Transient Explorer satellite SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts ID GAMMA-RAY BURST; DISCOVERY; AFTERGLOW AB On 2001 September 21 at 05:15:50.56 UT, the French Gamma Telescope (FREGATE) on the High Energy Transient Explorer (HETE) detected a bright gamma-ray burst (GRB). The burst was also seen by the X-detector on the Wide-field X-ray Monitor (WXM) instrument and was therefore well localized in the X-direction; however, the burst was outside the fully coded field of view of the WXM Y-detector, and therefore information on the Y-direction of the burst was limited. Cross-correlation of the HETE and Ulysses time histories yielded an Interplanetary Network (IPN) annulus that crosses the HETE error strip at an similar to45degrees angle. The intersection of the HETE error strip and the IPN annulus produces a diamond-shaped error region for the location of the burst having an area of 310 arcmin(2). Based on the FREGATE and WXM light curves, the duration of the burst is characterized by t(90) = 34.2 s in the WXM 4-25 keV energy range, and 23.8 and 21.8 s in the FREGATE 6-40 and 32-400 keV energy ranges, respectively. The fluence of the burst in these same energy ranges is 4.8 x 10(-6), 5.5 x 10(-6), and 11.4 x 10(-6) ergs cm(-2), respectively. Subsequent optical and radio observations by ground-based observers have identified the afterglow of GRB 010921 and determined an apparent redshift of z = 0.450. C1 MIT, Ctr Space Res, Cambridge, MA 02139 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. Univ Calif Santa Cruz, Dept Astron & Astrophys, Santa Cruz, CA 95064 USA. UPS, CNRS, Ctr Etud Spatiale Rayonnements, F-31028 Toulouse 4, France. Tokyo Inst Technol, Fac Sci, Dept Phys, Meguro Ku, Tokyo 1528551, Japan. RIKEN, Inst Phys & Chem Res, Wako, Saitama 3510198, Japan. Natl Space Dev Agcy Japan, Tsukuba Space Ctr, Tsukuba, Ibaraki 3058505, Japan. Japan Sci & Technol Corp, Kawaguchi, Saitama 3320012, Japan. Aoyama Gakuin Univ, Dept Phys, Setagaya Ku, Tokyo 157, Japan. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Inst Nacl Pesquisas Espaciais, BR-12227010 Sao Jose Dos Campos, Brazil. Tata Inst Fundamental Res, Dept Astron & Astrophys, Mumbai 400005, India. CNR, IASF, I-40129 Bologna, Italy. Miyazaki Univ, Fac Engn, Miyazaki 8892192, Japan. RP Ricker, G (reprint author), MIT, Ctr Space Res, 70 Vassar St, Cambridge, MA 02139 USA. OI Boer, Michel/0000-0001-9157-4349 NR 21 TC 20 Z9 21 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 1 PY 2002 VL 571 IS 2 BP L127 EP L130 DI 10.1086/341337 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 556CE UT WOS:000175831100013 ER PT J AU Perlman, ES Horner, DJ Jones, LR Scharf, CA Ebeling, H Wegner, G Malkan, M AF Perlman, ES Horner, DJ Jones, LR Scharf, CA Ebeling, H Wegner, G Malkan, M TI The WARPS Survey. VI. Galaxy cluster and source identifications from phase I SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE surveys; X-rays : galaxies : clusters; X-rays : general ID MEDIUM SENSITIVITY SURVEY; RAY LUMINOSITY FUNCTION; ABELL CLUSTERS; OPTICAL IDENTIFICATIONS; TEMPERATURE RELATION; COOLING FLOWS; MASS FUNCTION; RADIO-SOURCES; DARK-MATTER; VLA SURVEY AB We present in catalog form the optical identifications for objects from the first phase of the Wide Angle ROSAT Pointed Survey ( WARPS). WARPS is a serendipitous survey of relatively deep, pointed ROSAT observations for clusters of galaxies. The X-ray source detection algorithm used by WARPS is Voronoi Tessellation and Percolation (VTP), a technique which is equally sensitive to point sources and extended sources of low surface brightness. WARPS-I is based on the central regions of 86 ROSAT PSPC fields, covering an area of 16.2 square degrees. We describe here the X-ray source screening and optical identification process for WARPS-I, which yielded 34 clusters at 0.06 < z < 0.75. Twenty-two of these clusters form a complete, statistically well-defined sample drawn from 75 of these 86 fields, covering an area of 14.1 square degrees, with a flux limit of F (0.5 x 2.0 keV) = 6.5 x 10(-14) erg cm(-2) s(-1). This sample can be used to study the properties and evolution of the gas, galaxy and dark matter content of clusters and to constrain cosmological parameters. We compare in detail the identification process and findings of WARPS to those from other recently published X-ray surveys for clusters, including RDCS, SHARC-Bright, SHARC-south, and the CfA 160 deg(2) survey. C1 Space Telescope Sci Inst, Baltimore, MD 21218 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Maryland Baltimore Cty, Dept Phys, Baltimore, MD 21250 USA. NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. Univ Birmingham, Sch Phys & Astron, Birmingham B15 2TT, W Midlands, England. Columbia Univ, Columbia Astrophys Lab, New York, NY 10027 USA. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. Dartmouth Coll, Dept Phys & Astron, Wilder Lab 6127, Hanover, NH 03755 USA. Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90024 USA. RP Perlman, ES (reprint author), Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA. OI Perlman, Eric/0000-0002-3099-1664 NR 73 TC 72 Z9 73 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 JUN PY 2002 VL 140 IS 2 BP 265 EP 301 DI 10.1086/339685 PG 37 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 556LG UT WOS:000175850400004 ER PT J AU Walborn, NR Danks, AC Vieira, G Landsman, WB AF Walborn, NR Danks, AC Vieira, G Landsman, WB TI Space Telescope Imaging Spectrograph observations of high-velocity interstellar absorption-line profiles in the Carina Nebula SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE ISM : abundances; ISM : individual (Carina nebula); ISM : kinematics and dynamics; ISM : lines and bands; ISM : structure; ultraviolet : ISM ID ABUNDANCES; CLOUDS AB An atlas of ultraviolet interstellar absorption-line profiles toward four stars in the Carina Nebula is presented. The observations have been made with the Space Telescope Imaging Spectrograph on the Hubble Space Telescope, with a resolving power of 114,000. Low-ionization, high-ionization, and excited-state lines from a wide array of chemical species are included. Extensive measurements of radial velocities, velocity dispersions, and column densities of individual components in these profiles are also given. The unprecedented capabilities of STIS reveal many more velocity components than previously known; most of the high-velocity components in previous observations with the International Ultraviolet Explorer are now resolved into multiple subcomponents, and even higher velocities are seen. The great range of line strengths available permits the detection of the low-velocity components in the weakest lines, and progressively higher velocities in stronger lines ( in which the low-velocity components become completely blended). The weak and high-ionization lines trace global structure in the H II region, while the strong low-ionization lines show intricate high-velocity structure that likely originates relatively near to the O stars observed. The extreme velocities found in the low-ionization lines toward these four stars are 388 and + 127 km s(-1), with 23-26 resolved components in each. Some components in different stars may be related, but many are different in each line of sight. A remarkably well-defined Routly-Spitzer effect is found in this region. Temporal variations toward one star observed twice have already been reported. These measurements will be used in subsequent astrophysical analyses to further constrain the origins of the phenomena. C1 Space Telescope Sci Inst, Baltimore, MD 21218 USA. Emergent IT, Largo, MD 20774 USA. NASA, Sci Syst & Applicat Inc, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Walborn, NR (reprint author), Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA. NR 16 TC 15 Z9 15 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD JUN PY 2002 VL 140 IS 2 BP 407 EP 456 DI 10.1086/339373 PG 50 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 556LG UT WOS:000175850400009 ER PT J AU Khanna, RK Lowenthal, MS Ammon, HL Moore, MH AF Khanna, RK Lowenthal, MS Ammon, HL Moore, MH TI Molecular structure and infrared spectrum of solid amino formate (HCO(2)NH(2)): Relevance to interstellar ices SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE astrochemistry; infrared : ISM; ISM : clouds; ISM : molecules; methods : data analysis; methods : laboratory ID ISOTOPIC-SUBSTITUTION; ABSORPTION FEATURES; BAND; ACID; IDENTIFICATION; HYDROCARBONS; ANALOGS; COMETS; STARS; OCN AB We report the infrared spectrum of the reaction product of isocyanic acid (HNCO) and water (H(2)O) at 20 K. The reaction is catalyzed by hydrochloric acid ( HCl) even at low temperatures. The resulting product is identified to be amino formate (HCO(2)NH(2)). This identification has been achieved by comparison of the IR spectrum of the product with the corresponding spectra of formic acid (HCO(2)H), methyl formate (HCO(2)CH(3)), and formamide (HCONH(2)), all of which have the H-C=O group. The results of ab initio quantum mechanical calculations of the harmonic frequencies and the infrared intensities of the most stable structure containing NH(2)OCHO groups also agree with the laboratory data. Such complex organics may be produced on the cold interstellar grains and on planetary objects by radiation and/or catalytically induced reactions involving simple C-, H-, N-, and O-containing species. C1 Univ Maryland, Dept Chem & Biochem, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Khanna, RK (reprint author), Univ Maryland, Dept Chem & Biochem, College Pk, MD 20742 USA. EM rk13@umail.umd.edu; mslowent@wam.umd.edu; ha3@umail.umd.edu; ummhm@lepvax.gsfc.nasa.gov NR 25 TC 17 Z9 17 U1 0 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 JUN PY 2002 VL 140 IS 2 BP 457 EP 464 DI 10.1086/339709 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 556LG UT WOS:000175850400010 ER PT J AU Charpinet, S Fontaine, G Brassard, P Dorman, B AF Charpinet, S Fontaine, G Brassard, P Dorman, B TI Adiabatic survey of subdwarf B star oscillations. III. Effects of extreme horizontal branch stellar evolution on pulsation modes SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE stars : interiors; stars : oscillations; subdwarfs ID EC-14026 STARS; ULTRAVIOLET-RADIATION; ELLIPTIC GALAXIES; WHITE-DWARFS; POPULATIONS; HOT AB We present the final results of a large, systematic survey of the adiabatic oscillation properties of models of subdwarf B ( sdB) stars. This survey is aimed at providing the minimal theoretical background with which to understand the asteroseismological characteristics of the recently discovered class of pulsating sdB stars (the EC 14026 objects). In this paper, the last of a series of three, we consider the effects of stellar evolution on the pulsation eigenmodes of sdB star models. We specifically analyze the adiabatic properties of 149 equilibrium models culled from seven distinct extreme horizontal branch evolutionary sequences. Those have been chosen in order to span fully the region of parameter space where real sdB stars are found. We primarily focus on the evolution of the pulsation periods (P) and the rates of period change (dP/dt), which are both a priori observable quantities. Both the acoustic and gravity branches of stellar oscillations are considered. In light of the results derived in the first two papers of this series, we discuss how the values of P and dP/dt relate to the various structural adjustments that sdB stars undergo during evolution. We find that the acoustic modes react primarily to the secular variations of the surface gravity. In contrast, we identify three main factors that regulate the period evolution of gravity modes: these are the variations brought about by evolution in both the surface gravity and the effective temperature, as well as the onset and growth of a chemical discontinuity between the C-O enriched nucleus and the helium-rich mantle. We also find, as expected from our previous results, that the period evolution of the pulsation modes in sdB stars is further complicated by trapping effects (microtrapping in the case of p-modes) and by avoided crossings between modes. The latter occur preferentially in certain regions of parameter space. We provide our final results in the form of extensive tabular data in the appendices, which, we hope, will be useful in future asteroseismological analyses of EC 14026 stars. C1 Observ Midi Pyrenees, Astrophys Lab, F-31400 Toulouse, France. Univ Montreal, Dept Phys, Montreal, PQ H3C 3J7, Canada. Emergent Informat Technol Inc, Greenbelt, MD 20771 USA. NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Charpinet, S (reprint author), Observ Midi Pyrenees, Astrophys Lab, 14 Ave Edouard Belin, F-31400 Toulouse, France. OI Charpinet, Stephane/0000-0002-6018-6180 NR 36 TC 39 Z9 39 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 JUN PY 2002 VL 140 IS 2 BP 469 EP 561 DI 10.1086/339707 PG 93 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 556LG UT WOS:000175850400012 ER PT J AU Hua, XM Kozlovsky, B Lingenfelter, RE Ramaty, R Stupp, A AF Hua, XM Kozlovsky, B Lingenfelter, RE Ramaty, R Stupp, A TI Angular and energy-dependent neutron emission from solar flare magnetic loops SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE elementary particles; gamma rays : theory; Sun : flares ID GAMMA-RAY EMISSION; PRODUCTION CROSS-SECTIONS; ALPHA-PARTICLE BOMBARDMENT; 1982 JUNE 3; MEV PROTONS; ACCELERATED PARTICLES; 256-MEV PROTONS; SPECTRA; SCATTERING; COLLISIONS AB We have developed new neutron production kinematics and thoroughly updated the neutron production cross sections, and we have included ion pitch-angle scattering and magnetic mirroring in our Monte Carlo simulation programs, to make new calculations of anisotropic neutron emission produced in the solar are magnetic loop models. The anisotropy in these models arises from the combined effects of converging magnetic field lines and a rapidly increasing ambient density in the portion of the loop below the chromosphere corona transition. We have carried out new calculations of the depth, time, angle, and energy dependences of the neutron production, the angle distributions and energy spectra of the escaping neutrons, and the energy spectrum of the surviving neutrons at the distance 1 AU from the Sun. These new calculations will now allow much more reliable and detailed analyses of the various solar are neutron spectral observations. C1 Emergent IT Inc, Upper Marlboro, MD 20774 USA. Tel Aviv Univ, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. Univ Calif San Diego, Ctr Astrophys & Space Sci, La Jolla, CA 92093 USA. NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Tel Aviv Univ, Dept Phys, IL-69978 Tel Aviv, Israel. RP Hua, XM (reprint author), Emergent IT Inc, Upper Marlboro, MD 20774 USA. EM xhua@eos.hitc.com; benz@wise1.tau.ac.il; rlingenfelter@ucsd.edu; stupp@wise1.tau.ac.il NR 88 TC 53 Z9 54 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0067-0049 EI 1538-4365 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD JUN PY 2002 VL 140 IS 2 BP 563 EP 579 DI 10.1086/339372 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 556LG UT WOS:000175850400013 ER PT J AU Davis, SS AF Davis, SS TI A note on conservation laws for Keplerian flows SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE hydrodynamics; methods : analytical ID PROTOPLANETARY NEBULA; FINITE-DIFFERENCE; DYNAMICS; DISKS AB The straightforward use of numerical conservation laws in non-Cartesian coordinates for flows with strong gravitational/centrifugal forces may induce significant errors. The numerical error when computing a conservation law driven by a gravitational body force is examined and traced to an incompatible finite-differencing sequence similar to that found in applications involving rectilinear flows. An alternate form of the conservation law is presented and illustrated by computing shock wave motion in a model protoplanetary disk using a high-order finite-difference method. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP NASA, Ames Res Ctr, MS 245-3, Moffett Field, CA 94035 USA. EM sdavis@mail.arc.nasa.gov NR 18 TC 1 Z9 1 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0067-0049 EI 1538-4365 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD JUN PY 2002 VL 140 IS 2 BP 581 EP 588 DI 10.1086/339406 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 556LG UT WOS:000175850400014 ER PT J AU Brown, GV Beiersdorfer, P Liedahl, DA Widmann, K Kahn, SM Clothiaux, EJ AF Brown, GV Beiersdorfer, P Liedahl, DA Widmann, K Kahn, SM Clothiaux, EJ TI Laboratory measurements and identification of the Fe XVIII-XXIV L-shell X-ray line emission SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE atomic data; line : identification; stars : coronae; Sun : corona; Sun : X-rays, gamma rays; X-rays : general ID BEAM ION-TRAP; SOLAR-FLARE; GRATING SPECTROMETER; SPECTRA; SPECTROSCOPY; CAPELLA; PLASMAS AB A comprehensive survey of Deltan greater than or equal to 1 iron L-shell X-ray line emission is presented. We have used the electron beam ion trap EBIT-II at the Lawrence Livermore National Laboratory and equipped with at crystal spectrometers to measure the wavelengths of over 150 features between 10.6 and 18 Angstrom. We present wavelengths, line identifications, and relative intensities of all of the significant Deltan greater than or equal to 1 L-shell line emission from Fe xvIII- XXIV at electron densities of similar to10(12) cm(-3) resulting from direct electron impact excitation from the ground state followed by radiative cascades. This data set includes 2-3 times as many lines as are found in current standard line lists. C1 Lawrence Livermore Natl Lab, Dept Phys & Adv Technol, Livermore, CA 94551 USA. Columbia Univ, Dept Phys, New York, NY 10027 USA. Columbia Univ, Columbia Astrophys Lab, New York, NY 10027 USA. Auburn Univ, Dept Phys, Auburn, AL 36849 USA. RP Brown, GV (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20770 USA. NR 49 TC 72 Z9 73 U1 1 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD JUN PY 2002 VL 140 IS 2 BP 589 EP 607 DI 10.1086/339374 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 556LG UT WOS:000175850400015 ER PT J AU Tao, G Chen, SH Joshi, SM AF Tao, G Chen, SH Joshi, SM TI An adaptive control scheme for systems with unknown actuator failures SO AUTOMATICA LA English DT Article DE actuator failure; adaptive control; plant-model output matching; state feedback; output tracking ID FAULT-DIAGNOSIS AB A state feedback output tracking adaptive control scheme is developed for plants with actuator failures characterized by the failure pattern that some inputs are stuck at some unknown fixed values at unknown time instants. New controller parametrization and adaptive law are developed under some relaxed system conditions. All closed-loop signals are bounded and the plant output tracks a given reference output asymptotically, despite the uncertainties in actuator failures and plant parameters. Simulation results verify the desired adaptive control system performance in the presence of actuator failures. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 Univ Virginia, Dept Elect & Comp Engn, Charlottesville, VA 22903 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Tao, G (reprint author), Univ Virginia, Dept Elect & Comp Engn, Charlottesville, VA 22903 USA. EM gt9s@virginia.edu; sc3ec@virginia.edu; s.m.joshi@larc.nasa.gov NR 13 TC 74 Z9 78 U1 1 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0005-1098 J9 AUTOMATICA JI Automatica PD JUN PY 2002 VL 38 IS 6 BP 1027 EP 1034 AR PII S0005-1098(02)00018-3 DI 10.1016/S0005-1098(02)00018-3 PG 8 WC Automation & Control Systems; Engineering, Electrical & Electronic SC Automation & Control Systems; Engineering GA 548QZ UT WOS:000175401700011 ER PT J AU Martin, DS South, DA Wood, ML Bungo, MW Meck, JV AF Martin, DS South, DA Wood, ML Bungo, MW Meck, JV TI Comparison of echocardiographic changes after short- and long-duration spaceflight SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article DE spaceflight; deconditioning; echocardiography ID ORTHOSTATIC INTOLERANCE; SPACE-FLIGHT; ASTRONAUTS; PRESSURE; HUMANS AB Background: Previous echocardiographic studies of astronauts before and after short-duration (4-17 d) missions have demonstrated a decrease in resting left ventricular stroke volume, but maintained ejection fraction (EF) and cardiac output. Similar studies before and after long-duration (129-144 d) spaceflight have been rare and their overall results equivocal. Methods: Echocardiographic measurements (M-mode, 2-D, and Doppler) were obtained from short-duration (n = 13) and long-duration (n = 4) crewmembers to evaluate cardiac chamber sizes and function. Results: Compared with short-duration astronauts, long-duration crewmembers had decreases in EF (+6 +/- 0.02 vs. -10.15 +/- 0.03%, p = 0.005) and percent fractional shortening (+7 +/- 0.03 vs. -11 +/- 0.07%, p = 0.015), and an increase in left ventricular end systolic volume (-12 +/- 0.06 vs. +39 +/- 0.24%, p = 0.011). Conclusions: These data suggest a reduction in cardiac function that relates to mission duration. As the changes in BP and circulating blood volume are reported to be similar after short- and long-duration flights, the smaller EF after longer spaceflights may be due to a decrease in cardiac function rather than altered blood volume. C1 Wyle Labs, Houston, TX USA. Univ Texas, Med Branch, Galveston, TX 77550 USA. NASA, Johnson Space Ctr, Cardiovasc Lab, Houston, TX USA. RP Meck, JV (reprint author), NASA, Lyndon B Johnson Space Ctr, Life Sci Res Lab, Mail Code SK23, Houston, TX 77058 USA. NR 19 TC 26 Z9 35 U1 2 U2 4 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 USA SN 0095-6562 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD JUN PY 2002 VL 73 IS 6 BP 532 EP 536 PG 5 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA 555CX UT WOS:000175776700002 PM 12056667 ER PT J AU Lindsay, JF AF Lindsay, JF TI Supersequences, superbasins, supercontinents - evidence from the Neoproterozoic-Early Palaeozoic basins of central Australia SO BASIN RESEARCH LA English DT Review ID AMADEUS BASIN; WESTERN-AUSTRALIA; TECTONIC EVOLUTION; PALAEOPROTEROZOIC BRYAH; DEPOSITIONAL CONTROLS; NORTHERN AUSTRALIA; MANTLE CONVECTION; CAPRICORN OROGEN; PACIFIC-OCEAN; BILLION YEARS AB Neoproterozoic sedimentary basins cover a large area of central Australia. They rest upon rigid continental crust that varies from c. 40-50 km in thickness. Whilst the crust was in part formed during the Archaean and early Palaeoproterozoic, its final assembly occurred at approximately 1.1 Ga as the Neoproterozoic supercontinent, Rodinia, came into being. The assembly process left an indelible imprint on the region producing a strong crustal fabric in the form of a series of north dipping thrusts that pervade much of the thick craton and extend almost to the Moho. Following a period of stability (1.1-0.8 Ga), a large area of central Australia, in excess of 2.5 x 10(6) km(2) , began to subside in synchroneity. This major event was due to mantle instability resulting from the insulating effect of Rodinia. Initially, beginning c. 900 Ma, a rising superplume uplifted much of central Australia leading to peneplanation of the uplifted region and the generation of large volumes of sand-sized clastic materials. Ultimately, the decline of the superplume led to thermal recovery and the development of a sag basin (beginning at c. 800 Ma), which in turn resulted in the redistribution of the clastic sediments and the development of a vast sand sheet at the base of the Neoproterozoic succession. The superbasin generated by the thermal recovery was short lived (c. 20 M.y.) but, in conjunction with the crustal fabric developed during supercontinent assembly, it set the stage for further long-term basin development that extended for half a billion years well into the Late Palaeozoic. Following the sag phase at least five major tectonic episodes influenced the central Australian region. Compressional tectonics reactivated earlier thrust faults that had remained dormant within the crust, disrupting the superbasin, causing uplift of basement blocks and breaking the superbasin into the four basins now identified within the central Australian Neoproterozoic succession (Officer, Amadeus, Ngalia and Georgina Basin). These subsequent tectonic events produced the distinctive foreland architecture associated with the basins and were perhaps the trigger for the Neoproterozoic ice ages. The reactivated basins became asymmetric with major thrust faults along one margin paralleled by deep narrow troughs that formed the main depocentres for the remaining life of the basins. The final major tectonic event to influence the central Australian basins, the Alice Springs Orogeny, effectively terminated sedimentation in the region in the Late Palaeozoic (c. 290 Ma). Of the six tectonic episodes recorded in the basinal succession only one provides evidence of extension, suggesting the breakup of east Gondwana at the end of the Rodinian supercontinent cycle may have occurred at close to the time of the Precambrian-Cambrian boundary. The central Australian basins are thus the products of events surrounding the assembly and dispersal of Rodinia. C1 NASA, Lyndon B Johnson Space Ctr, JSC Astrobiol Inst, Houston, TX 77058 USA. RP Lindsay, JF (reprint author), NASA, Lyndon B Johnson Space Ctr, JSC Astrobiol Inst, SA-13, Houston, TX 77058 USA. NR 120 TC 31 Z9 33 U1 1 U2 6 PU BLACKWELL PUBLISHING LTD PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DG, OXON, ENGLAND SN 0950-091X J9 BASIN RES JI Basin Res. PD JUN PY 2002 VL 14 IS 2 BP 207 EP 223 DI 10.1046/j.1365-2117.2002.00170.x PG 17 WC Geosciences, Multidisciplinary SC Geology GA 561FJ UT WOS:000176129300007 ER PT J AU Boehm, MT Starr, DOC Verlinde, J Lee, S AF Boehm, MT Starr, DOC Verlinde, J Lee, S TI The tropical convection - Tropopause cirrus connection SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article; Proceedings Paper CT 11th Conference on Cloud Physics/11th Conference on Atmospheric Radiation CY JUN 03-07, 2002 CL OGDEN, UTAH C1 NASA, GSFC, Greenbelt, MD 20771 USA. RP Boehm, MT (reprint author), NASA, GSFC, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD JUN PY 2002 VL 83 IS 6 BP 843 EP 843 PG 1 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 570LU UT WOS:000176660400007 ER PT J AU Goody, R Anderson, J Karl, T Miller, RB North, G Simpson, J Stephens, G Washington, W AF Goody, R Anderson, J Karl, T Miller, RB North, G Simpson, J Stephens, G Washington, W TI Why monitor the climate? SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID SYSTEM C1 Harvard Univ, Cambridge, MA 02138 USA. NOAA, NCDC, Asheville, NC USA. Columbia Univ, CIESIN, New York, NY 10032 USA. Texas A&M Univ, College Stn, TX 77843 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Colorado State Univ, Ft Collins, CO 80523 USA. NCAR, Boulder, CO USA. RP Goody, R (reprint author), 101 Cumloden Dr, Falmouth, MA 02540 USA. RI North, Gerald/G-1019-2011 NR 13 TC 26 Z9 31 U1 2 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD JUN PY 2002 VL 83 IS 6 BP 873 EP 878 DI 10.1175/1520-0477(2002)083<0873:WWSMTC>2.3.CO;2 PG 6 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 570LU UT WOS:000176660400015 ER PT J AU Gourrion, J Vandemark, D Bailey, S Chapron, B AF Gourrion, J Vandemark, D Bailey, S Chapron, B TI Investigation of C-band altimeter cross section dependence on wind speed and sea state SO CANADIAN JOURNAL OF REMOTE SENSING LA English DT Article ID SURFACE AB Wind and wave impacts on C-band altimeter backscatter data are presented using data collected from the TOPEX/POSEIDON platform. The compilation of a large global data set of TOPEX observations collocated with NASA scatterometer (NSCAT) wind speed estimates is used to propose an algorithm for wind speed retrieval using both cross section and significant wave height observations. Evidence of sea state impact on radar backscatter is further analyzed through comparison with National Oceanographic Data Center (NODC) buoy spectral wave measurements. For wind speeds above 6 m(.)s(-1) and global mean sea state conditions, altimeter and buoy-derived slope variance estimates exhibit high correlation in their wind speed and sea state dependencies. Results suggest that the C-band instrument may be used to derive new data on the degree of development of the sea state. C1 IFREMER, Dept Oceanog Spatiale, F-29280 Plouzane, France. NASA, Goddard Space Flight Ctr, Wallops Isl, VA 23337 USA. RP Gourrion, J (reprint author), IFREMER, Dept Oceanog Spatiale, BP 70, F-29280 Plouzane, France. RI Chapron, Bertrand/O-6527-2015 NR 15 TC 10 Z9 10 U1 0 U2 1 PU CANADIAN AERONAUTICS SPACE INST PI OTTAWA PA 1685 RUSSELL RD, UNIT 1-R, OTTAWA, ON K1G 0N1, CANADA SN 0703-8992 J9 CAN J REMOTE SENS JI Can. J. Remote Sens. PD JUN PY 2002 VL 28 IS 3 BP 484 EP 489 PG 6 WC Remote Sensing SC Remote Sensing GA 573PK UT WOS:000176839900016 ER PT J AU Grewe, V Reithmeier, C Shindell, DT AF Grewe, V Reithmeier, C Shindell, DT TI Dynamic-chemical coupling of the upper troposphere and lower stratosphere region SO CHEMOSPHERE LA English DT Article DE UT/LS coupling; upper troposphere NOx and ozone; lightning NOx ID GENERAL-CIRCULATION MODEL; NOX EMISSIONS; CHEMISTRY; OZONE; SIMULATION; EXCHANGE; LAYER AB The importance of the interaction between chemistry and dynamics in the upper troposphere and lower stratosphere for chemical species like ozone is investigated using two chemistry-climate models and a Lagrangian trajectory model. Air parcels from the upper troposphere, i.e. regions of lightning and aircraft emissions, are able to be transported into the lowermost stratosphere (LMS). Trajectory calculations suggest that the main transport pathway runs via the inter tropical convergence zone, across the tropical tropopause and then to higher latitudes, i.e. into the LMS. NOx from aircraft emissions at mid-latitudes are unlikely to perturb the LMS since they are washed-out while still in the troposphere. In contrast, NOx from tropical lightning has the chance to accumulate in the LMS. Because of the longer residence times of NOx in the LMS, compared to the upper troposphere, this excess NOx from lightning has the potential to form ozone in the LMS, which then is transported back to the troposphere at mid-latitudes. In the models, around 10% of the ozone concentration and 50% of the NOx concentration in the northern hemisphere LMS is produced by lightning NOx. At least 5% of the ozone concentration and 35% the NOx concentration at 150 hPa at midlatitudes originates from tropical lightning in the climate-chemistry simulations. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 Deutsch Zentrum Luft & Raumfahrt EV DLR, Inst Phys Atmosphare, D-82234 Wessling, Germany. Columbia Univ, Ctr Climate Syst Res, New York, NY 10025 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Grewe, V (reprint author), Deutsch Zentrum Luft & Raumfahrt EV DLR, Inst Phys Atmosphare, Oberpfaffenhofen, D-82234 Wessling, Germany. RI Shindell, Drew/D-4636-2012; Grewe, Volker/A-6147-2011 OI Grewe, Volker/0000-0002-8012-6783 NR 32 TC 12 Z9 12 U1 1 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0045-6535 J9 CHEMOSPHERE JI Chemosphere PD JUN PY 2002 VL 47 IS 8 BP 851 EP 861 AR PII S0045-6535(02)00038-3 DI 10.1016/S0045-6535(02)00038-3 PG 11 WC Environmental Sciences SC Environmental Sciences & Ecology GA 560MW UT WOS:000176086700006 PM 12079080 ER PT J AU Smith, MD Davis-Street, JE Nillen, JL Smith, SM AF Smith, MD Davis-Street, JE Nillen, JL Smith, SM TI Effects of long term storage on i-STAT (R) (EC)6+cartridge shelf-life. SO CLINICAL CHEMISTRY LA English DT Meeting Abstract C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Enterprise Advisory Serv Inc, Houston, TX USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER ASSOC CLINICAL CHEMISTRY PI WASHINGTON PA 2101 L STREET NW, SUITE 202, WASHINGTON, DC 20037-1526 USA SN 0009-9147 J9 CLIN CHEM JI Clin. Chem. PD JUN PY 2002 VL 48 IS 6 SU S MA F67 BP A193 EP A194 PN 2 PG 2 WC Medical Laboratory Technology SC Medical Laboratory Technology GA 559QZ UT WOS:000176038000627 ER PT J AU Kulkarni, AD Yamauchi, K Hales, NW Ramesh, V Ramesh, GT Sundaresan, A Andrassy, RJ Pellis, NR AF Kulkarni, AD Yamauchi, K Hales, NW Ramesh, V Ramesh, GT Sundaresan, A Andrassy, RJ Pellis, NR TI Nutrition beyond nutrition: plausibility of immunotrophic nutrition for space travel SO CLINICAL NUTRITION LA English DT Article DE nucleotide; nutrition; immunity; space travel ID DIETARY NUCLEOTIDE RESTRICTION; PROTEIN-KINASE-C; IMMUNE FUNCTION; SPACEFLIGHT; SUSPENSION; RESPONSES; MICE; COUNTERMEASURES; MICROGRAVITY; ACTIVATION AB Background and aims: Microgravity has adverse effects on the immune system. We examined the effects of supplemental dietary nucleotides on immune function in ground-based in vivo anti-orthostatic tail-suspended (AOS) mice and in vitro (bioreactor-BIO) analogs of microgravity. Methods: BALB/c mice were divided into the following three groups: group housed, single isolation, and AOS. Mice were fed either control chow or chow supplemented with RNA or uracil. Immune function was assessed by in vivo popliteal lymph node proliferation (PLN), in vitro PHA-stimulated proliferation of splenocytes and cytokine production. 1310 splenocytes were cultured in vitro with/without PHA, a nucleoside-nucleotide mixture (NS/NT) or uridine. The cell proliferation and scanning electron microscopic examination for cells were carried out. Results: PLN response was significantly suppressed in AOS mice (P < 0.05) and was restored by RNA and uracil diets. Splenocytes from AOS mice had decreased phytohemagglutinin (PHA)-stimulated proliferation, decreased IL-2 and IFN-gamma cytokine levels (P < 0.05). These responses were restored by RNA and uracil diets. In BIO cultures, PHA response was suppressed significantly, and uridine and NS/NT restored the proliferative responses. Scanning electron microscopic analysis of cells cultured in 1310 revealed cells with pinched, distorted and eroded membranes. Nucleotide supplementation especially uridine restored normal activated cell surface appearance and ruffling. Conclusion: In the microgravity analog environment of AOS and 810, supplemental nucleotides and especially uracil/uridine have up-regulating and immunoprotective effects with potential as a countermeasure to the observed immune dysfunction in true microgravity. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 Univ Texas, Sch Med, Dept Surg, Hlth Sci Ctr, Houston, TX 77030 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Wyle Labs, Houston, TX USA. Texas So Univ, Dept Biol, Houston, TX 77004 USA. RP Kulkarni, AD (reprint author), Univ Texas, Sch Med, Dept Surg, Hlth Sci Ctr, 6431 Fannin,MSB Suite 4-164, Houston, TX 77030 USA. NR 34 TC 6 Z9 7 U1 1 U2 3 PU CHURCHILL LIVINGSTONE PI EDINBURGH PA JOURNAL PRODUCTION DEPT, ROBERT STEVENSON HOUSE, 1-3 BAXTERS PLACE, LEITH WALK, EDINBURGH EH1 3AF, MIDLOTHIAN, SCOTLAND SN 0261-5614 J9 CLIN NUTR JI Clin. Nutr. PD JUN PY 2002 VL 21 IS 3 BP 231 EP 238 DI 10.1054/clnu.2002.0539 PG 8 WC Nutrition & Dietetics SC Nutrition & Dietetics GA 581NT UT WOS:000177299300008 PM 12127932 ER PT J AU Kradinov, V Hanauska, J Barut, A Madenci, E Ambur, DR AF Kradinov, V Hanauska, J Barut, A Madenci, E Ambur, DR TI Bolted patch repair of composite panels with a cutout SO COMPOSITE STRUCTURES LA English DT Article DE patch; repair; multiple bolts; composites; cutout AB The present investigation concerns the analysis of bolted patch repairs of flat composite panels by using a complex potential-variational method. The validity of the current analysis predictions is established by comparison against experimental measurements and previous predictions. The experimental investigation used two patch repairs, with different bolt patterns, of a cutout in an aluminum skin under uniaxial loading. The previous predictions were made for a patch-repaired composite skin with 16 bolts under uniaxial loading. The same patch repair configuration is analyzed here under more complex loading conditions and with two bolts missing, leading to a non-symmetric bolt arrangement. Also, the influence of patch geometry and bolt pattern on the effectiveness of the repair is investigated by considering an elliptical cutout in the skin. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 Univ Arizona, Dept Aerosp & Mech Engn, Tucson, AZ 85721 USA. NASA, Langley Res Ctr, Mech & Durabil Branch, Hampton, VA 23665 USA. RP Madenci, E (reprint author), Univ Arizona, Dept Aerosp & Mech Engn, POB 210119, Tucson, AZ 85721 USA. NR 9 TC 3 Z9 6 U1 0 U2 0 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0263-8223 J9 COMPOS STRUCT JI Compos. Struct. PD JUN PY 2002 VL 56 IS 4 BP 423 EP 444 AR PII S0263-8223(02)00027-2 DI 10.1016/S0263-8223(02)00027-2 PG 22 WC Materials Science, Composites SC Materials Science GA 567UE UT WOS:000176503100009 ER PT J AU Harik, VM AF Harik, VM TI Mechanics of carbon nanotubes: applicability of the continuum-beam models SO COMPUTATIONAL MATERIALS SCIENCE LA English DT Article DE nanostructures; nanotubes; mechanical properties; scaling analysis; laws of similitude; buckling ID COMPRESSION AB Ranges of validity for the continuum-beam models, the length-scale effects and continuum assumptions are analyzed in the framework of scaling analysis of NT structure. Two coupled criteria for the applicability of the continuum models are presented. Scaling analysis of NT buckling and geometric parameters (e.g,, diameter and length) is carried out to determine the key non-dimensional parameters that control the buckling strains and modes of NT buckling, A model applicability map, which represents two classes of NTs, is constructed in the space of non-dimensional parameters. In an analogy with continuum mechanics, a mechanical law of geometric similitude is presented for two classes of beam-like NTs having different geometries. Expressions for the critical buckling loads and strains are tailored for the distinct groups of NTs and compared with the data provided by the molecular dynamics simulations. Implications for molecular dynamics simulations and the NT-based scanning probes are discussed. (C) 2001 Elsevier Science B.V. All rights reserved. C1 NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. RP Harik, VM (reprint author), NASA, Langley Res Ctr, ICASE, MS 132C, Hampton, VA 23681 USA. NR 13 TC 75 Z9 76 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0927-0256 J9 COMP MATER SCI JI Comput. Mater. Sci. PD JUN PY 2002 VL 24 IS 3 BP 328 EP 342 AR PII S0927-0256(01)00255-5 DI 10.1016/S0927-0256(01)00255-5 PG 15 WC Materials Science, Multidisciplinary SC Materials Science GA 578GF UT WOS:000177108500004 ER PT J AU Miller, RL Belz, M Del Castillo, C Trzaska, R AF Miller, RL Belz, M Del Castillo, C Trzaska, R TI Determining CDOM absorption spectra in diverse coastal environments using a multiple pathlength, liquid core waveguide system SO CONTINENTAL SHELF RESEARCH LA English DT Article DE absorption; absorbance; coastal optics; CDOM; liquid core waveguide; spectrophotometers ID DISSOLVED ORGANIC-MATTER; WAVE-GUIDE; ABSORBENCY SPECTROSCOPY; YELLOW SUBSTANCE; OCEAN; SEA; CHLOROPHYLL; NITRITE; NITRATE; WATERS AB We evaluated the accuracy, sensitivity and precision of a multiple pathlength, liquid core waveguide (MPLCW) system for measuring colored dissolved organic matter (CDOM) absorption in the UV-visible spectral range (370-700 nm). The MPLCW has four optical paths (2.0, 9.8, 49.3, and 204 cm) coupled to a single Teflon AF sample cell. Water samples were obtained from inland, coastal and ocean waters ranging in salinity from 0 to 36 PSU. Reference solutions for the MPLCW were made having a refractive index of the sample. CDOM absorption coefficients, a(CDOM), and the slope of the log-linearized absorption spectra, S, were compared with values obtained using a dual-beam spectrophotometer. Absorption of phenol red secondary standards measured by the MPLCW at 558 nm were highly correlated with spectrophotometer values (r > 0.99) and showed a linear response across all four pathlengths. Values of a(CDOM) measured using the MPLCW were virtually identical to spectrophotometer values over a wide range of concentrations. The dynamic range of a(CDOM) for MPLCW measurements was 0.002-231.5 m(-1). At low CDOM concentrations (a(370) < 0.1 m(-1)) spectrophotometric a(CDOM) were slightly greater than MPLCW values and showed larger fluctuations at longer wavelengths due to limitations in instrument precision. In contrast, MPLCW spectra followed an exponential to 600 nm for all samples. The maximum deviation in replicate MPLCW spectra was <0.001 absorbance units. The portability, sampling, and optical characteristics of a MPLCW system provide significant enhancements for routine CDOM absorption measurements in a broad range of natural waters. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 NASA, Stennis Space Ctr, MS 39529 USA. World Precis Instruments Inc, Sarasota, FL 34240 USA. GB Tech, Stennis Space Ctr, MS 39529 USA. RP Miller, RL (reprint author), NASA, Code MA00 Bldg 1100, Stennis Space Ctr, MS 39529 USA. RI Del Castillo, Carlos/N-2601-2013 NR 25 TC 53 Z9 56 U1 3 U2 15 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0278-4343 J9 CONT SHELF RES JI Cont. Shelf Res. PD JUN PY 2002 VL 22 IS 9 BP 1301 EP 1310 AR PII S0278-4343(02)00009-2 DI 10.1016/S0278-4343(02)00009-2 PG 10 WC Oceanography SC Oceanography GA 563TQ UT WOS:000176272000002 ER PT J AU Ferl, R Wheeler, R Levine, HG Paul, AL AF Ferl, R Wheeler, R Levine, HG Paul, AL TI Plants in space SO CURRENT OPINION IN PLANT BIOLOGY LA English DT Review ID STARCH-DEFICIENT MUTANTS; ALCOHOL-DEHYDROGENASE; GRAVITROPIC RESPONSE; CARBON-DIOXIDE; BRASSICA-RAPA; LIFE-SUPPORT; MICROGRAVITY; ARABIDOPSIS; SPACEFLIGHT; GROWTH AB Virtually all scenarios for the long-term habitation of spacecraft and other extraterrestrial structures involve plants as important parts of the contained environment that would support humans. Recent experiments have identified several effects of spaceflight on plants that will need to be more fully understood before plant-based life support can become a reality. The International Space Station (ISS) is the focus for the newest phase of space-based research, which should solve some of the mysteries of how spaceflight affects plant growth. Research carried out on the ISS and in the proposed terrestrial facility for Advanced Life Support testing will bring the requirements for establishing extraterrestrial plant-based life support systems into clearer focus. C1 Univ Florida, Program Plant Mol & Cellular Biol, Dept Hort Sci, Gainesville, FL 32601 USA. NASA, Biol Sci Branch, Kennedy Space Ctr, FL 32899 USA. Dynam Corp, Kennedy Space Ctr, FL 32899 USA. RP Ferl, R (reprint author), Univ Florida, Program Plant Mol & Cellular Biol, Dept Hort Sci, 1301 Fifield Hall, Gainesville, FL 32601 USA. NR 75 TC 49 Z9 55 U1 2 U2 18 PU CURRENT BIOLOGY LTD PI LONDON PA 84 THEOBALDS RD, LONDON WC1X 8RR, ENGLAND SN 1369-5266 J9 CURR OPIN PLANT BIOL JI Curr. Opin. Plant Biol. PD JUN PY 2002 VL 5 IS 3 BP 258 EP 263 DI 10.1016/S1369-5266(02)00254-6 PG 6 WC Plant Sciences SC Plant Sciences GA 545GD UT WOS:000175208000012 PM 11960745 ER PT J AU Essington, TE Schindler, DE Olson, RJ Kitchell, JF Boggs, C Hilborn, R AF Essington, TE Schindler, DE Olson, RJ Kitchell, JF Boggs, C Hilborn, R TI Alternative fisheries and the predation rate of yellowfin tuna in the Eastern Pacific Ocean SO ECOLOGICAL APPLICATIONS LA English DT Article DE apex predator; bioenergetics; dolphin; ecosystem; fisheries; food webs; longline; predator-prey; purse seine; recruitment; Thunnus albacares; yellowfin tuna ID AGE-STRUCTURED MODEL; THUNNUS-ALBACARES; ECOLOGICAL-SOCIETY; GASTRIC EVACUATION; MARINE ECOSYSTEM; IMPACTS; BIOENERGETICS; CONSERVATION; EQUILIBRIUM; COMMUNITIES AB Apex predators in pelagic ecosystems may play key roles in determining food web structure and ecosystem dynamics. Commercial fisheries can thereby have large effects on pelagic ecosystems by selectively harvesting apex predators. We assessed the potential ecological consequences of fishing due to alternative harvest practices currently employed in the capture of yellowfin tuna (Thunnus albacares) in the eastern Pacific Ocean (EPO). Specifically, we estimated the demand on the prey resources consumed by yellowfin tuna and how this demand is altered by three methods of pure seining and by long-lining. These fishing techniques are contrasted by stark differences in age selectivity; longline and purse seine sets on yellowfin associated with dolphins ("dolphin sets") capture old fish, whereas purse seine sets on free-swimming tuna schools or floating objects ("dolphin-safe sets") capture young yellowfin. Yellowfin tuna predation rates were estimated froth a bioenergetics model coupled with a population model based on natural mortality estimates and age-specific vulnerabilities for each gear type. Maximum equilibrium fishery catch (measured in megagrams per year; 1 Mg = 1 metric ton) was lowest fur dolphin-safe sets and highest for dolphin sets and longline fishing. Moreover, the present combined fishery yield could not be sustained by either of the dolphin-safe sets, but could be sustained with either dolphin sets or long-lining. The predation rate of the yellowfin population was highly sensitive to the magnitude and type of fishing mortality: yellow fin predation rate declined by similar to119 Mg per megagram of floating object set catch, 72 Mg per megagram of school fish set catch. In contrast, predation declined by only 34 Mg and 17 Mg per megagram of dolphin set and longline catch, respectively. When considering all fishing techniques simultaneously in proportion to the present fishery, we estimated that total yellowfin predation is presently only one-third the magnitude expected froth an unfished population. This reduction in predation was unevenly distributed among prey items; the prey of large yellowfin experienced 80% less predation, whereas the prey of small yellowfin experienced only 50% less predation, compared to an unfished population. We conclude that fisheries can have large effects on trophic linkages in pelagic food webs even when fishing rates are sustainable, and that these ecological effects vary considerably for different types of fishing gear and fishing practices. C1 Univ Wisconsin, Ctr Limnol, Madison, WI 53706 USA. Univ Washington, Dept Zool, Seattle, WA 98195 USA. Scripps Inst Oceanog, InterAmer Trop Tuna Commiss, La Jolla, CA 92037 USA. NOAA, Natl Marine Fisheries Serv, SW Fisheries Ctr, Honolulu Lab, Honolulu, HI 96822 USA. Univ Washington, Sch Aquat Sci & Fisheries, Seattle, WA 98195 USA. RP Essington, TE (reprint author), SUNY Stony Brook, Math Sci Res Ctr, Stony Brook, NY 11794 USA. EM Timothy.Essington@sunysb.edu RI Hilborn, Ray/D-6332-2013 NR 57 TC 48 Z9 48 U1 0 U2 20 PU ECOLOGICAL SOC AMER PI WASHINGTON PA 1990 M STREET NW, STE 700, WASHINGTON, DC 20036 USA SN 1051-0761 J9 ECOL APPL JI Ecol. Appl. PD JUN PY 2002 VL 12 IS 3 BP 724 EP 734 PG 11 WC Ecology; Environmental Sciences SC Environmental Sciences & Ecology GA 553UL UT WOS:000175693800015 ER PT J AU Schindler, DE Essington, TE Kitchell, JF Boggs, C Hilborn, R AF Schindler, DE Essington, TE Kitchell, JF Boggs, C Hilborn, R TI Sharks and tunas: Fisheries impacts on predators with contrasting life histories SO ECOLOGICAL APPLICATIONS LA English DT Article DE apex predators; bioenergetics; blue shark vs. yellowfin tuna; exploitation; food web; longline fisheries; marine conservation; Pacific Ocean; predation; Prionace glauca; shark finning; Thunnus albacare ID PRIONACE-GLAUCA; BLUE SHARK; MARINE ECOSYSTEMS; NATURAL MORTALITY; FISH STOCKS; BIOENERGETICS; EFFICIENCY; ABUNDANCE; DOGFISH; GROWTH AB Large-scale pelagic fisheries exploit a diversity of apex predators with a wide range of life history strategies. Exploitation of species with different life history strategies has different population and food web consequences. We explored the changes in predation that result from exploitation of a common species with a slow growth and low fecundity life history strategy (blue shark, Prionace glauca) with those that result from exploitation of a common species with fast growth and high fecundity (yellowfin tuna, Thunnus albacares) in the central Pacific Ocean. Longline fisheries directed toward billfishes and tunas also capture blue sharks as incidental catch. Mortality rates of sharks had been relatively low prior to the recent surge in finning that has resulted in a substantial rise in mortality of adult and subadult sharks in the last decade. We estimated the magnitude of changes in predation by populations of yellowfin tuna and blue sharks in response to longline fisheries that involve shark finning. Bioenergetics models for sharks and tunas were coupled to simple population models that account for changes in size-structure in response to fishery-induced mortality regimes in order to estimate predation responses to changes in fishing intensities. Our analyses demonstrate that blue shark populations are very sensitive to low exploitation rates, while yellowfin tuna populations are extremely robust across a wide range of exploitation rates by longline fisheries. Although predation rates by yellowfin tuna are 4-5 times higher than by blue sharks, longline fisheries have substantially greater effects on shark predation than on yellowfin tuna predation at the food web scale. Expected food web responses will be strongest where the unexploited biomass of long-lived species is high and predation is relatively specialized compared with other apex predators. Our analyses suggest that active management to reduce finning mortality in sharks will play an important role toward minimizing the effects of longline fisheries on the food web structure of the pelagic Pacific Ocean. C1 Univ Washington, Dept Zool, Seattle, WA 98195 USA. Univ Wisconsin, Ctr Limnol, Madison, WI 53706 USA. NOAA, Natl Marine Fisheries Serv, SW Fisheries Ctr, Honolulu Lab, Honolulu, HI 96822 USA. Univ Washington, Sch Aquat Sci & Fisheries, Seattle, WA 98195 USA. RP Schindler, DE (reprint author), Univ Washington, Dept Zool, Box 351800, Seattle, WA 98195 USA. RI Hilborn, Ray/D-6332-2013 NR 66 TC 74 Z9 78 U1 11 U2 72 PU ECOLOGICAL SOC AMER PI WASHINGTON PA 1707 H ST NW, STE 400, WASHINGTON, DC 20006-3915 USA SN 1051-0761 J9 ECOL APPL JI Ecol. Appl. PD JUN PY 2002 VL 12 IS 3 BP 735 EP 748 DI 10.2307/3060985 PG 14 WC Ecology; Environmental Sciences SC Environmental Sciences & Ecology GA 553UL UT WOS:000175693800016 ER PT J AU Elices, M Llorca, J Sayir, A AF Elices, M Llorca, J Sayir, A TI Fracture of high performance fibres SO ENGINEERING FRACTURE MECHANICS LA English DT Editorial Material C1 Univ Politecn Madrid, ETSI Caminos, E-28040 Madrid, Spain. NASA, Glenn Res Ctr, Div Mat, Cleveland, OH 44135 USA. RP Elices, M (reprint author), Univ Politecn Madrid, ETSI Caminos, Ciudad Univ,Prof Aranguren S-N, E-28040 Madrid, Spain. RI Elices, Manuel/F-7703-2016 OI Elices, Manuel/0000-0002-8204-1580 NR 0 TC 0 Z9 0 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 JUN PY 2002 VL 69 IS 9 BP 1005 EP 1005 AR PII S0013-7944(01)00116-3 PG 1 WC Mechanics SC Mechanics GA 558VE UT WOS:000175986800001 ER PT J AU Farmer, SC Sayir, A AF Farmer, SC Sayir, A TI Tensile strength and microstructure of Al2O3-ZrO2 hypo-eutectic fibers SO ENGINEERING FRACTURE MECHANICS LA English DT Article DE strength; modulus; Al2O3; ZrO2; eutectic ID MECHANICAL-PROPERTIES AB Al2O3-ZrO2(Y2O3) eutectic materials possess good fracture strengths and creep resistance. Increased Al2O3 content is one means to further improve creep resistance. The objective of this study is to examine fracture strength of Al2O3-rich (hypoeutectic) compositions at varying Y2O3 contents. Fibers 160-220 mum in diameter with 68 m/o Al2O3 and 1.1-7.6 m/o Y2O3 (30.5 to 16 m/o ZrO2) were directionally solidified at 0.11 mm/s using the laser-heated float-zone process. Defect populations increased in size and severity with higher Y2O3 contents. However, fibers maintained 1 GPa fracture strength in the presence of numerous pores and shrinkage cavities, which extend with crack-like morphology along the fiber axis. Published by Elsevier Science Ltd. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Farmer, SC (reprint author), NASA, Glenn Res Ctr, 21000 Brookpk Rd,M-S 106-5, Cleveland, OH 44135 USA. NR 21 TC 28 Z9 34 U1 0 U2 9 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 JUN PY 2002 VL 69 IS 9 BP 1015 EP 1024 AR PII S0013-7944(01)00118-7 DI 10.1016/S0013-7944(01)00118-7 PG 10 WC Mechanics SC Mechanics GA 558VE UT WOS:000175986800003 ER PT J AU Gonzalez, LJ Maida, JC Miles, EH Rajulu, SL Pandya, AK AF Gonzalez, LJ Maida, JC Miles, EH Rajulu, SL Pandya, AK TI Work and fatigue characteristics of unsuited and suited humans during isolated isokinetic joint motions SO ERGONOMICS LA English DT Article DE joint fatigue; joint strength; task planning; Extra-Vehicular Activity (EVA); Extra-Vehicular Mobility Unit (EMU) AB The effects of a pressurized suit on human performance were investigated. The suit is known as an Extra-Vehicular Mobility Unit (EMU) and is worn by astronauts while working outside their spacecraft in a low earth orbit. Isolated isokinetic joint torques of three female and three male subjects (all experienced users of the suit in IG gravity) were measured while working at 100% and 80% of their maximum voluntary torque (MVT, which is synonymous with maximum voluntary contraction (MVC)). It was found that the average decrease in the total amount of work (the sum of the work in each repetition until fatigue) done when the Subjects were wearing the EMU were 48% and 41% while working at 100% and 80% MVT, respectively. There is a clear relationship between the MVT and the time and amount of work done until fatigue. Here, the time to fatigue is defined as the ending time of the repetition for which the computed work done during that repetition dropped below 50% of the work done during the first repetition. In general the stronger joints took longer to fatigue and did more work than the weaker joints. It was found that the EMU decreases the work output at the wrist and shoulder joints the most, due to the EMU joint geometry. The EMU also decreased the joint range of motion. The average total amount of work done by the test subjects increased by 5.2% (20.4%) for the unsuited (suited) case, when the test subjects decreased the level of effort from 100% to 80% MVT. Also, the average time to fatigue increased by 9.2% (25.6%) for the unsuited (suited) case, when the test subjects decreased the level of effort from 100% to 80% MVT. It was also found that the experimentally measured torque decay could be predicted by a logarithmic equation. The absolute average errors in the predictions were found to be 18.3% and 18.9% for the Unsuited and suited subjects, respectively, when working at 100% MVT, and 22.5% and 18.8% for the unsuited and suited subjects, respectively, when working at 80% MVT. These results could be very useful in the design of future EMU suits and the planning of Extra-Vehicular Activity (EVA) for the future International Space Station assembly operations. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. SPACEHAB Inc, Houston, TX 77058 USA. Wayne State Univ, Dept Elect & Comp Engn, Detroit, MI 48202 USA. Baylor Coll Med, Natl Space Biomed Res Inst, Houston, TX 77030 USA. RP Maida, JC (reprint author), NASA, Lyndon B Johnson Space Ctr, Mail Code C23,2400 NASA Rd 1, Houston, TX 77058 USA. EM jim.maida@jsc.nasa.gov NR 15 TC 6 Z9 6 U1 1 U2 6 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0014-0139 J9 ERGONOMICS JI Ergonomics PD JUN PY 2002 VL 45 IS 7 BP 484 EP 500 DI 10.1080/00140130210139582 PG 17 WC Engineering, Industrial; Ergonomics; Psychology, Applied; Psychology SC Engineering; Psychology GA 571EE UT WOS:000176701200002 PM 12167203 ER PT J AU Liu, HS Kolenkiewicz, R Wade, C AF Liu, HS Kolenkiewicz, R Wade, C TI Orbital noise in the Earth system is a common cause of climate and greenhouse-gas fluctuation SO FLUCTUATION AND NOISE LETTERS LA English DT Article DE orbital signals; frequency noise; climate fluctuation; celestial mechanics; earth system science AB The mismatch between fossil isotopic data and climate models known as the cool-tropic paradox implies that either the data are flawed or we understand very little about the climate models of greenhouse warming. Here we question the validity of the climate models on the scientific background of orbital noise in the Earth system. Our study shows that the insolation pulsation induced by orbital noise is the common cause of climate change and atmospheric concentrations of carbon dioxide and methane. In addition, we find that the intensity of the insolation pulses is dependent on the latitude of the Earth. Thus, orbital noise is the key to understanding the troubling paradox in climate models. 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 hanshou@core2.gsfc.nasa.gov NR 33 TC 1 Z9 1 U1 1 U2 2 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA 5 TOH TUCK LINK, SINGAPORE 596224, SINGAPORE SN 0219-4775 J9 FLUCT NOISE LETT JI Fluct. Noise Lett. PD JUN PY 2002 VL 2 IS 2 BP L101 EP L108 DI 10.1142/S021947750200066X PG 8 WC Mathematics, Interdisciplinary Applications; Physics, Applied SC Mathematics; Physics GA V42ON UT WOS:000202876900004 ER PT J AU Zak, M AF Zak, M TI Quantum evolution as a nonlinear Markov process SO FOUNDATIONS OF PHYSICS LETTERS LA English DT Article DE hidden statistics; quantum evolution; nonlinear Markov process AB Based upon the Madelung version of the Schrodinger equation, quantum evolution in real space is interpreted as a nonlinear Markov process in which the future state depends upon the present state and the present probability distribution. From this viewpoint, the concepts of nonlocality and entanglement are discussed. The concept of hidden statistics is introduced as an alternative way to formulate and interpret quantum formalism as well as to solve the Schrodinger equation. The problem of incompleteness of the Schrodinger description as well as physical meaning of the quantum potential is discussed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Oak Ridge Natl Lab, Ctr Engn Sci Adv Res, Oak Ridge, TN USA. RP Zak, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 3 Z9 3 U1 0 U2 0 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0894-9875 J9 FOUND PHYS LETT JI Found. Phys. Lett. PD JUN PY 2002 VL 15 IS 3 BP 229 EP 243 DI 10.1023/A:1021079403550 PG 15 WC Physics, Multidisciplinary SC Physics GA 574KX UT WOS:000176889700002 ER PT J AU Herd, CDK Borg, LE Jones, JH Papike, JJ AF Herd, CDK Borg, LE Jones, JH Papike, JJ TI Oxygen fugacity and geochemical variations in the martian basalts: Implications for martian basalt petrogenesis and the oxidation state of the upper mantle of Mars SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID OVERLYING SUBDUCTION ZONES; RARE-EARTH ELEMENTS; FE-TI OXIDES; SNC METEORITES; SHERGOTTY METEORITE; MAGMATIC PROCESSES; AQUEOUS ALTERATION; PHASE-EQUILIBRIA; SILICIC MAGMAS; REDOX STATE AB The oxygen fugacity of the Dar al Gani 476 martian basalt is determined to be quartz-fayalite-magnetite (QFM) -2.3 +/- 0.4 through analysis of olivine, low-Ca pyroxene, and Cr-spinel and is in good agreement with revised results from Fe-Ti oxides that yield QFM -2.5 +/- 0.7. This estimate falls within the range of oxygen fugacity for the other martian basalts, QFM -3 to QFM -1. Oxygen fugacity in martian basalts correlates with Sr-87/Sr-86, Nd-143/Nd-144, and La/Yb ratios, indicating that the mantle source of the basalts is reduced and that assimilation of crust-like material controls the oxygen fugacity. This allows constraints to be placed on the oxidation state of the martian mantle and on the nature of assimilated crustal material. The assimilated material may be the product of early and extensive hydrothermal alteration of the martian crust, or it may be amphibole- or phlogopite-bearing basaltic rock within the crust. In either case, water may play a significant role in the oxidation of basaltic magmas on Mars, although it may be secondary to assimilation of ferric iron-rich material. Copyright (C) 2002 Elsevier Science Ltd. C1 Univ New Mexico, Dept Earth & Planetary Sci, Inst Meteorit, Albuquerque, NM 87131 USA. NASA, Lyndon B Johnson Space Ctr, Astromat Res Off, Houston, TX 77058 USA. RP Herd, CDK (reprint author), Lunar & Planetary Inst, 3600 Bay Area Blvd, Houston, TX 77058 USA. EM herd@lpi.usra.edu NR 66 TC 167 Z9 167 U1 0 U2 27 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 EI 1872-9533 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD JUN PY 2002 VL 66 IS 11 BP 2025 EP 2036 DI 10.1016/S0016-7037(02)00828-1 PG 12 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 557UM UT WOS:000175926600011 ER PT J AU Borg, LE Nyquist, LE Wiesmann, H Reese, Y AF Borg, LE Nyquist, LE Wiesmann, H Reese, Y TI Constraints on the petrogenesis of Martian meteorites from the Rb-Sr and Sm-Nd isotopic systematics of the lherzolitic shergottites ALH77005 and LEW88516 SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID UPPER-MANTLE; ALHA77005; MAGMA; MARS; DIFFERENTIATION; CRYSTALLIZATION; PETROGRAPHY; CHRONOLOGY; CHEMISTRY; OLIVINE AB Detailed Rb-Sr and Sm-Nd isotopic analyses have been completed on the lherzolitic shergottites ALH77005 and LEW88516. ALH77005 yields a Rb-Sr age of 185 +/- 11 Ma and a Sm-Nd age of 173 +/- 6 Ma, whereas the Rb-Sr and Sm-Nd ages of LEW88516 are 183 +/- 10 and 166 +/- 16 Ma, respectively. The initial Sr isotopic composition of ALH77005 is 0.71026 +/- 4, and the initial epsilon(Nd) value is + 11.1 +/- 0.2. These values are distinct from those of LEW88516, which has an initial Sr isotopic composition of 0.71052 +/- 4 and an initial epsilon(Nd) value of +8.2 +/- 0.6. Several of the mineral and whole rock leachates lie off the Rb-Sr and Sm-Nd isochrons, indicating that the isotopic systematics of the meteorites have been disturbed. The Sm-Nd isotopic compositions of the leachates appear to be mixtures of primary igneous phosphates and an alteration component with a low Nd-143/Nd-144 ratio that was probably added to the meteorites on Mars. Tie lines between leachate-residue pairs from LEW88516 mineral fractions and whole rocks have nearly identical slopes that correspond to Rb-Sr ages of 90 I Ma. This age may record a major shock event that fractionated Rb/Sr from lattice sites located on mineral grain boundaries. On the other hand, the leachates could contain secondary alteration products, and the parallel slopes of the tie lines could be coincidental. Nearly identical mineral modes, compositions, and ages suggest that these meteorites are very closely related. Nevertheless, their initial Sr and Nd isotopic compositions differ outside analytical uncertainty, requiring derivation from unique sources. Assimilation-fractional-crystallization models indicate that these two lherzolitic meteorites can only be related to a common parental magma, if the assimilant has a Sr/Nd ratio near 1 and a radiogenic Sr isotopic composition. Further constraints placed on the evolved component by the geochemical and isotopic systematics of the shergottite meteorite suite suggest that it (a) formed at similar to4.5 Ga, (b) has a high La/Yb ratio, (c) is an oxidant, and (d) is basaltic in composition or is strongly enriched in incompatible elements. The composition and isotopic systematics of the. evolved component are unlike any evolved lunar or terrestrial igneous rocks. Its unusual geochemical and isotopic characteristics could reflect hydrous alteration of an evolved Martian crustal component or hydrous metasamatism within the Martian mantle. Copyright (C) 2002 Elsevier Science Ltd. C1 Univ New Mexico, Inst Meteorit, Albuquerque, NM 87131 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Lockheed Engn & Sci Co, Houston, TX 77258 USA. RP Borg, LE (reprint author), Univ New Mexico, Inst Meteorit, Albuquerque, NM 87131 USA. NR 54 TC 71 Z9 73 U1 1 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 JUN PY 2002 VL 66 IS 11 BP 2037 EP 2053 DI 10.1016/S0016-7037(02)00835-9 PG 17 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 557UM UT WOS:000175926600012 ER PT J AU Tsurutani, BT Galvan, C Arballo, JK Winterhalter, D Sakurai, R Smith, EJ Buti, B Lakhina, GS Balogh, A AF Tsurutani, BT Galvan, C Arballo, JK Winterhalter, D Sakurai, R Smith, EJ Buti, B Lakhina, GS Balogh, A TI Relationship between discontinuities, magnetic holes, magnetic decreases, and nonlinear Alfven waves: Ulysses observations over the solar poles SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ROTATIONAL DISCONTINUITIES; WIND; FIELD AB [1] Ulysses magnetic field data are used to study magnetic field microstructure over the solar poles. Magnetic holes (MHs) and magnetic decreases (MDs) are found to be located at the phase-steepened edges of nonlinear Alfven waves. The phase-steepened edges (directional discontinuities) occur in time-coincidence with MHs, one edge of an MD, or throughout the whole MD. These MH- and MD-related discontinuities have both rotational and compressive properties, perhaps explaining why many directional discontinuities detected in interplanetary space have non-MHD properties. The dispersive, dissipative and compressive features of nonlinear Alfven waves may be important for the heating of the solar corona. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Natl Phys Lab, New Delhi 110008, India. Indian Inst Geomagnetism, Bombay 400005, Maharashtra, India. Univ London Imperial Coll Sci Technol & Med, Blackett Lab, London SW7 2BZ, England. RP Tsurutani, BT (reprint author), CALTECH, Jet Prop Lab, MS 169-506,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Bruce.Tsurutani@jpl.nasa.gov RI Lakhina, Gurbax /C-9295-2012 NR 18 TC 33 Z9 34 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 1 PY 2002 VL 29 IS 11 AR 1528 DI 10.1029/2001GL013623 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 610MN UT WOS:000178964000032 ER PT J AU Smith, JG Belvin, HL Siochi, EJ Cano, RJ Johnston, NJ AF Smith, JG Belvin, HL Siochi, EJ Cano, RJ Johnston, NJ TI Chemistry and properties of a phenylethynyl-terminated imide blend SO HIGH PERFORMANCE POLYMERS LA English DT Article DE phenylethynyl imide oligomer; high-perfonnance/high-temperature resins; composites; films; 4-phenylethynylphthalic anhydride ID POLYIMIDE OLIGOMERS; COMPOSITE; PENDENT; ADHESIVE; ANHYDRIDES AB As part of an effort to develop a low-volatile, essentially dry, carbon fiber tape from a phenylethynyl-terminated imide for use in heated head automated tow placement, a 70:30 blend of LaRCTM PETI-5 and LaRCTM PETI-IAX was prepared in N-methyl-2-pyrrolidinone by mixing the phenylethynyl-terminated amide acid solutions together. Solutions of the amide acids and the blend were characterized by size exclusion,chromatography after aging at room temperature and at 5degreesC over a 30-day period. Thin films were periodically cast from the solutions, thermally cured, and the tensile properties determined. Unoriented thin-film tensile properties were unaffected by aging conditions over the 30-day period whereas the weight average molecular weights of the phenylethynyl-terminated amide acids decreased. Imide oligomers were prepared from the amide acids, characterized, and thermally cured. A low-volatile tape prepared from prepreg of the 70:30 blend was fabricated into composites by processing in a vacuum press. The thin-film tensile and composite properties of the blend generally followed a rule of mixtures. C1 NASA, Adv Mat & Proc Branch, Langley Res Ctr, Hampton, VA 23681 USA. RP Smith, JG (reprint author), NASA, Adv Mat & Proc Branch, Langley Res Ctr, Hampton, VA 23681 USA. NR 35 TC 3 Z9 3 U1 0 U2 3 PU SAGE PUBLICATIONS LTD PI LONDON PA 6 BONHILL STREET, LONDON EC2A 4PU, ENGLAND SN 0954-0083 J9 HIGH PERFORM POLYM JI High Perform. Polym. PD JUN PY 2002 VL 14 IS 2 BP 209 EP 223 PG 15 WC Polymer Science SC Polymer Science GA 611WF UT WOS:000179040200009 ER PT J AU Smith, JG Thompson, CM Watson, KA Connell, JW AF Smith, JG Thompson, CM Watson, KA Connell, JW TI Poly(arylene ether)s containing phenylphosphine oxide groups SO HIGH PERFORMANCE POLYMERS LA English DT Article DE poly(arylene ether)s; atomic oxygen-resistant polymers; phosphine oxide-containing poly(arylene; ether)s; low-solar-absorptivity poly(arylene ether)s; space environmentally durable poly(arylene ether)s; 2,5dihydroxyphenyldiphenylphosphine oxide ID ATOMIC OXYGEN EXPOSURE AB As part of a NASA program to develop materials for potential future space applications, poly(arylene ether)s containing phenylphosphine oxide groups were prepared and characterized. The polymers were synthesized by the aromatic nucleophilic displacement reaction of two isomeric bisphenols, 2,5-dihydroxyphenyldiphenylphosphine oxide and bis(4-hydroxyphenyl)phenylphosphine oxide, with activated aromatic difluorides in the presence of anhydrous potassium carbonate in N,N-dimethylacetamide at 155degreesC. The polymers exhibited inherent viscosities from 0.35 to 1.00 dL g(-1) and glass transition temperatures from 160 to 249degreesC. Thermogravimetric analyses showed 5% weight loss ranging from 382 to 479degreesC in air and 377 to 505degreesC in nitrogen. Unoriented thin films exhibited tensile strengths, moduli, and break elongations at 23degreesC of 49-94 MPa, 2.3-3.4 GPa, and 6-41%, respectively Limiting oxygen indices from 18-32 were calculated based on polymer char residues at 850degreesC in nitrogen. The polymers exhibited relatively low solar absorptivities ranging from 0.04 to 0.16 and thermal emissivities ranging from 0.48 to 0.63. The chemistry, physical, and mechanical properties of these polymers are presented herein. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Smith, JG (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 20 TC 22 Z9 23 U1 0 U2 3 PU SAGE PUBLICATIONS LTD PI LONDON PA 6 BONHILL STREET, LONDON EC2A 4PU, ENGLAND SN 0954-0083 J9 HIGH PERFORM POLYM JI High Perform. Polym. PD JUN PY 2002 VL 14 IS 2 BP 225 EP 239 PG 15 WC Polymer Science SC Polymer Science GA 611WF UT WOS:000179040200010 ER PT J AU Biesecker, DA Lamy, P St Cyr, OC Llebaria, A Howard, RA AF Biesecker, DA Lamy, P St Cyr, OC Llebaria, A Howard, RA TI Sungrazing comets discovered with the SOHO/LASCO coronagraphs 1996-1998 SO ICARUS LA English DT Article ID LASCO; SOLAR; MISSION; UVCS AB The Kreutz sungrazing family of comets is unique because of its small perihelion distance and because of the large number of known members of this family. SOHO/LASCO coronagraph observations beginning in 1996 have revealed an unprecedented number of Kreutz comets. These new coronagraph observations improve upon earlier observations because of a larger field-of-view, increased image cadence, and better photometric measurements. This paper presents the lightcurves of the 141 Kreutz family comets observed from 1996 through 1998. Throughout this period, the number of family members discovered each year is shown to be constant. None of the comets were detected postperihelion. The lightcurves show distinctive characteristics which reveal much about the properties of the nuclei. It is shown that the individual fragments can be related to one of two "standard candies," which we call Universal Curves. The comets all reach a peak brightness at one of two characteristic distances (both near 12 R-circle dot) and that the comets fragment at another characteristic distance (about 7 R-circle dot). Also, evidence is seen for line emission, which varies with heliocentric distance. (C) 2002 Elsevier Science (USA). C1 NASA, Goddard Space Flight Ctr, Emergent IT Inc, Greenbelt, MD 20771 USA. CNRS, Astron Spatiale Lab, F-13376 Marseille 12, France. Catholic Univ Amer, Washington, DC 20064 USA. CNRS, Astron Spatiale Lab, F-13376 Marseille 12, France. USN, Res Lab, EO Hulburt Ctr Space Res, Washington, DC 20375 USA. RP Biesecker, DA (reprint author), NASA, Goddard Space Flight Ctr, Emergent IT Inc, Greenbelt, MD 20771 USA. NR 17 TC 52 Z9 52 U1 0 U2 3 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD JUN PY 2002 VL 157 IS 2 BP 323 EP 348 DI 10.1006/icar.2002.6827 PG 26 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 568NK UT WOS:000176548300005 ER PT J AU Braak, CJ de Haan, JF Hovenier, JW Travis, LD AF Braak, CJ de Haan, JF Hovenier, JW Travis, LD TI Galileo photopolarimetry of Jupiter at 678.5 nm SO ICARUS LA English DT Article DE Jupiter, atmosphere; photometry; polarimetry; radiative transfer ID POLARIZED-LIGHT; PLANETARY-ATMOSPHERES; MULTIPLE-SCATTERING; AEROSOL PROPERTIES; SATELLITE RETRIEVAL; REFLECTED SUNLIGHT; JOVIAN ATMOSPHERE; PHASE-ANGLE; PHOTOMETRY; VENUS AB Brightness and linear polarization measurements at 678.5 nm for four south-north strips of Jupiter are studied. These measurements were obtained in 1997 by the Galileo photopolarimeter/radiometer. The observed brightness exhibits latitudinal variations consistent with the belt/zone structure of Jupiter. The observed degree of linear polarization is small at low latitudes and increases steeply toward higher latitudes. No clear correlations were observed between the degree of linear polarization and the brightness. The observed direction of polarization changes from approximately parallel to the local scattering plane at low latitudes to perpendicular at higher latitudes. For our studies, we used atmospheric models that include a haze layer above a cloud layer. Parameterized scattering matrices were employed for the haze and cloud particles. On a pixel-wise basis, the haze optical thickness and the single-scattering albedo of the cloud particles were derived from the observed brightness and degree of linear polarization; results were accepted only if they were compatible with the observed direction of polarization. Using atmospheric parameter values obtained from Pioneer 10 and 11 photopolarimetry for the South Tropical Zone and the north component of the South Equatorial Belt, this analysis yielded acceptable results for very few pixels, particularly at small phase angles. However, for almost all pixels, acceptable results were found when the parameterized scattering matrix of the cloud particles was adjusted to produce more negative polarization for single scattering of unpolarized light, especially at large scattering angles, similar to some laboratory measurements of ammonia ice crystals. Using this adjusted model, it was found that the derived latitudinal variation of the single-scattering albedo of the cloud particles is consistent with the belt/zone structure, and that the haze optical thickness steeply increases toward higher latitudes. (C) 2002 Elsevier Science (USA). C1 Free Univ Amsterdam, Dept Phys & Astron, NL-1081 HV Amsterdam, Netherlands. Free Univ Amsterdam, Dept Phys & Astron, NL-1081 HV Amsterdam, Netherlands. Royal Netherlands Meteorol Inst, NL-3730 AE De Bilt, Netherlands. Univ Amsterdam, Astron Inst Anton Pannekoek, Amsterdam, Netherlands. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Braak, CJ (reprint author), Free Univ Amsterdam, Dept Phys & Astron, De Boelelaan 1081, NL-1081 HV Amsterdam, Netherlands. NR 52 TC 13 Z9 14 U1 0 U2 2 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD JUN PY 2002 VL 157 IS 2 BP 401 EP 418 DI 10.1006/icar.2002.6846 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 568NK UT WOS:000176548300009 ER PT J AU Carlson, RW Anderson, MS Johnson, RE Schulman, MB Yavrouian, AH AF Carlson, RW Anderson, MS Johnson, RE Schulman, MB Yavrouian, AH TI Sulfuric acid production on Europa: The Radiolysis of sulfur in water ice SO ICARUS LA English DT Article DE Europa; radiation chemistry; surfaces-satellite, magnetospheres ID HYDROGEN-PEROXIDE; EVOLUTION; SURFACE; TEMPERATURES; IRRADIATION; BOMBARDMENT; OXIDATION; MIXTURES; SPECTRUM; GANYMEDE AB Europa's surface is chemically altered by radiolysis from energetic charged particle bombardment. It has been suggested that hydrated sulfuric acid (H2SO4 . nH(2)O) is a major surface species and is part of a radiolytic sulfur cycle, where a dynamic equilibrium exists between continuous production and destruction of sulfur polymers S-x, sulfur dioxide SO2, hydrogen sulfide H2S, and H2SO4 . nH(2)O. We measured the rate of sulfate anion production for cyclo-octal sulfur grains in frozen water at temperatures, energies, and dose rates appropriate for Europa using energetic electrons. The measured rate is G(Mixture) (SO42-) = f(Sulfur) (r(0)/r)beta G(1) molecules (100 eV)(-1), where f(Sulfur) is the sulfur weight fraction, r is the grain radius, r(0) = 50 mum, beta approximate to 1.9, and G(1) = 0.4 +/- 0.1. Equilibrium column densities N are derived for Europa's surface and follow the ordering N(H2SO4) much greater than N(S) > N(SO2) > N(H2S). The lifetime of a sulfur atom on Europa's surface for radiolysis to H2SO4 is tau(-S) = 120(r/r(0))(beta) years. Rapid radiolytic processing hides the identity of the original source of the sulfurous material, but Iogenic plasma ion implantation and an acidic or salty ocean are candidate sources. Sulfate salts, if present, would be decomposed in <3800 years and be rapidly assimilated into the sulfur cycle. (C) 2002 Elsevier Science (USA). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Virginia, Charlottesville, VA 22903 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Carlson, RW (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 49 TC 74 Z9 74 U1 0 U2 16 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD JUN PY 2002 VL 157 IS 2 BP 456 EP 463 DI 10.1006/icar.2002.6858 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 568NK UT WOS:000176548300013 ER PT J AU Bakes, ELO McKay, CP Bauschlicher, CW AF Bakes, ELO McKay, CP Bauschlicher, CW TI Photoelectric charging of submicron aerosols and macromolecules in the Titan haze SO ICARUS LA English DT Article DE Titan; stratospheric chemistry; aromatics; aerosol charging ID POLYCYCLIC AROMATIC-HYDROCARBONS; PHOTODISSOCIATION REGIONS; INFRARED-EMISSION; PHYSICAL MODEL; ATMOSPHERE; PHOTOCHEMISTRY; CHEMISTRY; GROWTH; CLOUDS AB We quantify the charge states of submicrometer aerosols and aromatic macromolecules in Titan's organic haze. The aerosol charge is balanced between the recombination of positive ions with the aerosol plus the ejection of electrons from the aerosol via the UV-driven photoelectric effect and the recombination of electrons with the aerosol. During the day, the dominant charge state for submicrometer aerosols is positive. Macromolecules composed of fewer than 32 carbon atoms with low electron affinities (<1.0 eV) are neutral, while the rest are mainly, neutral and negatively charged with a small fraction (similar to10%) becoming positively charged at higher (greater than or equal to300 km) altitudes. At night, Titan's aerosol population becomes uniformly neutral and negatively charged. The time taken for a nighttime aerosol to change from being negatively charged to its most probable daytime positive charge is on the order of a few seconds for the largest submicrometer aerosols, while macromolecules tend to persist in an anionic charge state for one to several Earth days. Charging strongly influences aerosol agglomeration via Coulomb attraction and may account for the seasonal variations in the albedo of the Titan haze at midrange (similar to200-250 km) altitudes. Enhanced agglomeration may also efficiently produce a source of condensation nuclei for the daily rainout of methane. In addition, the difference in aerosol charge between Titan's day and night (or summer and winter) phases will produce dramatically different chemistries which must be accounted for in future photochemical models. Finally, if there are PAH-like macromolecules in the Titan haze, Cassini Huygens should be able to observe these charge differences, with neutral macromolecules emitting strongly at 3.3 and 11.2 mum, cationic macromolecules emitting between 6.2 and 8.6 mum, and anionic macromolecules emitting in both infrared spectral regions. (C) 2002 Elsevier Science (USA). C1 NASA, Ames Res Ctr, SETI Inst, Moffett Field, CA 94035 USA. NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. NASA, Ames Res Ctr, Space Technol Div, Moffett Field, CA 94035 USA. RP Bakes, ELO (reprint author), NASA, Ames Res Ctr, SETI Inst, Mail Stop 245-3, Moffett Field, CA 94035 USA. NR 38 TC 26 Z9 26 U1 0 U2 6 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD JUN PY 2002 VL 157 IS 2 BP 464 EP 475 DI 10.1006/icar.2002.6843 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 568NK UT WOS:000176548300014 ER PT J AU Wilson, JK Mendillo, M Baumgardner, J Schneider, NM Trauger, JT Flynn, B AF Wilson, JK Mendillo, M Baumgardner, J Schneider, NM Trauger, JT Flynn, B TI The dual sources of Io's sodium clouds SO ICARUS LA English DT Article DE Io; atmospheric dynamics; satellite atmospheres; magnetospheres ID RADIO OCCULTATION MEASUREMENTS; GROUND-BASED OBSERVATIONS; PLASMA TORUS; JOVIAN MAGNETOSPHERE; ATMOSPHERIC ESCAPE; CYCLOTRON WAVES; JUPITER; NEBULA; IONOSPHERE; ENCOUNTER AB Io's sodium clouds result mostly from a combination of two atmospheric escape processes at Io. Neutralization of Na+ and/or NaX- pickup ions produces the "stream" and the "jet" and results in a rectangular-shaped sodium nebula around Jupiter. Atmospheric sputtering of Na by, plasma torus ions produces the "banana cloud" near Io and a diamond-shaped sodium nebula. Charge exchange of thermal Na+ with Na in Io's atmosphere does not appear to be a major atmospheric ejection process. The total ejection rate of sodium from In varied from 3 x 10(26) to 25 x 10(26) atoms/s over seven years of observations. Our results provide further evidence that Io's atmospheric escape is driven from collisionally thick regions of the atmosphere rather than from the exosphere. (C) 2002 Elsevier Science (USA). C1 Boston Univ, Ctr Space Phys, Boston, MA 02215 USA. Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80309 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. RP Wilson, JK (reprint author), Boston Univ, Ctr Space Phys, 725 Commonwealth Ave, Boston, MA 02215 USA. RI Mendillo, Michael /H-4397-2014 NR 56 TC 23 Z9 23 U1 0 U2 0 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD JUN PY 2002 VL 157 IS 2 BP 476 EP 489 DI 10.1006/icar.2002.6821 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 568NK UT WOS:000176548300015 ER PT J AU Gamba, P Houshmand, B AF Gamba, P Houshmand, B TI Comparison of C- and X-band InSAR data for 3D characterization of an urban area SO IEEE AEROSPACE AND ELECTRONIC SYSTEMS MAGAZINE LA English DT Article AB In this paper we offer an overview of a number of algorithms suitable for 3D characterization of an urban environment from interferometric SAR data. By means of these algorithms we compare fine resolution C- and X-band SAR measurements over the same area to understand what useful information can be derived from these measurements. In addition we examine the similarities and differences of these data sets that are acquired with different frequency bands, bandwidths, and radar look direction. These data sets are recorded over Los Angeles, California, by the C-band NASA/JPL AIRSAR system, and by X-band Intermap Star-3i system. We analyze the original range measurements as reconstructed after the phase unwrapping procedure, the bald earth topography that we were able to retrieve, and the 3D shapes of some of the buildings in the UCLA area. Our results show that both data sets provide useful information of urban 3D characteristics. The better ground resolution of the X-band system results in better building shape extraction. Lower resolution of the C-band data, surprisingly, was not a limiting factor for extraction of large building structures. We demonstrate that it is possible to extract the terrain elevation model (bald earth topography), and the heights of large building structures by means of our algorithms. C1 Univ Pavia, Dipartimento Elettron, I-27100 Pavia, Italy. Jet Prop Lab, Pasadena, CA USA. RP Gamba, P (reprint author), Univ Pavia, Dipartimento Elettron, Via Ferrata 1, I-27100 Pavia, Italy. RI Gamba, Paolo/G-1959-2010 OI Gamba, Paolo/0000-0002-9576-6337 NR 10 TC 4 Z9 4 U1 0 U2 2 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 JUN PY 2002 VL 17 IS 6 BP 9 EP 15 DI 10.1109/MAES.2002.1010115 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA 563EL UT WOS:000176242800004 ER PT J AU Yang, RQ Bradshaw, JL Bruno, JD Pham, JT Wortman, DE AF Yang, RQ Bradshaw, JL Bruno, JD Pham, JT Wortman, DE TI Mid-infrared type-II interband cascade lasers SO IEEE JOURNAL OF QUANTUM ELECTRONICS LA English DT Article DE diode lasers; mid-infrared; quantum-well lasers; semiconductor superlattices ID CONTINUOUS-WAVE OPERATION; LIGHT-EMITTING-DIODES; QUANTUM-WELL LASERS; THEORETICAL PERFORMANCE; POWER EFFICIENCY; HEAT-SINKING; W-LASER; HETEROSTRUCTURES; PROGRESS AB Interband cascade (IC) lasers that utilize optical transitions between the conduction and valence bands in a staircase of Sb-based type-II quantum wells (QWs) represent a new class of mid-IR diode lasers. By combining the advantages of quantum cascade lasers and type-II QW interband lasers, type-IIIC lasers show promise of operating in continuous-wave (CW) mode up to room temperature with high output powers. Significant advances toward Such high performance have been reported in terms of record-high differential external quantum efficiency (DEQE > 600%), peak output power (similar to6 W/facet at 80 K), CW power conversion efficiency (>16% at 80 K), and room-temperature operation under pulsed conditions. Here, we will review the progress made in the past few years and discuss the issues encountered during the development. Also, the current status of type-IIIC lasers and the remaining challenges will be discussed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Maxion Technol Inc, Hyattsville, MD 20782 USA. RP Yang, RQ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Bradshaw, John/E-8330-2011 NR 51 TC 54 Z9 55 U1 1 U2 6 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9197 J9 IEEE J QUANTUM ELECT JI IEEE J. Quantum Electron. PD JUN PY 2002 VL 38 IS 6 BP 559 EP 568 AR PII S0018-9197(02)05017-0 DI 10.1109/JQE.2002.1005406 PG 10 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 557VU UT WOS:000175929900005 ER PT J AU Elci, H Longman, RW Phan, MQ Juang, JN Ugoletti, R AF Elci, H Longman, RW Phan, MQ Juang, JN Ugoletti, R TI Simple learning control made practical by zero-phase filtering: Applications to robotics SO IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS I-REGULAR PAPERS LA English DT Article DE 2-D systems; iterative learning control; precision motion control; robotics; zero-phase filtering ID REPETITIVE CONTROL; DYNAMIC CONTROL; IMPLEMENTATION; MANIPULATORS; STABILIZATION AB Iterative learning control (ILC) applies to control systems that perform the same finite-time tracking command repeatedly. It iteratively adjusts the command from one repetition to the next in order to reduce the tracking error. This creates a two-dimensional (2-D) system, with time step and repetition number as independent variables. The simplest form of ILC uses only one gain times one error in the previous repetition, and can be shown to converge to the zero-tracking error independent of the system dynamics. Hence, it appears very effective from a mathematical perspective. However, in practice, there are unacceptable learning transients. A zero-phase low-pass filter is introduced here to eliminate the bad transients. The main purpose of this paper is to supply a journal presentation of experiments on a commercial robot that demonstrate the effectiveness of this approach, improving the tracking accuracy of the robot performing a high speed maneuver by a factor of 100 in six repetitions. Experiments using a two-gain ILC reaches this error level in only three iterations. It is suggested that these two simple ILC laws are the equivalent for learning control, of proportional and PD control in classical control system design. Thus, what was an impractical approach, becomes practical, easy to apply, and effective. C1 Columbia Univ, Dept Mech Engn, New York, NY 10027 USA. Dartmouth Coll, Hanover, NH 03755 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Lockheed Engn & Sci Co, Hampton, VA 23681 USA. EM Haluk_Elci@monitor.com; RWL4@columbia.edu; Minh.Q.Phan@dartmouth.edu; j.juang@larc.nasa.gov NR 47 TC 92 Z9 93 U1 0 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 1549-8328 EI 1558-0806 J9 IEEE T CIRCUITS-I JI IEEE Trans. Circuits Syst. I-Regul. Pap. PD JUN PY 2002 VL 49 IS 6 BP 753 EP 767 AR PII S1057-7122(02)05602-7 DI 10.1109/TCSI.2002.1010031 PG 15 WC Engineering, Electrical & Electronic SC Engineering GA 563KW UT WOS:000176255700006 ER PT J AU Keihm, SJ Bar-Sever, Y Liljegren, JC AF Keihm, SJ Bar-Sever, Y Liljegren, JC TI WVR-GPS comparison measurements and calibration of the 20-32 GHz tropospheric water vapor absorption model SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE global positioning satellite (GPS); opacity; path delay; vapor absorption model; water vapor radiometer ID MILLIMETER-WAVE-PROPAGATION; MICROWAVE RADIOMETERS; DOPPLER TRACKING; PATH DELAY; SPACECRAFT AB Collocated measurements of opacity (from water vapor radiometer brightness temperatures) and wet path delay (from ground-based tracking of global positioning satellites) are used to constrain the model of atmospheric water vapor absorption in the 20-32 GHz band. A differential approach is presented in which the slope of opacity-versus-wet delay data is used as the absorption model constraint. This technique minimizes the effects of radiometric calibration errors and oxygen model uncertainties in the derivation of a best-fit vapor absorption model. A total of approximately five months of data was obtained from two experiment sites. At the Cloud and Radiation Testbed (CART) site near Lamont, OK, three independent water vapor radiometers (WVRs) provided near-continuous opacity measurements over the interval July-September 1998. At the NASA/Goldstone tracking station in the California desert two WVRs obtained opacity data over the September-October 1997 interval. At both sites a global positioning satellite (GPS) receiver and surface barometer obtained the data required for deriving the zenith wet delays over the same time frames. Measured values of the opacity-versus-wet delay slope parameter were obtained at four WVR frequencies (20.7, 22.2, 23.8, and 31.4 GHz) and compared with predictions of four candidate absorption models referenced in the recent literature. With one exception, all three models provide agreement within 5% of the opacity-versus-wet delay slope measurements at all WVR frequencies at both sites. One model provides agreement for all channels at both sites to the 2-3% level. This absorption model accuracy level represents a significant improvement over that attainable using radiosondes. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Argonne Natl Lab, Div Environm Res, Argonne, IL USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 36 TC 9 Z9 9 U1 0 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0196-2892 EI 1558-0644 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD JUN PY 2002 VL 40 IS 6 BP 1199 EP 1210 DI 10.1109/TGRS.2002.800274 PG 12 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 578JR UT WOS:000177114500001 ER PT J AU Wang, JR Racette, P Triesky, ME Browell, EV Ismail, S Chang, LA AF Wang, JR Racette, P Triesky, ME Browell, EV Ismail, S Chang, LA TI Profiling of atmospheric water vapor with MIR and LASE SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE millimeter-wave radiometry; remote sensing; water vapor ID WAVE RADIOMETRIC MEASUREMENTS; MICROWAVE RADIOMETRY; DIFFERENTIAL ABSORPTION; BRIGHTNESS TEMPERATURES; MOISTURE PROFILES; CIRRUS CLOUDS; AIRBORNE; LIDAR; RETRIEVAL; CLEAR AB Concurrent measurements of atmospheric water vapor profiles were conducted over the Atlantic Ocean. on September 25, 1995 with both the millimeter-wave imaging radiometer (MIR) and lidar atmospheric sounding experiment (LASE) on board, the NASA ER-2 aircraft. LASE provides high precision measurements of both aerosol backscatter And water vapor. profiles; aerosol backscatter has a vertical resolution of 60 m while the water vapor profiles have a resolution of 330 m in the low-to-mid. troposphere and 550 m in the upper troposphere. Therefore, LASE measurements provide an excellent resource for. assessing the capabilities and limitations of MIR as a water vapor profiler. Previously, the Water vapor profiles retrieved from the MIR measurements have been compared with those of rawinsonde and Raman lidar observations at point locations. The frequency and extent of the comparisons made in that fashion were largely constrained by he,:requirement of near coincidence in time and space. The data acquired concurrently by MIR and LASE from this ER-2 aircraft flight enable the comparison of MIR-retrieved and LASE-measured moisture profiles over a long stretch of time and space. In addition, the LASE-measured profiles of aerosol backscatter provide a resource to assess the impact of clouds on the retrieval of water vapor profiles from the MIR measurements. It, is shown that profiles of Water vapor mixing ratio retrieved from the MIR data generally conform to those measured by the LASE; however, differences. in the values of mixing ratio at individual, altitude levels are quite often not. small. The standard deviations of these differences are found to be about +/-0.98, +/-0.84, +/-0.95, +/-0.42, and +/-0.06 g/kg at altitudes of 1.25, 2.75, 4.75, 7.25, and 10.25 km. It is demonstrated that a substantial portion of these differences are due to the poor vertical resolution inherent in the profile retrieval using the MIR radiometric measurements. Additionally, MIR water vapor profiling under cloudy conditions is demonstrated, and it is shown that location and height of the low-altitude clouds estimated from the retrieval process were generally consistent with those observed by, the LASE. For study cases Where cirrus clouds are present, retrievals from, the MIR data over-estimate the mixing ratio; this over-estimate is provoked by brightness temperature decreases that occur at 183-220 GHz within these regions. Undoubtedly, the retrieval method needs an additional procedure to account for the millimeter-wave scattering by cloud ice particles so that water vapor profiling can be improved within regions where cirrus clouds are present. C1 NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Futuretech Corp, Gaithersburg, MD 20878 USA. RP Wang, JR (reprint author), NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. NR 25 TC 4 Z9 4 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 JUN PY 2002 VL 40 IS 6 BP 1211 EP 1219 DI 10.1109/TGRS.2002.800227 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 578JR UT WOS:000177114500002 ER PT J AU Wang, JR Racette, P Triesky, ME Manning, W AF Wang, JR Racette, P Triesky, ME Manning, W TI Retrievals of column water vapor using millimeter-wave radiometric measurements SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE millimeter-wave radiometry; remote sensing; water vapor ID TOTAL PRECIPITABLE WATER; 183 GHZ; MICROWAVE RADIOMETRY; IMAGING RADIOMETER; PROFILES AB The airborne millimeter-wave imaging radiometer (MIR) measurements conducted over the midwest region of the continental United States during January/February 1997 and over the Alaska-Arctic region during May 1998 are used to estimate column water vapor W < 0.8 g/cm(2) under a clear sky. On board the same aircraft are two other instruments, the cloud lidar system (CLS) and MODerate-resolution imaging spectrometer (MODIS) airborne simulator (MAS), which provide cloud cover information and independent measurements of W, respectively. The MIR-estimated W values are compared and found to be in very good agreement with those measured by rawinsondes at near concurrence. A close correlation is found between the MIR-estimated W and that estimated from the MAS near-IR reflectance ratios. Water surface emissivities at several MIR frequencies are obtained in the process of the W retrieval from several flights over the mid-west lakes. These estimated emissivities compared favorably with values calculated for a calm water surface, which are based on a recent dielectric permittivity model and MAS-measured surface temperatures. The results from all comparisons strongly demonstrate the soundness of the technique for estimating W. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland, Joint Ctr Earth Syst Technol, Baltimore, MD 21250 USA. RP Wang, JR (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 17 TC 13 Z9 13 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 JUN PY 2002 VL 40 IS 6 BP 1220 EP 1229 DI 10.1109/TGRS.2002.800433 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 578JR UT WOS:000177114500003 ER PT J AU Zhao, YH Liu, AK Long, DG AF Zhao, YH Liu, AK Long, DG TI Validation of sea ice motion from QuikSCAT with those from SSM/I and buoy SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE QuikSCAT; sea ice motion; special sensor nucrowave/imager (SSM/I); wavelet transform ID WAVELET ANALYSIS; DRIFT AB Arctic sea ice motion for the period from October 1999 to March 2000 derived from QuikSCAT and special sensor microwave/imager (SSM/I) data using the wavelet analysis method agrees well with ocean buoy observations. Results from QuikSCAT and SSM/I are compatible when compared with buoy observations and complement each other. Sea ice drift merged from daily results from QuikSCAT, SSM/I, and buoy data gives more complete coverage of sea ice motion. Based on observations of six months of sea ice motion maps, the sea ice motion maps in the Arctic derived from QuikSCAT data appear to have smoother (less noisy) patterns than those from NSCAT, especially in boundary areas, possibly due to constant radar scanning incidence angle. For late summer, QuikSCAT data can provide good sea ice motion information in the Arctic as early as the beginning of September. For early summer, QuikSCAT can provide at least partial sea ice motion information until mid-June. In the Antarctic, a case study shows that sea ice motion derived from QuikSCAT data is consistent with pressure field contours. C1 NASA, Goddard Space Flight Ctr, Oceans & Ice Branch, Greenbelt, MD 20771 USA. Brigham Young Univ, Dept Elect & Comp Engn, Provo, UT 84602 USA. RP Zhao, YH (reprint author), NASA, Goddard Space Flight Ctr, Oceans & Ice Branch, Greenbelt, MD 20771 USA. RI Long, David/K-4908-2015 OI Long, David/0000-0002-1852-3972 NR 10 TC 30 Z9 31 U1 1 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 JUN PY 2002 VL 40 IS 6 BP 1241 EP 1246 DI 10.1109/TGRS.2002.800442 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 578JR UT WOS:000177114500005 ER PT J AU Zhou, GQ Jezek, K Wright, W Rand, J Granger, J AF Zhou, GQ Jezek, K Wright, W Rand, J Granger, J TI Orthorectification of 1960s satellite photographs covering Greenland SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE declassified intelligence satellite photography; (DISP) imagery; Greenland ice sheet; image processing; mosaic; orthorectification; photogrammetry ID AIRBORNE SCANNER IMAGERY; GEOMETRIC CORRECTION; HIGH-RESOLUTION; FILTERS; NOISE AB This article presents a rigorous, high-precision model for geometric orthorectification of declassified intelligence satellite photography (DISP) imagery for the generation of a seamless, full-coverage mosaic of the Greenland ice sheet. This model integrates the bundle adjustment method and satellite orbital parameters, solving for interior orientation (including lens distortion) and exterior orientation parameters simultaneously. In addition, the techniques of adaptive filtering, bright-strip removal, radiometric balancing, and mosaic postprocessing are discussed. Two full-coverage mosaics of Greenland using 24 DISP images from eight orbits of the ARGON 9034A Mission of May 1962 and 36 images from 14 orbits of the 9058A/59A mission of October 1963 were created. The average planimetric accuracy (relative to the synthetic aperture radar (SAR) mosaic) is about 168 m from statistical measurements of 182 points in topographically flat areas and 186 m from statistical measurements of 201 points in mountainous areas. The two mosaic products have been delivered to the U.S. National Snow and Ice Data Center (NSIDC) for use by the research community. C1 Old Dominion Univ, Dept Civil Engn & Technol, Norfolk, VA 23529 USA. Ohio State Univ, Dept Geol Sci, Byrd Polar Res Ctr, Columbus, OH 43210 USA. NASA, GSF, Wallops Flight Facil, Lab Hydrospher Facil, Wallops Isl, VA 23337 USA. RP Zhou, GQ (reprint author), Old Dominion Univ, Dept Civil Engn & Technol, Norfolk, VA 23529 USA. NR 29 TC 23 Z9 23 U1 0 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 JUN PY 2002 VL 40 IS 6 BP 1247 EP 1259 DI 10.1109/TGRS.2002.800240 PG 13 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 578JR UT WOS:000177114500006 ER PT J AU Vanderbilt, VC Perry, GL Livingston, GP Ustin, SL Barrios, MCD Beron, FM Leroy, MM Balois, JY Morrissey, LA Shewchuk, SR Stearn, JA Zedler, SE Syder, JL Bouffies-Cloche, S Herman, M AF Vanderbilt, VC Perry, GL Livingston, GP Ustin, SL Barrios, MCD Beron, FM Leroy, MM Balois, JY Morrissey, LA Shewchuk, SR Stearn, JA Zedler, SE Syder, JL Bouffies-Cloche, S Herman, M TI Inundation discriminated using sun glint SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE bidirectional reflectance; bidirectional reflectance distribution function (BRDF); inundation; methane; specular reflection of sunlight; wetlands ID LAND-COVER DATA; METHANE EMISSIONS; WETLAND TUNDRA; WATER-BALANCE; ARCTIC TUNDRA; ATMOSPHERE; BOREAS; DISCOVER; CLIMATE; ENERGY AB Inundation is linked to water, carbon, and energy budgets at landscape to global scales. We describe a new remote-sensing technique for identifying inundated areas based on the properties of the glitter-the strong, angular signature reflection that is characteristic of surface water and uncharacteristic of other cover types. We discriminated three cover types-vegetation emergent above inundated soils, open water, and noninundated cover types-from analysis of directional data collected in the red spectral band by the airborne POLDER (polarization and directionality of earth's reflectance) sensor. We found that values of the normalized difference vegetation index (NDVI) decreased dramatically in the glitter direction, providing an indication of surface water. Application of our new technique holds promise for mapping the seasonal and interannual extent of inundation, a key descriptor of wetlands hydrology. C1 NASA, Ames Res Ctr, Natl Res Council, Moffett Field, CA 94035 USA. Univ Vermont, Burlington, VT 05405 USA. Univ Calif Davis, Davis, CA 95616 USA. Hidrogeocol Ltda, Bogota, Colombia. CEA, DSM, LMCE, F-91191 Gif Sur Yvette, France. MEDIAS France, F-31055 Toulouse, France. UST Lille, Opt Atmospher Lab, F-59655 Villeneuve Dascq, France. Saskatchewan Res Council, Saskatoon, SK S7N 2X8, Canada. NASA, Ames Res Ctr, Johnson Control Corp, Moffett Field, CA 94035 USA. RP Vanderbilt, VC (reprint author), NASA, Ames Res Ctr, Natl Res Council, Moffett Field, CA 94035 USA. RI Breon, Francois-Marie/M-4639-2016 OI Breon, Francois-Marie/0000-0003-2128-739X NR 32 TC 9 Z9 9 U1 1 U2 5 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 JUN PY 2002 VL 40 IS 6 BP 1279 EP 1287 DI 10.1109/TGRS.2002.800233 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 578JR UT WOS:000177114500009 ER PT J AU Wang, JR AF Wang, JR TI A comparison of the MIR-estimated and model-calculated fresh water surface emissivities at 89, 150, and 220 GHz SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE millimeter-wave radiometry; remote sensing; surface emissivity ID WAVE IMAGING RADIOMETER; MICROWAVE RADIOMETERS; VAPOR; PERMITTIVITY; FREQUENCIES; SATELLITE; CLOUD; ICE; PRECIPITATION; SPECTROMETER AB The airborne millimeter-wave imaging radiometer (MIR) measurements over three lakes (surface temperature similar to273 K) in the Midwest region of the USA during February 1997 were used to estimate surface emissivities at 89, 150, and 220 GHz and the results were compared with those calculated from three different dielectric permittivity models for fresh water. The measurements were during clear and dry atmospheric conditions so that the column water vapor could be accurately retrieved and its effect on the MIR measurements predicted. The standard deviations of the estimated emissivities were found to be about 0.003, 0.004, and 0.008 for 89, 150, and 220 GHz, respectively. The errors of the estimation were calculated to be +/-0.005, +/-0.006, and +/-0.011 in the same order of frequency, respectively, based on the MIR measurement accuracy of +/-1 K in the brightness temperature range of 190-290 K. The estimated emissivities at normal incidence, under the assumption of a calm water surface, compare quite well with values generated by the model of Stogryn et al. [1]. These estimated values are slightly lower than those calculated from the model of Liebe et al. [2] at both 89 and 150 GHz. The estimated 89 GHz emissivity is higher than that calculated from the model of Ellison et al. [3]. Additionally, the retrievals using different models of atmospheric absorption as well as off-nadir measurements of the MIR are explored. The impact of these retrievals on the comparison of estimated and calculated emissivities is discussed. C1 NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. RP Wang, JR (reprint author), NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. NR 28 TC 12 Z9 12 U1 1 U2 6 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 JUN PY 2002 VL 40 IS 6 BP 1356 EP 1365 DI 10.1109/TGRS.2002.800230 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 578JR UT WOS:000177114500016 ER PT J AU Johnston, AH Miyahira, TF AF Johnston, AH Miyahira, TF TI Energy dependence of proton damage in optical emitters SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 6th European Conference on Radiation and its Effects on Components and Systems CY SEP 10-14, 2001 CL GRENOBLE, FRANCE SP Techn Informat & Microelectr Comp Architecture Lab DE laser diodes; light-emitting diodes (LEDs); optoelectronic devices; radiation effect ID LIGHT-EMITTING-DIODES AB The energys dependence of proton displacement damage effects is investigated for light-emitting diodes (LEDs) and laser diodes. Injection-enhanced annealing occurs more rapidly when devices are irradiated with protons below 50 MeV compared with annealing from 200-MeV protons. A different interpretation of damage in amphoterically doped LEDs is used to show that the dependence of damage on energy is relatively flat for energies above 50 MeV, in contrast to older results in the literature that show a continued decrease in damage at higher energies. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Johnston, AH (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 17 TC 10 Z9 11 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 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 2002 VL 49 IS 3 BP 1426 EP 1431 AR PII S0018-9499(02)05805-7 DI 10.1109/TNS.2002.1039678 PN 3 PG 6 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 605HE UT WOS:000178671300020 ER PT J AU Sternberg, AL Massengill, LW Schrimpf, RD Boulghassoul, Y Barnaby, HJ Buchner, S Pease, RL Howard, JW AF Sternberg, AL Massengill, LW Schrimpf, RD Boulghassoul, Y Barnaby, HJ Buchner, S Pease, RL Howard, JW TI Effect of amplifier parameters on single-event transients in an inverting operational amplifier SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 6th European Conference on Radiation and its Effects on Components and Systems CY SEP 10-14, 2001 CL GRENOBLE, FRANCE SP Techn Informat & Microelectr Comp Architecture Lab DE linear circuits; operational amplifier; single event transient ID INTEGRATED-CIRCUITS; COMPARATORS; ANALOG AB Laser data and simulation tools are combined to investigate the single-event transient response of the LM124 operational amplifier. The effect of the bandwidth and gain on transients originating in different stages in the operational amplifier is studied. We found that the single-event transient response of the LM124 operational amplifier in an inverting configuration was dependent on the bandwidth of the amplifier, the gain, and on the values of the resistors used to program the gain of the amplifier. We show the results of simulations which illustrate how these changes impact the single-event transient response of the amplifier. An analysis of the results suggests which properties of an operational amplifier will provide a better single-event transient response. C1 Vanderbilt Univ, Dept Elect Engn & Comp Sci, Nashville, TN 37235 USA. USN, Res Lab, Washington, DC 20375 USA. RLP Res, Albuquerque, NM 87122 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Sternberg, AL (reprint author), Vanderbilt Univ, Dept Elect Engn & Comp Sci, 221 Kirkland Hall, Nashville, TN 37235 USA. RI Schrimpf, Ronald/L-5549-2013 OI Schrimpf, Ronald/0000-0001-7419-2701 NR 12 TC 29 Z9 31 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 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 2002 VL 49 IS 3 BP 1496 EP 1501 AR PII S0018-9499(02)05811-2 DI 10.1109/TNS.2002.1039690 PN 3 PG 6 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 605HE UT WOS:000178671300032 ER PT J AU Edmonds, LD AF Edmonds, LD TI A method for correcting cosine-law errors in SEU test data SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article DE alpha law; cosine law; single-event upset (SEU); SEU cross section ID CROSS-SECTION; ION TRACKS; INTEGRATED-CIRCUITS; CHARGE-COLLECTION; RATE PREDICTION; UPSET AB Single-event upset tests often change the angle of the ion beam relative to the device to mimic a change in ion linear energy transfer, and the data are then converted via an assumed cosine law. The converted data are intended to represent device susceptibility at normal incidence, but the cosine law sometimes contains. considerable error. The standard method for correcting this error is based on the rectangular parallelepiped (RPP) model. However, exact analytical expressions derived from this model are not particularly simple, so specialized computer codes are needed unless approximations are used. This paper starts with an alternate physical model, utilizing a charge-collection efficiency function, and derives an exact analytical result (called the alpha law here) that replaces the cosine law but is almost as simple as the cosine law, even when device susceptibility has a strong azimuthal dependence. The same model can be used to calculate (via numerical integrations) rates in a known heavy-ion environment. An alternative is to use model parameters to construct the parameters for an integrated RPP calculation of rates. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Edmonds, LD (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 16 TC 8 Z9 8 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 2002 VL 49 IS 3 BP 1522 EP 1538 AR PII S0018-9499(02)05807-0 DI 10.1109/TNS.2002.1039696 PN 4 PG 17 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 605HG UT WOS:000178671600002 ER PT J AU Seraji, H Howard, A AF Seraji, H Howard, A TI Behavior-based robot navigation on challenging terrain: A fuzzy logic approach SO IEEE TRANSACTIONS ON ROBOTICS AND AUTOMATION LA English DT Article DE behavior-based navigation; fuzzy logic; mobile robots; robot navigation; rough terrain; sensor-based navigation; traversability ID MOBILE ROBOT; SYSTEM AB This paper presents a new strategy for behavior-based navigation of field mobile robots on challenging terrain, using a fuzzy logic approach and a novel measure of terrain traversability. A key feature of the proposed approach is real-time assessment of terrain characteristics and incorporation of this information in the robot navigation strategy. Three terrain characteristics that strongly affect its traversability, namely, roughness, slope, and discontinuity, are extracted from video images obtained by on-board cameras. This traversability data is used to infer, in real time, the terrain Fuzzy Rule-Based Traversability Index, which succinctly quantifies the ease of traversal of the regional terrain by the mobile robot. A new traverse-terrain behavior is introduced that uses the regional traversability index to guide the robot to the safest and the most traversable terrain region. The regional traverse-terrain behavior is complemented by two other behaviors, local avoid-obstacle and global seek-goal. The recommendations of these three behaviors are integrated through adjustable weighting factors to generate the final motion command for the robot. The weighting factors are adjusted automatically, based on the situational context of the robot. The terrain assessment and robot navigation algorithms are implemented on a Pioneer commercial robot and field-test studies are conducted. These studies demonstrate that the robot possesses intelligent decision-making capabilities that are brought to bear in negotiating hazardous terrain conditions during the robot motion. C1 CALTECH, Jet Prop Lab, NASA, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, NASA, Pasadena, CA 91109 USA. NR 30 TC 127 Z9 134 U1 1 U2 16 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 1042-296X J9 IEEE T ROBOTIC AUTOM JI IEEE Trans. Robot. Autom. PD JUN PY 2002 VL 18 IS 3 BP 308 EP 321 AR PII S1042-296X(02)06337-1 DI 10.1109/TRA.2002.1019461 PG 14 WC Automation & Control Systems; Engineering, Electrical & Electronic; Robotics SC Automation & Control Systems; Engineering; Robotics GA 575AN UT WOS:000176923500005 ER PT J AU Gramopadhye, AK Melloy, BJ Nair, SN Vora, J Orhan, C Duchowski, AT Shivashankaraiah, V Rawls, T Kanki, B AF Gramopadhye, AK Melloy, BJ Nair, SN Vora, J Orhan, C Duchowski, AT Shivashankaraiah, V Rawls, T Kanki, B TI The use of binocular eye tracking in virtual reality for aircraft inspection training SO INTERNATIONAL JOURNAL OF INDUSTRIAL ENGINEERING-THEORY APPLICATIONS AND PRACTICE LA English DT Article DE visual inspection; training; virtual reality; eye tracking AB The aircraft maintenance industry is a complex system consisting of several interrelated human and machine components. The linchpin of this system, however, is the human. Recognizing this, the Federal Aviation Administration (FAA) has pursued human factors related research. In the maintenance arena the research has focused on the aircraft inspection process and the aircraft inspector. Training has been identified as the primary intervention strategy to improve the quality and reliability of aircraft inspection. In response to this need, the paper outlines the development of a binocular eye tracking Virtual Reality system for aircraft inspection training focused on improving aircraft inspection performance and ultimately aviation safety. The aesthetic appearance of the environment is driven by standard graphical techniques augmented by realistic texture maps of the physical environment. A "virtual flashlight" is provided to simulate a tool used by inspectors. The user's gaze direction, as well as head position and orientation are tracked to allow recording of the user's gaze locations within the environment. These gaze locations, or scanpaths, are calculated as gaze/polygon intersections, enabling comparison of fixated points with stored locations of artificially generated defects located in the environment interior. Recorded scanpaths provide a means of comparison of the performance of experts to novices, thereby gauging the effects of training. C1 Clemson Univ, Dept Ind Engn, Clemson, SC 29631 USA. Clemson Univ, Dept Comp Sci, Clemson, SC 29631 USA. NASA, Ames Res Ctr, Human Factors Res & Technol Div, Moffett Field, CA 94035 USA. RP Gramopadhye, AK (reprint author), Clemson Univ, Dept Ind Engn, Clemson, SC 29631 USA. NR 23 TC 0 Z9 1 U1 1 U2 4 PU UNIV CINCINNATI INDUSTRIAL ENGINEERING PI CINCINNATI PA UNIV CINCINNATI, CINCINNATI, OH 45221-0116 USA SN 1072-4761 J9 INT J IND ENG-THEORY JI Int. J. Ind. Eng.-Theory Appl. Pract. PD JUN PY 2002 VL 9 IS 2 BP 123 EP 132 PG 10 WC Engineering, Industrial; Engineering, Manufacturing SC Engineering GA 568GB UT WOS:000176533100002 ER PT J AU Hilburger, MW Starnes, JH AF Hilburger, MW Starnes, JH TI Effects of imperfections on the buckling response of compression-loaded composite shells SO INTERNATIONAL JOURNAL OF NON-LINEAR MECHANICS LA English DT Article AB The results of an experimental and analytical study of the effects of initial imperfections on the buckling and postbuckling response of three unstiffened thin-walled compression-loaded graphite-epoxy cylindrical shells with different orthotropic and quasi-isotropic shell-wall laminates are presented. The results identify the effects of traditional and non-traditional initial imperfections on the non-linear response and buckling loads of the shells. The traditional imperfections include the geometric shell-wall mid-surface imperfections that are commonly discussed in the literature on thin shell buckling, The non-traditional imperfections include shell-wall thickness variations, local shell-wall ply-gaps associated with the fabrication process, shell-end geometric imperfections, non-uniform applied end loads, and variations in the boundary conditions including the effects of elastic boundary conditions. A high-fidelity non-linear shell analysis procedure that accurately accounts for the effects of these traditional and non-traditional imperfections on the non-linear responses and buckling loads of the shells is described. The analysis procedure includes a non-linear static analysis that predicts stable response characteristics of the shells and a non-linear transient analysis that predicts unstable response characteristics. Published by Elsevier Science Ltd. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Hilburger, MW (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 16 TC 42 Z9 45 U1 1 U2 7 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0020-7462 J9 INT J NONLINEAR MECH JI Int. J. Non-Linear Mech. PD JUN-JUL PY 2002 VL 37 IS 4-5 BP 623 EP 643 DI 10.1016/S0020-7462(01)00088-9 PG 21 WC Mechanics SC Mechanics GA 517XL UT WOS:000173635700005 ER PT J AU Nemeth, MP Young, RD Collins, TJ Starnes, JH AF Nemeth, MP Young, RD Collins, TJ Starnes, JH TI Effects of initial geometric imperfections on the non-linear response of the Space Shuttle superlightweight liquid-oxygen tank SO INTERNATIONAL JOURNAL OF NON-LINEAR MECHANICS LA English DT Article ID NONLINEAR BEHAVIOR; LOADS AB The results of an analytical study of the elastic buckling and non-linear behavior of the liquid-oxygen tank for the new Space Shuttle superlightweight external fuel tank are presented. Selected results that illustrate three distinctly different types of non-linear response phenomena for thin-walled shells which are subjected to combined mechanical and thermal loads are presented. These response phenomena consist of a bifurcation-type buckling response, a short-wavelength non-linear bending response, and a non-linear collapse or "snap-through" response associated with a limit point. The effects of initial geometric imperfections on the response characteristics are emphasized. The results illustrate that the buckling and non-linear response of a geometrically imperfect shell structure subjected to complex loading conditions may not be adequately characterized by an elastic linear bifurcation buckling analysis, and that the traditional industry practice of applying a buckling-load knock-down factor can result in an ultra-conservative design. Results are also presented that show that a fluid-filled shell can be highly sensitive to initial geometric imperfections, and that the use a buckling-load knock-down factor is needed for this case. (C) 2002 Published by Elsevier Science Ltd. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Nemeth, MP (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 16 TC 7 Z9 7 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0020-7462 J9 INT J NONLINEAR MECH JI Int. J. Non-Linear Mech. PD JUN-JUL PY 2002 VL 37 IS 4-5 BP 723 EP 744 DI 10.1016/S0020-7462(01)00095-6 PG 22 WC Mechanics SC Mechanics GA 517XL UT WOS:000173635700012 ER PT J AU Vermote, EF Roy, DP AF Vermote, EF Roy, DP TI Land surface hot-spot observed by MODIS over Central Africa SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID REFLECTANCE C1 Univ Maryland, Dept Geog, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Vermote, EF (reprint author), Univ Maryland, Dept Geog, 1113 LeFrak Hall, College Pk, MD 20742 USA. RI Vermote, Eric/K-3733-2012 NR 7 TC 10 Z9 10 U1 0 U2 2 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD JUN PY 2002 VL 23 IS 11 BP 2141 EP 2143 DI 10.1080/01431160110120379 PG 3 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 550PC UT WOS:000175510600001 ER PT J AU Lobell, DB Asner, GP Law, BE Treuhaft, RN AF Lobell, DB Asner, GP Law, BE Treuhaft, RN TI View angle effects on canopy reflectance and spectral mixture analysis of coniferous forests using AVIRIS SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID ARRAY SPECTRORADIOMETER ASAS; BIDIRECTIONAL REFLECTANCE; SATELLITE DATA; VEGETATION; BOREAL; SOILS; VARIABILITY; ANISOTROPY; MODELS; INDEX AB The dependence of vegetation reflectance on sun and sensor geometry can potentially provide information on canopy properties, but also may be a source of unmodelled systematic error in single-angle remote sensing measurements. In this study, we investigated the angular variability of reflectance measurements from the NASA Airborne Visible/Infrared Imaging Spectrometer (AVIRIS), and the resulting impact on spectral mixture analysis (SMA) using both full-range (400-2500 nm) and shortwave-infrared wavelengths (2080-2280 nm; AutoSWIR). The study was conducted in coniferous forests in Central Oregon using five AVIRIS overpasses to generate multiple view angle measurements. Canopy reflectance was highly anisotropic, with the strength of the angular signal controlled by species type, canopy cover and soil reflectance. Canopy cover estimates from full-range SMA averaged only slight decreases (similar to 6% relative) toward the retro-solar direction for 16 field plots in the study region. AutoSWIR was even less influenced by view angle, exhibiting changes only for large differences in view angle. In addition, AutoSWIR's ability to accommodate endmember variability led to stronger agreement with field cover values than full-range SMA. The results suggest that while view angle can significantly affect reflectance measurements from AVIRIS, the consequent variability in vegetation cover estimates from SMA and AutoSWIR is low. C1 Carnegie Inst Washington, Dept Global Ecol, Stanford, CA 94305 USA. Oregon State Univ, Coll Forestry, Corvallis, OR 97331 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lobell, DB (reprint author), Carnegie Inst Washington, Dept Global Ecol, Stanford, CA 94305 USA. EM greg@globalecology.stanford.edu RI Asner, Gregory/G-9268-2013; OI Asner, Gregory/0000-0001-7893-6421; Law, Beverly/0000-0002-1605-1203 NR 36 TC 34 Z9 35 U1 0 U2 8 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD JUN PY 2002 VL 23 IS 11 BP 2247 EP 2262 DI 10.1080/01431160110075613 PG 16 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 550PC UT WOS:000175510600008 ER PT J AU Lemaire, D Bliven, LF Craeye, C Sobieski, P AF Lemaire, D Bliven, LF Craeye, C Sobieski, P TI Drop size effects on rain-generated ring-waves with a view to remote sensing applications SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID WATER SURFACES AB This paper presents an analysis of drop size effects on ring-wave spectra and radar scatterometer returns from a water surface agitated by artificial rain. For this purpose, monodisperse and polydisperse rain events were generated in the laboratory for a wide range of rain rates and various drop sizes. The water droplets reached the surface at terminal velocity. In all cases, the radar average power is well modelled by a linear function of the power spectral density at the Bragg resonant wavelength. The drop size is found to have a strong impact on the spectral shape of the ring-waves and on their total energy. A log-Gaussian model characterizes well the ring-wave spectra and empirical expressions of the spectrum parameters are given. Ring-wave energy increases with rain rate and drop size. and is found to be proportional to the kinetic energy of a single drop, indicating that one may use a model in which all drops contribute to the ring-wave energy in proportion to their squared momentum. The results from the monodisperse rain experiments are used to construct a model for natural rain. Data from the polydisperse rain experiments show that a nonlinear model which relates dissipation to the total rainfall rate provides excellent agreement with the measurements. This analysis also shows the important impact of a few large drops on the ring-wave spectrum. The model proposed can be extended to natural rains either by using measurements of the drop size distribution or by assuming a drop size distribution model that is appropriate to the study region. It is concluded that it is important to characterize ring-wave spectra as a function of rain rate and drop size distribution to develop robust radar scattering models for rain-roughened seas. C1 Univ Catholique Louvain, B-1348 Louvain, Belgium. NASA, Wallops Flight Facil, Lab Hydrospher Proc, Wallops Isl, VA 23337 USA. RP Lemaire, D (reprint author), Univ Catholique Louvain, B-1348 Louvain, Belgium. RI bliven, francis/E-1450-2012 NR 12 TC 18 Z9 18 U1 0 U2 1 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD JUN PY 2002 VL 23 IS 12 BP 2345 EP 2357 DI 10.1080/01431160110107617 PG 13 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 559FB UT WOS:000176014000002 ER PT J AU Bourras, D Eymard, L Liu, WT AF Bourras, D Eymard, L Liu, WT TI A neural network to estimate the latent heat flux over oceans from satellite observations SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID ATMOSPHERIC SURFACE-LAYER; TOGA COARE; WATER; SSM/I; HUMIDITY AB A new method based on a neural network is proposed to infer the mesoscale instantaneous latent heat flux from satellite observations. The new method is compared to the bulk method on a global dataset. The rms error on the estimation of the flux is 35 W m(-2) for the network and is 55 W m(-2) for the bulk method. The estimation error is more variable at mid-latitudes than in the tropics and near the equator. An analysis of the error as a function of environmental conditions shows that the accuracy of satellite derived fluxes is better in low humidity and intermediate to strong wind conditions than in low wind or large humidity conditions. The two methods are validated using three regional datasets. The rms errors on these datasets range from 25 W m(-2) to 45 W m(-2) which is consistent with the results obtained at global scale. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Ctr Etud Environm Terrestre & Planetaires, F-78140 Velizy Villacoublay, France. RP Bourras, D (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 20 TC 12 Z9 12 U1 0 U2 0 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD JUN PY 2002 VL 23 IS 12 BP 2405 EP 2423 DI 10.1080/01431160110070825 PG 19 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 559FB UT WOS:000176014000006 ER PT J AU Banks, HT Joyner, ML Wincheski, B Winfree, WP AF Banks, HT Joyner, ML Wincheski, B Winfree, WP TI Real time computational algorithms for eddy-current-based damage detection SO INVERSE PROBLEMS LA English DT Article ID PROPER ORTHOGONAL DECOMPOSITION; SKIN-EFFECT PROBLEMS; NONDESTRUCTIVE EVALUATION; FLAW DETECTION; PROBE AB In the field of nondestructive evaluation, new and improved techniques are constantly being sought to facilitate the detection of hidden corrosion and flaws in structures such as aeroplanes and pipelines. In this paper, we explore the feasibility of detecting such damage by application of an eddy-current-based technique coupled with reduced order modelling. We begin by developing a model for a specific eddy current method in which we make some simplifying assumptions reducing the three-dimensional problem to a two-dimensional problem (we do this for proof of concept). Theoretical results are then presented which establish the existence and uniqueness of solutions as well as continuous dependence of the solutions on the parameters which represent the damage. We further discuss theoretical issues concerning the least squares parameter estimation problem used in identifying the geometry of the damage. To solve the identification problem, an optimization algorithm is employed which requires solving the forward problem numerous times. To implement these methods in a practical setting, the forward algorithm must be solved with extremely fast and accurate solution methods. In constructing these computational methods, we employ reduced order proper orthogonal decomposition (POD) techniques. This approach permits one to create a set of basis elements spanning a data set consisting of either numerical simulations or experimental data. We discuss two different algorithms for forming the POD approximations, a POD/Galerkin technique and a POD/interpolation technique. Finally, results of the inverse problem associated with damage detection are given using both simulated data with relative noise added as well as experimental data obtained using a giant magnetoresistive sensor. The experimental results are based on successfully using experimental data to form the POD basis elements (instead of numerical simulations), thus illustrating the effectiveness of this method on a wide range of applications. In both instances the methods are found to be efficient and robust. Moreover, the methods were fast; our findings demonstrate a significant reduction in computational time. C1 N Carolina State Univ, Ctr Res Sci COmputat, Raleigh, NC 27695 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Banks, HT (reprint author), N Carolina State Univ, Ctr Res Sci COmputat, Raleigh, NC 27695 USA. NR 52 TC 35 Z9 35 U1 0 U2 8 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0266-5611 J9 INVERSE PROBL JI Inverse Probl. PD JUN PY 2002 VL 18 IS 3 BP 795 EP 823 AR PII S0266-5611(02)26428-X DI 10.1088/0266-5611/18/3/318 PG 29 WC Mathematics, Applied; Physics, Mathematical SC Mathematics; Physics GA 572AB UT WOS:000176750400019 ER PT J AU Boyle, R Highstein, SM Carey, JP Xu, JP AF Boyle, R Highstein, SM Carey, JP Xu, JP TI Functional recovery of anterior semicircular canal afferents following hair cell regeneration in birds SO JARO-JOURNAL OF THE ASSOCIATION FOR RESEARCH IN OTOLARYNGOLOGY LA English DT Article DE vestibular; streptomycin; electrophysiology; biocytin; semicircular canal ID SEVERE ACOUSTIC TRAUMA; AVIAN VESTIBULAR EPITHELIUM; LIGHT-MICROSCOPIC EVIDENCE; MECHANICAL STIMULATION; CRISTAE AMPULLARES; SQUIRREL-MONKEY; CHICK COCHLEA; POSTNATAL-DEVELOPMENT; INNERVATION PATTERNS; GENTAMICIN TREATMENT AB Streptomycin sulfate (1.2 g/kg i.m.) was administered for 5 consecutive days to 5-7-day-old white Leghorn chicks; this causes damage to semicircular canal hair cells that ultimately regenerate to reform the sensory epithelium. During the recovery period, electrophysiological recordings were taken sequentially from anterior semicircular canal primary afferents using an indentation stimulus of the canal that has been shown to mimic rotational stimulation. Chicks were assigned to an early (14-18 days; n = 8), intermediate (28-34 days; n = 5), and late (38-58 days; n = 4) period based on days after treatment. Seven untreated chicks, 15-67 days old, provided control data. An absence of background and indent-induced discharge was the prominent feature of afferents in the early period: only "silent" afferents were encountered in 5/8 experiments. In several of these chicks, fascicles of afferent fibers were seen extending up to the epithelium that was void of hair cells, and intra- and extracellular biocytin labeling revealed afferent processes penetrating into the Supporting Cell layer of the crista. In 3/8 chicks 74 afferents could be characterized, and they significantly differed from controls (n = 130) by having a lower discharge rate and a negligible response to canal stimulation. In the intermediate period there was considerable variability in discharge properties of 121 afferents, but as a whole the number of "silent" fibers in the canal nerve diminished, the background rate increased, and a response to canal stimulation detected. Individually biocytin-labeled afferents had normal-appearing terminal specializations in the sensory epithelium by 28 days poststreptomycin. In the late period, afferents (n = 58) remained significantly different from controls in background discharge properties and response gain. The evidence suggests that a considerable amount of variability exists between chicks in the return of vestibular afferent function following ototoxic injury and that the secretory function of regenerating hair cells might become functional before their transducer function. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Washington Univ, Dept Otolaryngol, St Louis, MO 63110 USA. Washington Univ, Dept Neurobiol, St Louis, MO 63110 USA. Univ Washington, Virginia Merrill Bloedel Hearing Res Ctr, Dept Otolaryngol Head & Neck Surg, Seattle, WA 98195 USA. Oregon Hlth & Sci Univ, Dept Otolaryngol Head Neck Surg, Portland, OR 97201 USA. Oregon Hlth & Sci Univ, Dept Physiol & Pharmacol, Portland, OR 97201 USA. RP Boyle, R (reprint author), NASA, Ames Res Ctr, M-S 239-11, Moffett Field, CA 94035 USA. EM rboyle@mail.arc.nasa.gov FU NIDCD NIH HHS [DC01837, DC02854]; NINDS NIH HHS [NS27050] NR 56 TC 10 Z9 10 U1 0 U2 0 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1525-3961 J9 JARO-J ASSOC RES OTO JI JARO PD JUN PY 2002 VL 3 IS 2 BP 149 EP 166 DI 10.1007/s101620020018 PG 18 WC Neurosciences; Otorhinolaryngology SC Neurosciences & Neurology; Otorhinolaryngology GA 566TB UT WOS:000176443400004 PM 12162365 ER PT J AU Cruden, BA Rao, MVVS Sharma, SP Meyyappan, M AF Cruden, BA Rao, MVVS Sharma, SP Meyyappan, M TI Neutral gas temperature estimates in an inductively coupled CF4 plasma by fitting diatomic emission spectra SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID LASER-INDUCED FLUORESCENCE; INFRARED-ABSORPTION SPECTROSCOPY; DENSITY C4F8 PLASMAS; ROTATIONAL TEMPERATURE; INTENSITY MEASUREMENTS; BAND SYSTEM; ION; DISCHARGES; TRANSITION; MOLECULE AB In this work we examine the accuracy of plasma neutral temperature estimates by fitting the rotational band envelope of different diatomic species in emission. Experiments are performed in an inductively coupled CF4 plasma generated in a Gaseous Electronics Conference reference cell. Visible and ultraviolet emission spectra are collected at a power of 300 W (similar to0.7 W/cm(3)) and pressure of 30 mTorr. The emission bands of several molecules (CF, CN, C-2, CO, and SiF) are fit simultaneously for rotational and vibrational temperatures and compared. Four different rotational temperatures are obtained: 1250 K for CF and CN, 1600 K for CO, 1800 K for C-2, and 2300 K for SiF. The vibrational temperatures obtained vary from 1750 to 5950 K, with the higher vibrational temperatures generally corresponding to the lower rotational temperatures. These results suggest that the different species have achieved different degrees of equilibration between rotational and vibrational modes and may not be equilibrated with the translational temperatures. The different temperatures also appear to relate to the expected spacial distribution of the molecules, with species expected to form near the electrode (C-2, CO, SiF) having higher temperatures than species formed in the bulk. (C) 2002 American Institute of Physics. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Eloret Corp, Sunnyvale, CA USA. RP Cruden, BA (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 38 TC 53 Z9 54 U1 0 U2 9 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 2002 VL 91 IS 11 BP 8955 EP 8964 DI 10.1063/1.1474614 PG 10 WC Physics, Applied SC Physics GA 553ZU UT WOS:000175708900004 ER PT J AU Gage, K Hardesty, M May, P Browell, E AF Gage, K Hardesty, M May, P Browell, E TI Tropospheric profiling - Preface SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Editorial Material C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. NOAA, Environm Technol Lab, Boulder, CO USA. BMRC, Melbourne, Vic, Australia. NASA, Langley Res Ctr, Langley, VA USA. RP Gage, K (reprint author), NOAA, Aeron Lab, 325 Broadway, Boulder, CO 80303 USA. RI Hardesty, Robert/H-9844-2013 NR 2 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD JUN PY 2002 VL 19 IS 6 BP 833 EP 833 DI 10.1175/1520-0426(2002)019<0833:PP>2.0.CO;2 PG 1 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 557GZ UT WOS:000175901900001 ER PT J AU Petersen, WA Nesbitt, SW Blakeslee, RJ Cifelli, R Hein, P Rutledge, SA AF Petersen, WA Nesbitt, SW Blakeslee, RJ Cifelli, R Hein, P Rutledge, SA TI TRMM observations of intraseasonal variability in convective regimes over the Amazon SO JOURNAL OF CLIMATE LA English DT Article ID ICE-SCATTERING SIGNATURE; SOUTH-AMERICA; SQUALL LINES; LIGHTNING OBSERVATIONS; TOGA COARE; RADAR; RAINFALL; SYSTEMS; ALGORITHM; INTENSITY AB This study utilizes the Tropical Rainfall Measuring Mission (TRMM) satellite precipitation radar (PR), lightning imaging sensor (LIS), and passive microwave imager (TMI) data together with ground-based lightning data to investigate the vertical structure, lightning, and rainfall characteristics of Amazonian and subtropical South American convection for three separate wet seasons. These characteristics are partitioned as a function of 850-mb zonal wind direction, motivated by observations collected during the 6-week TRMM-Large-scale Biosphere-Atmosphere Experiment in Amazonia (LBA) field campaign. The TRMM-LBA field campaign observations suggest that systematic variations in Amazonian convective vertical structure, lightning, and rainfall are all linked to bimodal variations in the low-level zonal wind (e. g., easterly and westerly regimes). The more spatially and temporally comprehensive TRMM dataset used in this study extends the TRMM-LBA observations by examining regime variability in Amazonian and South American convective structure over a continental-scale domain. On a continental scale, patterns of east and west regime 850-700-mb winds combined with LIS lightning flash densities suggest the presence of synoptic-scale controls [e. g., intrusion of extratropical frontal systems and interaction with the South Atlantic Convergence Zone (SACZ)] on regional-scale variability in convective vertical structure. TRMM PR, TMI, and ground-based lightning data suggest that regional variability in wet-season convective structure is most evident over the southern Amazon, Mato Grosso, Altiplano, southern Brazil, and eastern coastal regions of central and southern South America. Convective vertical structure, convective rainfall rates, and lightning activity are all more pronounced during easterly (westerly) regimes over the southern Amazon and Mato Grosso (Altiplano, and southern Brazil). Importantly, when considered with case study results from TRMM-LBA, the systematic differences in convective structure that occur as a function of regime suggest that associated regime differences may exist in the vertical distribution of diabatic heating. Hence the discrimination of convective vertical structure "regimes'' over parts of the Amazon and vicinity based on a resolved variable such as the 850-700-mb zonal wind direction, while far from being perfect, may have important applications to the problems of cumulus parameterization, rainfall estimation, and retrievals of latent heating over the Amazon. C1 Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. Univ Utah, Dept Meteorol, Salt Lake City, UT 84112 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Petersen, WA (reprint author), Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. RI Nesbitt, Stephen/I-3965-2013 OI Nesbitt, Stephen/0000-0003-0348-0452 NR 54 TC 82 Z9 85 U1 0 U2 7 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD JUN 1 PY 2002 VL 15 IS 11 BP 1278 EP 1294 DI 10.1175/1520-0442(2002)015<1278:TOOIVI>2.0.CO;2 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 547UC UT WOS:000175349600003 ER PT J AU Loeb, NG Kato, S AF Loeb, NG Kato, S TI Top-of-atmosphere direct radiative effect of aerosols over the tropical oceans from the Clouds and the Earth's Radiant Energy System (CERES) satellite instrument SO JOURNAL OF CLIMATE LA English DT Article ID ANGULAR-DISTRIBUTION MODELS; OPTICAL-PROPERTIES; TROPOSPHERIC AEROSOLS; ALBEDO ESTIMATION; BOUNDARY-LAYER; IDENTIFICATION; REFLECTANCE; CLOUDINESS; RETRIEVALS; VALIDATION AB Nine months of the Clouds and the Earth's Radiant Energy System (CERES)/Tropical Rainfall Measuring Mission (TRMM) broadband fluxes combined with the TRMM visible infrared scanner (VIRS) high-resolution imager measurements are used to estimate the daily average direct radiative effect of aerosols for clear-sky conditions over the tropical oceans. On average, aerosols have a cooling effect over the Tropics of 4.6+/-1 W m(-2). The magnitude is approximate to2 W m 22 smaller over the southern tropical oceans than it is over northern tropical oceans. The direct effect derived from CERES is highly correlated with coincident aerosol optical depth (tau) retrievals inferred from 0.63-mum VIRS radiances (correlation coefficient of 0.96). The slope of the regression line is approximate to -32 W m(-2) tau(-1) over the equatorial Pacific Ocean, but changes both regionally and seasonally, depending on the aerosol characteristics. Near sources of biomass burning and desert dust, the aerosol direct effect reaches -25 to -30 W m(-2). The direct effect from CERES also shows a dependence on wind speed. The reason for this dependence is unclear-it may be due to increased aerosol (e. g., sea-salt or aerosol transport) or increased surface reflection (e. g., due to whitecaps). The uncertainty in the tropical average direct effect from CERES is approximate to1 W m(-2) (approximate to20%) due mainly to cloud contamination, the radiance-to-flux conversion, and instrument calibration. By comparison, uncertainties in the direct effect from the Earth Radiation Budget Experiment (ERBE) and CERES "ERBE-like'' products are a factor of 3-5 times larger. C1 Hampton Univ, Ctr Atmospher Sci, Hampton, VA 23668 USA. RP Loeb, NG (reprint author), NASA, Langley Res Ctr, Mail Stop 420, Hampton, VA 23681 USA. NR 47 TC 66 Z9 67 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 JUN PY 2002 VL 15 IS 12 BP 1474 EP 1484 DI 10.1175/1520-0442(2002)015<1474:TOADRE>2.0.CO;2 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 552UM UT WOS:000175638500007 ER PT J AU Dyson, RW AF Dyson, RW TI Technique for very high order nonlinear simulation and validation SO JOURNAL OF COMPUTATIONAL ACOUSTICS LA English DT Article DE spectral; resolution; aeroacoustics; MESA; hermitian; Euler equations; small stencil; efficient propagation ID BOUNDARY-CONDITIONS; HYPERBOLIC SYSTEMS; HIGH-ACCURACY; EQUATIONS; CODES; SOUND AB Finding the sources of sound in large nonlinear fields via direct simulation currently requires excessive computational cost. This paper describes a simple technique for efficiently solving the multidimensional nonlinear Euler equations that significantly reduces this cost and demonstrates a useful approach for validating high order nonlinear methods. Up to 15th order accuracy in space and time methods were compared and it is shown that an algorithm with a fixed design accuracy approaches its maximal utility and then its usefulness exponentially decays unless higher accuracy is used. It is concluded that at least a 7th order method is required to efficiently propagate a harmonic wave using the nonlinear Euler equations to a distance of five wavelengths while maintaining an overall error tolerance that is low enough to capture both the mean flow and the acoustics. C1 NASA, Glenn Res Ctr, Cleveland, OH 44035 USA. RP Dyson, RW (reprint author), NASA, Glenn Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44035 USA. NR 35 TC 8 Z9 8 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 0218-396X J9 J COMPUT ACOUST JI J. Comput. Acoust. PD JUN PY 2002 VL 10 IS 2 BP 211 EP 229 DI 10.1142/S0218396X02001553 PG 19 WC Acoustics; Mathematics, Interdisciplinary Applications SC Acoustics; Mathematics GA 571XZ UT WOS:000176745600004 ER PT J AU Hazeltine, E Teague, D Ivry, RB AF Hazeltine, E Teague, D Ivry, RB TI Simultaneous dual-task performance reveals parallel response selection after practice SO JOURNAL OF EXPERIMENTAL PSYCHOLOGY-HUMAN PERCEPTION AND PERFORMANCE LA English DT Article ID EXECUTIVE COGNITIVE-PROCESSES; COMPUTATIONAL THEORY; DIVIDED ATTENTION; INTERFERENCE; BOTTLENECKS; POSTPONEMENT; MECHANISMS; LOCUS AB E. H. Schumacher, T. L. Seymour, J. M. Glass, D. E. Kieras, and D. E. Meyer (2001) reported that dual-task costs are minimal when participants are practiced and give the 2 tasks equal emphasis. The present research examined whether such findings are compatible with the operation of an efficient response selection bottleneck. Participants trained until they were able to perform both tasks simultaneously without interference. Novel stimulus pairs produced no reaction time costs, arguing against the development of compound stimulus-response associations (Experiment 1). Manipulating the relative onsets (Experiments 2 and 4) and durations (Experiments 3 and 4) of response selection processes did not lead to dual-task costs. The results indicate that the 2 tasks did not share a bottleneck after practice. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Calif Berkeley, Dept Psychol, Berkeley, CA 94720 USA. RP Hazeltine, E (reprint author), NASA, Ames Res Ctr, Mail Stop 262-4, Moffett Field, CA 94035 USA. FU NINDS NIH HHS [NS1778, NS30256] NR 31 TC 117 Z9 117 U1 0 U2 4 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 JUN PY 2002 VL 28 IS 3 BP 527 EP 545 DI 10.1037//0096-1523.28.3.527 PG 19 WC Psychology; Psychology, Experimental SC Psychology GA 559AH UT WOS:000176001600003 PM 12075886 ER PT J AU Bogaert, J Zhou, L Tucker, CJ Myneni, RB Ceulemans, R AF Bogaert, J Zhou, L Tucker, CJ Myneni, RB Ceulemans, R TI Evidence for a persistent and extensive greening trend in Eurasia inferred from satellite vegetation index data SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE NDVI; global warming; greening; spatial pattern; AVHRR ID LANDSCAPE PATTERN; ATMOSPHERIC CO2; SHAPE COMPACTNESS; CLIMATE-CHANGE; UNITED-STATES; FRAGMENTATION; PERIMETER; METRICS; STATISTICS; LATITUDES AB [1] The northern latitudes have warmed by similar to0.8degreesC since the early 1970s, but not all areas have warmed equally. Eurasia shows an overall warming trend, while North America exhibits warming at a lower rate and even a slight cooling trend during the last 50 years in the eastern United States. We analyzed a recently developed satellite normalized difference vegetation index (NDVI) data set (July 1981 to December 1999) to assess vegetation response to these temperature changes. An index of persistence of the NDVI trend was used to generate patches of different levels of persistence. The persistence data were analyzed for patch area, patch perimeter, patch number, patch coherence, largest patch size, patch fragmentation, pixel contiguity, pixel clustering, and conditional probability of pixel adjacency. We address two questions: (1) Is there a difference in the spatial pattern of long-term NDVI increase in comparison to short-term increase? and (2) Are there differences in the spatial patterns of patches between Eurasia and North America? The results indicate a persistent and spatially extensive and connected greening trend in Eurasia, relative to North America. The regions showing short-term greening in Eurasia show a scattered pattern of spatially remote small patches. In North America the long-term greening pattern is spatially fragmented, and a mixture of short-and long-term NDVI increase is found, unlike in Eurasia. Therefore we conclude that the greening trend in Eurasia is more persistent and spatially extensive than in North America, which is qualitatively consistent with near-surface air temperature observations. C1 Boston Univ, Dept Geog, Boston, MA 02215 USA. Univ Antwerp, Dept Biol, B-2610 Wilrijk, Belgium. NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. RP Bogaert, J (reprint author), Boston Univ, Dept Geog, 675 Commonwealth Ave, Boston, MA 02215 USA. RI Zhou, Liming/A-2688-2012; Myneni, Ranga/F-5129-2012; Ceulemans, Reinhart/F-2109-2016 NR 60 TC 33 Z9 36 U1 1 U2 13 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0747-7309 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN PY 2002 VL 107 IS D11 AR 4119 DI 10.1029/2001JD001075 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 609HN UT WOS:000178897700014 ER PT J AU Kaufmann, RK Zhou, L Tucker, CJ Slayback, D Shabanov, NV Myneni, RB AF Kaufmann, RK Zhou, L Tucker, CJ Slayback, D Shabanov, NV Myneni, RB TI Reply to Comment on "Variations in northern vegetation activity inferred from satellite data of vegetation index during 1981-1999'' by J. R. Ahlbeck SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Editorial Material DE NDVI; climate; temperature; CO2; fertilization C1 Boston Univ, Dept Geog, Boston, MA 02215 USA. NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Sci Syst & Applicat Inc, Greenbelt, MD 20771 USA. RP Kaufmann, RK (reprint author), Boston Univ, Dept Geog, 675 Commonwealth Ave, Boston, MA 02215 USA. RI Slayback, Daniel/E-7465-2011; Zhou, Liming/A-2688-2012; Myneni, Ranga/F-5129-2012 NR 4 TC 5 Z9 5 U1 0 U2 13 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0747-7309 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN PY 2002 VL 107 IS D11 AR 4127 DI 10.1029/2001JD001516 PG 3 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 609HN UT WOS:000178897700006 ER PT J AU Li, SH Cordero, EC Karoly, DJ AF Li, SH Cordero, EC Karoly, DJ TI Transport out of the Antarctic polar vortex from a three-dimensional transport model SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE transport; polar vortex; mass flux; dilution effect ID METEOROLOGYS GLOBAL ASSIMILATION; SHAPE-PRESERVING INTERPOLATION; GENERAL-CIRCULATION MODEL; SEMI-LAGRANGIAN TRANSPORT; TOTAL OZONE; POTENTIAL VORTICITY; LOWER STRATOSPHERE; PREDICTION SYSTEM; MIDDLE ATMOSPHERE; BREAKING AB [1] A three-dimensional chemical transport model is utilized to study the transport out of the Antarctic polar vortex during the southern hemisphere spring. On average, over five consecutive years between 1993 and 1997, horizontal transport out of the vortex into the midlatitude stratosphere is smaller than vertical transport into the troposphere. However, there is significant interannual variability in the magnitude of mass exchange, which is related to year-to-year fluctuations in planetary wave activity. In 1994 the net loss of the vortex tracer mass in September is similar to that in October. However, the relative mass flux entering the midlatitude stratosphere and the troposphere differ between the two months. The ratio of horizontal transport out of the vortex to vertical transport into the troposphere is about 3: 7 in September and 5: 5 in October, indicating the higher permeability of the vortex in October compared to September. The September mass flux into the troposphere is larger than in October, consistent with the fact that stronger diabatic cooling occurs in September than October over Antarctica. The estimated ozone change at southern midlatitudes due to the intrusion of ozone-depleted air from high latitudes during September-October 1994 is about 0.44% per decade, which could contribute up to 10% of observed ozone decline at southern midlatitudes in spring. This amount is an underestimate of the dilution effect from high latitudes during the spring season, as it does not include the vortex breakup in late spring. C1 Monash Univ, Sch Math Sci, Clayton, Vic 3800, Australia. RP Li, SH (reprint author), NASA, Goddard Space Flight Ctr, UMBC, Goddard Earth Sci & Technol Ctr, Code 910-4, Greenbelt, MD 20771 USA. RI Karoly, David/C-8262-2011 OI Karoly, David/0000-0002-8671-2994 NR 43 TC 6 Z9 6 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0747-7309 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN PY 2002 VL 107 IS D11 AR 4132 DI 10.1029/2001JD000508 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 609HN UT WOS:000178897700001 ER EF