23 results on '"Wilson, J. C"'
Search Results
2. Paired donor interchange to avoid ABO-incompatible living donor liver transplantation
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Boon Hun Yong, Kelvin K. Ng, See Ching Chan, Sheung Tat Fan, Wilson J. C. Tsui, and Chung Mau Lo
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Transplantation ,medicine.medical_specialty ,Hepatology ,business.industry ,medicine.medical_treatment ,Immunosuppression ,Liver transplantation ,medicine.disease ,Surgery ,Spontaneous bacterial peritonitis ,medicine.anatomical_structure ,ABO blood group system ,medicine ,Abdomen ,Living donor liver transplantation ,business ,Kidney transplantation - Abstract
We report an emergency paired donor interchange living donor liver transplant performed on January 13, 2009. The 4 operations (2 liver transplants) were performed simultaneously. The aim was to avoid 2 ABO-incompatible liver transplants. One recipient in acute liver failure underwent transplantation in a high-urgency situation. The abdomen of the other recipient had severe adhesions from previous spontaneous bacterial peritonitis that rendered the recipient operation almost impossible. The ethical and logistical issues are discussed. Approaches adopted in anticipation of potential adverse outcomes are explained in view of the higher donor and recipient mortality and morbidity rates in comparison with kidney transplantation.
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- 2010
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3. Bioavailable testosterone is associated with a reduced risk of amnestic mild cognitive impairment in older men
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Ping-Yiu Yik, Bernard M.Y. Cheung, Wilson J. C. Tsui, You-Qiang Song, Sidney Tam, Leung-Wing Chu, John E. Morley, Rachel L.C. Wong, Peter W. H. Lee, and Karen S.L. Lam
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Male ,medicine.medical_specialty ,Cross-sectional study ,Endocrinology, Diabetes and Metabolism ,Biological Availability ,Lower risk ,behavioral disciplines and activities ,Cognition ,Endocrinology ,Alzheimer Disease ,Risk Factors ,Internal medicine ,mental disorders ,medicine ,Humans ,Testosterone ,Risk factor ,Stroke ,Aged ,Aged, 80 and over ,business.industry ,Cognitive disorder ,Odds ratio ,Middle Aged ,medicine.disease ,Confidence interval ,Cross-Sectional Studies ,Alzheimer's disease ,Cognition Disorders ,business - Abstract
Summary Objective We investigated the risk of amnestic mild cognitive impairment (aMCI) in relation to serum bioavailable (BT) and total testosterone (TT) levels in older men. Design, setting and subjects A cross-sectional study in an ambulatory setting, with older men aged 55–93 years with normal cognition, aMCI and Alzheimer's disease (AD). Measurements Morning serum BT and TT levels were determined. AD was diagnosed by the Neurological and Communicative Disorders and Stroke/Alzheimer's Disease and Related Disorders Association (NINCDS-ADRDA) criteria for probable AD and aMCI by the Petersen criteria. Results We recruited 203 Chinese older men (48 aMCI, 66 AD and 89 with normal cognition). Mean serum BT, but not TT, levels were significantly lower in the aMCI (mean BT ± SEM 1·06 ± 0·10 nmol/l) and AD (0·99 ± 0·08 nmol/l) groups than in the normal controls (1·82 ± 0·12 nmol/l) (P
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- 2008
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4. Psychological Assessment of Recipients and Donors in Liver Transplantation
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Lina Y.F. Wu, Damaris S.M. Hung, Amy S. M. Fung, Wilson J. C. Tsui, Peter Wh H. Lee, and Brenda S.B. Lam
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medicine.medical_specialty ,business.industry ,Internal medicine ,medicine.medical_treatment ,medicine ,Psychological testing ,Liver transplantation ,business - Published
- 2011
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5. Aerosols in the tropical and subtropical UT/LS: in-situ measurements of submicron particle abundance and volatility
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Borrmann, Stephan, Kunkel, Daniel, Weigel, Ralf, Minikin, Andreas, Deshler, Terry, Wilson, J. C., Curtius, Joachim, Shur, G., Belyaev, D., Law, K. S., and Cairo, F.
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010504 meteorology & atmospheric sciences ,13. Climate action ,aerosol ,ddc:550 ,Atmosphärische Spurenstoffe ,AMMA ,010502 geochemistry & geophysics ,UT/LS ,01 natural sciences ,TROCCINOX ,0105 earth and related environmental sciences - Abstract
Processes occurring in the tropical upper troposphere and lower stratosphere (UT/LS) are of importance for the global climate, for the stratospheric dynamics and air chemistry, and they influence the global distribution of water vapour, trace gases and aerosols. The mechanisms underlying cloud formation and variability in the UT/LS are of scientific concern as these still are not adequately described and quantified by numerical models. Part of the reasons for this is the scarcity of detailed in-situ measurements in particular from the Tropical Transition Layer (TTL) within the UT/LS. In this contribution we provide measurements of particle number densities and the amounts of non-volatile particles in the submicron size range present in the UT/LS over Southern Brazil, West Africa, and Northern Australia. The data were collected in-situ on board of the Russian high altitude research aircraft M-55 "Geophysica" using the specialised COPAS (COndensation PArticle counting System) instrument during the TROCCINOX (Araçatuba, Brazil, February 2005), the SCOUT-O3 (Darwin, Australia, December 2005), and SCOUT-AMMA (Ouagadougou, Burkina Faso, August 2006) campaigns. The vertical profiles obtained are compared to those from previous measurements from the NASA DC-8 and NASA WB-57F over Costa Rica and other tropical locations between 1999 and 2007. The number density of the submicron particles as function of altitude was found to be remarkably constant (even back to 1987) over the tropical UT/LS altitude band such that a parameterisation suitable for models can be extracted from the measurements. At altitudes corresponding to potential temperatures above 430 K a slight increase of the number densities from 2005/2006 results from the data in comparison to the 1987 to 2007 measurements. The origins of this increase are unknown. By contrast the data from Northern hemispheric mid latitudes do not exhibit such an increase between 1999 and 2006. Vertical profiles of the non-volatile fraction of the submicron particles were also measured by a COPAS channel and are presented here. The resulting profiles of the non-volatile number density fraction show a pronounced maximum of 50% in the tropical TTL over Australia and West Africa. Below and above this fraction is much lower attaining values of 10% and smaller. In the lower stratosphere the fine particles mostly consist of sulphuric acid which is reflected in the low numbers of non-volatile residues measured by COPAS. Without detailed chemical composition measurements the reason for the increase of non-volatile particle fractions cannot yet be given. The long distance transfer flights to Brazil, Australia and West-Africa were executed during a time window of 17 months within a period of relative volcanic quiescence. Thus the data measured during these transfers represent a "snapshot picture" documenting the status of a significant part of the global UT/LS aerosol (with sizes below 1 μm) at low concentration levels 15 years after the last major (i.e., the 1991 Mount Pinatubo) eruption. The corresponding latitudinal distributions of the measured particle number densities are also presented in this paper in order to provide input on the UT/LS background aerosol for modelling purposes.
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- 2009
6. Characterizing Young Brown Dwarfs using Low Resolution Near-IR Spectra
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Allers, K. N., Jaffe, D. T., Luhman, K. L., Liu, Michael C., Wilson, J. C., Skrutskie, M. F., Nelson, M., Peterson, D. E., Smith, J. D., and Cushing, M. C.
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Astrophysics (astro-ph) ,Astrophysics::Solar and Stellar Astrophysics ,FOS: Physical sciences ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics ,Astrophysics::Galaxy Astrophysics - Abstract
We present near-infrared (1.0-2.4 micron) spectra confirming the youth and cool effective temperatures of 6 brown dwarfs and low mass stars with circumstellar disks toward the Chamaeleon II and Ophiuchus star forming regions. The spectrum of one of our objects indicates that it has a spectral type of ~L1, making it one of the latest spectral type young brown dwarfs identified to date. Comparing spectra of young brown dwarfs, field dwarfs, and giant stars, we define a 1.49-1.56 micron H2O index capable of determining spectral type to within 1 sub-type, independent of gravity. We have also defined an index based on the 1.14 micron sodium feature that is sensitive to gravity, but only weakly dependent on spectral type for field dwarfs. Our 1.14 micron Na index can be used to distinguish young cluster members (t, Comment: 11 pages, Accepted to ApJ
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- 2006
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7. A Spitzer Infrared Spectrograph (IRS) Spectral Sequence of M, L, and T Dwarfs
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Cushing, M. C., Roellig, T. L., Marley, M. S., Saumon, D., Leggett, S. K., Kirkpatrick, J. D., Wilson, J. C., Sloan, G. C., Mainzer, A. K., Van Cleve, J. E., and Houck, J. R.
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Astrophysics (astro-ph) ,Astrophysics::Solar and Stellar Astrophysics ,FOS: Physical sciences ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Astrophysics::Galaxy Astrophysics - Abstract
We present a low-resolution (R = 90), 5.5-38 micron spectral sequence of a sample of M, L, and T dwarfs obtained with the Infrared Spectrograph (IRS) onboard the Spitzer Space Telescope. The spectra exhibit prominent absorption bands of H_2O at 6.27 microns, CH_4 at 7.65 microns, and NH_3 at 10.5 microns and are relatively featureless at lambda > 15 microns. Three spectral indices that measure the strengths of these bands are presented; H_2O absorption features are present throughout the MLT sequence while the CH_4 and NH_3 bands first appear at roughly the L/T transition. Although the spectra are, in general, qualitatively well matched by synthetic spectra that include the formation of spatially homogeneous silicate and iron condensate clouds, the spectra of the mid-type L dwarfs show an unexpected flattening from roughly 9 to 11 microns. We hypothesize that this may be a result of a population of small silicate grains that are not predicted in the cloud models. The spectrum of the peculiar T6 dwarf 2MASS J0937+2931 is suppressed from 5.5-7.5 microns relative to typical T6 dwarfs and may be a consequence of its mildly metal-poor/high surface gravity atmosphere. Finally, we compute bolometric luminosities of a subsample of the M, L, and T dwarfs by combining the IRS spectra with previously published 0.6-4.1 micron spectra and find good agreement with the values of Golimowski et al. who use L'- and M'-band photometry and to account for the flux emitted at lambda > 2.5 microns., Accepted for publication in the Astrophysical Journal
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- 2006
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8. The Antennae Ultraluminous X-Ray Source, X-37, Is A Background Quasar
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Clark, D. M., Christopher, M. H., Eikenberry, S. S., Brandl, B. R., Wilson, J. C., Carson, J. C., Henderson, C. P., Hayward, T. L., Barry, D. J., Ptak, A. F., and Colbert, E. J. M.
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Astrophysics::High Energy Astrophysical Phenomena ,Astrophysics (astro-ph) ,Astrophysics::Solar and Stellar Astrophysics ,FOS: Physical sciences ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Astrophysics::Galaxy Astrophysics - Abstract
In this paper we report that a bright, X-ray source in the Antennae galaxies (NGC 4038/9), previously identified as an ultra-luminous X-ray source, is in fact a background quasar. We identify an isolated infrared and optical counterpart within 0.3+/-0.5 arcseconds the X-ray source X-37. After acquiring an optical spectrum of its counterpart, we use the narrow [OIII] and broad H_alpha emission lines to identify X-37 as a quasar at a redshift of z=0.26. Through a U, V, and K_s photometric analysis, we demonstrate that most of the observable light along this line of sight is from the quasar. We discuss the implications of this discovery and the importance of acquiring spectra for optical and IR counterparts to ULXs., Comment: 11 pages, 3 Postscript figures, accepted by ApJL
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- 2005
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9. Infrared Observations of the Candidate LBV 1806-20 & Nearby Cluster Stars
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Eikenberry, S. S., Matthews, K., LaVine, J. L., Garske, M. A., Hu, D., Jackson, M. A., Patel, S. G., Barry, D. J., Colonno, M. R., Houck, J. R., Wilson, J. C., Corbel, S., and Smith, J. D.
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Astrophysics (astro-ph) ,FOS: Physical sciences - Abstract
We report near-infrared photometry, spectroscopy, and speckle imaging of the hot, luminous star we identify as candidate LBV 1806-20. We also present photometry and spectroscopy of 3 nearby stars, which are members of the same star cluster containing LBV 1806-20 and SGR 1806-20. The spectroscopy and photometry show that LBV 1806-20 is similar in many respects to the luminous ``Pistol Star'', albeit with some important differences. They also provide estimates of the effective temperature and reddening of LBV 1806-20, and confirm distance estimates, leading to a best estimate for the luminosity of this star of $> 5 \times 10^6 L_{\odot}$. The nearby cluster stars have spectral types and inferred absolute magnitudes which confirm the distance (and thus luminosity) estimate for LBV 1806-20. If we drop kinematic measurements of the distance ($15.1 ^{+1.8}_{-1.3}$ kpc), we have a lower limit on the distance of $>9.5$ kpc, and on the luminosity of $>2 \times 10^6 L_{\odot}$, based on the cluster stars. If we drop both the kinematic and cluster star indicators for distance, an ammonia absorption feature sets yet another lower limit to the distance of $>5.7$ kpc, with a corresponding luminosity estimate of $>7 \times 10^5 L_{\odot}$ for the candidate LBV 1806-20. Furthermore, based on very high angular-resolution speckle images, we determine that LBV 1806-20 is not a cluster of stars, but is rather a single star or binary system. Simple arguments based on the Eddington luminosity lead to an estimate of the total mass of LBV 1806-20 (single or binary) exceeding $190 M_{\odot}$. We discuss the possible uncertainties in these results, and their implications for the star formation history of this cluster., 36 pages, including 8 figures (Figures 1 and 7 in JPG format due to space); Accepted for publication in ApJ
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- 2004
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10. Spitzer Infrared Spectrograph Observations of M, L, and T Dwarfs
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Roellig, T. L., Van Cleve, J. E., Sloan, G. C., Wilson, J. C., Saumon, D., Leggett, S. K., Marley, M. S., Cushing, M. C., Kirkpatrick, J. D., Mainzer, A. K., and Houck, J. R.
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Astrophysics (astro-ph) ,Astrophysics::Solar and Stellar Astrophysics ,FOS: Physical sciences ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics ,Astrophysics::Galaxy Astrophysics - Abstract
We present the first mid-infrared spectra of brown dwarfs, together with observations of a low-mass star. Our targets are the M3.5 dwarf GJ 1001A, the L8 dwarf DENIS-P J0255-4700, and the T1/T6 binary system epsilon Indi Ba/Bb. As expected, the mid-infrared spectral morphology of these objects changes rapidly with spectral class due to the changes in atmospheric chemistry resulting from their differing effective temperatures and atmospheric structures. By taking advantage of the unprecedented sensitivity of the Infrared Spectrograph on the Spitzer Space Telescope we have detected the 7.8 micron methane and 10 micron ammonia bands for the first time in brown dwarf spectra., Comment: 4 pages, 2 figures
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- 2004
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11. Aircraft Particle Inlets - State-of-the-Art and Future Needs
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Manfred Wendisch, Coe, H., Baumgardner, D., Brenguier, J. -L, Dreiling, V., Fiebig, M., Formenti, P., Hermann, M., Krämer, M., Levin, Z., Maser, R., Mathieu, E., Nacass, P., Noone, K., Osborne, S., Schneider, J., Schütz, L., Schwarzenböck, A., Stratmann, F., Wilson, J. C., Leipziger Institut für Meteorologie (LIM), Universität Leipzig, School of Earth, Atmospheric and Environmental Sciences [Manchester] (SEAES), University of Manchester [Manchester], Centro de Ciencias de la Atmosfera [Mexico], Universidad Nacional Autónoma de México = National Autonomous University of Mexico (UNAM), Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Flight Facilities, Norwegian Institute for Air Research (NILU), Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Helmholtz zentrum für Schwerionenforschung GmbH (GSI), enviscope GmbH, Centre de recherche sur les Risques et les Crises (CRC), Mines Paris - PSL (École nationale supérieure des mines de Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), International Geosphere Biosphere Program, Leibniz Institute for Tropospheric Research (TROPOS), Institut für Meteorologie [Leipzig] (LIM), Universität Leipzig [Leipzig], Universidad Nacional Autónoma de México (UNAM), Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), PSL Research University (PSL)-MINES ParisTech - École nationale supérieure des mines de Paris, Météofrance, Météo France, MINES ParisTech - École nationale supérieure des mines de Paris, Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)
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[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere ,AND STRATMANN- Manfred Wendisch ,ddc:550 ,HERMANN ,AFFILIATIONS: WENDISCH ,PermoserstraBe ,ComputingMilieux_MISCELLANEOUS ,Leibnizlnstitut fur Tropospharenforschung e.V. (IfT) - Abstract
International audience; Experts discussed how to get aerosol particles into airborne instruments without changing their ambient properties-a still unresolved problem.
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- 2004
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12. CORMASS: A Compact and Efficient NIR Spectrograph for Studying Low-Mass Objects
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Wilson, J. C., Skrutskie, M. F., Colonno, M. R., Enos, A. T., Smith, J. D., Henderson, C. P., Gizis, J. E., Monet, D. G., and Houck, J. R.
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Astrophysics (astro-ph) ,Astrophysics::Instrumentation and Methods for Astrophysics ,Astrophysics::Solar and Stellar Astrophysics ,FOS: Physical sciences ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Astrophysics::Galaxy Astrophysics - Abstract
CorMASS (Cornell Massachusetts Slit Spectrograph) is a compact, low-resolution (R=300), double-pass prism cross-dispersed near-infrared (NIR) spectrograph in operation on the Palomar Observatory 60-inch telescope. Its 2-dimensional spectral format provides simultaneous coverage from lambda ~ 0.75 microns to lambda ~ 2.5 microns (z'JHK bands). A remotely operated cold flip mirror permits its NICMOS3 detector to function as a K_s slit viewer to assist object placement into the 2 arcsec x 15 arcsec slit. CorMASS was primarily designed for the rapid spectral classification of low-mass stellar and sub-stellar objects identified by the Two-Micron All Sky Survey (2MASS). CorMASS' efficiency and resolution also make it a versatile instrument for the spectral observation and classification of many other types of bright objects (K, To be published in Feb 2001 PASP, 19 pages, 12 Figures, High Resolution file can be retrieved from ftp://iras2.tn.cornell.edu/pub/wilson/papers/cormass.ps.gz
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- 2000
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13. The reliability and validity of the Alzheimer's diseases assessment scale cognitive subscale (ADAS-COG) among chinese elderly people in Hong Kong
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Wilson J. C. Tsui, Peter W. H. Lee, Patrick Kc Chiu, Sau Lan Hui, and Leung-Wing Chu
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Gerontology ,Aging ,business.industry ,General Neuroscience ,Cognition ,Assessment scale ,Adas cog ,Medicine ,Elderly people ,Neurology (clinical) ,Geriatrics and Gerontology ,business ,Reliability (statistics) ,Developmental Biology - Published
- 2000
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14. Proposed New Combination of Propellers for Ships of War
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Quick, George and Wilson, J. C.
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Engineering ,business.industry ,Political Science and International Relations ,business ,Marine engineering - Abstract
n/a
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- 1876
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15. PATHOLOGICAL SOCIETY OF PHILADELPHIA.: Stated Meeting, March 25th, 1886
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Wilson, J. C.
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n/a
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- 1886
16. Discussion. On the Aba-El-Wakf Sugar Factory, Upper Egypt
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Anderson, W., Wilson, J. C., Alleyne, Sir J., Phillips, G., Siemens, C. W., Beanes, E., Knaggs, W., Helpin, D., Dixon, J., Ogston, G. H., Letherby, H., Rich, W. E., Cowper, E. A., Alliott, J. B., and Godsman, J. G. C. C.
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n/a
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- 1872
17. Seamen of the Fleet, Their Training, and How the Employment of Marines Afloat in Peace Time Affects Them
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Wilson, J. C.
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n/a
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- 1874
18. PATHOLOGICAL SOCIETY OF PHILADELPHIA.: Stated Meeting, January 14, 1886
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Wilson, J. C.
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n/a
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- 1886
19. Is our Merchant Service Any Longer a Feeder to the Royal Navy?
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Wilson, J. C.
- Abstract
n/a
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- 1876
20. Dusty Disks, Diffuse Clouds, and Dim Suns - Galactic Science with the Infrared Spectrograph on the Spitzer Space Telescope
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Roellig, T. L., Dan Watson, Uchida, K. I., Forrest, W. J., Cleve, J. E., Herter, T. L., Sloan, G. C., Furlan, E., Wilson, J. C., Bernard-Salas, J., Saumon, D., Leggett, S., Chen, C., Kemper, F., Hartmann, L., Marley, M., Cushing, M., Mainzer, A. K., Kirkpatrick, D., Jura, M., and Houck, J. R.
21. The Brewer-Dobson circulation in the light of high altitude in situ aircraft observations
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Tuck, A. F., Baumgardner, D., Chan, K. R., Dye, J. E., Elkins, J. W., Hovde, S. J., Kelly, K. K., Loewenstein, M., Margitan, J. J., May, R. D., Podolske, J. R., Proffitt, M. H., Karen Rosenlof, Smith, W. L., Webster, C. R., and Wilson, J. C.
22. Ice supersaturations exceeding 100% at the cold tropical tropopause: Implications for cirrus formation and dehydration
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Jensen, E. J., Smith, J. B., Pfister, L., Pittman, J. V., Weinstock, E. M., Sayres, D. S., Herman, R. L., Troy, R. F., Rosenlof, K., Thompson, T. L., Ann Fridlind, Hudson, P. K., Cziczo, D. J., Heymsfield, A. J., Schmitt, C., Wilson, J. C., NASA Ames Research Center (ARC), Harvard University [Cambridge], Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), University of California, NOAA Aeronomy Laboratory, National Oceanic and Atmospheric Administration (NOAA), Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado [Boulder]-National Oceanic and Atmospheric Administration (NOAA), National Center for Atmospheric Research [Boulder] (NCAR), and University of Denver
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[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere - Abstract
International audience; Recent in situ measurements at tropical tropopause temperatures as low as 187 K indicate supersaturations with respect to ice exceeding 100% with little or no ice present. In contrast, models used to simulate cloud formation near the tropopause assume a supersaturation threshold for ice nucleation of about 65% based on laboratory measurements of aqueous aerosol freezing. The high supersaturations reported here, along with cloud simulations assuming a plausible range of temperature histories in the sampled air mass, indicate that the vast majority of aerosols in the air sampled on this flight must have had supersaturation thresholds for ice nucleation exceeding 100% (i.e. near liquid water saturation at these temperatures). Possible explanations for this high threshold are that (1) the expressions used for calculating vapor pressure over supercooled water at low temperatures give values are at least 20% too low, (2) organic films on the aerosol surfaces reduce their accommodation coefficient for uptake of water, resulting in aerosols with more concentrated solutions when moderate-rapid cooling occurs and correspondingly inhibited homogeneous freezing, and (3) if surface freezing dominates, organic coatings may increase the surface energy of the ice embryo/vapor interface resulting in suppressed ice nucleation. Simulations of in situ cloud formation in the tropical tropopause layer (TTL) throughout the tropics indicate that if decreased accommodation coefficients and resulting high thresholds for ice nucleation prevailed throughout the tropics, then the calculated occurrence frequency and areal coverage of TTL cirrus would be significantly suppressed. However, the simulations also show that even if in situ TTL cirrus form only over a very small fraction of the tropics in the western Pacific, enough air passes through them due to rapid horizontal transport such that they can still effectively freeze-dry air entering the stratosphere. The TTL cirrus simulations show that even if very large supersaturations are required for ice nucleation, these large supersaturations should occur very rarely.
23. Structural characterisation of the oligosaccharide from Moraxella bovoculi type strain 237 (ATCC BAA-1259) lipooligosaccharide
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Jennifer C. Wilson, Wisam A. Dawood, I. Darren Grice, Antonio Molinaro, Immacolata Speciale, Ian R. Peak, Kosala S. Ravikumaran, Rebecca M. King, Cristina De Castro, Grice, I. D., Peak, I. R., Dawood, W. A., King, R. M., Ravikumaran, K. S., Speciale, I., Molinaro, A., de Castro, C., and Wilson, J. C.
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Lipopolysaccharides ,Pinkeye ,Moraxella bovoculi ,Heptose ,Oligosaccharides ,Lipopolysaccharide ,Biochemistry ,IBK ,Analytical Chemistry ,Microbiology ,NMR spectroscopy ,Endotoxin ,Lipooligosaccharide ,Carbohydrate Conformation ,Dairy cattle ,Moraxella ,Ocular disease ,chemistry.chemical_classification ,biology ,Strain (chemistry) ,LOS ,Organic Chemistry ,Moraxellaceae ,Infectious bovine keratoconjunctiviti ,General Medicine ,Oligosaccharide ,biology.organism_classification ,chemistry ,Infectious bovine keratoconjunctivitis ,Structural characterisation ,Bacteria - Abstract
The Gram-negative bacterium Moraxella bovoculi is associated with infectious bovine keratoconjunctivitis (IBK), colloquially known as 'pink-eye'. IBK is an extremely contagious ocular disease of cattle. We report here the structure of the oligosaccharide derived from the lipooligosaccharide from M. bovoculi type strain 237 (also known as ATCC BAA-1259T). GLC-MS and correlation NMR analysis of the oligosaccharide revealed 5 sugar residues, with a notable central branched 3,4,6-α-D-Glcp. An additional α-D-Manp was present ~30% on the sub-terminal α-D-Manp of the 4-linked branch. This oligosaccharide structure was consistent with other members of the Moraxellaceae where no heptose was present and 5-linked Kdo was directly attached to the central 3,4,6-α-D-Glcp.
- Published
- 2021
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