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Vance SD, Craft KL, Shock E, Schmidt BE, Lunine J, Hand KP, McKinnon WB, Spiers EM, Chivers C, Lawrence JD, Wolfenbarger N, Leonard EJ, Robinson KJ, Styczinski MJ, Persaud DM, Steinbrügge G, Zolotov MY, Quick LC, Scully JEC, Becker TM, Howell SM, Clark RN, Dombard AJ, Glein CR, Mousis O, Sephton MA, Castillo-Rogez J, Nimmo F, McEwen AS, Gudipati MS, Jun I, Jia X, Postberg F, Soderlund KM, Elder CM. Investigating Europa's Habitability with the Europa Clipper. Space Sci Rev 2023; 219:81. [PMID: 38046182 PMCID: PMC10687213 DOI: 10.1007/s11214-023-01025-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Accepted: 11/03/2023] [Indexed: 12/05/2023]
Abstract
The habitability of Europa is a property within a system, which is driven by a multitude of physical and chemical processes and is defined by many interdependent parameters, so that its full characterization requires collaborative investigation. To explore Europa as an integrated system to yield a complete picture of its habitability, the Europa Clipper mission has three primary science objectives: (1) characterize the ice shell and ocean including their heterogeneity, properties, and the nature of surface-ice-ocean exchange; (2) characterize Europa's composition including any non-ice materials on the surface and in the atmosphere, and any carbon-containing compounds; and (3) characterize Europa's geology including surface features and localities of high science interest. The mission will also address several cross-cutting science topics including the search for any current or recent activity in the form of thermal anomalies and plumes, performing geodetic and radiation measurements, and assessing high-resolution, co-located observations at select sites to provide reconnaissance for a potential future landed mission. Synthesizing the mission's science measurements, as well as incorporating remote observations by Earth-based observatories, the James Webb Space Telescope, and other space-based resources, to constrain Europa's habitability, is a complex task and is guided by the mission's Habitability Assessment Board (HAB).
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Affiliation(s)
- Steven D. Vance
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA
| | - Kathleen L. Craft
- Applied Physics Laboratory, Johns Hopkins University, Laurel, MD USA
| | - Everett Shock
- School of Earth & Space Exploration and School of Molecular Sciences, Arizona State University, Tempe, AZ USA
| | - Britney E. Schmidt
- Department of Astronomy and Department of Earth & Atmospheric Sciences, Cornell University, Ithaca, NY USA
| | - Jonathan Lunine
- Department of Astronomy and Department of Earth & Atmospheric Sciences, Cornell University, Ithaca, NY USA
| | - Kevin P. Hand
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA
| | - William B. McKinnon
- Department of Earth and Planetary Sciences and McDonnell Center for the Space Sciences, Washington University in St. Louis, Saint Louis, MO USA
| | - Elizabeth M. Spiers
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA USA
| | - Chase Chivers
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA USA
- Applied Ocean Physics and Engineering, Woods Hole Oceanographic Institution, Woods Hole, MA USA
| | - Justin D. Lawrence
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA USA
- Honeybee Robotics, Altadena, CA USA
| | - Natalie Wolfenbarger
- Institute for Geophysics, John A. and Katherine G. Jackson School of Geosciences, University of Texas at Austin, Austin, TX USA
| | - Erin J. Leonard
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA
| | | | | | - Divya M. Persaud
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA
| | - Gregor Steinbrügge
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA
| | - Mikhail Y. Zolotov
- School of Earth & Space Exploration and School of Molecular Sciences, Arizona State University, Tempe, AZ USA
| | | | | | | | - Samuel M. Howell
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA
| | | | - Andrew J. Dombard
- Dept. of Earth and Environmental Sciences, University of Illinois Chicago, Chicago, USA
| | | | - Olivier Mousis
- Aix Marseille Université, CNRS, LAM (Laboratoire d’Astrophysique de Marseille), Marseille, France
| | - Mark A. Sephton
- Impacts and Astromaterials Research Centre, Department of Earth Science and Engineering, Imperial College London, London, United Kingdom
| | | | - Francis Nimmo
- Department of Earth and Planetary Sciences, University of California, Santa Cruz, CA USA
| | - Alfred S. McEwen
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ USA
| | - Murthy S. Gudipati
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA
| | - Insoo Jun
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA
| | - Xianzhe Jia
- Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI USA
| | - Frank Postberg
- Institut für Geologische Wissenschaften, Freie Universität Berlin, Berlin, Germany
| | - Krista M. Soderlund
- Institute for Geophysics, John A. and Katherine G. Jackson School of Geosciences, University of Texas at Austin, Austin, TX USA
| | - Catherine M. Elder
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA
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McLean JH, Clark RN. Seven new genera and thirty-four new species of buccinoid gastropods (Neogastropoda: Buccinidae) from the Aleutian Islands, Alaska. Zootaxa 2023; 5351:151-201. [PMID: 38221493 DOI: 10.11646/zootaxa.5351.2.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Indexed: 01/16/2024]
Abstract
Seven new genera and thirty-four new species of gastropods in the in the family Buccinidae, are described from the Aleutian Islands. The new taxa represent five subfamilies: Parancistrolepidinae Habe, 1972: Boreancistrolepis excelsus n. gen. & n. sp. Beringiinae Golikov & Starabogatov, 1975: Aleutijapelion mirandus n. gen. & n. sp.; Beringius nearensis n. sp., B. amliensis n. sp., B. bisulcatus n. sp., B. kiskensis n. sp., B. stanchfieldi n. sp., B. frausseni n. sp., B. aurulentus n. sp., B. maristempestus n. sp., B. undataformis n. sp.; Exiloberingius exiguus n. gen. & n. sp. Neptuneinae Stimpson, 1865: Aulacofusus canaliculatus n. sp., A. tanagaensis n. sp.; Neptunea aleutica n. sp., N. baxteri n. sp., N. dominator n. sp., N. petrelensis n. sp., N. quhmax n. sp., N. vesteraalen n. sp.; N. harrisoni n. sp., N. jewetti n. sp., Laevisipho galaxaios n. gen & n. sp., L. kessleri n. sp.; Volutopsiinae: Volutopsius nanus n. sp., Volutopsius gracilis n. sp.; Crebrivolutopsius labidentatus n. gen. & n. sp. Buccininae Rafinesque, 1815: Aleutibuccinum n. gen.; Castaneobuccinum orri n. gen. & n. sp., C. lauthi, n. sp., C. clinopsis n. sp., C. pagodaformis n. sp.; Sulcosinus carinatus n. sp.; Buccinum lanatum n. sp.; and Buccinum katharinae n. gen. & n. sp. The new genera and species are distinguished by the morphological characters of the shells and radulae.
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Affiliation(s)
- James H McLean
- Natural History Museum of Los Angeles County; 900 Exposition Boulevard; Los Angeles; California 90007 USA.
| | - Roger N Clark
- Natural History Museum of Los Angeles County; 900 Exposition Boulevard; Los Angeles; California 90007 USA; Santa Barbara Museum of Natural History; 2559 Puesta del Sol Road; Santa Barbara; California 93105 USA.
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Tiscareno MS, Nicholson PD, Cuzzi JN, Spilker LJ, Murray CD, Hedman MM, Colwell JE, Burns JA, Brooks SM, Clark RN, Cooper NJ, Deau E, Ferrari C, Filacchione G, Jerousek RG, Le Mouélic S, Morishima R, Pilorz S, Rodriguez S, Showalter MR, Badman SV, Baker EJ, Buratti BJ, Baines KH, Sotin C. Close-range remote sensing of Saturn's rings during Cassini's ring-grazing orbits and Grand Finale. Science 2019; 364:364/6445/eaau1017. [PMID: 31196983 DOI: 10.1126/science.aau1017] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 05/07/2019] [Indexed: 11/02/2022]
Abstract
Saturn's rings are an accessible exemplar of an astrophysical disk, tracing the Saturn system's dynamical processes and history. We present close-range remote-sensing observations of the main rings from the Cassini spacecraft. We find detailed sculpting of the rings by embedded masses, and banded texture belts throughout the rings. Saturn-orbiting streams of material impact the F ring. There are fine-scaled correlations among optical depth, spectral properties, and temperature in the B ring, but anticorrelations within strong density waves in the A ring. There is no spectral distinction between plateaux and the rest of the C ring, whereas the region outward of the Keeler gap is spectrally distinct from nearby regions. These results likely indicate that radial stratification of particle physical properties, rather than compositional differences, is responsible for producing these ring structures.
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Affiliation(s)
- Matthew S Tiscareno
- Carl Sagan Center for the Study of Life in the Universe, SETI Institute, Mountain View, CA 94043, USA.
| | | | | | - Linda J Spilker
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | - Carl D Murray
- Astronomy Unit, Queen Mary University of London, London E1 4NS, UK
| | - Matthew M Hedman
- Department of Physics, University of Idaho, Moscow, ID 83844, USA
| | - Joshua E Colwell
- Department of Physics, University of Central Florida, Orlando, FL 32816, USA
| | - Joseph A Burns
- Department of Astronomy, Cornell University, Ithaca, NY 14853, USA.,College of Engineering, Cornell University, Ithaca, NY 14853, USA
| | - Shawn M Brooks
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | | | | | - Estelle Deau
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA.,Department of Earth, Planetary, and Space Sciences, University of California at Los Angeles, Los Angeles, CA 90095, USA
| | - Cecile Ferrari
- Institut de Physique du Globe de Paris, Centre National de la Recherche Scientifique (CNRS)-Unité Mixte de Recherche (UMR) 7154, Université Paris-Diderot, Université Sorbonne-Paris-Cité (USPC), Paris, France
| | - Gianrico Filacchione
- INAF-IAPS (Istituto Nazionale di AstroFisica-Istituto di Astrofisica e Planetologia Spaziali), Rome, Italy
| | - Richard G Jerousek
- Department of Physics, University of Central Florida, Orlando, FL 32816, USA
| | - Stéphane Le Mouélic
- Laboratoire de Planetologie et Geodynamique, CNRS-UMR 6112, Université de Nantes, 44322 Nantes, France
| | - Ryuji Morishima
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA.,Department of Earth, Planetary, and Space Sciences, University of California at Los Angeles, Los Angeles, CA 90095, USA
| | - Stu Pilorz
- Carl Sagan Center for the Study of Life in the Universe, SETI Institute, Mountain View, CA 94043, USA
| | - Sébastien Rodriguez
- Institut de Physique du Globe de Paris, Centre National de la Recherche Scientifique (CNRS)-Unité Mixte de Recherche (UMR) 7154, Université Paris-Diderot, Université Sorbonne-Paris-Cité (USPC), Paris, France
| | - Mark R Showalter
- Carl Sagan Center for the Study of Life in the Universe, SETI Institute, Mountain View, CA 94043, USA
| | - Sarah V Badman
- Physics Department, Lancaster University, Lancaster LA1 4YB, UK
| | | | - Bonnie J Buratti
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | - Kevin H Baines
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | - Christophe Sotin
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
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Thompson DR, Candela A, Wettergreen DS, Dobrea EN, Swayze GA, Clark RN, Greenberger R. Spatial Spectroscopic Models for Remote Exploration. Astrobiology 2018; 18:934-954. [PMID: 30035643 DOI: 10.1089/ast.2017.1782] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Ancient hydrothermal systems are a high-priority target for a future Mars sample return mission because they contain energy sources for microbes and can preserve organic materials (Farmer, 2000 ; MEPAG Next Decade Science Analysis Group, 2008 ; McLennan et al., 2012 ; Michalski et al., 2017 ). Characterizing these large, heterogeneous systems with a remote explorer is difficult due to communications bandwidth and latency; such a mission will require significant advances in spacecraft autonomy. Science autonomy uses intelligent sensor platforms that analyze data in real-time, setting measurement and downlink priorities to provide the best information toward investigation goals. Such automation must relate abstract science hypotheses to the measurable quantities available to the robot. This study captures these relationships by formalizing traditional "science traceability matrices" into probabilistic models. This permits experimental design techniques to optimize future measurements and maximize information value toward the investigation objectives, directing remote explorers that respond appropriately to new data. Such models are a rich new language for commanding informed robotic decision making in physically grounded terms. We apply these models to quantify the information content of different rover traverses providing profiling spectroscopy of Cuprite Hills, Nevada. We also develop two methods of representing spatial correlations using human-defined maps and remote sensing data. Model unit classifications are broadly consistent with prior maps of the site's alteration mineralogy, indicating that the model has successfully represented critical spatial and mineralogical relationships at Cuprite. Key Words: Autonomous science-Imaging spectroscopy-Alteration mineralogy-Field geology-Cuprite-AVIRIS-NG-Robotic exploration. Astrobiology 18, 934-954.
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Affiliation(s)
- David R Thompson
- 1 Jet Propulsion Laboratory, California Institute of Technology , Pasadena, California
| | - Alberto Candela
- 2 The Robotics Institute, Carnegie Mellon University , Pittsburgh, Pennsylvania
| | - David S Wettergreen
- 2 The Robotics Institute, Carnegie Mellon University , Pittsburgh, Pennsylvania
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Abstract
A new species of asteriid sea star of the genus Leptasterias (Order Forcipulatida) is described from the nearshore waters of the Aleutian Islands. Leptaterias tatei sp. nov. is distinguished from Leptasterias stolacantha Fisher, 1930, by the characteristics of the spines and pedicellariae. Geographic distribution is discussed and a key to the five-rayed Leptasterias of the Aleutian Islands is provided.
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Affiliation(s)
- Roger N Clark
- Associate in Invertebrate Zoology, Los Angeles County Museum of Natural History, 900 Exposition Boulevard, Los Angeles, California 90007 USA Mailing address: 3808 E. Pinehurst Dr., Eagle Mountain, Utah 84005-6007 USA.;
| | - Stephen C Jewett
- Research Professor, Institute of Marine Science, 128 O'Neill, P.O. Box 757220, University of Alaska Fairbanks, Fairbanks, Alaska 99775-7220 USA.;
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Barnes JW, Buratti BJ, Turtle EP, Bow J, Dalba PA, Perry J, Brown RH, Rodriguez S, Mouélic SL, Baines KH, Sotin C, Lorenz RD, Malaska MJ, McCord TB, Clark RN, Jaumann R, Hayne PO, Nicholson PD, Soderblom JM, Soderblom LA. Precipitation-induced surface brightenings seen on Titan by Cassini VIMS and ISS. ACTA ACUST UNITED AC 2013. [DOI: 10.1186/2191-2521-2-1] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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King TVV, Clark RN. Spectral characteristics of chlorites and Mg-serpentines using high-resolution reflectance spectroscopy. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jb094ib10p13997] [Citation(s) in RCA: 115] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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McCord TB, Clark RN, Hawke BR, McFadden LA, Owensby PD, Pieters CM, Adams JB. Moon: Near-infrared spectral reflectance, A first good look. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jb086ib11p10883] [Citation(s) in RCA: 144] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Clark RN. Spectral properties of mixtures of montmorillonite and dark carbon grains: Implications for remote sensing minerals containing chemically and physically adsorbed water. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jb088ib12p10635] [Citation(s) in RCA: 138] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Clark RN, McCord TB. Mars residual north polar cap: Earth-based spectroscopic confirmation of water ice as a major constituent and evidence for hydrated minerals. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jb087ib01p00367] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Clark RN, Lucey PG. Spectral properties of ice-particulate mixtures and implications for remote sensing: 1. Intimate mixtures. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jb089ib07p06341] [Citation(s) in RCA: 147] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Cornet T, Bourgeois O, Le Mouélic S, Rodriguez S, Sotin C, Barnes JW, Brown RH, Baines KH, Buratti BJ, Clark RN, Nicholson PD. Edge detection applied to Cassini images reveals no measurable displacement of Ontario Lacus' margin between 2005 and 2010. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2012je004073] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Clark RN, Curchin JM, Barnes JW, Jaumann R, Soderblom L, Cruikshank DP, Brown RH, Rodriguez S, Lunine J, Stephan K, Hoefen TM, Le Mouélic S, Sotin C, Baines KH, Buratti BJ, Nicholson PD. Detection and mapping of hydrocarbon deposits on Titan. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009je003369] [Citation(s) in RCA: 134] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Abstract
This study evaluates the effectiveness of an incentive procedure designed to induce litter collection in a large forest campground. Children in the campground were offered their choice of a variety of reinforcers for picking up and properly disposing of litter. The procedure resulted in a sharp decline in four types of litter planted in the campground.
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Abstract
This study evaluates the differential effectiveness of six different anti-litter procedures in two neighborhood theaters. The procedures used to encourage individuals in attendance to pick up litter and deposit it properly included: providing litterbags, providing litterbags with instructions to use them, providing extra trash cans, showing a special anti-litter film before the feature film, and providing incentives for the appropriate deposit of litter. In both theaters, the incentive procedures resulted in the removal of over 90% of all litter by the children in attendance, a figure far above that achieved by the other procedures investigated.
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Abstract
The objectives were to quantify and size ambient aerosolized dust in and around the facilities of 4 southern High Plains dairies of New Mexico and to determine where health of workers might be vulnerable to particulate aerosols, based on aerosol concentrations that exceed national air quality standards. Ambient dust air samples were collected upwind (background) and downwind of 3 dairy location sites (loafing pen boundary, commodity, and compost field). The indoor milking parlor, a fourth site, was monitored immediately upwind and downwind. Aerosolized particulate samples were collected using high-volume sequential reference air samplers, laser aerosol monitors, and cyclone air samplers. The overall (main effects and estimable interactions) statistical general linear model statement for particulate matter (PM(10); particulate matter with an aerodynamic diameter of up to 10 microm) and PM(2.5) resulted in a greater mean concentration of dust in the winter (PM(10) = 97.4 +/- 4.4 microg/m(3); PM(2.5) = 32.6 +/- 2.6 microg/m(3)) compared with the summer (PM(10) = 71.9 +/- 5.0 microg/m(3); PM(2.5) = 18.1 +/- 1.2 microg/m(3)). The upwind and downwind boundary PM(10) concentrations were significantly higher in the winter (upwind = 64.3 +/- 9.5 microg/m(3); downwind = 119.8 +/- 13.0 microg/m(3)) compared with the summer (upwind = 35.2 +/- 7.5 microg/m(3); downwind = 66.8 +/- 11.8 microg/m(3)). The milking parlor PM(10) and PM(2.5) concentration data were significantly higher in the winter (PM(10) = 119.5 +/- 5.8 microg/m(3); PM(2.5) = 55.3 +/- 5.8microg/m(3)) compared with the summer (PM(10) = 88.6.0 +/- 5.8 microg/m(3); PM(2.5) = 21.0 +/- 2.1 microg/m(3)). Personnel should be protected from high aerosol concentrations found at the commodity barn, compost field, and milking parlor during the winter.
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Affiliation(s)
- C W Purdy
- USDA, Agricultural Research Service, Conservation and Production Research Laboratory, PO Drawer 10, Bushland, TX 79012, USA
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Ehlmann BL, Mustard JF, Swayze GA, Clark RN, Bishop JL, Poulet F, Des Marais DJ, Roach LH, Milliken RE, Wray JJ, Barnouin-Jha O, Murchie SL. Identification of hydrated silicate minerals on Mars using MRO-CRISM: Geologic context near Nili Fossae and implications for aqueous alteration. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2009je003339] [Citation(s) in RCA: 383] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Abstract
Data from the Visual and Infrared Mapping Spectrometer (VIMS) on Cassini during its flyby of the Moon in 1999 show a broad absorption at 3 micrometers due to adsorbed water and near 2.8 micrometers attributed to hydroxyl in the sunlit surface on the Moon. The amounts of water indicated in the spectra depend on the type of mixing and the grain sizes in the rocks and soils but could be 10 to 1000 parts per million and locally higher. Water in the polar regions may be water that has migrated to the colder environments there. Trace hydroxyl is observed in the anorthositic highlands at lower latitudes.
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Affiliation(s)
- Roger N Clark
- U.S. Geological Survey, Mail Stop 964, Box 25046 Federal Center, Denver, CO 80227, USA.
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Murchie SL, Mustard JF, Ehlmann BL, Milliken RE, Bishop JL, McKeown NK, Noe Dobrea EZ, Seelos FP, Buczkowski DL, Wiseman SM, Arvidson RE, Wray JJ, Swayze G, Clark RN, Des Marais DJ, McEwen AS, Bibring JP. A synthesis of Martian aqueous mineralogy after 1 Mars year of observations from the Mars Reconnaissance Orbiter. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2009je003342] [Citation(s) in RCA: 356] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Ehlmann BL, Mustard JF, Murchie SL, Poulet F, Bishop JL, Brown AJ, Calvin WM, Clark RN, Marais DJD, Milliken RE, Roach LH, Roush TL, Swayze GA, Wray JJ. Orbital identification of carbonate-bearing rocks on Mars. Science 2009; 322:1828-32. [PMID: 19095939 DOI: 10.1126/science.1164759] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Geochemical models for Mars predict carbonate formation during aqueous alteration. Carbonate-bearing rocks had not previously been detected on Mars' surface, but Mars Reconnaissance Orbiter mapping reveals a regional rock layer with near-infrared spectral characteristics that are consistent with the presence of magnesium carbonate in the Nili Fossae region. The carbonate is closely associated with both phyllosilicate-bearing and olivine-rich rock units and probably formed during the Noachian or early Hesperian era from the alteration of olivine by either hydrothermal fluids or near-surface water. The presence of carbonate as well as accompanying clays suggests that waters were neutral to alkaline at the time of its formation and that acidic weathering, proposed to be characteristic of Hesperian Mars, did not destroy these carbonates and thus did not dominate all aqueous environments.
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Affiliation(s)
- Bethany L. Ehlmann
- Department of Geological Sciences, Brown University, Providence, RI02912, USA
- Johns Hopkins University/Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723, USA
- Institut d'Astrophysique Spatiale, Université Paris Sud 11, 91405 Orsay, France
- SETI Institute and NASA Ames Research Center, 515 North Whisman Road, Mountain View, CA 94043, USA
- Department of Geological Sciences and Engineering, University of Nevada, MS 172, 1664 North Virginia Street, Reno, NV 89557, USA
| | - John F. Mustard
- Department of Geological Sciences, Brown University, Providence, RI02912, USA
- Johns Hopkins University/Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723, USA
- Institut d'Astrophysique Spatiale, Université Paris Sud 11, 91405 Orsay, France
- SETI Institute and NASA Ames Research Center, 515 North Whisman Road, Mountain View, CA 94043, USA
- Department of Geological Sciences and Engineering, University of Nevada, MS 172, 1664 North Virginia Street, Reno, NV 89557, USA
| | - Scott L. Murchie
- Department of Geological Sciences, Brown University, Providence, RI02912, USA
- Johns Hopkins University/Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723, USA
- Institut d'Astrophysique Spatiale, Université Paris Sud 11, 91405 Orsay, France
- SETI Institute and NASA Ames Research Center, 515 North Whisman Road, Mountain View, CA 94043, USA
- Department of Geological Sciences and Engineering, University of Nevada, MS 172, 1664 North Virginia Street, Reno, NV 89557, USA
| | - Francois Poulet
- Department of Geological Sciences, Brown University, Providence, RI02912, USA
- Johns Hopkins University/Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723, USA
- Institut d'Astrophysique Spatiale, Université Paris Sud 11, 91405 Orsay, France
- SETI Institute and NASA Ames Research Center, 515 North Whisman Road, Mountain View, CA 94043, USA
- Department of Geological Sciences and Engineering, University of Nevada, MS 172, 1664 North Virginia Street, Reno, NV 89557, USA
| | - Janice L. Bishop
- Department of Geological Sciences, Brown University, Providence, RI02912, USA
- Johns Hopkins University/Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723, USA
- Institut d'Astrophysique Spatiale, Université Paris Sud 11, 91405 Orsay, France
- SETI Institute and NASA Ames Research Center, 515 North Whisman Road, Mountain View, CA 94043, USA
- Department of Geological Sciences and Engineering, University of Nevada, MS 172, 1664 North Virginia Street, Reno, NV 89557, USA
| | - Adrian J. Brown
- Department of Geological Sciences, Brown University, Providence, RI02912, USA
- Johns Hopkins University/Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723, USA
- Institut d'Astrophysique Spatiale, Université Paris Sud 11, 91405 Orsay, France
- SETI Institute and NASA Ames Research Center, 515 North Whisman Road, Mountain View, CA 94043, USA
- Department of Geological Sciences and Engineering, University of Nevada, MS 172, 1664 North Virginia Street, Reno, NV 89557, USA
| | - Wendy M. Calvin
- Department of Geological Sciences, Brown University, Providence, RI02912, USA
- Johns Hopkins University/Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723, USA
- Institut d'Astrophysique Spatiale, Université Paris Sud 11, 91405 Orsay, France
- SETI Institute and NASA Ames Research Center, 515 North Whisman Road, Mountain View, CA 94043, USA
- Department of Geological Sciences and Engineering, University of Nevada, MS 172, 1664 North Virginia Street, Reno, NV 89557, USA
| | - Roger N. Clark
- Department of Geological Sciences, Brown University, Providence, RI02912, USA
- Johns Hopkins University/Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723, USA
- Institut d'Astrophysique Spatiale, Université Paris Sud 11, 91405 Orsay, France
- SETI Institute and NASA Ames Research Center, 515 North Whisman Road, Mountain View, CA 94043, USA
- Department of Geological Sciences and Engineering, University of Nevada, MS 172, 1664 North Virginia Street, Reno, NV 89557, USA
| | - David J. Des Marais
- Department of Geological Sciences, Brown University, Providence, RI02912, USA
- Johns Hopkins University/Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723, USA
- Institut d'Astrophysique Spatiale, Université Paris Sud 11, 91405 Orsay, France
- SETI Institute and NASA Ames Research Center, 515 North Whisman Road, Mountain View, CA 94043, USA
- Department of Geological Sciences and Engineering, University of Nevada, MS 172, 1664 North Virginia Street, Reno, NV 89557, USA
| | - Ralph E. Milliken
- Department of Geological Sciences, Brown University, Providence, RI02912, USA
- Johns Hopkins University/Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723, USA
- Institut d'Astrophysique Spatiale, Université Paris Sud 11, 91405 Orsay, France
- SETI Institute and NASA Ames Research Center, 515 North Whisman Road, Mountain View, CA 94043, USA
- Department of Geological Sciences and Engineering, University of Nevada, MS 172, 1664 North Virginia Street, Reno, NV 89557, USA
| | - Leah H. Roach
- Department of Geological Sciences, Brown University, Providence, RI02912, USA
- Johns Hopkins University/Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723, USA
- Institut d'Astrophysique Spatiale, Université Paris Sud 11, 91405 Orsay, France
- SETI Institute and NASA Ames Research Center, 515 North Whisman Road, Mountain View, CA 94043, USA
- Department of Geological Sciences and Engineering, University of Nevada, MS 172, 1664 North Virginia Street, Reno, NV 89557, USA
| | - Ted L. Roush
- Department of Geological Sciences, Brown University, Providence, RI02912, USA
- Johns Hopkins University/Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723, USA
- Institut d'Astrophysique Spatiale, Université Paris Sud 11, 91405 Orsay, France
- SETI Institute and NASA Ames Research Center, 515 North Whisman Road, Mountain View, CA 94043, USA
- Department of Geological Sciences and Engineering, University of Nevada, MS 172, 1664 North Virginia Street, Reno, NV 89557, USA
| | - Gregg A. Swayze
- Department of Geological Sciences, Brown University, Providence, RI02912, USA
- Johns Hopkins University/Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723, USA
- Institut d'Astrophysique Spatiale, Université Paris Sud 11, 91405 Orsay, France
- SETI Institute and NASA Ames Research Center, 515 North Whisman Road, Mountain View, CA 94043, USA
- Department of Geological Sciences and Engineering, University of Nevada, MS 172, 1664 North Virginia Street, Reno, NV 89557, USA
| | - James J. Wray
- Department of Geological Sciences, Brown University, Providence, RI02912, USA
- Johns Hopkins University/Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723, USA
- Institut d'Astrophysique Spatiale, Université Paris Sud 11, 91405 Orsay, France
- SETI Institute and NASA Ames Research Center, 515 North Whisman Road, Mountain View, CA 94043, USA
- Department of Geological Sciences and Engineering, University of Nevada, MS 172, 1664 North Virginia Street, Reno, NV 89557, USA
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Clark RN, Housley SL, Ahktar MN, Barnetson R. Metastatic Oesophageal Adenocarcinoma to the Urinary Bladder. Scott Med J 2008. [DOI: 10.1258/rsmsmj.53.4.10e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- RN Clark
- Departments of Urology and Pathology, Southern General Hospital, Govan Road, Glasgow
| | - SL Housley
- Departments of Urology and Pathology, Southern General Hospital, Govan Road, Glasgow
| | - MN Ahktar
- Departments of Urology and Pathology, Southern General Hospital, Govan Road, Glasgow
| | - R Barnetson
- Departments of Urology and Pathology, Southern General Hospital, Govan Road, Glasgow
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27
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Le Mouélic S, Paillou P, Janssen MA, Barnes JW, Rodriguez S, Sotin C, Brown RH, Baines KH, Buratti BJ, Clark RN, Crapeau M, Encrenaz PJ, Jaumann R, Geudtner D, Paganelli F, Soderblom L, Tobie G, Wall S. Mapping and interpretation of Sinlap crater on Titan using Cassini VIMS and RADAR data. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2007je002965] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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28
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Cole NA, Clark RN, Todd RW, Richardson CR, Gueye A, Greene LW, McBride K. Influence of dietary crude protein concentration and source on potential ammonia emissions from beef cattle manure. J Anim Sci 2007; 83:722-31. [PMID: 15705770 DOI: 10.2527/2005.833722x] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Emissions of ammonia, as well as other gases and particulates, to the atmosphere are a growing concern of livestock producers, the general public, and regulators. The concentration and ruminal degradability of CP in beef cattle diets may affect urinary and fecal excretion of N and thus may affect ammonia emissions from beef cattle feed yards. To determine the effects of dietary CP concentration and degradability on potential ammonia emissions, 54 steers were randomly assigned to nine dietary treatments in a 3 x 3 factorial arrangement of treatments. Treatments consisted of three dietary CP concentrations (11.5, 13, and 14.5%) and three supplemental urea:cottonseed meal ratios (100:0, 50:50, and 0:100 of supplemental N). Steers were confined to tie stalls, and feces and urine excreted were collected and frozen after approximately 30, 75, and 120 d on feed. One percent of daily urine and feces excretion were added to polyethylene chambers containing 1,550 g of soil. Chambers were sealed, and ammonia emissions were trapped in an acid solution for 7 d using a vacuum system. As the protein concentration in the diet increased from 11.5 to 13%, in vitro daily ammonia emissions increased (P < 0.01) 60 to 200%, due primarily to increased urinary N excretion. As days on feed increased, in vitro ammonia emissions also increased (P < 0.01). Potential ammonia losses were highly correlated (P < 0.01) to urinary N (r2 = 0.69), urinary urea-N (r2 = 0.58) excretion, serum urea-N concentration (r2 = 0.52), and intake of degradable protein N (r2 = 0.23). Although dietary composition can affect daily ammonia losses, daily ammonia emissions must be balanced with effects on animal performance to determine optimal protein concentrations and forms in the diet.
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Affiliation(s)
- N A Cole
- ARS, USDA, Conservation and Production Research Laboratory, Bushland, TX 79012, USA.
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29
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Cruikshank DP, Dalton JB, Dalle Ore CM, Bauer J, Stephan K, Filacchione G, Hendrix AR, Hansen CJ, Coradini A, Cerroni P, Tosi F, Capaccioni F, Jaumann R, Buratti BJ, Clark RN, Brown RH, Nelson RM, McCord TB, Baines KH, Nicholson PD, Sotin C, Meyer AW, Bellucci G, Combes M, Bibring JP, Langevin Y, Sicardy B, Matson DL, Formisano V, Drossart P, Mennella V. Surface composition of Hyperion. Nature 2007; 448:54-6. [PMID: 17611536 DOI: 10.1038/nature05948] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2007] [Accepted: 05/16/2007] [Indexed: 11/09/2022]
Abstract
Hyperion, Saturn's eighth largest icy satellite, is a body of irregular shape in a state of chaotic rotation. The surface is segregated into two distinct units. A spatially dominant high-albedo unit having the strong signature of H2O ice contrasts with a unit that is about a factor of four lower in albedo and is found mostly in the bottoms of cup-like craters. Here we report observations of Hyperion's surface in the ultraviolet and near-infrared spectral regions with two optical remote sensing instruments on the Cassini spacecraft at closest approach during a fly-by on 25-26 September 2005. The close fly-by afforded us the opportunity to obtain separate reflectance spectra of the high- and low-albedo surface components. The low-albedo material has spectral similarities and compositional signatures that link it with the surface of Phoebe and a hemisphere-wide superficial coating on Iapetus.
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Affiliation(s)
- D P Cruikshank
- NASA Ames Research Center, MS 245-6, NASA Ames Research Center, MS 211-3, Moffett Field, California 94035, USA.
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30
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Brown RH, Clark RN, Buratti BJ, Cruikshank DP, Barnes JW, Mastrapa RME, Bauer J, Newman S, Momary T, Baines KH, Bellucci G, Capaccioni F, Cerroni P, Combes M, Coradini A, Drossart P, Formisano V, Jaumann R, Langevin Y, Matson DL, McCord TB, Nelson RM, Nicholson PD, Sicardy B, Sotin C. Composition and Physical Properties of Enceladus' Surface. Science 2006; 311:1425-8. [PMID: 16527972 DOI: 10.1126/science.1121031] [Citation(s) in RCA: 170] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Observations of Saturn's satellite Enceladus using Cassini's Visual and Infrared Mapping Spectrometer instrument were obtained during three flybys of Enceladus in 2005. Enceladus' surface is composed mostly of nearly pure water ice except near its south pole, where there are light organics, CO2, and amorphous and crystalline water ice, particularly in the region dubbed the "tiger stripes." An upper limit of 5 precipitable nanometers is derived for CO in the atmospheric column above Enceladus, and 2% for NH3 in global surface deposits. Upper limits of 140 kelvin (for a filled pixel) are derived for the temperatures in the tiger stripes.
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Affiliation(s)
- Robert H Brown
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, USA
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31
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Sotin C, Jaumann R, Buratti BJ, Brown RH, Clark RN, Soderblom LA, Baines KH, Bellucci G, Bibring JP, Capaccioni F, Cerroni P, Combes M, Coradini A, Cruikshank DP, Drossart P, Formisano V, Langevin Y, Matson DL, McCord TB, Nelson RM, Nicholson PD, Sicardy B, LeMouelic S, Rodriguez S, Stephan K, Scholz CK. Release of volatiles from a possible cryovolcano from near-infrared imaging of Titan. Nature 2005; 435:786-9. [PMID: 15944697 DOI: 10.1038/nature03596] [Citation(s) in RCA: 174] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2004] [Accepted: 03/24/2005] [Indexed: 11/09/2022]
Abstract
Titan is the only satellite in our Solar System with a dense atmosphere. The surface pressure is 1.5 bar (ref. 1) and, similar to the Earth, N2 is the main component of the atmosphere. Methane is the second most important component, but it is photodissociated on a timescale of 10(7) years (ref. 3). This short timescale has led to the suggestion that Titan may possess a surface or subsurface reservoir of hydrocarbons to replenish the atmosphere. Here we report near-infrared images of Titan obtained on 26 October 2004 by the Cassini spacecraft. The images show that a widespread methane ocean does not exist; subtle albedo variations instead suggest topographical variations, as would be expected for a more solid (perhaps icy) surface. We also find a circular structure approximately 30 km in diameter that does not resemble any features seen on other icy satellites. We propose that the structure is a dome formed by upwelling icy plumes that release methane into Titan's atmosphere.
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Affiliation(s)
- C Sotin
- Laboratoire de Planétologie et Géodynamique, UMR CNRS 6112, Université de Nantes, Nantes, 44100, France.
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32
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Clark RN, Brown RH, Jaumann R, Cruikshank DP, Nelson RM, Buratti BJ, McCord TB, Lunine J, Baines KH, Bellucci G, Bibring JP, Capaccioni F, Cerroni P, Coradini A, Formisano V, Langevin Y, Matson DL, Mennella V, Nicholson PD, Sicardy B, Sotin C, Hoefen TM, Curchin JM, Hansen G, Hibbits K, Matz KD. Compositional maps of Saturn's moon Phoebe from imaging spectroscopy. Nature 2005; 435:66-9. [PMID: 15875014 DOI: 10.1038/nature03558] [Citation(s) in RCA: 127] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2004] [Accepted: 03/11/2005] [Indexed: 11/08/2022]
Abstract
The origin of Phoebe, which is the outermost large satellite of Saturn, is of particular interest because its inclined, retrograde orbit suggests that it was gravitationally captured by Saturn, having accreted outside the region of the solar nebula in which Saturn formed. By contrast, Saturn's regular satellites (with prograde, low-inclination, circular orbits) probably accreted within the sub-nebula in which Saturn itself formed. Here we report imaging spectroscopy of Phoebe resulting from the Cassini-Huygens spacecraft encounter on 11 June 2004. We mapped ferrous-iron-bearing minerals, bound water, trapped CO2, probable phyllosilicates, organics, nitriles and cyanide compounds. Detection of these compounds on Phoebe makes it one of the most compositionally diverse objects yet observed in our Solar System. It is likely that Phoebe's surface contains primitive materials from the outer Solar System, indicating a surface of cometary origin.
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Affiliation(s)
- Roger N Clark
- US Geological Survey, MS964, Box 25046, Federal Center, Denver, Colorado 80225, USA.
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Clark RN, Swayze GA, Livo KE, Kokaly RF, Sutley SJ, Dalton JB, McDougal RR, Gent CA. Imaging spectroscopy: Earth and planetary remote sensing with the USGS Tetracorder and expert systems. ACTA ACUST UNITED AC 2003. [DOI: 10.1029/2002je001847] [Citation(s) in RCA: 446] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Abstract
We have detected a 30,000-square-kilometer area rich in olivine in the Nili Fossae region of Mars. Nili Fossae has been interpreted as a complex of grabens and fractures related to the formation of the Isidis impact basin. We propose that post-impact faulting of this area has exposed subsurface layers rich in olivine. Linear mixture analysis of Thermal Emission Spectrometer spectra shows surface exposures of 30% olivine, where the composition of the olivine ranges from Fo30 to Fo70.
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35
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Ruff SW, Christensen PR, Clark RN, Kieffer HH, Malin MC, Bandfield JL, Jakosky BM, Lane MD, Mellon MT, Presley MA. Mars' “White Rock” feature lacks evidence of an aqueous origin: Results from Mars Global Surveyor. ACTA ACUST UNITED AC 2001. [DOI: 10.1029/2000je001329] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Abstract
OBJECTIVE To determine the impact of feedyards on endotoxin concentration, fecal coliform count, and other water quality measurements during winter and summer in feedyard playas (shallow lakes). SAMPLE POPULATION Water samples obtained from 7 feedyard playas and 3 nonfeedyard control playas. PROCEDURE Surface water samples were collected from each playa and at various depths from 3 feedyard playas. Endotoxin concentrations, 22 water quality variables, and fecal coliform counts were determined in samples collected in summer and winter from various combinations of playas. RESULTS Cattle numbers per feedyard ranged from 40,000 to 175,000 head/y. Mean endotoxin concentrations were significantly lower in control playas than in feedyard playas in winter and summer. Endotoxin concentration appeared to be homogenous at various water depths. Values for 20 of 22 water quality variables were higher in the feedyard playas than in control playas in winter and summer. In winter only, mean total fecal coliform concentration in feedyard playas was significantly greater than in control playas. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that feedyards have the potential to impact water quality in playas, and cattle should not be allowed access to them. Feedyard playa water should not be used under high pressure to settle dust in pens with cattle or to cool cattle, because aerosols containing pathogens and high concentrations of endotoxin are a health hazard for humans and cattle?
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Affiliation(s)
- C W Purdy
- Animal Waste Resources, Agricultural Research Service, United States Department of Agriculture, Bushland, TX 79012, USA
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37
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Abstract
Endotoxin (LPS) is a potent inducer of tumor necrosis factor-α (TNF-α) and manganese superoxide dismutase (MnSOD). Recent evidence suggests that LPS induction of TNF-α and MnSOD mRNAs is mediated through distinct intracellular signal transduction pathways. Membrane CD14 (mCD14) and Toll-like receptor-4 (TLR4) mediate LPS induction of TNF-α in macrophages. In the current study, we evaluated the role of mCD14 and TLR4 in LPS induction of MnSOD using peritoneal macrophages from CD14 knockout (CD14-KO) mice and mice with the Tlr4 gene point mutation (C3H/HeJ) or deletion (C57BL/10ScCr). We studied mCD14-dependent (1 and 10 ng/ml) and mCD14-independent (1,000 ng/ml) concentrations of LPS. Compared with control (BALB/c) macrophages, LPS at 1 and 10 ng/ml failed to induce TNF-α or MnSOD mRNA in CD14-KO macrophages. However, LPS at 1,000 ng/ml induced TNF-α and MnSOD mRNAs equally in macrophages from CD14-KO and control mice. LPS (1, 10, or 1,000 ng/ml) failed to induce TNF-α or MnSOD mRNA and failed to activate nuclear factor-κB in C3H/HeJ or C57BL/10ScCr macrophages. Measurements of TNF-α and MnSOD enzyme activity paralleled TNF-α and MnSOD mRNA levels. These data demonstrate that, like TNF-α, induction of MnSOD by LPS is mediated by mCD14 and TLR4 in murine macrophages.
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MESH Headings
- Animals
- Drosophila Proteins
- Gene Deletion
- Gene Expression Regulation, Enzymologic/drug effects
- Gene Expression Regulation, Enzymologic/physiology
- Lipopolysaccharide Receptors/genetics
- Lipopolysaccharide Receptors/metabolism
- Lipopolysaccharides/pharmacology
- Macrophages, Peritoneal/drug effects
- Macrophages, Peritoneal/enzymology
- Membrane Glycoproteins/metabolism
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C3H
- Mice, Inbred C57BL
- Mice, Knockout
- NF-kappa B/metabolism
- RNA, Messenger/metabolism
- Receptors, Cell Surface/metabolism
- Superoxide Dismutase/genetics
- Superoxide Dismutase/metabolism
- Toll-Like Receptor 4
- Toll-Like Receptors
- Tumor Necrosis Factor-alpha/genetics
- Tumor Necrosis Factor-alpha/metabolism
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Affiliation(s)
- M F Tsan
- Research Service, Stratton Veterans Affairs Medical Center, Albany, NY 12208, USA.
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38
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Christensen PR, Bandfield JL, Smith MD, Hamilton VE, Clark RN. Identification of a basaltic component on the Martian surface from Thermal Emission Spectrometer data. ACTA ACUST UNITED AC 2000. [DOI: 10.1029/1999je001127] [Citation(s) in RCA: 215] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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39
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Carlson RW, Anderson MS, Johnson RE, Smythe WD, Hendrix AR, Barth CA, Soderblom LA, Hansen GB, McCord TB, Dalton JB, Clark RN, Shirley JH, Ocampo AC, Matson DL. Hydrogen peroxide on the surface of Europa. Science 1999; 283:2062-4. [PMID: 10092224 DOI: 10.1126/science.283.5410.2062] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Spatially resolved infrared and ultraviolet wavelength spectra of Europa's leading, anti-jovian quadrant observed from the Galileo spacecraft show absorption features resulting from hydrogen peroxide. Comparisons with laboratory measurements indicate surface hydrogen peroxide concentrations of about 0.13 percent, by number, relative to water ice. The inferred abundance is consistent with radiolytic production of hydrogen peroxide by intense energetic particle bombardment and demonstrates that Europa's surface chemistry is dominated by radiolysis.
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Affiliation(s)
- R W Carlson
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA.
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40
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Christensen PR, Anderson DL, Chase SC, Clancy RT, Clark RN, Conrath BJ, Kieffer HH, Kuzmin RO, Malin MC, Pearl JC, Roush TL, Smith MD. Results from the Mars Global Surveyor Thermal Emission Spectrometer. Science 1998; 279:1692-8. [PMID: 9497282 DOI: 10.1126/science.279.5357.1692] [Citation(s) in RCA: 175] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The Thermal Emission Spectrometer spectra of low albedo surface materials suggests that a four to one mixture of pyroxene to plagioclase, together with about a 35 percent dust component provides the best fit to the spectrum. Qualitative upper limits can be placed on the concentration of carbonates (<10 percent), olivine (<10 percent), clay minerals (<20 percent), and quartz (<5 percent) in the limited regions observed. Limb observations in the northern hemisphere reveal low-lying dust hazes and detached water-ice clouds at altitudes up to 55 kilometers. At an aerocentric longitude of 224 degrees a major dust storm developed in the Noachis Terra region. The south polar cap retreat was similar to that observed by Viking.
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41
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McCord TB, Carlson RW, Smythe WD, Hansen GB, Clark RN, Hibbitts CA, Fanale FP, Granahan JC, Segura M, Matson DL, Johnson TV, Martin PD. Organics and other molecules in the surfaces of Callisto and Ganymede. Science 1997; 278:271-5. [PMID: 9323203 DOI: 10.1126/science.278.5336.271] [Citation(s) in RCA: 139] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Five absorption features are reported at wavelengths of 3.4, 3.88, 4. 05, 4.25, and 4.57 micrometers in the surface materials of the Galilean satellites Callisto and Ganymede from analysis of reflectance spectra returned by the Galileo mission near-infrared mapping spectrometer. Candidate materials include CO2, organic materials (such as tholins containing C(triple bond)N and C-H), SO2, and compounds containing an SH-functional group; CO2, SO2, and perhaps cyanogen [(CN)2] may be present within the surface material itself as collections of a few molecules each. The spectra indicate that the primary surface constituents are water ice and hydrated minerals.
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Affiliation(s)
- T B McCord
- Hawaii Institute of Geophysics and Planetology, University of Hawaii, Honolulu, HI 96822, USA.
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42
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Abstract
Recent studies indicate that an increase in serotonergic (5-HT) activity in the nucleus accumbens (NAc) produces an increase in dopamine (DA) release, providing a possible mechanism for the involvement of DA in the therapeutic action of selective serotonin reuptake inhibitor (SSRI) antidepressants. However, acutely administered fluoxetine (2.5, 5.0, or 10.0 mg/kg, i.p.) failed to elevate extracellular levels of DA, or its metabolites in the NAc or caudate-putamen (CP). In fact, the highest dose produced a small (20%) decrease in DA levels in the NAc. Extracellular levels of the 5-HT metabolite 5HIAA were consistently decreased at all doses of fluoxetine in both structures. Since SSRIs generally require several weeks of treatment to be effective clinically, a second experiment examined the effect of chronic administration of fluoxetine. Chronic (21 day) daily treatment with 5 mg/kg had no effect on NAc basal levels of DA, DA metabolites, or 5HIAA, relative to a saline-treated control group. Finally, pretreatment with fluoxetine appeared to slightly enhance the elevation of NAc DA induced by an injection of cocaine (10 mg/kg, i.p.), an effect that was not quite significant (P < .06). In conclusion, the 5-HT-induced facilitation of NAc DA neurotransmission described in the literature may not be relevant to the therapeutic action of fluoxetine.
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Affiliation(s)
- R N Clark
- Department of Psychiatry and Behavioral Sciences, State University of New York at Stony Brook 11794, USA
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43
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Calvin WM, Clark RN, Brown RH, Spencer JR. Spectra of the icy Galilean satellites from 0.2 to 5μm: A compilation, new observations, and a recent summary. ACTA ACUST UNITED AC 1995. [DOI: 10.1029/94je03349] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Calvin WM, King TVV, Clark RN. Hydrous carbonates on Mars?: Evidence from Mariner 6/7 infrared spectrometer and ground-based telescopic spectra. ACTA ACUST UNITED AC 1994. [DOI: 10.1029/94je01090] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Abstract
Spectra obtained from recent telescopic observation of 1-Ceres and laboratory measurements and theoretical calculations of three component mixtures of Ceres analog material suggest that an ammoniated phyllosilicate is present on the surface of the asteroid, rather than H(2)O frost as had been previously reported. The presence of an ammoniated phyllosilicate, most likely ammoniated saponite, on the surface of Ceres implies that secondary temperatures could not have exceeded 400 kelvin.
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Christensen PR, Anderson DL, Chase SC, Clark RN, Kieffer HH, Malin MC, Pearl JC, Carpenter J, Bandiera N, Brown FG, Silverman S. Thermal emission spectrometer experiment: Mars Observer mission. ACTA ACUST UNITED AC 1992. [DOI: 10.1029/92je00453] [Citation(s) in RCA: 230] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Abstract
This paper has presented the characteristic features of those types of dwarfism that are manifest at birth. This information has been presented in a fashion that should assist the pediatrician in arriving at an appropriate diagnosis without excessive delay or extensive diagnostic studies. However, variable expressivity may result in subtle presentation and, in those cases, diagnosis may be more challenging.
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Affiliation(s)
- R N Clark
- Department of Orthopedics, Columbus Children's Hospital, Ohio 43205
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Clark RN, Swayze GA, Singer RB, Pollack JB. High-resolution reflectance spectra of Mars in the 2.3-μm region: Evidence for the mineral scapolite. ACTA ACUST UNITED AC 1990. [DOI: 10.1029/jb095ib09p14463] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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