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  • Astronomy  (1,431)
  • Geophysics  (1,332)
  • Cell & Developmental Biology
  • Fisheries
  • 2000-2004  (2,790)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Bulletin of engineering geology and the environment 58 (2000), S. 125-132 
    ISSN: 1435-9537
    Keywords: Key words Sand ; Fill ; Geophysics ; Nigeria ; Coastal ; Reclamation ; Mots clés Sable ; Remblai ; Geophysique ; Nigeria ; Cótier ; Assainissement
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Description / Table of Contents: Résumé Il est prévu d'aménager une région de la péninsule de Lekki, de l'État de Lagos. Ainsi, des études ont été entreprises afin de préciser une coupe géologique et géo-électrique des terrains superficiels: identifier les séries sableuses, déterminer leurs épaisseurs et préparer une carte des caractéristiques géomorphologiques du terrain original, avant remblaiement. Des sondages électriques verticaux et des essais au pénétromètre ont été réalisés sur un secteur sableux de la péninsule de Lekki. Les données obtenues ont montré une bonne corrélation entre les caractéristiques géomorphologiques issues de photo-interprétations et celles résultant de cartes établies à partir des résultats de prospection électrique et d'essais au pénétromètre.
    Notes: Abstract  It was hoped to develop an area of reclaimed land on the Lekki Peninsula of Lagos State. An investigation was therefore carried out in order to establish the subsurface geological/geo-electrical sequence; to identify the sand columns and determine their thickness and prepare a map of the geomorphological features of the original, pre-fill terrain. Vertical electrical resistivity soundings (VES) and penetrometer tests were carried out in a sand filled segment of the Lekki Peninsula. The information obtained showed a good correlation between the geomorphological features as interpreted from the aerial photographs and those identified from maps derived from the VES/penetrometer results.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Agriculture and human values 17 (2000), S. 125-139 
    ISSN: 1572-8366
    Keywords: Environment ; Fisheries ; Fordism ; Nation-State ; Regulation ; Supranational State ; Transnational corporations ; Transnational State
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract This analysis uses an analytical frameworkgrounded in political economy perspectives of theglobalization of the agro-food sector combined with acase study approach focusing on the Marine StewardshipCouncil (MSC) to inform discussions regarding thecharacteristics of societal regulation in thepost-Fordist era. More specifically, this analysisuses the case of the emergence of the MSC toinvestigate propositions regarding the existence of,and location of, nascent forms of a transnationalState. The MSC proposes to regulate the certificationof sustainable fisheries at the global level throughan eco-labeling program. The MSC was created in 1996by the transnational environmental organization theWorld Wildlife Fund and the transnational corporationUnilever. The emergence of the MSC has generatedheated discussion in fisheries management circles thatis in general divided along North/South lines. Thisanalysis indicates that the case of the MSC providesvaluable insights into the possible characteristics ofsupranational regulatory mechanisms that might emulatethe role of the nation-State in the post-Fordist era.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Surveys in geophysics 21 (2000), S. 423-448 
    ISSN: 1573-0956
    Keywords: Geophysics ; seismic ; electromagnetic ; geo-electric ; resistivity ; self-potential ; gravity ; boundary ; property ; slope stability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract A pre-requisite in slope stability analyses is that the internal structure and the mechanical properties of the soil or rock mass of the slope, are known or can be estimated with a reasonable degree of certainty. Geophysical methods to determine the internal structure of a soil or rock mass may be used for this purpose. Various geophysical methods and their merits for slope stability analyses are discussed. Seismic methods are often the most suitable because the measurements depend on the mechanical properties that are also important in the mechanical calculation of slope stability analyses. Other geophysical methods, such as electromagnetic, electric resistivity, self-potential, and gravity methods, may be useful to determine the internal structure, but require a correlation of found boundaries with mechanical properties.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Bulletin of engineering geology and the environment 59 (2000), S. 157-169 
    ISSN: 1435-9537
    Keywords: Mots clés Lyon–Turin ; Tunnel profond ; Reconnaissances géologiques ; Géophysique ; Forages ; Key words Lyons–Turin ; Deep tunnel ; Geological surveys ; Geophysics ; Boreholes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Description / Table of Contents: Abstract  This article presents the evolution of a geological, geotechnical and geophysical survey system for tunnel projects, using the Ambin Tunnel as an example. After a short introduction to the Lyons–Turin project, the paper describes in chronological order the systems and methods used to obtain geological and geotechnical information. Finally, the paper examines the modifications made to this particular survey programme as a result of the data obtained. The consequences for the evolution of the provisional layout of the tunnel are examined. The project to construct a new Lyons–Turin rail connection is part of the European transport scheme and is a key element in the Trans-European Network. It is one of the 14 priority projects of the European Union. This new link is of great importance for passenger transportation between France and Italy in terms of the potential reduction in journey time; the travel time from Lyons to Turin, instead of the current 3 h 55 min, being reduced to 1 h 20 min. It will also accelerate the transportation of goods. Thus, it will provide the best solution to the problems of transalpine traffic congestion and enhance environmental protection. The key element in the international section of this new link is the Ambin Tunnel, which is over 52 km long, running between Saint Jean de Maurienne (France) and Susa-Bussoleno (Italy). The tunnel will go through the main geological units of the Western Alps from the ultra Dauphinese area (external zone) to the Piemontese area after cutting through the Brianconese reliefs (inner zone). Since 1990, an extensive site investigation survey has been conducted by the SNCF (the French national railway company) and the FS (the Italian 'Ferrovie dello Stato'). Since 1994, this survey has been undertaken by the European Group of Economic Interest, Alpetunnel GEIE. The investigation aimed to accurately define the layout of the tunnel and to reduce as many uncertainties as possible with regard to conditions, time and cost of building. The survey initially utilised information on ground conditions from detailed geological maps and air photographs, allowing the construction of a provisional geological cross section of the tunnel. This cross section highlighted a few areas that were poorly understood. These areas were then studied using seismic refraction and reflection, often in tandem with the drilling of boreholes for increased accuracy. Many boreholes have been drilled to determine the geotechnical characteristics in addition to understanding the geology. Many tests and in-situ measurements have also been undertaken to study the hydrogeological and geotechnical conditions in the mountains that will be bored through. In 1999 and 2000, further drilling will be undertaken in areas requiring more detailed study. Also two directional drilling projects will be started vertically and then run obliquely until reaching the horizontal. This will produce more than 1000 m of horizontal core, allowing a better knowledge of the nature of the ground along the axis of the tunnel to be gained, including geotechnical measurements, hydrogeological data and in-situ geotechnical conditions. Later on, these studies will be extended to allow the construction of three or four survey galleries with the same dimensions as the tunnel in order to check and test the in-situ rocks. Some surveys have been changed midstream as a result of initial results. For example, deeper drilling was undertaken following the realisation that a seismic reflector was present a few metres below . It has also proved necessary to change the layout of the survey gallery at Modane and to change its cross section after the results of the first set of boreholes were analysed. Layers of karst, water-filled cavities, soft ground and flowing water were all found. The layout of the tunnel itself has been changed in several places following the results of the boreholes, seismic data or geotechnical tests. Examples include the first mile of the French side, several miles in the Brianconese coal measures, and the underground service installations. These results have led to an increased construction of survey galleries.
    Notes: Resumé Cet article a pour but de présenter l'évolution des reconnaissances géologique, géotechnique et géophysique menées sur un projet de tunnel, à travers l'exemple concret du tunnel d'Ambin, maillon clé de la partie internationale du projet de nouvelle liaison ferroviaire transalpine Lyon-Turin. A travers la description et les commentaires des résultats obtenus par plus de 80 forages (de 50 à 1520 m de longueur), plus de 100 km de sismique de surface et de la sismique de puits réalisée dans une trentaine de forages, nous montrons la progression et l'adaptation des reconnaissances dans une suite logique d'investigations. Nous présentons également les adaptations apportées en cours d'investigation, entreprises en temps réel au vu des premiers résultats, ainsi que les conséquences sur l'évolution du tracé prévisionnel du tunnel et de certaines galeries de reconnaissances.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Environment, development and sustainability 2 (2000), S. 277-304 
    ISSN: 1573-2975
    Keywords: Systems of Knowledge ; Local Knowledge ; Fisheries ; Resource Management
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Sociology
    Notes: Abstract During the last 20 years, the existence of rich systems of local knowledge, and their vital support to resource use and management regimes, has been demonstrated in a wide range of biological, physical and geographical domains, such as agriculture, animal husbandry, forestry and agroforestry, medicine, and marine science and fisheries. Local knowledge includes empirical and practical components that are fundamental to sustainable resource management. Among coastal-marine fishers, for example, regular catches and, often, long-term resource sustainment are ensured through the application of knowledge that encompasses empirical information on fish behaviour, marine physical environments, fish habitats and the interactions among ecosystem components, as well as complex fish taxonomies. Local knowledge is therefore an important cultural resource that guides and sustains the operation of customary management systems. The sets of rules that compose a fisheries management system derive directly from local concepts and knowledge of the resources on which the fishery is based. Beyond the practical and the empirical, it is essential to recognise the fundamental socio-cultural importance of local knowledge to any society. It is through knowledge transmission and socialisation that worldviews are constructed, social institutions perpetuated, customary practices established, and social roles defined. In this manner, local knowledge and its transmission, shape society and culture, and culture and society shape knowledge. Local knowledge is of great potential practical value. It can provide an important information base for local resources management, especially in the tropics, where conventionally-used data are usually scarce to non-existent, as well as providing a shortcut to pinpoint essential scientific research needs. To be useful for resources management, however, it must be systematically collected and scientifically verified, before being blended with complementary information derived from Western-based sciences. But local knowledge should not be looked on with only a short-term utilitarian eye. Arguments widely accepted for conserving biodiversity, for example, are also applicable to the intellectual cultural diversity encompassed in local knowledge systems: they should be conserved because their utility may only be revealed at some later date or owing to their intrinsic value as part of the world's global heritage. At least in cultures with a Western liberal tradition, more than lip-service is now being paid to alternative systems of knowledge. The denigration of alternative knowledge systems as backward, inefficient, inferior, and founded on myth and ignorance has recently begun to change. Many such practices are a logical, sophisticated and often still-evolving adaptation to risk, based on generations of empirical experience and arranged according to principles, philosophies and institutions that are radically different from those prevailing in Western scientific circles, and hence all-but incomprehensible to them. But steadfastly held prejudices remain powerful. In this presentation I describe the 'design principles' of local knowledge systems, with particular reference to coastal-marine fishing communities, and their social and practical usefulness. I then examine the economic, ideological and institutional factors that combine to perpetuate the marginalisation and neglect of local knowledge, and discuss some of the requirements for applying local knowledge in modern management.
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  • 6
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    In:  J. Geophys. Res., London, Am. Soc. Mech. Eng., vol. 107, no. B7, pp. ESE 4-1 to ESE 4-18, pp. 2147, (ISBN: 0534351875, 2nd edition)
    Publication Date: 2002
    Keywords: Seismology ; Three dimensional ; Dynamic ; Source ; Modelling ; Fracture ; 7209 ; Earthquake ; dynamics ; and ; mechanics ; 3230 ; Mathematical ; Geophysics: ; Numerical ; solutions ; 7260 ; Seismology: ; Theory ; and ; modeling ; 7299 ; 3299 ; Mathematical ; Geophysics ; JGR
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  • 7
    Publication Date: 2003-10-04
    Description: Arecibo radar observations of Titan at 13-centimeter wavelength indicate that most of the echo power is in a diffusely scattered component but that a small specular component is present for about 75% of the subearth locations observed. These specular echoes have properties consistent with those expected for areas of liquid hydrocarbons. Knowledge of the areal extent and depth of any deposits of liquid hydrocarbons could strongly constrain the history of Titan's atmosphere and surface.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Campbell, Donald B -- Black, Gregory J -- Carter, Lynn M -- Ostro, Steven J -- New York, N.Y. -- Science. 2003 Oct 17;302(5644):431-4. Epub 2003 Oct 2.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉National Astronomy and Ionosphere Center and Department of Astronomy, Space Sciences Building, Cornell University, Ithaca, NY 14853, USA. campbell@astro.cornell.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/14526087" target="_blank"〉PubMed〈/a〉
    Keywords: Astronomical Phenomena ; Astronomy ; Atmosphere ; Extraterrestrial Environment ; *Hydrocarbons ; Ice ; Radar ; *Saturn ; Water
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 8
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2003-10-11
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Stone, Richard -- New York, N.Y. -- Science. 2003 Oct 10;302(5643):221-2.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/14551417" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Ecosystem ; *Eels/growth & development/physiology ; Fisheries ; Fresh Water ; Oceans and Seas ; Population Density ; Reproduction ; Seawater
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 9
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2003-08-23
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Malakoff, David -- New York, N.Y. -- Science. 2003 Aug 22;301(5636):1034-7.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/12933987" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Anthozoa ; Atlantic Ocean ; Conservation of Natural Resources ; *Ecosystem ; Environment ; Fisheries ; *Fishes ; Geologic Sediments ; *Marine Biology ; Pacific Ocean ; *Seawater
    Print ISSN: 0036-8075
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    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 10
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2000-06-08
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Normile, D -- New York, N.Y. -- Science. 2000 May 19;288(5469):1165.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/10841732" target="_blank"〉PubMed〈/a〉
    Keywords: *Academies and Institutes/economics ; Animals ; Astronomical Phenomena ; Astronomy ; Chloroplasts/genetics ; Drosophila/genetics ; Interferometry ; *Molecular Biology/economics ; Physical Phenomena ; Physics ; *Research/economics ; Research Support as Topic ; Taiwan
    Print ISSN: 0036-8075
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  • 11
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2000-08-19
    Description: At a press conference on 27 July, the National Marine Fisheries Service (NMFS) released a long-awaited plan to save the Columbia River's endangered salmon by restoring fish habitat, overhauling hatcheries, limiting harvest, and improving river flow. What the plan did not do, however, was call for immediate breaching of four dams on the Snake River, the Columbia's major tributary--an option that has been the subject of a nationwide environmental crusade. The NMFS will hold that option in abeyance while it sees whether the less drastic measures will do the trick. Responses from both sides were immediate and outraged.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Mann, C C -- Plummer, M L -- New York, N.Y. -- Science. 2000 Aug 4;289(5480):716-9.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/10950712" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Conservation of Natural Resources ; *Ecosystem ; Fisheries ; Fresh Water ; Government Agencies ; Northwestern United States ; *Salmon
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    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 12
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2001-12-26
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉New York, N.Y. -- Science. 2001 Dec 21;294(5551):2444.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/11752539" target="_blank"〉PubMed〈/a〉
    Keywords: Astronomical Phenomena ; Astronomy ; Biochemical Phenomena ; Biochemistry ; Computer Simulation ; Embryo, Mammalian/cytology ; Genetics, Medical ; Humans ; Microscopy, Electron ; Optics and Photonics ; Proteins/physiology ; Proteome ; *Research ; *Science ; Stem Cells
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    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 13
    Publication Date: 2001-08-18
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Magnuson, J J -- Safina, C -- Sissenwine, M P -- New York, N.Y. -- Science. 2001 Aug 17;293(5533):1267-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Center for Limnology, University of Wisconsin, Madison, WI 53706, USA. jmagnuson@mhub.limnology.wisc.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/11509715" target="_blank"〉PubMed〈/a〉
    Keywords: Animal Identification Systems ; Animals ; Atlantic Ocean ; *Behavior, Animal ; Body Temperature ; *Conservation of Natural Resources ; Diving ; *Ecosystem ; Fisheries ; Population Dynamics ; Reproduction ; Swimming ; Tuna/genetics/*physiology
    Print ISSN: 0036-8075
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    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 14
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2001-08-11
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Robert, F -- New York, N.Y. -- Science. 2001 Aug 10;293(5532):1056-8.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/11498566" target="_blank"〉PubMed〈/a〉
    Keywords: Astronomical Phenomena ; Astronomy ; Atmosphere ; Deuterium ; *Earth (Planet) ; *Evolution, Planetary ; *Hydrogen ; Mars ; *Meteoroids ; Silicates/chemistry ; *Water
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    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 15
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2001-10-13
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Malakoff, D -- New York, N.Y. -- Science. 2001 Oct 12;294(5541):292-3.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/11598283" target="_blank"〉PubMed〈/a〉
    Keywords: Astronomy ; Biological Evolution ; Ecology ; History, 20th Century ; Humans ; *Nobel Prize ; Psychology
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  • 16
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2001-03-20
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Malakoff, D -- New York, N.Y. -- Science. 2001 Jan 12;291(5502):227-9.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/11253825" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Fisheries ; *Homing Behavior ; Isotopes ; Otolithic Membrane/*chemistry ; Perciformes/*physiology ; Population Dynamics ; Reproduction ; United States
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  • 17
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2001-02-24
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉New York, N.Y. -- Science. 2000 Dec 22;290(5500):2223.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/11188704" target="_blank"〉PubMed〈/a〉
    Keywords: Alzheimer Disease ; Astronomical Phenomena ; Astronomy ; Computing Methodologies ; Ecosystem ; Forecasting ; Humans ; Molecular Biology ; Poliomyelitis/epidemiology ; *Research/trends
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  • 18
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2001-02-24
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Collie, J -- Saila, S -- Walters, C -- Carpenter, S -- New York, N.Y. -- Science. 2000 Nov 3;290(5493):933-4.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/11184733" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Conservation of Natural Resources ; *Ecosystem ; Fisheries ; Fresh Water ; Government Agencies ; Models, Biological ; Northwestern United States ; Population Dynamics ; *Salmon/physiology
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  • 19
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2002-12-21
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉New York, N.Y. -- Science. 2002 Dec 20;298(5602):2297-303.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/12493876" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Astronomical Phenomena ; Astronomy ; Biological Evolution ; Cosmic Radiation ; Elementary Particles ; Genome ; Hominidae ; Humans ; Ion Channels/physiology ; Lasers ; Light ; Microwaves ; Motion Pictures as Topic ; Optics and Photonics ; Retinal Ganglion Cells/physiology ; Rod Opsins/physiology ; *Science ; Sequence Analysis, DNA ; Temperature ; Tomography/methods
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  • 20
    Publication Date: 2000-10-29
    Description: The effects of climate variability on Pacific salmon abundance are uncertain because historical records are short and are complicated by commercial harvesting and habitat alteration. We use lake sediment records of delta15N and biological indicators to reconstruct sockeye salmon abundance in the Bristol Bay and Kodiak Island regions of Alaska over the past 300 years. Marked shifts in populations occurred over decades during this period, and some pronounced changes appear to be related to climatic change. Variations in salmon returns due to climate or harvesting can have strong impacts on sockeye nursery lake productivity in systems where adult salmon carcasses are important nutrient sources.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Finney, B P -- Gregory-Eaves, I -- Sweetman, J -- Douglas, M S -- Smol, J P -- New York, N.Y. -- Science. 2000 Oct 27;290(5492):795-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institute of Marine Science, University of Alaska Fairbanks, Fairbanks, AK 99775, USA. finney@ims.uaf.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/11052941" target="_blank"〉PubMed〈/a〉
    Keywords: Alaska ; Animals ; *Climate ; Diatoms ; *Ecosystem ; Fisheries ; Fresh Water ; Geologic Sediments/chemistry ; Industry ; Nitrogen Isotopes/analysis ; Pacific Ocean ; Plankton ; Salmon/*physiology ; Temperature
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  • 21
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2000-08-05
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Muro, M -- New York, N.Y. -- Science. 2000 Jul 14;289(5477):228.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/10917838" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Arizona ; Astronomical Phenomena ; Astronomy ; Conservation of Natural Resources ; Population Dynamics ; *Sciuridae
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2001-07-28
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Zimmer, C -- New York, N.Y. -- Science. 2001 Jul 27;293(5530):627-8.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/11474097" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Cnidaria ; *Ecosystem ; Eutrophication ; Fisheries ; International Cooperation ; Israel ; Jordan ; Marine Biology ; Oceans and Seas ; Time Factors ; United States
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2002-08-07
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ajayi, Thomas -- Sherman, Kenneth -- Tang, Qisheng -- New York, N.Y. -- Science. 2002 Aug 2;297(5582):772.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/12162321" target="_blank"〉PubMed〈/a〉
    Keywords: Biomass ; Conservation of Natural Resources/*economics/*methods/trends ; *Ecosystem ; Europe ; Fisheries ; International Cooperation ; *Marine Biology/economics/trends ; North America ; Water Pollution/prevention & control
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2000-01-15
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉New York, N.Y. -- Science. 1999 Dec 17;286(5448):2239-43.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/10636773" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Astronomical Phenomena ; Astronomy ; Eukaryotic Cells ; Genome ; Memory ; Nuclear Physics ; Photons ; *Research ; Ribosomes/chemistry/ultrastructure ; Sequence Analysis, DNA
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2001-02-24
    Description: Using a novel technique, described on page 795, paleoceanographers have been able to chart the abundance of sockeye salmon in the Bristol Bay and Kodiak Island regions of Alaska over the past 300 years--by far the most complete record yet. Through time, they found, sockeye populations have alternately soared and slipped, following natural climate variations--well before commercial fishers began throwing nets over the sides of boats.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Brown, K -- New York, N.Y. -- Science. 2000 Oct 27;290(5492):685-6.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/11184190" target="_blank"〉PubMed〈/a〉
    Keywords: Alaska ; Animals ; *Climate ; *Ecosystem ; Fisheries ; Fresh Water ; Geologic Sediments/chemistry ; Nitrogen Isotopes/analysis ; Pacific Ocean ; Salmon/*physiology ; Temperature
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2000-05-08
    Description: Fish faunas across the continental United States have become more similar through time because of widespread introductions of a group of cosmopolitan species intended to enhance food and sport fisheries. On average, pairs of states have 15.4 more species in common now than before European settlement of North America. The 89 pairs of states that formerly had no species in common now share an average of 25.2 species. Introductions have played a larger role than extirpations in homogenizing fish faunas. Western and New England states have received the most introductions, which is a reflection of the small number of native fishes in these areas considered desirable gamefish by settlers.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Rahel, F J -- New York, N.Y. -- Science. 2000 May 5;288(5467):854-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071, USA. frahel@uwyo.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/10797007" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Ecosystem ; Fisheries ; *Fishes ; Species Specificity ; United States
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2001-02-24
    Description: Science recognizes nine other major discoveries on scales ranging from the cosmic to the quantum: Ribosome Revelations Fossil Find One Word--Organics New Cells for Old Water, Water, Everywhere Cosmic BOOMERANG Good Reception So NEAR ... Quantum Curiosities〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉New York, N.Y. -- Science. 2000 Dec 22;290(5500):2221-5.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/11188702" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Astronomical Phenomena ; Astronomy ; Cloning, Organism ; Electronics ; Humans ; Plastics ; Quantum Theory ; Receptors, Cytoplasmic and Nuclear/physiology ; *Research ; Ribosomes/chemistry/ultrastructure ; Stem Cells ; Water
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  • 28
    Publication Date: 2001-08-18
    Description: The deployment of electronic data storage tags that are surgically implanted or satellite-linked provides marine researchers with new ways to examine the movements, environmental preferences, and physiology of pelagic vertebrates. We report the results obtained from tagging of Atlantic bluefin tuna with implantable archival and pop-up satellite archival tags. The electronic tagging data provide insights into the seasonal movements and environmental preferences of this species. Bluefin tuna dive to depths of 〉1000 meters and maintain a warm body temperature. Western-tagged bluefin tuna make trans-Atlantic migrations and they frequent spawning grounds in the Gulf of Mexico and eastern Mediterranean. These data are critical for the future management and conservation of bluefin tuna in the Atlantic.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Block, B A -- Dewar, H -- Blackwell, S B -- Williams, T D -- Prince, E D -- Farwell, C J -- Boustany, A -- Teo, S L -- Seitz, A -- Walli, A -- Fudge, D -- New York, N.Y. -- Science. 2001 Aug 17;293(5533):1310-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Tuna Research and Conservation Center, Stanford University, Hopkins Marine Station, Oceanview Boulevard, Pacific Grove, CA 93950, USA. bblock@stanford.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/11509729" target="_blank"〉PubMed〈/a〉
    Keywords: Animal Identification Systems ; Animals ; Atlantic Ocean ; *Behavior, Animal ; Body Temperature ; Conservation of Natural Resources ; Diving ; *Ecosystem ; Female ; Fisheries ; Male ; Reproduction ; Seasons ; Swimming ; Temperature ; Tuna/*physiology
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  • 29
    Publication Date: 2001-09-15
    Description: Recent advances in machine learning methods, along with successful applications across a wide variety of fields such as planetary science and bioinformatics, promise powerful new tools for practicing scientists. This viewpoint highlights some useful characteristics of modern machine learning methods and their relevance to scientific applications. We conclude with some speculations on near-term progress and promising directions.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Mjolsness, E -- DeCoste, D -- New York, N.Y. -- Science. 2001 Sep 14;293(5537):2051-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Machine Learning Systems Group, Jet Propulsion Laboratory/California Institute of Technology, Pasadena, CA, 91109, USA. mjolsness@jpl.nasa.gov〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/11557883" target="_blank"〉PubMed〈/a〉
    Keywords: Algorithms ; Animals ; *Artificial Intelligence ; Astronomical Phenomena ; Astronomy ; Cluster Analysis ; *Computational Biology ; Computer Simulation ; Gene Expression Profiling ; Gene Expression Regulation ; Image Processing, Computer-Assisted ; Neural Networks (Computer) ; Physical Phenomena ; Physics ; Robotics
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2002-12-21
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉New York, N.Y. -- Science. 2002 Dec 20;298(5602):2299.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/12493878" target="_blank"〉PubMed〈/a〉
    Keywords: Astronomical Phenomena ; Astronomy ; Diagnostic Imaging ; Embryo, Mammalian/cytology ; Genetics, Medical ; Haplotypes ; Humans ; Optics and Photonics ; Proteomics ; *Science ; Stem Cells
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2002-12-21
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉New York, N.Y. -- Science. 2002 Dec 20;298(5602):2298.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/12493877" target="_blank"〉PubMed〈/a〉
    Keywords: Astronomical Phenomena ; Astronomy ; Biological Evolution ; Budgets ; Climate ; Elementary Particles ; Extraterrestrial Environment ; Ice ; Science/economics/*trends
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2003-10-04
    Description: It has long been known that Saturn's largest moon, Titan, has a thick nitrogen atmosphere, which obscures the underlying surface. In his Perspective, Lorenz highlights the report by Campbell et al., who have used the giant Arecibo and Green Bank radio telescopes as a radar to probe Titan's hidden surface. The surface appears to be distinct from those of the icy satellites of Jupiter, in both brightness and polarization. The new data show sharp spikes in the reflected microwave spectrum, indicating large, smooth areas of radar-dark material. These features suggest the widespread existence of lakes or seas of liquid hydrocarbons on Titan.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lorenz, Ralph -- New York, N.Y. -- Science. 2003 Oct 17;302(5644):403-4. Epub 2003 Oct 2.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, USA. rlorenz@lpl.arizona.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/14526089" target="_blank"〉PubMed〈/a〉
    Keywords: Astronomical Phenomena ; Astronomy ; Atmosphere ; Extraterrestrial Environment ; *Hydrocarbons ; Ice ; Radar ; *Saturn ; Water
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2003-07-26
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lunine, Jonathan -- New York, N.Y. -- Science. 2003 Jul 25;301(5632):462; author reply 462.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/12881549" target="_blank"〉PubMed〈/a〉
    Keywords: Astronomical Phenomena ; Astronomy ; *Evolution, Planetary ; Jupiter
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2003-12-20
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉New York, N.Y. -- Science. 2003 Dec 19;302(5653):2041.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/14684789" target="_blank"〉PubMed〈/a〉
    Keywords: Astronomical Phenomena ; Astronomy ; Climate ; Elementary Particles ; Forecasting ; Genomics ; Research Support as Topic ; Science/*trends
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  • 35
    Publication Date: 2003-07-05
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sanchirico, James N -- Stoffle, Richard -- Broad, Kenny -- Talaue-McManus, Liana -- New York, N.Y. -- Science. 2003 Jul 4;301(5629):47-9; author reply 47-9.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/12843376" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; California ; *Conservation of Natural Resources ; *Ecosystem ; Fisheries ; *Fishes ; Humans ; Seawater
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  • 36
    Publication Date: 2003-06-07
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Irion, Robert -- New York, N.Y. -- Science. 2003 Jun 6;300(5625):1498.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/12791960" target="_blank"〉PubMed〈/a〉
    Keywords: Astronomical Phenomena ; Astronomy ; *Evolution, Planetary
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2003-04-05
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Service, Robert F -- New York, N.Y. -- Science. 2003 Apr 4;300(5616):36-9.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/12677035" target="_blank"〉PubMed〈/a〉
    Keywords: Agriculture ; Animals ; California ; *Conservation of Natural Resources ; *Cypriniformes/physiology ; *Ecology ; Ecosystem ; Environment ; Fisheries ; *Fresh Water ; Government Agencies ; National Academy of Sciences (U.S.) ; *Oncorhynchus kisutch/physiology ; Oregon ; United States ; Water Movements
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  • 38
    Publication Date: 2004-11-13
    Description: The multibillion-dollar trade in bushmeat is among the most immediate threats to the persistence of tropical vertebrates, but our understanding of its underlying drivers and effects on human welfare is limited by a lack of empirical data. We used 30 years of data from Ghana to link mammal declines to the bushmeat trade and to spatial and temporal changes in the availability of fish. We show that years of poor fish supply coincided with increased hunting in nature reserves and sharp declines in biomass of 41 wildlife species. Local market data provide evidence of a direct link between fish supply and subsequent bushmeat demand in villages and show bushmeat's role as a dietary staple in the region. Our results emphasize the urgent need to develop cheap protein alternatives to bushmeat and to improve fisheries management by foreign and domestic fleets to avert extinctions of tropical wildlife.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Brashares, Justin S -- Arcese, Peter -- Sam, Moses K -- Coppolillo, Peter B -- Sinclair, A R E -- Balmford, Andrew -- New York, N.Y. -- Science. 2004 Nov 12;306(5699):1180-3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Conservation Biology Group, Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK. brashares@nature.berkeley.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15539602" target="_blank"〉PubMed〈/a〉
    Keywords: Agriculture ; Animals ; *Animals, Wild ; Biodiversity ; Biomass ; Commerce ; Conservation of Natural Resources ; Fisheries ; *Fishes ; *Food Supply ; Ghana ; Humans ; *Mammals ; *Meat ; Population Density ; Population Dynamics
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2004-08-31
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Grimm, David -- New York, N.Y. -- Science. 2004 Aug 27;305(5688):1235.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15333821" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Biodiversity ; *Ecosystem ; Fisheries ; *Fishes ; Humans ; Population Density ; *Recreation ; United States
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  • 40
    Publication Date: 2004-09-14
    Description: It is now widely accepted that global warming is occurring, yet its effects on the world's largest ecosystem, the marine pelagic realm, are largely unknown. We show that sea surface warming in the Northeast Atlantic is accompanied by increasing phytoplankton abundance in cooler regions and decreasing phytoplankton abundance in warmer regions. This impact propagates up the food web (bottom-up control) through copepod herbivores to zooplankton carnivores because of tight trophic coupling. Future warming is therefore likely to alter the spatial distribution of primary and secondary pelagic production, affecting ecosystem services and placing additional stress on already-depleted fish and mammal populations.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Richardson, Anthony J -- Schoeman, David S -- New York, N.Y. -- Science. 2004 Sep 10;305(5690):1609-12.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Sir Alister Hardy Foundation for Ocean Science, The Laboratory, Citadel Hill, Plymouth, PL1 2PB, UK. anr@sahfos.ac.uk〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15361622" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Atlantic Ocean ; *Climate ; Copepoda/*growth & development ; *Ecosystem ; Fisheries ; Fishes ; *Food Chain ; Greenhouse Effect ; Meta-Analysis as Topic ; Phytoplankton/*growth & development ; Population Dynamics ; Seawater ; Temperature ; Zooplankton/*growth & development
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2004-08-25
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Proffitt, Fiona -- New York, N.Y. -- Science. 2004 Aug 20;305(5687):1090.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15326320" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Birds/*physiology ; *Ecosystem ; *Eels ; Fisheries ; Food Chain ; North Sea ; Plankton ; Population Density ; *Reproduction ; Scotland ; Seawater ; Temperature
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2004-06-26
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wright, Bruce A -- Okey, Thomas A -- New York, N.Y. -- Science. 2004 Jun 25;304(5679):1903.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15218125" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Conservation of Natural Resources ; *Ecosystem ; *Environment ; Fisheries ; Humans ; Information Dissemination ; Population Growth ; Public Policy
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2004-08-25
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Allison, Edward H -- Seeley, Janet A -- New York, N.Y. -- Science. 2004 Aug 20;305(5687):1104.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15326332" target="_blank"〉PubMed〈/a〉
    Keywords: Asia/epidemiology ; Female ; Fisheries ; HIV Infections/*epidemiology/transmission ; Humans ; Male ; Occupations ; Prevalence ; Sexual Partners ; *Transients and Migrants
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2003-05-10
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Zimmer, Carl -- New York, N.Y. -- Science. 2003 May 9;300(5621):895.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/12738833" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Biological Evolution ; Breeding ; *Conservation of Natural Resources ; Environment ; Fisheries ; *Fishes/genetics/growth & development/physiology ; Plant Development ; Reproduction ; *Selection, Genetic ; Sexual Maturation
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2004-07-27
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Rembold, Christopher M -- New York, N.Y. -- Science. 2004 Jul 23;305(5683):475; author reply 475.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15273376" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Coronary Artery Disease/mortality/*prevention & control ; *Diet ; Environmental Pollutants/toxicity ; Fatty Acids, Omega-3/*administration & dosage ; Fisheries ; *Food Contamination ; Humans ; Neoplasms/chemically induced/epidemiology ; Randomized Controlled Trials as Topic ; Risk Assessment ; *Salmon ; Toxicity Tests
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 46
    Publication Date: 2004-09-14
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Stokstad, Erik -- New York, N.Y. -- Science. 2004 Sep 10;305(5690):1548-9.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15361593" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Atlantic Ocean ; *Climate ; *Ecosystem ; Fisheries ; *Food Chain ; Phytoplankton/*growth & development ; Population Dynamics ; Seawater ; Temperature ; Zooplankton/*growth & development
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 47
    Publication Date: 2002-12-10
    Description: There is debate concerning the most effective conservation of marine biodiversity, especially regarding the appropriate location, size, and connectivity of marine reserves. We describe a means of establishing marine reserve networks by using optimization algorithms and multiple levels of information on biodiversity, ecological processes (spawning, recruitment, and larval connectivity), and socioeconomic factors in the Gulf of California. A network covering 40% of rocky reef habitat can fulfill many conservation goals while reducing social conflict. This quantitative approach provides a powerful tool for decision-makers tasked with siting marine reserves.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sala, Enric -- Aburto-Oropeza, Octavio -- Paredes, Gustavo -- Parra, Ivan -- Barrera, Juan C -- Dayton, Paul K -- New York, N.Y. -- Science. 2002 Dec 6;298(5600):1991-3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Center for Marine Biodiversity and Conservation, Scripps Institution of Oceanography, La Jolla, CA 92093, USA. esala@ucsd.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/12471258" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; California ; Computer Simulation ; *Conservation of Natural Resources ; *Ecosystem ; Environment ; Fisheries ; Fishes ; Invertebrates ; *Models, Biological ; *Seawater
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 48
    Publication Date: 2003-08-30
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Webster, Paul -- New York, N.Y. -- Science. 2003 Aug 29;301(5637):1167.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/12947169" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Conservation of Natural Resources/economics ; *Ecosystem ; *Environment ; Financial Support ; Fisheries ; Fresh Water ; Pacific Ocean ; Russia ; *Salmon ; United Nations/economics
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 49
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2004-01-01
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉New York, N.Y. -- Science. 2003 Dec 19;302(5653):2039-45.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/14700029" target="_blank"〉PubMed〈/a〉
    Keywords: Angiogenesis Inhibitors/therapeutic use ; Animals ; Astronomical Phenomena ; Astronomy ; Climate ; Germ Cells/cytology/physiology ; Humans ; Mental Disorders/etiology/genetics ; Neoplasms/blood supply/drug therapy ; Physical Phenomena ; Physics ; RNA, Antisense ; *Science/trends ; Stem Cells/physiology ; Y Chromosome/genetics
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 50
    Publication Date: 2004-12-03
    Description: If one wanted to study Earth's core directly, one would have to drill through about 1,800 miles of solid rock to reach liquid core-keeping the tunnel from collapsing under pressures that are more than 1 million atmospheres and then sink an instrument package to the bottom that could operate at 8,000 F with 10,000 tons of force crushing every square inch of its surface. Even then, several of these tunnels would probably be needed to obtain enough data. Faced with difficult or impossible tasks such as these, scientists use other available sources of information - such as seismology, mineralogy, geomagnetism, geodesy, and, above all, physical principles - to derive a model of the core and, study it by running computer simulations. One NASA researcher is doing just that on NCCS computers. Physicist and applied mathematician Weijia Kuang, of the Space Geodesy Branch, and his collaborators at Goddard have what he calls the,"second - ever" working, usable, self-consistent, fully dynamic, three-dimensional geodynamic model (see "The Geodynamic Theory"). Kuang runs his model simulations on the supercomputers at the NCCS. He and Jeremy Bloxham, of Harvard University, developed the original version, written in Fortran 77, in 1996.
    Keywords: Geophysics
    Type: 1999 NCCS Highlights; 84-89
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  • 51
    Publication Date: 2004-12-03
    Description: For centuries, men have attempted to understand the climate system through observations obtained from Earth's surface. These observations yielded preliminary understanding of the ocean currents, tides, and prevailing winds using visual observation and simple mechanical tools as their instruments. Today's sensitive, downward-looking radar systems, called altimeters, onboard satellites can measure globally the precise height of the ocean surface. This surface is largely that of the equipotential gravity surface, called the geoid - the level surface to which the oceans would conform if there were no forces acting on them apart from gravity, as well as having a significant 1-2- meter-level signal arising from the motion of the ocean's currents.
    Keywords: Geophysics
    Type: 1999 NCCS Highlights; 78-83
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  • 52
    Publication Date: 2004-12-03
    Description: 'NASA is preparing to launch the Next Generation Space Telescope (NGST). This telescope will be larger than the Hubble Space Telescope, be launched on an Atlas missile rather than the Space Shuttle, have a segmented primary mirror, and be placed in a higher orbit. All these differences pose significant challenges.' This effort addresses the challenge of implementing an algorithm for aligning the segments of the primary mirror during the initial deployment that was designed by Philip Olivier and members of SOMTC (Space Optics Manufacturing Technology Center). The implementation was to be performed on the SIBOA (Systematic Image Based Optical Alignment) test bed. Unfortunately, hardware/software aspect concerning SIBOA and an extended time period for algorithm development prevented testing before the end of the study period. Properties of the digital camera were studied and understood, resulting in the current ability of selecting optimal settings regarding saturation. The study was successful in manually capturing several images of two stacked segments with various relative phases. These images can be used to calibrate the algorithm for future implementation. Currently the system is ready for testing.
    Keywords: Astronomy
    Type: Research Reports: 2001 NASA/ASEE Summer Faculty Fellowship Program; XLII-1 - XLII-5; NASA/CR-2002-211840
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  • 53
    Publication Date: 2004-12-03
    Description: At the end of World War II Duane Deming, an internationally known economist enunciated what later came to be called "Total Quality Management" (TQM). The basic thrust of this economic theory called for companies and governments to identify their customers and to do whatever was necessary to meet their demands and to keep them satisfied. It also called for companies to compete internally. That is, they were to build products that competed with their own so that they were always improving. Unfortunately most U.S. corporations failed to heed this advice. Consequently, the Japanese who actively sought Deming's advice and instituted it in their corporate planning, built an economy that outstripped that of the U.S. for the next three to four decades. Only after U.S. corporations reorganized and fashioned joint ventures which incorporated the tenets of TQM with their Japanese competitors did they start to catch up. Other institutions such as the U.S. government and its agencies and schools face the same problem. While the power of the U.S. government is in no danger of being usurped, its agencies and schools face real problems which can be traced back to not heeding Deming's advice. For example, the public schools are facing real pressure from private schools and home school families because they are not meeting the needs of the general public, Likewise, NASA and other government agencies find themselves shortchanged in funding because they have failed to convince the general public that their missions are important. In an attempt to convince the general public that its science mission is both interesting and important, in 1998 the Science Directorate at NASA's Marshall Space Flight Center (MSFC) instituted a new outreach effort using the interact to reach the general public as well as the students. They have called it 'Science@NASA'.
    Keywords: Astronomy
    Type: Research Reports: 2001 NASA/ASEE Summer Faculty Fellowship Program; XXIX-1 - XXIX-5; NASA/CR-2002-211840
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  • 54
    Publication Date: 2004-12-03
    Description: A new media calibration system (MCS) has been implemented at the Goldstone complex of the DSN (Deep Space Network). It is intended to calibrate the delay of radio signals imposed by the neutral atmosphere. The system provides periodic measurements of both the static dry and fluctuating wet components of this delay. In particular, the system will calibrate the fluctuations in line of sight path delay due to atmospheric water vapor that we believe will dominate the error budget for several radio science and radio astronomy experiments. We have compared two of these media calibration systems with a connected element interferometer on a 21 km baseline. In this report we describe a total of 30 observations in which a radio source was tracked for an hour or more and the delay residuals then calibrated using the MCS. The accuracy of the comparison appears to be limited by systematic errors in the interferometer, which are under investigation. However, our results do indicate that the MCS can meet or exceed the two-way Allan standard deviation specification of 1.5 x 10( exp -15) on time scales of 2,000 - 10,000 sec, as required by the Cassini GWE (Gravitational Wave Experiment) for two way Doppler tracking.
    Keywords: Geophysics
    Type: International VLBI Service for Geodesy and Astrometry General Meeting Proceeding; 194-198; NASA/CP-2002-210002
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  • 55
    Publication Date: 2004-12-03
    Description: We present geodetic results of a series of 30 VLBI experiments recorded in Mark 4 mode at rates of 128 and 256 Mbps. The formal uncertainties of UT1, polar motion, and nutation offsets derived from these experiments are better than the corresponding uncertainties from NEOS-A experiments by a factor of 1.3-2. Baseline length repeatability for the series of 32 experiments over a period of one year is about 0.9 ppb. For comparison, NEOS-A length repeatability is about 1.4 ppb. We will discuss optimal use of Mark 4 in the design of future observing networks.
    Keywords: Geophysics
    Type: International VLBI Service for Geodesy and Astrometry General Meeting Proceeding; 50-54; NASA/CP-2002-210002
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  • 56
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    In:  CASI
    Publication Date: 2004-12-03
    Description: The NASA Network includes nine NASA operated and partner operated stations covering North America, the west coast of South America, the Pacific, and Western Australia . A new station is presently being setup in South Africa and discussions are underway to add another station in Argentina. NASA SLR operations are supported by Honeywell Technical Solutions, Inc (HTSI), formally AlliedSignal Technical Services, The University of Texas, the University of Hawaii and Universidad Nacional de San Agustin.
    Keywords: Geophysics
    Type: International Laser Ranging Service (ILRS) 1999 Annual Report; 98-107; NASA/TP-2000-209969
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  • 57
    Publication Date: 2004-12-03
    Description: This report describes the organization, activities, meetings held and the current challenges of the Central Bureau of the ILRS.
    Keywords: Geophysics
    Type: International Laser Ranging Service (ILRS) 1999 Annual Report; 16-18; NASA/TP-2000-209969
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  • 58
    Publication Date: 2011-09-13
    Description: Analyses of laser ranges to the Moon are utilized for a broad range of investigations: lunar science, gravitational physics, geodesy, geodynamics and astronomy. Unique contributions from LLR include: detection of a molten lunar core; measurement of tidal dissipation in the Moon; an accurate test of the principle of equivalence for massive bodies (strong equivalence principle); and detection of lunar free librations. LLR analysis has provided tests of relativity, measurements of the Moon's tidal acceleration and the Earth s precession, and has provided orders-of-magnitude improvements in the accuracies of the lunar ephemeris and three-dimensional rotation. JPL has been active in all of these various LLR applications and supplies lunar and planetary ephemerides and lunar physical librations to the community.
    Keywords: Geophysics
    Type: International Laser Ranging Service (ILRS) 1999 Annual Report; 208-210; NASA/TP-2000-209969
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  • 59
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    In:  CASI
    Publication Date: 2011-09-13
    Description: The Crustal Dynamics Data Information System (CDDIS) has supported the archive and distribution of laser ranging data (both lunar and satellite) since its inception in 1982. This report summarizes the current and future plans of the CDDIS with respect to the International Laser Ranging Service (ILRS). Included here is background information about the CDDIS, its computer architecture, staffing, and archive contents, as well as future plans for the system within the ILRS.
    Keywords: Geophysics
    Type: International Laser Ranging Service (ILRS) 1999 Annual Report; 144-148; NASA/TP-2000-209969
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  • 60
    facet.materialart.
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    In:  CASI
    Publication Date: 2011-09-13
    Description: The NASA SLR Operational Center is responsible for: 1) NASA SLR network control, sustaining engineering, and logistics; 2) ILRS mission operations; and 3) ILRS and NASA SLR data operations. NASA SLR network control and sustaining engineering tasks include technical support, daily system performance monitoring, system scheduling, operator training, station status reporting, system relocation, logistics and support of the ILRS Networks and Engineering Working Group. These activities ensure the NASA SLR systems are meeting ILRS and NASA mission support requirements. ILRS mission operations tasks include mission planning, mission analysis, mission coordination, development of mission support plans, and support of the ILRS Missions Working Group. These activities ensure than new mission and campaign requirements are coordinated with the ILRS. Global Normal Points (NP) data, NASA SLR FullRate (FR) data, and satellite predictions are managed as part of data operations. Part of this operation includes supporting the ILRS Data Formats and Procedures Working Group. Global NP data operations consist of receipt, format and data integrity verification, archiving and merging. This activity culminates in the daily electronic transmission of NP files to the CDDIS. Currently of all these functions are automated. However, to ensure the timely and accurate flow of data, regular monitoring and maintenance of the operational software systems, computer systems and computer networking are performed. Tracking statistics between the stations and the data centers are compared periodically to eliminate lost data. Future activities in this area include sub-daily (i.e., hourly) NP data management, more stringent data integrity tests, and automatic station notification of format and data integrity issues.
    Keywords: Geophysics
    Type: International Laser Ranging Service (ILRS) 1999 Annual Report; 135-136; NASA/TP-2000-209969
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  • 61
    Publication Date: 2011-09-13
    Description: The International Laser Ranging Service (ILRS) is an established Service within Section II , Advanced Space Technology, of the International Association of Geodesy (IAG). The primary objective of the ILRS is to provide a service to support, through Satellite and Lunar Laser Ranging data and related products, geodetic and geophysical research activities as well as International Earth Rotation Service (IERS) products important to the maintenance of an accurate International Terrestrial Reference Frame (ITRF). The service also develops the necessary standards/specifications and encourages international adherence to its conventions.
    Keywords: Geophysics
    Type: International Laser Ranging Service (ILRS) 1999 Annual Report; 217-225; NASA/TP-2000-209969
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  • 62
    facet.materialart.
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    In:  CASI
    Publication Date: 2011-09-13
    Description: The governing board report presents an overview of the Satellite Ranging Service (SLR), the origin and establishment of the International Laser Ranging Service (ILRS), and the organization of the ILRS and how it interfaces with other organizations, the current status and future prospects for the ILRS.
    Keywords: Geophysics
    Type: International Laser Ranging Service (ILRS) 1999 Annual Report; 1-11; NASA/TP-2000-209969
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  • 63
    Publication Date: 2011-08-24
    Description: The spectrum and light curve of the bright X-ray source CG X-1 in the field of the Circinus galaxy are reexamined. Previous analyses have concluded that the source is an accreting black hole of mass 〉 or approx. 50 solar masses although it has been noted that the light curve resembles that of an AM Herculis system. Here we show that the short period and an assumed main-sequence companion constrain the mass of the companion to less than 1 solar mass. Furthermore, a possible eclipse seen during one of the Chandra observations and a subsequent XMM-Newton observation constrain the mass of the compact object to less than 60 solar masses. If such a system lies in the Circinus galaxy, then the accreting object must either radiate anisotropically or strongly violate the Eddington limit. Even if the emission is beamed, then the companion star that intercepts this flux during eclipse will be driven out of thermal equilibrium and evaporate within approx. 10(exp 3) yr. We find that the observations cannot rule out an AM Herculis system in the Milky Way and that such a system can account for the variations seen in the light curve.
    Keywords: Astronomy
    Type: The Astrophysical Journal; Vol. 605; 360-367
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  • 64
    Publication Date: 2004-12-03
    Description: Common rock-forming rhombohedral carbonates - calcite and dolomite - constitute a considerable fraction of terrestrial sediments that may be shocked during hypervelocity impacts, such as during the Cretaceous-Tertiary (K/T) event or at the Haughton structure. The relatively modest temperatures needed to decompose carbonates and to release their CO2 are easily attained during such impacts. However, detailed and quantitative understanding of the CO2 release of carbonates as a function of shock stress is still the subject of controversy, as are a number of other reactions and phase transitions that were suggested for carbonates. The first devolatilization studies of carbonates in the early 1980s suggested that incipient devolatilization of calcite and/or dolomite commences at modest pressures, in the range 〈 10-18 GPa (amounting to 0.03-0.3% CO2 loss), with massive decarbonation (30-40% CO2 loss) occurring at shock pressure of 20 GPa and above. However, most later studies revealed that both calcite and dolomite are unexpectedly stable under shock conditions and no significant outgassing has been observed at pressures as high as 40 GPa for calcite and 60 GPa for dolomite. Despite these uncertainties, the calculations of O'Keefe and Ahrens (and others) serve to illustrate that the K/T bolide liberated sufficient CO2 that a substantial temperature increase of the global atmosphere is possible due to CO2-triggered greenhouse effects. The quantitative understanding of the devolatilization of carbonates as a function of shock stress is obviously critical to refine such calculations. Additional information is contained in the original extended abstract.
    Keywords: Geophysics
    Type: Catastrophic Events and Mass Extinctions: Impacts and Beyond; 202-203; LPI-Contrib-1053
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  • 65
    Publication Date: 2004-12-03
    Description: In the Umbria-Marche region of central Italy, the deep basinal carbonate Scaglia Rossa Formation contains an important sequence of Cretaceous-Tertiary strata including a detailed paleomagnetic record and the distal impactoclastic Cretaceous-Tertiary boundary clay layer. In addition to this significant paleomagnetic and impactoclastic record, the Scaglia Rossa also contains potentially important stratigraphic evidence of relatively long-term oceanic and atmospheric consequences of the Cretaceous-Tertiary bolide catastrophe, which we will describe for the first time herein. Additional information is contained in the original extended abstract.
    Keywords: Geophysics
    Type: Catastrophic Events and Mass Extinctions: Impacts and Beyond; 98-99; LPI-Contrib-1053
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  • 66
    Publication Date: 2004-12-03
    Description: The Permian/Triassic (P/Tr) boundary (251.4 +/- 3 Myr) is marked by the most severe mass extinction in the geologic record. Recently, precise absolute dating has bracketed the marine extinctions and associated carbon-isotope anomaly within less than 1 Myr. We improve this resolution through high-resolution stratigraphy across the P/Tr boundary in the 331-m Gartnerkofel-1 core and nearby Reppwand outcrop section (Carnic Alps, Austria) utilizing FFT and wavelet timeseries analyses of cyclic components in down-hole core logs of density and natural gamma-ray intensity, and carbon-isotopic ratios of bulk samples. The wavelet analysis indicates continuity of deposition across the P/Tr boundary interval, and the timeseries analyses show evidence for persistent cycles in the ratio of approximately 40: 10: 4.7: 2.3 meters, correlated with Milankovitch-band orbital cycles of approximately 412: 100: 40: 20 kyr (eccentricity 1 and 2, obliquity, and precession), and giving a consistent average sedimentation rate of approximately 10 cm/1,000 yr. Milankovitch periods in delta C-13 and density in these shallow-water carbonates were most likely the result of climatically induced oscillations of sea level and climate, coupled with changes in ocean circulation and productivity, that affected sedimentation. Fluctuations in gamma radiation reflect varying input of clay minerals and the presence of shaly interbeds. Throughout the P/Tr boundary interval in the core, the 100,000-year eccentricity cycle seems to be dominant. Weaker obliquity and precession cycles are in line with the location of the Austrian section in the latest Permian, close to the Equator in the western bight of the Tethys, where obliquity and precessional effects on seasonal contrast might be subdued. Using the improved resolution provided by cycle analysis in the GK-1 core, we find that the dramatic change in the faunal record that marks the P/Tr boundary takes place over less than 6m, or less than 60,000 years. In the nearby Reppwand outcrop section, the same faunal changes occurs over only 0.8 m or about 8,000 years, close to the limit of time-resolution induced by bioturbation and reworking in these sediments. The sharp negative global carbon-isotope shift took place within less than or equal to 40,000 yr, and the isotope excursions persisted for approximately 480,000 yr into the Early Triassic. The results indicate that the severe marine faunal event that marks the P/Tr boundary was very sudden, perhaps less than the resolution window in the GK-1 core, and suggest a catastrophic cause. The wavelet-analysis approach to high-resolution cyclostratigraphy can be applied to other P/Tr boundary sections, and when combined with precise absolute dating and magnetostratigraphic methods promises a significant increase in resolution in determining the correlation and tempo of the end-Permian extinctions and related events worldwide.
    Keywords: Geophysics
    Type: Catastrophic Events and Mass Extinctions: Impacts and Beyond; 176; LPI-Contrib-1053
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  • 67
    Publication Date: 2004-12-03
    Description: Health effects from Martian dusts will be a concern for any manned Mars missions. Nuisance dusts plagued the Apollo astronauts, but dusts of more hazardous mineralogy, in habitats occupied by Mars astronauts weakened by a long-duration mission, may be more than a nuisance. Chemical hazards in Martian regolith attributable to S, Cl, Br, Cd, and Pb are known or strongly suspected to be present, but terrestrial studies of the health effects of dusts indicate that accurate determination of mineralogy is a critical factor in evaluating inhalation hazards. Mineral inhalation hazards such as the Group-I carcinogenic zeolite erionite, which is demonstrated to cause mesothelioma, cannot be identified by chemical analysis alone. Studies of palagonite analogs raise the possibility that erionite may occur on Mars. In addition to health effects concerns, environmental mineralogy has significant importance in resource extraction, groundwater use, and sustained agriculture. The high sulfur and chlorine content of Martian regolith will affect all of these uses, but the nature of mineralogic reservoirs for S and Cl will determine their uptake and concentration in extracted groundwater and in agricultural applications of regolith. Wet chemistry experiments planned for the Mars Environmental Compatibility Assessment (MECA) will define some of the consequences of water/soil interaction, but an understanding of the mineralogic basis for water-rock reactions is needed to understand the mechanisms of reaction and to apply the results of a few experiments to larger scales and different conditions.
    Keywords: Geophysics
    Type: Concepts and Approaches for Mars Exploration; Part 2; 300-301; LPI-Contrib-1062-Pt-2
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  • 68
    Publication Date: 2004-12-03
    Description: NASA is preparing to launch the Next Generation Space Telescope (NGST). This telescope will be larger than the Hubble Space Telescope, be launched on an Atlas missile rather than the Space Shuttle, have a segmented primary mirror, and be placed in a higher orbit. All these differences pose significant challenges. This effort addresses the challenge of aligning the segments of the primary mirror during the initial deployment. The segments need to piston values aligned to within one tenth of a wavelength. The present study considers using a neuro-fuzzy model of the Fraunhofer diffraction theory. The intention of the current study was to experimentally verify the algorithm derived earlier. The experimental study was to be performed on the SIBOA (Systematic Image Based Optical Alignment) test bed. Unfortunately the hardware/software for SIBOA was not ready by the end of the study period. We did succeed in capturing several images of two stacked segments with various relative phases. These images can be used to calibrate the algorithm for future implementation. This effort is a continuation of prior work. The basic effort involves developing a closed loop control algorithm to phase a segmented mirror test bed (SIBOA). The control algorithm is based on a neuro-fuzzy model of SIBOA and incorporates nonlinear observers built from observer banks. This effort involves implementing the algorithm on the SIBOA test bed.
    Keywords: Astronomy
    Type: Research Reports: 2001 NASA/ASEE Summer Faculty Fellowship Program; XXXVIII-1 - XXXVIII-5; NASA/CR-2002-211840
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  • 69
    Publication Date: 2004-12-03
    Description: Traditionally, study of the plasmasphere has involved terrestrial observation of local characteristics. Global modeling of the plasmasphere in such an observation regime made use of an ensemble of (sparse) local measurements. Recently, sensors aboard the IMAGE (Imager for Magnetopause-to-Aurora Global Exploration) satellite (in particular, the EUV (Extreme Ultra Violet) Imager) have created the potential for truly global study of the plasmasphere. IMAGE was launched in spring of 2000 in an orbit with apogee altitude 7.2 RE(Earth radii) and perigee altitude 1000 km. IMAGE's EUV sensor allows an external view of the distribution of cold plasma in the plasmasphere to be acquired. EUV is designed to image light emission at 30.4 nanometers, which is the emission wavelength of the He+ ion in the presence of solar radiation. He+ makes up approximately 15-20% of the plasma in the plasmasphere, thus imaging of He+ enables determination of plasma distribution. The EUV instrument provides a 90 deg by 84 deg field of view which is imaged as an equally spaced 150x140 pixel array on a spherical imaging surface. The EUV produces an image approximately every 10 minutes when the sensor is operating. Since EUV images contain line-of-sight integrations of plasma distributions, they do not directly express equatorial plane density (which would enable comparison of observed plasma distributions with predictions from models). Furthermore, the plasma density at any point in three-space is not known. The goal of our work was development of a technique that can enable plasma density to be determined throughout three-space. Our approach to creation of a three-space representation of the plasma distribution involves disintegrating the EUV lines of sight to form a volumetric map of plasma densities.
    Keywords: Astronomy
    Type: Research Reports: 2001 NASA/ASEE Summer Faculty Fellowship Program; XXXVI-1 - XXXVI-5; NASA/CR-2002-211840
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  • 70
    Publication Date: 2004-12-03
    Description: Currently, the establishment of the International Earth Rotation Service (IERS) Special Bureau for Loading (SBL) is in progress as part of the IERS Global Geophysical Fluids Center (GGFC). The main purpose of the SBL is to provide reliable, consistent model predictions of loading signals that have been thoroughly tested and validated. The products will describe at least the surface deformation, gravity signal and geo-center variations due to the various surface loading processes in reference frames relevant for direct comparison with existing geodetic observing techniques. To achieve these goals, major scientific advances are required with respect to the Earth model, the theory and algorithms used to model deformations of the Earth as well as improvements in the observational data related to surface loading.
    Keywords: Geophysics
    Type: International VLBI Service for Geodesy and Astrometry General Meeting Proceeding; 287-291; NASA/CP-2002-210002
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  • 71
    Publication Date: 2004-12-03
    Description: This chapter is concerned with two types of radiometric measurements essential to verify atmospheric correction algorithms and to calibrate vicariously satellite ocean color sensors. The first type is a photometric measurement of the direct solar beam to determine the optical thickness of the atmosphere. The intensity of the solar beam can be measured directly, or obtained indirectly from measurements of diffuse global upper hemispheric irradiance. The second type is a measurement of the solar aureole and sky radiance distribution using a CCD camera, or a scanning radiometer viewing in and perpendicular to the solar principal plane. From the two types of measurements, the optical properties of aerosols, highly variable in space and time, can be derived. Because of the high variability, the aerosol properties should be known at the time of satellite overpass. Atmospheric optics measurements, however, are not easy to perform at sea, from a ship or any platform. This complicates the measurement protocols and data analysis. Some instrumentation cannot be deployed at sea, and is limited to island and coastal sites. In the following, measurement protocols are described for radiometers commonly used to measure direct atmospheric transmittance and sky radiance, namely standard sun photometers, fast-rotating shadow-band radiometers, automated sky scanning systems, and CCD cameras. Methods and procedures to analyze and quality control the data are discussed, as well as proper measurement strategies for evaluation of atmospheric correction algorithms and satellite-derived ocean color.
    Keywords: Geophysics
    Type: In Situ Aerosol Optical Thinkness Collected by the SIMBIOS Program (1997-2000): Protocols, and and Data QC and Analysis; 26-42; NASA/TM-2001-209982
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  • 72
    Publication Date: 2004-12-03
    Description: The goal of this project is to identify the process responsible for the formation of geomorphic features in the Black Point Drive area of Merritt Island National Wildlife Refuge/Kennedy Space Center (MINWR/KSC), northwest Cape Canaveral. This study confirms the principal landscape components (geomorphology) of Black Point Drive reflect interaction between surficial sediments deposited in association with late-Quaternary sea-level highstands and the chemical evolution of late-Cenozoic subsurface limestone formations. The Black Point Drive landscape consists of an undulatory mesic terrain which dips westward into myriad circular and channel-like depression marshes and lakes. This geomorphic gradient may reflect: (1) spatial distinctions in the elevation, character or age of buried (pre-Miocene) limestone formations, (2) dissolution history of late-Quaternary coquina and/or (3) thickness of unconsolidated surface sediment. More detailed evaluation of subsurface data will be necessary before this uncertainty can be resolved.
    Keywords: Geophysics
    Type: 2000 Research Reports: NASA/ASEE Summer Faculty Fellowship Program; 157-166; NASA/CR-2001-210260
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  • 73
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2009-05-17
    Description: The Far Ultraviolet Spectroscopic Explorer (FUSE) is studying a wide range of astronomical problems in the 905-1187 Angstrom wavelength region through the use of high resolution spectroscopy. The FUSE bandpass forms a nearly optimal complement to the spectral coverage provided by the Hubble Space Telescope (HST), which extends down to approximately 1170 Angstroms. The photoionization threshold of atomic hydrogen (911 Angstroms) sets a natural short-wavelength limit for the FUV. FUSE was launched in June 1999 from Cape Canaveral, Florida, on a Delta II rocket into a 768 km circular orbit. Scientific observations started later that year. This spectral region is extremely rich in spectral diagnostics of astrophysical gases over a wide range of temperatures (100 K to over 10 million K). Important strong spectral lines in this wavelength range include those of neutral hydrogen, deuterium, nitrogen, oxygen, and argon (H I, D I, N I, O I, and Ar I), molecular hydrogen (H2), five-times ionized oxygen (O VI), and several ionization states of sulfur (S III - S VI). These elements are essential for understanding the origin and evolution of the chemical elements, the formation of stars and our Solar System, and the structure of galaxies, including our Milky Way. FUSE is one of NASA's Explorer missions and a cooperative project of NASA and the space agencies of Canada and France. These missions are smaller, more scientifically focused missions than the larger observatories, like Hubble and Chandra. FUSE was designed, built and operated for NASA by the Department of Physics and Astronomy at Johns Hopkins University. Hundreds of astronomers world-wide are using FUSE for a wide range of scientific research. Some of the important scientific discoveries from the first two years of the mission are described.
    Keywords: Astronomy
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  • 74
    Publication Date: 2009-11-16
    Description: We present results of new ASCA observations of the low-luminosity AGN (LLAGN) NGC 4579 obtained in 1998 December 18 and 28, and we report on detection of variability of an iron K emission line. The X-ray luminosities in the 2-10 keV band for the two observations are nearly identical, L(sub X) approximately = 2 x 10(exp 4l) ergs/s, but they are approximately 35% larger than that measured in 1995 July by Terashima et al. (1998). An Fe K emission line is detected at 6.39 +/- 0.09 keV (source rest frame) which is lower than the line energy 6.73(sup +0.13, sub -0.12) keV in the 1995 observation. If we fit the Fe lines with a blend of two Gaussians centered at 6.4 keV and 6.73 KeV, the intensity of the 6.7 keV line decreased, while the intensity of the 6.4 keV line increased, within an interval of 3.5 years. This variability rules out thermal plasmas in the host galaxy as the origin of the ionized Fe line in this LLAGN. The detection and variability of the 6.4 keV line suggest that an optically thick standard accretion disk is present and subtends a large solid angle viewed from the nucleus at the Eddington ratio of L(sub Bol)/L(sub Eddington) approximately 2 x 10(exp -3) (Ho 1999). A broad disk-line profile is not clearly seen and the structure of the innermost part of accretion disk remains unclear.
    Keywords: Astronomy
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  • 75
    Publication Date: 2009-05-04
    Description: Apart from the "shaking" near the epicenter that is the earthquake, a seismic event creates a permanent field of dislocation in the entire Earth. This redistribution of mass changes (slightly) the Earth's inertia tensor; and the Earth's rotation will change in accordance with the conservation of angular momentum. Similar to this seismic excitation of Earth rotation variations, the same mass redistribution causes (slight) changes in the Earth's gravitational field expressible in terms of changes in the Stokes coefficients of its harmonic expansion. In this paper, we give a historical background of the subject and discuss the related physics; we then compute the geodynamic effects caused by earthquakes based on normal-mode summation scheme. The effects are computed using the centroid moment tensor (CMT) solutions for 15,814 major earthquakes from Jan., 1977, through Feb., 1999, as provided in the Harvard CMT catalog. The computational results further strengthens these findings and conclusions: (i) the strong tendency for earthquakes to make the Earth rounder and more compact (however slightly) continues; (ii) so does the trend in the seismic "nudging" of the rotation pole toward the general direction of approx. 140 E, roughly opposite to that of the observed polar drift, but two orders of magnitude smaller in drift speed.
    Keywords: Geophysics
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  • 76
    Publication Date: 2004-10-05
    Description: The bright variable star theta(sup 2) Tau was monitored with the star camera on the Wide-Field Infrared Explorer satellite. Twelve independent frequencies were detected down to the 0.5 mmag amplitude level. Their reality was investigated by searching for them using two different algorithms and by some internal checks: both procedures strengthened our confidence in the results. All the frequencies are in the range 10.8-14.6 cd(exp -1). The histogram of the frequency spacings shows that 81% are below 1.8 d; rotation may thus play a role in the mode excitation. The fundamental radial mode is not observed, although it is expected to occur in a region where the noise level is very low (55 mu mag). The rms residual is about two times lower than that usually obtained from successful groundbased multisite campaigns. The comparison of the results of previous campaigns with the new ones establishes the amplitude variability of some modes.
    Keywords: Astronomy
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  • 77
    Publication Date: 2004-12-03
    Description: Ground-based differential photometry is limited to a precision of order 10(exp -3) because of atmospheric effects. A space-based photometer should be limited only by the inherent instrument precision and shot noise. Laboratory tests have shown that a precision of order 10-5 is achievable with commercially available charged coupled devices (CCDs). We have proposed to take this one step further by performing measurements at a telescope using a Wollaston prism as a beam splitter First-order atmospheric effects (e.g., extinction) will appear to be identical in the two images of each star formed by the prism and will be removed in the data analysis. This arrangement can determine the precision that is achievable under the influence of second-order atmospheric effects (e.g., variable point-spread function (PSF) from seeing). These telescopic observations will thus provide a lower limit to the precision that can be realized by a space-based differential photometer.
    Keywords: Astronomy
    Type: Third Workshop on Photometry; 95-102; NASA/CP-2000-209614
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  • 78
    Publication Date: 2004-12-03
    Description: Analysis of the images produced by the first version (V1) of the Vulcan photometer indicated that two major sources of noise were sky brightness and image motion. To reduce the effect of the sky brightness, a second version (V2) with a longer focal length and a larger format detector was developed and tested. The first version consisted of 15-centimeter (cm) focal length, F/1.5 Aerojet Delft reconnaissance lens, and a 2048 x 2048 format front-illuminated charged coupled device (CCD) with 9 microns micropixels (Mpixels). The second version used a 30-cm focal length, F/2.5 Kodak AeroEktar lens, and a 4096 x 4096 format CCD with 9 micro pixels. Both have a 49-square-degree field of view (FOV) but the area of the sky subtended by each pixel in the V2 version is one-fourth that of the V1 version. This modification substantially reduces the shot noise due to the sky background and allows fainter stars to be monitored for planetary transits. To remove the data gap and consequent signal-level change caused by flipping the photometer around the declination axis and to reduce image movement on the detector, several other modifications were incorporated. These include modifying the mount and stiffening the photometer and autoguider structures to reduce flexure. This paper compares the performance characteristics of each photometer and discusses tests to identify sources of systematic noise.
    Keywords: Astronomy
    Type: Third Workshop on Photometry; 63-70; NASA/CP-2000-209614
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  • 79
    Publication Date: 2004-12-03
    Description: Experiments have shown that a low-density jet injected into a high-density surrounding medium undergoes periodic oscillations in the near field. Although the flow oscillations in these jets at Richardson numbers about unity are attributed to the buoyancy, the direct physical evidence has not been acquired in the experiments. If the instability were indeed caused by buoyancy, the near-field flow structure would undergo drastic changes upon removal of gravity in the microgravity environment. The present study was conducted to investigate this effect by simulating microgravity environment in the 2.2-second drop tower at the NASA Glenn Research Center. The non-intrusive, rainbow schlieren deflectometry technique was used for quantitative measurements of helium concentrations in buoyant and non-buoyant jets. Results in a steady jet show that the radial growth of the jet shear layer in Earth gravity is hindered by the buoyant acceleration. The jet in microgravity was 30 to 70 percent wider than that in Earth gravity. The microgravity jet showed typical growth of a constant density jet shear layer. In case of a self-excited helium jet in Earth gravity, the flow oscillations continued as the jet flow adjusted to microgravity conditions in the drop tower. The flow oscillations were however not present at the end of the drop when steady microgravity conditions were reached.
    Keywords: Geophysics
    Type: Sixth Microgravity Fluid Physics and Transport Phenomena Conference: Exposition Topical Areas 1-6; Volume 2; 475-486; NASA/CP-2002-211212/VOL2
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  • 80
    Publication Date: 2004-12-03
    Description: In the late 1980s there was a flurry of activities involving the newly discovered high Tc superconductors in the development of new devices such as more efficient current transmission, transformers, generators, and motors. One such developmental project by Podkletnov in 1992 noted some small, anomalous gravitational behaviors. A following unpublished paper by Podkletnov 1995 provided data with larger effects using a larger (approx. 25 cm) superconducting disk. Unfortunately this disk was extremely fragile and was broken beyond repair. To date, these experiments have not been successfully repeated because of the difficulties of producing stable, durable (and fired) superconducting disks. This problem with firing these disks has been solved by Li. What remains is to install the disk in "motor", at superconducting temperatures in the presence of appropriately tailored magnetic fields.
    Keywords: Geophysics
    Type: Research Reports: 2001 NASA/ASEE Summer Faculty Fellowship Program; XLVIII-1 - XLVIII-6; NASA/CR-2002-211840
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  • 81
    Publication Date: 2004-12-03
    Description: Following the success of the VLBI Space Observatory Program (VSOP), a next generation space VLBI mission (VSOP-2) is currently being planned. We expect the data rate of more than 1 Gbps to get more sensitivity. Here we will present: (1) How to sample the data (on board), including the radiation test results which show we can have the 10 Gbps sampler LSI which can use in space; (2) Possibility of the bit rate more than 1 Gbps to downlink the VLBI data. We studied the link budget for the wide band data transmission, and discussed the various ideas which can get more than 1 Gbps; and (3) What kind of VLBI tracking station and recording system will be expected for the VSOP-2 mission? We will present the idea of using normal radio telescopes as a tracking station, and also review the possibility of recording and processing at the tracking stations and correlators.
    Keywords: Geophysics
    Type: International VLBI Service for Geodesy and Astrometry General Meeting Proceeding; 175-178; NASA/CP-2002-210002
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  • 82
    Publication Date: 2004-12-03
    Description: This report summarizes the technical parameters and the technical staff of the Very Long Base Interferometry (VLBI) system at the fundamental station Goddard Geophysical and Astronomical Observatory (GGAO). It also gives an overview about the VLBI activities during the previous year. The outlook lists the outstanding tasks to improve the performance of GGAO.
    Keywords: Astronomy
    Type: International VLBI Service for Geodesy and Astrometry; 81-82; NASA/TP-2001-209979
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  • 83
    Publication Date: 2004-12-03
    Description: Two field studies in the Mojave Desert, California, shed light on processes of ventifact formation. The field sites are located on a ridge at Little Cowhole Mountain, which lies approximately 12 km south of Baker, and on an unnamed ridge situated along the northern boundary of the Mojave River Sink (Rasor Road site). The rocks at Little Cowhole Mountain are a blue-grey marble/dolomite, whereas those at Rasor Road are Miocene volcanic rocks (basalt). At both sites the abrasive agent is a fine-grained aeolian sand which was probably derived largely from the Mojave River. There are minimal modem inputs of sand to either site: abrasion occurs as a result of unique climatic and topographic conditions which allow pre-existing sand to be recycled from one aspect of the ridge to the other. Climatic conditions are well suited for ventifact formation. Owing, to the dry climate (marked by low average relative humidity, infrequent dew, and low annual rainfall), rates of chemical weathering are low. Where resurfacing of the rocks by sand abrasion proceeds at a rate greater than weathering, the ventifacts are considered "active." Active ventifacts are found atop and straddling the ridge crests, in the zone of maximum wind velocity and sediment supply. Inactive ventifacts occur where modem weathering Processes exceed abrasion rates; principally on the basal two-thirds of the hillslope, where wind velocity and sediment supply are lower. At intermediate locations between the slope base and crest, ventifacts are either active or inactive, depending on local conditions. The presence of relict ventifacts at the study sites, as well as elsewhere in the eastern Mojave Desert, suggests that the conditions for venti fact formation must have been more intense and extensive in the past. Together, the studies illustrate that the processes that interact to form ventifacts are highly complex, and must be studied at many scales. Small-scale effects, such as local topography, plant cover, or even the spatial distribution of boulders, strongly influence the formation of each individual ventifact. Mesoscale effects (hillslope form, total availability of sediment, seasonality of winds, etc.) determine the distribution of overall erosional energy and the location of active and relict forms.
    Keywords: Geophysics
    Type: Field Trip and Workshop on the Martian Highlands and Mojave Desert Analogs; 41-42; LPI-Contrib-1101
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  • 84
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2004-12-03
    Description: The AAC at JCET/GSFC has been slowly coming on line with the activities we had originally proposed to ILRS. The delay is primarily the result of only partial funding of these activities by our sponsors. Despite these problems we have completed a substantial amount of the analysis that we intended to contribute to ILRS this year. We have participated in the IERS/ITRF Pilot Project for TRF definition and the ILRS Pilot Project for site and EOP SINEX file submission. This past year we submitted a preliminary solution to IERS and in 2000 we intend to contribute an iterated version for the new major TRF realization, ITRF2000.
    Keywords: Geophysics
    Type: International Laser Ranging Service (ILRS) 1999 Annual Report; 189-191; NASA/TP-2000-209969
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  • 85
    Publication Date: 2011-08-23
    Description: The 89 s X-ray pulsar XTE J1906+09 was discovered during Rossi X-Ray Timing Explorer (RXTE) observations of SGR 1900+14 in 1996. Because of monitoring campaigns of SGR 1900+14, XTE J1906+09 was also monitored regularly in 1996 September, 1998 May-June, 1998 August-1999 July, and 2000 March-2001 January. A search for pulsations resulted in detections of only the two previously reported outbursts in 1996 September and 1998 August-September. Pulsed flux upper limits for the rest of the observations show that XTE J1906+09 is a transient X-ray pulsar and likely has a Be star companion. The RXTE all-sky monitor did not reveal XTE J1906+09. Pulse-timing analysis of the second outburst discovered a sinusoidal signature in the pulse frequencies that is likely produced by an orbital periastron passage. Fits to pulse phases using an orbital model and quadratic phase model have chi(exp 2) minima at orbital periods of 26-30 days for fixed mass functions of 5, 10, 15, and 20 solar masses. The pulse shape showed energy- and intensity-dependent variations. Pulse-phase spectroscopy quantified the energy-dependent variations. The phase-averaged spectrum used the pulse minimum spectrum as the background spectrum to eliminate effects from SGR 1900+14 and the Galactic ridge and was well fitted by an absorbed power law with a high-energy cutoff with column density N(sub H) = 6 +/- 1 x 10(exp 22)/sq cm, a photon index of 1.01 +/- 0.08, cutoff energy E(sub cut) = 11 +/- 1 keV, and e-folding energy E(sub fold) = 19 +/- 4 keV. Estimated 2-10 keV peak fluxes, corrected for contributions from the Galactic ridge and SGR 1900+14, are 6 x l0(exp -12) and 1.1 x 10(exp -10) ergs/sq cm/s for the 1996 and 1998 outbursts, respectively. XTE J1906+09 may be part of an unusual class of Be/X-ray binaries that do not lie on the general spin period versus orbital period correlation with the majority of Be/X-ray binaries.
    Keywords: Astronomy
    Type: The Astrophysical Journal; Volume 565; 1150-1160
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  • 86
    Publication Date: 2011-08-23
    Description: We present X-ray emission-line equivalent width images of the bright Galactic supernova remnant Cassiopeia A for the elements Si, S, Ar, Ca, and Fe using a 50,000 s observation with the Advanced CCD Imaging Spectrometer on the Chandra X-Ray Observatory. The images essentially map the bulk of detectable ejecta of these elements over a wide range of surface brightnesses and show morphologies distinctly different from that of the broadband X-ray emission and the 4-6 keV continuum emission. The Si, S, Ar, and Ca maps, while different in turn from those of Fe, are similar to the distribution of fast optical ejecta knots in that they clearly delineate the X-ray counterpart of the northeast optical jet. Low surface brightness regions just outside the bright shell in the north and west are also shown to have strong line emission. The strong Fe emission is exterior to that of other elements in the east, as previously noted, but is generally coincident elsewhere. The projected interior has relatively little emission traced by high line equivalent widths.
    Keywords: Astronomy
    Type: The Astrophysical Journal; Volume 537; L119-L122
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  • 87
    Publication Date: 2011-08-23
    Description: We report the discovery in archival Rossi X-Ray Timing Explorer data of a approx. 40 Hz quasi-periodic oscillation QPO) in the hard X-ray flux from the Galactic microquasar GRS 1915+105. The QPO is detected only in the hard X-ray band above approx. 13 keV and was discovered in observations in which the previously known 67 Hz QPO is present. The 40 Hz QPO has a typical rms amplitude of approx. 2% in the 13-27 keV band and a width of approx. 5.5 Hz (FWHM). We show that the 67 and 40 Hz QPOs are detected in the same observations in 1997 July and November. However, the QPO is not detected in observations from 1996 April, May, and June in which the 67 Hz QPO was first discovered. The frequency of the 67 Hz QPO is significantly higher in the 1997 observations by about 5% compared with the 1996 data. The identification of the 40 Hz QPO makes GRS 1915 + 105 the second black hole binary to show a pair of simultaneous high-frequency QPOs (the other being GRO J1655-40). The similarities between the properties of the 67 Hz QPO in GRS 1915+105 and the recently discovered 450 Hz QPO in GRO J1655-40 suggest that the pairs of frequencies in these systems may be produced by the same physical mechanism, with the frequency differences between the two being likely due to different black hole masses in the two systems. We discuss the implications of our result for the mass and spin of GRS 1915+105 as well as for models of X-ray variability in black holes and neutron stars.
    Keywords: Astronomy
    Type: Astronomical Journal; Volume 554; L169-L172
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  • 88
    Publication Date: 2011-08-23
    Description: We map the average line-of-sight velocities of the X-ray-emitting mass in the supernova remnant Cassiopeia A using measurements of the centroid of the Si-Healpha blend with the Advanced CCD Imaging Spectrometer on the Chandra X-Ray Observatory. This 4 inch scale map confirms the broad trends noted in previous studies, namely, that the line-of-sight velocity scale is roughly 2000-3000 kilometers per second with relatively more blueshifted material in the southeastern region of the remnant than in the northwest; new details are that the northwestern region consists of two arcs, with the southernmost one representing the most redshifted X-ray-emitting material in Cas A. These results are consistent with contemporaneous results from XMM-Newton. The X-ray patterns resemble the complex velocity patterns measured at optical wavelengths for much denser ejecta, and they support the growing body of evidence that the explosion and subsequent evolution of Cas A were highly asymmetrical.
    Keywords: Astronomy
    Type: The American Astrophysical Society; Volume 560; L175-L179
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  • 89
    Publication Date: 2011-08-23
    Description: We investigate the effect of pulsar polar cap (PC) heating produced by positrons returning from the upper pair formation front. Our calculations are based on a self-consistent treatment of the pair dynamics and the effect of electric field screening by the returning positrons. We calculate the resultant X-ray luminosities and discuss the dependence of the PC heating efficiencies on pulsar parameters, such as characteristic spin-down age, spin period, and surface magnetic field strength. In this study we concentrate on the regime where the pairs are produced in a magnetic field by curvature photons emitted by accelerating electrons. Our theoretical results are not in conflict with the available observational x-ray data and suggest that the effect of PC heating should significantly contribute to the thermal x-ray fluxes from middle-aged and old pulsars. The implications for current and future x-ray observations of pulsars are briefly outlined.
    Keywords: Astronomy
    Type: The Astrophysical Journal; Volume 556; 987-1001
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  • 90
    Publication Date: 2011-08-23
    Description: We present a 2-10 keV ASCA (Advanced Satellite for Cosmology and Astrophysics) observation of the field around the soft gamma repeater SGR 1627-41. A quiescent X-ray source, whose position is consistent both with that of a recently discovered BeppoSAX X-ray source and with the Interplanetary Network localization for this soft gamma repeater, was detected in this observation. In 2-10 keV X-rays, the spectrum of the X-ray source may be fit equally well by a power-law, blackbody, or bremsstrahlung function, with unabsorbed flux equal to approximately 5 x 10(exp -12) ergs cm(exp -2) s(exp -1). We do not confirm a continuation of a fading trend in the flux, and we find no evidence for periodicity, both of which were noted in the earlier BeppoSAX observations.
    Keywords: Astronomy
    Type: Astrophysical Journal; Volume 528; L21-L23
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  • 91
    facet.materialart.
    Unknown
    In:  Other Sources
    Publication Date: 2011-08-23
    Description: With the observation of low-energy radiation coming from the site of gamma-ray bursts in the hours to weeks after the initial gamma ray burst, it appears that astronomers have discovered a cosmological imprint made by the burster on its surroundings. This paper discusses the phenomenon of postburst emission in Burst and Transient Source Experiment (BATSE) gamma-ray bursts at energies usually associated with prompt emission. After summing up the background-subtracted signals from hundreds of bursts, it is found that tails out to hundreds of seconds after the trigger could be a common feature of events of a duration greater than 2 seconds, and perhaps of the shorter bursts at a lower and shorter-lived level. The tail component may be softer and seems independent of the duration (within the long-GRB sample) and brightness of the prompt burst emission. Some individual bursts have visible tails at gamma-ray energies, and the spectrum in a few cases differs from that of the prompt emission. For one of these bursts, GRB 991216, afterglow at lower energies was detected, which raised the possibility of seeing afterglow observations over large energy ranges using the next generation of GRB detectors in addition to sensitive space- or ground-based telescopes.
    Keywords: Astronomy
    Type: The Astrophysical Journal; Volume 567; 1028-1036
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  • 92
    Publication Date: 2011-08-23
    Description: We observe a slow-onset quiet-region filament eruption with the Extreme Ultraviolet Imaging Telescope (EIT) on the Solar Heliospheric Observatory (SOHO) and the Soft X-ray Telescope (SXT) on Yohkoh. This event occurred on 1999 April 18 and was likely the origin of a coronal mass ejection detected by SOHO at 08:30 UT on that day. In the EIT observation, one-half of the filament shows two stages of evolution: stage 1 is a slow, roughly constant upward movement at approximately 1 km/s lasting approximately 0.5 hr, and stage 2 is a rapid upward eruption at approximately 16 km/s occurring just before the filament disappears into interplanetary space. The other half of the filament shows little motion along the line of sight during the time of stage 1 but erupts along with the rest of the filament during stage 2. There is no obvious emission from the filament in the SXT observation until stage 2; at that time, an arcade of EUV and soft X-ray loops forms first at the central location of the filament and then expands outward along the length of the filament channel. A plot of EUV intensity versus time of the central portion of the filament (where the postflare loops initially form) shows a flat profile during stage 1 and a rapid upturn after the start of stage 2. This light curve is delayed from what would be expected if 'tether-cutting' reconnection in the core of the erupting region were responsible for the initiation of the eruption. Rather, these observations suggest that a loss of stability of the magnetic field holding the filament initiates the eruption, with reconnection in the core region occurring only as a by-product.
    Keywords: Astronomy
    Type: Astrophysical Journal; Volume 561; L219-L222
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  • 93
    Publication Date: 2011-08-23
    Description: We describe an optical method based on laser-induced fluorescence for obtaining instantaneous measurements of density along a line in low-density air seeded with I2. The Cordes bands of I2 (D(sup 1)sigma(sup +, sub u)) left arrow X(sup 1)sigma(sup +, sub g)) are excited with a tunable ArF excimer laser. air densities in the range (0.1-6.5) x 10(exp 17) cm(exp -3) are measured over 295-583 K using the density-dependent emission ratio of two emission bands of I2; the 340 nm bands and the diffuse-structured McLennan bands near 320 nm.
    Keywords: Geophysics
    Type: Measurement Science and Technology (ISSN 0957-0233); Volume 11; 459-466
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  • 94
    Publication Date: 2011-08-23
    Description: The magnetic flux content of the Jovian magnetosphere is set by the internal dynamo, but those magnetic field lines are constantly being loaded by heavy ions at the orbit of lo and dragged inexorably outward by the centrifugal force. Vasyliunas has proposed a steady state reconnecting magnetospheric model that sheds plasma islands of zero net magnetic flux and returns nearly empty flux tubes to the inner magnetosphere. The Galileo observations indicate that beyond 40 Rj the current sheet begins to tear and beyond 50 Rj on the nightside explosively reconnects as the tearing site reaches the low density lobe region above and below the current sheet. Small events occur irregularly but on average about every 4 hours and large events about once a day. The magnetic flux reconnected in such events amounts up to about 70,000 Webers/sec and is sufficient to return the outwardly convected magnetic flux to the inner magnetosphere. Since this process releases plasmoids into the jovian tail, as do terrestrial substorms; since this process involves explosive reconnection across the current sheet on the nightside of the planet, as do terrestrial substorms; and since the process is a key in closing the circulation pattern of the magnetic and plasma flux, as it is in terrestrial substorms; we refer to these events as jovian substorms.
    Keywords: Astronomy
    Type: Advanced Space Research (ISSN 0273-1177); Volume 26; No. 10; 1499-1504
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  • 95
    Publication Date: 2011-08-24
    Description: No abstract available
    Keywords: Astronomy
    Type: Stellar Astrophysics, Proceedings of the Pacific; 267
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  • 96
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2013-08-31
    Description: The Space Interferometry Mission (SIM) is a space-based 10 m baseline Michelson interferometer. Planned for launch in 2005 aboard a Delta III launch vehicle, or equivalent, its primary objective is to measure the positions of stars and other celestial objects with an unprecedented accuracy of 4 micro arc seconds. With such an instrument, tremendous advancement can be expected in our understanding of stellar and galactic dynamics. Using triangulation from opposite sides of the orbit around the sun (i.e. by using parallax) one can measure the distance to any observable object in our galaxy. By directly measuring the orbital wobble of nearby stars, the mass and orbit of planets can be determined over a wide range of parameters. The distribution of velocity within nearby galaxies will be measurable. Observations of these and other objects will improve the calibration of distance estimators by more than an order of magnitude. This will permit a much better determination of the Hubble Constant as well as improving our overall understanding of the evolution of the universe. SIM has undergone several transformations, especially over the past year and a half since the start of Phase A. During this phase of a project, it is desirable to perform system-level trade studies, so the substantial evolution of the design that has occurred is quite appropriate. Part of the trade-off process has addressed two major underlying architectures: SIM Classic; and Son of SIM. The difference between these two architectures is related to the overall arrangement of the optical elements and the associated metrology system. Several different configurations have been developed for each architecture. Each configuration is the result of design choices that are influenced by many competing considerations. Some of the more important aspects will be discussed. The Space Interferometry Mission has some extremely challenging goals: millikelvin thermal stability, nanometer stabilization of optics, picometer measurement of wavefront, and others. In order to meet these goals, a significant amount of technological development is required. Although there has been a program operating for about a decade developing technologies specifically to address the challenges of space-based interferometry, there still remains a tremendous effort to achieve the incredible accuracy required of SIM. The projected viability of some of these areas has influenced design choices during the evolution of the many configurations that have been developed. For instance, the perceived complexity of the IR laser metrology system used to measure and control the positions of key optical elements was the strongest discriminator between the two architectures, and led to a decision to select SOS rather than Classic in early 1998. More recently, an appreciation of the sensitivity to beam-walk within the SOS architecture is forcing a reconsideration of that decision. At the time of submission of this abstract, there is some hope that a full-aperture metrology system may alleviate this issue. In addition to describing the current configuration of SIM, the influence of a few selected areas on the evolution of the configuration will be discussed.
    Keywords: Astronomy
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  • 97
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2013-08-31
    Description: The Trans-Pacific Astronomy Experiment is Phase 2 of the Trans-Pacific High Data Rate Satcom Experiments following the Trans-Pacific High Definition Video Experiment. It is a part of the Global Information Infrastructure-Global Interoperability for Broadband Networks Project (GII-GIBN). Provides global information infrastructure involving broadband satellites and terrestrial networks and access to information by anyone, anywhere, at any time. Collaboration of government, industry, and academic organizations demonstrate the use of broadband satellite links in a global information infrastructure with emphasis on astronomical observations, collaborative discussions and distance learning.
    Keywords: Astronomy
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  • 98
    Publication Date: 2013-08-29
    Description: This study evaluates the spatial distributions and seasonal cycles in upper tropospheric ozone (pressure range 200-500 hPa) from low to high latitudes (60S to 60N) derived from the satellite retrieval method called "Cloud Slicing." Cloud Slicing is a unique technique for determining ozone profile information in the troposphere by combining co-located measurements of cloud-top, pressure and above-cloud column ozone. For upper tropospheric ozone, co-located measurements of Nimbus 7 Total Ozone Mapping Spectrometer (TOMS) above-cloud column ozone, and Nimbus 7 Temperature Humidity Infrared Radiometer (THIR) cloud-top pressure during 1979-1984 were incorporated. In the tropics, upper tropospheric ozone shows year-round enhancement in the Atlantic region and evidence of a possible semiannual variability. Upper tropospheric ozone outside the tropics shows greatest abundance in winter and spring seasons in both hemispheres with largest seasonal and largest amounts in the NH. These characteristics are similar to lower stratospheric ozone. Comparisons of upper tropospheric column ozone with both stratospheric ozone and a proxy of lower stratospheric air mass (i.e., tropopause pressure) from National Centers for Environmental Prediction (NCEP) suggest that stratosphere-troposphere exchange (STE) may be a significant source for the seasonal variability of upper tropospheric ozone almost everywhere between 60S and 60N except in low latitudes around 10S to 25N where other sources (e.g., tropospheric transport, biomass burning, aerosol effects, lightning, etc.) may have a greater role.
    Keywords: Geophysics
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  • 99
    Publication Date: 2013-08-29
    Description: The high precision gravity measurements to be made by recently launched (and recently approved) satellites place new demands on models of Earth, atmospheric, and oceanic tides. The latter is the most problematic. The ocean tides induce variations in the Earth's geoid by amounts that far exceed the new satellite sensitivities, and tidal models must be used to correct for this. Two methods are used here to determine the standard errors in current ocean tide models. At long wavelengths these errors exceed the sensitivity of the GRACE mission. Tidal errors will not prevent the new satellite missions from improving our knowledge of the geopotential by orders of magnitude, but the errors may well contaminate GRACE estimates of temporal variations in gravity. Solar tides are especially problematic because of their long alias periods. The satellite data may be used to improve tidal models once a sufficiently long time series is obtained. Improvements in the long-wavelength components of lunar tides are especially promising.
    Keywords: Geophysics
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  • 100
    Publication Date: 2013-08-29
    Description: An evaluation is presented of the performance in the northern winter 1999/2000 of the GEOS-3 troposphere-stratosphere data assimilation system (DAS). The impacts of the two main input data types are assessed: upper-air soundings (sondes) provide wind and temperature information and satellite-based (Tiros Operational Vertical Sounders: TOVS) give estimates of the thermal structure. It is shown that in the low stratosphere (300-70hPa) the analyses are generally slightly warmer than the sonde data, but colder than the TOVS data; this relationship reverses between 70 and 10 hPa. There are geographical biases, related to the spatial and temporal coverage of the observation types and to the statistical weights assigned to them in the DAS. Forecasts show a tendency to reduce zonal asymmetries in the atmospheric flow and to suppress stratospheric temperature minima. In the DAS, the analysis increments compensate for this, but it leads to important biases in the multi-day forecasts. The analysis increments are as large as the diabatic forcing in the lower polar stratosphere, indicating a substantial model bias. The results provide important insights into the roles of different data types and the circulation model in producing accurate analyses for studies of polar chemistry and physical processes.
    Keywords: Geophysics
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