7,622 research outputs found

    A bibliography of planetary geology principal investigators and their associates, 1979 - 1980

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    This bibliography cites 698 reports and articles published from May 1979 through May 1980 by principal investigators and associates who received support from NASA's Office of Space Science, as part of the Planetary Geology program. Entries are arranged in the following categories: (1) general interest; (2) solar system, asteroids, comets, and satellites; (3) structure, tectonics, and stratigraphy; (4) regolith and volatiles; (5) volcanism; (6) impact craters; (7) Eolian glacial An author index is provided. The bibliography serves as a companion document to NASA TM 81776, "Reports of Planetary Geology Programs, 1979-1980"

    Cratering history of Miranda

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    The surface of the southern hemisphere of Miranda imaged by Voyager 2 is divisible into two general types of terrain: cratered terrain, characterized by numerous craters and undulating intercrater plains; and basins, circular to rectangular areas of complex morphology having large-scale albedo markings. To determine the relative ages of the terrains and the length of geological activity, crater-frequency data were compiled for various parts of the cratered terrain and basins. Crater-frequency data indicate that the cratered terrain is the oldest terrain on Miranda and that it was locally resurfaced

    Geology and cratering history of Ariel

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    The surface of Ariel imaged by Voyager 2 can be divided into several types of terrain on the basis of morphology: cratered terrain, subdued terrain, ridged terrain, and plains. Crater statistics were compiled for each of the terrain types. Despite differing morphology, the various terrains on Ariel do not exhibit large variations in crater frequency. None of the observed surfaces on Ariel record the period of accretion. It seems that conditions appropriate for resurfacing could have occurred during the early history of Ariel

    Applications of calculus of variations to trajectory analysis Final report

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    Applying calculus of variations to multistage rocket trajectory analysi

    Geochemistry and metallogeny of Neoproterozoic pyrite in oxic and anoxic sediments

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    The Neoproterozoic Dalradian Supergroup contains widespread diagenetic sulphides present as pyrite. The sulphides occur in both carbonaceous shales and glacial diamictites, that were deposited in relatively reducing and oxidising conditions respectively. The trace element compositions of the pyrite, and consequently the whole rock compositions, contrast between the two lithologies. The highest concentrations of selenium, tellurium and gold are all found in diamictite-hosted pyrite. The data suggest that increased mobility of these elements in oxidising conditions led to greater uptake when pyrite was precipitated. As one model for the formation of orogenic gold ore deposits assumes a sulphide-rich protolith, pyrite ultimately formed during relatively oxidising conditions could make a contribution, including the widespread pyrite precipitated during the Neoproterozoic ‘Snowball Earth’ glaciations

    A black shale protolith for gold-tellurium mineralisation in the Dalradian Supergroup (Neoproterozoic) of Britain and Ireland

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    The Dalradian Supergroup of Britain and Ireland is mineralised by gold-tellurium vein deposits. The host succession includes carbonaceous, pyritic shales (pelites) which were a source of trace elements, including gold and tellurium. LA-ICP-MS mapping of pyrite crystals shows that late stages are enriched in gold, tellurium and lead, representing concentration of these elements during metamorphism and related hydrothermal activity. The sulphur isotope composition of the pyrite varies with stratigraphic position, reflecting an origin for the pyrite in the depositional environment through microbial sulphate reduction. Where pyrite was converted to pyrrhotite, trace element contents are much lower, indicating element liberation during metamorphism. These observations are consistent with a model of black shale protoliths for orogenic gold deposits

    Antiseptic technology: access, affordability, and acceptance.

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    Factors other than antimicrobial activity of soaps and antiseptic agents used for hand hygiene by health personnel play a role in compliance with recommendations. Hand hygiene products differ considerably in acceptance by hospital personnel. If switching from a nonmedicated soap to an antiseptic agent or increased use of an existing antiseptic agent for hand hygiene prevented a few more infections per year, additional expenditures for antiseptic agents would be offset by cost savings

    Creepy (not KREEPy) Gold-Indium Intermetallic Compounds on Secondary Ion Mass Spectrometry Samples

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    A series of Secondary Ion Mass Spectrometry (SIMS) sessions to measure hydrogen (H) in Martian meteorite minerals was completed using the Cameca 6f SIMS and NanoSIMS 50L at Arizona State University (ASU). During these sessions, a creeping phenomenon has occurred, where the edges of samples pressed in indium are covered by a metal alloy. We summarize these observations herein, present a collection of preliminary data, and discuss explanations and concerns for future SIMS work. We conclude the report with a research plan for further study

    Can Money Change Who We Are? Estimating the Effects of Unearned Income on Measures of Incentive-Enhancing Personality Traits

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    The importance of noncognitive childhood skills in predicting higher wages is well documented in economics. This paper studies the reverse. Using surveys of lottery winners, we analyze the effects of unearned income on the Big Five personality traits. After correcting for potential endogeneity problems from prize sizes, we find that unearned income improves traits that predict pro-social and cooperative behaviors, preferences for social contact, empathy, and gregariousness, and reduces individuals' tendency toward negative emotional states: known in economics literature as incentive-enhancing personality traits. Our results support the possibility of scope for later interventions to improve the personality traits of adults.noncognitive skills, personality traits, lottery winners, instrumental variables, unearned income

    Separation of biological materials in microgravity

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    Partition in aqueous two phase polymer systems is a potentially useful procedure in downstream processing of both molecular and particulate biomaterials. The potential efficiency of the process for particle and cell isolations is much higher than the useful levels already achieved. Space provides a unique environment in which to test the hypothesis that convection and settling phenomena degrade the performance of the partition process. The initial space experiment in a series of tests of this hypothesis is described
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