23,027 research outputs found

    Publications of the exobiology program for 1984: A special bibliography

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    A bibliography of NASA exobiology programs is given. Planetary environments; chemical evolution; organic geochemistry; extraterrestrial intelligence; and the effect of planetary solar and astrophysical phenomena on the evolution of complex life in the universe are among the topics listed

    NOSS/ALDCS analysis and system requirements definition

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    The results of system analyses and implementation studies of an advanced location and data collection system (ALDCS) , proposed for inclusion on the National Oceanic Satellite System (NOSS) spacecraft are reported. The system applies Doppler processing and radiofrequency interferometer position location technqiues both alone and in combination. Aspects analyzed include: the constraints imposed by random access to the system by platforms, the RF link parameters, geometric concepts of position and velocity estimation by the two techniques considered, and the effects of electrical measurement errors, spacecraft attitude errors, and geometric parameters on estimation accuracy. Hardware techniques and trade-offs for interferometric phase measurement, ambiguity resolution and calibration are considered. A combined Doppler-interferometer ALDCS intended to fulfill the NOSS data validation and oceanic research support mission is also described

    Analysis of Meteorological Satellite location and data collection system concepts

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    A satellite system that employs a spaceborne RF interferometer to determine the location and velocity of data collection platforms attached to meteorological balloons is proposed. This meteorological advanced location and data collection system (MALDCS) is intended to fly aboard a low polar orbiting satellite. The flight instrument configuration includes antennas supported on long deployable booms. The platform location and velocity estimation errors introduced by the dynamic and thermal behavior of the antenna booms and the effects of the presence of the booms on the performance of the spacecraft's attitude control system, and the control system design considerations critical to stable operations are examined. The physical parameters of the Astromast type of deployable boom were used in the dynamic and thermal boom analysis, and the TIROS N system was assumed for the attitude control analysis. Velocity estimation error versus boom length was determined. There was an optimum, minimum error, antenna separation distance. A description of the proposed MALDCS system and a discussion of ambiguity resolution are included

    Observation of Single Transits in Supercooled Monatomic Liquids

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    A transit is the motion of a system from one many-particle potential energy valley to another. We report the observation of transits in molecular dynamics (MD) calculations of supercooled liquid argon and sodium. Each transit is a correlated simultaneous shift in the equilibrium positions of a small local group of particles, as revealed in the fluctuating graphs of the particle coordinates versus time. This is the first reported direct observation of transit motion in a monatomic liquid in thermal equilibrium. We found transits involving 2 to 11 particles, having mean shift in equilibrium position on the order of 0.4 R_1 in argon and 0.25 R_1 in sodium, where R_1 is the nearest neighbor distance. The time it takes for a transit to occur is approximately one mean vibrational period, confirming that transits are fast.Comment: 19 pages, 8 figure

    The Elder Economic Security Standard(TM) Index for California, 2007: County Amounts, Comparisons and Components

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    Provides county-by-county data on how much income retirees need to make ends meet, how it compares with the Federal Poverty Line, and by how much the maximum Supplemental Security Income payment and average Social Security payment each fall short

    The Disappearing State Corporate Income Tax

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    This paper examines alternative explanations for the decline over the past two decades in state corporate income taxes relative to the state economy. We employ a survey of state tax administrators, individual tax returns from Georgia and Utah, and panel data to explore the importance of tax policy, tax planning, and economic factors on the trend in state corporate taxes. We find that corporate tax planning and economic factors account for much of the relative decline and that state tax policy changes are important factors. However, federal tax changes had only a modest effect during this period. Working Paper 06-2

    The Relative Importance of Preferences for Country-of-Origin in China, France, Niger and the United States

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    Country-of-origin (COO) is an increasingly politicized credence attribute in the globalizing food system. While international policy development in this area is geographically far-reaching, the benefits of country-of-origin labels (COOL) to producers and consumers from countries in different locations and levels of economic development are not clear. Previous work investigates the importance of COO to consumers, but is typically limited in scope to consumers in one nation. In addition, little is known about the importance of COO information relative to other credence attributes, especially in non-meat food products. This study measures the benefits of COOL to an internationally diverse set of consumers (in developed and developing countries) and estimates their priority rank in policy development. The paper draws upon research in the management literature suggesting consumer information needs are not based on quality alone, but also relate to affective (emotional) and normative (social acceptance) needs. A conjoint experiment is conducted in China, France, Niger and the United States to elicit consumer preferences for COO information, organic production, and genetic modification. The results indicate COO information is not as important as genetically modified content information (France, the United States, and Niger) or organic production information (China). Findings reveal individuals with quality and food safety information needs place higher importance on genetically modified and organic food information than COO information.country-of-origin, genetic modification, organic, conjoint, onion, information, food policy, International Relations/Trade, Q13, Q18, Q17,

    A Multidimensional Homo Economicus: Cultural Dimensions of Economic Preferences in Four Countries

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    Previous work in experimental economics reveals specific differences in economic behavior, especially reciprocity and free-riding behavior, across cultures. We expand the possible pallet of cross-cultural behavioral differences that may exist. We hypothesize that different kinds of strategic interaction and individual decision-making behaviors differ across locations. The variety of experiments we use allow us to report multidimensional rather than just single dimensional differences in behavior across locations. In order to build a broad Homo Economicus we conducted economic experiments in four dissimilar locations: Hangzhou, China; Niamey, Niger; Grenoble, France; Manhattan, Kansas; and West Lafayette, Indiana. Each subject completed an ultimatum bargaining game experiment, Voluntary Contribution Mechanism experiment, time preference experiment, and risk preference experiment. Results indicate economic behavior is not independent of location. Location differences are greatest for strategic interaction behavior and less prevalent for individual decision-making behavior.Time preference, risk preference, voluntary contribution mechanism, Ultimatum bargaining game, cultural, China, France, Niger, Kansas, Indiana, US, Institutional and Behavioral Economics,

    On the accuracy of the melting curves drawn from modelling a solid as an elastic medium

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    An ongoing problem in the study of a classical many-body system is the characterization of its equilibrium behaviour by theory or numerical simulation. For purely repulsive particles, locating the melting line in the pressure-temperature plane can be especially hard if the interparticle potential has a softened core or contains some adjustable parameters. A method is hereby presented that yields reliable melting-curve topologies with negligible computational effort. It is obtained by combining the Lindemann melting criterion with a description of the solid phase as an elastic continuum. A number of examples are given in order to illustrate the scope of the method and possible shortcomings. For a two-body repulsion of Gaussian shape, the outcome of the present approach compares favourably with the more accurate but also more computationally demanding self-consistent harmonic approximation.Comment: 25 pages, 7 figure

    The Unique Role of ChatGPT in Closing the Awarding Gap

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    In the United Kingdom, there is a target to reduce the higher education awarding gap by 2031. This awarding gap refers to the educational achievement (measured by the proportionate awarding of first and upper-second classifications) between groups of students on the basis of – among other characteristics – their ethnicity, socio-economic status, and gender. The introduction of the popular artificial intelligence powered chatbot, ChatGPT, presents a unique opportunity for academics to work alongside their students to help close this awarding gap. Discussed in the context of potentially nefarious means by which ChatGPT might be used to cheat the academic system, this commentary highlights contemporary international discussions of how ChatGPT might be used positively to help students better understand complex topics and apply their understanding to alterative fields of study and employment. Though limitations exist, such as the need to both discuss the wider ethical implications of its use as well as better understand the corpus from which said knowledge is derived, this commentary acts as a ‘call-to-action’ for academic working parties to empirically test the efficacy of ChatGPT as a means of closing the awarding gap
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