8,744 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

    Applications of calculus of variations to trajectory analysis Final report

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    Applying calculus of variations to multistage rocket trajectory analysi

    Good Fences Make Good Neighbors: Endogenous Property Rights in a Game of Conflict

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    This paper derives the conditions under which property rights can arise in an anarchy equilibrium. The creation of property rights requires that players devote part of their endowment to the public good of property rights protection. In the Nash equilibrium, players contribute zero to the protection of property rights. In contrast, a king who provides property rights protection paid for by a tax on endowments can completely eliminate conflict, but such a king has an incentive to take the surplus for himself. Thus players have an incentive to find a solution that keeps power in their own hands. In a social contract, players first credibly commit part of their endowments to providing property rights and then allocate the balance of their endowments between production and conflict. While property rights can arise under a social contract if the productivity of resources relative to the size of the population is sufficiently high, these property rights may be less than perfectly secure. Nevertheless, for sufficiently high productivity of resources relative to the size of the population, the social contract welfare dominates autocracy. Key Words:

    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

    Perturbative Analysis of Spectral Singularities and Their Optical Realizations

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    We develop a perturbative method of computing spectral singularities of a Schreodinger operator defined by a general complex potential that vanishes outside a closed interval. These can be realized as zero-width resonances in optical gain media and correspond to a lasing effect that occurs at the threshold gain. Their time-reversed copies yield coherent perfect absorption of light that is also known as an antilaser. We use our general results to establish the exactness of the n-th order perturbation theory for an arbitrary complex potential consisting of n delta-functions, obtain an exact expression for the transfer matrix of these potentials, and examine spectral singularities of complex barrier potentials of arbitrary shape. In the context of optical spectral singularities, these correspond to inhomogeneous gain media.Comment: 13 pages, 2 figures, one table, a reference added, typos correcte

    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

    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
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