8,607 research outputs found

    Electrical connector pin with wiping action

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    Electrical connector pin with wiping action to assure reliable contac

    Putting race explicitly into the CRA

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    Community Reinvestment Act of 1977

    Up Front and Beyond the Centre Line: Australian Aborigines in Elite Australian Rules Football

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    Although there has been a substantial growth in the number of Aboriginal players in the Australian Football League over the past decade, issues of structural and institutional racism have not been explored. This investigation of the assignment of players by position revealed marked patterns of difference, which tend to reflect stereotypes about Aboriginal athletes. The results are similar to research conducted in the USA and the UK but suggest even stronger patterns of differentiation

    A review of agriculture and health policies in Uganda with implications for the dissemination of biofortified crops:

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    Micronutrient deficiency is a widespread health problem in the developing world. Most efforts to combat this issue have focused on providing vitamin and mineral supplements to vulnerable population groups and/or fortifying foods through postproduction processing. The outcome of these interventions has not always been successful; particularly as isolated communities are often not reached due to logistical problems or do not regularly consume processed products. Also, supplementation interventions are frequently dependent on external funding and thus their sustainability is questionable.Micronutrient malnutrition, Government policy, General Biofortification, household food security, Nutrition policies,

    Changing Sources of Magma Generation Beneath Intra-Oceanic Islands Arcs: An Insight From the Juvenile Kohistan Island Arc, Pakistan Himalaya

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    The Kohistan arc, situated in the Pakistan Himalaya, is a Cretaceous intraoceanic island arc which was initiated during the northward movement of the Indian Plate. The arc was sutured to Asia at ca. 100 Ma. It was subsequently tilted northward when underplated by Indian continental crust during the early stages of India–Asia collision. Deep erosion of this tilted section provides a spectacular section through the whole arc sequence and offers a profound insight into the mechanisms of early stages of arc formation. Geochemical analysis and rare earth element modelling of basaltic sequences which date from the intraoceanic stages of arc development allow identification of three main magma source types in the mantle beneath the juvenile arc. The ‘E-type’ Kamila Amphibolites, with a MORB-type chemistry, form the intraoceanic basement to the arc. The ‘D-type’ Kamila Amphibolites are the earliest of the arc volcanic rocks. These were extracted from a primitive spinel-bearing mantle source, above a north-dipping subduction zone. The stratigraphically younger basalts of the Jaglot Group and Ghizar Formation of the Chalt Volcanic Group were derived from partial melting of a garnet-bearing source at greater depth. The Hunza Formation of the Chalt Volcanic Group contains the youngest mafic volcanic rocks of the intraoceanic arc. Although coeval with the Ghizar Formation of the Chalt Volcanic Group, they were generated by melting of a depleted, spinel-bearing mantle source rock and were erupted into a spatially and temporally restricted back-arc basin developed behind the volcanic front. The Chalt Volcanic Group was therefore formed from two different, adjacent, mantle source regions active at the same time. Results of REE modelling are consistent with models for intraoceanic arc formation in which the earliest volcanic rocks are derived from shallow level spinel-bearing peridotite, and later ones from a deeper garnet-bearing source. This is consistent with the melt region becoming deeper with time as subduction continues. A two-stage model is proposed for the back-arc basalts of the Hunza Formation in which a mantle source, depleted from a previous melting event, is underplated beneath the arc and later remelted during decompression as a consequence of extension and rifting of the arc

    Relativistic precession around rotating neutron stars: Effects due to frame-dragging and stellar oblateness

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    General relativity predicts that a rotating body produces a frame-dragging (or Lense-Thirring) effect: the orbital plane of a test particle in a non-equatorial orbit precesses about the body's symmetry axis. In this paper we compute the precession frequencies of circular orbits around rapidly rotating neutron stars for a variety of masses and equations of state. The precession frequencies computed are expressed as numerical functions of the orbital frequency observed at infinity. The post-Newtonian expansion of the exact precession formula is examined to identify the relative magnitudes of the precession caused by the Lense-Thirring effect, the usual Newtonian quadrupole effect and relativistic corrections. The first post-Newtonian correction to the Newtonian quadrupole precession is derived in the limit of slow rotation. We show that the post-Newtonian precession formula is a good approximation to the exact precession close to the neutron star in the slow rotation limit (up to \sim 400 Hz in the present context). The results are applied to recent RXTE observations of neutron star low-mass X-ray binaries, which display kHz quasi-periodic oscillations and, within the framework of beat frequency models, allow the measurement of both the neutron star spin frequency and the Keplerian frequency of the innermost ring of matter in the accretion disk around it. For a wide range of realistic equations of state, we find that the predicted precession frequency of this ring is close to one half of the low-frequency (\sim 20 - 35 Hz) quasi-periodic oscillations seen in several Atoll sources.Comment: 35 pages including 10 figures and 6 tables. To appear in the Astrophysical Journa

    Photovoltaic options for solar electric propulsion

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    During the past decade, a number of advances have occurred in solar cell and array technology. These advances have lead to performance improvement for both conventional space arrays and for advanced technology arrays. Performance enhancements have occurred in power density, specific power, and environmental capability. Both state-of-the-art and advanced development cells and array technology are discussed. Present technology will include rigid, rollout, and foldout flexible substrate designs, with silicon and GaAs solar cells. The use of concentrator array systems is also discussed based on both DOD and NASA efforts. The benefits of advanced lightweight array technology, for both near term and far term utilization, and of advanced high efficiency, thin, radiation resistant cells is examined. This includes gallium arsenide on germaniun substrates, indium phosphide, and thin film devices such as copper indium diselenide

    Approximate performance analysis of generalized join the shortest queue routing

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    In this paper we propose a highly accurate approximate performance analysis of a heterogeneous server system with a processor sharing service discipline and a general job-size distribution under a generalized join the shortest queue (GJSQ) routing protocol. The GJSQ routing protocol is a natural extension of the well-known join the shortest queue routing policy that takes into account the non-identical service rates in addition to the number of jobs at each server. The performance metrics that are of interest here are the equilibrium distribution and the mean and standard deviation of the number of jobs at each server. We show that the latter metrics are near-insensitive to the job-size distribution using simulation experiments. By applying a single queue approximation we model each server as a single server queue with a state-dependent arrival process, independent of other servers in the system, and derive the distribution of the number of jobs at the server. These state-dependent arrival rates are intended to capture the inherent correlation between servers in the original system and behave in a rather atypical way.Comment: 16 pages, 5 figures -- version 2 incorporates minor textual change
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