157,359 research outputs found

    Jp24 transient pressure measuring methods research status report, 1 jan. - 31 mar. 1965

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    Transient pressure transducer evaluation and improvement of laboratory electric equipment and technique

    Combining Semi-Analytic Models of Galaxy Formation with Simulations of Galaxy Clusters: the Need for AGN Heating

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    We present hydrodynamical N-body simulations of clusters of galaxies with feedback taken from semi-analytic models of galaxy formation. The advantage of this technique is that the source of feedback in our simulations is a population of galaxies that closely resembles that found in the real universe. We demonstrate that, to achieve the high entropy levels found in clusters, active galactic nuclei must inject a large fraction of their energy into the intergalactic/intracluster media throughout the growth period of the central black hole. These simulations reinforce the argument of Bower et al. (2008), who arrived at the same conclusion on the basis of purely semi-analytic reasoning.Comment: 4 pages, 1 figure. To appear in the proceedings of "The Monster's Fiery Breath", Eds. Sebastian Heinz and Eric Wilcots (AIP conference series

    Voyager observations of 1985U1

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    Of the 10 small Uranian satellites, 1985U1 is the largest and the only one for which a resolved image was obtained by Voyager 2. In terms of albedo, the other nine satellites seem to be similar. Thus the single image of 1985U1 is important in suggesting what these other objects may be like. Size, shape, surface features, and photometry are examined

    Interoperability and information sharing

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    Communication and information sharing are two of the most pressing issues facing the public safety community today. In previous chapters of this volume, authors have made note of the changing public safety landscape as it relates to the need for enhanced information and intelligence sharing among a broad cross-section of organizations. Public safety organizations, particularly law enforcement agencies, have been quick to adopt emerging technologies that have allowed for greater communication and information sharing capacities. While substantial improvements have been made over the decades that enhanced communication and information sharing, many challenges remain in the move to seamlessly integrated communication capacities. The key challenge in the upcoming decades relates to the technical and cultural changes necessary to achieve integrated communication systems. There is no shortage of resources given to increasing the communications capacity of the public safety community, yet serious challenges remain in the degree of interoperability within and across public safety domains. Interoperability has in many ways become the defining issue in the arenas of communications and information sharing. This chapter will provide an overview of critical historical events that placed questions of interoperability and information sharing on the national agenda. The chapter will also provide an overview of national models for information sharing
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