124,491 research outputs found

    Plant seeds in biological research in space

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    Data of 15 years of space flight and laboratory tests of plant seeds of 20 species, mainly on the combined and separate effects of launch vibration, ionizing radiation and weightlessness, are surveyed. It is concluded that plants do not show a pronounced response to space flight factors. Conditions of return to Earth, the number of heavy cosmic ray particles striking biological targets and effects of change in magnetic an electromagnetic fields have been little studied, and that more study of growing plants in space is needed

    Logistics hardware and services control system

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    Software system permits onsite direct control of logistics operations, which include spare parts, initial installation, tool control, and repairable parts status and control, through all facets of operations. System integrates logistics actions and controls receipts, issues, loans, repairs, fabrications, and modifications and assets in predicting and allocating logistics parts and services effectively

    The Hilbert Action in Regge Calculus

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    The Hilbert action is derived for a simplicial geometry. I recover the usual Regge calculus action by way of a decomposition of the simplicial geometry into 4-dimensional cells defined by the simplicial (Delaunay) lattice as well as its dual (Voronoi) lattice. Within the simplicial geometry, the Riemann scalar curvature, the proper 4-volume, and hence, the Regge action is shown to be exact, in the sense that the definition of the action does not require one to introduce an averaging procedure, or a sequence of continuum metrics which were common in all previous derivations. It appears that the unity of these two dual lattice geometries is a salient feature of Regge calculus.Comment: 6 pages, Plain TeX, no figure

    Charge Independence and Charge Symmetry

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    Charge independence and charge symmetry are approximate symmetries of nature, violated by the perturbing effects of the mass difference between up and down quarks and by electromagnetic interactions. The observations of the symmetry breaking effects in nuclear and particle physics and the implications of those effects are reviewed.Comment: 41 pages, report # DOE/ER/40427-17-N94, Chapter for a book titled "Symmetries and Fundamental Interactions in Nuclei" eds. E.M. Henley and W. Haxton, to be published by World Scientifi

    Transverse Quark Distribution in Mesons - QCD Sum Rule Approach -

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    QCD sum rules are used to compute the first few moments of the mesonic quark momentum. Transverse, longitudinal and mixed transverse-longitudinal components are examined. The transverse size of the pion is shown to be dictated by the gluon condensate, even though the mass and the longitudinal distribution are dominated by the quark condensate. The implications of our results for color transparency physics and finite temperature QCD are discussed.Comment: 8 pages, Latex, Univ. of Washington preprint DOE/ER/40427-24-N9
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