43,780 research outputs found

    Geometry and supersymmetry of heterotic warped flux AdS backgrounds

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    We classify the geometries of the most general warped, flux AdS backgrounds of heterotic supergravity up to two loop order in sigma model perturbation theory. We show under some mild assumptions that there are no AdSnAdS_n backgrounds with n=Ìž3n\not=3. Moreover the warp factor of AdS3_3 backgrounds is constant, the geometry is a product AdS3×M7AdS_3\times M^7 and such solutions preserve, 2, 4, 6 and 8 supersymmetries. The geometry of M7M^7 has been specified in all cases. For 2 supersymmetries, it has been found that M7M^7 admits a suitably restricted G2G_2 structure. For 4 supersymmetries, M7M^7 has an SU(3)SU(3) structure and can be described locally as a circle fibration over a 6-dimensional KT manifold. For 6 and 8 supersymmetries, M7M^7 has an SU(2)SU(2) structure and can be described locally as a S3S^3 fibration over a 4-dimensional manifold which either has an anti-self dual Weyl tensor or a hyper-K\"ahler structure, respectively. We also demonstrate a new Lichnerowicz type theorem in the presence of αâ€Č\alpha' corrections.Comment: 34 pages. Reference adde

    All Killing Superalgebras for Warped AdS Backgrounds

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    We present all the symmetry superalgebras g\mathfrak{g} of all warped AdSk×wMd−k_k\times_w M^{d-k}, k>2k>2, flux backgrounds in d=10,11d=10, 11 dimensions preserving any number of supersymmetries. First we give the conditions for g\mathfrak{g} to decompose into a direct sum of the isometry algebra of AdSk_k and that of the internal space Md−kM^{d-k}. Assuming this decomposition, we identify all symmetry superalgebras of AdS3_3 backgrounds by showing that the isometry groups of internal spaces act transitively on spheres. We demonstrate that in type II and d=11d=11 theories the AdS3_3 symmetry superalgebras may not be simple and also present all symmetry superalgebras of heterotic AdS3_3 backgrounds. Furthermore, we explicitly give the symmetry superalgebras of AdSk_k, k>3k>3, backgrounds and prove that they are all classical.Comment: 41 pages, late

    Red-giant stars in eccentric binaries

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    The unparalleled photometric data obtained by NASA’s Kepler Space Telescope has led to improved understanding of red-giant stars and binary stars. We discuss the characterization of known eccentric system, containing a solar-like oscillating red-giant primary component. We also report several new binary systems that are candidates for hosting an oscillating companion. A powerful approach to study binary stars is to combine asteroseimic techniques with light curve fitting. Seismology allows us to deduce the properties of red giants. In addition, by modeling the ellipsoidal modulations we can constrain the parameters of the binary system. An valuable independent source are ground-bases, high-resolution spectrographs

    High-shock FM transmitter Final report, phase I

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    Electronic component testing of high-shock FM TRANSMITTER

    A Descriptive Study of the Population Dynamics of Adult \u3ci\u3eDiabrotica Virgifera Virgifera\u3c/i\u3e (Coleoptera: Chrysomelidae) in Artificially Infested Corn Fields

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    The influence of corn plant phenology on the dynamics of adult western corn rootworm, Diabrotica virgifera virgifera, populations was studied during 1988 and 1989 in com fields artificially infested with eggs. Fifty percent of adult emergence from the soil occurred by day 194 in 1988 and day 203 in 1989. In both years, adult emergence was synchronized with corn flowering, eggs were recovered in soil samples approximately four days after reproductive females were first observed in the population, and oviposition was essentially complete about 25 days after it began. The number of reproductive female beetle-days accumulating per m2 was similar in both years. Approximately two times as many eggs were laid in 1988 (1239 eggs 1m2) as in 1989 (590 eggs 1m2). The difference in egg density may have been caused by differences among years in the temporal synchrony of reproductive beetles with flowering corn. Daily survival rates of adults were high while corn was flowering; exhibited a gradual decline during grain filling; and decreased rapidly during the grain drying stage

    In situ correlative measurements for the ultraviolet differential absorption lidar and the high spectral resolution lidar air quality remote sensors: 1980 PEPE/NEROS program

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    In situ correlative measurements were obtained with a NASA aircraft in support of two NASA airborne remote sensors participating in the Environmental Protection Agency's 1980persistent elevated pollution episode (PEPE) and Northeast regional oxidant study (NEROS) field program in order to provide data for evaluating the capability of two remote sensors for measuring mixing layer height, and ozone and aerosol concentrations in the troposphere during the 1980 PEPE/NEROS program. The in situ aircraft was instrumented to measure temperature, dewpoint temperature, ozone concentrations, and light scattering coefficient. In situ measurements for ten correlative missions are given and discussed. Each data set is presented in graphical and tabular format aircraft flight plans are included

    Developments in electromagnetic tomography instrumentation.

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    A new EMT sensor and instrumentation is described which combines the best features of previous systems and has a modular structure to allow for future system expansion and development

    The social, cosmopolitanism and beyond

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    First, this article will outline the metaphysics of ‘the social’ that implicitly and explicitly connects the work of lassical and contemporary cosmopolitan sociologists as different as Durkheim, Weber, Beck and Luhmann. In a second step, I will show that the cosmopolitan outlook of classical sociology is driven by exclusive differences. In understanding human affairs, both classical sociology and contemporary cosmopolitan sociology reflect a very modernist outlook of epistemological, conceptual, methodological and disciplinary rigour that separates the cultural sphere from the natural objects of concern. I will suggest that classical sociology – in order to be cosmopolitan – is forced (1) to exclude non-social and non-human objects as part of its conceptual and methodological rigour, and (2) consequently and methodologically to rule out the non-social and the non-human. Cosmopolitan sociology imagines ‘the social’ as a global, universal explanatory device to conceive and describe the non-social and non-human. In a third and final step the article draws upon the work of the French sociologist Gabriel Tarde and offers a possible alternative to the modernist social and cultural other-logics of social sciences. It argues for a inclusive conception of ‘the social’ that gives the non-social and non-human a cosmopolitan voice as well
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