33,364 research outputs found

    Supporting Complex Scientific Database Schemas in a Grid Middleware

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    “This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder." “Copyright IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.” DOI: 10.1109/AINA.2009.129The volume of digital scientific data has increased considerably with advancing technologies of computing devices and scientific instruments. We are exploring the use of emerging Grid technologies for the management and manipulation of very large distributed scientific datasets. Taking as an example a terabyte-size scientific database with complex database schema, this paper focuses on the potential of a well-known Grid middleware - OGSA-DQP - for distributing such datasets. In particular, we investigate and extend the data type support in this system to handle a complex schema of a real scientific database - the Sloan Digital Sky Survey database

    Superfluid response in electron-doped cuprate superconductors

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    We propose a weakly coupled two-band model with dx2y2d_{x^2-y^2} pairing symmetry to account for the anomalous temperature dependence of superfluid density ρs\rho_s in electron-doped cuprate superconductors. This model gives a unified explanation to the presence of a upward curvature in ρs\rho_s near TcT_c and a weak temperature dependence of ρs\rho_s in low temperatures. Our work resolves a discrepancy in the interpretation of different experimental measurements and suggests that the pairing in electron-doped cuprates has predominately dx2y2d_{x^2-y^2} symmetry in the whole doping range.Comment: 4 pages, 3 figures, title changed and references adde

    Room-Temperature Ferrimagnet with Frustrated Antiferroelectricity: Promising Candidate Toward Multiple State Memory

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    On the basis of first-principles calculations we show that the M-type hexaferrite BaFe12O19 exhibits frustrated antiferroelectricity associated with its trigonal bipyramidal Fe3+ sites. The ferroelectric (FE) state of BaFe12O19, reachable by applying an external electric field to the antiferroelectric (AFE) state, can be made stable at room temperature by appropriate element substitution or strain engineering. Thus M-type hexaferrite, as a new type of multiferoic with coexistence of antiferroelectricity and ferrimagnetism, provide a basis for studying the phenomenon of frustrated antiferroelectricity and realizing multiple state memory devices.Comment: supporting material available via email. arXiv admin note: text overlap with arXiv:1210.7116 by other author

    The Home Market Effect and Bilateral Trade Patterns

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    We test for home-market effects using a difference-in-difference gravity specification. The home-market effect is the tendency for large countries to be net exporters of goods with high transport costs and strong scale economies. It is predicted by models of trade based on increasing returns to scale but not by models of trade based on comparative advantage. In our estimation approach, we select pairs of exporting countries that belong to a common preferential trade area and examine their exports of goods with high transport costs and strong scale economies relative to their exports of goods with low transport costs and weak scale economies. We find that home-market effects exist and that the nature of these effects depends on industry transport costs. For industries with very high transport costs, it is national market size that determines national exports. For industries with moderately high transport costs, it is neighborhood market size that matters. In this case, national market size plus market size in nearby countries determine national exports.

    The Home Market Effect and Bilateral Trade Patterns

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    We test for home-market effects using a difference-in-difference gravity specification. The home-market effect is the tendency for large countries to be net exporters of goods with high transport costs and strong scale economies. It is predicted by models of trade based on increasing returns to scale but not by models of trade based on comparative advantage. In our estimation approach, we select pairs of exporting countries that belong to a common preferential trade area and examine their exports of goods with high transport costs and strong scale economies relative to their exports of goods with low transport costs and weak scale economies. We find that home-market effects exist and that the nature of these effects depends on industry transport costs. For industries with very high transport costs, it is national market size that determines national exports. For industries with moderately high transport costs, it is neighborhood market size that matters. In this case, national market size plus market size in nearby countries determine national exports.
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