18,391 research outputs found

    On the fundamental tone of minimal submanifolds with controlled extrinsic curvature

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    The aim of this paper is to obtain the fundamental tone for minimal submanifolds of the Euclidean or hyperbolic space under certain restrictions on the extrinsic curvature. We show some sufficient conditions on the norm of the second fundamental form that allow us to obtain the same upper and lower bound for the fundamental tone of minimal submanifolds in a Cartan-Hadamard ambient manifold. As an intrinsic result, we obtain a sufficient condition on the volume growth of a Cartan-Hadamard manifold to achieve the lowest bound for the fundamental tone given by McKean.Comment: 10 pages, minor corrections, accepted to Potential Analysi

    Conformal type of ends of revolution in space forms of constant sectional curvature

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    In this paper we consider the conformal type (parabolicity or non-parabolicity) of complete ends of revolution immersed in simply connected space forms of constant sectional curvature. We show that any complete end of revolution in the 33-dimensional Euclidean space or in the 33-dimensional sphere is parabolic. In the case of ends of revolution in the hyperbolic 33-dimensional space, we find sufficient conditions to attain parabolicity for complete ends of revolution using their relative position to the complete flat surfaces of revolution.Comment: 22 pages, 5 figure

    Ends, fundamental tones, and capacities of minimal submanifolds via extrinsic comparison theory

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    We study the volume of extrinsic balls and the capacity of extrinsic annuli in minimal submanifolds which are properly immersed with controlled radial sectional curvatures into an ambient manifold with a pole. The key results are concerned with the comparison of those volumes and capacities with the corresponding entities in a rotationally symmetric model manifold. Using the asymptotic behavior of the volumes and capacities we then obtain upper bounds for the number of ends as well as estimates for the fundamental tone of the submanifolds in question.Comment: 21 pages, 1 figure. arXiv admin note: text overlap with arXiv:1104.5417 by other author

    Work-Related Violence Research Project: Overview and Survey Module and Focus Group Findings

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    [Excerpt] The main goal of the contract was to provide ILAB with a newly developed set of high quality research tools (i.e., new survey questions module and related focus group protocols) and corresponding methodological recommendations to meet ILAB’s needs for collecting nationally representative, gender-disaggregated data on the prevalence, nature, and possible consequences of adult (18 years of age and older) WRV, including gender-based violence (or GBV) to the extent practicable. ILAB is particularly interested in the formal and informal sectors of one or more of the following Spanish-speaking Central American countries: Panama, Honduras, Nicaragua, El Salvador, Guatemala, and Costa Rica

    On the total curvature and extrinsic area growth of surfaces with tamed second fundamental form

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    In this paper we show that a complete and non-compact surface immersed in the Euclidean space with quadratic extrinsic area growth has finite total curvature provided the surface has tamed second fundamental form and admits total curvature. In such a case we obtain as well a generalized Chern-Osserman inequality. In the particular case of a surface of nonnegative curvature, we prove that the surface is diffeomorphic to the Euclidean plane if the surface has tamed second fundamental form, and that the surface is isometric to the Euclidean plane if the surface has strongly tamed second fundamental form. In the last part of the paper we characterize the fundamental tone of any submanifold of tamed second fundamental form immersed in an ambient space with a pole and quadratic decay of the radial sectional curvatures.Comment: 19 pages. Title changed and several improvement of the main theorems are done. arXiv admin note: text overlap with arXiv:0805.0323 by other author

    Magnetised Polish doughnuts revisited

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    We discuss a procedure to build new sequences of magnetised, equilibrium tori around Kerr black holes which combines two approaches previously considered in the literature. For simplicity we assume that the test-fluid approximation holds, and hence we neglect the self-gravity of the fluid. The models are built assuming a particular form of the angular momentum distribution from which the location and morphology of equipotential surfaces can be computed. This ansatz includes, in particular, the constant angular momentum case originally employed in the construction of thick tori - or Polish doughnuts - and it has already been used to build equilibrium sequences of purely hydrodynamical models. We discuss the properties of the new models and their dependence on the initial parameters. These new sequences can be used as initial data for magnetohydrodynamical evolutions in general relativity.Comment: 9 pages, 6 figures. Accepted for publication in Astronomy & Astrophysics July 12, 201
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