3,873 research outputs found

    Kunsia tomentosus (Rodentia: Cricetidae)

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    Kunsia tomentosus (Lichtenstein, 1830), the woolly giant rat, is a semifossorial cricetid typically associated with the Cerrado and Beni domains in central South America. Kunsia was recently revised and includes only 1 species. It is the largest extant sigmondontine and is readily distinguishable by its size, a body covered with dark-gray fur that is coarse and dense, moderately short tail, short limbs, bicolored manus and pes, and long, powerful claws. It inhabits primarily open grasslands and savannas from central and southwestern Brazil and northern Bolivia. K. tomentosus presently is not considered threatened; however, westernmost populations have presumably been extirpated in the past 2 centuries.Fil: Bezerra, Alexandra M. R.. Universidade do Brasília; Brasil. Escola Nacional de Saude Publica Sergio Arouca. Fundación Oswaldo Cruz; BrasilFil: Pardiñas, Ulises Francisco J.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Diversidad y Evolución Austral; Argentin

    Reply to "Comment on 'Gravitating Magnetic Monopole in the Global Monopole Spacetime' "

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    In this Reply I present some arguments in favor of the stability of the topological defect composed by global and magnetic monopoles.Comment: 1 page, no figures. Revised version improves the theoretical analysis about electrostatic self-interaction in the global monopole spacetim

    Electrostatic in Reissner-Nordstrom space-time with a conical defect

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    We calculate the electrostatic potential generated by a point charge in the space-time of Reissner-Nordstrom with a conical defect. An expression for the self-energy is also presented.Comment: 7 pages, LATEX fil

    Parabolic dunes in north-eastern Brazil

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    In this work we present measurements of vegetation cover over parabolic dunes with different degree of activation along the north-eastern Brazilian coast. We are able to extend the local values of the vegetation cover density to the whole dune by correlating measurements with the gray-scale levels of a high resolution satellite image of the dune field. The empirical vegetation distribution is finally used to validate the results of a recent continuous model of dune motion coupling sand erosion and vegetation growth.Comment: 18 pages, 14 figures, aubmitted to Geomorpholog

    Gravity and Geometric Phases

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    The behavior of a quantum test particle satisfying the Klein-Gordon equation in a certain class of 4 dimensional stationary space-times is examined. In a space-time of a spinning cosmic string, the wave function of a particle in a box is shown to acquire a geometric phase when the box is transported around a closed path surrounding the string. When interpreted as an Aharonov-Anandan geometric phase, the effect is shown to be related to the Aharonov-Bohm effect.Comment: 11 pages, latex fil

    Vacuum Polarization in the Spacetime of a Scalar-Tensor Cosmic String

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    We study the vacuum polarization effect in the spacetime generated by a magnetic flux cosmic string in the framework of a scalar-tensor gravity. The vacuum expectation values of the energy-momentum tensor of a conformally coupled scalar field are calculated. The dilaton's contribution to the vacuum polarization effect is shown explicitly.Comment: 11 pages, LATEX file, 2 eps figure

    Dilaton Gravity with a Non-minmally Coupled Scalar Field

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    We discuss the two-dimensional dilaton gravity with a scalar field as the source matter. The coupling between the gravity and the scalar, massless, field is presented in an unusual form. We work out two examples of these couplings and solutions with black-hole behaviour are discussed and compared with those found in the literature
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