830 research outputs found

    A note on the genus Tocantinsia (Pisces, Nematognathi, Auchenipteridae)

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    It is argued that the catfish described by MEES (1974) as representing a new genus and a new species of the Auchenipteridae : Tocantinsia depressa, is conspecific with Glanidium piresi A. DE MIRANDA RIBEIRO (1920) and that consequently the former is a junior synonym of the latter. However, the species does not belong in the genus Glanidium, being sufficiently distinct from all other Auchenipteridae to be retained in the separate genus Tocantinsia. Therefore, its correct name is Tocantinsia piresi (A. DE MIRANDA RIBEIRO)

    Group Manifold Reduction of Dual N=1 d=10 Supergravity

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    We perform a group manifold reduction of the dual version of N=1 d=10 supergravity to four dimensions. The effects of the 3- and 4-form gauge fields in the resulting gauged N=4 d=4 supergravity are studied in particular. The example of the group manifold SU(2)xSU(2) is worked out in detail, and we compare for this case the four-dimensional scalar potential with gauged N=4 supergravity.Comment: 22 pages, revised section 3, typos corrected. Published versio

    De Sitter solutions in N=4 matter coupled supergravity

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    We investigate the scalar potential of gauged N=4 supergravity with matter. The extremum in the SU(1,1)/U(1) scalars is obtained for an arbitrary number of matter multiplets. The constraints on the matter scalars are solved in terms of an explicit parametrisation of an SO(6,6+n) element. For the case of six matter multiplets we discuss both compact and noncompact gauge groups. In an example involving noncompact groups and four scalars we find a potential with an absolute minimum and a positive cosmological constant.Comment: 14 page

    `Stringy' Newton-Cartan Gravity

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    We construct a "stringy" version of Newton-Cartan gravity in which the concept of a Galilean observer plays a central role. We present both the geodesic equations of motion for a fundamental string and the bulk equations of motion in terms of a gravitational potential which is a symmetric tensor with respect to the longitudinal directions of the string. The extension to include a non-zero cosmological constant is given. We stress the symmetries and (partial) gaugings underlying our construction. Our results provide a convenient starting point to investigate applications of the AdS/CFT correspondence based on the non-relativistic "stringy" Galilei algebra.Comment: 44 page
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