903,648 research outputs found

    On the smoothness of multi-M2 brane horizons

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    We calculate the degree of horizon smoothness of multi- M2M2-brane solution with branes along a common axis. We find that the metric is generically only thrice continuously differentiable at any of the horizons. The four-form field strength is found to be only twice continuously differentiable. We work with Gaussian null-like co-ordinates which are obtained by solving geodesic equations for multi-M2M2 brane geometry. We also find different, exact co-ordinate transformations which take the metric from isotropic co-ordinates to co-ordinates in which metric is thrice differentiable at the horizon. Both methods give the same result that the multi-M2M2 brane metric is only thrice continuously differentiable at the horizon.Comment: 24 pages, reference added, modified equation for non-singularity of metri

    Possible eta-mesic 3He states within the finite rank approximation

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    We extend the method of time delay proposed by Eisenbud and Wigner, to search for unstable states formed by eta mesons and the 3He nucleus. Using few body equations to describe eta-3He elastic scattering, we predict resonances and unstable bound states within different models of the eta-N interaction. The eta-3He states predicted within this novel approach are in agreement with the recent claim of the evidence of eta-mesic 3He made by the TAPS collaboration.Comment: 10 pages LaTex, 3 figure

    M\"{o}ller and Bhabha scattering in the noncommutative standard model

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    We study the M\"{o}ller and Bhabha scattering in the noncommutative extension of the standard model(SM) using the Seiberg-Witten maps of this to first order of the noncommutative parameter θμν\theta_{\mu \nu}. We look at the angular distribution dσ/dΩd\sigma/d\Omega to explore the noncommutativity of space-time at around ΛNC∼\Lambda_{NC} \sim TeV and find that the distribution deviates significantly from the one obtained from the commutative version of the standard model.Comment: 15 pages, 14 eps figures.Text is modified a little and version to appear in Phys.Rev.

    Goal accomplishment tracking for automatic supervision of plan execution

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    It is common practice to break down plans into a series of goals or sub-goals in order to facilitate plan execution, thereby only burdening the individual agents responsible for their execution with small, easily achievable objectives at any one time, or providing a simple way of sharing these objectives amongst a group of these agents. Ensuring that plans are executed correctly is an essential part of any team management. To allow proper tracking of an agent's progress through a pre-planned set of goals, it is imperative to keep track of which of these goals have already been accomplished. This centralised approach is essential when the agent is part of a team of humans and/or robots, and goal accomplishment is not always being tracked at a low level. This paper presents a framework for an automated supervision system to keep track of changes in world states so as to chart progress through a pre-planned set of goals. An implementation of this framework on a mobile service robot is presented, and applied in an experiment which demonstrates its feasibility

    Buckling of continuously supported beams

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    Numerical analysis of buckling of continuously infinite beams using Winkler model, Pasternak model, and elastic continuu
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