40,856 research outputs found

    Bounds for eigenvalue ratios of the Laplacian

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    For a bounded domain Ω\Omega with a piecewise smooth boundary in an nn-dimensional Euclidean space Rn\mathbf{R}^{n}, we study eigenvalues of the Dirichlet eigenvalue problem of the Laplacian. First we give a general inequality for eigenvalues of the Laplacian. As an application, we study lower order eigenvalues of the Laplacian and derive the ratios of lower order eigenvalues of the Laplacian.Comment: 14 page

    Using fractals and power laws to predict the location of mineral deposits

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    Around the world the mineral exploration industry is interested in getting that small increase in probability measure on the earth's surface of where the next large undiscovered deposit might be found. In particular WMC Resources Ltd has operations world wide looking for just that edge in the detection of very large deposits of, for example, gold. Since the pioneering work of Mandelbrot, geologists have been familiar with the concept of fractals and self similarity over a few orders of magnitude for geological features. This includes the location and size of deposits within a particular mineral province. Fractal dimensions have been computed for such provinces and similarities of these aggregated measures between provinces have been noted. This paper explores the possibility of making use of known information to attempt the inverse process. That is, from lesser dimensional measures of a mineral province, for example, fractal dimension or more generally multi-fractal measures, is it possible to infer, even with small increase in probability, where the unknown (preferably large) deposits might be located

    Caching and Auditing in the RPPM Model

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    Crampton and Sellwood recently introduced a variant of relationship-based access control based on the concepts of relationships, paths and principal matching, to which we will refer as the RPPM model. In this paper, we show that the RPPM model can be extended to provide support for caching of authorization decisions and enforcement of separation of duty policies. We show that these extensions are natural and powerful. Indeed, caching provides far greater advantages in RPPM than it does in most other access control models and we are able to support a wide range of separation of duty policies.Comment: Accepted for publication at STM 2014 (without proofs, which are included in this longer version

    Possibly New Charmed Baryon States from Bˉ0ppˉD0\bar B^0\to p\bar p D^{0} Decay

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    We examine the invariant mass spectrum of D0pD^{0}p in Bˉ0ppˉD0\bar B^0\to p\bar p D^{0} decay measured by BABAR and find that through the 2-step processes of Bˉ0Bc+(D0p)pˉ\bar B^0\to {\bf B_c^+}(\to D^{0} p)\bar p, where Bc{\bf B_c} denotes a charmed baryon state, some of the peaks can be identified with the established Σc(2800)+\Sigma_c(2800)^+, Λc(2880)+\Lambda_c(2880)^+ and Λc(2940)+\Lambda_c(2940)^+. Moreover, in order to account for the measured spectrum, it is necessary to introduce a new charmed baryon resonance with (m,Γ)=(3212±20,167±34)(m,\,\Gamma)=(3212\pm 20,\,167\pm 34) MeV.Comment: 8 pages, 1 figure, title changed and discussions updated, version accepted for publication in Phys. Rev.