22,396 research outputs found

    On the P-representable subset of all bipartite Gaussian separable states

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    P-representability is a necessary and sufficient condition for separability of bipartite Gaussian states only for the special subset of states whose covariance matrix are Sp(2,R)Sp(2,R)Sp(2,R)\otimes Sp(2,R) locally invariant. Although this special class of states can be reached by a convenient Sp(2,R)Sp(2,R)Sp(2,R)\otimes Sp(2,R) transformation over an arbitrary covariance matrix, it represents a loss of generality, avoiding inference of many general aspects of separability of bipartite Gaussian states.Comment: Final version with new results added. Slightly more detailed than the accepted manuscript (to appear in Phys. Rev. A

    A Flexible Implementation of a Matrix Laurent Series-Based 16-Point Fast Fourier and Hartley Transforms

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    This paper describes a flexible architecture for implementing a new fast computation of the discrete Fourier and Hartley transforms, which is based on a matrix Laurent series. The device calculates the transforms based on a single bit selection operator. The hardware structure and synthesis are presented, which handled a 16-point fast transform in 65 nsec, with a Xilinx SPARTAN 3E device.Comment: 4 pages, 4 figures. IEEE VI Southern Programmable Logic Conference 201

    Associations between neck circumference and adipocytokines among adolescents

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    Neck circumference (NC) was recently introduced as a predictor of cardiovascular disease (CVD) risk factor. Adipocytokines may have a key role in the development of CVD. Aims: The purpose of this study was to examine the associations between NC and adipocytokines, such as adiponectin and leptin in Portuguese adolescents.info:eu-repo/semantics/publishedVersio

    Analytical results for long time behavior in anomalous diffusion

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    We investigate through a Generalized Langevin formalism the phenomenon of anomalous diffusion for asymptotic times, and we generalized the concept of the diffusion exponent. A method is proposed to obtain the diffusion coefficient analytically through the introduction of a time scaling factor λ\lambda. We obtain as well an exact expression for λ\lambda for all kinds of diffusion. Moreover, we show that λ\lambda is a universal parameter determined by the diffusion exponent. The results are then compared with numerical calculations and very good agreement is observed. The method is general and may be applied to many types of stochastic problem

    An Overview of Management Control Theory

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