10,660 research outputs found

    New Negentropy Optimization Schemes for Blind Signal Extraction of Complex Valued Sources

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    Blind signal extraction, a hot issue in the field of communication signal processing, aims to retrieve the sources through the optimization of contrast functions. Many contrasts based on higher-order statistics such as kurtosis, usually behave sensitive to outliers. Thus, to achieve robust results, nonlinear functions are utilized as contrasts to approximate the negentropy criterion, which is also a classical metric for non-Gaussianity. However, existing methods generally have a high computational cost, hence leading us to address the problem of efficient optimization of contrast function. More precisely, we design a novel “reference-based” contrast function based on negentropy approximations, and then propose a new family of algorithms (Alg.1 and Alg.2) to maximize it. Simulations confirm the convergence of our method to a separating solution, which is also analyzed in theory. We also validate the theoretic complexity analysis that Alg.2 has a much lower computational cost than Alg.1 and existing optimization methods based on negentropy criterion. Finally, experiments for the separation of single sideband signals illustrate that our method has good prospects in real-world applications

    Transport Coefficients for Holographic Hydrodynamics at Finite Energy Scale

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    We investigate the relations between black hole thermodynamics and holographic transport coefficients in this paper. The formulae for DC conductivity and diffusion coefficient are verified for electrically single-charged black holes. We examine the correctness of the proposed expressions by taking charged dilatonic and single-charged STU black holes as two concrete examples, and compute the flows of conductivity and diffusion coefficient by solving the linear order perturbation equations. We then check the consistence by evaluating the Brown-York tensor at a finite radial position. Finally, we find that the retarded Green functions for the shear modes can be expressed easily in terms of black hole thermodynamic quantities and transport coefficients.Comment: 33 pages,4 figures,to appear in Advances in High Energy Physic

    Convertible bond announcement effects: why is Japan different?

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    U.S. and Japanese firms dominate global convertible bond issuance. Previous research documents more favorable convertible bond announcement effects in Japan than in the U.S. and other developed countries. Using a global sample of convertible bonds issued from 1982 to 2012, we find that the more favorable announcement effects of Japanese convertibles are driven by their stated uses of proceeds. Japanese convertibles more often include capital expenditure as an intended use, while U.S. firms tend to mention general purposes to motivate their offering. Our findings illustrate the value to firms of being more explicit when disclosing the intended use of proceeds of security offerings

    Study on radiative decays of DsJ(2860)D^*_{sJ}(2860) and Ds1(2710)D^*_{s1}(2710) into DsD_s by means of LFQM

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    The observed resonance peak around 2.86 GeV has been carefully reexamined by the LHCb collaboration and it is found that under the peak there reside two states Ds1(2860)D^*_{s1}(2860) and Ds3(2860)D^*_{s3}(2860) which are considered as 13D1(csˉ)1^3D_1(c\bar s) and 13D3(csˉ)1^3D_3(c\bar s) with slightly different masses and total widths. Thus, the earlier assumption that the resonance Ds1(2710)D^*_{s1}(2710) was a 1D1D state should not be right. We suggest to measure the partial widths of radiative decays of DsJ(2860)D^*_{sJ}(2860) and Ds1(2710)D^*_{s1}(2710) to confirm their quantum numbers. We would consider Ds1(2710)D^*_{s1}(2710) as 23S12^3S_1 or a pure 13D11^3D_1 state, or their mixture and respectively calculate the corresponding branching ratios as well as those of DsJ(2860)D^*_{sJ}(2860). The future precise measurement would provide us information to help identifying the structures of those resonances .Comment: 8 pages, 4 figures, 1 tabl

    Induction of MET Receptor Tyrosine Kinase Down-Regulation through Antibody-Mediated Receptor Clustering

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    The proto-oncoprotein MET is a receptor tyrosine kinase that plays a key role in cancer cell growth and invasion. We have used fluorescence-tagged antibodies to activate MET in live serum-starved glioblastoma cells and monitor the fate of antibody-bound MET receptor in single cell-based assays. We found that the antibodies induced rapid and transient formation of highly polarized MET clusters on the plasma membrane and promoted the activation of MET, resembling the initial effects of binding to its ligand, HGF. However, the antibody-induced clustering and activation of MET led to the rapid removal of the receptor from cell surface and altered its intracellular processing, resulted in rapid degradation of the receptor. Consequently, while cells pre-treated with HGF remain competent to respond to further HGF stimulation, cells pre-treated with antibodies are refractory to further HGF stimulation due to antibody-mediated MET depletion. Removal of MET by sustained treatment of antibodies blocked cancer cell migration and invasion. Our studies reveal a novel mechanism to alter the recycling process of MET in glioblastoma cancer cells by promoting the receptor degradation through a proteasome-sensitive and lysosome-dependent pathway through the ligand-independent activation of MET using anti-MET antibodies
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