2,254 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

    The neural basis of responsibility attribution in decision-making

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    Social responsibility links personal behavior with societal expectations and plays a key role in affecting an agent's emotional state following a decision. However, the neural basis of responsibility attribution remains unclear. In two previous event-related brain potential (ERP) studies we found that personal responsibility modulated outcome evaluation in gambling tasks. Here we conducted a functional magnetic resonance imaging (fMRI) study to identify particular brain regions that mediate responsibility attribution. In a context involving team cooperation, participants completed a task with their teammates and on each trial received feedback about team success and individual success sequentially. We found that brain activity differed between conditions involving team success vs. team failure. Further, different brain regions were associated with reinforcement of behavior by social praise vs. monetary reward. Specifically, right temporoparietal junction (RTPJ) was associated with social pride whereas dorsal striatum and dorsal anterior cingulate cortex (ACC) were related to reinforcement of behaviors leading to personal gain. The present study provides evidence that the RTPJ is an important region for determining whether self-generated behaviors are deserving of praise in a social context

    An FBG staged monitoring method for carbon fiber reinforced plastics composite fracture status based on modulus/strain wave coupling property

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    From the sensitivity of the FBG center wavelength changing with the macro-elastic modulus and the instantaneous fracture strain wave on the surface of carbon fiber reinforced plastics (CFRP) composite, we investigate the correlation between the macro-elastic modulus (the changing rate of the FBG center wavelength during the stretching process) and the fracture status of CFRP specimen. An FBG staged monitoring method based on modulus/strain wave coupling properties designed to monitor tensile fracture state of composite has been proposed. By monitoring the change of macro-elastic modulus during the stretching process, the damage state of composite in a macro perspective is obtained; when the internal damage reaches a critical state, the fracture distribution status of CFRP specimen is captured by monitoring the strain wave response induced by stress relaxation in different locations. Simulated analysis and experimental results in this paper show that the proposed FBG staged monitoring method can achieve the identification of the damage state and the breakage position of CFRP composite effectively, with a good prospect

    Complete analysis on QED corrections to Bqτ+τB_{q}\, \to\, \tau^+\, \tau^-

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    Motivated by a dynamical enhancement of the electromagnetic corrections by a power of ΛQCD/mb\Lambda_{\mathrm{QCD}}/m_b in Bd,sμ+μB_{d,s}\, \to\, \mu^+\, \mu^- at next-to-leading order (NLO), we extend the QED factorization effects on the leptonic BB meson decays with light muon leptons to tauonic final states, Bd,sτ+τB_{d,s} \, \to\, \tau^+\, \tau^-, using soft-collinear effective theory (SCET). This extension is necessary owing to the appearance of the large τ\tau mass, which will lead to different power counting in SCET and also different results. We provide a complete NLO electromagnetic corrections to Bd,sτ+τB_{d,s} \, \to\, \tau^+\, \tau^-, which include hard functions and hard-collinear functions below the bottom quark mass scale μb\mu_b. The power enhanced electromagnetic effects from hard-collinear contributions on Bd,sμ+μB_{d,s}\, \to\, \mu^+\, \mu^- discussed before also exist in Bd,sτ+τB_{d,s} \, \to\, \tau^+\, \tau^-. However the logarithm term arising from contributions of hard-collinear photon and lepton virtualities for Bd,sτ+τB_{d,s}\, \to\, \tau^+\, \tau^- is not large as it is in muon case due to the hard-collinear scale of τ\tau mass, which lead to only approximately 0.04%0.04\% QED corrections to the branching fraction of Bd,sτ+τB_{d,s} \, \to\, \tau^+\, \tau^- compared with overall reduction about 0.5%0.5\% in Bd,sμ+μB_{d,s}\, \to\, \mu^+\, \mu^-.Comment: 29 pages, 3 figure

    Reasons and clinical managements of canalicular laceration in 78 cases

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    AIM:To analyze the reason of canalicular laceration, and to explore the methods and techniques to raise the success rate of lacrimal canaliculi laceration anastomosis. <p>METHODS: Seventy-eight cases(78 eyes)with canalicular underwent lacrimal canaliculi laceration anastomosis through catheter support under microscope at I stage.<p>RESULTS: The operation was successful in all cases. The extubation time was at 3 months after operation. After one-year follow-up, lower lacrimal canaliculi were all unobstructed. <p>CONCLUSION: The causes of canalicular laceration laceration mostly were frustrated laceration. Receiving anastomosis under microscope at I stage was preferred and necessary. Searching nasal stump, implanting epidural catheter and anatomical reduction of the inner canthus were the keys to make the operation successful. Fake tears could also drain tear

    trans-Trismethoxy Resveratrol Decreased Fat Accumulation Dependent on Fat-6 and Fat-7 in Caenorhabditis Elegans

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    trans-Trismethoxy resveratrol (TMR) is a methyl analog of resveratrol. It is found to exhibit enhanced biological effects compared to resveratrol, such as inhibition of cancer cell growth and pro-apoptotic activities. However, the role of TMR in lipid metabolism is not fully understood. In this study, we used Caenorhabditis elegans, an in vivo nematode model which has been widely applied in disease research, including research on obesity, to investigate the effect of TMR on lipid metabolism. Treatment with TMR (100 and 200 μM) for 4 days significantly reduced triglyceride accumulation (14% and 20% reduction over the control, respectively) of C. elegans, without affecting nematode growth, food intake and reproduction. Treatment with TMR significantly downregulated stearoyl-CoA desaturase genes, fat-6 and fat-7, accompanied by a decrease in the desaturation index of fatty acids, the ratio of oleic acid to stearic acid. These results suggest that TMR inhibits fat accumulation by downregulating stearoyl-CoA desaturase in C. elegans

    Enhancement of bacteriolysis of Shuffled phage PhiX174 gene E

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    Bacterial ghosts that are generated using the regulated PhiX174 lysis gene E offer a new avenue for the study of inactivated vaccines. Here, we constructed a library of mutant gene E using a gene-shuffling technique. After screening and recombination with the prokaryotic non-fusion expression vector pBV220, two lysis plasmids were selected. Among which, a novel mutant E gene (named mE), consisting of a 74-bp non-encoding sequence at 5'-end and a 201-bp gene ΔE, significantly increased the lysis effect on prokaryotic Escherichia coli and Salmonella enteritidis. Moreover, lysis efficiency, as measured by the OD600 value, reached 1.0 (109 CFU), avoiding the bottleneck problem observed with other bacterial lysis procedures, which results in a low concentration of bacteria in suspension, and consequent low production of bacterial ghosts. Our results may provide a promising avenue for the development of bacterial ghost vaccines
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