548 research outputs found

    Rejection Properties of Stochastic-Resonance-Based Detectors of Weak Harmonic Signals

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    In (V. Galdi et al., Phys. Rev. E57, 6470, 1998) a thorough characterization in terms of receiver operating characteristics (ROCs) of stochastic-resonance (SR) detectors of weak harmonic signals of known frequency in additive gaussian noise was given. It was shown that strobed sign-counting based strategies can be used to achieve a nice trade-off between performance and cost, by comparison with non-coherent correlators. Here we discuss the more realistic case where besides the sought signal (whose frequency is assumed known) further unwanted spectrally nearby signals with comparable amplitude are present. Rejection properties are discussed in terms of suitably defined false-alarm and false-dismissal probabilities for various values of interfering signal(s) strength and spectral separation.Comment: 4 pages, 5 figures. Misprints corrected. PACS numbers added. RevTeX

    On the 3D steady flow of a second grade fluid past an obstacle

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    We study steady flow of a second grade fluid past an obstacle in three space dimensions. We prove existence of solution in weighted Lebesgue spaces with anisotropic weights and thus existence of the wake region behind the obstacle. We use properties of the fundamental Oseen tensor together with results achieved in \cite{Koch} and properties of solutions to steady transport equation to get up to arbitrarily small \ep the same decay as the Oseen fundamental solution

    From endorsement of ambivalent sexism to psychological IPV victimization: The role of attitudes supportive of IPV, legitimating myths of IPV, and acceptance of psychological aggression.

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    Research on intimate partner violence (IPV) has recognized psychological abuse as a precursor of physical and sexual violence in intimate relationships. However, risk factors in predicting women’s psychological abuse victimization in such a context are still unclear. The goal of the present work was to investigate the role of ambivalent sexism on psychological IPV victimization, by taking into account in the same study the effect of three additional social-psychological factors: women’s i) attitudes supportive of IPV, ii) endorsement of legitimating myths of IPV, and iii) acceptance of psychological aggression in intimate relationships. A total of 408 Italian young women (Mage = 23.87; SD = 2.39) involved in non-marital heterosexual romantic relationships completed measures aimed at assessing i) hostile and benevolent sexism, ii) attitudes supportive of IPV, iii) legitimating myths of IPV, iv) prevalence of psychological abuse experienced within the last 12 months, and performed a task developed ad hoc to measure v) acceptance of psychological aggression in intimate relationships. Results showed that the effect of ambivalent sexism on participants’ prevalence of psychological abuse was mediated by the endorsement of attitudes supportive of IPV and legitimating myths of IPV, as well as by acceptance of psychological aggression. Findings are discussed based on literature about ambivalent sexism, and attitudes and beliefs about IP

    Mode Confinement in Photonic Quasi-Crystal Point-Defect Cavities for Particle Accelerators

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    In this Letter, we present a study of the confinement properties of point-defect resonators in finite-size photonic-bandgap structures composed of aperiodic arrangements of dielectric rods, with special emphasis on their use for the design of cavities for particle accelerators. Specifically, for representative geometries, we study the properties of the fundamental mode (as a function of the filling fraction, structure size, and losses) via 2-D and 3-D full-wave numerical simulations, as well as microwave measurements at room temperature. Results indicate that, for reduced-size structures, aperiodic geometries exhibit superior confinement properties by comparison with periodic ones.Comment: 4 pages, 4 figures, accepted for publication in Applied Physics Letter

    Evaluation of fiber-optic phase-gradient meta-tips for sensing applications

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    Recently, within the emerging framework of "lab-on-fiber" technologies, we successfully demonstrated the integration of phase-gradient plasmonic metasurfaces on the tip of an optical fiber. The res..

    Multiple double-exchange mechanism by Mn2+^{2+}-doping in manganite compounds

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    Double-exchange mechanisms in RE1−x_{1-x}AEx_{x}MnO3_{3} manganites (where RE is a trivalent rare-earth ion and AE is a divalent alkali-earth ion) relies on the strong exchange interaction between two Mn3+^{3+} and Mn4+^{4+} ions through interfiling oxygen 2p states. Nevertheless, the role of RE and AE ions has ever been considered "silent" with respect to the DE conducting mechanisms. Here we show that a new path for DE-mechanism is indeed possible by partially replacing the RE-AE elements by Mn2+^{2+}-ions, in La-deficient Lax_{x}MnO3−δ_{3-\delta} thin films. X-ray absorption spectroscopy demonstrated the relevant presence of Mn2+^{2+} ions, which is unambiguously proved to be substituted at La-site by Resonant Inelastic X-ray Scattering. Mn2+^{2+} is proved to be directly correlated to the enhanced magneto-transport properties because of an additional hopping mechanism trough interfiling Mn2+^{2+}-ions, theoretically confirmed by calculations within the effective single band model. The very idea to use Mn2+^{2+} both as a doping element and an ions electronically involved in the conduction mechanism, has never been foreseen, revealing a new phenomena in transport properties of manganites. More important, such a strategy might be also pursed in other strongly correlated materials.Comment: 6 pages, 5 figure
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