53,881 research outputs found

    Fuzzy audio similarity measures based on spectrum histograms and fluctuation patterns

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    Spectrum histograms and fluctuation patterns are representations of audio fragments. By comparing these representations, we can determine the similarity between the corresponding fragments. Traditionally, this is done using the Euclidian distance. We propose fuzzy similarity measures as an alternative. First we introduce some well-known fuzzy similarity measures, together with certain properties that can be desirable or useful in practice. In particular we present several forms of restrictability, which allow to reduce the computation time in practical applications. Next, we show that fuzzy similarity measures can be used to compare spectrum histograms and fluctuation patterns. Finally, we describe some experimental observations for this fuzzy approach of constructing audio similarity measures

    A model for the phase separation controlled by doping and the internal chemical pressure in different cuprate superconductors

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    In the framework of a two-band model, we study the phase separation regime of different kinds of strongly correlated charge carriers as a function of the energy splitting between the two sets of bands. The narrow (wide) band simulates the more localized (more delocalized) type of charge carriers. By assuming that the internal chemical pressure on the CuO2_2 layer due to interlayer mismatch controls the energy splitting between the two sets of states, the theoretical predictions are able to reproduce the regime of phase separation at doping higher than 1/8 in the experimental pressure-doping-TcT_c phase diagram of cuprates at large microstrain as it appears in overoxygenated La2_2CuO4_4.Comment: 8 pages, 5 figures, submitted to Phys. Rev.

    Evidence for complex order parameter in La_{1.83}Sr_{0.17}CuO_4

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    The in-plane magnetic field penetration depth (\lambda_{ab}) in single-crystal La_{1.83}Sr_{0.17}CuO_4 was investigated by means of the muon-spin rotation (\muSR) technique. The temperature dependence of \lambda^{-2}_{ab} has an inflection point around 10-15K, suggesting the presence of two superconducting gaps: a large gap (\Delta_1^d) with d-wave and a small gap (\Delta_2^s) with s-wave symmetry. The zero-temperature values of the gaps at \mu_0H=0.02T were found to be \Delta_1^d(0)=8.2(2)meV and \Delta_2^s(0)=1.57(8)meV.Comment: 5 pages, 3 figure

    h/2eh/2e--Oscillations for Correlated Electron Pairs in Disordered Mesoscopic Rings

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    The full spectrum of two interacting electrons in a disordered mesoscopic one--dimensional ring threaded by a magnetic flux is calculated numerically. For ring sizes far exceeding the one--particle localization length L1L_1 we find several h/2eh/2e--periodic states whose eigenfunctions exhibit a pairing effect. This represents the first direct observation of interaction--assisted coherent pair propagation, the pair being delocalized on the scale of the whole ring.Comment: 4 pages, uuencoded PostScript, containing 5 figures

    Exclusive electroproduction revisited: treating kinematical effects

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    Generalized parton distributions of the nucleon are accessed via exclusive leptoproduction of the real photon. While earlier analytical considerations of phenomenological observables were restricted to twist-three accuracy, i.e., taking into account only terms suppressed by a single power of the hard scale, in the present study we revisit this differential cross section within the helicity formalism and restore power-suppressed effects stemming from the process kinematics exactly. We restrict ourselves to the phenomenologically important case of lepton scattering off a longitudinally polarized nucleon, where the photon flips its helicity at most by one unit.Comment: 22 pages, 1 figur

    Mitochondrial protein import

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    The precursor of F0-ATPase subunit 9 was bound to mitochondria in the absence of a mitochondrial membrane potential (delta psi). Binding was mediated by a protease-sensitive component on the mitochondrial surface. When delta psi was reestablished, bound precursor was directly imported without prior release from the mitochondrial membranes. A chimaeric protein consisting of the complete subunit 9 precursor fused to cytosolic dihydrofolate reductase (DHFR) was also specifically bound to mitochondria in the absence of delta psi. Two other fusion proteins, consisting either of the entire presequence of subunit 9 and DHFR or of part of the presequence and DHFR, were imported in the presence of delta psi. In the absence of delta psi, however, specific binding to mitochondria did not take place. We suggest that the hydrophobic mature part of subunit 9 is involved in the delta psi-independent binding of the subunit 9 precursor to receptor sites on the mitochondrial surface
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