17,424 research outputs found

    Inclusive CP Asymmetries in Semileptonic Decays of B Mesons

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    We estimate the sensitivity of single lepton CP violation measurements with respect to that of traditional di-lepton measurements. We find that the sensitivity of the single lepton method is better than that of the di-lepton method. The achievable sensitivity with the currently available data is already in the range relevant to standard model predictions. We also give general expressions for inclusive decay time distributions on Υ4S\Upsilon 4S where the other BB is not measured, which will be used to obtain time dependent asymmetries. The expression is of general use whenever one deals with inclusive time-dependent as well as time-integrated measurements in Υ(4S)B0Bˉ0\Upsilon(4S)\to B^0\bar B^0 where the final state of the other BB is not reconstructed or when only the time difference is measured.Comment: 7 pages, 1 figure. Two references added, and a few typos correcte

    Nuclear spin relaxation in ordered bimetallic chain compounds

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    A theoretical interpretation is given to recent proton spin relaxation-time (T_1) measurements on NiCu(C_7H_6N_2O_6)(H_2O)_3\cdot2H_2O, which is an ideal one-dimensional ferrimagnetic Heisenberg model system of alternating spins 1 and 1/2. The relaxation rate T_1^{-1} is formulated in temrs of the spin-wave theory and is evaluated by the use of a quantum Monte Carlo method. Calculations of the temperature and applied-field (H) dependences of T_1^{-1} are in total agreement with the experimental findings. T_1 behaves as T11H1/2T_1^{-1}\propto H^{-1/2}, which turns out an indirect observation of the quadratic dispersion relations dominating the low-energy physics of quantum ferrimagnets.Comment: 5 pages, 4 figures embedded, to appear in Phys. Lett.

    Progress Report III: Fabrication of Nanopores in Silicon Nitride Membranes using Electron-beam Lithography

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    This report describes the fabrication of a long-range orderly nanopore structure in free-standing siliconnitride membranes using electron-beam lithography (EBL). The parameter setting and challenges of eachstep are discussed

    Artificial and Biological Particles in Urban Atmosphere

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    Power-dependent internal loss in Josephson bifurcation amplifiers

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    We have studied nonlinear superconducting resonators: lambda/2 coplanar-waveguide (CPW) resonators with Josephson junctions (JJs) placed in the middle and lambda/4 CPW resonators terminated by JJs, which can be used for the qubit readout as "bifurcation amplifiers." The nonlinearity of the resonators arises from the Josephson junctions, and because of the nonlinearity, the resonators with appropriate parameters are expected to show a hysteretic response to the frequency sweep, or "bifurcation," when they are driven with a sufficiently large power. We designed and fabricated resonators whose resonant frequencies were around 10 GHz. We characterized the resonators at low temperatures, T<0.05 K, and confirmed that they indeed exhibited hysteresis. The sizes of the hysteresis, however, are sometimes considerably smaller than the predictions based on the loaded quality factor in the weak drive regime. When the discrepancy appears, it is mostly explained by taking into account the internal loss, which often increases in our resonators with increasing drive power in the relevant power range. As a possible origin of the power-dependent loss, the quasiparticle channel of conductance of the JJs is discussed.Comment: 8 pages, 9 figure

    Clostridium botulinum Type E Toxins Bind to Caco-2 Cells by a Different Mechanism from That of Type A Toxins

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    Cultured Clostridium botulinum strains produce progenitor toxins designated as 12S, 16S, and 19S toxins. The 12S toxin consists of a neurotoxin (NTX, 7S) and a non-toxic non-hemagglutinin (NTNH). The 16S and 19S toxins are formed by conjugation of the 12S toxin with hemagglutinin (HA), and the 19S toxin is a dimer of the 16S toxin. Type A cultures produce all 3 of these progenitor toxins, while type E produces only the 12S toxin. The 7S toxin is cleaved into heavy (H) and light (L) chains by a protease(s) in some strains, and the H chain has 2 domains, the N-terminus (Hn) and C-terminus (Hc). It has been reported that type A toxins bind to the intestinal cells or cultured cells via either HA or Hc. In this study, we investigated the binding of type A and E toxins to Caco-2 cells using Western blot analysis. Both the type E 7S and 12S toxins bound to the cells, with the 7S toxin binding more strongly, whereas, in the type A strain, only the 16S/19S toxins showed obvious binding. Pre-incubation of the type E 7S toxin with IgG against recombinant type E Hc significantly inhibited the 7S toxin binding, indicating that Hc might be a main binding domain of the type E toxin

    Fuzzy H-infinity output feedback control of nonlinear systems under sampled measurements

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    This paper studies the problem of designing an H∞ fuzzy feedback control for a class of nonlinear systems described by a continuous-time fuzzy system model under sampled output measurements. The premise variables of the fuzzy system model are allowed to be unavailable. We develop a technique for designing an H∞ fuzzy feedback control that guarantees the L2 gain from an exogenous input to a controlled output is less than or equal to a prescribed value. A design algorithm for constructing the H∞ fuzzy feedback controller is given
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