8,005 research outputs found

    The Structure on Invariant Measures of C1C^1 generic diffeomorphisms

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    Let Λ\Lambda be an isolated non-trival transitive set of a C1C^1 generic diffeomorphism f\in\Diff(M). We show that the space of invariant measures supported on Λ\Lambda coincides with the space of accumulation measures of time averages on one orbit. Moreover, the set of points having this property is residual in Λ\Lambda (which implies the set of irregular+^+ points is also residual in Λ\Lambda). As an application, we show that the non-uniform hyperbolicity of irregular+^+ points in Λ\Lambda with totally 0 measure (resp., the non-uniform hyperbolicity of a generic subset in Λ\Lambda) determines the uniform hyperbolicity of Λ\Lambda

    The effects of the little Higgs models on ttˉh0t\bar{t} h^0 production via γγ\gamma \gamma collision at linear colliders

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    In the frameworks of the littlest Higgs(LHLH) model and its extension with T-parity(LHTLHT), we studied the associated ttˉh0t\bar th^0 production process e+eγγttˉh0e^+ e^- \to \gamma\gamma \to t \bar t h^0 at the future e+ee^+e^- linear colliders up to QCD next-to-leading order. We present the regions of sf\sqrt{s}-f parameter space in which the LHLH and LHTLHT effects can and cannot be discovered with the criteria assumed in this paper. The production rates of process γγttˉh0\gamma\gamma \to t \bar t h^0 in different photon polarization collision modes are also discussed. We conclude that one could observe the effects contributed by the LHLH or LHTLHT model on the cross section for the process e+eγγttˉh0e^+ e^- \to \gamma\gamma \to t \bar t h^0 in a reasonable parameter space, or might put more stringent constraints on the LHLH/LHTLHT parameters in the future experiments at linear colliders.Comment: 22 pages, 25 figures, version to appear in Phys. Rev.

    Critical currents, flux-creep activation energy and potential barriers for the vortex motion from the flux creep experiments

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    We present an experimental study of thermally activated flux creep in a superconducting ring-shaped epitaxial YBCO film as well as a new way of analyzing the experimental data. The measurements were made in a wide range of temperatures between 10 and 83 K. The upper temperature limit was dictated by our experimental technique and at low temperatures we were limited by a crossover to quantum tunneling of vortices. It is shown that the experimental data can very well be described by assuming a simple thermally activated hopping of vortices or vortex bundles over potential barriers, whereby the hopping flux objects remain the same for all currents and temperatures. The new procedure of data analysis also allows to establish the current and temperature dependencies of the flux-creep activation energy U, as well as the temperature dependence of the critical current Ic, from the flux-creep rates measured at different temperatures. The variation of the activation energy with current, U(I/Ic), is then used to reconstruct the profile of the potential barriers in real space.Comment: 12 pages, 13 Postscript figures, Submitted to Physical Review

    Anomalous Crossing Frequency in Odd Proton Nuclei

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    A generic explanation for the recently observed anomalous crossing frequencies in odd proton rare earth nuclei is given. As an example, the proton 12[541]{1\over 2} [541] band in 175^{175}Ta is discussed in detail by using the angular momentum projection theory. It is shown that the quadrupole pairing interaction is decisive in delaying the crossing point and the changes in crossing frequency along the isotope chain are due to the different neutron shell fillings

    Effect of gauge boson mass on the phase structure of QED3_{3}

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    Dynamical chiral symmetry breaking (DCSB) in QED3_{3} with finite gauge boson mass is studied in the framework of the rainbow approximation of Dyson-Schwinger equations. By adopting a simple gauge boson propagator ansatz at finite temperature, we first numerically solve the Dyson-Schwinger equation for the fermion self-energy to determine the chiral phase diagram of QED3_3 with finite gauge boson mass at finite chemical potential and finite temperature, then we study the effect of the finite gauge mass on the phase diagram of QED3_3. It is found that the gauge boson mass mam_{a} suppresses the occurrence of DCSB. The area of the region in the chiral phase diagram corresponding to DCSB phase decreases as the gauge boson mass mam_{a} increases. In particular, chiral symmetry gets restored when mam_{a} is above a certain critical value. In this paper, we use DCSB to describe the antiferromagnetic order and use the gauge boson mass to describe the superconducting order. Our results give qualitatively a physical picture on the competition and coexistence between antiferromagnetic order and superconducting orders in high temperature cuprate superconductors.Comment: 10 pages, 2 figure

    Hawking-Page Phase Transition of black Dp-branes and R-charged black holes with an IR Cutoff

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    We show that the confinement-deconfinement phase transition of supersymmetric Yang-Mills theories with 16 supercharges in various dimensions can be realized through the Hawking-Page phase transition between the near horizon geometries of black Dp-branes and BPS Dp-branes by removing a small radius region in the geometry in order to realize a confinement phase, which generalizes the Herzog's discussion for the holographic hard-wall AdS/QCD model. Removing a small radius region in the gravitational dual corresponds to introducing an IR cutoff in the dual field theory. We also discuss the Hawking-Page phase transition between thermal AdS5AdS_5, AdS4AdS_4, AdS7AdS_7 spaces and R-charged AdS black holes coming from the spherical reduction of the decoupling limit of rotating D3-, M2-, and M5- branes in type IIB supergravity and 11 dimensional supergravity in grand canonical ensembles, where the IR cutoff also plays a crucial role in the existence of the phase transition.Comment: 34 pages, 18 figures, JHEP3, v2, references added, v3, some explanations adde

    Significance of Coronary Calcification for Prediction of Coronary Artery Disease and Cardiac Events Based on 64-Slice Coronary Computed Tomography Angiography

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    This work aims to validate the clinical significance of coronary artery calcium score (CACS) in predicting coronary artery disease(CAD) and cardiac events in 100 symptomatic patients (aged 37–87 years, mean 62.5, 81 males) that were followed up for a mean of 5 years. Our results showed that patients with CAD and cardiac events had significantly higher CACS than those without CAD and cardiac events, respectively. The corresponding data were 1450.42 ± 3471.24 versus 130 ± 188.29 (P 1000. Increased CACS (>100)was also associated with an increased frequency of multi-vessel disease. Nonetheless, 3 (20%) out of 15 patients with zero CACS had single-vessel disease. Significant correlation (P < 0.001) was observed between CACS and CAD on a vessel-based analysis for coronary arteries. It is concluded that CACS is significantly correlated with CAD and cardiac events

    Nano-scale superhydrophobicity: suppression of protein adsorption and promotion of flow-induced detachment

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    Wall adsorption is a common problem in microfluidic devices, particularly when proteins are used. Here we show how superhydrophobic surfaces can be used to reduce protein adsorption and to promote desorption. Hydrophobic surfaces, both smooth and having high surface roughness of varying length scales (to generate superhydrophobicity), were incubated in protein solution. The samples were then exposed to flow shear in a device designed to simulate a microfluidic environment. Results show that a similar amount of protein adsorbed onto smooth and nanometer-scale rough surfaces, although a greater amount was found to adsorb onto superhydrophobic surfaces with micrometer scale roughness. Exposure to flow shear removed a considerably larger proportion of adsorbed protein from the superhydrophobic surfaces than from the smooth ones, with almost all of the protein being removed from some nanoscale surfaces. This type of surface may therefore be useful in environments, such as microfluidics, where protein sticking is a problem and fluid flow is present. Possible mechanisms that explain the behaviour are discussed, including decreased contact between protein and surface and greater shear stress due to interfacial slip between the superhydrophobic surface and the liquid
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