742 research outputs found

    The marginally stable Bethe lattice spin glass revisited

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    Bethe lattice spins glasses are supposed to be marginally stable, i.e. their equilibrium probability distribution changes discontinuously when we add an external perturbation. So far the problem of a spin glass on a Bethe lattice has been studied only using an approximation where marginally stability is not present, which is wrong in the spin glass phase. Because of some technical difficulties, attempts at deriving a marginally stable solution have been confined to some perturbative regimes, high connectivity lattices or temperature close to the critical temperature. Using the cavity method, we propose a general non-perturbative approach to the Bethe lattice spin glass problem using approximations that should be hopeful consistent with marginal stability.Comment: 23 pages Revised version, hopefully clearer that the first one: six pages longe

    A unified stability property in spin glasses

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    Gibbs' measures in the Sherrington-Kirkpatrick type models satisfy two asymptotic stability properties, the Aizenman-Contucci stochastic stability and the Ghirlanda-Guerra identities, which play a fundamental role in our current understanding of these models. In this paper we show that one can combine these two properties very naturally into one unified stability property

    Stress-induced thermoelastic martensitic transformations and functional properties in [011]-oriented NiTiHfPd single crystals

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    The stress-induced martensitic transformation in the [011]-oriented Ni45.3Ti29.7Hf20Pd5 (at. %) single crystals in as-grown, homogenized and aged states were investigated in compression. It is experimentally shown that heat treatments of single crystals result in increase in martensitic transformation temperatures, two-fold decrease in reversible strain and increase in strain-hardening coefficient. As-grown single crystals demonstrate large temperature range of superelasticity (up to 140 K), large reversible strain (up to 4.3%) and large work output in comparison with homogenized and aged crystals

    Evolution of the double neutron star merging rate and the cosmological origin of gamma-ray burst sources

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    Evolution of the coalescence rate of double neutron stars (NS) and neutron star -- black hole (BH) binaries are computed for model galaxies with different star formation rates. Assuming gamma-ray bursts (GRB) to originate from NS+NS or NS+BH merging in distant galaxies, theoretical logN--logS distributions and tests of gamma-ray bursts (GRB) are calculated for the first time taking the computed merging rates into account. We use a flat cosmological model (Omega=1) with different values of the cosmological constant Lambda and under various assumptions about the star formation history in galaxies. The calculated source evolution predicts a 5-10 times increase of the source statistics at count rates 3-10 times lower than the exising BATSE sensitivity limit. The most important parameter in fitting the 2nd BATSE catalogue is the initial redshift of star formation, which is found to be z_*=2-5 depending on a poorly determined average spectral index of GRB.Comment: 13 pages, compressed uuencoded postscript, 6 figures. This paper has been accepted for publication in the Astrophysical Journal part

    Stable Cliff Climbing For Hexapod Robot With Articulated Body

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    The paper describes kinematic control for hexapod robot with three{segment articulated body. Forward and inverse kinematics for articulated body de- scribed. Static stability studied in case of climbing the so{called cli obstacle. Conditions for static stability during climbing sequence provided

    PLATELET FUNCTION TEST FOR THE ASSESSMENT OF THROMBOSIS AND BLEEDING RISK IN CHD PATIENTS TAKING ANTIPLATELET MEDICATIONS

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    The review concerns on the testing of platelet function in Chd patients receiving antiplatelet medications.  the results are shown of the main large-scale studies demonstrating the relationship of the residual platelet activity level with the development of ishemic and hemorrhagic complications. the analysis is done of the causes of insufficient suppressing of platelet function as the response to clopidogrel. the guidelines of major international expert organizations are discussed on problem of sensitivity to aggregants testing and possible modification of antiplatelet treatment

    INTEGRAL observations of SS433, a supercritically accreting microquasar with hard spectrum

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    Observations of SS433 by INTEGRAL carried out in March -- May 2003 are presented. SS433 is evidently detected on the INTEGRAL images of the corresponding sky region in the energy bands 25-50 and 50-100 keV. The precessional variability of the hard X-ray flux is clearly seen. The X-ray eclipse caused by the binary orbital motion is also detected. A possible origin of the hard continuum is briefly discussed.Comment: 5 pages, 6 figures. Accepted to A&A INTEGRAL special volum
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