31,906 research outputs found

    Coarse graining scale and effectiveness of hydrodynamic modeling

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    Some basic questions about the hydrodynamical approach to relativistic heavy ion collisions are discussed aiming to clarify how far we can go with such an approach to extract useful information on the properties and dynamics of the QCD matter created. We emphasize the importance of the coarse-graining scale required for the hydrodynamic modeling which determines the space-time resolution and the associated limitations of collective flow observables. We show that certain kinds of observables can indicate the degree of inhomogeneity of the initial condition under less stringent condition than the local thermal equilibrium subjected to the coarse-graining scale compatible to the scenario.Comment: 12 pages, 4 figures, Quark Matter 201

    Robustness of quantum discord to sudden death

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    We calculate the dissipative dynamics of two-qubit quantum discord under Markovian environments. We analyze various dissipative channels such as dephasing, depolarizing, and generalized amplitude damping, assuming independent perturbation, in which each qubit is coupled to its own channel. Choosing initial conditions that manifest the so-called sudden death of entanglement, we compare the dynamics of entanglement with that of quantum discord. We show that in all cases where entanglement suddenly disappears, quantum discord vanishes only in the asymptotic limit, behaving similarly to individual decoherence of the qubits, even at finite temperatures. Hence, quantum discord is more robust than the entanglement against to decoherence so that quantum algorithms based only on quantum discord correlations may be more robust than those based on entanglement.Comment: 4 figures, 4 page

    Effect of nucleon exchange on projectile multifragmentation in the reactions of 28Si + 112Sn and 124Sn at 30 and 50 MeV/nucleon

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    Multifragmentation of quasiprojectiles was studied in reactions of 28Si beam with 112Sn and 124Sn targets at projectile energies 30 and 50 MeV/nucleon. The quasiprojectile observables were reconstructed using isotopically identified charged particles with Z_f <= 5 detected at forward angles. The nucleon exchange between projectile and target was investigated using isospin and excitation energy of reconstructed quasiprojectile. For events with total reconstructed charge equal to the charge of the beam (Z_tot = 14) the influence of beam energy and target isospin on neutron transfer was studied in detail. Simulations employing subsequently model of deep inelastic transfer, statistical model of multifragmentation and software replica of FAUST detector array were carried out. A concept of deep inelastic transfer provides good description of production of highly excited quasiprojectiles. The isospin and excitation energy of quasiprojectile were described with good overall agreement. The fragment multiplicity, charge and isospin were reproduced satisfactorily. The range of contributing impact parameters was determined using backtracing procedure.Comment: 11 pages, 8 Postscript figures, LaTeX, to appear in Phys. Rev. C ( Dec 2000

    Contemporary splinting practice in the UK for adults with neurological dysfunction: A cross-sectional survey

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    This article is made available through the Brunel Open Access Publishing Fund.Aim: To explore the contemporary splinting practice of UK occupational therapists and physiotherapists for adults with neurological dysfunction. Method: Cross-sectional online survey of members of the Association of Chartered Physiotherapists in Neurology and College of Occupational Therapists Specialist Section Neurological Practice. Results: Four hundred and twenty therapists completed the survey. Contracture management is the most common rationale for therapists splinting adults with neurological dysfunction. Other shared therapeutic goals of splinting include maintaining muscle and joint alignment, spasticity management, function, pain management and control of oedema. Considerable clinical uncertainty was uncovered in practice particularly around wearing regimens of splints. Most therapists have access to locally-derived splinting guidelines, which may contribute to this diversity of practice. Conclusions: This study provides a unique insight into aspects of contemporary splinting practice among UK therapists, who belong to a specialist neurological professional network and work in a number of different health-care settings with adults who have a neurological condition. Study findings show a wide variation in splinting practice, thereby indicating a potential need for national guidance to assist therapists in this area of clinical uncertainty. Further research is required to establish best practice parameters for splinting in neurological rehabilitation

    Characterization in bi-parameter space of a non-ideal oscillator

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    The authors thank scientific agencies CAPES, CNPq (112952/2015-1), and FAPESP (2011/ 19269-11). M. S. Baptista also thanks EPSRC (EP/I03 2606/1).Peer reviewedPostprin

    Timescale for equilibration of N/Z gradients in dinuclear systems

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    Equilibration of N/Z in binary breakup of an excited and transiently deformed projectile-like fragment (PLF*), produced in peripheral collisions of 64Zn + 27Al, 64Zn, 209Bi at E/A = 45 MeV, is examined. The composition of emitted light fragments (3<=Z<=6) changes with the decay angle of the PLF*. The most neutron-rich fragments observed are associated with a small rotation angle. A clear target dependence is observed with the largest initial N/Z correlated with the heavy, neutron-rich target. Using the rotation angle as a clock, we deduce that N/Z equilibration persists for times as long as 3-4 zs (1zs = 1 x 10^-21 s = 300 fm/c). The rate of N/Z equilibration is found to depend on the initial neutron gradient within the PLF*.Comment: 6 pages, 4 figure

    Evidence for a Very Large-Scale Fractal Structure in the Universe from Cobe Measurements

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    In this work, we analyse the temperature fluctuations of the cosmic microwave background radiation observed by COBE and show that the distribution can be fitted by a fractal distribution with a fractal dimension D=1.43±0.07 D= 1.43 \pm 0.07 . This value is in close agreement with the fractal dimension obtained by Coleman and Pietronero (1992) and Luo and Schramm (1992) from galaxy-galaxy and cluster-cluster correlations up to 100h1Mpc \sim 100 h^{-1} Mpc. The fact that the observed temperature fluctuations correspond to scales much larger than 100h1Mpc 100 h^{-1} Mpc and are signatures of the primordial density fluctuations at the recombination layer suggests that the structure of the matter at the early universe was already fractal and thus non-homogeneous on those scales. This result may have important consequences for the theoretical framework that describes the universe.Comment: 11 pages, postscript file, 2 figures available upon request. To appear in ApJ Letter
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