23,248 research outputs found

    Scaled Particle Theory for Hard Sphere Pairs. II. Numerical Analysis

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    We use the extension of scaled particle theory (ESPT) presented in the accompanying paper [Stillinger et al. J. Chem. Phys. xxx, xxx (2007)] to calculate numerically pair correlation function of the hard sphere fluid over the density range 0ρσ30.960\leq \rho\sigma^3\leq 0.96. Comparison with computer simulation results reveals that the new theory is able to capture accurately the fluid's structure across the entire density range examined. The pressure predicted via the virial route is systematically lower than simulation results, while that obtained using the compressibility route is lower than simulation predictions for ρσ30.67\rho\sigma^3\leq 0.67 and higher than simulation predictions for ρσ30.67\rho\sigma^3\geq 0.67. Numerical predictions are also presented for the surface tension and Tolman length of the hard sphere fluid

    Thermal photons from fluctuating initial conditions

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    Event-by-event fluctuations of initial QCD-matter density produced in heavy-ion collisions at RHIC enhance the production of thermal photons significantly in the region 2pT42 \le p_T \le 4 GeV/cc compared to a smooth initial-state averaged profile in the ideal hydrodynamic calculation. This enhancement is a an early time effect due to the presence of hotspots or over-dense regions in the fluctuating initial state. The effect of fluctuations is found to be stronger in peripheral than in central collisions.Comment: 4 pages, 3 figures. Talk given at Quark Matter 2011, 22-28 May 2011, Annecy, Franc

    Partnership for Health: the role of cultural and natural assets in public health

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    Strong CP violation and chiral symmetry breaking in hot and dense quark matter

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    We investigate chiral symmetry breaking and strong CP violation effects in the phase diagram of strongly interacting matter. We demonstrate the effect of strong CP violating terms on the phase structure at finite temperature and densities in a 3-flavor Nambu-Jona-Lasinio (NJL) model including the Kobayashi-Maskawa-t'Hooft (KMT) determinant term. This is investigated using an explicit structure for the ground state in terms of quark-antiquark condensates for both in the scalar and the pseudoscalar channels. CP restoring transition with temperature at zero baryon density is found to be a second order transition at θ=π\theta = \pi while the same at finite chemical potential and small temperature turns out to be a first order transition. Within the model, the tri-critical point turns out to be (Tc,μc)(273,94)(T_c,\mu_c)\simeq(273,94) MeV at θ=π\theta = \pi for such a transition.Comment: 10 pages, 12 figure

    Radially restricted linear energy transfer for high-energy protons: A new analytical approach

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    Radially restricted linear energy transfer (LET) is a basic physical parameter relevant to radiation biology and radiation protection. In this report a convenient method is presented for the analytical computation of this quantity without the need for complicated simulation. The method uses the energy-re-stricted LETL, as recently redefined in a 1993 ICRU draft document and supplements it by a relatively simple term that represents the energy of fast rays lost within distancer from the track core. The method provides a better fit than other models and is valid over the entire range of radial distance from track center to the maximum radial distance traveled by the most energetic secondary electrons.L r computed by this approach differs only a few percent from the values Contribution to the international symposium on heavy ions research: space, radiation protection and therapy, 21–24 March 1994, Sophia-Antipolis, Franc

    First excited state calculation using different phonon bases for the two-site Holstein model

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    The single-electron energy and static charge-lattice deformation correlations have been calculated for the first excited state of a two-site Holstein model within perturbative expansions using different standard phonon bases obtained through Lang-Firsov (LF) transformation, LF with squeezed phonon states, modified LF, modified LF transformation with squeezed phonon states, and also within weak-coupling perturbation approach. Comparisons of the convergence of the perturbative expansions for different phonon bases reveal that modified LF approach works much better than other approaches for major range of the coupling strength.Comment: 11 pages (REVTEX), 4 postscript figure

    Enhanced Cluster Based Routing Protocol for MANETS

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    Mobile ad-hoc networks (MANETs) are a set of self organized wireless mobile nodes that works without any predefined infrastructure. For routing data in MANETs, the routing protocols relay on mobile wireless nodes. In general, any routing protocol performance suffers i) with resource constraints and ii) due to the mobility of the nodes. Due to existing routing challenges in MANETs clustering based protocols suffers frequently with cluster head failure problem, which degrades the cluster stability. This paper proposes, Enhanced CBRP, a schema to improve the cluster stability and in-turn improves the performance of traditional cluster based routing protocol (CBRP), by electing better cluster head using weighted clustering algorithm and considering some crucial routing challenges. Moreover, proposed protocol suggests a secondary cluster head for each cluster, to increase the stability of the cluster and implicitly the network infrastructure in case of sudden failure of cluster head.Comment: 6 page

    Social prescribing: a review of community referral schemes

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    The review aims to set the scene for the conditions under which social prescribing has arisen and consider the efficacy of different referral options. Its objectives are to provide definitions, models and notable examples of social prescribing schemes and to assess the means by which and the extent to which these schemes have been evaluated. The review makes recommendations for practice, policy and future researc
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