5,177 research outputs found

    Panleucopenia felina : una revisión

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    En este trabajo se realiza una revisión bibliográfica sobre la panleucopenia del gato, Se describe la etiología, patogenia, cuadro clínico, tratamiento y profilaxis, Se discuten en profundidad el mecanismo patogénico y las diferentes pautas vacunales.This paper concerns a bibliographic revision on panleukopaenia in the cat. The aetiology, pathogeny, clinical picture, treatrnent and propbylaxis are described Details of the pathogenic mechanism and diverse vaccination are discussed

    Ga+, In+ and Tl+ Impurities in Alkali Halide Crystals: Distortion Trends

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    A computational study of the doping of alkali halide crystals (AX: A = Na, K; X = Cl, Br) by ns2 cations (Ga+, In+ and Tl+) is presented. Active clusters of increasing size (from 33 to 177 ions) are considered in order to deal with the large scale distortions induced by the substitutional impurities. Those clusters are embedded in accurate quantum environments representing the surrounding crystalline lattice. The convergence of the distortion results with the size of the active cluster is analyced for some selected impurity systems. The most important conclusion from this study is that distortions along the (100) and (110) crystallographic directions are not independent. Once a reliable cluster model is found, distortion trends as a function of impurity, alkali cation and halide anion are identified and discussed. These trends may be useful when analycing other cation impurities in similar host lattices.Comment: LaTeX file. 7 pages and 2 pictures. Accepted for publication in J. Chem. Phy

    Individually-rational collective choice

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    There is a collection of exogenously given socially-feasible sets, and, for each one of them, each individual in a group chooses from an individually-feasible set. The fact that the product of the individually-feasible sets is larger than the socially-feasible set notwithstanding, there arises no conflict between individual choices. Assuming that individual preferences are random, I characterize rationalizable collective choices

    Long range absorption in the scattering of 6He on 208Pb and 197Au at 27 MeV

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    Quasi-elastic scattering of 6He at E_lab=27 MeV from 197Au has been measured in the angular range of 6-72 degrees in the laboratory system employing LEDA and LAMP detection systems. These data, along with previously analysed data of 6He + 208Pb at the same energy, are analyzed using Optical Model calculations. The role of Coulomb dipole polarizability has been investigated. Large imaginary diffuseness parameters are required to fit the data. This result is an evidence for long range absorption mechanisms in 6He induced reactions.Comment: 10 pages, 10 figures, minor corrections. To appear in Nucl. Phys.

    Maximizing the Conditional Expected Reward for Reaching the Goal

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    The paper addresses the problem of computing maximal conditional expected accumulated rewards until reaching a target state (briefly called maximal conditional expectations) in finite-state Markov decision processes where the condition is given as a reachability constraint. Conditional expectations of this type can, e.g., stand for the maximal expected termination time of probabilistic programs with non-determinism, under the condition that the program eventually terminates, or for the worst-case expected penalty to be paid, assuming that at least three deadlines are missed. The main results of the paper are (i) a polynomial-time algorithm to check the finiteness of maximal conditional expectations, (ii) PSPACE-completeness for the threshold problem in acyclic Markov decision processes where the task is to check whether the maximal conditional expectation exceeds a given threshold, (iii) a pseudo-polynomial-time algorithm for the threshold problem in the general (cyclic) case, and (iv) an exponential-time algorithm for computing the maximal conditional expectation and an optimal scheduler.Comment: 103 pages, extended version with appendices of a paper accepted at TACAS 201

    Fast Integrated Spectra Analyzer: A New Computational Tool For Age and Reddening Determination of Small Angular Diameter Open Clusters

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    We present a new algorithm called 'Fast Integrated Spectra Analyzer" (FISA) that permits fast and reasonably accurate age and reddening determinations for small angular diameter open clusters by using their integrated spectra in the (3600-7400) \AA \ range and currently available template spectrum libraries. This algorithm and its implementation help to achieve astrophysical results in shorter times than from other methods. A brief review is given of the integrated spectroscopic technique applied to the study of open clusters as well as the basic assumptions that justify its use. We describe the numerical algorithm employed in detail, show examples of its application, and provide a link to the code. Our method has successfully been applied to integrated spectroscopy of open clusters, both in the Galaxy and in the Magellanic Clouds, to determine ages and reddenings.Comment: 27 Pages, 7 Figures, 1 table. Accepted to PAS

    Rampant polyphyly indicates cryptic diversity in a clade of Neotropical flycatchers (Aves: Tyrannidae)

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    Polyphyletic arrangements in DNA phylogenies are often indicators of cryptic species diversity masked by erroneous taxonomic treatments that are frequently based on morphological data. Although mitochondrial (mt)DNA polyphyly is detected relatively rarely in phylogenetic studies, it has recently been found in a variety of tyrant-flycatcher (Tyrannidae) groups. In the present study, we provide a DNA phylogeny for a mitochondrial and a nuclear locus with a complete species sampling in Zimmerius flycatchers, showing that the genus is characterized by multiple mtDNA polyphyly. Based on phylogenetic and life-history information, we suggest the elevation of a number of taxa to species status, leading to a doubling of Zimmerius species-level diversity compared to taxonomic treatments conducted before 2001. © 2013 The Linnean Society of London

    Uniform shear flow in dissipative gases. Computer simulations of inelastic hard spheres and (frictional) elastic hard spheres

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    In the preceding paper (cond-mat/0405252), we have conjectured that the main transport properties of a dilute gas of inelastic hard spheres (IHS) can be satisfactorily captured by an equivalent gas of elastic hard spheres (EHS), provided that the latter are under the action of an effective drag force and their collision rate is reduced by a factor (1+α)/2(1+\alpha)/2 (where α\alpha is the constant coefficient of normal restitution). In this paper we test the above expectation in a paradigmatic nonequilibrium state, namely the simple or uniform shear flow, by performing Monte Carlo computer simulations of the Boltzmann equation for both classes of dissipative gases with a dissipation range 0.5α0.950.5\leq \alpha\leq 0.95 and two values of the imposed shear rate aa. The distortion of the steady-state velocity distribution from the local equilibrium state is measured by the shear stress, the normal stress differences, the cooling rate, the fourth and sixth cumulants, and the shape of the distribution itself. In particular, the simulation results seem to be consistent with an exponential overpopulation of the high-velocity tail. The EHS results are in general hardly distinguishable from the IHS ones if α0.7\alpha\gtrsim 0.7, so that the distinct signature of the IHS gas (higher anisotropy and overpopulation) only manifests itself at relatively high dissipationsComment: 23 pages; 18 figures; Figs. 2 and 9 include new simulations; two new figures added; few minor changes; accepted for publication in PR

    Critical Behavior of a Heavy Particle in a Granular Fluid

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    Behavior analogous to a second order phase transition is observed for the homogeneous cooling state of a heavy impurity particle in a granular fluid. The order parameter ϕ\phi is the ratio of impurity mean square velocity to that of the fluid, with a conjugate field hh proportional to the mass ratio. A parameter β\beta , measuring the fluid cooling rate relative to the impurity--fluid collision rate, is the analogue of the inverse temperature. For β<1\beta <1 the fluid is ``normal'' with ϕ=0\phi =0 at h=0h=0, as in the case of a system with elastic collisions. For β>1\beta >1 an ``ordered'' state with ϕ0\phi \neq 0 occurs at h=0h=0, representing an extreme breakdown of equipartition. Critical slowing and qualitative changes in the velocity distribution function for the impurity particle near the transition are notedComment: 4 pages (4 figures included
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