6,346 research outputs found

    Intensificação da bovinocultura de corte: estratégias de manejo reprodutivo e sanitário.

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    Manejo reprodutivo em gado de corte; Sincronizacao do estro em bovinos; Manejo sanitario em sistemas intensivos de producao de carne; Novos metodos de avaliacao da capacidade reprodutiva de touros.bitstream/CPPSE/12479/1/PROCIDoc26RTB636.0824LV.pd

    Robustness of bipartite Gaussian entangled beams propagating in lossy channels

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    Subtle quantum properties offer exciting new prospects in optical communications. Quantum entanglement enables the secure exchange of cryptographic keys and the distribution of quantum information by teleportation. Entangled bright beams of light attract increasing interest for such tasks, since they enable the employment of well-established classical communications techniques. However, quantum resources are fragile and undergo decoherence by interaction with the environment. The unavoidable losses in the communication channel can lead to a complete destruction of useful quantum properties -- the so-called "entanglement sudden death". We investigate the precise conditions under which this phenomenon takes place for the simplest case of two light beams and demonstrate how to produce states which are robust against losses. Our study sheds new light on the intriguing properties of quantum entanglement and how they may be tamed for future applications.Comment: To be published - Nature Photonic

    Disentanglement in Bipartite Continuous-Variable Systems

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    Entanglement in bipartite continuous-variable systems is investigated in the presence of partial losses, such as those introduced by a realistic quantum communication channel, e.g. by propagation in an optical fiber. We find that entanglement can vanish completely for partial losses, in a situa- tion reminiscent of so-called entanglement sudden death. Even states with extreme squeezing may become separable after propagation in lossy channels. Having in mind the potential applications of such entangled light beams to optical communications, we investigate the conditions under which entanglement can survive for all partial losses. Different loss scenarios are examined and we derive criteria to test the robustness of entangled states. These criteria are necessary and sufficient for Gaussian states. Our study provides a framework to investigate the robustness of continuous-variable entanglement in more complex multipartite systems.Comment: Phys. Rev. A (in press

    On the Number Density of Sunyaev-Zel'dovich Clusters of Galaxies

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    If the mean properties of clusters of galaxies are well described by the entropy-driven model, the distortion induced by the cluster population on the blackbody spectrum of the Cosmic Microwave Background radiation is proportional to the total amount of intracluster gas while temperature anisotropies are dominated by the contribution of clusters of about 10^{14} solar masses. This result depends marginally on cluster parameters and it can be used to estimate the number density of clusters with enough hot gas to produce a detectable Sunyaev-Zel'dovich effect. Comparing different cosmological models, the relation depends mainly on the density parameter Omega_m. If the number density of clusters could be estimated by a different method, then this dependence could be used to constrain Omega_m.Comment: 8 pages, 3 figures, submitted to ApJ Letter

    From hysteria to somatic symptom disorders: Searching for a common psychopathological ground

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    After decades of manifold contributions aimed at defining hysteria, somatisation and conversion, such syndromes are still neglected and their nosographical definition is debated. The DSM and the ICD have undergone major changes, but their clinical utility with regards to these syndromes is still questionable. On the contrary, the Diagnostic Criteria for Psychosomatic Research represents a useful clinical instrument since it translates psychosocial variables derived from psychosomatic research into operational tools. The present paper offers an overview on the psychopathological description of syndromes such as alexithymia, hypochondriasis, health anxiety, thanatophobia, conversion symptoms, anniversary and reaction which are frequent in clinical practice, but often misdiagnosed due to their absence in the DSM and the ICD. In addition, the influence of culture and cultural changes on the modifications of psychopathological manifestations is described as a further possible source of misdiagnosing and underreporting. New psychopathologies (e.g., multiple chemical sensitivity, orthorexia/vigorexia) that resemble conversion and/or somatisation have been developed, but neither is included in nosography nor taught to clinicians. The aim of the present paper is thus to describe psychopathological manifestations of somatic symptoms and related disorders to help clinicians formulate their diagnosis on the presence of signs and symptoms that can be elicited during a clinical visit, rather than by way of exclusion of other organic or psychiatric disease only

    Caracterização de isolados de Fusarium oxysporum f. sp. Cubense por marcadores SSR e compatibilidade vegetativa.

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    O mal-do-Panamá, causado pelo fungo Fusarium oxysporum f. sp. cubense (Foc), é uma das doenças mais destrutivas da bananeira. A medida de controle mais efetiva é o uso de variedades resistentes. O surgimento de novas raças é preocupação constante e fator desafiador para os programas de melhoramento visando resistência à doença

    Noncommutative Geometry and Cosmology

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    We study some consequences of noncommutativity to homogeneous cosmologies by introducing a deformation of the commutation relation between the minisuperspace variables. The investigation is carried out for the Kantowski-Sachs model by means of a comparative study of the universe evolution in four different scenarios: the classical commutative, classical noncommutative, quantum commutative, and quantum noncommutative. The comparison is rendered transparent by the use of the Bohmian formalism of quantum trajectories. As a result of our analysis, we found that noncommutativity can modify significantly the universe evolution, but cannot alter its singular behavior in the classical context. Quantum effects, on the other hand, can originate non-singular periodic universes in both commutative and noncommutative cases. The quantum noncommutative model is shown to present interesting properties, as the capability to give rise to non-trivial dynamics in situations where its commutative counterpart is necessarily static.Comment: 22 pages, 5 figures, substantial changes in the presentation, results are the same, to appear in Physical Review
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