40 research outputs found

    3D KINEMATICAL ANALYSIS OF BRAZILIAN FEMALE POLE VAULTERS

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    Pole Vault is one of the most technical events in track and field. Schade et al. (2005) evaluated kinematical and dynamic variables during the 2005 World Championship in Helsinki providing data of world class vaulters for comparison. Recently, Brazilian pole vaulters have obtained world class results but, despite this, no biomechanical analysis has been conducted with such athletes. Therefore, the aim of this work is the 3D kinematical analysis of the best female athletes during the “XXVII Brazilian Trophy” in 2008

    Entanglement entropy in a periodically driven Ising chain

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    In this work we study the entanglement entropy of a uniform quantum Ising chain in transverse field undergoing a periodic driving of period \u3c4. By means of Floquet theory we show that, for any subchain, the entanglement entropy tends asymptotically to a value \u3c4-periodic in time. We provide a semi-analytical formula for the leading term of this asymptotic regime: It is constant in time and obeys a volume law. The entropy in the asymptotic regime is always smaller than the thermal one: because of integrability the system locally relaxes to a generalized Gibbs ensemble (GGE) density matrix. The leading term of the asymptotic entanglement entropy is completely determined by this GGE density matrix. Remarkably, the asymptotic entropy shows marked features in correspondence to some non-equilibrium quantum phase transitions undergone by a Floquet state analog of the ground state

    Periodic steady state and interference in a periodically driven quantum system

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    We study the coherent dynamics of a quantum many-body system subject to a time-periodic driving. We argue that in many cases, destructive interference in time makes most of the quantum averages time-periodic, after an initial transient. We discuss in detail the case of a quantum Ising chain periodically driven across the critical point, finding that, as a result of quantum coherence, the system never reaches an infinite temperature state. Floquet resonance effects are moreover observed in the frequency dependence of the various observables, which display a sequence of well-defined peaks or dips. Extensions to non-integrable systems are discussed.Comment: 5 pages, 3 figures, supplementary material, Accepted by PR

    Knowledge and health care resource allocation: CME/CPD course guidelines-based efficacy.

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    BACKGROUND: Most health care systems consider continuing medical education a potential tool to improve quality of care and reduce disease management costs. Its efficacy in general practitioners needs to be further explored. OBJECTIVE: This study assesses the effectiveness of a one-year continuing medical education/continuing professional development course for general practitioners, regarding the improvement in knowledge of ARIA and GINA guidelines and compliance with them in asthma management. METHODS: Sixty general practitioners, covering 68,146 inhabitants, were randomly allocated to continuing medical education/continuing professional development (five residential events +four short distance-learning refresher courses over one year) or no training. Participants completed a questionnaire after each continuing medical education event; key questions were repeated at least twice. The Local Health Unit prescription database was used to verify prescription habits (diagnostic investigations and pharmacological therapy) and hospitalizations over one year before and after training. RESULTS: Fourteen general practitioners (46.7%) reached the cut-off of 50% attendance of the training courses. Knowledge improved significantly after training (p < 0.001, correct answers to key questions +13%). Training resulted in pharmaceutical cost containment (trained general practitioners +0.5% vs. controls +18.8%) and greater attention to diagnosis and monitoring (increase in spirometry +63.4%, p < 0.01). CONCLUSION: This study revealed an encouraging impact of educational events on improvement in general practitioner knowledge of guidelines and daily practice behavioral changes. Long-term studies of large populations are required to assess the effectiveness of education on the behavior of physicians in asthma management, and to establish the best format for educational events

    Sensors at Center for Advanced Sensors

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    Sensing applications for Homeland Security, Sensor Arrays, Wireless and Networked Sensors, Multisensor Data Fusion, and Remote Sensing are being developed at The University of Memphis\u27 Center for Advanced Sensors (CAS). In addition, many other sensor systems are being analyzed, developed and designed. This keynote paper considers the breadth and depth of the recent and current sensor research at the CAS. The paper serves as an introduction to the special session dedicated to the center. © 2009 IEEE

    Multipartite entanglement after a quantum quench

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    We study the multipartite entanglement of a quantum many-body system undergoing a quantum quench. We quantify the multipartite entanglement through the quantum Fisher information (QFI) density, and we are able to express it after a quench in terms of a generalised response function. For pure state initial conditions and in the thermodynamic limit, we can express the QFI as the fluctuations of an observable computed in the so-called diagonal ensemble. We apply the formalism to the dynamics of a quantum Ising chain, after a quench in the transverse field. In this model the asymptotic state is, in almost all cases, more than two-partite entangled. Moreover, starting from the ferromagnetic phase, we find a divergence of multipartite entanglement for small quenches closely connected to a corresponding divergence of the correlation length

    Thermalization in a periodically driven fully connected quantum Ising ferromagnet

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    By means of a Floquet analysis, we study the quantum dynamics of a fully connected Lipkin-Ising ferromagnet in a periodically driven transverse field showing that thermalization in the steady state is intimately connected to properties of the N\u2192 1e classical Hamiltonian dynamics. When the dynamics is ergodic, the Floquet spectrum obeys a Wigner-Dyson statistics and the system satisfies the eigenstate thermalization hypothesis (ETH): Independently of the initial state, local observables relax to the T= 1e thermal value, and Floquet states are delocalized in the Hilbert space. On the contrary, if the classical dynamics is regular no thermalization occurs. We further discuss the relationship between ergodicity and dynamical phase transitions, and the relevance of our results to other fully-connected periodically driven models (like the Bose-Hubbard), and possibilities of experimental realization in the case of two coupled BEC
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