10,160 research outputs found

    B -> pi l nu at three lattice spacings

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    The increasing accuracy of experimental results for the exclusive, semileptonic decay B -> pi l nu requires a similarly accurate calculation of the hadronic matrix elements, to determine |Vub|. We present preliminary results for the form factors of the B to light meson decay mode. Using results from three lattices in the range 5.7 <= beta <= 6.1 we study the dependence on the lattice spacing.Comment: LATTICE98(heavyqk), LaTeX, 3 pages, 4 postscript figures, uses espcrc2.st

    Estimated Errors in |Vcd|/|Vcs| from Semileptonic D Decays

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    We estimate statistical and systematic errors in the extraction of the CKM ratio |Vcd|/|Vcs| from exclusive D-meson semileptonic decays using lattice QCD and anticipated new experimental results.Comment: LATTICE98(heavyqk), LaTeX, 3 pages, 2 postscript figures, uses espcrc2.sty and hyperbasics.te

    Non-Perturbative Renormalization and the Fermilab Action

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    We discuss the application of the regularization independent (RI) scheme of Rome/Southampton to determine the normalization of heavy quark operators non-perturbatively using the Fermilab action.Comment: Lattice2003(improve), 3 pages, 2 figure

    Heavy-light meson in anisotropic lattice QCD

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    We examine whether the O(a)O(a) improved quark action on anisotropic lattices can be used as a framework for the heavy quark, which enables precision computation of matrix elements of heavy-light mesons. To this end, it is crucial to verify that a mass independent and nonperturbative tuning of the parameters is possible. As a first step, we observe the dispersion relation of heavy-light mesons on a quenched lattice using the action which is nonperturbatively tuned only for the leading terms. On a lattice with the spatial cutoff aσ−1≃a_\sigma^{-1} \simeq 1.6 GeV and the anisotropy Ο=4\xi=4, the relativity relation holds within 2% accuracy in the quark mass region aσmQ≀1.2a_\sigma m_Q \leq 1.2 with the bare anisotropy parameter tuned for the massless quark. We also apply the action to a calculation of heavy-light decay constants in the charm quark mass region.Comment: Lattice2002(heavyquark), 3 pages, 2 figure

    A perturbative determination of the parameters of an anisotropic quark action

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    The parameters of a 3+1 anisotropic quark action with Symanzik-improved glue are determined at 1-loop in perturbation theory.Comment: 3 pages, 2 figures. Talk presented at Lattice2004(improved), Fermilab, June 21-26, 200

    Relay Communication with Real Time Microgrid Simulation

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    The development of smart grids with increasing penetration of renewable energy sources into the electrical grids have raised several technical challenges for the control and monitoring. One of these challenges is the system reliability, which depends on power grids’ resilience and high integrity of data. The protective relays play vital role in the grid reliability that involves monitoring power lines and mitigating blackouts. In a large power grid, the protective relays operate locally by controlling the opening and closing of switches (breakers) in power lines, which allows to disconnect or remove from service any part of the power system when it operates in abnormal manner that might cause damage to the rest of the system. However, these relays are prone to failures, which lead random opening/closing of the breakers. Therefore, to back up the protection systems, it is necessary to study the relays failures and it effect on a large power grid. The focus of this research is the development of Hardware-in-the-Loop (HIL) Simulation that allows to safely emulate and study the power systems and relays under different operating condition. HIL is the standard industrial method for developing and testing the most complex control, protection and monitoring systems. In this HIL simulation, we use a real-time simulator as a virtual representation of a large power system connected to a real device that is a Schweitzer relay (SEL). A host computer is used to develop a simulation model of a power system and then runs in a target that is real-time target simulator that is an opal RT system. The HIL simulation contains software/hardware interface that enable to control the virtual input to the real system (SEL) and vice-versa

    Autonomy support, basic need satisfaction and the optimal functioning of adult male and female sport participants: A test of basic needs theory

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    Grounded in Basic Needs Theory (BNT; Ryan and Deci, American Psychologist, 55, 68–78, 2000a), the present study aimed to: (a) test a theoretically-based model of coach autonomy support, motivational processes and well-/ill being among a sample of adult sport participants, (b) discern which basic psychological need(s) mediate the link between autonomy support and well-/ill-being, and (c) explore gender invariance in the hypothesized model. Five hundred and thirty nine participants (Male = 271;Female = 268; Mage = 22.75) completed a multi-section questionnaire tapping the targeted variables. Structural Equation Modeling (SEM) analysis revealed that coach autonomy support predicted participants’ basic need satisfaction for autonomy, competence and relatedness. In turn, basic need satisfaction predicted greater subjective vitality when engaged in sport. Participants with low levels of autonomy were more susceptible to feeling emotionally and physically exhausted from their sport investment. Autonomy and competence partially mediated the path from autonomy support to subjective vitality. Lastly, the results supported partial invariance of the model with respect to gender

    Interplay between perturbative and non-perturbative effects with the ARES method

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    We present a new semi-numerical method to compute leading hadronisation corrections to two-jet event shapes in e+e−e^+e^- annihilation. The formalism we present utilises the dispersive approach, where the magnitude of power corrections is controlled by suitable moments of an effective strong coupling, but it can be adapted to other methods. We focus on observables where the interplay between perturbative and non-perturbative effects is crucial in determining the power corrections. A naive treatment of power corrections for some of these observables gives rise to an unphysical behaviour in the corresponding distributions for moderate observable values, thus considerably limiting the available range to fit the non-perturbative moments. We present a universal treatment to handle such observables, based on a suitable subtraction procedure, and compare our results to the analytic result in the case of total broadening. Finally, for the first time we present predictions for the thrust major, which cannot be handled with analytic methods.Comment: The revised version contains an additional figure and provides further clarification

    Evidence and rationale for expanding The Views of Nature of Science Questionnaire

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    In an attempt to understand nature of science (NOS) conceptions held by learners in greater detail, researchers have steadily become more reliant on open-ended measures. The Views of Science Questionnaire (VNOS) is the most frequently used open-ended instrument. Conceptually grounded in many of the same aspects emphasized in the Next Generation Science Standards, the VNOS-C is appropriate for capturing the views of secondary school students and adults along 10 dimensions related to NOS. However, it has been observed that the 10-item VNOS-C seems to have difficulty uncovering some particular NOS aspects, or rather respondents may need additional prompting. Two new items have been developed and administered to expand the VNOS instrument (VNOS-CE). The present study focuses on evaluating whether these items function as intended, soliciting responses for the target NOS aspects, and whether these contributions add value to the instrument as a whole. Data comes from 37 pre- and in-service elementary, middle and secondary teachers. Results suggest one of the items adds considerable breadth, eliciting responses from multiple NOS aspects, while the other adds much needed depth related to one aspect, social NOS. Implications for the field and assessment of NOS are discussed
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