37,994 research outputs found

    Prevalence of Cytauxzoon felis (Protista: Apicomplexa) in Feral Cats in Russellville Arkansas

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    Abstract Cytauxzoon felis (C. felis) is a protozoan hemoparasite of domestic and wild felids. Transmitted by ixodid ticks, the sylvatic reservoir for this organism in North America is the bobcat (Lynx rufus) in which the infection is apparently self-limiting. In domestic cats (Felis catus), C. felis causes a highly fatal disease with a distribution that covers much of the central, southcentral and southeastern U.S. and parallels that of the primary vector, the lone star tick (Amblyomma americanum). Interestingly, there appears to be an increased survival rate in domestic cats in the geographic area of the Ozark Plateau. In this study, convenience blood samples from apparently healthy feral cats were microscopically evaluated for the presence of C. felis merozoites. Positive samples were submitted for PCR confirmation by a commercial laboratory. Results indicated a prevalence of 13% (4/32) in this population. Understanding the prevalence of C. felis infection in feral cats is central to evaluating their potential role as a reservoir for the disease and may also further our understanding about the variable pathogenicity of this organism

    Quantum communication via a continuously monitored dual spin chain

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    We analyze a recent protocol for the transmission of quantum states via a dual spin chain [Burgarth and Bose, Phys. Rev. A 71, 052315 (2005)] under the constraint that the receiver's measurement strength is finite. That is, we consider the channel where the ideal, instantaneous and complete von Neumann measurements are replaced with a more realistic continuous measurement. We show that for optimal performance the measurement strength must be "tuned" to the channel spin-spin coupling, and once this is done, one is able to achieve a similar transmission rate to that obtained with ideal measurements. The spin chain protocol thus remains effective under measurement constraints.Comment: 5 pages, revtex 4, 3 eps figure

    Quantum measurement and the first law of thermodynamics: the energy cost of measurement is the work value of the acquired information

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    The energy cost of measurement is an interesting fundamental question, and may have profound implications for quantum technologies. In the context of Maxwell's demon, it is often stated that measurement has no minimum energy cost, while information has a work value, even though these statements can appear contradictory. However, as we elucidate, these statements do no refer to the cost paid by the measuring device. Here we show that it is only when a measuring device has access to a zero temperature reservoir - that is, never - that the measurement requires no energy. All real measuring devices pay the cost that a heat engine pays to obtain the work value of the information they acquire.Comment: 4 pages, revtex4-1. v2: added a referenc

    Rapid purification of quantum systems by measuring in a feedback-controlled unbiased basis

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    Rapid-purification by feedback --- specifically, reducing the mean impurity faster than by measurement alone --- can be achieved by making the eigenbasis of the density matrix to be unbiased relative to the measurement basis. Here we further examine the protocol introduced by Combes and Jacobs [Phys.Rev.Lett. {\bf 96}, 010504 (2006)] involving continuous measurement of the observable JzJ_z for a DD-dimensional system. We rigorously re-derive the lower bound (2/3)(D+1)(2/3)(D+1) on the achievable speed-up factor, and also an upper bound, namely D2/2D^2/2, for all feedback protocols that use measurements in unbiased bases. Finally we extend our results to nn independent measurements on a register of nn qubits, and derive an upper bound on the achievable speed-up factor that scales linearly with nn.Comment: v2: published versio

    The effective average tax burden in the European Union and the USA: a computer-based calculation and comparison with the model of the European tax analyzer

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    In this paper we present a computer-based model (so-called European Tax Analyzer) for the international computation and comparison of company tax burdens. The methodology follows the forward-looking concepts for the measurement of effective average tax rates (EATR) on the basis of a model-firm. The EATR is computed for investments generating economic rents (i.e. pure profits above the market interest rate). In contrast to the prevailing approaches for calculating EATR based on separate and isolate investment projects the model-firm approach allows to calculate EATR for more complex and realistic conditions that are relevant for the decision making. Due to its flexibility another important advantage of the model-firm approach is the possibility to include the most relevant and complex provisions of the tax codes (i.e. tax systems, taxes, tax rates, and tax bases). A concrete computation and comparison of the EATR of corporations and their shareholders in five different countries reveals the wide spread between the national EATR. Moreover, for the time series 1995-2000 it could be shown that the differences between the EATR have declined a little. In spite of this convergence, however, tax distortions of competition did not become significantly less. --Tax burden comparison,capital income taxation,tax competition,tax harmonization in Europe

    Quantum error correction for continuously detected errors with any number of error channels per qubit

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    It was shown by Ahn, Wiseman, and Milburn [PRA {\bf 67}, 052310 (2003)] that feedback control could be used as a quantum error correction process for errors induced by weak continuous measurement, given one perfectly measured error channel per qubit. Here we point out that this method can be easily extended to an arbitrary number of error channels per qubit. We show that the feedback protocols generated by our method encode n2n-2 logical qubits in nn physical qubits, thus requiring just one more physical qubit than in the previous case.Comment: 4 page

    Advancing Learner Autonomy in Tefl Via Collaborative Learning

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    Learner autonomy has been defined as \u27a capacity to control important aspects of one\u27s learning\u27(Benson, 2013, p. 852). In the teaching of additional languages, learner autonomy dates back at least to the 1970s. For instance, Trim, who was a leader in the teaching of additional languages in Europe, stated that a goal of language education was to: make the process of language learning more democratic by providing the con- ceptual tools for the planning, construction and conduct of courses closely geared to the needs, motivations and characteristics of the learner and enabling him [sic] so far as possible to steer and control his own progress. (1978, p. 1

    Work function determination of promising material for thermionic converters

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    The work done to fabricate Marchuk plasma discharge tubes for measurement of the cesiated emission of lanthanum hexaboride and thoriated tungsten electrodes is described. A photon counting pyrometer was completed and is to be calibrated with a gold standard

    Experiments with a Model Water Tunnel

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    This report describes a model water tunnel built in 1928 by the NACA to investigate the possibility of using water tunnels for aerodynamic investigations at large scales. The model tunnel is similar to an open-throat wind tunnel, but uses water for the working fluid
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