134 research outputs found

    Soil, wheat, cabbage and drinking water iodine in relation to human iodine status and iodine deficiency disorders in Xinjiang Province, China

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    Iodine is an essential trace element for humans and animals. A lack in the diet can lead to iodine deficiency disorders (IDD) the most common manifestation being goitre, an enlargement of the thyroid gland in the neck. Infants born to severely Ideficient mothers may suffer cretinism and I-deficiency is the world's most common cause of preventable mental retardation. In many countries this problem has been tackled successfully using medical interventions such as the iodination of table salt. Xinjiang Province in northwest China is a remote desert region where goitre and cretinism have been reported for many years. People in this region do not like the taste of iodised salt and prefer to use local rock-salt with very low concentrations of iodine. As an alternative treatment, previous investigators added potassium-iodate to irrigation waters in an attempt to increase the I-concentrations of crops and animals in the food supply and the I-status of the population. Initial successes were reported but the long-term effectiveness of the method had not been tested. The present study aims to assess environmental controls on iodine uptake into the food chain and in Xinjiang had the opportunity to study three contrasting area

    Finite Word Length FIR Filter Design Using Integer Programming Over a Discrete Coefficient Space

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    The article of record as published may be found at http://dx.doi.org/10.1109/TASSP.1982.1163925Published in: IEEE Transactions on Acoustics, Speech, and Signal Processing (Volume: 30 , Issue: 4 , Aug 1982)It is demonstrated that the improvement achieved by using integer programming over simple coefficient rounding in the design of finite impulse response (FIR) filters with discrete coefficients is most significant when the discrete coefficient space is the powers-of-two space or when a specification is to be met with a given coefficient word length by increasing the filter length. Both minimax and least square error criteria are considered

    Experimental preparation of Werner state via spontaneous parametric down-conversion

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    We present an experiment of preparing Werner state via spontaneous parametric down-conversion and controlled decoherence of photons in this paper. In this experiment two independent BBO (beta-barium borate) crystals are used to produce down-conversion light beams, which are mixed to prepare Werner state.Comment: 6 pages, 4 figures and 2 table

    Optical realization of universal quantum cloning

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    Beyond the no-cloning theorem, the universal symmetric quantum cloning machine was first addressed by Buzek and Hillery. Here, we realized the one-to-two qubits Buzek-Hillery cloning machine with linear optical devices. This method relies on the representation of several qubits by a single photon. We showed that, the fidelities between the two output qubits and the original qubit are both 5/6 (which proved to be the optimal fidelity of one-to-two qubits universal cloner) for arbitrary input pure states.Comment: 5 Pages, 2 Figure

    Perturbative QCD analysis of Bā†’Ļ•Kāˆ—B \to \phi K^* decays

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    We study the first observed charmless Bā†’VVB\to VV modes, the Bā†’Ļ•Kāˆ—B\to\phi K^* decays, in perturbative QCD formalism. The obtained branching ratios B(Bā†’Ļ•Kāˆ—)āˆ¼15Ɨ10āˆ’6B(B\to\phi K^*)\sim 15 \times 10^{-6} are larger than āˆ¼9Ɨ10āˆ’6\sim 9\times 10^{-6} from QCD factorization. The comparison of the predicted magnitudes and phases of the different helicity amplitudes, and branching ratios with experimental data can test the power counting rules, the evaluation of annihilation contributions, and the mechanism of dynamical penguin enhancement in perturbative QCD, respectively.Comment: 14 pages, 2 tables, brief disscussion on hard sacle added, version to appear in PR

    Reducing the communication complexity with quantum entanglement

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    We propose a probabilistic two-party communication complexity scenario with a prior nonmaximally entangled state, which results in less communication than that is required with only classical random correlations. A simple all-optical implementation of this protocol is presented and demonstrates our conclusion.Comment: 4 Pages, 2 Figure

    Tip-functionalized carbon nanotubes under electric fields

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    We investigated the electronic structures of chemically modified carbon nanotube tips under electric fields using density functional calculations. Hydrogen, oxygen, and hydroxyl group-terminated nanotubes have been considered as field emitters or probe tips. In the case of the open-ended tubes, the field emission originates primarily from the dangling-bond states localized at the edge, whereas the pentagonal defects are the main source of the field emission in the capped tubes. The open-ended nanotube with a zigzag edge is an efficient field emitter because of the localized electronic states around the Fermi level and the atomic alignment of carbon-carbon bonds along with external electric fields. Tip functionalization alters the local density of states as well as the chemical selectivity of nanotubes in various ways. The correlations between atomic geometries of chemically functionalized tips and their electronic structures are further discussed. We propose that a hydrogen-terminated tube would be a promising probe tip for selective chemical imaging.open252

    Light cone QCD sum rules study of the semileptonic heavy ĪžQ\Xi_{Q} and ĪžQā€²\Xi'_{Q} transitions to Īž\Xi and Ī£\Sigma baryons

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    The semileptonic decays of heavy spin--1/2, Īžb(c)\Xi_{b(c)} and Īžb(c)ā€²\Xi'_{b(c)} baryons to the light spin-- 1/2, Īž\Xi and Ī£\Sigma baryons are investigated in the framework of the light cone QCD sum rules. In particular, using the most general form of the interpolating currents for the heavy baryons as well as the distribution amplitudes of the Īž\Xi and Ī£\Sigma baryons, we calculate all form factors entering the matrix elements of the corresponding effective Hamiltonians in full QCD. Having calculated the responsible form factors, we evaluate the decay rates and branching fractions of the related transitions.Comment: 30 Pages, 5 Figures and 18 Table

    Representational predicaments for employees: Their impact on perceptions of supervisors\u27 individualized consideration and on employee job satisfaction

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    A representational predicament for a subordinate vis-Ć -vis his or her immediate superior involves perceptual incongruence with the superior about the subordinate\u27s work or work context, with unfavourable implications for the employee. An instrument to measure the incidence of two types of representational predicament, being neglected and negative slanting, was developed and then validated through an initial survey of 327 employees. A subsequent substantive survey with a fresh sample of 330 employees largely supported a conceptual model linking being neglected and negative slanting to perceptions of low individualized consideration by superiors and to low overall job satisfaction. The respondents in both surveys were all Hong Kong Chinese. Two case examples drawn from qualitative interviews illustrate and support the conceptual model. Based on the research findings, we recommend some practical exercises to use in training interventions with leaders and subordinates. Ā© 2013 Copyright Taylor and Francis Group, LLC
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