2,192 research outputs found

    Exact Bethe Ansatz solution for An1A_{n-1} chains with non-SUq(n)SU_{q}(n) invariant open boundary conditions

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    The Nested Bethe Ansatz is generalized to open and independent boundary conditions depending on two continuous and two discrete free parameters. This is used to find the exact eigenvectors and eigenvalues of the An1A_{n-1} vertex models and SU(n)SU(n) spin chains with such boundary conditions. The solution is found for all diagonal families of solutions to the reflection equations in all possible combinations. The Bethe ansatz equations are used to find de first order finite size correction.Comment: Two references adde

    Exact solution of the SUq(n)SU_{q}(n) invariant quantum spin chains

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    The Nested Bethe Ansatz is generalized to open boundary conditions. This is used to find the exact eigenvectors and eigenvalues of the An1A_{n-1} vertex model with fixed open boundary conditions and the corresponding SUq(n)SU_{q}(n) invariant hamiltonian. The Bethe Ansatz equations obtained are solved in the thermodynamic limit giving the vertex model free energy and the hamiltonian ground state energy including the corresponding boundary contributions.Comment: 29 page

    Integrable open-boundary conditions for the supersymmetric t-J model. The quantum group invariant case

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    We consider integrable open--boundary conditions for the supersymmetric t--J model commuting with the number operator nn and SzS^{z}. Four families, each one depending on two arbitrary parameters, are found. We find the relation between Sklyanin's method of constructing open boundary conditions and the one for the quantum group invariant case based on Markov traces. The eigenvalue problem is solved for the new cases by generalizing the Nested Algebraic Bethe ansatz of the quantum group invariant case (which is obtained as a special limit). For the quantum group invariant case the Bethe ansatz states are shown to be highest weights of splq(2,1)spl_{q}(2,1).Comment: Latex, 24 pages. Some new comments and references. Final version to appear in Nucl. Phys.

    Boundary K-matrices for the XYZ, XXZ AND XXX spin chains

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    The general solutions for the factorization equations of the reflection matrices K±(θ)K^{\pm}(\theta) for the eight vertex and six vertex models (XYZ, XXZ and XXX chains) are found. The associated integrable magnetic Hamiltonians are explicitly derived, finding families dependig on several continuous as well as discrete parameters.Comment: 13 page

    A cross-cultural re-evaluation of the Exercise Addiction Inventory (EAI) in five countries

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    Research into the detrimental effects of excessive exercise has been conceptualized in a number of similar ways, including ‘exercise addiction’ , ‘exercise dependence’ , ‘obligatory exercising’, ‘exercise abuse’, and ‘compulsive exercise’. Among the most currently used (and psychometrically valid and reliable) instruments is the Exercise Addiction Inventory (EAI). The present study aimed to further explore the psychometric properties of the EAI by combining the datasets of a number of surveys carried out in five different countries (Denmark, Hungary, Spain, UK, and US) that have used the EAI with a total sample size of 6,031 participants. A series of multigroup confirmatory factor analyses (CFAs) were carried out examining configural invariance, metric invariance, and scalar invariance. The CFAs using the combined dataset supported the configural invariance and metric invariance but not scalar invariance. Therefore, EAI factor scores from five countries are not comparable because the use or interpretation of the scale was different in the five nations. However, the covariates of exercise addiction can be studied from a cross-cultural perspective because of the metric invariance of the scale. Gender differences among exercisers in the interpretation of the scale also emerged. The implications of the results are discussed, and it is concluded that the study’s findings will facilitate a more robust and reliable use of the EAI in future research

    Boundary K-Matrices for the Six Vertex and the n(2n-1) A_{n-1} Vertex Models

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    Boundary conditions compatible with integrability are obtained for two dimensional models by solving the factorizability equations for the reflection matrices K±(θ)K^{\pm}(\theta). For the six vertex model the general solution depending on four arbitrary parameters is found. For the An1A_{n-1} models all diagonal solutions are found. The associated integrable magnetic Hamiltonians are explicitly derived.Comment: 9 pages,latex, LPTHE-PAR 92-4

    Moving on up: Second-Line Agents as Initial Treatment for Newly-Diagnosed Patients with Chronic Phase CML

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    The treatment of chronic myelogenous leukemia (CML) was revolutionized by the development of imatinib mesylate, a small molecule inhibitor of several protein tyrosine kinases, including the ABL1 protein tyrosine kinase. The current second generation of FDA-approved ABL tyrosine kinase inhibitors, dasatinib and nilotinib, are more potent inhibitors of BCR-ABL1 kinase in vitro. Originally approved for the treatment of patients who were refractory to or intolerant of imatinib, dasatinib and nilotinib are now also FDA approved in the first-line setting. The choice of tyrosine kinase inhibitor (ie, standard or high dose imatinib, dasatinib, nilotinib) to use for initial therapy in chronic-phase CML (CML-CP) will not always be obvious. Therapy selection will depend on both clinical and molecular factors, which we will discuss in this review

    Exploiting graphic processing units parallelism to improve intelligent data acquisition system performance in JET's correlation reflectometer

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    The performance of intelligent data acquisition systems relies heavily on their processing capabilities and local bus bandwidth, especially in applications with high sample rates or high number of channels. This is the case of the self adaptive sampling rate data acquisition system installed as a pilot experiment in KG8B correlation reflectometer at JET. The system, which is based on the ITMS platform, continuously adapts the sample rate during the acquisition depending on the signal bandwidth. In order to do so it must transfer acquired data to a memory buffer in the host processor and run heavy computational algorithms for each data block. The processing capabilities of the host CPU and the bandwidth of the PXI bus limit the maximum sample rate that can be achieved, therefore limiting the maximum bandwidth of the phenomena that can be studied. Graphic processing units (GPU) are becoming an alternative for speeding up compute intensive kernels of scientific, imaging and simulation applications. However, integrating this technology into data acquisition systems is not a straight forward step, not to mention exploiting their parallelism efficiently. This paper discusses the use of GPUs with new high speed data bus interfaces to improve the performance of the self adaptive sampling rate data acquisition system installed on JET. Integration issues are discussed and performance evaluations are presente

    Arsenic, fluoride and other trace elements in the Argentina Pampean plain

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    The contents of arsenic (As), fluoride (F) and other trace elements (B, Cd, Cr, Cu, Fe, Mn, Ni, Pb, V, Zn, Ba, Si and Sr) have been determined in groundwater samples from the Langueyú creek basin, in the Argentina Pampean plain. This research aims to establish the baseline concentration and geographical distribution of trace elements in this basin. This aim has particular interest to public health in the city of Tandil where groundwater is the principal source of water for human supply. The baseline concentrations of elements in the Langueyú creek basin are in good agreement with published data from other locations of the Pampean aquifer. The arsenic limit of 10mg/l, established as provisional limit by the World Health Organization (WHO), was exceeded in 78% of the sampled wells, with As concentration increasing in the direction of groundwater flow. Concentrations of B, Cd, Cu, Cr, Fe, Mn, Ni, Pb and Zn regulated by the Argentinian Food Code (CAA) do not exceed the maximum limit for drinking water, although concentrations of Ni, Zn or Pb peaked up at some wells, probably due to pipeline corrosion. The strong correlation observed between As, F, V, Cr and B has been related to their anionic character at the groundwater natural alkaline pH that is likely associated with similar mobilization (adsorption/desorption) processes. Worst consequences for human health have arisen in areas with the highest arsenic concentration in drinking water. The conclusions of this study contribute to understand the provenance and mobilization processes of some trace elements in groundwater. It enables the decision making regarding the public health priorities and the technological treatments of water resources in urban and rural areas
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