290 research outputs found

    Bethe Ansatz and Thermodynamic Limit of Affine Quantum Group Invariant Extensions of the t-J Model

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    We have constructed a one dimensional exactly solvable model, which is based on the t-J model of strongly correlated electrons, but which has additional quantum group symmetry, ensuring the degeneration of states. We use Bethe Ansatz technique to investigate this model. The thermodynamic limit of the model is considered and equations for different density functions written down. These equations demonstrate that the additional colour degrees of freedom of the model behave as in a gauge theory, namely an arbitrary distribution of colour indices over particles leave invariant the energy of the ground state and the excitations. The SS-matrix of the model is shown to be the product of the ordinary t−Jt-J model SS-matrix and the unity matrix in the colour space.Comment: Latex, 17 page

    The Influence of Transrectal Multifocal Prostate Biopsy Under Ultrasound Control on the Degree of Infravesical Obstruction in Different Groups of Patients

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    . Prostate cancer - is a Malignant neoplasm arising from prostatic epithelium. [1] It is well known, that prostate cancer is the most common cancer in men population. Most patients, who underwent a biopsy of prostate, have expressed varying degrees of benign prostatic hyperplasia and, accordingly, symptoms, specific to the disease, including symptoms of the lower urinary (LUTS). [2], Uroflowmetry is a method widely used around the world to assess the degree of severity of infravesical obstruction [3].The aim was to determine the degree of influence of transrectal multifocal biopsy of the prostate under ultrasound control on the degree of infravesical obstruction [4].The study included patients with elevated serum PSA over 4 ng/ml with the volume (Vpr) of prostate from 20 cm³ to 90 cm³, volume of residual urine no more than 50 cm ³. Uroflowmetry was performed with the determination of the volume of residual urine at the primary treatment. At 21 day after transrectal multifocal prostate biopsy under Ultrasound control all patients underwent uroflowmetry. The age of patients ranged from 40 to 70 years. Patients were divided into 3 groups depending on the volume of the prostate gland. The first group consisted of 28 people where prostate volume ranged from 20 cm³ to 40 cm³, in the second group, consisted of 25 persons, prostate volume ranged from 41 cm³ to 60 cm³, and in the third group, consisted of 30 people, prostate volume ranged from 61 cm³ to 90 cm³. The following indicators of urofloumetry were determined as the following: voided volume, max flow rate, average flow, voiding time, flow time, time to max flow, and the volume of residual urine.This study has demonstrated a high risk of complications in patients with prostate volume of more than 60 cm3 caused by infravesical obstruction after prostate biopsy

    A New Family of Integrable Extended Multi-band Hubbard Hamiltonians

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    We consider exactly solvable 1d multi-band fermionic Hamiltonians, which have affine quantum group symmetry for all values of the deformation. The simplest Hamiltonian is a multi-band t-J model with vanishing spin-spin interaction, which is the affinization of an underlying XXZ model. We also find a multi-band generalization of standard t-J model Hamiltonian.Comment: 8 pages, LaTeX file, no figure

    Electron states in a one-dimensional random binary alloy

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    We present a model for alloys of compound semiconductors by introducing a one-dimensional binary random system where impurities are placed in one sublattice while host atoms lie on the other sublattice. The source of disorder is the stochastic fluctuation of the impurity energy from site to site. Although the system is one-dimensional and random, we demonstrate analytical and numerically the existence of extended states in the neighborhood of a given resonant energy, which match that of the host atoms.Comment: 11 pages, REVTeX, 3 PostScript figure

    Strong Movable Categories and Strong Movability of Topological Spaces

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    The paper is devoted to one of the important notions of the shape theory: that of strong movability, which was primarily introduced by K. Borsuk for metrizable compacts. A strong movability criterion is proved for topological spaces, which in particular reveals a new, categorical approach to the strong movability.Comment: 9 page
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