461 research outputs found

    Reentrant Phase Transitions of the Blume-Emery-Griffiths Model for a Simple Cubic Lattice on the Cellular Automaton

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    The spin-1 Ising (BEG) model with the nearest-neighbour bilinear and biquadratic interactions and single-ion anisotropy is simulated on a cellular automaton which improved from the Creutz cellular automaton(CCA) for a simple cubic lattice. The simulations have been made for several sets of parameters K/JK/J and D/JD/J in the −3<D/J≤0-3<D/J\leq 0 and −1≤K/J≤0-1\leq K/J\leq 0 parameter regions. The re-entrant and double re-entrant phase transitions of the BEG model are determined from the temperature variations of the thermodynamic quantities (MM, QQ and χ\chi ). The phase diagrams characterizing phase transitions are compared with those obtained from other methods.Comment: 12 pages 7 figure

    Acute brucella melitensis M16 infection model in mice treated with tumor necrosis factor-alpha inhibitors

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    Introduction: There is limited data in the literature about brucellosis related to an intracellular pathogen and anti-tumor necrosis factor alpha (anti-TNFα) medication. The aim of this study was to evaluate acute Brucella infections in mice receiving anti-TNFα drug treatment. Methodology: Anti-TNFα drugs were injected in mice on the first and fifth days of the study, after which the mice were infected with B. melitensis M16 strain. Mice were sacrificed on the fourteenth day after infection. Bacterial loads in the liver and spleen were defined, and histopathological changes were evaluated. Results: Neither the liver nor the spleen showed an increased bacterial load in all anti-TNFα drug groups when compared to a non-treated, infected group. The most significant histopathological findings were neutrophil infiltrations in the red pulp of the spleen and apoptotic cells with hepatocellular pleomorphism in the liver. There was no significant difference among the groups in terms of previously reported histopathological findings, such as extramedullary hematopoiesis and granuloma formation. Conclusions: There were no differences in hepatic and splenic bacterial load and granuloma formation, which indicate worsening of the acute Brucella infection in mice; in other words, anti-TNFα treatment did not exacerbate the acute Brucella spp. infection in mice. © 2015 Kutlu et al

    First Order Phase Transition in the 3-dimensional Blume-Capel Model on a Cellular Automaton

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    The first order phase transition of the three-dimensional Blume Capel are investigated using cooling algorithm which improved from Creutz Cellular Automaton for the D/J=2.9D/J=2.9 parameter value in the first order phase transition region. The analysis of the data using the finite-size effect and the histogram technique indicate that the magnetic susceptibility maxima and the specific heat maxima increase with the system volume (LdL^{d}) at % D/J=2.9.Comment: 13 pages, 4 figure

    Psychometric validation of the Turkish nine-item Internet Gaming Disorder Scale–Short Form (IGDS9-SF)

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    The main aims of the current study were to test the factor structure, reliability and validity of the nine-item Internet Gaming Disorder Scale-Short Form (IGDS9- SF), a standardized measure to assess symptoms and prevalence of Internet Gaming Disorder (IGD). In the present study participants were assessed with the IGDS9-SF, nine-item Internet Gaming Disorder Scale (IGDS) and the Young's Internet Addiction Test-Short Form (YIAT-SF). Confirmatory factor analyses demonstrated that the factor structure (i.e., the dimensional structure) of the IGDS9-SF was satisfactory. The scale was also reliable (i.e., internally consistent with a Cronbach's alpha of 0.89) and showed adequate convergent and criterion-related validity, as indicated by statistically significant positive correlations between average time daily spent playing games during last year, IGDS and YIAT-SF scores. By applying the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) threshold for diagnosing IGD (e.g., endorsing at least five criteria), it was found that the prevalence of disordered gamers ranged from 0.96% (whole sample) to 2.57% (e-sports players). These findings support the Turkish version of the IGDS9-SF as a valid and reliable tool for determining the extent of IGD-related problems among young adults and for the purposes of early IGD diagnosis in clinical settings and similar research

    The Critical Finite Size Scaling Relation of the Order-Parameter Probability Distribution for the Three-Dimensional Ising Model on the Creutz Cellular Automaton

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    We study the order parameter probability distribution at the critical point for the three-dimensional spin-1/2 and spin-1 Ising models on the simple cubic lattice with periodic boundary conditions. The finite size scaling relation for the order parameter probability distribution is tested and verified numerically by microcanonical Creutz cellular automata simulations. The state critical exponent \delta, which characteries the far tail regime of the scaling order parameter probability distribution, is estimated for 3-d Ising models using the cellular automaton simulations at the critical temperature. The results are in good agreement with the monte carlo calculations.Comment: 8 pages 5 figure

    Transport Phenomena at a Critical Point -- Thermal Conduction in the Creutz Cellular Automaton --

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    Nature of energy transport around a critical point is studied in the Creutz cellular automaton. Fourier heat law is confirmed to hold in this model by a direct measurement of heat flow under a temperature gradient. The thermal conductivity is carefully investigated near the phase transition by the use of the Kubo formula. As the result, the thermal conductivity is found to take a finite value at the critical point contrary to some previous works. Equal-time correlation of the heat flow is also analyzed by a mean-field type approximation to investigate the temperature dependence of thermal conductivity. A variant of the Creutz cellular automaton called the Q2R is also investigated and similar results are obtained.Comment: 27 pages including 14figure

    Electronic properties of Li-doped zigzag graphene nanoribbons

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    Zigzag graphene nanoribbons (ZGNRs) are known to exhibit metallic behavior. Depending on structural properties such as edge status, doping and width of nanoribbons, the electronic properties of these structures may vary. In this study, changes in electronic properties of crystal by doping Lithium (Li) atom to ZGNR structure are analyzed. In spin polarized calculations are made using Density Functional Theory (DFT) with generalized gradient approximation (GGA) as exchange correlation. As a result of calculations, it has been determined that Li atom affects electronic properties of ZGNR structure significantly. It is observed that ZGNR structure exhibiting metallic behavior in pure state shows half-metal and semiconductor behavior with Li atom. © 2016 Elsevier B.V

    Effect of substitutional As impurity on electrical and optical properties of β-Si3N4 structure

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    β-Si3N4 is used as the gate dielectric for surface passivation in GaN-based, high-electron mobility transistors(HEMTs). In this study, the electrical and optical characteristics of the hexagonal β-Si3N4 crystal structure were calculated using density functional theory (DFT) and local-density approximation (LDA). Calculations of the electronic band structure and the density of states (DOS) were made for the pure β-Si3N4 crystal structure and the β-Si3N4 crystal doped with an arsenic (As) impurity atom. In addition, the optical properties such as the static dielectric constant, refractive index, extinction coefficient, absorption coefficient and reflection coefficient were examined depending on the photon energy. As a result of these calculations, it was observed that the As impurity atom drastically changed the electrical and optical properties of the pure β-Si3N4 crystalline structure, and improvements are suggested for potential further studies. © 2016 Elsevier Ltd. All rights reserved
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