37,073 research outputs found

    Calculation of Finite Size Effects on the Nucleon Mass in Unquenched QCD using Chiral Perturbation Theory

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    The finite size effects on nucleon masses are calculated in relativistic chiral perturbation theory. Results are compared with two-flavor lattice results.Comment: talk at Confinement03, 5 pages latex, 3 figures. Assignment of 2 data points to incorrect data sets in plot 1 and of 1 data point in plot 2 corrected. 1 fm lattice result updated. Conclusions unchange

    Perturbative renormalization factors in domain-wall QCD with improved gauge actions

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    We evaluate renormalization factors of the domain-wall fermion system with various improved gauge actions at one loop level. The renormalization factors are calculated for quark wave function, quark mass, bilinear quark operators, three- and four-quark operators in modified minimal subtraction (MS-bar) scheme with the dimensional reduction(DRED) as well as the naive dimensional regularization(NDR). We also present detailed results in the mean field improved perturbation theory.Comment: 44 page

    Integrated nonlinear structural simulation of composite buildings in fire

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    The collapse of several tall composite buildings over the last two decades has shown that the performance of tall, composite and complex buildings in fire is a necessary design consideration that ought to go beyond simple code compliance. To this end, several advancements in the field of numerical simulation of both the fire and the thermomechanical response of structures have been made. In isolation, the practical benefit of these advancements is limited, and their true potential is only unlocked when the results of those numerical simulations are integrated. This paper starts by showcasing recent developments in the thermal and thermomechanical analysis of structures using OpenSees. Integration of these developments into a unified simulation environment combining fire simulation, heat transfer, and mechanical analysis is then introduced. Finally, a demonstration example based on the large compartment Cardington test is used to showcase the necessity and efficiency of the developed simulation environment for thermomechanical simulation of composite structures in fire

    Nucleon matrix elements and baryon masses in the Dirac orbital model

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    Using the expansion of the baryon wave function in a series of products of single quark bispinors (Dirac orbitals), the nonsinglet axial and tensor charges of a nucleon are calculated. The leading term yields gA=1.27g_A = 1.27 in good agreement with experiment. Calculation is essentially parameter-free and depends only on the strong coupling constant value αs\alpha_s. The importance of lower Dirac bispinor component, yielding 18% to the wave function normalization is stressed. As a check, the baryon decuplet masses in the formalism of this model are also computed using standard values of the string tension σ\sigma and the strange quark mass msm_s; the results being in a good agreement with experiment.Comment: 8 pages, 2 tables; LaTeX2

    Radiative corrections to deep-inelastic eded- scattering. Case of tensor polarized deuteron

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    The model-independent radiative corrections to deep-inelastic scattering of unpolarized electron beam off the tensor polarized deuteron target have been considered. The contribution to the radiative corrections due to the hard-photon emission from the elastic electron-deuteron scattering (the so-called elastic radiative tail) is also investigated. The calculation is based on the covariant parametrization of the deuteron quadrupole polarization tensor. The numerical estimates of the radiative corrections to the polarization observables have been done for the kinematical conditions of the current experiment at HERAComment: 21 pages, 5 figure

    Temperature Dependent Viscosity of a Third Order Thin Film Fluid Layer on a Lubricating Vertical Belt

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    This paper aims to study the influence of heat transfer on thin film flow of a reactive third order fluid with variable viscosity and slip boundary condition. The problem is formulated in the form of coupled nonlinear equations governing the flow together with appropriate boundary conditions. Approximate analytical solutions for velocity and temperature are obtained using Adomian Decomposition Method (ADM). Such solutions are also obtained by using Optimal Homotopy Asymptotic Method (OHAM) and are compared with ADM solutions. Both of these solutions are found identical as shown in graphs and tables. The graphical results for embedded flow parameters are also shown

    A Review and Comparative Study of Firefly Algorithm and its Modified Versions

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    Firefly algorithm is one of the well-known swarm-based algorithms which gained popularity within a short time and has different applications. It is easy to understand and implement. The existing studies show that it is prone to premature convergence and suggest the relaxation of having constant parameters. To boost the performance of the algorithm, different modifications are done by several researchers. In this chapter, we will review these modifications done on the standard firefly algorithm based on parameter modification, modified search strategy and change the solution space to make the search easy using different probability distributions. The modifications are done for continuous as well as non-continuous problems. Different studies including hybridization of firefly algorithm with other algorithms, extended firefly algorithm for multiobjective as well as multilevel optimization problems, for dynamic problems, constraint handling and convergence study will also be briefly reviewed. A simulation-based comparison will also be provided to analyse the performance of the standard as well as the modified versions of the algorithm

    Non-compact Lattice QED with Two Charges: Phase Diagram and Renormalization Group Flow

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    The phase diagram of non-compact lattice QED in four dimensions with staggered fermions of charges 1 and 1/2-1/2 is investigated. The renormalized charges are determined and found to be in agreement with perturbation theory. This is an indication that there is no continuum limit with non-vanishing renormalized gauge coupling, and that the theory has a validity bound for every finite value of the renormalized coupling. The renormalization group flow of the charges is investigated and an estimate for the validity bound as a function of the cut-off is obtained. Generalizing this estimate to all fermions in the Standard Model,it is found that a cut-off at the Planck scale implies that αR\alpha_R has to be less than 1/801/80. Due to spontaneous chiral symmetry breaking, strongly bound fermion-antifermion composite states are generated. Their spectrum is discussed.Comment: 35 pages, LATEX, 26 PostScript figures (uuencoded

    SWI/SNF regulates a transcriptional programme that induces senescence to prevent liver cancer

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    Oncogene-induced senescence (OIS) is a potent tumour suppressor mechanism. To identify senescence regulators relevant to cancer, we screened an shRNA library targeting genes deleted in hepatocellular carcinoma (HCC). Here, we describe how knockdown of the SWI/SNF component ARID1B prevents OIS and cooperates with RAS to induce liver tumours. ARID1B controls p16INK4a and p21CIP1a transcription but also regulates DNA damage, oxidative stress and p53 induction, suggesting that SWI/SNF uses additional mechanisms to regulate senescence. To systematically identify SWI/SNF targets regulating senescence, we carried out a focused shRNA screen. We discovered several new senescence regulators including ENTPD7, an enzyme that hydrolyses nucleotides. ENTPD7 affects oxidative stress, DNA damage and senescence. Importantly, expression of ENTPD7 or inhibition of nucleotide synthesis in ARID1B-depleted cells results in re-establishment of senescence. Our results identify novel mechanisms by which epigenetic regulators can affect tumor progression and suggest that pro-senescence therapies could be employed against SWI/SNF-mutated cancers
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