8,572 research outputs found

    On the Generalised Pauli--Villars Regularization of the Standard Model

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    We show that the regularization of the Standard Model proposed by Frolov and Slavnov describes a nonlocal theory with quite simple Lagrangian.Comment: 7 pages, harvma

    Nonlocal effects in the shot noise of diffusive superconductor - normal-metal systems

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    A cross-shaped diffusive system with two superconducting and two normal electrodes is considered. A voltage eV<ΔeV < \Delta is applied between the normal leads. Even in the absence of average current through the superconducting electrodes their presence increases the shot noise at the normal electrodes and doubles it in the case of a strong coupling to the superconductors. The nonequilibrium noise at the superconducting electrodes remains finite even in the case of a vanishingly small transport current due to the absence of energy transfer into the superconductors. This noise is suppressed by electron-electron scattering at sufficiently high voltages.Comment: 4 pages, RevTeX, 2 eps figure

    Parametric investigation of nonlinear fluctuations in a dc glow discharge plasma

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    Glow discharge plasmas exhibit various types of self excited oscillations for different initial conditions like discharge voltages and filling pressures. The behavior of such oscillations associated with the anode glow have been investigated using nonlinear techniques like correlation dimension, largest Lyapunov exponent etc. It is seen that these oscillations go to an ordered state from a chaotic state with increase in input energy i.e. with discharge voltages implying occurrence of inverse bifurcations. These results are different from the other observations wherein the fluctuations have been observed to go from ordered to chaotic state.Comment: Submitted to Chao

    In silico estimates of the free energy rates in growing tumor spheroids

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    The physics of solid tumor growth can be considered at three distinct size scales: the tumor scale, the cell-extracellular matrix (ECM) scale and the sub-cellular scale. In this paper we consider the tumor scale in the interest of eventually developing a system-level understanding of the progression of cancer. At this scale, cell populations and chemical species are best treated as concentration fields that vary with time and space. The cells have chemo-mechanical interactions with each other and with the ECM, consume glucose and oxygen that are transported through the tumor, and create chemical byproducts. We present a continuum mathematical model for the biochemical dynamics and mechanics that govern tumor growth. The biochemical dynamics and mechanics also engender free energy changes that serve as universal measures for comparison of these processes. Within our mathematical framework we therefore consider the free energy inequality, which arises from the first and second laws of thermodynamics. With the model we compute preliminary estimates of the free energy rates of a growing tumor in its pre-vascular stage by using currently available data from single cells and multicellular tumor spheroids.Comment: 27 pages with 5 figures and 2 tables. Figures and tables appear at the end of the pape

    Effect of oral exposure of mycobacterium avium intracellulare on the protective imunity induced by BCG

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    The relative protective efficacy of oral administration of mycobacteria as compared to the conventional intradermal route of vaccination has been assessed in guinea pigs. Skin test reactivity to partially purified protein derivative and protective immunity to challenge with virulent Mycobacterium tuberculosis were used as parameters of protective immunity. Oral immunisation of guinea pigs either with BCG or with Mycobacterium avium intracellulare induces skin test reactivity and protective immunity comparable to that induced by intradermal route of vaccination. Oral exposure of Mycobacterium avium intracellulare prior to oral or intradermal dose of BCG did not interfere with the protective immunity induced by BCG in guinea pigs challenged with Mycobacterium tuberculosis H37Rv

    Molecular analysis of isoniazid-resistant clinical isolates of Mycobacterium tuberculosis from India

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    The presence of mutations in specific regions of katG, inhA, oxyR–ahpC and kasA associated with isoniazid (INH)-resistant clinical isolates of Mycobacterium tuberculosis from India were analysed by DNA sequencing. Point mutations in the katG gene at codon 315 and a mutation at codon 138 were detected in 64.3% (45/70) and 4% (1/25) of isolates, respectively. Polymorphisms at codon 463 of the katG gene were found both in resistant and sensitive isolates. Mutation at the inhA and oxyR–ahpC promoter regions occurred in 11.4% (8/70) and 35.0% (14/40) of the isolates, respectively. No mutation was found to occur in kasA and inhA structural gene regions. Of the 70 resistant isolates studied, 55 (78.6%) showed mutation in the regions sequenced. This is the first comprehensive molecular analysis of INH resistance in India, which suggests that point mutation rather than deletion and insertion is the major cause of INH resistance
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