3,620 research outputs found

    Vibron transport in macromolecular chains

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    We study the hopping mechanism of the vibron excitation transport in the simple 1D model of biological macromolecular chains. We supposed that the vibron interaction with thermal oscillations of the macromolecular structural elements will result in vibron self -trapping, and the formation of the partial dressed vibron state. With use of the modified Holstein polaron model, we calculate vibron diffusivity in dependence of the basic system parameters and temperature. We obtain that the vibron diffusivity smoothly decreases in non adiabatic limit when the strength of the vibron-phonon coupling grows. However this dependence becomes by discontinuous one in case of growth of the adiabaticity of the system. The value of the critical point depends of the system temperature, and at room temperatures it belongs to the low or intermediate coupling regime. We discuss an application of these results to study of vibron transport to 3D bundles of such macromolecules chains considering it as polymer nanorods and to 2D polymer films organized from such macromolecules.Comment: 4 pages, 6 figures, contribution to the Proceedings of the Conference "Physical mesomechanics of multi-level systems`2014", September 3-5 2014, Tomsk, Russi

    Chizhov and Petcov Reply

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    We have found in [1] new conditions for a total neutrino conversion in the case of neutrino oscillations taking place in a medium, consisting of n = 2 (or 3) alternating layers with constant densities N1N_1 and N2N_2. It is claimed in [4] that our results are particular case of enhancement of neutrino oscillations, which was suggested earlier by other authors and was widely discussed in the literature. We refute these claims, confirming the novelty of our results.Comment: 2 pages, LATEX; concise (essentially 1 page) and somewhat modified version of Ref. SISSA 5/2000/EP (hep-ph/0003110); reply on the ``Comment on New Conditions for a Total Neutrino Conversion in a Medium'', Phys. Rev. Lett. 85 (2000) 3978; published as ``Chizhov and Petcov Reply'' in Phys. Rev. Lett. 85 (2000) 397

    Charged-Lepton-Flavour Violation in Kaon Decays in Supersymmetric Theories

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    We discuss rare kaon decays that violate charged-lepton flavour conservation in supersymmetric theories with and without R parity, in view of possible experiments using an intense proton source as envisaged for a neutrino factory. In the Minimal Supersymmetric Standard Model, such decays are generated by box diagrams involving charginos and neutralinos, but the limits from \mu -> e \gamma, \mu-e conversion and \Delta m_K constrain the branching ratios to challengingly small values. However, this is no longer the case in R-violating theories, where such decays may occur at tree level at rates close to the present experimental limits. Within this framework, we obtain bounds on products of LL\bar{E} and LQ\bar{D} operators from the experimental upper limits on K^0 -> \mu^\pm e^\mp and K^{\pm,0} -> \pi^{\pm,0} \mu^\pm e^\mp decays. We also note the possibility of like-sign lepton decays K^\pm -> \pi^\mp \ell^\pm \ell^\pm in the presence of non-zero \tilde{b}_L-\tilde{b}_R mixing. We conclude that rare kaon decays violating charged-lepton flavour conservation could be an interesting signature of R violation.Comment: 25 pages, 6 figures, Prepared for the Kaon Physics Working Group as part of the ECFA/CERN study of Neutrino Factory & Muon Storage Rings At CERN. Referencies added, constraints update

    A Review of Rare Pion and Muon Decays

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    After a decade of no measurements of pion and muon rare decays, PIBETA, a new experimental program is producing its first results. We report on a new experimental study of the pion beta decay, Pi(+) -> Pi(0) e(+) Nu, the Pi(e2 gamma) radiative decay, Pi(+) -> e(+) Nu Gamma, and muon radiative decay, Mu -> e Nu Gamma. The new results represent four- to six-fold improvements in precision over the previous measurements. Excellent agreement with Standard Model predictions is observed in all channels except for one kinematic region of the Pi(e2 gamma) radiative decay involving energetic photons and lower-energy positrons.Comment: 10 pages, 6 figures, 2 tables, invited talk presented at MESON 2004, 8th Int'l. Workshop on Meson Production, Properties and Interaction, Krakow, Poland 4-8 June 200

    Conductance-Based Refractory Density Approach for a Population of Bursting Neurons

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    The conductance-based refractory density (CBRD) approach is a parsimonious mathematical-computational framework for modeling interact- ing populations of regular spiking neurons, which, however, has not been yet extended for a population of bursting neurons. The canonical CBRD method allows to describe the firing activity of a statistical ensemble of uncoupled Hodgkin-Huxley-like neurons (differentiated by noise) and has demonstrated its validity against experimental data. The present manuscript generalises the CBRD for a population of bursting neurons; however, in this pilot computational study we consider the simplest setting in which each individual neuron is governed by a piecewise linear bursting dynamics. The resulting popula- tion model makes use of slow-fast analysis, which leads to a novel method- ology that combines CBRD with the theory of multiple timescale dynamics. The main prospect is that it opens novel avenues for mathematical explo- rations, as well as, the derivation of more sophisticated population activity from Hodgkin-Huxley-like bursting neurons, which will allow to capture the activity of synchronised bursting activity in hyper-excitable brain states (e.g. onset of epilepsy).Russian Science Foundation grant (project 16-15- 10201) Spanish grant MINECO-FEDER-UE MTM-2015-71509-C2-2-R Catalan Grant number 2017SGR104

    Utilization of the wastes of vital activity

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    The recycling of wastes from the biological complex for use in life-support systems is discussed. Topics include laboratory equipment, heat treatment of waste materials, mineralization of waste products, methods for production of ammonium hydroxide and nitric acid, the extraction of sodium chloride from mineralized products, and the recovery of nutrient substances for plants from urine
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