20 research outputs found

    Single parameter scaling in 1-D localized absorbing systems

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    Numerical study of the scaling of transmission fluctuations in the 1-D localization problem in the presence of absorption is carried out. Violations of single parameter scaling for lossy systems are found and explained on the basis of a new criterion for different types of scaling behavior derived by Deych et al [Phys. Rev. Lett., {\bf 84}, 2678 (2000)].Comment: 7 pages, 6 figures, RevTex, submitted to Phys. Rev.

    Single parameter scaling in one-dimensional localization revisited

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    The variance of the Lyapunov exponent is calculated exactly in the one-dimensional Anderson model with random site energies distributed according to the Cauchy distribution. We find a new significant scaling parameter in the system, and derive an exact analytical criterion for single parameter scaling which differs from the commonly used condition of phase randomization. The results obtained are applied to the Kronig-Penney model with the potential in the form of periodically positioned δ\delta-functions with random strength.Comment: Phys. Rev. Lett. 84, 2678 (2000

    Point-Form Analysis of Elastic Deuteron Form Factors

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    Point-form relativistic quantum mechanics is applied to elastic electron-deuteron scattering. The deuteron is modeled using relativistic interactions that are scattering-equivalent to the nonrelativistic Argonne v18v_{18} and Reid '93 interactions. A point-form spectator approximation (PFSA) is introduced to define a conserved covariant current in terms of single-nucleon form factors. The PFSA is shown to provide an accurate description of data up to momentum transfers of 0.5 GeV2{\rm GeV}^2, but falls below the data at higher momentum transfers. Results are sensitive to the nucleon form factor parameterization chosen, particularly to the neutron electric form factor.Comment: RevTex, 31 pages, 1 table, 13 figure

    Poincare' Covariant Current Operator and Elastic Electron-Deuteron Scattering in the Front-form Hamiltonian Dynamics

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    The deuteron electromagnetic form factors, A(Q2)A(Q^2) and B(Q2)B(Q^2), and the tensor polarization T20(Q2)T_{20}(Q^2), are unambiguously calculated within the front-form relativistic Hamiltonian dynamics, by using a novel current, built up from one-body terms, which fulfills Poincar\'e, parity and time reversal covariance, together with Hermiticity and the continuity equation. A simultaneous description of the experimental data for the three deuteron form factors is achieved up to Q2<0.4(GeV/c)2Q^2 < 0.4 (GeV/c)^2. At higher momentum transfer, different nucleon-nucleon interactions strongly affect A(Q2)A(Q^2), B(Q2)B(Q^2), and T20(Q2)T_{20}(Q^2) and the effects of the interactions can be related to SS-state kinetic energy in the deuteron. Different nucleon form factor models have huge effects on A(Q2)A(Q^2), smaller effects on B(Q2)B(Q^2) and essentially none on T20(Q2)T_{20}(Q^2).Comment: 31 pages + 16 figures. Submitted to Phys. Rev.

    Radiative corrections to polarization observables in elastic electron-deuteron scattering in leptonic variables

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    The model--independent QED radiative corrections to polarization observables in elastic scattering of unpolarized and longitudinally--polarized electron beam by the deuteron target have been calculated in leptonic variables. The experimental setup when the deuteron target is arbitrarily polarized is considered and the procedure for applying derived results to the vector or tensor polarization of the recoil deuteron is discussed. The basis of the calculations consists of the account for all essential Feynman diagrams which results in the form of the Drell-Yan representation for the cross-section and use of the covariant parametrization of the deuteron polarization state. The numerical estimates of the radiative corrections are given for the case when event selection allows the undetected particles (photons and electron-positron pairs) and the restriction on the lost invariant mass is used.Comment: 43 pages,3 figures. To be published in ZhTEF. revised 14.02.2012. arXiv admin note: text overlap with arXiv:nucl-ex/0002003 by other author

    Quantitative analysis of ribosome–mRNA complexes at different translation stages

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    Inhibition of primer extension by ribosome–mRNA complexes (toeprinting) is a proven and powerful technique for studying mechanisms of mRNA translation. Here we have assayed an advanced toeprinting approach that employs fluorescently labeled DNA primers, followed by capillary electrophoresis utilizing standard instruments for sequencing and fragment analysis. We demonstrate that this improved technique is not merely fast and cost-effective, but also brings the primer extension inhibition method up to the next level. The electrophoretic pattern of the primer extension reaction can be characterized with a precision unattainable by the common toeprint analysis utilizing radioactive isotopes. This method allows us to detect and quantify stable ribosomal complexes at all stages of translation, including initiation, elongation and termination, generated during the complete translation process in both the in vitro reconstituted translation system and the cell lysate. We also point out the unique advantages of this new methodology, including the ability to assay sites of the ribosomal complex assembly on several mRNA species in the same reaction mixture

    The deuteron: structure and form factors

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    A brief review of the history of the discovery of the deuteron in provided. The current status of both experiment and theory for the elastic electron scattering is then presented.Comment: 80 pages, 33 figures, submited to Advances in Nuclear Physic

    The Problems of Passive Remote Sensing of the Earth’s Surface in the Range of 1.2–1.6 GHz

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    The main problems of remote sensing of the Earth&rsquo;s surface within the frequency range 1.2&ndash;1.6 GHz are discussed. They are related to the resonant quantum properties of the radio wave propagation medium in the lower ionosphere. It is shown that, for the passive remote sensing, the main source is incoherent microwave radiation of the D and E ionospheric layers in the decimeter range. For the first time, a theoretically grounded principally new scheme of measurements is suggested. The scheme assumes that the radiation source exists below the satellite orbit and accounts for the fact that two types of radiation (direct and reflected) reach the satellite sensor. The separation of the respective fluxes is a serious problem that should be solved for the correct interpretation of the measurements. The question is raised regarding the correct calibration of measuring equipment, depending on the current state of the ionosphere

    Se non potere \ue8 non volere. L\u2019evoluzione diacronica del prezens naprasnogo o\u17eidanija

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    In russo antico i significati non attuali del non-passato proto-perfettivo (NPPF), tra cui anche il cosiddetto prezens naprasnogo o\u17eidanija (PNO), avevano una maggiore distribuzione. In determinati contesti, il PNO esprimeva, oltre all\u2019\u201cimpossibilit\ue0\u201d, la \u201cnon volont\ue0\u201d di portare a termine una data azione (oggi codificata nelle costruzioni polisemantiche interrogativo-negative del tipo di Po\u10demu ty ko mne ne zajde\u161\u2019?). A partire da testi databili tra il XI e il XV secolo \u2013 la redazione Lavrent\u2019evskaja della Povest\u2019 vremennych let, le gramoty e lo \u17ditie i cho\u17edenie dell\u2019igumeno Daniil \u2013 il presente contributo intende indagare le ragioni formali di questo cambiamento intrasistema
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