43 research outputs found

    Time-odd mean fields in the rotating frame: microscopic nature of nuclear magnetism

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    The microscopic role of nuclear magnetism in rotating frame is investigated for the first time in the framework of the cranked relativistic mean field theory. It is shown that nuclear magnetism modifies the expectation values of single-particle spin, orbital and total angular momenta along the rotational axis effectively creating additional angular momentum. This effect leads to the increase of kinematic and dynamic moments of inertia at given rotational frequency and has an impact on effective alignments.Comment: 16 pages, 4 figures, submitted to Physical Review

    K* nucleon hyperon form factors and nucleon strangeness

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    A crucial input for recent meson hyperon cloud model estimates of the nucleon matrix element of the strangeness current are the nucleon-hyperon-K* (NYK*) form factors which regularize some of the arising loops. Prompted by new and forthcoming information on these form factors from hyperon-nucleon potential models, we analyze the dependence of the loop model results for the strange-quark observables on the NYK* form factors and couplings. We find, in particular, that the now generally favored soft N-Lambda-K* form factors can reduce the magnitude of the K* contributions in such models by more than an order of magnitude, compared to previous results with hard form factors. We also discuss some general implications of our results for hadronic loop models.Comment: 9 pages, 8 figures, new co-author, discussion extended to the momentum dependence of the strange vector form factor

    Hadronization of a Quark-Gluon Plasma in the Chromodielectric Model

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    We have carried out simulations of the hadronization of a hot, ideal but effectively massive quark-gluon gas into color neutral clusters in the framework of the semi-classical SU(3) chromodielectric model. We have studied the possible quark-gluon compositions of clusters as well as the final mass distribution and spectra, aiming to obtain an insight into relations between hadronic spectral properties and the confinement mechanism in this model.Comment: 34 pages, 37 figure

    Polarization observables in the reaction NNNNΦNN \to NN \Phi

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    We study the reaction NNNNΦNN \to NN \Phi slightly above the threshold within an extended one-boson exchange model which also accounts for uuduud knock-out. It is shown that polarization observables, like the beam-target asymmetry, are sensible quantities for identifying a ssˉs \bar s admixture in the nucleon wave function on the few per cent level.Comment: 11 LaTeX pages including 4 ps figure

    The role of the pion cloud in the interpretation of the valence light-cone wavefunction of the nucleon

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    The pion cloud renormalises the light-cone wavefunction of the nucleon which is measured in hard, exclusive photon-nucleon reactions. We discuss the leading twist contributions to high-energy exclusive reactions taking into account both the pion cloud and perturbative QCD physics. The nucleon's electromagnetic form-factor at high Q2Q^2 is proportional to the bare nucleon probability ZZ and the cross-sections for hard (real at large angle or deeply virtual) Compton scattering are proportional to Z2Z^2. Our present knowledge of the pion-nucleon system is consistent with Z=0.7±0.2Z = 0.7 \pm 0.2. If we apply just perturbative QCD to extract a light-cone wavefunction directly from these hard exclusive cross-sections, then the light-cone wavefunction that we extract measures the three valence quarks partially screened by the pion cloud of the nucleon. We discuss how this pion cloud renormalisation effect might be understood at the quark level in terms of the (in-)stability of the perturbative Dirac vacuum in low energy QCD.Comment: Expanded Discussion of Phenomenology and Spin Physic

    Design and analysis of cross vaults along history

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    The history of cross vaults began almost 2,000 years ago with a widespread use during the Middle Ages and Renaissance, becoming nowadays one of the most diffused and fascinating structural typologies of the European building cultural heritage. However, conversely to the undeniable excellence achieved by the ancient masons, the structural behavior of these elements is still at the center of the scientific debate. In this regard, with the aim of reviewing the knowledge on this subject as a concise and valuable support for researchers involved in conservation of historical buildings, with a focus on design rules and structural analysis, the present study firstly introduces the cross vaults from a historical perspective, by describing the evolution of the main geometrical shapes together with basic practical rules used to size them. Then, the article deals with the subsequent advancements in structural analysis methods of vaults, until the development of modern limit analysis.This work was partially carried out under the program "Dipartimento di Protezione Civile - Consorzio RELUIS", signed on 2013-12-27.info:eu-repo/semantics/publishedVersio

    Suppression of CMV Infection with Letermovir in a Kidney Transplant Patient

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    Infection with cytomegalovirus (CMV) with resistance to ganciclovir (GCV) is a therapeutic challenge in kidney transplant patients, because standard treatment options are nephrotoxic. We report the case of a kidney transplant recipient with GCV-resistant CMV disease, in whom letermovir, a novel inhibitor of CMV packaging, was administered off-label and prevented a relapse of disease once the CMV load was decreased by cidofovir. Furthermore, we observed significant drug interactions between letermovir and tacrolimus
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