12,174 research outputs found

    Bs Mixing, DeltaGamma_s and CP Violation

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    We discuss the results from the Tevatron experiments on mixing and {\sf CP} violation in the BsBˉs0B_s-\bar{B}_s^0 system, with particular emphasis to the first measurements of the decay width-difference ΔΓs\Delta\Gamma_s and the {\sf CP} violating phase βs\beta_s using flavor tagging information. We also briefly review the charge asymmetry measurements in semileptonic BsB_s decays and in B±J/ψK±B^\pm \to J/\psi K^\pm decays.Comment: 6 pages, 4 figures, Pub. Proceedings of the XLIIIrd Rencontres de Moriond on Electroweak Interactions and Unified Theories, La Thuile, Italy, March 1-8, 200

    Electronic viscosity in a quantum well: A test for the local density approximation

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    In the local density approximation (LDA) for electronic time-dependent current-density functional theory (TDCDFT) many-body effects are described in terms of the visco-elastic constants of the homogeneous three-dimensional electron gas. In this paper we critically examine the applicability of the three-dimensional LDA to the calculation of the viscous damping of 1-dimensional collective oscillations of angular frequency ω\omega in a quasi 2-dimensional quantum well. We calculate the effective viscosity ζ(ω)\zeta(\omega) from perturbation theory in the screened Coulomb interaction and compare it with the commonly used three-dimensional LDA viscosity Y(ω)Y(\omega). Significant differences are found. At low frequency Y(ω)Y(\omega) is dominated by a shear term, which is absent in ζ(ω)\zeta(\omega). At high frequency ζ(ω)\zeta(\omega) and Y(ω)Y(\omega) exhibit different power law behaviors (ω3\omega^{-3} and ω5/2\omega^{-5/2} respectively), reflecting different spectral densities of electron-hole excitations in two and three dimensions. These findings demonstrate the need for better approximations for the exchange-correlation stress tensor in specific systems where the use of the three-dimensional functionals may lead to unphysical results.Comment: 10 pages, 7 figures, RevTex

    Genomic and structural investigation on dolphin morbillivirus (DMV) in Mediterranean fin whales (Balaenoptera physalus).

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    Dolphin morbillivirus (DMV) has been deemed as one of the most relevant threats for fin whales (Balaenoptera physalus) being responsible for a mortality outbreak in the Mediterranean Sea in the last years. Knowledge of the complete viral genome is essential to understand any structural changes that could modify virus pathogenesis and viral tissue tropism. We report the complete DMV sequence of N, P/V/C, M, F and H genes identified from a fin whale and the comparison of primary to quaternary structure of proteins between this fin whale strain and some of those isolated during the 1990-'92 and the 2006-'08 epidemics. Some relevant substitutions were detected, particularly Asn52Ser located on F protein and Ile21Thr on N protein. Comparing mutations found in the fin whale DMV with those occurring in viral strains of other cetacean species, some of them were proven to be the result of diversifying selection, thus allowing to speculate on their role in host adaptation and on the way they could affect the interaction between the viral attachment and fusion with the target host cells

    A simple framework for investigating the properties of policy games

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    The paper extensively studies the static model of non-cooperative linear quadratic games in which a set of agents chooses their instruments strategically to minimize their linear quadratic criterion. We first derive the necessary and sufficient conditions for the existence of a Nash equilibrium as well as for multiple equilibria to arise. Furthermore, we study the general condition for policy neutrality and Pareto efficiency of the equilibrium by introducing a new concept of decisiveness.Conflict of interest, Nash equilibrium existence, multiplicity, policy invariance, controllability, Pareto efficiency

    Viscous corrections to the resistance of nano-junctions: a dispersion relation approach

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    It is well known that the viscosity of a homogeneous electron liquid diverges in the limits of zero frequency and zero temperature. A nanojunction breaks translational invariance and necessarily cuts off this divergence. However, the estimate of the ensuing viscosity is far from trivial. Here, we propose an approach based on a Kramers-Kr\"onig dispersion relation, which connects the zero-frequency viscosity, η(0)\eta(0), to the high-frequency shear modulus, μ\mu_{\infty}, of the electron liquid via η(0)=μτ\eta(0) =\mu_{\infty} \tau, with τ\tau the junction-specific momentum relaxation time. By making use of a simple formula derived from time-dependent current-density functional theory we then estimate the many-body contributions to the resistance for an integrable junction potential and find that these viscous effects may be much larger than previously suggested for junctions of low conductance.Comment: 6 pages, 5 figures, Revised versio

    Spot size measurements in the Eli-NP compton gamma source

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    A high brightness electron Linac is being built in the Compton Gamma Source at the ELI Nuclear Physics facility in Romania. To achieve the design luminosity, a train of 32 bunches with a nominal charge of 250 pC and 16 ns spacing , will collide with the laser beam in the interaction point. Electron beam spot size is measured with an OTR (optical transition radiation) profile moni-tors. In order to measure the beam properties, the optical radiation detecting system must have the necessary accu-racy and resolution. This paper deals with the studies of different optic configurations to achieve the magnifica-tion, resolution and accuracy desired considering design and technological constraints; we will compare several configurations of the optical detection line to justify the one chosen for the implementation in the Lina

    Experimental Test of Two-way Quantum Key Distribution in Presence of Controlled Noise

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    We describe the experimental test of a quantum key distribution performed with a two-way protocol without using entanglement. An individual incoherent eavesdropping is simulated and induces a variable amount of noise on the communication channel. This allows a direct verification of the agreement between theory and practice.Comment: 4 pages, 3 figure

    L’utilizzo delle protesi endoscopiche nella patologia dell’apparato digerente

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    L’utilizzo di protesi ad introduzione per via endoscopica per patologie dell’apparato digerente sia benigne che maligne ha avuto negli ultimi anni un considerevole sviluppo. Il posizionamento delle endoprotesi è ben tollerato dai pazienti, non necessita di anestesia e comporta rischi relativamente minimi. Le nuove protesi metalliche autoespansibili permettono di risolvere stenosi anche molto serrate senza quasi mai necessità di dilatazione, con riduzione dei rischi che da questa derivano. Viene riportata una revisione dell’esperienza di protesizzazione per patologie dell’apparato digerente e vengono discussi le indicazioni, i limiti e le complicanze, sulla scorta dei dati dalla letteratura internazionale

    Colecistectomia laparoscopica in situs viscerum inversus totalis: nota di tecnica

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    The Authors report the case of a patient admitted in Emergency Room for biliary colic. She knew her dextrocardia. ECG and chest X-ray confirmed the dextrocardia. Ultrasonography and CT scan discovered a situs viscerum inversus totalis and cholecystolithiasis responsible of the abdominal colic. Laparoscopic cholecystectomy was performed. The Authors discuss the clinical case and the particular technique used

    Bacterial Source Tracking to Support the Development and Implementation of Watershed Protection Plans for the Lampasas and Leon Rivers: Lampasas River Watershed Final Report

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    The Bacterial Source Tracking to Support the Development and Implementation of Watershed Protection Plans for the Lampasas and Leon Rivers project was developed to provide supplemental information to stakeholders engaged in the development and implementation of watershed protection plans for each watershed. The Leon River is listed as an impaired water body for elevated levels of E. coli and does not support its designated contact recreation use. The Lampasas River was also considered impaired for elevated E. coli levels until 2010 when it was determined that the data listing the segment no longer met the state’s criteria for assessment. Through the watershed protection planning process, stakeholders in each watershed will use adaptive management to refine management strategies that will mitigate bacteria loading from potential sources of pollution within the watershed
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