5,710 research outputs found

    Comment on ``Inflation and flat directions in modular invariant superstring effective theories''

    Get PDF
    The inflation model of Gaillard, Lyth and Murayama is revisited, with a systematic scan of the parameter space for dilaton stabilization during inflation.Comment: 7 pages, 2 figure

    Three-way electrical gating characteristics of metallic Y-junction carbon nanotubes

    Get PDF
    Y-junction based carbon nanotube (CNT) transistors exhibit interesting switching behaviors, and have the structural advantage that the electrical gate for current modulation can be formed by any of the three constituent branches. In this letter, we report on the gating characteristics of metallic Y-CNT morphologies. By measuring the output conductance and transconductance we conclude that the efficiency and gain depend on the branch diameter and is electric field controlled. Based on these principles, we propose a design for a Y-junction based CNT switching device, with tunable electrical properties

    Memory disorders and vasopressin

    Get PDF

    Lepton-Flavour Violation in Ordinary and Supersymmetric Grand Unified Theories

    Get PDF
    By an explicit calculation we show that in ordinary SU(5) logarithmic divergence in the amplitude of Ό→eÎł\mu \to e\gamma cancels among diagrams and remaining finite part is suppressed by at least 1/MGUT21/M_{GUT}^2. In SUSY SU(5), when the effect of flavour changing wave function renormalization is taken into account such logarithmic correction disappears, provided a condition is met among SUSY breaking masses. In SUGRA-inspired SUSY GUT the remaining logarithmic effect is argued not to be taken as a prediction of the theory.Comment: 8 pages, LaTeX209 file, using axodraw.st

    Coronary artery disease screening in diabetic patients: how good is guideline adherence?

    Get PDF
    INTRODUCTION: Diabetic patients are at high risk for coronary artery disease (CAD), which is the leading cause of death in this population. The Swiss Society of Endocrinology-Diabetology (SSED) recommends CAD screening for diabetic patients with > or = 2 additional cardiovascular risk factors (CVRF), by stress echocardiography (SE) or myocardial perfusion imaging (MPI). The aim of this study was to assess the application of these guidelines and the treatment of CVRF in the diabetes outpatient clinics of the five Swiss University Hospitals. METHODS: The study was initiated in Lausanne and the study questionnaires were circulated to the endocrinologists of the five Swiss University Hospitals. Practitioners were asked to include consecutive patients attending the diabetes outpatient clinics over one month. Prevalence of CAD, screening methods for CAD, prevalence of CVRF, biological analyses over the last 6 months and medical therapy were recorded. RESULTS: A total of 302 subjects were included. The mean age was 53 +/- 14 years, 68% had type 2 diabetes, 27% type 1 and 5% other types. Among T2DM with > or = 2 CVRF, 45% were screened for CAD according to SSED guidelines. In T2DM 25% had blood pressure < or = 130/80 mm Hg, 15% a lipid profile within target, 23% HbA1c < or = 7.0%. Overall, 2% achieved all 3 targets. CONCLUSIONS: Only 45% of T2DM with > or = 2 CVRF were screened for CAD according to SSED guidelines and 2% of T2DM had proper control over all CVRF. Efforts are still necessary to improve CAD prevention and screening of diabetic patients in Swiss University Hospitals

    Edge Detection on Eddy Current Image to Increase Defect Characterization

    Get PDF
    As the nuclear yard ages, the control of steam generator tubes (SGT) must deal with new problems. In fact new defects appear, especially in the area of the tube sheet, of the tube support or at the U-bend area. Eddy current testing using Rotating Probe Coil (absolute mode) gives a better resolution. These measurements allow smaller defects to be detected along different orientations, especially defects along the circumference in the rolling transition. Signals collected during the exploration of the tube internal wall with this coil contain the useful information which is represented in the form of a cartography (or image) for each of the signal complex components

    Gaugino Condensation with S-Duality and Field-Theoretical Threshold Corrections

    Get PDF
    We study gaugino condensation in the presence of an intermediate mass scale in the hidden sector. S-duality is imposed as an approximate symmetry of the effective supergravity theory. Furthermore, we include in the K\"ahler potential the renormalization of the gauge coupling and the one-loop threshold corrections at the intermediate scale. It is shown that confinement is indeed achieved. Furthermore, a new running behaviour of the dilaton arises which we attribute to S-duality. We also discuss the effects of the intermediate scale, and possible phenomenological implications of this model.Comment: 19 pages, LaTeX, 3 postscript figures include

    The Holographic Dual of 2+1 Dimensional QFTs with N=1 SUSY and Massive Fundamental Flavours

    Full text link
    The Maldacena Nastase solution is generalised to include massive fundamental matter through the addition of a flavour profile. This gives a holographic dual to N=1 SYM-CS with massive fundamental matter with a singularity free IR. We study this solution in some detail confirming confinement and asymptotic freedom. A recently proposed solution generating technique is then applied which results in a new type-IIA supergravity solution. In a certain limit the geometry of this solution is asymptotically AdS_4X Y, where Y is the metric at the base of the Bryant-Salamon G_2 cone, which has topology S^3XS^3.Comment: 31 pages plus appendices, 6 figures. v3: Typos corrected, version to appear in JHE

    Non-factorizable contribution in nonleptonic weak interactions of K mesons

    Get PDF
    Two pion decays of K mesons, K_L-K_S mass difference, two photon and the Dalitz decays of K_L are studied systematically by assuming that their amplitude is given by a sum of factorizable and non-factorizable ones. The former is estimated by using a naive factorization while the latter is assumed to be dominated by dynamical contributions of various hadron states.Comment: 23 pages,1 figur

    Semileptonic Hyperon Decays and CKM Unitarity

    Full text link
    Using a technique that is not subject to first-order SU(3) symmetry breaking effects, we determine the VusV_{us} element of the CKM matrix from data on semileptonic hyperon decays. We obtain VusV_{us} =0.2250(27). This value is of similar precision to the one derived from Kl3K_{l3}, but higher and in better agreement with the unitarity requirement, ∣Vud∣2+∣Vus∣2+∣Vub∣2=1|V_{ud}|^2+|V_{us}|^2+|V_{ub}|^2=1.Comment: 3 pages, 1 tabl
    • 

    corecore