12,237 research outputs found

    Epitaxial silicon growth for solar cells

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    Growth and fabrication procedures for the baseline solar cells are described along with measured cell parameters, and the results. Reproducibility of these results was established and the direction to be taken for higher efficiency is identified

    Reweighting of the form factors in exclusive B --> X ell nu decays

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    A form factor reweighting technique has been elaborated to permit relatively easy comparisons between different form factor models applied to exclusive B --> X l nu decays. The software tool developped for this purpose is described. It can be used with any event generator, three of which were used in this work: ISGW2, PHSP and FLATQ2, a new powerful generator. The software tool allows an easy and reliable implementation of any form factor model. The tool has been fully validated with the ISGW2 form factor hypothesis. The results of our present studies indicate that the combined use of the FLATQ2 generator and the form factor reweighting tool should play a very important role in future exclusive |Vub| measurements, with largely reduced errors.Comment: accepted for publication by EPJ

    Natural entropy fluctuations discriminate similar looking electric signals emitted from systems of different dynamics

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    Complexity measures are introduced, that quantify the change of the natural entropy fluctuations at different length scales in time-series emitted from systems operating far from equilibrium. They identify impending sudden cardiac death (SD) by analyzing fifteen minutes electrocardiograms, and comparing to those of truly healthy humans (H). These measures seem to be complementary to the ones suggested recently [Phys. Rev. E {\bf 70}, 011106 (2004)] and altogether enable the classification of individuals into three categories: H, heart disease patients and SD. All the SD individuals, who exhibit critical dynamics, result in a common behavior.Comment: Published in Physical Review

    Nicotinic acetylcholine receptor: evidence for a functionally distinct receptor on human lymphocytes.

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    Prescription for antidepressant in reducing future alcohol-related readmission in patients suffering from depression and alcohol use disorder: a retrospective medical record review

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    BACKGROUND: Patients suffering from major depressive disorder are more likely to suffer from alcohol use disorder. The data is inconclusive for the effectiveness of antidepressant treatment of patients suffering from both illnesses in regards to improving sobriety and reducing alcohol-related healthcare expenses such as hospitalizations. The objective of this study is to determine if a new prescription of an antidepressant upon inpatient discharge is associated with a reduction in the number of future acute alcohol-related hospital readmissions to the same institution in patients suffering from major depressive disorder and alcohol-use disorder. METHODS: A retrospective, medical record review study was conducted at a publicly-supported hospital in Sylmar, CA. A query was performed for adult patients admitted between 1/1/2005-12/31/2013 who had ICD-9 codes for both alcohol-use disorder and depression. Index admission was the first hospitalization in which the patient was currently consuming alcohol and had depression as identified by physician documentation as a problem. Acute alcohol-related admissions were those for alcohol intoxication or withdrawal (indicating current alcohol use). Patients were excluded if they were receiving an antidepressant on index admission,old, no patient data available, or not currently consuming alcohol; 139 patients met inclusion criteria. Multivariate logistical regression analysis was performed on the primary predictive variable of discharge prescription of an antidepressant along with other independent variables for alcohol readmissions: homelessness, family history of alcohol use disorder, and smoking. RESULTS: Discharging patients with a prescription of an antidepressant was not associated with a reduction in acute alcohol-related readmission. There was no difference in acute alcohol-related readmissions between patients discharged with (44.6 %) versus without (47.0 %) a prescription for an antidepressant (p = 0.863). The median number of days between index admission and first readmission for those discharged on an antidepressant was 141 days while those who were not was 112 days (p = 0.284). CONCLUSION: Discharging patients suffering from both alcohol-use disorder and major depressive disorder with a prescription for an antidepressant is not associated with a reduction in future readmissions, nor significantly increase the number of days to readmission. The study does not support the concept of antidepressants in reducing acute alcohol-related readmissions

    Penguin decays of B mesons

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    Penguin, or loop, decays of B mesons induce effective flavor-changing neutral currents, which are forbidden at tree level in the Standard Model. These decays give special insight into the CKM matrix and are sensitive to non-standard model effects. In this review, we give a historical and theoretical introduction to penguins and a description of the various types of penguin processes: electromagnetic, electroweak, and gluonic. We review the experimental searches for penguin decays, including the measurements of the electromagnetic penguins b -> s gamma and B -> K* gamma and gluonic penguins B -> K pi, B+ -> omega K+ and B -> eta' K, and their implications for the Standard Model and New Physics. We conclude by exploring the future prospects for penguin physics.Comment: 49 pages, LATEX, 30 embedded figures, submitted to Annual Reviews of Nuclear and Particle Scienc

    Hyperactivity, impulsivity, and inattention in boys with cleft lip and palate: relationship to ventromedial prefrontal cortex morphology

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    The purpose of this study is to evaluate quantitative structural measures of the ventromedial prefrontal cortex (vmPFC) in boys with isolated clefts of the lip and/or palate (ICLP) relative to a comparison group and to associate measures of brain structure with quantitative measures of hyperactivity, impulsivity, and inattentiveness. A total of 50 boys with ICLP were compared to 60 healthy boys without clefts. Magnetic resonance imaging brain scans were used to evaluate vmPFC structure. Parents and teachers provided quantitative measures of hyperactivity, impulsivity, and inattentiveness using the Pediatric Behavior Scale. Boys with ICLP had significantly higher ratings of hyperactivity/impulsivity/inattention (HII) and significantly increased volume of the right vmPFC relative to the comparison group. There was a direct relationship between HII score and vmPFC volume in both the ICLP group and control group, but the relationship was in the opposite direction: in ICLP, the higher the vmPFC volume, the higher the HII score; for the comparison group, the lower the vmPFC volume, the greater the HII score. The vmPFC is a region of the brain that governs behaviors of hyperactivity, impulsivity and inattention (HII). In boys with ICLP, there are higher levels of HII compared to the controls and this is directly related to a significantly enlarged volume of the right vmPFC. Enlargement of this region of the brain is therefore considered to be pathological in the ICLP group and supports the notion that abnormal brain structure (from abnormal brain development) is the underlying etiology for the abnormal behaviors seen in this population

    Emergence of a Norm from Resistance: Using Simulation to Explore the Macro Implications of Social Identity Theory

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    We usually hope that social norms discourage injustice. However, we are all witnesses to harmful norms enforced by governments, such as xenophobia, which need to be contested and changed. Previous studies have concluded that it is possible to change a harmful norm through contestation by powerless actors if suitable structural conditions exist. However, these structural conditions have not been sufficiently studied and, as such, are the focus of this paper. Our paper begins with a review of well-established micro-level theories of social identity theory (SIT), recast as a set of 42 discrete theoretical statements. These statements are then re-expressed in the form of a systems-level theory of macro-changes in societal norms using the system dynamics approach. The over-time dynamic behavior simulated using this structure is compared to events in two well-known case studies of changes in societal norms: women’s suffrage between 1830 and 1920, and the emergence of more tolerant lesbian, gay, bisexual, transgender, and queer/questioning (LGBTQ) norms in the US between 1950 and 2018. Further simulations of the model explore the roles of anger and social outrage, foreshadowing the ability of simulation-based experiments, such as the one presented here, to explore in a robust way a wide range of (undemocratic) regimes under counter-factual conditions

    Violations of Local Duality in the Heavy Quark Sector

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    We examine the origin of possible failures of the quark-hadron local duality. In particular, we consider a correlator of two currents comprising heavy quark operators, and compare the evaluation by the Operator Product Expansion with the result obtained inserting an infinite set of hadronic states, in the N_c to infinity limit. Whereas the smeared spectral functions agree with each other, their local behaviour is different. The difference manifests itself in the form of a term O(Lambda/epsilon) (epsilon being the residual energy) that is not present in the expansion in powers of Lambda/epsilon predicted by the OPE.Comment: Latex, 14 pages, 1 figur

    Measurement of the Branching Fractions for D^0 → π^-e^+v_e and D^0 → + K^-e^+V_e and Determination of │V_(cd)/V_(cs)│^2

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    Measurements of the exclusive branching fractions B(D^0→π^-e^+ν_e) and B(D^0→K^-e^+ν_e), using data collected at the ψ(3770) with the Mark III detector at the SLAC e^+e^- storage ring SPEAR, are used to determine the ratio of the Kobayashi-Maskawa matrix elements │V_(cd)/V_(cs)│^2 =0.057_(-0.015)^(+0.038)±0.005
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