60 research outputs found

    η\eta Production in Peripheral Heavy-Ion Collisions

    Full text link
    We estimate the impact parameter dependence of the production cross section for ηc\eta_c and ηb\eta_b mesons in peripheral heavy-ion collisions collisions. Total and elastic γγ\gamma\gamma cross sections are calculated in an equivalent photon approximation.Comment: 9 pages, uuencoded postscrip

    Two-photon final states in peripheral heavy ion collisions

    Get PDF
    We discuss processes leading to two photon final states in peripheral heavy ion collisions at RHIC. Due to the large photon luminosity we show that the continuum subprocess γγ→γγ\gamma \gamma \to \gamma \gamma can be observed with a large number of events. We study this reaction when it is intermediated by a resonance made of quarks or gluons and discuss its interplay with the continuum process, verifying that in several cases the resonant process ovewhelms the continuum one. It is also investigated the possibility of observing a scalar resonance (the σ\sigma meson) in this process. Assuming for the σ\sigma the mass and total decay width values recently reported by the E791 Collaboration we show that RHIC may detect this particle in its two photon decay mode if its partial photonic decay width is of the order of the ones discussed in the literature.Comment: 10 pages, 8 figure

    Photon-Photon and Pomeron-Pomeron Processes in Peripheral Heavy Ion Collisions

    Get PDF
    We estimate the cross sections for the production of resonances, pion pairs and a central cluster of hadrons in peripheral heavy-ion collisions through two-photon and double-pomeron exchange, at energies that will be available at RHIC and LHC. The effect of the impact parameter in the diffractive reactions is introduced, and imposing the condition for realistic peripheral collisions we verify that in the case of very heavy ions the pomeron-pomeron contribution is indeed smaller than the electromagnetic one. However, they give a non-negligible background in the collision of light ions. This diffractive background will be more important at RHIC than at LHC.Comment: 22 pages, 1 Postscript figures, 4 tables, to appear in Phys. Rev.

    Matrix metalloproteinases and tissue inhibitors of metalloproteinases in extracellular matrix remodeling during left ventricular diastolic dysfunction and heart failure with preserved ejection fraction: A systematic review and meta-analysis

    Get PDF
    Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) are pivotal regulators of extracellular matrix (ECM) composition and could, due to their dynamic activity, function as prognostic tools for fibrosis and cardiac function in left ventricular diastolic dysfunction (LVDD) and heart failure with preserved ejection fraction (HFpEF). We conducted a systematic review on experimental animal models of LVDD and HFpEF published in MEDLINE or Embase. Twenty-three studies were included with a total of 36 comparisons that reported established LVDD, quantification of cardiac fibrosis and cardiac MMP or TIMP expression or activity. LVDD/HFpEF models were divided based on underlying pathology: hemodynamic overload (17 comparisons), metabolic alteration (16 comparisons) or ageing (3 comparisons). Meta-analysis showed that echocardiographic parameters were not consistently altered in LVDD/HFpEF with invasive hemodynamic measurements better representing LVDD. Increased myocardial fibrotic area indicated comparable characteristics between hemodynamic and metabolic models. Regarding MMPs and TIMPs; MMP2 and MMP9 activity and protein and TIMP1 protein levels were mainly enhanced in hemodynamic models. In most cases only mRNA was assessed and there were no correlations between cardiac tissue and plasma levels. Female gender, a known risk factor for LVDD and HFpEF, was underrepresented. Novel studies should detail relevant model characteristics and focus on MMP and TIMP protein expression and activity to identify predictive circulating markers in cardiac ECM remodeling

    Measurement-based quantum foundations

    Full text link
    I show that quantum theory is the only probabilistic framework that permits arbitrary processes to be emulated by sequences of local measurements. This supports the view that, contrary to conventional wisdom, measurement should not be regarded as a complex phenomenon in need of a dynamical explanation but rather as a primitive -- and perhaps the only primitive -- operation of the theory.Comment: 8 pages, version to appear in Found. Phy

    EMIL The energy materials in situ laboratory Berlin a novel characterization facility for photovoltaic and energy materials

    Get PDF
    A knowledge based approach towards developing a new generation of solar energy conversion devices requires a fast and direct feedback between sophisticated analytics and state of the art processing test facilities for all relevant material classes. A promising approach is the coupling of synchrotron based X ray characterization techniques, providing the unique possibility to map the electronic and chemical structure of thin layers and interface regions with relevant in system in situ sample preparation or in operando analysis capabilities in one dedicated laboratory. EMIL, the Energy Materials In situ Laboratory Berlin, is a unique facility at the BESSY II synchrotron light source. EMIL will be dedicated to the in system, in situ, and in operando X ray analysis of materials and devices for energy conversion and energy storage technologies including photovoltaic applications and photo electrochemical processes. EMIL comprises up to five experimental end stations, three of them can access X rays in an energy range of 80 eV 10 keV. For example, one key setup of EMIL combines a suite of advanced spectroscopic characterization tools with industry relevant deposition facilities in one integrated ultra high vacuum system. These deposition tools allow the growth of PV devices based on silicon, compound semiconductors, hybrid heterojunctions, and organo metal halide perovskites on up to 6 sized substrates. EMIL will serve as a research platform for national and international collaboration in the field of photovoltaic photocatalytic energy conversion and beyond. In this paper, we will provide an overview of the analytic and material capabilities at EMIL

    Rare coding variants in genes encoding GABA(A) receptors in genetic generalised epilepsies : an exome-based case-control study

    Get PDF
    Background Genetic generalised epilepsy is the most common type of inherited epilepsy. Despite a high concordance rate of 80% in monozygotic twins, the genetic background is still poorly understood. We aimed to investigate the burden of rare genetic variants in genetic generalised epilepsy. Methods For this exome-based case-control study, we used three different genetic generalised epilepsy case cohorts and three independent control cohorts, all of European descent. Cases included in the study were clinically evaluated for genetic generalised epilepsy. Whole-exome sequencing was done for the discovery case cohort, a validation case cohort, and two independent control cohorts. The replication case cohort underwent targeted next-generation sequencing of the 19 known genes encoding subunits of GABA(A) receptors and was compared to the respective GABA(A) receptor variants of a third independent control cohort. Functional investigations were done with automated two-microelectrode voltage clamping in Xenopus laevis oocytes. Findings Statistical comparison of 152 familial index cases with genetic generalised epilepsy in the discovery cohort to 549 ethnically matched controls suggested an enrichment of rare missense (Nonsyn) variants in the ensemble of 19 genes encoding GABA(A) receptors in cases (odds ratio [OR] 2.40 [95% CI 1.41-4.10]; p(Nonsyn)=0.0014, adjusted p(Nonsyn)=0.019). Enrichment for these genes was validated in a whole-exome sequencing cohort of 357 sporadic and familial genetic generalised epilepsy cases and 1485 independent controls (OR 1.46 [95% CI 1.05-2.03]; p(Nonsyn)=0.0081, adjusted p(Nonsyn)=0.016). Comparison of genes encoding GABA(A) receptors in the independent replication cohort of 583 familial and sporadic genetic generalised epilepsy index cases, based on candidate-gene panel sequencing, with a third independent control cohort of 635 controls confirmed the overall enrichment of rare missense variants for 15 GABA(A) receptor genes in cases compared with controls (OR 1.46 [95% CI 1.02-2.08]; p(Nonsyn)=0.013, adjusted p(Nonsyn)=0.027). Functional studies for two selected genes (GABRB2 and GABRA5) showed significant loss-of-function effects with reduced current amplitudes in four of seven tested variants compared with wild-type receptors. Interpretation Functionally relevant variants in genes encoding GABA(A) receptor subunits constitute a significant risk factor for genetic generalised epilepsy. Examination of the role of specific gene groups and pathways can disentangle the complex genetic architecture of genetic generalised epilepsy. Copyright (C) 2018 The Author(s). Published by Elsevier Ltd.Peer reviewe

    Refined histopathological predictors of BRCA1 and BRCA2 mutation status: A large-scale analysis of breast cancer characteristics from the BCAC, CIMBA, and ENIGMA consortia

    Get PDF
    Introduction: The distribution of histopathological features of invasive breast tumors in BRCA1 or BRCA2 germline mutation carriers differs from that of individuals with no known mutation. Histopathological features thus have utility for mutation prediction, including statistical modeling to assess pathogenicity of BRCA1 or BRCA2 variants of uncertain clinical significance. We analyzed large pathology datasets accrued by the Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA) and the Breast Cancer Association Consortium (BCAC) to reassess histopathological predictors of BRCA1 and BRCA2 mutation status, and provide robust likelihood ratio (LR) estimates for statistical modeling. Methods: Selection criteria for study/center inclusion were estrogen receptor (ER) status or grade data available for invasive breast cancer diagnosed younger than 70 years. The dataset included 4,477 BRCA1 mutation carriers, 2,565 BRCA2 mutation carriers, and 47,565 BCAC breast cancer cases. Country-stratified estimates of the
    • 

    corecore