1,092 research outputs found

    A model-independent analysis of final-state interactions in \bar B_{d/s}^0 --> J/psi pi pi

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    Exploiting BB-meson decays for Standard Model tests and beyond requires a precise understanding of the strong final-state interactions that can be provided model-independently by means of dispersion theory. This formalism allows one to deduce the universal pion-pion final-state interactions from the accurately known ππ\pi\pi phase shifts and, in the scalar sector, a coupled-channel treatment with the kaon-antikaon system. In this work an analysis of the decays Bˉd0J/ψπ+π\bar B_d^0 \to J/\psi \pi^+\pi^- and Bˉs0J/ψπ+π\bar B_s^0 \to J/\psi \pi^+\pi^- is presented. We find very good agreement with the data up to 1.05 GeV with a number of parameters reduced significantly compared to a phenomenological analysis. In addition, the phases of the amplitudes are correct by construction, a crucial feature when it comes to studies of CPCP violation in heavy-meson decays.Comment: 25 pages, 6 figures, version published in JHE

    The Labors, Infrastructures and Plastics of Mumbai\u27s Waste Flows

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    This thesis attends to some of the diverse flows of various plastic post-discard in Mumbai, India. I examine the material and imagined geographies of plastic discard and collection; the labors through which these different kinds of plastics move; and the infrastructures, spaces and relations that shape the rhythms and subjectivities of waste discard and work. I think with these flows alongside concern for marine plastic pollution and within the context of rising seas in particular. I show, for example, how the existence of marine plastic is not just the result of intentional disposal into waterways because of infrastructural exclusions, but that the very practices of waste collection and disposal are not designed to accommodate unstable grounds and matter in assemblages that produce “flood” vulnerability. At the same time, these dynamic infrastructural ecologies of waste and water create expanding and shifting spaces for plastic collection. I also consider how efforts to circulate “low-value plastics” which often enter the sea might shift the infrastructures and organization of waste collection and work. Together, this thesis hopes to raise questions of how different relations to water and of wasting might be considered in relation and obligation to the lives that plastic and waste helps sustain and with consideration to ongoing forms of vulnerability and inequality

    Rate dependent shear bands in a shear transformation zone model of amorphous solids

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    We use Shear Transformation Zone (STZ) theory to develop a deformation map for amorphous solids as a function of the imposed shear rate and initial material preparation. The STZ formulation incorporates recent simulation results [Haxton and Liu, PRL 99 195701 (2007)] showing that the steady state effective temperature is rate dependent. The resulting model predicts a wide range of deformation behavior as a function of the initial conditions, including homogeneous deformation, broad shear bands, extremely thin shear bands, and the onset of material failure. In particular, the STZ model predicts homogeneous deformation for shorter quench times and lower strain rates, and inhomogeneous deformation for longer quench times and higher strain rates. The location of the transition between homogeneous and inhomogeneous flow on the deformation map is determined in part by the steady state effective temperature, which is likely material dependent. This model also suggests that material failure occurs due to a runaway feedback between shear heating and the local disorder, and provides an explanation for the thickness of shear bands near the onset of material failure. We find that this model, which resolves dynamics within a sheared material interface, predicts that the stress weakens with strain much more rapidly than a similar model which uses a single state variable to specify internal dynamics on the interface.Comment: 10 pages, 13 figures, corrected typos, added section on rate strengthening vs. rate weakening material

    Application of quantum-chemical methods including density functional theory for the interpretation of isotropic hyperfine data. The example of azulenebenzoquinone

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    The radical anion of aceneazulenedione in which a benzoquinone is fused to an azulene moiety was generated by electrolysis and by reduction with the alkali metals in ethereal solvents. The hyperfine data could not be reproduced by standard Hückel calculations which usually give reliable predictions for the spin distribution in radical ions such as azulene quinones and a variety of extended π systems. However, PPP and, preferably,ab initio geometry optimisations followed by single-point calculations of the Fermi contact interaction with density functional theory, led to a straightforward assignment of the hyperfine coupling constant

    En sammenligning af atomkraftværkers og fossile kraftværkers økonomi under danske forhold

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    Outbreak of acute hepatitis C following the use of anti-hepatitis C virus--screened intravenous immunoglobulin therapy

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    BACKGROUND and AIMS: Hepatitis C virus (HCV) infection has been associated with intravenous (IV) immunoglobulin (Ig), and plasma donations used to prepare IV Ig are now screened to prevent transmission. Thirty-six patients from the United Kingdom received infusions from a batch of anti-HCV antibody-screened intravenous Ig (Gammagard; Baxter Healthcare Ltd., Thetford, Norfolk, England) that was associated with reports of acute hepatitis C outbreak in Europe. The aim of this study was to document the epidemiology of this outbreak. METHODS: Forty-six patients from the United Kingdom treated with Gammagard (34 exposed and 12 unexposed to the batch) returned epidemiological questionnaires. RESULTS: Eighty-two percent of the exposed patients (28 of 34) became positive for HCV RNA. Eighteen percent of the patients (6 of 34) who had infusions with this batch tested negative for HCV RNA, but 2 of the patients had abnormal liver function and subsequently seroconverted to anti-HCV antibody positive. Twenty-seven percent of the patients (9 of 34) developed jaundice, and 79% (27 of 34) had abnormal liver transferase levels. Virus isolates (n=21), including an isolate from the implicated batch, were genotype 1a and virtually identical by sequence analysis of the NS5 region, consistent with transmission from a single source. CONCLUSIONS: Hepatitis C infection can be transmitted by anti-HCV-screened IV Ig. Careful documentation of IV Ig batch numbers and regular biochemical monitoring is recommended for all IV Ig recipients

    Logistics support requirements: a case analysis of the Tactical Quiet Generator

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    Recent trends in technological advances have resulted in the commercial sector leading the military sector in many areas of technological development. As a result, there are many readily available components and end items that can be designed, integrated and assembled into military hardware that will satisfy the stringent requirements of the tactical battlefield. Use of commercial or non. developmental items compresses the overall acquisition time, but currently reduces time available for logistics planning and preparation. The result is new systems being fielded without the necessary support structure in place. Proper use of warranties, Contractor Logistics Support, and Prime Vendor support might improve equipment readiness and ensure the gap is bridged between a newly fielded system and a mature supply support system for optimum benefit to the Department of Defense (DoD) and the taxpayer. Good logistics support planning in the early phases of the acquisition process will reduce the life cycle costs and increase operational availability. Applying these approaches to the Tactical Quiet Generator (TQG) would seem to provide significant benefit and offer other acquisition and logistics professionals valuable insights into the planning of future support arrangementshttp://www.archive.org/details/logisticssupport00daubU.S. Army (USA) autho

    Patterns of positive selection in seven ant genomes.

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    The evolution of ants is marked by remarkable adaptations that allowed the development of very complex social systems. To identify how ant-specific adaptations are associated with patterns of molecular evolution, we searched for signs of positive selection on amino-acid changes in proteins. We identified 24 functional categories of genes which were enriched for positively selected genes in the ant lineage. We also reanalyzed genome-wide data sets in bees and flies with the same methodology to check whether positive selection was specific to ants or also present in other insects. Notably, genes implicated in immunity were enriched for positively selected genes in the three lineages, ruling out the hypothesis that the evolution of hygienic behaviors in social insects caused a major relaxation of selective pressure on immune genes. Our scan also indicated that genes implicated in neurogenesis and olfaction started to undergo increased positive selection before the evolution of sociality in Hymenoptera. Finally, the comparison between these three lineages allowed us to pinpoint molecular evolution patterns that were specific to the ant lineage. In particular, there was ant-specific recurrent positive selection on genes with mitochondrial functions, suggesting that mitochondrial activity was improved during the evolution of this lineage. This might have been an important step toward the evolution of extreme lifespan that is a hallmark of ants
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