255 research outputs found

    The ARGUS Vertex Trigger

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    A fast second level trigger has been developed for the ARGUS experiment which recognizes tracks originating from the interaction region. The processor compares the hits in the ARGUS Micro Vertex Drift Chamber to 245760 masks stored in random access memories. The masks which are fully defined in three dimensions are able to reject tracks originating in the wall of the narrow beampipe of 10.5\,mm radius.Comment: gzipped Postscript, 27 page

    Construction and Performance of a Micro-Pattern Stereo Detector with Two Gas Electron Multipliers

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    The construction of a micro-pattern gas detector of dimensions 40x10 cm**2 is described. Two gas electron multiplier foils (GEM) provide the internal amplification stages. A two-layer readout structure was used, manufactured in the same technology as the GEM foils. The strips of each layer cross at an effective crossing angle of 6.7 degrees and have a 406 um pitch. The performance of the detector has been evaluated in a muon beam at CERN using a silicon telescope as reference system. The position resolutions of two orthogonal coordinates are measured to be 50 um and 1 mm, respectively. The muon detection efficiency for two-dimensional space points reaches 96%.Comment: 21 pages, 17 figure

    Determination of the Michel Parameters rho, xi, and delta in tau-Lepton Decays with tau --> rho nu Tags

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    Using the ARGUS detector at the e+ee^+ e^- storage ring DORIS II, we have measured the Michel parameters ρ\rho, ξ\xi, and ξδ\xi\delta for τ±l±ννˉ\tau^{\pm}\to l^{\pm} \nu\bar\nu decays in τ\tau-pair events produced at center of mass energies in the region of the Υ\Upsilon resonances. Using τρν\tau^\mp \to \rho^\mp \nu as spin analyzing tags, we find ρe=0.68±0.04±0.08\rho_{e}=0.68\pm 0.04 \pm 0.08, ξe=1.12±0.20±0.09\xi_{e}= 1.12 \pm 0.20 \pm 0.09, ξδe=0.57±0.14±0.07\xi\delta_{e}= 0.57 \pm 0.14 \pm 0.07, ρμ=0.69±0.06±0.08\rho_{\mu}= 0.69 \pm 0.06 \pm 0.08, ξμ=1.25±0.27±0.14\xi_{\mu}= 1.25 \pm 0.27 \pm 0.14 and ξδμ=0.72±0.18±0.10\xi\delta_{\mu}= 0.72 \pm 0.18 \pm 0.10. In addition, we report the combined ARGUS results on ρ\rho, ξ\xi, and ξδ\xi\delta using this work und previous measurements.Comment: 10 pages, well formatted postscript can be found at http://pktw06.phy.tu-dresden.de/iktp/pub/desy97-194.p

    Oxidative Stress and Vascular Function: Implications for Pharmacologic Treatments

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    Production of considerable amounts of reactive oxygen species (ROS) eventually leads to oxidative stress. A key role of oxidative stress is evident in the pathologic mechanisms of endothelial dysfunction and associated cardiovascular diseases. Vascular enzymes such as NADPH oxidases, xanthine oxidase, and uncoupled endothelial nitric oxide synthase are involved in the production of ROS. The question remains whether pharmacologic approaches can effectively combat the excessive ROS production in the vasculature. Interestingly, existing registered cardiovascular drugs can directly or indirectly act as antioxidants, thereby preventing the damaging effects of ROS. Moreover, new compounds targeting NADPH oxidases have been developed. Finally, food-derived compounds appear to be effective inhibitors of oxidative stress and preserve vascular function

    A Search for the Electric Dipole Moment of the Tau-Lepton

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    Using the ARGUS detector at the e+e- storage ring DORIS II, we have searched for the real and imaginary part of the electric dipole formfactor d_tau of the tau lepton in the production of tau pairs at q^2=100 GeV^2. This is the first direct measurement of this CP violating formfactor. We applied the method of optimised observables which takes into account all available information on the observed tau decay products. No evidence for CP violation was found, and we derive the following results: Re(d_tau)=(1.6+-.9)*10^(-16) ecm and Im(d_tau)=(-0.2+-0.8)*10^(-16) ecm, where statistical and systematic errors have been combined.Comment: 8 pages, 5 figures (10 subfigures

    Pleiotropic Benefit of Monomeric and Oligomeric Flavanols on Vascular Health - A Randomized Controlled Clinical Pilot Study

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    BACKGROUND: Cardiovascular diseases are expanding to a major social-economic burden in the Western World and undermine man's deep desire for healthy ageing. Epidemiological studies suggest that flavanol-rich foods (e.g. grapes, wine, chocolate) sustain cardiovascular health. For an evidenced-based application, however, sound clinical data on their efficacy are strongly demanded. METHODS: In a double-blind, randomized, placebo-controlled intervention study we supplemented 28 male smokers with 200 mg per day of monomeric and oligomeric flavanols (MOF) from grape seeds. At baseline, after 4 and 8 weeks we measured macro- and microvascular function and a cluster of systemic biomarkers for major pathological processes occurring in the vasculature: disturbances in lipid metabolism and cellular redox balance, and activation of inflammatory cells and platelets. RESULTS: In the MOF group serum total cholesterol and LDL decreased significantly (P ≤ 0.05) by 5% (n = 11) and 7% (n = 9), respectively in volunteers with elevated baseline levels. Additionally, after 8 weeks the ratio of glutathione to glutathione disulphide in erythrocytes rose from baseline by 22% (n = 15, P<0.05) in MOF supplemented subjects. We also observed that MOF supplementation exerts anti-inflammatory effects in blood towards ex vivo added bacterial endotoxin and significantly reduces expression of inflammatory genes in leukocytes. Conversely, alterations in macro- and microvascular function, platelet aggregation, plasma levels of nitric oxide surrogates, endothelin-1, C-reactive protein, fibrinogen, prostaglandin F2alpha, plasma antioxidant capacity and gene expression levels of antioxidant defense enzymes did not reach statistical significance after 8 weeks MOF supplementation. However, integrating all measured effects into a global, so-called vascular health index revealed a significant improvement of overall vascular health by MOF compared to placebo (P ≤ 0.05). CONCLUSION: Our integrative multi-biomarker approach unveiled the pleiotropic vascular health benefit of an 8 weeks supplementation with 200 mg/d MOF in humans. TRIAL REGISTRATION: ClinicalTrials.gov NCT00742287

    CMS physics technical design report : Addendum on high density QCD with heavy ions

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    Peer reviewe

    Integration of the End Cap TEC+ of the CMS Silicon Strip Tracker

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    The silicon strip tracker of the CMS experiment has been completed and inserted into the CMS detector in late 2007. The largest sub-system of the tracker is its end cap system, comprising two large end caps (TEC) each containing 3200 silicon strip modules. To ease construction, the end caps feature a modular design: groups of about 20 silicon modules are placed on sub-assemblies called petals and these self-contained elements are then mounted into the TEC support structures. Each end cap consists of 144 petals, and the insertion of these petals into the end cap structure is referred to as TEC integration. The two end caps were integrated independently in Aachen (TEC+) and at CERN (TEC--). This note deals with the integration of TEC+, describing procedures for end cap integration and for quality control during testing of integrated sections of the end cap and presenting results from the testing

    Reception Test of Petals for the End Cap TEC+ of the CMS Silicon Strip Tracker

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    The silicon strip tracker of the CMS experiment has been completed and was inserted into the CMS detector in late 2007. The largest sub system of the tracker are its end caps, comprising two large end caps (TEC) each containing 3200 silicon strip modules. To ease construction, the end caps feature a modular design: groups of about 20 silicon modules are placed on sub-assemblies called petals and these self-contained elements are then mounted onto the TEC support structures. Each end cap consists of 144 such petals, which were built and fully qualified by several institutes across Europe. Fro

    When male norms don't fit: Do traditional attitudes of female colleagues challenge men in non-traditional occupations?

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    Sobiraj S, Korek S, Weseler D, Mohr G. When male norms don't fit: Do traditional attitudes of female colleagues challenge men in non-traditional occupations? Sex Roles. 2011;65:798-812
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