136 research outputs found

    The Organisation and Politics of Social Forums

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    Social Forums have become key spaces for the articulation of discontent and radical politics today. The first World Social Forum (WSF) took place in Porto Alegre, Brazil, in January 2001, and since then numerous other Social Forums have been organised in many different locations at local, regional and global levels

    Reliable and redundant FPGA based read-out design in the ATLAS TileCal Demonstrator

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    The Tile Calorimeter at ATLAS is a hadron calorimeter based on steel plates and scintillating tiles read out by PMTs. The current read-out system uses standard ADCs and custom ASICs to digitize and temporarily store the data on the detector. However, only a subset of the data is actually read out to the counting room. The on-detector electronics will be replaced around 2023. To achieve the required reliability the upgraded system will be highly redundant. Here the ASICs will be replaced with Kintex-7 FPGAs from Xilinx. This, in addition to the use of multiple 10 Gbps optical read-out links, will allow a full read-out of all detector data. Due to the higher radiation levels expected when the beam luminosity is increased, opportunities for repairs will be less frequent. The circuitry and firmware must therefore be designed for sufficiently high reliability using redundancy and radiation tolerant components. Within a year, a hybrid demonstrator including the new read-out system will be installed in one slice of the ATLAS Tile Calorimeter. This will allow the proposed upgrade to be thoroughly evaluated well before the planned 2023 deployment in all slices, especially with regard to long term reliability. Different firmware strategies alongside with their integration in the demonstrator are presented in the context of high reliability protection against hardware malfunction and radiation induced errors

    Highly efficient passive Tesla valves for microfluidic applications

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    A multistage optimization method is developed yielding Tesla valves that are efficient even at low flow rates, characteristic, e.g., for almost all microfluidic systems, where passive valves have intrinsic advantages over active ones. We report on optimized structures that show a diodicity of up to 1.8 already at flow rates of 20 Όl s−1 corresponding to a Reynolds number of 36. Centerpiece of the design is a topological optimization based on the finite element method. It is set-up to yield easy-to-fabricate valve structures with a small footprint that can be directly used in microfluidic systems. Our numerical two-dimensional optimization takes into account the finite height of the channel approximately by means of a so-called shallow-channel approximation. Based on the three-dimensionally extruded optimized designs, various test structures were fabricated using standard, widely available microsystem manufacturing techniques. The manufacturing process is described in detail since it can be used for the production of similar cost-effective microfluidic systems. For the experimentally fabricated chips, the efficiency of the different valve designs, i.e., the diodicity defined as the ratio of the measured pressure drops in backward and forward flow directions, respectively, is measured and compared to theoretical predictions obtained from full 3D calculations of the Tesla valves. Good agreement is found. In addition to the direct measurement of the diodicities, the flow profiles in the fabricated test structures are determined using a two-dimensional microscopic particle image velocimetry (ÎŒPIV) method. Again, a reasonable good agreement of the measured flow profiles with simulated predictions is observed

    Evaluation vertragsĂ€rztlicher und vertragszahnĂ€rztlicher Kooperationen mit Pflegeeinrichtungen gemĂ€ĂŸ § 119b SGB V: Untersuchung im Auftrag des SĂ€chsischen Staatsministeriums fĂŒr Soziales und Verbraucherschutz

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    Mit dem Ziel, die Ă€rztliche und zahnĂ€rztliche Versorgung von Pflegeheimbewohnern zu verbessern und auszubauen, wurde im Jahr 2008 mit dem Gesetz zur strukturellen Weiterentwicklung der Pflegeversicherung (Pflege-Weiterentwicklungsgesetz) § 119b neu in das SGB V eingefĂŒgt. Vor diesem Hintergrund beauftragte das SĂ€chsische Staatsministerium fĂŒr Soziales und Verbraucherschutz (SMS) im Februar 2018 AGENON – Gesellschaft fĂŒr Forschung und Entwicklung im Gesundheitswesen mbH mit der „Evaluation vertragsĂ€rztlicher und vertragszahnĂ€rztlicher Kooperationen mit Pflegeeinrichtungen gemĂ€ĂŸ § 119b SGB V“. Der Bericht prĂ€sentiert die Studienergebnisse und gibt Handlungsempfehlungen. Redaktionsschluss: 28.02.201

    IceCube - the next generation neutrino telescope at the South Pole

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    IceCube is a large neutrino telescope of the next generation to be constructed in the Antarctic Ice Sheet near the South Pole. We present the conceptual design and the sensitivity of the IceCube detector to predicted fluxes of neutrinos, both atmospheric and extra-terrestrial. A complete simulation of the detector design has been used to study the detector's capability to search for neutrinos from sources such as active galaxies, and gamma-ray bursts.Comment: 8 pages, to be published with the proceedings of the XXth International Conference on Neutrino Physics and Astrophysics, Munich 200

    Sensitivity of the IceCube Detector to Astrophysical Sources of High Energy Muon Neutrinos

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    We present the results of a Monte-Carlo study of the sensitivity of the planned IceCube detector to predicted fluxes of muon neutrinos at TeV to PeV energies. A complete simulation of the detector and data analysis is used to study the detector's capability to search for muon neutrinos from sources such as active galaxies and gamma-ray bursts. We study the effective area and the angular resolution of the detector as a function of muon energy and angle of incidence. We present detailed calculations of the sensitivity of the detector to both diffuse and pointlike neutrino emissions, including an assessment of the sensitivity to neutrinos detected in coincidence with gamma-ray burst observations. After three years of datataking, IceCube will have been able to detect a point source flux of E^2*dN/dE = 7*10^-9 cm^-2s^-1GeV at a 5-sigma significance, or, in the absence of a signal, place a 90% c.l. limit at a level E^2*dN/dE = 2*10^-9 cm^-2s^-1GeV. A diffuse E-2 flux would be detectable at a minimum strength of E^2*dN/dE = 1*10^-8 cm^-2s^-1sr^-1GeV. A gamma-ray burst model following the formulation of Waxman and Bahcall would result in a 5-sigma effect after the observation of 200 bursts in coincidence with satellite observations of the gamma-rays.Comment: 33 pages, 13 figures, 6 table

    On the selection of AGN neutrino source candidates for a source stacking analysis with neutrino telescopes

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    The sensitivity of a search for sources of TeV neutrinos can be improved by grouping potential sources together into generic classes in a procedure that is known as source stacking. In this paper, we define catalogs of Active Galactic Nuclei (AGN) and use them to perform a source stacking analysis. The grouping of AGN into classes is done in two steps: first, AGN classes are defined, then, sources to be stacked are selected assuming that a potential neutrino flux is linearly correlated with the photon luminosity in a certain energy band (radio, IR, optical, keV, GeV, TeV). Lacking any secure detailed knowledge on neutrino production in AGN, this correlation is motivated by hadronic AGN models, as briefly reviewed in this paper. The source stacking search for neutrinos from generic AGN classes is illustrated using the data collected by the AMANDA-II high energy neutrino detector during the year 2000. No significant excess for any of the suggested groups was found.Comment: 43 pages, 12 figures, accepted by Astroparticle Physic

    Search for neutralino dark matter with the AMANDA neutrino detector

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    Air showers with IceCube : First Engineering Data

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