9,948 research outputs found

    Charged Pion Energy Reconstruction in the ATLAS Barrel Calorimeter

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    The intrinsic performance of the ATLAS barrel and extended barrel calorimeters for the measurement of charged pions is presented. Pion energy scans (E = 20, 50, 200, 400 and 1000 GeV) at two pseudo-rapidity points (η\eta = 0.3 and 1.3) and pseudorapidity scans (0.2<η<1.8-0.2 < \eta < 1.8) with pions of constant transverse energy (ET=20E_T = 20 and 50 GeV) are analysed. A simple approach, that accounts in first order for non-compensation and dead material effects, is used for the pion energy reconstruction. The intrinsic performances of the calorimeter are studied: resolution, linearity, effect of dead material, tails in the energy distribution. The effect of electronic noise, cell energy cuts and restricted cone size are investigated.Comment: Latex, 17 pages, 10 figure

    Optimal Distributed Power Generation Under Network-Load Constraints

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    In electrical power networks nowadays more and more customers are becoming power-producers, mainly because of the development of novel components for decentralized power generation (solar panels, small wind turbines and heat pumps). This gives rise to the question how many units of each type (solar panel, small wind turbine or central heating power units) can be inserted into any transmission line in the network, such that under given distributions on the typical production and consumption over time, the maximum loads on the lines and components will not be exceeded. In this paper, we present a linear programming model for maximizing the amount of decentralized power generation while respecting the load limitations of the network. We describe a prototype showing that for an example network the maximization problem can be solved efficiently. We also modeled the case were the power consumption and decentralized power generation are considered as stochastic variables, which is inherently more complex

    Jet and missing transverse energy at the LHC

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    Many physics channels of interest at the LHC involve the measurement of jets and missing transverse momentum. The various physics effects playing a role in the chain that goes from an initial parton produced in the hard scattering process to a reconstructed and calibrated jet in the calorimeter are reviewed. The most relevant issues for a good performance in missing transverse momentum measurement are described. The expected performances of the ATLAS and CMS detectors are presented for some of the characteristics physics channels at the LHC. Jet and missing transverse energy triggers are discussed

    The first ultra-high resolution Digital Terrain Model of the shallow-water sector around Lipari Island (Aeolian Islands, Italy)

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    Very high resolution bathymetric map obtained through multibeam echosounders data are crucial to generate accurate Digital Terrain Models from which the morphological setting of active volcanic areas can be analyzed in detail. Here we show and discuss the main results from the first multibeam bathymetric survey performed in shallow-waters around the island of Lipari, the largest and the most densely populated of the Aeolian Islands (southern Italy). Data have been collected in the depth range of 0.1-150 m and complete the already existent high-resolution multibeam bathymetry realized between 100 and 1300 m water depth. The new ultrahigh resolution bathymetric maps at 0.1-0.5 m provide new insights on the shallow seafloor of Lipari, allowing to detail a large spectrum of volcanic, erosive-depositional and anthropic features. Moreover, the presented data allow outlining the recent morphological evolution of the shallow coastal sector of this active volcanic island, indicating the presence of potential geo-hazard factors in shallow waters

    Business Success and Businesses' Beauty Capital

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    We examine whether a difference in pay for beauty is supported by different productivity of people according to looks. Using a sample of advertising firms, we find that those firms with better-looking executives have higher revenues and faster growth than do otherwise identical firms whose executives are not so good-looking. The impact on revenue far exceeds the likely effect of beauty on the executives' wages. This suggests that their beauty creates firm-specific investments, in the form of improved relationships within work groups, the returns to which are shared by the firm and the executive.

    Efficiency of radial transport of ices in protoplanetary disks probed with infrared observations: the case of CO2_2

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    The efficiency of radial transport of icy solid material from outer disk to the inner disk is currently unconstrained. Efficient radial transport of icy dust grains could significantly alter the composition of the gas in the inner disk. Our aim is to model the gaseous CO2_2 abundance in the inner disk and use this to probe the efficiency of icy dust transport in a viscous disk. Features in the simulated CO2_2 spectra are investigated for their dust flux tracing potential. We have developed a 1D viscous disk model that includes gas and grain motions as well as dust growth, sublimation and freeze-out and a parametrisation of the CO2_2 chemistry. The thermo-chemical code DALI was used to model the mid-infrared spectrum of CO2_2, as can be observed with JWST-MIRI. CO2_2 ice sublimating at the iceline increases the gaseous CO2_2 abundance to levels equal to the CO2_2 ice abundance of 105\sim 10^{-5}, which is three orders of magnitude more than the gaseous CO2_2 abundances of 108\sim 10^{-8} observed by Spitzer. Grain growth and radial drift further increase the gaseous CO2_2 abundance. A CO2_2 destruction rate of at least 101110^{-11} s1^{-1} is needed to reconcile model prediction with observations. This rate is at least two orders of magnitude higher than the fastest known chemical destruction rate. A range of potential physical mechanisms to explain the low observed CO2_2 abundances are discussed. Transport processes in disks can have profound effects on the abundances of species in the inner disk. The discrepancy between our model and observations either suggests frequent shocks in the inner 10 AU that destroy CO2_2, or that the abundant midplane CO2_2 is hidden from our view by an optically thick column of low abundance CO2_2 in to the disk surface XDR/PDR. Other molecules, such as CH4_4 or NH3_3, can give further handles on the rate of mass transport.Comment: Accepted for publication in A&A, 18 pages, 13 figures, abstract abridge

    Natural polymorphism in the thrombospondin-related adhesive protein of Plasmodium falciparum

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    We have developed a typing system using natural sequence variation in the thrombospondin-related adhesive protein (TRAP) gene of Plasmodium falciparum. This method permits a haplotype to be assigned to any particular TRAP gene. We have applied this method to a hospital-based, case control-study in Mali. Previous sequence variation and conservation in TRAP has been confirmed. Particular TRAP haplotypes can be used as geographic hallmarks. Because of the high level of conflict between characters, we have examined the phylogenetic relationships between parasites using a network approach. Having received patient samples from urban and periurban areas of Bamako, the majority of haplotypes were closely related and distinct from TRAP sequences present in other continents. This suggests that the structure of TRAP can only tolerate a limited number of sequence variations to preserve its function but that this is sufficient to allow the parasite to evade the host's immune system until a long-lived immune response can be maintained. It may also reflect host genetics in that certain variants may escape the host immune response more efficiently than others. For vaccine design, sequences from the major regional variants may need to be considered in the production of effective subunit vaccines

    Effect of Feathers as Nest Insulation on Incubation Behavior and Reproductive Performance of Tree Swallows (\u3cem\u3eTachycineta bicolor\u3c/em\u3e)

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    Many species of birds line their nests with feathers, presumably because of the insulative qualities of feathers and because feathers may act as a barrier between nest parasites and nestlings. In 1993, we experimentally examined the role of feathers as nest insulation on the incubation behavior, nestling growth, and reproductive performance of Tree Swallows (Tachycineta bicolor) nesting in boxes in western Michigan. There were no significant differences between the incubation rhythms of females with experimental nests (i.e. no feathers) and females with control nests (i.e. with feathers). Nestlings that were reared in control nests had significantly longer right tarsi and right wing chords; their masses were significantly greater than nestlings reared in experimental nests. In addition, nested analyses of variance indicated that both female age class (i.e. second year, after second year, or after hatching year) and the brood within which a nestling was reared had significant effects on nestling growth until nestling day 12. Whether an individual nestling was infected with ectoparasites was independent of whether it was reared in an experimental or control nest. Nest insulation affected reproductive performance: females with experimental nests had significantly longer incubation periods and produced significantly fewer fledglings than did females with control nests. These results suggest that nest insulation may be an important factor influencing incubation behavior, nestling growth, and reproductive performance of Tree Swallows in western Michigan
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