7,824 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

    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

    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.

    Epistemologies of Land Relations in India’s Tribal Frontier

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    This article contributes to the burgeoning critical literature on Naga lifeworlds by using a heterodox Foucaultian and Marxist framework. The analysis is structured as a genealogy that reinterprets the ways that historical epistemologies have shaped contemporary land relations in Nagaland. Our genealogy draws on place-based interviews to foreground what the history of land relations mean to Nagas today. The discussion sheds new light on (i) the epistemological bearings of gennas on the present-day social realities of Naga-Christianity; (ii) territoriality as an epistemology that reified the village-centered ownership of land; (iii) epistemic ruptures of subjectivation under British colonialism. The paper ends by contextualizing the genealogy of Naga land relations to redress its biased representations and culture of alterity by mainstream media and political outlets in India

    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

    Effect of electrical stimulation of carcasses from Dorper sheep with two permanent incisors on the consumer acceptance of mutton: review article

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    The inconsistency in the eating quality characteristics of meats, predominantly tenderness, is probably the most critical problem faced by the meat industry worldwide. Consumers consider tenderness to be the single most important component of meat quality. An alternative method for increasing meat tenderness may exist in the form of electrical stimulation of the carcass shortly following slaughter. The aim of this research was to study the effect of electrical stimulation on the consumer acceptance of, preference for and consumption intent regarding mutton of the recently introduced class-AB sheep carcasses (carcasses from sheep with one to two permanent incisors) in South Africa. A total of 22 wethers of class-AB, weighing between 45 and 50 kg, was selected from a homogeneous group of Dorpers. Carcasses were divided into two groups, one was electrically stimulated (0.4 amp/h for 45 sec) and the other group not stimulated. Samples of the left M. longissimus thoracis et lumborum of both groups were oven roasted and a consumer panel evaluated the acceptability of the mutton regarding certain sensory characteristics. Three consumer sensory tests, namely the hedonic rating of the acceptability of each sensory attribute, a preference test and a food action rating test, were conducted in sequence. The acceptability of the juiciness, tenderness, flavour and overall acceptability were not significantly influenced by the electrical stimulation of carcasses. Samples from both the electrically stimulated and non-stimulated carcasses were highly acceptable to consumers. No significant differences in preference or percentage cooking losses were obtained. The present results indicate that electrical stimulation of class-AB carcasses did not have a significant influence on the consumer's acceptance of, nor consumption intent towards the class-AB mutton. This study shows that consumers revealed a positive attitude by declaring their intention to eat samples from both electrically stimulated and non-electrically stimulated carcasses once a week. Moreover, the variation in shear force values of meat samples from the electrically stimulated group was less compared to that of the non-stimulated group, indicating that electrical stimulation can successfully be applied to reduce the variation in tenderness within the class-AB mutton. Keywords: Class AB-mutton, Electrical stimulation, Consumer acceptance, Tenderness South African Journal of Animal Science Vol.33(3) 2003: 206-21
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