15,671 research outputs found

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    Poisson transition rates from time-domain measurements with finite bandwidth

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    In time-domain measurements of a Poisson two-level system, the observed transition rates are always smaller than those of the actual system, a general consequence of finite measurement bandwidth in an experiment. This underestimation of the rates is significant even when the measurement and detection apparatus is ten times faster than the process under study. We derive here a quantitative form for this correction using a straightforward state-transition model that includes the detection apparatus, and provide a method for determining a system's actual transition rates from bandwidth-limited measurements. We support our results with computer simulations and experimental data from time-domain measurements of quasiparticle tunneling in a single-Cooper-pair transistor.Comment: 4 pages, 5 figure

    A TRANSLOG COST FUNCTION ANALYSIS OF U.S. AGRICULTURE: A DYNAMIC SPECIFICATION

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    This study has used an empirical approach developed by Urga and Walters (2003) to examine the implications of the short-run specification of the standard translog cost specification along with the possible implications of non-stationarity. We have estimated a dynamic translog cost specification complete with dynamic share equations for U.S. agriculture and compared it to the static, long-run specification. We found that the dynamic translog specification yielded more significant parameter estimates, and yielded results that are consistent with economic theory. In particular, the coefficient m (the adjustment cost parameter) determines the overall autoregressive structure of the model. The fact that its estimated value (0.36) is statistically different from zero at any conventional level of confidence indicates that the dynamic structure of the model is important. This finding illustrates the superiority of the short-run, dynamic specification over the static, long-run model.Agribusiness,

    A Translog Cost Function Analysis of U.S. Agriculture: 1948-1999

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    This study examines the implications of the short-run specification of the standard, static translog cost function along with the possible implications of non-stationarity by estimating a dynamic translog cost specification complete with dynamic share equations for the U.S. using an empirical approach developed by Urga and Walters (2003). We compare the results of the static, long-run model with those of a dynamic, short-run error-correction model in terms of 1) significance of the parameter estimates, and 2) consistency with economic theory.Research Methods/ Statistical Methods,

    Validation of the CMS Magnetic Field Map

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    The Compact Muon Solenoid (CMS) is a general purpose detector, designed to run at the highest luminosity at the CERN Large Hadron Collider (LHC). Its distinctive features include a 4 T superconducting solenoid with 6-m-diameter by 12.5-m-length free bore, enclosed inside a 10,000-ton return yoke made of construction steel. The return yoke consists of five dodecagonal three-layered barrel wheels and four end-cap disks at each end comprised of steel blocks up to 620 mm thick, which serve as the absorber plates of the muon detection system. To measure the field in and around the steel, a system of 22 flux loops and 82 3-D Hall sensors is installed on the return yoke blocks. A TOSCA 3-D model of the CMS magnet is developed to describe the magnetic field everywhere outside the tracking volume measured with the field-mapping machine. The magnetic field description is compared with the measurements and discussed.Comment: 7 pages, 5 figures, presented at 4th International Conference on Superconductivity and Magnetism 2014, April 27 - May 2, 2014, Antalya, Turkey. arXiv admin note: substantial text overlap with arXiv:1605.08778; text overlap with arXiv:1212.165

    A New Study of the Polarized Parton Densities in the Nucleon

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    We present a new next-to-leading order QCD analysis of the world data on inclusive polarized deep inelastic lepton-nucleon scattering adding to the old set of data the final SMC results, the HERMES proton and very recent SLAC/E155 deuteron data. We find an excellent fit to the data and present results for the polarized parton densities in different factorization schemes. These results are in a good agreement with what follows from the theory. We have also found that the main effect of the newly incorporated data is a better determination of the polarized gluon density.Comment: 9 pages, latex, 5 ps figures Presented at the 7th International Workshop on Deep Inelastic Scattering and QCD, Zeuthen, Germany, April 19-23, 199

    The incidence of pathogens in honey bee (Apis mellifera L) colonies in Finland and Great Britain

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    Dead adult bees collected from 26 apiaries distributed throughout Southern Finland were examined for protozoan, microsporidian and viral pathogens. Malpighamoeba mellificae was not found, but Nosema apis was detected at low levels in 11 of the 39 samples examined. Of the 51 samples examined for viruses, bee virus Y was detected in 2, cloudy wing virus in 14 and filamentous virus in 13. These findings are compared with pathogen incidence in honey bee colonies in Britain and discussed with reference to winter losses and Varroa jacobsoni infestation

    Iridovirus from bees

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    An iridovirus, Apis iridescent virus (AIV), isolated from sick adult specimens of Apis cerana (Hymenoptera) from Kashmir, closely resembles iridescent viruses from Tipula and Sericesthis spp. (TIV and SIV). However, AIV is only distantly related serologically to TIV and SIV and is even moderately related to several other similar viruses that were tested in tube precipitation tests with intact particles. AIV multiplied in Apis mellifera, forming cytoplasmic iridescent crystalline aggregates in several tissues, but unlike all the other iridoviruses tested, it failed to multiply in Galleria mellonella

    Twist-2 Light-Cone Pion Wave Function

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    We present an analysis of the existing constraints for the twist-2 light-cone pion wave function. We find that existing information on the pion wave function does not exclude the possibility that the pion wave function attains its asymptotic form. New bounds on the parameters of the pion wave function are presented.Comment: 7 pages, LaTeX, 1 PS-figure, one reference added, minor changes in the tex
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