13,179 research outputs found

    Performance of the OPAL Si-W luminometer at LEP I-II

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    A pair of compact Silicon-Tungsten calorimeters was operated in the OPAL experiment at LEP to measure the integrated luminosity from detection of Bhabha electrons scattered at angles between 25 and 58 mrad from the beam line. In the eight years from 1993 to 2000 the detector worked first at the Z mass peak and then at center of mass energies up to 209 GeV. The fine radial and longitudinal segmentation (2.5mm x 1X0) allowed the radial position of electron and photon showers to be measured with a resolution of 130-170 microns and a residual radial bias as small as 7 microns. Reducing the bias in the definition of the inner acceptance radius was the key element in obtaining an experimental systematic error on the integrated luminosity of only 3.4 10^-4. The performance of the detector at both LEP-I and LEP-II is reviewed. Energy resolution, sensitivity to overlapping electromagnetic showers and sensitivity to minimum ionizing particles are discussed.Comment: 9 pages, 7 figures, 10th International Conference on Calorimetry in High Energy Physics. http://3w.hep.caltech.edu/calor02

    Arkansas Animal Science Department Report 2002

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    The faculty and staff of the Animal Science Program are pleased to present the sixth edition of the Arkansas Animal Science Report. As with virtually all programs in the country, budget constraints presented serious challenges to teaching, research, and extension programming. However, the faculty and staff responded with innovation, good management, and hard work to maintain a productive program designed to benefit the students of the University and the citizens of the state. We are committed to remaining faithful to our Land-Grant mission. A sincere thank you is owed to Dr. Zelpha Johnson and Dr. Wayne Kellogg for editing this publication. We are proud that Meat and Poultry magazine ranked the animal and poultry programs at the University of Arkansas among the top four in the United States for 2003. This is a tribute to the dedicated and talented faculty in the Departments of Animal Science, Poultry Science, and Food Science and to their high level of cooperation

    Milking management and housing studies

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    Digitized 2007 AES.Includes bibliographical references (page 10)

    A compact high-flux cold atom beam source

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    We report on an efficient and compact high-flux Cs atom beam source based on a retro-reflected two-dimensional magneto-optical trap (2D MOT). We realize an effective pushing field component by tilting the 2D MOT collimators towards a separate three-dimensional magneto-optical trap (3D MOT) in ultra-high vacuum. This technique significantly improved 3D MOT loading rates to greater than 8×1098 \times 10^9 atoms/s using only 20 mW of total laser power for the source. When operating below saturation, we achieve a maximum efficiency of 6.2×10116.2 \times 10^{11} atoms/s/W

    Solar Wind Electric Fields in the Ion Cyclotron Frequency Range

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    Measurements of fluctuations of electric fields in the frequency range from a fraction of one Hz to 12.5 Hz are presented, and corrected for the Lorentz transformation of magnetic fluctuations to give the electric fields in the plasma frame. The electric fields are large enough to provide the dominant force on the ions of the solar wind in the region near the ion cyclotron frequency of protons, larger than the force due to magnetic fluctuations. They provide sufficient velocity space diffusion or heating to counteract conservation of magnetic moment in the expanding solar wind to maintain nearly isotropic velocity distributions

    Motion sickness susceptibility under weightless and hypergravity conditions generated by parabolic flight

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    Motion sickness susceptibility under weightless and hypergravity conditions generated by parabolic fligh

    Extragalactic H 2 regions in the UV: Implications for primeval galaxies and quasars

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    Three extragalactic regions of rapid star formation with red shifts great enough to separate the L alpha region from geocoronal L alpha were observed with the IUE satellite. Only the low metal abundance object had detectable L alpha emission. L alpha is therefore expected to be weak or absent in collapsed primeval galaxies. The detected object has a L alpha H beta identical to that of quasars
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