10,682 research outputs found

    Prevalence of Rabbit Hemorrhagic Disease (RHD) in wild rabbits (Oryctolagus cuniculus) in Flanders, Belgium, 1999-2002

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    During the period of July 1999 through June 2002, carcasses of wild rabbits that had been shot or found dead and livers originating from wild rabbits that had been shot for consumption were collected in Flanders. One hundred and twelve carcasses were suitable for necropsy and histological and bacteriological analysis; histological analysis was possible in 41 livers. Considering the 112 rabbit carcasses only, Rabbit Hemorrhagic Disease (RHD) was found to be present in 33.9% of the cases. RHD was the most prevalent wild rabbit pathology detected in this study, before staphylococcosis (12.5%), and myxomatosis (10.7%). None of the liver samples from rabbits shot for consumption were positive for RHD. Of the 38 histologically RHD positive samples, 24 were analyzed with the hemagglutination (HA) technique, yielding 58.3% positive results. Seven samples that were histologically positive for RHD but HA negative were examined by transmission electron microscopy and were found positive for calicivirus. This proves that HA-negative RHD strains are circulating in the Flemish wild rabbit population

    Method and apparatus for shaping and enhancing acoustical levitation forces

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    A method and apparatus for enhancing and shaping acoustical levitation forces in a single-axis acoustic resonance system wherein specially shaped drivers and reflectors are utilized to enhance to levitation force and better contain fluid substance by means of field shaping is described

    Observations of Galactic Gamma-Ray Sources with H.E.S.S

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    H.E.S.S. results from the first three years of nominal operation are presented. Among the many exciting measurements that have been made, most gamma-ray sources are of Galactic origin. I will concentrate here on an overview of Galactic observations and summarise and discuss observations of selected objects of the different source types.Comment: 13 pages, 10 figures, based on a talk presented at the workshop 'Energy Budget in the High Energy Universe', Kashiwa, Japan 22 - 24 February 200

    Observations of the Crab Nebula with H.E.S.S. Phase II

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    The High Energy Stereoscopic System (H.E.S.S.) phase I instrument was an array of four 100m2100\,\mathrm{m}^2 mirror area Imaging Atmospheric Cherenkov Telescopes (IACTs) that has very successfully mapped the sky at photon energies above 100\sim 100\,GeV. Recently, a 600m2600\,\mathrm{m}^2 telescope was added to the centre of the existing array, which can be operated either in standalone mode or jointly with the four smaller telescopes. The large telescope lowers the energy threshold for gamma-ray observations to several tens of GeV, making the array sensitive at energies where the Fermi-LAT instrument runs out of statistics. At the same time, the new telescope makes the H.E.S.S. phase II instrument. This is the first hybrid IACT array, as it operates telescopes of different size (and hence different trigger rates) and different field of view. In this contribution we present results of H.E.S.S. phase II observations of the Crab Nebula, compare them to earlier observations, and evaluate the performance of the new instrument with Monte Carlo simulations.Comment: In Proceedings of the 34th International Cosmic Ray Conference (ICRC2015), The Hague, The Netherland

    Preliminary characterization of a one-axis acoustic system

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    The acoustic fields and levitation forces produced along the axis of a single-axis resonance system were measured. The system consisted of a St. Clair generator and a planar reflector. The levitation force was measured for bodies of various sizes and geometries (i.e., spheres, cylinders, and discs). The force was found to be roughly proportional to the volume of the body until the characteristic body radius reaches approximately 2/k (k = wave number). The acoustic pressures along the axis were modeled using Huygens principle and a method of imaging to approximate multiple reflections. The modeled pressures were found to be in reasonable agreement with those measured with a calibrated microphone

    Regularity of squarefree monomial ideals

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    We survey a number of recent studies of the Castelnuovo-Mumford regularity of squarefree monomial ideals. Our focus is on bounds and exact values for the regularity in terms of combinatorial data from associated simplicial complexes and/or hypergraphs.Comment: 23 pages; survey paper; minor changes in V.

    Water Quality and Sanitation, Aquatic Flora Fauna

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    Division of Power (DOP

    Kinetic Inductance of Josephson Junction Arrays: Dynamic and Equilibrium Calculations

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    We show analytically that the inverse kinetic inductance L1L^{-1} of an overdamped junction array at low frequencies is proportional to the admittance of an inhomogeneous equivalent impedance network. The ijthij^{th} bond in this equivalent network has an inverse inductance Jijcos(θi0θj0Aij)J_{ij}\cos(\theta_i^0-\theta_j^0-A_{ij}), where JijJ_{ij} is the Josephson coupling energy of the ijthij^{th} bond, θi0\theta_i^0 is the ground-state phase of the grain ii, and AijA_{ij} is the usual magnetic phase factor. We use this theorem to calculate L1L^{-1} for square arrays as large as 180×180180\times 180. The calculated L1L^{-1} is in very good agreement with the low-temperature limit of the helicity modulus γ\gamma calculated by conventional equilibrium Monte Carlo techniques. However, the finite temperature structure of γ\gamma, as a function of magnetic field, is \underline{sharper} than the zero-temperature L1L^{-1}, which shows surprisingly weak structure. In triangular arrays, the equilibrium calculation of γ\gamma yields a series of peaks at frustrations f=12(11/N)f = \frac{1}{2}(1-1/N), where NN is an integer 2\geq 2, consistent with experiment.Comment: 14 pages + 6 postscript figures, 3.0 REVTe

    Electrowetting of liquid marbles

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    Electrowetting of water drops on structured superhydrophobic surfaces are known to cause an irreversible change from a slippy (Cassie-Baxter) to a sticky (Wenzel) regime. An alternative approach to using a water drop on a superhydrophobic surface to obtain a non-wetting system is to use a liquid marble on a smooth solid substrate. A liquid marble is a droplet coated in hydrophobic grains, which therefore carries its own solid surface structure as a conformal coating. Such droplets can be considered as perfect non-wetting systems having contact angles to smooth solid substrates of close to 180 degrees. In this work we report the electrowetting of liquid marbles made of water coated with hydrophobic lycopodium grains and show that the electrowetting is completely reversible. Marbles are shown to return to their initial contact angle for both ac and dc electrowetting and without requiring a threshold voltage to be exceeded. Furthermore, we provide a proof-of-principle demonstration that controlled motion of marbles on a finger electrode structure is possible
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