2,148 research outputs found

    The movement of spray drift near a live shelterbelt

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    Non-Peer ReviewedThere has been recent interest in the use of shelterbelts to mitigate spray drift and protect downwind areas. Previous research has investigated the interaction of spray drift and shelterbelts using model shelterbelts, wind tunnel experiments, and numerical modeling; however, there is limited knowledge on the movement of spray drift near a live shelterbelt in field conditions. These experiments measured the ground deposition and airborne concentration of drift near a live carragana/chokecherry mix shelterbelt. It was found that when compared to open field experiments where there was no shelterbelt, the mass of ground deposit was less in the lee of the shelterbelt for a distance of 0-10H downwind of the shelterbelt (where H is the height of the shelterbelt). Further than 10H downwind of the shelterbelt, the mass of ground deposit was similar to the open field. There was an 88% reduction in airborne drift exiting the shelterbelt as compared to the drift entering the shelterbelt, which likely caused the reduction in deposition in the shelterbelt’s lee. It was shown that there was a larger proportion of drift diverted over the top of the shelterbelt as compared to the drift exiting the shelterbelt. Although not apparent in these experiments, this suggested that there may be increased deposition further downwind from the shelterbelt as compared to the open field

    Study of polarization observables in double pion photoproduction on the proton

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    Using a model for two pion photoproduction on the proton previously tested in total cross sections and invariant mass distributions, we evaluate here polarization observables on which recent experiments are providing new information. We evaluate cross sections for spin 1/2 and 3/2, which are measured at Mainz and play an important role in tests of the GHD sum rule. We also evaluate the proton polarization asymmetry ÎŁ\Sigma which is currently under investigation at GRAAL in Grenoble.Comment: 23 pages, 14 ps figure

    Women, ethnicity and nationalisms in Latin America

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    Gutierrez Chong, Natividad (ed. lit.) "Women, ethnicity and nationalisms in Latin America". Aldershot : Ashgate, 2007. 235 p. ISBN 978-075-464-925-0Nationalism is a multifaceted phenomenon that has recently become a focus of redefinition through new multidisciplinary and multi-method approaches. The complex links among gender, ethnicity and nationalism, neglected for a long time in academic research, are increasingly receiving coverage in the scholarly literature. The book "Women, Ethnicity and Nationalisms in Latin America”, edited by Natividad Gutiérrez Chong, systematically explores these links in the context of Latin America, with case studies covering Argentina, Ecuador, Bolivia and Mexico. Contributions are by leading Latin American scholars from diverse academic fields who share the aim of overcoming the limitations of the Eurocentric and androcentric framework that characterizes the main approaches to nationalism

    π\piNN coupling and two-pion photoproduction on the nucleon

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    Effects of non-resonant photoproductions arising from two different πNN\pi NN couplings are investigated in the γN→ππN\gamma N\to\pi\pi N reaction. We find that the pseudoscalar (PS) πNN\pi NN coupling is generally preferable to the pseudovector (PV) πNN\pi NN coupling and particularly the total cross sections are successfully described by the model with the PS πNN\pi NN coupling. In order to see the difference between the two couplings, we also show the results of invariant mass spectra and helicity-dependent cross sections in various isospin channels calculated with the PS and PV couplings.Comment: 35 pages, 11 figures, minor changes and version to be published in Phys.Rev.

    Alginate reduces the increased uptake of cholesterol and glucose in overweight male subjects: a pilot study

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    Dietary fibers are of particular interest in the prevention and management of obesity and consequent pathologies. Among the proposed mechanisms of action of fiber is the modulation of nutrient uptake from the small intestine. We have used a crossover study design in human subjects to monitor the uptake of glucose, cholesterol, and triacylglycerols in human subjects with normal and high body mass index. Our data demonstrate that uptakes of glucose, triacylglycerols, and cholesterol are all increased with increasing body fat. We demonstrate that treatment with a 1.5-g dose of a strong-gelling alginate may restore uptake of cholesterol and glucose to the levels of healthy subjects. These data indicate a potential therapeutic application of gelling fibers. (C) 2008 Published by Elsevier Inc

    Moduli-Space Dynamics of Noncommutative Abelian Sigma-Model Solitons

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    In the noncommutative (Moyal) plane, we relate exact U(1) sigma-model solitons to generic scalar-field solitons for an infinitely stiff potential. The static k-lump moduli space C^k/S_k features a natural K"ahler metric induced from an embedding Grassmannian. The moduli-space dynamics is blind against adding a WZW-like term to the sigma-model action and thus also applies to the integrable U(1) Ward model. For the latter's two-soliton motion we compare the exact field configurations with their supposed moduli-space approximations. Surprisingly, the two do not match, which questions the adiabatic method for noncommutative solitons.Comment: 1+15 pages, 2 figures; v2: reference added, to appear in JHE

    Width of Sunspot Generating Zone and Reconstruction of Butterfly Diagram

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    Based on the extended Greenwich-NOAA/USAF catalogue of sunspot groups it is demonstrated that the parameters describing the latitudinal width of the sunspot generating zone (SGZ) are closely related to the current level of solar activity, and the growth of the activity leads to the expansion of SGZ. The ratio of the sunspot number to the width of SGZ shows saturation at a certain level of the sunspot number, and above this level the increase of the activity takes place mostly due to the expansion of SGZ. It is shown that the mean latitudes of sunspots can be reconstructed from the amplitudes of solar activity. Using the obtained relations and the group sunspot numbers by Hoyt and Schatten (1998), the latitude distribution of sunspot groups ("the Maunder butterfly diagram") for the 18th and the first half of the 19th centuries is reconstructed and compared with historical sunspot observations.Comment: 16 pages, 11 figures; accepted by Solar Physics; the final publication will be available at www.springerlink.co

    Daily ingestion of alginate reduces energy intake in free-living subjects

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    Sodium alginate is a seaweed-derived fibre that has previously been shown to moderate appetite in models of acute feeding. The mechanisms underlying this effect may include slowed gastric clearance and attenuated uptake from the small intestine. In order to assess whether alginate could be effective as a means of appetite control in free-living adults, 68 males and females (BMI range: 18.50-32.81 kgl M-2) completed this randomised, controlled two-way crossover intervention to compare the effects of 7 day daily ingestion of a strong-gelling sodium alginate formulation against a control. A sodium alginate with a high-guluronate content was chosen because, upon ingestion, it forms a strong gel in the presence of calcium ions. Daily preprandial ingestion of the sodium alginate formulation produced a significant 134.8 kcal (7%) reduction in mean daily energy intake. This reduced energy intake was underwritten by significant reductions in mean daily carbohydrate, sugar, fat, saturated fat and protein intakes. The absence of any significant interaction effects between the main effect of preload type and those of gender, BMI classification and/or timing of preload delivery indicates the efficacy of this treatment for individuals in different settings. These findings suggest a possible role for a strong-gelling sodium alginate formulation in the future management of overweight and obesity. (C) 2008 Elsevier Ltd. All rights reserved

    On the background in the γp→ω(π0γ)p\gamma p \to \omega(\pi^0\gamma) p reaction and mixed event simulation

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    In this paper we evaluate sources of background for the γp→ωp\gamma p \to \omega p, with the ω\omega detected through its π0γ\pi^0 \gamma decay channel, to compare with the experiment carried out at ELSA. We find background from γp→π0π0p\gamma p \to \pi^0 \pi^0 p followed by decay of a π0\pi^0 into two γ\gamma, recombining one π0\pi^0 and one γ\gamma, and from the γp→π0ηp\gamma p \to \pi^0 \eta p reaction with subsequent decay of the η\eta into two photons. This background accounts for the data at π0γ\pi^0 \gamma invariant masses beyond 700 MeV, but strength is missing at lower invariant masses which was attributed to photon misidentification events, which we simulate to get a good reproduction of the experimental background. Once this is done, we perform an event mixing simulation to reproduce the calculated background and we find that the method provides a good description of the background at low π0γ\pi^0 \gamma invariant masses but fakes the background at high invariant masses, making background events at low invariant masses, which are due to γ\gamma misidentification events, responsible for the background at high invariant masses which is due to the γp→π0π0p\gamma p \to \pi^0 \pi^0 p and γp→π0ηp\gamma p \to \pi^0 \eta p reactions.Comment: 10 pages, 5 figure
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