4,457 research outputs found
Screening in (2+1)D pure gauge theory at high temperatures
We compute heavy quark potentials in pure gauge at high temperatures
in dimensions and confront them with expectations emerging from
perturbative calculations.Comment: 3 pages, latex, 4 figures, uu, Contribution to LATTICE 9
The string tension in SU(N) gauge theory from a careful analysis of smearing parameters
We report a method to select optimal smearing parameters before production
runs and discuss the advantages of this selection for the determination of the
string tension.Comment: Contribution to Lat97 poster session, title was 'How to measure the
string tension', 3 pages, 5 colour eps figure
A probabilistic assessment of climate change impacts on yield and nitrogen leaching from winter wheat in Denmark
Climate change will impact agricultural production both directly and indirectly, but uncertainties related to likely impacts constrain current political decision making on adaptation. This analysis focuses on a methodology for applying probabilistic climate change projections to assess modelled wheat yields and nitrate leaching from arable land in Denmark. The probabilistic projections describe a range of possible changes in temperature and precipitation. Two methodologies to apply climate projections in impact models were tested. Method A was a straightforward correction of temperature and precipitation, where the same correction was applied to the baseline weather data for all days in the year, and method B used seasonal changes in precipitation and temperature to correct the baseline weather data. Based on climate change projections for the time span 2000 to 2100 and two soil types, the mean impact and the uncertainty of the climate change projections were analysed. Combining probability density functions of climate change projections with crop model simulations, the uncertainty and trends in nitrogen (N) leaching and grain yields with climate change were quantified. The uncertainty of climate change projections was the dominating source of uncertainty in the projections of yield and N leaching, whereas the methodology to seasonally apply climate change projections had a minor effect. For most conditions, the probability of large yield reductions and large N leaching losses tracked trends in mean yields and mean N leaching. The impacts of the uncertainty in climate change were higher for loamy sandy soil than for sandy soils due to generally higher yield levels for loamy sandy soils. There were large differences between soil types in response to climate change, illustrating the importance of including soil information for regional studies of climate change impacts on cropping systems
Calcitonin gene-related peptide receptor antagonist BIBN 4096 BS for the acute treatment of migraine
Background: Calcitonin gene–related peptide (CGRP) may have a causative role in migraine. We therefore hypothesized that a CGRP-receptor antagonist might be effective in the treatment of migraine attacks.
Methods: In an international, multicenter, double-blind, randomized clinical trial of BIBN 4096 BS, a highly specific and potent nonpeptide CGRP-receptor antagonist, 126 patients with migraine received one of the following: placebo or 0.25, 0.5, 1, 2.5, 5, or 10 mg of BIBN 4096 BS intravenously over a period of 10 minutes. A group-sequential adaptive treatment-assignment design was used to minimize the number of patients exposed.
Results: The 2.5-mg dose was selected, with a response rate of 66 percent, as compared with 27 percent for placebo (P=0.001). The BIBN 4096 BS group as a whole had a response rate of 60 percent. Significant superiority over placebo was also observed with respect to most secondary end points: the pain-free rate at 2 hours; the rate of sustained response over a period of 24 hours; the rate of recurrence of headache; improvement in nausea, photophobia, phonophobia, and functional capacity; and the time to meaningful relief. An effect was apparent after 30 minutes and increased over the next few hours. The overall rate of adverse events was 25 percent after the 2.5-mg dose of the drug and 20 percent for the BIBN 4096 BS group as a whole, as compared with 12 percent for placebo. The most frequent side effect was paresthesia. There were no serious adverse events.
Conclusions: The CGRP antagonist BIBN 4096 BS was effective in treating acute attacks of migraine
Extra-Dimensions effects on the fermion-induced quantum energy in the presence of a constant magnetic field
We consider a U(1) gauge field theory with fermion fields (or with scalar
fields) that live in a space with extra compact dimensions, and we
compute the fermion-induced quantum energy in the presence of a constant
magnetic field, which is directed towards the x_3 axis. Our motivation is to
study the effect of extra dimensions on the asymptotic behavior of the quantum
energy in the strong field limit (eB>>M^{2}), where M=1/R. We see that the weak
logarithmic growth of the quantum energy for four dimensions, is modified by a
rapid power growth in the case of the extra dimensions.Comment: 18 pages, 4 figures, 2 tables, several correction
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