18 research outputs found

    NLO corrections to ultra-high energy neutrino-nucleon scattering, shadowing and small x

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    We reconsider the Standard Model interactions of ultra-high energy neutrinos with matter. The next to leading order QCD corrections are presented for charged-current and neutral-current processes. Contrary to popular expectations, these corrections are found to be quite substantial, especially for very large (anti-) neutrino energies. Hence, they need to be taken into account in any search for new physics effects in high-energy neutrino interactions. In our extrapolation of the parton densities to kinematical regions as yet unexplored directly in terrestrial accelerators, we are guided by double asymptotic scaling in the large Q^2 and small Bjorken x region and to models of saturation in the low Q^2 and low x regime. The sizes of the consequent uncertainties are commented upon. We also briefly discuss some variables which are insensitive to higher order QCD corrections and are hence suitable in any search for new physics.Comment: 21 pages, LaTeX2e, uses JHEP3.cls (included), 8 ps files for figures published versio

    Antimatter Regions in the Early Universe and Big Bang Nucleosynthesis

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    We have studied big bang nucleosynthesis in the presence of regions of antimatter. Depending on the distance scale of the antimatter region, and thus the epoch of their annihilation, the amount of antimatter in the early universe is constrained by the observed abundances. Small regions, which annihilate after weak freezeout but before nucleosynthesis, lead to a reduction in the 4He yield, because of neutron annihilation. Large regions, which annihilate after nucleosynthesis, lead to an increased 3He yield. Deuterium production is also affected but not as much. The three most important production mechanisms of 3He are 1) photodisintegration of 4He by the annihilation radiation, 2) pbar-4He annihilation, and 3) nbar-4He annihilation by "secondary" antineutrons produced in anti-4He annihilation. Although pbar-4He annihilation produces more 3He than the secondary nbar-4He annihilation, the products of the latter survive later annihilation much better, since they are distributed further away from the annihilation zone.Comment: 15 pages, 9 figures. Minor changes to match the PRD versio

    Effects Of Fish Density On Spread Of Infectious Hematopoietic Necrosis Virus (IHNV) In Rainbow Trout, Oncorhynchus Mykiss

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    Rainbow trout (Oncorhynchus mykiss) were held at one of seven densities (8, 4, 0.63, 0.31, 0.16, 0.08 or 0.012 fish per liter) and challenged to the infectious hematopoietic necrosis virus (IHNV) by cohabitation with a single presumably infected donor fish. The trout were exposed to the IHNV-infected fish for 11 days to determine the effect of density on occurrence, spread and prevalence of the disease. The host density and IHNV prevalence were positively associated (r2 = 0.89, regression analysis) with no occurrence of the virus at the two lowest densities (0.08 and 0.012 fish/l). Host density, therefore, is a key factor in determining the incidence and magnitude of IHNV infection

    Curbing resource consumption using team-based feedback

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    This paper details a team-based feedback approach for reducing resource consumption. The approach uses paper printing within office environments as a case study. It communicates the print usage of each participant’s team rather than the participant’s individual print usage. Feedback is provided weekly via emails and contains normative information, along with eco-metrics and team-based comparative statistics. The approach was empirically evaluated to study the effectiveness of the feedback method. The experiment comprised of 16 people belonging to 4 teams with data on their print usage gathered over 58 weeks, using the first 30-35 weeks as a baseline. The study showed a significant reduction in individual printing with an average of 28%. The experiment confirms the underlying hypothesis that participants are persuaded to reduce their print usage in order to improve the overall printing behaviour of their teams. The research provides clear pathways for future research to qualitatively investigate our findings
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