21,010 research outputs found

    Four-gluon scattering at three loops, infrared structure and Regge limit

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    We compute the three-loop four-gluon scattering amplitude in maximally supersymmetric Yang-Mills theory, including its full color dependence. Our result is the first complete computation of a non-planar four-particle scattering amplitude to three loops in four-dimensional gauge theory and consequently provides highly non-trivial data for the study of non-planar scattering amplitudes. We present the amplitude as a Laurent expansion in the dimensional regulator to finite order, with coefficients composed of harmonic poly-logarithms of uniform transcendental weight, and simple rational prefactors. Our computation provides an independent check of a recent result for three-loop corrections to the soft anomalous dimension matrix that predicts the general infrared singularity structure of massless gauge theory scattering amplitudes. Taking the Regge limit of our result, we determine the three-loop gluon Regge trajectory. We also find agreement with very recent predictions for sub-leading logarithms

    What do cells actually want?

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    Genome-scale models require an objective function representing what an organism strives for. A method has been developed to infer this fundamental biological function from data.Please see related Research article: www.dx.doi.org/10.1186/s13059-016-0968-2

    East African pholcid spiders: an overview, with descriptions of eight new species (Araneae, Pholcidae)

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    This paper summarizes current knowledge about East African pholcids. East Africa is defined as the area from 12°S to 5°N and from 28° to 42°E, including all of Uganda, Kenya, Burundi, Rwanda, and Tanzania. An annotated list of the 15 genera and 87 species recorded from this area is given, together with distribution maps and an identification key to genera. Most East African species (90%) belong to one of only six genera: Buitinga Huber, 2003 (21 species); Smeringopus Simon, 1890 (18); Pholcus Walckenaer, 1805 (17); Spermophora Hentz, 1841 (12); Leptopholcus Simon, 1893 (5) and Quamtana Huber, 2003 (4). Eight species for which DNA sequence data have been published recently are newly described: Buitinga batwa sp. nov., B. wataita sp. nov., Spermophora mau sp. nov., S. maathaiae sp. nov., S. bukusu sp. nov., S. kirinyaga sp. nov., S. kyambura sp. nov. and Quamtana nyahururu sp. nov. Crossopriza johncloudsleyi Deeleman-Reinhold & van Harten, 2001, previously only known from Yemen, is redescribed based on specimens from Kenya. Additional new records are given for 21 previously described species

    Prediction of light aircraft interior sound pressure level using the room equation

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    The room equation is investigated for predicting interior sound level. The method makes use of an acoustic power balance, by equating net power flow into the cabin volume to power dissipated within the cabin using the room equation. The sound power level transmitted through the panels was calculated by multiplying the measured space averaged transmitted intensity for each panel by its surface area. The sound pressure level was obtained by summing the mean square sound pressures radiated from each panel. The data obtained supported the room equation model in predicting the cabin interior sound pressure level

    Contact urticaria to giraffe hair

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    Background: Immediate-type hypersensitivity to animal proteins is a common problem in people occupationally exposed to animals. Methods: A 19-year-old female working as a voluntary zookeeper in her off-time suffered from hives on her forearms following contact to the fur of a giraffe. For diagnostic evaluation, skin prick tests, assessment of specific serum IgE antibodies, and basophil activation tests were performed. Results: Skin prick tests with a standard series of common aeroallergens were positive for various pollens. Prick testing with native materials was positive for extracts of hair from two different giraffe subspecies in the patient, but not in control subjects. By CAP-FEIA, no specific serum IgE antibodies to dander of a large variety of animals were found in the patient. In the basophil activation test, expression of the activation marker CD63 was induced by extract of giraffe hair on the cells from the patient, but not on those from unaffected controls. Conclusions: This patient suffers from an `exotic' immediate-type contact allergy to giraffe hair. Copyright (C) 2005 S. Karger AG, Basel
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