363 research outputs found

    Twisted Backgrounds, PP-Waves and Nonlocal Field Theories

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    We study partially supersymmetric plane-wave like deformations of string theories and M-theory on brane backgrounds. These deformations are dual to nonlocal field theories. We calculate various expectation values of configurations of closed as well as open Wilson loops and Wilson surfaces in those theories. We also discuss the manifestation of the nonlocality structure in the supergravity backgrounds. A plane-wave like deformation of little string theory has also been studied.Comment: 46 pages, changed to JHEP forma

    A lattice model for the kinetics of rupture of fluid bilayer membranes

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    We have constructed a model for the kinetics of rupture of membranes under tension, applying physical principles relevant to lipid bilayers held together by hydrophobic interactions. The membrane is characterized by the bulk compressibility (for expansion), the thickness of the hydrophobic part of the bilayer, the hydrophobicity and a parameter characterizing the tail rigidity of the lipids. The model is a lattice model which incorporates strain relaxation, and considers the nucleation of pores at constant area, constant temperature, and constant particle number. The particle number is conserved by allowing multiple occupancy of the sites. An equilibrium ``phase diagram'' is constructed as a function of temperature and strain with the total pore surface and distribution as the order parameters. A first order rupture line is found with increasing tension, and a continuous increase in proto-pore concentration with rising temperature till instability. The model explains current results on saturated and unsaturated PC lipid bilayers and thicker artificial bilayers made of diblock copolymers. Pore size distributions are presented for various values of area expansion and temperature, and the fractal dimension of the pore edge is evaluated.Comment: 15 pages, 8 figure

    Nematodes Affecting Soybean and Sustainable Practices for Their Management

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    Plant‐parasitic nematodes are one of the limiting factors for soybean production worldwide. Overall, plant‐parasitic nematodes alone cause an estimated annual crop loss of $78 billion worldwide and an average crop yield loss of 10–15%. This imposes a challenge to sustainable production of food worldwide, since there has been increasing demand for food supply and food security. Unsustainable cropping production systems with monocultures, intensive use of soils and expansion of crops to newly opened areas have intensified problems associated with new pests and diseases. Thus, finding and applying sustainable methods to control diseases associated with soybean are in current need. Over hundred nematode species, comprising fifty genera, have been reported in association with soybean. Of these, the root‐knot nematode Meloidogyne spp., cyst nematode Heterodera glycines, lesion nematode Pratylenchus brachyurus and the reniform nematode Rotylenchulus reniformis are major nematode species limiting soybean production. Here, we report an up‐to‐date literature review on the biology, symptoms, damage and control methods used for these nematodes species. Additionally, unusual and emergent nematode species affecting soybean are discussed

    Measurement of the mass difference between top quark and antiquark in pp collisions at root s=8 TeV

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    Peer reviewe

    Enfermidades de cutias (Dasyprocta aguti) criadas em cativeiro diagnosticadas pelo exame anatomopatológico

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    O exame necroscópico é especialmente útil no diagnóstico de enfermidades em animais silvestres. Em muitas ocasiões, as manifestações clínicas não são características como em animais domésticos, sendo frequente a ocorrência de óbitos em animais assintomáticos. Este trabalho objetivou realizar um estudo retrospectivo sobre as doenças de cutias diagnosticadas pelo Laboratório de Patologia Veterinária da Universidade Federal Rural do Semi-Árido, através do exame anatomopatológico no período de 2006 a 2009. Em 32 cutias submetidas à necropsia, as percentagens das enfermidades diagnosticadas foram: morte perinatal pelo complexo inanição/hipotermia (21,6%), urolitíase obstrutiva (6,24%), distocia (6,24%), obstrução do ceco por areia - sablose (6,24%), intussuscepção (3,20%), fecaloma (3,20%) e obstrução do esôfago (3,20%). Dezesseis (16) animais permaneceram sem diagnóstico, dos quais nove (28,48%) apresentavam avançado estado autolítico e em sete (21,60%) não foram observadas lesões macro e microscópicas compatíveis com nenhuma enfermidade. Este artigo apresenta relatos de doenças ainda não descritas em cutias e seus resultados poderão produzir literatura sobre os aspectos patológicos destas enfermidades nessa espécie.Necroscopic examination is remarkably useful to diagnose wild animal's diseases. In several occasions the clinical signs are not charactheristic as in domestic animals and the occurrence of death in asymptomatic animals is frequent. Thus, the present work aimed to accomplish a retrospective study on agouti diseases diagnosed by pathological examination in the Laboratory of Veterinary Pathology, Federal Rural University of the Semi-arid, through January 2006 to December 2006. In 32 agoutis submitted to the necropsy, the percentage of diagnosed diseases was: perinatal death due hypothermia/ inanition complex (21.6%), obstructive urolithiasis (6.24%), dystocia (6.24%), cecum sablosis (6.24%), intussusceptions (3.20%), fecaloma (3.20%) and esophagus obstruction (3.20%). A total of 16 (50.08%) animals remained undiagnosed in which nine (28.48%) showed advanced autolysis and seven (21.60%) agouti had none macroscopic or microscopic lesions compatible with any disease. The present article presents reports of some diseases not yet diagnosed in agoutis and these results may produce literature review about the pathologic aspects of these diseases in this species

    Foot rot and other foot diseases of goat and sheep in the semiarid region of northeastern Brazil

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    This paper reports the occurrence and epidemiology of outbreaks of foot rot and other foot diseases in goats and sheep in the semiarid region of Paraíba, northeastern Brazil. Four farms were inspected for the presence of foot lesion in sheep and goats and for environmental conditions, general hygiene, pastures, and disease control measures. The prevalence of foot lesions was 19.41% (170/876) in sheep and 17.99% (52/289) in goats, ranging between 5.77% and 33.85% in different farms. Foot rot was the most common disease, affecting 12.1% of the animals examined (141/1165), but with significantly higher (p<0.05) prevalence in sheep (13.69%) than in goats (7.27%). The frequency of malignant foot rot was also significantly lower (p<0.05) in goats (9.53%) than in the sheep (40.83%). On one farm, Dorper sheep showed significantly higher (p<0.05) prevalence of foot rot (17.5%) than Santa Inês sheep (6.79%), and the number of digits affected was also higher in the former. Dichelobacter nodosus and Fusobacterium necrophorum were isolated from cases of foot rot. White line disease was found in 3.95% of the animals, sole ulcers in 1.29%, foot abscess in 1.03% and hoof overgrowth in 0.5%. The high rainfall at the time of occurrence, grazing in wetlands, clay soils with poor drainage, presence of numerous stony grounds, closure of the flocks in pens at night, and introduction of affected animals were considered predisposing factors for the occurrence of foot diseases

    Raiva em bovinos na Região Sul do Rio Grande do Sul: epidemiologia e diagnóstico imuno-histoquímico

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    Foi realizado um estudo retrospectivo de casos de raiva paralítica em bovinos na área de influência do Laboratório Regional de Diagnóstico (LRD) da Faculdade de Veterinária, Universidade Federal de Pelotas (UFPel), ocorridos em 1978-2007. Foram estudados também 11 surtos de raiva observados em 2008-2010, na mesma região. Neste período morreram 42 animais de um total de 686 sob risco. A idade dos animais foi de 1-6 anos e o curso clínico de 4-14 dias. No estudo retrospectivo de 1978-2007 foram identificados 77 surtos ou casos isolados de raiva paralítica em bovinos. A morbidade em todos os surtos diagnosticados em 1978-2010 variou de 0,37% a 20%. Vinte e quatro casos ocorreram no outono, sete na primavera, 14 no verão e 16 no inverno. O diagnóstico foi realizado pela epidemiologia, sinais clínicos e lesões histológicas observadas. No estudo dos casos de raiva paralítica em bovinos ocorridos a partir de 2008, o diagnóstico foi confirmado pela técnica de imuno-histoquímica utilizando anticorpo policlonal anti-virus rábico. Em dois destes casos não foi observada meningoencefalite não-supurativa, porém a imuno-histoquímica demonstrou a presença do antígeno viral. Esta técnica é uma importante ferramenta para o diagnóstico de raiva, devendo ser utilizada em todos os casos suspeitos nos quais não se evidenciam lesões de encefalite
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