22 research outputs found

    Presencia de paratuberculosis en rumiantes en el estado de Zacatecas a través de estudio histopatológico

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    This study aimed to determine the presence of histopathological lesions suggestive of Mycobacterium avium subspecies paratuberculosis in ruminants with clinical field manifestations of paratuberculosis in the Mexican state of Zacatecas. Sixteen sheep, five goats, and four cattle from the municipalities of Morelos, Enrique Estrada, Jerez de García Salinas, Víctor Rosales, Fresnillo, Saín Alto, and Tepetongo were examined. The animals ranged in age from 5 weeks to 4 years. At necropsy, representative samples were taken from organs such as the small intestine, ileocecal valve, and mesenteric lymph nodes, for the routine histological technique of hematoxylin and eosin (HE). Subsequently, the Ziehl-Neelsen (ZN) technique was performed. It was observed that 56% of the animals were positive for acid-fast bacilli (AFB), compatible with Mycobacterium avium subspecies paratuberculosis. Eighty percent of the cases came from goats and 62.5% from sheep. 58.3% of females of both species showed lesions suggestive of paratuberculosis, and there was no significant difference in males. The lesions observed in the intestine were: proliferative enteritis in 78.6% of the cases, in the jejunum, enteritis, and necrosis in 21.4% of the cases, in the ileum, proliferative enteritis in 100% of the cases and 57.1% of lymph nodes were lymphadenomegalic and 50% of the cases in of the cases contained an inflammatory infiltrate in. In the state of Zacatecas, there is complete lack of studies that have detected the presence of paratuberculosis in any species, despite its economic and health importance.El presente estudio tuvo como objetivo determinar la presencia de lesiones histopatológicas sugestivas de Mycobacterium avium subespecie paratuberculosis en rumiantes con manifestaciones clínicas de campo de paratuberculosis en el estado mexicano de Zacatecas. Se examinaron 16 ovinos, 5 caprinos y 4 bovinos de los municipios de Morelos, Enrique Estrada, Jerez de García Salinas, Víctor Rosales, Fresnillo, Saín Alto y Tepetongo. La edad de los animales osciló entre 5 semanas y 4 años. En la necropsia se tomaron muestras representativas de órganos tales como intestino delgado, válvula ileocecal y ganglios linfáticos mesentéricos, para la técnica histológica de rutina de hematoxilina y eosina (HE). Posteriormente, se realizó la tinción de Ziehl-Neelsen (ZN). Se observó que el 56% de los animales eran positivos para bacilos ácido-alcohol resistentes (BAAR), compatibles con Mycobacterium avium subespecie paratuberculosis. El 80% de casos procedían de cabras y el 62.5% de ovejas. El 58.3% de las hembras de ambas especies presentaban lesiones sugestivas de paratuberculosis, y no había diferencias significativas en los machos. Las lesiones observadas en el intestino fueron: enteritis proliferativa en el 78.6% de los casos, en el yeyuno, enteritis y necrosis en el 21.4% de los casos, en el íleon, enteritis proliferativa en el 100% de los casos y el 57.1% de los ganglios linfáticos eran linfadenomegálicos y el 50% de los casos contenían un infiltrado inflamatorio. En el estado de Zacatecas se carece por completo de estudios que hayan detectado la presencia de paratuberculosis en alguna especie, a pesar de su importancia económica y sanitaria

    Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

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    A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

    Search for single production of vector-like quarks decaying into Wb in pp collisions at s=8\sqrt{s} = 8 TeV with the ATLAS detector

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    Measurements of top-quark pair differential cross-sections in the eμe\mu channel in pppp collisions at s=13\sqrt{s} = 13 TeV using the ATLAS detector

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    Measurement of the W boson polarisation in ttˉt\bar{t} events from pp collisions at s\sqrt{s} = 8 TeV in the lepton + jets channel with ATLAS

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    Measurement of the charge asymmetry in top-quark pair production in the lepton-plus-jets final state in pp collision data at s=8TeV\sqrt{s}=8\,\mathrm TeV{} with the ATLAS detector

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    Charged-particle distributions at low transverse momentum in s=13\sqrt{s} = 13 TeV pppp interactions measured with the ATLAS detector at the LHC

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    ATLAS Run 1 searches for direct pair production of third-generation squarks at the Large Hadron Collider

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    Measurement of the bbb\overline{b} dijet cross section in pp collisions at s=7\sqrt{s} = 7 TeV with the ATLAS detector

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    Search for dark matter in association with a Higgs boson decaying to bb-quarks in pppp collisions at s=13\sqrt s=13 TeV with the ATLAS detector

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