843 research outputs found

    Essential role of the czc determinant for cadmium, cobalt and zinc resistance in Gluconacetobacter diazotrophicus PAl 5

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    The mechanisms of cadmium, cobalt and zinc resistance were characterized in the plant-growth-promoting bacterium Gluconacetobacter diazotrophicus PAl 5. The resistance level of the wild-type strain was evaluated through the establishment of minimum inhibitory concentrations (MIC) of the soluble compounds CdCl2·H2O, CoCl2·6H2O and ZnCl2. Gluconacetobacter diazotrophicus PAl 5 was resistant to high concentrations of Cd, Co and Zn, with MICs of 1.2, 20 and 20 mM, respectively. Screening of an insertion library from transposon EZ-Tn5<R6Kyori/KAN-2> in the presence of ZnO revealed that the mutant GDP30H3 was unable to grow in the presence of the compound. This mutant was also highly sensitive to CdCl2·H2O, CoCl2·6H2O and ZnCl2. Molecular characterization established that the mutation affected the czcA gene, which encodes a protein involved in metal efflux. In silico analysis showed that czcA is a component of the czcCBARS operon together with four other genes. This work provides evidence of the high tolerance of G. diazotrophicus PAl 5 to heavy metalsand that czc is a determinant for metal resistance in this bacterium. [Int Microbiol 2012; 15(2):69-78

    Selection index and molecular markers in reciprocal recurrent selection in maize

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    Reciprocal recurrent selection among full-sib families is one of the outstanding methodologies of maizeimprovement, since gains are possible in the per se and/or in cross populations. Here the selection index proposed by Smithand Hazel was used in the cited methodology; besides, an additional phase involving RAPD markers was introduced topreserve the genetic variability of the selected genotypes and identify contaminants before their recombination. Multivariatetechniques of grouping and discriminant analyses were used for this purpose, to assure the continuance of the improvementprogram and amplify the genetic distance between the populations Cimmyt and PiranĂŁo, which were used for an intervarietalhybrid. The molecular technique proved useful to identify contaminants and helpful in the choice of the genotypes to berecombined to maximize heterosis among populations. The technique can be included in recurrent selection programs, mainlythose that target the development of hybrids

    PrevalĂȘncia das principais complicaçÔes pĂłs-operatĂłrias em cirurgias cardĂ­acas: uma revisĂŁo sistemĂĄtica: Prevalence of major postoperative complications in cardiac surgeries: a systematic review

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    As complicaçÔes pĂłs-operatĂłrias em cirurgias cardĂ­acas sĂŁo comuns e contribuem para o aumento dos Ă­ndices de morbidade e mortalidade. Objetivo: identificar em trabalhos da literatura as principais complicaçÔes no pĂłs-operatĂłrio de cirurgias cardĂ­acas. Material e MĂ©todo: RevisĂŁo de literatura sobre as principais complicaçÔes no pĂłs-operatĂłrio de cirurgia cardĂ­aca. A busca foi realizada em outubro de 2022 nas fontes de dados: PubMed e Web of Science. Resultados: O processo de busca resultou em 2.744 documentos. ApĂłs primeira seleção 215 trabalhos tiveram os seus tĂ­tulos e resumos analisados para uma triagem inicial. A amostra final foi de 04 estudos. As complicaçÔes da cirurgia cardĂ­aca podem estar relacionadas a doenças prĂ©-existentes. Forma identificadas como complicaçÔes distĂșrbios de sono, hepatopatia cardĂ­aca pĂłs-operatĂłria, sĂ­ndrome da apneia e hipopneia obstrutiva do sono (SAHOS) e arritmias. ConclusĂ”es: As complicaçÔes apresentaram prevalĂȘncias diferentes nos estudos analisados e devem ser consideradas em mais estudos para melhor compreensĂŁo de fatores correlacionados auxiliando na sua prevenção e controle

    Combination of searches for heavy spin-1 resonances using 139 fb−1 of proton-proton collision data at s = 13 TeV with the ATLAS detector

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    A combination of searches for new heavy spin-1 resonances decaying into different pairings of W, Z, or Higgs bosons, as well as directly into leptons or quarks, is presented. The data sample used corresponds to 139 fb−1 of proton-proton collisions at = 13 TeV collected during 2015–2018 with the ATLAS detector at the CERN Large Hadron Collider. Analyses selecting quark pairs (qq, bb, , and tb) or third-generation leptons (Ï„Îœ and ττ) are included in this kind of combination for the first time. A simplified model predicting a spin-1 heavy vector-boson triplet is used. Cross-section limits are set at the 95% confidence level and are compared with predictions for the benchmark model. These limits are also expressed in terms of constraints on couplings of the heavy vector-boson triplet to quarks, leptons, and the Higgs boson. The complementarity of the various analyses increases the sensitivity to new physics, and the resulting constraints are stronger than those from any individual analysis considered. The data exclude a heavy vector-boson triplet with mass below 5.8 TeV in a weakly coupled scenario, below 4.4 TeV in a strongly coupled scenario, and up to 1.5 TeV in the case of production via vector-boson fusion

    Measurement and interpretation of same-sign W boson pair production in association with two jets in pp collisions at s = 13 TeV with the ATLAS detector

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    This paper presents the measurement of fducial and diferential cross sections for both the inclusive and electroweak production of a same-sign W-boson pair in association with two jets (W±W±jj) using 139 fb−1 of proton-proton collision data recorded at a centre-of-mass energy of √s = 13 TeV by the ATLAS detector at the Large Hadron Collider. The analysis is performed by selecting two same-charge leptons, electron or muon, and at least two jets with large invariant mass and a large rapidity diference. The measured fducial cross sections for electroweak and inclusive W±W±jj production are 2.92 ± 0.22 (stat.) ± 0.19 (syst.)fb and 3.38±0.22 (stat.)±0.19 (syst.)fb, respectively, in agreement with Standard Model predictions. The measurements are used to constrain anomalous quartic gauge couplings by extracting 95% confdence level intervals on dimension-8 operators. A search for doubly charged Higgs bosons H±± that are produced in vector-boson fusion processes and decay into a same-sign W boson pair is performed. The largest deviation from the Standard Model occurs for an H±± mass near 450 GeV, with a global signifcance of 2.5 standard deviations

    Measurement of the tt¯tt¯ production cross section in pp collisions at √s=13 TeV with the ATLAS detector

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    A measurement of four-top-quark production using proton-proton collision data at a centre-of-mass energy of 13 TeV collected by the ATLAS detector at the Large Hadron Collider corresponding to an integrated luminosity of 139 fb−1 is presented. Events are selected if they contain a single lepton (electron or muon) or an opposite-sign lepton pair, in association with multiple jets. The events are categorised according to the number of jets and how likely these are to contain b-hadrons. A multivariate technique is then used to discriminate between signal and background events. The measured four-top-quark production cross section is found to be 26+17−15 fb, with a corresponding observed (expected) significance of 1.9 (1.0) standard deviations over the background-only hypothesis. The result is combined with the previous measurement performed by the ATLAS Collaboration in the multilepton final state. The combined four-top-quark production cross section is measured to be 24+7−6 fb, with a corresponding observed (expected) signal significance of 4.7 (2.6) standard deviations over the background-only predictions. It is consistent within 2.0 standard deviations with the Standard Model expectation of 12.0 ± 2.4 fb
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