255 research outputs found

    Novel microbiological system for antibiotic detection in ovine milk

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    [EN] This article presents a microbiological system composed of a " BT" bioassay (Beta-lactams and Tetracyclines) and a " QS" bioassay (Quinolones and Sulfonamides). The " BT" bioassay contains spores of Geobacillus stearothermophilus, bromocresol purple and cloramphenicol in a culture medium (incubation time: 2.45h), while the " QS" bioassay uses spores of Bacillus subtilis, trifenyltetrazolium - toluidine blue and trimethoprim in a suitable culture medium (incubation time: 5.5h). The detection capability (CC ß) of 27 antimicrobial agents in ovine milk were determined by logistic regression models. Thus, the " BT" bioassay detects amoxycillin, ampicillin, penicillin " G" , cloxacillin, oxacillin, cephalexin, cefoperazone, ceftiofur, chlortetracycline, oxytetracycline, tetracycline, neomycin, gentamycin and tylosin, while " QS" bioassay detects: ciprofloxacin, enrofloxacin, marbofloxacin, sulfadiazine, sulfadimethoxine, sulfamerazine, sulfamethazine, sulfamethoxazole, sulfathiazole, erythromycin, lincomycin and spiramycin at levels close to their respective Maximum Residue Limits. The simultaneous use of both bioassays detects a large number of antibiotics in milk given each method's adequate complementary sensitivity. © 2011 Elsevier B.V..This research work has been carried out as part of the CAI+D'09/12 Projects (No. 033-173 Res. H.C.D. No. 100/09, Universidad Nacional del Litoral, Santa Fe, Argentina) and AGL2009-11524 (Ministry of Science and Innovation, Spain).Nagel, OG.; Beltrán Martínez, MC.; Molina Pons, MP.; Lisandro Althaus, R. (2012). Novel microbiological system for antibiotic detection in ovine milk. Small Ruminant Research. 102(1):26-31. https://doi.org/10.1016/j.smallrumres.2011.11.018S2631102

    Algunes reflexions entorn de la conceptualització de la infància i adolescència en risc social a l'Estat espanyol

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    L'article realitza una aproximació a les interpretacions del concepte de risc social de la infancia per part de diversos autors d'àmbit estatal, tenint també en compte els marcs legals català i espanyol. Pretén aclarir quins són els criteris valoratius emprats, tant des de l'àmbit acadèmic com del professional, per interpretar les categoritzacions de la infància i l'adolescència en processos de dificultat i precarietat social. Des d'aquesta perspectiva, s'hi analitza l'estreta relació entre factors de risc, desemparament i marginació. S'hi rebutgen les interpretacions que responsabilitzen el propi menor de la desadaptació, i s'hi defensa la hipótesi de la necessitat d'una intervenció socioeducativa que treballi per una disminució dels factors de risc en el propi medi, mantenint el seu protagonisme en aquest procés.This article is an approach to the different acceptances of the concept social risk as well as the terms neglect and maladjustment, based on the reflections made by different authors and both statal and autonomous legal framework. It intends to clarify which are the criteria of values used in academic and professional ambits in order to understand the categoriesfound in the fields of childhood and adolescence in difficult and precarious conditions. The strong relation between risk factors, neglect and margination has been analysed from this point of view. In the same way the interpretations that hold the minor himself responsible for his maladjustment are rejected and the author defends the necessity of a socio-educational intervention, which reduces the risk factors in the child's environment, and the need of paying close attention to the child's main role in this process.El artículo realiza una aproximación a las interpretaciones del concepto de riesgo social de la infancia por parte de diversos autores de ámbito estatal, teniendo también en cuenta los marcos legales catalán y español. Pretende aclarar cuáles son los criterios valorativos utilizados, tanto desde el ámbito academico como profesional, para interpretar las categorizaciones de la infancia en procesos de dificultad y precariedad. Desde esta perspectiva, se analiza la estrecha relación entre factores de riesgo, desamparamiento y marginación. Se rechazan las interpretaciones que responsabilizan al propio menor de la desadaptación y se defiende la hipótesis de la necesidad de una intervención socioeducativa que trabaje para una disminución de los factores de riesgo en el propio medio, manteniendo su protagonismo en este proceso

    Study of CP violation in Dalitz-plot analyses of B0 --> K+K-KS, B+ --> K+K-K+, and B+ --> KSKSK+

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    We perform amplitude analyses of the decays B0K+KKS0B^0 \to K^+K^-K^0_S, B+K+KK+B^+ \rightarrow K^+K^-K^+, and B+KS0KS0K+B^+ \to K^0_S K^0_S K^+, and measure CP-violating parameters and partial branching fractions. The results are based on a data sample of approximately 470×106470\times 10^6 BBˉB\bar{B} decays, collected with the BABAR detector at the PEP-II asymmetric-energy BB factory at the SLAC National Accelerator Laboratory. For B+K+KK+B^+ \to K^+K^-K^+, we find a direct CP asymmetry in B+ϕ(1020)K+B^+ \to \phi(1020)K^+ of ACP=(12.8±4.4±1.3)A_{CP}= (12.8\pm 4.4 \pm 1.3)%, which differs from zero by 2.8σ2.8 \sigma. For B0K+KKS0B^0 \to K^+K^-K^0_S, we measure the CP-violating phase βeff(ϕ(1020)KS0)=(21±6±2)\beta_{\rm eff} (\phi(1020)K^0_S) = (21\pm 6 \pm 2)^\circ. For B+KS0KS0K+B^+ \to K^0_S K^0_S K^+, we measure an overall direct CP asymmetry of ACP=(45+4±2)A_{CP} = (4 ^{+4}_{-5} \pm 2)%. We also perform an angular-moment analysis of the three channels, and determine that the fX(1500)f_X(1500) state can be described well by the sum of the resonances f0(1500)f_0(1500), f2(1525)f_2^{\prime}(1525), and f0(1710)f_0(1710).Comment: 35 pages, 68 postscript figures. v3 - minor modifications to agree with published versio

    Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

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    A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

    Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC

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    Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the anti-kt algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. Rcp varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables, submitted to Physics Letters B. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02

    Measurement of the View the tt production cross-section using eμ events with b-tagged jets in pp collisions at √s = 13 TeV with the ATLAS detector

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    This paper describes a measurement of the inclusive top quark pair production cross-section (σtt¯) with a data sample of 3.2 fb−1 of proton–proton collisions at a centre-of-mass energy of √s = 13 TeV, collected in 2015 by the ATLAS detector at the LHC. This measurement uses events with an opposite-charge electron–muon pair in the final state. Jets containing b-quarks are tagged using an algorithm based on track impact parameters and reconstructed secondary vertices. The numbers of events with exactly one and exactly two b-tagged jets are counted and used to determine simultaneously σtt¯ and the efficiency to reconstruct and b-tag a jet from a top quark decay, thereby minimising the associated systematic uncertainties. The cross-section is measured to be: σtt¯ = 818 ± 8 (stat) ± 27 (syst) ± 19 (lumi) ± 12 (beam) pb, where the four uncertainties arise from data statistics, experimental and theoretical systematic effects, the integrated luminosity and the LHC beam energy, giving a total relative uncertainty of 4.4%. The result is consistent with theoretical QCD calculations at next-to-next-to-leading order. A fiducial measurement corresponding to the experimental acceptance of the leptons is also presented

    Search for strong gravity in multijet final states produced in pp collisions at √s=13 TeV using the ATLAS detector at the LHC

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    A search is conducted for new physics in multijet final states using 3.6 inverse femtobarns of data from proton-proton collisions at √s = 13TeV taken at the CERN Large Hadron Collider with the ATLAS detector. Events are selected containing at least three jets with scalar sum of jet transverse momenta (HT) greater than 1TeV. No excess is seen at large HT and limits are presented on new physics: models which produce final states containing at least three jets and having cross sections larger than 1.6 fb with HT > 5.8 TeV are excluded. Limits are also given in terms of new physics models of strong gravity that hypothesize additional space-time dimensions

    Search for TeV-scale gravity signatures in high-mass final states with leptons and jets with the ATLAS detector at sqrt [ s ] = 13TeV

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    A search for physics beyond the Standard Model, in final states with at least one high transverse momentum charged lepton (electron or muon) and two additional high transverse momentum leptons or jets, is performed using 3.2 fb−1 of proton–proton collision data recorded by the ATLAS detector at the Large Hadron Collider in 2015 at √s = 13 TeV. The upper end of the distribution of the scalar sum of the transverse momenta of leptons and jets is sensitive to the production of high-mass objects. No excess of events beyond Standard Model predictions is observed. Exclusion limits are set for models of microscopic black holes with two to six extra dimensions

    Operation and performance of the ATLAS semiconductor tracker

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    The semiconductor tracker is a silicon microstrip detector forming part of the inner tracking system of the ATLAS experiment at the LHC. The operation and performance of the semiconductor tracker during the first years of LHC running are described. More than 99% of the detector modules were operational during this period, with an average intrinsic hit efficiency of (99.74±0.04)%. The evolution of the noise occupancy is discussed, and measurements of the Lorentz angle, δ-ray production and energy loss presented. The alignment of the detector is found to be stable at the few-micron level over long periods of time. Radiation damage measurements, which include the evolution of detector leakage currents, are found to be consistent with predictions and are used in the verification of radiation background simulations

    Measurement of the correlation between flow harmonics of different order in lead-lead collisions at √sNN = 2.76 TeV with the ATLAS detector

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    Correlations between the elliptic or triangular flow coefficients vm (m=2 or 3) and other flow harmonics vn (n=2 to 5) are measured using √sNN=2.76 TeV Pb+Pb collision data collected in 2010 by the ATLAS experiment at the LHC, corresponding to an integrated luminosity of 7 μb−1. The vm−vn correlations are measured in midrapidity as a function of centrality, and, for events within the same centrality interval, as a function of event ellipticity or triangularity defined in a forward rapidity region. For events within the same centrality interval, v3 is found to be anticorrelated with v2 and this anticorrelation is consistent with similar anticorrelations between the corresponding eccentricities, ε2 and ε3. However, it is observed that v4 increases strongly with v2, and v5 increases strongly with both v2 and v3. The trend and strength of the vm−vn correlations for n=4 and 5 are found to disagree with εm−εn correlations predicted by initial-geometry models. Instead, these correlations are found to be consistent with the combined effects of a linear contribution to vn and a nonlinear term that is a function of v22 or of v2v3, as predicted by hydrodynamic models. A simple two-component fit is used to separate these two contributions. The extracted linear and nonlinear contributions to v4 and v5 are found to be consistent with previously measured event-plane correlations
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