516 research outputs found

    Inconsistency in serial choice decision and motor reaction times dissociate in younger and older adults

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    Intraindividual variability (inconsistency) in reaction time (RT) latencies was investigated in a group of younger (M = 25.46 years) and older (M = 69.29 years) men. Both groups performed 300 trials in 2-, 4-, and 8-choice RT conditions where RTs for decision and motor components of the task were recorded separately. A dissociation was evident in that inconsistency was greater in older adults for decision RTs when task demands relating to the number of choices and fatigue arising from time-on-task were high. For younger persons, a weak trend toward greater inconsistency in motor RTs was evident. The results are consistent with accounts suggesting that inconsistency in neurobiological mechanisms increases with age, and that attentional lapses or fluctuations in executive control contribute to RT inconsistency

    SNP associations and genetic-parameter estimation for nose and hoof pigmentation in Corriedale sheep

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    Published Online 7/6/23 OnlinePublContext. Quantity and quality of both meat and wool are important for selection programs of the dual-purpose Corriedale sheep. In Corriedales, black pigmentation of nose skin and hooves is preferred as part of the breed standard. However, within the breed, pigmentation can vary from none to complete pigmentation. Aims. The aim was to discover single-nucleotide polymorphisms (SNPs) and genes associated with nose and hoof pigmentation and to estimate genetic parameters of nose and hoof pigmentation, wool traits and meat traits. Methods. The phenotype and genotype data on Corriedale lambs (n = 764) produced from 44 sires (12 studs) and 300 ewes in 2017–2019 were used in this study. Lambs were slaughtered at 6–7 months of age. Nose pigmentation and hoof pigmentation were scored on a five-point scale, where no pigmentation was scored 0 and complete pigmentation was scored 5. Wool-and meat-quality traits were measured, including greasy fleece weight, fibre diameter, weaning weight, hot standard carcass weight and intramuscular fat percentage. The lambs were genotyped with the GGPOvine50K SNP chip. A genome-wide association study (GWAS) was conducted. Genetic parameters and bivariate analyses were estimated using ASReml-R. Results. The lambs had a mean nose-pigmentation score of 3.69 and hoof-pigmentation score of 4.12. The nose pigmentation (h2 = 0.58) and hoof pigmentation (h2 = 0.51) were highly heritable and highly correlated (rG = 0.73). The GWAS identified a genome-wide significant SNP (OAR19_33278780.1) associated with nose pigmentation (q-value = 0.04). This SNP is positioned in a known pigmentation gene, melanocyte-inducing transcription factor (MITF ). The same SNP was the sixth-most associated SNP for hoof pigmentation but did not reach significance level. OAR19_33278780.1 also had a significant effect on back conformation and weaning weight. Conclusions. The results of these analyses have provided information and an understanding of the genetics for pigmentation of nose and hooves in Corriedale sheep. Implications. Nose and hoof pigmentation are highly genetically correlated with each other, but with no negative effects on production traits.J. E. Aldersey, M. S. Khatkar, P. J. Blackwood, C. E. Blackwood, J. M. Pitchford, H. Gordon, S. C. Welsh and W. S. Pitchfor

    The University of Michigan cyclotron facility for research in nuclear structure

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    A number of improvements have been made in The University of Michigan 83" sector focused cyclotron since its original construction. The reasons for the changes and the resulting improvement in the production of stable high-quality beams for nuclear research are described. A brief description of the total facility for research in nuclear structure is given.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22317/1/0000762.pd

    Search for Charmless Two-body Baryonic Decays of B Mesons

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    We report the results of a search for the rare baryonic decays B0ppˉB^0 \to p\bar{p}, ΛΛˉ\Lambda\bar{\Lambda}, and B+pΛˉB^+ \to p\bar{\Lambda}. The analysis is based on a data set of 31.7×106BBˉ31.7\times 10^6 B\bar{B} events collected by the Belle detector at the KEKB e+ee^+e^- collider. No statistically significant signals are found, and we set branching fraction upper limits B(B0ppˉ)<1.2×106{\mathcal B}(B^0 \to p\bar{p}) < 1.2 \times 10^{-6}, B(B0ΛΛˉ)<1.0×106{\mathcal B}(B^0 \to \Lambda\bar{\Lambda}) < 1.0 \times 10^{-6}, and B(B+pΛˉ)<2.2×106{\mathcal B}(B^+ \to p\bar{\Lambda}) < 2.2 \times 10^{-6} at the 90% confidence level.Comment: 6 pages, 4 figures and 1 table. Submitted to Phys. Rev. D Rapid Communication

    Search for Direct CP Violation in B -> K pi Decays

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    We search for direct CP violation in flavor specific B -> K pi decays by measuring the rate asymmetry between charge conjugate modes. The search is performed on a data sample of 11.1 million B B bar events recorded on the Upsilon(4S) resonance by the Belle experiment at KEKB. We measure 90% confidence intervals in the partial rate asymmetry A_CP of -0.25 < A_CP(K-/+ pi+/-) < 0.37, -0.40 < A_CP(K-/+ pi^0) < 0.36, and -0.53 < A_CP(K^0 pi-/+) < 0.82. By combining the K-/+ pi+/- and K-/+ pi^0 final states, we conclude that -0.22 < A_CP[K-/+(pi+/- + pi^0)] < 0.25 at the 90% confidence level.Comment: Submitted to PRD Rapid Communication

    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 polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

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    This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio

    Observation of a new chi_b state in radiative transitions to Upsilon(1S) and Upsilon(2S) at ATLAS

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    The chi_b(nP) quarkonium states are produced in proton-proton collisions at the Large Hadron Collider (LHC) at sqrt(s) = 7 TeV and recorded by the ATLAS detector. Using a data sample corresponding to an integrated luminosity of 4.4 fb^-1, these states are reconstructed through their radiative decays to Upsilon(1S,2S) with Upsilon->mu+mu-. In addition to the mass peaks corresponding to the decay modes chi_b(1P,2P)->Upsilon(1S)gamma, a new structure centered at a mass of 10.530+/-0.005 (stat.)+/-0.009 (syst.) GeV is also observed, in both the Upsilon(1S)gamma and Upsilon(2S)gamma decay modes. This is interpreted as the chi_b(3P) system.Comment: 5 pages plus author list (18 pages total), 2 figures, 1 table, corrected author list, matches final version in Physical Review Letter
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