334 research outputs found

    Caffeine and Placebo Improved Maximal Exercise Performance Despite Unchanged Motor Cortex Activation and Greater Prefrontal Cortex Deoxygenation

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    Caffeine (CAF) is an ergogenic aid used to improve exercise performance. Independent studies have suggested that caffeine may have the ability to increase corticospinal excitability, thereby decreasing the motor cortex activation required to generate a similar motor output. However, CAF has also been suggested to induce a prefrontal cortex (PFC) deoxygenation. Others have suggested that placebo (PLA) may trigger comparable effects to CAF, as independent studies found PLA effects on motor performance, corticospinal excitability, and PFC oxygenation. Thus, we investigated if CAF and CAF-perceived PLA may improve motor performance, despite the likely unchanged MC activation and greater PFC deoxygenation. Nine participants (26.4 ± 4.8 years old, VO2MAX of 42.2 ± 4.6 mL kg-1 min-1) performed three maximal incremental tests (MITs) in control (no supplementation) and ∼60 min after CAF and PLA ingestion. PFC oxygenation (near-infrared spectroscopy at Fp1 position), MC activation (EEG at Cz position) and vastus lateralis and rectus femoris muscle activity (EMG) were measured throughout the tests. Compared to control, CAF and PLA increased rectus femoris muscle EMG (P = 0.030; F = 2.88; d = 0.84) at 100% of the MIT, and enhanced the peak power output (P = 0.006; F = 12.97; d = 1.8) and time to exhaustion (P = 0.007; F = 12.97; d = 1.8). In contrast, CAF and PLA did not change MC activation, but increased the PFC deoxygenation as indicated by the lower O2Hb (P = 0.001; F = 4.68; d = 1.08) and THb concentrations (P = 0.01; F = 1.96; d = 0.7) at 80 and 100% the MIT duration. These results showed that CAF and CAF-perceived PLA had the ability to improve motor performance, despite unchanged MC activation and greater PFC deoxygenation. The effectiveness of CAF as ergogenic aid to improve MIT performance was challenged

    Comprehensive study of reaction mechanisms for the Be9+Sm144 system at near- and sub-barrier energies

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    The delayed x-ray detection technique was used to measure complete and incomplete fusion cross sections for the 9Be+144Sm^{9}\mathrm{Be}+^{144}\mathrm{Sm} reaction at sub- and near-barrier energies. Elastic and inelastic scattering for this system were also measured. Reaction cross sections were derived and the transfer cross sections of one neutron were calculated. The suppression of complete fusion above the barrier, of the order of 10%, is attributed to 9Be^{9}\mathrm{Be} breakup and is considerably smaller than the value of 30% found for the 9Be+208Pb^{9}\mathrm{Be}+^{208}\mathrm{Pb} system

    Standalone vertex finding in the ATLAS muon spectrometer

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    A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at √s = 7 TeV collected with the ATLAS detector at the LHC during 2011

    Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC

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    Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H →γ γ, H → Z Z∗ →4l and H →W W∗ →lνlν. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV, corresponding to an integrated luminosity of about 25 fb−1. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined fits probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson

    Hunt for new phenomena using large jet multiplicities and missing transverse momentum with ATLAS in 4.7 fb−1 of √s=7 TeV proton-proton collisions

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    Results are presented of a search for new particles decaying to large numbers of jets in association with missing transverse momentum, using 4.7 fb−1 of pp collision data at s√=7TeV collected by the ATLAS experiment at the Large Hadron Collider in 2011. The event selection requires missing transverse momentum, no isolated electrons or muons, and from ≥6 to ≥9 jets. No evidence is found for physics beyond the Standard Model. The results are interpreted in the context of a MSUGRA/CMSSM supersymmetric model, where, for large universal scalar mass m 0, gluino masses smaller than 840 GeV are excluded at the 95% confidence level, extending previously published limits. Within a simplified model containing only a gluino octet and a neutralino, gluino masses smaller than 870 GeV are similarly excluded for neutralino masses below 100 GeV

    The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe

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    The preponderance of matter over antimatter in the early Universe, the dynamics of the supernova bursts that produced the heavy elements necessary for life and whether protons eventually decay --- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our Universe, its current state and its eventual fate. The Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed plan for a world-class experiment dedicated to addressing these questions. LBNE is conceived around three central components: (1) a new, high-intensity neutrino source generated from a megawatt-class proton accelerator at Fermi National Accelerator Laboratory, (2) a near neutrino detector just downstream of the source, and (3) a massive liquid argon time-projection chamber deployed as a far detector deep underground at the Sanford Underground Research Facility. This facility, located at the site of the former Homestake Mine in Lead, South Dakota, is approximately 1,300 km from the neutrino source at Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino charge-parity symmetry violation and mass ordering effects. This ambitious yet cost-effective design incorporates scalability and flexibility and can accommodate a variety of upgrades and contributions. With its exceptional combination of experimental configuration, technical capabilities, and potential for transformative discoveries, LBNE promises to be a vital facility for the field of particle physics worldwide, providing physicists from around the globe with opportunities to collaborate in a twenty to thirty year program of exciting science. In this document we provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess.Comment: Major update of previous version. This is the reference document for LBNE science program and current status. Chapters 1, 3, and 9 provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess. 288 pages, 116 figure

    Evaluation and comparison between methods of measurement of systolic blood pressure in healthy conscious cats

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    Após validação de dois diferentes métodos de mensuração de pressão arterial sistólica (PAS) não invasivos ou indiretos (oscilométrico e Doppler vascular) com o invasivo ou direto (cateterização arterial padrão ouro) em 12 gatos hígidos anestesiados de mesma faixa etária, os métodos não invasivos foram avaliados e comparados em 24 gatos hígidos e conscientes, divididos em quatro grupos de idade. Em cada animal, procedeu-se à mensuração da pressão pelos métodos Doppler e oscilométrico. O método oscilométrico foi o primeiro a ser realizado, e, logo em seguida, o método Doppler. Os valores considerados foram obtidos das médias de sete medidas consecutivas para cada método, com intervalo de 30 segundos entre elas. A primeira medida e as medidas discrepantes (variação ˃ 20% PAS), obtidas com sinais óbvios de estresse e/ou com movimentação do animal, foram descartadas. Os métodos de mensuração oscilométrico e Doppler, embora tenham apresentado médias estatisticamente diferentes em todos os grupos, quando comparados em cada grupo, apresentaram uma correlação significativa, alta e positiva. Ou seja, sempre que for obtido um valor elevado por um método, o mesmo fato ocorrerá com o outro método e vice-versa. Clinicamente, a diferença observada não é relevante, uma vez que a diferença média dos valores obtida pelos dois métodos, em cada grupo, foi menor que 1,1%.After two different validation systolic blood pressure measurement methods (PAS), not invasive or indirect (oscillometric and doppler vascular) with invasive or direct (arterial catheterization - Gold Standard) in 12 anesthetized healthy cats of the same age group, not invasive methods were evaluated and compared in 24 healthy conscious cats, divided into four age groups. In each animal, we proceeded to measure the pressure by Doppler and oscillometric methods. The oscillometric method was the first to be performed, and, shortly thereafter, the doppler method. The values considered were obtained from averages from seven consecutive measurements for each method with an interval of thirty seconds between them. The first measurement and disparate measurements (range ˃ 20% PAS) obtained with obvious signs of stress and / or animal movement were discarded. Methods of oscillometric and doppler measurement, although statistically different averages were shown in all groups when compared, each group showed a significant high positive correlation, meaning that when a high value is obtained by a method, the same occurs with the other method, and vice versa. Clinically, the observed difference is not relevant since the mean difference values obtained by the two methods, in each group was lower than 1.1%
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