1,927 research outputs found

    Holographic Dark Energy with Curvature

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    In this paper we consider an holographic model of dark energy, where the length scale is the Hubble radius, in a non flat geometry. The model contains the possibility to alleviate the cosmic coincidence problem, and also incorporate a mechanism to obtain the transition from decelerated to an accelerated expansion regime. We derive an analytic form for the Hubble parameter in a non flat universe, and using it, we perform a Bayesian analysis of this model using SNIa, BAO and CMB data. We find from this analysis that the data favored a small value for Ωk\Omega_k, however high enough to still produce cosmological consequences.Comment: 6 pages, 2 figure

    Eternity and the cosmological constant

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    The purpose of this paper is to analyze the stability of interacting matter in the presence of a cosmological constant. Using an approach based on the heat equation, no imaginary part is found for the effective potential in the presence of a fixed background, which is the n-dimensional sphere or else an analytical continuation thereof, which is explored in some detail.Comment: 45 pages, 6 figure

    Complex regional pain syndrome 1 – the Swiss cohort study

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    BACKGROUND: Little is known about the course of Complex Regional Pain Syndrome 1 and potential factors influencing the course of this disorder over time. The goal of this study is a) to set up a database with patients suffering from suspected CRPS 1 in an initial stadium, b) to perform investigations on epidemiology, diagnosis, prognosis, and socioeconomics within the database and c) to develop a prognostic risk assessment tool for patients with CRPS 1 taking into account symptomatology and specific therapies. METHODS/DESIGN: Prospective cohort study. Patients suffering from a painful swelling of the hand or foot which appeared within 8 weeks after a trauma or a surgery and which cannot be explained by conditions that would otherwise account for the degree of pain and dysfunction will be included. In accordance with the recommendations of International Classification of Functioning, Disability and Health (ICF model), standardised and validated questionnaires will be used. Patients will be monitored over a period of 2 years at 6 scheduled visits (0 and 6 weeks, 3, 6, 12, and 24 months). Each visit involves a physical examination, registration of therapeutic interventions, and completion of the various study questionnaires. Outcomes involve changes in health status, quality of life and costs/utility. DISCUSSION: This paper describes the rationale and design of patients with CRPS 1. Ideally, potential risk factors may be identified at an early stage in order to initiate an early and adequate treatment in patients with increased risk for delayed recovery

    Measurement of Branching Fractions and Rate Asymmetries in the Rare Decays B -> K(*) l+ l-

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    In a sample of 471 million BB events collected with the BABAR detector at the PEP-II e+e- collider we study the rare decays B -> K(*) l+ l-, where l+ l- is either e+e- or mu+mu-. We report results on partial branching fractions and isospin asymmetries in seven bins of di-lepton mass-squared. We further present CP and lepton-flavor asymmetries for di-lepton masses below and above the J/psi resonance. We find no evidence for CP or lepton-flavor violation. The partial branching fractions and isospin asymmetries are consistent with the Standard Model predictions and with results from other experiments.Comment: 16 pages, 14 figures, accepted by Phys. Rev.

    Measurement of CP Asymmetries and Branching Fractions in Charmless Two-Body B-Meson Decays to Pions and Kaons

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    We present improved measurements of CP-violation parameters in the decays B0π+πB^0 \to \pi^+ \pi^-, B0K+πB^0 \to K^+ \pi^-, and B0π0π0B^0 \to \pi^0 \pi^0, and of the branching fractions for B0π0π0B^0 \to \pi^0 \pi^0 and B0K0π0B^0 \to K^0 \pi^0. The results are obtained with the full data set collected at the Υ(4S)\Upsilon(4S) resonance by the BABAR experiment at the PEP-II asymmetric-energy BB factory at the SLAC National Accelerator Laboratory, corresponding to 467±5467 \pm 5 million BBˉB\bar B pairs. We find the CP-violation parameter values and branching fractions Sπ+π=0.68±0.10±0.03,Cπ+π=0.25±0.08±0.02,AKπ+=0.107±0.0160.004+0.006,Cπ0π0=0.43±0.26±0.05,Br(B0π0π0)=(1.83±0.21±0.13)×106,Br(B0K0π0)=(10.1±0.6±0.4)×106, S_{\pi^+\pi^-} = -0.68 \pm 0.10 \pm 0.03, C_{\pi^+\pi^-} = -0.25 \pm 0.08 \pm 0.02, A_{K^-\pi^+} = -0.107 \pm 0.016 ^{+0.006}_{-0.004}, C_{\pi^0\pi^0} = -0.43 \pm 0.26 \pm 0.05, Br(B^0 \to \pi^0 \pi^0) = (1.83 \pm 0.21 \pm 0.13) \times 10^{-6}, Br(B^0 \to K^0 \pi^0) = (10.1 \pm 0.6 \pm 0.4) \times 10^{-6}, where in each case, the first uncertainties are statistical and the second are systematic. We observe CP violation with a significance of 6.7 standard deviations for B0π+πB^0 \to\pi^+\pi^- and 6.1 standard deviations for B0K+πB^0 \to K^+ \pi^-, including systematic uncertainties. Constraints on the Unitarity Triangle angle α\alpha are determined from the isospin relations among the BππB \to \pi\pi rates and asymmetries. Considering only the solution preferred by the Standard Model, we find α\alpha to be in the range [71,109][71^\circ,109^\circ] at the 68% confidence level.Comment: 18 pages, 11 postscript figures, submitted to Phys. Rev.

    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

    Prospects for Genomic Selection in Cassava Breeding

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    Article purchased; Published online: 28 Sept 2017Cassava (Manihot esculenta Crantz) is a clonally propagated staple food crop in the tropics. Genomic selection (GS) has been implemented at three breeding institutions in Africa to reduce cycle times. Initial studies provided promising estimates of predictive abilities. Here, we expand on previous analyses by assessing the accuracy of seven prediction models for seven traits in three prediction scenarios: cross-validation within populations, cross-population prediction and cross-generation prediction. We also evaluated the impact of increasing the training population (TP) size by phenotyping progenies selected either at random or with a genetic algorithm. Cross-validation results were mostly consistent across programs, with nonadditive models predicting of 10% better on average. Cross-population accuracy was generally low (mean = 0.18) but prediction of cassava mosaic disease increased up to 57% in one Nigerian population when data from another related population were combined. Accuracy across generations was poorer than within-generation accuracy, as expected, but accuracy for dry matter content and mosaic disease severity should be sufficient for rapid-cycling GS. Selection of a prediction model made some difference across generations, but increasing TP size was more important. With a genetic algorithm, selection of one-third of progeny could achieve an accuracy equivalent to phenotyping all progeny. We are in the early stages of GS for this crop but the results are promising for some traits. General guidelines that are emerging are that TPs need to continue to grow but phenotyping can be done on a cleverly selected subset of individuals, reducing the overall phenotyping burden

    German translation and external validation of the Radboud Skills Questionnaire in patients suffering from Complex Regional Pain Syndrome 1

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    BACKGROUND: Patients suffering from Complex Regional Pain Syndrome commonly complain of substantial limitations in their activities of daily living. The Radboud Skills Questionnaire measures alterations in the level of disability of patients with Complex Regional Pain Syndrome, but this instrument is currently not available in German. The goals of our study were to translate the Dutch Radboud Skills Questionnaire into German and to assess its external criterion validity with the German version of the Disabilities of the Arm, Shoulder and Hand Questionnaire. METHODS: We translated the Radboud Skills Questionnaire according to published guidelines. Demographic data and validity were assessed in 57 consecutive patients with Complex Regional Pain Syndrome 1 of the upper extremity. Information on age, duration of symptoms, type of Complex Regional Pain Syndrome 1 and type of initiating event was obtained. We assessed the external criterion validity by comparing the German Radboud Skills Questionnaire and the German Disabilities of the Arm, Shoulder and Hand Questionnaire and calculated the prediction intervals. RESULTS: Score values ranged from 55.4 +/- 22.0 for the Disabilities of the Arm, Shoulder and Hand Questionnaire score and 140.1 +/- 39.2 for the Radboud Skills Questionnaire. We found a high correlation between the Radboud Skills Questionnaire and the Disabilities of the Arm, Shoulder and Hand Questionnaire (R2 = 0.83). CONCLUSION: This validation of the Radboud Skills Questionnaire demonstrates that this German version is a simple and accurate instrument to assess and quantify disabilities of patients suffering from Complex Regional Pain Syndrome 1 of the upper extremity for clinical and research purposes
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