735 research outputs found

    A reverse engineering approach to the suppression of citation biases reveals universal properties of citation distributions

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    The large amount of information contained in bibliographic databases has recently boosted the use of citations, and other indicators based on citation numbers, as tools for the quantitative assessment of scientific research. Citations counts are often interpreted as proxies for the scientific influence of papers, journals, scholars, and institutions. However, a rigorous and scientifically grounded methodology for a correct use of citation counts is still missing. In particular, cross-disciplinary comparisons in terms of raw citation counts systematically favors scientific disciplines with higher citation and publication rates. Here we perform an exhaustive study of the citation patterns of millions of papers, and derive a simple transformation of citation counts able to suppress the disproportionate citation counts among scientific domains. We find that the transformation is well described by a power-law function, and that the parameter values of the transformation are typical features of each scientific discipline. Universal properties of citation patterns descend therefore from the fact that citation distributions for papers in a specific field are all part of the same family of univariate distributions.Comment: 9 pages, 6 figures. Supporting information files available at http://filrad.homelinux.or

    Predictors of Medication Adherence and Blood Pressure Control among Saudi Hypertensive Patients Attending Primary Care Clinics: A Cross-Sectional Study

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    Purpose To assess the level of medication adherence and to investigate predictors of medication adherence and blood pressure control among hypertensive patients attending primary healthcare clinics in Makkah, Saudi Arabia. Patients and methods Hypertensive patients meeting the eligibility criteria were recruited from eight primary care clinics between January and May 2016 for this study. The patients completed Arabic version of Morisky Medication Adherence Scale (MMAS-8), an eight-item validated, self-reported measure to assess medication adherence. A structured data collection form was used to record patients’ sociodemographic, medical and medication data. Results Two hundred and four patients, of which 71.6% were females, participated in the study. Patients’ mean age was 59.1 (SD 12.2). The mean number of medication used by patients was 4.4 (SD 1.89). More than half (110; 54%) of the patients were non-adherent to their medications (MMAS score 65 years (OR 2.0 [95% CI: 1.0–4.2; P = 0.04]), and being diabetic (OR 0.25 [95% CI: 0.1–0.6; P = 0.04]) were found to be independent predictors of medication adherence. Conclusion Medication adherence is alarmingly low among hypertensive patients attending primary care clinics in Saudi Arabia which may partly explain observed poor blood pressure control. There is a clear need to educate patients about the importance of medication adherence and its impact on improving clinical outcomes. Future research should identify barriers to medication adherence among Saudi hypertensive patients

    Observation of associated near-side and away-side long-range correlations in √sNN=5.02  TeV proton-lead collisions with the ATLAS detector

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    Two-particle correlations in relative azimuthal angle (Δϕ) and pseudorapidity (Δη) are measured in √sNN=5.02  TeV p+Pb collisions using the ATLAS detector at the LHC. The measurements are performed using approximately 1  μb-1 of data as a function of transverse momentum (pT) and the transverse energy (ΣETPb) summed over 3.1<η<4.9 in the direction of the Pb beam. The correlation function, constructed from charged particles, exhibits a long-range (2<|Δη|<5) “near-side” (Δϕ∼0) correlation that grows rapidly with increasing ΣETPb. A long-range “away-side” (Δϕ∼π) correlation, obtained by subtracting the expected contributions from recoiling dijets and other sources estimated using events with small ΣETPb, is found to match the near-side correlation in magnitude, shape (in Δη and Δϕ) and ΣETPb dependence. The resultant Δϕ correlation is approximately symmetric about π/2, and is consistent with a dominant cos⁡2Δϕ modulation for all ΣETPb ranges and particle pT

    Search for direct pair production of the top squark in all-hadronic final states in proton-proton collisions at s√=8 TeV with the ATLAS detector

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    The results of a search for direct pair production of the scalar partner to the top quark using an integrated luminosity of 20.1fb−1 of proton–proton collision data at √s = 8 TeV recorded with the ATLAS detector at the LHC are reported. The top squark is assumed to decay via t˜→tχ˜01 or t˜→ bχ˜±1 →bW(∗)χ˜01 , where χ˜01 (χ˜±1 ) denotes the lightest neutralino (chargino) in supersymmetric models. The search targets a fully-hadronic final state in events with four or more jets and large missing transverse momentum. No significant excess over the Standard Model background prediction is observed, and exclusion limits are reported in terms of the top squark and neutralino masses and as a function of the branching fraction of t˜ → tχ˜01 . For a branching fraction of 100%, top squark masses in the range 270–645 GeV are excluded for χ˜01 masses below 30 GeV. For a branching fraction of 50% to either t˜ → tχ˜01 or t˜ → bχ˜±1 , and assuming the χ˜±1 mass to be twice the χ˜01 mass, top squark masses in the range 250–550 GeV are excluded for χ˜01 masses below 60 GeV

    Bayesian analysis using MCMC methods of record values based on a new generalised Rayleigh distribution

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    In this paper, we extend the Rayleigh distribution to create a generalised Rayleigh distribution which is more flexible than the standard. The general properties of the new distribution are derived and investigated, with properties of more standard distributions, such as the exponential, standard Rayleigh and the Weibull, appearing as special cases. Further, we consider maximum likelihood estimation and Bayesian inference under the assumptions of gamma prior distributions on model parameters. Point estimates and confidence intervals based on maximum likelihood estimation are computed. The main challenge, however, is that the Bayesian estimators cannot easily be found and hence, Markov chain Monte Carlo (MCMC) techniques are proposed to generate samples from the posterior distributions leading to approximate posterior inference. The approximate Bayes estimators are compared with the maximum likelihood estimators using simulated data showing dramatic superiority of the Bayesian approach

    Effect of supplementing flaxseed oil on growth and carcass traits of Friesian bulls

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    ΔΕΝ ΔΙΑΤΙΘΕΤΑΙ ΠΕΡΙΛΗΨΗThis study aimed to evaluate effects of supplementing flaxseed oil (FSO) on growth and carcass traits, as well as meat chemical composition, quality, and fatty acids (FA) profile in Friesian bulls. The bulls (n = 30) were randomly divided into 3 groups (G1-G3, n = 10/group). In G1 (control), animals fed basal diet, while in G2 and G3, they were supplemented with 2% and 4% FSO, respectively, for ~ 7 months. The obtained results revealed that bulls fed diet supplemented with 2% (G2) and 4% (G3) FSO had significantly higher TDN intake (P ˂ 0.01) and average daily gain (P ˂ 0.05) than G1. Additionally, G3 showed significantly higher hot carcass weight (P&lt;0.001), dressing % (P&lt;0.05), fat weight (P&lt;0.05), boneless meat weight (P&lt;0.001), 9-11th ribs cut weights (P&lt;0.05), DM (P&lt;0.01), CP (P&lt;0.05), and CF (P&lt;0.05) in eye muscle, and general cooked meat quality (P&lt;0.05) than G1. However, meat of G3 had significantly (P&lt;0.05) lower water-holding capacity than G1. Meat contents of C20:0 and C22:0 SFAs were significantly higher in G3 (P&lt;0.05) than G1, while C14:0, C15:0, and C17:0 were significantly (P&lt;0.05) lower in G3 and G2 than G1. C16:1 trans-9 MUFA was significantly higher in G3 (P&lt;0.01) and G2 (P&lt;0.05) than G1, while C18:1 cis-9 +trans-13-14 and C20:1 cis-11 were significantly lower in G3 (P&lt;0.001) and G2 (P&lt;0.05) than G1. Among the 2 treated groups, only G3 had significantly higher C17:1 cis-9 (P&lt;0.05), C18:1 cis-11+trans15 (P&lt;0.01), and C18:1 cis-15+trans-16 (P&lt;0.01) and significantly lower C16:1 cis-7 (P&lt;0.05) and C18:1 trans-12 (P&lt;0.01) than G1. Meat contents of C18:3 n-3 (ALA), C22:5 n-3 (EPA) and C22:6 n-3 (DHA) was significantly higher in G3 (P&lt;0.0001) and G2 (P&lt;0.05) than G1. The total n-3 FAs content in meat was significantly (P&lt;0.0001) higher in G3 and G2 than G1, while only G3 showed significantly higher total PUFA (P&lt;0.05) than G1. The n-6:n-3 ratio was significantly (P&lt;0.0001) lower in G3 and G2 than G1. With these results, we could conclude that flaxseed oil supplementation in bull diets could improve growth performance, and carcass quality and increase omega-3 FA in animal meat

    Search for R-parity-violating supersymmetry in events with four or more leptons in sqrt(s) =7 TeV pp collisions with the ATLAS detector

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    A search for new phenomena in final states with four or more leptons (electrons or muons) is presented. The analysis is based on 4.7 fb−1 of s=7  TeV \sqrt{s}=7\;\mathrm{TeV} proton-proton collisions delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in two signal regions: one that requires moderate values of missing transverse momentum and another that requires large effective mass. The results are interpreted in a simplified model of R-parity-violating supersymmetry in which a 95% CL exclusion region is set for charged wino masses up to 540 GeV. In an R-parity-violating MSUGRA/CMSSM model, values of m 1/2 up to 820 GeV are excluded for 10 < tan β < 40

    Measurement of the cross-section of high transverse momentum vector bosons reconstructed as single jets and studies of jet substructure in pp collisions at √s = 7 TeV with the ATLAS detector

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    This paper presents a measurement of the cross-section for high transverse momentum W and Z bosons produced in pp collisions and decaying to all-hadronic final states. The data used in the analysis were recorded by the ATLAS detector at the CERN Large Hadron Collider at a centre-of-mass energy of √s = 7 TeV;{\rm Te}{\rm V}andcorrespondtoanintegratedluminosityof and correspond to an integrated luminosity of 4.6\;{\rm f}{{{\rm b}}^{-1}}.ThemeasurementisperformedbyreconstructingtheboostedWorZbosonsinsinglejets.ThereconstructedjetmassisusedtoidentifytheWandZbosons,andajetsubstructuremethodbasedonenergyclusterinformationinthejetcentreofmassframeisusedtosuppressthelargemultijetbackground.ThecrosssectionforeventswithahadronicallydecayingWorZboson,withtransversemomentum. The measurement is performed by reconstructing the boosted W or Z bosons in single jets. The reconstructed jet mass is used to identify the W and Z bosons, and a jet substructure method based on energy cluster information in the jet centre-of-mass frame is used to suppress the large multi-jet background. The cross-section for events with a hadronically decaying W or Z boson, with transverse momentum {{p}_{{\rm T}}}\gt 320\;{\rm Ge}{\rm V}andpseudorapidity and pseudorapidity |\eta |\lt 1.9,ismeasuredtobe, is measured to be {{\sigma }_{W+Z}}=8.5\pm 1.7$ pb and is compared to next-to-leading-order calculations. The selected events are further used to study jet grooming techniques
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