90 research outputs found

    Impact of asthma education and/or specialized asthma care on subsequent morbidity in asthmatic children

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    Introduction: Des essais cliniques randomisĂ©s ont dĂ©montrĂ© que l'Ă©ducation sur l'asthme, sans ou avec un suivi mĂ©dical, rĂ©duit le risque de visites Ă  l’urgence subsĂ©quentes. Toutefois, l'Ă©ducation sur l'asthme et le suivi mĂ©dical spĂ©cialisĂ© sont souvent offerts dans des contextes diffĂ©rents, ce qui rend difficile l’implĂ©mentation en pratique clinique. Objectifs: Chez les enfants rĂ©fĂ©rĂ©s au Centre d’enseignement sur l’asthme (CEA) suite Ă  une visite Ă  l’urgence pour asthme, l’objectif principal est d’évaluer l’impact rĂ©el individuel et combinĂ© d’une visite au CEA et d’un suivi mĂ©dical spĂ©cialisĂ© (SMS) sur une visite Ă  l’urgence subsĂ©quente pour l’asthme au cours de l’annĂ©e suivante. MĂ©thodes: Étude de cohorte rĂ©trospective d’enfants rĂ©fĂ©rĂ©s au CEA dans l’annĂ©e suivant une visite Ă  l’urgence pour l’asthme. Le dĂ©lai jusqu’à la visite subsĂ©quente Ă  l’urgence pour asthme a Ă©tĂ© analysĂ© par un modĂšle Ă  risques proportionnels de Cox avec les variables d’exposition (CEA et SMS) variant dans le temps. RĂ©sultats: Comparativement aux enfants qui n’ont reçu aucune exposition, ceux qui ont effectuĂ© une visite au CEA seulement [Hazard Ratio (HR) =0.68, IC 95% 0.53-0.86] ou avec un SMS (HR=0.43, IC 95% 0.34-0.53) ont eu un risque instantanĂ© moins Ă©levĂ© d’une visite Ă  l’urgence subsĂ©quente. Une visite au SMS seule n’a pas d’effet statistiquement significatif. Conclusion: Dans une cohorte d’enfants rĂ©fĂ©rĂ©s au CEA suite Ă  une visite Ă  l’urgence pour l’asthme, le fait de recevoir l’éducation sur l’asthme avec ou sans suivi spĂ©cialisĂ© est associĂ© Ă  une protection contre une visite subsĂ©quente Ă  l’urgence.Background: Randomized controlled trials have shown that asthma education alone or in combination with medical review reduces the risk of subsequent emergency department (ED) visits. Nevertheless, asthma education and specialized care often provided in different settings, which increases the implementation burden in clinical practice. Objectives: In children referred to the Asthma Education Centre (AEC) following an ED visit for asthma, the primary objective was to evaluate the real-life individual and combined impact of an AEC visit and specialized asthma care (SAC) visit on a subsequent ED visit for asthma over the following year. Methods: Retrospective cohort study of children referred to the AEC in the year following an ED visit for asthma. The time to subsequent ED visit for asthma was analyzed by a Cox proportional hazards model with time-varying exposures (AEC and SAC). Results: Compared to the children who did not receive any of the exposures, those who had exposure to AEC alone [Hazard Ratio (HR) =0.68, CI 95% 0.53-0.86] or with SAC (HR=0.43, CI 95% 0.34-0.53) had a decreased risk of an earlier subsequent ED visit. Exposure to SAC alone did not have a statistically significant effect on a subsequent asthma visit for asthma Conclusion: In a cohort of children referred to the AEC following an ED visit for asthma, receiving asthma education with or without specialized care was associated with protection against a subsequent ED visit for asthma

    Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

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    A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

    Measurement of B-c(2S)(+) and B-c*(2S)(+) cross section ratios in proton-proton collisions at root s=13 TeV

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    Measurement of the W gamma Production Cross Section in Proton-Proton Collisions at root s=13 TeV and Constraints on Effective Field Theory Coefficients

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    A fiducial cross section for W gamma production in proton-proton collisions is measured at a center-of-mass energy of 13 TeV in 137 fb(-1) of data collected using the CMS detector at the LHC. The W -> e nu and mu nu decay modes are used in a maximum-likelihood fit to the lepton-photon invariant mass distribution to extract the combined cross section. The measured cross section is compared with theoretical expectations at next-to-leading order in quantum chromodynamics. In addition, 95% confidence level intervals are reported for anomalous triple-gauge couplings within the framework of effective field theory.Peer reviewe

    Search for dark photons in Higgs boson production via vector boson fusion in proton-proton collisions at √s = 13 TeV

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    A search is presented for a Higgs boson that is produced via vector boson fusion and that decays to an undetected particle and an isolated photon. The search is performed by the CMS collaboration at the LHC, using a data set corresponding to an integrated luminosity of 130 fb−1, recorded at a center-of-mass energy of 13 TeV in 2016–2018. No significant excess of events above the expectation from the standard model background is found. The results are interpreted in the context of a theoretical model in which the undetected particle is a massless dark photon. An upper limit is set on the product of the cross section for production via vector boson fusion and the branching fraction for such a Higgs boson decay, as a function of the Higgs boson mass. For a Higgs boson mass of 125 GeV, assuming the standard model production rates, the observed (expected) 95% confidence level upper limit on the branching fraction is 3.5 (2.8)%. This is the first search for such decays in the vector boson fusion channel. Combination with a previous search for Higgs bosons produced in association with a Z boson results in an observed (expected) upper limit on the branching fraction of 2.9 (2.1)% at 95% confidence level

    Performance of the CMS muon trigger system in proton-proton collisions at √s = 13 TeV

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    The muon trigger system of the CMS experiment uses a combination of hardware and software to identify events containing a muon. During Run 2 (covering 2015-2018) the LHC achieved instantaneous luminosities as high as 2 × 10 cm s while delivering proton-proton collisions at √s = 13 TeV. The challenge for the trigger system of the CMS experiment is to reduce the registered event rate from about 40 MHz to about 1 kHz. Significant improvements important for the success of the CMS physics program have been made to the muon trigger system via improved muon reconstruction and identification algorithms since the end of Run 1 and throughout the Run 2 data-taking period. The new algorithms maintain the acceptance of the muon triggers at the same or even lower rate throughout the data-taking period despite the increasing number of additional proton-proton interactions in each LHC bunch crossing. In this paper, the algorithms used in 2015 and 2016 and their improvements throughout 2017 and 2018 are described. Measurements of the CMS muon trigger performance for this data-taking period are presented, including efficiencies, transverse momentum resolution, trigger rates, and the purity of the selected muon sample. This paper focuses on the single- and double-muon triggers with the lowest sustainable transverse momentum thresholds used by CMS. The efficiency is measured in a transverse momentum range from 8 to several hundred GeV

    Search for long-lived particles decaying to jets with displaced vertices in proton-proton collisions at root s=13 Te V

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    A search is presented for long-lived particles produced in pairs in proton-proton collisions at the LHC operating at a center-of-mass energy of 13 TeV. The data were collected with the CMS detector during the period from 2015 through 2018, and correspond to a total integrated luminosity of 140 fb(-1). This search targets pairs of long-lived particles with mean proper decay lengths between 0.1 and 100 mm, each of which decays into at least two quarks that hadronize to jets, resulting in a final state with two displaced vertices. No significant excess of events with two displaced vertices is observed. In the context of R-parity violating supersymmetry models, the pair production of long-lived neutralinos, gluinos, and top squarks is excluded at 95% confidence level for cross sections larger than 0.08 fb, masses between 800 and 3000 GeV, and mean proper decay lengths between 1 and 25 mm.Peer reviewe

    Search for top squark production in fully hadronic final states in proton-proton collisions at root s=13 TeV

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    A search for production of the supersymmetric partners of the top quark, top squarks, is presented. The search is based on proton-proton collision events containing multiple jets, no leptons, and large transverse momentum imbalance. The data were collected with the CMS detector at the CERN LHC at a center-of-mass energy of 13 TeV, and correspond to an integrated luminosity of 137 fb(-1). The targeted signal production scenarios are direct and gluino-mediated top squark production, including scenarios in which the top squark and neutralino masses are nearly degenerate. The search utilizes novel algorithms based on deep neural networks that identify hadronically decaying top quarks and W bosons, which are expected in many of the targeted signal models. No statistically significant excess of events is observed relative to the expectation from the standard model, and limits on the top squark production cross section are obtained in the context of simplified supersymmetric models for various production and decay modes. Exclusion limits as high as 1310 GeVare established at the 95% confidence level on the mass of the top squark for direct top squark production models, and as high as 2260 GeV on the mass of the gluino for gluino-mediated top squark production models. These results represent a significant improvement over the results of previous searches for supersymmetry by CMS in the same final state.Peer reviewe

    Search for a heavy resonance decaying to a top quark and a w boson at √s = 13 tev in the fully hadronic final state

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    A search for a heavy resonance decaying to a top quark and a W boson in the fully hadronic final state is presented. The analysis is performed using data from proton-proton collisions at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 137 fb−1 recorded by the CMS experiment at the LHC. The search is focused on heavy resonances, where the decay products of each top quark or W boson are expected to be reconstructed as a single, large-radius jet with a distinct substructure. The production of an excited bottom quark, b*, is used as a benchmark when setting limits on the cross section for a heavy resonance decaying to a top quark and a W boson. The hypotheses of b* quarks with left-handed, right-handed, and vector-like chiralities are excluded at 95% confidence level for masses below 2.6, 2.8, and 3.1 TeV, respectively. These are the most stringent limits on the b* quark mass to date, extending the previous best limits by almost a factor of two

    Measurement of the Higgs boson production rate in association with top quarks in final states with electrons, muons, and hadronically decaying tau leptons at s√=13TeV

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    The rate for Higgs (H) bosons production in association with either one (tH) or two (ttÂŻH) top quarks is measured in final states containing multiple electrons, muons, or tau leptons decaying to hadrons and a neutrino, using proton–proton collisions recorded at a center-of-mass energy of 13TeV by the CMS experiment. The analyzed data correspond to an integrated luminosity of 137fb−1. The analysis is aimed at events that contain H→WW, H→ττ, or H→ZZ decays and each of the top quark(s) decays either to lepton+jets or all-jet channels. Sensitivity to signal is maximized by including ten signatures in the analysis, depending on the lepton multiplicity. The separation among tH, ttÂŻH, and the backgrounds is enhanced through machine-learning techniques and matrix-element methods. The measured production rates for the ttÂŻH and tH signals correspond to 0.92±0.19(stat)+0.17−0.13(syst) and 5.7±2.7(stat)±3.0(syst) of their respective standard model (SM) expectations. The corresponding observed (expected) significance amounts to 4.7 (5.2) standard deviations for ttÂŻH, and to 1.4 (0.3) for tH production. Assuming that the Higgs boson coupling to the tau lepton is equal in strength to its expectation in the SM, the coupling yt of the Higgs boson to the top quark divided by its SM expectation, Îșt=yt/ySMt, is constrained to be within −0.9<Îșt<−0.7 or 0.7<Îșt<1.1, at 95% confidence level. This result is the most sensitive measurement of the ttÂŻH production rate to date.SCOAP
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