1,712 research outputs found

    Recurrent apparent life-threatening event as the first manifestation of congenital myasthenia

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    OBJECTIVE: To alert pediatricians about the importance of a careful investigation on recurrent apparent life-threatening events. Reports of the association of these events with congenital myasthenic syndromes were not found. CASE DESCRIPTION: A seven-month-old infant with recurrent apparent life-threatening events was admitted for investigation. During hospital stay, she presented cyanosis and respiratory failure, requiring mechanical ventilation for three days. After clinical improvement, hypotheses of gastroesophageal reflux and pulmonary aspiration were ruled out. The presence of eyelid ptosis, general hypotonia and weak crying led to the suspicion of congenital myasthenia, which was confirmed. Treatment with oral piridostigmine led to neurological and nutritional normalization, without any other apparent life-threatening event during the next three years. COMMENTS: The careful etiological investigation of apparent life-threatening events may lead to rare diagnosis that requires specific treatments, such as congenital myasthenia.OBJETIVO: Alertar os pediatras sobre a necessidade de investigar criteriosamente a etiologia de eventos com aparente risco de morte recorrente. Não foram encontrados relatos associando tais eventos à miastenia congênita. DESCRIÇÃO DO CASO: Lactente de sete meses apresentando história de eventos com aparente risco de morte recorrente foi internado para investigação. Durante a internação, apresentou cianose e dispneia progressiva, com necessidade de ventilação mecânica por três dias. Após a melhora clínica, e tendo sido descartadas as hipóteses de doença do refluxo gastroesofágico e aspiração pulmonar como desencadeantes, notou-se ptose palpebral bilateral, hipotonia apendicular e choro fraco, que conduziram à suspeita clínica de miastenia congênita. Após confirmação do diagnóstico, foi mantido tratamento ambulatorial com piridostigmina, com recuperação nutricional e neurológica, sem novos eventos com aparente risco de morte nos três anos seguintes. COMENTÁRIOS: A investigação minuciosa das causas de eventos com aparente risco de morte pode levar a diagnósticos menos frequentes que exigem tratamento específico, como a miastenia congênita.OBJETIVO: Alertar a los pediatras sobre la necesidad de investigar criteriosamente la etiología de eventos con aparente riesgo de muerte recurrente. No se encontraron relatos asociando tales eventos a la miastenia congénita. DESCRIPCIÓN DEL CASO: Lactante de siete meses presentando historia de eventos con aparente riesgo de muerte recurrente fue internado para investigación. Durante la internación, presentó cianosis y disnea progresiva, con necesidad de ventilación mecánica por tres días. Después de la mejora clínica, y habiendo sido rechazadas las hipótesis de enfermedad del reflujo gastroesofágico y aspiración pulmonar como desencadenantes, se notó ptosis palpebral bilateral, hipotonía apendicular y lloro débil, que condujeron a la sospecha clínica de miastenia congénita. Después de la confirmación del diagnóstico, se mantuvo el tratamiento ambulatorial con piridostigmina, con recuperación nutricional y neurológica, sin nuevos eventos con aparente riesgo de muerte en los tres años siguientes. COMENTARIOS: La investigación minuciosa de las causas de eventos con aparente riesgo de muerte puede llevar a diagnósticos menos frecuentes que exigen tratamiento específico, como la miastenia congénita.12112

    Measurements of the differential cross sections of the production of Z + jets and γ + jets and of Z boson emission collinear with a jet in pp collisions at s \sqrt{s} = 13 TeV

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    Measurements of the differential cross sections of Z + jets and γ + jets production, and their ratio, are presented as a function of the boson transverse momentum. Measurements are also presented of the angular distribution between the Z boson and the closest jet. The analysis is based on pp collisions at a center-of-mass energy of 13 TeV corresponding to an integrated luminosity of 35.9 fb−1 recorded by the CMS experiment at the LHC. The results, corrected for detector effects, are compared with various theoretical predictions. In general, the predictions at higher orders in perturbation theory show better agreement with the measurements. This work provides the first measurement of the ratio of the differential cross sections of Z + jets and γ + jets production at 13 TeV, as well as the first direct measurement of Z bosons emitted collinearly with a jet

    Search for decays of the 125 GeV Higgs boson into a Z boson and a ρ or ϕ meson

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    Decays of the 125 GeV Higgs boson into a Z boson and a ρ^0(770) or ϕ(1020) meson are searched for using proton-proton collision data collected by the CMS experiment at the LHC at √s = 13 TeV. The analysed data set corresponds to an integrated luminosity of 137 fb⁻¹. Events are selected in which the Z boson decays into a pair of electrons or a pair of muons, and the ρ and ϕ mesons decay into pairs of pions and kaons, respectively. No significant excess above the background model is observed. As different polarization states are possible for the decay products of the Z boson and ρ or ϕ mesons, affecting the signal acceptance, scenarios in which the decays are longitudinally or transversely polarized are considered. Upper limits at the 95% confidence level on the Higgs boson branching fractions into Zρ and Zϕ are determined to be 1.04–1.31% and 0.31–0.40%, respectively, where the ranges reflect the considered polarization scenarios; these values are 740–940 and 730–950 times larger than the respective standard model expectations. These results constitute the first experimental limits on the two decay channels

    Constraints on the Initial State of Pb-Pb Collisions via Measurements of Z-Boson Yields and Azimuthal Anisotropy at root s(NN)=5.02 TeV

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    The CMS experiment at the LHC has measured the differential cross sections of Z bosons decaying to pairs of leptons, as functions of transverse momentum and rapidity, in lead-lead collisions at a nucleon-nucleon center-of-mass energy of 5.02 TeV. The measured Z boson elliptic azimuthal anisotropy coefficient is compatible with zero, showing that Z bosons do not experience significant final-state interactions in the medium produced in the collision. Yields of Z bosons are compared to Glauber model predictions and are found to deviate from these expectations in peripheral collisions, indicating the presence of initial collision geometry and centrality selection effects. The precision of the measurement allows, for the first time, for a data-driven determination of the nucleon-nucleon integrated luminosity as a function of lead-lead centrality, thereby eliminating the need for its estimation based on a Glauber model.Peer reviewe

    Search for the lepton flavor violating decay τ → 3μ in proton-proton collisions at s \sqrt{\mathrm{s}} = 13 TeV

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    Results are reported from a search for the lepton flavor violating decay τ → 3μ in proton-proton collisions at s \sqrt{\mathrm{s}} = 13 TeV. The data sample corresponds to an integrated luminosity of 33.2 fb1^{-1} recorded by the CMS experiment at the LHC in 2016. The search exploits τ leptons produced in both W boson and heavy-flavor hadron decays. No significant excess above the expected background is observed. An upper limit on the branching fraction B(τ → 3μ) of 8.0 x 108^{-8} at 90% confidence level is obtained, with an expected upper limit of 6.9 x 108^{-8}

    Measurements of production cross sections of WZ and same-sign WW boson pairs in association with two jets in proton-proton collisions at √s = 13 TeV

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    The first measurements of production cross sections of polarized same-sign W±^{±} W±^{±} boson pairs in proton-proton collisions are reported. The measurements are based on a data sample collected with the CMS detector at the LHC at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 137fb1^{-1}. Events are selected by requiring exactly two same-sign leptons, electrons or muons, moderate missing transverse momentum, and two jets with a large rapidity separation and a large dijet mass to enhance the contribution of same-sign W±^{±} W±^{±} scattering events. An observed (expected) 95% confidence level upper limit of 1.17 (0.88) fbis set on the production cross section for longitudinally polarized same-sign W±^{±} W±^{±} boson pairs. The electroweak production of same-sign W±^{±} W±^{±} boson pairs with at least one of the W bosons longitudinally polarized is measured with an observed (expected) significance of 2.3 (3.1) standard deviations

    Search for supersymmetry in proton-proton collisions at s \sqrt{s} = 13 TeV in events with high-momentum Z bosons and missing transverse momentum

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    Inclusive search for highly boosted Higgs bosons decaying to bottom quark-antiquark pairs in proton-proton collisions at <mml:msqrt>s</mml:msqrt>=13 TeV

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