284 research outputs found

    Asociación de la nutrición enteral temprana con desenlaces clínicos en pacientes sometidos a cirugía cardiaca en una unidad de cuidados intensivos cardiovasculares

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    Introduction: Early enteral nutrition (EEN) has been associated with improved clinical outcomes in subpopulations of patients in the intensive care unit (ICU). However, little evidence is available in critically ill patients undergoing cardiac surgery. Objective: To analyze the association between EEN with important clinical outcomes. Methods: Retrospective cohort study in post-surgical adult patients admitted to the ICU between august 2021 and october 2022, who required invasive mechanical ventilation (IMV) for more than 48 hours. The association between EEN use and ICU mortality, days under IMV, and days of ICU stay were evaluated through logistic and linear regression tests. Results: 74 patients were considered in the final analysis. The median days of ICU stay was lower in the EEN group compared to the delayed enteral nutrition group [8 (IQR 6 - 14) vs. 18 (7 - 31), p = 0.005, respectively], the same was observed with days under IMV [4 (3 - 6) vs. 11 (5 - 24), p = 0.000, respectively]. EEN was associated with decreased in hospital mortality (OR 0.21; 95%CI 0.07, 0.67; p = 0.009) and ICU mortality (OR 0.21; 95%CI 0.5, 0.84; p = 0. 027), as well as with days in ICU (β -8.03; 95%CI -13.44, -2.62; p = 0.004) and days under IMV (β -11.86; 95%CI -17.97, -5.74; p = 0.000) in the adjusted model. Conclusions: In critically ill patients undergoing cardiac surgery, EEN may be related to a decrease in hospital and ICU mortality, as well as length of ICU stay and days under IMV.Introducción: La nutrición enteral temprana (EEN) se ha asociado con mejores desenlaces clínicos en subpoblaciones de pacientes que se encuentran en la unidad de cuidados intensivos (UCI). Sin embargo, existe poca evidencia disponible en pacientes críticos sometidos a cirugía cardiaca. Objetivo: analizar la asociación entre la EEN con desenlaces clínicos importantes. Métodos: Estudio de cohorte retrospectivo en pacientes adultos postquirúrgicos ingresados a la UCI entre agosto de 2021 y octubre de 2022 que requirieron ventilación mecánica invasiva (VMI) por más de 48 horas. Se evaluó la asociación entre el uso de EEN y mortalidad hospitalaria y en la UCI, días bajo VMI, y días de estancia en UCI a través de pruebas de regresión logística y lineal. Resultados: 74 pacientes fueron considerados en el análisis. La mediana de días de estancia en la UCI fue menor en el grupo con EEN comparado con el grupo nutrición enteral tardía [8 (IQR 6 - 14) vs. 18 (7 - 31), p = 0.005, respectivamente], esto mismo fue observado con los días bajo VMI [4 (3 - 6) vs. 11 (5 - 24), p = 0.000, respectivamente]. La EEN se asoció con una disminución de mortalidad hospitalaria (OR 0.21; IC95% 0.07, 0.67; p = 0.009) y en la UCI (OR 0.21; IC95% 0.5, 0.84; p = 0.027), así como con los días de estancia en la UCI (β -8.03; IC95% -13.44, -2.62; p = 0.004) y días bajo VMI (β -11.86; IC95% -17.97, -5.74; p = 0.000) en el modelo ajustado. Conclusiones: En pacientes críticos sometidos a cirugía cardiaca el inicio de EEN puede estar relacionado con una disminución en la mortalidad hospitalaria y en la UCI, así como con los días de estancia en la UCI y bajo VMI

    Measurement of the Splitting Function in &ITpp &ITand Pb-Pb Collisions at root&ITsNN&IT=5.02 TeV

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    Data from heavy ion collisions suggest that the evolution of a parton shower is modified by interactions with the color charges in the dense partonic medium created in these collisions, but it is not known where in the shower evolution the modifications occur. The momentum ratio of the two leading partons, resolved as subjets, provides information about the parton shower evolution. This substructure observable, known as the splitting function, reflects the process of a parton splitting into two other partons and has been measured for jets with transverse momentum between 140 and 500 GeV, in pp and PbPb collisions at a center-of-mass energy of 5.02 TeV per nucleon pair. In central PbPb collisions, the splitting function indicates a more unbalanced momentum ratio, compared to peripheral PbPb and pp collisions.. The measurements are compared to various predictions from event generators and analytical calculations.Peer reviewe

    An embedding technique to determine ττ backgrounds in proton-proton collision data

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    An embedding technique is presented to estimate standard model tau tau backgrounds from data with minimal simulation input. In the data, the muons are removed from reconstructed mu mu events and replaced with simulated tau leptons with the same kinematic properties. In this way, a set of hybrid events is obtained that does not rely on simulation except for the decay of the tau leptons. The challenges in describing the underlying event or the production of associated jets in the simulation are avoided. The technique described in this paper was developed for CMS. Its validation and the inherent uncertainties are also discussed. The demonstration of the performance of the technique is based on a sample of proton-proton collisions collected by CMS in 2017 at root s = 13 TeV corresponding to an integrated luminosity of 41.5 fb(-1).Peer reviewe

    Measurement of t(t)over-bar normalised multi-differential cross sections in pp collisions at root s=13 TeV, and simultaneous determination of the strong coupling strength, top quark pole mass, and parton distribution functions

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    Measurement of nuclear modification factors of gamma(1S)), gamma(2S), and gamma(3S) mesons in PbPb collisions at root s(NN)=5.02 TeV

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    The cross sections for ϒ(1S), ϒ(2S), and ϒ(3S) production in lead-lead (PbPb) and proton-proton (pp) collisions at √sNN = 5.02 TeV have been measured using the CMS detector at the LHC. The nuclear modification factors, RAA, derived from the PbPb-to-pp ratio of yields for each state, are studied as functions of meson rapidity and transverse momentum, as well as PbPb collision centrality. The yields of all three states are found to be significantly suppressed, and compatible with a sequential ordering of the suppression, RAA(ϒ(1S)) > RAA(ϒ(2S)) > RAA(ϒ(3S)). The suppression of ϒ(1S) is larger than that seen at √sNN = 2.76 TeV, although the two are compatible within uncertainties. The upper limit on the RAA of ϒ(3S) integrated over pT, rapidity and centrality is 0.096 at 95% confidence level, which is the strongest suppression observed for a quarkonium state in heavy ion collisions to date. © 2019 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP3.Peer reviewe

    Electroweak production of two jets in association with a Z boson in proton-proton collisions root s =13 TeV

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    A measurement of the electroweak (EW) production of two jets in association with a Z boson in proton-proton collisions at root s = 13 TeV is presented, based on data recorded in 2016 by the CMS experiment at the LHC corresponding to an integrated luminosity of 35.9 fb(-1). The measurement is performed in the lljj final state with l including electrons and muons, and the jets j corresponding to the quarks produced in the hard interaction. The measured cross section in a kinematic region defined by invariant masses m(ll) > 50 GeV, m(jj) > 120 GeV, and transverse momenta P-Tj > 25 GeV is sigma(EW) (lljj) = 534 +/- 20 (stat) fb (syst) fb, in agreement with leading-order standard model predictions. The final state is also used to perform a search for anomalous trilinear gauge couplings. No evidence is found and limits on anomalous trilinear gauge couplings associated with dimension-six operators are given in the framework of an effective field theory. The corresponding 95% confidence level intervals are -2.6 <cwww/Lambda(2) <2.6 TeV-2 and -8.4 <cw/Lambda(2) <10.1 TeV-2. The additional jet activity of events in a signal-enriched region is also studied, and the measurements are in agreement with predictions.Peer reviewe

    Measurement of the t(t)over-bar production cross section, the top quark mass, and the strong coupling constant using dilepton events in pp collisions at root s=13TeV

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    A measurement of the top quark-antiquark pair production cross section sigma(t (t) over bar) in proton-proton collisions at a centre-of-mass energy of 13 TeV is presented. The data correspond to an integrated luminosity of 35.9 fb(-1), recorded by the CMS experiment at the CERN LHC in 2016. Dilepton events (e(+/-) mu(-/+), mu(+) mu(-), e(+) e(-)) are selected and the cross section is measured from a likelihood fit. For a top quark mass parameter in the simulation of m(t)(MC) = 172.5 GeV the fit yields a measured cross section sigma(t (t) over bar) = 803 +/- 2 (stat) +/- 25 (syst) +/- 20 (lumi) pb, in agreement with the expectation from the standard model calculation at next-to-next-to-leading order. A simultaneous fit of the cross section and the top quark mass parameter in the POWHEG simulation is performed. The measured value of m(t)(MC) = 172.33 +/- 0.14 (stat)(-0.72)(+0.66) (syst) GeV is in good agreement with previous measurements. The resulting cross section is used, together with the theoretical prediction, to determine the top quark mass and to extract a value of the strong coupling constant with different sets of parton distribution functions.Peer reviewe

    Measurement of electroweak WZ boson production and search for new physics in WZ + two jets events in pp collisions at √s=13TeV

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    A measurement of WZ electroweak (EW) vector boson scattering is presented. The measurement is performed in the leptonic decay modes WZ→ℓνℓ′ℓ′, where ℓ,ℓ′=e,μ. The analysis is based on a data sample of proton-proton collisions at √s=13 TeV at the LHC collected with the CMS detector and corresponding to an integrated luminosity of 35.9 fb−1. The WZ plus two jet production cross section is measured in fiducial regions with enhanced contributions from EW production and found to be consistent with standard model predictions. The EW WZ production in association with two jets is measured with an observed (expected) significance of 2.2 (2.5) standard deviations. Constraints on charged Higgs boson production and on anomalous quartic gauge couplings in terms of dimension-eight effective field theory operators are also presented

    Studies of Beauty Suppression via Nonprompt D-0 Mesons in Pb-Pb Collisions at root s(NN)=5.02 TeV

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    The transverse momentum spectra of D-0 mesons from b hadron decays are measured at midrapidity (vertical bar y vertical bar D-0 yield is found to be suppressed in the measured p(T) range from 2 to 100 GeV/c as compared to pp collisions. The suppression is weaker than that of prompt D-0 mesons and charged hadrons for p(T) around 10 GeV/c. While theoretical calculations incorporating partonic energy loss in the quark-gluon plasma can successfully describe the measured B -> D-0 suppression at higher p(T), the data show an indication of larger suppression than the model predictions in the range of 2 <p(T) <5 GeV/c.Peer reviewe

    Bose-Einstein correlations of charged hadrons in proton-proton collisions at s\sqrt s = 13 TeV

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    Bose-Einstein correlations of charged hadrons are measured over a broad multiplicity range, from a few particles up to about 250 reconstructed charged hadrons in proton-proton collisions at s \sqrt{s} = 13 TeV. The results are based on data collected using the CMS detector at the LHC during runs with a special low-pileup configuration. Three analysis techniques with different degrees of dependence on simulations are used to remove the non-Bose-Einstein background from the correlation functions. All three methods give consistent results. The measured lengths of homogeneity are studied as functions of particle multiplicity as well as average pair transverse momentum and mass. The results are compared with data from both CMS and ATLAS at s \sqrt{s} = 7 TeV, as well as with theoretical predictions.[graphic not available: see fulltext]Bose-Einstein correlations of charged hadrons are measured over a broad multiplicity range, from a few particles up to about 250 reconstructed charged hadrons in proton-proton collisions at s=\sqrt{s} = 13 TeV. The results are based on data collected using the CMS detector at the LHC during runs with a special low-pileup configuration. Three analysis techniques with different degrees of dependence on simulations are used to remove the non-Bose-Einstein background from the correlation functions. All three methods give consistent results. The measured lengths of homogeneity are studied as functions of particle multiplicity as well as average pair transverse momentum and mass. The results are compared with data from both CMS and ATLAS at s=\sqrt{s} = 7 TeV, as well as with theoretical predictions
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