52 research outputs found
Perfil epidemiológico y adherencia terapéutica al PrEP en usuarios de un hospital de segundo nivel
No full textINTRODUCCIÓN: El VIH/SIDA es una de las enfermedades infecciosas más importantes
y prevalentes en todo el mundo. Según el informe de ONUSIDA, en 2021 había 38,4
millones de personas que viven con VIH en todo el mundo, y se registraron 1,5 millones
de nuevas infecciones por VIH ese mismo año, 650 mil personas murieron por
enfermedades relacionadas al SIDA. La profilaxis Pre-exposición (PrEP) es una
estrategia de prevención de la infección por VIH que consiste en el uso diario de
medicamentos antirretrovirales por personas que no tiene VIH pero que están en riesgo
elevado de adquirirlo. OBJETIVO: Determinar las características epidemiológicas y nivel
adherencia terapéutica a PrEP en usuarios de un Hospital de segundo nivel. MATERIAL
Y MÉTODOS: Se realizó un estudio descriptivo, observacional y transversal. Se exhortó
a participar del estudio a derechohabientes de un hospital de segundo nivel, usuarios de
PrEP. El tamaño de muestra se calculó con un nivel de confianza de 95% arrojando
muestra de 58 usuarios; se aplicó instrumento Morisky-Green. Todos los datos
recopilados fueron analizados con el programa estadístico SPSS ver. 26 español.
RESULTADOS: Se analizó a 58 pacientes usuarios de PrEP con una edad promedio de
28 años, el 100% sexo masculino, el 41.4% de la población de estudio con nivel de
escolaridad: licenciatura; estado civil 67.2% solteros, 79.3% homosexuales. Se obtuvo
que en el grupo estudiado el nivel de adherencia terapéutica en usuarios de PrEP es
media en 79.3% y solo un 12.1% es buena, un 8.6% de la adherencia es malo, en la
valoración global se identificó que la educación al paciente es vital para la adecuada
adherencia. CONCLUSIONES: El bajo porcentaje de adherencia subraya la urgencia de
intervenciones destinadas a mejorar la adherencia y, por ende, la eficacia de la PrEP.
Informar a los usuarios sobre la eficacia preventiva y diseñar estrategias de salud pública específicas para esta población son esenciales para fortalecer la salud sexual y prevenir la propagación de enfermedades infecciosas en este grupo demográfico.InvestigadoresEstudiante
The ATLAS Inner Detector Trigger performance in pp collisions at 13 TeV during LHC Run 2
Get PDFThe design and performance of the inner detector trigger for the high level
trigger of the ATLAS experiment at the Large Hadron Collider during the 2016-18
data taking period is discussed. In 2016, 2017, and 2018 the ATLAS detector
recorded 35.6 fb, 46.9 fb, and 60.6 fb respectively of
proton-proton collision data at a centre-of-mass energy of 13 TeV. In order to
deal with the very high interaction multiplicities per bunch crossing expected
with the 13 TeV collisions the inner detector trigger was redesigned during the
long shutdown of the Large Hadron Collider from 2013 until 2015. An overview of
these developments is provided and the performance of the tracking in the
trigger for the muon, electron, tau and -jet signatures is discussed. The
high performance of the inner detector trigger with these extreme interaction
multiplicities demonstrates how the inner detector tracking continues to lie at
the heart of the trigger performance and is essential in enabling the ATLAS
physics programme.Comment: 81 pages in total, author list starting page 65, 44 figures, 0
tables. All figures including auxiliary figures are available at
https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/TRIG-2019-03
Search for new phenomena in events with an energetic jet and missing transverse momentum in collisions at TeV with the ATLAS detector
Get PDFResults of a search for new physics in final states with an energetic jet and large missing transverse momentum are reported. The search uses proton-proton collision data corresponding to an integrated luminosity of 139 fb at a center-of-mass energy of 13 TeV collected in the period 2015-2018 with the ATLAS detector at the Large Hadron Collider. Compared to previous publications, in addition to an increase of almost a factor of four in the data size, the analysis implements a number of improvements in the signal selection and the background determination leading to enhanced sensitivity. Events are required to have at least one jet with transverse momentum above 150 GeV and no reconstructed leptons (, or ) or photons. Several signal regions are considered with increasing requirements on the missing transverse momentum starting at 200 GeV. Overall agreement is observed between the number of events in data and the Standard Model predictions. Model-independent confidence-level limits on visible cross sections for new processes are obtained in the range between 736 fb and 0.3 fb. Results are also translated into improved exclusion limits in models with pair-produced weakly interacting dark-matter candidates, large extra spatial dimensions, supersymmetric particles in several compressed scenarios, axion-like particles, and new scalar particles in dark-energy-inspired models. In addition, the data are translated into bounds on the invisible branching ratio of the Higgs boson.57 pages in total, author list starting page 41, 11 figures, 10 tables. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/EXOT-2018-0
Combination of Searches for Invisible Higgs Boson Decays with the ATLAS Experiment.
Get PDFDark matter particles, if sufficiently light, may be produced in decays of the Higgs boson. This Letter presents a statistical combination of searches for H→invisible decays where H is produced according to the standard model via vector boson fusion, Z(ℓℓ)H, and W/Z(had)H, all performed with the ATLAS detector using 36.1 fb^{-1} of pp collisions at a center-of-mass energy of sqrt[s]=13 TeV at the LHC. In combination with the results at sqrt[s]=7 and 8 TeV, an exclusion limit on the H→invisible branching ratio of 0.26(0.17_{-0.05}^{+0.07}) at 95% confidence level is observed (expected)
Measurement of the VH,H → ττ process with the ATLAS detector at 13 TeV
Get PDFA measurement of the Standard Model Higgs boson produced in association with a W or Z boson and decaying
into a pair of τ-leptons is presented. This search is based on proton-proton collision data collected at
√s = 13 TeV
by the ATLAS experiment at the LHC corresponding to an integrated luminosity of 140 fb−1. For the Higgs boson
candidate, only final states with at least one τ-lepton decaying hadronically (τ →hadrons + vτ ) are considered.
For the vector bosons, only leptonic decay channels are considered: Z → ℓℓ and W → ℓvℓ, with ℓ = e, μ. An
excess of events over the expected background is found with an observed (expected) significance of 4.2 (3.6)
standard deviations, providing evidence of the Higgs boson produced in association with a vector boson and
decaying into a pair of τ-leptons. The ratio of the measured cross-section to the Standard Model prediction is
μττ
VH = 1.28 +0.30
−0.29 (stat.) +0.25
−0.21 (syst.). This result represents the most accurate measurement of the VH(ττ) process
achieved to date
Performance and calibration of quark/gluon-jet taggers using 140 fb−1 of pp collisions at √s = 13 TeV with the ATLAS detector
Get PDFThe identification of jets originating from quarks and gluons, often referred to as quark/gluon tagging, plays an important role in various analyses performed at the Large Hadron Collider, as Standard Model measurements and searches for new particles decaying to quarks often rely on suppressing a large gluon-induced background. This paper describes the measurement of the efficiencies of quark/gluon taggers developed within the ATLAS Collaboration, using √s = 13 TeV proton–proton collision data with an integrated luminosity of 140 fb-1 collected by the ATLAS experiment. Two taggers with high performances in rejecting jets from gluon over jets from quarks are studied: one tagger is based on requirements on the number of inner-detector tracks associated with the jet, and the other combines several jet substructure observables using a boosted decision tree. A method is established to determine the quark/gluon fraction in data, by using quark/gluon-enriched subsamples defined by the jet pseudorapidity. Differences in tagging efficiency between data and simulation are provided for jets with transverse momentum between 500 GeV and 2 TeV and for multiple tagger working points
Search for new particles in final states with a boosted top quark and missing transverse momentum in proton-proton collisions at √s = 13 TeV with the ATLAS detector
Get PDFA search for events with one top quark and missing transverse momentum in the final state is presented. The fully hadronic decay of the top quark is explored by selecting events with a reconstructed boosted top-quark topology produced in association with large missing transverse momentum. The analysis uses 139 fb−1 of proton-proton collision data at a centre-of-mass energy of √s = 13 TeV recorded during 2015-2018 by the ATLAS detector at the Large Hadron Collider. The results are interpreted in the context of simplified models for Dark Matter particle production and the single production of a vector-like T quark. Without significant excess relative to the Standard Model expectations, 95% confidence-level upper limits on the corresponding cross-sections are obtained. The production of Dark Matter particles in association with a single top quark is excluded for masses of a scalar (vector) mediator up to 4.3 (2.3) TeV, assuming mχ = 1 GeV and the model couplings λq = 0.6 and λχ = 0.4 (a = 0.5 and gχ = 1). The production of a single vector-like T quark is excluded for masses below 1.8 TeV assuming a coupling to the top quark κT = 0.5 and a branching ratio for T → Zt of 25%
Search for displaced leptons in √s = 13 TeV and 13.6 TeV pp collisions with the ATLAS detector
No full textA search for leptons displaced from the primary vertex is performed with the ATLAS detector at the Large Hadron Collider. The search includes the full proton-proton collision dataset collected during Run 2 at √s = 13 TeV and a partial dataset collected during Run 3 in 2022–2023 at √s = 13.6 TeV, corresponding to integrated luminosities of 140 fb−1 and 56.3 fb−1, respectively. Final states with displaced electrons or muons are considered, and novel triggers introduced in Run 3 are employed that use large impact parameter tracking to reconstruct displaced tracks with low momentum. In addition, photon reconstruction and multivariate techniques are employed to broaden the sensitivity to channels with large background rates or highly displaced electrons, respectively. The results are consistent with the Standard Model background expectations and are used to set model-independent limits on the production of displaced electrons and muons. The analysis is also interpreted in the context of a gauge-mediated supersymmetry breaking model with pair-produced long-lived sleptons and a dark sector model with pairproduced chargino-like states. The results include 95% confidence level exclusions of selectrons with lifetimes from 4 ps to 60 ns and a mass of 150 GeV, and exclusions of selectrons, smuons, and staus with a lifetime of 0.3 ns for masses up to 740, 830, and 440 GeV, respectively. Dark charginos with masses up to 380 GeVare excluded for a mass difference with the neutral state of 40 GeV, and mass differences down to 17 GeV are excluded for dark charginos with a 100 GeV mass
Measurement of production cross-sections in the four-lepton final state in collisions at TeV with the ATLAS experiment
Get PDFThis paper reports cross-section measurements of production in collisions at TeV at the Large Hadron Collider. The data were collected by the ATLAS detector in 2022, and correspond to an integrated luminosity of 29 fb. Events in the (, ) final states are selected and used to measure the inclusive and differential cross-sections in a fiducial region defined close to the analysis selections. The inclusive cross-section is further extrapolated to the total phase space with a requirement of 66 s=13.6TeV at the Large Hadron Collider. The data were collected by the ATLAS detector in 2022, and correspond to an integrated luminosity of 29 fb−1. Events in the ZZ→4ℓ (ℓ=e, μ) final states are selected and used to measure the inclusive and differential cross-sections in a fiducial region defined close to the analysis selections. The inclusive cross-section is further extrapolated to the total phase space with a requirement of 66 <mZ< 116 GeV for both Z bosons, yielding 16.8±1.1 pb. The results are well described by the Standard Model predictions.This paper reports cross-section measurements of ZZpp\sqrt{s}=13.6^-1ZZ\rightarrow4\ell\ell = e\mu< m_Z <Z16.8 \pm 1.1$ pb. The results are well described by the Standard Model predictions
Search for top-philic heavy resonances in pp collisions at √s = 13 TeV with the ATLAS detector
Get PDFA search for the associated production of a heavy
resonance with a top-quark or a top-antitop-quark pair, and
decaying into a tt¯ pair is presented. The search uses the
data recorded by the ATLAS detector in pp collisions at
√s = 13 TeV at the Large Hadron Collider during the years
2015–2018, corresponding to an integrated luminosity of
139 fb−1. Events containing exactly one electron or muon are
selected. The two hadronically decaying top quarks from the
resonance decay are reconstructed using jets clustered with
a large radius parameter of R = 1. The invariant mass spectrum of the two top quark candidates is used to search for a
resonance signal in the range of 1.0 TeV to 3.2 TeV. The presence of a signal is examined using an approach with minimal
model dependence followed by a model-dependent interpretation. No significant excess is observed over the background
expectation. Upper limits on the production cross section
times branching ratio at 95% confidence level are provided
for a heavy Z boson based on a simplified model, for Z mass
between 1.0 TeV and 3.0 TeV. The observed (expected) limits range from 21 (14) fb to 119 (86) fb depending on the
choice of model parameters
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