1,988 research outputs found

    Analysis of acoustic noise spectrum of domestic induction heating systems controlled by phase-accumulator modulators

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    In domestic induction heating (IH) applications, the modulation technique applied to the inverter has a high influence on the acoustic noise emissions. These noise emissions must be avoided since they may be audible and annoying to the final user. This paper analyzes the acoustic noise emissions that appear when a series half-bridge resonant inverter is operated with a phase-accumulator based modulator. This modulation technique has the advantage of operating in the frequency domain, and it is compared with the classical PWM modulator regarding the audible noise generated. The frequencies of the tones in the acoustic noise spectrum are theoretically calculated from the parameters of the phaseaccumulator based modulator. The SFM (Spectral Flatness Measure) is used to quantify the number of cases in which tones are generated by the modulation. Two techniques are applied to the phase-accumulator based modulator and their effect is tested. Theoretical results are experimentally verified

    Survival of infants born with esophageal atresia among 24 international birth defects surveillance programs

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    Background: Esophageal atresia (EA) affects around 2.3–2.6 per 10,000 births world-wide. Infants born with this condition require surgical correction soon after birth. Most survival studies of infants with EA are locally or regionally based. We aimed to describe survival across multiple world regions. Methods: We included infants diagnosed with EA between 1980 and 2015 from 24 birth defects surveillance programs that are members of the International Clearinghouse for Birth Defects Surveillance and Research. We calculated survival as the proportion of liveborn infants alive at 1 month, 1- and 5-years, among all infants with EA, those with isolated EA, those with EA and additional anomalies or EA and a chromosomal anomaly or genetic syndrome. We also investigated trends in survival over the decades, 1980s–2010s. Results: We included 6,466 liveborn infants with EA. Survival was 89.4% (95% CI 88.1–90.5) at 1-month, 84.5% (95% CI 83.0–85.9) at 1-year and 82.7% (95% CI 81.2–84.2) at 5-years. One-month survival for infants with isolated EA (97.1%) was higher than for infants with additional anomalies (89.7%) or infants with chromosomal or genetic syndrome diagnoses (57.3%) with little change at 1- and 5-years. Survival at 1 month improved from the 1980s to the 2010s, by 6.5% for infants with isolated EA and by 21.5% for infants with EA and additional anomalies. Conclusions: Almost all infants with isolated EA survived to 5 years. Mortality was higher for infants with EA and an additional anomaly, including chromosomal or genetic syndromes. Survival improved from the 1980s, particularly for those with additional anomalies

    Propuesta de mejora del Sistema Interno de Garantía de Calidad de la Facultad de Medicina

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    La garantía de calidad en el ámbito universitario puede considerarse como la atención sistemática, estructurada y continua a las titulaciones ofertadas. La garantía de calidad se compromete a poner en marcha los medios que aseguren y demuestren la calidad de los programas formativos que se desarrollan en cada una de las titulaciones ofrecidas por la Universidad y así cumplir con la obligación que tiene con la sociedad. El presente proyecto nace como fruto de la responsabilidad adquirida para el cumplimiento de las funciones encomendadas y, con el objetivo de seguir adoptando una estrategia de mejora continua de la calidad de la docencia y satisfacción de los colectivos implicados en el proceso de enseñanza-aprendizaje (Profesorado, Estudiantes y PAS)

    Consumo de drogas ilegales, apoyo familiar y factores relacionadosen estudiantes universitarios. Un estudio transversal basado en datosdel Proyecto uniHcos

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    Objective: To assess the prevalence of illegal drug use in college students on any previous occasion, duringthe previous year and the previous month, and to analyze the relationship between illegal drug use andfamily support and other factors.Methods: A cross-sectional study using data from students participating in the uniHcos project (n = 3767)was conducted. The prevalence and age of onset of consumption of cannabis, non-prescription sedatives,stimulants and depressants was evaluated. Polyconsumption was also assessed. The independent vari-ables were: family support, age, residence, and employment status. To determine the factors related todrug use multivariate logistic regression models stratified by gender were fitted.Results: Differences between men and women in prevalence of illegal drug use except non-prescriptionsedatives were observed. In both genders, less family support was associated with higher consumptionof all drugs, except depressants, and with polyconsumption. To be studying and looking for work wasrelated to cannabis and stimulant use and to polyconsumption among women, but only to cannabis useamong men.Conclusions: These results support the notion that the start of university studies is a particularly relevantstage in the onset of illegal drug use and its prevention, and that consumption may be especially associatedwith family support.Objetivo: Evaluar la prevalencia del consumo de drogas ilegales en estudiantes universitarios y analizarla relación entre dicho consumo, el apoyo familiar y otros factores.Método: Se realizó un dise?no transversal basado en datos de participantes en el proyecto uniHcos (n =3767). Se evaluaron la prevalencia y la edad de inicio del consumo de cannabis, tranquilizantes sin receta,estimulantes y depresores, y el policonsumo. Como variables independientes se consideraron el apoyofamiliar, la edad, la residencia y la situación laboral. Para la determinación de los factores asociados alconsumo de drogas se ajustaron modelos de regresión logística estratificados por sexo.Resultados: Se observaron diferencias entre hombres y mujeres en la prevalencia del consumo de todaslas drogas ilegales, excepto tranquilizantes sin receta. En ambos sexos, cuanto peor apoyo familiar, mayorconsumo de todas las drogas, excepto depresores y policonsumo. Encontrarse estudiando y buscandotrabajo se relacionó con el consumo de cannabis, estimulantes y policonsumo en las mujeres, y solo concannabis en los hombres.Conclusiones: Los resultados de este estudio aportan nueva evidencia a favor de que el inicio de la etapauniversitaria es un momento de especial relevancia en el inicio del consumo de drogas ilegales y suprevención, pudiendo este consumo estar especialmente relacionado con el apoyo familiar

    Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

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    This paper presents measurements of the W+μ+νW^+ \rightarrow \mu^+\nu and WμνW^- \rightarrow \mu^-\nu cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13

    Measurements of fiducial and differential cross sections for Higgs boson production in the diphoton decay channel at s√=8 TeV with ATLAS

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    Measurements of fiducial and differential cross sections are presented for Higgs boson production in proton-proton collisions at a centre-of-mass energy of s√=8 TeV. The analysis is performed in the H → γγ decay channel using 20.3 fb−1 of data recorded by the ATLAS experiment at the CERN Large Hadron Collider. The signal is extracted using a fit to the diphoton invariant mass spectrum assuming that the width of the resonance is much smaller than the experimental resolution. The signal yields are corrected for the effects of detector inefficiency and resolution. The pp → H → γγ fiducial cross section is measured to be 43.2 ±9.4(stat.) − 2.9 + 3.2 (syst.) ±1.2(lumi)fb for a Higgs boson of mass 125.4GeV decaying to two isolated photons that have transverse momentum greater than 35% and 25% of the diphoton invariant mass and each with absolute pseudorapidity less than 2.37. Four additional fiducial cross sections and two cross-section limits are presented in phase space regions that test the theoretical modelling of different Higgs boson production mechanisms, or are sensitive to physics beyond the Standard Model. Differential cross sections are also presented, as a function of variables related to the diphoton kinematics and the jet activity produced in the Higgs boson events. The observed spectra are statistically limited but broadly in line with the theoretical expectations

    Search for squarks and gluinos in events with isolated leptons, jets and missing transverse momentum at s√=8 TeV with the ATLAS detector

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    The results of a search for supersymmetry in final states containing at least one isolated lepton (electron or muon), jets and large missing transverse momentum with the ATLAS detector at the Large Hadron Collider are reported. The search is based on proton-proton collision data at a centre-of-mass energy s√=8 TeV collected in 2012, corresponding to an integrated luminosity of 20 fb−1. No significant excess above the Standard Model expectation is observed. Limits are set on supersymmetric particle masses for various supersymmetric models. Depending on the model, the search excludes gluino masses up to 1.32 TeV and squark masses up to 840 GeV. Limits are also set on the parameters of a minimal universal extra dimension model, excluding a compactification radius of 1/R c = 950 GeV for a cut-off scale times radius (ΛR c) of approximately 30

    Evidence for the Higgs-boson Yukawa coupling to tau leptons with the ATLAS detector

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    Results of a search for H → τ τ decays are presented, based on the full set of proton-proton collision data recorded by the ATLAS experiment at the LHC during 2011 and 2012. The data correspond to integrated luminosities of 4.5 fb−1 and 20.3 fb−1 at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV respectively. All combinations of leptonic (τ → `νν¯ with ` = e, µ) and hadronic (τ → hadrons ν) tau decays are considered. An excess of events over the expected background from other Standard Model processes is found with an observed (expected) significance of 4.5 (3.4) standard deviations. This excess provides evidence for the direct coupling of the recently discovered Higgs boson to fermions. The measured signal strength, normalised to the Standard Model expectation, of µ = 1.43 +0.43 −0.37 is consistent with the predicted Yukawa coupling strength in the Standard Model

    Search for squarks and gluinos with the ATLAS detector in final states with jets and missing transverse momentum using √s=8 TeV proton-proton collision data

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    A search for squarks and gluinos in final states containing high-p T jets, missing transverse momentum and no electrons or muons is presented. The data were recorded in 2012 by the ATLAS experiment in s√=8 TeV proton-proton collisions at the Large Hadron Collider, with a total integrated luminosity of 20.3 fb−1. Results are interpreted in a variety of simplified and specific supersymmetry-breaking models assuming that R-parity is conserved and that the lightest neutralino is the lightest supersymmetric particle. An exclusion limit at the 95% confidence level on the mass of the gluino is set at 1330 GeV for a simplified model incorporating only a gluino and the lightest neutralino. For a simplified model involving the strong production of first- and second-generation squarks, squark masses below 850 GeV (440 GeV) are excluded for a massless lightest neutralino, assuming mass degenerate (single light-flavour) squarks. In mSUGRA/CMSSM models with tan β = 30, A 0 = −2m 0 and μ > 0, squarks and gluinos of equal mass are excluded for masses below 1700 GeV. Additional limits are set for non-universal Higgs mass models with gaugino mediation and for simplified models involving the pair production of gluinos, each decaying to a top squark and a top quark, with the top squark decaying to a charm quark and a neutralino. These limits extend the region of supersymmetric parameter space excluded by previous searches with the ATLAS detector

    Measurement of χ c1 and χ c2 production with s√ = 7 TeV pp collisions at ATLAS

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    The prompt and non-prompt production cross-sections for the χ c1 and χ c2 charmonium states are measured in pp collisions at s√ = 7 TeV with the ATLAS detector at the LHC using 4.5 fb−1 of integrated luminosity. The χ c states are reconstructed through the radiative decay χ c → J/ψγ (with J/ψ → μ + μ −) where photons are reconstructed from γ → e + e − conversions. The production rate of the χ c2 state relative to the χ c1 state is measured for prompt and non-prompt χ c as a function of J/ψ transverse momentum. The prompt χ c cross-sections are combined with existing measurements of prompt J/ψ production to derive the fraction of prompt J/ψ produced in feed-down from χ c decays. The fractions of χ c1 and χ c2 produced in b-hadron decays are also measured
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