802 research outputs found

    Measurement of exclusive B lifetimes in the modes B+ to J/psi K+, B+ to J/psi K*+, B0 to J/psi K*, and B0 to J/psi K0 short, and measurement of the B+/B0 lifetime ratio

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    This thesis presents the results from the measurement of the lifetimes of charged and neutral B mesons in four final statesin proton-antiproton collisions at a center-of-mass energy of 1.96 TeV using 195 inverse-picobarns of data collected with the CDF detector at the Fermilab Tevatron Collider. The proper decay length is estimated using the J/psi vertex in all cases to reduce the systematics in the ratio.For the Bu meson, the mean life (ctau) is determined to be 499 +- 12 +- 6 microns; for the neutral B meson (Bd), 446+-15+-8 microns. In both measurements, the first error is statistical and the second is systematic. The ratio between Bu and Bd meson lifetimes is found to be 1.119 +- 0.046(stat) +- 0.014(syst)

    Sensor láser para medir desplazamientos en marcos de reacción de 200 Toneladas

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    El presente trabajo se acota en el ·rea del an·lisis estructural en ingenierÌa, donde se ha identificado que existe como debilidad la ausencia de material did·ctico para su enseÒanza. Por ello se ha determinado como indispensable desarrollar material did·ctico que sea complemento de las pruebas destructivas de pandeo en columnas y deflexiÛn en vigas. La propuesta son sensores de desarrollo propio, para una mayor y mejor confiabilidad de los resultados en pruebas destructivas. La propuesta se justifica por el alto costo que representa realizar pruebas de deflexiÛn o pandeo mediante una instrumentaciÛn convencional con sensores LVDT, galgas extensiomÈtricas y celdas de carga. El resultado ha sido un medidor de desplazamiento vertical que emplea el sensor laser VL53L0X, el cual se integra a un equipo de cÛmputo personal mediante el software Labview, integraciÛn que permite obtener una gr·fica de desplazamiento de manera directa. La sistematizaciÛn de la experimentaciÛn permite que el reporte final se incorpore en un cuaderno de pr·cticas que recopila y estructura la experiencia de enseÒanza, para su aplicaciÛn en el aula mediante una estrategia constructivista-cognitiva asociada a la teorÌa del c·lculo estructura

    Factors associated with low back pain in healthcare workers of a referral hospital in Peru

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    Introducción: El dolor lumbar es una condición inevitable en todo el personal del rubro de la salud, con llevando desde malestar físico hasta una incapacidad funcional del individuo. Objetivo: Determinar los factores asociados a dolor lumbar entre los trabajadores sanitarios en un hospital de referencia del Perú. Metodología: El presente estudio es observacional, analítico, de corte transversal, temporalmente prospectivo, con muestreo no probabilístico. La población estuvo conformada por trabajadores sanitarios del Hospital Santa Rosa de Pueblo Libre durante el periodo de junio a diciembre del año 2022. Resultados: El análisis multivariado determinó que el ser hombre (OR: 2.818, p valor: 0.017), tener sobrepeso (OR:1.782, p valor: 0.013), demanda laboral alta (OR: 4.750, p valor: 0.026), realizar actividad física (OR: 3.610, p valor: 0.031) y tener antecedentes de trauma lumbar (OR: 2.423, p valor: 0.034), fueron factores estadísticamente significativos que se asociaron al dolor lumbar. Discusión: Se pudo observar que, los factores asociados a dolor lumbar fueron el sexo masculino, el sobrepeso, la demanda laboral alta, el realizar actividad física y el antecedente de trauma lumbar. Conocer estas variables permitirá realizar esquemas y charlas preventivas para afrontar esta recurrente patologíaIntroduction: Low back pain is an unavoidable condition in all health personnel, ranging from physical discomfort to functional disability of the individual. Objective: To determine the factors associated with low back pain among health workers at a reference hospital in Peru. Methods: This study is observational, analytical, cross-sectional, temporally prospective, with non-probabilistic sampling. The population was made up of health workers from the Hospital Santa Rosa de Pueblo Libre during the period from June to December of the year 2022. Results: The multivariate analysis determined that being a man (OR: 2.818, p value: 0.017), being overweight (OR:1.782, p value: 0.013), high labor demand (OR: 4.750, p value: 0.026), performing physical (OR: 3.610, p value: 0.031) and having a history of low back trauma (OR: 2.423, p value: 0.034) were statistically significant factors associated with low back pain. Discussion: It was possible to observe that the factors associated with low back pain were the male sex, being overweight, high work demand, physical activity and a history of low back trauma. Knowing these variables will make it possible to carry out preventive schemes and talks to deal with this recurring patholog

    IV Foro Internacional de Ganadería Sustentable: conectividad ecosistémica y articulación territorial hacia la Agenda 2030

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    En este espacio plural de análisis y reflexiones, buscamos articular conceptos y posibilidades para los territorios de montaña del centro de México, dando importancia a medios de vida vinculados a la ganadería y su interacción ecosistémica, fundamentado en innovaciones, casos de éxito e iniciativas emblemáticas nacionales e internacionales. La socialización de experiencias es uno de los pilares para transitar hacia la sostenibilidad de los sistemas productivos ganaderos: compartir logros e iniciativas, crear sinergias e identificar vulnerabilidades desde distintos enfoques.GIZ, Agencia de Cooperación Aleman

    Calidad de las elecciones a titular del Ejecutivo en el Centro y Centro-occidente de México

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    Este libro, que tiene por objetivo analizar la calidad de las elecciones celebradas entre 2006 y 2011 para ocupar la titularidad del Poder Ejecutivo de las 14 entidades federativas de la República Mexicana que conforman las regiones Centro y Centro-occidente de este país, ha sido elaborado por investigadores pertenecientes a la Red Nacional de Investigación sobre la Calidad de la Democracia en México (Renicadem), la cual cuenta con un equipo de investigación en cada una de las entidades federativas del país. A su vez, esta Red constituye una de las cuatro líneas temáticas que componen la red temática del Conacyt “Sociedad civil y calidad de la democracia”. Con todo, la presente obra puede considerarse, en dos sentidos, como el resultado parcial de estudios realizados por investigadores que conforman la mencionada Renicadem. Por un lado, trata sólo de una de las varias dimensiones que esta Red ha establecido como necesarias para analizar la calidad de la democracia: la calidad electoral (otras dimensiones, que se encuentran en proceso de investigación, son calidad de vida, rendición de cuentas y Estado de derecho). También es parcial porque no abarca la totalidad de la República Mexicana, sino únicamente a las 14 entidades indicadas.UAE

    Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

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    The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

    Evolving trends in the management of acute appendicitis during COVID-19 waves. The ACIE appy II study

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    Background: In 2020, ACIE Appy study showed that COVID-19 pandemic heavily affected the management of patients with acute appendicitis (AA) worldwide, with an increased rate of non-operative management (NOM) strategies and a trend toward open surgery due to concern of virus transmission by laparoscopy and controversial recommendations on this issue. The aim of this study was to survey again the same group of surgeons to assess if any difference in management attitudes of AA had occurred in the later stages of the outbreak. Methods: From August 15 to September 30, 2021, an online questionnaire was sent to all 709 participants of the ACIE Appy study. The questionnaire included questions on personal protective equipment (PPE), local policies and screening for SARS-CoV-2 infection, NOM, surgical approach and disease presentations in 2021. The results were compared with the results from the previous study. Results: A total of 476 answers were collected (response rate 67.1%). Screening policies were significatively improved with most patients screened regardless of symptoms (89.5% vs. 37.4%) with PCR and antigenic test as the preferred test (74.1% vs. 26.3%). More patients tested positive before surgery and commercial systems were the preferred ones to filter smoke plumes during laparoscopy. Laparoscopic appendicectomy was the first option in the treatment of AA, with a declined use of NOM. Conclusion: Management of AA has improved in the last waves of pandemic. Increased evidence regarding SARS-COV-2 infection along with a timely healthcare systems response has been translated into tailored attitudes and a better care for patients with AA worldwide

    Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

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    Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

    Atrasentan and renal events in patients with type 2 diabetes and chronic kidney disease (SONAR): a double-blind, randomised, placebo-controlled trial

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    Background: Short-term treatment for people with type 2 diabetes using a low dose of the selective endothelin A receptor antagonist atrasentan reduces albuminuria without causing significant sodium retention. We report the long-term effects of treatment with atrasentan on major renal outcomes. Methods: We did this double-blind, randomised, placebo-controlled trial at 689 sites in 41 countries. We enrolled adults aged 18–85 years with type 2 diabetes, estimated glomerular filtration rate (eGFR)25–75 mL/min per 1·73 m 2 of body surface area, and a urine albumin-to-creatinine ratio (UACR)of 300–5000 mg/g who had received maximum labelled or tolerated renin–angiotensin system inhibition for at least 4 weeks. Participants were given atrasentan 0·75 mg orally daily during an enrichment period before random group assignment. Those with a UACR decrease of at least 30% with no substantial fluid retention during the enrichment period (responders)were included in the double-blind treatment period. Responders were randomly assigned to receive either atrasentan 0·75 mg orally daily or placebo. All patients and investigators were masked to treatment assignment. The primary endpoint was a composite of doubling of serum creatinine (sustained for ≥30 days)or end-stage kidney disease (eGFR <15 mL/min per 1·73 m 2 sustained for ≥90 days, chronic dialysis for ≥90 days, kidney transplantation, or death from kidney failure)in the intention-to-treat population of all responders. Safety was assessed in all patients who received at least one dose of their assigned study treatment. The study is registered with ClinicalTrials.gov, number NCT01858532. Findings: Between May 17, 2013, and July 13, 2017, 11 087 patients were screened; 5117 entered the enrichment period, and 4711 completed the enrichment period. Of these, 2648 patients were responders and were randomly assigned to the atrasentan group (n=1325)or placebo group (n=1323). Median follow-up was 2·2 years (IQR 1·4–2·9). 79 (6·0%)of 1325 patients in the atrasentan group and 105 (7·9%)of 1323 in the placebo group had a primary composite renal endpoint event (hazard ratio [HR]0·65 [95% CI 0·49–0·88]; p=0·0047). Fluid retention and anaemia adverse events, which have been previously attributed to endothelin receptor antagonists, were more frequent in the atrasentan group than in the placebo group. Hospital admission for heart failure occurred in 47 (3·5%)of 1325 patients in the atrasentan group and 34 (2·6%)of 1323 patients in the placebo group (HR 1·33 [95% CI 0·85–2·07]; p=0·208). 58 (4·4%)patients in the atrasentan group and 52 (3·9%)in the placebo group died (HR 1·09 [95% CI 0·75–1·59]; p=0·65). Interpretation: Atrasentan reduced the risk of renal events in patients with diabetes and chronic kidney disease who were selected to optimise efficacy and safety. These data support a potential role for selective endothelin receptor antagonists in protecting renal function in patients with type 2 diabetes at high risk of developing end-stage kidney disease. Funding: AbbVie

    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
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