64 research outputs found

    Estudio hidrológico e hidráulico para el diseño de un puente vehicular sobre el Río Moyocc – Cangallo – Ayacucho, 2020

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    Desempeña un estudio hidrológico e hidráulico para el estudio definitivo del diseño del puente vehicular sobre el río Moyocc del distrito de Cangallo. Para ello se determinó las propiedades del río en la sección del puente con el fin de conocer la luz hidráulica del puente, el nivel de aguas máximas extraordinarias (NAME), el borde libre recomendado y las cotas máximas de socavación. Para lograr dichos resultados se planteó cuatro capítulos. El primer capítulo presenta la introducción relacionada al tema, la importancia del proyecto, objetivos de la investigación, la identificación de problemas, la propuesta de solución, los alcances y delimitaciones del tema. El segundo capítulo detalla los antecedentes de estudios referentes al análisis hidrológico e hidráulico de puentes, las bases teóricas fundamentales y las de ingeniería que se utilizará para elaboración de los cálculos. El tercer capítulo aborda las características de la zona de investigación, la recolección de datos, que incluye la información meteorológica, cartográfica y fisiográfica de la cuenca, evaluación del estudio de suelos y cobertura vegetal. Además, detalla las consideraciones de diseño y cálculos de ingeniería ejecutados tanto para la hidrología como la hidráulica como: El análisis de precipitaciones, estimación de los caudales máximos, calibración del modelo, las características hidráulicas y el cálculo de las socavaciones. El cuarto capítulo presenta el resultado final que son los parámetros geomorfológicos de la cuenca de estudio, los resultados de los caudales de diseño, el NAME y la profundidad de socavación local, por contracción y general, el cual se expone en las conclusiones

    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

    Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

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    Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

    Inclusive J/ψ\psi production in Xe–Xe collisions at sNN\sqrt{s_{\rm NN}} = 5.44 TeV

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    Inclusive J/ψ\psi production is studied in Xe-Xe interactions at a centre-of-mass energy per nucleon pair of sNN=5.44\sqrt{s_{\rm NN}}= 5.44 TeV, using the ALICE detector at the CERN LHC. The J/ψ\psi meson is reconstructed via its decay into a muon pair, in the centre-of-mass rapidity interval 2.5<y<42.5<y<4 and down to zero transverse momentum. In this Letter, the nuclear modification factors RAAR_{\rm AA} for inclusive J/ψ\psi, measured in the centrality range 0-90% as well as in the centrality intervals 0-20% and 20-90% are presented. The RAAR_{\rm AA} values are compared to previously published results for Pb-Pb collisions at sNN=5.02\sqrt{s_{\rm NN}}= 5.02 TeV and to the calculation of a transport model. A good agreement is found between Xe-Xe and Pb-Pb results as well as between data and the model

    Anisotropic flow in Xe-Xe collisions at sNN=5.44\mathbf{\sqrt{s_{\rm{NN}}} = 5.44} TeV

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    The first measurements of anisotropic flow coefficients vn for mid-rapidity charged particles in Xe–Xe collisions at sNN=5.44 TeV are presented. Comparing these measurements to those from Pb–Pb collisions at sNN=5.02 TeV, v2 is found to be suppressed for mid-central collisions at the same centrality, and enhanced for central collisions. The values of v3 are generally larger in Xe–Xe than in Pb–Pb at a given centrality. These observations are consistent with expectations from hydrodynamic predictions. When both v2 and v3 are divided by their corresponding eccentricities for a variety of initial state models, they generally scale with transverse density when comparing Xe–Xe and Pb–Pb, with some deviations observed in central Xe–Xe and Pb–Pb collisions. These results assist in placing strong constraints on both the initial state geometry and medium response for relativistic heavy-ion collisions

    Energy dependence of exclusive J/ψ\mathrm {J}/\psi photoproduction off protons in ultra-peripheral p–Pb collisions at sNN=5.02\sqrt{s_{\mathrm {\scriptscriptstyle NN}}} = 5.02 TeV

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    International audienceThe ALICE Collaboration has measured the energy dependence of exclusive photoproduction of J/ψ\mathrm {J}/\psi vector mesons off proton targets in ultra–peripheral p–Pb collisions at a centre-of-mass energy per nucleon pair sNN=5.02\sqrt{s_\mathrm{NN}} = 5.02 TeV. The e+^+ e^- and μ+μ\mu ^+\mu ^- decay channels are used to measure the cross section as a function of the rapidity of the J/ψ\mathrm {J}/\psi in the range 2.5<y<2.7-2.5< y < 2.7 , corresponding to an energy in the γ\gamma p centre-of-mass in the interval 40<Wγp<55040< W_{\gamma \mathrm {p}}<550 GeV. The measurements, which are consistent with a power law dependence of the exclusive J/ψ\mathrm {J}/\psi photoproduction cross section, are compared to previous results from HERA and the LHC and to several theoretical models. They are found to be compatible with previous measurements

    Study of J/ψ\psi azimuthal anisotropy at forward rapidity in Pb-Pb collisions at sNN=5.02 \sqrt{s_{\mathrm{NN}}}=5.02 TeV

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    International audienceThe second (v2_{2}) and third (v3_{3}) flow harmonic coefficients of J/ψ mesons are measured at forward rapidity (2.5 < y < 4.0) in Pb-Pb collisions at sNN=5.02 \sqrt{s_{\mathrm{NN}}}=5.02 TeV with the ALICE detector at the LHC. Results are obtained with the scalar product method and reported as a function of transverse momentum, pT_{T}, for various collision centralities. A positive value of J/ψ v3_{3} is observed with 3.7σ significance. The measurements, compared to those of prompt D0^{0} mesons and charged particles at mid-rapidity, indicate an ordering with vn_{n}(J/ψ) < vn_{n}(D0^{0}) < vn_{n}(h±^{±}) (n = 2, 3) at low and intermediate pT_{T} up to 6 GeV/c and a convergence with v2_{2}(J/ψ) ≈ v2_{2}(D0^{0}) ≈ v2_{2}(h±^{±}) at high pT_{T} above 6–8 GeV/c. In semi-central collisions (5–40% and 10–50% centrality intervals) at intermediate pT_{T} between 2 and 6 GeV/c, the ratio v3_{3}/v2_{2} of J/ψ mesons is found to be significantly lower (4.6σ) with respect to that of charged particles. In addition, the comparison to the prompt D0^{0}-meson ratio in the same pT_{T} interval suggests an ordering similar to that of the v2_{2} and v3_{3} coefficients. The J/ψ v2_{2} coefficient is further studied using the Event Shape Engineering technique. The obtained results are found to be compatible with the expected variations of the eccentricity of the initial-state geometry

    Study of J/ψ azimuthal anisotropy at forward rapidity in Pb–Pb collisions at √sNN = 5.02 TeV

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    The second (v2) and third (v3) flow harmonic coefficients of J/ψ mesons are measured at forward rapidity (2.5 < y < 4.0) in Pb-Pb collisions at sNN−−−√ = 5.02 TeV with the ALICE detector at the LHC. Results are obtained with the scalar product method and reported as a function of transverse momentum, pT, for various collision centralities. A positive value of J/ψ v3 is observed with 3.7σ significance. The measurements, compared to those of prompt D0 mesons and charged particles at mid-rapidity, indicate an ordering with vn(J/ψ) <vn(D0) <vn(h±) (n = 2, 3) at low and intermediate pT up to 6 GeV/c and a convergence with v2(J/ψ) ≈v2(D0) ≈v2(h±) at high pT above 6-8 GeV/c. In semi-central collisions (5-40% and 10-50% centrality intervals) at intermediate pT between 2 and 6 GeV/c, the ratio v3/v2 of J/ψ mesons is found to be significantly lower (4.6σ) with respect to that of charged particles. In addition, the comparison to the prompt D0-meson ratio in the same pT interval suggests an ordering similar to that of the v2 and v3 coefficients. The J/ψ v2 coefficient is further studied using the Event Shape Engineering technique. The obtained results are found to be compatible with the expected variations of the eccentricity of the initial-state geometry
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