El Teorema de Brouwer y el Teorema del Ángulo agudo de Lions: aplicaciones

La teoría de los teoremas de punto fijo es una herramienta sumamente importante en matemática y sus aplicaciones. En ese contexto, el Teorema del punto fijo de Brouwer es uno de los resultados más relevantes por la simplicidad de su enunciado y su amplia aplicabilidad, sin embargo las demostraciones conocidas de este teorema son bastante complicadas. En este trabajo se realiza una demostración analítica, simple y didáctica del teorema de Brouwer, siguiendo la línea de John W. Milnor. Como corolario se obtiene el teorema del ángulo agudo de J.L. Lions, particularmente aplicado a la solución de sistemas algebraicos no lineales. Finalmente esta tesis concluye dando diversas aplicaciones

Estudio del incremento en la recuperación y calidad del concentrado de ZN en la flotación polimetálica en el distrito de Yarusyacan – Cerro de Pasco

Estudia el incremento del grado y recuperación del concentrado de Zn, a partir de un preconcentrado sulfurado en el proceso de flotación, determinando los parámetros de dosificación de reactivos, se ha procedido hacer un bloque de pruebas a nivel laboratorio y desarrollar la mejor performance metalúrgica. Para este estudio se cuenta con una muestra representativa tomada a lo largo de las guardias de la planta concentradora, la ley promedio de cabeza es de: Espuma de la 2da. Limpieza Zn: Ag Oz/TM: 3.15 Pb %: 1.09 Zn %: 40.89 Cu %: 1.46 Fe %: 11.77 Bi %: 0.131 La caracterización de la muestra se llevó a cabo con el microscopio óptico polarizado, los resultados de la caracterización indicaron presencia en el concentrado de Zn, contenidos de Cuarzo, Pirita, Pirrotita, Esfalerita (Blenda - Marmatita), Silicatos de (CaAlFe), Silicatos de (AlK), Carbonatos de calcio, calcopirita, óxidos e hidróxidos de hierro y galena. La ley promedio de concentrado final es de 51.5% Zn, en base a la caracterización se dirigió el estudio en la etapa de tercera limpieza Cleaner, se pasó al muestreo con un lapso de 30 min por 4 horas en 4 guardias para realizar pruebas representativas en el laboratorio en la cual se utilizó el Cuprocianuro como reactivo polimetálico secundarios y combinación de otros reactivos tales como: Cal, Dextrina, Quebracho. Se determinó el reactivo idóneo con el CuproCianuro alcanzando leyes de: Prueba 4 Grado Zn%: 52.24 Recup. Zn%: 73.80 Cabeza Zn%: 47.03 FM: 81.98 Prueba 5 Grado Zn%: 52.52 Recup. Zn%: 72.00 Cabeza Zn%: 47.00 FM: 80.46 Tomando como parte del estudio de la presente tesis, las variables dosificación del Cuprocianuro: 30g/TM, 35g/TM, 45g/TM, 50g/TM y dosificación del reactivo de flotación en la tercera Limpieza Cleaner. En base a los resultados de la caracterización se llevaron a cabo las pruebas metalúrgicas de flotación cleaner en la planta concentradora, adicionando el Cuprocianuro con: 40gr/TM, obteniendo un grado de 54.47%, recuperación de 69.20%, con un Factor metalúrgico (F.M) de 80.7

Evaluación de las modalidades de hurto de energía eléctrica en suministros de baja tensión para la reducción de pérdidas no técnicas en la provincia de Andahuaylas

El presente trabajo intitulado “Evaluación de las modalidades de hurto de energía eléctrica en suministros de baja tensión para la reducción de pérdidas no técnicas en la provincia de Andahuaylas”, se propone con la siguiente estructura: En el Capítulo I, se abordan los aspectos generales del trabajo de tesis la cual desarrolla la Introducción de la tesis, mostrando los objetivos, antecedentes y justificación del tema, es decir la motivación que permita su desarrollo. En el Capítulo II, se formulará la teoría básica necesaria referente a las actividades de distribución secundaria de la energía eléctrica, se abordan los aspectos teóricos conceptuales que constituyen la base de análisis de la propuesta formulada en el que se precisan las características de los sistemas de distribución eléctrica. En el capítulo III, se aborda los aspectos de situaciones actuales referente al nivel de pérdidas no técnicas existente en la concesión de Electro Sur Este S.A.A., dando mayo énfasis a la región de Apurímac y en específico a la provincia de Andahuaylas. En el capítulo IV, se abordan el estudio de las diferentes modalidades de hurto de energía eléctrica encontradas en la provincia de Andahuaylas, así como las evaluaciones teóricas y técnicas necesarias para las detecciones de los hurtos. En el capítulo V, se aborda el estudio y análisis de las modalidades del cálculo de recupero de energía eléctrica. Finalmente, luego de presentar los capítulos antes mencionados se exponen las conclusiones y recomendaciones que conllevaron durante la realización de todo este estudio

Weaning from mechanical ventilation in intensive care units across 50 countries (WEAN SAFE): a multicentre, prospective, observational cohort study

Background Current management practices and outcomes in weaning from invasive mechanical ventilation are poorly understood. We aimed to describe the epidemiology, management, timings, risk for failure, and outcomes of weaning in patients requiring at least 2 days of invasive mechanical ventilation. Methods WEAN SAFE was an international, multicentre, prospective, observational cohort study done in 481 intensive care units in 50 countries. Eligible participants were older than 16 years, admitted to a participating intensive care unit, and receiving mechanical ventilation for 2 calendar days or longer. We defined weaning initiation as the first attempt to separate a patient from the ventilator, successful weaning as no reintubation or death within 7 days of extubation, and weaning eligibility criteria based on positive end-expiratory pressure, fractional concentration of oxygen in inspired air, and vasopressors. The primary outcome was the proportion of patients successfully weaned at 90 days. Key secondary outcomes included weaning duration, timing of weaning events, factors associated with weaning delay and weaning failure, and hospital outcomes. This study is registered with ClinicalTrials.gov, NCT03255109. Findings Between Oct 4, 2017, and June 25, 2018, 10 232 patients were screened for eligibility, of whom 5869 were enrolled. 4523 (77·1%) patients underwent at least one separation attempt and 3817 (65·0%) patients were successfully weaned from ventilation at day 90. 237 (4·0%) patients were transferred before any separation attempt, 153 (2·6%) were transferred after at least one separation attempt and not successfully weaned, and 1662 (28·3%) died while invasively ventilated. The median time from fulfilling weaning eligibility criteria to first separation attempt was 1 day (IQR 0–4), and 1013 (22·4%) patients had a delay in initiating first separation of 5 or more days. Of the 4523 (77·1%) patients with separation attempts, 2927 (64·7%) had a short wean (≤1 day), 457 (10·1%) had intermediate weaning (2–6 days), 433 (9·6%) required prolonged weaning (≥7 days), and 706 (15·6%) had weaning failure. Higher sedation scores were independently associated with delayed initiation of weaning. Delayed initiation of weaning and higher sedation scores were independently associated with weaning failure. 1742 (31·8%) of 5479 patients died in the intensive care unit and 2095 (38·3%) of 5465 patients died in hospital. Interpretation In critically ill patients receiving at least 2 days of invasive mechanical ventilation, only 65% were weaned at 90 days. A better understanding of factors that delay the weaning process, such as delays in weaning initiation or excessive sedation levels, might improve weaning success rates

Weaning from mechanical ventilation in intensive care units across 50 countries (WEAN SAFE): a multicentre, prospective, observational cohort study

Background: Current management practices and outcomes in weaning from invasive mechanical ventilation are poorly understood. We aimed to describe the epidemiology, management, timings, risk for failure, and outcomes of weaning in patients requiring at least 2 days of invasive mechanical ventilation. Methods: WEAN SAFE was an international, multicentre, prospective, observational cohort study done in 481 intensive care units in 50 countries. Eligible participants were older than 16 years, admitted to a participating intensive care unit, and receiving mechanical ventilation for 2 calendar days or longer. We defined weaning initiation as the first attempt to separate a patient from the ventilator, successful weaning as no reintubation or death within 7 days of extubation, and weaning eligibility criteria based on positive end-expiratory pressure, fractional concentration of oxygen in inspired air, and vasopressors. The primary outcome was the proportion of patients successfully weaned at 90 days. Key secondary outcomes included weaning duration, timing of weaning events, factors associated with weaning delay and weaning failure, and hospital outcomes. This study is registered with ClinicalTrials.gov, NCT03255109. Findings: Between Oct 4, 2017, and June 25, 2018, 10 232 patients were screened for eligibility, of whom 5869 were enrolled. 4523 (77·1%) patients underwent at least one separation attempt and 3817 (65·0%) patients were successfully weaned from ventilation at day 90. 237 (4·0%) patients were transferred before any separation attempt, 153 (2·6%) were transferred after at least one separation attempt and not successfully weaned, and 1662 (28·3%) died while invasively ventilated. The median time from fulfilling weaning eligibility criteria to first separation attempt was 1 day (IQR 0-4), and 1013 (22·4%) patients had a delay in initiating first separation of 5 or more days. Of the 4523 (77·1%) patients with separation attempts, 2927 (64·7%) had a short wean (≤1 day), 457 (10·1%) had intermediate weaning (2-6 days), 433 (9·6%) required prolonged weaning (≥7 days), and 706 (15·6%) had weaning failure. Higher sedation scores were independently associated with delayed initiation of weaning. Delayed initiation of weaning and higher sedation scores were independently associated with weaning failure. 1742 (31·8%) of 5479 patients died in the intensive care unit and 2095 (38·3%) of 5465 patients died in hospital. Interpretation: In critically ill patients receiving at least 2 days of invasive mechanical ventilation, only 65% were weaned at 90 days. A better understanding of factors that delay the weaning process, such as delays in weaning initiation or excessive sedation levels, might improve weaning success rates. Funding: European Society of Intensive Care Medicine, European Respiratory Society

Weaning from mechanical ventilation in intensive care units across 50 countries (WEAN SAFE): a multicentre, prospective, observational cohort study

International audienceBackground: Current management practices and outcomes in weaning from invasive mechanical ventilation are poorly understood. We aimed to describe the epidemiology, management, timings, risk for failure, and outcomes of weaning in patients requiring at least 2 days of invasive mechanical ventilation. Methods: WEAN SAFE was an international, multicentre, prospective, observational cohort study done in 481 intensive care units in 50 countries. Eligible participants were older than 16 years, admitted to a participating intensive care unit, and receiving mechanical ventilation for 2 calendar days or longer. We defined weaning initiation as the first attempt to separate a patient from the ventilator, successful weaning as no reintubation or death within 7 days of extubation, and weaning eligibility criteria based on positive end-expiratory pressure, fractional concentration of oxygen in inspired air, and vasopressors. The primary outcome was the proportion of patients successfully weaned at 90 days. Key secondary outcomes included weaning duration, timing of weaning events, factors associated with weaning delay and weaning failure, and hospital outcomes. This study is registered with ClinicalTrials.gov, NCT03255109. Findings: Between Oct 4, 2017, and June 25, 2018, 10 232 patients were screened for eligibility, of whom 5869 were enrolled. 4523 (77·1%) patients underwent at least one separation attempt and 3817 (65·0%) patients were successfully weaned from ventilation at day 90. 237 (4·0%) patients were transferred before any separation attempt, 153 (2·6%) were transferred after at least one separation attempt and not successfully weaned, and 1662 (28·3%) died while invasively ventilated. The median time from fulfilling weaning eligibility criteria to first separation attempt was 1 day (IQR 0–4), and 1013 (22·4%) patients had a delay in initiating first separation of 5 or more days. Of the 4523 (77·1%) patients with separation attempts, 2927 (64·7%) had a short wean (≤1 day), 457 (10·1%) had intermediate weaning (2–6 days), 433 (9·6%) required prolonged weaning (≥7 days), and 706 (15·6%) had weaning failure. Higher sedation scores were independently associated with delayed initiation of weaning. Delayed initiation of weaning and higher sedation scores were independently associated with weaning failure. 1742 (31·8%) of 5479 patients died in the intensive care unit and 2095 (38·3%) of 5465 patients died in hospital. Interpretation: In critically ill patients receiving at least 2 days of invasive mechanical ventilation, only 65% were weaned at 90 days. A better understanding of factors that delay the weaning process, such as delays in weaning initiation or excessive sedation levels, might improve weaning success rates. Funding: European Society of Intensive Care Medicine, European Respiratory Society