63 research outputs found

    A multistage graph-based procedure for solving a just-in-time flexible job-shop scheduling problem with machine and time-dependent processing costs

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    This paper deals with a new flexible job-shop scheduling problem in which the objective function to be minimised is the sum of the earliness and tardiness costs of the jobs and the costs of the operations required to perform the jobs, the latter depending on the machine and the time interval in which they are performed (as happens in many countries with the costs of electric power or those of manpower). We formalise the problem with a mathematical model and we propose a heuristic procedure that is based primarily on constructing a multistage graph and finding in it the shortest path from the source to the sink. We also describe the generation of the data-set used in an extensive computational experiment and expose and analyse the obtained results.Peer ReviewedPostprint (author's final draft

    Habilidades Básicas del Pensamiento como Preámbulo Epistemológico al Procesamiento Analítico de la Información en la Enseñanza Científica Universitaria

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    The human evolutionary process has appeared as a product of the changes that were generated with bipedalism, the most important being the development of a complex brain structure, which added to its adaptations, the ability to reason. The development of complex thought processes gave him the opportunity to give name and meaning to everything we know today. We can affirm then that processes such as observation, comparison, classification and ordering are being executed without discriminating or separating each one of these, and even without being aware of what they are generating. For renowned authors, specialists in different disciplines and in theories of information processing, this situation becomes notable when a progressive deterioration of the cognitive abilities of our young people is observed, which makes it necessary to propose educational models that teach thinking and strengthening The purpose of this article is to analyze the epistemological context that pepper basic thinking skills, as a sine qua non requirement leading to the strengthening of analytical skills and processes that review the teaching of science, a university level. For this, a state of the art of the constructs referring to each of these skills was made, from the most recognized metateorics and recent investigations for several disciplinary areas, which argued the felt need to incorporate this basic cognitive and analytical stimulation to University courses, especially those related to the teaching of science.El proceso evolutivo humano, ha aparecido como producto de los cambios que se generaron con el bipedalismo, siendo el más importante el desarrollo de una estructura cerebral compleja, que adicionó a sus adaptaciones, la capacidad de raciocinio. El desarrollo de procesos complejos del pensamiento le brindó la oportunidad de dar nombre y sentido a todo lo que hoy conocemos. Podemos afirmar entonces que, procesos como la observación, comparación, clasificación y ordenamiento se vienen ejecutando sin discriminar o separar cada uno de estos, e incluso, sin tener consciencia en que se están generando. Para reconocidos autores, especialistas en las diferentes disciplinas y en teorías de procesamiento de la información, esta situación se hace notable cuando se observa un progresivo desmejoramiento de las capacidades cognitivas de nuestros jóvenes, lo que hace necesario proponer modelos educativos que enseñen a pensar y a fortalecer el pensamiento. El presente artículo tiene como propósito analizar el contexto epistemológico que cimienta a las habilidades básicas del pensamiento, como un requerimiento sine qua non conducente al fortalecimiento de las destrezas y procesos analíticos que revisten la enseñanza de las ciencias, a nivel universitario. Para ello, se realizó un estado del arte de los constructos referentes a cada una de estas habilidades, desde los metateóricos más reconocidos y las investigaciones recientes para varias áreas disciplinares, lo que permitió argumentar la sentida necesidad de incorporar esta estimulación cognitiva básica y analítica a los currículos universitarios, sobre todos aquellos relacionados con la enseñanza de la ciencia

    Factores asociados al desempeño académico universitario: tendencias geográficas, temporales y temáticas

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    The aim of this literature review was to identify the factors that influence university academic performance. The methodology consisted of carrying out a systematic review of the literature in Web of Science (including Scielo) and Scopus, with the help of the Citavi 6 bibliographic manager and the MaxQDA 2020 qualitative data analysis software. The search yielded 1491 articles including the categories academic performance, academic achievement, university students. Of the 1491, one third were excluded based on socioeconomic, cultural and educational criteria. It was concluded that academic performance is a complex phenomenon associated with psychological and pedagogical factors; however, in recent years there has been a rise in discourses and arguments from psychology and administration to the detriment of analyses of social and economic factors.El objetivo de esta revisión bibliográfica fue identificar los factores que inciden en el desempeño académico universitario. La metodología consistió en llevar a cabo una revisión sistemática de la literatura en Web of Science (incluye Scielo) y Scopus, con ayuda del gestor bibliográfico Citavi 6 y el software de análisis de datos cualitativos MaxQDA 2020. La búsqueda reportó 1491 artículos que incluyen las categorías academic performance, academic achievement, university students. De los 1491 se excluyó una tercera parte, según los criterios socioeconómicos, culturales y educativos. Se concluyó que el rendimiento académico es un fenómeno complejo asociado a factores psicológicos y pedagógicos; sin embargo, en los últimos años se observa un auge de los discursos y argumentos provenientes de la psicología y la administración en detrimento de los análisis de los factores sociales y económicos

    Efficacy of Albumin Treatment for Patients with Cirrhosis and Infections Unrelated to Spontaneous Bacterial Peritonitis

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    Background & aims: We performed a randomized trial to determine whether albumin should be administered to patients with infections unrelated to spontaneous bacterial peritonitis (SBP). Methods: We performed a multicenter, open-label trial in which 118 patients with cirrhosis, non-SBP infections, and additional risk factors for poor outcome were randomly assigned to receive antibiotics plus albumin (study group; n = 61) or antibiotics alone (control group; n = 57). The primary outcome was in-hospital mortality; secondary outcomes were effect of albumin on disease course. Results: There were no significant differences at baseline between groups in results from standard laboratory tests, serum markers of inflammation, circulatory dysfunction, or liver severity scores. However, the combined prevalence of acute on chronic liver failure (ACLF) and kidney dysfunction was significantly higher in the study group (44.3% vs 24.6% in the control group; P = .02), indicating greater baseline overall severity. There was no significant difference in the primary outcome between groups (13.1% in the study group vs 10.5% in the control group; P = .66). Circulatory and renal functions improved in only the study group. A significantly higher proportion of patients in the study group had resolution of ACLF (82.3% vs 33.3% in the control group; P = .03). A significantly lower proportion of patients in the study group developed nosocomial infections (6.6% vs 24.6% in the control group; P = .007). Conclusions: In a randomized trial of patients with advanced cirrhosis and non-SBP infections, in-hospital mortality was similar between those who received albumin plus antibiotics vs those who received only antibiotics (controls). However, patients given albumin were sicker at baseline and, during the follow-up period, a higher proportion had ACLF resolution and a lower proportion had nosocomial infections. ClinicalTrials.gov no: NCT02034279

    Effects of Albumin Treatment on Systemic and Portal Hemodynamics and Systemic Inflammation in Patients With Decompensated Cirrhosis

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    BACKGROUND & AIMS: We investigated the effect of albumin treatment (20% solution) on hypoalbuminemia, cardiocirculatory dysfunction, portal hypertension, and systemic inflammation in patients with decompensated cirrhosis with and without bacterial infections. METHODS: We performed a prospective study to assess the effects of long-term (12 weeks) treatment with low doses (1 g/kg body weight every 2 weeks) and high doses (1.5 g/kg every week) of albumin on serum albumin, plasma renin, cardiocirculatory function, portal pressure, and plasma levels of cytokines, collecting data from 18 patients without bacterial infections (the Pilot-PRECIOSA study). We also assessed the effect of short-term (1 week) treatment with antibiotics alone vs the combination of albumin plus antibiotics (1.5 g/kg on day 1 and 1 g/kg on day 3) on plasma levels of cytokines in biobanked samples from 78 patients with bacterial infections included in a randomized controlled trial (INFECIR-2 study). RESULTS: Circulatory dysfunction and systemic inflammation were extremely unstable in many patients included in the Pilot-PRECIOSA study; these patients had intense and reversible peaks in plasma levels of renin and interleukin 6. Long-term high-dose albumin, but not low-dose albumin, was associated with normalization of serum level of albumin, improved stability of the circulation and left ventricular function, and reduced plasma levels of cytokines (interleukin 6, granulocyte colony-stimulating factor, interleukin 1 receptor antagonist, and vascular endothelial growth factor) without significant changes in portal pressure. The immune-modulatory effects of albumin observed in the Pilot-PRECIOSA study were confirmed in the INFECIR-2 study. In this study, patients given albumin had significant reductions in plasma levels of cytokines. CONCLUSIONS: In an analysis of data from 2 trials (Pilot-PRECIOSA study and INFECIR-2 study), we found that albumin treatment reduced systemic inflammation and cardiocirculatory dysfunction in patients with decompensated cirrhosis. These effects might be responsible for the beneficial effects of albumin therapy on outcomes of patients with decompensated cirrhosis. ClinicalTrials.gov, Numbers: NCT00968695 and NCT03451292

    New insights into the genetic etiology of Alzheimer's disease and related dementias

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    Characterization of the genetic landscape of Alzheimer's disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/'proxy' AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele

    Hyperoxemia and excess oxygen use in early acute respiratory distress syndrome : Insights from the LUNG SAFE study

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    Publisher Copyright: © 2020 The Author(s). Copyright: Copyright 2020 Elsevier B.V., All rights reserved.Background: Concerns exist regarding the prevalence and impact of unnecessary oxygen use in patients with acute respiratory distress syndrome (ARDS). We examined this issue in patients with ARDS enrolled in the Large observational study to UNderstand the Global impact of Severe Acute respiratory FailurE (LUNG SAFE) study. Methods: In this secondary analysis of the LUNG SAFE study, we wished to determine the prevalence and the outcomes associated with hyperoxemia on day 1, sustained hyperoxemia, and excessive oxygen use in patients with early ARDS. Patients who fulfilled criteria of ARDS on day 1 and day 2 of acute hypoxemic respiratory failure were categorized based on the presence of hyperoxemia (PaO2 > 100 mmHg) on day 1, sustained (i.e., present on day 1 and day 2) hyperoxemia, or excessive oxygen use (FIO2 ≥ 0.60 during hyperoxemia). Results: Of 2005 patients that met the inclusion criteria, 131 (6.5%) were hypoxemic (PaO2 < 55 mmHg), 607 (30%) had hyperoxemia on day 1, and 250 (12%) had sustained hyperoxemia. Excess FIO2 use occurred in 400 (66%) out of 607 patients with hyperoxemia. Excess FIO2 use decreased from day 1 to day 2 of ARDS, with most hyperoxemic patients on day 2 receiving relatively low FIO2. Multivariate analyses found no independent relationship between day 1 hyperoxemia, sustained hyperoxemia, or excess FIO2 use and adverse clinical outcomes. Mortality was 42% in patients with excess FIO2 use, compared to 39% in a propensity-matched sample of normoxemic (PaO2 55-100 mmHg) patients (P = 0.47). Conclusions: Hyperoxemia and excess oxygen use are both prevalent in early ARDS but are most often non-sustained. No relationship was found between hyperoxemia or excessive oxygen use and patient outcome in this cohort. Trial registration: LUNG-SAFE is registered with ClinicalTrials.gov, NCT02010073publishersversionPeer reviewe

    Monitoreo de servicios ecosistémicos en un observatorio de cafetales agroforestales. Recomendaciones para el sector cafetalero

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    Ocho años de estudio de la ecofisiología del café, a través de experimentación y de modelación y el monitoreo de los servicios del ecosistema (SE) en una gran finca cafetalera en Costa Rica, revelaron varias recomendaciones prácticas para los agricultores y los formuladores de políticas. El sistema de cultivo estudiado dentro de nuestro observatorio colaborativo (Coffee-Flux), corresponde a un sistema agroforestal (SAF) a base de café bajo la sombra de grandes árboles de Erythrina poeppigiana (16% de la cubierta del dosel). Una gran cantidad de SE y limitantes dependen de las propiedades locales del suelo (en este caso Andisoles), especialmente de la erosión/infiltración, el agua/carbono y la capacidad de almacenamiento de nutrientes. Por lo tanto, para la evaluación de SE, el tipo de suelo es crucial. Una densidad adecuada de árboles de sombra (bastante baja aquí por la condición de libre crecimiento), redujo la severidad de las enfermedades de las hojas con la posibilidad de reducir el uso de plaguicidas y fungicidas. Un inventario simple del área basal en el collar de las plantas de café permitió estimar la biomasa subterránea y la edad promedio de la plantación, para juzgar su valor de mercado y decidir cuándo reemplazarla. Las fincas de café probablemente estén mucho más cerca de la neutralidad de C que lo indicado en el protocolo actual de C-neutralidad, que solo considera árboles de sombra, no los cafetos ni el suelo. Se proponen evaluaciones más completas, que ncluyen árboles, café, hojarasca, suelo y raíces en el balance C del SAF. Los árboles de sombra ofrecen muchos SE si se gestionan adecuadamente en el contexto local. En comparación con las condiciones a pleno sol, los árboles de sombra pueden (i) reducir la erosión laminar en un factor de 2; (ii) aumentar la fijación de N y el % de N reciclado en el sistema, reduciendo así los requisitos de fertilizantes; (iii) reducir la severidad de enfermedades de las hojas; (iv) aumentar el secuestro de C; (v) mejorar el microclima y (vi) reducir sustancialmente los efectos del cambio climático. En nuestro estudio de caso, no se encontró ningún efecto negativo sobre el rendimiento del café

    Multiancestry analysis of the HLA locus in Alzheimer’s and Parkinson’s diseases uncovers a shared adaptive immune response mediated by HLA-DRB1*04 subtypes

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    Across multiancestry groups, we analyzed Human Leukocyte Antigen (HLA) associations in over 176,000 individuals with Parkinson’s disease (PD) and Alzheimer’s disease (AD) versus controls. We demonstrate that the two diseases share the same protective association at the HLA locus. HLA-specific fine-mapping showed that hierarchical protective effects of HLA-DRB1*04 subtypes best accounted for the association, strongest with HLA-DRB1*04:04 and HLA-DRB1*04:07, and intermediary with HLA-DRB1*04:01 and HLA-DRB1*04:03. The same signal was associated with decreased neurofibrillary tangles in postmortem brains and was associated with reduced tau levels in cerebrospinal fluid and to a lower extent with increased Aβ42. Protective HLA-DRB1*04 subtypes strongly bound the aggregation-prone tau PHF6 sequence, however only when acetylated at a lysine (K311), a common posttranslational modification central to tau aggregation. An HLA-DRB1*04-mediated adaptive immune response decreases PD and AD risks, potentially by acting against tau, offering the possibility of therapeutic avenues
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