679 research outputs found

    Caracterización espacial de parámetros biofísicos de la cubierta vegetal para la validación de productos derivados mediante teledetección : aplicación de técnicas geoestadísticas

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    El objetivo principal de esta tesis doctoral ha sido el desarrollar una metodología que permita la caracterización espacial a alta resolución de los parámetros biofísicos, LAI, FVC y FAPAR a partir de medidas in-situ, para su uso como verdad-terreno en la validación directa de productos biofísicos. Por otra parte, se ha llevado a cabo la validación indirecta de los productos de baja resolución para toda la Península Ibérica.The main objective of this thesis is to develop a methodology for the validation of coarse resolution satellite products, mainly focused on vegetation products derived using the SEVIRI instrument in the context of the LSA SAF projects.the methodology is based on the characterization of high-resolution maps of biohysical variables from in-situ measurements using geoestatistics and robust statistics methods

    Desarrollo organizacional y compromiso laboral de los trabajadores de la UGEL Ventanilla 2021

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    La investigación tuvo como objetivo determinar la relación del Desarrollo Organizacional y el Compromiso Laboral de los trabajadores de la UGEL Ventanilla 2021. El tipo de investigación es básica, enfoque cuantitativo, nivel descriptivo correlacional y diseño no experimental-transeccional, se utilizó la técnica de la encuesta y como instrumento el cuestionario, validado por juicio de expertos y la confiabilidad determinada por el coeficiente Alfa de Cronbach. La muestra fue censal conformada por 79 trabajadores. Los resultados nos permiten determinar que el nivel de Desarrollo Organizacional es regular, expresado en el 67,1%, los directivos están trabajando por la mejora institucional, pero falta optimizar las políticas, la integración y adaptación de los colaboradores para el logro de los objetivos de la entidad; asimismo, el 58,2% de los trabajadores afirman que existe poco compromiso por lo que se debe seguir trabajando en la mejora de la productividad del personal, el desarrollo de sus funciones, la eficiencia en las labores encomendadas y en la identificación del trabajador para conseguir logros que favorezcan el crecimiento institucional y personal. Las conclusiones establecen un nivel de correlación positiva considerable entre la variable desarrollo organizacional y compromiso laboral (Rho 0,690 y sig =0,000)

    Mechanisms involved in the remyelinating effect of sildenafil

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    Remyelination occurs in demyelinated lesions in multiple sclerosis (MS) and pharmacological treatments that enhance this process will critically impact the long term functional outcome in the disease. Sildenafil, a cyclic GMP (cGMP)-specific phosphodiesterase 5 inhibitor (PDE5-I), is an oral vasodilator drug extensively used in humans for treatment of erectile dysfunction and pulmonary arterial hypertension. PDE5 is expressed in central nervous system (CNS) neuronal and glial populations and in endothelial cells and numerous studies in rodent models of neurological disease have evidenced the neuroprotective potential of PDE5-Is. Using myelin oligodendrocyte glycoprotein (MOG)-induced experimental autoimmune encephalomyelitis (EAE) as a MS model, we previously showed that daily administration of sildenafil starting at peak disease rapidly ameliorates clinical symptoms while administration at symptoms onset prevents disease progression. These beneficial effects of the drug involved down-regulation of adaptive and innate immune responses, protection of axons and oligodendrocytes (OLs) and promotion of remyelination. In this work we have investigated mechanisms involved in the remyelinating effect of sildenafil. Using demyelinated organotypic cerebellar slice cultures we demonstrate that sildenafil stimulates remyelination by direct effects on CNS cells in a nitric oxide (NO)-cGMP-protein kinase G (PKG)-dependent manner. We also show that sildenafil treatment enhances OL maturation and induces expression of the promyelinating factor ciliary neurotrophic factor (CNTF) in spinal cord of EAE mice and in cerebellar slice cultures. Furthermore, we demonstrate that sildenafil promotes a M2 phenotype in bone marrow derived macrophages (BMDM) and increases myelin phagocytosis in these cells and in M2 microglia/macrophages in the spinal cord of EAE mice. Taken together these data indicate that promotion of OL maturation directly or through induction of growth factor expression, regulation of microglia/macrophage inflammatory phenotype and clearance of myelin debris may be relevant mechanisms involved in sildenafil enhancement of remyelination in demyelinated tissue and further support the contention that this well tolerated drug could be useful for ameliorating MS pathology

    Fiabilidad y validez de constructo de la Escala de Estrés Percibido en estudiantes de Medicina

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    Introduction: stress is a contemporary phenomenon that affects students of Higher Education. There are no validated instruments in the Cuban context for its correct assessment.Objective: to establish the psychometric properties as a function of the reliability and construct validity of the Perceived Stress Scale in medical students of Pinar del Rio province in 2017.Methods: descriptive, cross-sectional, technological evaluation study carried out with medical students from Pinar del Rio University of Medical Sciences during 2017. A sample of 400 students from the sixth academic year of medicine studies was chosen. The application of the Perceived Stress Scale allowed obtaining information for subsequent validation in the Cuban context.Results: high values (0.84) of Cronbach's Alpha were obtained, which demonstrated reliability in the test. Factor analysis obtained two dimensions or factors, achieving adequate correlations between the items belonging to each factor.Conclusions: the Perceived Stress Scale presented adequate metric qualities when validated in the Cuban context, proving to be reliable and with a bi-factor structure in correspondence with what was stated by its original authors. Using this instrument it is possible to determine the influence of stress in the teaching process, and the academic results of the students; as well as how the teaching staff can be linked to the perception of stress by the students.Introducción: el estrés es un fenómeno contemporáneo que afecta a estudiantes de la Educación Superior, en Cuba no se encuentran instrumentos validados en el contexto nacional para su correcta evaluación.Objetivo: establecer las propiedades psicométricas en función de la fiabilidad y la validez de constructo de la Escala de Estrés Percibido en estudiantes de la carrera de Medicina de la provincia de Pinar del Río en el 2017.Métodos: estudio descriptivo, transversal, de evaluación tecnológica, realizado con estudiantes de Medicina de la Universidad de Ciencias Médicas de Pinar del Río durante el año 2017. Se trabajó con una muestra de 400 estudiantes de los seis años de la carrera. La aplicación de la Escala de Estrés Percibido permitió la obtención de información para la posterior validación en el contexto cubano.Resultados: se obtuvieron valores elevados (0,84) de Alfa de Cronbach, lo que demostró fiabilidad en el test. El análisis factorial obtuvo dos dimensiones o factores, obteniéndose correlaciones adecuadas entre los ítems pertenecientes a cada factor.Conclusiones: la Escala de Estrés Percibido presentó cualidades métricas adecuadas al ser validado en el contexto cubano demostrando ser fiable y con una estructura bifactorial en correspondencia con lo planteado por sus autores originales. Contar con este instrumento permite tener una herramienta para determinar la influencia del estrés en el proceso docente, los resultados académicos de los estudiantes e incluso cómo el claustro profesoral puede estar vinculado con la percepción de estrés por parte de los estudiantes

    Adopta un microorganismo

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    Memoria ID-24 Ayudas de la Universidad de Salamanca para la innovación docente, curso 2020-2021

    Mapping the Viability, Time, and Cost of Manual Borehole Drilling in Developing Regions

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    While access to water remains an issue in arid and semiarid regions across the world, aquifers have the potential to help millions of people out of poverty by providing a reliable source of drinking and irrigation water. Manual boreholes are increasingly advocated as a safe and cost-effective substitute to mechanized drilling, as well as to traditional excavation methods. This research banks on the assumption that field and remote sensing data can be integrated within a geospatial database in order to map the viability of manual boreholes based on factors such as rock type, water table depth, landforms, or water quality. The approach presents three main novelties in relation to methodological precedents: (1) outcomes are not only expressed in terms of technical feasibility, but also as a function of drilling time and cost; (2) maps refer to a specific drilling technique; and (3) results take into account borehole diameter, as this constrains both drilling time and cost. The method provides univocal outcomes that can be immediately useful for non-experts, donors, planners, or practitioners and that can be readily exported to other catchment-scale settings. Results were validated against geophysical data
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