589 research outputs found

    El manto de nieve en la península ibérica: climatología y sensibilidad a la variabilidad climática

    Get PDF
    El manto de nieve juega un papel crucial en multitud de procesos clave en la península ibérica como la hidrología, la ecología, economía o la gestión de riesgos entre muchos otros. A pesar de ello, la falta generalizada de datos observados ha imposibilitado el estudio del manto de nieve a nivel regional. Mediante el uso de modelos numéricos y teledetección se ha generado una base de datos a resolución diaria del manto de nieve que cubre el periodo comprendido entre 1980 y 2014. Esta información ha sido utilizada para realizar la primera climatología del manto de nieve de las principales cordilleras de la península ibérica, así como estudiar como la Oscilación del Atlántico Norte controla los patrones de acumulación y duración del manto. Por último, este trabajo estudia la sensibilidad del manto de nieve a los cambios esperables en el clima en las próximas décadas.Doctorado en Conservación y Uso Sostenible de Sistemas Forestale

    Modelización de la distribución de nieve en un ambiente de alta montaña (Alto Caldarés, Pirineo Central Español)

    Get PDF
    En el presente trabajo se ha realizado una modelización de la distribución de la nieve en un ambiente de alta montaña en el Pirineo Central a fin ,de conocer la influencia de las variables topográficas en la distribución de la nieve, a partir de datos obtenidos mediante tecnología LIDAR terrestre a muy larga distancia.Departamento de Producción Vegetal y Recursos ForestalesMáster en Ingeniería de Monte

    Nanoóptica: controlando la luz en la nanoescala

    Get PDF
    La localización de la luz en diversas nanoestructuras ha permitido superar los límites de la óptica convencional, posibilitando un control sin precedentes de diversos procesos optoelectrónicos. La comprensión de la interacción entre la luz y la materia en la nanoescala sienta las bases de la generación, control, y manipulación de haces de luz en espacios ínfimos, abriendo un nuevo abanico de posibilidades tecnológicas. Entre otras, la nanoóptica permite obtener imagenes nanoscópicas de nanopartículas y sustancias biológicas, transmitir señal óptica de alta densidad en dispositivos, realizar termoterapia contra células cancerígenas o mejorar las prestaciones de células solares.Peer Reviewe

    Reconstrucción 3D de órgano a partir de imágenes de Tomografía Axial Computarizada (TC) usando Matlab

    Get PDF
    The three-dimensional processing and reconstruction of anatomical regions from medical images allows the application of a set of segmentation and filtering techniques to subsequently perform volumetric reconstructions and thus generate 3D computer representations of human anatomy, which is useful in the field of medicine to facilitate the analysis of human body structures.  In this paper, a 3D reconstruction was performed from the segmentation, based on the differentiation by area, of the organ (kidney) and bone structures from a series of images from an abdominal CT. Also, we implemented an interactive interface for the visualization of the planes (frontal, sagittal and transversal). The interface that shows the different planes and also loads the 3D reconstruction that was generated in a separate process, gives the user the option to select any CT study that he has stored in his computer. This procedure, depending on the field of application, complements the interaction and analysis of anatomical structures to the physician, allowing the planning of a timely treatment that will help the preoperative analysis of complex pathologies and the formulation of surgical strategies.El procesamiento tridimensional y la reconstrucción de las regiones anatómicas a partir de imágenes médicas permiten aplicar un conjunto de técnicas de segmentación y filtrado para para realizar posteriormente reconstrucciones volumétricas y así generar representaciones computacionales en 3D de la anatomía humana, que es útil en el campo de la medicina para facilitar análisis de las estructuras del cuerpo humano.  En este artículo, se realizó una reconstrucción 3D a partir de la segmentación, basada en la diferenciación por área, del órgano(riñón) y estructuras óseas de una serie de imágenes de un TAC abdominal. También, implementamos una interfaz interactiva para la visualización de los planos (frontal, sagital y transversal). La interfaz que muestra los diferentes planos y también carga la reconstrucción 3D que se generó en un proceso aparte, da la opción al usuario de seleccionar cualquier estudio TAC que tenga almacenado en su ordenador. Este procedimiento, según el campo de aplicación, complementa la interacción y análisis de estructuras anatómicas al médico, permite planificar un tratamiento oportuno que ayudará al análisis preoperatorio de patologías complejas y la formulación de estrategias quirúrgicas

    A new integrated methodology for characterizing and assessing suitable areas for viticulture: A case study in Northwest Spain

    Get PDF
    .In 2018, Spain was the third largest producer and the leading exporter of wine in the world. Viticulture is an important economic activity in the Castilla y León region, and is an element capable of halting the flight from the countryside and favouring demographic settlement in rural areas. A new integrated methodology for characterizing and delimitating areas suitable for vineyard cultivation is proposed here. The approach combines traditional climate indices with others used in bioclimatology and with soil variables, and applies various statistical analyses to select the predictors that best characterize the vineyards. These predictors are then integrated in species distribution models and a geographic information system. The methodology was tested in the Denomination of Origin León (hereafter DO León) in northwest Spain. Ten single models using the maximum entropy modelling algorithm were run for each of the six wine-grape varieties. Single-model projections built as a consensus of the ten models into an ensemble-forecasting approach were later used to generate maps of suitable areas for each variety. The results confirm the delimitation of the DO León as a Denomination of Origin. The bioclimatic variables Compensated Thermicity Index and Continentality Index and the soil variables pH, Clay Content, Soil Retention Capacity and Soil Saturation Humidity are defining for all the varieties studied. Garnacha and Mencía were the most different varieties in relation to their bioclimatic and soil requirements. Suitability maps revealed that the DO could be extended into neighbouring areas up to 30 km around it. The proposed methodology is a useful tool for agronomic and oenological management; it allows a more effective selection of sites for new vineyards, improves vineyard management, and can even be used to protect territories with a historical and cultural heritage of grape cultivation, thus favouring demographic settlement in rural areas and avoiding depopulation.S

    Diseño y construcción de un sistema medidor de fuerzas y su aplicación en el diseño de montajes didácticos

    Get PDF
    El objetivo de este Trabajo Fin de Grado es el diseño y construcción de un sistema que permita medir fuerzas de forma sencilla y económica, y aplicarlo a una serie de experiencias didácticas en el laboratorio relacionadas con el equilibrio estático de los cuerpos rígidos. En el Trabajo se han diseñado dos montajes que formarán parte de las sesiones de prácticas para el alumnado del Departamento de Física Aplicada de la E.I.N.A. El primero permite comprobar el valor de las reacciones en los apoyos de una escalera en dos situaciones: sin rozamiento y con rozamiento. El segundo estudia la descomposición de fuerzas bajo la influencia de una carga en una cercha simple. Se trata de una Trabajo transversal a varias áreas de conocimiento, fundamentalmente electrónica (adquisición de datos, uso de convertidores de señal), informática (uso de software y hardware), diseño (concepción y materialización de la idea y planos para mecanización de piezas) y mecánica (realización de estructuras y aplicación de leyes)

    Distraction of cyclists: how does it influence their risky behaviors and traffic crashes?

    Get PDF
    Background. Undisputedly, traffic crashes constitute a public health concern whose impact and importance have been increasing during the past few decades. Specifically, road safety data have systematically shown how cyclists are highly vulnerable to suffering traffic crashes and severe injuries derived from them. Furthermore, although the empirical evidence is still very limited in this regard, in addition to other human factors involved in cycling crashes, distractions while cycling appear to be a major contributor to the road risk of cyclists. Objectives. The main objectives of this study were, first, to explore the prevalence and trends of cycling distractions within an international sample of bike users, and second, to determine the influence of such distractions on road crashes suffered by cyclists, simultaneously considering the explanatory role of risky behaviors (errors and traffic violations) as potentially mediating variables between cycling distractions and traffic crashes. Methods. For this cross-sectional study, we analyzed the data obtained from 1,064 cyclists 61.2% male and 38.8% female from 20 different countries, who answered an on-line questionnaire on cycling-related features, habits, behaviors and accidents. Results. The prevalence of different cycling distractions oscillated between 34.7% and 83.6%. The most common distractions were those related to the behavior of other users, physical elements of the road, weather conditions and phone calls. Age trends and differences were also found, thus establishing a positive association between age and distractibility during cycling. Furthermore, the effect of distractions on traffic crashes of cyclists was significant when tested together with age, risk perception and risky behaviors on the road. Conclusion. The results of this study support the hypotheses that distractions have a major prevalence among bike users, and that they play a significant role in the prediction of the traffic crash rates of cyclists, through the mediation of risky behaviors

    Are Latin American cycling commuters 'at risk'? A comparative study on cycling patterns, behaviors, and crashes with non-commuter cyclists

    Get PDF
    Introduction: As part of the transformation of urban transportation dynamics, commuter cycling has acquired a high relevance as an alternative mode of transport in different countries, and Latin America seems to be one of the main focus of this worldwide 'revolution'. However, the high rates of crashes and injuries suffered by commuters have become a relevant issue in the field of road safety, especially in emerging regions with low cycling tradition, where social and infrastructural gaps may endanger the cyclists' safety. Objectives: This study had two objectives. First, to compare key safe cycling-related variables between cycling commuters and non-commuters; and second, to differentially asses the effect of individual and cycling-related variables on their self-reported crash rates. Method: For this cross-sectional research, the data provided by 577 Latin American urban cyclists from three countries (Argentina, Colombia and Mexico) with a mean age of 32.7 years was used. They answered a questionnaire on cycling habits, risk perception, rule knowledge, cycling behaviors and riding crashes. Results: The outcomes of this study showed that, despite having a higher risk perception, cycling commuters perform deliberate risky cycling behaviors (traffic violations) more frequently, and they suffer more crashes; cycling commuters report higher rates of psychological distress, and a lower degree of rule knowledge and protective behaviors than non-commuters. Furthermore, structural similarities and differences in the explanation of cycling crashes were found across commuters and non-commuters. Conclusion: The results of this study suggest that non-commuters, whose purposes for cycling are more aimed at leisure and occasional trips, perform less risky behaviors but suffer more cycling distractions, whereas commuters are comparatively more exposed to behavioral-based safety risks, and suffer more frequent crashes. Since recent evidence forecasts that urban cycling will keep growing in Latin American cities, it is necessary to implement policies and educational/training improvements that may enhance the safety and health of cyclists in these countries
    corecore