982 resultados para Llorente, Juan Antonio de


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The design and development of a plastic optical fiber (POF) macrobend temperature sensor is presented. The sensor has a linear response versus temperature at a fixed bend radius, with a sensitivity of 1.92.10(-3) (degrees C)(-1). The sensor system used a dummy fiber-optic sensor for reference purposes having a resolution below 0.3 degrees C. A comprehensive experimental analysis was carried out to provide insight into the effect of different surrounding media on practical macro-bend POF sensor implementation. Experimental results are successfully compared with bend loss calculations.

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Polymer optical fibers (POFs) doped with organic dyes can be used to make efficient lasers and amplifiers due to the high gains achievable in short distances. This paper analyzes the peculiarities of light amplification in POFs through some experimental data and a computational model capable of carrying out both power and spectral analyses. We investigate the emission spectral shifts and widths and on the optimum signal wavelength and pump power as functions of the fiber length, the fiber numerical aperture and the radial distribution of the dopant. Analyses for both step-index and graded-index POFs have been done.

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Background: Patients with chronic obstructive pulmonary disease (COPD) often experience exacerbations of the disease that require hospitalization. Current guidelines offer little guidance for identifying patients whose clinical situation is appropriate for admission to the hospital, and properly developed and validated severity scores for COPD exacerbations are lacking. To address these important gaps in clinical care, we created the IRYSS-COPD Appropriateness Study. Methods/Design: The RAND/UCLA Appropriateness Methodology was used to identify appropriate and inappropriate scenarios for hospital admission for patients experiencing COPD exacerbations. These scenarios were then applied to a prospective cohort of patients attending the emergency departments (ED) of 16 participating hospitals. Information was recorded during the time the patient was evaluated in the ED, at the time a decision was made to admit the patient to the hospital or discharge home, and during follow-up after admission or discharge home. While complete data were generally available at the time of ED admission, data were often missing at the time of decision making. Predefined assumptions were used to impute much of the missing data. Discussion: The IRYSS-COPD Appropriateness Study will validate the appropriateness criteria developed by the RAND/UCLA Appropriateness Methodology and thus better delineate the requirements for admission or discharge of patients experiencing exacerbations of COPD. The study will also provide a better understanding of the determinants of outcomes of COPD exacerbations, and evaluate the equity and variability in access and outcomes in these patients.

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It is well known in the scientific community that some remote sensing instruments assume that sample volumes present homogeneous conditions within a defined meteorological profile. At complex topographic sites and under extreme meteorological conditions, this assumption may be fallible depending on the site, and it is more likely to fail in the lower layers of the atmosphere. This piece of work tests the homogeneity of the wind field over a boundary layer wind profiler radar located in complex terrain on the coast under different meteorological conditions. The results reveal the qualitative importance of being aware of deviations in this homogeneity assumption and evaluate its effect on the final product. Patterns of behavior in data have been identified in order to simplify the analysis of the complex signal registered. The quality information obtained from the homogeneity study under different meteorological conditions provides useful indicators for the best alternatives the system can offer to build wind profiles. Finally, the results are also to be considered in order to integrate them in a quality algorithm implemented at the product level.

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This study investigated the generation of dissolved free amino acids (DFAA) by the bacterivorous flagellate Rhynchomonas nasuta when feeding on abundant prey. Specifically, it examined whether this flagellate protist exhibits a chemosensory response towards those amino acids. The concentrations of glycine and the and D-enantiomers of glutamate, serine, threonine, alanine, and leucine were determined in co-cultures of the flagellate and bacteria. Glycine, L- and D-alanine, and L-serine were found to accumulate under these conditions in amounts that correlated positively with flagellate abundance, suggesting that protists are involved in their generation. Investigations of the chemotactic response of young and old foraging protists to the same amino acids, offered in concentrations similar to those previously generated, showed that glycine elicited the strongest attraction in both age groups. Young protists were strongly attracted to all the assayed amino acids, whereas older protists maintained a high level of attraction only for glycine. These results suggest that glycine generated by protists actively grazing in bacterially enriched patches functions as an infochemical, signaling to foraging protists the presence of available prey in the aquatic environment.

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Although many optical fibre applications are based on their capacity to transmit optical signals with low losses, it can also be desirable for the optical fibre to be strongly affected by a certain physical parameter in the environment. In this way, it can be used as a sensor for this parameter. There are many strong arguments for the use of POFs as sensors. In addition to being easy to handle and low cost, they demonstrate advantages common to all multimode optical fibres. These specifically include flexibility, small size, good electromagnetic compatibility behaviour, and in general, the possibility of measuring any phenomenon without physically interacting with it. In this paper, a sensor based on POF is designed and analysed with the aim of measuring the volume and turbidity of a low viscosity fluid, in this case water, as it passes through a pipe. A comparative study with a commercial sensor is provided to validate the proven flow measurement. Likewise, turbidity is measured using different colour dyes. Finally, this paper will present the most significant results and conclusions from all the tests which are carried out.

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A novel self-referencing fiber optic intensity sensor based on bending losses of a partially polished polymer optical fiber (POF) coupler is presented. The coupling ratio (K) depends on the external liquid in which the sensor is immersed. It is possible to distinguish between different liquids and to detect their presence. Experimental results for the most usual liquids found in industry, like water and oil, are given. K value increases up to 10% from the nominal value depending on the liquid. Sensor temperature dependence has also been studied for a range from 25 degrees C (environmental condition) to 50 degrees C. Any sector requiring liquid level measurements in flammable atmospheres can benefit from this intrinsically safe technology.

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96 p. : il.

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Android gailu eramangarrietan erabiltzeko Babelium Project-en prototipoa.

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Erabiltzaile baten Twitter kontuko iruzkinen babes kopiak eta kudeaketa egiteko aplikazioa.

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[eus] Gradu Amaierako Lan honek Haur Hezkuntzako etapan familia aniztasunari ematen zaion trataera aztertzea du helburu. Horretarako Bilboko Elizbarrutiko ikastetxe zehatz batean kasu ikerketa bat egitea erabaki da. Azterketaren ardatza ikastetxearen izaera konfesionala familia eredu berrien aniztasuna lantzeko zenbateraino traba izan litekeen frogatzea izan da. Ikerketarako erabilitako metodologia kualitatiboa izan da, eztabaida taldea, elkarrizketa sakonak, behaketak eta edukien analisien bidezko teknikak nagusiak izanik. Teknika horien bitartez lortutako informazioaren inguruan zenbait ondorio atera dira eta, azkenik, horiek guztiak kontuan harturik hobekuntzarako proposamena planteatu da.

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[ES]En este documento se tratará de recopilar toda la información y documentación que se ha buscado y desarrollado para la elaboración del proyecto que se está llevando a cabo. El objetivo final del mismo consiste en el análisis y estudio de los canales de propagación en entornos indoor y outdoor y su posterior comercialización en el mercado de las telecomunicaciones. Este documento recoge los aspectos necesarios para finalizar el proyecto con éxito, tales como planificación, alcance, beneficios del proyecto,presupuesto...

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[ES]En este proyecto se presenta un estudio sobre la estimación de la longitud efectiva de lluvia derivada de los escaneos de elevación obtenidos por el radar meteorológico de Kapildui, en Álava. Se estudia la altura y la longitud de la lluvia para distintos eventos: para lluvia estratiforme y para lluvia convectiva. Se analizará la variabilidad espacial y temporal para diferentes ángulos de elevación del radar. Finalmente, se presentará una versión del algoritmo implementado para el cálculo de longitudes efectivas de lluvia y se realizará un estudio estadístico de la variabilidad de ésta para diferentes direcciones y con diferentes eventos de lluvia.