998 resultados para skull base


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Disseny i implementació de la base de dades d'un sistema de recollida de dades d'activitat física provinents de dispositius "portables", a més de les dades de salut dels ciutadans de la Unió Europea.

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Disseny i implementació d'una base de dades relacional per a la gestió d'un videojoc, el qual s'ha d'incorporar a un sistema per obtenir dades d'ús dels usuaris.

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In this paper, an overview about philosophy of science, the concept of "theory" and some characteristics of a"good"theory (1- ordination and explanation of the facts, 2- proposal of problems, and 3- simplicity and funcionality) are initialy introduced. Following, some historical landmarks of acidity and basicity and a summary of the main acid-base theories of the XX century (Arrhenius, solvent systems, protonic, electronic, Lux, Usanovich and ionotropic) are presented. Historical and conceptual relations between these theories are discussed and the three characteristics of a "good" theory are applied. The results showed that the protonic and eletronic theories are the "best". Some discussion of the implications to chemical education are presented too.

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Este proyecto consiste en diseñar e implementar un sistema de información alojado en una base de datos Oracle, con el fin de dar respuesta al proyecto Big Data, cuyo objetivo es cruzar los datos de salud y los datos de actividad física de los ciudadanos europeos.

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Multicomponent ( Al2O3, CaO, SiO2, MgO) calcium aluminate-based glasses containing Nd3+ were prepared in order to evaluate their possibilities as laser host materials. The refractive index, UV-visible-near IR absorption spectrum, IR and visible luminescence spectra, and fluorescence decay time were measured. Judd-Ofelt model was used to obtain experimental intensity parameters ( omega2, omega4 and omega6), emission cross-section, radiative lifetimes, emission branching ratios and quantum efficiency.

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Aquest treball de final de carrera vol donar una solució a un suposat encàrrec de la Unió Europea de construir una base de dades relacional que permeti emmagatzemar dades de l'activitat física dels ciutadans, obtingudes a partir de dispositius wearables, i dades de l'estat de salut i malalties diagnosticades, recollides pels sistemes informàtics dels diferents serveis de salut. Amb totes aquestes dades recopilades la nostra base de dades permetrà, a través d'aplicacions d'alt nivell, extreure informació útil que permeti conèixer l'estat de salut real dels ciutadans i dissenyar actuacions i campanyes que permetin la seva millora.

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A sequential system for fractionation by ultrafiltration (SSFU) equipped with advanced membranes filters (molecular size cut-off: 5, 10, 30, 50 and 100 kDalton) of the polyethersulfone type was developed for analytical fractionation of humic substances (HS) extracted from aquatic systems or soils. The device consists of five membrane filters (Sartocon® Micro) operated by a multi-channel peristaltic pump, enabling an easy handling, working in a closed system and with simple collection of the six obtained fractions (F1>100; F2: 100-50; F3: 50-30; F4:30-10; F5: 10-5 and F6 <5 kDalton). Then, the HS sample (250 mL solution 1.0 mg/mL, pH 5.0 to 6.0) to be fractionated is pumped by pump through the series of membrane filters with a tangential flow of 85 mL/min, initial pressure 0.2 to 0.3 bar and permeation flux through the membranes of 0.8 to 1.4 mL/min. The overall time for fractionation and cleaning of the device is about 10 h and 25 mL of each fraction is obtained.

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Crude extract of Tibouchina granulosa, Rhododendron simsii and Phaseolus vulgaris L. were prepared and used as alternative indicators in quantitative analysis teaching in standardization of NaOH solutions and in the determination of acetic acid contents in vinegar. Effect of using such natural extracts as indicators was very attractive to the students and the quantitative results were compared with conventional indicators with good agreement. Concepts of data statistics can successfully be discussed using the interest revived by the use of natural indicators.

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Recerca centrada en l’anàlisi de característiques concretes de l’educació inclusiva en un entorn d’educació no formal, com és el futbol base. El criteri que s’ha utilitzat per realitzar l’anàlisi són els agrupaments. Des de l’educació inclusiva es promouen els agrupaments heterogenis, una forma d’agrupar a l’alumnat tenint en compte les seves diferències, per tal d’enriquir-se entre tot l’alumnat i treure profit d’elles. A la vegada aquest agrupament es caracteritza per fomentar la igualtat d’oportunitats en l’aprenentatge dels alumnes. En canvi, al futbol base predominen els agrupaments homogenis, distribuint als jugadors segons el seu nivell en diferents equips. A la recerca es fa una comparació entre l’opinió de diferents membres involucrats en el món del futbol base de dues entitats esportives, un club de futbol, on es fan els grups de forma homogènia, i una escola de futbol, on es fan els agrupaments de forma heterogènia. Els resultats mostren que realitzant agrupaments homogenis no s’assegura que tots els jugadors tinguin les mateixes oportunitats d’aprenentatge i que el nivell competencial dels jugadors en edat de formació pot ser un element que fomenti desigualtats en el seu procés d’aprenentatge esportiu.

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El TFC s'ha basat en la creació d'una aplicació basada en tecnologia J2EE que permet obtenir informació bursàtil a través de la font d'informació de Yahoo Finances. La informació obtinguda a través d'aquesta font és de dos tipus: en forma de dades incloses en un arxiu descarregable o en forma de gràfica que el client pot veure directament a l'aplicació. Així doncs, l'aplicació permet mostrar gràfiques de preus d'accions bursàtils i també descarregar-ne arxius amb dades.

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This paper reviews the most important methods used to characterize the porosity of styrene-divinylbenzene resins. Methods such as adsorption of nitrogen for determination of surface area and mercury intrusion porosimetry for characterization of pore size distribution are related.

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The reaction between hydroxy-terminated polybutadiene and isophorone diisocyanate constitutes the base of the curing process of the most composite solid propellant used in the propulsion of solid rocket propellant. In this work, differential scanning calorimetry and viscosity measurements were used to evaluate the effect of the ferric acetylacetonate catalyst concentration on the reaction between HTBR and IPDI. These analyses show one exotherm, which shifts to lower temperatures as the catalyst concentration increases. The viscosity analyses show that the increase of temperature causes, at first, a reduction in the mixture viscosity, reaching a minimum range called gelification region (increasing the crosslinking density).

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Traducción del Anteproyecto de Propuesta Directiva concerniente a la armonización de las reglas de determinación de los beneficios imponibles, de marzo de 1988.

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Today satellites propulsion is based on the use of monopropellant and/or bipropellant chemical systems. The maneuvering of satellite is based on the hydrazine decomposition micropropulsors catalyzed by metallic iridium supported on g-alumina. This reaction is a surface reaction and is strongly exothermic and implies that the operation of the micropropulsor is controlled by the mass and heat diffusions. For this reason and for the fact that the propulsor operation is frequently in pulsed regime, the catalyst should support high pressure and temperature variations within a short time period. The performance and the durability of the commercial catalyst are jeopardized by the low thermal conductivity of the alumina. The low thermal conductivity of the alumina support restricts the heat diffusion and leads to the formation of hot spots on the catalyst surface causing the metal sintering and/or fractures of the support, resulting in loss of the activity and catalyst destruction. This work presents the synthesis and characterization of new carbon composite support for the active element iridium, in substitution of the commercial catalysts alumina based support. These supports are constituted of carbon nanofibers (30 to 40 nm diameter) supported on a macroscopic carbon felt. These materials present high thermal conductivity and mechanical resistance, as well as the easiness to be shaped with different macroscopic shapes. The mechanical stability and the performance of the iridium supported on the carbon composite support, evaluated in a laboratory scale test in hydrazine decomposition reaction, are superior compared to the commercial catalyst.

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This paper describes the drawing, construction and optimization of a device, which can be used to obtain single crystals of different metallic materials with melting point from 550 to 1050 ºC. Components of ease obtaining and of low cost were used. The device was based on the modified Bridgman technique and it was used to obtain single crystals of copper-based alloys. The temperature axial profiles and a difference less then 1% in the temperature between the wall and the center of the ceramic tube in the critical region for obtaining single crystals of good quality indicated that the oven presents a good thermal stability. Single crystals of CuZnAl and CuAlAg alloys of good quality were growth and characterized using optical microscopy and Laüe X-ray back reflection.