979 resultados para computer assisted emission tomography


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Peer-reviewed

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En este trabajo se pretende, por una parte, analizar cuáles son los métodos y programas existentes que se utilizan en la enseñanza de la entonación asistida por ordenador. Por otra parte, se pretende proporcionar algunas ideas para la aplicación del soporte visual en la enseñanza de la entonación

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Obesity has become the leading cause of many chronic diseases, such as type 2 diabetes and cardiovascular diseases. The prevalence of obesity is high in developed countries and it is also a major cause of the use of health services. Ectopic fat accumulation in organs may lead to metabolic disturbances, such as insulin resistance.Weight loss with very-low-energy diet is known to be safe and efficient. Weight loss improves whole body insulin sensitivity, but its effects on tissue and organ level in vivo are not well known. The aims of the studies were to investigate possible changes of weight loss in glucose and fatty acid uptake and perfusion and fat distribution at tissue and organ level using positron emission tomography and magnetic resonance imaging and spectroscopy in 34 healthy obese subjects. The results showed that whole-body insulin sensitivity increased after weight loss with very-low-energy diet and this is associated with improved skeletal muscle insulin-stimulated glucose uptake, but not with adipose tissue, liver or heart glucose uptake. Liver insulin resistance decreased after weight loss. Liver and heart free fatty acid uptakes decreased concomitantly with liver and heart triglyceride content. Adipose tissue and myocardial perfusion decreased. In conclusion, enhanced skeletal muscle glucose uptake leads to increase in whole-body insulin sensitivity when glucose uptake is preserved in other organs studied. These findings suggest that lipid accumulation found in the liver and the heart in obese subjects without co-morbidies is in part reversible by reduced free fatty acid uptake after weight loss. Reduced lipid accumulation in organs may improve metabolic disturbances, e.g. decrease liver insulin resistance. Keywords: Obesity, weight loss, very-low-energy diet, adipose tissue metabolism, liver metabolism, heart metabolism, positron emission tomography

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We live in an era of profound changes in university education. The implementation of Bologna plan has led us to raise new teaching methodologies, to review the role of the student, competency assessment, the incorporation of ICT. Unthinkable acts, one or two decade ago. The TIC concept is very broad and is attributed to the media, processes and content usage. Inside the supports and platforms, we stress tools that allow automatic correction of exercises, because they are instruments of great educational value because instantly they assess students and provide instant feedback about the knowledge that they have either as message support or note. If the power of these tools, we add the Internet, using e-learning environment, the results allow us to work, edit, evaluate, resolve doubts, and so on, anywhere, anytime. We present part of a platform and the results of its use in the field of health sciences

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Across Latin America 420 indigenous languages are spoken. Spanish is considered a second language in indigenous communities and is progressively introduced in education. However, most of the tools to support teaching processes of a second language have been developed for the most common languages such as English, French, German, Italian, etc. As a result, only a small amount of learning objects and authoring tools have been developed for indigenous people considering the specific needs of their population. This paper introduces Multilingual–Tiny as a web authoring tool to support the virtual experience of indigenous students and teachers when they are creating learning objects in indigenous languages or in Spanish language, in particular, when they have to deal with the grammatical structures of Spanish. Multilingual–Tiny has a module based on the Case-based Reasoning technique to provide recommendations in real time when teachers and students write texts in Spanish. An experiment was performed in order to compare some local similarity functions to retrieve cases from the case library taking into account the grammatical structures. As a result we found the similarity function with the best performance

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El objeto de esta comunicación es presentar un estudio exploratorio sobre las funciones y tipologías de metáfora estructurales presentes en productos de e-learning, para estudiar con más detalle dos ejemplos: Geolearning y Activewolds. Estos servirán para realizar un ejercicio de identificación de los elementos audiovisuales presentes en la interface, el tratamiento de las dimensiones espacio y tiempo; el uso de 'avatares' y de las posibilidades de navegación e interacción dentro de los dos sistemas. La teoría de la muldimodalidad (Kress i van Leeuwen) es el marco teórico que conduce la reflexión sobre la representación, orientación y organización de la comunicación. Desde la misma perspectiva teórica, el trabajo de Burn y Parker nos indica pautas metodológicas para el análisis de los productos

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La interactividad describe la relación de comunicación entre un usuario/actor y un sistema (informático, vídeo u otro). El grado de interactividad del producto viene definido por la existencia de recursos que permiten que el usuario establezca un proceso de actuación participativa-comunicativa con los materiales. En opinión de la autora, resulta imprescindible que las informaciones que se canalicen a través de los recursos multimedia hayan sido fruto de un análisis exhaustivo de los posibles errores de interpretación a losque podrían dar lugar al ser utilizados por los destinatarios. Al mismo tiempo, se hace necesaria una preparación de los usuarios que les capacite para ser capaces de recibir, interpretar y valorar este tipo de mensajes, ayudándoles a tomar conciencia del riesgo de falta de comprensión que alberga este nuevo mecanismo o sistema de comunicación. De este modo, se evitarían los aprendizajes parciales y el contenido asimilado sea incompleto o resulte erróneo

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Positron emission tomography (PET) studies on healthy individuals have revealed a marked interindividual variability in striatal dopamine D2 receptor density that can be partly accounted for by genetic factors. The examination of the extrastriatal lowdensity D2 receptor populations has been impeded by the lack of suitable tracers. However, the quantification of these D2 receptor populations is now feasible with recently developed PET radioligands. The objective of this thesis was to study brain neurobiological correlates of common functional genetic variants residing in candidate genes relevant for D2 receptor functioning. For this purpose, healthy subjects were studied with PET imaging using [11C]raclopride and [11C]FLB457 as radioligands. The candidate genes examined in this work were the human D2 receptor gene (DRD2) and the catechol-Omethyltransferase gene (COMT). The region-specific genotypic influences were explored by comparing D2 receptor binding properties in the striatum, the cortex and the thalamus. As an additional study objective, the relationship between cortical D2 receptor density and a cognitive phenotype i.e. verbal memory and learning was assessed. The main finding of this study was that DRD2 C957T genotype altered markedly D2 receptor density in the cortex and the thalamus whereas in the striatum the C957T genotype affected D2 receptor affinity, but not density. Furthermore, the A1 allele of the DRD2-related TaqIA polymorphism showed increased cortical and thalamic D2 receptor density, but had the opposite effect on striatal D2 receptor density. The DRD2 –141C Ins/Del or the COMT Val158Met genotypes did not change D2 receptor binding properties. Finally, unlike previously reported, cortical D2 receptor density did not show any significant correlation with verbal memory function. The results of this study suggest that the C957T and the TaqIA genotypes have region-specific neurobiological correlates in brain dopamine D2 receptor availability in vivo. The biological mechanisms underlying these findings are unclear, but they may be related to the region-specific regulation of dopamine neurotranssion, gene/receptor expression and epigenesis. These findings contribute to the understanding of the genetic regulation of dopamine and D2 receptor-related brain functions in vivo in man. In addition, the results provide potentially useful endophenotypes for genetic research on psychiatric and neurological disorders.

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Atherosclerosis is a vascular inflammatory disease causing coronary artery disease, myocardial infarct and stroke, the leading causes of death in Finland and in many other countries. The development of atherosclerotic plaques starts already in childhood and is an ongoing process throughout life. Rupture of a plaque and the following occlusion of the vessel is the main reason for myocardial infarct and stroke, but despite extensive research, the prediction of rupture remains a major clinical problem. Inflammation is considered a key factor in the vulnerability of plaques to rupture. Measuring the inflammation in plaques non-invasively is one potential approach for identification of vulnerable plaques. The aim of this study was to evaluate tracers for positron emission tomography (PET) imaging of vascular inflammation. The studies were performed with a mouse model of atherosclerosis by using ex vivo biodistribution, autoradiography and in vivo PET and computed tomography (CT). Several tracers for inflammation activity were tested and compared with the morphology of the plaques. Inflammation in the atherosclerotic plaques was evaluated as expression of active macrophages. Systematic analysis revealed that the uptake of 18F-FDG and 11C-choline, tracers for metabolic activity in inflammatory cells, was more prominent in the atherosclerotic plaques than in the surrounding healthy vessel wall. The tracer for αvβ3 integrin, 18Fgalacto- RGD, was also found to have high potential for imaging inflammation in the plaques. While 11C-PK11195, a tracer targeted to receptors in active macrophages, was shown to accumulate in active plaques, the target-to-background ratio was not found to be ideal for in vivo imaging purposes. In conclusion, tracers for the imaging of inflammation in atherosclerotic plaques can be tested in experimental pre-clinical settings to select potential imaging agents for further clinical testing. 18F-FDG, 18F-galacto-RGD and 11C-choline choline have good properties, and further studies to clarify their applicability for atherosclerosis imaging in humans are warranted.

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Els ordinadors s’aniran fent més potents i cada vegada n’hi haurà més a les escoles. La seva utilització serà més senzilla i, per tant, resultarà més fàcil adaptar-los a les necessitats de l’aula. També seran molt útils per atendre la diversitat escolar, ja que l’ordinador permet que cada estudiant pugui progressar al seu ritme. Finalment, l’aparició d’Internet dóna moltes noves possibilitats pedagògiques i, en un futur proper, el fet d’establir comunicacions entre infants de diferents escoles podrà ser una activitat habitual de la majoria de centres

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Actualmente las universidades están inmersas en lo que se conoce como el proceso de «convergencia europea» y que llevará al Espacio Europeo de Educación Superior (EEES). El objetivo es dotar a Europa de un sistema universitario homogéneo, compatible y flexible que permita a los estudiantes y titulados universitarios europeos una mayor movilidad, así como ofrecer al sistema universitario europeo unos niveles de transparencia y calidad, mediante sistemas de evaluación, que le hagan atractivo y competitivo en el ámbito internacional dentro del actual proceso de globalización. En este artículo, interesa centrar la reflexión en dos de las modalidades de la educación a distancia que asumirán importancia en ese cambio universitario: el e-learning y el b-learning, que consisten básicamente en la virtualización de los procesos de aprendizaje a través del uso de equipos informáticos. Para ello se ha realizado una investigación cualitativa con metodología de estudio de casos. De entre los resultados se destaca el uso de las TIC por parte del profesorado para conseguir un mejor aprendizaje en los estudiantes, de igual forma un porcentaje importante de los profesores 78% utiliza alguna plataforma virtual como apoyo a la docencia. Como conclusión se resalta que las políticas de formación deberían fortalecer las competencias del profesorado universitario en el uso de dispositivos telemáticos, recursos e instrumentos relacionados con el aprendizaje semipresencial y virtual.