23 resultados para 174-1073


Relevância:

10.00% 10.00%

Publicador:

Resumo:

Background: Metabolic syndrome (MS) is a clustering of cardiometabolic risk factors that is considered a predictor of cardiovascular disease, type 2 diabetes and mortality. There is no consistent evidence on whether the MS construct works in the same way in different populations and at different stages in life. Methods: We used confirmatory factor analysis to examine if a single-factor-model including waist circumference, triglycerides/HDL-c, insulin and mean arterial pressure underlies metabolic syndrome from the childhood to adolescence in a 6-years follow-up study in 174 Swedish and 460 Estonian children aged 9 years at baseline. Indeed, we analyze the tracking of a previously validated MS index over this 6-years period. Results: The estimates of goodness-of-fit for the single-factor-model underlying MS were acceptable both in children and adolescents. The construct stability of a new model including the differences from baseline to the end of the follow-up in the components of the proposed model displayed good fit indexes for the change, supporting the hypothesis of a single factor underlying MS component trends. Conclusions: A single-factor-model underlying MS is stable across the puberty in both Estonian and Swedish young people. The MS index tracks acceptably from childhood to adolescence.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

[EN] Progress in methodology in specific fields is usually very closely linked to the technological progress in other areas of knowledge. This justifies the fact that lexicographical techniques have had to wait for the arrival of the IT era of the last decades of the 20th century in order to be able to create specialised electronic dictionaries which can house and systemise enormous amounts of information which can later be dealt with quickly and efficiently. This study proposes a practical-methodological model which aims to solve the grammatical treatment of adverbs in Ancient Latin. We have suggested a list of 5 types, in a decreasing order from a greater to lesser degree of specialisation; technical (T), semi-technical (S-T), instrumental-valued (I-V), instrumental- descriptive (I-D), instrumental-expository (I-E).

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Anejos de Veleia, Series Minor, 26. Editado por Vitalino Valcárcel.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

La situación del entorno actual, marcado por el efecto de la globalización, conduce a buscar nuevos enfoques organizacionales para ofrecer soluciones prácticas a la creciente dinamización del mercado. Clientes, proveedores, subcontratistas, competidores, centros de investigación, universidades… tienden a interrelacionarse configurando el concepto de “empresa extendida”: red de nodos ágiles, flexibles, con conexiones mundiales y con capacidad de reconfiguración permanente, características vitales para mantenerse competitivo. En este artículo se ha realizado una labor de estudio y análisis de teorías organizacionales consideradas seminales y se ha evaluado su idoneidad en el contexto competitivo actual. El resultado ha sido el diseño de un modelo de gestión basado en un enfoque proactivo que se sustenta en la gestión del conocimiento organizacional y que aboga por valores como el desequilibrio constante, la relación con otras organizaciones buscando efectos sinérgicos y la compartición del saber, entre otros.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Este artículo se ha realizado en el marco de los Proyectos de Investigación titulados “Los sistemas integrados de gestión (SIG) en las empresas españolas” (SEC2006-06682/ECON) financiado por el Ministerio de Educación y Ciencia dentro de la convocatoria de ayuda a proyectos de I+D y “Análisis de la implantación de los Sistemas de Gestión Medioambiental en las empresas de la CAPV: generación de propuestas innovadoras para su integración organizativa”, financiado por la UPV-EHU en su convocatoria general de Proyectos de Investigación de 2006.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Radar services are occasionally affected by wind farms. This paper presents a comprehensive description of the effects that a wind farm may cause on the different radar services, and it compiles a review of the recent research results regarding the mitigation techniques to minimize this impact. Mitigation techniques to be applied at the wind farm and on the radar systems are described. The development of thorough impact studies before the wind farm is installed is presented as the best way to analyze in advance the potential for interference, and subsequently identify the possible solutions to allow the coexistence of wind farms and radar services.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Low Voltage (LV) electricity distribution grid operations can be improved through a combination of new smart metering systems' capabilities based on real time Power Line Communications (PLC) and LV grid topology mapping. This paper presents two novel contributions. The first one is a new methodology developed for smart metering PLC network monitoring and analysis. It can be used to obtain relevant information from the grid, thus adding value to existing smart metering deployments and facilitating utility operational activities. A second contribution describes grid conditioning used to obtain LV feeder and phase identification of all connected smart electric meters. Real time availability of such information may help utilities with grid planning, fault location and a more accurate point of supply management.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The efficiency of the wind power conversions systems can be greatly improved using an appropriate control algorithm. In this work, a sliding mode control for variable speed wind turbine that incorporates a doubly fed induction generator is described. The electrical system incorporates a wound rotor induction machine with back-to-back three phase power converter bridges between its rotor and the grid. In the presented design the so-called vector control theory is applied, in order to simplify the electrical equations. The proposed control scheme uses stator flux-oriented vector control for the rotor side converter bridge control and grid voltage vector control for the grid side converter bridge control. The stability analysis of the proposed sliding mode controller under disturbances and parameter uncertainties is provided using the Lyapunov stability theory. Finally simulated results show, on the one hand, that the proposed controller provides high-performance dynamic characteristics, and on the other hand, that this scheme is robust with respect to the uncertainties that usually appear in the real systems.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This paper presents the construction, mathematical modeling and testing of a scaled universal hydraulic Power Take-Off (PTO) device for Wave Energy Converters (WECs). A specific prototype and test bench were designed and built to carry out the tests. The results obtained from these tests were used to adjust an in-house mathematical model. The PTO was initially designed to be coupled to a scaled wave energy capture device with a low speed and high torque oscillating motion and high power fluctuations. Any Energy Capture Device (ECD) that fulfils these requirements can be coupled to this PTO, provided that its scale is adequately defined depending on the rated power of the full scale prototype. The initial calibration included estimation of the pressure drops in the different components, the pressurization time of the oil inside the hydraulic cylinders and the volumetric efficiency of the complete circuit. Since the overall efficiency measured during the tests ranged from 0.69 to 0.8 and the dynamic performance of the PTO was satisfactory, the results are really promising and it is believed that this solution might prove effective in real devices.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Transmission investments are currently needed to meet an increasing electricity demand, to address security of supply concerns, and to reach carbon-emissions targets. A key issue when assessing the benefits from an expanded grid concerns the valuation of the uncertain cash flows that result from the expansion. We propose a valuation model that accommodates both physical and economic uncertainties following the Real Options approach. It combines optimization techniques with Monte Carlo simulation. We illustrate the use of our model in a simplified, two-node grid and assess the decision whether to invest or not in a particular upgrade. The generation mix includes coal-and natural gas-fired stations that operate under carbon constraints. The underlying parameters are estimated from observed market data.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This paper deals with the economics of gasification facilities in general and IGCC power plants in particular. Regarding the prospects of these systems, passing the technological test is one thing, passing the economic test can be quite another. In this respect, traditional valuations assume constant input and/or output prices. Since this is hardly realistic, we allow for uncertainty in prices. We naturally look at the markets where many of the products involved are regularly traded. Futures markets on commodities are particularly useful for valuing uncertain future cash flows. Thus, revenues and variable costs can be assessed by means of sound financial concepts and actual market data. On the other hand, these complex systems provide a number of flexibility options (e.g., to choose among several inputs, outputs, modes of operation, etc.). Typically, flexibility contributes significantly to the overall value of real assets. Indeed, maximization of the asset value requires the optimal exercise of any flexibility option available. Yet the economic value of flexibility is elusive, the more so under (price) uncertainty. And the right choice of input fuels and/or output products is a main concern for the facility managers. As a particular application, we deal with the valuation of input flexibility. We follow the Real Options approach. In addition to economic variables, we also address technical and environmental issues such as energy efficiency, utility performance characteristics and emissions (note that carbon constraints are looming). Lastly, a brief introduction to some stochastic processes suitable for valuation purposes is provided.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

174 p.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

[ES]Esta obra recoge las comunicaciones seleccionadas para el 6º Congreso Europeo sobre Eficiencia Energética y Sostenibilidad en Arquitectura, organizado por el grupo de investigación Calidad de Vida en Arquitectura de la Universidad del País Vasco/Euskal Herriko Unibertsitatea. El congreso, que se celebra en el marco de los XXXIV Cursos de Verano de la UPV/EHU, aborda en esta cuarta edición el tema “Ciudades en riesgo: resiliencia y redundancia”. Alrededor de este tema general se desarrollan cinco ponencias magistrales, a cargo de Margaretha Breil (Centro Euro-Mediterráneo para el Cambio Climático), Cristina Garzillo Leemhuis (ICLEI), Ignasi Fontanals (OptiCits), Juan Carlos Barrios Montenegro (Global Action Plan) y Manuel Valdés López (Ajuntament de Barcelona). Además, 24 comunicaciones seleccionadas por el comité científico presentarán trabajos de investigaciones actuales en las sesiones orales y póster. Es objetivo paralelo del congreso es fortalecer las líneas de investigación en eficiencia energética y sostenibilidad de los grupos de investigación y formación de la UPV/ EHU comprometidos con esta propuesta, con objeto de colaborar en el reforzamiento de la I D i en su ámbito de conocimiento y apoyar la apuesta específica de los Gobiernos Central y Vasco, así como de otras instituciones nacionales e internacionales respecto a las actividades de I D i en las materias relacionadas con el cambio climático, la eficiencia energética y la sostenibilidad ambiental [ENG] This work contains the selected abstracts of the 6th European Conference on Energy Efficiency and Sustainability in Architecture and Planning, organized by the research group Quality of life in Architecture of the University of the Basque Country. The conference is part of the XXXIV Summer Courses of the UPV/EHU and deals, in its fourth edition, with the topic “Cities at risk: resilience and redundancy”. Around this general theme there are five invited speakers: Margaretha Breil (Euro-Mediterranean Centre for Climate Change), Cristina Garzillo Leemhuis (ICLEI), Ignasi Fontanals (OptiCits), Juan Carlos Barrios Montenegro (Global Action Plan) y Manuel Valdés López (Barcelona City Council). 24 abstracts additional have been selected by the scientific committee that offer actual research works in presentations and posters. The purpose of the conferences is to strengthen the investigation lines in energy efficiency and sustainability of the research and education groups of the University of the Basque Country (UPV/EHU) involved, with the purpose of collaborating in the reinforcement of the I D i in its field of knowledge, and support the specific projects of the Central and Basque Governments, as well as other national and international institutions related to the I Di activities in similar fields of climate change, energy efficiency and environmental sustainability.