86 resultados para working range


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We study the dynamics of density fluctuations in purely diffusive systems away from equilibrium. Under some conditions the static density correlation function becomes long ranged. We then analyze this behavior in the framework of nonequilibrium fluctuating hydrodynamics.

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We have developed a differential scanning calorimeter capable of working under applied magnetic fields of up to 5 T. The calorimeter is highly sensitive and operates over the temperature range 10¿300 K. It is shown that, after a proper calibration, the system enables determination of the latent heat and entropy changes in first-order solid¿solid phase transitions. The system is particularly useful for investigating materials that exhibit the giant magnetocaloric effect arising from a magnetostructural phase transition. Data for Gd5(Si0.1Ge0.9)4 are presented.

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We report the first example of a transition to long-range magnetic order in a purely dipolarly interacting molecular magnet. For the magnetic cluster compound Mn6O4Br4(Et2dbm)6, the anisotropy experienced by the total spin S=12 of each cluster is so small that spin-lattice relaxation remains fast down to the lowest temperatures, thus enabling dipolar order to occur within experimental times at Tc=0.16 K. In high magnetic fields, the relaxation rate becomes drastically reduced and the interplay between nuclear- and electron-spin lattice relaxation is revealed.

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Aim: The aim of this study was to assess quality of life (QoL) and degree of satisfaction among outpatients subjected to surgical extraction of all four third molars under conscious sedation. A second objective was to describe the evolution of self-reported pain measured in a visual analogue scale (VAS) in the 7 days after extraction. Study design: Fifty patients received a questionnaire assessing social isolation, working isolation, eating and speaking ability, diet modifications, sleep impairment, changes in physical appearance, discomfort at suture removal and overall satisfaction at days 4 and 7 after surgery. Pain was recorded by patients on a 100-mm pain visual analogue scale (VAS) every day after extraction until day 7. Results: Thirty-nine patients fulfilled correctly the questionnaire. Postoperative pain values suffered small fluctuations until day 5 (range: 23 to 33 mm in a 100-mm VAS), when dicreased significantly. A positive association was observed between difficult ranked surgeries and higher postoperative pain levels. The average number of days for which the patient stopped working was 4.9. Conclusion: The removal of all third molars in a single appointment causes an important deterioration of the patient"s QoL during the first postoperative week, especially due to local pain and eating discomfort.

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The study of proteins has been a key element in biomedicine and biotechnology because of their important role in cell functions or enzymatic activity. Cells are the basic unit of living organisms, which are governed by a vast range of chemical reactions. These chemical reactions must be highly regulatedin order to achieve homeostasis. Proteins are polymeric molecules that havetaken on the evolutionary process the role, along with other factors, of controlthese chemical reactions. Learning how proteins interact and control their up anddown regulations can teach us how living cells regulate their functions, as well asthe cause of certain anomalies that occur in different diseases where proteins areinvolved. Mass spectrometry (MS) is an analytical widely used technique to studythe protein content inside the cells as a biomarker point, which describesdysfunctions in diseases and increases knowledge of how proteins are working.All the methodologies involved in these descriptions are integrated in the fieldcalled Proteomics.

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Space competition effects are well-known in many microbiological and ecological systems. Here we analyze such an effectin human populations. The Neolithic transition (change from foraging to farming) was mainly the outcome of a demographic process that spread gradually throughout Europe from the Near East. In Northern Europe, archaeological data show a slowdown on the Neolithic rate of spread that can be related to a high indigenous (Mesolithic) population density hindering the advance as a result of the space competition between the two populations. We measure this slowdown from a database of 902 Early Neolithic sites and develop a time-delayed reaction-diffusion model with space competition between Neolithic and Mesolithic populations, to predict the observed speeds. The comparison of the predicted speed with the observations and with a previous non-delayed model show that both effects, the time delay effect due to the generation lag and the space competition between populations, are crucial in order to understand the observations

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The Biblioteca de Catalunya (BC) was created in 1907 by the Institut d’Estudis Catalans (IEC). In 1914 the Mancomunitat de Catalunya gave the library its condition of cultural and public service, open to researchers and scholars. The library underwent several changes as a consequence of political events, along the most of 20th century. In 1981 it was recognized by law as national library and it recovered its foundational aim of gathering, preserving and disseminating the bibliographical output of Catalonia and the production related with the Catalan linguistic field. As the proud host of ANADP2, the BC wants to show the attendees to the conference how, since 2004, has positioned itself to face the challenge of the new informational and technological paradigm. The library strategy for oncoming years includes giving open and free access online to the digitization of many of his collections through the portals MDC (Digital Memory of Catalonia), ARCA (Old Catalan Serials Archive) and Google Books project; the creation of the Web Archive of Catalonia and, as the last step in the consolidation of its policy, a high-security preserving repository named COFRE, based on the international guidelines and initiatives and the experience of the BC itself.

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Gender inequalities exist in work life, but little is known about their presence in relation to factors examined in occupation health settings. The aim of this study was to identify and summarize the working and employment conditions described as determinants of gender inequalities in occupational health in studies related to occupational health published between 1999 and 2010. A systematic literature review was undertaken of studies available in MEDLINE, EMBASE, Sociological Abstracts, LILACS, EconLit and CINAHL between 1999 and 2010. Epidemiologic studies were selected by applying a set of inclusion criteria to the title, abstract, and complete text. The quality of the studies was also assessed. Selected studies were qualitatively analysed, resulting in a compilation of all differences between women and men in the prevalence of exposure to working and employment conditions and work-related health problems as outcomes. Most of the 30 studies included were conducted in Europe (n=19) and had a cross-sectional design (n=24). The most common topic analysed was related to the exposure to work-related psychosocial hazards (n=8). Employed women had more job insecurity, lower control, worse contractual working conditions and poorer self-perceived physical and mental health than men did. Conversely, employed men had a higher degree of physically demanding work, lower support, higher levels of effort-reward imbalance, higher job status, were more exposed to noise and worked longer hours than women did. This systematic review has identified a set of working and employment conditions as determinants of gender inequalities in occupational health from the occupational health literature. These results may be useful to policy makers seeking to reduce gender inequalities in occupational health, and to researchers wishing to analyse these determinants in greater depth.

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Primer análisis general del tema que ocupa la atención de un Seminario de Investigación "ad hoc" (Facultad de Economía y Empresa, vinculada al "Observatori de aprenentatge i investigació sobre el canvi i el conflicte socials", PID-UB aprobado en junio de 2010, investigadora principal: María Trinidad Bretones) sobre los intentos de cambio de régimen y de democratización de 2009 en Irán y de enero a mayo de 2011 en los países árabes del norte de África. Es la versión inicial y provisional que será ampliada y mejorada sucesivamente por medio de otros working paper.

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En la actualidad, las cooperativas recolectan, seleccionan, tratan y separan la fruta según su calibre (peso, diámetro máximo, medio y/o mínimo) para que esta llegue al consumidor final según la categoría (calibre). Para poder competir en un mercado cada vez más exigente en calidad y precios, se requieren sistemas de clasificación automáticos que nos permitan obtener óptimos resultados con altos niveles de producción y productividad. Para realizar estas tareas existen calibradoras industriales que pesan la fruta mediante células de carga y con el peso obtenido las clasifican asignando las piezas a su salida correspondiente (mesa de confección) a través de un sistema de electroimanes. Desafortunadamente el proceso de calibración de la fruta por peso no es en absoluto fiable ya que en este proceso no se considera el grosor de la piel, contenido de agua, de azúcar u otros factores altamente relevantes que influyen considerablemente en los resultados finales. El objeto de este proyecto es el de evolucionar las existentes calibradoras de fruta instalando un sistema industrial de visión artificial (rápido y robusto) que trabaje en un rango de espectro Infrarrojo (mayor fiabilidad) proporcionando óptimos resultados finales en la clasificación de las frutas, verduras y hortalizas. De este modo, el presente proyecto ofrece la oportunidad de mejorar el rendimiento de la línea de clasificación de frutas, aumentando la velocidad, disminuyendo pérdidas en tiempo y error humano y mejorando indiscutiblemente la calidad del producto final deseada por los consumidores.

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The silicon photomultiplier (SiPM) is a novel detector technology that has undergone a fast development in the last few years, owing to its single-photon resolution and ultra-fast response time. However, the typical high dark count rates of the sensor may prevent the detection of low intensity radiation fluxes. In this article, the time-gated operation with short active periods in the nanosecond range is proposed as a solution to reduce the number of cells fired due to noise and thus increase the dynamic range. The technique is aimed at application fields that function under a trigger command, such as gated fluorescence lifetime imaging microscopy.

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Desde aquel incipiente interés renacentista del siglo XVI hasta la profesionalización de la arqueología en la actualidad, la ingente actividad realizada en Tarragona ha necesitado de formas de registrarla y organizarla, a fin de ser estudiada en el contexto diacrónico general de la ciudad. Esta tarea se ha visto favorecida en el último decenio del siglo pasado por la aparición y adopción de una herramienta informática que no fue diseñada específicamente para la Arqueología. El GIS o SIG, se ha convertido en un instrumento básico e indispensable para cualquier ciudad que tenga un mínimo bagaje patrimonial. Prueba de ello son las publicaciones de Cartas Arqueológicas obtenidas a partir de este software, o sin ir mucho más lejos, los trabajos presentados en este simposio. Presentamos a continuación la experiencia de Tarragona en la creación de un programa, bajo soporte GIS, para la gestión de la actividad arqueológica. Previamente contextualizaremos esta experiencia ya que es justa heredera de iniciativas individuales y de equipos y proyectos previos que trataron, con mucha menor suerte que no éxito, de organizar y poner orden en la maltrecha documentación arqueológica de nuestra ciudad. Describiremos posteriormente las funcionalidades básicas de este programa, su arquitectura y las aplicaciones realizadas en el desarrollo de sendos proyectos de estudio de la ciudad. En este último caso nos centraremos, principalmente, en el proyecto Planimetria Arqueològica de Tàrraco, impulsado por el Museu d’Història del Ayuntamiento de Tarragona y el Institut Català d’Arqueologia Clàssica, y que ha contado con la colaboración de la Generalitat de Catalunya para su edición. Seguidamente veremos como el uso de la información en capas registrada en el GIS combinada con la inclusión de la cartografía histórica de una ciudad permiten el análisis de problemas arqueológicos irresolubles sólo con los datos estrictamente arqueológicos. En este caso se aplicará sobre la validación de la morfología urbana de Tarraco propuesta por Macias (2000a). Por último se hará una reflexión sobre cuales podrían ser las mejoras aplicables sobre el programa, en previsión de futuras revisiones del mismo.

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Annualising work hours (AH) is a means of achievement flexibility in the use of human resources to face the seasonal nature of demand. In Corominas et al. (1) two MILP models are used to solve the problem of planning staff working hours with annual horizon. The costs due to overtime and to the employment of temporary workers are minimised, and the distribution of working time over the course of the year for each worker and the distribution of working time provided by temporary workers are regularised.In the aforementioned paper, the following is assumed: (i) the holiday weeks are fixed a priori and (ii) the workers are from different categories who are able to perform specific type of task have se same efficiency; moreover, the values of the binary variables (and others) in the second model are fixed to those in the first model (thus, in the second model these will intervene as constants and not as variables, resulting in an LP model).In the present paper, these assumptions are relaxed and a more general problem is solved. The computational experiment leads to the conclusion that MILP is a technique suited to dealing with the problem.