908 resultados para Mesures micro-ondes.


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Regional disparities in unemployment rates are large and persistent. The literature provides evidence of their magnitude and evolution, as well as evidence of the role of certain economic, demographic and environmental factors in explaining the gap between regions of low and high unemployment. Most of these studies, however, adopt an aggregate approach and so do not account for the individual characteristics of the unemployed and employed in each region. This paper, by drawing on micro-data from the Spanish wave of the Labour Force Survey, seeks to remedy this shortcoming by analysing regional differentials in unemployment rates. An appropriate decomposition of the regional gap in the average probability of being unemployed enables us to distinguish between the contribution of differences in the regional distribution of individual characteristics from that attributable to a different impact of these characteristics on the probability of unemployment. Our results suggest that the well-documented disparities in regional unemployment are not just the result of regional heterogeneity in the distribution of individual characteristics. Non-negligible differences in the probability of unemployment remain after controlling for this type of heterogeneity, as a result of differences across regions in the impact of the observed characteristics. Among the factors considered in our analysis, regional differences in the endowment and impact of an individual’s education are shown to play a major role.

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Une première étude menée par les auteures de cet article dans le cadre de l'Unité de médecine des violences du Centre hospitalier universitaire vaudois et de l'Institut universitaire romand de santé au travail avait montré que les conséquences à long terme d'une agression physique au travail pouvaient être sérieuses et le soutien de l'employeur était primordial pour surmonter les conséquences d'un tel événement. Une étude complémentaire, dont les résultats sont présentés ici, avait pour but de formuler des propositions concrètes de mesures de prévention de la violence physique au travail dans le contexte suisse. Les résultats sont présentés dans un «fil rouge» qui se présente sous forme de check-lists de recommandations concrètes. Ce travail s'appuie sur l'analyse et la synthèse d'une abondante documentation, ainsi que sur des entretiens auprès de personnes-ressource et des témoignages de victimes d'agressions physiques au travail. En conclusion, il apparaît que les mesures existantes en Suisse sont encore trop souvent partielles et fragmentées, et se limitent souvent à des offres de formation ou d'information ponctuelles. Alors même que les organisations sont de plus en plus confrontées aux agressions envers le personnel, il y a lieu de les sensibiliser à la nécessité d'instaurer de véritables dispositifs de prévention inscrits dans la durée et s'appuyant sur des modèles éprouvés, opérant aux trois niveaux de prévention primaire, secondaire et tertiaire.

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Diabetic macular edema (DME) is a frequent complication of diabetic retinopathy and may cause severe visual loss. In this article, we examine the pathophysiology of DME and review various treatment options, such as laser photocoagulation, anti-vascular endothelial growth factor (VEGF) receptor antibodies, and steroids including ILUVIEN(®), which is a new sustained-release, non biodegradable, injectable, intravitreal micro-implant containing fluocinolone acetonide. The results of the FAME (Fluocinolone Acetonide in Diabetic Macular Edema) studies, conducted to evaluate the efficacy and safety of ILUVIEN(®) in DME, are discussed.

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L'économie de mouvement en course à pied est un paramètre essentiel pour la performance et de nouvelles méthodes d'entrainement essaient aujourd'hui de le cibler. La mesure de cette économie de course se fait habituellement en laboratoire par la consommation d'oxygène nécessaire au déplacement à une vitesse donnée sous-maximale. La question de cette étude est de voir dans quelle mesure l'oeil averti d'un entraineur en course à pied peut estimer l'économie de course, en comparaison à une mesure objective de la consommation d'oxygène. Au total, 22 coureurs de niveaux différents et 9 entraineurs ont pris part à cette étude. Elle s'est dans un premier temps déroulée avec les coureurs sur le site du Stade de Coubertin à Vidy (VD). Cette étape a permis les enregistrements vidéo et la mesure de leur économie de course respective ainsi que l'établissement des notes d'économies de référence. Dans un second temps, les évaluations par les entraineurs ont été faites en ligne sur la base des vidéos. Les résultats ont été traités de telle manière à obtenir des coefficients (corrélation intraclasse et kappa de Cohen) estimant la concordance des évaluations de chaque entraineur avec les notes de référence. La concordance au sein du groupe d'entraineurs a aussi été évaluée. L'étude présente en conclusion des résultats étonnants, remettant en question la capacité des entraineurs à évaluer l'économie de course de coureurs issus d'un groupe de performances hétérogènes par rapport à des mesures objectives. En revanche, l'étude présente des résultats indiquant une bonne concordance des entraineurs entre eux.

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Peer-reviewed

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Two models of a glass micro-extractor were constructed after modification of a model proposed in the literature. The two models were used for the simultaneous extraction and enrichment of organochlorinated pesticides from aqueous matrixes to an organic solution appropriate for the gas chromatographic analysis of the pesticide. It was established that the performance of one of the modified micro-extractors permits the pre-concentration of the pesticides to a level that allow their quantitation at the trace level with electron capture detection. It is thus concluded that the glass micro-extractor is a suitable tool for the sample preparation step in the gas chromatographic analysis of environmental pollutants of the class of pesticides.

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The technique of solid phase microextraction (SPME) was used for the extraction of halogenated contaminants of water samples from three cities of the State of São Paulo and the extracts were submitted to gas chromatographic analysis with electron capture detection (GC-ECD). In the samples of water collected at the city of São Paulo the detected level of trihalomethanes (THM) expressed as the sum of chloroform, dibromochloromethane and dichlorobromomethane, were higher than the permissible limit established by the Brazilian regulation. In the samples collected at the two other cities the level of any of the three THM remained below the sensitivity of the ECD.

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A procedure for the nitration of phenol in a semi-micro scale, followed by separation of the formed orto- and para-nitrophenol isomers by column chromatography, is described. All the experiment, including determination of the melting point of the isolated products, require a period of 4 hours, and it is suitable for organic chemistry laboratory undergraduate courses.

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The pyrethroids bifenthrin, permethrin, cypermethrin and deltamethrin were extracted by solid phase extraction (SPE) and solid phase microextraction (SPME). The analysis were performed on a gas chromatograph with electron capture detection (GC-ECD). Octadecil Silano-C18, Florisil and Silica stationary phases were studied for SPE. Better results were obtained for Florisil which gave recoveries from 80% to 108%. Pyrethroids extraction by SPME showed a linear response and a detection limit of 10 pg ml-1. Although the data showed that the two extraction methods were able to isolate the pesticide residues from water samples, the best results were obtained by using SPME which is more sensitive, faster, cheeper, being a more useful technique for the analysis of pyrethroids in drinking water.

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A method for determination of lead and cadmium in aqueous samples using solvent microextraction and dithizone as complexing agent with FAAS was developed. Solvent microextraction parameters were optimized. The effect of foreign ions on the extraction yields was studied. The extraction was carried out until the aqueous to organic phase ratio achieved a 250 fold preconcentration of metals. For preconcentration times of 4 min the 3sigma detection limits, relative standard deviations (n=7) and linear calibration ranges were 1.6 mug L-1, 5.8% and 10.0 -- 80.0 mug L-1 for lead and 11.1 ng L-1, 5.9% and 0.3 -- 3.0 mug L-1 for cadmium, respectively. The solvent microextraction procedure presented here was applied to the determination of lead and cadmium in natural waters.

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This Master's thesis deals with a Micro Scale Wind Wind Turbine application. The thesis consists of nine chapters. The first chapter is an introduction to the philosophy of a small scale wind turbine application. The second defines concepts, and lists the requirements. The third presents the whole application for an On-Grid , and for an Off-Grid arrangement, with main concentration on lighting, heating, and energy storage. The fourth deals with the Inverter's technology, which are used for the conversion of the produced power. The fifth chapter presents the available storage technology and it's possibilities. The sixth deals with the system, and the technological means used for the implementation. The seventh presents the PLC device, which was used as the controller for the management of the whole application. The eighth deals with the concept and the control application philosophy that the PLC involves. And the final chapter presents conclusions and ideas for further considerations.

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Este trabajo de fin de grado intenta, mediante el caso real de la implantación de un ERP en una micro PYME, ajustar a la realidad socioeconómica de la gran mayoría de empresas españolas las técnicas de implantación de software y de gestión de proyectos, usando como elemento conductor un ERP de software libre, para conseguir el triple objetivo de mantener los ratios de calidad deseados en cualquier proyecto de ingeniería de software, con unos costes asumibles por una micro PYME y satisfaciendo las necesidades de negocio.

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In this work a micro-heater device to be used as an integral part of the flow analysis manifold is described. The usefulness of the device was demonstrated using it in the development of a multicommutated flow analysis procedure for the spectrophotometric determination of manganese in plant digest. The method was based on the manganese oxidation by periodate in phosphoric acid medium to form the permanganate anion. The reaction development is dependent on the temperature and it was observed that at 25 °C a time interval of ca. 15 min was necessary for the reaction to attain equilibrium. Setting the temperature to 70 ºC, this time interval could be decreased to ca. 30 s. This condition was easily attained employing the proposed micro-heater device coupled to the manifold. The procedure was applied to manganese determination in soybean digests and results compared with those obtained by inductively coupled argon plasma optical emission spectrometry (ICP-OES). No significant difference at 90% confidence level was observed. A linear response for sample concentrations ranging from 5.0 to 30.00 mg L-1 Mn2+; a relative standard deviation of 1.3% (n = 6) for a typical sample containing 6.3 mg L-1 Mn2+; a sampling rate of 22 determinations per hour; a low reagent consumption, of 12.0 mg NaIO4 per determination; and a detection limit of 1.2 mg L-1 were achieved.

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The singular properties of hydrogenated amorphous carbon (a-C:H) thin filmsdeposited by pulsed DC plasma enhanced chemical vapor deposition (PECVD), such as hardness and wear resistance, make it suitable as protective coating with low surface energy for self-assembly applications. In this paper, we designed fluorine-containing a-C:H (a-C:H:F) nanostructured surfaces and we characterized them for self-assembly applications. Sub-micron patterns were generated on silicon through laser lithography while contact angle measurements, nanotribometer, atomic force microscopy (AFM), and scanning electron microscopy (SEM) were used to characterize the surface. a-C:H:F properties on lithographied surfaces such as hydrophobicity and friction were improved with the proper relative quantity of CH4 and CHF3 during deposition, resulting in ultrahydrophobic samples and low friction coefficients. Furthermore, these properties were enhanced along the direction of the lithographypatterns (in-plane anisotropy). Finally, self-assembly properties were tested with silicananoparticles, which were successfully assembled in linear arrays following the generated patterns. Among the main applications, these surfaces could be suitable as particle filter selector and cell colony substrate.

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Normally, the determination of equilibrium constants (k d) in batch experiments uses a high solution to soil ratio, which does not represent field conditions. In this study we present an alternative method to evaluate adsorption constants, using micro-columns of soil at higher soil to solution ratios. The centrifugation force and equilibration time were investigated. The triadimenol distribution along the column profile is controlled by diffusion and equilibration times greater than 24 h are needed to achieve reproducibility. The centrifugation force must be superior to 670 g in order to guarantee enough extraction of the liquid solution from the soil columns.