971 resultados para Íons lantanídeos


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In this paper, we will address together the magnetic and electrical properties of a particular semiconductor, the GaMnAs. The treatment will be done analytically in the first part of the work, according to the computational method for simulation of physical systems through the implementation of the expressions obtained in the first part. All study of magnetic contribution will be made using an interaction Kondo type, using an approach by Green functions. The electrical part, which consists of the Coulomb interactions between carriers and Mn ions, will be treated within the approach of multiple scattering. The implementation of the proposed method will calculate the Green functions converged as multiple scattering solution and use them as a starting point for the calculation of the effective magnetic interactions between Mn ions mediated charge carriers. The concentration parameters were varied for Mn ions and carriers as well. The combination of these two parameters can lead to insulating, metal samples with carriers in Fermi level to low or high mobility. As a result a correlation between the obtained carrier mobility and the strength of magnetic interaction. The greater mobility, the greater the intensity of the interaction.

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Afscheidsrede: Openheid in het onderwijs kent vele verschijningsvormen. In deze rede beperk ik me tot het vergelijken van de openheid van open universiteiten met die van grootscha- lige open online cursussen, beter bekend als MOOC’s. MOOC’s zijn de meeste recente en meest in het oog springende loot aan de boom van openheid in het onderwijs. Na enkele definities van openheid in het onderwijs de revue te laten passeren, bespreek ik kort de ongeveer 40-jarige geschiedenis van openheid zoals open universiteiten die hebben vorm gegeven en de ongeveer 5-jarige geschiedenis van MOOC’s. Dat leidt tot het inzicht dat beide vormen van openheid gestoeld zijn op geheel verschillende uitgangspunten. Waar open universiteiten gebouwd zijn op het fundamentele, door de overheid gegarandeerde recht op onderwijs, komen MOOC’s voort uit marktden- ken; waar open universiteiten aansluiten bij een humanitair waardesysteem, omarmen MOOC’s een utilitair waardesysteem. Hoewel voor beide opvattingen ruimte is en misschien wel moet zijn, huldigen sommigen de opvatting dat MOOC’s ons vigerende onderwijs onvermijdelijk overbodig zal maken. In mijn rede bestrijd ik die opvatting en zal ik ook kort schetsen welke rol onze eigen Open Universiteit in die discussie zou moeten nemen.

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Maakt ICT ons nou knapper of juist dommer? In amper twintig jaar is het maatschappelijk leven voor een groot deel verplaatst naar de virtuele ruimte. Alles en iedereen wordt digitaal met elkaar verbonden. Wat is de invloed van al die nieuwe technologie op ons begrip van de wereld, op ons gedrag, op onze cultuur? Wat betekent het voor het onderwijs? Deze sessie bespreekt de rol van media voor onze cognitieve ontwikkeling. Daartoe worden de ervaringen met oude media zoals geschreven tekst, radio en TV gekoppeld aan de wereld van Twitter, Apple, Facebook en Google, en wordt de blik gericht op wat ons nog te wachten staat.

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Maakt ICT ons nou knapper of juist dommer? In amper twintig jaar is het maatschappelijk leven voor een groot deel verplaatst naar de virtuele ruimte. Alles en iedereen wordt digitaal met elkaar verbonden. Wat is de invloed van al die nieuwe technologie op ons begrip van de wereld, op ons gedrag, op onze cultuur? Wat betekent het voor het onderwijs? Deze sessie bespreekt de rol van media voor onze cognitieve ontwikkeling. Daartoe worden de ervaringen met oude media zoals geschreven tekst, radio en TV gekoppeld aan de wereld van Twitter, Apple, Facebook en Google, en wordt de blik gericht op wat ons nog te wachten staat.

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ALVES, Ana paula Melo. Vermiculitas tratadas quimicamente na obtenção de sólidos microporosos como precursores para híbridos inorgânico-orgânicos com aplicações adsortivas. 2009. 124 f. Tese (Doutorado em Quimica) - Centro de Ciências Exatas e da Natureza, Universidade Federal da Paraíba, João Pessoa, PB, 2009.

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MELO, D. M. A. et al. Synthesis and charactezarion of lanthanum and yttrium doped Fe2O3 pigments. Cerâmica, São Paulo, v. 53, p. 79-82, 2007.

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The theoretical recital of the present study it is initiated of the evidence that the work occupies an important space in the man s life in way that the majority of the people works and passes great part of its time inside organizati ons. However, it is verified that the relation between man and work is becoming increasingly disagreement a time that the employees had started to complain work s routines, stress, not use all their potential and inadequate work s conditions. It can be observed by the way of Dejours (1994) studies. Thus, as contribution for the quality of work life s (QWL) studies the research developed here objectified to characterize the public employees quality of work life at EMATER -RN taking as reference an instrumen t of research synthesized from the typical academic literature of the subject. The synthesis of an ampler instrument is a necessity not taken care to the literature that treats on the subject but already perceived by some studies like Moraes et al (1990); Rodrigues (1989); Siqueira & Coleta (1989); Moraes et al (1992); Carvalho & Souza (2003); El -Aouar & Souza (2003) and Mourão, Kilimnick & Fernandes (2005); Adorno, Marques & Borges (2005) amongst others. These studies point out weak points of the existing models in the QWL s literature, as well as they recommend the elaboration of a model more flexible, that contemplates Brazilian cultural characteristics, and that contemplates the entire variable studied in the main existing models. For reach this objectiv e the adopted methodology was characterized as a case study with collected data in qualitative and quantitative way. Questionnaires and comments had been used as sources of evidences. These evidences had been tabulated through of statistical package SPSS ( Statistical Package for Social Science), in which the main technique of multivariate analysis used were the factorial analysis. As for the gotten results, it was verified the grouping of the quality of work life s indicators in 11 factors which are: Work s execution, Individual accomplishment, Work s equity, Relation individual and organization, Work s organization, Adequacy of the remuneration, Relation between head and subordinate, Effectiveness of the communication and the learning, Relation between work and personal life, Participation and Effectiveness of the work processes. Whatever to the characterization of the EMATER -RN s quality of work life it was clearly that to the measure that the satisfaction s evaluation with the QWL in the organization walks to intrinsic factors for extrinsic factors this level of satisfaction goes diminishing what points to the importance to improve these extrinsic factors in the institution. In summary it is possible to conclude that the organization studied has offered a significant set of referring variable to the quality of work life of the individual

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There appears to be a paradox in crime figures according to two reports issued recently by the Home Office in April 2015. The recent crime figures released by the Office for National Statistics (ONS) show a rise in crime in the UK triggered by a rise in violent crime while the figures released by the the Crime Survey of England and Wales (CSEW) (which is based on interviews with members of the public about their experiences of crime) estimated a 7 per cent fall in overall crime to 6.9 million incidents last year. The CSEW, which questions 35,000 people in England and Wales, estimates that crime is now at its lowest level since the study began in 1981.So why have we seen this apparent discrepancy in figures? In reality the ONS figures reflect new reporting practices by the Police and it stated it could no longer approve figures recorded by the police because they were unreliable, prompting major revisions of how each force handles its figures. The renewed focus on the quality of crime recording is thought to have led to improved compliance with national recording standards, leading to proportionally more crimes reported to the police being recorded by them. Improved compliance with recording standards is thought to have particularly affected the way the police recorded crime categories of violence against the person (up 21%) and public order offences (up 14%). These rises were largely off-set by falls in the number of recorded theft offences (down 5%). In contrast to the CSEW, there was a 2% increase in police recorded crime compared with the previous year, with 3.8 million offences recorded in the year ending December 2014 (see Figure 1)

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A adição de aliltrimetilsilano, promovida por TiCl4, a íons N-aciliminios cíclicos de 5- e 6-membros derivados do ácido (S)-(+)-mandélico, (1R,2S)-trans-2-fenil-1-cicloexanol e (1R,2S,5R)-8-fenilmentol ocorreu com baixas a moderadas razões diastereoisoméricas (1:1-6:1) e forneceu as respectivas amidas e carbamatos em bons rendimentos. A melhor diastereosseleção facial foi observada com o uso de (1R,2S,5R)-8-fenilmentol como auxiliar quiral. As amidas e carbamatos 2-substituídos foram convertidos nos alcalóides (S)- e (R)-propil pirrolidina e coniina com eficiente recuperação dos auxiliares quirais.

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L’insuffisance mitrale (IM) fonctionnelle est une complication fréquente des cardiopathies, causée par la dilatation du ventricule gauche (VG) qui empêche la valve de se fermer. L’insuffisance aortique (IA) est une condition associée à des valves mitrales (VM) inhabituellement grandes, et relativement peu d’IM malgré des VG très dilatés. Cet élargissement de la VM a le potentiel de prévenir l’IM dans les VG dilatés. Les mécanismes sont cependant peu compris : il n’est pas clair s’il s’agit d’une croissance active ou d’un étirement passif des feuillets. Également, le timing de l’adaptation valvulaire n’est pas connu. Notre hypothèse est que l’agrandissement de la valve mitrale en IA est un phénomène actif avec réactivation des mécanismes de croissance embryonnaire. Cent-onze rats ont été divisés en deux groupes : IA (perforation aortique) et contrôle. Les animaux ont été sacrifiés à 48 h, 1 semaine et 3 mois après la création du modèle. Des échocardiographies ont évalué la sévérité de l’IA, la présence d’IM et les dimensions du VG. Les valves ont été prélevées pour analyses microscopiques et moléculaires. La création de l’insuffisance aortique a entrainé une dilatation et une hypertrophie du VG. Malgré cette dilatation rapide du VG, aucun animal n’a développé de l’IM fonctionnelle. À l’échographie, le feuillet antérieur mitral était significativement plus long dans les groupes IA. Par microscopie, les feuillets étaient plus épais dés la première semaine. L’IA était associée à une surexpression de collagène α-SMA (un marqueur de myofibroblastes), TGF-β1 et MMP-2 dans le tissu valvulaire dès la première semaine. Les valves exposées à l’IA étaient également positives pour ces différents facteurs dés les premiers jours. L’agrandissement de la VM est un phénomène actif qui survient rapidement après la création de l’IA, en parallèle de la dilatation du VG. La stimulation de cette croissance dans d’autres pathologies pourrait contribuer à prévenir l’IM fonctionnelle.

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Background: In 2013, the Revised Dietary Goals for Scotland (SDGs) were published to “indicate the direction of travel, and assist policy development to reduce the burden of obesity and diet-related disease in Scotland”. They include recommendations for foods (fruit and vegetables, oily fish and red meat) and nutrients (energy, energy density, total fat, saturated fat, trans fatty acids, sugar, salt and fibre). Progress towards the SDGs is monitored using a combination of surveys, principally the secondary analysis of the Living Costs and Food Survey (LCFS). Objective: To obtain estimates of food consumption and nutrient intake for Scotland using LCFS data from 2001 to 2013. Results: For SDGs measured using LCFS data there was little progress towards meeting the goals between 2001 and 2013. This was apparent even amongst least deprived households. Despite evidence of progress for fruit and vegetables up to 2010, consumption subsequently dropped; and there was no change in oil rich fish consumption. Mean total red meat consumption meets the SDG and a significant reduction was found between 2001 and 2013, which was partly accounted for by a fall in red meat products such as sausages and burgers. Energy density increased significantly over time despite a dip in 2012. Saturated fat, total fat and sugar intakes remained considerably higher than the SDGs. Overall there were small but significant decreases in the percentage of food energy from saturated fat and sugars, although intakes appear to have risen since 2011. There was no change in fibre intake. Conclusion: The results presented support work by Food Standards Scotland and the Scottish Government to facilitate improvements to the diet to help prevent obesity. Whilst some very small improvements were observed however, new approaches are required to encourage the population towards a healthier diet to secure Scotland’s health in the future. Funded by Food Standards Scotland, Project Number FS424018. Data provided by DEFRA, Scottish Neighbourhood Statistics, ONS and the UK Data Archive.