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Search Results: 1 - 10 of 71800 matches for " Maria Augusta; Urbano "
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Tumor do estroma gastrointestinal em idade pediátrica
Freire,Paulo; Portela,Francisco; Gra?a,Bruno; Cipriano,Maria Augusta; Urbano,Marta; Furtado,Emanuel; Lapa,Paula; Duque,Gabriela; Andrade,Paulo; Sofia,Carlos;
Jornal Português de Gastrenterologia , 2012,
Abstract: gastrointestinal stromal tumors (gist) are the most frequent mesenchymal tumors in the digestive tract. usually, they develop after the fourth decade of life and are particularly unusual in paediatric age. the authors present the case of a 14-year old female patient admitted for symptomatic microcytic anemia. upper gastrointestinal endoscopy showed a large gastric submucosal tumor. a diagnosis of gist was made by histological and immunohistochemical (c-kit) tests. genetic assessment of c-kit and pdgfra mutations revealed the absence of both (wild-type tumor). the imagiologic staging showed peritumoral adenopathy and hepatic metastization. after surgical resection of the primitive tumor, imatinib therapy was started and later on replaced by sunitinib, due to disease progression. after 18 months of therapy with this drug the disease is stable but without regression. when compared with gist in adults, paediatric gists have multiple specificities. based on the clinical case described below, the authors highlight these specific characteristics and their clinical implications
Envelhecimento térmico do papel isolante de transformadores. Investiga??o experimental. Modelos de degrada??o.
Martins,Maria Augusta G.;
Ciência & Tecnologia dos Materiais , 2010,
Abstract: the processes involved in the thermal ageing of insulating paper used for electrical power transformers, are not very well known, due to the role played by a great number of parameters and their difficult control. to get information for characterization of those processes, accelerated thermal ageing experiments of cellulosic insulating paper, (kraft paper) immersed in insulating mineral oil inhibited (0,3 % dbpc - di-tert-butyl-para-cresol - oxidation inhibitor) and containing 25 mg of bta /kg oil (benzotriazol - bta - copper passivator) were undertaken in sealed glass ampoules, heated in an oven, at temperatures in the range 70 oc - 180 oc. the monitoring of paper degradation was done by the analysis of some gases dissolved in oil such as: hydrogen, hydrocarbons, oxygen, carbon monoxide and carbon dioxide and liquids like: water and furanic compounds and also by the determination of the degree of polymerization of the paper samples, (dp), besides the analysis of furanic compounds absorbed in the paper. new mathematical relationships of furfuraldehyde concentration in oil, versus the corresponding dp of paper, were established in the above mentioned experiments calculated for oil/paper ratios of core and shell transformers and afterwards compared to degradation models, developed by other researchers. finally, the importance and advantages of these degradation models used for assessment of the useful remaining life of insulating paper of transformers, and the limitations of its application to the assessment of the useful remaining life of transformers are also highlighted here.
Regenera??o de óleos isolantes usados.: Solu??o ou problema?
Martins,Maria Augusta G.;
Ciência & Tecnologia dos Materiais , 2007,
Abstract: the disposal of great quantities of degraded insulating oils has become more and more an environmental concern. this situation played an important role in the development of insulating oil reclamation methods, whose application intends to minimize this problem. this paper reviews the most common reclamation methods used for insulating oils, the basic process mechanism, and the main reclamation technologies. furthermore, the advantages, and drawbacks of the ?on-line reclamation? of insulating oil contained in power transformers (oil reclamation treatment while the transformer is energised at rated load) are also discussed here.
Gest?o da vida útil dos transformadores
Martins,Maria Augusta G.;
Ciência & Tecnologia dos Materiais , 2009,
Abstract: nowadays, utilities are facing the problem of a predictable increasing failure rate, as the transformer populations approach their end of life. the management of the transformers useful remaining life is, nowadays, one of the main concerns of utilities. the preventive maintenance is based on some transformer diagnostic techniques and it is an useful tool, to help the transformer life management, that besides technical criteria, are also based on economic and strategic criteria. this paper presents the most suitable criteria used for transformer life management, the most common diagnostic tools used for condition assessment of transformers, and. the maintenance techniques used for the extension of their remaining useful life.
Furfuraldeído: Um indicador prático da degrada??o térmica do papel Kraft de transformadores
Martins,Maria Augusta G.;
Ciência & Tecnologia dos Materiais , 2007,
Abstract: the transformer life expectancy, in terms of aging, is related to the condition of the solid insulation, as this is the major component of a transformer, that once degraded cannot be replaced without dismantling the entire transformer. this is the reason why it is very important to know the degradation of insulating paper, which can be measured by its average viscosimetric degree of polymerization (dp). to analyse paper, we need to take paper samples, from the transformer, but this is not possible without dismantling it. as thermal degradation of paper do generate furanic compounds and the concentration of these products, namely the furfuraldehyde (2fal) in oil, can be easily measured by hplc (high performance liquid chromatography), this is the best alternative method, used nowadays to determine the aging of kraft paper. the mechanisms of cellulose degradation to produce 2fal, the kinetics of this degradation and also the phenomena which affect the quantity of 2fal dissolved in oil, and the factors that influence these phenomena, are the main issues addressed here.
Monitoriza??o da degrada??o térmica do papel isolante usado em transformadores: Papel "Thermally Upgraded" Versus Papel Kraft
Martins,Maria Augusta G.;
Ciência & Tecnologia dos Materiais , 2007,
Abstract: furfuraldheide (2fal) concentration in oil, analysed by high performance liquid chromatography (hplc), has been successfully used, even with some limitations, as a diagnostic tool for the insulating kraft paper thermal degradation monitoring, in transformers. this is not only because 2fal is the furanic compound produced in major quantity, by kraft paper degradation, but also because 2fal has a good solubility and thermal stability in oil. however, 2fal is not a so good indicator of thermally upgraded insulating paper degradation, as it is, for kraft paper degradation. this information is quite important, as the use of this type of paper in transformers is lately spreading out, more and more, mainly in the field of ultra high voltage transformers. the degradation phenomena of thermally upgraded paper "insuldur" are presented here, in order to explain, why 2fal concentration in oil acts as a lower sensivity indicator, of thermally upgraded paper degradation, than of kraft paper degradation. the results of an experimental comparative study of thermal degradation, of these two types of paper, are also discussed here. it is quite probable that another furanic compound, like the furfurilic alchool (2fol) can be used as a better indicator for the thermally upgraded paper degradation. however, more research must be done, in order to confirm this hypothesis.
Multiple use forest management: an alternative to the extinction of the Araucaria Forest? Manejo florestal de uso múltiplo: uma alternativa contra a extin o com Floresta com Araucária?
Maria Augusta Doetzer Rosot
Pesquisa Florestal Brasileira , 2010, DOI: 10.4336/2012.pfb.55.75
Abstract: This paper advocates the adoption of forest management methods that are consistent with the principles of sustainable development and respectful of multiple forest use as a means to efficiently revert the fragmentation process of the Mixed Ombrophylous Forest (FOM) or Araucaria Forest. The problems related to this endangered forest type are discussed within the context of progressive land use changes observed in its region of natural occurrence. Some concepts of forest management are presented, as well as the new approaches related to the paradigm of sustainability and the focus on other benefits provided by the forest, besides wood products solely. It is also discussed the present trend observed in society, which favors preservation policies, and the obstacles for adopting forest management practices in the FOM. The reasons for the inexpressive role played by the forest component in the incomes of small and medium landowners are analyzed and the rural poverty is considered a determinant factor. The management of the Araucaria Forest based on regulation methods is proposed as a means of enhancing forest conditions in what concerns its structure, species composition and reproductive capabilities, besides achieving sustainable yields of timber and non-timber products. The main characteristics of the use of the selection method are described. O artigo defende a ado o do manejo florestal de uso múltiplo como forma eficaz de reverter a tendência de fragmenta o e degrada o da Floresta Ombrófila Mista (FOM) ou Floresta de Araucária, considerada em perigo de extin o pela gradual convers o de uso do solo na sua regi o de ocorrência natural. Apresenta-se a evolu o do conceito de manejo florestal com as mudan as de paradigma observadas na sociedade, como a sustentabilidade e o enfoque sobre múltiplos bens e servi os produzidos pela floresta, além dos madeireiros. S o discutidas as tendências da sociedade no sentido de privilegiar políticas preservacionistas e os entraves à ado o de práticas de manejo florestal na FOM. Na análise das causas da baixa express o do componente florestal nos ingressos da pequena e média propriedade rural, conclui-se que a pobreza é um fator determinante. Prop e-se o manejo da Floresta de Araucária, apoiado em métodos de ordena o florestal, como forma de garantir a melhoria da floresta em termos de estrutura, composi o florística, manuten o da capacidade de reprodu o e perpetua o das espécies, além de ordenar os recursos florestais (madeireiros e n o-madeireiros) de forma a atingir uma produ o com rendimento sustentado. També
Regulatory policies in education: the organization of schooling in cycles in the State of Goiania, Brazil (1998-2008)
Maria Augusta Peixoto Mundim
Práxis Educativa , 2012,
Abstract: The present article analyzes the organization of schooling in cycles in the State of Goiania, Brazil, in the light of the regulation of education policies that took place in the country from the 1990’s onwards. Our theoretical-bibliographical research took advantage of former analysis of the social regulation performed in the fi elds ofEconomy and Political Sociology, using as reference the theoretical-methodological framework developed by Marx and perfected by Gramsci. It is presumed that, in the current scenario, that are new forms of social regulation that, in its developments, have echoed in the regulation of educational policies and that, in a sense, have informed principles for new forms of organization of the school.
Editorial
Maria Augusta Castilho
Intera??es (Campo Grande) , 2007, DOI: 10.1590/s1518-70122007000100001
Abstract:
Marx, marxismos e Servi o Social Marx, Marxisms and Social Work
Maria Augusta Tavares
Revista Katálysis , 2013,
Abstract:
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