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Search Results: 1 - 10 of 534171 matches for " Silva A. Ferreira da "
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Ferromagnetism in Dilute Magnetic Semiconductors
R. da Silva Neves,A. Ferreira da Silva,R. Kishore
Physics , 2010,
Abstract: We study the ferromagnetism of Ga1-xMnxAs by using a model Hamiltonian, based on an impurity band and the anti-ferromagnetic exchange interaction between the spins of Mn atoms and the charge carriers in the impurity band. Based on the mean field approach we calculate the spontaneous magnetization as a function of temperature and the ferromagnetic transition temperature as a function of the Mn concentration. The random distribution of Mn impurities is taken into account by Matsubara and Toyozawa theory of impurities in semiconductors. We compare our results with experiments and other theoretical findings.
Desempenho de modelo climático aplicado à precipita??o pluvial do Estado de Pernambuco
Silva, Bernardo B. da;Ferreira, Maria A. F.;Silva, Vicente de P. R. da;Ferreira, Rafael da C.;
Revista Brasileira de Engenharia Agrícola e Ambiental , 2010, DOI: 10.1590/S1415-43662010000400007
Abstract: in this research the performance of a probabilistic climate forecast model applied to seasonal rainfall of pernambuco state was assessed. four rainy seasons (ec) were defined and each one was subpided in two periods - initial (xi) and final (yi) - for three mesorregions of pernambuco state. the methodology proposed consisted in adjusting proportions of zi (ratio of accumulated rainfall of the first period (xi) and the total rainfall of each ec (xi + yi) in the corresponding ec, year by year, over a time series of at least 30 years, to the beta distribution for obtaining the minimum accumulated rainfall expected at 80% probability level for the period yi of ec. the validation of the model was verified with data collected from 1994 to 2002 for each ec. the lilliefors goodness-of-fit test was used to evaluate the adjustment of model for each set of zi values. results showed a good agreement between the empirical distribution and beta model. there was an increasing trend of lesser agreement in the prediction of ymin during dry or rainy years and good agreement in years considered as normal. the performed model showed success in the prognostics of ymin in more than 80% of the studied localities, over the validation period.
Administra??o da dívida pública sob um regime de metas para infla??o: evidências para o caso brasileiro
Mendon?a, Helder Ferreira de;Silva, Rubens Teixeira da;
Economia Aplicada , 2008, DOI: 10.1590/S1413-80502008000400005
Abstract: the use of the interest rate as the main instrument in the search for inflation target and the fact that large part of the brazilian public debt is indexed to this rate implies a reciprocity between the conduction of monetary policy and public debt management. it was observed that the use of the monetary policy focused on a disinflationary process implied a negative effect that cannot be neglect for the fiscal equilibrium. the findings denote that the strategy of increasing the share of prefixed public bonds and indexed to the price index is adequate to avoid deterioration in the public debt/gdp ratio. on the other hand, an increase in the average maturity of public debt still not provoked the expected advantages. a variable that deserves attention is the credibility in the conduction of the monetary policy because it is capable to promote a fall in the public debt and improves the control on inflation.
A qualidade de vida dos pacientes renais cr?nicos em hemodiálise na regi?o de Marília, S?o Paulo
Ferreira, Ricardo Corrêa;Silva Filho, Carlos Rodrigues da;
Jornal Brasileiro de Nefrologia , 2011, DOI: 10.1590/S0101-28002011000200003
Abstract: introduction: hemodialysis is respon>sible for significant alterations in the quality of life of chronic renal patients. objective: to compare the quality of life of patients on hemodialysis without depression (a) and those with some level of depression (b). methods: this was a transversal and descriptive study in which the beck depression inventory (bdi) and the whoqol-bref scale were used. results: the studied sample consisted of 130 patients, 65.15% in a, and 33.84% in b. the highest levels of depression were related to longer periods of treatment. quality of life indexes were better for a, and, as certain domain increased, also were the others. more differences were observed in the psychological (a: 69.40 and b: 49.22) and physical (a: 62.81 and b: 42.19) domains; and the social relations domain had a better average between the populations, as well as a better correlation with the other domains. conclusion: although there was a low prevalence of depression among hemodialysis patients, some investments should be made in the social, psychological and physical support aiming to improve their quality of life.
New record of Haplometroides intercaecalis (Digenea, Plagiorchiidae) infecting a Brazilian snake
Silva, R. J.;Béda, A. F.;Ferreira, V. L.;
Journal of Venomous Animals and Toxins including Tropical Diseases , 2008, DOI: 10.1590/S1678-91992008000100013
Abstract: phalotris matogrossensis (serpentes, colubridae) was reported as a new host for haplometroides intercaecalis (digenea, plagiorchiidae). the host snake was obtained from the municipality of anastácio, state of mato grosso do sul, brazil. one specimen of h. intercaecalis was recovered from the esophagus of the host and identified by the intercecal position of the vitellaria in the pre-acetabular region. this paper describes the second report of the occurrence of this trematode in fossorial snakes of the genus phalotris in the state of mato grosso do sul, brazil.
Catálogo sistemático dos pólens das plantas arbóreas do Brasil Meridional: IV - Thymelaeaceae, Lythraceae, Lecythidaceae, Rhizophoraceae e Combretaceae
Barth, Ortrud Monika;Silva, S. A. Ferreira da;
Memórias do Instituto Oswaldo Cruz , 1965, DOI: 10.1590/S0074-02761965000100017
Abstract: the authors study pollenmorphologicaly species of the present families that occur like trees in the south brazilian forests, except heimia myrtifolia, which is herbaceous. one group is formed, remarked by three simple colpori, which consists of the species buchenavia kleinii, laguncularia racemosa (combretaceae), heimia myrtifolia *lythraceae) and rhizophora mangle (rhizophoraceae). an other group is represented by the pollen grains of combretum fruticosum, terminalia autralis (combretaceae) and lafoensia pacari (lythraceae), because they present pseudocolpi or similar streaks of a thinner sexine. daphnopsis (thymelaeaceae) is pantoporate with 10 - 14 pori and possesses a superficial pattern like croton-type of the euphorbiaceae. cariniana estrellensis (lecythidaceae), with only three colpi, takes also an isolated position. there are relations between the morphology of pollen grains of the above treated families and those from the guttiferales and rosales.
Cuidados paliativos oncológicos: elementos para o debate de diretrizes nesta área
Silva, Ronaldo Corrêa Ferreira da;Hortale, Virginia Alonso;
Cadernos de Saúde Pública , 2006, DOI: 10.1590/S0102-311X2006001000011
Abstract: the aim of this study was to present elements for debating guidelines on palliative care programs for cancer. a literature survey searched various databases (medline, lilacs, and cochrane library), homepages of palliative care organizations, publications by renowned authors in this area, reference textbooks on the subject, relevant articles cited by these books, and the thesis/dissertation database of capes (the brazilian coordinating body for training university level personnel). the data were grouped into four thematic categories: symptomatic palliation, organization of services, psychosocial characteristics, and spiritual characteristics. the article then proceeds to discuss cancer as a public health problem and its impact on individuals, the concept of palliative care and its context in health care, program models and their guidelines, death and dying, and care and caregivers. the study concludes by discussing the challenges for the brazilian national health system in structuring end-of-life programs as a consequence of the population's aging and increasing cancer incidence.
Microestruturas de pelotas feitas com mistura de redutor e finos de minério
Martins, Jader;Ferreira, Cesar Mendon?a;Silva, Neymayer Pereira da;
Rem: Revista Escola de Minas , 2002, DOI: 10.1590/S0370-44672002000300007
Abstract: new processes utilised for the production of ferro primario has been receiving special attention over the last 10 years. this is due to the necessity to use high grade concentrates which can not be utilised straightforward by the steel mills and do not cause the environmetal problems produced by traditional process. the process of direct reduction from green pellets (rdpc) reported in other works is one of those processes in which the problens associated to coking, sinterization and pelletization do not happen. besides, this new process has other advantages such as the possibility to use the flotation concentrates without the necessity to grind it to the same level as it occurs with the conventional pelletization. this work aims to show some characteristics of the microstructures of pellets made out from the of mixture reducing agent and iron ore fines when they are heated under various conditions of time and temperature.
Microestruturas de pelotas feitas com mistura de redutor e finos de minério
Martins Jader,Ferreira Cesar Mendon?a,Silva Neymayer Pereira da
Rem: Revista Escola de Minas , 2002,
Abstract: Na última década, especial aten o tem sido dada para os novos processos de produ o de ferro primário, que, além de aproveitar matérias-primas que n o podem ser utilizadas pelos processos convencionais, n o apresentam os graves problemas ambientais que ocorrem principalmente nas siderúrgicas integradas. O Processo de Redu o Direta a Partir de Pelota Crua (RDPC) já descrito em outros trabalhos, está incluído no rol daqueles processos em que os problemas ambientais que ocorrem nas coquerias, sinteriza es e unidades de pelotiza o convencional, praticamente n o existem. Além disso, apresenta outras vantagens sobre os processos convencionais, particularmente o de utilizar concentrados de minério de ferro, provenientes de usinas de concentra o por flota o, sem que seja necessário moer o minério e a fonte redutora até a granula o fina que se faz necessária no processo convencional de pelotiza o. Esse trabalho visa a apresentar algumas características das microestruturas de pelotas feitas com a mistura de finos de agente redutor e finos de minério depois de serem submetidas a um processo de aquecimento em várias condi es de tempo e temperatura.
Cuidados paliativos oncológicos: elementos para o debate de diretrizes nesta área
Silva Ronaldo Corrêa Ferreira da,Hortale Virginia Alonso
Cadernos de Saúde Pública , 2006,
Abstract: Este artigo tem como objetivo apresentar elementos para o debate de diretrizes em programas de cuidados paliativos no Brasil. Foi construído por meio de levantamento bibliográfico em base de dados (MEDLINE, LILACS e Biblioteca Cochrane), em sítios na Internet de organiza es e institui es interessadas em cuidados paliativos, em textos de autores fundamentais na área, em livros de referência, em obras citadas nas referências destes mesmos livros e no Banco de Teses da CAPES. Os dados foram agrupados em quatro categorias temáticas: controle de sintomas, organiza o de servi os, aspectos psicossociais e espirituais. Com isso, procedeu-se a discuss o do cancer como um problema de saúde pública e seu impacto no indivíduo, o conceito de cuidados paliativos e seu contexto na aten o à saúde, os modelos de programas e suas diretrizes, a morte e o morrer e os cuidados e cuidadores. O artigo termina apontando os desafios do sistema de saúde brasileiro em estruturar programas de cuidados ao final da vida em conseqüência do envelhecimento da popula o e do aumento da incidência do cancer.
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