995 resultados para 8 Cycles


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Relatório Final de Estágio apresentado à Escola Superior de Dança com vista à obtenção do Grau de Mestre em Ensino de Dança.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Nickel-copper metallic foams were electrodeposited from an acidic electrolyte, using hydrogen bubble evolution as a dynamic template. Their morphology and chemical composition was studied by scanning electron microscopy and related to the deposition parameters (applied current density and deposition time). For high currents densities (above 1 A cm(-2)) the nickel-copper deposits have a three-dimensional foam-like morphology with randomly distributed nearly-circular pores whose walls present an open dendritic structure. The nickel-copper foams are crystalline and composed of pure nickel and a copper-rich phase containing nickel in solid solution. The electrochemical behaviour of the material was studied by cyclic voltammetry and chronopotentiometry (charge-discharge curves) aiming at its application as a positive electrode for supercapacitors. Cyclic voltammograms showed that the Ni-Cu foams have a pseudocapacitive behaviour. The specific capacitance was calculated from charge-discharge data and the best value (105 F g(-1) at 1 mA cm(-2)) was obtained for nickel-copper foams deposited at 1.8 A cm(-2) for 180 s. Cycling stability of these foams was also assessed and they present a 90 % capacitance retention after 10,000 cycles at 10 mA cm(-2).

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The injection process of glass fibres reinforced plastics promotes the moulds surface degradation by erosion. In order to improve its wear resistance, several kinds of PVD thin hard coatings were used. It is well-known that nanostructures present a better compromise between hardness and toughness. Indeed, when the coating is constituted by a large number of ultra-thin different layers, cracks and interface troubles tend to decrease. However, it is not clear that these nanostructures present a better wear behaviour in erosion processes. In order to study its wear behaviour, a sputtered PVD nanostructured TiAlCrSiN coating was used. The substrate and film surfaces topography were analyzed by profilometry and atomic force microscopy techniques. Film adhesion to the substrate was evaluated by scratch tests. The surface hardness was measured with a Vickers micro-hardness tester. The wear resistance was evaluated by micro-abrasion with a rotating ball tribometer tests. Slurry of SiC particles in distilled water was used in order to provoke the surface abrasion. Different duration tests were performed in order to analyze the wear evolution. After these tests, the wear mechanisms developed were analyzed by scanning electron microscopy. Wear craters were measured and the wear rate was calculated and discussed. With the same purpose, coated inserts were mounted in an injection mould working with a 30% glass fibres reinforced polypropylene. After 45 000 cycles no relevant wear was registered.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Para se detectar diferenças imuno-antigênicas entre 8 amostras de P. brasiliensis isoladas de diferentes áreas endêmicas (Botucatu: Pb 1, 2 e 3; São Paulo: Pb: 18, 192 e 265; Venezuela: Pb 9 e 73), esutdaram-se: 1. A reatividade antigênica de cada amostra nas reações de imunofluorescência indireta (II) e de imunodifusão dupla em gel de agar (ID) contra painel de 20 soros controles positivos para paracoccidioidomicose; 2. A capacidade de induzir resposta imune humoral (medida por imunodifusão) e celular (medida pelo teste de coxim plantar) em camundongos imunizados com an-tígenos de cada amostra. Observamos: 1. As amostras Pb 265 e Pb 9 mostraram-se mais reativas na II; 2. Os antígenos das amostras Pb 192 e Pb 73 foram significativamente mais reativas na ID; 3. Estes dados demonstram diferenças de antigenicidade entre estas amostras; 4. A amostra Pb 18 mostrou baixo poder indutor de resposta imune celular e alta capacidade de indução de resposta imune humoral em camundongos imunizados, revelando dissociação de sua imunogenicidade. Estas diferenças podem indicar a existência de cepas distintas do fungo ou refletir modificações do parasita no hospedeiro ou du rante seu cultivo.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Este oitavo volume dos Anais contem as principais publicações dos diversos programas e linhas de investigação da Unidade de Investigação de Educação e Desenvolvimento (UIED) referentes ao ano de 2007. Inicia-se com um conjunto de textos resultantes da mesa-redonda de homenagem à Prof. Doutora Teresa Arnbrósio, fundadora do nosso Centro de Investigação. Esta sessão em Lisboa encerrou o 2I..rvIColóquio da AFIRSE em 17 de Fevereiro de 2007 e foi coordenada pela Prof. Doutora Idália Sá-Chaves. Interligando sisternicamente a vida e a ciência - parafraseando a feliz expressão do Prof. Doutor Hermínio Duarte-Ramos -, os textos escritos por colegas e estudantes que com ela conviveram de perto testemunham a sua profunda influência nas formas de entender a Educação e nos respectivos percursos de vida. A publicação, espelha-se o trabalho das três linhas de investigação da Unidade de Investigação centradas não só na área da Educação e Sociedade, problematizando o conceito de desenvolvimento no mundo actual -com as suas vertentes no âmbito das politicas educativas, da formação ao longo da vida, da relação entre a educação e o desenvolvimento pessoal - mas também na educação em ciência, e na relação da educação e as novas tecnologias. Uma informação complementar actualizada sobre a organização da UIED, bem como dos trabalhos de Teses de Doutoramento e de Mestrado realizados no Departamento de Ciências SociaisAplicadas da Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa com o apoio de projectos de investigação desenvolvidos na Unidade, é inserida neste volume, tal como ocorreu em volumes anteriores.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A evidência da transmissão extraflorestal da leishmaniose cutâneo-mucosa na região do Vale do Ribeira ensejou o presente estudo epidemiológico prospectivo, visando avaliar a atividade enzoótica de L. (V.) braziliensis. A pesquisa paratisológica da infecção natural em pequenos mamíferos e população canina foi complementada com o teste de imunofluorescência indireta (IFI) para cães e captura de flebotomíneos em ambiente florestal e peridomiciliar. A positividade para o teste sorológico e exame parasitológico somente foi observada para cães residentes e com taxas de 5,6 e 2,4%, respectivamente. Entre animais silvestres e sinantrópicos capturados, destacam-se os pertencentes a Oryzomys (Oligoryzomys) e Rattus rattus, ambos assinalados em proporções equivalentes (29,3%), em ambiente peridomiciliar. Foram capturados apenas 166 exemplares femininos de Lutzomyia intermedia, fato atribuído à borrifação das habitações humanas e anexos com DDT. No contexto epidemiológico mais amplo, discute-se a fragilidade do ciclo extraflorestal da L. (V.) braziliensis; o papel do cão e de pequenos mamíferos, como fonte de infecção domiciliar, além de analisar o potencial deles na dispersão do parasita na área estudada.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The iron(III) complexes [H(EtOH)][FeCl2(L)(2)] (1), [H(2)bipy](1/2)[FeCl2(L)(2)].DMF (2) and [FeCl2(L)(2,2'-bipy)] (3) (L = 3-amino-2-pyrazinecarboxylate; H(2)bipy = doubly protonated 4,4'-bipyridine; 2,2'-bipy = 2,2'-bipyridine, DMF = dimethylformamide) have been synthesized and fully characterized by IR, elemental and single-crystal X-ray diffraction analyses, as well as by electrochemical methods. Complexes 1 and 2 have similar mononuclear structures containing different guest molecules (protonated ethanol for 1 and doubly protonated 4,4'-bipyridine for 2) in their lattices, whereas the complex 3 has one 3-amino-2-pyrazinecarboxylate and a 2,2'-bipyridine ligand. They show a high catalytic activity for the low power (10 W) solvent-free microwave assisted peroxidative oxidation of 1-phenylethanol, leading, in the presence of TEMPO, to quantitative yields of acetophenone [TOFs up to 8.1 x 10(3) h(-1), (3)] after 1 h. Moreover, the catalysts are of easy recovery and reused, at least for four consecutive cycles, maintaining 83 % of the initial activity and concomitant rather high selectivity. 3-Amino-2-pyrazinecarboxylic acid is used to synthesize three new iron(III) complexes which act as heterogeneous catalysts for the solvent-free microwave-assisted peroxidative oxidation of 1-phenylethanol.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Para reconhecer a distribuição dos planorbídeos na 8ª Região Administrativa do Estado de São Paulo, 286 lotes de caramujos procedentes dos 85 municípios que a constituem foram examinados e identificados no Laboratório de Malacologia da SUCEN. Biomphalaria straminea, que ocorre em quatro criadouros - um em Altair e três em S. José do Rio Preto, foi a única espécie identificada capaz de vir a comportar-se naturalmente como hospedeira intermediária de S.mansoni. Isto demonstra que são mínimas as probabilidades da esquistossomose vir a instalar-se na área estudada.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

With an example taken from a late-Hauterivian series of the Lusitanian Basin (Portugal), we will demonstrate the sedimentary record of orbital pattern variations and, consequently, climate variations in an inner platform environment with patterns and isolation changes, allows us to establish 4 major orders of periodicity related to orbital components:- The large cycles ob bed thickness variation, constituted by 31-32 beds, recording the 400 ky eccentricity cycle component;- The medium cycles, represented by byndles of 8-9 beds, related to the 100 ky eccentricity cycle component; - The small cycles, of 3-5 beds, recording the 41 ky obliquity components;- The very small cycles, of 2 beds, related to the 22 ky and 26 ky precession components. The mean duration of each bed is around 11.8 ky, a number very close to that of the precession hemi-cycle. Climatic control on qualitative production is confirmed by the close relation between the bed thickness variations, the insolation variability and the variation of micritized elements concentrations.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In this work, we present a teaching-learning sequence on colour intended to a pre-service elementary teacher programme informed by History and Philosophy of Science. Working in a socio-constructivist framework, we made an excursion on the history of colour. Our excursion through history of colour, as well as the reported misconception on colour helps us to inform the constructions of the teaching-learning sequence. We apply a questionnaire both before and after each of the two cycles of action-research in order to assess students’ knowledge evolution on colour and to evaluate our teaching-learning sequence. Finally, we present a discussion on the persistence of deep-rooted alternative conceptions.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Dissertação para obtenção do grau de Doutor em Engenharia Electrotécnica - Energia pela Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In this paper we report a eight-year prospective study designed to further characterize incidence, epidemiology, specific syndromes, treatment and prognosis associated with fungal infections in neutropenic patients. During the study period 30 fungal infections were diagnosed in 30 patients among 313 episodes of fever and neutropenia (10%). There were 15 cases of candidiasis, 5 pulmonary aspergillosis, 3 sinusitis by Aspergillus fumigatus, 5 infections by Fusarium sp., one infection by Trichosporon sp., and one infection due to Rhodotorula rubra. Blood cultures were positive in 18 cases (60%). The predisposing factors for fungal infection in multivariate analysis were the presence of central venous catheter (p<0.001), longer duration of profound (<100/mm³) neutropenia (p<0.001), the use of corticosteroids (p<0.001), gram-positive bacteremia (p=0.002) and younger age (p=0.03). In multivariate analysis only recovery of the neutropenia (p<0.001) was associated with good prognosis whereas the diagnosis of infection by Fusarium sp. (p=0.006) was strongly associated with a poor outcome. The death rate was 43%. There was no statistically significant difference in the death rate between patients who did receive (52%) or did not receive (50%) antifungal treatment. Identifying patients at risk, specific syndromes and prognostic factors may help to reduce the high mortality associated with disseminated fungal infections in neutropenic patients.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In this study we investigated the effect of 8-Bromoguanosine, an immunostimulatory compound, on the cytotoxicity of macrophages against Leishmania amazonensis in an in vitro system. The results showed that macrophages treated with 8-Bromoguanosine before or after infection are capable to reduce parasite load, as monitored by the number of amastigotes per macrophage and the percentage of infected cells (i.e. phagocytic index). Since 8-Bromoguanosine was not directly toxic to the promastigotes, it was concluded that the ribonucleoside induced macrophage activation. Presumably, 8-Bromoguanosine primed macrophages by inducing interferon alpha and beta which ultimately led to L. amazonensis amastigote killing. The results suggest that guanine ribonucleosides may be useful to treat infections with intracellular pathogens.