Influência do uso de combustíveis alternativos na síntese por combustão via microondas para a produção de materiais cerâmicos com estrutura espinélio

The development and study of detectors sensitive to flammable combustible and toxic gases at low cost is a crucial technology challenge to enable marketable versions to the market in general. Solid state sensors are attractive for commercial purposes by the strength and lifetime, because it isn t consumed in the reaction with the gas. In parallel, the use of synthesis techniques more viable for the applicability on an industrial scale are more attractive to produce commercial products. In this context ceramics with spinel structure were obtained by microwave-assisted combustion for application to flammable fuel gas detectors. Additionally, alternatives organic-reducers were employed to study the influence of those in the synthesis process and the differences in performance and properties of the powders obtained. The organic- reducers were characterized by Thermogravimetry (TG) and Derivative Thermogravimetry (DTG). After synthesis, the samples were heat treated and characterized by Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), analysis by specific area by BET Method and Scanning Electron Microscopy (SEM). Quantification of phases and structural parameters were carried through Rietveld method. The methodology was effective to obtain Ni-Mn mixed oxides. The fuels influenced in obtaining spinel phase and morphology of the samples, however samples calcined at 950 °C there is just the spinel phase in the material regardless of the organic-reducer. Therefore, differences in performance are expected in technological applications when sample equal in phase but with different morphologies are tested

Síntese de pigmentos cerâmicos inorgânicos nanométricos e encapsulados com estrutura core-shell pela rota dos precursores poliméricos

The present work has as objective the development of ceramic pigments based in iron oxides and cobalt through the polymeric precursor method, as well as study their characteristics and properties using methods of physical, chemical, morphological and optical characterizations.In this work was used iron nitrate, and cobalt citrate as precursor and nanometer silica as a matrix. The synthesis was based on dissolving the citric acid as complexing agent, addition of metal oxides, such as chromophores ions and polymerization with ethylene glycol. The powder obtained has undergone pre-ignition, breakdown and thermal treatments at different calcination temperatures (700 °C, 800 °C, 900 °C, 1000 °C and 1100 °C). Thermogravimetric analyzes were performed (BT) and Differential Thermal Analysis (DTA), in order to evaluate the term decomposition of samples, beyond characterization by techniques such as BET, which classified as microporous materials samples calcined at 700 ° C, 800 º C and 900 º C and non-porous when annealed at 1000 ° C and 1100 º C, X-ray diffraction (XRD), which identified the formation of two crystalline phases, the Cobalt Ferrite (CoFe2O4) and Cristobalite (SiO2), Scanning Electron Microscopy (SEM) revealed the formation of agglomerates of particles slightly rounded;and Analysis of Colorimetry, temperature of 700 °C, 800 °C and 900 °C showed a brown color and 1000 °C and 1100 °C violet

Efeito de argilas organofílicas na estrutura e propriedades de nanocompósitos de poli(metacrilato de metila)

Nacomposites of polymers and lamellar clayminerals, has generated high scientific and technological interest, for having mechanical properties and gas barriers differentiated of polymers and conventional composites. In this work, it was developed nanocomposites by single screw extruder and injection, utilizing commercial raw material, with the goal to investigate the quality of new developed materials. It was evaluated the influence of the content and the kind of clay in the structure and in the nanocomposites properties. It was used regular and elastomeric poly (methyl methacrylate) (Acrigel LEP 100 and Acrigel ECP800) and six montmorillonites (Cloisite 10A, 11B, 15A, 20A, 25A e 30B) at the concentration of 1% e 3% in weight. The nanocomposites were characterized by X-ray diffraction (XRD), thermal gravimetric analysis (TGA), transmission electron microscopy (TEM), colorimetric, optical transparency, flexural and tensile tests, Rockwell hardness and esclerometry. It was founded that is possible to obtain intercalated and exfoliated nanocomposites PMMA/MMT, and the top results was obtained in the materials with 1%in clay weight organophilizated with 2M2HT (Cloisite 15A and 20A) presented intercalate and hybrid morphology (exfoliated and flocullated). The ones that was produced with organophilizated clay with 2MHTL8 (Cloisite 30B) had excellent visual quality, but the majority presented hybrid morphology. In the materials processed with organophilizated clay with MT2ETOH (Cloisite 30B), there were color change and loss of transparency. It occurs improvement in a few mechanical properties, mainly in the materials produced with PMMA elastomeric (Acrigel ECP800), being more significant, the increase in the resistance to stripping in those nanocomposites

Ecologia trófica em uma taxocenose de anfíbios: estrutura, filogenia e especialização individual

Historically, ever since the pre-Darwinian naturalists interspecific competition was considered the main force responsible for structuring ecological communities. This interpretation lost strength in the late 70s and throughout the 80s giving room for other views, which consider other factors such as predation, parasitism and the phylogenetic inertia more important. Studies on changes in the trophic niche of a species are still uncommon in general and especially in amphibians. Species considered generalist might actually be a group of individual specialists, or individuals that specialize in a particular category of prey during a period of scarcity of resources, thus reducing intraspecific competition. This work studied the community structure of litter amphibians and trophic variation along the dry and rainy seasons in a population of Leptodactylus macrosternum. Sixteen-litter frog species were studied for their diet. Two central assumptions were tested: 1a) if the community is structured in the niche trophic level, and 1b) if there is a significant difference in the use of food resources by different species (i.e. if the community is structured), the observed structure is the result of ecological interactions or just the current phylogenetic inertia of species. Finally, 2) if there is variation in food resource use between seasons for L. macrosternum. The community showed a structure with respect to the use of food resources, and this structure persisted after taking into account the phylogenetic relationships among species. The diet of Leptodactylus macrosternum varied with the seasons, with a significant degree of individual specialization for the dry season. Patterns of a local community are important to understand its dynamics, and this may play a role in larger- scale processes. Therefore, the studies in community ecology are fundamental to understand and eventually restoring degraded areas

Níveis de homocisteína e desempenho cognitivo em uma amostra populacional de idosos da cidade do Natal-RN

The imprecision of the frontier that separates those cognitive deficits inherent to the human physiological aging process from those which represent the early signs of nervous system degenerative pathologies ,very prevalent among the elderly, has brought attention to the need of studies aiming to establish clinical and/or laboratorial criteria to allow this differentiation. Elderly people living in poor and developing countries are frequently exposed to precarious socioeconomic conditions which facilitate the development of an array of pathologies which have metabolic and nutritional dysfunctions as the established or proposed etiological agents. The levels of certain micronutrients, such as the vitamins B12 and B9 (folic acid), and of some intermediary metabolites, such as homocysteine are being thought of as etiological factors and/or as biological markers of a group of alterations which affect the normal functioning of the nervous system with important reflexes upon cognitive performance. This study aims to investigate the influence of homocysteine, B12 vitamin and folic acid levels on the cognitive performance of the low income elderly population. This transversal study took place in Natal, Rio Grande do Norte State, Brazil, and involved 205 dwelling elderly people, users of the Programa de Saúde da Família, a public healthcare program, maintained by the city s health authorities. A multidimensional questionnaire was used to assess the socio-demographic aspects and the overall health and nutrition conditions. The cognitive performance was measured by the use of the Portuguese version of the Mini Mental State Exam (MMSE). The serum levels of homocysteine, B12 vitamin and folic acid were determined by chemiluminescence. The association between the socio-demographic and serum levels of Hcy, B12 vitamin and folic acid was determined by multiple linear regression. Serum levels higher than 13.5 μmol/l, indicative of hyperhomocysteinemia (HHcy), were found on 25.4% of the sample, being more prevalent in men (p<0.05). Deficitary levels of folic acid (<5ng/mol) and of B12 vitamin (<193 pg/ml) were found on 3.9% and 10.2% of the sample respectively. A negative correlation was found between cognitive performance with both age and HHcy and a positive correlation was found between cognitive performance and schooling. The isolated HHcy R2 values were an explanation to only 4% of the variance of the MMSE scores. However, when associated with schooling and age, this model explains about 25% of this association

Prevalência e fatores associados da síndrome de Osgood-Schlatter em uma amostra populacional de adolescentes brasileiros

Osgood-Schlatter (O-S) syndrome, a pathology of the musculoskeletal system, exhibits high incidence in adolescence, a phase of accelerated bone growth. Detection of physiopathological mechanisms that may cause disorders and dysfunctions in bone growth must be taken into account when planning physical activities, in order to promote normal physiological growth patterns. The aim of this epidemiological investigation was to identify and analyze the relationships between sociodemographic, anthropometric and clinical aspects and O-S. A cross-sectional design was used, with a representative sample of 956 subjects: 474 (49.6%) males and 482 (50.4%) females. Age range varied between 12 and 15 years (mean = 13.7±1.04). We used a battery of tests, previously applied in a pilot study, which met the aims of the investigation. Descriptive statistics (frequency, mean and standard deviation) were used and the odds ratio was calculated from bivariate and multivariate logistic regression (p<0.05). A prevalence of 9.8% was found (n = 94 cases): 11% males and 8.3% females. Hierarchized multivariate analysis showed a significant association between regular physical activities (OR= 1.94; CI 95%, 1.22-3.10) and shortening of the rectus femoris muscle (OR= 7.15; CI 95%, 2.86-17.86). The results may serve as a basis for therapeutic and prophylactic measures, in addition to increasing our knowledge of this syndrome in Brazilian adolescents. This investigation used a multidisciplinary approach, involving elements of anatomy, nutrition, physical education and physical therapy to elucidate the object under study related to Osgood-Schlatter syndrome

Rastreamento populacional para Doença de Gaucher em Tabuleiro do Norte-CE

Background. Gaucher Disease (GD) is a hereditary lysosomal storage disorder characterized by the accumulation of glucosylceramide, mainly in the cells of the reticuloendothelial system, due to a deficiency of the enzyme acid β-glucosidase (GBA). Diagnosis is usually based on measurement of GBA activity in peripheral leukocytes. The purpose of this study was to evaluate the ability of screening for GBA and chitotriosidase activity using Dried Blood Spots on Filter Paper (DBS-FP) to identify individuals at high risk for GD in high-risk populations such as that of Tabuleiro do Norte, a small town in Northeastern Brazil. Methods. Between June 1, 2007 and May 31, 2008, 740 consented residents and descendants of traditional families from Tabuleiro do Norte were submitted to screening with DBS-FP. Subjects with GBA activity <2.19 nmol/h/mL were referred to analysis of GBA and chitotriosidase activity in peripheral leukocytes and in plasma, respectively. Subjects at highest risk for GD (GBA activity in peripheral leukocytes <5.6 nmol/h/mg protein) were submitted to molecular analysis to confirm diagnosis. Results. Screening with DBS-FP identified 135 subjects (18.2%) with GBA activity <2.19 nmol/h/mL, 131 of whom remained in the study. In 10 of these (7.6%), GBA activity in leukocytes was 2.6 5.5 nmol/h/mg protein. Subsequent molecular analysis confirmed 6 cases of heterozygosity and 4 normals for GD. Conclusion. DBS-FP assay was shown to be an effective initial GD screening strategy for high-prevalence populations in developing regions. Diagnosis could not be established from GBA activity in leukocytes alone, but required confirmation with molecular analysis

Impacto da atividade física na qualidade de vida em mulheres de meia idade: estudo de base populacional

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Flutuação populacional e distribuição vertical de Brevicoryne brassicae (L.) (Hemiptera: Aphididae) em couve

O conhecimento da dinâmica populacional e da distribuição vertical de insetos pragas em plantas hospedeiras é fundamental para o desenvolvimento de programas de manejo integrado de pragas. No presente trabalho efetuou-se um levantamento populacional de formas ápteras do pulgão Brevicoryne brassicae (L.), visando determinar a época de maior densidade populacional e a distribuição vertical em plantas de couve, (Brassica oleracea L. var. acephala DC.), cultivadas em Jaboticabal, SP. O estudo foi realizado durante as safras de brássicas de 1998 e 1999, efetuando-se correção da acidez do solo por meio de aplicação de calcário apenas no campo utilizado em 1998. A amostragem dos pulgões foi feita visualmente em folhas classificadas em três categorias: apical, mediana e basal. Nas duas safras estudadas, a infestação de B. brassicae na couve atingiu a maior densidade populacional em setembro, diminuindo rapidamente a seguir. Nos dois campos não se observou a mesma distribuição de B. brassicae em folhas apicais, medianas e basais. Os fatores que podem ter contribuído para as diferenças observadas no padrão de distribuição do pulgão devem estar relacionados com a precipitação pluvial e o calcário magnesiano.

Uso sustentável da Copernicia prunifera (Miller) H. E Moore no semiárido potiguar: valorização de saberes e conservação dos recursos genéticos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Avanços e retrocessos na articulação de um pacto territorial: a experiência do PRONAF Infra-Estrutura

Since minetics The economics and political promotion along the necessity of flexibility in states actions admited actors partipction and social controlo on process of construction in local development. The Programa Nacional de Fortalecimento à Agricultura Familiar (PRONAF) by this framework consists suprass the specific points about contry world in order to embrace territorial dimension of development, focalizing actions that estimulate co-operative pratices among local agents. This work proposal intends to identify advances and regression of PRONAF Infra-estrutura (Framework) by one territorial pact organization considering its administration about mechamisms on advantage conmflicts between distinct actor and their ables to atimulates a construction of new relationships between governors and population. Undderstanding PRONAF action like a process that come from its instrumental proportion surpass looking for substantial elements constructionm on intervention of local development considering administration mechamisms in São Paulo do Potengi (RN) city-council-starting by Conselho Municipal de Desenvolvimento Rural as well changes of institutional arrangement with território da Borborema erection. Throngh documental studies, bibliography researches and interviews we indenttfy an articulante power of Territorial pact partnerships like one of these political process and its sector character as their limits

Biologia populacional de Emerita brasiliensis Schmitt (Crustacea, Hippidae) na Praia Vermelha do Norte, Ubatuba (São Paulo, Brasil)

Emerita brasiliensis Schmitt, 1935 is a common mole crab called tatuíra in Brazil, with distribution from Espírito-Santo State (Brazil) to Buenos Aires Province (Argentina). Specimens were collected bimonthly from May/1992 through March/1993 with 4mm siffers mesh, in the intertidal region at Vermelha do Norte Beach, Ubatuba, São Paulo, Brazil. The animals were sexed and measured with a precision caliper of 0.1 mm (Cl = carapace length). Males presented cl amplitude from 3.4-17.3mm (13.2±2.1mm), and females from 13.8-26.3mm (20.5±1.8mm), showing a well-defined sexual dimorfism for this variable. The population presented a smaller incidence of males in relation to females (0.54:1.00), however in May/1992 an inverse pattern occurred (1.84:1.00). Ovigerous females were present in all samples with exception of May and September/1992 with greater frequencies in July/1992 and January/1993. It is probable that female maturity occurs is reached with 17mm CL, the smallest size in wich ovigerous females were found.

As razões da esquerda radical PCB, PSTU e PSOL: estrutura organizativa e objetivos políticos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Efeitos de doses de nitrogênio e potássio e densidade populacional sobre a classificação de bulbos de cebola

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Espaçamento, densidade populacional e adubação nitrogenada na cultura do milho

A distribuição espacial de plantas por área é um recurso para aumentar a produtividade. Para materiais de alta produtividade, são necessárias mais informações quanto à resposta à adubação nitrogenada. Assim, avaliou-se na cultura do milho a influência do espaçamento, da densidade populacional e de doses de nitrogênio no teor de nitrogênio nas folhas, estimativa do teor de clorofila, número de grãos por espiga, massa de 1.000 grãos, produtividade e teor de proteína nos grãos. O trabalho foi instalado no ano agrícola 2000/2001 e constou de tratamentos representados pela combinação de dois espaçamentos entre as linhas (0,80 e 0,60 m) com três densidades populacionais (40, 60 e 80.000 plantas ha-1) e quatro doses de nitrogênio em cobertura (0, 50, 100 e 150 kg ha-1 N). O aumento na doses de N em cobertura promoveram acréscimo no teor de N foliar, na estimativa do teor de clorofila, no número de grãos por espiga, na massa de 1.000 grãos, na produtividade e no teor de proteína nos grãos de milho. A maior produtividade de grãos foi obtida de acordo com as doses crescentes de N em cobertura juntamente com o espaçamento entre as linhas de 0,80 m e 80.000 plantas ha-1.