441 resultados para estrutura e ultraestrutura glomerular
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Tanta a fragmentação com a defaunação tem afetado uma guilda de dispersores não aleatória, grandes aves e mamíferos são os primeiros a desaparecerem. A extinção local de grandes frugívoros deve afetar a estrutura espacial e demográfica de muitas espécies de plantas que possuem frutos carnosos, porém a maioria dos estudos tem enfocado em espécies com poucos dispersores. Nós estudamos as possíveis conseqüências da extinção de grandes frugívoros sobre a distribuição espacial e genética de uma palmeira tropical, o palmito juçara (Euterpe edulis), que possui uma alta diversidade de dispersores de sementes. Utilizando marcadores microssatélites e analisando dados através do grau de parentesco e autocorrelação espacial, observamos que a falta dos grandes dispersores nesta área pode estar limitando a dispersão de E. edulis, acarretando na agregação de indivíduos, alta porcentagem de indivíduos aparentados, possível ocorrência de endocruzamento na população e uma possível estruturação genética espacial até a distância de 10-12 metros. Além disso, o padrão de distribuição espacial observado nas plântulas dentro de uma subparcela pode estar refletindo o padrão de deposição de sementes realizado pelos Turdus spp., o qual regurgita sementes uma a uma; assim, a dispersão esparsa realizada por esses animais pode estar diminuindo a probabilidade de sementes vindas de um mesmo adulto se estabeleçam num mesmo m2. No entanto, é necessário que estudos similares sejam realizados em áreas onde há a ocorrência em altas densidades de outros dispersores a fim de comprovar que a distribuição do E. edulis, encontrada nesta população, não será encontrada em áreas onde estes animais estão presente.
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Este trabalho tem como objetivo demonstrar como o Nordeste se configura como fator dinâmico no processo de desenvolvimento do sistema capitalista brasileiro.Será analisado o significado do retrocesso econômico que a região sofreu, e como isso levou o Nordeste a se tornar um fornecedor de mão-de-obra e de capital para a região centro-sul, pólo dinâmico da economia. Implica também em ver o processo de industrialização do Brasil visando à produção e a acumulação e não o consumo interno, assim o Nordeste não representa um potencial a ser trabalhado. Necessita-se então caracterizar o tipo de dinâmica existente ente a estrutura agrária nordestina e o processo de desenvolvimento industrial brasileiro, que levou o nordeste a participar ativamente desse processo
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The climate is one of the main elements of the natural environment that governs the life of man. Specific conditions of temperature, humidity, light, wind and precipitation have direct influence on physiological conditions that man needs to survive and more than that, besides the influence on human and animal physiology, the climatic elements are also responsible for a significant portion of economic activities such as industry, agriculture, commerce, transportation, and others. Therefore, any change in weather patterns has great impact on daily activities, and even more in urban sites, where the most of population is concentrated nowadays. Based on this discussion and concerned in understand the atmospheric structure, this monograph intends to analyze the pattern of atmospheric and temperature element in seven cities of small and medium size located in the state of São Paulo countryside... (Complete abstract click electronic access below)
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Carnival is a unique opportunity for the associations demonstrate the community’s annual work and the float is a major component of this celebration, responsible for pitch the samba using allegories and carry important figures. The excess weight of the floats which are mostly manufactured from truck and bus structures requires larger amount of people to push the vehicle in addition to increased efforts on the steering systems, suspension and wheels, raising the probability of breakage and loss of one year work. The objective of this study is to use the concepts of strength of materials combined with computer simulation to obtain a structure that has the lowest possible weight without compromising the safety of transported components and that is also easy to manufacture, drive and store
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The present study evaluated the mechanical properties of pieces of wood coming from the roof structure of a residence subject fire in the rural area of Itapeva/SP. The structure was built 25 years ago using wooden beams of the species Guarucaia (Peltophorum vogelianum), where the specimens were removed. The research methodology included qualitative evaluation of the samples, estimating the layer pyrolysis and carbonization of the wood, measuring of density and mechanical tests of compression parallel to grain, tension parallel to grain and shear. The mechanical properties of wood were analytically correlated with the layers carbonization and pyrolysis that are influenced by the temperature and time of fire; these values were estimated at 1000 °C and two hours for the case in question. The results indicate that the strength properties of degraded wood are different from a healthy wood. The level of thermodegradation, in general, can be measured by density, result in weight loss due to decomposition of the wooden components.
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Nowadays, there is a search for knowledgment that could be applied in the solution of the problems caused by petrolific activities involving the environment, like the biodiversity preservation and the ecosystems monitoring and management. Foraminifera (Protista) are used as an important tool to the environment characterizarion, because they answer quickly to the fisic-quimic variations and indicate local alterations. The goal of this job is to create models of foraminiferal communities composition through the screening of subsuperficial samples obtained from a core collect from Bertioga Channel, Baixada Santista (SP), trying to understand the influence of the environmental variations along the time upon the indicator species presence, as well as making paleoenvironmentals reconstructions of the area. A 80 cm-core was removed in the outer edge of marsh adjacent to Bertioga Channel, not far from the confluence with the Itapanhaú River. There are presented in abundance, equitability, diversity and species richness obtained in nine samples along the sediment. The lower part of the core is compound by calcareous species (rotalideos and miliolideos) with domain Ammonia (Biofacies 1) and the intermediate and upper parts contain mainly agglutinated species (Biofacies 2 and 3, which is dominated by species of Ammotium). The qualitative and quantitative study of the microfauna of foraminifera present in the core reveals that in recent decades the sampling area passed from a condition of infra-marginal strip under significant coastal marine influence for the condition of inter-coastal swamp covered with mangrove vegetation. This change indicates that the site has undergone a process of sediment progradation, a phenomenon that may have been timely, localized, or a reflection of a relative fall in sea level at the regional level
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The presented text aims to evaluate the causes that led to the formation of the current agrarian structure in Paraguay, Argentina and Uruguay as well as the characteristics of the agro-export model that takes place in these countries, which is based on production and export of soybeans. Because of its contemporary importance and represent the bulk of agricultural production in the countries under study, is established the objective of identifying the particularities and commonalities between these soybean production, with regard to its production structure and the benefits and impacts generated by this. Finally, statistical historical data are presented, enabling this comparison, showing the development and crucial moments for the establishment of the current standard
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There are diseases in vertebrates associated with the structure of bone tissue that directly affect the locomotor system of the animal. Being a endoskeleton, the diagnosis of these diseases becomes difficult in vivo. The characterization of the physical structure of the bone tissue of healthy animals becomes a major tool in the diagnosis comparison of live animals. Thus, the objective of this work is to determine the average value of the key physical properties of the bone structure used in the clinical diagnosis, such as: bone density, porosity, and mass attenuation coefficient of 59.6 keV photons of bone tissue and bovine and equine check variations in these values. The samples were provided by the pathology department of the Faculty of Veterinary Medicine and Zootechny of Botucatu-SP, which are of one male equine and one female bovine animals, using the radio and metacarpus, together with these materials were supplied the historic them. They were withdrawn ten samples in cuts of 10cm over the bone . These samples were submitted to the wet method of immersion in water for the density, by the method of attenuation of gamma radiation of radioisotope 241Am, it is estimated the mass attenuation coefficient, and then were dried in the oven for determining the content moisture. In determining the porosity of the samples was tight ground, in order to obtain the density of particles. The results for the mass attenuation coefficient of gamma radiation to the levels of saturated humidity, environment humidity, dry humidity respectively 0289 ± 0039; 0286 ± 0040 and 0297 ± 0042. And the density of particles was 2.2691 g/cm3
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This work examines the possible effects of successive repair procedures on the microstructure of welded steel SAE 4130 by TIG welding process. Discussions and results were made about the metallographic analysis , non-metallic inclusions and microhardness tests , which were conducted on samples taken from the cradle engine component after the end of its life , a model airplane T-27 Tucano , made by EMBRAER and belonging were performed FAB . The choice of such component is due to the fact that this is critical to flight safety since it provides support for the aircraft engine . Thus regions of the weld metal , base metal and heat affected , with samples of the original weld bead , free of weld bead and also with four rework procedures for TIG welding zone were analyzed . It was found that after the fourth rework there is an increase in the amount of martensite , which may weaken the material with respect to resistance to fatigue. It was also found that the regions of the heat affected zone and weld metal have higher microhardness values when compared to those found in the base metal due to favoring the formation of ferritic and tempered martensite microstructures . Moreover, a welding process promotes a region with less non-metallic inclusions than metal base , which also explains the difference in the results obtained
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Callinectes ornatus tem sua distribuição geográfica no Atlântico ocidental: da Carolina do Norte até a Florida, golfo do México, Antilhas, Colômbia, Venezuela, Guiana e Brasil (Amapá ao Rio Grande ao Sul), ocorrendo em fundos de areia, lama e águas menos salinas podendo alcançar 75 metros de profundidade (Melo, 1996). Essa espécie tem um papel importante na teia trófica marinha, pois possui o habito carnívoro oportunista alimentando se também de detritos, assim controlando a estrutura de várias comunidades bentônicas (Haefner, 1990; Mantelatto & Christofoletti, 2001; Mantelatto et al., 2002). O presente estudo aborda as populações de C. ornatus que vivem no infralitoral não-consolidado das regiões das Ilhas do Mar Virado e das Couves, localizadas no litoral norte do Estado de São Paulo, e teve por objetivo a caracterização dos períodos de recrutamento e reprodutivos da espécie baseado na presença de jovens/adultos e fêmeas ovígeras respectivamente. Os dados utilizados nesse estudo foram coletados do Verão de 1998 á Primavera de 1999 no infralitoral não consolidado das Ilhas do Mar Virado e das Couves totalizando dois anos. As amostragens foram realizadas mensalmente, com auxilio de um barco de pesca equipado com duas redes do tipo “double-rig”. O total coletado durante os dois anos foi de 1164 animais. Os menores indivíduos machos e fêmeas encontrados na Ilha do Mar Virado apresentam os seguintes tamanhos respectivamente 22,2 mm e 17,7 mm, já na Ilha das Couves foram de 20,2 mm e de 32,3 mm. Foi obtido um total de 12 classes de tamanho, com 5,0 mm de amplitude. As duas primeiras classes foram ocupadas apenas por indivíduos jovens já as cinco ultimas principalmente por indivíduos adultos e fêmeas ovígeras. Para os indivíduos machos adultos foi possível observar o deslocamento de modas da Primavera de 1998 à Primavera de 1999... (Resumo completo, clicar acesso eletrônico abaixo)
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This project has several objectives: To determine medium values and variations of the density, porosity, humidity, shrinkage volume and the coefficient of mass attenuation of gamma radiation of 59,6 keV of the radioisotope 241Am, using samples of equine radio, in growth and adult. The samples of bones were supplied by the Department of Pathology of University of Veterinary Medicine and Zootechnics - UNESP campus Botucatu. Bones of the paws front left of two males were used. Of each bone ten samples were removed. Those samples were prepared to just obtain compact bony fabric, being submitted to the rehearsal of determination of the density by the immersion method in water and determination of the coefficient attenuation lineal for the method of attenuation of the radiation of the 241Am, also obtaining your humidity content. Still, they were obtained new samples starting from the ground samples and verified the density of the particles present in that, obtaining the medium value of the coefficient of mass attenuation. The results showed the medium values and significant statistical variations of the density, porosity, humidity, shrinkage volume and coefficient of mass attenuation of gamma radiation of 59, 6 keV of the radioisotope 241Am in the samples, establishing some relationships between of the certain physical parameters with biological aspects and possible existent influences between them
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The steel type AISI 4130 (ultra-high strength steel) is an alloy of low carbon and its main alloying elements are chromium and molybdenum, which improves the toughness of the weld metal. It has numerous applications, especially where the need for high mechanical strength. It is widely used in equipment used by the aviation industry, such as cradle-tomotor, and this is the motivation for this study. Cots are of fundamental importance, because the engine supports and maintains balance in the fixed landing gear. This equipment is subjected to intense loading cycles, whose fractures caused by fatigue are constantly observed. Will be determined the effects caused by re-welding the structure of aeronautical equipment, and will also study the microstructure of the metal without welding. The studies will be done on materials used in aircraft, which was given to study. The results provide knowledge of microstructure to evaluate any type of fracture that maybe caused by fatigue. Fatigue is a major cause of aircraft accidents and incidents occurred, which makes the study of the microstructure of the metal, weld and re-solder the knowledge essential to the life of the material. The prevention and control of the process of fatigue in aircraft are critical, since the components are subjected to greater responsibility cyclic loading
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O objetivo do presente estudo foi avaliar a estrutura de população de O. maculata, através de sua distribuição espacial e estrutura de habitat, comparando características físicas e biológicas em diferentes fisionomias de Pinus spp. e Eucalyptus spp.. Foram montadas 86 parcelas de 5m por 10m, distribuídas uniformemente entre 4 áreas pré-estabelecidas de fisionomias distintas. Os indivíduos levantados foram separados em duas classes etárias, jovens e adultos, e contabilizou-se a taxa de predação, número de pseudobulbos e número de folhas. Os parâmetros ambientais avaliados foram cobertura herbácea, densidade de dossel, luminosidade e umidade de serrapilheira. A espécie apresentou densidades bastante elevadas nas áreas de plantios de eucalipto (1224 e 1733 indivíduos por hectare) e baixas nos plantios de pinus (88 e 26 individuos por hectare) o que levou as análises a se concentrarem nas fisionomias compostas por eucaliptos. O padrão de distribuição da espécie foi o agregado em todos os ambientes. Indivíduos adultos apresentaram significativamente um número médio de pseudobulbos maior que indivíduos jovens (Mann-Whitney; U = 24248.500; p<0,001), porém a diferença no número de folhas não foi significativa. A taxa de predação foliar em O. maculata entre as áreas de eucaliptos apresentou variação significativa. A variação do total de folhas predadas foi confirmada pelo teste Qui-quadrado de Pearson (X²=115.487; gl=1; p<0.001). A comparação de médias, com base no teste de Kruskal-Wallis, para cobertura de dossel (H(3,N=102)=28,534 p<0,001) e cobertura herbácea H(3,N=94)=28,246, p<0,001, mostrou taxas menores nas áreas de eucalipto. A umidade da serrapilheira foi menor (36,5%) nos locais onde a espécie apresentou agrupamentos, quando comparada aos locais de ausência (47,5%). Oeceoclades maculata Lindl. possui grande capacidade para colonizar ambientes... (Resumo completo, clicar acesso eletrônico abaixo)