Ancoragens em estruturas portuárias. Análise de um caso de obra

Dissertação para obtenção do Grau de Mestre em Engenharia Geológica

Caracterização de estruturas coerentes em leitos vegetados

Dissertação para obtenção do Grau de Mestre em Engenharia Civil

Morphometric study of the fibrosis and mast cell count in the circular colon musculature of chronic Chagas patients with and without megacolon

A morphometric study of the circular colon musculature was performed, in which the mast cell count was determined and the connective fibrous tissue in this layer was measured. The objective was to gain better understanding of Chagas megacolon morphology and contribute towards the knowledge of fibrosis pathogenesis in Chagas megas. An evaluation was made of 15 distal sigmoid rings from Chagas patients with megacolon (MCC), 15 without megacolon (CSMC) and 15 non-Chagas patients (NC). The rings were fixed in formol, embedded in paraffin, and 7mm thick sections were cut and stained using Azan-Heidenhain and Giemsa. The mast cell count and fibrosis were greater in the MCC group than in the CSMC and NC groups (p < 0.05; Kruskal-Wallis test) and there was no significant difference between the latter two. The fibrosis and increased mast cell count in the colon musculature of the MCC group possibly indicates that there is a relationship between mastocytosis and fibrosis, as has already been demonstrated in other pathologies.

Occurrence and variability of Panstrongylus lutzi in the State of Ceará, Brazil

Panstrongylus lutzi is generally restricted to the "caatinga" areas of north-eastern Brazil. Adult insects are frequently found in local houses, but colonies have not previously been registered in the statistics of the Control Programme of Chagas Disease. In Ceará State, our study revealed increasing occurrence of this species, usually with high infection rates for Trypanosoma cruzi, and always represented by adults that invaded the artificial environment. We also found nymphs in the peridomicile and inside the houses. In silvatic habitats we collected two adult females from hollow tree trunks, which may represent an alternative natural ecotope for the species in this state. Panstrongylus lutzi entomological collections from Sobral and Crateús, studied by morphology and morphometrics, showed great variability; those from Crateús were larger smaller and paler in colour, with individuals showing genital features consistent with those described for Panstrongylus lutzi or Panstrongylus sherlocki, whereas those from Sobral were darker and with genitalia compatible with P. sherlocki, nevertheless, all were considered to be Panstrongylus lutzi.

Plano de emergência interno de barragens

A existência de barragens em determinadas secções de um rio conduz, na maioria dos casos, a benefícios locais e regionais tais como a possibilidade de regular o caudal fluvial, a produção de energia elétrica ou o abastecimento de água às populações ou às atividades agrícolas. Por outro lado, impactos sociais e ambientais negativos e o risco de uma possível rotura encontram-se entre os maiores problemas provocados pela existência dessas estruturas. No presente documento apresenta-se um estudo relativo ao planeamento de emergência em barragens, mais precisamente aos Planos de Emergência Internos de Barragens. É efetuada uma análise da legislação nacional relativa ao planeamento de emergência, nomeadamente no que diz respeito ao Plano de Emergência Interno conforme publicado no Regulamento de Segurança de Barragens (Decreto-Lei 344/2007 de 15 de Outubro). O trabalho apresentado inclui ainda a sistematização dos principais aspetos que devem ser incluídos no Planeamento de Emergência de Barragens de acordo com a legislação portuguesa, e a comparação com o que é exigido em diferentes países da União Europeia. Além do trabalho de pesquisa e recolha de informação, analisam-se as principais diferenças entre as metodologias de planeamento de emergências em barragens em Portugal, Espanha, França e Reino Unido, aplicando as diferentes abordagens a um caso de estudo, nomeadamente a Barragem da Bravura. Para esse caso de estudo, aprofundou-se a componente hidráulica do Plano de Emergência Interno, com a simulação da onda de cheia provocada pela rotura da barragem. A exigência a nível do resultado das simulações para cada país foi comparada.

Análise computacional da evolução da hidromorfologia do Baixo Mondego em resultado da subida do nível do mar

O êxito na previsão das consequências da subida do nível do mar à escala global está dependente de uma correcta análise de todos fenómenos que daí poderão resultar. Neste âmbito, o presente estudo incide sobre o efeito da subida do nível do mar na hidromorfologia de rios, parâmetro que não é com frequência um dado de entrada nas simulações numéricas em estudos e projectos de Hidráulica Fluvial. Desenvolveu-se um modelo computacional na linguagem de programação Fortran (FTN 95), que permite simular a longo prazo a evolução do fundo móvel e da superfície livre de um rio. É um modelo de dinâmica sedimentar, unidimensional, que simula escoamentos em regime quase-permanente e em canais de topografia simples, utilizando a fórmula de Engelund-Hansen para o transporte sólido. O modelo foi aplicado no trecho mais a jusante do Mondego, desde Coimbra até à foz no Atlântico, onde o rio flui na zona do chamado Baixo Mondego, planície aluvial, alvo de grandes alterações antropogénicas, nomeadamente obras de regularização fluvial. As que foram realizadas no séc. XVIII modificaram o original percurso do rio atribuindo-lhe uma topografia simples, mas não resolveram o seu principal problema, o excesso de assoreamento a jusante de Coimbra, tendo como consequência frequentes inundações e cheias. Estas obras colocaram em evidência a grande vulnerabilidade do rio aos problemas de transporte sólido e assoreamento. Mais tarde, em finais do séc. XX, as obras realizadas na sequência do Plano de Aproveitamento do Baixo Mondego vieram, de uma forma integrada, contribuir para o seu equilíbrio hidromorfológico. Actualmente, face à subida do nível do mar volta a colocar-se a questão do assoreamento a jusante de Coimbra. Logo, é importante conhecer as previsões a longo prazo de dinâmica sedimentar deste troço, para a sua adequada gestão. Foram realizadas previsões para 20 cenários num horizonte temporal de 100 anos, todos eles consideram o caudal dominante calculado para o rio e variam de acordo com a subida do nível do mar, o caudal sólido e diâmetro médio dos sedimentos. Os resultados obtidos foram os previstos qualitativamente, isto é, a subida do nível do mar poderá alterar o leito aluvionar, elevando as cotas de fundo e aumentando os volumes de assoreamento.

Length and caliber of the rectosigmoid colon among patients with Chagas disease and controls from areas at different altitudes

Introduction In this study, we investigated radiological changes in the sigmoid colon in chagasic patients by comparing their colon lengths and caliber with those of non-chagasic living in the same region and non-chagasic living at high altitudes. Methods A total of 317 individuals were evaluated using clinical, serological and radiological methods and divided into three groups: 1) one hundred and nine non-chagasic individuals from Uberaba, Brazil; 2) sixty-one non-chagasic from Puno, Peru; 3) one hundred forty-seven chagasics examined in Uberaba, being 62 without megacolon (3A), 72 with megacolon (3B) and 13 with doubtful diagnosis of megacolon (3C). Results In group 2, the sigmoid colon had a significantly larger caliber (p=0.001) and the rectosigmoid colon was longer (p<0.001) than group 1. In subgroup 3A, the sigmoid colon (p<0.001) and rectum (p<0.001) had a significantly larger caliber and the rectosigmoid was longer (p<0.001) than that of the non-chagasic individuals. In subgroup 3B, the rectosigmoid was longer in all patients, and the caliber of the sigmoid was significantly larger than that of subjects in subgroups 3A and 3C (p<0.001). Conclusions Morphometric analysis confirms that Chagas disease may increase the caliber and length of the rectosigmoid. Our results suggest that altitude, ethnicity and diet may have influenced the size and length of the rectosigmoid of andean patients.

Effects of ocean acidification on the swimming ability, development and biochemical responses of sand smelt larvae

Ocean acidification, recognized as a major threat to marine ecosystems, has developed into one of the fastest growing fields of research in marine sciences. Several studies on fish larval stages point to abnormal behaviours, malformations and increased mortality rates as a result of exposure to increased levels of CO2. However, other studies fail to recognize any consequence, suggesting species-specific sensitivity to increased levels of CO2, highlighting the need of further research. In this study we investigated the effects of exposure to elevated pCO2 on behaviour, development, oxidative stress and energy metabolism of sand smelt larvae, Atherina presbyter. Larvae were caught at Arrábida Marine Park (Portugal) and exposed to different pCO2 levels (control: ~600μatm, pH=8.03; medium: ~1000μatm, pH=7.85; high: ~1800μatm, pH=7.64) up to 15days, after which critical swimming speed (Ucrit), morphometric traits and biochemical biomarkers were determined. Measured biomarkers were related with: 1) oxidative stress - superoxide dismutase and catalase enzyme activities, levels of lipid peroxidation and DNA damage, and levels of superoxide anion production; 2) energy metabolism - total carbohydrate levels, electron transport system activity, lactate dehydrogenase and isocitrate dehydrogenase enzyme activities. Swimming speed was not affected by treatment, but exposure to increasing levels of pCO2 leads to higher energetic costs and morphometric changes, with larger larvae in high pCO2 treatment and smaller larvae in medium pCO2 treatment. The efficient antioxidant response capacity and increase in energetic metabolism only registered at the medium pCO2 treatment may indicate that at higher pCO2 levels the capacity of larvae to restore their internal balance can be impaired. Our findings illustrate the need of using multiple approaches to explore the consequences of future pCO2 levels on organisms.

Post-splenectomy infections in chronic schistosomiasis as a consequence of bacterial translocation

INTRODUCTION : Bacterial translocation is the invasion of indigenous intestinal bacteria through the gut mucosa to normally sterile tissues and internal organs. Schistosomiasis may cause alterations in the immune system and damage to the intestines, portal system and mesenteric lymph nodes. This study investigated bacterial translocation and alterations in the intestinal microbiota and mucosa in schistosomiasis and splenectomized mice. METHODS : Forty female 35-day-old Swiss Webster mice were divided into the following four groups with 10 animals each: schistosomotic (ESF), splenectomized schistosomotic (ESEF), splenectomized (EF) and control (CF). Infection was achieved by introduction of 50 Schistosoma mansoni (SLM) cercariae through the skin. At 125 days after birth, half of the parasitized and unparasitized mice were subjected to splenectomy. Body weights were recorded for one week after splenectomy; then, the mice were euthanized to study bacterial translocation, microbiota composition and intestinal morphometry. RESULTS : We observed significant reductions in the weight increases in the EF, ESF and ESEF groups. There were increases of at least 1,000 CFU of intestinal microbiota bacteria in these groups compared with the CF. The EF, ESF and ESEF mice showed decreases in the heights and areas of villi and the total villus areas (perimeter). We observed frequent co-infections with various bacterial genera. CONCLUSIONS : The ESEF mice showed a higher degree of sepsis. This finding may be associated with a reduction in the immune response associated with the absence of the spleen and a reduction in nutritional absorption strengthened by both of these factors (Schistosoma infection and splenectomy).

Morphologic and morphometric evaluation of pancreatic islets in chronic Chagas' disease

PURPOSE: Hyperglycemia and abnormal glucose tolerance tests observed in some patients with chronic Chagas' disease suggest the possibility of morphological changes in pancreatic islets and/or denervation. The purpose of this study was to describe the morphology and morphometry of pancreatic islets in chronic Chagas' disease. METHODS: Morphologic and computerized morphometric studies were performed in fragments of the head, body, and tail regions of the pancreas obtained at necropsies of 8 normal controls and 17 patients with chronic Chagas' disease: 8 with the digestive form (Megas) and 9 with the congestive heart failure form. RESULTS: The Megas group had a larger (p < 0.05) pancreatic islet area in the tail of the pancreas (10649.3 ± 4408.8 µm²) than the normal control (9481.8 ± 3242.4 µm²) and congestive heart failure (9475.1 ± 2104.9 µm²) groups; likewise, the density of the pancreatic islets (PI) was greater (1.2 ± 0.7 vs. 0.9 ± 0.6 vs. 1.9 ± 1.0 PI/mm², respectively). In the tail region of the pancreas of patients with the Megas form, there was a significant and positive correlation (r = +0.73) between the area and density of pancreatic islets. Discrete fibrosis and leukocytic infiltrates were found in pancreatic ganglia and pancreatic islets of the patients with Chagas' disease. Trypanosoma cruzi nests were not observed in the examined sections. Individuals with the Megas form of Chagas' disease showed increased area and density of pancreatic islets in the tail of the pancreas. CONCLUSION: The observed morphometric and morphologic alterations are consistent with functional changes in the pancreas, including glycemia and insulin disturbances.

GEOCHEMISTRY AND GEOCHRONOLOGY OF SURFICIAL ACRE BASIN SEDIMENTS (WESTERN AMAZONIA): KEY INFORMATION FOR CLIMATE RECONSTRUCTION.

Geochemical and geochronological analyses of samples of surficial Acre Basin sediments and fossils indicate an extensive fluvial-lacustrine system, occupying this region, desiccated slowly during the last glacial cycle (LGC). This research documents direct evidence for aridity in western Amazonia during the LGC and is important in establishing boundary conditions for LGC climate models as well as in correlating marine and continental (LGC) climate conditions.

LAGO AMAZONAS: FACT OR FANCY?

It has been suggested that a huge lake, Lago Amazonas, covered a large part of the Amazon basin until as recently as two thousand years ago. According to this hypothesis, the topmost sediments in western Amazonia are almost universally young deposite of lacustrine and deltaic origin. The hypothesis has gained some attention among biologists because of its implications for biological phenomena in Amazonia, especially biogeography and biodiversity. According to the available geological data, however, Amazonia is geologically far more complex than assumed by the lake hypothesis. In the following discussion we will point out the weaknesses of the Lago Amazonas hypothesis, and indicate alternative explanations of the surface geology that are based on tectonically controlled fluvial deposition.

Uma revisão geral sobre o clima da Amazônia

Este trabalho busca apresentar, de uma maneira compacta, os principais resultados científicos já alcançados pela comunidade brasileira e mundial sobre pesquisas na Amazônia. Aborda-se o paleoclima da região, bem como as características atuais, em termos de temperatura do ar e da distribuição de chuvas. São discutidos os principais sistemas atmosféricos atuantes na região, tais como linhas de instabilidade, brisa fluvial, teleconexões com El-Niño, interação com sistemas frontais no sul do país, friagens, além da variabilidade do clima nas escalas interanuais e de longo-prazo. Tendo em vista as altas taxas de desmatamento em algumas partes da Amazônia, são discutidos as principais modificações microclimáticas e resultados obtidos por simulações numéricas devido à substituição de floresta tropical por áreas de pastagens. Finalizando, é apresentado um resumo dos vários experimentos micrometeorológicos que ocorreram na Amazônia nas últimas duas décadas.

Características sedimentares fluviais associadas ao grau de reservação da mata Ciliar - Rio Urumajó, Nordeste Paraense

Os rios são os agentes mais importantes no transporte dos sedimentos para as áreas mais baixas dos continentes e para o mar. Além dos efeitos diretos do clima local, a cobertura vegetal atua no controle da descarga e no suprimento de sedimentos. Sendo assim, o presente trabalho enfoca o padrão de distribuição granulométrica do rio Urumajó (nordeste paraense) em relação ao estado de preservação da mata ciliar. Cinco estações (A-E) foram estabelecidas de forma a registrar um transecto da nascente à foz do rio. Nessas estações, procedeu-se com a caracterização da mata ciliar, bem como do seu grau de preservação. Além disto, elaborou-se um perfil transversal ao canal para cada estação, com coleta de cinco amostras de sedimentos em cada perfil. Estes foram submetidos à análise granulométrica, que resultou na obtenção de valores da média, mediana, seleção, assimetria e curtose. Com os resultados foi possível reconhecer as características sedimentares normais do rio, onde areia média é a principal classe granulométrica transportada. Foram observadas nas estações A e C a clara tendência das amostras serem moderadamente bem selecionadas e aproximadamente simétricas, com dominância absoluta de areia média, o que está diretamente relacionado ao seu bom estado de preservação. Significativas variações granulométricas nas estações B, D e E foram associadas com o processo erosivo das margens do rio, conseqüência da degradação da mata ciliar. Além disso, foi constatada a influência das correntes de maré na sedimentologia da estação E, subsidiando também a delimitação do ambiente estuarino que se encontra associado ao canal fluvial.

Vegetational changes during the last millennium inferred from a palynological record from the Bananal Island, Tocantins, Brazil

The Bananal Island is regarded the largest fluvial island in the world, bounded by Araguaia and Javaés rivers, being located in southwest of Tocantins. The objectives of this work were to provide information about the vegetational changes that occurred at the Bananal Island, in order to contribute to the understanding the dynamics of past and current savanna and areas of ecotones with forests. Thus, a sedimentary core collected from a small lake at the Bananal Island plain was submitted to pollen and radiocarbon dating analyses. The results showed that the last millennium was dominated by forest reflecting a wet climate. At the beginning of the record (920-770 yr cal BP) the wet climate and high rainfall produced flooding during long rainy seasons that maintained the Javaés River connected to the studied lake, and hence, this environment was marked by the presence of a homogenous forest rich in Moraceae/Urticaceae, due to flooded soils occurrence. During the following period (770-304 yr cal BP) the reduced rainfall and shortening of the rainy seasons isolated the lake from the Javaés River for long periods, which caused a diversification of the forest and gave rise to the appearance of the components of floodplain forest and marsh vegetation adapted to waterlogged soils. Since 304 years cal BP to the present day this environment remained dominated by this diverse forest and the lacustrine conditions were also similar to previous phase, with a slight increase of moisture in the last 84 years that caused the increase of Piranhea.