888 resultados para Alterações climáticas - Efeitos fisiológicos


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

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Pós-graduação em Agronomia (Horticultura) - FCA

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Pós-graduação em Geografia - IGCE

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The present work evaluated the effect of strobilurins, boscalid, plant growth regulators and vegetal extracts on the physico-chemical quality of tomato fruits (Solanum lycopersicum L.), hybrid Giuliana. The fruits from each treatment were selected and separated in 4 repetitions: control, pyraclostrobin, boscalid, pyraclostrobin + boscalid, IBA + GA(3) + kinetin, GA(4+7) + benzylaminopurine and vegetal extract. The first application was carried out at 30 days after transplant and the following at every 15 days. The evaluations were: weight loss, titratable acidity (TA), soluble solids (SS), SS/TA relation, pH, ascorbic acid content, texture, total soluble sugars (TSS), activity of pectin methyl esterase (PME) and polygalacturonase (PG). The SS content, responsible for fruit flavor, varied accordingly to the treatment, being highest for GA(4+7) + benzylaminopurine and lowest for the control. The same occurred regarding the SS/AT relation. The fruits were kept on the shelf for 9 days, at room temperature, being that at the end of this period several treatments still presented fruit in optimal consumption conditions, notably the boscalid treatment, which presented lowest weight loss, followed by pyraclostrobin. Therefore, it can be concluded that the application of the treatments did not modify the values for pH, AT and AST of the fruits. The highest PME activity was observed for the treatments with boscalid and the mixture of boscalid and pyraclostrobin, while the lowest PG activity occurred in the control and the pyraclostrobin treatment, indicating that some products accelerated the process of demethylation of pectins by PME, facilitating the action of PG.

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Pós-graduação em Agronomia (Horticultura) - FCA

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Pós-graduação em Agronomia (Horticultura) - FCA

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Dissertação para obtenção do grau de Mestre no Instituto Superior de Ciências da Saúde Egas Moniz

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Fundamentar as acompetências a adquirir pelo estudante

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As alterações climáticas impuseram modificações significativas na estrutura e dinâmica natural dos ecossistemas costeiros comprometendo as suas capacidades de resiliência cujos limites têm sido ultrapassados. A falta de políticas integradas de gestão territorial e adaptação às alterações climáticas intensificaram os riscos e vulnerabilidades sócio- ambientais em muitos espaços costeiros. Este trabalho foi realizado no município de Luanda onde a erosão, as inundações e os movimentos de massa são uma realidade cada vez mais preocupante. A metodologia de investigação para este trabalho contou com as consultas aos decisores políticos, população e ONGs presididas por inquéritos por questionário e entrevistas semi-estruturadas com primado para os aspectos qualitativos. As principais fontes de consulta foram as institucionais e os repositórios científicos de diversas universidades assim como a recolha bibliográfica. Os resultados obtidos apontam claramente para a falta de participação activa dos munícipes em processos de formação e tomada de iniciativas em sede de políticas ambientais, a gestão insustentável da zona costeira, o baixo grau de percepção ambiental e a falta de articulação integrada das instituições quanto ao ambiente.

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Dissertação de Mestrado para obtenção do grau de Mestre em Arquitectura com Especialização em Urbanismo, apresentada na Faculdade de Arquitectura da Universidade Técnica de Lisboa.

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Face ao aumento que se tem vindo a observar da população, especialmente a população flutuante, e a alteração nos hábitos de consumo de água, com destaque para os últimos 20 anos, a região do Algarve poderá enfrentar em anos secos um cenário onde a disponibilidade de recursos hídricos naturais seja reduzida face à procura. Em 2005 foi desenvolvido um plano de contingência para o Sistema Multimunicipal de Abastecimento de Água do Algarve (SMAAA). O plano prevê a possibilidade de reactivação de antigas captações subterrâneas municipais para reforço do abastecimento público em situações de contingência nesta região. A presente dissertação apresenta a avaliação dos principais impactos das projecções dos modelos de clima para o fim do século no SMAAA, nomeadamente ao nível da disponibilidade de água na origem e da procura de água para consumo humano, e a adaptação do plano de contingência face a esses impactos. /RESUME: Faced with a population increase, special one related with tourism, and also with changes in water consumption habits that has been occurring mostly in the last 20 years, the Algarve region in hydrologic dry years may face serious water shortage in a scenario where water resources are scarce. Being so, in 2005 a contingency plan was developed for the Algarve's Multimunicipal Bulk System (AMBS). The plan includes the possibility of reactivating old water capitations, to reinforce the water public distribution upon contingency situation in the region. The present dissertation evaluates the main impacts of the climatic change forecasted by model projections throughout the end of the century on the AMBS, Iooking more specifically at the water availability and the water demand for public consumption, and the adaptation of the contingency plan to those impacts.

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Visando conhecer as interações entre fungos micorrízicos arbusculares e bactérias diazotróficas na cultura da mandioca (Manihot esculenta Crantz), foram conduzidos vários experimentos para avaliar os efeitos de exsudatos de mandioca e de bactérias nos fungos micorrízicos, e a produção de ácido indolacético (AIA) in vitro pelas bactérias diazotróficas. Os experimentos evidenciaram que as bactérias diazotróficas estimularam a colonização micorrízica de Glomus clarum a partir do 30o dia. Os exsudatos de mandioca e das bactérias não apresentaram efeito na germinação de Gigaspora gigantea, mas influenciaram seu crescimento micelial. A adição de exsudatos de mandioca estimulou o crescimento das bactérias diazotróficas in vitro, evidenciando que podem existir, nos exsudatos, substâncias que atuariam como sinais moleculares ou estimulantes do crescimento, e não como fatores nutricionais. As bactérias diazotróficas apresentam ainda capacidade de produzir AIA in vitro. Azospirillum lipoferum isolado da mandioca produziu até 130 mM de AIA após 48 horas de incubação, ao passo que Klebsiella sp. produziu cerca 60 mM e a Bactéria E, aproximadamente 20 mM.

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During the last century mean global temperatures have been increasing. According to the predictions, the temperature change is expected to exceed 1.5ºC in this century and the warming is likely to continue. Freshwater ecosystems are among the most sensitive mainly due to changes in the hydrologic cycle and consequently changes in several physico-chemical parameters (e.g. pH, dissolved oxygen). Alterations in environmental parameters of freshwater systems are likely to affect distribution, morphology, physiology and richness of a wide range of species leading to important changes in ecosystem biodiversity and function. Moreover, they can also work as co-stressors in environments where organisms have already to cope with chemical contamination (such as pesticides), increasing the environmental risk due to potential interactions. Therefore, the objective of this work was to evaluate the effects of climate change related environmental parameters on the toxicity of pesticides to zebrafish embryos. The following environmental factors were studied: pH (3.0-12.0), dissolved oxygen level (0-8 mg/L) and UV radiation (0-500 mW/m2). The pesticides studied were the carbamate insecticide carbaryl and the benzimidazole fungicide carbendazim. Stressors were firstly tested separately in order to derive concentration- or intensity-response curves to further study the effects of binary combinations (environmental factors x pesticides) by applying mixture models. Characterization of zebrafish embryos response to environmental stress revealed that pH effects were fully established after 24 h of exposure and survival was only affected at pH values below 5 and above 10. Low oxygen levels also affected embryos development at concentrations below 4 mg/L (delay, heart rate decrease and edema), and at concentrations below 0.5 mg/L the survival was drastically reduced. Continuous exposure to UV radiation showed a strong time-dependent impact on embryos survival leading to 100% of mortality after 72 hours of exposure. The toxicity of pesticides carbaryl and carbendazim was characterized at several levels of biological organization including developmental, biochemical and behavioural allowing a mechanistic understanding of the effects and highlighting the usefulness of behavioural responses (locomotion) as a sensitive endpoint in ecotoxicology. Once the individual concentration response relationship of each stressor was established, a combined toxicity study was conducted to evaluate the effects of pH on the toxicity of carbaryl. We have shown that pH can modify the toxicity of the pesticide carbaryl. The conceptual model concentration addition allowed a precise prediction of the toxicity of the jointeffects of acid pH and carbaryl. Nevertheless, for alkaline condition both concepts failed in predicting the effects. Deviations to the model were however easy to explain as high pH values favour the hydrolysis of carbaryl with the consequent formation of the more toxic degradation product 1- naphtol. Although in the present study such explanatory process was easy to establish, for many other combinations the “interactive” nature is not so evident. In the context of the climate change few scenarios predict such increase in the pH of aquatic systems, however this was a first approach focused in the lethal effects only. In a second tier assessment effects at sublethal level would be sought and it is expectable that more subtle pH changes (more realistic in terms of climate changes scenarios) may have an effect at physiological and biochemical levels with possible long term consequences for the population fitness.