9 research outputs found

    Carga máxima de fósforo admissível ao reservatório Piraquara II, uma aplicação do processo TMDL Maximum allowable phosphorus load in the Piraquara II reservoir, a TMDL process application

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    Para implementação e operacionalização da política brasileira de recursos hídricos, é imprescindível o uso de ferramentas de planejamento que considerem o efeito de todas as atividades ou processos que causam ou contribuem para a degradação da qualidade de um corpo d'água. Neste sentido, aplicou-se o processo TMDL (total maximum daily load), desenvolvido pela Agência de Proteção Ambiental dos Estados Unidos (EPA), para o P, na área de drenagem de contribuição ao futuro reservatório Piraquara II, bacia hidrográfica do rio Piraquara, Paraná. O processo TMDL determina a quantidade máxima de cargas de um poluente que um corpo d'água pode receber sem violar os padrões estabelecidos de qualidade da água e aloca cargas deste poluente entre fontes de poluição pontuais e difusas. No presente estudo, utilizou-se o método TMDL, com o objetivo de demonstrar ser ele uma ferramenta útil no processo de gestão dos recursos hídricos. Simularam-se cenários de uso do solo, por meio de modelagem matemática, até obter-se uma concentração de P total no reservatório abaixo da faixa limite para ocorrência de eutrofização, de 0,025 a 0,10 mg L-1, estabelecida no estudo. Realizou-se uma simulação de uso atual do solo, visando prever a condição inicial de qualidade da água no corpo d'água, na qual a concentração de P total no reservatório resultante não atendeu ao padrão estabelecido. Procedeu-se a uma segunda simulação com adoção das medidas de controle, recomposição de mata ciliar e plantio direto, para reduzir a exportação de carga de P total da bacia. Obteve-se uma melhoria na qualidade da água do reservatório, indicando que as medidas adotadas foram suficientes para atingir o padrão estabelecido, o que demonstra a aplicabilidade do método.<br>For the implementation and operation of the Brazilian Federal law on water resources of 1997 it is indispensable to use planning tools that take into account the effect of all activities or processes that cause or contribute to the loss of quality of a waterbody. For this purpose, the nutrient phosphorus was evaluated by the TMDL (total maximum daily load) process developed by the United States Environmental Protection Agency - EPA in the drainage area of contribution to the future Piraquara II Reservoir, Piraquara River Watershed, Paraná State, Brazil. The TMDL process determines the maximum amount of a pollutant load a waterbody can receive without violating the established water quality standards, and allocates loads of this pollutant between point and nonpoint sources. In the present research the TMDL methodology was used to demonstrate its usefulness in the management of water resources. Sceneries of soil use were simulated by mathematic modeling to define a total phosphorus concentration in the reservoir under the limit range for eutrophication established in the study (0.025-0.10 mg L-1 of P). The current soil use was simulated aiming to foresee the initial condition of water quality in the waterbody. The data obtained indicate that the resulting total phosphorus concentration in the reservoir did not meet the established standard. In a second simulation with adoption of potential control measures, such as recomposed riparian areas and no-till systems, the exportated total phosphorus load from the watershed decreased. With adoption of such conservation measure the simulated water quality of the reservoir improved and attained the established standard, demonstratig the applicability of the methodology

    Hepatocellular carcinoma recurrence after liver transplantation in a brazilian multicenter study : clinical profile and prognostic factors of survival

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    Liver transplantation (LT) is the treatment of choice for patients with unresectable early hepatocellular carcinoma (HCC). Post-LT HCC recurrence rates range from 8 to 20% and still impact on overall survival (OS). The aim of our study was to evaluate the impact of HCC recurrence on post-LT survival and analyze prognostic factors among those patients with recurrence. We carried out a national, multicenter, retrospective cohort study in Brazil. Medical records of 1119 LT recipients with HCC were collected. Data from patients with post-LT HCC recurrence were analyzed and correlated with post-relapse survival. OS of the 1119 patients included in the study was 63% over 5 years. Post-LT HCC recurrence occurred in 86 (8%) patients. The mean time to recurrence was 12 months. Sites of recurrence were extrahepatic in 55%, hepatic in 27%, and both hepatic and extrahepatic in 18%. Recurrence treatment was performed in 50 (64%) cases, mostly with sorafenib. Post-relapse survival rates were 34% at 1 year and 13% at 5 years. Univariable analysis identified alpha-fetoprotein more than 1000 ng/ml at relapse, recurrence treatment, extrahepatic location, and time to recurrence more than 2 years as prognostic factors. In multivariable analysis, recurrence treatment, extrahepatic location, and time to recurrence more than 2 years were independent predictors of better survival. In a large Brazilian cohort of LT recipients with HCC, post-LT HCC recurrence occurred in 8% and impacted significantly on the OS. Patients with early recurrence presented a worse prognosis. However, treatment of recurrence improved outcomes, highlighting the importance of early diagnosis3191148115

    A Bibliographic Contribution to the Study of Portuguese Africa (1965–1972)

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