Multitemporal analysis of estimated soil loss for the river Mourão watershed, Paraná – Brazil / Análise multitemporal da perda de solo estimada para a bacia hidrográfica do rio Mourão, Paraná – Brasil

The multitemporal behavior of soil loss by surface water erosion in the hydrographic basin of the river Mourão in the center-western region of the Paraná state, Brazil, is analyzed. Forecast was based on the application of the Universal Soil Loss Equation (USLE) with the data integration and estimates within an Geography Information System (GIS) environment. Results had shown high mean annual rain erosivity (10,000 MJ.mm.ha–1.h–1.year–1), with great concentration in January and December. As a rule, soils have average erodibilities, exception of Dystroferric Red Latisol (low class) and Dystrophic Red Argisol (high class). Although the topographic factor was high (>20), rates lower than 1 were predominant. Main land uses comprise temporal crops and pasture throughout the years. The watershed showed a natural potential for low surface erosion. When related to usage types, yearly soil loss was also low (<50 ton.ha–1.year–1), with more critical scores that reach rates higher than 150 ton.ha–1.year–1. Soil loss over the years did not provide great distinctions in distribution standards, although it becames rather intensified in some sectors, especially in the center-eastern and southwestern sections of the watershed.

Resumo Este estudo visa analisar o comportamento multitemporal da perda de solo por erosão hídrica laminar na bacia hidrográfica do rio Mourão, localizada na região centro-ocidental do Estado do Paraná – Brasil. A predição foi baseada na aplicação da Equação Universal de Perdas de Solo (USLE), com integração dos dados e estimativas realizados em ambiente SIG (Sistema de Informações Geográficas). Os resultados mostram elevada erosividade da chuva média anual (10.000 MJ.mm.ha–1.h–1.ano–1). Os solos apresentam, em geral, média erodibilidade, com exceções do Latossolo Vermelho Distroférrico (classe baixa) e o Argissolo Vermelho Distrófico (classe alta). O fator topográfico atingiu índices elevados (>20), no entanto, predominaram os valores inferiores a 1. Os tipos de usos principais são as lavouras temporárias e pastagem, para todos os anos. A bacia apresentou Potencial Natural a Erosão laminar predominante baixo, quando relacionado aos tipos de usos resultou numa perda de solo anual estimada também baixa (<50 ton.ha–1.ano–1), com pontos mais críticos que atingem valores superiores a 150 ton.ha–1.ano–1. A perda de solo entre os anos não apresentou grandes distinções nos padrões de distribuição, apenas intensificou-se em alguns setores, como nas porções centro-leste e sudoeste da bacia.

Multitemporal analysis of estimated soil loss for the river Mourão watershed, Paraná Brazil

The multitemporal behavior of soil loss by surface water erosion in the hydrographic basin of the river Mourão in the center-western region of the Paraná state, Brazil, is analyzed. Forecast was based on the application of the Universal Soil Loss Equation (USLE) with the data integration and estimates within an Geography Information System (GIS) environment. Results had shown high mean annual rain erosivity (10,000 MJ.mm.ha1.h1.year1), with great concentration in January and December. As a rule, soils have average erodibilities, exception of Dystroferric Red Latisol (low class) and Dystrophic Red Argisol (high class). Although the topographic factor was high (>20), rates lower than 1 were predominant. Main land uses comprise temporal crops and pasture throughout the years. The watershed showed a natural potential for low surface erosion. When related to usage types, yearly soil loss was also low ( 50 ton.ha1.year1), with more critical scores that reach rates higher than 150 ton.ha1.year1. Soil loss over the years did not provide great distinctions in distribution standards, although it becames rather intensified in some sectors, especially in the center-eastern and southwestern sections of the watershed.

Resumo Este estudo visa analisar o comportamento multitemporal da perda de solo por erosão hídrica laminar na bacia hidrográfica do rio Mourão, localizada na região centro-ocidental do Estado do Paraná Brasil. A predição foi baseada na aplicação da Equação Universal de Perdas de Solo (USLE), com integração dos dados e estimativas realizados em ambiente SIG (Sistema de Informações Geográficas). Os resultados mostram elevada erosividade da chuva média anual (10.000 MJ.mm.ha1.h1.ano1). Os solos apresentam, em geral, média erodibilidade, com exceções do Latossolo Vermelho Distroférrico (classe baixa) e o Argissolo Vermelho Distrófico (classe alta). O fator topográfico atingiu índices elevados (>20), no entanto, predominaram os valores inferiores a 1. Os tipos de usos principais são as lavouras temporárias e pastagem, para todos os anos. A bacia apresentou Potencial Natural a Erosão laminar predominante baixo, quando relacionado aos tipos de usos resultou numa perda de solo anual estimada também baixa ( 50 ton.ha1.ano1), com pontos mais críticos que atingem valores superiores a 150 ton.ha1.ano1. A perda de solo entre os anos não apresentou grandes distinções nos padrões de distribuição, apenas intensificou-se em alguns setores, como nas porções centro-leste e sudoeste da bacia.

Hepatitis B virus genotype E detected in Brazil in an African patient who is a frequent traveler

Genotype E of hepatitis B virus (HBV) has not been described in Brazil and is found mainly in Africa. Genotype A is the most prevalent in Brazil, and genotypes B, C, D, and F have already been reported. We report here an HBV genotype E-infected patient and some characterization of surface (S) protein, DNA polymerase (P) and precore/core (preC/C) coding regions based on the viral genome. The patient is a 31-year-old black man with chronic hepatitis B who was born and raised in Angola. He has been followed by a hepatologist in São Paulo, Brazil, since November 2003, and he is a frequent traveler to Latin America, Africa, and Europe. In 2003, he was diagnosed with HBV infection and started treatment with lamivudine with the later addition of adefovir dipivoxil. No known risk factor was identified. Serologically, he is HBsAg and anti-HBe positive, but HBeAg and anti-HBs negative. DNA sequence analysis of the S/P region confirmed that this patient is infected with genotype E, subtype ayw4. The preC/C region showed G1896A and G1899A mutations but no mutations in the basal core promoter. Nucleotide substitutions common in genotype E were also observed (C1772, T1858 and A1757). Although this is not an autochthonous case and there is no evidence of further spread, the description of this case in Brazil highlights the current risk of viral genotypes spreading with unprecedented speed due to constant travel around the world.