RESUMO

The inadequate disposal of solid waste, a common practice in developing countries, can represent an important pollution source since the closure of these deposits typically does not include the adoption of monitoring, isolation, or remediation techniques. Even so, several disposal areas are abandoned, without performing long-term monitoring in order to evaluate the depletion of contaminants' concentrations. This research aimed at comparing current and historical physicochemical data of water resources surrounding a non-sanitary landfill situated in a Guarani Aquifer recharge zone. The primary objective was to recognize whether significant changes in contaminants concentrations occurred, as well as if the area still poses a significant threat to the environment, 20 years after ending disposing activities. Samples from eight monitoring wells and three surface water points (upstream and downstream to the deposit) were evaluated in the periods of 1996-1997 and 2016-2019. The parameters pH, electrical conductivity (EC), alkalinity, chemical oxygen demand (COD), oxidation-reduction potential (ORP), chloride, nitrate, iron, manganese, calcium, and magnesium were investigated. Contamination has been detected in the landfill surroundings since the ending of the waste disposal (1996-1997), even though its intensity reduced within short distances from the waste mass. Nevertheless, no statistical variation occurred in 20 years' time considering COD, chloride, calcium, magnesium, and ORP. Moreover, increases of EC, pH, alkalinity, iron, and manganese concentrations were observed for the years of 2016-2019. The results indicate that the evaluated contaminants do not suffer depletion in the surroundings of non-sanitary landfills in sandy aquifers, considering a time span of 20 years. This study also suggests that those areas need to be adequately remediated to permit other future land uses.

Assuntos

RESUMO

This study presents an assessment for long-term use of the apical aortic blood pump (AABP), focusing on wear reduction in the bearing system. AABP is a centrifugal left ventricle assist device initially developed for bridge to transplant application. To analyze AABP performance in long-term applications, a durability test was performed. This test indicated that wear in the lower bearing pivot causes device failure in long-term. A wear test in the bearing system was conducted to demonstrate the correlation of the load in the bearing system with wear. Results from the wear test showed a direct correlation between load and wear at the lower bearing pivot. In order to reduce load, thus reducing wear, a new stator topology has been proposed. In this topology, a radial stator would replace the axial stator previously used. Another durability test with the new stator has accounted twice the time without failure when compared with the original model.

Assuntos

RESUMO

The dynamics of the bird community in a small forest fragment was evaluated along seven years in relation to changes in the surrounding landscape. The study area is an Araucaria forest fragment in Southern Brazil (state of Paraná). The sampling period covered the years 1988 through 1994 and the mark-release-recapture method was utilized. The landscape analysis was based on Landsat TM images, and changes in exotic tree plantations, native forest, open areas (agriculture, pasture, bare soil, and abandoned field), and "capoeira"(native vegetation < 2 m) were quantified. The relationship between landscape changes and changes in abundance diversity of forest birds, open-area birds, forest-edge birds, and bamboo specialists was evaluated. Richness estimates were run for each year studied. The richness recorded in the study area comprised 96 species. The richness estimates were 114, 118 and 110 species for Chao 1, Jackknife 1 and Bootstrap, respectively. The bird community varied in species richness, abundance and diversity from year to year. As for species diversity, 1991, 1993 and 1994 were significantly different from the other years. Changes in the landscape contributed to the increase in abundance and richness for the groups of forest, open-area and bamboo-specialist species. An important factor discussed was the effect of the flowering of "taquara" (Poaceae), which contributed significantly to increasing richness of bamboo seed eaters, mainly in 1992 and 1993. In general, the results showed that landscape changes affected the dynamics and structure of the bird community of this forest fragment over time, and proved to have an important role in conservation of the avian community in areas of intensive forestry and agricultural activities.(AU)

Este estudo avaliou a dinâmica da comunidade de aves em um fragmento florestal ao longo de sete anos e correlacionou às mudanças ocorridas na paisagem circundante. A área de estudo localiza-se na Região Sul do Brasil (Estado do Paraná) e a vegetação está representada por Floresta Ombrófila Mista. O período de amostragem ocorreu entre os anos de 1988 a 1994 e o método utilizado foi captura-marcação e recaptura. Para análise da mudança no uso e cobertura da paisagem foram utilizadas imagens Landsat TM e um sistema de informação geográfico. Quatro classes foram usadas, sendo: plantios com espécies exóticas, floresta nativa, capoeiras (vegetação nativa < 2 m de altura) e áreas abertas (campo abandonado, pastagens, área agrícola e solo exposto). Foi analisada a relação entre as mudanças na paisagem e as mudanças na abundância e diversidade de aves de floresta, de área aberta, de borda e especialistas de bambu. Foram calculadas as estimativas de riqueza para cada ano estudado. A riqueza registrada na área de estudo foi de 96 espécies e as estimativas foram 114, 118 e 110 espécies para Chao 1, Jackknife 1 e Bootstrap, respectivamente. A comunidade de aves variou em abundância, riqueza e diversidade entre os anos estudados. Considerando a diversidade de espécies, os valores observados em 1991, 1993 e 1994 foram significativamente diferentes. As modificações na paisagem também contribuíram para o aumento da abundância e riqueza de espécies dos grupos: floresta, área aberta e especialistas de bambu. Um fator importante discutido foi o efeito da floração da taquara (Poaceae), que contribuiu para o aumento significativo da riqueza de aves especializadas em comer sementes de bambu, principalmente em 1992 e 1993. Em geral, observou-se que as modificações na paisagem afetaram a dinâmica e estrutura da comunidade de aves do fragmento florestal ao longo do tempo, evidenciando que até mesmo um fragmento pequeno pode ter um papel importante na conservação da avifauna em áreas de intensa atividade florestal e agrícola.(AU)

Assuntos

RESUMO

The dynamics of the bird community in a small forest fragment was evaluated along seven years in relation to changes in the surrounding landscape. The study area is an Araucaria forest fragment in Southern Brazil (state of Paraná). The sampling period covered the years 1988 through 1994 and the mark-release-recapture method was utilized. The landscape analysis was based on Landsat TM images, and changes in exotic tree plantations, native forest, open areas (agriculture, pasture, bare soil, and abandoned field), and "capoeira"(native vegetation < 2 m) were quantified. The relationship between landscape changes and changes in abundance diversity of forest birds, open-area birds, forest-edge birds, and bamboo specialists was evaluated. Richness estimates were run for each year studied. The richness recorded in the study area comprised 96 species. The richness estimates were 114, 118 and 110 species for Chao 1, Jackknife 1 and Bootstrap, respectively. The bird community varied in species richness, abundance and diversity from year to year. As for species diversity, 1991, 1993 and 1994 were significantly different from the other years. Changes in the landscape contributed to the increase in abundance and richness for the groups of forest, open-area and bamboo-specialist species. An important factor discussed was the effect of the flowering of "taquara" (Poaceae), which contributed significantly to increasing richness of bamboo seed eaters, mainly in 1992 and 1993. In general, the results showed that landscape changes affected the dynamics and structure of the bird community of this forest fragment over time, and proved to have an important role in conservation of the avian community in areas of intensive forestry and agricultural activities.

Este estudo avaliou a dinâmica da comunidade de aves em um fragmento florestal ao longo de sete anos e correlacionou às mudanças ocorridas na paisagem circundante. A área de estudo localiza-se na Região Sul do Brasil (Estado do Paraná) e a vegetação está representada por Floresta Ombrófila Mista. O período de amostragem ocorreu entre os anos de 1988 a 1994 e o método utilizado foi captura-marcação e recaptura. Para análise da mudança no uso e cobertura da paisagem foram utilizadas imagens Landsat TM e um sistema de informação geográfico. Quatro classes foram usadas, sendo: plantios com espécies exóticas, floresta nativa, capoeiras (vegetação nativa < 2 m de altura) e áreas abertas (campo abandonado, pastagens, área agrícola e solo exposto). Foi analisada a relação entre as mudanças na paisagem e as mudanças na abundância e diversidade de aves de floresta, de área aberta, de borda e especialistas de bambu. Foram calculadas as estimativas de riqueza para cada ano estudado. A riqueza registrada na área de estudo foi de 96 espécies e as estimativas foram 114, 118 e 110 espécies para Chao 1, Jackknife 1 e Bootstrap, respectivamente. A comunidade de aves variou em abundância, riqueza e diversidade entre os anos estudados. Considerando a diversidade de espécies, os valores observados em 1991, 1993 e 1994 foram significativamente diferentes. As modificações na paisagem também contribuíram para o aumento da abundância e riqueza de espécies dos grupos: floresta, área aberta e especialistas de bambu. Um fator importante discutido foi o efeito da floração da taquara (Poaceae), que contribuiu para o aumento significativo da riqueza de aves especializadas em comer sementes de bambu, principalmente em 1992 e 1993. Em geral, observou-se que as modificações na paisagem afetaram a dinâmica e estrutura da comunidade de aves do fragmento florestal ao longo do tempo, evidenciando que até mesmo um fragmento pequeno pode ter um papel importante na conservação da avifauna em áreas de intensa atividade florestal e agrícola.

Assuntos