965 research outputs found
Benthic macro-invertebrates as indicators of ecological fragility of small rivers ('igarapés') in a bauxite mining region of Brazilian Amazonia
Benthic macroinvertebrate communities were studied in the igarapés Saracá, Caranã and Água Fria near Porto Trombetas, Municipality of Oriximiná, State of Pará, Brazil (1°25' to 1°35'S and 56°15' to 56°W). The main objective was to investigate the potential use of the benthic macroinvertebrates community as indicators of the ecological fragility of the igarapés located in an area of the Amazon basin influenced by bauxite mining. These aquatic ecosystems have low pH (< 4.5); low electrical conductivity (< 90 µS cm-1); low or undetectable total alkalinity; low nutrient concentrations in the sediment, which implies low primary productivity; low species richness; low secondary productivity; and low rates of organic matter decomposition. The benthic macroinvertebrates utilize mainly allochthonous organic matter. Some areas of the ecosystems investigated have been modified by bauxite tailings (especially in their sediment granulometry), by a dam formed by railroad construction (which altered the hydrodynamics and eliminated the terra firma vegetation), and by accidental discharges of various minerals from the railroad traffic and bauxite mining. These factors have drastically modified the local benthic macroinvertebrate communities. The value of benthic macroinvertebrates as indicators of ecological fragility, the health of the ecosystem investigated, and water quality is evaluated
Estimativa do volume de água pluvial que pode ser reutilizada na suinocultura: um estudo de caso
The West of Paraná has risen in the context of national agribusiness, where swine production is an increasing and highly important activity. As a result of this activity, there has been an extensive use of natural resources, resulting in environmental impacts mainly due to the high demand for water, which is used both for consumption and for cleaning the stalls. Based on this context, this study aimed to estimate the volume of rainwater that can be reused for the cleaning of installations. The study was carried out in a covered building for raising pigs measuring 1,200 m2, located in the district of Iguiporã, in Marechal Cândido Rondon (Paraná, Brazil). The volume of water was estimated through data related to average precipitation, covering area of the building and sizing calculations of the volume of the cisterns needed for implementation in the property according to ABNT standards (NBR 15527). The results showed that the implementation of the system could represent savings of approximately 77,65% of the water used for cleaning. This demonstrates that rainwater collection decreases the impact on the use of treated water and contributes to the conservation of this important natural resource.O Oeste do Paraná tem se destacado no contexto do agronegócio nacional, onde a suinocultura apresenta-se como uma atividade de grande crescimento e importância. Em conseqüência desta atividade, tem-se observado grande uso dos recursos naturais e impactos ao meio ambiente, principalmente devido à alta demanda por água, a qual é utilizada tanto para consumo, quanto para a limpeza das baias. Frente ao exposto, este trabalho teve como objetivo estimar o volume de água de precipitação pluviométrica que pode ser reaproveitada na limpeza das instalações. O estudo foi desenvolvido em uma granja coberta de 1200 m2, localizada no distrito de Iguiporã no município de Marechal Cândido Rondon – PR. Foi estimado o volume de água por meio de dados de precipitação pluvial média, área de cobertura da granja e cálculos do dimensionamento do volume da cisterna necessária para a implantação na propriedade segundo NBR 15527 da ABNT. Os resultados evidenciaram que com a implantação do sistema seria possível uma economia de aproximadamente 77,65 % da água consumida para limpeza. Demonstrando que a coleta de águas pluviais diminui o impacto sobre o uso de água tratada e contribui para a preservação desse importante recurso natural
Targeted Chromosomal Insertion of Large DNA into the Human Genome by a Fiber-Modified High-Capacity Adenovirus-Based Vector System
A prominent goal in gene therapy research concerns the development of gene transfer vehicles that can integrate exogenous DNA at specific chromosomal loci to prevent insertional oncogenesis and provide for long-term transgene expression. Adenovirus (Ad) vectors arguably represent the most efficient delivery systems of episomal DNA into eukaryotic cell nuclei. The most advanced recombinant Ads lack all adenoviral genes. This renders these so-called high-capacity (hc) Ad vectors less cytotoxic/immunogenic than those only deleted in early regions and creates space for the insertion of large/multiple transgenes. The versatility of hcAd vectors is been increased by capsid modifications to alter their tropism and by the incorporation into their genomes of sequences promoting chromosomal insertion of exogenous DNA. Adeno-associated virus (AAV) can insert its genome into a specific human locus designated AAVS1. Trans- and cis-acting elements needed for this reaction are the AAV Rep78/68 proteins and Rep78/68-binding sequences, respectively. Here, we describe the generation, characterization and testing of fiber-modified dual hcAd/AAV hybrid vectors (dHVs) containing both these elements. Due to the inhibitory effects of Rep78/68 on Ad-dependent DNA replication, we deployed a recombinase-inducible gene switch to repress Rep68 synthesis during vector rescue and propagation. Flow cytometric analyses revealed that rep68-positive dHVs can be produced similarly well as rep68-negative control vectors. Western blot experiments and immunofluorescence microscopy analyses demonstrated transfer of recombinase-dependent rep68 genes into target cells. Studies in HeLa cells and in the dystrophin-deficient myoblasts from a Duchenne muscular dystrophy (DMD) patient showed that induction of Rep68 synthesis in cells transduced with fiber-modified and rep68-positive dHVs leads to increased stable transduction levels and AAVS1-targeted integration of vector DNA. These results warrant further investigation especially considering the paucity of vector systems allowing permanent phenotypic correction of patient-own cell types with large DNA (e.g. recombinant full-length DMD genes)
Uma proposta metodológica para o ensino dos conceitos de pressão e diferença de pressão
Rapid identification of capybara (Hydrochaeris hydrochaeris) using allele-specific PCR
Leaf litter as a possible food source for chironomids (Diptera) in Brazilian and Portuguese headwater streams
Impacto da adubação orgânica sobre a incidência de tripes em cebola.
Analisou-se a relação entre adubação orgânica e a incidência de Thrips tabaci Lind. em cebola (Allium cepa L), na EE de Ituporanga,entre agosto e dezembro de 1998. Os tratamentos foram determinados de acordo com a necessidade de N para a cultura pela análise de solo. Empregou-se como fonte orgânica diversos adubos fornecendo 75 Kg/ha de N (esterco suíno; adubo Barriga Verde proveniente de esterco de aves; composto orgânico; esterco de peru; húmus); 37,5 Kg/ha de N (metade da dose normal com esterco de suíno); as testemunhas foram adubação mineral fornecendo 30-120-60 kg/ha de N-P2O5-K2O e o dobro da dose (60-240-120 kg/ha de N-P2O5-K2O); e testemunha sem adubação. Nenhum tratamento apresentou incidência de T. tabaci superior à testemunha sem adubo. A adubação mineral em relação à orgânica não favoreceu significativamente a incidência de T. tabaci . O processo de conversão do manejo do solo da área experimental de convencional para orgânico pode ter
favorecido a infestação similar do inseto entre tratamentos. No período de maior incidência de T. tabaci, a relação com nutrientes foi descrita por um modelo envolvendo K/Zn, B e N de maneira positiva. A correlação entre nutrientes e T. tabaci não foi linear na maioria
das avaliações. A adubação orgânica pode substituir a adubação mineral na cultura da cebola, pois foi possível atingir níveis de produtividade similares para ambos tratamentos
Temporal shoreline series analysis using GNSS
In recent decades, Boa Viagem beach located in the city of Recife-PE and Piedade in Jaboatão dos Guararapes-PE (Brazil) has seen urbanization near the coastline causing changes in social, economic and morphological aspects, where coastal erosion problems are observed. This study uses GNSS (global navigation satellite system) shoreline monitoring approach, which is quicker, and provides continuously updatable data at cm-level accuracy to analyze and determine temporal positional shifts of the shoreline as well as annual average rates through EPR (end point rate). To achieve this, kinematic GNSS survey data for the years 2007, 2009, 2010 and 2012 were used. The results show sectorial trends over the years, with the highest annual retreat rate of 8.16 m /year occurring during the period 2007-2009. Variety of different patterns over the shoreline were also observed. These findings could be essential for decision making in coastal environments
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