741 research outputs found

    Environmental stratification in the brazilian Cerrado on the yield and fiber quality of cotton genotypes.

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    Environmental stratification studies are important for the plant breeding, since they allow to adequately plan the experimental network. The objective of this work was to identify similar environments for cotton cultivation in the Brazilian Cerrado regarding yield and fiber quality. Nineteen field studies were carried out in a randomized complete block design with twelve genotypes and four replicates. Agronomic (cotton seed yield and fiber percentage) and technological traits (length, micronaire, fiber strength) were evaluated. These results indicate that there are six environments (PVA3, MON, SHE1, SIN, PPA e TRIN) in which the cotton trials should be installed as a matter of priority owing to the phenotypic response pattern obtained for the evaluated traits. The remaining 13 environments are similar to each other for all traits and can be summarized in strategic locations depending on the ease of installation of the trials.Título em português: Estratificação ambiental no Cerrado brasileiro sobre o rendimento e a qualidade da fibra dos genótipos de algodão

    Diversity and population dynamic of Tabanidae (Insecta: Diptera) in the Cerrado-Pantanal ecotone.

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    Tabanid (Diptera) species are associated with the mechanical transmission of several pathogens to both domestic and wild animals around the world. The aim of this study was to evaluate the diversity, abundance, and seasonal dynamic of tabanids in the Cerrado-Pantanal ecotone in Miranda, state of Mato Grosso do Sul, Brazil. Tabanids were collected once a month, from June 2001 to May 2003, for seven consecutive days per collection, using canopy and nzi type traps baited with a chemical attractant (1-octen-3-ol). A total of 6,492 individuals from 39 species and 18 genera was collected, which increases from 25 to 34 the number of tabanid species reported for the studied region. Tabanus occidentalis Linnaeus, 1758 (62.21%) was the most abundant species throughout the collection period, followed by Lepiselaga crassipes (Fabricius, 1805) (7.19%) and Tabanus sorbillans Wiedemann, 1828 (5.68%). The peak of the tabanid population was reached during the rainy season, which is the period of the highest potential risk of mechanical transmission of pathogens by these insects in the studied region

    Bioprospecção de actinobactérias da rizosfera para produção de metabólitos bioativos.

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    Actinobactérias rizosféricas, têm mostrado grande potencial na produção de metabólitos bioativos, sendo o gênero das Streptomyces o mais bem estudado e com melhor potencial para produção destes compostos. Assim, o presente trabalho visou realizar a bioprospecção de actinobactérias rizosféricas e avaliar o potencial de seus metabólitos bioativos no controle de bactérias patogênicas. Foram isoladas linhagens de actinobactérias de plantas sadias de milho, cultivado em diferentes regiões edafoclimáticas do Estado de São Paulo. As linhagens foram avaliadas quanto ao potencial de controle de Bacillus megaterium, Escherichia coli, Klebsiella spp., Pseudomonnas aeruginosa e Sthaphylococcus aureus. Os isolados que se mostraram eficientes em testes de antagonismo foram utilizados em ensaios de antibiose para verificação do potencial do composto bioativo no controle destes patógenos. Foram isolados 60 actinobactérias, identificadas morfologicamente como sendo do gênero Streptomyces. Dentre estas, 31 inibiram pelo menos 1 dos 5 patógenos em testes de antagonismos. Nos ensaios de antibiose, foi verificada a eficiência dos metabólitos de 25 actinobactérias no controle dos patógenos testados

    Birefringence in nonlinear anisotropic dielectric media

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    Light propagation is investigated in the context of local anisotropic nonlinear dielectric media at rest with the dielectric coefficients ϵμν=ϵμν(E,B)\epsilon^\mu{}_\nu = \epsilon^\mu{}_\nu (\vec{E},\vec{B}) and constant μ\mu, in the limit of geometrical optics. Birefringence was examined and the general conditions for its occurrence were presented. A toy model is exhibited, in which uniaxial birefringent media with nonlinear dielectric properties could be driven by external fields in such way that birefringence may be artificially controlled. The effective geometry interpretation is also addressed.Comment: 5 pages, 1 figur

    An Interactive WebGIS Integrating Environmental Susceptibility Mapping in a Self-Burning Waste Pile Using a Multi-Criteria Decision Analysis Approach

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    Mining activities promote resulting wastes, so coal mines are prone to release contaminants to the environment, namely to the soil and water. Therefore, the analysis of this type of risk is crucial in waste pile management. The Sao Pedro da Cova (Porto, Portugal) coal waste pile has been studied in recent years, with several data acquired from 2019-2021 under a research project using distinct methodologies. These results are now combined in a multi-approach method to estimate the environmental impacts of the waste pile and identify the contamination. With the integration of all the data in a Geographical Information System (GIS) environment, and to fulfill a scientific gap, this study aims: (i) to create a susceptibility map of contamination in the areas surrounding the self-burning coal waste pile in Sao Pedro da Cova, using Analytical Hierarchy Process (AHP) and Fuzzy AHP approaches; and (ii) to develop a webGIS application incorporating all the information acquired that can be useful for the residents of Sao Pedro da Cova and also to the decision-making public entities and researchers. The results obtained show that the contamination susceptibility is higher surrounding the abandoned mine, particularly along the waste piles and the corresponding runoff areas, which can be especially sensitive

    Artificial neural networks classify cotton genotypes for fiber length.

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    Fiber length is the main trait that needs to be improved in cotton. However, the presence of genotypes x environments interaction for this trait can hinder the recommendation of genotypes with greater length fibers. The aim of this study was to evaluate the adaptability and stability of the fibers length of cotton genotypes for recommendation to the Midwest and Northeast, using artificial neural networks (ANNs) and Eberhart and Russell method. Seven trials were carried out in the states of Ceará, Rio Grande do Norte, Goiás and Mato Grosso do Sul. Experimental design was a randomized block with four replications. Data were submitted to analysis of adaptability and stability through the Eberhart & Russell and ANNs methodologies. Based on these methods, the genotypes BRS Aroeira, CNPA CNPA 2009 42 and CNPA 2009 27 has better performance in unfavorable, general and favorable environment, respectively, for having fiber length above the overall mean of environments and high phenotypic stability
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