How does the Taquari river influence in the Cladoceran assemblages in three oxbow lakes? / Qual a influência do rio Taquari nas assembleias de Cladocera em três lagoas marginais?

This study examined the cladoceran assemblages in three oxbow lakes of the Taquari River floodplain, near the transition between the plateau and the plain. We sought to answer the following questions: does the Taquari River function as a geographical barrier or dispersal corridor for Cladocera? Can different degrees of connection induce different structures in the assemblages in each lake? Cladocerans and limnological variables were sampled every other month for one year. Forty-one species were recorded, four of which were common to all the lakes. Our results indicated that the different degrees of connection between the river and the oxbow lakes favoured environmental heterogeneity and diversification in the cladoceran assemblages. The greatest dissimilarity between the two lakes connected with the river indicates that in this case the river functions better as a barrier than a dispersal corridor.

Assembleias de cladóceros foram avaliadas em três lagoas marginais ao rio Taquari, próximo à transição entre planalto e planície. As seguintes questões foram investigadas: O rio Taquari funciona como barreira ou corredor de dispersão para Cladocera? O grau de conexão induz a diferentes estruturas nas assembleias de cada lagoa? Cladocera e variáveis limnológicas foram amostradas a cada dois dias durante um ano. Foram registradas 41 espécies, apenas 4 comuns em todas as lagoas. Nossos resultados apontam que diferentes graus de conexão entre rio e lagoas favorecem a heterogeneidade ambiental e a diversificação das assembleias de cladóceros. A maior dissimilaridade entre as duas lagoas conectadas com o rio indica que, neste caso, o rio funciona melhor como barreira do que como corredor de dispersão.

How does the Taquari River influence in the cladoceran assemblages in three oxbow lakes?

This study examined the cladoceran assemblages in three oxbow lakes of the Taquari River floodplain, near the transition between the plateau and the plain. We sought to answer the following questions: does the Taquari River function as a geographical barrier or dispersal corridor for Cladocera? Can different degrees of connection induce different structures in the assemblages in each lake? Cladocerans and limnological variables were sampled every other month for one year. Forty-one species were recorded, four of which were common to all the lakes. Our results indicated that the different degrees of connection between the river and the oxbow lakes favoured environmental heterogeneity and diversification in the cladoceran assemblages. The greatest dissimilarity between the two lakes connected with the river indicates that in this case the river functions better as a barrier than a dispersal corridor.

Proficiency testing for the determination of pesticides in mango pulp: a view of the employed chromatographic techniques and the evaluation of laboratories' performance.

The proficiency testing for determination of pesticides residues in mango pulp was the third work of the partnership established by INMETRO and INCQS/Fiocruz. Three mango pulp samples were sent to each participant laboratory, two being spiked with the pesticides and one exempt of pesticides. The added pesticides were: deltamethrin, ethion, fenitrothion, malathion, and permethrin. The evaluation of the results of the homogeneity and the stability tests, as well as the determination of the assigned value was made in agreement with ISO GUIDE 35 and ISO 13528, assuming the samples were considered homogeneous and stable for the studied period. The assigned values and the standard deviation for proficiency evaluation was calculated using the robust algorithm, according to ISO 13528, and the evaluation of the results was carried through in accordance with ABNT ISO/IEC Guide 43-1. The z-score graphs and confidence ellipse was also used in the evaluation of the results. In the evaluation carried through from the values of the z-scores, 71% of the reported results were considered satisfactory based on the results found for this index. The evaluation of the analytical viability for the determination of each pesticide and of the analytical capacity of the participant laboratories was carried through. A summarized view of the chromatographic techniques and of preparation of sample used by the participant laboratories was also carried through in this work.