Our data support the hypothesis that WWTPs constitute a potential hot spot for horizontal gene transfer and for selection of antimicrobial resistance genes among aquatic bacteria. Moreover, water discharges represent a possible risk for dissemination of undesirable genetic traits.
The objective of this study was to evaluate, comparatively, the evolution of this degradation of three rock types, two granitoids and a microgabbro which, eventually, could be used as ballast, due to the proximity of the quarries to the design route of a railroad to be built between São Paulo and around Campinas, State of São Paulo, southeastern Brazil. They were tested for alterability in sodium sulfate and ethylene glycol solutions. Based on detailed petrographic analysis, Micro-Deval and Slake Durability Index tests were performed with and without conjugation to the referred alterability tests. The results obtained are punctual, valid and positive for the samples of the rock masses carefully selected and described, considering the different characteristics of the granitoids belonging to the Morungaba and Cantareira Complexes. In the case of basic rock, the microgabbro, should not be used as ballast in the studied tropical climate area, since the exposed fragments that make up the ballast are intensely affected by chemical weathering (notably reactions accelerated by water and temperature), which culminate in the decomposition of primary minerals and, consequently, in the faster physical-mechanical degradation of this rock. In practice, more frequent periodic maintenance and higher costs.
Considerando a possibilidade de implantação do Trem de Alta Velocidade, previsto em projeto governamental que ligará as cidades de Campinas e Rio de Janeiro, o presente trabalho trata da seleção do material pétreo disponível na região de Campinas, que possua alta qualidade para o emprego como lastro da ferrovia e obras de concreto. Com este objetivo foram confrontados dados petrográficos e resultados de ensaios físico-mecânicos de cinco variedades de rochas cristalinas (micro-gabro, gnaisse e granitos) muito utilizadas como agregado na construção civil, mas ainda não suficientemente estudadas para lastro ferroviário. Foram encontrados valores de resistências inferiores ou próximos aos limites normatizados para esta finalidade, restringindo a utilização de alguns dos materiais estudados. É importante frisar que materiais pétreos utilizados como agregado no lastro de ferrovias ficam sujeitos à exposição constante das intempéries, fazendo com que estudos envolvendo alterabilidade sejam tão importantes quanto os de caracterização geomecânica, levando-se em conta as condições tropicais típicas da região
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