Caffeine as a contaminant of periphyton: ecological changes and impacts on primary producers.

Every day, tons of caffeine is consumed by humans in beverages, medications or supplements, and a significant amount of this stimulant is released in domestic sewage. Once in aquatic environments caffeine interacts directly with the periphytic community, which is responsible for a significant part of primary production in aquatic ecosystems. However, the effects of exposure to caffeine are mostly unknown for both the periphyton and their predators. Aiming to comprehend the interaction between caffeine and the periphytic community, ecotoxicological experiments were performed by exposing a periphytic biofilm cultivated in the laboratory to different concentrations of caffeine, following concentrations found in domestic sewers. The impact of exposure to this contaminant was observed on the structure of the community through taxonomic evaluation, as well a set of physiological variables linked to primary production. After exposure to the highest caffeine concentration (300 µg L-1), the density of the genus Scenedesmus was severely affected, leading to an increase in cyanobacteria and diatoms. Both richness and diversity decreased after exposure, and there was lower photosynthetic activity, with light saturation point changing from 186 µmol m-2 s-1 in the control treatment to 108 µmol m-2 s-1 after exposure. Caffeine accumulation within the biofilm was also observed during the first 24 h, in the concentration of 0.14 µg /cm².

A Relação entre as Representações acerca das Figuras Parentais e as Competências Sociais em Crianças Maltratadas e não Maltratadas / Relationship between Mental Representations of Parents and Social Competence of Abused and Nonabused Children

RESUMO Assumindo a centralidade das representações acerca das figuras parentais na trajetória desenvolvimental, este estudo teve como objetivo analisar a relação destas representações com as competências sociais de crianças maltratadas e não maltratadas. Participaram, nesta investigação, 62 crianças em idade escolar (22 maltratadas e 40 não maltratadas). As representações acerca das figuras parentais foram avaliadas com a Entrevista de Avaliação das Representações acerca das Figuras Parentais e as competências sociais com a adaptação portuguesa da Social Skills Rating System - Form for Teachers. Nas crianças maltratadas, não se verifica a associação entre as representações das figuras parentais e as competências sociais, observada em amostras normativas. Os resultados sugerem que os dois grupos atribuem significados distintos aos comportamentos parentais.

ABSTRACT Considering the importance of mental representations of parental figures in the developmental trajectory of children, this study aimed to analyze the relationship of these representations with the social competence of abused and nonabused children. A total of 62 school-aged children participated in this study (22 maltreated and 40 nonmaltreated). The mental representations of the children were assessed with the Children Representations about Parental Figures Interview, while social competence was assessed with means of the Portuguese version of the Social Skills Rating System - form for teachers. The association between representations of parental figures and social competence observed in normative samples does not exist in abused children. These results suggest that abused and nonabused children attribute different meanings to their parents' behavior.