Abstract Accidents caused by leaks and/or spills on soils need to be addressed. Natural attenuation, biostimulation and bioaugmentation can be useful bioremediation strategies for decontamination processes in soils of diesel/biodiesel mixtures. The purpose of this study was to evaluate the degradation rate of the different fuels (B0, B20 and B100) in an ultisol under natural attenuation and biostimulation/bioaugmentation during 60 days of incubation in a controlled microcosm simulating a surface spill over soil. The degradation of different diesel/biodiesel mixtures was monitored for up to 60 days by dehydrogenase activity, respirometry by CO2 release, the most probable number of heterotrophic and degrading microorganism and gas chromatography. The bacterial inoculum employed for biostimulation/bioaugmentation strategy consisted of Bacillus megaterium, Bacillus pumilus, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia. The two bioremediation strategies have showed great degradation rates. The natural attenuation was effective for B0 and B20 treatments. The addition of the bacterial consortium and macronutrients contributed to the increased degradation of pure biodiesel in relation to natural attenuation, with higher rates for CO2 release, enzymatic and degrading activity. It is suggested that the bacterial consortium has proven effective for presenting significant values for such parameters until the end of the 60-day incubation period.

Resumo: Este artigo apresenta dois estudos independentes que têm como objetivo investigar como uma ferramenta baseada em mineração de texto e apresentação gráfica multirrepresentacional (SOBEK) pode contribuir no processo de construção de conceitos científicos por estudantes do Ensino Fundamental. Os estudos foram realizados através de pesquisa quasi-experimental com aplicação de pré-teste e pós-teste, utilizando grupos controle não equivalentes. Textos refutacionais de pesquisas já publicadas foram utilizados nas intervenções, assim como testes de performance correspondentes aos textos. Os conceitos abordados foram energia e natureza particulada da matéria. Os estudos foram conduzidos em duas turmas de 9º ano de uma escola municipal no sul do Brasil. Análises estatísticas do desempenho nos testes mostraram melhora significativa dos estudantes que utilizaram o SOBEK como suporte para estudo dos textos. Investigações mais detalhadas são necessárias para identificar a ocorrência e extensão das modificações na estrutura conceitual dos estudantes e sua relação com a estratégia proposta.

Abstract: This work presents two independent studies that aim to investigate how a tool based on text mining and multi-representational graphical presentation (SOBEK) can contribute to the process of constructing scientific concepts from text by elementary school students. The studies were conducted in a quasi-experimental design with application of pre-test and post-tests with non-equivalent control groups. Refutational texts from published researches were used, as well as the corresponding performance tests about each text. The concepts covered are energy and the particulate nature of matter. Performed in a municipal school in Southern Brazil, the studies included two classes of 8th grade students. Statistical analysis of scores performed by students in tests show significant improvements in student's performance that used the SOBEK tool as support for the study of text. More detailed studies are needed to identify the occurrence and extent of possible changes in students´ conceptual structure supported by the proposed approach.

ABSTRACT During composting processes, the degradation of organic waste is accomplished and driven by a succession of microbial populations exhibiting a broad range of functional competencies. A total of 183 bacteria, isolated from a composting process, were evaluated for cellulase activity at different temperatures (37, 50, 60, and 70°C) and pH values. Out of the 22 isolates that showed activity, isolate 380 showed the highest cellulase activity. Its ability to produce cellulase was evaluated in culture medium supplemented with carboxymethyl cellulose, microcrystalline cellulose, wheat straw, and rice husk. The culture medium supplemented with carboxymethyl cellulose induced higher enzyme activity after 6 hours of incubation (0.12 UEA mL-1 min-1). For wheat straw and rice husk, the results were 0.08 UEA mL-1 min-1 for both, while for microcrystalline cellulose, 0.04 UEA mL-1 min-1 were observed. The highest carboxymethyl cellulase activity was observed at 60°C (0.14 UEA mL-1 min-1) for both crude and partially purified enzyme after 30 and 120 min of incubation, respectively. Alkalinization of the medium was observed during cultivation in all substrates. The cellulase had a molecular mass of 20 kDa determined by SDS-Page. Isolate 380 was identified as Bacillus licheniformis. This work provides a basis for further studies on composting optimization.

A técnica da compostagem é um recurso empregado com o objetivo de reciclar resíduos orgânicos domésticos e sanitizar o lodo produzido nas estações de tratamento de efluentes de esgoto (ETE) podendo-se obter um composto com propriedades de fertilizante agrícola e/ou corretor de solos degradados. A alta temperatura atingida pelo sistema deve ser responsável pela redução de micro-organismos patogênicos presentes no início do processo assegurando, desta forma, a qualidade microbiológica do composto sem oferecer riscos de contaminação, conforme preconiza a Resolução 354/2006 do CONAMA. Objetivou-se, com o trabalho, avaliar a influência da temperatura sobre a redução de Escherichia coli, Salmonella sp., ovos de helmintos e vírus entéricos durante o processo de compostagem, além da contagem de bactérias heterotróficas. Foram realizados testes colimétricos, semeaduras em meios de cultivo, testes de visualização de ovos de helmintos e detecção molecular de vírus entéricos. Os resultados indicaram oscilação nas contagens de E. coli e de bactérias heterotróficas, mesmo após a fase termofílica. Por outro lado, não foi detectada a presença de Salmonella sp., vírus entéricos nem de ovos viáveis de helmintos, ao final do processo.

The composting technique is a promising alternative for the treatment of solid organic residues, along with the sludge produced in sewage treatment plants. The final compost might show fertilizer properties, which can be used to recover poor soils. The high temperatures that the composting process can achieve are responsible for the reduction of the pathogenic microbial population, helminth eggs and virus present in the beginning of the process. This behavior assures the microbial quality of the compost according to the 375/2006 Resolution of the CONAMA. The aim of this study was to evaluate the influence of temperature on Escherichia coli, Salmonella sp., helminth egg and enteric virus presence in the final product from a composting process. For this matter colimetric assays were performed together with the seedling of the samples in different culture media, the assay for helminth eggs visualization under the microscope and the identification of enteric virus. The results showed an oscillation on E. coli and heterotrophic bacteria counts, even after the thermophilic phase. On the other hand, Salmonella sp., helminth eggs and enteric virus were not found in the final compost.

A exposição a eventos incontroláveis produz dificuldade na aprendizagem de novos comportamentos. O presente estudo investigou o papel da instrução e da exposição à controlabilidade na reversão dos efeitos da história de incontrolabilidade. No treino, estudantes universitários foram expostos à controlabilidade (grupo CC) ou à incontrolabilidade (grupos IC, ICi, II, IIi). Na "terapia", os grupos CC, IC e ICi foram expostos à controlabilidade, enquanto os grupos II e IIi continuaram expostos à incontrolabilidade. Os grupos ICi e IIi receberam uma instrução de incontrolabilidade/controlabilidade. No teste, todos os grupos foram expostos a controlabilidade. Os participantes expostos apenas à incontrolabilidade (grupos II e IIi) apresentaram maior persistência do responder do que aqueles expostos à "terapia" (grupos IC e ICi), os quais não diferiram dos participantes expostos apenas à controlabilidade (Grupo CC), a despeito da instrução. O procedimento de "terapia", portanto, foi mais efetivo do que a instrução para reverter os efeitos da história de incontrolabilidade.

Pre-exposure to uncontrollable events interferes with subsequent learning of new behaviors. The present study investigated the role of instructions and of the exposure to controllability in reversing the effects of a history of uncontrollability. During training, college students were exposed to controllability (CC Group) or to uncontrollability (IC, ICi, II and Iii groups). During "therapy", the CC, IC and ICi groups were exposed to controllability while the II and IIi groups remained exposed to uncontrollability. An instruction on uncontrollability/controllability was given to the ICi and IIi groups. During testing, all groups were exposed to controllability. The participants exposed only to uncontrollability (II and IIi groups) showed greater response persistence than those exposed to "therapy" (IC and ICi groups) that did not differ from those exposed only to controllability (CC Group). The "therapy" procedure, then, was more effective than instructions in reversing the effects of a history of uncontrollability.

La exposición a eventos incontrolables produce dificultad en el aprendizaje de nuevos comportamientos. El presente estudio investigó el rol de la instrucción y de la exposición a la controlabilidad en la reversión de los efectos de la historia de incontrolabilidad. En el entrenamiento, estudiantes universitarios fueron expuestos a la controlabilidad (grupo CC) o a la incontrolabilidad (grupos IC, ICi, II, IIi). En la "terapia", los grupos CC, IC y ICi fueron expuestos a la controlabilidad, mientras que los grupos II y IIi siguieron expuestos a la incontrolabilidad. Los grupos ICi y IIi recibieron una instrucción de incontrolabilidad/controlabilidad. En el test, todos los grupos fueron expuestos a la controlabilidad. Los participantes expuestos sólo a la incontrolabilidad (grupos II y IIi) presentaron mayor persistencia del responder, comparados a aquellos expuestos a la "terapia" (grupos IC y ICi), los cuales no se distinguieron de los participantes expuestos sólo a la controlabilidad (Grupo CC), pese a la instrucción. El procedimiento de "terapia", por lo tanto, fue más efectivo que la instrucción para revertir los efectos de la historia de incontrolabilidad.