RESUMO O objetivo deste estudo foi descrever comportamentos de riscos para a saúde em adolescentes e verificar as possíveis associações entre estes. Tratou-se de um estudo transversal, realizado na cidade de Teresina/PI, com 540 adolescentes de 14 a 19 anos. O instrumento utilizado para o levantamento de dados foi uma adaptação do questionário do projeto “COMPAC”. Cerca de 35% dos adolescentes relataram assistir televisão por quatro horas, apenas 22% relataram o uso do computador de uma a duas horas, enquanto 60% afirmaram usar o celular por mais de quatro horas durante a semana. O percentual de adolescentes considerados fisicamente inativos foi superior a 35%. Mais de 15% dos adolescentes consumia bebida alcóolica uma a duas vezes e 11% consumia até duas doses por semana. A quantidade de doses diárias de bebidas alcóolicas foi significativamente associada ao tempo assistindo televisão por semana (OR = 2,45; p = 0,040) e no fim de semana (OR = 2,05; p = 0,032). Foi encontrada alta prevalência de adolescentes fisicamente inativos e de tempo despendido em comportamentos sedentários. Além disso, o comportamento sedentário esteve associado ao consumo de bebidas alcoólicas, Assim, é importante repensar o uso da televisão e do uso álcool no cotidiano dos adolescentes.

Abstract The objective of this study was to describe health risk behaviors in adolescents and to verify the possible associations between them. It was a cross-sectional study conducted in Teresina / PI, with 540 adolescents aged 14 to 19 years. The instrument used for data collection was an adaptation of the “COMPAC” project questionnaire. About 35% of teens reported watching television for four hours, only 22% reported using their computer for one to two hours, while 60% reported using their cell phone for more than four hours during the week. The percentage of adolescents considered physically inactive was greater than 35%. More than 15% of adolescents consumed alcoholic beverages one to two times, and 11% consumed up to two doses per week. The amount of daily doses of alcoholic beverages was significantly associated with TV watching time per week (OR = 2.45, p = 0.040) and at the weekend (OR = 2.05, p = 0.032). It was found a high prevalence of physically inactive adolescents and time spent in sedentary behaviors. In addition, sedentary behavior was associated with alcohol consumption. Thus, it is important to rethink television and alcohol use in adolescents’ daily lives.

ABSTRACT. In Amazonia, the main causes of deforestation are systems based on slash-and-burn agriculture. The objective of this work was to evaluate temporal changes in the soil chemical attributes after the vegetation has been slashed and burned in an area of native forest in the Western Amazon. For this study, four hectares of forest in Cruzeiro do Sul, State of Acre, Brazil, was slashed and burned. The soil in the study area was classified as Ultisol (Argissolo Amarelo Distrófico típico). Soil samples were collected over the course of one year, the first one being collected 16 hours after the burn and the others at 30, 60, 90, 150, 210, 270, and 360 days after the burn. The soil surface layers were more sensitive to fire action. Ashes from vegetation burn increased pH values, basic cations, and C values only in the first months, resulting in higher basal saturation values (V%). The practice of slash-and-burn after 12 months resulted in lower values of pH, Ca, Mg, K, and P and higher values of Al and H, as well as saturation by aluminum in the soil, indicating this practice contributes to the reduction of soil fertility.

Resumo Neste trabalho é relatado o processo de elaboração e aplicação de um roteiro de atividades para professores do Ensino médio consistindo de estratégias para o ensino de tópicos de eletricidade utilizando laboratórios reais e virtuais. Quatro estratégias diferentes foram testadas com alunos do terceiro ano do ensino médio com o objetivo de identificar qual seria mais efetiva para ensinar circuitos elétricos e a Lei de Ohm. Cada estratégia foi caracterizada por uma sequência específica de abordagem, tais como aulas expositivas, simulações computacionais ou atividades experimentais, para discutir o tópico. Os resultados indicam que a abordagem experimental, seja virtual ou real, apresenta uma vantagem significativa sobre as aulas teóricas, reforçando a importância da utilização de atividades experimentais na sala de aula.

Abstract We report on the elaboration and application of a guide of activities for High School teachers consisting of strategies to teach topics in electricity using real and virtual laboratories. We tested four different strategies with students in the final year of high school to figure out which would be more effective to teach about electric circuits and Ohm's law. Each strategy was characterized by a specific sequence of approaches, such as lectures, computer simulations or experiments, to present the subject. Our results indicate that the experimental approach, virtual or real, has a significant advantage over lectures, reinforcing the importance of using experimental activities in the classroom.