Química e cidadania : uma abordagem a partir do desenvolvimento de atividades experimentais investigativas

Este trabalho teve por objetivo analisar a contribuição da abordagem investigativa para a resolução de problemas visando o desenvolvimento da cidadania por alunos do primeiro ano do Ensino Médio da rede pública de ensino brasileira, quando envolvidos em atividades experimentais investigativas que versaram sobre situações sociocientíficas controversas relacionadas ao tema “combustíveis”. A coleta de dados se deu por meio da aplicação de um minicurso de quarenta horas para uma turma de oito alunos. A abordagem proposta auxiliou os alunos no processo de tomada de decisão e contribuiu também para o desenvolvimento e aprendizagem de conteúdos conceituais, procedimentais e atitudinais, proporcionando aos mesmos uma visão mais adequada da ciência, ou seja, uma atividade humana em permanente construção

A ambientalização curricular e a formação inicial de professores de química: um estudo de caso brasileiro

O principal objetivo deste trabalho refere-se à investigação do modo como a dimensão ambiental se insere na formação dos estudantes do curso de licenciatura em Química de uma universidade pública brasileira. A temática da pesquisa revela-se importante, pois há a preocupação institucional com a proposta de ambientalização curricular na formação de profissionais, neste caso, professores de Química, que se comprometam continuamente com o estabelecimento das melhores relações possíveis entre sociedade e natureza, contemplando valores e princípios éticos universalmente reconhecidos. Além disto, pretende-se pesquisar a forma como esta dimensão se relaciona com as temáticas científica, tecnológica, econômica e social, tal como se pode observar na proposta concernente ao perfil profissional e habilidades a serem desenvolvidas do licenciando do referido curso

Classical diamagnetism, magnetic interaction energies, and repulsive forces in magnetized plasmas

The Bohr-van Leeuwen theorem is often summarized as saying that there is no classical magnetic susceptibility, in particular no diamagnetism. This is seriously misleading. The theorem assumes position dependent interactions but this is not required by classical physics. Since the work of Darwin in 1920 it has been known that the magnetism due to classical charged point particles can only be described by allowing velocity dependent interactions in the Lagrangian. Legendre transformation to an approximate Hamiltonian can give an estimate of the Darwin diamagnetism for a system of charged point particles. Comparison with experiment, however, requires knowledge of the number of classically behaving electrons in the sample. A new repulsive effective many-body force, which should be relevant in plasmas, is predicted by the Hamiltonian.Comment: added references, revise

Green chemistry in Brazil

The philosophy of green chemistry has been very well received in Latin America's research and development programs. In this review we describe the green chemistry contributions of Brazilian research groups over the last three years.Centro de Investigación y Desarrollo en Ciencias Aplicada

Green chemistry in Brazil

The philosophy of green chemistry has been very well received in Latin America's research and development programs. In this review we describe the green chemistry contributions of Brazilian research groups over the last three years.Centro de Investigación y Desarrollo en Ciencias Aplicada

Impact of safety-related dose reductions or discontinuations on sustained virologic response in HCV-infected patients: Results from the GUARD-C Cohort

BACKGROUND: Despite the introduction of direct-acting antiviral agents for chronic hepatitis C virus (HCV) infection, peginterferon alfa/ribavirin remains relevant in many resource-constrained settings. The non-randomized GUARD-C cohort investigated baseline predictors of safety-related dose reductions or discontinuations (sr-RD) and their impact on sustained virologic response (SVR) in patients receiving peginterferon alfa/ribavirin in routine practice. METHODS: A total of 3181 HCV-mono-infected treatment-naive patients were assigned to 24 or 48 weeks of peginterferon alfa/ribavirin by their physician. Patients were categorized by time-to-first sr-RD (Week 4/12). Detailed analyses of the impact of sr-RD on SVR24 (HCV RNA <50 IU/mL) were conducted in 951 Caucasian, noncirrhotic genotype (G)1 patients assigned to peginterferon alfa-2a/ribavirin for 48 weeks. The probability of SVR24 was identified by a baseline scoring system (range: 0-9 points) on which scores of 5 to 9 and <5 represent high and low probability of SVR24, respectively. RESULTS: SVR24 rates were 46.1% (754/1634), 77.1% (279/362), 68.0% (514/756), and 51.3% (203/396), respectively, in G1, 2, 3, and 4 patients. Overall, 16.9% and 21.8% patients experienced 651 sr-RD for peginterferon alfa and ribavirin, respectively. Among Caucasian noncirrhotic G1 patients: female sex, lower body mass index, pre-existing cardiovascular/pulmonary disease, and low hematological indices were prognostic factors of sr-RD; SVR24 was lower in patients with 651 vs. no sr-RD by Week 4 (37.9% vs. 54.4%; P = 0.0046) and Week 12 (41.7% vs. 55.3%; P = 0.0016); sr-RD by Week 4/12 significantly reduced SVR24 in patients with scores <5 but not 655. CONCLUSIONS: In conclusion, sr-RD to peginterferon alfa-2a/ribavirin significantly impacts on SVR24 rates in treatment-naive G1 noncirrhotic Caucasian patients. Baseline characteristics can help select patients with a high probability of SVR24 and a low probability of sr-RD with peginterferon alfa-2a/ribavirin