Composição molecular e origem paleobotânica de âmbares da bacia do Araripe, Formação Santana

The terpenoid composition of seven amber samples from Araripe Basin (Santana Formation, Crato Member) has been analyzed by gas chromatography-mass spectrometry to determine their botanical origin. The diterpenoids, which have been identified in the fossil resin extracts are derived primarily from the abietane class, e.g., dehydroabietane, 4-epidehydroabietol, 16,17,18-trisnorabieta-8,11,13-triene, 7-oxo-16,17,19-trisnorabieta-8,11,13-trieno, dehydroabietic acid, ferruginol, hinokiol and hinokione. Their composition is certainly typical for conifers, and angiosperms can be excluded as the botanical source, as no triterpene was identified. The terpenoid characteristics strongly support a relationship to the Araucariaceae or Podocarpaceae families. In addition, the fossil record of the embedding sediments (pollen and fossil leaves) also supports the proposal of these paleobotanical origins for the ambers.

Remoção de Pb2+ e Cr3+ em solução por zeólitas naturais associadas a rochas eruptivas da formação serra geral, bacia sedimentar do Paraná

The capacity of natural zeolites and its host rock (dacite) to remove Pb2+ and Cr3+ from aqueous solutions has been investigated. Results showed that both samples prefer to remove Pb2+ instead of Cr3+. Almost 100% of Pb2+ was removed from solutions with concentration until 50 mg L-1 and 100 mg L-1 of this metal, respectively by dacite and zeolite. The equilibrium of metals adsorption process was reached during the first 30 min by both materials. Na+ can be used to recover Pb2+, but not to remove Cr3+ from the treated samples. The Sips model showed a good fit for experimental data of this study.

Implantação das diretrizes curriculares nacionais para formação de professores de química em uma instituição federal de ensino superior: desafios e perspectivas

The Curricular Proposals for Chemistry Teaching Courses aim at producing a reflexive-researcher teacher, who will be able to deal with cross-disciplinary subjects. The challenge faced by the majority of the federal universities, in implementing these guidelines, is to attain these objectives inside their departmental structure. We present here the formulation of the Chemistry Teaching Course Pedagogic Project from Federal University of Pelotas concerning on the CNE/CP 1/2002 and 2/2002 Resolutions. We discuss the impact of these Proposals, the difficulties faced and the new perspectives of organization inside of these institutions, which resulted in new spaces with cross-disciplinary and cross-departmental orientation.

Produção científica e formação de recursos humanos na área de bioquímica em instituições federais do Rio Grande do Sul: fomento estadual

Brazilian scientific production in Biochemistry is growing impressively fast, and Rio Grande do Sul is outstanding in that context. This study aims to outline the state's scientific research profile, given its prominent position in the national scenario. Hence, researchers, laboratories, development of human resources and investments by Foundation for the Support to Research in the State of Rio Grande do Sul (FAPERGS) were identified and mapped. We observed that amount of financial support by FAPERGS decreases in last years. Therefore, there is the necessity to reestablish some of FAPERGS's programs, as well as to increase financial support to Biochemistry departments.

Em busca da conservação ambiental: a contribuição da percepção ambiental para a formação e atuação dos profissionais da Química

Planet transformations caused by human intervention in the last 200 years are largely due to chemical impact. Therefore, this study aimed to identify and analyze the environmental perception of undergraduate students and lecturers in the Chemistry course of the Federal University of Lavras, accounting for the topics "Environmental Definition" and "Relationship between Chemistry and Environment". Two thematic axes for discussion were proposed using theories of Social Representation and Environmental Complexity, with the aim of stimulating the conservationist reasoning and actions. Such axes were proposed to give support to the education of chemists at the undergraduate level.

Sistema RTP: uma técnica poderosa para o monitoramento da formação de nanotubos de carbono durante o processo por deposição de vapor químico

In this work, a TPR (Temperature Programmed Reduction) system is used as a powerful tool to monitor carbon nanotubes production during CVD (Chemical Vapour Deposition), The experiments were carried out using catalyst precursors based on Fe-Mo supported on Al2O3 and methane as carbon source. As methane reacts on the Fe metal surface, carbon is deposited and H2 is produced. TPR is very sensitive to the presence of H2 and affords information on the temperature where catalyst is active to form different forms of carbon, the reaction kinetics, the catalyst deactivation and carbon yields.

A formação inicial em química baseada em conceitos representados por meio de modelos mentais

The current legislation determines that the chemist must have a solid comprehension about chemical concepts. Literature presents the concept of mental model, which is determinant to the learning of phenomena and concepts. This paper presents some mental models that students of the Chemistry course at UFSCar have about chemical concepts. A lot of incoherence was observed in student's mental models, which is an evidence that there are problems in the learning of chemistry education.

Estudo de casos na formação de professores de química

Case studies were used as teaching methodology in Chemistry teacher education. The reffered methodology consists of teaching principles of Physical Chemistry associated to biodiesel theme in an undergraduate chemistry course with pre-service teachers, who are temporary teachers in high schools in Fortaleza, Ceará, Brazil. The results showed that the methodology was well accepted by the pre-service teachers. The concepts related to Chemistry, by means of multidisciplinary science, technological and social approaches make it able to overcome and improve the present situation in public schools and provided the learning of the chemistry concepts by high school students.

Resposta antioxidante, formação de fitoquelatinas e composição de pigmentos fotoprotetores em Brachiaria decumbens Stapf submetida à contaminação com Cd e Zn

In order to evaluate the response of Brachiaria decumbens Stapf to Cd and Zn, plants were hydroponically exposed to 50 and 100 mmol L-1 of Cd and 500 and 2000 mmol L-1 of Zn. Metal content of shoots and roots was determined, as well as alterations in photosynthetic and photoprotective pigments, antioxidant metabolites and phytochelatin synthesis. Plants concentrated elevated levels of Cd and Zn, especially in roots. Zinc exposure negatively affected chlorophyll and β-carotene content, whereas the highest dose of Cd reduced VAZ cycle pigments and tocopherol levels in plant shoots. Cadmium was the maximum inducer of the phytochelatin synthesis pathway.

Formação docente no ensino superior de Química: contribuições dos programas de aperfeiçoamento de ensino

The literature on the challenges of teacher education in undergraduate chemistry teaching is limited. In the present study, the application of didactic proposals elaborated by two authors of this paper, graduate students and teaching assistants of the teaching improvement program at University of São Paulo, was investigated in terms of their contribution to the teaching assistants' education and undergraduate students' receptivity toward them. Such proposals were based on the jigsaw cooperative learning strategy and applied in two undergraduate courses. The results indicate students' good receptivity and suggest their importance to teaching assistants' education.

Percepção dos pós-graduandos em química da Universidade Federal de Minas Gerais sobre a própria formação docente

The pedagogic training of university professors has been overlooked in institutions of higher education. In the second semester of 2009, students of the Graduate Chemistry Program at the Federal University of Minas Gerais participated in an investigation that aimed to evaluate the students' perceptions of their own training to become professors. It was found that a large number of students felt prepared to teach at institutions of higher education, despite their lack of experience at this education level. A significant point in this work was the finding that most students do not acknowledge the need of associating the teaching practice with teaching-learning theories, but instead consider the knowledge of scientific content important.

Formação de carbamato de etila em aguardentes recém-destiladas: proposta para seu controle

The commercial sugar cane spits redistillation decreased up to 92,5% their ethyl carbamate (EC) original content. Quantitative analysis of EC in 15 samples of sugar cane spirit (alembic and column), fresh distilled and collected in situ demonstrated that the urethane is formed mostly after distillation. The average time to achieve the complete EC formation is independent of the diffuse light presence and of the distillation apparatus used. The k obs for urethane formation at 25 ºC was calculate as (3,3 ± 0,5) x 10-5/s and the activation parameters are: ΔH‡ 34 kcal/mol; ΔS‡ - 69 cal/mol K; and ΔG‡ 54 kcal/mol.

Atividade discursiva na formação de professores de química: a construção do diálogo coletivo

This research was conducted in a research network in teaching science/chemistry, as an alternative for initial and continuing teacher formation. The network is composed by teachers in initial formation, teacher trainers and teachers of basic education of the various areas of science. Assuming the socio-historical perspective, the discourse coming from the social interaction between the collective of teachers, was the object of study. We present an analysis of the interactions of the speech and reflections about the appropriation of scientific/chemical as a social practice mediated by language supplement our results.

A formação dos docentes de química: uma perspectiva multivariada aplicada à rede pública de ensino médio de Goiás

This paper presents a multivariate statistical analysis as a valuable tool for educational management applied to public high school chemistry teacher formation. From 2003 to 2007, a decrease of 10% in the number of public high schools was seen, as well as a reduction of 7% in the number of teachers. Contrarily, there was an increase in the number of university graduate teachers. Principal Component Analyses reveal that in 2003, most chemistry teachers were not university graduates. In 2007, eight Regional Offices of Education reported teachers holding academic degrees, qualifying them as chemistry teacher in the school system

Diferentes olhares acerca dos conhecimentos necessários na formação inicial do professor de Química

This study investigated different understandings about the educational needs of a professor of Chemistry, related to "know" and "know-how". It was verified the convergence and divergence of perceptions of high school students from that point to literature and education legislation. The research was conducted in five states in northern Brazil. The results show the little dialogue between training institutions and secondary schools, since the different understandings about the training needs go in opposite directions.