A pesquisa sobre o ensino da relatividade especial e geral: implicações para a prática docente

Em nosso estudo, investigamos as contribuições das pesquisas sobre o Ensino da Teoria da Relatividade Especial e Geral (TREG) e suas implicações para a prática docente. Para tanto, revisamos atas de 03 congressos científicos realizados no Brasil. Mapeamos 44 estudos, os quais foram categorizados de acordo com seus propósitos. Identificamos uma grande quantidade de produções, com foco na análise de conteúdos em livros, na formação de conceitos e na implementação de propostas didáticas, o que permite-nos inferir que, a procura por alternativas para que o ensino da TREG seja realmente efetivado se faz necessária e o aumento de investigações no ambiente escolar parece o caminho mais acertado. Há, também, uma necessidade de investirmos esforços na formação inicial dos professores, para que eles sintam-se seguros para abordar a TREG, quando estiverem em atividade docente.

Aspectos quânticos e clássicos da instabilidade de campos fundamentais em espaços-tempos astrofísicos

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

O grupo de estudos e discussão como subsídio ao desenvolvimento de interações discursivas entre professores de física sobre a temática teoria da relatividade

Based on the assumption that the exchange of knowledge can support a process of self-organized interactions of the involved in the process, we present the results of a study about how happen the dialogue between physics teachers involved in a group of study of Modern and Contemporary Physics. With the support of the propositions of Bakhtin about the potential of the discourse and discursive interactions studies, we identified interesting regularities in how organize discussions among teachers, identifying a scheme that allows us to infer the effectiveness of the enforcement of this form of lead and mediate the discussions in groups of continuous formation of physics teachers to other topics, as well as adding arguments in defense of the groups of discussion as a strategy for continuing formation of teachers.

Complementi ed esercizi di Fisica Tecnica L

Dispensa relativa alle esercitazioni di Fisica Tecnica L tenute il 18-01, 25-01, 01-02 2008

Stenodactilina e lanceolina: due nuove potenti “ribosome-inactivating proteins” bicatenarie. Purificazione, caratterizzazione chimico-fisica e studio dei meccanismi citotossici

Two lectins, called lanceolin and stenodactylin, were purified by affinity chromatography on CL Sepharose 6B from the caudices of the Passifloraceae Adenia lanceolata and Adenia stenodactyla, respectively. They are glycoproteins with Mw of 61,243 (lanceolin) and 63,131 daltons (stenodactylin), consisting of an enzymatic A chain linked to a larger B chain with lectin properties, with N-terminal amino acid sequences similar to that of volkensin, the toxic lectin from Adenia volkensii. These two lectins agglutinate red blood cells, inhibit protein synthesis in a cell-free system as well as in whole cells, and depurinate ribosomes and DNA, but not tRNA or poly(A). They are highly toxic to cells, in which they induce apoptosis and strongly inhibit protein synthesis, and to mice, with LD50s 8.16 mg/kg (lanceolin) and 2.76 mg/kg (stenodactylin) at 48 hours after administration. Thus, lanceolin and stenodactylin have all the properties of the toxic type 2 ribosomeinactivating proteins (RIPs). Further experiments were conducted in order to clarify the effects of these RIPs in cells. We investigated the cronological relationship between cytotoxic activity, indirectly evaluated as inhibition of protein synthesis, and loss of cell viability in NB100 cell line. The induction of apoptosis was assessed by determining caspases 3 and 7 levels, which increase 8-16 hours earlier than the beginning of protein synthesis inhibition. This suggest that the arrest of protein synthesis is not a central event in the pathway of cell poisoning by RIPs. The high toxicity and the induction of cell death only by apoptosis and not by necrosis in two muscular cell lines (TE671 and RD/18) suggest that lanceolin and stenodactylin may be potential candidates for experimental chemoablation in strabism and blepharospasm. These results show that lanceolin and stenodactylin are amongst the most potent toxins of plant origin.