10 resultados para Helena Chum

em Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho"


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Young and mature larvae of queen and workers of the thief ant, Solenopsis helena, are herein described for the first time. Specimens were treated and described by usual methods of light and scanning electron microscopy. Many of the observed characteristics confirmed traits of the thief ant larva, reinforcing the assumption that they are a distinct group from fire ants. The larva of S. helena can be recognized from other close species by details of the mouthparts, but seem extensively similar to Solenopsis molesta. These findings are useful for taxonomic studies and phylogenetic inferences.

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

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The influence of the axial organic ligand R on the electrochemical oxidation of the compounds [RCoIII(salen)DMF)], where salen is bis(salicylaldehyde)ethylenediimine, and R CH3, C2H5, n-C3H7, n-C4H9, s-C4H9, i-C4H9, CH2Cl, CF3CH2, c-C6H11CH2, c-C6H11, C6H5, C6H5CH2, p-CH3C6H4CH2, and p-NO2C6H4CH2, was studied by means of cyclic voltametry in dimethylformamide (DMF), 0.2 M in tetraethylammonium perchlorate (TEAP), at 25 and -20°C, with a platinum disc working electrode. The above-mentioned compounds can be classified according to their electrochemical behavior. (a) The complexes with R CH3, C2H5, n-C3H7, n-C4H9, c-C6H11CH2, and C6H5 undergo a reversible one-electron oxidation in the 10-50 V s-1 potential scan range. At slower scan rates, the oxidized product decomposes chemically. At -20°C, this chemical step is slow, and a reversible one-electron electrochemical oxidation is observed. (b) The compounds with R CH2Cl, C6H5CH2, p-CH3C6H4CH2 and p-NO2C6H4CH2 undergo a quasi-reversible one-electron oxidation at room temperaure. At -20°C, the electrochemical process becomes more complex. A following chemical reactions is coupled to the quasi-reversible one-electron transfer. Two reduction peaks are observed. (c) The compounds with R i-C4H9, s-C4H9, and c-C6H11 undergo a reversible one-electron oxidation at -20°C. At room temperature, the irreversible chemical reaction following the electron transfer step is too fast to allow the isolation of the electrochemical step. (d) At -20°C, the derivatives with R C2H5, c-C6H11 CH2 and c-C6H11 are adsorbed at the electrode surface. Evidence indicates that the reagent in these reactions is the pentacoordinated species [RCoIII(salen)]. A linear free-energy relationship between E1/2 (for reversible processes) and the Taft polar parameters o* was obtained with a slope of ρ* = 0.25 ± 0.03. As expected, the benzyl derivatives which present mesomeric effects do not fit this polar correlation. The rated of the electrochemical oxidation is also affected by the nature of the ligand R. For the ligands which are strong electron-withdrawing groups and for the benzyl derivatives, the rate of the electrochemical oxidation of the metal ion decreases at room temperature. At lower temperatures, it is suggested that the oxidation to the CoIV-R species is followed by a chemical reaction in which this complex is partly transformed into a CoIII(R*) species, which is reduced at a much more cathodic potential than the Co(IV) species. © 1979.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Genética - IBILCE

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Este artigo propõe-se a refletir como as trajetórias pessoal e profissional de Helena Antipoff (1892-1974), aliadas às suas convicções de que a intervenção e transformação do real decorrem do conhecimento acumulado, da experiência e do desejo de ampliar o bem comum são elementos que vão construindo acervos pessoais, a partir dessa triangulação. Esta construção se funda mais nas práticas e ações do que na intenção de elaborar um acervo, mas termina por compor a construção de uma memória, articulada à formação do “Centro de Documentação e Pesquisa Helena Antipoff” – Ibirité-MG. Nascida na Rússia e tendo vivido no Brasil no período de 1929-1974, a educadora destacou-se por ações socialmente relevantes fundadas na organização do estudo e da pesquisa nos campos da psicologia, da educação e da educação rural, sendo estas duas últimas objetos de nossa pesquisa documental e análises.

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Pós-graduação em Letras - FCLAS

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The first diary written by a woman, Minha vida de menina brings a description of the ordinary daily live and the peaceful live of Diamantina, of the rural Minas Gerais. Helena Morley, a teenager of the end of 19th century, presents us from the crazy city, to issues of liberation of the slaves. The vision world of the young narrator also provides an idea of how the women role has changed in our society.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)