991 resultados para 162-981


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Multisensor track data, including magnetic susceptibility, gamma-ray attenuation porosity evaluator (GRAPE) wet bulk density, and natural gamma emission, were collected on all cores recovered during Ocean Drilling Program Leg 162. Data from the upper Pliocene and lower Pleistocene of Sites 981 and 984 are here compared to results from analyses of a limited set of discrete samples, including benthic foraminiferal isotopic composition, grain size, carbonate content, abundance of foraminifers and lithic particles, and clay mineralogy. Natural gamma emission most closely monitors the input of felsic terrigenous material to these two sites. Magnetic susceptibility also tracks felsic terrigenous input at Site 981 but appears to reflect a separate, more mafic, terrigenous component at Site 984. The GRAPE record does not correlate well with any discretely measured variable at Sites 981 or 984.

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We generated benthic isotope records from Ocean Drilling Program (ODP) site 981 on the Feni drift (2173 m water depth) and from ODP site 983 on the Gardar drift (1983 m water depth) to examine the interaction between North Atlantic Deep Water (NADW) and Glacial North Atlantic Intermediate Water (GNAIW) formation from 2.0 to 1.4 Ma. We find NADW at both sites during interglacial periods, and a mix of NADW and Southern Ocean water at the Feini drift during most glacial periods. Prior to 1.7 Ma we find no evidence ofr GNAIW at the Gardar drift site. Instead, glacial Gardar drift delta13C values are as low or lower than values for all other sites in the North Atlantic and reflect continued glacial overflow from the Nordic seas. After 1.7 Ma Gardar drift delta13C values increase and suggest that there was GNAIW at the Gardar drift site during some glacial intervals. Overall, we find that NADW and GNAIW production changed around 1.7 Ma in concert with changes in sea surface temperature and salinity and in the Earth's obliquity cycle.

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Magnetic polarity stratigraphies for Sites 980-984 are based on shipboard measurements from the pass-through magnetometer after alternating field (AF) demagnetization at a peak field of 25 mT and shore-based stepwise AF demagnetization of discrete samples. The characteristic magnetization component was determined after AF demagnetization removed the steep downward drill-string-related magnetic overprint. Peak AF fields in the 20-30 mT range were required to resolve the component, carried by magnetite, that was used to produce unambiguous Pliocene-Pleistocene magnetic stratigraphies at all five sites. At Sites 980 and 983, magnetic stratigraphies were resolved to the base of the recovered advanced hydraulic piston corer (APC) section, which lies in the Matuyama Chron (1r.2r) and Olduvai Subchron (2n), respectively. At Sites 981 and 982, magnetization intensities decrease sharply in the normal polarity zone corresponding to the Gauss Chron (2An), and magnetic stratigraphies below this level could not be resolved. At Site 984, the resolution of magnetic stratigraphy was curtailed at ~250 meters below seafloor (Olduvai Subchron) by core deformation at the base of the APC section and in the underlying extended core barrel section. As the magnetic stratigraphies at all four sites are unequivocal, polarity chron interpretations can be made without aid from the biostratigraphy. Mean sedimentation rates within polarity chrons have been calculated and Pliocene-Pleistocene biomagnetostratigraphic correlations tested.

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Deoxyhypusine hydroxylase (DOHH) catalyzes the final step in the post-translational synthesis of an unusual amino acid hypusine (N-(sic)-(4-amino-2-hydroxybutyl) lysine), which is present on only one cellular protein, eukaryotic initiation factor 5A (eIF5A). We present here the molecular and structural basis of the function of DOHH from the protozoan parasite, Leishmania donovani, which causes visceral leishmaniasis. The L. donovani DOHH gene is 981 bp and encodes a putative polypeptide of 326 amino acids. DOHH is a HEAT-repeat protein with eight tandem repeats of alpha-helical pairs. Four conserved histidine-glutamate sequences have been identified that may act as metal coordination sites. A similar to 42 kDa recombinant protein with a His-tag was obtained by heterologous expression of DOHH in Escherichia coli. Purified recombinant DOHH effectively catalyzed the hydroxylation of the intermediate, eIF5A-deoxyhypusine (eIF5A-Dhp), in vitro. L. donovani DOHH (LdDOHH) showed similar to 40.6% sequence identity with its human homolog. The alignment of L. donovani DOHH with the human homolog shows that there are two significant insertions in the former, corresponding to the alignment positions 159-162 (four amino acid residues) and 174-183 (ten amino acid residues) which are present in the variable loop connecting the N- and C-terminal halves of the protein, the latter being present near the substrate binding site. Deletion of the ten-amino-acid-long insertion decreased LdDOHH activity to 14% of the wild type recombinant LdDOHH. Metal chelators like ciclopirox olamine (CPX) and mimosine significantly inhibited the growth of L. donovani and DOHH activity in vitro. These inhibitors were more effective against the parasite enzyme than the human enzyme. This report, for the first time, confirms the presence of a complete hypusine pathway in a kinetoplastid unlike eubacteria and archaea. The structural differences between the L. donovani DOHH and the human homolog may be exploited for structure based design of selective inhibitors against the parasite.

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Contenido: La causa IV : necesidad de la primera causa o acto de Dios / Octavio N. Derisi -- La cuestión del "paso" indebido de las proposiciones especulativas a las prácticas y la respuesta de Tomás de Aquino / Carlos I. Massini -- Significado del pensamiento de Michele Federico Sciacca para el hombre de hoy / Alberto Caturelli -- La sociedad nacional y la sociedad internacional para el análisis de la doctrina social de la Iglesia / Pedro E. Baquero Lazcano -- Notas y comentarios -- Bibliografía

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Foi testada a porta de detector de metais posicionada na entrada das galerias do Plenário. É um equipamento de segurança com cem por cento de tecnologia nacional. O Deputado Jorge Arbage (PDS-PA) informa que a porta estava dentro do programa estabelecido para as normas de segurança da Assembleia Nacional Constituinte (ANC). O Deputado Mauro Miranda (PMDB-GO) defende emendas em favor da autonomia dos municípios. O Deputado Amaury Muller (PDT-RS) declara que o Poder Executivo não tem respondido os requerimentos de informações do Poder Legislativo e considera isso um desrespeito à soberania da Constituinte. Na sessão O Povo Pergunta, cidadã quer saber o que muda no direito de expressão. O Deputado Ruy Nedel (PMDB-RS) responde que o "direito de dizer" já mudou com a queda da ditadura e cita as figuras da Inconstitucionalidade por Omissão e do Defensor do Povo como formas de mudar o direito de fazer a Constituição ser cumprida. Jair Meneguelli, Presidente da Central Única dos Trabalhadores (CUT), conclama a população a assinar as emendas populares.

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Opinião de cidadãos sobre a proposta de aprovar a nova Constituição através de plebiscito. Dois projetos de resolução, apresentados pelos Deputados Brandão Monteiro (PDT-RJ) e Virgílio Guimarães (PT-MG). estabelecem que, após 90 dias da promulgação da nova Carta, ela seja aprovada por um plebiscito. O Deputado Virgílio Guimarães (PT-MG) considera que a palavra final cabe ao eleitor. O Deputado Alceni Guerra (PFL-PR) quer plebiscitos parciais, por temas. Em debate promovido pelo 1º Secretário da Assembleia Nacional Constituinte Marcelo Cordeiro, líderes partidários fazem um balanço do projeto de Constituição. O Deputado Brandão Monteiro (PDT-RJ) rejeita a ideia de chamar de "monstrengo" a nova Constituição, mas diz que ela precisa de ajustes. O Deputado Luiz Henrique (PMDB-SC) declara ser fundamental o entendimento dos partidos nas questões polêmicas, para que se faça uma Constituição moderna. José Carlos Coutinho (PL-RJ) critica o aproveitamento, no projeto, do texto do substitutivo recusado na Comissão de Educação da Assembleia Nacional Constituinte (ANC). O Senador Carlos Chiarelli (PFL-RS) declara que a negociação é urgente e indispensável. O Deputado Bonifácio de Andrada (PDS-MG) considera que as negociações permitirão o consenso na votação no Plenário. A Deputada Irma Passoni (PT-SP) declara que cada partido deve afirmar seus princípios, mas também trabalhar para uma negociação possível no sentido de alcançar as necessidades atuais da nação brasileira. Cidadãos assinam as emendas populares nos pontos mais movimentados das cidades. As principais emendas populares que estão circulando pelo país tratam dos seguintes temas: direito dos trabalhadores; direitos da mulher; conselho de comunicação; educação.