998 resultados para 175-1076A


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A multiproxy approach including the use of stable isotopes, magnetic characterization analyses, and organic geochemistry has been adopted to consider factors such as productivity and terrigenous input over the past 1.5 m.y. at two areas off the western coast of Africa. These factors can, in turn, be used to consider variability in ocean circulation and upwelling in addition to changes in climate on the African continent. In particular, studies focused on the influence of glacial-interglacial cycles and evidence for the mid-Pleistocene revolution (MPR), a complex change in climate that occurred at ~1 Ma. A comparison of the records from the two areas drilled during Ocean Drilling Program Leg 175, the Congo Basin, at a latitude of 5°S (Holes 1076A and 1077A), and the Walvis Ridge, at 17°S (Hole 1081A), demonstrates that these sites are affected by different localized factors. The sites in the Congo Basin are strongly influenced by freshwater and sediment from the Congo River, whereas the site at the Walvis Ridge is located in the center of oceanic upwelling and contains a more marine signal. Evidence also suggests that the two sites responded differently to both long- and short-term climatic variations. In particular, the response at the Walvis Ridge to the MPR occurred over an extended period, from 1.1 to 0.8 Ma, and was associated with a change in the dominant source of terrigenous input to the site in conjunction with a change in the productivity signal. In the Congo Basin, the response to the MPR was more rapid, occurring between 0.9 and 0.8 Ma. During this period, the influence of the Congo River became significant. However, productivity records only began to respond toward the end of this interval, at 0.8 Ma.

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The role of invariant water molecules in the activity of plant cysteine protease is ubiquitous in nature. On analysing the 11 different Protein DataBank (PDB) structures of plant thiol proteases, the two invariant water molecules W I and W2 (W220 and W222 in the template 1PPN structure) were observed to form H-bonds with the Ob atom of Asn 175. Extensive energy minimization and molecular dynamics simulation studies up to 2 ns on all the PDB and solvated structures clearly revealed the involvement of the H-bonding association of the two water molecules in fixing the orientation of the asparagine residue of the catalytic triad. From this study, it is suggested that H-bonding of the water molecule at the W1 invariant site better stabilizes the Asn residue at the active site of the catalytic triad.

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Digital image

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Contenido: La prudencia (I) / Octavio Nicolás Derisi – Sujeto, acto y operación / Daniel Gamarra – Sobre la naturaleza de los “derechos” / Héctor H. Hernández – Decir lo mismo (Frege y Santo Tomás) / Juan J. Sanguineti – La teoría del tiempo en Ockham y la autenticidad de la Summulae in Libros Physicorum / Olga L. Larre ; J. E. Bolzán – Filosofía cristiana y apologética en Mons. Audino Rodríguez y Olmos / Alberto Caturelli – Notas y comentarios -- Bibliografía

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Consultoria Legislativa - Área IV - Matéria Orçamentária Pública.

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The neutron deficient nuclide Ir-175 was produced by irradiation of Nd-146 with 210 MeV Cl-35 via a fusion-evaporation reaction channel. The reaction products were transported to a low-background location using a helium-jet recoil fast-moving tape-transport system for measurement. The experimental devices and data analysis method are introduced. Based on the decay-curve fitting of the beta-delayed gamma ray from Ir-175, realized by the least-square method, a new long-lived isomeric state of Ir-175 is proposed and briefly discussed.

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57 fotografías, cicuenta y cuatro a color.

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