990 resultados para 126-792


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Major element, trace element, and radiogenic isotope compositions of samples collected from Ocean Drilling Program Leg 126 in the Izu-Bonin forearc basin are presented. Lavas from the center of the basin (Site 793) are high-MgO, low-Ti, two-pyroxene basaltic andesites, and represent the products of synrift volcanism in the forearc region. These synrift lavas share many of the geochemical and petrographic characteristics of boninites. In terms of their element abundances, ratios, and isotope systematics they are intermediate between low-Ti arc tholeiites from the active arc and boninites of the outer-arc high. These features suggest a systematic geochemical gradation between volcanics related to trench distance and a variably depleted source. A basement high drilled on the western flank of the basin (Site 792) comprises a series of plagioclase-rich two-pyroxene andesites with calc-alkaline affinities. These lavas are similar to calc-alkaline volcanics from Japan, but have lower contents of Ti, Zr, and low-field-strength elements (LFSE). Lavas from Site 793 show inter-element variations between Zr, Ti, Sr, Ni, and Cr that are consistent with those predicted during crystallization and melting processes. In comparison, concentrations of P, Y, LFSE, and the rare-earth elements (REE) are anomalous. These elements have been redistributed within the lava pile, concentrating particularly in sections of massive and pillowed flows. Relative movement of these two-element groupings can be related to the alteration of interstitial basaltic andesite glass to a clay mineral assemblage by a post-eruptive process. Fluid-rock interaction has produced similar effects in the basement lavas of Site 792. In this sequence, andesites and dacites have undergone a volume change related to silica mobility. As a result of this process, some lithologies have the major element characteristics of basaltic andesite and rhyolite, but can be related to andesitic or dacitic precursors by silica removal or addition.

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Early diagenesis in Leg 126 forearc and backarc sands/sandstones is characterized by the dissolution of intermediate to mafic brown glass, the alteration of colorless rhyolitic glass to clay minerals, precipitation of thin clay-mineral rim cements, and minor precipitation of clinoptilolite cements. Later, more intense diagenesis is restricted to Oligocene forearc basin sediments at Sites 787,792, and 793. In these sections, the effects of early diagenesis have been intensified and overprinted by later diagenetic effects including (1) large-scale dissolution of feldspar and pyroxene crystals, (2) further dissolution of vitric components, (3) precipitation of minor carbonate cements, and (4) pervasive, multiple-staged zeolite cementation. Zeolite minerals present include analcite, mordenite, natrolite, heulandite, wairakite, chabazite, erionite, herschelite, and phillipsite. The latest diagenetic events appear to be the minor dissolution of zeolite cements and the precipitation of minor carbonate and potassium feldspar(?) cements. Observed porosity types include primary interparticles; primary intraparticles in vesicular glass and foraminifers; primary interparticles reduced by compaction and cementation; secondary intraparticles produced by dissolution of feldspar, nonopaque heavy minerals, volcanic glass, and foraminifer tests; and secondary interparticles produced by the dissolution of zeolite cements. Within forearc Oligocene sections at Sites 787 and 792, diagenetic effects appear to decrease with depth in the Oligocene section; however, at Site 793 the majority of samples are intensely altered.

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Subaerial debris flows, with water contents ranging from as little as 10 wt% up to no more than about 25 wt% (Pierson, 1986; Pierson and Costa, 1987), are non-Newtonian fluids that move as fairly coherent masses with yield strength (owing to bulk densities and viscosity that are much greater than those of clear water), which enables them to suspend and transport large clasts. Their flow behavior is thought to be predominantly laminar, although the relative importance of laminar and turbulent flow has not been established and is debatable. They leave deposits (debrites) that are characteristically poorly sorted with large clasts in their middle portions and commonly protruding from their tops. Although generally ungraded or normally graded in their upper portions, many have centimeter- to decimeter-thick inversely graded basal zones (Arguden and Rodolfo, 1990, doi:10.1130/0016-7606(1990)102<0865:SADDBH>2.3.CO;2).

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The Ocean Drilling Program Leg 126 sites may be classified into two categories depending on the presence (Group I: Sites 787, 792, and 793) or absence (Group II: Sites 788, 790, and 791) of steep concentration gradients. Shipboard X-ray diffraction analyses of bulk sediments from Group I sites revealed the presence of a number of diagenetic minerals (some of which are incompatible), but no systematic diagenetic zonation. The results of the chemical analyses of the pore waters from Group I have been used to estimate the activities of dissolved species. Thermodynamic analyses of the composition of the pore waters and the stability of authigenic minerals (gypsum, zeolites, feldspars, smectites, chlorites, and micas) show that the pore waters are close to equilibrium with most of the observed phases. Thus, only a small perturbation of the system (substitution in minerals and fluctuations in pore-water composition, in particular, in pH and SiO2 activity) will cause any of these phases to precipitate. Therefore, one would not expect mineralogical observations to show systematic vertical zonations at these sites. It is suggested that chlorites and high-temperature zeolites are not diagenetic sensu stricto, but were eroded from volcaniclastic highs. The absence of concentration gradients at the Group II sites has been analyzed in terms of reaction kinetics, hydrothermal advection, and temperature distribution. The absence of diagenetic imprints on the pore-water concentration profiles at these sites is probably caused by the slow nucleation of silica phases.

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Sediments and rocks recovered during Ocean Drilling Program Leg 126 at Sites 792 and 793 in the Izu-Bonin forearc basin are described with a primary focus on clay mineralogy. Evidence for diagenetic hydrothermal alteration processes is present in the upper Oligocene to lower Miocene sediments at these sites. The vitric and pumiceous sand/sandstone and pumiceous gravel contain high concentrations of smectites, zeolites, and gypsum. Microscopic observations show that the volcanic glass and feldspars have been altered to smectites and zeolites. The authigenic mineral assemblages indicate that these minerals resulted from precipitation from circulating fluids, as well as from the alteration of glass and feldspar under temperature conditions that may have reached 200°-300°C. Mineral assemblages in microfractures display thermal gradients that possibly reflect cooling effects.

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miR-126 has been implicated in the processes of inflammation and angiogenesis. Through these processes, miR-126 is implicated in cancer biology, but its role there has not been well reviewed. The aim of this review is to examine the molecular mechanisms and clinicopathological significance of miR-126 in human cancers. miR-126 was shown to have roles in cancers of the gastrointestinal tract, genital tracts, breast, thyroid, lung and some other cancers. Its expression was suppressed in most of the cancers studied. The molecular mechanisms that are known to cause aberrant expression of miR-126 include alterations in gene sequence, epigenetic modification and alteration of dicer abundance. miR-126 can inhibit progression of some cancers via negative control of proliferation, migration, invasion, and cell survival. In some instances, however, miR-126 supports cancer progression via promotion of blood vessel formation. Downregulation of miR-126 induces cancer cell proliferation, migration, and invasion via targeting specific oncogenes. Also, reduced levels of miR-126 are a significant predictor of poor survival of patients in many cancers. In addition, miR-126 can alter a multitude of cellular mechanisms in cancer pathogenesis via suppressing gene translation of numerous validated targets such as PI3K, KRAS, EGFL7, CRK, ADAM9, HOXA9, IRS-1, SOX-2, SLC7A5 and VEGF. To conclude, miR-126 is commonly down-regulated in cancer, most likely due to its ability to inhibit cancer cell growth, adhesion, migration, and invasion through suppressing a range of important gene targets. Understanding these mechanisms by which miR-126 is involved with cancer pathogenesis will be useful in the development of therapeutic targets for the management of patients with cancer.

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A genome-wide association study (GWAS) of educational attainment was conducted in a discovery sample of 101,069 individuals and a replication sample of 25,490. Three independent single-nucleotide polymorphisms (SNPs) are genome-wide significant (rs9320913, rs11584700, rs4851266), and all three replicate. Estimated effects sizes are small (coefficient of determination R(2) approximately 0.02%), approximately 1 month of schooling per allele. A linear polygenic score from all measured SNPs accounts for approximately 2% of the variance in both educational attainment and cognitive function. Genes in the region of the loci have previously been associated with health, cognitive, and central nervous system phenotypes, and bioinformatics analyses suggest the involvement of the anterior caudate nucleus. These findings provide promising candidate SNPs for follow-up work, and our effect size estimates can anchor power analyses in social-science genetics.

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In this study, we investigated the expression profiles and clinicopathological significance of miR-126 in large cohort of patients with colorectal cancers as well the cellular repercussions of miR-126 in colon cancer cells along with its targets in-vitro. Down regulation of miR-126 expression was associated with histological subtypes, peri-neural tumour infiltration, microsatellite instability and pathological staging of colorectal cancers (p<0.05). Low miR-126 expression was also associated with poorer survival in patients with colorectal cancer. Analysis of matched tissues from the same patient revealed that approximately 70% of the tested patients had similar levels of expression of miR-126 in primary cancer and cancer metastases in both lymph node and distant metastases. In addition, induced overexpression of miR-126 showed reduced cell proliferation, increased apoptosis and decreased accumulation of cells in the G0-G1 phase of the colon cancer cells. Furthermore, SW480(+miR-126) cells showed reduced BCL-2 and increased P53 protein expression. To conclude, deregulation of miR-126 in colorectal cancer at the tissue and cellular levels as well as its correlation with various clinicopathological parameters confirm the cancer suppressive role of miR-126 in colorectal cancer.

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Contenido: Bien común, justicia y paz / Octavio N. Derisi – La lógica-metafísica del P. José Angulo S. J. / Alberto Caturelli – Dante : aportación escolástica y peculiaridades de su pensar poético-filosófico / G. H. M. Terán – Notas y comentarios -- Bibliografía

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Trata dos princípios, garantias, direitos e deveres para usuários, provedores de serviço e demais agentes envolvidos com o uso da Internet.

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Comissão de tribos indígenas do Alto Rio Negro entrega um documento aos representantes da Fundação Nacional do Índio (FUNAI) comunicando a intenção de liberar suas terras para a exploração de minérios. As lideranças indígenas querem negociar essa exploração com a Assembleia Nacional Constituinte (ANC). Romero Jucá, Presidente da FUNAI, esclarece que essa exploração é uma espécie de autogestão das terras indígenas. João Menezes (PFL-BA) afirma ser necessária a regulamentação urgente da exploração das reservas indígenas, ou proibi-la definitivamente. Antonio Perosa (PMDB-SP) esclarece que a comissão temática votou contra a exploração de minérios em terras indígenas e entende que o setor público tem o direito de detectar a presença de jazidas, mas que a posterior exploração deverá respeitar todo o patrimônio cultural das várias nações indígenas. Será entregue por Bernardo Cabral (PMDN-AM) a segunda versão do anteprojeto de Constituição, feito a partir das propostas das comissões e emendas apresentadas pelos constituintes. Bernardo Cabral (PMDB-AM) comenta o trabalho de compatibilizar as emendas apresentadas e o prazo de entrega da segunda versão do anteprojeto. Os constituintes trabalham na Comissão de Sistematização no sentido de que a nova Constituição modifique alguns pontos na lei do casamento e do planejamento familiar. Israel Pinheiro Filho (PMDB-MG) acha que os casais, principalmente do campo, precisam de orientação para

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The Nostoc 'Fa Tsai' is sometimes seen in Chinese cooking materials stores. It is investigated what 'Fa Tsai' consists of and where it originates.

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In a paper published in this journal in 2001 by Dong [W. G. Dong, X. Y. Huang, and Q. L. Wo, J. Acoust. Soc. Am. 110, 120-126 (2001)] it was claimed that acoustic chaos was obtained experimentally by the nonlinear interaction of two acoustic waves in a duct. In this comment a simple experimental setup and an analytical model is used to show that the dynamics of such systems corresponds to a quasiperiodic motion, and not to a chaotic one. © 2008 Acoustical Society of America.

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利用重离子融合蒸发反应12 2 Sn(11B ,5n2p)布居了双奇核12 6 I的激发态 ,首次建立了具有集体带结构特征的能级纲图 ,其中包括 2 0条新γ跃迁 .所建能级纲图的核素归属指定得到了核反应12 4 Sn(7Li,5n)的交叉支持 .简单讨论了所建带结构的可能组态 .

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报道了高电荷态离子12 6Xeq + (6≤q≤ 30 )入射到固体Al表面产生的 2 0 0~ 10 0 0nm波段的发射光谱的实验结果。实验表明 ,在弱束流 (nA量级 )高电荷态的情况下 ,通过入射离子与固体靶的相互作用可有效地产生原子和离子的复杂组态间跃迁所形成的可见光波段的特征谱线 ,而且当入射离子的电荷剥离数超过一临界值后 (对Al,q=2 6 ) ,谱线相对强度突然显著增强。根据经典过垒模型COB(Theclassicover barriermodel) ,在入射离子的动能较小 (~ 1keV/u)的条件下 ,高电荷态离子与表面相互作用过程中电子的俘获或转移起着非常重要的作用 ,通过提高入射离子的电荷态可增强入射离子俘获电子的能力 ,显著增强激发粒子的光谱线的强度。