998 resultados para 201-1229A
(Table T1) Dissolved carbohydrate concentrations of interstitial waters from seven ODP Leg 201 sites
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Total dissolved carbohydrates (DCHOs) were determined in interstitial waters collected at open-ocean and Peru margin sites cored during Ocean Drilling Program Leg 201. Concentrations of DCHOs ranged from 0 to ~1500 µM and showed no consistent trends between open-ocean and Peru margin sites either in the magnitude or direction of downhole interstitial water gradients. In contrast, relative DCHO concentrations (normalized to dissolved organic carbon concentrations) were higher in open-ocean vs. margin sediments. These trends are consistent with results from more shallow estuarine and nearshore continental margin sediments and may be related to changes in the overall controls on sediment organic matter remineralization with decreasing remineralization rates.
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Proteins and their amino acid building blocks form a major group of biomolecules in all organisms. In the sedimentary environment, proteins and amino acids have two sources: (1) soft tissues and detritus and (2) biotic skeletal structures, dominantly from calcium carbonate-secreting organisms. The focus of this report is on D/L ratios and concentrations of selected amino acids in interstitial waters collected during ODP Leg 201. The Peru margin sites are generally low in carbonates, whereas the open-ocean sites are more carbonate rich. Seifert et al. (1990, doi:10.2973/odp.proc.sr.112.152.1990) reported amino acid concentrations in interstitial waters from Site 681 (ODP Leg 112) comparable to Leg 201 Site 1229.
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Marine sediments harbor an enormous quantity of microorganisms, including a multitude of novel species. The habitable zone of the marine sediment column begins at the sediment-water interface and probably extends to depths of several thousands of meters. Studies of the microbial diversity in this ecosystem have mostly relied on molecular biological techniques. We used a complementary method - analysis of intact polar membrane lipids - to characterize the in-situ microbial community in sediments covering a wide range of environmental conditions from Peru Margin, Equatorial Pacific, Hydrate Ridge, and Juan de Fuca Ridge. Bacterial and eukaryotic phospholipids were only detected in surface sediments from the Peru Margin. In contrast, deeply buried sediments, independent of their geographic location, were dominated by archaeal diether and tetraether lipids with various polar head groups and core lipids. We compared ring distributions of archaeal tetraether lipids derived from polar glycosidic precursors with those that are present as core lipids. The distributions of these related compound pools were distinct, suggestive of different archaeal sources, i.e., the polar compounds derive from sedimentary communities and the core lipids are fossil remnants from planktonic communities with possible admixtures of decayed sedimentary archaea. This in-situ production of distinct archaeal lipid populations potentially affects applications of the TEX86 paleotemperature proxy as demonstrated by offsets in reconstructed temperatures between both pools. We evaluated how varying cell and lipid stabilities will influence the sedimentary pool by using a box-model. The results are consistent with (i) a requirement of continuous inputs of freshly synthesized lipids in subsurface sediments for explaining the observed distribution of intact polar lipids, and (ii) decreasing lipid inputs with increasing burial depth.
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Early diagenetic dolomite beds were sampled during the Ocean Drilling Programme (ODP) Leg 201 at four reoccupied ODP Leg 112 sites on the Peru continental margin (Sites 1227/684, 1228/680, 1229/681 and 1230/685) and analysed for petrography, mineralogy, d13C, d18O and 87Sr/86Sr values. The results are compared with the chemistry, and d13C and 87Sr/86Sr values of the associated porewater. Petrographic relationships indicate that dolomite forms as a primary precipitate in porous diatom ooze and siliciclastic sediment and is not replacing the small amounts of precursor carbonate. Dolomite precipitation often pre-dates the formation of framboidal pyrite. Most dolomite layers show 87Sr/86Sr-ratios similar to the composition of Quaternary seawater and do not indicate a contribution from the hypersaline brine, which is present at a greater burial depth. Also, the d13C values of the dolomite are not in equilibrium with the d13C values of the dissolved inorganic carbon in the associated modern porewater. Both petrography and 87Sr/86Sr ratios suggest a shallow depth of dolomite formation in the uppermost sediment (<30 m below the seafloor). A significant depletion in the dissolved Mg and Ca in the porewater constrains the present site of dolomite precipitation, which co-occurs with a sharp increase in alkalinity and microbial cell concentration at the sulphate-methane interface. It has been hypothesized that microbial 'hot-spots', such as the sulphate-methane interface, may act as focused sites of dolomite precipitation. Varying d13C values from -15 per mil to +15 per mil for the dolomite are consistent with precipitation at a dynamic sulphate-methane interface, where d13C of the dissolved inorganic carbon would likewise be variable. A dynamic deep biosphere with upward and downward migration of the sulphate-methane interface can be simulated using a simple numerical diffusion model for sulphate concentration in a sedimentary sequence with variable input of organic matter. Thus, the study of dolomite layers in ancient organic carbon-rich sedimentary sequences can provide a useful window into the palaeo-dynamics of the deep biosphere.
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Organic matter deposited and buried under the seafloor is one of the major carbon sources for microbial life in the deep subsurface of the ocean. In this report, we present a compilation of all available total organic carbon (TOC) and total inorganic carbon (TIC) data for the sites drilled during Ocean Drilling Program (ODP) Leg 201. We include the TOC and TIC data from sites of Deep Sea Drilling (DSDP) Leg 34 and ODP Legs 112 and 138 (Yeats, Hart, et al., 1976, doi:10.2973/dsdp.proc.34.1976; Suess, von Huene, et al., 1988, doi:10.2973/odp.proc.ir.112.1988; Mayer, Pisias, Janecek, et al., 1992, doi:10.2973/odp.proc.ir.138.1992), which were reoccupied during ODP Leg 201. Additional data from Leg 201 shore-based analyses are also included in the compilation.
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The first experimentally determined temperature dependent oxygen-18 fractionation factor between dolomite and water at low temperatures [Vasconcelos et al. 1995 doi:10.1130/G20992.1] allows now the precise calculation of temperatures during early diagenetic dolomite precipitation. We use d18O values of early diagenetic dolomite beds sampled during ODP Legs 112 and 201 on the Peru continental margin (Sites 1227, 1228 and 1229) [Meister et al. 2007, doi:10.1111/j.1365-3091.2007.00870.x] to calculate paleo-porewater temperatures at the time of dolomite precipitation. We assumed unaltered seawater d18O values in the porewater, which is supported by d18O values of the modern porewater presented in this study. The dolomite layers in the Pleistocene part of the sedimentary columns showed oxygen isotope temperatures up to 5 °C lower than today. Since Sites 1228 and 1229 are located at 150 and 250 m below sealevel, respectively, their paleo-porewater temperatures would be influenced by considerably colder surface water during glacial sealevel lowstands. Thus, Pleistocene dolomite layers in the Peru Continental margin probably formed during glacial times. This finding is consistent with a model for dolomite precipitation in the Peru Margin recently discussed by Meister et al. [Meister et al. 2007, doi:10.1111/j.1365-3091.2007.00870.x], where dolomite forms episodically at the sulphate methane interface. It was shown that the sulphate methane interface migrates upwards and downwards within the sedimentary column, but dolomite layers may only form when the sulphate-methane interface stays at a fixed depth for a sufficient amount of time. We hypothesize that the sulphate-methane interface persists within TOC-rich interglacial sediments, while this zone is buried by TOC-poor sedimentation during glacial times. Thus, the presented oxygen isotope data provide additional information on the timing of early diagenetic dolomite formation and a possible link between episodicity in dolomite formation and sealevel variations. A similar link between early diagenesis and oceanography may also explain spacing of dolomite layers in a Milankovitch type pattern observed in the geological record, such as in the Miocene Monterey Formation.
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Hydroxylated glycerol dialkyl glycerol tetraethers (hydroxy-GDGTs) were detected in marine sediments of diverse depositional regimes and ages. Mass spectrometric evidence, complemented by information gleaned from two-dimensional (2D) 1H-13C nuclear magnetic resonance (NMR) spectroscopy on minute quantities of target analyte isolated from marine sediment, allowed us to identify one major compound as a monohydroxy-GDGT with acyclic biphytanyl moieties (OH-GDGT-0). NMR spectroscopic and mass spectrometric data indicate the presence of a tertiary hydroxyl group suggesting the compounds are the tetraether analogues of the widespread hydroxylated archaeol derivatives that have received great attention in geochemical studies of the last two decades. Three other related compounds were assigned as acyclic dihydroxy-GDGT (2OH-GDGT-0) and monohydroxy-GDGT with one (OH-GDGT-1) and two cyclopentane rings (OH-GDGT-2). Based on the identification of hydroxy-GDGT core lipids, a group of previously reported unknown intact polar lipids (IPLs), including the ubiquitously distributed H341-GDGT (Lipp J. S. and Hinrichs K. -U. (2009) Structural diversity and fate of intact polar lipids in marine sediments. Geochim. Cosmochim. Acta 73, 6816-6833), and its analogues were tentatively identified as glycosidic hydroxy-GDGTs. In addition to marine sediments, we also detected hydroxy-GDGTs in a culture of Methanothermococcus thermolithotrophicus. Given the previous finding of the putative polar precursor H341-GDGT in the planktonic marine crenarchaeon Nitrosopumilus maritimus, these compounds are synthesized by representatives of both cren- and euryarchaeota. The ubiquitous distribution and apparent substantial abundance of hydroxy-GDGT core lipids in marine sediments (up to 8% of total isoprenoid core GDGTs) point to their potential as proxies.
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Contenido: El aristotelismo y el tomismo frente al egoísmo psicológico / María L. Lukac de Stier – El deseo natural de ver a Dios en la Summa contra Gentiles / Guillermo Jorge Cambiasso – La creación como encuentro del ser y de la nada en la teología del maestro Eckhart de Hochheim O.P. (1260-1327) / Brian J. Farrelly – Malebranche y el libertinage érudit / Francisco Leocata – The problem of person and Jean Mouroux / John M. McDermott ; Glenn J. Comandini – Los fundamentos de la Bioética de H. Tristram Engelhardt / Jorge Martínez Barrera – Cuando las contradictorias son verdaderas / Marisa Villalba de Tablón – Examen del escepticismo moral y del relativismo moral / Camilo Tale – Saint Thomas et le mystère de la création : une réponse aux interrogations de l’homme d’aujourd’hui / Marie-Dominique Philippe – La finalidad de la naturaleza humana : alcance y actualidad de la cuestión / Beatriz Eugenia Reyes Oribe – La providencia y el gobierno del mundo / Alberto Caturelli – Saint Thomas et le problème de la possibilité d’un univers créé éternel / Alain-Marie de Lassus – La causalidad material de los elementos en la generación de los cuerpos mixtos / Mario Enrique Sacchi -- Bibliografía
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Consultoria Legislativa - Área I - Direito Constitucional, Eleitoral, Municipal, Direito Administrativo, Processo Legislativo e Poder Judiciário.
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No Plenário da Assembleia Nacional Constituinte (ANC), discussão de emendas populares que tratam dos direitos e da aposentadoria dos trabalhadores e da reforma urbana. O representante da Arquidiocese do Rio de Janeiro, Carlos Roberto Castro, defende uma emenda em favor do usucapião nas favelas cariocas, após cinco anos, e em terrenos urbanos abandonados, após dois anos. Adib Jorge, representante sindical, defende emenda popular que prevê aposentadoria mais justa aos trabalhadores. O Deputado Farabulini Júnior (PTB-SP) defende a paridade dos salários entre os trabalhadores da ativa e os aposentados e pensionistas. Em nome da CUT (Central Única dos Trabalhadores), o Deputado Paulo Paim (PT-RS) fala em defesa da emenda popular dos direitos dos trabalhadores e declara que o eixo dessa emenda é a estabilidade no emprego, as quarenta horas semanais e o direito de greve. Na próxima Sessão Extraordinária serão discutidas emendas populares que tratam da estabilidade no emprego, participação nos lucros e democratização da administração das empresas, reforma urbana, transporte coletivo e moradia popular. O projeto de Constituição do Relator Bernardo Cabral permite o pluralismo sindical. O Deputado Juarez Antunes (PDT-RJ) considera que o pluralismo sindical só favorece a classe empresarial. Marival Campos, Presidente do Sindicato dos Petroleiros-BA, informa que é uma tentativa do patronato de dividir os trabalhadores cada vez mais. Luiz Machado, Presidente do Sindicato dos Urbanitários-RJ, afirma que será desenvolvido um trabalho junto aos parlamentares para que esse dispositivo não seja aprovado. O Deputado Mario Lima (PMDB-BA) informa que só deve haver um sindicato de cada categoria em cada base territorial. O Deputado Afif Domingos (PL-SP) considera que nada impede a coexistência de mais de um sindicato dentro da mesma base, contanto que apenas um seja o representante nos dissídios da categoria perante a lei. O Deputado Paes Landim (PFL-PI) afirma que tanto faz a unicidade ou pluralismo, desde que os sindicatos tenham liberdade e possam atuar livres da interferência do Estado. O Deputado Augusto Carvalho (PCB-DF) declara que só se os trabalhadores se unirem em um único sindicato terão força suficiente para poder enfrentar o patronato.