991 resultados para 114-701A


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Pore-water samples were recovered at five sites from ODP Leg 114 in the subantarctic South Atlantic Ocean and analyzed for pH, alkalinity, chloride, sulfate, fluoride, silica, magnesium, calcium, strontium, potassium, lithium, and barium. At sites in the East Georgia Basin and on the Islas Orcadas Rise, Ca increases and Mg decreases linearly downhole with a DeltaMg/DeltaCa ratio reflecting conservative diffusive exchange and basalt basement reactions. At sites on the west flank of the Mid-Atlantic Ridge and on the Meteor Rise, Ca gradients are nonlinear, and nonconservative DeltaMg/DeltaCa ratios reflect alteration reactions of abundant silicic volcanic ash in the sediment. K decreases linearly downhole at all sites, reflecting uptake by basement and the absence of significant sediment-hosted reactions. SO4 decreases and alkalinity increases downhole are due to a slight sulfate reduction at all sites except at Site 701. Sr increases downhole at all sites except Site 701, with DeltaSr/DeltaCa ratios reflecting diffusive exchange with basement. At Site 704 on the Meteor Rise, there is intense Sr production during carbonate recrystallization in the upper 200 mbsf. Below 200 mbsf at Site 704, the ion concentration product of SrSO4 is constant, suggesting Sr control by celestite solubility. Li and F concentrations display complex behavior related to sedimentary reactions, probably calcite recrystallization (Li uptake and F release).

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We have studied the sedimentary and basaltic inputs of lithium to subduction zones. Various sediments from DSDP and ODP drill cores in front of the Mariana, South Sandwich, Banda, East Sunda and Lesser Antilles island arcs have been analysed and show highly variable Li contents and d7Li values. The sediment piles in front of the Mariana and South Sandwich arcs largely consist of pelagic sediments (clays and oozes). The pelagic clays have high Li contents (up to 57.3 ppm) and Li isotope compositions ranging from +1.3? to +4.1?. The oozes have lower Li contents (7.3-16 ppm) with d7Li values of the diatom oozes from the South Sandwich lower (+2.8? to +3.2?) than those of the radiolarian oozes from the Mariana arc (+8.1? to +14.5?). Mariana sediment also contains a significant portion of volcanogenic material, which is characterised by a moderate Li content (14 ppm) and a relatively heavy isotope composition (+6.4?). Sediments from the Banda and Lesser Antilles contain considerable amounts of continental detritus, and have high Li contents (up to 74.3 ppm) and low d7Li values (around 0?), caused by weathering of continental bedrock. East Sunda sediments largely consist of calcareous oozes. These carbonate sediments display intermediate to high Li contents (2.4-41.9 ppm) and highly variable d7Li values (-1.6? to +12.8?). Basaltic oceanic crust samples from worldwide DSDP and ODP drill cores are characterised by enrichment of Li compared to fresh MORB (6.6-33.1 vs. 3.6-7.5 ppm, respectively), and show a large range in Li isotope compositions (+1.7? to +11.8?). The elemental and isotopic enrichment of Li in altered basalts is due to the uptake of isotopically heavy seawater Li during weathering. However, old oceanic crust samples from Sites 417/418 exhibit lighter Li isotope compositions compared to young basaltic crust samples from Sites 332B and 504B. This lighter Li isotope signature in old crust is unexpected and further research is needed to explore this issue.

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Late Miocene to Holocene planktonic foraminifers from the subantarctic South Atlantic were investigated for their biostratigraphic and environmental significance. The calcareous planktonic microfauna are of low diversity and are very rare or absent at sites located below the CCD. The sediments recovered from Sites 703 and 704 on the Meteor Rise at about 47°S are useful for biostratigraphic and environmental studies. In the whole sequence 16 species or varieties of planktonic foraminifers were recognized. Two species occur in the uppermost Miocene. In the Pliocene the Globorotalia puncticulata population can be used to separate the early from the late Pliocene. The Pliocene/Quaternary boundary does not appear to be well distinguished in the foraminiferal assemblage. A faunal change noted at 2.5 Ma could correspond to the development of glaciation in the Northern Hemisphere and its Antarctic counterpart. At about 5.2 Ma the first increase in polar fauna near the Meteor Rise occurs. Two other cooling periods are indicated in these sequences at about 4 and 3 Ma. Moreover, the hydrologic environment became more productive at about 2.1 Ma and close to the Brunhes/Matuyama boundary.

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Petrographic and geochemical investigations were carried out on 21 ash layers from four sites of ODP Legs 113 and 114 in the southern Atlantic Ocean. With the help of geochemical data and petrographic characterization three rock series can be distinguished for stratigraphically different ash layers from Site 701 (Leg 114) located east of the South Sandwich Island Arc, whereas the Leg 113 tephras from the southern slope of the South Orkney Microcontinent belong to another magmatic series. Geochemical correlation of the Leg 113 tephras with possible source areas indicates that they were probably erupted from the Antarctic Peninsula. The Miocene ashes from Site 701 are probably derived from the now-extinct Discovery Arc, the precursor of the South Sandwich Islands. The Pliocene ashes from the site show some affinity with the South Shetland Islands, although the available data do not permit a clear correlation. The Quaternary ashes from Site 701 display a chemistry typical of island-arc tholeiites and are therefore most probably derived from eruptions on the South Sandwich Islands. Because of their distant position the southern Andes seem to be rather improbable as a potential source region for the tephra layers investigated.

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This paper presents new major and trace-element data and Lu-Hf and Sm-Nd isotopic compositions for representative suites of marine sediment samples from 14 drill sites outboard of the world's major subduction zones. These suites and samples were chosen to represent the global range in lithology, Lu/Hf ratios, and sediment flux in subducting sediments worldwide. The data reported here represent the most comprehensive data set on subducting sediments and define the Hf-Nd isotopic variations that occur in oceanic sediments and constrain the processes that caused them. Using new marine sediment data presented here, in conjunction with published data, we derive a new Terrestrial Array given by the equation, epsilon-Hf = 1.55 * epsiolon-Nd + 1.21. This array was calculated using >3400 present-day Hf and Nd isotope values. The steeper slope and smaller y-intercept of this array, compared to the original expression (epsilon-Hf = 1.36 * epsilonNd + 2.89; Vervoort et al., 1999, doi:10.1016/S0012-821X(99)00047-3) reflects the use of present day values and the unradiogenic Hf of old continental samples included in the array. In order to examine the Hf-Nd isotopic variations in marine sediments, we have classified our samples into 5 groups based on lithology and major and trace-element geochemical compositions: turbidites, terrigenous clays, and volcaniclastic, hydrothermal and hydrogenetic sediments. Compositions along the Terrestrial Array are largely controlled by terrigenous material derived from the continents and delivered to the ocean basins via turbidites, volcaniclastic sediments, and volcanic inputs from magmatic arcs. Compositions below the Terrestrial Array derive from unradiogenic Hf in zircon-rich turbidites. The anomalous compositions above the Terrestrial Array largely reflect the decoupled behavior of Hf and Nd during continental weathering and delivery to the ocean. Both terrigenous and hydrogenetic clays possess anomalously radiogenic Hf, reflecting terrestrial sedimentary and weathering processes on the one hand and marine inheritance on the other. This probably occurs during complementary processes involving preferential retention of unradiogenic Hf on the continents in the form of zircon and release of radiogenic Hf from the breakdown of easily weathered, high Lu-Hf phases such as apatite.

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The viscosities of ternary mixtures of R-12, R-22, and R-114 vapors were determined at ambient temperature and pressure within +-1% by using an oscillating disk viscometer. The empirical viscosity obtained by Wllke's equation compares very well with the experimental results obtained with this vlscometer. In the case of this ternary vapor mixture, as long as the molar fraction ratio of R-12 to R-114 Is maintained at approximately 2"' (=Inverse ratio of thelr molecular weights) the viscosity of the ternary mixture at ambient temperature and pressure remalns constant irrespective of the percentage of R-22 present in the mixture.

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Contenido: Tomás de Aquino en su VII centenario / Gustavo Eloy Ponferrada – Santo Tomás y los capítulos generales de la orden de los Hermanos Predicadores, 1278-1370 / J. E. Bolzán ; Azucena A. Fraboschi – Jacques Chevalier et le Thomisme / Alain Guy – Notas y comentarios -- Bibliografía

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A Assembleia Nacional Constituinte (ANC) propõe ao idoso aposentadoria integral, com valor igual ao maior salário do último ano de trabalho. Arnaldo Faria de Sá (PTB-SP) concorda com a proposta. Eduardo Moreira (PMDB-SC) diz que o aposentado será lembrado nesta Constituição, de tal forma que mantenha seu poder aquisitivo. Com relação ao tempo de serviço necessário para a aposentadoria, não houve inovações. Geraldo Alckmin (PMDB-SP) diz que a Constituinte estabeleceu o Sistema Único de Previdência Social e o Sistema Único de Saúde, através do INAMPS, para fazer justiça ao trabalhador rural e fixar o homem no campo. Na sessão O Povo Pergunta, cidadão quer saber o que os constituintes vão fazer em relação a pobreza. Ruberval Piloto (PDS-SC) responde que, para sanar a pobreza, é necessário dar um salário mais justo para a parte menos assistida da população, garantir cidadania social (casa, terra e comida) e melhor distribuição de renda entre a União, Estados e Municípios. A Comissão de Sistematização realizou a primeira reunião para discutir o anteprojeto de Constituição. A ausência do Relator Bernardo Cabral (PMDB-AM) impediu a discussão do anteprojeto. José Genoíno (PT-SP) diz que é impossível discutir o anteprojeto sem o relatório. José Richa (PMDB-PR) relata que o anteprojeto está fora da realidade, como é o caso da estabilidade no emprego após 90 dias de trabalho. Vivaldo Barbosa (PDT-RJ) está preocupado com alguns temas, como a questão do direito de propriedade e da reforma agrária. Nelson Jobim (PMDB-RS) explica que o anteprojeto é uma síntese do que foi aprovado nas comissões e, neste momento, não é possível fazer alterações.

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The Olympic Coast National Marine Sanctuary (OCNMS) continues to invest significant resources into seafloor mapping activities along Washington’s outer coast (Intelmann and Cochrane 2006; Intelmann et al. 2006; Intelmann 2006). Results from these annual mapping efforts offer a snapshot of current ground conditions, help to guide research and management activities, and provide a baseline for assessing the impacts of various threats to important habitat. During the months of August 2004 and May and July 2005, we used side scan sonar to image several regions of the sea floor in the northern OCNMS, and the data were mosaicked at 1-meter pixel resolution. Video from a towed camera sled, bathymetry data, sedimentary samples and side scan sonar mapping were integrated to describe geological and biological aspects of habitat. Polygon features were created and attributed with a hierarchical deep-water marine benthic classification scheme (Greene et al. 1999). For three small areas that were mapped with both side scan sonar and multibeam echosounder, we made a comparison of output from the classified images indicating little difference in results between the two methods. With these considerations, backscatter derived from multibeam bathymetry is currently a costefficient and safe method for seabed imaging in the shallow (<30 meters) rocky waters of OCNMS. The image quality is sufficient for classification purposes, the associated depths provide further descriptive value and risks to gear are minimized. In shallow waters (<30 meters) which do not have a high incidence of dangerous rock pinnacles, a towed multi-beam side scan sonar could provide a better option for obtaining seafloor imagery due to the high rate of acquisition speed and high image quality, however the high probability of losing or damaging such a costly system when deployed as a towed configuration in the extremely rugose nearshore zones within OCNMS is a financially risky proposition. The development of newer technologies such as intereferometric multibeam systems and bathymetric side scan systems could also provide great potential for mapping these nearshore rocky areas as they allow for high speed data acquisition, produce precisely geo-referenced side scan imagery to bathymetry, and do not experience the angular depth dependency associated with multibeam echosounders allowing larger range scales to be used in shallower water. As such, further investigation of these systems is needed to assess their efficiency and utility in these environments compared to traditional side scan sonar and multibeam bathymetry. (PDF contains 43 pages.)

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Until now observations on the temporal variation of size of freshwater copepods have not provided much information. Other observers only mention in passing this or that phenomenon from which it is possible to deduct termporal variations. In this study Cyclops strenuus s.l., a freshwater species of fairly wide distribution, is studied in two water bodies. The author studies the systematic, placing of inhabitants described as C. strenuus Fischer in both locations, their annual life cycle, and their annual size variations.

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Experimental studies were carried out on the transformation of matter and energy during embryonic development of the isopod Crustacea Asellus aquaticus L. under two constant temperatures. Material for the experiments was collected in the quarry lakes of the Kurasovshchin-zone (city-Minsk) at 9°C in April and at 18°C in June, 1977. The rate of consumption of oxygen per specimen by eggs and embryos of Asellus aquaticus was observed and dynamics of the basic biological characteristics during embryonic development studied.

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The osmotic pressure of the perivitelline fluid and the yolk of trout (Salmo trutta) eggs were measured separately by the Drucker-Schrein method. The permeability of the egg membrane and the variations in the osmotic pressure of the eggs when placed in salt solutions were also investigated.