733 resultados para Hoplias aff. malabaricus


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Benthic foraminiferal and calcareous nannofossil assemblages, as well as stable isotope data from the Campanian/Maastrichtian boundary interval (~71.4 to ~70.7 Ma) of the Kronsmoor section (North German Basin), were investigated in order to characterize changes in surface-water productivity and oxygen content at the seafloor and their link to climatic and paleoceanographic changes. A nutrient index based on calcareous nannofossils is derived for the high-latitude, epicontinental North German Basin, reflecting changes in surface-water productivity. Oxygen isotopes of well-preserved planktic foraminiferal specimens of Heterohelix globulosa reflect warmer surface-water temperatures in the lower part of the studied succession and a cooling of up to 2°C (0.5 per mil) in the upper part (after 71.1 Ma). For the lower and warmer part of the investigated succession, benthic foraminiferal assemblages and the calcareous nannofossils indicate well-oxygenated bottom waters and low-surface water productivity. In contrast, the upper part of the succession is characterized by cooler conditions, lower oxygen content at the seafloor and increasing surface-water productivity. It is proposed that the cooling phase starting at 71.1 Ma was accompanied by increasing surface-water mixing caused by westerly winds. As a consequence of mixing, nutrients were advected from sub-surface waters into the mixed layer, resulting in increased surface-water productivity and enhanced organic matter flux to the seafloor. We hypothesize that global sea-level fall during the earliest Maastrichtian (~71.3 Ma), indicated by decreasing carbon isotope values, may have led to a weaker water mass exchange through narrower gateways between the Boreal Realm and the open North Atlantic and Tethys oceans. Both the weaker water mass exchange and enhanced surface-water productivity may have led to slightly less ventilated bottom waters of the upper part of the studied section. Our micro-paleontological and stable isotopic approach indicates short-term (<100 kyr) changes in oxygen consumption at the seafloor and surface-water productivity across the homogeneous Boreal White Chalk succession of the North German Basin.

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Ocean anoxic events were periods of high carbon burial that led to drawdown of atmospheric carbon dioxide, lowering of bottom-water oxygen concentrations and, in many cases, significant biological extinction (Arthur et al., 1990; Erbacher et al., 1996, doi:10.1130/0091-7613(1996)024<0499:EPORAO>2.3.CO;2; Kuypers et al., 1999, doi:10.1038/20659; Jenkyns, 1997; Hochuli et al., 1999, doi:10.1130/0091-7613(1999)027<0657:EOHPAC>2.3.CO;2). Most ocean anoxic events are thought to be caused by high productivity and export of carbon from surface waters which is then preserved in organic-rich sediments, known as black shales. But the factors that triggered some of these events remain uncertain. Here we present stable isotope data from a mid-Cretaceous ocean anoxic event that occurred 112 Myr ago, and that point to increased thermohaline stratification as the probable cause. Ocean anoxic event 1b is associated with an increase in surface-water temperatures and runoff that led to decreased bottom-water formation and elevated carbon burial in the restricted basins of the western Tethys and North Atlantic. This event is in many ways similar to that which led to the more recent Plio-Pleistocene Mediterranean sapropels, but the greater geographical extent and longer duration (~46 kyr) of ocean anoxic event 1b suggest that processes leading to such ocean anoxic events in the North Atlantic and western Tethys were able to act over a much larger region, and sequester far more carbon, than any of the Quaternary sapropels.

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Detailed analysis of over 200 samples of uppermost Cretaceous and Paleocene sediments from Atlantic Ocean DSDP Sites 384, 86, 95, 152, 144, 20C, 21, 356, 357, and 329 provides new information on the temperature stratification of Paleocene planktonic foraminifera, the temperature and carbon isotopic changes across the Cretaceous/Tertiary boundary, and the fluctuating temperature and carbon isotopic records through the Paleocene ~64.5-54 m.y.). There was a significant temperature rise across the Cretaceous/Tertiary boundary both at the surface and in deep waters of the Atlantic Ocean. This temperature rise occurred before the basal Tertiary 'Globigerina' eugubina Zone, so that in the oldest Paleocene sample yet analyzed from the deep sea (Site 356) temperatures are already three degrees higher at the bottom and at the surface than in the Cretaceous. The temperature rise across the boundaryis more pronounced on the bottom and in samples from higher latitudes. Accompanying the temperature rise across the boundary there is a significant shift in the carbon isotope profile. In the basal Paleocene the foraminifera of the surface zone demonstrate very negative carbon isotope values (unlike in the Cretaceous of today's ocean), while deeper dwelling species have more positive values which then decrease to the bottom. The unusual carbon isotope gradients persist through the first three million years of the Paleocene until towards the top of planktonic foraminiferal Zone P.1 (G. trinidadensis Zone) the foraminifera record a profile more positive at the surface and decreasing towards the bottom (as in today's ocean). During the Paleocene there are two noteworthy rises in surface water temperature; the first around 62-61 m.y. (G. trinidadensis Zone), and the second near the base of the Globorotalia angulata Zone, 60-59 m.y. At this time surface temperatures at low to mid latitudes reached values near 25°C, while at mid-latitude Site 384 temperature highs near 22°C were registered. At a sample spacing of around one per million years, we have only produced some of the detail of these temperature fluctuations. The later Paleocene is generally cooler and there do not seem to be any large variations either through time or latitude. Middle-latitude sites average temperatures near 15°C at the surface, while high lower latitude site temperatures range near 18°C. The most salient feature of the bottom temperature record (based on multispecific samples) through the Paleocene is its lack of fluctuations. There is an overall temperature range of 5°C at these intermediate depth sites (paleodepth estimates between 1500 and 3000 m). Higher values near 13°C accompany the surface temperature peaks around 62 and 60 m.y., while low values near 8°C occur in Zone P.2 (61-60 m.y.). We detected no change in bottom temperature across the paleocene/Eocene boundary in the few samples studied so far. While there are several fluctuations in the carbon isotope values through the early Paleocene, the general trend is one of increasingly positive values at the surface and at depth. This trend culminates in the late Paleocene (upper Zone P.4, about 56-57 m.y.) with a major excursion in the carbon isotope values. At low latitudes the range between the surface and the deepest planktonic foraminifera is a delta13C of 4 per mil as compared with a range of 2 per mil today. The carbon values drop off slightly, but remain strongly positive through the remainder of the Paleocene at most sites. Accompanying the carbon isotope excursion at Site 384 is a productivity increase and a proposed rise in the CCD.

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With the growing pressure of eutrophication in tropical regions, the Mauritian shelf provides a natural situation to understand the variability in mesotrophic assemblages. Site-specific dynamics occur throughout the 1200 m depth gradient. The shallow assemblages divide into three types of warm-water mesotrophic foraminiferal assemblages, which is not only a consequence of high primary productivity restricting light to the benthos but due to low pore water oxygenation, shelf geomorphology, and sediment partitioning. In the intermediate depth (approx. 500 m), the increase in foraminiferal diversity is due to the cold-water coral habitat providing a greater range of micro niches. Planktonic species characterise the lower bathyal zone, which emphasizes the reduced benthic carbonate production at depth. Although, due to the strong hydrodynamics within the Golf, planktonic species occur in notable abundances through out the whole depth gradient. Overall, this study can easily be compared to other tropical marine settings investigating the long-term effects of tropical eutrophication and the biogeographic distribution of carbonate producing organisms.

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A quantitative radiolarian study at Ocean Drilling Program Site 1241 in the eastern tropical Pacific enables us to reconstruct paleoceanographic changes that occurred since the latest middle Miocene. Today, this site is located just under the Eastern Pacific Warm Pool (EPWP). Based on the abundance variations of radiolarian characteristic species which are indicators of upwelling and thermocline changes, it is suggested that three notable changes occurred at 10.6, 9.8, and 4.2 Ma in the region. Four distinct periods of oceanographic conditions bounded by these notable changes were characterized on the basis of the following: (1) stratified seawater (12.0 to 10.6 Ma); (2) a shallowing of the thermocline and an increasing of upwelling (10.6 to 9.8 Ma); (3) significant inflow of warm water to the eastern tropical Pacific caused by an intensified Northern Equatorial Countercurrent (NECC), resulting in the formation of EPWP (9.8 to 4.2 Ma); and (4) the reduction of the EPWP and the NECC, and an increase in upwelling (4.2 to 0 Ma). The timing of these paleoceanographic events indicated the strong relations with the opening and closing of the Indonesian and Central American (Panama) Seaways. The reduction of the EPWP (this study) and the deepening of the thermocline in western Pacific at about 4.2 Ma (Cannariato and Ravelo, 1997; Chaisson and Ravelo, 2000) indicated a change from a state resembling El Niño in the late Miocene and the early Pliocene time to a state resembling La Niña by the late Pliocene

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Calcareous nannofossils from upper Campanian-lower Maestrichtian Deep Sea Drilling Project Leg 71 Cores 511-23 and 511-24 are described and correlated with assemblages of similar age from piston and drill cores on the Falkland Plateau, South Atlantic Ocean. The Leg 71 cores partially fill a drilling gap of at least 20 meters left within a thick (50 m) carbonate section first drilled by DSDP Leg 36 at Site 327. Cores 511-23 and 511-24 both fall within the upper portion of the Biscutum coronum Zone of Wind and demonstrate an overlap in the range of Monomarginatus quaternarius with the ranges of M. pectinatus, Misceomarginatus pleniporus, and Biscutum coronum across the Campanian/ Maestrichtian boundary. Resolution of the sequence of highest occurrence datums for the latter species must await the recovery of a more complete section. Comparison of the Site 511 assemblages with those from Mas Orcadas Core 07-75-44 to the north confirms earlier speculation that the Falkland Plateau served as an important boundary between major water masses during the Late Cretaceous.

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Th is book celebrates – while also acknowledging the huge challenges it faces – a particular kind of feminism, one that has been concerned with challenging both fundamentalism and racism. It consists of the autobiographical political narratives of feminist activists of diff erent ethnic and religious backgrounds who have been members of Women Against Fundamentalism (WAF), a feminist anti-racist and antifundamentalist organisation that was established in London in 1989, at the heart of the Salman Rushdie aff air. Political narratives have been described as ‘stories people tell about how the world works’, the ways in which they explain the engines of political change, and as refl ections on the role people see themselves and their group playing in their ongoing struggles.1 And the contributors to this book off er just such narratives – they talk about the trajectories of their lives, and how they see themselves and the groups to which they belong in relation to the wider political struggles in which they have been involved. WAF women have shared solidarity and trust, based on common political values, but, as can be seen from the chapters of this book, their perspectives – as well as their personal/ political histories – have also diff ered.2 Th is variety of voices is signifi - cant not only for these women as individuals but also for WAF as a political organisation. In this introduction we highlight what we as editors perceive to be the most important issues for WAF’s activism throughout its history. However, the book has been constructed in such a way that reading all the chapters will itself provide a more pluralistic and contested fl avour of WAF’s politics. Th is introduction outlines the rationale for the book, introduces WAF and its political context, explains the book’s theoretical and methodological framework, and explores some of the themes that have emerged from the activists’ stories.

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Interventions and activities that influence health are often concerned with intangible outcomes that are difficult to value despite their potential significance. Social Return on Investment is an evaluation framework that explores all aspects of change and expresses these in comparable terms. It combines qualitative narratives and quantitative measurements with a financial approach to enable outcomes that can otherwise be overlooked or undervalued to be incorporated appropriately. This article presents Social Return on Investment as an effective tool for supporting the development of a holistic appreciation of how interventions impact on the health and well-being of individuals, communities and societies.

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Los peces cebra son utilizados como modelo biológico para screening primario de extractos de plantas con potencial bioactividad, aprovechando sus similitudes: genética, fisiológica y respuesta farmacológica con los mamíferos. En el estudio se empleó este modelo para valorar la actividad antiinflamatoria de 36 extractos metanólicos de plantas medicinales utilizadas en las provincias de Azuay y Loja (Ecuador). Parte del material vegetal fue recolectado con el aporte de una hierbatera de etnia Saraguro. Los extractos fueron preparados por percolación y su toxicidad fue evaluada en peces cebra en concentraciones variables de 400 a 3,125 μg/ml, determinándose la máxima concentración tolerada para cada uno de ´estos. La actividad antiinflamatoria se evaluó a través del ensayo de migración leucocitaria inducida por lipopolisacárido de Sallmonella typhi. Los extractos de: Cestrum aff. peruvianum, Galinsoga parviflora, Galium sp., Oenothera tetraptera, Peperomia aff. galioides , Passiflora ampullaceae y Ambrosia arborescens, correspondientes al 18,92% de los analizados, mostraron un potencial antiinflamatorio comparable con indometacina y dexametasona; siendo el extracto metanólico de Cestrum aff. peruvianum el más relevante a 50 g/ml. El análisis fitoquímico básico de los extractos se realizó por cromatografía de capa fina, evidenciándose la presencia de saponinas y terpenoidoes como compuestos principales en la mayoría de los extractos.

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Background: One of the global targets for non-communicable diseases is to halt, by 2025, the rise in the age-standardised adult prevalence of diabetes at its 2010 levels. We aimed to estimate worldwide trends in diabetes, how likely it is for countries to achieve the global target, and how changes in prevalence, together with population growth and ageing, are affecting the number of adults with diabetes. Methods: We pooled data from population-based studies that had collected data on diabetes through measurement of its biomarkers. We used a Bayesian hierarchical model to estimate trends in diabetes prevalence - defined as fasting plasma glucose of 7·0 mmol/L or higher, or history of diagnosis with diabetes, or use of insulin or oral hypoglycaemic drugs - in 200 countries and territories in 21 regions, by sex and from 1980 to 2014. We also calculated the posterior probability of meeting the global diabetes target if post-2000 trends continue. Findings: We used data from 751 studies including 4 372 000 adults from 146 of the 200 countries we make estimates for Global age-standardised diabetes prevalence increased from 4·3% (95% credible interval 2·4-7·0) in 1980 to 9·0% (7·2-11·1) in 2014 in men, and from 5·0% (2·9-7·9) to 7·9% (6·4-9·7) in women. The number of adults with diabetes in the world increased from 108 million in 1980 to 422 million in 2014 (28·5% due to the rise in prevalence, 39·7% due to population growth and ageing, and 31·8% due to interaction of these two factors). Age-standardised adult diabetes prevalence in 2014 was lowest in northwestern Europe, and highest in Polynesia and Micronesia, at nearly 25%, followed by Melanesia and the Middle East and north Africa. Between 1980 and 2014 there was little change in age-standardised diabetes prevalence in adult women in continental western Europe, although crude prevalence rose because of ageing of the population. By contrast, age-standardised adult prevalence rose by 15 percentage points in men and women in Polynesia and Micronesia. In 2014, American Samoa had the highest national prevalence of diabetes (>30% in both sexes), with age-standardised adult prevalence also higher than 25% in some other islands in Polynesia and Micronesia. If post-2000 trends continue, the probability of meeting the global target of halting the rise in the prevalence of diabetes by 2025 at the 2010 level worldwide is lower than 1% for men and is 1% for women. Only nine countries for men and 29 countries for women, mostly in western Europe, have a 50% or higher probability of meeting the global target. Interpretation Since 1980, age-standardised diabetes prevalence in adults has increased, or at best remained unchanged, in every country. Together with population growth and ageing, this rise has led to a near quadrupling of the number of adults with diabetes worldwide. The burden of diabetes, both in terms of prevalence and number of adults aff ected, has increased faster in low-income and middle-income countries than in high-income countries.