952 resultados para rapid change


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Paleoceanographic and paleoenvironmental interpretations based on foraminifera, sedimentary data, radiocarbon dates, and stable isotope measurements were derived from two sections in the Skagerrak: a 115-m-thick Holocene marine section drilled onshore at Skagen near the northernmost tip of Jutland, Denmark, and a 9-m piston core from the Skagerrak, north of Skagen. The foraminiferal data show that arctic-subarctic environments in the deep Skagerrak-Kattegat area were succeeded by boreal conditions at 9.6 ka. This was a result of northward migration of the Atlantic polar front and inflow of warm Atlantic water into the area through the Norwegian Channel. A gradual warming of the water masses after 9.6 ka is indicated by the data. Rare foraminifera and high sedimentation rates are found between approximately 8.6 ka and 7.6 ka at both core locations. The modern foraminiferal assemblages of the area were fully established at 7.6 ka indicating that the modern circulation pattern in the Skagerrak-Kattegat after the opening of the English Channel and the Danish Straits was not established before this date. At 5.5 ka a sudden change to coarser sediments (higher-energy environments) and the appearance of the foraminifer Eoeponidella laesoeensis is recorded in the Skagen core. This indicates a rapid change in the hydrography reflecting altered meteorological and hydrographic conditions in the Skagerrak-Kattegat, including a strengthening of the Jutland Current and increased inflow of North Sea water into the Kattegat. The event is interpreted as a response to cooling at the end of the Holocene climatic optimum in late Atlantic time and possibly reflects a rapid cooling event of North Atlantic surface water masses.

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The paleomagnetic and rock magnetic properties of 51 Jurassic basalts from Ocean Drilling Program (ODP) Hole 801C have been examined. Magnetic properties vary with lithologic composition; alkalic rocks and hydrothermally-altered tholeiites are much weaker in intensity and generally contain higher coercivity magnetic components than the older and less-altered tholeiites at the base of the hole. For the entire column, the Jurassic basalts have an average initial natural remanent magnetization (NRM) intensity of approximately 1.24 A/m and average median destructive fields (MDF) of 8.31 mT. These values and the mean Koenigsberger ratio of 1.7 are very similar to results obtained for Jurassic basalts from the Atlantic (DSDP Leg 76). The similarities suggest that the basalts of both sites and their remanence characteristics are representative of Jurassic oceanic crust. The most profound discovery in these samples was the presence of 5 inclination zones, each showing consistent positive (or negative) polarity opposite the overlying and underlying polarity bands. We interpret these to represent a record of change in polarity of the EarthÆs magnetic field and, because of the large number over such a short interval (60 m) of crust, we assert that the rapid change in polarity during the Jurassic is the probable reason behind the origin of the Jurassic Quiet Zone.

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Structure and composition of sub-surface bottom sediments from the southwest Barents Sea have been under study. The study has revealed heterogeneity of sediment structure resulted from temporal irregularity and variability of sedimentation processes. The study of the heavy minerals from 0.1-0.01 mm grain size fraction has shown prevalence of green hornblende, epidote, garnet, and ilmenite in all types of sediments; these minerals are the basis of terrigenous-mineralogical province. At the same time in different areas local terrigenous-mineralogical associations have been identified. Clay mineral composition of in the sediments was quite uniform: biotite, chlorite, hydromica, smectite. Despite this, a number of features indicating initial stages of clay mineral transformation has been identified. Differences in material composition and structure of the studied sediments are associated with rapid change in paleogeographic situation on the land - ice cover melting on the Kola Peninsula and subsequent Holocene climatic situation.

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Structure and composition of sub-surface bottom sediments from the southwest Barents Sea have been under study. The study has revealed heterogeneity of sediment structure resulted from temporal irregularity and variability of sedimentation processes. The study of the heavy minerals from 0.1-0.01 mm grain size fraction has shown prevalence of green hornblende, epidote, garnet, and ilmenite in all types of sediments; these minerals are the basis of terrigenous-mineralogical province. At the same time in different areas local terrigenous-mineralogical associations have been identified. Clay mineral composition of in the sediments was quite uniform: biotite, chlorite, hydromica, smectite. Despite this, a number of features indicating initial stages of clay mineral transformation has been identified. Differences in material composition and structure of the studied sediments are associated with rapid change in paleogeographic situation on the land - ice cover melting on the Kola Peninsula and subsequent Holocene climatic situation.

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Presented analysis of human and fly life tables proves that with the specified accuracy their entire survival and mortality curves are uniquely determined by a single point (e.g., by the birth mortality q0), according to the law, which is universal for species as remote as humans and flies. Mortality at any age decreases with the birth mortality q0. According to life tables, in the narrow vicinity of a certain q0 value (which is the same for all animals of a given species, independent of their living conditions), the curves change very rapidly and nearly simultaneously for an entire population of different ages. The change is the largest in old age. Because probability to survive to the mean reproductive age quantifies biological fitness and evolution, its universal rapid change with q0 (which changes with living conditions) manifests a new kind of an evolutionary spurt of an entire population. Agreement between theoretical and life table data is explicitly seen in the figures. Analysis of the data on basic metabolism reduces it to the maximal mean lifespan (for animals from invertebrates to mammals), or to the maximal mean fission time (for bacteria), and universally scales them with the total number of body atoms only. Phenomenological origin of this unification and universality of metabolism, survival, and evolution is suggested. Their implications and challenges are discussed.

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Cultural inheritance can be considered as a mechanism of adaptation made possible by communication, which has reached its greatest development in humans and can allow long-term conservation or rapid change of culturally transmissible traits depending on circumstances and needs. Conservativeness/flexibility is largely modulated by mechanisms of sociocultural transmission. An analysis was carried out by testing the fit of three models to 47 cultural traits (classified in six groups) in 277 African societies. Model A (demic diffusion) is conservation over generations, as shown by correlations of cultural traits with language, used as a measure of historical connection. Model B (environmental adaptation) is measured by correlation to the natural environment. Model C (cultural diffusion) is the spread to neighbors by social contact in an epidemic-like fashion and was tested by measuring the tightness of geographic clustering of the traits. Most traits examined, in particular those affecting family structure and kinship, showed great conservation over generations, as shown by the fit of model A. They are most probably transmitted by family members. This is in agreement with the theoretical demonstration that cultural transmission in the family (vertical) is the most conservative one. Some traits show environmental effects, indicating the importance of adaptation to physical environment. Only a few of the 47 traits showed tight geographic clustering indicating that their spread to nearest neighbors follows model C, as is usually the case for transmission among unrelated people (called horizontal transmission).

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O jacaré-de-papo (Caiman latirostris) é considerado um crocodiliano de médio porte que apresenta uma ampla distribuição latitudinal na América do Sul. Possivelmente a espécie possui a situação mais complexa entre os crocodilianos brasileiros quanto ao aspecto da conservação, basicamente porque suas populações encontram-se fragmentadas em grande parte de sua área de distribuição original e por utilizarem áreas com fortes atividades antrópicas. Embora a espécie possua aparentemente um processo adaptativo frente a estas pressões, um aspecto fisiológico pode ainda sofrer rápida alteração quando submetido a elas: o estado sanitário. Desta maneira, este estudo objetivou determinar o estado sanitário do maior predador aquático, utilizando duas áreas distintas no Estado de São Paulo, através da determinação dos perfis hematológicos e bioquímicos do sangue, além da caracterização da microbiota oral, servindo de modelo à conservação da espécie em ambientes alterados. No primeiro capítulo foram determinados o perfil hematológico e bioquímico do sangue utilizando-se 29 indivíduos (19 machos e 10 fêmeas) capturados em Angatuba e 11 indivíduos (2 machos, 4 fêmeas e 5 filhotes) capturados em Cubatão. Diferenças estatísticas significativas foram encontradas nos valores de creatinina na comparação entre fêmeas de ambas as áreas de estudo (p = 0,033) e nos valores de alanina aminotransferase (p = 0,003), hemácias (p = 0,034), hemoglobina (p = 0,049) e volume corpuscular médio (p = 0,027) quando da comparação entre sexos. No segundo capítulo determinou-se a microbiota oral destes animais através do isolamento, identificação e caracterização bacteriana, em conjunto com o teste de perfil de susceptibilidade aos antimicrobianos. Foram determinados 14 diferentes tipos de bactérias na área de Angatuba, sendo uma classificada como baciliforme aeróbio Gram-positivo, uma como bacilo Gram-negativo e 12 classificadas como Enterobactérias Gram-negativas. Na área de Cubatão foram isolados cinco tipos de bactérias, sendo quatro classificadas como Enterobactérias Gram-negativas e uma como baciliforme aeróbio Gram-positivo. Considerando que o uso de antimicrobianos é um processo primário no tratamento de animais e pessoas, principalmente nos casos que envolvam infecções provocadas pela interação homem x animais, para ambas as áreas de estudo, as quinolonas Enrofloxacina e Norfloxacina, além do aminoglicosídeo Gentamicina, foram os antimicrobianos que apresentaram os menores índices de resistência frente aos isolados testados.

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During the 2008 financial crisis, the G20 was hastily elevated to ‘global economic steering committee’. In the early stages of the crisis, the G20 was an effective forum for crisis containment. As the crisis has eased, however, the G20 has lost both direction and momentum. Governments and policymakers have felt less need to act in unison and have rather refocused on their national agendas, as is their duty and primary function. However, effective global governance is needed permanently, not just in crisis times. It is desirable to have more representative and effective global governance that, among other things, is equipped to prevent crises rather than just react to them. In an environment of rapid change in global patterns of trade and wealth creation, a new revamped (but highly representative) grouping should be created within the G20, to provide leadership on key economic policy matters. Euro-area members should give up their individual seats in this G7+, allowing room for China and other large emerging economies. Without euro-area countries taking such a step, it would be impossible to reconcile effectiveness and representation in this new G7+, which would take charge of decision making on global economic imbalances, financial and monetary issues. All existing G20 countries, including individual euro-area countries, would however remain in the G20, which could potentially expand and would remain the prime forum for discussion on all remaining matters at global level.

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Sediment cores from the Amazon deep sea fan recovered during R/V Meteor cruise 16-2 show in detail the modern areal distribution of sedimentary organic carbon, stable organic carbon isotopes of the organic matter (OM), as well as variations in the depositional processes. In addition, we studied up to 300 m long drilled sediment records recovered during ODP Leg 155 which allow evaluation of temporal variations on the Amazon fan. Our results reveal new evidence for a very rapid change of fan depositional processes and organic carbon source at times of sea-level change over the middle and lower Amazon fan. To estimate the amount of terrestrial organic carbon stored in sediments from the last glacial in the Amazon fan we used stable organic carbon isotopes of the OM (delta13Corg), organic carbon content (Corg), and age models based on oxygen isotopes, faunal data, and magnetic excursions. Following our results, the organic carbon accumulation on the Amazon deep sea fan is controlled by glacio-eustatic sea-level oscillations. Interglacial sea-level high stand sediments are dominated by marine OM whereas during glacial sea-level low stands terrestrial organic carbon is transported beyond the continental shelf through the Amazon canyon and deposited directly onto the Amazon deep sea fan. Glacial sediments of the Amazon fan stored approximately 73*10**15 g terrestrial Corg in 20,000 years or 3.7*10**12 g terrestrial Corg/yr (equivalent to 7-12% of the riverine organic carbon discharge; assuming constant paleo discharge), which is about the same amount of terrestrial organic carbon as deposited on the Amazon shelf today (3.1*10**12 g terrestrial Corg/yr or 6-10% of the modern riverine organic carbon discharge).

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The Paleocene/Eocene Thermal Maximum (PETM) was a transient interval of global warming ~55 m.y. ago associated with transformation of ecosystems and changes in carbon cycling. The event was caused by the input of massive amounts of CO2 or CH4 to the ocean-atmosphere system. Rapid shoaling of the lysocline and calcite compensation depth (CCD) is a predicted response of CO2 or CH4 input; however, the extent of this shoaling is poorly constrained. Investigation of Ocean Drilling Program (ODP) Sites 1209-1212 at Shatsky Rise, which lies along a depth transect, suggests a minimum lysocline shoaling of ~500 m in the tropical Pacific Ocean during the PETM. The sites also show evidence of CaCO3 dissolution within the sediment column, carbonate "burn-down" below the level of the carbon isotope excursion, and a predicted response to a rapid change in deepwater carbonate saturation. Close examination of several foraminiferal preservation proxies (i.e., fragmentation, benthic/planktonic foraminiferal ratios, coarse fraction, and CaCO3 content) and observations of foraminifers reveal that increased fragmentation levels most reliably predict intervals with visually impoverished foraminiferal preservation as a result of dissolution. Low CaCO3 content and high benthic/planktonic ratios also mirror intervals of poorest preservation.

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Modern erosion of the Himalaya, the world's largest mountain range, transfers huge dissolved and particulate loads to the ocean. It plays an important role in the long-term global carbon cycle, mostly through enhanced organic carbon burial in the Bengal Fan. To understand the role of past Himalayan erosion, the influence of changing climate and tectonic on erosion must be determined. Here we use a 12 Myr sedimentary record from the distal Bengal Fan (Deep Sea Drilling Project Site 218) to reconstruct the Mio-Pliocene history of Himalayan erosion. We use carbon stable isotopes (d13C) of bulk organic matter as paleo-environmental proxy and stratigraphic tool. Multi-isotopic - Sr, Nd and Os - data are used as proxies for the source of the sediments deposited in the Bengal Fan over time. d13C values of bulk organic matter shift dramatically towards less depleted values, revealing the widespread Late Miocene (ca. 7.4 Ma) expansion of C4 plants in the basin. Sr, Nd and Os isotopic compositions indicate a rather stable erosion pattern in the Himalaya range during the past 12 Myr. This supports the existence of a strong connection between the southern Tibetan plateau and the Bengal Fan. The tectonic evolution of the Himalaya range and Southern Tibet seems to have been unable to produce large re-organisation of the drainage system. Moreover, our data do not suggest a rapid change of the altitude of the southern Tibetan plateau during the past 12 Myr. Variations in Sr and Nd isotopic compositions around the late Miocene expansion of C4 plants are suggestive of a relative increase in the erosion of High Himalaya Crystalline rock (i.e. a simultaneous reduction of both Transhimalayan batholiths and Lesser Himalaya relative contributions). This could be related to an increase in aridity as suggested by the ecological and sedimentological changes at that time. A reversed trend in Sr and Nd isotopic compositions is observed at the Plio-Pleistocene transition that is likely related to higher precipitation and the development of glaciers in the Himalaya. These almost synchronous moderate changes in erosion pattern and climate changes during the late Miocene and at the Plio-Pleistocene transition support the notion of a dominant control of climate on Himalayan erosion during this time period. However, stable erosion regime during the Pleistocene is suggestive of a limited influence of the glacier development on Himalayan erosion.

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This paper examines trends in the practice of Operations Management and in teaching the field in major Business Schools. Operations Management has been defined as the design and management of transformation processes that create value for society. The operations function is the one function directly involved in that transformation, and hence is directly responsible for the activities that justify the existence of the firm, both economically and as a value-creating organization in society. The top rated schools in Operations Management are the top-rated research-intensive Business Schools in the world. Operations Management is an area that has been undergoing rapid change in response to changes in business practices worldwide. It is at the heart of changes of which the AACSB report Management Education at Risk, August 2002 (p 20), comments of Business Schools in general: ‘With regard to global relevance (of Business Schools), the complex opportunities and challenges that emanate from the world scope of operations, outsourcing, supply chains, partnerships, and financial and consumer markets – all linked in real time through the Internet – are not reflected adequately in curricula and learning approaches.’ Products, and even services, depend increasingly on advanced technology. This is true globally and especially so for countries in South East and East Asia, from which Australian Universities draw a significant number of students. Services operations management has become much more important, while there are both educational and industrial needs in management science or operations research.

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Ontologies have become widely accepted as the main method for representing knowledge in Knowledge Management (KM) applica-tions. Given the continuous and rapid change and dynamic nature of knowledge in all fields, automated methods for construct-ing ontologies are of great importance. All ontologies or taxonomies currently in use have been hand built and require consider-able manpower to keep up to date. Taxono-mies are less logically rigorous than ontolo-gies, and in this paper we consider the re-quirements for a system which automatically constructed taxonomies. There are a number of potentially useful methods for construct-ing hierarchically organised concepts from a collection of texts and there are a number of automatic methods which permit one to as-sociate one word with another. The impor-tant issue for the successful development of this research area is to identify techniques for labelling the relation between two candi-date terms, if one exists. We consider a number of possible approaches and argue that the majority are unsuitable for our re-quirements.