13 resultados para Evaporation over Indian Ocean

em Deakin Research Online - Australia


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Leatherback turtles Dermochelys coriacea spend most of their life in oceanic environments, whose physical and biological characteristics are primarily forged by sea current circulation. Water mass movements can mechanically act on swimming turtles, thus determining their routes, and can differentially distribute their planktonic prey. By integrating satellite tracking data with contemporaneous remote-sensing information, we analysed the post-nesting journeys of 9 leatherbacks with respect to oceanographic surface conditions. Tracked turtles showed large variations in migration routes and in final destinations, apparently without heading for specific foraging areas. Their complex tracks spread over wide regions around South Africa. Leatherbacks were greatly influenced by the currents encountered during their movements, with their trajectories displaying curves or revolutions in the presence of (and in accordance with) rotating water masses. An impressive similarity was observed between large parts of the turtle routes and those of surface drifters tracked in the same regions. Finally, leatherbacks remained associated for long periods with specific oceanographic features, which most probably offered them profitable foraging opportunities. These results agree with previous findings in showing a strong influence of oceanic currents and mesoscale features on the movements of South African leatherbacks, and additionally identify the role of current-related features in causing the observed route variability and in determining high-quality foraging hotspots for leatherbacks moving in the ocean.

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The article reviews the book "Foreign Direct Investment in Europe: A Changing Landscape," edited by Klaus Liebscher, Josef Christl, Peter Mooslechner, and Doris Ritzberger-Grünwald, and "International Business Marketing in Emerging Country Markets: The Third Wave of Internationalization of Firms," by Hans Jansson.

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Comparing humpback whale song from different breeding assemblages can reveal similarities in song due to acoustically interacting males, and therefore indirectly test whether males from different breeding sites are mixing. Northern Hemisphere song comparisons illustrated that whales within ocean basins share similar songs and are subpopulations within a larger population, whereas whales in different ocean basins are isolated populations and therefore do not share songs. During the 2006 breeding season, recordings were collected in Madagascar and Western Australia, and were compared visually plus aurally. Both regions shared one theme, whereas each region had four and six private themes, respectively. This study had a substantially low number of shared themes. The co-occurrence of one theme was interpreted as an indication of limited exchange between these breeding assemblages, and we speculate that limited song similarity is due to inter-oceanic interactions. Male(s) from an Indian Ocean breeding group could be exposed to novel song when they geographically overlap, and acoustically interact, with males from a different ocean basin. Novel song could induce rapid temporal changes as new song content is incorporated, thereby minimizing song similarities between that breeding group and other Indian Ocean breeding groups that were not exposed to the novel song.

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The study is focused on an analysis of the major diplomatic documents from the mid eighteenth century to the present as regards Sri Lanka, or Ceylon as it was known till 1972. The objectives of the study are to identify the issues underlying these diplomatic documents. These include the political and strategic factors and other subsidiary issues like trade and commerce relevant at the time these treaties, agreements, and proposed treaties were formulated. It is also a geopolitical study as it relates to Sri Lanka's geographical position in the Indian Ocean, and her possession of the Trincomalee Harbour on its east coast, which is one of the great natural harbours of the world. Over the centuries this harbour has had significant strategic value for naval deployments. The case study of the eighteenth and nineteenth centuries studies the diplomatic documents against the political and strategic background for the French Revolution and actions of Napoleon, and the Anglo/French rivalry, spreading from Europe to North America and Asia. In the twentieth century the environment for studying the place of Sri Lanka in the Indian Ocean was created by the Russian Revolution, the failure to keep the peace of Versailles after World War I, the conflict and horrors of World War II which led to the disintegration of European colonial empires in Asia and Africa, and the tensions generated by the Cold War. A study of the documents would reveal that in international relations what matters is the ability of a party to promote its interests, and this depends on its power. This realist approach contrasts to the idealist approach where policies are based on moral and ethical principles. For the realist the states should follow to protect their interests and to survive. To achieve this is to strive for a ‘balance of power’. To do so is to form a favourable alliance system. As the documents examined cover a period from the mid-eighteenth century to the later part of the twentieth century, they reflect the changing technologies that have had an influence on naval and military matters. For example, this period witnessed great changes in technology of energy utilized to propel warships, from wind, to steam, to fuel and finally to nuclear power. These changes had an influence in determining strategic policies involving weapon systems and communications within a global and regional setting. The period covered was the beginning of the process described a ‘globalisation’. Its idea is not unique to this century; there were many attempts, in various times of history, to integrate societies within a global context. Viewed in this light, the Anglo-French rivalry of the eighteenth and nineteenth centuries was the indication of a global naval strategy, in which Sri Lanka was a major factor in the Indian Ocean region. This process was associated with the phenomena called the ‘expansion of Europe’. It covered all the oceans of the world and in the nineteenth and twentieth centuries led to the founding of the largest maritime empire the world has ever seen: The British Empire. After World War I, the British naval strength (the basis of the British Empire) and her consequent position as a great power, was challenged by other powers like the United States of America and Japan. After World War II, the US Navy was supreme: and there was a close alliance between Britain and the USA. The strength of the US/British alliance was based on the navy and its bases, which were spread throughout the globe; to project power, and act as deterrence and balancing force. Sri Lanka, due to her strategic position, was a part of this evolving process, and was tied to a global strategy (with its regional connotations) from the eighteenth century to the present.

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Eocene ocean currents and prevailing winds correlate with over-water dispersals of terrestrial mammals from Africa to Madagascar. Since the Early Miocene (about 23 Ma), these currents flowed in the reverse direction, from the Indian Ocean towards Africa. The Comoro Islands are equidistant between Africa and Madagascar and support an endemic land vertebrate fauna that shares recent ancestry predominantly with Madagascar. We examined whether gene flow in two Miniopterus bat species endemic to the Comoros and Madagascar correlates with the direction of current winds, using uni- and bi-parentally inherited markers with different evolutionary rates. Coalescence-based analyses of mitochondrial matrilines support a Pleistocene (approximately 180 000 years ago) colonization event from Madagascar west to the Comoros (distance: 300 km) in the predicted direction. However, nuclear microsatellites show that more recent gene flow is restricted to a few individuals flying against the wind, from Grande Comore to Anjouan (distance: 80 km).

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Climate change is perhaps the most pressing and urgent environmental issue facing the world today. However our ability to predict and quantify the consequences of this change is severely limited by the paucity of in situ oceanographic measurements. Marine animals equipped with sophisticated oceanographic data loggers to study their behavior offer one solution to this problem because marine animals range widely across the world’s ocean basins and visit remote and often inaccessible locations. However, unlike the information being collected from conventional oceanographic sensing equipment, which has been validated, the data collected from instruments deployed on marine animals over long periods has not. This is the first long-term study to validate in situ oceanographic data collected by animal oceanographers. We compared the ocean temperatures collected by leatherback turtles (Dermochelys coriacea) in the Atlantic Ocean with the ARGO network of ocean floats and could find no systematic errors that could be ascribed to sensor instability. Animal-borne sensors allowed water temperature to be monitored across a range of depths, over entire ocean basins, and, importantly, over long periods and so will play a key role in assessing global climate change through improved monitoring of global temperatures. This finding is especially pertinent given recent international calls for the development and implementation of a comprehensive Earth observation system (see http://iwgeo.ssc.nasa.gov/documents.asp?s=review) that includes the use of novel techniques for monitoring and understanding ocean and climate interactions to address strategic environmental and societal needs.

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Large marine protected areas (MPAs), each hundreds of thousands of square kilometers, have been set up by governments around the world over the last decade as part of efforts to reduce ocean biodiversity declines, yet their efficacy is hotly debated. The Chagos Archipelago MPA (640,000 km2) (Indian Ocean) lies at the heart of this debate. We conducted the first satellite tracking of a migratory species, the green turtle (Chelonia mydas), within the MPA and assessed the species' use of protected versus unprotected areas. We developed an approach to estimate length of residence within the MPA that may have utility across migratory taxa including tuna and sharks. We recorded the longest ever published migration for an adult cheloniid turtle (3979 km). Seven of 8 tracked individuals migrated to distant foraging grounds, often ≥1000 km outside the MPA. One turtle traveled to foraging grounds within the MPA. Thus, networks of small MPAs, developed synergistically with larger MPAs, may increase the amount of time migrating species spend within protected areas. The MPA will protect turtles during the breeding season and will protect some turtles on their foraging grounds within the MPA and others during the first part of their long-distance postbreeding oceanic migrations. International cooperation will be needed to develop the network of small MPAs needed to supplement the Chagos Archipelago MPA.

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Over recent years, a major breakthrough in marine animal tracking has occurred with the advent of Fastloc-GPS that provides highly accurate location data even for animals that only surface briefly such as sea turtles, marine mammals and penguins. We assessed the accuracy of Fastloc-GPS locations using fixed trials of tags in which >45 000 locations were obtained. Procedures for determining the speed of travel and heading were developed by simulating tracks and then adding Fastloc-GPS location errors. The levels of detail achievable for speed and heading estimates were illustrated by using empirical Fastloc-GPS data for a green turtle (Chelonia mydas, Linnaeus, 1758) travelling over 3000 km across the Indian Ocean. The accuracy of Fastloc-GPS locations varied as a function of the number of GPS satellites used in the location calculation. For example, when Fastloc-GPS locations were calculated using 4 GPS satellites, 50% of locations were within 36 m and 95% within 724 m of the true position. These values improved to 18 and 70 m, respectively, when 6 satellites were used. Simulations indicated that for animals travelling around 2·5 km h-1 (e.g. turtles, penguins and seals) and depending on the number of satellites used in the location calculation, robust speed and heading estimates would usually be obtained for locations only 1-6 h apart. Fastloc-GPS accuracy is several orders of magnitude better that conventional Argos tracking or light-based geolocation and consequently will allow new insights into small-scale movement patterns of marine animals.

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The Cocos (Keeling) Islands are a remote Australian territory in the Indian Ocean and arehome to the Cocos Malay people, who have developed a distinct dialect. It waspredicted over 30 years ago that the Cocos Malay language faced extinction, perhapseven within the timeframe of one generation. Two possible threats to the Cocos Malaylanguage were identified. It was felt that English, as the language of power, may replacethe Cocos Malay language. The other possibility was language convergence, whereCocos Malay would be subsumed by another, larger Malay dialect. With these issues inmind, I explore developments in the Cocos Malay language since the Islands’ fullintegration with Australia in 1984. Drawing from extensive ethnographic work andlinguistic research into Cocos Malay I also refer to the work of other researchers toanalyse how the Cocos Malay language has developed over the past 30 years, in a timeof great social change. I argue that integration with Australia and attempts atassimilation have resulted in social dynamics where Cocos Malay language remains adefining marker of Cocos Malay identity positioning. In this social environment, CocosMalay therefore remains viable and, despite language change, does not face immediateextinction.