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Kartik Shanker 《Resonance》2002,7(6):53-66
Marine turtles are known to migrate several thousands of kilometres between their feeding and breeding grounds. These migrations have been studied by the application of metal tags on flippers, with intense monitoring at nesting sites, and opportunistic recovery in offshore waters, providing information on turtle movements. Often, several thousands of tags have been applied with very low levels of recapture. Satellite telemetry is a high-tech, and expensive, method to track turtles during their migration across the open ocean. Molecular genetic techniques have offered ways to track turtles both through space and time. The comparison of genetic haplotypes from different regions makes it possible to study population structure, test theories of natal homing, and even assign feeding populations to nesting sites and vice versa. The study of these haplotypes has also made it possible to look at relationships between species and populations, and study evolutionary biogeography or phylogeography of these animals. 相似文献
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Kartik Shanker 《Resonance》1999,4(7):68-78
Ridleys are unique amongst sea turtles in exhibiting massnesting, when several thousand turtles migrate en masse to their nesting ground to mate and nest simultaneously. Gahirmatha, in Orissa, has the largest sea turtle rookery in the world, with 100,000 to 500,000 turtles nesting there in most years. Mass mortality and fragmentation of the beach led to the failure of the arribada in 1997 and 1998, but more than 200,000 turtles nested on the 2 km long island in Gahirmatha in March, 1999. Despite the occurrence of the arribada, the outlook for the turtles is.bleak since 10000 turtles were drowned as incidental catch in shrimp trawling operations. Over 40,000 turtles have been washed ashore dead since 1994 as a result of drowning in trawl fishing nets. The implementation of existing laws preventing mechanised fishing in near-shore waters and the mandatory use of turtle excluder devices on trawlers would substantially reduce mortality. The consolidation of current conservation efforts is necessary to ensure that this species does not disappear from Indian waters in the near future 相似文献
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Kartik Shanker 《Resonance》1996,1(4):50-57
Sea turtles are a fascinating group of marine reptiles that evolved millions of years ago. They show an intriguing variety of strategies to deal with their aquatic mode of life. Their migrations are legendary, and the mass nesting of the Ridleys is one of nature's most extraordinary spectacles. The eight species are all endangered due to human activities. While some have been exploited for meat, others have suffered due to factors such as pollution. This article details some of the more interesting aspects of their life history and examines their decline in recent times. 相似文献
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Kartik Shanker 《Resonance》1997,2(2):75-82
The Montane Ecosystem, its decline through numerous human acitivities and its relevance to the development of conservation
strategies are described in this article. 相似文献
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Ape language research has been marked by constantly shifting demands made by those who feel that only human beings can acquire language. Kako (1999) continues in this tradition, but his paper marks a significant shift. For Kako concedes that Kanzi possesses rudimentary syntactic skills; but he questions whether Kanzi possesses morphosyntax. Rather than searching, yet again, for some linguistic element that Kanzi has not mastered, we feel it would be more productive, for reasons we explore, to focus now on what exactly Kanzi can do and how this came about. 相似文献
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A de-briefing techique was used to conduct weekly interviews with a university teacher in order to collect information on course planning and monitoring activities. A content analysis of the data showed that most attention was given to talking about students, teaching methods and role, and the process and content of class meetings. The variations in the content of the interviews are discussed in terms of the interaction between the concerns of the teacher and the progress of the course. Applications of the methodology to staff development and further research are outlined. 相似文献