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The interactions of nature and society are intimately reflected in the degradation of the vast, yet diverse, landscapes and ecosystems of arid western China. The development of agriculture, especially irrigation, has altered rivers, soils and ecosystems so much that major ecological rehabilitation and restoration efforts have been needed since 1950. The catchments of the Tarim River in southern Xinjiang (the Tarim Basin) and of the Black River (Hei He) in Gansu Province and western Inner Mongolia provide examples of the benefits, difficulties and conflicts involved in dryland water management. In the early stages of the human development of these catchments, agriculture depending on irrigation using water from these inland rivers was encouraged. The over‐exploitation of these water resources led to such ecological problems as desiccation of lakes, drying out of rivers, degradation of soils and vegetation and lowering of groundwater levels, with consequent environmental and economic impacts. Since 1990 several high‐cost, national projects to re‐establish ecosystems have been initiated. Water is now released from dams in the headwaters of the rivers in order to restore water flows to the dried out lake basins. Such schemes have inevitably led to social problems and difficulties for the people who depended on the water from the dams for local irrigation. The contrasts in adjustments and attitudes over the use of water for agriculture and other economic activities, as opposed to schemes of restoration of ecosystems and ecological engineering, stem largely from two issues; inconsistent provision of information from the scientific community, and differing ideologies, namely environmental protection versus economic development. 相似文献
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In the immediate wake of the 1996 Australian federal elections pundits variously attributed the ALP's defeat to the loss of its 'heartlands', to the party's failure in government to retain the support of 'battlers', or even to the collapse of Labor's traditional blue-collar 'core' constituency. Using Queensland as a case-study, and drawing on aggregate as well as survey data, this research note provides support for claims that Labor's traditional support base deserted it in 1996. 相似文献
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NICHOLAS PAUL CHANDLER DAVID MacGREGOR FYFE 《International Journal of Osteoarchaeology》1997,7(1):11-17
The radiographs of 43 skulls recovered from a 4000-year-old site in Central Thailand were examined for changes in the pulp chamber and root canals of teeth. Eleven specimens aged between 8 and 40 years featured marked root canal radiopacities not consistent with the appearance of dentine. Scanning electron microscopy and electron microprobe analysis revealed the presence of crystals of almost pure calcium. The crystals had developed post-mortem, with the likely source of the mineral being sea shells which were abundant at the place of burial. © 1997 by John Wiley & Sons, Ltd. 相似文献
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The history of British defence reviews has been one of repeated disappointment: a cycle in which policy failure is followed by a period of inertia, giving way to an attempt at a new policy framework which is then misimplemented by the defence leadership. Each failed defence review therefore sows the seeds of its successor. With this in mind, in 2010 the new coalition government embarked upon an altogether more ambitious exercise: a strategy review comprising a National Security Strategy and a Strategic Defence and Security Review. This article suggests, nevertheless, not only that the 2010 strategy review looks likely to follow past performance, but also that it is coming unstuck at an unprecedented rate. This is a pity since the 2010 review had much to commend it, not least the adoption of a risk‐based approach to security and defence policy‐making. What is the explanation for this outcome? Is it that the British have, as some have suggested, lost the ability to ‘do strategy’, if ever they had it? The authors offer a more nuanced understanding of the policy process and argue that the coalition government in fact has a very clear and deliberate strategy—that of national economic recovery. Yet the coalition government cannot allow national defence and security to fail. The authors conclude with an assessment of the options open to the defence leadership as they seek to address the failing 2010 strategy review and suggest a variety of indicators which will demonstrate the intent and seriousness of the political, official and military leadership of the Ministry of Defence. 相似文献