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41.
In 1982, for the first time since OPEC was founded in 1961, its production was surpassed by the non-OPEC countries in the world excluding the centrally planned economies. In that year, for the world as a whole, OPEC provided 35% of the oil consumed. The decline was brought about by a decrease in consumption and by a marked increase in production from non-OPEC sources. It is expected that non-OPEC producers will have the capacity to meet more than half of the world's oil requirements until the early 1990s, at which time OPEC producers will again assume the role of providing over 50% of the world's oil.  相似文献   
42.
Seasonal changes in biochemical composition of tissues are compared in a shallow inshore and deeper offshore population of the seastarSclerasterias mollis (Hutton, 1872) on the Otago shelf, New Zealand, from 1985 to 1986. The biochemical composition of the body wall, gonads and pyloric caeca of the two populations did not differ greatly, even though reproductive output and nutrient storage of reserves were consistently higher in the offshore population. The biochemical composition of the ovaries and testes differed. High levels of carbohydrate and lipid were maintained in the ovaries from the commencement of vitellogenesis until spawning occurred. The testes had higher ash levels during spermatogenesis. During the annual reproductive cycle, an inverse relationship in the carbohydrate levels between the ovary and the pyloric caeca suggests nutrient transfer from the pyloric caeca to the gonads during gametogenesis. Annual changes in biochemical composition indicate that the body wall is also used for nutrient storage.  相似文献   
43.
Ecological Compensation in Dutch Highway Planning   总被引:13,自引:0,他引:13  
The ecological compensation principle was introduced by the Dutch government in 1993. This principle is designed to enhance the input of nature conservation interests in decision-making on large-scale development projects and to counterbalance the ecological impacts of such developments when implemented. This article evaluates the application of the Dutch compensation principle in highway planning. Six current highway projects reveal consistent implementation of this principle, although provincial policies on compensation and a national method for identifying compensation measures are still under development. As the planning process has not yet been completed for all the projects, no general conclusions can be drawn on the impact of the compensation principle on highway decision-making. Nevertheless, several examples show that the principle stimulates project initiators to develop alternative routes or route sections in order to avoid or reduce ecological impacts and the need for coherent compensation measures. If the compensation principle is to be properly implemented in the context of highway planning, particular attention should be paid to the following aspects: (1) sequential assessment of overall project legitimacy and the necessity of intersecting protected areas and compensation measures, (2) the initiator's attempts to avoid and mitigate ecological impacts in developing alternative routes prior to compensation for impacts, and (3) the role of uncertain ecological impacts in identifying compensation measures, especially those concerning habitat isolation.  相似文献   
44.
Integrated coastal zone management (ICZM) has evolved as a key mechanism for the delivery of sustainable development objectives within coastal regions. Yet, despite significant advancements in ICZM application over recent years, one of the most noticeable weaknesses of ICZM performance has been a failure to adequately account for the existence of socio‐economic concerns. This information deficiency is particularly apparent in Scotland. Despite significant progress in the promotion of ICZM, Scottish experiences have been characterized by a focus upon sectoral policy co‐ordination and environmental dimensions of sustainability. This paper provides an evaluation of both socio‐economic conditions and processes which impact upon coastal communities in Scotland and considers how such issues can be accounted for within future coastal management debates.  相似文献   
45.
不同植被对工业污染区盐渍土的改良效果   总被引:1,自引:0,他引:1  
以包头市西郊工业污染区盐渍化弃耕地为对象,研究了不同植被对土壤水盐动态和体积质量的影响。研究表明,造林后使林地内草本植物得到较快恢复,且归还土壤的枯落物比木本植物多,改良盐渍土壤和促进脱盐的作用较好;随植被盖度增加,盐渍土土壤含盐量和体积质量降低,盐渍土性状逐步改善。因此,在实施以耐盐树种造林为先导的工业污染区盐渍土恢复植被工程时,应适当降低造林密度,以利于林地内草本植物的恢复和建立林草复合植被,提高工业污染区盐渍土的生物治理效果。  相似文献   
46.
Preventing groundwater contamination is vastly cheaper than remediation. Recognizing this, attention in water and land management agencies in North America increasingly turn to groundwater protection. Local agencies, such as municipalities and watershed management districts, are vital to successful groundwater protection, but they face daunting challenges. In the United States, senior governments have recognized these challenges and provide considerable support for local agencies. In Ontario, Canada, local agencies are, to a much greater extent, on their own. The aims in this paper are to analyze factors that shape local capacity for groundwater protection, focusing on Ontario, and to recommend avenues for capacity building. Interrelationships among five dimensions of capacity (technical, financial, institutional, social, and political) are explored through an analysis of three smaller Ontario communities: City of Guelph (population 93,400), Town of Orangeville (population 22,188), and Town of Erin (population 11,000). Size clearly influences capacity for groundwater protection. However, other considerations unrelated to size appear to be as important. These other factors include the ability to form horizontal and vertical linkages with external agencies, political leadership and commitment, and citizen involvement. Thus, smaller communities in Ontario (and other jurisdictions with limited senior government support) would do well to focus on these areas at the same time as they develop their technical, financial, and institutional capacity.  相似文献   
47.
This paper examines the changing trends in world tin demand for the period 1962–1985. In the early 1970s tin production peaked, and has since declined. The reasons for the decline are examined in terms of changes in product composition of income (i.e. mix of goods and services), changes in material composition of products, decline in gross domestic investment and the rising price of tin.  相似文献   
48.
The occurrence of various visible symptoms of foliar injury was assessed on a 5-point scale for each of the species. There was a distinct increase in the incidence of most types of injury in plant material which has been exposed to pH 2.5 acid fog. No clear pH-related trend in foliar injury occurred in plants exposed to acid fog at pH 3.5, pH 4.5 and pH 5.6, indicating that a threshold for a range of different types of visible injury may exist between pH 2.5 and pH 3.5 for all four species.  相似文献   
49.
The European Water framework directive (WFD) is probably the most important environmental management directive that has been enacted over the last decade in the European Union. The directive aims at achieving an overall good ecological status in all European water bodies. In this article, we discuss the implementation steps of the WFD and their implications for environmental engineering practice while focusing on rivers as the main receiving waters. Arising challenges for engineers and scientists are seen in the quantitative assessment of water quality, where standardized systems are needed to estimate the biological status. This is equally of concern in engineering planning, where the prediction of ecological impacts is required. Studies dealing with both classification and prediction of the ecological water quality are reviewed. Further, the combined emission–water quality approach is discussed. Common understanding of this combined approach is to apply the most stringent of either water quality or emission standard to a certain case. In contrast, for example, the Austrian water act enables the application of only the water quality based approach - at least on a temporary basis.  相似文献   
50.
Local employees in foreign business subsidiaries could learn new work values from the parent organizational culture through a process of organizational acculturation. As this is a new concept in academic research, it is important to explore organizational acculturation and its ramifications, especially since it may be used as a strategy of cultural control applied by the parent organization. Following a discussion of the theoretical foundation of this concept, the consequences of organizational acculturation are exemplified by an investigation of middle managers in Singapore. The study was undertaken in two stages. The first stage included a comparison of work values of Singaporean managers, employed by Swedish companies in Singapore, and those of a control group of Singaporean managers, not employed by Swedish companies. In the second stage, work values of managers in Singapore and Sweden were compared. Our results imply that some Swedish work values had been adopted, suggesting that the local managers had experienced organizational acculturation. Practical implications and possible further research are discussed.  相似文献   
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