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1.
Current knowledge of the biodiversity of the symbiotic marine siphonostomatoids from South African waters (136 species) is sparse compared to that globally (1 388 species). The difference is especially apparent when taking into account the diversity of fish (more than 2 000 species) and invertebrates (approximately 12 914 species) found in South African waters, all of which are all potential hosts of symbiotic siphonostomatoids. Most reports of symbiotic siphonostomatoids from South African waters are from Chondrichthyes and represent 80% of the currently known families and about 66% of the known genera. Taxonomic studies on the siphonostomatoids also provide information about their morphology, biology, habitat preference and host association, as well as the distribution of species and their associated host taxa. Molecular analysis, especially sequencing, provides additional information on the existence of cryptic species and population structure, but has high financial costs and a very low success rate in DNA isolation and PCR amplification. Reported declines in abundance of piscivorous fish species, for example, as a result of fishing pressure, with possible synergistic effects of environmental changes, and also the reported potential effects of anthropogenic and climate change on the broader coastal biota, may result in the loss of siphonostomatoid species before they can be described. Furthermore, in South Africa, there is a lack of professional taxonomists to study poorly known groups and this situation will not improve while research emphasis remains on commercially important groups and while taxonomic studies are not recognised for their value in research programmes.  相似文献   
2.
This article summarizes briefly the principal conclusions from papers presented in this special issue on marine spatial planning. It identifies potential economic, ecological, and administrative benefits (and costs) that might be realized from the implementation of MSP. Finally, the article summarize lessons learned and identifies future challenges and directions for MSP, including the development of international guidelines for its implementation.  相似文献   
3.
地理学视角下非物质文化遗产的跨地方实践   总被引:2,自引:0,他引:2  
魏雷  朱竑 《地理学报》2022,77(2):492-504
非物质文化遗产不仅是来源于过去的特定区域的传统实践,更是生成于全球化体系中面向未来的现代文化政治和文化经济过程。因此,本文尝试以跨地方性理论为切入点,架构非遗的形成、运作和认同的社会—空间过程,在此基础上使用跨地方聚合的思想重新概念化非遗实践,将其解读为多元主体权力关系中介下,由跨地方异质性要素聚合而成的不稳定的开放系统,以区别于固有对非遗实践“稳定”“以人为中心”和“边界化”的认知。通过分析云南鹤庆银器锻制技艺和摩梭纺织技艺两个案例来呈现非遗实践作为跨地方聚合的过程及特性,以及非遗传承和保护由此所面对的机遇和挑战,呼吁在重视非遗服务于乡村振兴等发展战略的潜力时,要进一步认识非遗实践的跨地方性对本土社区的影响,反思遗产原真性和文化价值与当前非遗实践的关系,强调在非遗全球化生产和消费中保持其与本土认同和本土生计之间的关联。  相似文献   
4.
Chinaˊs urban reforms have brought social progress and development,but a comprehensive national system of social welfare(for example,unemployment insurance,pensions,medical care and public housing)for new migrants from rural areas is lacking.One of the most remarkable changes in Chinese cities in the last decade was a change in so-cial“equality“,with the rise of new poverty both in individual communities and some social groups in urban society.Howev-er,there is little social assistance and public infrastructure for the migrants.Governments or communities or individual should pay attention to the control of new urban poverty and new slums.This paper consider that it is necessary to launch a successful policy,which include mainly:1)accommodating urban growth through low-cost investment projects;2)ur-ban economy depends heavily on successful macroeconomic policy;3)to broaden the three channels linking adjustment to the incidence of urban poverty;4)to restructure urban economic based on the high or new technology;5)to coordi-nate relationship between urban economic growth and environment management for sustainable development of Beijingˊs metropolitan fringe.  相似文献   
5.
我们正在逐步进入大数据时代,大数据开启了一次重大的时代转型,必定会对各个领域中的生存和发展产生重大的影响。本文分析了大数据时代测绘地理信息产业呈现出的新特点、新趋势,阐述了大数据给测绘地理信息产业发展带来的机遇和面临的挑战,提出了推进测绘地理信息产业发展的对策及建议。  相似文献   
6.
Martin Wolf 《Climate Policy》2013,13(6):772-783
Is it possible for all of humanity to enjoy the standards of living of today's high-income countries? What would happen if these limits were reached, perhaps because of climate change or a shortage of natural resources essential to production? How would society manage – or fail to manage – such limits? Notwithstanding the current financial and economic crises, these are perhaps the biggest questions confronting our species (and of a host of other species, who are the victims of our decisions). The article begins by considering the biggest economic event of our lifetimes – the ‘great convergence’ and its implications for the demand for resources. The discussion then turns to a specific limit on our development, climate change, which is different from most other limits, because it involves a global public good: the atmosphere. What such limits might mean for our civilization is discussed. One can persuade people to tackle climate change only if those concerned with the dangers persuade ordinary people that action will not come at the expense of their prosperity.  相似文献   
7.
美、日、欧、俄空间政策调整产生的机遇与挑战   总被引:1,自引:0,他引:1  
冷战结束后,以军事利用为基本特征的美苏空间争夺,已经被以科技创新和经济为中心的综合国力竞争所替代,信息技术和经济全球化的发展,导致外层空间成为具有知识创新要素和技术带动能力的竞争新领域。世界经济大国已经认识空间政策的设计是事关提升综合国力和竞争优势的重大意义。近年来,美、日、欧对空间政策进行了冷战结束后的第一次,全面重大的调整,伴随着体制转型俄罗斯空间政策调整也在展开,面对即将形成的国际空间竞争与合作新的格局和带来新发展机遇,如何清晰地鉴别、定位,对空间政策做出正确的调整,抓住历史机遇应对挑战是摆在中国面前的战略性、全局性和方向性问题。  相似文献   
8.
9.
深层—超深层白云岩储集层: 机遇与挑战*   总被引:1,自引:1,他引:0       下载免费PDF全文
深层—超深层白云岩储集层是未来油气勘探的重要领域和目标,是潜在的优质油气储集体或储集层。查明白云岩的成因、孔隙发育与保存机理以及流体性质与演化路径,建立符合实际地质状况的储集层地质模型,对于预测深层—超深层白云岩储集层的分布规律是非常重要的。疏理了白云岩成因的几个核心问题的现状与发展趋势,指出了白云石化作用模式的演变过程和发展方向,提出了建立深层—超深层白云岩多阶段动态演化模式应考虑的问题。中国三大克拉通盆地(四川盆地、塔里木盆地和鄂尔多斯盆地)深层—超深层赋存丰富的白云岩,并且已经有一些重要的油气发现,为开展深层—超深层白云岩油气勘探提供了好的机遇,但深埋藏、多期构造改造、叠加和复杂的流体演化历史也是此项研究重要的挑战。  相似文献   
10.
正Global Change includes climate change and other environmental changes caused by the joint interaction among various layers of Earth. From the positive side, global change provides new opportunities to human and other living forms on Earth. In the meantime, it creates tremendous challenges and negative impact. At present, the negative impacts have reached all primary processes of the global ecosystem and every aspect of human society, especially causing degradation of the ecosystem. For instance, intensive deforestation causes decline of biodiversity; global warming causes sea level rise and increases  相似文献   
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