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黑河流域生态环境脆弱性研究 总被引：3，自引：0，他引：3
黑河流域地处河西走廊中部，其特殊的气候条件和地貌特征对当地生态环境起主要的控制性作用，加之人类活动的影响，植被、土壤和水等环境都表现出不同程度的脆弱性特征．具体表现为土地沙化、土壤盐渍化、草场退化、水资源减少、植被单一、生物多样性丧失等．从恢复生态学的观点出发，探索维持生态系统稳定性和恢复重建机制． 相似文献
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生态环境建设的内涵与配置 总被引：2，自引：1，他引：2
该文从生态环境建设的概念入手,深入分析了生态环境建设的内涵.指出,生态环境建设的实质是水资源、土地资源、气候资源、生物资源等再生自然资源的保护、改良与合理利用.在<全国生态环境建设规划>划分的8个生态环境建设类型区的基础上,提出了以流域为单元进行生态环境建设分区配置的必要性.并以黄河流域上中游为例,重点探讨了其生态环境建设分区的方法与成果.作者采用综合的生态经济指标,以县为单元,将西北地区黄河流域划分为6个生态环境建设区,即风沙区、黄土丘陵沟壑区、黄土高塬沟壑区、沿河阶地与平原区、土石山区、河源区.在分区的基础上,确定了各区生态环境建设的生态经济目标及相应的措施配置模式.针对生态环境建设中存在的问题,提出了对策建议以流域为单元进行生态环境建设分区;因地制宜建设主攻方向;积极稳步推进"退耕还林还草";加大投资力度,拓宽投资渠道;加强法制建设,把预防监督放在首位;充分满足生态环境建设的需水要求. 相似文献
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In this study, we trace the history of policy development within the Global Partnership for Education to discern the drivers behind the uptake of its shifting policies relating to education in fragile and conflict-affected states. In order to elucidate how and why this international organization has altered its policy stance and funding modalities, we employ a process tracing analysis of document and interview data. Moreover, we provide three country case studies of Global Partnership for Education financing to Liberia, Madagascar, and the Democratic Republic of the Congo. 相似文献
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黄培清 《乐山师范学院学报》2014,(10):49-52
《故都的秋》是中国现代散文中不可多得的佳作,市场上有多种英译本流传。张培基的译本语言自然贴切,形神兼备,灵活地再现了原文的风情,享有较高的声誉。从生态翻译学的角度解读,译者选择翻译《故都的秋》,是译者对"需要"和"能力"适应/选择的结果;译者之所以能够取得成功,是因为译者能够多维度适应整体翻译生态环境,并很好地实现了语言维、文化维和交际维的适应性选择转换,使译文取得了较高的"整合适应选择度"。 相似文献
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Pushpa Durgawale P. S. Shukla Sonali Mishra 《Indian journal of clinical biochemistry : IJCB》1999,14(2):241-244
An unexpected increase in erythrocyte osmotic resistance during viral hepatitis in two patients prompted study of effects
of hepatitis (in Karad) on osmotic resistance. The test was performed by placing erythrocytes in saline solutions of decreasing
osmolarity and osmotic fragility defined in terms of the saline concentration at which hemolysis begins. Study included 44
infected subjects (acute viral hepatitis non-A non-B). All forty four infected subjects showed abnormal results when compared
to normal subjects. increased erythrocyte osmotic resistance i.e. hemolysis begins between 0.45% to 0.40% of NaCl and is completed
between 0.25% to 0.20% NaCl, whereas in normal subjects. hemolysis begins between 0.50% to 0.45% NaCl and is completed between
0.35% to 0.30% NaCl. Osmotic resistance was observed with increase in total bilirubin (mean±SD) (4.6 ±3.6), direct bilirubin
(3.0±2.5), SGOT (58.8±55.5) SGPT (114.2±150.3) activity. Physiologic shifts in erythrocyte osmotic resistance may be due to
changes in membrane lipid ratio. 相似文献
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葛炳星 《武汉工程职业技术学院学报》2004,16(2):63-67
商业秘密是企业重要的无形资产，也是企业形成和谋求长期竞争优势的重要手段。在市场经济中，信息社会里，对企业商业秘密侵蚀无处不在，防范企业商业秘密被侵蚀是企业永恒的主题。由于商业秘密具有非专有性特征，决定了企业对其商业秘密的保护具有脆弱性，容易产生失密、权利被侵犯等问题。单一的保护方法也难以达到企业对商业秘密的目的。因此必须采取综合手段才能达到有效预防保护的目的。 相似文献
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韩德志 《重庆大学学报(英文版)》2005,4(1):41-46
1 Introduction1 With the rapid development of Internet, digital multimedia can be easily shared via computer networks and conveniently processed for queries in databases. At the same time, the powerful multimedia manipulation software has made it possible to edit and alter the media’s content seamlessly, which breeds the demand of a secure authentication system to verify authentication. Digital watermarking has been proposed as a possible solution for data and tamper detection. An authentica… 相似文献
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Gabriel J. Stylianides Andreas J. Stylianides George N. Philippou 《Journal of Mathematics Teacher Education》2007,10(3):145-166
There is a growing effort to make proof central to all students’ mathematical experiences across all grades. Success in this goal depends highly on teachers’ knowledge
of proof, but limited research has examined this knowledge. This paper contributes to this domain of research by investigating
preservice elementary and secondary school mathematics teachers’ knowledge of proof by mathematical induction. This research
can inform the knowledge about preservice teachers that mathematics teacher educators need in order to effectively teach proof to preservice teachers. Our analysis is based
on written responses of 95 participants to specially developed tasks and on semi-structured interviews with 11 of them. The
findings show that preservice teachers from both groups have difficulties that center around: (1) the essence of the base
step of the induction method; (2) the meaning associated with the inductive step in proving the implication P(k) ⇒ P(k + 1) for an arbitrary k in the domain of discourse of P(n); and (3) the possibility of the truth set of a sentence in a statement proved by mathematical induction to include values
outside its domain of discourse. The difficulties about the base and inductive steps are more salient among preservice elementary
than secondary school teachers, but the difficulties about whether proofs by induction should be as encompassing as they could
be are equally important for both groups. Implications for mathematics teacher education and future research are discussed
in light of these findings.
相似文献
| George N. PhilippouEmail: |
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中国经济增长与环境脆弱性的因果及冲击响应分析 总被引：14，自引：1，他引：14
随着我国经济建设的不断深入，环境问题越来越严重。我们也越来越需要以科学的手段，运用统计推断的方法，从实际观测数据中对经济与环境的关系特别是因果关系做出客观判断。本文采用主成分分析方法对我国环境脆弱性进行了测度，运用格兰杰因果与脉冲响应函数分析中国经济增长与环境脆弱性之间的关系。结果显示：中国经济增长与环境脆弱性之间存在着互为因果的关系，但是经济增长与环境脆弱性之间是否存在格兰杰因果关系在很大程度上受到了其滞后期数的影响，而且这两者对对方的影响还存在着明显的差异。经济增长对环境脆弱性的影响具有明显的时滞性，是一种长期的、渐进的影响；而环境脆弱性对经济增长的影响的时滞却较短，是一种短期的、非渐进的影响。 相似文献