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在双稳态系统的图式形成的研究中,Exteneded Fisher-Kolmogorov(EFK)方程至关重要.文章研究了二维EFK方程解的长时间行为,证明了该方程解算子的存在唯一性和解算子在L2(Ω)及H2(Ω)中存在吸收集,最后证明了该方程在L2(Ω)中存在全局吸引子. 相似文献
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Mark Y. L. Wang 《Asia Pacific viewpoint》1997,38(1):1-18
Since the economic reforms launched at the end of the 1970s, China has experienced dramatic socioeconomic change which has led to the emergence of new and distinctive regions of economic interaction characterised by an extensive and intensive mix of agricultural and non-agricultural activities. This paper illustrates the nature and characteristics of these evolving Extended Metropolitan Regions (EMRs) by drawing on the experience of the Shenyang-Dalian urban corridor in Northeast China (Manchuria). The increased level of economic interaction between the cities and the countryside is characterised by accelerated labour and capital flows, rapidly expanding rural-urban commodity trade and subcontracting between urban and rural enterprises. The result is a rapid erosion of differences in the standard of living, economic function and life style between the city and the countryside. 相似文献
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在c〉1/d条件下,得到了推广的Pickands型估计量↑^pn（c,d）的分布的渐近正态展式． 相似文献
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为了使农村最低生活保障标准的制定能够客观真实反映农村贫困家庭的基本生活需求,在总结福建省最低生活保障制度实施、取得成效以及存在问题的基础上,采用扩展线性支出系统模型,选取代表农村贫困家庭生存权、教育权及健康权(食品消费支出、衣着消费、居住消费、文教娱乐用品及服务、医疗保健等5类)生活消费支出的数据,进行测算福建省农村最低生活保障标准。结果表明,2007-2011年福建省施行的农村最低保障标准与测算标准之间存在着差距,农村低保标准整体偏低。最后,提出结合消费水平度量贫困,建立以公共财政为主体的多元的筹资机制,完善低保资金的省级财政转移支付制度,建立城乡一体化的低保制度,健全综合性的社会救助体系等政策建议。 相似文献
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李彬 《农业图书情报学刊》2012,24(5):177-181
以文献计量学的基本定律作为数据分析的基本方法,对1994-2011年《CNKI期刊全文数据库》中的395篇图书馆延伸服务研究论文的年代分布、期刊分布、获基金支持情况、著者情况、机构分布、主题等进行统计分析,以量化的方式描述我国图书馆延伸服务领域研究的状况和成果。 相似文献
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《Veterinary microbiology》2015,175(1):85-91
Multidrug resistant Salmonella Kentucky strains have been isolated from turkeys in Poland since 2009. Multiple mutations within chromosomal genes gyrA and parC were responsible for high-level ciprofloxacin resistance. One of the isolates was extended spectrum β-lactamase- (ESBL) positive: the strain 1643/2010 carried a conjugative 167,779 bps plasmid of IncA/C family. The sequence analysis revealed that it carried a blaCTX-M-25 gene and an integron with another β-lactamase encoding gene—blaOXA-21. This is the first known report of a CTX-M-25 encoding gene both in Poland and in Salmonella Kentucky world-wide, as well as in the IncA/C plasmid. Analysis of the integron showed a novel arrangement of gene cassettes—aacA4, aacC-A1 and blaOXA-21 where the latter might result from an intergeneric gene transfer. The study confirmed Salmonella Kentucky population isolated in Poland belongs to global epidemics of high level fluoroquinolone resistant clone ST198 that can carry rare β-lactamase genes. 相似文献
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甘蓝显性雄性不育基因的延长随机引物扩增DNA(ERPAD)标记 总被引：10，自引：2，他引：8
获得了一个与甘蓝显性雄性不育基因连锁的延长随机引物扩增ＤＮＡ（ＥｘｔｅｎｄｅｄＲａｎｄｏｍＰｒｉｍｅｒＡｍｐｌｉｆｉｅｄＤＮＡ，ＥＲＰＡＤ）标记ＥＰＴ１１９００。ＥＰＴ１１９００是在与甘蓝显性雄性不育基因连锁的ＲＡＰＤ标记ＯＴ１１９００的基础上，通过逐步筛选３’端延长的随机引物的方法转化而成的稳定性和特异性都得到增强的新标记。这种标记的稳定性和特异性接近ＳＣＡＲ标记，但不需要克隆和测序。该方法首先根据ＯＰＴ１１的序列合成３’端添加Ａ、Ｔ、Ｃ、Ｇ４种碱基的４个引物，组成１０个引物对。以不育池为模板筛选出ＯＴ１１Ｃ＋ＯＴ１１Ｇ为唯一能够扩增长度与ＯＴ１１９００相同的一个片段的引物对。在此引物对基础上，又添加４种碱基得到８个新的引物，相互组合成１６个引物对。进一步以不育池为模板筛选出ＯＴ１１ＣＴ＋ＯＴ１１ＧＡ，在严格条件下，它可特异扩增长度与ＯＴ１１９００相同的一个片段ＥＰＴ１１９００。通过分离群体分析证实这一片段与ＯＴ１１９００处于同一位点。 相似文献