粤港澳大湾区外商直接投资对制造业集聚的空间溢出效应

湾区以其丰富的自然资源禀赋和独特的开放优势在带动全球经济发展和技术进步中发挥着重要作用,通过外商直接投资溢出效应实现湾区制造业集聚发展,已经成为引领湾区经济开放化和多元化的重要途径。采用区位熵方法测算了2010—2019年粤港澳大湾区各城市制造业及其细分行业集聚度,并通过SEM和SDM模型分析了外商直接投资对制造业集聚的影响效应。研究发现：1）粤港澳大湾区产业分工明晰,产业集聚特征明显。2）粤港澳大湾区外商直接投资对制造业集聚存在明显的空间外溢效应,在邻接矩阵和经济地理矩阵下影响系数分别为0.213和0.121;市场规模和技术创新对本地制造业集聚的影响系数为0.063和0.316,促进了本地制造业发展;资本存量对周边地区制造业集聚产生积极的促进作用,影响系数为0.918。发挥粤港澳大湾区的产业集群的优势,有利于为广东地区乃至整个泛珠三角产业均衡化发展提供引领作用。     

内蒙古鄂伦春西林梯铅锌钼矿床地质特征及矿床成因

研究区位于大兴安岭晚古生代、中生代CuPbZnAuAg多金属成矿带北段,中—晚华力西期韧性推覆构造贯穿全区。矿区圈定出1条含钼铅锌银矿化蚀变带,27条钼矿体、6条铅锌矿体,斑岩体控制了矿化蚀变带的空间分布、形态及产状。早白垩世花岗斑岩在空间上、成因上与矿化活动关系密切,是成矿最主要的热源、矿源。矿体产出于斑岩体顶部,向深部矿化蚀变均有变厚和增强趋势。铅锌钼矿体脉群底部具有形成厚大斑岩型钼矿体的最佳地质条件。初步认为矿床类型属热液脉型钼多金属矿床。矿区经历多期次构造—岩浆活动,特别是燕山晚期岩浆侵入与火山喷发活动异常强烈,成矿条件优越。     

苏北沿运河旅游轴合作发展策略

沿古运河旅游轴建设已成为推动苏北区域旅游经济创新发展的主导战略。文章总结了区域旅游合作研究理论概要,提出基于区域旅游发展阶段性的区域旅游的四种合作模式,结合沿运河旅游资源的空间组合提出了推进苏北沿运河旅游轴合作发展的六大策略:构建"三位一体"的合作主体;建立制度化的区域合作协调机构;形成以市场为主导、政府推动的合作机制;建设大运河旅游信息平台和游客信息中心;拓宽沿运河旅游轴的合作领域,延伸旅游产业链条;优化运河旅游轴线空间组织,互动轴带内和轴带间。     

Flood Prevention and Watershed Management An Overview

Abstract

Web Sites are becoming mainstream, necessary components of every organization's mandate, whether that organization is governmental, academic or commercially based. With this popularity comes an increasing demand for intelligent web design: simple, attractive, easy-to-navigate style that balances well-written content with useful web technologies and freshness that will keep people coming back. The Great Lakes Information Network (GLIN) has been employing these principles of Web design since its beginnings in 1993, focusing first on supplying useful content and secondly, ensuring that the useful content is well-organized and easy-to-navigate. By forming online partnerships with hundreds of groups involved in management of the Great Lakes ecosystem, GLIN represents a united Web presence for the entire region.     

Historic occurrence of parthenogenetic Artemia in Great Salt Lake,USA, as demonstrated by molecular analysis of field samples

Great Salt Lake (GSL), USA is the main source of the commercially important Artemia franciscana Kellogg (1906) cysts used in larviculture. Our objective was to document the presence of parthenogenetic Artemia in GSL analysing a series of non-commercial samples harvested over the period 1997–2005. Laboratory cultures suggested that sex ratios were skewed in some years. Species-specific restriction fragment length polymorphisms in the exon-7 of the Na/K-ATPase α-1 subunit nuclear gene and of a fragment of exon-2 of the heat shock protein HSP26 gene were used to identify samples of individual adults and pooled cysts. Additionally, denaturing gradient gel electrophoresis using the Na/K-ATPase marker and individual adults was used because of its greater power for detecting different alleles. Finally, the exon of the Na/K-ATPase α-1 subunit was sequenced in selected individuals to validate the results. All results indicated that there were parthenogenetic Artemia in the samples from the period 2000 to 2002. Our data do not provide evidence on the autochthonous or allochthonous nature of this population, although an anthropogenic origin seems most likely. The transitory character of the incidence of parthenogenetic Artemia can be linked to unusual environmental conditions in the lake around the turn of the century. The subsequent disappearance of the parthenogenetic population would then be due to the competition with the more productive A. franciscana population as conditions returned back to normal. A systematic genetic study of the GSL Artemia population is recommended as it may provide valuable complementary information about population changes undetected in traditional monitoring programmes.     

赣州市2003年大旱成因及对策

通过江西省赣州市2003年旱情和灾情的回顾,详细分析了旱灾成因,并提出了今后抗旱减灾的对策与措施．     

Assessing impaired benthic communities using sediment toxicity and contaminant concentrations from reference sites inside the Niagara River Area of Concern

Anthropogenically degraded benthic-macroinvertebrate communities (benthos) are one of seven beneficial use impairments (BUIs) in the Niagara River Area of Concern (AOC). Over the last 50 years, upgrades to waste-water treatment, industry closures, and sediment remediations reduced contaminant levels throughout the system. Improvements in benthic communities and sediment toxicity, however, were difficult to assess because there are no comparable reference reaches outside the AOC. A multi-phase study was initiated in 2015 to determine if data from inside the AOC could identify reference conditions, if toxicity and benthic-community data from these sites differed from other AOC sites, and if further remediation efforts were warranted in parts of the AOC. Concentrations or quotients of PAHs, PCBs, dioxins and furans, pesticides, and most metals were below their New York Sediment Class A Guidance Values at 10 sites that were subsequently designated as reference sites. Survival and growth data from Chironomus dilutus and Hyalella azteca bioassays indicated that sediments from only a few individual AOC-impact sites were toxic or significantly different from reference sites, and that mean toxicity at pooled AOC-impact and reference sites did not differ significantly. Similarly, New York Biological Assessment Profile scores and chironomid mentum deformity scores at only a few individual sites differed significantly from corresponding indices at reference sites, but neither metric differed significantly in comparisons between pooled AOC-impact and reference sites. Most analyses indicated that benthic communities were unimpaired and that removal criteria for the benthos BUI were largely met in much of the upper Niagara River AOC.