Subjects: Geosciences >> Geography submitted time 2021-10-10 Cooperative journals: 《干旱区地理》
Abstract： 运用 ArcGIS 空间分析，揭示了 1990—2018 年西北诸河流域土地利用动态变化特征，采用 “压力-状态-响应”（Pressure-state-response，P-S-R）模型和熵权法对指标进行赋权，并分析了西北诸 河流域土地生态安全状况。结果表明：（1）西北诸河流域2015—2018 年综合土地利用动态度为 2.65%，土地利用变化剧烈。2000 年后城乡建设用地年平均单一动态度为4.16%，增长速度最快。 草地主要向沙地、耕地和其他未利用土地转出，流域荒漠区沙地和其他未利用土地之间转换稳 定。（2）西北诸河流域土地生态安全评价指标体系中状态层权重最高，为 0.4985，由指标权重排序 可知，经济社会发展、湿地面积和人口增长是影响西北诸河流域土地生态安全评价的重要因素。（3）1990—2018 年西北诸河流域土地生态安全指数呈递增趋势，1990—2014 年基本处于不安全 级，2015 年后转变为较不安全级，西北诸河流域土地生态安全状况有所好转。本研究为西北诸河 流域土地利用管理规划提供科学依据，为自然流域尺度的土地利用变化及土地生态安全性研究提 供实例。
Subjects: Biology >> Ecology submitted time 2017-06-29 Cooperative journals: 《生态学报》
Abstract：分别以18SrDNA的V4区和V9区为目标基因，采用高通量测序平台和生物信息学方法，分析海水样品中微型和微微型浮游植物多样性。利用在线分析软件对V4（F/R）、V9（F/R）和C4（F/R）3对引物的敏感性、特异性进行了评估和比较，发现自行设计的引物V4（F/R）对真核藻类的扩增特异性高于V9（F/R）和C4（F/R）。高通量测序结果显示，检测样品平均获得68834条原始序列，高质量数据占99%以上，获得基因注释的序列数达94%以上。3对引物V4（F/R）、V9（F/R）、C4（F/R）鉴定的平均微型/微微型浮游植物OTUs数分别为78、42、58，引物V4（F/R）鉴定效率相对较高，同时对细小微胞藻（Micromonas pusilla）、（金牛微球藻Ostreococcus tauri）、密球藻（Pycnococcus provasolii）、抑食金球藻（Aureococcus anophagefferens）、赤潮异弯藻（Heterosigma akashiwo）等优势种检出频率高于引物V9（F/R）。相对已发表的2对引物，设计的引物V4（F/R）对海洋微型和微微型藻类多样性检测更为高效。
Subjects: Other Disciplines >> Synthetic discipline submitted time 2023-03-31 Cooperative journals: 《农业图书情报学报》
Abstract： [Purpose/Significance] Research on the demand and supply analysis of agricultural literature resources is of great significance to the collection construction of agricultural libraries, especially under the current new situation. The demand analysis of academic resources of agricultural science has always been a difficult task for agricultural special libraries because it covers a wide range of disciplines and involves the multiple cross and integrated applications of various disciplines with agriculture science. This paper innovates the methods of demand and supply analysis based on multi-level information organization and fine-grained data analysis, which would discover both the systematic demands and accurate demands of agricultural researchers, and help to adapt to the changes of agricultural science research paradigm. [Method/Process] This study took the Chinese Academy of Agricultural Sciences (CAAS) as an example, collecting its published foreign language journals and the corresponding cited references, as well as its usage data of foreign language electronic journals databases. Then this paper used the methods of citation analysis, subject organization, etc. to analyze the institutional demand characteristics that include literature language, document type, publication years, disciplines distribution, covered subjects and the utilized database of foreign-language periodical resources. The full-text supply rate of foreign-language electronic journals has been calculated to evaluate the satisfaction and the ability of supplying collection resources. The literature comprehensive utilization index has also been calculated to reflect the literature utilization capacity of CAAS's affiliated institutes by the methods of correlation analysis and multiple correlation coefficient weighting. [Results/Conclusions] The results show that the demands of foreign-language journals of CAAS involve not only classical agricultural disciplines but also some emerging and interdisciplinary fields, and there are big gaps in the level of literature supply and utilization among its affiliated institutes. The construction of literature resource supply system of CAAS should strengthen the demand analysis, enrich the subscription mode of full-text resources, and expand the non-full-text resources. As for the agricultural special libraries, the demand and supply analysis of agricultural science literature resources should follow the development trends of agricultural disciplines, taking into account the systematic and prospective demands, and carry out accurate, thematic and knowledge-based demand analysis in the relevant subject areas. Users can also be encouraged to participate in library collection construction, and diversified demand feedback channels should be provided for them. At the same time, resource construction quality and service efficiency evaluation should also be brought to the forefront.
Subjects: Biology >> Ecology Subjects: Geosciences >> Marine Sciences submitted time 2017-03-08 Cooperative journals: 《生态学报》
Abstract：Stoeckeria algicida为甲藻纲胸甲球藻科，有侵噬鱼类细胞杀鱼的能力，可导致鱼类成群死亡，同时也会杀死其他海洋微藻。由于该藻个体微小、形态学鉴定困难，研究较为迟缓，我国海域几乎没有该藻的研究报道。近几年，高通量测序技术的发展极大地推动了微型/微微型浮游植物的鉴定研究，为了解我国辽东湾海域是否存在Stoeckeria algicida及其分布情况，以18S rDNA V4区作为目标基因，结合高通量测序技术，专门设计了微型/微微型浮游植物鉴定引物对V4（F/R），随后对辽东湾2014年四季海水中微型和微微型浮游植物多样性进行了检测。结果发现，Stoeckeria algicida除了春季未检出外，其他季节均有检出，温度是影响该藻繁殖的主要因素。虽然Stoeckeria algicida在整个环境样品中优势度不太明显，但其夏季密度较高（最高达2.753×103个/L），高值区主要分布在辽东湾东西两岸，致灾风险较高，应引起有关方面足够重视。Stoeckeria algicida在我国海域首次报道，其危害后果严峻，必须加强监测监管。
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