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排序方式: 共有400条查询结果,搜索用时 31 毫秒
41.
北京雾灵山自然保护区冬季鸟类物种多样性调查   总被引:10,自引:2,他引:8  
采用固定调查样线法连续两年对北京雾灵山自然保护区冬季鸟类组成进行了调查,共记录鸟类7目14科44种,其中29种属于留鸟,5种为冬候鸟,7种旅鸟,3种夏候鸟;优势种以留鸟为主,表现出冬季鸟类群落的特点。古北界和东洋界的种类分别为75%和14%,在分布型上划分为7种类型。出现种类最多的生态环境是村落,鸟类种数为31种,其植被类型是低山砾石、农田林果带。调查种类中有国家一级保护鸟类1种,二级保护鸟类6种,北京市重点保护鸟类6种。通过与邻近地区相关调查比较,表明本区冬季鸟类具有较高的丰富性,并提出了有效保护鸟类多样性的对策。  相似文献   
42.
The Kaliningrad region is the westernmost part of the Russian Federation; it includes an enclave on the Baltic Sea inside the European Union separated from mainland Russia by Lithuania and Poland. The incidence of tuberculosis in Kaliningrad has shown a steady and dramatic increase from 83/100 000 in 2000 to 134/100 000 in 2006; the rate of multidrug-resistant tuberculosis (MDR-tuberculosis) in the Kaliningrad region was reported to be 30.5% among newly diagnosed tuberculosis patients. This study presents a first molecular snapshot of the population diversity of Mycobacterium tuberculosis in this region. A total of 90 drug-resistant and susceptible M. tuberculosis strains from Kaliningrad were subjected to spoligotyping, 12-locus MIRU typing and mutation analysis of the drug resistance genes rpoB and katG . A comparison with international databases showed that the M. tuberculosis population in this region shares a joint pool of strains with the European part of Russia, and also exhibits a certain affinity with those of its northern European neighbours, such as Poland and Germany. Comparison of the genotyping and drug resistance data emphasized that the high prevalence of the MDR Beijing genotype strains is a major cause of the adverse epidemiological situation of MDR-tuberculosis in the Kaliningrad region.  相似文献   
43.
北京野生水鸟迁徙规律及其监测策略初探   总被引:1,自引:0,他引:1  
2005年全球暴发的禽流感疫情备受世界关注,候鸟带毒且野生水鸟是禽流感病毒的天然储库已被世界公认,我国野生动物疫源疫病监测工作已被提到重要议事日程.通过对2006~2008年监测数据的分析,发现北京市野生水鸟春季迁徙从2月下旬开始,4月初达到迁徙高峰;9月下旬开始秋季南迁,11月下旬达到迁徙高峰.并分别对北京地区雁鸭类、鹬鸻类、鹭类的迁徙规律进行了分析;根据北京的气候特点分析了野生水鸟的分布和迁徙特点;根据禽流感病毒与温度的关系,提出了北京的重点监测时期及物种.  相似文献   
44.
记述纹石蛾科弓石蛾亚科1新纪录属,美赛弓石蛾属Maesaipsyche,及1新种,即细齿美赛弓石蛾Maesaipsyche serrulata Sun et Yang ,sp.nov.(广西),其阳具缺阳基侧突而与Maesaipsyche mekongensis Mey相似,但新种中附肢背缘近端部具齿突、外侧缘具细齿.并记述绒弓石蛾属Parapsyche 1新种,即北京绒弓石蛾Parapsyche beijingensis Sun et Morse,sp.nov.(北京),该种肛上附肢与第10节完全愈合,阳具特别发达,与Parapsyche kchina Schmid相似;但新种阳茎基背突为1对瘤状突,其上着生短刺,阳茎基背突上方具1兜状结构,背面观时端部膨大成圆盘.新种模式标本保存于南京农业大学昆虫标本馆.  相似文献   
45.
Quan C  Su F  Wang H  Li H 《Steroids》2011,76(14):1527-1534

Background

The need for certified reference materials (CRM) of anabolic-androgenic steroids reference materials was emphasized by the Beijing 2008 Olympic game as a tool to improve comparability, ensuring accuracy and traceability of analytical results for competing athletes. The China National Institute of Metrology (NIM) responded to the state request by providing seven anabolic-androgenic steroids (AAS) reference materials for Beijing Olympic anti-doping, GBW (E) 100086-GBW (E) 100092.

Experimental

This work describes the production of the series of AAS CRMs, according to ISO Guides 34 and 35 [1] and [2], which comprises the material processing, homogeneity and stability assessment, CRMs’ characterization including moisture content, trace metal content. The AASs’ purity values were assigned with collaborative study involved eight laboratories applying high resolution liquid chromatography-diode array detector (HPLC-DAD). Homogeneity of the AAS CRMs were determined by an in-house validated liquid chromatographic methodology. Potential degradation during storage was also investigated and a shelf-life based on this value was established.

Results

The certified values of CRMs were 99.76 ± 0.079%, 99.76 ± 0.25%, 99.63 ± 0.09%, 99.67 ± 0.11%, 98.82 ± 0.56%, 96.30 ± 0.39% and 99.71 ± 0.49% (purity ± expanded uncertainty with confidence level of 95%) for methyltestosterone, testosterone propionate, nandrolone, nandrolone 17-propionate, boldenone, trenbolone acetate and testosterone respectively.

Conclusions

The certified values for all the studied AAS reference materials are traceable to the international system of units (SI). The CRMs developed were applied by 32 laboratory including sports organizations and analytical laboratories during the 2008 Olympic game for anti-doping control.  相似文献   
46.
目的:通过分析北京市方庄地区儿童全血微量营养素的含量及影响因素,研究探讨微量营养素缺乏的防治措施。方法:2011年1月至12月北京中医药大学东方医院儿科门诊1887例健康体检儿童,收集末梢血,采用原子吸收光谱仪检测全血5种微量营养素铜、锌、钙、镁、铁的含量,并从性别、年龄、季节(月份)方面进行比较分析。结果:全血5种微量营养素含量无性别差异(P0.05),但存在季节差异,4-6月铜、锌含量降低;7-9月钙、镁含量降低;10-12月铁含量降低(P0.05)。全血锌、铁含量存在年龄差异,婴幼儿最低(P0.05)。1887例儿童中,缺乏较多的元素依次为铁(38.8%)、钙(22.3%)、锌(12.8%),其中,4-7岁(17.0%)、7-12岁(21.5%)年龄段组以锌缺乏居多。1岁以内(51.2%)、1-3岁(44.6%)年龄段组以铁缺乏居多。全血铜、锌、钙、铁缺乏无性别差异(P0.05)。全血5种微量营养素缺乏存在季节差异,1-3月镁缺乏明显,4-6月铜、锌缺乏明显,10-12月钙、铁缺乏明显(P0.05)。结论:北京市方庄地区儿童主要存在锌、钙、铁的缺乏,以秋冬季及初春明显。其中婴幼儿以铁缺乏为主,学龄前期及学龄期儿童以锌缺乏为主。应加强对此地区儿童的营养宣教和饮食指导。  相似文献   
47.

Background

The ST239 lineage is a globally disseminated, multiply drug-resistant hospital-associated methicillin-resistant Staphylococcus aureus (HA-MRSA). We performed whole-genome sequencing of representative HA-MRSA isolates of the ST239 lineage from bacteremic patients in hospitals in Hong Kong (HK) and Beijing (BJ) and compared them with three published complete genomes of ST239, namely T0131, TW20 and JKD6008. Orthologous gene group (OGG) analyses of the Hong Kong and Beijing cluster strains were also undertaken.

Results

Homology analysis, based on highest-percentage nucleotide identity, indicated that HK isolates were closely related to TW20, whereas BJ isolates were more closely related to T0131 from Tianjin. Phylogenetic analysis, incorporating a total of 30 isolates from different continents, revealed that strains from HK clustered with TW20 into the ‘Asian clade’, whereas BJ isolates and T0131 clustered closely with strains of the ‘Turkish clade’ from Eastern Europe. HK isolates contained the typical φSPβ-like prophage with the SasX gene similar to TW20. In contrast, BJ isolates contained a unique 15 kb PT1028-like prophage but lacked φSPβ-like and φSA1 prophages. Besides distinct mobile genetic elements (MGE) in the two clusters, OGG analyses and whole-genome alignment of these clusters highlighted differences in genes located in the core genome, including the identification of single nucleotide deletions in several genes, resulting in frameshift mutations and the subsequent predicted truncation of encoded proteins involved in metabolism and antimicrobial resistance.

Conclusions

Comparative genomics, based on de novo assembly and deep sequencing of HK and BJ strains, revealed different origins of the ST239 lineage in northern and southern China and identified differences between the two clades at single nucleotide polymorphism (SNP), core gene and MGE levels. The results suggest that ST239 strains isolated in Hong Kong since the 1990s belong to the Asian clade, present mainly in southern Asia, whereas those that emerged in northern China were of a distinct origin, reflecting the complexity of dissemination and the dynamic evolution of this ST239 lineage.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-529) contains supplementary material, which is available to authorized users.  相似文献   
48.
树木花期预报在林果、养蜂、园林和旅游业等方面有很大的实用价值。该文以大山樱(Prunus sargentii)为例,探讨通过花芽形态测量进行花期预报的新方法。通过1998~2000年对北京玉渊潭公园大山樱进行的数据采集和处理,建立了线性和指数两种预报模型。2002年的试报检验表明,采用3株的观测数据,并利用3日滑动平均的方法,对观测数据进行处理后所作的预报,误差在3 d以内的预报达80%以上;2003年连续测报的平均误差,模型1为1.6 d,模型2为2.1 d。这一树木花期预报的物候学新方法,简便易行、建模周期短、预报精度高,在春季芽膨大后,直至露瓣期之前,可以逐日连续发布预报。  相似文献   
49.
王府井东方广场遗址骨制品研究   总被引:5,自引:1,他引:4  
王府井东方广场遗址不仅出土了丰富的石制品,而且也含有较为丰富的骨制品。骨制品可分为骨核、人工骨块、骨片、骨屑和骨器五大类;骨片约占骨制品总数一半;骨器包括刮削器、尖头器、雕刻器和骨铲四类。观察发现:79件骨制品和骨骼可以拼合成33组,45件上有古人类砍砸、切割或刻划的痕迹。丰富的骨制品进一步反映了王府井古人类文化的进步性;同华北地区类似制品比较,它们之间存在着密切的渊源关系。遗物分布特征表明,东方广场遗址是一处古人类的临时居住地。出土的石器、骨器遗物以及大量的动物骨骼化石表明,王府井古人类不仅能够制作石器与骨器用来宰杀与支解猎物,而且具有用火、控火进行烹饪的能力。  相似文献   
50.
The population variation and structure of 115 plants representing 8 populations of Quercus senescens Hand. Mazz. were investigated by amplification fragment length polymorphism (AFLP) analysis.Using TFPGA software,94 polymorphic phenotypic patterns (752%) was obtained using 2 AFLP primer combinations and it was found that genetic variation of different population was negatively correlated with altitudes.Analysis of the genetic structure of populations carried out using analysis of molecular variation (by Arliquin 2000 software),It showed that there was a high significant population differentiation (φst=02956).And neighbour joining dendragram also be constructed based on 2 primer combinations by PAUP software.  相似文献   
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