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351.
数字植物区系学产生的背景主要是由于传统植物区系学的方法缺陷不能解决大尺度、大范围植物区系的比较研究以及数字化技术的日趋成熟;它的主要研究内容包括植物区系量化研究的理论基础、方法体系、比较标准及其数字指标等问题,如不同植物区系的丰富性综合评价,不同植物区系成分的划分与内在联系、区系性质异同的确认,不同植物区系相似关系分析、亲缘关系的确定、区系来源和种子植物系统发育的探索,不同植物区系的地理归属,量化研究并验证吴征镒院士所提出的中国种子植物属的各个分布区类型和我国种子植物特有、孑遗以及具有标识性类群(如间断分布类群和在系统演化中的原始类群等)的分布格局、分布规律、分布中心和趋近分布中心程度,以及量化研究并验证吴征镒院士提出的中国植物区系的热带亲缘思想、王文采院士提出的东亚一些植物的间断分布式样和迁移路线与汤彦承教授提出的东亚植物区系第三纪源头等问题. 相似文献
352.
我国绿色饭店建设的现状与对策 总被引:3,自引:0,他引:3
廖丽华 《湖南环境生物职业技术学院学报》2006,12(1):86-89
创建绿色饭店已成为新世纪饭店业发展必然趋势.在我国,饭店的创绿活动已如火如荼的展开.本文从绿色饭店的概念入手,分析建设绿色饭店的意义,总结了我国绿色饭店建设的现状,提出了饭店实施绿色计划所面临的任务和对策. 相似文献
353.
介绍了隆回县金银花资源培育和加工利用现状,综合分析了金银花的综合价值和发展前景,针对当前金银花产业发展中存在的经营方式落后、加工粗放、销售不畅等问题,提出了金银花产业发展的对策. 相似文献
354.
The stream goby Rhinogobius sp. DA (dark color type) shows exclusive paternal care of the eggs. Males court females in the stream current and previous field observations suggest that females favor males that perform their courtship display in faster water currents, and that such males may have high parental ability because of good physical condition. To validate these observations we examined female choice under controlled laboratory conditions. Mate choice experiments indicated clearly that females preferred males that courted in the faster currents, whereas neither sexually different morphological traits, such as body size, nor the water current alone were important. The experiments with food supply treatments indicated that only males of high physical condition are able to court in the fast currents. Furthermore, males that courted in the fast currents achieved good egg survival, whereas males that were unable to court in the currents did not, due to cannibalism of their egg clutch. Thus, the maximum speed of the water current in which a male courts should be indicative of his quality and of the subsequent survival of eggs under his care. We conclude that Rhinogobius sp. DA females utilize the male courtship display in the water current as an honest indicator of parental quality.Communicated by K. LindströmAn erratum to this article can be found at 相似文献
355.
汕头港水域潮流运动的三维数值模拟 总被引:1,自引:1,他引:1
本文建立了汕头港水域的三维潮流数学模型,并采用交错网格(Arakawac)的差分方法求解,实际运用表明,该模型计算程序简单,计算结果合理,精度较好,模拟结果能较好地揭示计算区域内的潮流结构特征。 相似文献
356.
A study on the elemental composition of aerosol, water and soil in the Mt. Namjagbarwa region, Tibet, was carried out in the period of 1982 to 1984. Samples of aerosol particles were collected by cascade impactor and analyzed for 10 elements by PIXE. Samples of ice, snow and water were collected and analyzed for trace metals, major cations and anions. The pH values of water were at quasi-neutrality or neutrality, and the hardness of water was low. Contents and physico-chemical composition of 20 elements in the major types of soil were determined by physico-chemical methods. Levels of elements in soil varied with soil type and their parent materials. Contents of some elements were higher in the substratum soil derived from in situ than in the surface soil. The region was in a remote area with negligible pollution and could be considered as a good location for measuring the baskground value of environmental sample. 相似文献
357.
通过对甘肃省土壤环境机械组成的调查研究,较全面、系统地获得了各种元素、土类以及各区域的土壤环境机械组成,找出了本省土壤环境机械组成特征及其分布规律。 相似文献
358.
Libiseller C Grimvall A Waldén J Saari H 《Environmental monitoring and assessment》2005,100(1-3):33-52
Despite extensive efforts to ensure that sampling and installation and maintenance of instruments are as efficient as possible when monitoring air pollution data, there is still an indisputable need for statistical post processing (quality assessment). We examined data on tropospheric ozone and found that meteorological normalisation can reveal (i) errors that have not been eliminated by established procedures for quality assurance and control of collected data, as well as (ii) inaccuracies that may have a detrimental effect on the results of statistical tests for temporal trends. Moreover, we observed that the quality assessment of collected data could be further strengthened by combining meteorological normalisation with non-parametric smoothing techniques for seasonal adjustment and detection of sudden shifts in level. Closer examination of apparent trends in tropospheric ozone records from EMEP (European Monitoring and Evaluation Programme) sites in Finland showed that, even if potential raw data errors were taken into account, there was strong evidence of upward trends during winter and early spring. 相似文献
359.
我国土壤中钛,锆,铪和钽的环境背景值及分布规律 总被引:1,自引:0,他引:1
在大量土壤样品分析数据的基础上,讨论了钛、锆、铪和钽在不同土类和地区的环境背景值的分布趋势和主要影响因素. 相似文献
360.
The long-term (40 yr) observation results of phosphates–phosphorus concentration and its runoff in the Lithuanian fourth largest river Nevezis are analysed. Amounts and peculiarities of background runoff, agricultural runoff, andpoint source pollution from towns were studied for various periods. It has been determined that phosphates enter into the river Nevezis mainly from towns (76.5%), from agricultureonly up to 16%, and the background runoff for 7.5%.Considerable agricultural influence was observed in 1979–1991,when the phosphate runoff increased to 22 kg P km-2 a-1 and formed in 1984 33% of the entire runoff. A relation of the phosphates runoff from agriculture, for the entire study period, was obtained with the number of animals in the river's basin. Since 1990, when the number of animals started to decrease, the runoff of phosphates decreased too. Now the phosphatesrunoff from agriculture formed only 2% of the entire runoff. Water in the river Nevezis is heavily polluted with phosphate,according to the EU general classification of the water quality of rivers, although the Lithuanian pollution norms for effluentsdischarging to surface water are not exceeded. Norms for effluents discharging in the rivers from point-sources pollution should be made stricter and the highest permitted ratiobetween the phosphorus load in the river and its waterdischarge should be established. 相似文献