改进的大气环境后量评价方法及应用

运用模糊集理论中的权距离和隶属度概念推导出一种改进的大气环境质量评价方法,评价过程能充分利用实际数据所包含的各种信息.实例应用结果表明,与广泛采用的模糊综合评判模型相比较,本文提出的评价方法得到的评价结果更为合理可靠.     

城市交通规划环境影响评价的方法与实践

在分析现有交通规划、机动车尾气排放、交通噪声理论模型的基础上,提出了一套城市交通规划环境影响评价的实用方法,并结合北京市昌平卫星城东区的综合交通规划给出了该方法的应用案例.     

我国植被恢复中的几个误区及应用生态学原理的植被恢复方法探究

介绍了我国植被恢复中存在的问题,由此引出天然植被的重要价值:保持水土和营养;防止水灾、旱灾、火灾、暴风雨、虫害;防止污染;防止水土流失和沙漠化;调节地区与全球气候;保护生物多样性以及可再生能源等.在此基础上分析了我国植被恢复的误区:大量使用外来物种;忽略了健康生态系统要求的异质性;忽略了物种之间的相互作用;忽略了农业区的植被恢复;覆盖率常被用作唯一的评估标准;对当地濒危物种的需要缺乏考虑;城市绿化忽略了植被的生态功能.针对这些误区提出了笔者认为符合生态学原理的植被恢复措施.     

长江口底沙再悬浮对重金属迁移的影响

通过分析长江口南槽上段白龙港排污口邻近水域14 h不间断定点剖面上采集的水体中颗粒态和溶解态重金属元素Zn,Cu,As,Cd,V,Cr,Ni和Pb浓度,研究潮周期内表层沉积物的再悬浮对重金属在颗粒态和溶解态中分配和迁移的影响.结果表明:潮周期内中层单位质量悬沙的重金属浓度(Mp)始终大于底层;随着含沙量(TSS)增大,单位悬沙的各重金属浓度(Mp)减小,水体中各重金属颗粒态浓度(Ms)增大,溶解态浓度(Md)减小;当含沙量大于一定值时,单位悬沙的各重金属浓度趋向稳定值;含沙量分别在涨憩和落急时达到峰值,所以涨憩沙峰时刻有利于重金属的吸附,但落急沙峰时刻因流速较大,不利于重金属的吸附.因此,转流时水质较涨、落急好.     

模糊识别方法在港口大气环境质量评价中的应用

在模糊集理沦中的权距离和隶属度概念基础上，将模糊识别方法应用于对港口大气环境质量的综合评价，评价过程能充分利用实际数据所包含的各种信息。实例应用结果表明，与上海大气指数法相比较，文中提出的评价方法得到的评价结果更为合理可靠。     

Analysis on the long term discharge of a catchment

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长光路FTIR研究HFC152a光化学反应

用长光路ＦＴＩＲ技术研究氟里昂替代物ＨＦＣ１５２ａ（ＣＨ３ＣＨＦ２）在对流层中的化学反应，氯离子作反应的引发剂，用相对速度方法测定了ＨＦＣ１５２ａ与Ｃｌ原子反应速率常数为（２．３±０．５）×１０＾－１３ｃｍ＾３·ｍｏｌ＾－１·ｓ＾－１（２９８±Ｋ）。ＨＦＣ１５２ａ在对流层中的主要含氟光解产物为ＣＯＦ２，产率为８８％。有关反应机理进行了讨论。     

中国1961-2000年月平均气温空间插值方法与空间分布

利用地理信息系统软件ARC/INFO,在考虑海拔高度对气温影响和没有考虑海拔高度对气温影响的两种情况下,分别运用样条插值法、普通克立格法和逆距离权重法对中国623个气象站1961—2000年40 a的逐月平均气温进行了空间插值,并利用交叉检验方法对插值精度进行了评估,结果表明:考虑了海拔高度影响的3种插值方法的精度都有比较明显的提高,对于普通克立格法,平均绝对误差(MAE)从1.44℃降到0.82℃,均方根误差(RMSE)从2.31℃降到1.28℃;对于逆距离权重法,MAE从1.52℃降到0.88℃,RMSE从2.38℃降到1.34℃;对于样条插值法,MAE从1.54℃降到0.87℃,RMSE从2.49℃降到1.35℃。在6种插值方法中,考虑了海拔高度影响的普通克立格法是最优空间插值方法。     

Impacts of flight distance on sex ratio and resource allocation to offspring in the leafcutter bee, Megachile rotundata

Fisher's theoretical prediction of equal investment in each sex for a panmictic population (The genetical theory of natural selection. Clarendon, Oxford, 1930) can be altered by a number of factors. For example, the sex ratio theory predicts variation in equal investment in each sex when the maternal fitness gains from increased investment differ between sexes. Changing sex allocation because of changing payoffs may result from different ecological situations, such as foraging conditions. We investigated the impact of foraging travel cost on relative investment in sons vs daughters. Field studies were carried out with the central-place-foraging leafcutter bee Megachile rotundata (Fabricius), which has smaller males than females. Therefore, less investment is required to produce a viable son compared with a daughter. We found that with increased flight distance to resources, females produced a greater proportion of sons. Females also invested fewer resources in individual sons and daughters and produced fewer offspring with increased flight distance.     

To fission or to fusion: effects of community size on wild chimpanzee (<Emphasis Type="Italic">Pan troglodytes verus</Emphasis>) social organisation

To balance advantages and disadvantages of group living, some species have fission-fusion social systems in which members of the same group form frequently changing subgroups. This allows flexible responses of group size to external conditions while at the same time retaining group stability. In chimpanzees, subgroup (party) size and composition depend mainly on the presence of receptive females, food availability and the activity of the party. Here we analyse the extent to which fission-fusion parameters are influenced by changes of demographic variables like community size and composition. Data were collected from a habituated West African chimpanzee community (Taï forest, Côte dIvoire) over 10 years, during which total community size decreased from 51 to 21, and the number of adult males decreased from 9 to 2. Taï chimpanzees are highly gregarious, as they spend more than 80% of their time with unrelated conspecifics. With decreasing community size, party size, party duration and male-female association increased. Neither activity nor the presence of receptive females or feeding competition could explain the observed changes in grouping patterns. Thus, the decrease in community size led to an increase of party cohesion and also enhanced cohesiveness between the sexes, while general sociality remained unchanged. Therefore, our data support the notion that small communities are more cohesive and have a less flexible fission-fusion system.Communicated by D. Watts