取代氮杂环类有机物水溶解度的估算与测定

本文采用一种修正的分子连接性指数研究了氮杂环类化合物水溶解度的定量结构性性质关系，这种修正的分子连接性指数是由原子半么取代原子的点价计算得来。逐步多元统计回归表明氮杂环的水溶解度和２阶及５阶原子半么分子连接性指数呈良好的相关性。     

生态城市的指标体系与评价方法

本文从城市生态系统结构，功能和功调度三方面构建了生态城市的指标体系，提出了生态城市的评价方法，并选择上海，深圳，天津，香港等五个沿海城市进行了城市生态化程度的分析。     

附着生物对沉水植物伊乐藻生长的研究

以沉水植物伊乐藻(Elodea nuttalii(Plant.)ST.John.)为研究对象,室内利用原位湖水进行培养,通过测定伊乐藻的生物量、叶绿素质量分数、光合作用速率等指标,研究了附着生物量的增加对沉水植物伊乐藻的影响。结果表明,随着附着生物处理量的增加,伊乐藻的生物量、叶绿素质量分数以及光合作用速率随之下降,50d后,各处理的生物量与对照相比分别减少了约5%~15%,叶绿素质量分数以及光合作用速率下降了20%~43%、10%~36%。同时也分析了丝状藻对沉水植物伊乐藻的遮阴作用,初步推测附着生物对沉水植物伊乐藻的影响可能是由于附着生物的遮荫作用。研究的结果为揭示富营养化湖泊沉水植被衰退的机理提供了理论依据。     

SPATIAL COMPARABILITY OF THE PALMER DROUGHT SEVERITY INDEX1

ABSTRACT: The Palmer Drought Severity Index, which is intended to be of reasonable comparable local significance both in space and time, has been extensively used as a measure of drought for both agricultural and water resource management. This study examines the spatial comparability of Palmer's (1965) definition of severe and extreme drought. Index values have been computed for 1035 sites with at least 60 years of record that are scattered across the contiguous United States, and quantile values corresponding to a specified index value were calculated for given months and then mapped. The analyses show that severe or extreme droughts, as defined by Palmer (1965), are not spatially comparable in terms of identifying rare events. The wide variation across the country in the frequency of occurrence of Palmer's (1965) extreme droughts reflects the differences in the variability of precipitation, as well as the average amount of precipitation. It is recommended first, that a drought index be developed which considers both variability and averages; and second, that water resource managers and planners define a drought in terms of an index value that corresponds to the expected quantile (return period) of the event.     

Effects of channel incision on base flow stream habitats and fishes

Channel incision is a widespread phenomenon that results in stream and riparian habitat degradation. Fishes and physical habitat variables were sampled at base flow from three incised stream channels and one reference stream in northwest Mississippi, USA, to quantify incision effects on fish habitat and provide a basis for habitat rehabilitation planning and design. Incised channels were sampled in spring and autumn; the reference channel was sampled only in the autumn. Incised channel habitat quality was inferior to the reference channel despite the presence of structures designed to restore channel stability. Incised channels had physical habitat diversity levels similar to a nonincised reference channel, but contained fewer types of habitat. At base flow, incised channels were dominated by shallow, sandy habitats, moderate to high mean local Froude numbers, and had relatively little organic debris in their beds. In contrast, the reference stream had greater mean water depth, contained more woody debris, and provided more deep pool habitat. Fish assemblages in incised channels were composed of smaller fishes representing fewer species relative to the reference site. Fish species richness was directly proportional to the mean local Froude number, an indicator of the availability of pool habitat.     

TOWARDS CHARACTERIZING AND PLANNING FOR DROUGHT IN VERMONT‐PART I: A CLIMATOLOGICAL PERSPECTWE1

ABSTRACT: In the Green Mountain state of Vermont, droughts of one form or another and of varying intensities, seventies, and areal extent are not uncommon occurrences. The 1990s were marked by at least three drought events of which the 1998 to 1999 was the most recent. In spite of this recurrence, ongoing drought monitoring and mitigative planning efforts are not as advanced as they could be and no official drought plan exists for the state. This article is the first of two in this volume. It summarizes the cascade of drought types that impacted the state during the 1998 to 1999 episode. From a number of precipitation statistics and drought indices, fine spatial scales (county or better) were found to best capture the character of drought impacts, while the weekly time step is recommended as the temporal unit around which to base planning and monitoring efforts. The companion article outlines a possible framework for drought planning efforts and highlights key constituencies to be included in the process.     

Ecological network analysis for water use systems—A case study of the Yellow River Basin

Ecological network analysis (ENA) is introduced in this paper as a promising approach to study water use systems. Information indices from ENA involving total system throughput (TST), ascendency and overhead are calculated here. Two related aspects including organization inherent in system structures and synthesized water use intensity related with sustainable development of water use systems are analyzed. The indices of ascendency and overhead are applied for analyzing and characterizing water use network organization. For comparison of sustainability of water use systems from integrated aspects of environment, society and economy and based on TST, a new indicator termed as total system throughput intensity (TSTI) is constructed incorporating parameters of land, precipitation, population, GDP and environmental flow, which can be used as a measure of sustainability in terms of synthesized water use intensity. The Yellow River Basin in China during 1998–2006 is chosen as the case study and divided into subsystems according to the six river sections as from source to Lanzhou (S1-L1), Lanzhou to Toudaoguai (L1-T), Toudaoguai to Longmen (T-L2), Longmen to Sanmenxia (L2-S2), Sanmenxia to Huayuankou (S2-H) and Huayuankou to the mouth of Bo Sea (H-B). The results show that (i) the organization levels of L1-T and H-B are better than those of S1-L1 and T-L2, with those of L2-S2 and S2-H the worst; (ii) the synthesized water use intensity has been improving, of which T-L2, L2-S2 and S2-H are at the highest levels while H-B the lowest. In addition, the comparison between TSTI and other metrics and the relationship between ascendency and TSTI are discussed, from which the importance of TSTI is reflected and the optimization criterions for sustainable development of six subsystems are derived. It can be concluded that the application of ENA in water use systems can provide new angles for water resource management to address the challenges of assessing and optimizing options to obtain more sustainable water use.     

干旱区绿洲土壤盐渍化程度遥感定量评价

土壤盐渍化是制约渭干河-库车河三角洲绿洲内部植被生长最主要的生态环境地质问题,也是影响区域农业生产的第一障碍性问题.利用Landsat TM遥感数据,构建了多维向量空间下的11个遥感定量指标.首先,采用因子分析方法分析不同程度的盐渍化与这11个指标之间的相关性,并建立因子得分模型.其次,采用Fisher逐步判别分析法从这些指标中筛选出8个与盐渍化程度密切相关的指标:氧化铁、归一化盐分指数、地表反照率、植被指数、TM1、TM5、地表温度、湿度指标,并对这些指标建立判别方程,然后对渭干河—库车河三角洲绿洲典型样区盐渍化程度进行评价,将所有的实地样本分别代入判别方程,通过分析,发现判别方程的精度较高,与实际情况较吻合.轻度盐渍化的判别精度为80.3%,中度盐渍化的判别精度为68.75%,重度盐渍化的判别精度为83.65%.中度盐渍化土地的判别精度与轻度盐渍化、重度盐渍化土地的判别精度相比较低,这与中度盐渍化的光谱特征与其它地物易混淆有关.总之,所选取的指标简单,易于获取,有利于盐渍化的定量分析与评价.     

Hepatotoxic and haematological effects of Nigerian Bonny light crude oil in male albino rats

The effect of Bonny light crude oil was assessed in adult albino rats. The rats were administered with 200, 400, and 800?mg/kg of the crude oil orally for 7 days. Fluid intake was measured daily, and the initial and final animal body weight recorded. Oral crude oil at these doses produced no effect on feed and fluid intake between the test groups and the control group. There was a significant decrease in body weight compared to the control group after 7 days of treatment with the different doses of crude oil.

The toxic effects of the liver and hematological effects were assessed. The packed cell volume (PCV) and total white blood cell (WBC) of the 200?mg/kg group were significantly decreased compared to the respective control values. Administration of 200, 400, and 800 mg/kg of Bonny light crude oil, caused a significant dose-dependent increase in glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT) levels, but a significant decrease in the alkaline phosphatase (AP) level compared to the control. Histological examination indicates that crude oil induced severe pathologic changes in the forms of necrosis and oedema.     

水文变异条件下的黄河干流生态径流特征及生态效应

黄河流域地表水文过程受气候变化与如水库拦蓄等人类活动的严重影响,发生显著变化,多次出现断流现象。深入理解水文变异条件下的径流特征及生态效应,对于黄河流域水资源管理及水资源可持续开发利用具有重要意义。基于此,论文利用多水文指标研究水文变异过程,结合基于流量历时曲线（FDC）的生态剩余和生态赤字等生态径流指标以及水文变异总体评价指标D_o和DHRAM（Dundee Hydrological Regime Alteration Method）来描述黄河干流大中型水利工程对下游河道水文情势的改变程度,并根据多样性指标SI和IHA（Indicators of Hydrologic Alteration）的拟合关系,进一步分析水文变异的生态效应。研究表明：1）水文情势变异后,FDC整体下移,低于25% FDC流量部分大幅增加,产生生态赤字;2）从上游到下游,降水对各站生态径流指标的影响逐步减小,水库对生态径流指标的影响愈益增大;3）各生态径流指标与大部分IHA指标具有较好的相关关系,能够体现IHA参数的主要信息,可作为衡量黄河流域年和季节径流变化的生态径流指标;4）综合D_o和DHRAM的评价结果,径流过程变异对各站生态风险的影响为：花园口、孙口和利津站为高风险,头道拐和兰州为中等风险,唐乃亥和龙门为低风险;各水文站SI值在20世纪80年代之后均出现下降趋势,其中花园口、孙口和利津3个站的下降幅度较大,生物多样性锐减。