Ca~(2+)、Al~(3+)对聚丙烯酰胺在高岭土絮凝过程中作用的影响

在实验条件下,Ca~(2+)、Al~(3+)离子对高岭土的絮凝过程有不利影响,且pH越高Ca~(2+)的影响越大,pH越低,Al~(3+)的影响越大.运用分子轨道(MO)理论、溶液化学计算、电子探针测试等手段,研究探讨了其作用机理.认为在酸性和中性范围内,Ca~(2+)、Al~(3+)离子及它们的羟基络合正离子与聚丙烯酰胺之间的相互作用造成后者分子链发生卷曲,导致絮凝效果下降;而在pH>9范围内,Ca~(2+)、Al~(3+)的氢氧化物沉积在高岭土表面,阻碍或抑制了聚丙烯酰胺与高岭土之间的氢键作用.     

土地覆盖变化与普氏原羚和麋鹿的保护

以普氏原羚Ｐｒｏｃａｐｒａｐｒｚｅｗａｌｓｋｉ和麋鹿Ｅｌａｐｈｕｒｕｓｄａｖｉｄｉａｎｕｓ为例,探讨了土地覆盖变化对中国野生动物的影响和如何在土地覆盖变化的大背景下保存濒危物种。普氏原羚和麋鹿是我国的特有动物。由于近代人口增长、土地利用和土地覆盖变化,普氏原羚分布面积由大变小,濒临绝灭;而随着农田开垦、栖息地丧失,麋鹿最终在野外绝灭。普氏原羚和麋鹿是我国野生动物具有代表性的两个典型例子。土地覆盖变化是我国野生动物濒危的重要原因。在土地覆盖变化的大背景下保存濒危物种的途径有两条：①在野生动物的重要栖息地和繁殖地点建立自然保护区;②对那些已经在野外绝灭,濒临绝灭的野生动物,采取人工圈养,使这些野生动物数量增长,逐步将人工繁育个体重新回归自然。我们正在为普氏原羚建立一个自然保护区,并对麋鹿实施易地保护。从现状分析,麋鹿的重新引入和易地保护是卓有成效的。     

氯霉素对菲律宾蛤仔的急性和亚急性毒性作用

研究了氯霉素对菲律宾蛤仔的急性和亚急性毒性作用.结果表明,菲律宾蛤仔的48,96h LD50值分别为1803,1161mg/dm3,安全浓度为58.05mg/dm3.氯霉素明显抑制菲律宾蛤仔内脏团溶菌酶活性;氯霉素明显抑制内脏团碱性磷酸酶活性,在高浓度时抑制更为明显;氯霉素可激活肌肉组织的碱性磷酸酶活性;氯霉素在高浓度时明显抑制菲律宾蛤仔内脏团及肌肉组织的过氧化氢酶活性,低浓度时抑制不明显.     

MBBR泥膜复合系统泥膜竞争关系的影响因素

为探究MBBR泥膜复合硝化系统内泥膜竞争关系，通过小试试验研究了水处理过程中常规因素（污泥浓度、DO、温度、C/N）对MBBR泥膜复合系统硝化效果的影响，分析了系统内污泥容积负荷和移动床生物膜反应器（MBBR，Moving-Bed Biofilm Reactor）生物膜容积负荷变化趋势，进而得出泥膜竞争规律.结果表明，MBBR泥膜复合系统容积负荷均大于单一污泥或MBBR生物膜系统的容积负荷.在一定范围内，污泥浓度、DO、温度与MBBR泥膜复合系统容积负荷呈现正相关，且系统内活性污泥在与MBBR生物膜在竞争DO和基质时优势明显，而MBBR生物膜则具有更强的耐低温能力.进水C/N与MBBR泥膜复合系统硝化负荷呈负相关，且活性污泥在应对进水C/N过高时较MBBR生物膜更具优势，MBBR的“镶嵌”则强化了系统SND效果.微生物群落变化显示MBBR泥膜复合系统内的硝化细菌优势菌属为Nitrospira，且悬浮载体生物膜对其富集能力明显高于活性污泥.     

Propagation functions for monitoring distributional changes

In environmental assessment and monitoring, a primary objective of the investigator is to describe the changes occurring in the environmentally important variables over time. Propagation functions have been proposed to describe the distributional changes occurring in the variable of interest at two different times. McDonald et al. (1992, 1995) proposed an estimator of propagation function under the assumption of normality. We conduct a detailed sensitivity analysis of inference based on the normal model. It turns out that this model is appropriate only for small departures from normality whereas, for moderate to large departures, both estimation and testing of hypothesis break down. Non-parametric estimation of the propagation function based on kernel density estimation is also considered and the robustness of the choice of bandwidth for kernel density estimation is investigated. Bootstrapping is employed to obtain confidence intervals for the propagation function and also to determine the critical regions for testing the significance of distributional changes between two sampling epochs. Also studied briefly is the mathematical form and graphical shape of the propagation function for some parametric bivariate families of distributions. Finally, the proposed estimation techniques are illustrated on a data set of tree ring widths.     

Acetylcholinesterase activity is affected by stress conditions in<Emphasis Type="Italic"> Paracentrotus lividus</Emphasis> coelomocytes

The presence and function of acetylcholinesterase (AChE) in blood cells and plasma is well known. The enzyme activity is associated to red blood cell membranes, as well as to the perinuclear region of leucocytes, suggesting a role in the function of the latter. Recently coelomocytes, acknowledged progenitors of immune cells in vertebrate systems, have been shown to respond to stress conditions, both in laboratory experiments and field studies. Bearing in mind the similarity between coelomocytes and vertebrate blood cells, we investigated the presence of AChE activity in coelomocytes of the sea urchin Paracentrotus lividus characterized by specific inhibitors, in relation to cold stress induced in the laboratory. Exposure to stress was followed by electrophoretic analysis of AChE activity and Western blot analysis of AChE-like immunoreactivity. Moreover, quantitative analysis of the different molecular forms of AChE was carried out with the aid of a spectrophotometric method. The effects of stress on AChE activity were time dependent. In fact, the enzyme activity was detected by the catalytic activity in cleaving the substrate acetyl thiocholine iodide, which appears to be formed by different isoforms of the enzyme, compared to that of Electrophorus, which was used as a control. Western blot analyses showed the presence of different immunoreactive molecules, with molecular mass ranging from 265 kDa (corresponding to Electrophorus molecules) to about 180 kDa. According to quantitative analysis, the isoforms that were differentiated corresponded to an AChE with the capacity to cleave acetyl--methyl thiocholine iodide (the so-called true AChE, E.C. 3.1.1.7, corresponding to the 265 kDa band) and to a ChE with the capacity to cleave propionyl thiocholine iodide as well. The latter is an ancestral form of AChE, mainly present in invertebrates. Each of these forms was affected differently by varying time exposures.Communicated by R. Cattaneo-Vietti, Genova     

两种新型杀虫剂对小鼠及蝌蚪微核形成率的影响

研究了吡虫啉和抑食肼对小鼠骨髓细胞及蝌蚪红细胞微核率的影响.实验结果表明,上述两种杀虫剂在不同的暴露系统中,呈现了不同的致突变效应.与阴性对照组相比,小鼠骨髓细胞微核形成率无显著性差异(P＞0.05),而它们对蝌蚪红细胞均呈现明显的致突变效应(P＜0.05,P＜0.01),且吡虫啉的致突变性明显高于抑食肼.     

浅析绿色社区创建措施——以长沙市芙蓉区国家级绿色社区为例

随着我国经济建设的发展，生态环境受到了一定程度的破坏，环境污染成为制约城市发展的重要问题。国家颁布文件要求全国环境保护重点城市要逐步开展创建“绿色社区”活动，培养公众良好的环境伦理道德规范，促进良好社会风尚的形成。生态学在城市社区规划和建设中的应用为社区研究提供了指导思想和理论依据。绿色社区的创建工作在全国已经蔚然成风，关于绿色社区的研究在国内外逐渐兴起，成为建筑界、城市生态学研究的热点，由于它平衡了环境保护和人类社会经济发展之间的关系．被认为是可持续发展理论在城市发展中有效可行的具体应用。本文分析了绿色社区的基本内涵，指出绿色社区以可持续发展思想为指导，体现“人与自然和谐共生”的思想，具有整体性、长期性和地域性的特点，进而阐明长沙市芙蓉区绿色社区的创建情况，最后探讨了绿色社区的创建措施和途径。     

The European Council,the Council and the Member States: changing environmental leadership dynamics in the European Union

ABSTRACT

The leadership dynamics between the European Council, the Council and the Member States in European Union (EU) environmental policy since the 1970s are analysed. The puzzle is that, although the EU was set up as a ‘leaderless Europe’, it is widely seen as an environmental leader, albeit sometimes as a one-eyed leader amongst the blind. While differentiating between leadership types, it is argued that the European Council has the largest structural, the Council the most significant entrepreneurial, and the Member States the most important cognitive and exemplary leadership capacities. Most day-to-day environmental policy measures are negotiated by the Environment Council (in collaboration with the European Parliament). The European Council’s increased interest in high politics climate change issues is largely due to the EU’s global leadership ambitions. Member States have traditionally formed environmental leadership alliances on an ad hoc basis although this may be changing.