对高校扩招有关问题的思考

高等院校扩大招生,满足了广大群众迫切希望接受高等教育的愿望,满足了社会对各种高级专门人才日益增长的需求。伴随着连续的扩招,在高教界普遍出现了基础设施不足,教育质量受到影响的现象,本文针对这一问题进行分析与探讨,并提出了改进的建议。     

Genetically Modified (GM) Crops: Precautionary Science and Conflicts of Interests

Risk governance of GM plants and GMfood products is presently subject to heatedscientific and public controversies. Scientistsand representatives of the biotechnologyindustry have dominated debates concerningsafety issues. The public is suspicious withregard to the motives of scientists, companies,and political institutions involved. Thedilemmas posed are nested, embracing valuequestions, scientific uncertainty, andcontextual issues. The obvious lack of data andinsufficient information concerning ecologicaleffects call for application of thePrecautionary Principle (PP). There are,however, divergent opinions among scientistsabout the relevance of putative hazards,definition of potential ``adverse effects,' andwhether actions should be taken to preventharm. The reliance on the concept ofsubstantial equivalence in safety evaluation ofGM food is equally controversial. Consequently,value assumptions embedded in a scientificframework may be a barrier for employment ofthe PP. One of our major conclusions is thatprecautionary GMP usage requires riskassessment criteria yet undeveloped, as well asbroader and more long-term conceptions of risk,uncertainty, and ignorance. Conflicts ofinterest and public participation are otherissues that need to be taken intoconsideration. GMP governance regimes that arejustifiable from a precautionary and ethicalpoint of view must transcend traditionalscientific boundaries to include alternativescientific perspectives as well as publicinvolvement.     

2002年我国事故与灾害状况综述

本对我国2002年的安全生产事故及自然灾害情况进行了总结和评述。包括火灾(城乡火灾、森林火灾、草原火灾)、天气气候特征、农业自然灾害(干旱、洪涝、风雹、低温冻害)、海洋灾害(风暴潮、赤潮、海浪)、地质灾害(地震、泥石流、水土流失)等。     

渭河流域生态环境对野鸭数量分布的影响

环境是动物生存的基础，人类的活动对环境所造成的影响，直接导致动物种群数量的变动。通过渭河咸阳段气候、水质、水域面积、植物等环境因素的改变对野鸭数量分布影响的调查，表明环境的恶化导致了动物的生存受到威胁，数量减少，分布区域缩小。随着环境保护意识的增强，渭河流域的水土流失，水质污染、退耕还草等环境问题逐渐得到解决，动物的生活环境不断得到改善，其种群数量、分布范围随之增加。     

长江铜陵段表层水中重金属含量及存在形态分布研究

通过测定长江铜陵段枯、丰水期江水中cu、Pb、Zn和cd不同形态的含量,分析了4种金属在江水中的存在形态分布,不同水期含量变化,水中悬浮物对金属吸附能力大小,以及近20年来含量的变化情况。结果表明,长江铜陵段江水中各重金属总量丰水期时大于枯水期,重金属各形态含量之间均有差异:丰水期时,各金属会被悬浮物以不同的方式携带进入水体中,cu、zn、Pb以活跃态和稳定态为主,Cd以活跃态为主;枯水期时,Zn主要以溶解态和稳定态为主,Pb以稳定态方式被携带,而80％的Cu、Cd是以溶解态形式存于水中。悬浮物(丰水期)对重金属的吸附能力大小顺序为Pb>Cu>Zn>Cd。与近20年江水中的重金属背景值比较,长江铜陵段重金属含量有普遍升高的趋势。     

焦化黄血盐吸收塔填料自燃原因分析

焦化黄血盐系统内的吸收塔在停产检修补充填料——铁刨花期间，经常发生铁刨花自燃现象，这是严重的事故隐患。结合武钢焦化公司黄血盐工艺特点，对其自燃原因作了详细分析，提出了避免此类事故发生的措施。     

COLD WATER PATCHES IN WARM STREAMS: PHYSICOCHEMICAL CHARACTERISTICS AND THE INFLUENCE OF SHADING1

ABSTRACT: Discrete cold water patches within the surface waters of summer warm streams afford potential thermal refuge for cold water fishes during periods of heat stress. This analysis focused on reach scale heterogeneity in water temperatures as influenced by local influx of cooler subsurface waters. Using field thermal probes and recording thermistors, we identified and characterized cold water patches (at least 3°C colder than ambient streamflow temperatures) potentially serving as thermal refugia for cold water fishes. Among 37 study sites within alluvial valleys of the Grande Ronde basin in northeastern Oregon, we identified cold water patches associated with side channels, alcoves, lateral seeps, and floodplain spring brooks. These types differed with regard to within floodplain position, area, spatial thermal range, substrate, and availability of cover for fish. Experimental shading cooled daily maximum temperatures of surface waters within cold water patches 2 to 4°C, indicating a strong influence of riparian vegetation on the expression of cold water patch thermal characteristics. Strong vertical temperature gradients associated with heating of surface layers of cold water patches exposed to solar radiation, superimposed upon vertical gradients in dissolved oxygen, can partially restrict suitable refuge volumes for stream salmonids within cold water patches.     

泥石流输沙对小江中下游河床演变的影响

对小江中下游近90km河床及两岸泥石流进行了调查研究。得到：泥石流输沙年际和季节变化大；泥石流高强度的输沙造成小江河床特殊的平面和剖面特征；泥石流堵塞小江河道，对纵比降有再造作用；泥沙使小江河床以年均20cm～50cm速度抬升。     

黄河断流成因及人文思考

日益严峻的黄河断流现象严重地影响了黄河流域经济和社会的可持续发展，也制约了西部大开发战略的实施。在分析了黄河断流的危害、成因的基础上，提出了在工程措施之外，要从人口、法律制度、产业结构等人文因素方面入手缓解黄河断流。     

长江上游森林植被变化对削洪减灾功能的影响

长江上游具有形成暴雨洪水的地形与气候条件，森林植被削洪减灾功能的提高必须着眼于森林植被—土壤生态系统结构的改善，削洪减灾功能的提高是通过林冠层、枯枝落叶层和土壤层对雨水的截留拦蓄作用实现的。研究区森林植被—土壤生态系统区域差异明显，不同地区该系统林冠层、枯枝落叶层和土壤层的最大截持水量不同，该系统削洪减灾功能的大小不仅与降雨特点有关，而且与系统各水文层前期持水量有关。在连续长时间暴雨情况下，森林植被—土壤生态系统除对第一次洪峰有削减作用外，对后续暴雨洪水的削减作用不明显，甚至会使洪峰增高。根据宜昌站30d洪水量的地区组成和森林植被—土壤生态系统截留持水功能的特点，提出了长江上游森林植被恢复、重建与保护的宏观调控对策。