Effects of chitosan on growth of an aquatic plant (Hydrilla verticillata) in polluted waters with different chemical oxygen demands

Effects of chitosan on a submersed plant, Hydrilla verticillata, were investigated. Results indicated that H. venicillata could prevent ultrastructure phytotoxicities and oxidativereaction from polluted water with high chemical oxygen demand (COD). Superoxide dismutase (SOD) activity and malondialdehyde (MDA) contents in H. verticillata treated with 0.1% chitosan in wastewater increased with high COD (980 mg/L) and decreased with low COD (63 mg/L), respectively. Ultrastructural analysis showed that the stroma and grana of chloroplast basically remained normal. However, plant cells from the control experiment (untreated with chitosan) were vacuolated and the cell interval increased. The relict of protoplast moved to the center, with cells tending to disjoint. Our findings indicate that wastewater with high COD concentration can cause a substantial damage to submersed plant, nevertheless, chitosan probably could alleviate the membrane lipid peroxidization and ultrastructure phytotoxicities, and protect plant cells from stress of high COD concentration polluted water.     

京九线淮滨-光山段路基病害及其防治对策

以京九线淮滨-光山段路基为例,通过现场调研,综合分析了该段路基病害的类型及其成因,并结合典型工点,重点研究了各种病害的整治方法,提出了路基病害的防治对策.     

公众参与对区域环境治理绩效影响机制的实证研究

本文利用2011—2015年我国省际面板数据,通过主成分分析法构造区域环境污染指标以衡量区域环境治理绩效,进而建立面板数据模型,实证分析了三种公众环境参与方式(即投诉上访、献言建策和自媒体舆论)对区域环境治理绩效的直接和间接影响,以期为构建政府—企业—公众多元共治的环境治理体系提出建议。实证结果表明,我国公众环境参与对提升区域环境治理绩效有一定的积极作用,自媒体舆论对区域环境治理绩效的直接影响最大。同时,我国公众主要是通过参与并监督政府环境行政规制提升区域环境治理绩效,在参与地方政府环境法律政策的制定和实施,以及驱动地方政府环保资金投入方面尚有不足。因此,本文提出提升区域环境治理绩效的三点建议:创建公众环境参与政法平台,健全公众环境参与自媒体方式,增加环境治理的环保投资。     

New insights into the benefits of flood warnings: Results from a household survey in England and Wales

The flood defence agency in England and Wales has been pursuing a programme of flood warning system enhancement, engaging householders at risk in improving their warning responses. The immediate aim of this paper is to test and revise a model of economic benefits of warnings, but the survey data also generate insights into the constraints acting upon flood warning responses. Damage saving is less than previously anticipated: warning reliability and householder availability problems limit savings. Warnings are less likely to be received by those in lower social grades, and flood warning lead time is a factor in avoiding damage. The survey data indicate the complexities involved in improving flood warning response, and provide policy pointers.     

火灾直接财产损失评估移动终端系统软件结构设计

介绍了一种基于嵌入式PDA设备的专业系统＂火灾直接财产损失评估移动终端系统＂的软件结构设计过程。该软件以公安部发布的公共安全行业标准《火灾直接财产损失统计方法》GA185—1998为计算依据,解决了嵌入式PDA设备的软件开发和编制问题,可用于房屋建筑、设备及其他财产和文物建筑的火灾损失计算和统计,并可生成数据文件,用于与之相匹配的＂火灾直接财产损失评估PC系统＂中进行统计和汇总,可随时随地地在火灾现场方便地进行直接财产损失计算和统计,能给消防工作人员带来很大便利。     

黄淮地区冬小麦霜冻灾害风险评估

黄淮地区是我国主要粮食作物冬小麦的主产区,易受霜冻灾害的影响,研究该区的霜冻灾害风险对保障我国粮食安全具有现实意义。结合分区的冬小麦物候期及其霜冻指标,以该地区56个气象站点1951—2005年日最低气温为基础数据,提取霜冻日记录。并基于年霜日数-年减产率曲线,以信息扩散理论为指导,通过IDW插值得到减产率≥10%、2...     

2004-2005年黄淮海地区冬小麦冻害成因分析

以北京、天津、菏泽、驻马店、商丘、阜阳6个站点为代表,分析了黄淮海平原2004-2005年冬季冬小麦的冻害成因.研究表明,冬小麦冻害的发生主要是由于从小麦播种至当年12月20日积温过高,造成部分麦田在入冬前就完成了6-8片叶的生长,甚至进入了拔节期,再加上从当年12月20日至次年2月底黄淮海大部分地区气温比常年偏低1.3℃左右,且冷暖交替突变,麦苗抗寒锻炼不足,春性品种过多和播种量过大等原因.     

Genotoxicity monitoring of freshwater environments using caged crayfish (Astacus leptodactylus)

Genotoxicity of freshwater pollution was assessed by measuring DNA damage in haemocytes of caged freshwater crayfish Astacus leptodactylus by the means of Comet assay and micronucleus test, integrated with the measurements of physiological (total protein concentration) and immunological (total haemocyte count) haemolymph parameters as biomarkers of undergone stress. Crayfish were collected at the reference site (River Mre?nica) and exposed in cages for 1 week at three polluted sites along the Sava River (Zagreb, Sisak, Krapje). The long term pollution status of these locations was confirmed by chemical analyses of sediments. Statistically significant increase in DNA damage measured by the Comet assay was observed at all three polluted sites comparing to the crayfish from reference site. In addition, native crayfish from the mildly polluted site (Krapje) cage-exposed on another polluted site (Zagreb) showed lower DNA damage than crayfish from the reference site exposed at the same location indicating adaptation and acclimatisation of crayfish to lower levels of pollution. Micronuclei induction showed similar gradient of DNA damage as Comet assay, but did not reach the statistical significance. Observed increase in total haemocyte count and total protein content in crayfish from polluted environments in the Sava River also confirmed stress caused by exposure to pollution. The results of this study have proved the applicability of caging exposure of freshwater crayfish A. leptodactylus in environmental genotoxicity monitoring using Comet assay and micronucleus test.     

工业控制系统的雷电灾害防护技术研究

以ICGS雷电冲击试验平台为例介绍了工业控制系统的典型结构,根据其结构的电气特点及雷电造成危害的可能途径,对工业控制系统的雷电防护提出全面具体的技术措施,从而保证工业控制系统正常安全的运行,免受电磁脉冲干扰的危害。经研究,对工业控制系统的防雷保护不仅要做好接闪器,引下线,接地体等基本的外部防护,还要做好等电位联结,屏蔽,信号系统和电源系统的电涌保护等相关内部防雷措施。     

冬小麦品种抗霜力鉴定与霜冻害防御新对策

冬小麦发育进入拔节期和出现霜冻低温是形成其霜冻害的两个要素。霜冻低温的出现主要与气候因素有关。而拔节期的早晚则受初春气温、播种期和选用品种等多种因素的影响。影响品种抗霜力的重要因素是幼穗分化时期。品种抗霜力的鉴定必须在相同的幼穗分化期,建议在药隔期进行。品种的抗霜力还与第1茎节的长度有关,而与抗冻力和叶片可溶性糖含量的相关性不显著。通过研究,提出了下列抗霜对策:在把握地区霜冻温度出现规律的基础上,合理规划抗霜品种与避霜品种的布局;通过常规育种和基因工程手段,改良品种的抗霜力;通过遗传操作磷脂酶D基因,改良冬小麦的抗霜性。