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201.
Two balanced reciprocal translocations were found in an amniotic fluid cell culture undertaken because of maternal age. One translocation had been inherited from each parent. Both translocations were traced through three generations of each family. The importance of banding techniques in diagnostic cytogenetics is stressed.  相似文献   
202.
203.
Phytoremediation is a potential cleanup technology for the removal of heavy metals from contaminated soils.Bidens maximowicziana is a new Pb hyperaccumulator,which not only has remarkable tolerance to Pb but also extraordinary accumulation capacity for Pb.The maximum Pb concentration was 1509.3 mg/kg in roots and 2164.7 mg/kg in overground tissues.The Pb distribution order in the B. maximowicziana was:leaf>stem>root.The effect of amendments on phytoremediation was also studied.The mobility of soil Pb and the Pb concentrations in plants were both increased by EDTA application.Compared with CK(control check),EDTA application promoted translocation of Pb to overground parts of the plant.The Pb concentrations in overground parts of plants was increased from 24.23-680.56 mg/kg to 29.07-1905.57 mg/kg.This research demonstrated that B.maximowicziana appeared to be suitable for phytoremediation of Pb contaminated soil,especially,combination with EDTA.  相似文献   
204.
随着纳米技术迅猛发展,纳米颗粒的环境行为和生态效应越来越受到关注.纳米氧化物作为环境中的重要组成,广泛存在于水体、大气、土壤以及沉积物中,其大比表面积和高表面活性,控制和影响着环境中一些污染物和营养元素的形态、迁移、转化和生物有效性.纳米尺寸是纳米颗粒特有属性,颗粒尺寸大小调控和决定纳米氧化物的结构及物理化学特性,从而在较大程度上影响其与相关元素的界面反应性和环境地球化学行为.综述了纳米氧化物的尺寸对吸附、(还原)溶解、(催化)氧化、聚集和迁移等环境行为的影响,讨论了尺寸效应的作用机制,最后展望了环境中纳米金属氧化物尺寸效应有关的研究热点和方向.  相似文献   
205.
水环境中的邻苯二甲酸酯类污染物及其环境行为研究   总被引:3,自引:0,他引:3  
邻苯二甲酸酯是一类普遍使用的有机化合物质,主要用于聚氯乙烯的增塑剂,目前在水环境中已经大量存在,由于其具有致癌、致畸和致突变性,引起广泛的关注。已有研究表明,邻苯二甲酸酯环境内分泌于扰物,对人类和自然环境有非常大的危害。文章主要对邻苯二甲酸酯类污染物在水环境中的污染现状以及水环境行为的研究现状进行了综述,进入水环境的邻苯二甲酸酯主要是在水体中发生相应的迁移转化,邻苯二甲酸酯能够在水环境中发生生物降解、吸附、水解和光解等环境行为。最后对邻苯二甲酸酯类污染物今后的研究方向进行了展望。  相似文献   
206.
Pro-environmental behaviors are an important avenue for mitigating environmental impacts. Technological improvements are also a vital tool for reducing environmental damage from consumption. However, their benefits are partially offset by the direct rebound effect, whereby a consumer rationally responds to an increase in resource use efficiency by consuming more. This paper investigates whether technological improvement might also reduce behaviorally motivated mitigation of environmental damage. A behavioral rebound effect operates through two channels. First, pro-environmental effort is reduced after a decrease in marginal environmental damage. Second, moral licensing reduces pro-environmental effort further when technological change is endogenous. I develop a novel real effort laboratory experiment to identify these behaviors. I find a positive behavioral rebound effect. I also find evidence consistent with moral licensing, which is strongest among subjects with a higher degree of pro-environmental attitudes and beliefs. Subjects’ baseline level of pro-environmental effort is driven by beliefs about social norms.  相似文献   
207.
王翰钊    李守国    段鹏飞    贾宝山    刘昭  耿晓伟   《中国安全生产科学技术》2016,12(4):25-29
针对神东矿区大柳塔煤矿52304工作面通过风积沙较厚区域时强烈的矿压显现现象,通过理论分析与物理相似模型以及现场测试等方法,建立工作面过风积沙区域时的力学模型,分析风积沙厚度对大采高工作面矿压显现规律的影响,对风积沙厚度对工作面关键层力学稳定性做出分析,并通过数值模拟对影响性进行研究。研究结果表明:风积沙厚度较大的开采区域,作用在覆岩主关键层结构上的载荷较大,造成主关键层破断块体的结构回转变形失稳,造成工作面矿压显现极强烈;大采高和风积沙厚度较大条件下距煤层较远的主关键层破断运动也会对工作面矿压显现产生影响,且采高、厚风积沙因素缺少其中一个时,主关键层均不会对工作面矿压产生明显影响。  相似文献   
208.
The present study deals with metal uptake by Brassica juncea in the presence of Pseudomonas fluorescens Pf 27 for Zn, Cu and Cd removal from brass and electroplating-industry effluent-contaminated soil. Inoculation of P. fluorescens significantly (p<0.05) increased water soluble (Ws) and exchangeable (Ex) metal content in contaminated soil in laboratory conditions and also enhanced plant biomass by 99% and chlorophyll content by 91% as compared to uninoculated plants in the greenhouse. The metal uptake by B. juncea followed the pattern Zn>Cu>Cd and increased with increasing plant growth duration. P. fluorescens inoculation increased root and shoot uptake of Zn by 3.05 and 2.69, Cu by 3.19 and 2.82 and Cd by 3.11- and 2.75-fold, respectively. BCF value for each metal was>1 and increased by 44%, 42% and 38% for Zn, Cu and Cd, respectively, in inoculated conditions, whereas TF remained unaffected and followed the order Zn>Cd>Cu. P. fluorescens inoculation also enhanced Ws fraction of Zn, Cu and Cd by 99%, 77% and 90% and Ex by 107%, 70% and 93%, respectively. Results depicted that association of B. juncea with P. fluorescens could be a promising strategy for enhancing soil metal bioavailability and plant growth for successful phytoremediation of heavy metal contaminated soils.  相似文献   
209.
刘颖茹  陈同斌  黄泽春  廖晓勇 《环境科学》2005,26(5):181-181-186
以As超富集植物蜈蚣草广泛分布的湖南省郴州市为例,调查了不同As污染程度下植物对As的富集和转运特点.结果表明,在野外条件下根际土壤中As浓度相对较低时(64~1000mg/kg),蜈蚣草地上部As浓度随根际土壤中As浓度的增加而逐渐增加,而在根际土壤中As浓度相对较高(1000~2712mg/kg)时,蜈蚣草地上部As浓度表现为逐渐下降的趋势.在调查的所有样点中,蜈蚣草对As的转运系数介于1.08到6.03之间,显示出超富集植物的典型特征.结果还表明,在污染区土壤As浓度存在很大的空间变异性,根际土壤与非根际土壤之间的As浓度也存在很大差异.因此,在野外调查时最好是直接采取距离植物根部最近的根际土壤.  相似文献   
210.
Drawing from the social cognitive theory of self‐regulation, we develop a model linking experienced incivility to emotional exhaustion and supportive behaviors via self‐blame, with observed incivility experienced by coworkers as a first‐stage moderator and trait emotional control as a second‐stage moderator. We contend that employees will experience self‐blame if they perceive themselves to be distinct targets of incivility (i.e., observed incivility experienced by others is low). Self‐blame can potentially trigger prosocial responses for improving the situation, but self‐blaming targets rarely respond in a prosocial manner because rational attempts to do so are thwarted by deleterious negative emotions accompanying self‐blame. We argue that trait emotional control provides resources for managing these negative emotions to unleash a bright side of self‐blame, such that the relation of self‐blame with prosocial responses (i.e., being supportive to coworkers) will be more positive and the relation of self‐blame with emotional exhaustion will be less positive for individuals with high (vs. low) trait emotional control. Multiwave data collected from a sample of 220 police officers largely support our hypotheses, indicating that the indirect relation of experienced incivility with supportive behaviors via self‐blame is strongest at lower levels of observed incivility and higher levels of emotional control.  相似文献   
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