井冈山猴头杜鹃群落特征的研究

以井冈山猴头杜鹃（Rhododendron simiarum）群落5个样地调查资料为基础,对该群落的物种组成、区系成分、群落结构和物种多样性进行了研究,结果表明：群落有维管植物30科43属50种,其中蕨类植物有5科6属6种,裸子植物4科4属4种,被子植物21科33属40种。区系分析显示该植物区系起源古老,地理成分复杂,以热带性成分为主,温带性成分占有一定的比例。群落为复层异龄结构,猴头杜鹃、甜槠（Castanopsis eyrei）、福建柏（Fokienia hodginsii）、台湾松（Pinus taiwanensis）、薯豆（Elaeocarpus japonicus）和白豆杉（Pseudotaxus chienii）为群落的建群种。除Pielou指数外,群落物种多样性指数较低,各样地间多样性指数测值变幅较大;测度猴头杜鹃群落物种多样性时,各种多样性指数基本表现出相同的趋势;总体来看,猴头杜鹃群落物种多样性在群落不同层次的变化规律为：灌木层〉乔木层〉草本层。     

Distribution and source of polycyclic aromatic hydrocarbons (PAHs) in the surface soil along main transportation routes in Jiaxing City, China

Polycyclic aromatic hydrocarbons (16 EPA-PAHs) in urban surface soil from Jiaxing City were determined using HPLC. The total concentration of 16 EPA-PAHs was detected from 18.73 to 441.34 pg/g. Individual PAH occupation analysis demonstrates that four-ring PAHs comprise as much as 44.16% and were prevalent in the composition of PAH pollutants. The other components were two-ring PAHs (7.36%), three-ring PAHs (17.28%), five-ring PAHs (16.16%), and six-ring PAHs (15.04%). Source analysis on the characteristic ratios of anthracene(Ane)/[Ane+phenanthrene(Phe)], fluoranthene(Fla)/[Fla+pyrene(Pyr)], and benzo[a]pyrene(Bap)/benzo[g,h,i]perylene(Bgp) reveals that PAH pollutants originated mainly from coal combustion, but vehicular emission as a source was not negligible. All PAHs discussed in the paper have similar source in most sampling sites. The spatial distributions of pollution sources were closely related to geographic location, geographic condition, and living habit of indigenes. A linear relationship between 2-3-ring PAHs, 4-6-ring PAHs, SOM, and ∑PAHs were investigated and significant correlativity were expatiated lastly. It revealed that coefficient between 2-3-ring PAHs and ∑PAHs is 0.56, between 4-6-ring PAHs and ∑PAHs is 0.99, between SOM and ∑PAHs is 0.82.     

温度对硝化杆菌(Nitrobacter)活性动力学影响

为探究温度对亚硝酸盐氧化细菌中硝化杆菌属(Nitrobacter)活性动力学影响,本试验采用序批式活性污泥(SBR)反应器,在通过改变系统进水亚硝态氮(NO_2~--N)浓度达到富集Nitrobacter基础上,以富含Nitrobacter污泥为对象(宏基因组物种注释和丰度分析显示Nitrobacter占细菌总数40. 3%),考察不同NO_2~--N浓度梯度下亚硝酸盐氧化过程比亚硝态氮氧化速率(SNi OR)变化规律,基于Monod模型考察系统温度对Nitrobacter活性动力学影响,并进行统计学分析.结果表明,30℃条件下SNi OR达到最大(以N/VSS计),为1. 31 g·(g·d)~(-1).统计学分析结果显示,Monod方程可较好地反映不同温度条件下基质底物浓度对Nitrobacter活性影响.基于菲尔普斯方程计算不同温度区间内温度系数(θ)可知,当系统温度低于25℃或高于30℃时,反应速率随温度变化越敏感.     

淄博市雷电灾害易损性风险评估及区划

从雷电灾害易损性分析角度出发,利用山东省淄博市8个气象台站1963-2012年雷暴日资料和2002-2012年雷电灾害资料,结合各区县的经济和人口密度特征,选取雷击大地密度、雷电灾害频度、经济易损模数、生命易损模数4个指标,对淄博市雷电灾害易损性进行了评估。结果显示：张店区、淄川区是极高易损区,沂源县、临淄区为高易损区,博山区、周村区是中易损区,桓台县为低易损区,高青县为极低易损区。初步形成了各地易损性结构和淄博市雷电灾害易损度区划图,为各级政府和相关管理部门指导城市规划、防御和减轻雷电灾害提供了客观的科学依据。     

抗生素在沉积物中的吸附机制及其影响因素

抗生素作为医疗业和农业使用量最大的药物之一,由于其本身的特性,很容易进入沉积物一水环境中。抗生素在沉积物中的吸附过程是影响抗生素的反应活性、可移动性、持久性及生物可利用性的关键过程。本文选择四环素类、喹诺酮类、磺胺类和大环内酯类4类常用抗生素,在总结了这4类抗生素在湖泊沉积物中污染状况的基础上,分析了抗生素在沉积物中的吸附机制,并归纳论述了pH值、盐度、重金属离子、表面活性剂以及水动力条件对其在沉积物上吸附的影响机制。     

西溪湿地底泥质量现状与生态风险初步评价

为了解西溪湿地底泥质量现状,2012年9月采集保护区内不同干扰类型的底泥样本,测试了底泥中重金属和POPs中PCBs、OCPs和PAHs的含量,并对湿地底泥污染进行了生态风险初步评价。结果表明,底泥中未检出PCBs和OCPs,但检测出14种EPA优控PAHs,总PAHs的浓度范围为115.9～217.8 ng·g^-1,低于潜在生态风险的效应区间低值ERL,其中列入中国＂水中优先控制污染黑名单＂的7种PAHs均有检出并且其总量占∑PAHs 1/2左右（平均为50.08%）;底泥中8种重金属含量平均值低于《土壤环境质量标准》（GB 15618—1995）的二级标准,但Hg、Zn、Pb、Ni含量在多个位点已超过一级标准;分别采用土壤背景值和国家一级标准为参比值对湿地底泥中重金属进行单因子污染风险指数评价,发现分别有7种和4种元素的污染指数大于1;综合分析不同干扰类型的底泥质量,发现底泥疏浚能有效降低有机质含量、全氮和PAHs含量,但对全磷、重金属含量则无明显效果,封闭水体的干塘措施能显著减少污泥量和有机物含量。研究结果表明,西溪湿地底泥中高环PAHs和重金属污染水平可能对西溪湿地生物具有潜在的生物毒性作用及不利的生态影响效应,其疏浚底泥农用则无生态风险。     

Amniocentesis rate and the detection of down syndrome and other chromosomal anomalies in Israel

We investigated the contribution of different screening criteria to the prenatal detection of Down syndrome (DS) as well as other chromosomal anomalies in the Jewish population in Israel during 1990 and 1992. There was a significant decrease (P<0·03) in the incidence of DS live-births during 1992 (40:78 442) compared with 1990 (69:73 751) which paralleled a marked increase in total prenatal testing and in DS cases detected prenatally. Private laboratories, which perform amniocenteses mostly for women with a low risk of DS and without genetic counselling, had a significantly lower detection rate (1:917) compared with that of the genetic institutes, which following genetic counselling test both women ≥ 37 years of age (1:91) and women younger than 37 years (1:113). The detection of chromosomal anomalies other than DS was less affected by the reason for amniocentesis. Amniocentesis indicated by maternal serum marker screening of women younger than 37 years identified a greater number of chromosomal anomalies other than DS than amniocentesis based on age (≥37 years) alone (111:9604 versus 94:9810; P<0·06). Prenatal detection of DS is most effective when the indication for amniocentesis follows genetic counselling. The increasing use of maternal serum marker screening leads to a significant improvement in the positive detection rate of chromosomal anomalies other than DS in young women.     

Residential satisfaction in council housing

Planners' and architects' knowledge of the needs of users as well as their perceptions of the residential environment, has been commented on in many studies dealing with residential satisfaction. In this study—based on primary research in an area of council housing in Madrid—the main goal is the study of objective and subjective factors, on both physical and social levels, which influence council housing residents' satisfaction. A sample of 447 housewives responded to a questionaire, a multiple regression analysis of which showed that attachment to the neighbourhood and relationships with neighbours explained the greatest variance in residential satisfaction. Some methodological issues about the measurement of residential satisfaction are also discussed.     

生态公益林建设管理的环境经济政策分析--以广州市为例

根据环境经济学的外部性理论 ,生态公益林建设管理具有外部经济性。使生态公益林建设管理外部性内部化的主要手段是“调节市场”型的环境经济政策 ,即由政府向公众征收生态公益林建设管理费用 ,而“建立市场”型的环境经济政策———明晰生态公益林的产权、承包经营权 ,则是生态公益林建设管理外部性内部化和生态公益林有效管理的需要。广州市生态公益林建设管理中存在的建设管理资金不足、林地的使用权分散、对林农补偿的数量难以确定等问题 ,有待于上述两种环境经济政策来解决     

Monitoring trihalomethanes in water by differential ultraviolet spectroscopy

Ultraviolet (UV) spectroscopy is a valid surrogate for monitoring the formation of disinfection by-products (DBPs). Sodium thiosulphate is commonly used to remove disinfectant residual. However, it produces interferences with absorbance in the UV region. Relationship between trihalomethane (THM) formation and differential UV absorbance (−ΔA _λ ) was explored in the presence of sodium thiosulphate. Chlorination of two synthetic and five natural waters was carried out. Sodium thiosulphate showed high UV absorption at 254 nm. This effect can be overcome selecting a higher wavelength. Optimum wavelength varied being about 290 nm for fulvic acid and 300 nm for humic acid type natural organic matter. Correlation between THMs formation and −ΔA _λ was linear for all the analysed samples. Regression curves do not pass through zero indicating the existence of a threshold absorbance decreasment. Once it is surpassed THM release begins. Chlorination of surface waters showed that the presence of bromide significantly increases THMs vs. −ΔA _λ slope. Furthermore, slope decreased with the aromaticity–hydrophobicity of organic matter.