Vertical diversity of sediment bacterial communities in two different trophic states of the eutrophic Lake Taihu, China

Vertical diversity of sediment bacterial communities in 2 different trophic states (macrophyte-dominated and algae-dominated) of the large shallow eutrophic Lake Taihu, China, were investigated using denaturing gradient gel electrophoresis (DGGE) and 16S rRNA sequence analysis. Clustering analysis of DGGE profiles showed that different clusters were recognized in different depths of sediment cores in the 2 lake trophic states. Analyses of the bacterial diversity, as estimated by the Shannon index (H'), showed that different sediment layers of the macrophyte-dominated state had higher diversity than the algae-dominated state. In addition, bacterial diversity of the sediment in the macrophyte-dominated state changed abruptly throughout the layers, but bacterial diversity of the algae-dominated state decreased gradually with sediment depth. Phylogenetic analysis showed that Proteobacteria was the most abundant phylum in the middle sediment of the 2 lake trophic states. In the macrophyte-dominated state, clone sequences related to Betaproteobacteria (50.0%) were the most abundant, followed by Epsilonproteobacteria (21.1%), Acidobacteria (7.9%), Deltaproteobacteria (7.9%), Chloroflexi (7.9%), and Bacteroidetes (5.3%); whereas in the algae-dominated state, sequences affiliated with Betaproteobacteria (84.4%) were predominant, followed by Deltaproteobacteria (12.5%) and Acidobacteria (3.1%). Canonical correspondence analysis showed that organic matter and pH play key roles in driving the vertical changes of bacterial community composition.     

粒级-标准偏差法和主成分因子分析法在粒度敏感因子提取中的对比

沉积物全样粒度参数已很难对受不同物源和不同沉积动力影响的古环境进行深入研究,不同来源的多组分分离提取敏感粒级方法较多,不同的方法提取的粒级兼容性及其所反映的环境意义差别值得探讨。本文利用烟台四十里湾3个柱状沉积物粒度分析数据为基础,对比分析粒级-标准偏差法和主成分因子分析法提取的环境敏感因子及其反映的古环境意义。结果表明,两种方法提取的环境敏感因子粒级一一对应,两种方法所提取的敏感粒级含量在沉积物中存在相同的变化趋势,这说明了两种方法均能敏感地反映沉积物相同的沉积动力特征,但粒级-标准偏差法所提取的粒级易受端元组分影响,粒级-标准偏差法所提取的敏感因子主要反演主控因子环境信息。     

水务企业多元化模式探讨

以在沪深两市上市的22家以涉水业务为主营业务的企业为研究样本,从战略相关多元化与非相关多元化的角度,利用优化的Jacquemin-Berry熵测度模型,定量展现了一幅水务企业多元化发展的图景。并基于核心资源与能力理论,总结了水务企业不同的多元化发展模式。研究发现,在样本企业中,存在三种主要模式:以资本运营为核心的综合多元化扩张、以技术研发为核心的战略相关多元化扩张和以非水务资源为核心的非相关多元化扩张。其中,实行综合多元化扩张的水务企业更倾向于成长为我国本土大型、综合、流域型水务集团。     

钛管的一次压扁成形工艺

此文研究了钛管装入聚胺脂芯棒后一次压扁成形的工艺特点,分析了以往空心管成形所存在的问题。在实验的基础上完成了不同规格钛合金管材的一次压扁成形。     

高职环保类专业职业技能培养课程体系开发

课程体系是高职专业办出特色、持续发展的载体。针对高职环保类专业人才培养存在课程体系不合理、实践教学薄弱、职业技能培养方法陈旧等问题，以职业岗位需求为基础，以职业技能培养为主线，构建了以实际污染治理项目为载体的高职环保类专业职业课程体系和职业核心课程。通过职业核心课程建设、双师型师资队伍建设、校内外实训基地建设等措施实现职业技能的培养。     

Research core and framework of sustainability science

This paper reviews recent achievements in sustainability science and discusses the research core and framework of sustainability science. We analyze and organize papers published in three selected core journals of sustainability science: Sustainability Science, Proceedings of the National Academy of Sciences of the United States of America, and Sustainability: Science, Practice, & Policy. Papers are organized into three categories: sustainability and its definition, domain-oriented research, and a research framework for sustainability science. First, we provide a short history and define the basic characteristics of sustainability; then we review current efforts in the following research domains: climate, biodiversity, agriculture, fishery, forestry, energy and resources, water, economic development, health, and lifestyle. Finally, we propose a research framework for sustainability science that includes the following components: goal setting, indicator setting, indicator measurement, causal chain analysis, forecasting, backcasting, and problem–solution chain analysis. We emphasize the importance of this last component for improving situations and attaining goals.     

石灰石与SO_2直接硫酸化反应宏观动力学的研究

温度、ＳＯ＿２浓度、颗粒大小、石灰石类型和样品的微观结构影响着直接硫酸化反应过程。这一反应过程能用缩芯模型来描述，并对ＳＯ＿２具有一级反应特征。本征反应和产物层扩散控制反应的活化能分别是８５．２ｋＪ／ｍｏｌ和４１．５ｋＪ／ｍｏｌ。在８００℃、２０００ｐｐｍＳＯ＿２和反应１０１ｍｉｎ的条件下，Ｉｇｚｌａｂｅｒｇａ和Ｆｏｒｓｂｙ石灰石的ＣａＣＯ＿３转化率分别可达８４％和７２％。在初始２ｍｉｎ内已煅烧石灰石（ＣａＯ）的硫酸化反应速率与石灰石的反应速率稍高，随后二者基本相同。     

An overview of short‐term tests for the mutagenic and carcinogenic potential of pesticides

Abstract

In the last few years, marked progress has been made in the development of methods for evaluating the mutagenic and carcinogenic potential of pesticide chemicals. The correlation of genetic and related biological activity in short‐term tests with carcinogenic activity in whole animals allows the utilization of short‐term mutagenicity bioassays to prescreen chemicals for effects related to mutation induction and presumptive carcinogenicity. In addition, bioassays now available can measure directly the chemical transformation of normal cells in culture into cells capable of producing tumors when injected into animals.

This paper will review briefly the major types of relevant short‐term tests and will develop a rationale for a phased approach to the evaluation of the mutagenic and carcinogenic potential of environmental chemicals. This approach involves the sequential application of bioassays which are organized into a three‐level matrix emphasizing first detection, then confirmation, and finally hazard assessment. Chemicals demonstrating positive results in the short‐term detection systems and confirmatory bioassays are pursued in higher level whole animal tests. A core battery of tests is proposed to operationally define a negative result. The phased approach should facilitate a cost effective utilization of limited testing resources and provide protection for human health in proportion to the anticipated hazard.

Results obtained in evaluating a series of thirty‐eight pesticide chemicals according to the phased approach are discussed in detail.     

带压作业闸板防喷器胶芯失效机理研究

针对带压作业过程中闸板防喷器胶芯易失效的问题,以现场使用的带压作业闸板防喷器胶芯为研究对象,通过实验确定了橡胶基体的本构关系,利用ABAQUS软件对比研究了4种不同井筒压力对胶芯的疲劳失效与密封失效的影响。结果表明:分析结果与现场应用胶芯的失效位置相符,验证了分析的正确性;胶芯的疲劳失效位置集中在橡胶基体与闸板上下部的4个尖角接触区域,上部区域失效严重;井筒压力的大小影响橡胶基体密封面上的接触应力分布,但对耐磨块密封面上接触应力分布影响不显著。建议在橡胶基体与闸板上下部的4个尖角区域补强以增加胶芯寿命。     

重庆市都市功能核心区秋季大气污染物时空分布特征

为研究重庆市都市功能核心区大气污染物浓度水平及变化规律,统计分析了2014年9月至2014年11月5个监测站(解放碑、高家花园、杨家坪、新山村和南坪)24 h连续监测PM_(2.5)、PM_(10)、SO_2、NO_2、CO和O_3浓度数据.结果表明,观测期间,大气颗粒物污染严重,5个站点PM2.5日均浓度超标率分别为30.8%、37.4%、38.5%、37.4%和31.9%,5个站点PM10日均浓度超标率分别为23.1%、22.0%、18.7%、19.8%和19.8%;重庆市都市功能核心区细颗粒物(PM_(2.5))污染严重,5个站点PM2.5占PM10比例分别为60.2%、64.6%、64.1%、75.4%和62.8%;PM_(2.5)、PM_(10)、NO_2和CO早晚出现高峰值;SO_2和O_3浓度日变化曲线呈现单峰型,峰值分别出现在中午和午后;降水量、气温和水汽压与PM_(2.5)、PM_(10)、SO_2和NO_2呈显著负相关;相对湿度与O_3呈显著负相关,气温、水汽压和风速与O_3呈显著正相关;CO与相对湿度呈显著正相关;风向也影响着大气污染物浓度的时空分布,南偏西、南偏东和东北偏北风利于PM_(2.5)、PM_(10)、SO_2、NO_2和CO浓度积累,西北风利于PM_(2.5)、PM_(10)、SO_2、NO_2和CO扩散;但西北风控制下利于O_3浓度积累.