巢湖和太湖微囊藻毒素差异性研究

采用固相萃取高效液相色谱法检测巢湖和太湖水体中5种微囊藻毒素(MCs)——MC-RR、MC-YR、MC-LR、MC-LA、MC-LY的含量。结果表明,巢湖水体中的MCs以MC-RR、MC-LA、MC-LY为主,太湖水体主要以MC-RR、MC-LR、MC-LA为主,其中太湖MC-LR的最高质量浓度为2.558μg/L,超过《地表水环境质量标准》(GB 3838—2002)中对集中式生活饮用水地表水源地的限定值(1μg/L)。分析巢湖和太湖水体中MCs与水质指标之间的相关性,发现同种MCs与两湖环境因子的相关性存在明显差异。逐步回归拟合结果表明,氨氮和DO分别能与巢湖MC-LR、MC-LY进行拟合;Chl-a、TOC能与太湖MC-LR回归拟合,TOC能与太湖MC-YR进行拟合。由于多数MCs不能通过水质指标的拟合结果来预测,因此在未来研究中需结合环境因子和MCs的遗传机制来共同分析MCs在水中的分布规律。     

人力资本、社会资本与市民化抑制

新生代农民工问题的终结是市民化,但是目前许多新生代农民工存在市民化阻碍,这不利于我国城市化进程的推进和经济的持续健康发展。对沈阳和余姚两地区进行了案例调查,得到了两地区新生代农民工的调查数据。运用调查数据,首先采用需求可识别的biprobit模型对新生代的农民工市民化抑制程度进行了测度,并预测出新生代农民工个体的市民化抑制程度。在对新生代农民工个体的市民化抑制程度指标进行分位数回归分解的基础上,分析了人力资本和社会资本对新生代农民工市民化抑制程度的影响,以期促进新生代农民工的城市融入。研究发现:新生代农民工的社会资本水平是影响其市民化的关键因素,人力资本水平的提高只有在市民化抑制程度高于80%时才会使市民化抑制程度下降。因此,相应的政策建议为,政府应加强新生代农民工城市公共服务的享用水平;发展和健全农民工工会组织;在市民化抑制程度较高的地区应特别加强新生代农民工职业技能的培训。     

CLUE-S模型对村镇土地利用变化的模拟与精度评价

利用航片、IKONOS和Quickbird影像得到研究区3期（1991、2001和2009年）土地利用历史数据,运用CLUE S模型,基于1991、2001年的土地利用数据对2009年土地利用格局进行模拟预测,并将模拟结果与2009年真实土地利用数据进行比较。类型水平上,选择ROC曲线统计和偏离度指数分别对各地类的Logistic回归拟合精度和CLUE S模型模拟精度进行评价;景观水平上,采用景观指数和Kappa指数系列方法,从综合预测能力、景观格局、数量和空间位置等方面对CLUE S模型的模拟精度进行全面评估。结果表明:①CLUE S模型对各土地利用类型的模拟精度均较高,各地类的Logistic回归的拟合精度随着模拟分辨率的提高而逐渐增加;②随着模拟时间的缩短,CLUE S模型对整体景观格局的模拟精度提高;③该模型对土地利用数量的模拟精度明显优于其对空间位置的模拟精度。总体而言,CLUE S模型在村镇尺度的模拟效果良好,预测精度较高,但在空间位置和景观格局精度方面还有待提高     

基于产业链的区域环境污染物排放的产业贡献

区域经济增长与环境质量之间的关系研究是目前学者们探讨的重要学术议题之一.其中较多的是对EKC曲线的验证,近几年部分学者从国民经济各部门中的产业自身特征、产业结构、技术进步、FDI效应等方面考察产业发展对污染物排放的影响.然而以上研究议题中学者均没有讨论污染物的发生主体-各产业部门与排污的直接关系.故本文将从宏观尺度下的综合水平测度区域经济发展与环境质量关系、中观尺度下的产业属性特征与排污关系的研究视角转移至分析具体产业部门的污染物排放效应,同时将产业置于产业链的结构形式中,研究产业链上产业发展与污染物排放的关系.发现:第一,通过借助复杂网络思想的社区划分方法,将山东省39个产业部门分为3个社团.其中社团I主要由制造业部门组成,共有18个产业部门,社团II包括了15个部门,主要是第三产业,杜团III由6个产业部门组成且内部异质性高.第二,选择其中以制造业为主的社团I,并在社团I内识别出一条彼此间联系最为紧密的产业链,包括农林牧渔业、食品制造及烟草加工业、化学工业、纺织工业、服装皮革羽绒及其制品业、通用/专用设备制造业和交通运输设备制造业.以一种定量的方法获取了通过价值流传递而串在一起的产业链条.该产业链的经济规模、污染物规模在山东省均有重要地位.第三,采用岭回归分析方法,构建了6个制造业与产业链工业废水、固体废弃物排放的关系模型,6个制造业中对工业废水、固体废弃物排放相对贡献度最大的部门分别为服装皮革羽绒及其制品业、食品制造及烟草加工业.这是由于上游产业排污的链式传递效应与产业自身污染物排放效应的共同叠加作用.     

中国省际能源效率差异及其影响因素分析

我国省际能源效率存在较大的差异.要进一步促进能源综合利用,需要在区域层面对能源效率差异形成的因素作更加全面深入的研究,以寻求更加合理有效的促进宏观能源效率改进的理论与方法.本文基于2007年的截面数据,运用能很好地消除各因素间多重共线性的偏最小二乘回归建模,选取了14个变量来代表经济发展水平、产业结构、工业结构、能源消费结构、对外开放程度、投资水平、政府影响力、制度因素、能源价格和地理因素这10个因素,分析了各因素对能源效率地区差异的影响方向和影响程度.研究结果表明,各地区固定资产投资中外商投资比重、工业增加值中高耗能产业比重以及煤炭消费比重的差异是造成能源效率地区差异显著的主要原因.这说明投资水平、工业结构和能源消费结构是造成能源效率地区差异显著的主要因素.要在短期内缩小地区间的能源效率差距,必须严格限制某些地区高耗能行业的过快发展,加强高耗能行业的结构调整,加快淘汰落后产能,大力提升煤炭的使用效率.     

民族地区农村信息化与农民收入关系研究——基于恩施州利川市调研结果的实证分析

运用对国家民委的863科技项目推广点之一的湖北恩施自治州利川市的调研数据,采用多变量回归和Logistic回归模型对信息化与农村经济发展、特别是与农民收入之间的关系进行实证分析,结果表明:信息化与农民收入有着正相关的关系;农民的收入结构与信息化、农民的文化程度也有着密切的关系。     

Model evaluation of the phytoextraction potential of heavy metal hyperaccumulators and non-hyperaccumulators

Evaluation of the remediation ability of zinc/cadmium in hyper- and non-hyperaccumulator plant species through greenhouse studies is limited. To bridge the gap between greenhouse studies and field applications for phytoextraction, we used published data to examine the partitioning of heavy metals between plants and soil (defined as the bioconcentration factor). We compared the remediation ability of the Zn/Cd hyperaccumulators Thlaspi caerulescens and Arabidopsis halleri and the non-hyperaccumulators Nicotiana tabacum and Brassica juncea using a hierarchical linear model (HLM). A recursive algorithm was then used to evaluate how many harvest cycles were required to clean a contaminated site to meet Taiwan Environmental Protection Agency regulations. Despite the high bioconcentration factor of both hyperaccumulators, metal removal was still limited because of the plants' small biomass. Simulation with N. tabacum and the Cadmium model suggests further study and development of plants with high biomass and improved phytoextraction potential for use in environmental cleanup.     

An analysis of assessment outcomes from eight years' operation of the Australian border weed risk assessment system

The majority of Australian weeds are exotic plant species that were intentionally introduced for a variety of horticultural and agricultural purposes. A border weed risk assessment system (WRA) was implemented in 1997 in order to reduce the high economic costs and massive environmental damage associated with introducing serious weeds. We review the behaviour of this system with regard to eight years of data collected from the assessment of species proposed for importation or held within genetic resource centres in Australia. From a taxonomic perspective, species from the Chenopodiaceae and Poaceae were most likely to be rejected and those from the Arecaceae and Flacourtiaceae were most likely to be accepted. Dendrogram analysis and classification and regression tree (TREE) models were also used to analyse the data. The latter revealed that a small subset of the 35 variables assessed was highly associated with the outcome of the original assessment. The TREE model examining all of the data contained just five variables: unintentional human dispersal, congeneric weed, weed elsewhere, tolerates or benefits from mutilation, cultivation or fire, and reproduction by vegetative propagation. It gave the same outcome as the full WRA model for 71% of species. Weed elsewhere was not the first splitting variable in this model, indicating that the WRA has a capacity for capturing species that have no history of weediness. A reduced TREE model (in which human-mediated variables had been removed) contained four variables: broad climate suitability, reproduction in less or than equal to 1year, self-fertilisation, and tolerates and benefits from mutilation, cultivation or fire. It yielded the same outcome as the full WRA model for 65% of species. Data inconsistencies and the relative importance of questions are discussed, with some recommendations made for improving the use of the system.     

Land use planning and wildfire risk mitigation: an analysis of wildfire-burned subdivisions using high-resolution remote sensing imagery and GIS data

This paper evaluates risk factors that influence the probability that a house will burn from wildfire. A logistic regression is used to analyse data processed from pre-fire and post-fire IKONOS images and other geo-referenced data. The dependent variable is the probability that a given house will burn. A total of 12 independent variables are evaluated: vegetation density; area of defensible space; adjacency of a parcel to public lands; proximity of a house to fire station; road width; road type; parcel size; subdivision morphology; assessed value; elevation; slope and aspect. Model results generally support dominant land use planning and design strategies for wildfire risk reduction including vegetation treatments, site selection with respect to topography, and improving access to fire stations.     

降低循环冷却水水耗的生产措施

为了有效降低循环冷却水系统补充水量、排污量,节约水处理剂的消耗、降低冷却水处理成本,关键在于提高循环水的浓缩倍数。本文对影响循环水浓缩倍数的因素进行了分析,总结了哈尔滨石化公司循环水场存在的问题。同时本文给出了提高循环水浓缩倍数的方法,上述方法能取得显著的环境效益和经济效益。