快速评估近岸海洋水体与沉积物中E.coli与S.aureus抗生素抗性水平的新方法

随着抗生素抗性污染日益严重,快速评估环境中典型病原菌与条件性致病菌的抗生素抗性水平,对掌握区域环境抗生素抗性污染状况、揭示抗性污染传播规律至关重要。通过以最低抑菌浓度浸入抗生素改进MI、VJ培养基,并结合滤膜法,建立了针对近岸海洋环境中指示性病原微生物大肠杆菌(Escherichia coli,E.coli)与金黄色葡萄球菌(Staphylococcus aureus,S.aureus)的抗生素抗性监测方法。水体和沉积物样品抗生素抗性水平评估实验结果显示,该方法具有较好重现性(水体和沉积物中E.coli和S.aureus抗生素抗性水平的相对标准偏差分别为11%、8%)与准确度(水体和沉积物中E.coli和S.aureus的平均回收率分别为83.5%、68.4%;相对于CLSI药敏试验的偏离度为±0.1)。且与CLSI药敏实验相比,该方法过程简便、耗时短(36 h/84 h),能最大限度节约经济和人员成本提高抗性评价效率。应用该方法评估辽河口与莱州湾环境中2种病原微生物磺胺类抗生素抗性水平,结果显示辽河口水体中E.coli和S.aureus磺胺二甲嘧啶的平均抗性率分别为27.0%、28.4%,沉积物中分别为35.5%、34.6%;莱州湾水体中E.coli和S.aureus磺胺二甲嘧啶的平均抗性率分别为26.0%、14.5%,沉积物中分别为12.0%、32.9%。该方法适用于河口、近岸海洋及入海排污口水体与沉积物样品中E.coli与S.aureus的快速分析及抗生素抗性水平评估。     

Simulation and Trend Analysis of the Water Quality Monitoring Daily Data in Nestos River Delta. Contribution to the Sustainable Management and Results for the Years 2000–2002

The transboundary River Nestos in the Balkan Peninsula is a surface water resource shared by Hellas and Bulgaria. The Public Power Corporation of Hellas (DEH) proceeded to the dams' construction of Thesaurus in 1997 and Platanovrissi in 2000, to satisfy the increased needs for power production and irrigation in the Regions of Eastern Macedonia and Thrace in the Hellenic Territory. DEH following the Ministerial Agreement of the Hellenic Parliament ‘`KYA 18492/19—09—1996’' funded a series of Research Projects concerned on the monitoring of the water quantity and quality data of Nestos from the Hellenic-Bulgarian borders to its estuaries in the Thracian sea. ‘`PERSEAS’' Research Group from Aristotle University of Thessaloniki, carried out the research, design, construction, installation, operation and maintenance of the ‘`R.E.MO.S.’' (Remote Environmental MOnitoring System) networks. Three REMOS networks have been installed in the areas of (a) the River Nestos deltaic channel, (b) Thesaurus dam-lake in the intramountainous valley and (c) Potamoi (Despat) and Pagoneri (Nestos) villages close to the borders between Hellas and Bulgaria. They record water level (H), water and air temperature (T), water conductivity (ECw), Redox potential (RP) and dissolved oxygen (DO) on a 24h basis, since the beginning of the year 2000. The research carried out in this paper, is focused on the REMOS station in the final course of Nestos in the deltaic area. The continuous monitoring and the data analysis yield useful results for the quality and quantity of the hydrologic regime of Nestos after the dams' construction, as well as for the trends detected of the quality parameters (ECw, RP and DO) and the water level, using the nonparametric Spearman's criterion. The best fitted model of time trend, for each variable, was chosen. The statistical sample of each one of the quality variables consisted of about 1000 values based on daily measures on a three years monitoring program (1/1/2000—31/12/2002). Further research and analysis for the other network stations of REMOS should provide useful results for the sustainable management of the transboundary River Nestos.     

Predicting the Fate and Transport of E. coli in Two Texas River Basins Using a Spatially Referenced Regression Model1

Abstract: The two main rivers of southeast Texas: Guadalupe and San Antonio have shown high temporal increase in bacteria concentration during the last decade. The SPAtially Referenced Regression On Watershed (SPARROW) attributes model, developed by the U.S. Geological Survey (USGS), has been applied to predict the fluxes and concentrations of contaminants in unmonitored streams and to identify the sources of these contaminants. This model identifies every reach as a basic network unit to distribute the sources, delivery, and attenuation factors. The model is data intensive and implements nonlinear regression to solve the parsimonious relations for describing various watershed processes. This study explored watershed and hydrological characteristics (land uses, precipitation, human and animal population, point sources, areal hydraulic load and drainage density, etc.) as the probable sources and delivery mechanisms of waterborne pathogens and their indicator (Escherichia coli [E. coli]) in the Guadalupe and San Antonio River basins. The effect of using various statistical indices for model selection on the final model’s ability to explain the various E. coli sources and transport processes was also analyzed.     

Duration and characteristics of metal price cycles

This paper addresses the fluctuations in real metal prices: are they simply random variations or do they display some degree of cyclicality? This study identifies peaks and troughs in the inflation adjusted prices for 14 metals, using monthly average data from January 1947 through December 2007. Duration dependence testing, which is performed on the expansions, contractions, and full cycles, finds many cases in which the duration of these phases are not purely random and have some degree of cyclicality. Additional characterization show that contractions generally persist longer than expansions (in contrast to macroeconomic cycles) that long-term real prices have been trendless, and that the amplitude of price changes over the phases has little regularity. For those performing this type of analysis, the appendices explain the procedures for dating turning points and assessing duration dependence.     

The microbial status of natural waters in a protected wilderness area

Waters derived from remote 'wilderness' locations have been assumed to be largely free of bacterial contamination and thus such, near-pristine, protected catchments, unused for agriculture, have been first in the multiple line of protection (pristine catchment-long storage-treatment-disinfection) employed by the water industry. This assumption is challenged by a bacterial survey of the waters derived from the New Cairngorm National Park, Scotland. Over 480 spot samples were taken for 59 sites between March 2001 and October 2002 during nine field campaigns each of three to five days duration. Over 75% of samples tested positive for Escherichia coli (E. coli) and 85% for total coliforms. Concentrations displayed both temporal and spatial patterns. Largest values occurred over the summer months and particularly at weekends at sites frequented by visitors, either for 'wild' camping or day visits, or where water was drawn from the river for drinking. Overall the spatial and temporal variations in bacterial concentrations suggest a relationship with visitor numbers and in particular wild camping. The implications of the results for drinking water quality and visitors health are discussed along with possible management options for the area in terms of improving the disposal of human waste.     

尾巨桉人工林小流域降水产流特征分析

研究尾巨桉(E.urophylla×E.grandis)生长阶段(林龄3.5—5.5 a)所处小流域的降水产流特征,有助于了解桉树生长过程的生态水文效应,对修订桉树人工林经营方案中注重提高生态系统的水源涵养能力有重要参考意义.以广西南宁桉树森林生态系统定位观测研究站(南宁桉树生态站)的闭合尾巨桉林小流域为试验区,在小流...     

水环境中大肠杆菌多特征抗原及抗体的制备研究

为了建立用于水环境中大肠杆菌的酶联免疫快速检测方法,针对水中大肠杆菌属多种血清型的特征,制备了水环境样品中大肠杆菌的多特征抗原,包括全菌体抗原、破碎全菌体抗原、菌体抗原、鞭毛抗原和菌毛抗原;采用这5种大肠杆菌抗原分别免疫新西兰大白兔,获得了5种大肠杆菌多克隆抗体,抗体效价高、纯度好,具有较强且稳定的特异性结合抗原的功能;间接ELISA方法表明,全菌体抗体和破碎全菌体抗体的效价均大于1×10⁵,性能优良.基于上述抗体,建立了水中大肠杆菌间接ELISA检测方法,实际水样的检测结果表明,检测限可达10⁴个/L.     

汽车工业中的功能安全研究

介绍了汽车工业中的电气/电子/可编程电子系统,分析了早期汽车生命周期过程、汽车开发和安全的集成过程以及汽车功能安全生命周期的组成,研究了从IEC61508功能安全转变为适用于汽车工业的安全标准的过程,阐述了汽车功能安全中的一些重要概念,给出了汽车功能安全分析的几种方法及其优缺点。     

Citizen funds and Dutch Disease in developing countries

Are Alaska-style citizen revenue distribution funds the solution to the resource curse in developing countries as their proponents conjecture? Unfortunately it appears not. First, it is questionable whether developing countries have the institutional capacity to implement and operate such funds successfully. Second, citizen funds are unlikely to have any substantial impact on governance and their macroeconomic effects are uncertain. Finally, as a comparative case study of the three natural resource-intensive economies that successfully steered clear of excessive real appreciation and crowding out of the non-minerals tradables sector—Botswana, Indonesia and Norway—shows, citizen funds are likely to carry detrimental indirect effects on the ability of governments to surmount the Dutch Disease.     

MBR中活性污泥对雌酮E1的吸附性能研究

研究了MBR中灭活污泥对雌酮(El)的吸附行为,考察了污泥浓度、污泥粒径和El初始浓度对E1吸附效果的影响,并探讨了不同污泥组分(悬浮颗粒、胶体和溶解物)对E1的吸附作用贡献.结果表明,在E1初始浓度为l～500μg·L-1,4h左右达到吸附平衡;E1的吸附符合Freundlich吸附模型,呈线性吸附;E1初始浓度越大,吸附速率越小.随着污泥浓度升高,单位污泥对E1的吸附量显著下降,出现了固体浓度效应;而吸附去除率却随着污泥浓度的升高而显著增加,且两者之间呈显著正相关(p＜0.05).活性污泥对E1的单位吸附容量随着污泥粒径增大而减小.污泥中悬浮颗粒、胶体和溶解物的含量分别为87.8％、9.6％和2.6％,吸附平衡时,E1在3种组分中的浓度分别为13.9 μg·g-1、24.1 g·g-1和12.5 μg· g-1,胶体吸附效果最好.不同组分对E1的吸附贡献与其含量正相关,吸附贡献为:悬浮颗粒＞胶体＞溶解物.