Developing indicators for assessing land-use sustainability in a tropical agro-ecosystem: The case of Sakaekrang watershed,Thailand

While the concept of sustainable land management is now widely accepted, there remains considerable scope for developing location-specific land-use indicators for sustainability evaluation. A study was conducted to investigate the indicators of land-use sustainability in the context of tropical agro-ecosystems using the case of Sakaekrang watershed, Thailand. The biophysical data were generated from Geographic Information Systems (GIs) and the socioeconomic data were collected through a field survey. In the light of sustainable land management objectives, a total of 32 criteria were considered in the analysis to determine land-use sustainability and identify indicators that best explain the sustainability level. About one quarter of the agricultural area in the watershed meets the sustainability threshold, indicating a substantial unstable area in the watershed. Among 11 indicators that showed a significant relationship with the computed land-use sustainability, land quality, source of farm income, and evapo transpiration were the most important.     

臭氧接触池臭氧投加方式的优化

臭氧接触池内臭氧(O₃)投加方式是影响臭氧接触池反应效率的关键因素. 以密云水库水为处理对象,对臭氧接触池内臭氧投加方式进行优化,通过考察气液接触方式和投加点个数对ρ(O₃)、传质效率及有机物去除率的影响,确定最优臭氧投加方式. 结果表明,适当增加布气点个数可有效增强气液传质,提高有机物去除率,但当布气点个数高于3个时,臭氧传质效率无明显提升,而且造成出水ρ(O₃)过高,不利于后续工艺的进行. 采用三段式臭氧投加方式,臭氧投加比为3∶3∶1时,密云水库水中臭氧传质效率达78.1%,有机物去除率为47.5%; 向密云水库水中添加3mg/L腐殖酸后,该投加比下臭氧传质效率为76.8%,有机物去除率为40.3%,出水ρ(O₃)为0.26mg/L,不会对后续工艺产生影响;并且该条件下臭氧利用率最高,BrO₃-生成量最低,为最佳臭氧投加比.      

Interactions between scientific uncertainty and flood management decisions: Two case studies in Colorado

Flood management policies in the United States rely on scientific information about the frequency and intensity of extreme precipitation and runoff. Yet, the available information is inherently uncertain because of the complexity of meteorological and hydrological processes. In mountainous areas, flood risk can vary greatly even within short distances depending on local climate, topography, soil characteristics, and land use. This paper describes two Colorado cases in which policy makers were presented with conflicting scientific estimates: revision of the Fort Collins floodplain map and modification of the Cherry Creek Dam. The case studies demonstrate that uncertainty can have substantial impacts on regulatory processes, public safety, and costs. The analysis considers the differing perspectives of various participants in the flood management processes, illustrating the interplay between uncertainties attributable to scientific issues and values issues. It suggests that attempts to provide a single “best” estimate do not necessarily meet the decision needs of all stakeholders. Conclusions indicate a need to improve communication about uncertainty when scientific estimates areprovided to decision makers. Furthermore, in highly controversial decisions, it may be necessary to reframe the discussion to consider the values issues raised by scientific uncertainty.     

Maternal transfer of mercury to the developing embryo/fetus: is there a safe level?

Mercury (Hg) exposure is ubiquitous in modern society via vaccines, fish/crustacea, dental amalgam, food, water, and the atmosphere. This article examines Hg exposure in the context of primary exposure to pregnant women and secondary exposure experienced by their unborn babies. Babies in utero are particularly at risk of higher Hg exposure than adults (on a dose/weight basis through maternal Hg transfer via the placenta), and are more susceptible to adverse effects from mercury and its biologically active compounds. It is, therefore, critical that regulatory advisories around maximum safe Hg exposures account for pregnant women and secondary exposure that children in utero experience. This study focused on standardized embryonic and fetal Hg exposures via primary exposure to the pregnant mother of two common Hg sources (dietary fish and parenteral vaccines). Data demonstrated that Hg exposures, particularly during the first trimester of pregnancy, at well-established dose/weight ratios produced severe damage to humans including death. In light of research suggestive of a mercuric risk factor for childhood conditions such as tic disorders, cerebral palsy, and autism, it is essential that Hg advisories account for secondary prenatal human exposures.     

油菜菌核病菌(Sclerotinia sclerotiorum)与细菌间的基因水平转移

油菜菌核病（Sclerotinia sclerotiorum）是油菜生产上最重要的病害之一,其致病性可能来源于基因水平转移（Horizontal gene transfer,HGT）.为认识其致病原理和寻找新的真菌抑制剂的靶点,首先通过BLASTp发现其基因XM₀01585458.1编码蛋白XP₀01585508.1与细菌比对结果中出现低E值3.23e-109和高SCORE值436,暗示存在HGT现象;进一步通过系统进化树的建立,发现该蛋白在进化分枝上更接近于细菌中由Streptomyces sp.C的NZ_CM000832.1基因编码的蛋白ZP₀7291173;同时核苷酸组成分析也发现该基因与油菜菌核病菌基因组的碱基组成有较大差别,GC含量提高了14.95%.这些结果证明了XM₀01585458.1的确存在基因水平转移事件.结构分析和COG蛋白功能分类显示该HGT序列编码蛋白XP₀01585508.1具有FA58C₃（Coagulation factors 5/8 type C domain）、Kelch repeat type 1、Galactose-binding domain-like、Galactose oxidase/kelch,beta-propeller等保守结构域,应为一个膜蛋白并参与多糖代谢,推测该水平转移基因与S.sclerotiorum在侵染植物时进行细胞壁水解和致病性有关.     

Computer modeling of genome complexity variation trends in prokaryotic communities under varying habitat conditions

There are two types of organisms’ grouping in nature: mono-species populations and multi-species communities. Here at during the process of evolution the adaptability of a trait is to be tested both at population and ecocenotic levels. Size of a genome is one of the major adaptive traits, which widely varies in eukaryotic species. By contrast, prokaryotes with their small genomes are considered to have genome reduction evolutionary trend. Domination of this trend is mostly founded on population-level models. In this paper we in silico study interactions of ecocenotic and population levels. The trend of genome and metabolism reduction in prokaryotic communities was shown to be major only in comfortable environmental conditions. In subcomfortable conditions, genome and metabolism reduction leads to community simplification (in extreme case to community death). Pessimum conditions promote metabolism integration of a community and induce reciprocal genes acquiring.     

遥感与GIS在蝗虫生境研究中的应用进展

蝗虫生境是蝗虫赖以生活、生存的环境。利用遥感技术获取与蝗虫密切相关的各种生境因子,并结合GIS技术研究和阐明蝗虫的生境因子对东亚飞蝗的产卵、孵化、成虫、迁飞等生育周期的影响机理,是实现对蝗虫监测、预测预警的基础。文章首先分析了各种蝗虫生境因子对蝗虫发生的影响机理,认为这些生境因子对蝗灾发生的影响不是孤立地起作用的,仅靠单个生境因子进行蝗灾的预测是不全面的,而遥感和GIS技术方便的获取、管理和分析多种生境因子数据,在大尺度蝗灾发生监测和预警中起到不可替代的作用。通过对遥感与GIS在蝗虫的不同发育阶段（蝗卵发育阶段、蝗蝻发育阶段和成虫阶段）的应用及其进展的分析,认为对蝗虫不同生育阶段的遥感监测需采用不同的参数和技术才能达到更好的效果,最后提出了遥感与GIS在蝗虫生境监测方面的未来发展方向。     

基于ArcGIS Engine设计天然气管道泄漏事故后果评估系统

城市天然气管道是城市不可缺少的基础设施之一,为有效遏制天然气管道事故造成的重大灾害,需加强对应急救援系统的研究。选取高斯模型分析泄漏的天然气的扩散过程,并划分事故后果评估区域。利用ArcGIS Engine平台,设计并建立一个城市天然气管道泄漏事故的应急救援系统。利用该系统可模拟天然气管道泄漏后可能发生的气体扩散、火灾、爆炸等事故后果,通过天然气理化参数、天然气泄漏的初始状态和周围环境的气象条件,以可视化方式直观显示不同等级的事故后果评估缓冲区。     

驾驶行为模型的研究进展

驾驶员行为模型的研究对于预测和干预驾驶员的风险行为、设计相关的道路安全设施与车内设备,以及制定交通法律法规等具有重要的意义。为了解和掌握学术界关于驾驶行为模型的研究进展,搜集、筛选和归纳了1960—2010年被SCI数据库索引的相关文章,将驾驶行为模型分类为描述性模型、信息处理模型、动机模型、计划行为理论(TPB)和躯体标识假设,并对每种模型进行评述和总结,理清这些模型间的内在联系。研究发现,现有各模型只是从某个角度研究驾驶员行为的部分特征,而不能解释驾驶员的全部行为。今后应不断完善和整合各类模型,并借鉴心理学、生理学和行为科学等相关领域的理论、知识,使驾驶行为模型变得更为实用、有效。     

校园突发事件中大学生信息传播行为偏好研究

在校园突发事件中,大学生作为直接受影响方,既是危机信息的接受者,又是其传播者。大学生在突发事件情景下的信息传播行为受多方面因素影响,通过对上海、北京、广州等城市9所高等院校的303名在校大学生的问卷调查,利用离散选择模型识别影响大学生危机信息传播行为的主要因素,并预测其在传播决策、信息内容、传播对象和传播渠道上的选择概率。研究结果表明,一旦校园突发事件发生,大学生对外进行信息传播的行为是不可避免的,校方对突发事件信息的披露程度和对危机的处置措施将影响其信息传播的内容和渠道偏好。