多环芳烃典型电子性质与其大型蚤光致毒性的构效关系研究

多环芳烃(PAHs)是环境中广泛分布的持久性有毒有机污染物,备受研究者关注。基于密度泛函理论(DFT)先期计算PAHs前线分子轨道能隙可能与其光致毒性诱发所需吸收光照辐射能有一致性,本研究选取非取代PAHs对大型蚤(Daphnia magna)光致毒性实验数据,通过DFT计算典型电子性质,由偏最小二乘(PLS)分析方法优化发展了定量构效关系模型,经与前人结果比较和验证其拟合优度、稳定性和内外部预测性能均有显著提升,可在应用域(AD)范围内准确预测PAHs光致毒性而满足风险评估需求。构效关系分析结果表明,PAHs光致毒性与分子前线轨道能隙紧密相关,除苯并[k]荧蒽和屈可能具有不同的光致毒性作用机制之外,多数PAHs若具有较低的前线轨道能隙、较小分子稳定性和较大分子变形性,均将有利于促进其光致毒性作用的发生;结合PAHs光致毒性与分子前线轨道能隙间的相关关系,可推测DFT计算前线轨道能隙宽度在2.740~4.208 e V之间和对应光照辐射波段约为295 nm~450 nm时,PAHs污染暴露将可能诱发较高的光致毒性效应。这为太阳光照射下PAHs光致毒性作用机制阐释和风险评价提供了数据支持与理论依据。     

Deconstruction of destruction stories: narrative,inequality, and disasters

A commonly‐held belief is that natural disasters do not discriminate. This paper, though, poses the following theoretical question: what does the elision of race, class, and gender in the news media say about disasters in the neoliberal era? It draws on the author's analysis of two prominent newspapers—The New York Times and USA Today—and their coverage of the recovery process after devastating tornadoes in two towns in the United States (Tuscaloosa, Alabama, and Joplin, Missouri) in 2011. The study asserts that the narrative of the news media is one with which people are familiar and that it fits into larger ‘formula stories’. It utilises theoretical treatments of narrative to demonstrate how differences are erased and how they lead to complicity in hegemonic representations. Critical theory is used to elucidate why this occurs, and the paper sources Goldberg (2002) in suggesting that the news media employs ‘fantasies of homogenisation’ when representing post‐disaster communities.     

Examining the agricultural producer identity: utilising the collective occupational identity construct to create a typology and profile of rural landholders in Victoria,Australia

Multifunctional rural landscapes are often characterised by contrasting values, land uses and land management practices of rural property owners. It seems these trends are, in part, an expression of rural landholder's identification as farmers. Existing typologies of rural landholders seldom take into account occupational identity. Research discussed in this paper addresses that gap. The objective was to apply the collective occupational identity construct to address the challenges of profiling rural landholders and test its effectiveness at distinguishing between different types of landholders. A 12-item scale was used to explore the extent rural landholders in south-eastern Australia held an agricultural producer identity. Cluster analysis resulted in the creation of four clusters of rural landholders with distinctive characteristics, suggesting the approach can provide researchers with a theoretically sound construct and practitioners with a useful tool as they attempt to better understand and engage rural landholders in sustainable agriculture.     

An inexact optimization approach for river water-quality management

A previously developed fuzzy waste load allocation model (FWLAM) for a river system is extended to address uncertainty involved in fixing the membership functions for the fuzzy goals of the pollution control agency (PCA) and the dischargers using the concept of grey systems. The model provides flexibility for the PCA and the dischargers to specify their goals independently, as the parameters for membership functions are considered as interval grey numbers instead of deterministic real numbers. An inexact or a grey fuzzy optimization model is developed in a multiobjective framework, to maximize the width of the interval valued fractional removal levels for providing latitude in decision-making and to minimize the width of the goal fulfillment level for reducing the system uncertainty. The concept of an acceptability index for order relation between two partially or fully overlapping intervals is used to get a deterministic equivalent of the grey fuzzy optimization model developed. The improvement of the optimal solutions over a previously developed grey fuzzy waste load allocation model (GFWLAM) is shown through an application to a hypothetical river system. The fuzzy multiobjective optimization and fuzzy goal programming techniques are used to solve the deterministic equivalent of the GFWLAM.     

Socially Strategic Ecological Restoration: A Game-Theoretic Analysis Shortened: Socially Strategic Restoration

Major transitions in a multiple-use or mosaic landscape often lead to frictions among new and existing users. In this article, we consider the problem of ecological restoration within a mosaic landscape in which restoration activities elicit feedbacks from individuals and groups that are harmed by restoration outcomes. Using game theory, we identify three potential outcomes ranked by the extent of restoration of ecosystem services and processes: nonstrategic, noncooperative strategic equilibrium, and cooperative bargaining solution. We identify conditions under which additional restoration can decrease the overall flow of ecosystem services and processes. A “strategic restorationist” will cease new restoration activities when the net effect of defensive response moves by farmers offsets gains. Imperfect information regarding expected payoffs to farmers can lead to inefficient overshooting or undershooting the optimal scale, geographical positioning, and form of restoration. Gains to all parties from cooperation might exist. As a case study and to aid model design, we consider restoration activities on California’s upper Sacramento River. An erratum to this article is available at .     

Towards a Formal Framework of Vulnerability to Climate Change

There is confusion regarding the notion of “vulnerability” in the climate change scientific community. Recent research has identified a need for formalisation, which would support accurate communication and the elimination of misunderstandings that result from the use of ambiguous terminology. Moreover, a formal framework of vulnerability is a prerequisite for computational approaches to its assessment. This paper presents an attempt at developing such a formal framework. We see vulnerability as a relative concept in the sense that accurate statements about vulnerability are possible only if one clearly specifies (1) the entity that is vulnerable, (2) the stimulus to which it is vulnerable and (3) the preference criteria to evaluate the outcome of the interaction between the entity and the stimulus. We relate the resulting framework to the Intergovernmental Panel on Climate Change conceptualisation of vulnerability and two recent vulnerability studies. This paper is dedicated to the memory of Gerhard Petschel-Held, whose pioneering work on syndromes of global change has been a source of inspiration for us and for others across various schools of thought on vulnerability.     

基于多元回归理论的太湖湖泛预警模型研究

在太湖宜兴段藻源性湖泛高发区设立4个监测点,以湖泛发生的物质基础"藻类生物量"为研究对象,运用数据分析软件SPSS对监测点的藻类生物量、水质、气温等数据进行相关分析,建立了以藻密度为因变量的多元逐步回归模型。结合往年太湖藻源性湖泛发生时的气象条件等历史资料以及相关藻密度阈值的报道,构建了太湖宜兴段藻源性湖泛高发区监测预警模型系统,该模型能够基于监测点的实时水质数据和气象预报数据,对监控区域湖水在未来某时间段内发生湖泛风险的可能性进行分级预警。     

Epidemiological risk assessment using linked network and grid based modelling: Phytophthora ramorum and Phytophthora kernoviae in the UK

We developed a stochastic simulation model incorporating most processes likely to be important in the spread of Phytophthora ramorum and similar diseases across the British landscape (covering Rhododendron ponticum in woodland and nurseries, and Vaccinium myrtillus in heathland). The simulation allows for movements of diseased plants within a realistically modelled trade network and long-distance natural dispersal. A series of simulation experiments were run with the model, representing an experiment varying the epidemic pressure and linkage between natural vegetation and horticultural trade, with or without disease spread in commercial trade, and with or without inspections-with-eradication, to give a 2 × 2 × 2 × 2 factorial started at 10 arbitrary locations spread across England. Fifty replicate simulations were made at each set of parameter values. Individual epidemics varied dramatically in size due to stochastic effects throughout the model. Across a range of epidemic pressures, the size of the epidemic was 5–13 times larger when commercial movement of plants was included. A key unknown factor in the system is the area of susceptible habitat outside the nursery system. Inspections, with a probability of detection and efficiency of infected-plant removal of 80% and made at 90-day intervals, reduced the size of epidemics by about 60% across the three sectors with a density of 1% susceptible plants in broadleaf woodland and heathland. Reducing this density to 0.1% largely isolated the trade network, so that inspections reduced the final epidemic size by over 90%, and most epidemics ended without escape into nature. Even in this case, however, major wild epidemics developed in a few percent of cases. Provided the number of new introductions remains low, the current inspection policy will control most epidemics. However, as the rate of introduction increases, it can overwhelm any reasonable inspection regime, largely due to spread prior to detection.     

1,3-丁二烯与DNA交联机理的研究——代谢产物在DNA大沟股间交联反应的AM1计算

采用ＡＭ１方法计算了环境致癌物１,３－丁二烯（ＢＤ）的代谢产物１,２－环氧－３,４－丁烯（ＥＢ）和１,２,３,４－二环氧丁烷（ＤＥＢ）与ＤＮＡ腺嘌呤和胞嘧啶烷化反应过程速率控制步骤的活化能,以及ＤＥＢ在ＤＮＡ大沟侧与不同序列ＤＮＡ片断生成烷化股间横向交联产物的结构和能量．结论认为：用烷化反应的难易程度难以解释ＤＥＢ的致突性比ＥＢ约大１００倍的实验事实;强致突的ＤＥＢ可与碱基发生２次烷化反应,生成ＤＮＡ交联产物;而ＥＢ则不能交联,这可能为２者基因毒性差异巨大的分子机制;同时ＤＥＢ在ＤＮＡ大沟侧可与多种不同的ＤＮＡ序列发生股间横向交联,对比在小沟侧只与２种序列交联,此发生股间横交联几率的差异合理地解释了ＤＥＢ致突的碱基选择性     

国土资源规制:基本理论与中国实践

规制是政府或其特定部门,对企业及家庭、组织等行为,依据特定规定进行特定的约束.该文基于国土资源基础及其稀缺性和公共物品属性,以及企业活动的资源环境外部性等理论,提出国土资源规制的概念,认为国土资源规制既是对与国土资源相关的行为的规制,也是以国土资源为手段对企业及地方政府的规制.国土资源规制的基本内容包括:明晰国土资源基础状况、编制区域国土功能区划和国土规划、确定关键性国土资源的开发利用标准;优化国土资源规制路径,强化经济、法律、技术手段在国土资源规制中的运用;评定国土资源规制效果等.中国国土资源规制主要体现在土地参与宏观调控、用水配额管理和制定能源效率标准等方面.依据中国国土资源规制实践,选择出8个包含土地、水、能源、矿产和森林等在内的国土资源规制指标,以期建构我国国土资源规制的基本指标体系.同时,建议加强对重点行业和重点地区的国土资源规制,调整并完善现行统计指标体系和干部考核体系,以适应国土资源规制的需要.