Ecosystem network analysis indicators are generally robust to parameter uncertainty in a phosphorus model of Lake Sidney Lanier, USA

Understanding how data uncertainty influences ecosystem analysis is critical as we move toward ecosystem-based management. Here, we investigate how 18 Ecological Network Analysis (ENA) indicators that characterize ecosystem growth, development, and condition are affected by uncertainty in an ecosystem model of Lake Sidney Lanier (USA). We applied ENA to 122 plausible parameterizations of the ecosystem developed by Borrett and Osidele (2007, Ecological Modelling 200, 371-387), and then used the coefficient of variation (CV) to compare system indicator variability. We considered Total System Throughput (TST) as a measure of the underlying model uncertainty and tested three hypotheses. First, we hypothesized that non-ratio indicators whose calculation includes the TST would be at least as variable as TST if not more variable. Second, we postulated that indicators calculated as ratios, with TST in the numerator and denominator would tend to be less variable than TST because its influence will cancel. Last, we expected the Average Mutual Information (AMI) to be less variable than TST because it is a bounded function. Our work shows that the 18 indicators grouped into four categories. The first group has significantly larger CVs than the CV for TST. In this group, model uncertainty is amplified rendering these three indicators less useful. The second group of four indicators shows no significant difference in variability with respect to TST. Finally, there are two groups whose CV values are significantly lower than that for TST. The least variable group includes the ratio-based indicators and Average Mutual Information. Due to their low variability, we conclude that these indicators are the most robust to the parameter uncertainty and most useful for ecosystem assessment and comparative ecosystem analysis. In summary, this work suggests that we can be as certain, or more certain, in most of the selected ENA indicators as we are in the parameters of the model analyzed.     

煤自燃灾害气体指标的阶段特征试验研究

为分析煤自燃早期气体指标变化特征规律,更好地解决煤矿现场灭火救灾决策问题,通过煤自燃程序升温试验,首先得到煤样气氛中O2,CO,CO2,CH4,C2H4和C2H6气体的体积分数随温度的变化规律。根据煤体温度,将煤自燃前期划分为5个阶段(潜伏、储热、蒸发、活跃和乏氧)。分析3种不同变质程度的煤样的气体指标在各阶段的变化特征。建立煤自燃气体指标与特征温度阶段区间的对应关系。结果表明:在自燃潜伏阶段,煤的变质程度越低,早期越易产生CO,越难产生CH4;在储热阶段,煤的变质程度越低,早期越易且越快产生C2H6;在蒸发阶段,煤内外在水分脱附,低变质煤的C2H4也随之产生;在活跃阶段,各种气体体积分数均有剧烈增高的趋势,较高变质煤的C2H4也随之产生;在乏氧阶段,O2体积分数低于15%,与O2体积分数相关指标(CO/ΔO2,CO/CO2等)趋势有所改变。     

Reach‐Scale Geomorphic and Biological Effects of Localized Streambank Armoring

Armoring of streambanks is a common management response to perceived threats to adjacent infrastructure from flooding or erosion. Despite their pervasiveness, effects of reach‐scale bank armoring have received less attention than those of channelization or watershed‐scale hydromodification. In this study, we explored mechanistic ecosystem responses to armoring by comparing conditions upstream, within, and downstream of six stream reaches with bank armoring in Southern California. Assessments were based on four common stream‐channel assessment methods: (1) traditional geomorphic measures, (2) the California Rapid Assessment Method for wetlands, (3) bioassessment with benthic macroinvertebrates, and (4) bioassessment with stream algae. Although physical responses varied among stream types (mountain, transitional, and lowland), armored segments generally had lower slopes, more and deeper pools and fewer riffles, and increased sediment deposition. Several armored segments exhibited channel incision and bank toe failure. All classes of biological indicators showed subtle, mechanistic responses to physical changes. However, extreme heterogeneity among sites, the presence of catchment‐scale disturbances, and low sample size made it difficult to ascribe observed patterns solely to channel armoring. The data suggest that species‐level or functional group‐level metrics may be more sensitive tools than integrative indices of biotic integrity to local‐scale effects.     

Monitoring and environmental modeling of earthwork impacts: A road construction case study

This study presents the contributions of materials, earth engineering machines and construction techniques to potential environmental impacts from the main items of typical road earthworks. To achieve this goal, the overall activity at a 1.9-km long French earthworks project site for a heavily trafficked highway was surveyed during its 2007–2009 construction period. Using data collected and a numerical model of road life cycle assessment (LCA), i.e. ECORCE, six indicators could be evaluated, namely: energy consumption, global warming potential, acidification, eutrophication, photochemical ozone creation, and human chronic toxicity. When available, several life cycle inventories were implemented in order to appraise indicator sensitivity with respect to the considered panel of pollutants. Results also allowed estimating from an LCA point of view: (i) the conservation of both aggregates and soil as induced by quicklime treatment and (ii) the duration necessary for projected traffic levels to offset the potential environmental impacts of the earthworks stage.     

河南鸡冠洞洞穴水对极端气候的响应及其控制因素研究

为揭示洞穴水地球化学动态的变化特征及其控制因素,从2009年10月至2013年12月对黄土高原东南缘河南西部栾川县鸡冠洞洞穴水的水化学指标进行了4个完整水文年的动态监测.结果表明:1鸡冠洞洞穴水的化学类型主要是HCO-3-Ca2+-Mg2+和HCO-3-Mg2+-Ca2+型,阴离子中HCO-3占80%以上,阳离子中Ca2+、Mg2+是优势离子,地下河常年处于溶蚀状态,池水、滴水处于沉积状态.2鸡冠洞洞穴滴水、池水可以很好地响应外部气候环境的变化,其地球化学指标具有显著的季节效应.3Ca2+、Mg2+、SO2-4能够敏感地响应极端气候事件引起的年际降水量变化,Ca2+、Mg2+、SO2-4浓度洪涝年升高,干旱年降低.HCO-3主要受CO2浓度控制,对极端气候事件响应不明显.4鸡冠洞地下河中Ca2+、Mg2+、HCO-3、SO2-4浓度波动幅度较小,且无明显的季节变化规律.对2010年和2013年的极端降水事件响应不明显.     

Climate Change Impacts and Adaptation Strategies in Kenya

Abstract

To determine the climate changes that are due to natural variability and those due to human activities is quite challenging, just like delineating the impacts. Moreover, it is equally difficult to ascertain the adaptive strategies for coping with the climate changes and in particular for developing countries like Kenya. While climate change is a global phenomenon, the impacts are more or less specific to local areas such as observed in Kenyan case. Therefore climate change impacts adaptation strategies are appropriately applicable to a given local perspective. The study investigated the main indicators of climate change and effective adaptive strategies that can be employed in Kenya. Based on online questionnaire survey, the study established unpredictable rainfall patterns as the major indicator of climate change in the country, while water harvesting and change of cropping methods are the best adaptive strategies.     

The influence of the operational environment on the efficiency of water utilities

Adjusting for the operational environment in studies of performance measurement is very important, otherwise the analysis may lead to unrealistic scores, especially when its influence on costs is high, such as in the water utilities. In this paper, we study the influence of exogenous variables on the water utilities performance by applying conditional efficiency measures based on the order-m method and its probabilistic formulation. We use a sample of 66 water utilities operating between 2002 and 2008, representing about 70% of the Portuguese population. Our research suggests that inefficiency of Portuguese water utilities is substantial for some utilities: several exogenous variables might influence it considerably. For example, regulation has a positive influence on efficiency but when drinking water supply and wastewater services are provided by the same utility or when the wholesale and retail activities are provided together, the performance is lower. The effect of ownership is inconclusive and the variables residential customers, water source, peak factor, and density of customers have a mixed influence on performance which varies according to their scores.     

对改进我国生产安全事故统计工作的思考

做好生产安全事故统计工作,是国家制定相应的安全生产法规、政策和科学发展规划的重要依据,也是指导和加强安全生产管理、监督和监察工作的基础。本文简要回顾了我国生产安全事故统计工作发展情况;指出了当前事故统计工作中存在的问题;针对这些问题,作者就改进我国生产安全事故统计工作、进一步完善生产安全事故统计指标体系以及如何向国际劳工组织提供我国职业伤害统计数据等提出了自己的建议。     

中国与南非金属非金属矿山安全标准化标准比对分析及启示

近年来,我国矿难不断,人民生命财产受到了巨大的损失,而造成这些矿难的一个主要原因是矿山安全标准化工作存在疏漏。安全标准化的建设是夯实企业安全基础、强化企业安全管理、提升企业本质安全水平的强有力措施。通过分析我国与南非金属非金属矿山安全标准化标准的现状,从金属非金属矿山安全标准化的创建到围绕矿山安全标准化展开的14个核心要素,进行了全面的比对,并在比对的基础上,对其中存在较大差异的指标进行分析。总结了我国与南非矿山安全标准化之间的异同,指出了我国金属非金属矿山安全标准化标准存在的缺点和不足。基于具体技术指标比对分析以及对安全标准化缺点和不足的分析,对我国非煤矿山安全标准化发展提出参考意,借以希望为我国非煤矿山安全标准化标准的修订工作提供了一定的参考和帮助。     

噬菌体MS2作为水中肠道病毒指示生物的特征及其影响因素

噬菌体MS2作为潜在的水中肠道病毒指示生物,已逐渐成为回用水微生物学安全评价指标的主要研究方向之一。在此,阐述噬菌体MS2作为水中肠道病毒指示生物的主要特征,并介绍噬菌体MS2作为水中肠道病毒指示生物应用的影响因素。