The maximum power principle: An empirical investigation

The maximum power principle is a potential guide to understanding the patterns and processes of ecosystem development and sustainability. The principle predicts the selective persistence of ecosystem designs that capture a previously untapped energy source. This hypothesis was investigated empirically in controlled and replicated tests conducted in planktonic microcosms. Microecosystems that developed under a pH-controlled light regime, in which light duration was altered based on changes in an ecosystem-controllable variable (water column pH), were compared with those that developed under fixed photoperiods. According to the principle, pH-decreasing (and power-increasing) organization should selectively persist under pH-controlled light. To assess changes in pH dynamics that occurred under the alternative selection regime, in which photoperiods were not linked with pH-affecting selection or organization, the microecosystems that developed under fixed photoperiods were subjected to pH-controlled light on the last day of each test. The daily light duration increased 506 min on average in microecosystems that developed under pH-controlled light and 412 min on average in microecosystems that developed under fixed photoperiods. Selective reinforcement of acid-secreting blue-green algae in response to CO₂ and nutrient limitations could account for the greater increase in power acquisition in microecosystems that developed under pH-controlled light.     

Decision making in dune management: theory and practice

Effective decision making depends upon the availability of quality information. Procedures involved in assessing dune vulnerability and protection require monitoring of sporadic processes and information must be collected from many discipline sources. In particular, a significant challenge to strategic management is recognition of subtle discontinuities which could undermine the long term stability of the dune system. These changes may be irregular and/or non linear requiring managers to be aware of existing parameters, patterns and emerging discontinuities. A range of components within the system should be measured on a systematic, temporal and spatial basis. An environmentalchecklist is a useful management technique which systematises information, so that strategic objectives can be made operational and achievable. Problems can be identified and solved with this methodology particularly if it is incorporated into aW problem solving model. The checklist procedure proposed in this paper has been developed and tested in field conditions for a range of north-west and south-European dune systems. Whereas a universalchecklist applicable to all systems is utopian in aim, intra and extra-regional comparisons can be undertaken with only minor modifications of some components. Parameters covering site and dune morphology, beach condition; surface character of the seaward 200 m of the dunes; pressure of use and recent protection measures are the basis for calculating vulnerability and protection indices. The balance between these indices can be determined, analysed and form the foundation for future informed management decisions.     

Assessing the likelihood of secondary crashes on freeways with Adaptive Signal Control System deployed on alternate routes

Introduction: Reducing the likelihood of freeway secondary crashes will provide significant safety, operational and environmental benefits. This paper presents a method for assessing the likelihood of freeway secondary crashes with Adaptive Signal Control Systems (ASCS) deployed on alternate routes that are typically used by diverted freeway traffic to avoid any delay or congestion due to a freeway primary crash. Method: The method includes four steps: (1) identification of secondary crashes, (2) verification of alternate routes, (3) assessment of the likelihood of secondary crashes for freeways with ASCS deployed on alternate routes and non-ASCS (i.e. pre-timed, semi- or fully-actuated) alternate routes, and (4) investigation of unobserved heterogeneity of the likelihood of freeway secondary crashes. Four freeway sections (i.e., two with ASCS deployed on alternate routes and two non-ASCS alternate routes) in South Carolina are considered. Results and Conclusions: Findings from the logistic regression modeling reveal significant reduction in the likelihood of secondary crashes for one freeway section (i.e., Charleston I-26 E) with ASCS deployed on alternate route. Other factors such as rear-end crash, dark or limited light, peak period, and annual average daily traffic contribute to the likelihood of freeway secondary crashes. Furthermore, random-parameter logistic regression model results for Charleston I-26 E reveal that unobserved heterogeneity of ASCS effect exists across the observations and ASCS are associated with the reduction of the likelihood of freeway secondary crashes for 84% of the observations (i.e., primary crashes). Location of the primary crash on the freeway is observed to affect the benefit of ASCS toward freeway secondary crash reduction as the primary crash’s location determines how many upstream freeway vehicles will be able to take the alternate route. Practical Applications: Based on the findings, it is recommended that the South Carolina Department of Transportation (SCDOT) considers deploying ASCS on alternate routes parallel to freeway sections where high percentages of secondary crashes are found.     

基于前景理论和BWM的深基坑支护方案综合评价

针对深基坑施工工程的复杂性及决策者风险态度对多指标决策的影响,构建了融合前景理论的深基坑施工支护最优方案选择模型。首先建立深基坑支护方案优选决策问题的多目标评价指标体系,借鉴TOPSIS思想将正、负理想方案作为决策者参照值,在此基础上,进一步将灰色关联分析法引入前景理论定义了正、负价值函数;通过BWM方法得出各指标的客观权重,根据权重函数得到决策者对客观权重的主观评价,在此基础上计算每个备选方案的综合前景值并排序,获得最优支护方案。最终通过两个工程实例验证了模型的有效性,并通过与其他方法比较说明了该模型在准确性方面的优势。     

湘潭某新建小学安全现状及管理措施研究

为减少湘潭某新建小学校园安全事件的发生,本文采用安全检查表对该校进行安全隐患排查,通过排查发现该校存在一定的安全隐患问题,主要集中在“物的不安全状态”和“不良环境”2个方面,针对隐患依据4M理论从“人—机—环—管”4个方面提出合理可行的安全管理措施及隐患消除方法。经分析,该校校园环境中存在的安全隐患可通过采取科学有效的方法进行治理。希望本研究可以为小学校园安全管理提供一定的思路。     

相邻木结构建筑火灾蔓延临界值研究*

为研究相邻木结构建筑火灾由已燃建筑传递至未燃建筑的临界值,利用突变理论与数值模拟分别研究相同条件下贵州省典型木结构建筑火灾发展过程中发生突变现象的临界值,并采用实验手段对前2种方法所测得的结果进行验证,从而证明尖点突变理论在相邻木结构建筑火灾蔓延临界值预测中的可行性与有效性。建立描述相邻木结构建筑火灾发展过程的能量守恒方程,通过对能量守恒方程的推导,得到相邻木结构建筑火灾突变势函数。结果表明:在相邻木结构建筑火灾发展过程中,火焰由已燃建筑传递至未燃建筑这一过程具有尖点突变的特征,计算出的火灾蔓延临界值为892.2 K;根据数值模拟找到已燃建筑传递至未燃建筑的状态,此时的临界值为881.5 K:2组简易实验测得的临界温度分别为903.2,889.8 K,与突变理论预测值和数值模拟结果相比,3种方法误差不大,因此可认为利用尖点突变对相邻木结构建筑火灾突变临界值进行预测具有可行性。     

Who is susceptible and why? An agent-based approach to assessing vulnerability to drought

In this paper, we specify susceptibility to drought from a psychology-based bottom-up perspective. On the basis of the protection motivation theory (Rippetoe and Rogers in J Pers Soc Psychol 52(3):596–604, 1987), we developed the protection-capacity model (Krömker and Mosler in Global environmental change in Alpine regions: impact, recognition, adaptation, and mitigation. Edward Elgar, Cheltenham, pp 93–112, 2002) to analyse the susceptibility with respect to the protection capacity of agents. The protection capacity is determined by the agents’ subjective assessment of the situation, which consists of the appraisal of threat, on the one hand, and the coping appraisal, on the other hand. Additionally, the protection-capacity model specifies several factors which influence the two central appraisal processes. Empirical data were collected in interviews with experts and with a total of 65 exemplarily selected households which are typical for the respective case study regions (Andhra Pradesh, India; Algarve and Alentejo, Portugal; Volgograd and Saratov, Russia). The data were analysed with the help of fuzzy set methodology. Results show that the households of the Indian region are the most susceptible when compared to those of the Russian region with ‘low’ and to households of the Portuguese region with a ‘very low’ degree of susceptibility. Moreover, we identified subgroups within the regions which are characterized by different degrees of susceptibility and a different profile of factors influencing susceptibility. Altogether, the agent-based perspective allows identifying relevant factors that need to be addressed to minimize susceptibility of the population and special subgroups. However, the results are not representative for the case study regions because of the small database. Additionally, more effort is needed to validate the findings.     

木材工业粉尘污染与防治对策探讨

从宿迁市木材工业粉尘污染控制现状存在的问题入手,分析了木材工业企业粉尘污染的原因,提出了控制粉尘污染的若干建议。保护环境是实现木材工业可持续发展的必然要求,必须从工艺、技术和装备方面控制生产过程中的粉尘,使作业环境和大气污染排放达到国家环境保护标准和法规的要求。     

Indirect defense in a highly specific ant–plant mutualism

Although associations between myrmecophytes and their plant ants are recognized as a particularly effective form of protective mutualism, their functioning remains incompletely understood. This field study examined the ant-plant Hirtella physophora and its obligate ant associate Allomerus decemarticulatus. We formulated two hypotheses on the highly specific nature of this association: (1) Ant presence should be correlated with a marked reduction in the amount of herbivory on the plant foliage; (2) ant activity should be consistent with the "optimal defense" theory predicting that the most vulnerable and valuable parts of the plant are the best defended. We validated the first hypothesis by demonstrating that for ant-excluded plants, expanding leaves, but also newly matured ones in the long term, suffered significantly more herbivore damage than ant-inhabited plants. We showed that A. decemarticulatus workers represent both constitutive and inducible defenses for their host, by patrolling its foliage and rapidly recruiting nestmates to foliar wounds. On examining how these activities change according to the leaves’ developmental stage, we found that the number of patrolling ants dramatically decreased as the leaves matured, while leaf wounds induced ant recruitment regardless of the leaf’s age. The resulting level of these indirect defenses was roughly proportional to leaf vulnerability and value during its development, thus validating our second hypothesis predicting optimal protection. This led us to discuss the factors influencing ant activity on the plant’s surface. Our study emphasizes the importance of studying both the constitutive and inducible components of indirect defense when evaluating its efficacy and optimality.     

Synthesis and recommendations of the economic evaluation of OHS interventions at the company level conference

PROBLEM: In today's economic environment, enterprises may not be able to fund every new project aimed at promoting health and safety in the workplace. Company level economic evaluation of interventions can provide guidance in sound business decision-making. The Economic Evaluation of Occupational Health and Safety Interventions at the Company Level Meeting brought together members of the global occupational safety and health community interested in encouraging the use of economic knowledge and tools to evaluate economic gains from occupational health and safety interventions. DISCUSSION: Discussions of the six models presented explored similarities, reliability, and potential use by corporate enterprises, small and medium enterprises, developing and transitioning nations, and economic theorists. Each group provided specific projects that could be pursued to advance knowledge in the area of economic evaluation at the company level. CONCLUSION: This conference established pathway to incorporate economic evaluation of health and safety interventions or programs at the workplace.