Worker allocation in insect societies: coordination of nectar foragers and nectar receivers in honey bee (Apis mellifera) colonies

Nectar collection in the honey-bee is partitioned. Foragers collect nectar and take it to the nest, where they transfer it to receiver bees who then store it in cells. Because nectar is a fluctuating and unpredictable resource, changes in worker allocation are required to balance the work capacities of foragers and receivers so that the resource is exploited efficiently. Honey bee colonies use a complex system of signals and other feedback mechanisms to coordinate the relative and total work capacities of the two groups of workers involved. We present a functional evaluation of each of the component mechanisms used by honey bees – waggle dance, tremble dance, stop signal, shaking signal and abandonment – and analyse how their interplay leads to group-level regulation. We contrast the actual regulatory system of the honey bee with theory. The tremble dance conforms to predicted best use of information, where the group in excess applies negative feedback to itself and positive feedback to the group in shortage, but this is not true of the waggle dance. Reasons for this and other discrepancies are discussed. We also suggest reasons why honey bees use a combination of recruitment plus abandonment and not switching between subtasks, which is another mechanism for balancing the work capacities of foragers and receivers. We propose that the waggle and tremble dances are the primary regulation mechanisms, and that the stop and shaking signals are secondary mechanisms, which fine-tune the system. Fine-tuning is needed because of the inherent unreliability of the cues, queueing delays, which foragers use to make recruitment decisions. Received: 15 December 1998 / Received in revised form: 6 March 1999 / Accepted: 12 March 1999     

Bayesian estimation of European sulphur emissions using monitoring data and an acid deposition model

A statistical method for estimating national emissions of acidifying air pollutants in Europe is presented. The method uses an acid deposition model to match official emissions data from European countries and measured depositions from a monitoring network. An application to 1990 sulphate data demonstrates the method and suggests some tendencies in the reported emissions. The proposed framework may prove useful for verifying national compliance with emissions standards, and the method should be applicable also to other substances than sulphur dioxide. The problem of designing an optimal monitoring network may also be assessed within the proposed statistical framework.     

流域初始水权分配研究进展

当前我国水资源存在短缺和使用效率低下等问题,其最核心的解决办法就是建立水权市场,而其中的关键在于界定初始水权。通过界定初始水权,在各流域行政区域之间合理地分配。简要介绍了流域初始水权分配的最新研究进展和动态,主要包括分配原则、分配指标体系、分配方法和分配机制等方面。对这些研究进行了评述并且指出了存在的问题。由于水资源分配的特殊性,涉及到水量、水质和其它一些因素,单纯的分配水权难以获得成功。在此基础上,探讨了流域初始水权分配的未来研究方向,即在考虑到了水权、排污权和林权等集成的基础上,综合考虑初始水权分配的原则、指标体系和机制等,并且在分配方法上由单一目标模型向多目标模型发展,不确定性和模糊优化模型是未来流域水资源分配模型的发展方向。     

土地资源优化配置与土壤质量调控的系统动力学分析

土地资源优化配置及其环境效应已成为土地科学研究与保障国民经济持续健康发展的重要课题. 运用系统动力学方法,结合土壤质量调查评价,探讨江苏省无锡市区土地资源优化配置与土壤质量调控问题. 结果表明:经济社会发展目标与模式在很大程度上决定着土地资源配置格局,并进一步影响到区域生态环境条件和土壤质量;在经济发展优先模式下,无锡市区建设用地扩张迅速,环境负荷加重,粮食产量降低,2030年的综合土壤质量指数比2005年下降1.50;在生态保护优先模式下,无锡市区土地资源的人口承载压力趋缓,建设用地占用耕地现象得到有效控制,粮食产量较稳定,2030年的综合土壤质量指数仅比2005年下降0.57;未来土地资源配置格局应该以生态保护和提高土地资源配置的综合效益为调控重点.      

Available Water Supplies in Beijing,China, Under Single‐ and Multi‐Year Drought

Since its implementation in 2015, the Middle Route of the South‐to‐North Water Diversion Project (MR‐SNWDP) has transferred an average of 45 billion cubic meters of surface water per year from the Yangtze River in southern China to the Yellow River and Hai River Basin in northern China, but how that supply is able to cope with droughts under different scenarios has not been explored. In this study, using the water demand for 2020 as the guaranteed water target, a Water Evaluation and Planning system was used to simulate available water supplies in Beijing under different drought scenarios. In the case of a single‐year drought, without the MR‐SNWDP, Beijing’s water shortage ratio was 16.7%; with the MR‐SNWDP, this ratio reduced to 7.3%. In the case of a multi‐year drought, without the MR‐SNWDP, Beijing’s water shortage ratio was 25.3%; with the MR‐SNWDP, this ratio reduced to 7.4% and domestic water supply was improved. Our research suggests that to prepare for multi‐year drought in the Beijing area, the SNWDP supports increased supplies to the region that would mitigate drought effects. This study is, however, mostly focused on water supply provision to Beijing and does not comprehensively evaluate other potential impacts. Multiple additional avenues could be pursued that include replenishing groundwater, increasing reservoir storage, and water conservation methods. Further research is needed to explore the relative costs and benefits of these approaches.     

Urban road space allocation incorporating the safety and construction cost impacts of lane and footpath widths

Introduction: Walkability continues to attract great attention from urban planners, designers, and engineers as they recognize not only the merits of pedestrian facilities in terms of the health benefits but also their demerits in terms of accident risk to pedestrians. Wide footpaths improve the pedestrian environment and experience, and thereby motivate travelers to walk as much as possible. However, if footpaths are too wide, they may leave a smaller space for the roadway. On the other hand, wide road lanes may lead to higher road vehicle safety but are costly to construct and maintain and also may leave little space for the footpath. Evidently, for a fixed urban space, what is needed is an optimal balance between the vehicle lane and pedestrian path. This problem is encountered routinely in dense cities including Hong Kong where land availability is severely limited. Method: To address the issue, this paper first establishes safety performance functions (SPFs) for the pedestrian space and the road space, using the random-parameter negative binomial regression. The results indicate the extent to which road lane and footpath width changes are associated with changes in in-vehicle occupant and pedestrian casualties. Then the paper uses the SPFs to develop a methodology for optimizing the width allocations to the road lanes and footpaths, duly considering the user (safety) costs and agency (construction) costs associated with each candidate allocation of the widths. Finally, the paper analyzes the sensitivity of the optimal solution to the relative weights of user cost and agency cost. Results: When user and agency costs are considered equally important, the optimal lane width is 5.4 m. Conclusion: It is observed that the road space allocation ratio used by the Hong Kong road agency suggests that the agency places a higher weight to user cost compared to agency cost. Practical Application: The findings can help incorporate design-safety relationships, and the stakeholders (agency and users) perspectives in urban road and footpath design.     

基于环境基尼系数的控制单元水污染负荷分配优化研究

将基尼系数这一福利经济学概念引入松花江流域水污染物负荷分配过程,综合考虑水循环的社会-经济-资源-环境因素,从社会经济发展、科技进步水平、水污染治理水平和资源禀赋差异角度出发,遴选出人均GDP、重污染行业总产值比重、人均水污染物产生强度、工业水污染物去除率、生活水污染物去除率、单位国土面积水资源量、国控劣Ⅴ类断面占比7项指标,以COD及NH_3-N负荷为控制因子,辅以贡献系数这一表征外部不公平性参数,构建了以基尼系数为度量标准的流域水污染负荷优化分配模型,并据此制订了松花江流域33个控制单元基于公平性的水污染负荷分配方案。研究表明,2012年松花江流域基于7项指标的基尼系数值均大于0.4,超过了基尼系数合理警戒线,说明流域控制单元间COD及NH_3-N排放在社会经济和资源环境方面存在不公平现象,其中松花江干流和第二松花江流域是不公平性特征最为突出的两个流域。在Lingo模型优化分配得到的2020年流域各单元COD削减方案中,单元21的年削减量最大,为1.82万t/a,单元10的年均削减率最高,达8%;在相应NH_3-N削减方案中,单元21的年削减量及削减率均为最大,分别达到0.08万t/a及8%。     

试点碳市场配额有偿分配经验及对全国碳市场的借鉴意义分析

我国7省市碳排放权交易试点经过多年实践,积累了宝贵经验。在配额分配方面,多数试点在免费分配的基础上进行了配额有偿分配的探索,形成了各具特色的有偿分配实践。研究表明,试点碳市场配额有偿分配的经验对全国碳市场配额分配具有重要的参考借鉴意义。建议结合全国碳市场建设和发展实际以及配额分配实施方案的制定,科学合理设计有偿分配相关规则,并建立相应的监管机制。     

Evidence Supporting Cap and Trade as a Groundwater Policy Option for Reducing Irrigation Consumptive Use1

Thompson, Christopher L., Raymond J. Supalla, Derrel L. Martin, and Brian P. McMullen, 2009. Evidence Supporting Cap and Trade as a Groundwater Policy Option for Reducing Irrigation Consumptive Use. Journal of the American Water Resources Association (JAWRA) 45(6):1508‐1518. Abstract: In the American West water is becoming an increasingly scarce resource. Obligations to bordering states, endangered species protection, and long‐term resource sustainability objectives have created a need for most western states to reduce the consumption of irrigation water. In Nebraska specifically, the Nebraska Department of Natural Resources (NDNR) and local Natural Resource Districts (NRDs) are meeting a large part of this need by using a regulatory approach, commonly called groundwater allocation. The cost of allocation, which occurs in the form of reduced economic returns to irrigation, could be greatly reduced by using an integrated cap and trade approach. Much like environmental cap and trade programs which are used to reduce the cost of limiting environmental pollution, the trading of capped groundwater allocations can reduce the cost of limiting water use. In an analysis of a typical case in the Nebraska Republican Basin, we found that the impact of a water market to trade groundwater allocations depended on the size of the allocation and on the characteristics of the land and irrigation systems involved in the trade. Potential economic benefits from trade ranged from US$0 to US$120 per 1,000 cubic meters traded, from US$25 to US$250 per 1,000 cubic meters of reduction in consumptive use, and from US$16 to US$50 per hectare of irrigated land in the region. The highest benefits occurred at relatively high allocations, which capped withdrawals at 65‐75% of the expected unrestricted pumping level. These gains from trade would be split between buyers and sellers based on the negotiated selling price.     

温室气体排放配额初始分配的域外考察

从欧盟、英国和美国的立法实践来看,排放配额的初始分配在排放权交易计划实施的初期基本上以无偿分配为主、有偿分配为辅。从排放配额的财产权性质、温室气体排放活动的负外部性以及分配的公平和效率等方面来看,排放配额的初始分配应当采取有偿分配方式。