三种生产理论在北方荒漠化地区人地系统分析中的应用

本文运用可持续发展的“三种生产”理论，对我国北方荒漠化地区的人地系统进行了解析，指出人口生产的膨胀、物质生产的低效率和环境生产的萎缩，以及由此造成的三种生产系统之间支撑与制约机制的破坏，是导致我国北方荒漠化不断扩展的根本原因。     

An analysis of the environmental pressure exerted by the eucalyptus-based kraft pulp industry in Thailand

The study reported here focuses on the environmental pressure exerted by large-scale eucalyptus-based kraft pulp industry in Thailand. The objective of this study was to identify the most important sources of greenhouse gases, acidifying and eutrophying compounds and tropospheric ozone precursors, human toxicity compounds and solid waste associated with the kraft pulp industry. To this end, we performed an environmental systems analysis of the kraft pulp industry system in which we distinguished between two subsystems: the eucalyptus forestry subsystem and the kraft pulp production subsystem. The results indicate that the environmental pressure is caused by the kraft pulp production subsystem rather than by the eucalyptus forestry one. The chemical recovery unit was found to be the most important source of carbon dioxide (CO₂) and sulfur dioxide (SO₂) and responsible for more than one-half of the emissions of greenhouse gases and acidifying compounds from eucalyptus-based kraft pulp production in Thailand. Biomass combustion in the energy gene ration unit is an important source of nitrogen oxide (NO _x ) and carbon monoxide (CO) which in turn are responsible for over 50% of the emissions of tropospheric ozone precursors. About 73% of the eutrophication is caused by biological aerobic wastewater treatment emitting phosphorus (P). With respect to the eucalyptus forestry, only fertilizer use in eucalyptus plantations is a relevant source of pollution through the emission of nitrous oxide (N₂O) and phosphate (PO ₄ ³⁻ ).     

低湖平原典型湖垸水系规划数学模型——新兴垸排涝灌溉系统最优规划

以“四湖”地区典型湖垸（新兴垸）为背景，给出了典型湖垸水利系统满足综合设计排涝标准的评价准则。用大系统理论与方法，建立了该湖垸水利规划的大系统数学模型，提出了根据子系统之间的关联变量修建节制闸的设计思想，从而使排涝灌溉一体化。最后，用动态规划方法，给出了递推关系式。     

What can economic experiments tell us about institutional change in social–ecological systems?

Today, economic experiments are well accepted in mainstream economics. They are also widely applied in ecological economics, often focusing on institutions. Yet, many empirical studies in this field lack a sound theoretical foundation of institutions and institutional change. In this paper, I show that in a structure–agency framework three theoretical viewpoints on institutions can be distinguished. They can be viewed as (1) structures that shape incentives, (2) cognitive media, embedded in beliefs and cognition of agents, or (3) evolving from a process of agents’ choices and structural aspects. Using examples from the empirical experimental literature, I argue that all three viewpoints are mirrored in experimental practice, and that these can be organized into an institutional typology of economic experiments. Placing special emphasis on experiments with endogenous institutional choice and their relationship to evolutionary economic theory, I discuss under which conditions experiments are a useful method for the analysis of social–ecological systems, concluding that methodological and methodical innovations are an important prerequisite for challenging the dominant paradigm of neoclassical economics.     

Egg mimicry and allopaternal care: two mate-attracting tactics by which nesting striped darter (Etheostoma virgatum) males enhance reproductive success

In a variety of fish species with paternal care of offspring, females prefer to spawn in nests that already contain eggs. This female preference has been hypothesized to explain egg thievery in male sticklebacks, allopaternal care of eggs in minnows, and the evolution of egg-mimicking body features in male cichlids and darters. Here we employ microsatellite-based parentage analyses to evaluate the reproductive success of striped darter (Etheostoma virgatum) males that appear to utilize two of these functionally related tactics to entice females to spawn in their nests. In an isolated population (Clear Creek, Ky.), we observed that breeding males develop conspicuous white spots on their pectoral fins. If these spots are egg mimics, as we suspect, then this represents the fourth independent evolutionary origin of egg mimicry documented to date in darters, the first based on pigmentation (as opposed to physical structures), and the first in which the egg mimics vary greatly in number among males. From direct counts of microsatellite genotypes in clutches of embryos, at least 3.8 females contributed to the progeny within a typical nest, and females tended to spawn preferentially with males that were larger and displayed more egg-mimic spots. In another population (Hurricane Creek, Tenn.) without egg mimics, the multi-locus genetic data document that allopaternal care is common, especially among the smallest males who sometimes tend nests containing their own as well as an earlier sire's offspring. Thus, these foster males had adopted egg-containing nests and then successfully spawned with subsequent females. Overall, the genetic data on paternity and maternity, in conjunction with field observations, suggest that egg mimicry and allopaternal care are two mate-attracting reproductive tactics employed by striped darter males to exploit female preferences for spawning in nests with 'eggs'. Electronic Publication     

A new approach to quantitative assessment of reliability of passive systems

The objective of this paper is to show how probabilistic reliability can be assessed for complex systems in the absence of statistical data on their operating experience, based on performance evaluation of the dominant underlying physical processes. The approach is to distinguish between functional and performance probabilities when dealing with the quantification of the overall probability of a system to perform a given function in a given period of time (reliability). In the case of systems where sufficient statistical operating experience data are available, one can focus the quantitative evaluation entirely on the assessment of the functional probability for a given active item (e.g. a pump) by assuming that the specification, layout, construction and installation is such that the item is providing the assigned performance, e.g. in the form of generating the required flow rate. This is how traditional probabilistic safety assessments (PSAs) focus the reliability analysis for the various safety features on the calculation of values for the availability per demand. In contrast, for various systems relevant in advanced technical applications, such as passive safety features in innovative reactor designs, it is essential to evaluate both functional and performance probabilities explicitly and combine the two probabilities later on. This is of course due to the strong reliance of passive safety systems on inherent physical principles. In practice, this means that, for example, in case of a passive cooling system based on natural circulation of a given medium, one has to evaluate and to assess the probability to have a medium condition and a flow rate such that a cladding temperature, represented by a probability distribution, can be hold at a required level. A practical example of this method is given for the case of the reliability assessment of a residual passive heat removal system. General conclusions are drawn regarding reliability estimation of complex, interconnected systems in the absence of statistical performance data, such as for infrastructures.     

中国水资源管理适应气候变化的研究综述

以全球变暖为特征的气候变化已成为当今科学界、各国政府和社会公众普遍关注的最重要议题之一。气候变化对水资源管理的影响是具有重要学术价值的新兴研究方向,目前的重点研究领域主要包括:气候变化背景下水资源综合管理方式与集成研究,气候变化下水资源适应性管理机制,中国面临的水资源均衡性管理,公众参与水资源适应性管理的政策制定,对减缓措施与水资源可持续发展的认识。主要的研究方法包括:适应气候变化的定性分析方法(多尺度适应综合分析方法)、成本效益分析方法等。适应性管理是目前应对气候变化伴随的不确定性问题的有效策略,未来应在分析中国各流域水资源不确定性问题的基础上,建立气候变化情景下适应气候变化的水资源适应性管理体制机制。     

Optimal Design Methods for Hybrid Renewable Energy Systems

Renewable and hybrid energy systems (HESs) are expanding due to environmental concerns of climate change, air pollution, and depleting fossil fuels. Moreover, HESs can be cost effective in comparison with conventional power plants. This article reviews current methods for designing optimal HESs. The survey shows these systems are often developed on a medium scale in remote areas and stand-alone, but there is a global growing interest for larger scale deployments that are grid connected. Examples of HESs are PV–wind–battery and PV–diesel–battery. PV and wind energy sources are the most widely adopted. Diesel and batteries are often used but hydrogen is increasing as a clean energy carrier. The design of an efficient HES is challenging because HES models are nonlinear, non-convex, and composed of mixed-type variables that cannot be solved by traditional optimization methods. Alternatively, two types of approaches are typically used for designing optimal HESs: simulation-based optimization and metaheuristic optimization methods. Simulation-based optimization methods are limited in view of human intervention that makes them tedious, time consuming, and error prone. Metaheuristics are more efficient because they can handle automatically a range of complexities. In particular, multi-objective optimization (MOO) metaheuristics are the most appropriate for optimal HES because HES models involve multiple objectives at the same time such as cost, performance, supply/demand management, grid limitations, and so forth. This article shows that the energy research community has not fully utilized state-of-the-art MOO metaheuristics. More recent MOO metaheuristics could be used such as robust optimization and interactive optimization.     

流域水质目标管理的风险识别与对策研究

以水质目标为约束和核心的管理将逐步完善、补充和强化当前的总量控制模式,成为我国中长期流域水环境管理的重要内容.流域水质目标管理是一个"响应→调控"并不断反馈调整的过程,但由于流域系统的非线性和不确定性,流域污染减排并不能完全确保水质目标的实现.本文将这种由不确定性而引致的流域水质目标的不完全可达性界定为风险,并在分析流域水质目标管理框架思路的基础上,识别并实证了水质目标管理中的主要风险来源,主要包括:1在"响应"层面,由于水质响应与负荷削减等措施间的非线性、时滞性、指标不协同等不对应关系带来的风险;2在"调控"层面,由于水环境管理缺乏适应性的调控和反馈机制而产生的水质达标风险.在此基础上,提出了流域水质目标风险管理的转变途径及其定量表征方法,以期为流域水质目标风险管理提供借鉴.