Eco(nomics/logy)

This note discusses the analytic tools available for studying the interrelations between the economy and the ecological system. It points out the importance of the concept of cooperative games as an addition to the emphasis on non-cooperative games in both economics and ecology. The relation between both concepts of the games and the market system is discussed.     

A condition for cooperation in a game on complex networks

We study a condition of favoring cooperation in Prisoner's Dilemma game on complex networks. There are two kinds of players: cooperators and defectors. Cooperators pay a benefit b to their neighbors at a cost c, whereas defectors only receive a benefit. The game is a death-birth process with weak selection. Although it has been widely thought that b/c>〈k〉 is a condition of favoring cooperation (Ohtsuki et al., 2006), we find that b/c>〈k_nn〉 is the condition. We also show that among three representative networks, namely, regular, random, and scale-free, a regular network favors cooperation the most, whereas a scale-free network favors cooperation the least. In an ideal scale-free network, cooperation is never realized. Whether or not the scale-free network and network heterogeneity favor cooperation depends on the details of the game, although it is occasionally believed that these favor cooperation irrespective of the game structure.     

冬奥会对举办城市生态环境的影响研究进展

冬季奥林匹克运动会被认为是促进举办城市可持续发展转型升级的催化剂,但在给举办城市带来经济、社会、文化、环境进一步发展的同时,也将带来各种不利影响和风险。关于冬奥会影响的学术研究早期主要集中在经济、社会和文化方面,近年来才转向对城市结构和功能、生态系统保护、环境保护、可持续发展和遗产管理等影响的研究。但国内外学术界关于冬奥会给举办城市、环境及其可持续发展造成影响的研究仍比较匮乏。通过对历届冬奥会对主办城市的生态环境及可持续发展的影响以及环境保护的关注度进行综述,分析冬奥会生态环境影响研究方面的主要进展,并提出未来生态环境保护方面需要关注的重点研究领域和问题,包括开展冬奥会全生命周期环境影响评价,关注和实施全过程环境风险管理,加强冬奥会环境和可持续发展监测和评估,构建冬奥会环境制度体系、可持续共治机制,以期为我国举办2022冬奥会提供经验参考。     

Modeling reciprocation and cooperation in primates: evidence for a punishing strategy

Experiments in which animals strategically interact with one another or search over some controlled domain are becoming common. While these experiments often promise to illuminate sophisticated animal behavior, the analyses brought to bear on these data are often quite coarse. For example, many papers simply tally the number of observations consistent with a behavioral theory. This analysis is simple, but ignores a potentially rich source of information by failing to take into account patterns and systematic variation among observations inconsistent with the theory. Using a new data set generated by cotton-top tamarin monkeys playing a repeated food-exchange game, we apply a maximum-likelihood estimation technique (more commonly used to study human economic behavior) which utilizes much more of the information in these data, and which uncovers unexpectedly sophisticated cooperative behavior from our subjects. Tamarin cooperation remains stable as long as both actors consistently cooperate, but requires at least two consecutive unexpected acts of cooperation to restart cooperation after it has collapsed, a strategy that resembles two-tits for a tat. We conclude by enumerating the benefits of a maximum-likelihood approach in experimental settings such as ours, and suggest other areas in which these techniques may be fruitful.     

A game to teach the life cycles of fungi

Three difficulties encountered by students studying the life cycles of fungi are discussed: (a) Correlating photomicrographs, which sometimes include artefacts, with schematic drawings; (b) Correlating the life cycles of parasitic fungi with those of their hosts and the symptoms of fungal disease; (c) Understanding the cyclic development of fungi, which may have alternating micro- and macro-cycles. A game, developed to help students to overcome these difficulties, is described. Pictures of fungi, as seen by students through microscopes and in their textbooks, have to be correlated in the game with drawings of the fungi. An identification sheet allows students to check their results. Students then have to place cards, on which there are drawings of the different stages in the development of various fungi and their hosts, on a board, so that the parallel stages of host and parasite are next to each other and the photomicrograph drawings form a cycle. In the case of rusts, two cycles have to be produced, and two hosts have to be positioned correctly in the cycles. The game also provides cards to mark seasons and a solution sheet for self-evaluation.     

A 7 year pollen profile of major Olympic Games venues in Sydney, Australia

The year 2000 Olympic and Paralympic Games heldin Sydney, Australia were unique in the historyof the Games because they were staged in theearly to mid spring. This led to the concernthat pollen-sensitive athletes may havesignificant problems with allergic symptomstriggered by pollen exposure and that this mayhave compromised their ability to attain theirbest performance. Unfortunately, there was nosystematic pollen count data available for thecity of Sydney up until this time so thepurpose of this study was to obtain a profileof the pattern and type of pollens in theregion so that Olympic team managers andmedical staff could be adequately advised andable to prepare allergic athletes for anyexposures encountered while training andcompeting.We performed pollen monitoring of three majorOlympic venues over the six years before theGames to provide a profile of the mostprevalent species appearing over the spring.The pollen counts obtained at the major siteswere extremely high over the periods oftraining and competition. Tree pollens appearedfrom late July, peaking in August andSeptember, whilst grass pollens appeared fromSeptember and peaked in mid October. Arelatively small number of pollen varietiescomprise the majority of the pollen count.     

Drug testing data from the 2007 Pan American Games: δ C values of urinary androsterone, etiocholanolone and androstanediols determined by GC/C/IRMS

The main purpose of this article is to show the application of the CG/C/IRMS in real time during competition in the steroid confirmation analysis. For this reason, this paper summarizes the results obtained from the doping control analysis during the period of the 2007 Pan American Games held in Rio de Janeiro, Brazil. Approximately 5600 athletes from 42 different countries competed in the games. Testing was performed in accordance to World Anti-Doping Agency (WADA) technical note for prohibited substances. This paper reports data where abnormal urinary steroid profiles, have been found with the screening procedures. One 8 mL urine sample was used for the analysis of five steroid metabolites with two separate analyses by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). Urine samples were submitted to GC/C/IRMS for confirmation analysis to determine the ¹³C/¹²C ratio of selected steroids. Fifty-seven urine samples were analyzed by GC/C/IRMS and the δ ¹³C values (‰) of androsterone, etiocholanolone, 5β-androstane-3α, 17β-diol (5β-diol), 5α-androstane-3α, 17β-diol (5α-diol) and 5β-pregnane-3α, 20α-diol (5β-pdiol), the endogenous reference compound are presented. One urine sample with a testosterone/epitestosterone (T/E) ratio of 4.7 was confirmed to be positive of doping by GC/C/IRMS analysis. The δ values of 5β-diol and 5α-diol were 3.8 and 10.8, respectively, compared to the endogenous reference compound 5β-pdiol, which exceeded the WADA limit of 3‰. The results obtained by CG/C/IRMS confirmation analyses, in suspicious samples, were conclusive in deciding whether or not a doping steroid violation had occurred.     

奥运期间北京PM2.5、NOX、CO的动态特征及影响因素

为了成功举办第29届奥运会,确保北京奥运期间空气质量良好,采取交通管制和工厂停工等临时减排措施改善北京空气环境,希望通过这些措施使大气污染物排放量大幅度降低。在奥运前的综合治理措施中,已经对北京市的烟尘和粉尘排放控制起到了明显效果。在奥运期间更是执行了严格的燃煤污染控制和工业污染控制措施。奥运期间19家重点排污企业和4家燃煤电厂,采取压缩产量、调整运行方式、加强污染设施运行管理等措施,在确保达标基础上,减排30%。并从2008年7月1日起执行世界上最严格的燃煤锅炉排放标准限值。为控制工业污染,150多家重污染企业停产减产限产。这些举措使得奥运期间烟尘和粉尘的排放量大大减少,对PM2.5、NOX、CO的浓度下降起重要作用。此外,奥运期间城区工地停止土石方工程和混凝土浇注工程,对减少施工扬尘、建筑扬尘有明显效果。机关单位、商场、居民实行了错峰上下班措施和公交出行等绿色出行方式,进一步减少了PM2.5、NOX、CO的来源和积累。利用北京城市系统生态研究站的空气环境质量监测数据,对奥运期间北京可吸入颗粒物(PM2.5)、氮氧化物(NOX)、一氧化碳(CO)的日平均浓度的动态特征及其气象因素的关系进行了分析。结果表明:北京奥运期间PM2.5、NOX、CO在生态中心观测点与教学植物园观测点的平均浓度分别为0.060和0.070、0.065mg/m3和0.03、0.65和1.10mg/m3,显著低于奥运后PM2.5、NOX、CO日平均浓度。奥运后PM2.5日平均浓度与奥运期间比较,生态中心站与教学植物园站分别升高3.3%与58.8%,NOX日平均浓度与奥运期间比较2个站分别升高76.9%和56.7%,CO日平均浓度与奥运期间比较2个站分别升高56.5%和163%。奥运期间PM2.5、NOX、CO质量浓度的日变化都呈双峰现象,一个峰出现在7:00—10:00之间,另一个峰出现在18:00—23:00之间,这一特征与通常的北京空气污染物日变化过程一致,污染物浓度日变化双峰现象,虽与气象条件有关,但汽车尾气排放也是一个重要影响因素。主要是由于上班、上学、交通运输的高峰期,车流量大,尾气排放量也大,从而可能对形成上午与夜间的两个PM2.5、NOX、CO浓度高峰起了重要作用。奥运期间污染物除了生态中心监测点的PM2.5小时平均浓度与小时平均温度、风速有显著相关性,与其他气象因素并无相关性。研究表明奥运期间实施的临时空气环境污染控制措施有明显的效果。     

Evolution,games theory and polyhedra

The problem of finding an Evolutionary Stable Strategy (ESS) for an animal species is defined. It is shown how such strategies are a subset of the equilibrium solutions for a particular non-zero sum game. These equilibrium solutions are then shown to arise from the vertices of a particular convex polyhedron. A method of finding these equilibrium solutions through the vertices and then the ESS solutions is given. This is illustrated by a number of numerical examples taken from the literature. Finally an alternative approach based on solving a Linear Complementarity Problem is discussed.