关键词： 阶段结构   Mawhin延拓定理   正周期解   自反馈   生态经济  

摘要： 研究了一类具有阶段结构与延迟自反馈的生态经济模型,利用重合度理论的Mawhin延拓定理,给出了使得生态经济模型正周期解存在的充分性条件,推广了已有的相关结果.

关键词： Diabetes mellitus   Economic modelling   Review  

摘要： Objective: To identify and critically appraise cost-effectiveness models developed to evaluate type 2 diabetes (T2D) treatments and to assess which types of treatment effects they capture. Research design and methods: A systematic search was performed in MEDLINE, EMBASE, Centre for Reviews and Dissemination databases at the University of York, and Health Economic Evaluation Database for the period to September 2008. The websites of Health Technology Assessment (HTA) bodies in different countries were also screened for relevant models. For each of the identified original models, details of the structure, data in-and outputs were extracted and the overall quality of the model in terms of the combination of structure, assumptions and data inputs were appraised using published criteria. Results: Seventy-eight articles and 41 HTAs reporting relevant economic evaluations were identified. There were ten models with multiple publications, and a further ten models with one associated publication. The critical review demonstrated that most had the same fundamental structure, used similar micro-simulation techniques and were based on the same key data sources. However, the process for identification of relevant data and their synthesis, and the selection of outcomes lacked transparency. The models differed according to the extent and type of interventions they evaluated and which diabetes complications and treatment-related adverse events were captured. For example, just one model incorporated changes in patient weight, despite the fact that weight gain can be a side-effect of some treatments, and weight loss a potential benefit of others. Conclusions: Whilst many economic models exist in T2D, most share common features such as the model type. Identified shortcomings are lack of transparency in data identification and evidence synthesis as well as the selection of the modelled outcomes. Future models should aim to include all relevant treatment outcomes, whether these relate t

关键词： RELIGION   WOMEN & religion   SOCIAL institutions   ENTREPRENEURSHIP  

摘要： According to the religious economies model, religious supply in open religious economies should adapt to the demands of diverse market niches. This proposition is inconsistent with the finding that, although women constitute the majority of religious consumers, the majority of the religions produced in the American religious marketplace favor men's interests relative to women's. Three modifications to the religious economies model are suggested to account for this contradiction. The first modification is a respecification of "religious capital" that takes into account unequal distributions of power among producers of religious value and their differential effects on the beneficiaries and targets of religious norms. The second modification theorizes religion's linkages to other social institutions as sources of cost and benefit that are taken into account by religious entrepreneurs. The third modification accounts for status-based discrimination and unequal distributions of capital as sources of constraint that influence the production of religious supply. Several directions for future research are proposed.

摘要： This paper describes Gary Becker's theoretical models of marriage. At the micro level, these are all rational choice models. At the market level, Becker offers two major types of models: partial equilibrium models based on price theory as taught by Marshall and Friedman;and optimal sorting models based on optimal assignment models. This paper examines some of the possible intellectual influences on Becker's theory of marriage, compares Becker's research on marriage with that of some scholars interested in intra-marriage distribution, and documents that Becker's students at Chicago were more interested in Becker's Friedmanian models of marriage than in his optimal assignment models.

关键词： Analytical model   Consumer privacy   Economic theory   Information asymmetry   Online fraud   Privacy controls  

摘要： The anonymity of online markets allows traders to easily behave opportunistically. Online marketplaces can lower the uncertainty of participants' identities by adopting preventative controls such as privacy disclosure rules. However, the use of severe privacy controls to engender risk-free environments might sacrifice not only the size of transactions in the marketplace but also the demand for optional security services like escrow services, which constitute a very sizable revenue source for the marketplace services provider. In this vein, we investigate the probability that an integrated online marketplace (IOM) with security services strategically adjusts privacy controls to incentivize traders to self-select both basic transactions and optional security services. Our results show that an integrated marketplace increases the probability of allowing more fraud than is socially optimal by lowering privacy controls. Market risk can be viewed as an asset for an integrated marketplace rather than a liability that inflicts transaction costs on worried traders. Our study argues that marketplaces may differ in terms of their fraud control from what is socially optimal, according to their revenue structures so that the control of online fraud needs to be regulated from the social perspective. However, under certain conditions, integration of this aftermarket will not harm traders or the social welfare. (C) 2009 Elsevier B. V. All rights reserved.

关键词： 电力建设   经济模型   财务指标  

摘要： 在电力建设投资项目评价原有指标体系研究的基础上,对评价指标进行了改进,总结出了一套新投资体制下电力建设项目经济评价的指标体系,以期能使投资者全面地了解项目实施企业的经营能力。最后以一个工程案例为背景分析该经济模型的可行性。

关键词： 工业化   能源消费   能源强度   自回归分布滞后方法  

摘要： 论文应用自回归分布滞后方法(ARDL)与多变量影响模型,分析了中国工业化与不同能源品种消费的关系以及改革开放以来能源强度的驱动机制。结果表明,能源总体消费是中国工业化的充分必要条件;就不同能源品种而言,煤炭消费是工业化的充要条件,但油气消费与非化石能源消费只是工业化的必要条件而非充分条件。不管是长期还是短期,除了非化石能源消费在短期对工业化具有逆向影响外,其他能源品种消费对工业化都具有直接推动作用。自改革开放以来,全要素生产率、工业化与能源政策作为影响能源效率的关键因素,对能源强度的降低具有直接推动效应;对外开放水平的提高有利于中国能源效率的提高,但其效果可能被其他变量所取代;能源价格对能源强度的影响有限,这可能与中国能源领域市场化程度低有关。

关键词： 鲐鱼   生物经济模型   大型灯光围网渔业   群众围网渔业   东、黄海  

摘要： 鲐鱼是我国近海大型围网和群众围网船队主要捕捞种类。如何兼顾两种渔业的利益,并从生物、经济和社会效益来科学制定渔业管理目标,是确保该资源可持续利用的重要研究内容之一。本文根据渔获统计等数据,在理论上模拟了50年内(1948年-2048年)大型围网和群众围网捕捞船队的动态变化,探讨5种方案下各渔业捕捞努力量、鲐鱼资源量、产量及利润,以及与其对应的总利润及总产量的动态变化情况。模拟结果表明:所有方案下,资源量在前10年(1998年-2008年)中都出现较大幅度的减少,随后趋于稳定并维持在较低的水平上。在基准方案下,群众围网船队在捕捞努力量、产量及利润方面占优。其余方案中,大型围网船队最终在捕捞努力量和产量占优,但其利润接近于0。结合累计产量和利润,方案c(降低大型围网成本)由于兼顾了大型围网的经济效益及群众围网的社会效益,可认为是目前适合东黄海鲐鱼长期的管理方式。

关键词： 宏观经济模型   新加坡国立大学   预测报告   增长速度   刘树成   李稻葵   模型分析   国民收入再分配   调整国民  

摘要： 在日前举行的中国宏观经济高层论坛上,厦门大学和新加坡国立大学课题组发布2010年春季预测报告称,今后数年,中国的经济可能难以保持2003～2007年的两位数增长。该课题组运用中国季度宏观经济模型(CQMM)进行预测。预测显示,2010年中国GDP预计可实现9.13%的经济增速,经济复苏迹象明显。但随着M2增速的下降,2011年增长率将回落到8.51%。

关键词： 稳定性   分岔   伪振子法   迭代法  

摘要： 讨论了一类经济模型的稳定性及Hopf分岔.根据特征根给出系统失稳的条件后,利用伪振子法和迭代法得到了Hopf分岔的方向以及周期解的振幅估计,计算式较简洁,最后的数值算例很好地验证了方法的准确性.特别地,当周期解振幅较大时,迭代法的估算更准确.尽管系统失稳后,产生分岔周期解,但适当调整参数大小,仍然可以保证周期解稳定,也就意味着经济的良性发展.