A note on the existence of unique equivalent martingale measures in a Markovian setting

Simple sufficient conditions for the existence of a unique equivalent martingale measure are provided. Furthermore, these conditions give us a handle on situations where an equivalent martingale measure cannot exist. The existence of a unique equivalent martingale measure is of relevance to problems in mathematical finance. Two examples of models for which the question of existence was unresolved are studied. By means of our results existence of a unique equivalent measure up to an explosion time is proved.     

Software for Learning and for Doing Statistics

The community of statisticians and statistics educators should take responsibility for the evaluation and improvement of software quality from the perspective of education. The paper will develop a perspective, an ideal system of requirements to critically evaluate existing software and to produce future software more adequate both for learning and doing statistics in introductory courses. Different kinds of tools and microworlds are needed. After discussing general requirements for such programs, a prototypical ideal software system will be presented in detail. It will be illustrated how such a system could be used to construct learning environments and to support elementary data analysis with exploratory working style.     

Working-time reduction and employment: experiences in Europe and economic policy recommendations

The paper seeks to evaluate the evidence on the employment effectsof the collective working-time reductions in Europe over thepast 20 years. While theoretical analyses produce contradictoryassessments, most empirical studies show positive employmenteffects but take insufficient account of these conditions underwhich the reductions in working time were implemented. Theseconditions for the success of collective working-time reductionsinclude an active training policy designed to minimise skillshortages in the labour market, the modernisation of work organisation,wage increases in conjunction with productivity gains and amore equal income distribution.     

中国农村金融组织生存、变迁及发展

由于农业的弱质性及在国民经济发展中的基础地位，农村金融组织在农村经济及整个国民经济稳定发展中发挥着不可或缺的作用。中国农村金融组织也有一个生存、发展的制度变迁过程。本文在研究了合作经济及农村金融组织在农村经济发展中的作用的基础上，重点研究了法国的农村金融体系在法国国民经济中的作用，并进一步探讨了中国农村金融组织的生存条件、制度变迁及发展。     

高校隐性德育资源的开发与建设

隐性德育问题是当前德育问题的重要前沿性课题。随着德育学科的科学发展以及教育的现代化趋势,重视并充分利用隐性德育资源促进高校大学生的全面发展,已经成为当前高校德育(或思想政治教育)改革的一个重要趋势。在高校中,隐性德育是相对显性德育而言的,是高校整体德育的有机组成部分,隐性德育资源对学生的发展起到潜移默化的影响和塑造作用。本文从高校隐性德育资源的内涵、开发与建设的原则和途径等方面进行阐述,意在引起对高校隐性德育资源的重视,合理开发和建设。     

基于引制一体化的定向战斗部起爆控制研究

采用定向战斗部已成为防空导弹增强战斗部杀伤威力的重要发展方向，但是定向战斗部的应用对起爆控制系统提出了新的要求。本文提出一种利用防空导弹无线电引信与导引头一体化设计（简称引制一体化设计），并应用数据融合实现定向战斗部起爆控制的技术途径。     

会计数据信度与效度的特征性描述——基于会计变量及变量间关系的认识

无形会计数据信度即度量结果的重复性程度,是反映会计数据的客观性指标。效度是判断度量结果即研究对象结果的有效性程度。会计数据的信度与效度的探讨有助于会计信息质量的改善与质量标准的制定,对于进一步展开会计科学的研究也具有一定的意义。本文通过分析会计数据信度与效度的特征性,探讨与验证会计数据信度与效度路径研究方法。     

农业院校促进乡镇经济发展的个案研究

在知识就是第一生产力的今天，乡镇经济的发展已不仅是地方政府、乡镇企业的责任，农业院校在履行其育人、科研功能的同时，更应该发挥其服务社会的功能，为乡镇、县域经济的发展起到巨大的带动、推进作用。文章以位于吉林市昌邑区左家镇的吉林农业科技学院为例，分析农业院校在自身发展壮大的同时对所在地方经济的促进作用，将有高等教育辐射的左家镇与没有高等教育辐射的土门岭镇在人均收入、农林牧渔各项产值等方面进行比较，用翔实、准确的数字表明：农业院校是促进乡镇经济快速发展的主力军。     

Efficiency outcomes of market concentration and managed care

The paper examines how hospital cost efficiency has reacted to extensive horizontal integrations of hospitals and rapid growth of managed care in the US health care industry. Cost efficiency is estimated by using panel data approaches to relax the assumptions for the hospital effects imposed in earlier studies. The paper shows that higher managed care penetration over time is associated with greater hospital efficiency, and higher market concentration is positively associated with efficiency when markets are highly competitive or highly concentrated.     

Violations of Service Fairness and Legal Ramifications: The Case of the Managed Care Industry

Adapted from Chan's (2000) model depicting success of litigation, this paper argues that with the application of various legislation, health maintenance organizations' (HMOs') violations of service fairness to each group: enrollees, physicians, and hospitals give rise to each group's lawsuits against the HMOs. Various authors (Bowen et al., 1999; Seiders and Berry, 1998) indicate that justice concepts such as distributive, procedural, and interactional justice can be applied to the area of service fairness. The violation of these underlying justice principles with HMOs' service unfairness to enrollees, physicians, and hospitals is examined. A general synopsis of the ethical issues in the managed care industry is provided. The various lawsuits launched by each group: enrollees, physicians, and hospitals together with the key statutes used are discussed. This paper also highlights the provisions and ramifications of the 11 April 2000 landmark agreement that Aetna made with Texas Attorney General John Cornyn to settle the 1998 lawsuit brought against the company. Lastly, the current ethical issues in the managed care industry are further discussed. The value of this paper can be adapted to the study of organizations' service fairness violations in other industries or in the educational, governmental, and not-for-profit sectors both nationally and internationally.