Safety of the U.S. food supply: consumer concerns and behaviour

To examine consumer concern about food safety, identify characteristics of those most concerned, and determine behavioural responses to concerns, we used mailed questionnaires to survey a random sample of 630 adults. Eighty-eight percent of respondents were very or somewhat concerned about safety of the food supply. Subjects perceived greatest likelihood of harm from chemicals and lowest likelihood of harm from bacterial contamination. Relative to other concerns about food such as cost or taste, food safety ranked low. Because the concern was across all ages, education levels, genders, and places of residence, we were unable to define a type of person most likely to be concerned about food safety. Less than half the subjects had changed dietary behaviour in response to food safety concerns. Foods reduced or eliminated from the diet most often were meats, fruits, eggs and vegetables. The findings indicate that consumers need risk assessment education and help in making food choices that do not compromise diet quality.     

Majority Voting in Multidimensional Policy Spaces: Kramer–Shepsle versus Stackelberg

We study majority voting over a bidimensional policy space when the voters’ type space is either uni‐ or bidimensional. We study two voting procedures widely used in the literature. The Stackelberg (ST) procedure assumes that votes are taken one dimension at a time according to an exogenously specified sequence. The Kramer–Shepsle (KS) procedure also assumes that votes are taken separately on each dimension, but not in a sequential way. A vector of policies is a Kramer–Shepsle equilibrium if each component coincides with the majority choice on this dimension given the other components of the vector. We study the existence and uniqueness of the ST and KS equilibria, and we compare them, looking for example at the impact of the ordering of votes for ST and identifying circumstances under which ST and KS equilibria coincide. In the process, we state explicitly the assumptions on the utility function that are needed for these equilibria to be well‐behaved. We especially stress the importance of single‐crossing conditions, and we identify two variants of these assumptions: a marginal version that is imposed on all policy dimensions separately, and a joint version whose definition involves both policy dimensions.     

利用层次分析法合理布局企业网点

随着中国市场的逐渐成熟、完善,更多的外企带着自己的产品来到中国,同时市场的竞争也更加剧烈。企业要不断加强售后服务、物流配送、供货周期等各个环节,增加自己产品的市场竞争力,合理布局企业网点至关重要,文章通过层次分析法讨论如何在国内个城市进行合理布局,以在物流配送、供货周期上实现最大的竞争力。     

承发包模式的价值原理

理解建筑生产活动的原理,是比较和推行不同承发包模式的基础.文章将一个建筑工程项目生产活动划分为设计、施工和管理三种类型,并阐释了各自的工作原理,包括设计的三阶段划分、设计与施工的协作,以及工程管理的工作内容;进一步分析了各项活动对于业主的价值.文章为不同承发包模式之间的比较提供了一个分析的框架;为政府主管部门进一步研究市场准入、招投标、建筑许可等监管政策的改革,合理调整设计、施工单位的分工范围,促进行业按照建筑生产活动基本规律科学发展提供了理论上的支持;为业主选择合理的项目发包模式,建筑业相关企业探索各自发展方向提供了理论上的指导.     

客专大站到发线运用随机机会约束模型与算法研究

在考虑到发线运用过程中不确定性因素的基础上,研究旅客列车停站时间和接续时间随机变动情况下客专大站到发线运用优化问题,以提高车站作业效率和方便旅客乘降为优化目标,建立了到发线运用的随机机会约束规划模型.通过将模型中的随机机会约束转化为相应的确定性等价形式,从而将随机规划模型转化为确定性模型,并设计了解决该问题的蚁群算法.算例表明该随机机会约束规划模型能取得可靠性更高的到发线运用计划.     

Ex Ante Skewness and Expected Stock Returns

We use option prices to estimate ex ante higher moments of the underlying individual securities’ risk‐neutral returns distribution. We find that individual securities’ risk‐neutral volatility, skewness, and kurtosis are strongly related to future returns. Specifically, we find a negative (positive) relation between ex ante volatility (kurtosis) and subsequent returns in the cross‐section, and more ex ante negatively (positively) skewed returns yield subsequent higher (lower) returns. We analyze the extent to which these returns relations represent compensation for risk and find evidence that, even after controlling for differences in co‐moments, individual securities’ skewness matters.     

FDI对我国税收政策敏感性分析

通过对我国1985-2006年间外商直接投资、税收优惠额以及外资企业有效税率之间的协整检验,计算了外商直接投资对税收优惠额和有效税率的敏感度系数。通过方差分解,指出有效税率对吸引FDI的贡献度比税收优惠额对吸引FDI的贡献度更为显著。通过脉冲响应分析发现,税收政策的变动在早期对吸引外商直接投资的影响较为明显;从长期来看,其影响力会随着时间而逐渐衰减,最终趋于平稳。本文利用以上结果,分析了"两税合一"对我国吸引外商直接投资的动态作用机制。