Modeling the Effectiveness of Respiratory Protective Devices in Reducing Influenza Outbreak

Outbreaks of influenza represent an important health concern worldwide. In many cases, vaccines are only partially successful in reducing the infection rate, and respiratory protective devices (RPDs) are used as a complementary countermeasure. In devising a protection strategy against influenza for a given population, estimates of the level of protection afforded by different RPDs is valuable. In this article, a risk assessment model previously developed in general form was used to estimate the effectiveness of different types of protective equipment in reducing the rate of infection in an influenza outbreak. It was found that a 50% compliance in donning the device resulted in a significant (at least 50% prevalence and 20% cumulative incidence) reduction in risk for fitted and unfitted N95 respirators, high‐filtration surgical masks, and both low‐filtration and high‐filtration pediatric masks. An 80% compliance rate essentially eliminated the influenza outbreak. The results of the present study, as well as the application of the model to related influenza scenarios, are potentially useful to public health officials in decisions involving resource allocation or education strategies.     

零售商长期后悔规避的供应链网络动态均衡

本文研究了基于时变随机需求的供应链网络动态均衡。由于需求的不确定性和季节性，网络中的零售商会考虑缺货后悔和存货后悔的负效用，基于长期后悔规避效用做出最优决策。利用变分不等式，刻画了网络中制造商层、考虑长期后悔规避效用的零售商层和需求市场层的均衡决策行为。通过数值算例，基于三种长期后悔情形分析了零售商长期后悔规避行为对其均衡订购量、利润、后悔值的影响。研究结果表明，零售商的长期后悔规避程度在不断增加、保持不变，不断减少这三种情况下，对其均衡订购量、利润、后悔值的影响不同。研究结论将指导供应链网络中企业，基于长期后悔规避制定最优决策。     

基于旧件质量和“以旧换再”补贴的分级定价研究

以旧换再补贴政策已经在我国试点施行，相关原型新品和再制品的市场购买行为和企业定价决策受此影响。根据传统销售和售后渠道以及消费者持有旧件质量的不同细分市场，考虑到消费者的"以旧换再"偏好程度构建了制造商分级定价利润模型并分段优化，得到了"以旧换再"补贴下的最优分级定价决策，面向企业给出了旧件分级再制造的成本条件，面向政府给出了授予企业产品补贴资格的参考依据。考虑到再制造领先企业和一般企业再制造条件的不同，采用算例分析展示了补贴对领先企业及一般企业再制造分级定价决策的影响，并分析了消费者"以旧换再"偏好程度的变化对企业分级再制造决策的影响。结果表明，分级定价可以提高再制造系统的整体利润；换购补贴对促进再制造领先企业与一般企业再制造体系发展的积极作用不同，政府应根据产业及企业特点结合其他举措选择实施补贴的时机和补贴比例。     

基于非排它性互换合约的管理层激励研究

管理者进行金融衍生品市场的非排它性股权互换交易会降低报酬合约的事后激励强度,并对企业价值和风险产生影响.本文在管理者可同时影响企业风险和企业价值的条件下,构建基于股权互换避险交易的管理者激励薪酬动态博弈模型.结果表明,当管理者投入产出效率高于某临界值时,互换避险的存在不会降低激励合约的强度;否则激励合约强度的减弱程度随...     

Requirement or Promise? An Analysis of the First‐Mover Advantage in Quality Contracting

Quality contracting is critical and challenging due to the many unique issues related to quality. In this study, we analyze the first‐mover right in quality contracting by considering two different strategies for the buyer: the quality requirement strategy (QR) where buyer moves first by posting quality requirement to suppliers and quality promise strategy (QP) where buyer voluntarily gives up the first‐mover right to suppliers to ask them to promise quality. We study which strategy (1) better encourages suppliers' quality improvement efforts and (2) leads to a higher expected profit for the buyer. To analyze the drivers behind the buyer's choice between QR and QP, we start with the basic model where buyer faces only one supplier who has the opportunity to make quality improvements. We then gradually add other business features such as information asymmetry and supplier competition, analyzing how each feature adds/changes the driving forces and how they interact in the buyer's decision between QR and QP. We consider both the case where the wholesale price is fixed (when the buyer has the power to dictate price or price is set by the market) and the case where the wholesale price is included as a variable (when price is part of the negotiation). We find that QP always leads to the first‐best quality efforts from the supplier(s) while QR limits their efforts. However, this does not guarantee higher expected profit for the buyer under QP. We provide insightful guidelines in buyer's choice between QP and QR. This research enriches the limited literature on quality contracting with quality improvement opportunity and asymmetric information.     

基于FIGARCH模型的地产股对金融股市场影响分析

2008年美国金融危机爆发后,房地产市场与金融市场的关系越来越受到人们的重视.本文以地产股指数变化情况代表房地产市场的整体发展趋势,选取中国深圳证券交易所地产股和金融股为研究对象,利用能够兼顾收益与尾部风险相关性测度的FIGARCH模型,探讨中国地产股对金融股波动及收益的影响;并以次贷危机爆发为界将样本分成两部分进行对比分析.结果表明,我国地产股整体行情指数的波动风险和收益对金融股股票均具有显著的正向影响;地产波动风险在危机前的影响大于危机后,而地产收益的影响则在危机后更大.研究结论有助于相关部门制定更合理的调控和监管政策,促进中国股市更健康的发展.     

Minimum degree, edge-connectivity and radius

Let G be a connected graph on n≥4 vertices with minimum degree δ and radius r. Then $\delta r\leq4\lfloor\frac{n}{2}\rfloor-4$ , with equality if and only if one of the following holds:

1. G is K ₅,
2. G?K _n ?M, where M is a perfect matching, if n is even,
3. δ=n?3 and Δ≤n?2, if n is odd.

This solves a conjecture on the product of the edge-connectivity and radius of a graph, which was posed by Sedlar, Vuki?evi?, Aouchice, and Hansen.     

土地市场化是否必然导致城乡居民收入差距扩大——基于中国23个省(自治区、直辖市)面板数据的检验

本研究利用2003～2008年间我国23个省(自治区、直辖市)的面板数据进行计量检验,重点考察土地市场化对城乡居民收入差距的影响,藉以探讨缩小城乡居民收入差距的路径。研究结果表明,土地市场化水平的提高并不必然导致城乡居民收入差距扩大,土地市场化水平与城乡居民收入差距之间呈现倒U型关系。随着土地市场化水平的提高,城乡居民收入差距不断扩大,直至土地市场化水平达到25.33%。当土地市场化水平达到25.33%时,城乡居民收入差距达到最大;当土地市场化水平大于25.33%后,城乡居民收入差距开始缩小。由于中国目前相当多的地区土地市场化水平低于这一临界值,现阶段土地市场化水平对城乡居民收入差距的影响处于正向作用阶段。要缩小城乡居民收入差距,中国政府应该不断加大土地市场化改革的力度,不断强化市场机制在配置土地资源中的作用,努力消除各种非市场因素的限制,以尽快跳出土地市场化的"低水平陷阱"。     

基于理论演进角度的组织承诺研究综述

结合1960年以前有关对承诺的研究,将组织承诺的发展过程大致划分为背景、兴起,发展和创新四个阶段;基于理论演进的角度,评述不同阶段组织承诺基础的理论根基与来源,关注于组织承诺维度的发展与内涵,探讨不同研究阶段中组织承诺测量方法的区别与联系,分析已有研究中组织承诺的前因变量与结果变量以及组织承诺在不同文化情境中的研究现状;总结组织承诺理论演进过程的发展特征,提出组织承诺未来研究的若干发展方向。     

会计理论与实务研究的现状与展望——中国会计学会高等工科院校分会第15届学术年会综述

介绍了"中国会计学会高等工科院校分会2008年学术年会(第15届学术年会)暨中央在鄂集团企业财务管理研讨会"的概况,并分内部控制与审计、资本市场与财务、会计准则与财务报告、会计教学及其他和中央在鄂集团企业财务5个专题简要介绍了学术交流的内容.