Smallpox vaccine policy: the national debate

As a result of the 2001 anthrax attacks, the U.S. government is trying to forge a plan to handle something much worse: an outbreak of smallpox due to terrorist activity. Here's a look at where the debate stands today.     

The future of managed care: the debate continues

The Patient Access to Affordable Care Act has acted as a catalyst in the health care debate over the future of managed care. The Employee Retirement Income Security Act, once a sacred cow, is now under intense scrutiny. Congress is laying the ground work to create consumer protections in health care, but time in this legislative session may run out. If Congress acts this year, there could be a fundamental shift in the control over health care.     

Revisiting the outsourcing debate: two sides of the same story

Although outsourcing of organisational functions has become a popular practice amongst organisations, the literature provides a myopic and simplistic view of the phenomenon by focusing on either single functions or taking monadic views of a single party. The design of our study overcomes these weaknesses by including the following features: a range of organisational functions were included; the unit of analysis was the outsourcing contract; the level of analysis was at the dyadic level where both service providers and receivers presented their views and the approach was a qualitative one. In practice, this involved interviews with managers in service receiving and providing organisations that were in charge of 10 separate outsourcing arrangements. Using agency theory as a theoretical anchor, we contribute to the outsourcing debate by highlighting its complexity and areas of convergence and divergence between service receivers and providers, thereby suggesting a contingent approach towards implementation of outsourcing arrangements.     

Requiring Connectivity in the Set Covering Problem

Given a bipartite graph with bipartition V and W, a cover is a subset C V such that each node of W is adjacent to at least one node in C. The set covering problem seeks a minimum cardinality cover. Set covering has many practical applications. In the context of reserve selection for conservation of species, V is a set of candidate sites from a reserve network, W is the set of species to be protected, and the edges describe which species are represented in each site. Some covers however may assume spatial configurations which are not adequate for conservational purposes. Indeed, for sustainability reasons the fragmentation of existing natural habitats should be avoided, since this is recognized as being disruptive to the species adapted to the habitats. Thus, connectivity appears to be an important issue for protection of biological diversity. We therefore consider along with the bipartite graph, a graph G with node set V, describing the adjacencies of the elements of V, and we look for those covers C V for which the subgraph of G induced by C is connected. We call such covers connected covers. In this paper we introduce and study some valid inequalities for the convex hull of the set of incidence vectors of connected covers.MSC2000: 90C10, 90C57This authors research was financially supported by the Portuguese Foundation for Science and Technology (FCT).This paper is part of this authors Ph.D. research.     

The quality debate: Consumer Bill of Rights

Inherent in any discussion on quality for a delivered service is understanding what outcomes you want to achieve and assuring that your consumer agrees. The Presidential Commission's Consumer Bill of Rights supports this principle. Its' goals include: strengthening consumer confidence by providing them with a system responsive to their needs and with a credible mechanism to address their concerns; reaffirming the importance of a strong relationship between patients and their health care providers; and, reaffirming the role consumers play in safeguarding their own health. Striking the balance between cost and quality requires all the stakeholders of the health care system to focus on the true issues that impact quality: outcomes, accountability, and consumer satisfaction, however defined.     

投资策略与投资收益:基于计算实验金融的研究

通过计算实验金融方法对不同策略投资者投资收益水平进行了考察,提出了一组Friedman假说不能成立的条件,即:在套利限制、噪音交易以及风险厌恶等因素的共同作用下,具有理性预期能力的套利者并不能获得较BSV投资者更高的资产期望收益水平或者更低的破产概率,故即使从长期来看,理性套利者也不能"消灭"BSV投资者,此时Friedman假说不能成立.     

Strategic sustainability and financial performance: exploring abnormal returns

The ongoing empirical debate about whether SRI is associated, if anything, with subpar or surpassing financial performance is characterized by a somewhat indistinct focus and the infeasibility of tapping the full potential of existing models. By indistinct focus, we mean an analysis based on an aggregation of a myriad of SRI factors that potentially affect a firm’s financial performance. The inability of taking full advantage of existing models is reflected by the fact that studies with European data have not been able to comprehensively account for systematic risk tilts. This paper presents a portfolio analysis that overcomes these issues by analyzing a distinct selection of small and innovative firms. We argue that both their strategic implementation of Corporate Social Responsibility and the general growth in socially responsible investments (SRI) lend themselves to an explanation for positive abnormal returns of this portfolio. We account for the idiosyncratic investment style of SRI by introducing a comprehensive pan-European risk-adjusted portfolio analysis based on the Carhart four-factor model. A novel propensity score matching method in conjunction with the estimation of structural models completes the conventional robustness checks in the literature.     

On Some Polyhedra Covering Problems

Let P ⁰, P ¹ be two simple polyhedra and let P ² be a convex polyhedron in E ³. Polyhedron P ⁰ is said to be covered by polyhedra P ¹ and P ² if every point of P ⁰ is a point of P ¹ P ². The following polyhedron covering problem is studied: given the positions of P ⁰, P ¹, and P ² in the xy-coordinate system, determine whether or not P ⁰ can be covered by P ¹ P ² via translation and rotation of P ¹ and P ²; furthermore, find the exact covering positions of these polyhedra if such a cover exists. It is shown in this paper that if only translation is allowed, then the covering problem of P ⁰, P ¹ and P ² can be solved in O(m ² n ²(m + n)l)) polynomial time, where m, n, and l are the sizes of P ⁰, P ¹, and P ², respectively. The method can be easily extended to the problem in E ^d for any fixed d > 3.     

Covering directed graphs by in-trees

Given a directed graph D=(V,A) with a set of d specified vertices S={s ₁,…,s _d }?V and a function f : S→? where ? denotes the set of positive integers, we consider the problem which asks whether there exist ∑ _i=1 ^d f(s _i ) in-trees denoted by \(T_{i,1},T_{i,2},\ldots,T_{i,f(s_{i})}\) for every i=1,…,d such that \(T_{i,1},\ldots,T_{i,f(s_{i})}\) are rooted at s _i , each T _i,j spans vertices from which s _i is reachable and the union of all arc sets of T _i,j for i=1,…,d and j=1,…,f(s _i ) covers A. In this paper, we prove that such set of in-trees covering A can be found by using an algorithm for the weighted matroid intersection problem in time bounded by a polynomial in ∑ _i=1 ^d f(s _i ) and the size of D. Furthermore, for the case where D is acyclic, we present another characterization of the existence of in-trees covering A, and then we prove that in-trees covering A can be computed more efficiently than the general case by finding maximum matchings in a series of bipartite graphs.     

Intermediaries in the relevance-gap debate: A systematic review of consulting roles

A highly contested issue in management science is its relevance to practice. Despite third parties’ potentially significant role in changing the interaction between divided parties, the long-standing literature on the relevance gap has paid third parties little systematic attention. Drawing on a boundary-spanning perspective, and the concept of brokerage in particular, we review how the consultant role is discussed as an intermediary third party between management science and management practice. Based on a systematic literature review of 133 articles, we identify different intermediary consultant roles linking management science to management practice. Our findings detail how the practices associated with intermediary consultant roles performed by academics or practitioners relate to several key relevance criteria, how management knowledge flows when including intermediaries and how intermediaries in different roles relate to different audiences. Based on the findings, we develop a third-party model of intermediary consultant roles and knowledge flows. The model indicates the theoretical significance of third parties in shaping the interaction and knowledge flows between management science and management practice and has theoretical implications for understanding the persistence of the relevance gap. Regarding practical implications, we suggest how management scientists could target third parties as new key practitioner audiences. Considering third parties, and thus moving away from a two-party view, opens up promising directions for further research on the roles and role shifts of various intermediary actors and on how different intermediary audiences may appreciate different types of academic knowledge.     

价格上涨环境下供应链的渠道协调机制研究

研究了在零售市场价格上涨环境下供应链的渠道协调政策:中期退货与期终退货策略. 结果表明:在合理设计批发价格和退货折扣模式下,两种策略组合能够实现总体的协调,并保 证双赢的结果,而且给出了一组协调机制. 结论拓展了Terry 对价格下降环境下的渠道协调机 制的研究结果.     

A guide to the upcoming health reform debate

AT the 1992 ACPE National Institute, several hundred physician executives actively participated in a debate on three competing visions for the health care system in the United States. This new column in the journal attempts to further this process by providing information on policy positions of relevance to College members. While the College does not advocate a particular position, the College encourages individual members to contact the interest group of their choice and get involved in the health policy debate. In this first column, one of the proposals currently being discussed is summarized.     

Preemptive Machine Covering on Parallel Machines

This paper investigates the preemptive parallel machine scheduling to maximize the minimum machine completion time. We first show the off-line version can be solved in O(mn) time for general m-uniform-machine case. Then we study the on-line version. We show that any randomized on-line algorithm must have a competitive ratio m for m-uniform-machine case and ∑_{i = 1}^m1/i for m-identical-machine case. Lastly, we focus on two-uniform-machine case. We present an on-line deterministic algorithm whose competitive ratio matches the lower bound of the on-line problem for every machine speed ratio s≥ 1. We further consider the case that idle time is allowed to be introduced in the procedure of assigning jobs and the objective becomes to maximize the continuous period of time (starting from time zero) when both machines are busy. We present an on-line deterministic algorithm whose competitive ratio matches the lower bound of the problem for every s≥ 1. We show that randomization does not help.     

上海股票市场股票收益率因素研究

根据上海股票市场从1995 年7 月到2000 年6 月所有A 股股票的月收益率、价格、市值和 公司财务数据,利用Fama-Macbeth 回归分析方法及构造动态组合方法,分析总市值、流通市值、 价格、账面市值比、市盈率、账面资产负债比等因素对股票回报率的影响. 发现上海股票市场具 有显著的市值效应、账面市值比效应、市盈率效应和价格效应. 这些效应不能用股票的beta 值 来解释. 同时发现Fama- French 的三因子模型不能完全解释这些效应,但在三因子模型的基础 上再加上一个市盈率因子可以很好地解     

异质信念、卖空限制与股票收益——基于中国证券市场的分析

本文通过构建换手率分离模型计算未预期交易量,并以此作为异质信念的度量指标,探讨其对股票收益的解释能力.依据异质信念程度高低分组发现,异质信念越大的股票组合当期收益越高、未来一期收益越低,这一差异对小规模公司股票最为明显;将异质信念引入CAPM和Fama-French三因子模型,得到异质信念对股票当期收益的影响显著为正、对未来一期收益的影响显著为负;在进一步考虑了流动性、动量效应等因素后,结论依然成立;但针对2010年后允许卖空的股票,异质信念对股票未来一期收益的影响不再显著.本文基于中国证券市场的制度环境,一方面验证了Miller理论的有效性,同时也发现引入卖空机制能在一定程度上减弱异质信念导致的资产定价偏差.     

Managing consumer returns in high clockspeed industries

In this study, we address control policies to manage the collection of products that have been returned by consumers to retailers after they have been sold. Specifically, we model a consumer returns process where the operational decision of interest is the frequency in which returns are picked up from a collection point and then processed at a centralized location. Returns decay in value over time according to their industry clockspeed. Hence there is an intrinsic tradeoff in the decision – a longer interval between collections not only reduces transportation cost, but also reduces the value of asset recovery.We analyze a stylized model with a single collection point and a centralized returns processing center. Given an asset decay rate and a fixed transportation cost we determine the optimal collection interval. We later expand the analysis to the case of a capacitated returns processing center. We also explore the value of information (number of returns held at the collection point) sharing between a collection point and the central processing facility. We find that the voi is quite sensitive to parametric settings ranging upwards to over 20% with a median value of 5.0%. We find that the voi increases with respect to the asset value decay rate and the rate of returns, while it decreases with respect to the shipping cost.     

Selected debate from the arena of knowledge management: new endorsements for established organizational practices

Management theorists and practitioners have been allured recently to the contemporary field of knowledge management. This is a burgeoning subject that has enticed the involvement of specialists from established domains that are broad based in themselves: strategy, organizational behaviour, operations and information technology. In arguing the importance of knowledge in the strategic purpose of the organization, authorities essentially endorse practices that have been supported in the past: practices that appreciate the social context of knowledge. This paper reviews the debates in strategic theory that support the contemporary 'knowledge-based' view of the organization, and describes how established practices relating to knowledge transfer and creation have been recently revitalized.     

Planning reform beyond planning: the debate on an integrated Environment and Planning Act in the Netherlands

Land-use plans serve a dual function. On the one hand, they are programmes for future development, plans for action. On the other hand, they have a regulative function in relation to construction and land use. This paper investigates how the interplay between these functions is playing a role in the current debate about the new integrated Environment and Planning Act (Omgevingswet) in the Netherlands. Initially, the government proposed abolishing local land-use plans and replacing them with a system of by-laws. However, this proposal did not survive the debate on this bill. This paper will shed light on the relationships between planning and regulation by analysing that debate.