The Budgetary Dilemmas of an Ageing Workforce: A Scenario Study of the Public Sector in the Netherlands

This paper studies the consequences (particularly the budgetary effects) of alternative senior-worker policies in the Dutch public sector. Special attention is paid to: the ongoing process of population ageing; the interaction between the participation in senior-worker schemes and the use of disability and unemployment schemes; and the effect of labour participation of older workers on employment opportunities for younger workers. From the scenario analysis, it appears that policies aimed at influencing the participation in senior-worker schemes will not result in substantial savings. The main conclusion of the study is that ageing of the labour force will lead to substantial cost increases anyway, whatever the early-retirement policy.     

Cultural barriers in migration between OECD countries

This paper uses a unique set of new indicators enabling us to test the effects of cultural barriers on migration between OECD countries. Using data on migration flows between 22 OECD countries over the period 1990–2003, we find strong evidence for the negative effect of cultural differences on international migration flows. Cultural barriers do a much better job in explaining the pattern of migration flows between developed countries than traditional economic variables such as income and unemployment differentials.     

Fibonacci index and stability number of graphs: a polyhedral study

The Fibonacci index of a graph is the number of its stable sets. This parameter is widely studied and has applications in chemical graph theory. In this paper, we establish tight upper bounds for the Fibonacci index in terms of the stability number and the order of general graphs and connected graphs. Turán graphs frequently appear in extremal graph theory. We show that Turán graphs and a connected variant of them are also extremal for these particular problems. We also make a polyhedral study by establishing all the optimal linear inequalities for the stability number and the Fibonacci index, inside the classes of general and connected graphs of order n.     

Aggregation of coarse preferences

We consider weak preference orderings over a set A _n of n alternatives. An individual preference is of refinement?≤n if it first partitions A _n into ? subsets of `tied' alternatives, and then ranks these subsets within a linear ordering. When ?<n, preferences are coarse. It is shown that, if the refinement of preferences does not exceed ?, a super majority rule (within non-abstaining voters) with rate 1− 1/? is necessary and sufficient to rule out Condorcet cycles of any length. It is argued moreover how the coarser the individual preferences, (1) the smaller the rate of super majority necessary to rule out cycles `in probability'; (2) the more probable the pairwise comparisons of alternatives, for any given super majority rule. Received: 29 June 1999/Accepted: 25 February 2000     

Partial least squares Cox regression for genome-wide data

Most methods for survival prediction from high-dimensional genomic data combine the Cox proportional hazards model with some technique of dimension reduction, such as partial least squares regression (PLS). Applying PLS to the Cox model is not entirely straightforward, and multiple approaches have been proposed. The method of Park et al. (Bioinformatics 18(Suppl. 1):S120–S127, 2002) uses a reformulation of the Cox likelihood to a Poisson type likelihood, thereby enabling estimation by iteratively reweighted partial least squares for generalized linear models. We propose a modification of the method of park et al. (2002) such that estimates of the baseline hazard and the gene effects are obtained in separate steps. The resulting method has several advantages over the method of park et al. (2002) and other existing Cox PLS approaches, as it allows for estimation of survival probabilities for new patients, enables a less memory-demanding estimation procedure, and allows for incorporation of lower-dimensional non-genomic variables like disease grade and tumor thickness. We also propose to combine our Cox PLS method with an initial gene selection step in which genes are ordered by their Cox score and only the highest-ranking k% of the genes are retained, obtaining a so-called supervised partial least squares regression method. In simulations, both the unsupervised and the supervised version outperform other Cox PLS methods.     

Qualitative Heuristics For Balancing the Pros and Cons

Balancing the pros and cons of two options is undoubtedly a very appealing decision procedure, but one that has received scarce scientific attention so far, either formally or empirically. We describe a formal framework for pros and cons decisions, where the arguments under consideration can be of varying importance, but whose importance cannot be precisely quantified. We then define eight heuristics for balancing these pros and cons, and compare the predictions of these to the choices made by 62 human participants on a selection of 33 situations. The Levelwise Tallying heuristic clearly emerges as a winner in this competition. Further refinements of this heuristic are considered in the discussion, as well as its relation to Take the Best and Cumulative Prospect Theory.     

On S-Convexity and Risk Aversion

The present note first discusses the concept of s-convex pain functions in decision theory. Then, the economic behavior of an agent with such a pain function is represented through the comparison of some recursive lotteries.     

Efficiency with Endogenous Population Growth

In this paper, we generalize the notion of Pareto efficiency to make it applicable to environments with endogenous populations. Two efficiency concepts are proposed: ℘‐efficiency and 𝒜‐efficiency. The two concepts differ in how they treat potential agents that are not born. We show that these concepts are closely related to the notion of Pareto efficiency when fertility is exogenous. We prove a version of the first welfare theorem for Barro–Becker type fertility choice models and discuss how this result can be generalized. Finally, we study examples of equilibrium settings in which fertility decisions are not efficient, and we classify them into settings where inefficiencies arise inside the family and settings where they arise across families.     

沙特柔性反恐措施研究

柔性反恐是刚性反恐的必要补充,沙特在武力反恐的同时采取了一系列柔性反恐措施。“去极端化”是柔性
反恐的重要内容之一,包括预防措施、康复项目和善后安抚。其中,预防措施是指从日常生活、学校教育、社会公共信
息的传播和交流等三大层面着力;康复项目是一项囊括了康复组织、康复项目的实施者及辅导过程三方面的综合性计
划;善后安抚则是旨在帮助囚犯重返社会、预防其重新犯罪,帮助释放犯走上正确的人生轨道。三大措施的目的在于
阻止个人成为恐怖主义者,促进卷入恐怖活动个人的康复,提供善后安抚计划以便于被释放者重返社会等。沙特的柔
性反恐措施取得了显著的成效,产生了很大的国际反响,“9
11”事件后反恐话语的主导者美国对此做出积极的反应
并提供一定的支持。     

Scatter Plot and Additional Variables

We often want to complete the interpretation of the usual graphs (x, y) with additional quantitative variables. The Prefmap method (vectorial model) proposes a representation of these additional variables but this representation has some drawbacks when the variables x and y are correlated. To solve this problem, we propose to substitute the coefficients of the linear regression by the coefficient of the PLS regression in the Prefmap method. The graph obtained is made operational thanks to contour lines of quality of representation and it becomes richer than the Prefmap one.