Employment protection legislation and job stability: A European cross‐country analysis

Based on Eurostat data on wage employment for the period 1999–2006, this article investigates the dynamics of job tenure across the European Union. The authors’ analysis shows no generalized decline in job tenure, but a trend towards shorter tenure among young workers (aged 15–24 years) in many European countries. Their regression results indicate that this trend is associated with the weakening of employment protection provided by law and by trade unions. Given young workers’ weak individual bargaining power, the trend towards individualization of the employment relationship may thus affect them disproportionately.     

A local moment type estimator for an extreme quantile in regression with random covariates

A conditional extreme quantile estimator is proposed in the presence of random covariates. It is based on an adaptation of the moment estimator introduced by Dekkers et al. (1989 Dekkers, A.L.M., Einmahl, J.H.J., de Haan, L. (1989). A moment estimator for the index of an extreme-value distribution. Ann. Statist. 17:1833–1855.[Crossref], [Web of Science ®] , [Google Scholar]) in the classical univariate setting, and thus it is valid in the domain of attraction of the extreme value distribution, i.e., whatever the sign of the extreme value index is. Asymptotic normality of the estimator is established under suitable assumptions, and its finite sample behavior is evaluated with a small simulation study, where a comparison with an alternative estimator already proposed in the literature is provided. An illustration to a real dataset concerning the world catalogue of earthquake magnitudes is also proposed.     

Using heuristics to find minimal unsatisfiable subformulas in satisfiability problems

In this paper, we propose efficient algorithms to extract minimal unsatisfiable subsets of clauses or variables in unsatisfiable propositional formulas. Such subsets yield unsatisfiable propositional subformulas that become satisfiable when any of their clauses or variables is removed. These subformulas have numerous applications, including proving unsatisfiability and post-infeasibility analysis. The algorithms we propose are based on heuristics, and thus, can be applied to large instances. Furthermore, we show that, in some cases, the minimality of the subformulas can be proven with these algorithms. We also present an original algorithm to find minimum cardinality unsatisfiable subformulas in smaller instances. Finally, we report computational experiments on unsatisfiable instances from various sources, that demonstrate the effectiveness of our algorithms.     

Transport policy and public involvement

This paper examines the possibility of establishing a public space of deliberation concerning transport policy. It deals with the question of whether it is possible to envisage instances of concertation that deflect conflict. Based mostly on French experience with public inquiries on transport infrastructure, it discusses the relevance and applicability of the sociology of collective action, as well as theories of deliberative democracy. The paper's main argument is that concertation does not occur in a vacuum but is instead structured by power relations. It is, therefore, first and foremost an opportunity to express dissatisfaction and frustration. At the same time, public debate represents—perhaps for the same reason—an opportunity to criticize forms of social domination. It thus may give rise to citizen mobilization rather than help contain it, as is often naively expected by its promoters within the public policy administration. Conflict is thus always the actual subject of public debate.     

Formation et calcul des prix : le travail de tarification dans la grande distribution

Sociologists have recently been rasing questions about how prices are set in various markets. Although their seminal studies have explained the many processes and variables that come into play, they do not enable us to describe the concrete procedures whereby prices are actually calculated. This empirical case study explores the sophisticated methods of calculating the prices of products distributed in a French retail hypermarket chain. Three major conclusions are drawn. First of all, the law enters into the delimitation of the “space” for calculating the prices that distributors set for selling to consumers. Secondly, the choice of a procedure for performing the calculation affects the balance of power between marketing professionals in the struggle to control their shares in the value. Thirdly, the “consumer sale price” does not result directly either from the relation between supply and demand or from micronegotiations between suppliers and distributors. Instead, it tends to ensue from the linkage between several, heterogenous “spaces” of calculation. This study describes the actors, tools and know-how involved in defining these spaces.     

Relative Contributions of Treatment-Related Changes in Communication Skills and Dyadic Coping Skills to the Longitudinal Course of Marriage in the Framework of Marital Distress Prevention

Most prior studies of skill-based preventive interventions for couples compare changes in problem-solving behaviors made by treated couples with those made by control couples. Unexpected findings in these studies highlight the need to examine within-group variability in behavior change among treated couples, alternative behavioral domains, including dyadic support and coping, and partners' intended and actual use of strategies taught in the interventions. A 24-month longitudinal study of 109 couples participating in an 18-hour intervention designed to enhance communication and dyadic coping revealed that marital outcomes are enhanced to the extent that (a) wives increase their positive problem-solving behavior and husbands decrease their negative problem-solving behavior over the course of the intervention, and (b) wives and husbands increase their positive dyadic coping behaviors, and husbands decrease their negative dyadic coping behaviors. Moreover, greater postintervention use of strategies taught in the intervention program produced better outcomes, and wives' improvements in positive and negative dyadic coping strengthened associations between strategy use and relationship satisfaction. Discussion emphasizes the importance of devising interventions that target key interpersonal processes and that motivate participants to display newly acquired behaviors.     

Equilibrium,affinity, dissociation constants,IC5O: Facts and fantasies

The interaction between ligands and receptors is often described in terms of 50% inhibitory concentrations (IC50). However, IC50 values do not accurately reflect the dissociation constants (Kd), and the domain of application and precision of proposed approximations for Kd estimation are unclear. The effect of affinity and of experimental conditions on the differences between IC50 and Kd has been assessed from exact mass action law calculations and from computer simulations. Competitions between [¹¹¹In]DTPA‐indium and a few metal‐DTPA complexes for binding to a specific antibody are discussed as a practical example. Exact calculations of competition assays have been implemented in Microsoft Excel and performed for a variety of concentrations of receptor, tracer, and competitor. The results are identical to those of software packages. IC50 is found larger than Kd by less than 20% only when tracer concentration is small compared with Kd and to the receptor concentration and when this receptor concentration is small compared with Kd. Otherwise, Kd and IC50 may be very different and approximations proposed in the literature to obtain Kd values from graphically derived IC50 are not acceptable as soon as the concentrations of tracer or of receptor approach Kd. Under most experimental conditions, IC50 values do not reflect Kd values. Using available software packages to determine and report Kd values would allow for more meaningful comparisons of results obtained under different experimental conditions.