Mariage et mobilité sociale en France

La formation des couples est un moment crucial de la reproduction sociale. Pour établir le bilan des transactions sur le marché matrimonial, trois méthodes ont été utilisées : la comparaison des positions sociales des conjoints, la comparaison des caractéristiques sociales de leurs parents, la comparaison des trajectoires sociales des conjoints. La formation d'un couple correspond le plus souvent à la conjonction de deux trajectoires parallèles, ce qui a pour effet de conforter les positions acquises ou d'accompagner les évolutions engagées. Dans d'autres cas, plus rares, le mariage peut accélérer sensiblement la transition à un nouveau statut, ou au contraire freiner voire inverser le déclin d'une trajectoire sociale.Marriage is a crucial stage in social reproduction. To establish the outcome of transactions in the marriage market, three methods have been used: comparison of the social positions of the marriage partners; comparison of the social characteristics of their parents; and comparison of the social careers of the partners. Usually a marriage represents the conjunction of two parallel social careers, the effect of which is to consolidate the positions acquired or to support the evolutions in progress. In more rare cases, the marriage can either appreciably accelerate the transition to a new status, or slow down and even reverse the decline of a social career.

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Cet article est la version révisée et enrichie d'une communication présentée au III^e séminaire franco-soviétique de démographie, à Bordeaux (10–14 octobre 1988).     

A robustness framework for monitoring real options under uncertainty

This paper presents a problem structuring methodology to assess real option decisions in the face of unpredictability. Based on principles of robustness analysis and scenario planning, we demonstrate how decision-aiding can facilitate participation in projects setting and achieve effective decision making through the use of real options reasoning. We argue that robustness heuristics developed in earlier studies can be practical proxies for real options performance, hence indicators of efficient flexible planning. The developed framework also highlights how to integrate real options solutions in firms’ strategic plans and operating actions. The use of the methodology in a location decision application is provided for illustration.     

Maximum likelihood approach to vote aggregation with variable probabilities

The Condorcet-Kemeny-Young statistical approach to vote aggregation is based on the assumption that voters have the same probability of comparing correctly two alternatives and that this probability is the same for any pair of alternatives. We relax the second part of this assumption by letting the probability of comparing correctly two alternatives be increasing with the distance between two alternatives in the allegedly true ranking. This leads to a rule in which the majority in favor of one alternative against another one is given a larger weight the larger the distance between the two alternatives in the true ranking, i.e., the larger the probability that the voters compare them correctly. This rule is not Condorcet consistent and does not satisfy local independence of irrelevant alternatives. Yet, it is anonymous, neutral, and paretian. It also appears that its performance in selecting the alternative most likely to be the best improves with the rate at which the probability increases.We would like to thank Michel Le Breton for his encouragement to examine this question and for his comments, as well as Philippe De Donder, Jean-Yves Duclos, Stephen Gordon, Cyril Téjédo and an anonymous referee for their comments.     

Awareness Promotion About Excessive Gambling Among Video Lottery Retailers

This paper describes and evaluates “As luck would have it,” an awareness program completed by retailers in Quebec Province. This program, which is presented as a two-hour awareness promotion workshop, aimed to inform retailers about excessive gambling. More specifically, it provided answers to the following questions: (1) What is chance and randomness? (2) Is there a link between misunderstanding the concept of chance and excessive gambling? (3) How does one recognise the symptoms of this disorder? (4) How should retailers intervene if they decide to do so? Results showed that retailers developed a better understanding of problem gambling, could recognise its main symptoms, felt more capable of coping with excessive gamblers, and of choosing the most appropriate moment to do so. In the follow-up phase, retailers who had attended the workshop reported that they approached a problem gambler significantly more often than the retailers who had not attended the workshop, and had discussed how to help problem gamblers significantly more often. The practical implications of these results are briefly discussed.     

The dynamics of the population sex ratio in India, 1971-96

This paper reconstructs the trend in the population sex ratio in India between 1971 ad 1996 from available information on changes in sex differentials in mortality in the country since the beginning of the century. It is estimated that, although the mortality of females relative to that of males in India has improved since 1968, the population sex ratio increased between 1971 and 1981, stayed constant between 1981 and 1991, and started to decrease only after 1991. This implies that the recorded decrease and increase in the periods 1971-81 and 1981-91 respectively were both spurious and were the results of undercounts of females in 1971 and 1991. Another implication of this finding is that, owing to the lagged effect of past mortality on current trends in the population sex ratio, this ratio is a bad proxy for use in the study of changes in differential mortality by sex.     

Catastrophe Risk Models for Evaluating Disaster Risk Reduction Investments in Developing Countries

Major natural disasters in recent years have had high human and economic costs, and triggered record high postdisaster relief from governments and international donors. Given the current economic situation worldwide, selecting the most effective disaster risk reduction (DRR) measures is critical. This is especially the case for low‐ and middle‐income countries, which have suffered disproportionally more economic and human losses from disasters. This article discusses a methodology that makes use of advanced probabilistic catastrophe models to estimate benefits of DRR measures. We apply such newly developed models to generate estimates for hurricane risk on residential structures on the island of St. Lucia, and earthquake risk on residential structures in Istanbul, Turkey, as two illustrative case studies. The costs and economic benefits for selected risk reduction measures are estimated taking account of hazard, exposure, and vulnerability. We conclude by emphasizing the advantages and challenges of catastrophe model‐based cost‐benefit analyses for DRR in developing countries.     

Reduced costs propagation in an efficient implicit enumeration for the 01 multidimensional knapsack problem

In a previous work we proposed a variable fixing heuristics for the 0-1 Multidimensional knapsack problem (01MDK). This approach uses fractional optima calculated in hyperplanes which contain the binary optimum. This algorithm obtained best lower bounds on the OR-Library benchmarks. Although it is very attractive in terms of results, this method does not prove the optimality of the solutions found and may fix variables to a non-optimal value. In this paper, we propose an implicit enumeration based on a reduced costs analysis which tends to fix non-basic variables to their exact values. The combination of two specific constraint propagations based on reduced costs and an efficient enumeration framework enable us to fix variables on the one hand and to prune significantly the search tree on the other hand. Experimentally, our work provides two main contributions: (1) we obtain several new optimal solutions on hard instances of the OR-Library and (2) we reduce the bounds of the number of items at the optimum on several harder instances.