Intermediate preferences and Rawlsian arbitration rules

Given the preferences of two agents over a finite set of alternatives, an arbitration rule selects some fair compromise. We study the idea that more consensus should not be harmful: the closer your preferences are to mine (in the sense of Grandmont's (1978) intermediate preferences), the better I like the selected alternative. We describe several Pareto optimal rules satisfying this principle. If, in addition, a condition akin to Suppes' (1966) grading principle is imposed, the rule must always choose an alternative maximizing the welfare of the worst-off agent, measured by the number of alternatives that he finds worse than the chosen one.Stimulating discussions with H. Moulin and helpful comments from J. Crémer are gratefully acknowledged. The author also wishes to thank a referee and an associate editor for challenging remarks. This research was partly supported by a CAFIR grant from the Université de Montréal.     

An Analysis of Firms' Compliance to Minimum Wage Legislation

The growth of long-term unemployment is the main reason behind the persistence of high rates of unemployment in Western Europe. The paper presents the two main theories, duration dependency and sorting, that have been used to account for emergent and persistent long-term unemployment. Both theories are hysteresis theories in the sense that they explain how the actual level of unemployment can be a function of past unemployment. Against this background the paper examines the evolution of long-term unemployment in Sweden and its demographic composition. The focus is on what has happened to long-term unemployment during the economic recovery experienced by Sweden and on the role of labour market policy measures targeted towards the long-term unemployed in overcoming unemployment persistence. It is shown that there was a significant time-lag before the recovery made inroads into the ratio of long-term unemployment. There was a frunsifory, but also a permanent hysteresis effect. The reaction to the recovery varied between age groups, long-term unemployment among older workers showing most persistence. There was an interaction effect in that the policy measures helped the long-term unemployed take advantage of the recovery. The authors then introduce the concept of a nuturul rule of long-ferm unemployment (NAIRLU) and make empirical estimates of this rate for Sweden. The character and composition of the Swedish natural rate of longterm unemployment is then examined.     

Beyond support in two-stage variable selection

Numerous variable selection methods rely on a two-stage procedure, where a sparsity-inducing penalty is used in the first stage to predict the support, which is then conveyed to the second stage for estimation or inference purposes. In this framework, the first stage screens variables to find a set of possibly relevant variables and the second stage operates on this set of candidate variables, to improve estimation accuracy or to assess the uncertainty associated to the selection of variables. We advocate that more information can be conveyed from the first stage to the second one: we use the magnitude of the coefficients estimated in the first stage to define an adaptive penalty that is applied at the second stage. We give the example of an inference procedure that highly benefits from the proposed transfer of information. The procedure is precisely analyzed in a simple setting, and our large-scale experiments empirically demonstrate that actual benefits can be expected in much more general situations, with sensitivity gains ranging from 50 to 100 % compared to state-of-the-art.     

Does any mother’s body odor stimulate interest in mother’s face in 4‐month‐old infants?

Little is known about the effects of olfaction on visual processing during infancy. We investigated whether and how an infant's own mother's body odor or another mother's body odor affects 4‐month‐old infants’ looking at their mother's face when it is paired with a stranger's face. In Experiment 1, infants were exposed to their mother's body odor or to a control odor, while in Experiment 2, infants were exposed to a stranger mother's body odor while their visual preferences were recorded. Results revealed that infants looked more at the stranger's female face in presence of the control odor but that they looked more at their mother's face in the context of any mother's body odors. This effect was due to a reduction of looking at the stranger's face. These findings suggest that infants react similarly to the body odor of any mother and add to the growing body of evidence indicating that olfactory stimulation represents a pervasive aspect of infant multisensory perception.     

Who's Who in Networks. Wanted: The Key Player

Finite population noncooperative games with linear‐quadratic utilities, where each player decides how much action she exerts, can be interpreted as a network game with local payoff complementarities, together with a globally uniform payoff substitutability component and an own‐concavity effect. For these games, the Nash equilibrium action of each player is proportional to her Bonacich centrality in the network of local complementarities, thus establishing a bridge with the sociology literature on social networks. This Bonacich–Nash linkage implies that aggregate equilibrium increases with network size and density. We then analyze a policy that consists of targeting the key player, that is, the player who, once removed, leads to the optimal change in aggregate activity. We provide a geometric characterization of the key player identified with an intercentrality measure, which takes into account both a player's centrality and her contribution to the centrality of the others.     

Inferring multiple graphical structures

Gaussian Graphical Models provide a convenient framework for representing dependencies between variables. Recently, this tool has received a high interest for the discovery of biological networks. The literature focuses on the case where a single network is inferred from a set of measurements. But, as wetlab data is typically scarce, several assays, where the experimental conditions affect interactions, are usually merged to infer a single network. In this paper, we propose two approaches for estimating multiple related graphs, by rendering the closeness assumption into an empirical prior or group penalties. We provide quantitative results demonstrating the benefits of the proposed approaches. The methods presented in this paper are embeded in the R package simone from version 1.0-0 and later.     

The use of military bunkers by the European badger and red fox in Western Europe

Urban Ecosystems - Intensification of agriculture and land consolidation policy induced the removal of most natural features from farmland, reducing the habitat of many wild species. Abandoned WWII...     

Every Choice Function Is Backwards‐Induction Rationalizable

A choice function is backwards‐induction rationalizable if there exists a finite perfect‐information extensive‐form game such that for each subset of alternatives, the backwards‐induction outcome of the restriction of the game to that subset of alternatives coincides with the choice from that subset. We prove that every choice function is backwards‐induction rationalizable.