A SAEM algorithm for the estimation of template and deformation parameters in medical image sequences

This paper is about object deformations observed throughout a sequence of images. We present a statistical framework in which the observed images are defined as noisy realizations of a randomly deformed template image. In this framework, we focus on the problem of the estimation of parameters related to the template and deformations. Our main motivation is the construction of estimation framework and algorithm which can be applied to short sequences of complex and highly-dimensional images. The originality of our approach lies in the representations of the template and deformations, which are defined on a common triangulated domain, adapted to the geometry of the observed images. In this way, we have joint representations of the template and deformations which are compact and parsimonious. Using such representations, we are able to drastically reduce the number of parameters in the model. Besides, we adapt to our framework the Stochastic Approximation EM algorithm combined with a Markov Chain Monte Carlo procedure which was proposed in 2004 by Kuhn and Lavielle. Our implementation of this algorithm takes advantage of some properties which are specific to our framework. More precisely, we use the Markovian properties of deformations to build an efficient simulation strategy based on a Metropolis-Hasting-Within-Gibbs sampler. Finally, we present some experiments on sequences of medical images and synthetic data.     

Theorizing indicators

Policymakers and social theorists have increasingly come to rely on social indicators to guide their decisions and theories. Social indicators are also useful in bridging theory and empirical research as well as the traditional gap between policymaking and social theory. The concept of social indicators covers interpretation of cultural signs, simple statistical measures, and complex statistical indexes related to sets of domains. The article views the development of child well-being indicators as central not only in the social welfare field, but as an indicator of future societal conditions, given that children’s lives are especially sensitive to social change. The paper addresses the development of indicators of children’s well-being, arguing that the expansion of the field, the complexity of new domains and indicators, and the position of children as “being” and “becoming”, they are citizens of the present as well as being socialized for the future, illustrates that the next crucial step for the field is to further elaborate theories and models.     

The Favorite-Longshot Bias in Sequential Parimutuel Betting with Non-Expected Utility Players

This paper analyzes a model of sequential parimutuel betting described as a two-horse race with a finite number of noise bettors and a finite number of strategic and symmetrically informed bettors. For generic objective probabilities that the favorite wins the race, a unique subgame perfect equilibrium is characterized. Additionally, two explanations for the favorite–longshot bias—according to which favorites win more often than the market's estimate of their winning chances imply—are offered. It is shown that this robust anomalous empirical regularity might be due to the presence of transaction costs and/or to strategic bettors' subjective attitude to probabilities.     

Unconditional Quantile Treatment Effects Under Endogeneity

This article develops estimators for unconditional quantile treatment effects when the treatment selection is endogenous. We use an instrumental variable (IV) to solve for the endogeneity of the binary treatment variable. Identification is based on a monotonicity assumption in the treatment choice equation and is achieved without any functional form restriction. We propose a weighting estimator that is extremely simple to implement. This estimator is root n consistent, asymptotically normally distributed, and its variance attains the semiparametric efficiency bound. We also show that including covariates in the estimation is not only necessary for consistency when the IV is itself confounded but also for efficiency when the instrument is valid unconditionally. An application of the suggested methods to the effects of fertility on the family income distribution illustrates their usefulness. Supplementary materials for this article are available online.     

Le corps en jeu : les conditions sociales de l’arrêt de travail des footballeurs professionnels

Underlaid by a long-term case study in a professional football club, this analysis of the social conditions that led these players to temporarily stop work when their physical integrity was impaired focuses on relations within the work group. It describes how this process fits into the framework of social relations between various categories of workers who adjust individually and collectively to occupational requirements. While inquiring into the conditions of bringing players physically into play, it focuses on the practices of members of the medical staff whose position within the group is awkward.     

New public management and professionals in the public sector. What new patterns beyond opposition?

The proliferation of reforms in public administration based on the principles and instruments of the “New Public Management” (NPM) have triggered protest from and collective action by many professional groups in various sectors (healthcare, education, justice, social work, research…) and raised questions about the future of professionals working in the public service, particularly as concerns their autonomy. However, after analyzing the situation, it seems that the opposition between NPM and certain professional groups is not the last word in the debate. Should changes be seen as the decline of professional groups and of their autonomy or as a transformation of professional models, an overhaul of professionalism, etc.? Such questions, which current events in France and Europe have brought to the fore, are food for ongoing sociological thought. They are broached here empirically, from the field, applying varied levels of analysis and research. The contributors to this dossier explore the different forms of tension existing between professional groups and NPM.     

Business ethics,company value and ownership structure

This paper examines the effect of ethical performance on the value of a company and the attractiveness of its stocks for major owners; institutional investors and insiders. Using the Ethisphere^® Institute Ethics Quotient to distinguish between ethical and unethical companies, results show that good ethical performance enhanced company value for a sample of 240 large US companies. Furthermore, strong evidence is found that institutional investors are attracted to ethical companies, but that insiders do not show any investment preferences based on the ethical performance of a company.

     

Correction to: Corporate social responsibility and governance

Journal of Management and Governance - The original version of this article contained a mistake. The list of the authors was incorrect. The authors of this article are: Jean-Michel Sahut, Marta...     

PERSONALITY,INFORMATION ACQUISITION,AND CHOICE UNDER UNCERTAINTY: AN EXPERIMENTAL STUDY

This article studies the role of personality in choice under risk and uncertainty. We explore the hypothesis that personality plays a role in decision making in situations of uncertainty but not in situations of risk. In addition to offering support for this main hypothesis, we explore the various pathways through which personality exerts its influence. What we find is that in uncertain environments, where decision makers are able to acquire information about the unknown probability distributions they face, personality variables influence the type of information people acquire, which then influences their choice. Our experimental design brings in two novel aspects of choice under uncertainty: information acquisition and advice. The findings indicate that indeed, under uncertainty, personality matters for choice in a way it does not under risk. Furthermore, the results suggest that personality can play a role at multiple levels, such as people's preferences for certain types of information and the likelihood of following advice. (JEL C90, D03, D81)