Composition-consistent tournament solutions and social choice functions

This paper introduces a new axiom for choice in preference profiles and tournaments, called composition-consistency. A social choice function is composition-consistent if it is non-sensitive to the cloning of one or several outcomes. The key feature of the composition consistency property is an operation concept called multiple composition product of profiles. The paper provides a brief overview of some social choice functions studied in the literature. Concerning the tournament solutions, it is proved that the Top Cycle, the Slater and the Copeland solutions are not composition-consistent, whereas the Banks, Uncovered Set, TEQ, Minimal Covering Set are composition-consistent. Moreover, we define the composition-consistent hull of a solution as the smallest composition-consistent solution containing . The composition-consistent hulls of the Top cycle and Copeland solutions are specified, and we give some hints about the location of the hull of the Slater set. Concerning social choice functions, it is shown that Kemeny, Borda and Minimax social choice functions are not composition-consistent, whereas the Paretian one is composition-consistent. Moreover, we prove that the latter is the composition-consistent hull of the Borda and Minimax functions.     

Changes in the social definition of early childhood and the new forms of symbolic violence

Conclusion The nursery school may be considered an institution and a market where the habits produced by the family are moulded, developed and standardized; thus, it is confronted with an objective definition of early childhood embedded in pedagogical practices. The proper objective of a sociology of nursery-school practice is the analysis of the lag between the functions delegated to the school by the different social classes and the functions which it objectively tends to fulfill. Here we have the best test of the lag between the pedagogic demands of the different classes and what the schools supply-which is very abstract, with results that are only visible at a later stage in the school career. It is not so much a question of learning to read or of preparing to do so (the acquisition of certain logical operations or a developed sensitivity, of acquiring a few I.Q. points). This learning takes place through many varied activities which apppear to be far from the learning function.All told, the conditions for understanding nursery-school exercises flow from the conditions for inventing these exercises. For instance, in games of manipulation, construction, classifying various objects, is not some knowledge of Piaget (at least in the sense of some psychologikal knowledge) needed to understand that practical manipulation is also logical manipulation, to see in cube games the learning of logic? Similarly, the language naïveté cultivated in language games is a clever naïveté, which supposes for example a cultured re-discovery of popular archaic language or of child talk. p ]Is it not likely to appear as pure childishness to those who, without the ncessary cultural knowledge, do not have the keys to decipher these ostensibly naïve exercises? Similarly, the conditions for understanding children's drawings as artistic learning (and the nursery school as an educational institution) are the very conditions for understanding modern art as art.It is not just a matter of perception and understanding; as the objective definition of early childhood proper to the different social classes becomes pervasive both in the relationship with school and in the socialization practices of the family, it patterns the children's habitus (as long-lasting internalized dispositions), which in turn influence the child's behavior and attitude towards school.The perception categories and the different forms of treatment of young children appropriate to each social class are not simply the result of the diffusion of definitions of early childhood produced by the autonomous evolution of scientific and artistic disciplines. They are the products of all the social and cultural conditions which define the class situation. We may also wonder whether at least some pedagogy and certain types of exercises do not presume that the child has socially marked attitudes, produced in some classes by family inculcation. For instance, a general attitude of disinterested interest is required by a pedagogy offering multiple activities and open to an attitude of active research and exploration. Does not this attitude suppose as an existential possibility the condition of social classes protected from economic pressure and from the urgency of immediate life, a general attitude towards life nearer to leisure than to the constraints of work?Thus, in confronting supply with demand—here even less than elsewhere-there is no question of comparing the expectations arising from users' opinions with the program offered in the official definition of the institution. The expectations are those which arise from objective determinations inherent in each social group, the forms of treatment and perception of early childhood. To analyze the program-and therefore to ascertain the social conditions governing the use of the nursery school—the dominant definition of early childhood on which the institution is founded must be brought to light. Moreover, the way in which this definition is written into the curriculum (and, subsequently, into pedagogical practice) must also be studied. This implies that the preliminary condition for a sociological analysis of the functions performed by the nursery school for the different social classes would be an analysis of a) the components of this dominant definition of early childhood and b) of the social conditions in those groups which make it possible to identify these components.We wish to thank P. Bourdieu for his advice during our research. R. Collins provided useful suggestions after reading the first version of this paper.     

Understanding changes in Māori incomes and income inequality 1997–2003

This paper examines recent changes in weekly income levels and dispersion for Māori, New Zealand’s indigenous ethnic group. Changes in the Māori income distribution between 1997 and 2003 reflect rapid increases in economic growth and employment rate. A reduced proportion of people had zero or benefit-level incomes and a higher proportion had high incomes. Income inequality declined for working-aged Māori and was stable for employed Māori. The average income gap between Māori and Europeans declined. The increased Māori employment rate during this period was the single most important driver of changes in the Māori income distribution.

An experimental investigation of transitivity in set ranking

A decision under ‘complete uncertainty’ is one where the decision maker knows the set of possible outcomes for each decision, but cannot assign probabilities to those outcomes. This way, the problem of ranking decisions is reduced to a problem of ranking sets of outcomes. All rankings that have emerged in the literature in this domain imply transitivity. In the current study, transitivity is subjected to an empirical evaluation in two experiments, where subjects are asked to choose between sets of monetary consequences. After analysis with a Bayes Factor, very few violations of transitivity were found. It can be concluded that transitivity seems a plausible condition for the ranking of sets of monetary consequences.     

Peer Victimization,Self‐esteem,and Ego Resilience Types in Adolescents: A Prospective Analysis of Person‐context Interactions

This study examined bidirectional, longitudinal associations between peer victimisation and self‐esteem in adolescents, and tested for moderator effects of undercontrolling, overcontrolling, and ego‐resilient personality types in these associations. Data were used from 774 adolescents ages 11–16 years who participated in a three‐wave (i.e., 2005, 2006, and 2007) longitudinal study. Structural equation modelling analyses in Mplus demonstrated that, controlling for earlier levels of self‐esteem, self‐reported peer victimization was associated with lower self‐esteem across one‐year time intervals. Vice versa, however, low self‐esteem was not predictive of subsequent self‐reported victimization. Evidence was also found for a moderator effect of personality type on the longitudinal associations between self‐esteem and victimization. Only in the subgroup of overcontrolling adolescents was lower self‐esteem related to subsequently higher levels of peer victimization; their undercontrolling and ego‐resilient peers were unaffected.     

Child custody issues and co‐occurrence of intimate partner violence and child maltreatment: controversies and points of agreement amongst practitioners

The situation of families undergoing separation in a context of co‐occurrence of intimate partner violence (IPV) and child maltreatment raises certain issues related to child custody. The results presented in this paper were collected and analysed within the framework of a qualitative study aiming to identify the principal points of agreement and the main controversies amongst practitioners in several different types of organizations. Focus groups were held with a total of 43 practitioners from six different settings concerned with child custody in cases of co‐occurrence of IPV and child maltreatment. Although they agreed on the importance of ensuring the safety of victims of violence, their views diverged on three points: (1) the importance of preserving the father–child relationship; (2) collaboration between voluntary organizations and semi‐voluntary or legal agencies; and (3) consideration of cultural differences.     

Semiparametric Bayesian classification with longitudinal markers

Summary.  We analyse data from a study involving 173 pregnant women. The data are observed values of the β human chorionic gonadotropin hormone measured during the first 80 days of gestational age, including from one up to six longitudinal responses for each woman. The main objective in this study is to predict normal versus abnormal pregnancy outcomes from data that are available at the early stages of pregnancy. We achieve the desired classification with a semiparametric hierarchical model. Specifically, we consider a Dirichlet process mixture prior for the distribution of the random effects in each group. The unknown random-effects distributions are allowed to vary across groups but are made dependent by using a design vector to select different features of a single underlying random probability measure. The resulting model is an extension of the dependent Dirichlet process model, with an additional probability model for group classification. The model is shown to perform better than an alternative model which is based on independent Dirichlet processes for the groups. Relevant posterior distributions are summarized by using Markov chain Monte Carlo methods.     

Lower posterior death probabilities from a quick medical response in road traffic accidents

Introduction: We use data from Spain on roads and motorways traffic accidents in May 2004 to quantify the statistical association between quick medical response time and mortality rate. Method: Probit and logit parameters are estimated by a Bayesian method in which samples from the posterior densities are obtained through an MCMC simulation scheme. We provide posterior credible intervals and posterior partial effects of a quick medical response at several time levels over which we express our prior beliefs. Results: A reduction of 5 min, from a 25-min response-time level, is associated with lower posterior probabilities of death in roads and motorways accidents of 24% and 30%, respectively.     

Hypothesis test for paired samples in the presence of missing data

Missing data are present in almost all statistical analysis. In simple paired design tests, when some subject has one of the involved variables missing in the so-called partially overlapping samples scheme, it is usually discarded for the analysis. The lack of consistency between the information reported in the univariate and multivariate analysis is, perhaps, the main consequence. Although the randomness on the missing mechanism (missingness completely at random) is an usual and needed assumption for this particular situation, missing data presence could lead to serious inconsistencies on the reported conclusions. In this paper, the authors develop a simple and direct procedure which allows using the whole available information in order to perform paired tests. In particular, the proposed methodology is applied to check the equality among the means from two paired samples. In addition, the use of two different resampling techniques is also explored. Finally, real-world data are analysed.