Generating a smallest binary tree by proper selection of the longest edges to bisect in a unit simplex refinement

In several areas like global optimization using branch-and-bound methods for mixture design, the unit n-simplex is refined by longest edge bisection (LEB). This process provides a binary search tree. For \(n>2\), simplices appearing during the refinement process can have more than one longest edge (LE). The size of the resulting binary tree depends on the specific sequence of bisected longest edges. The questions are how to calculate the size of one of the smallest binary trees generated by LEB and how to find the corresponding sequence of LEs to bisect, which can be represented by a set of LE indices. Algorithms answering these questions are presented here. We focus on sets of LE indices that are repeated at a level of the binary tree. A set of LEs was presented in Aparicio et al. (Informatica 26(1):17–32, 2015), for \(n=3\). An additional question is whether this set is the best one under the so-called \(m_k\)-valid condition.     

A copula-based Markov chain model for the analysis of binary longitudinal data

A fully parametric first-order autoregressive (AR(1)) model is proposed to analyse binary longitudinal data. By using a discretized version of a copula, the modelling approach allows one to construct separate models for the marginal response and for the dependence between adjacent responses. In particular, the transition model that is focused on discretizes the Gaussian copula in such a way that the marginal is a Bernoulli distribution. A probit link is used to take into account concomitant information in the behaviour of the underlying marginal distribution. Fixed and time-varying covariates can be included in the model. The method is simple and is a natural extension of the AR(1) model for Gaussian series. Since the approach put forward is likelihood-based, it allows interpretations and inferences to be made that are not possible with semi-parametric approaches such as those based on generalized estimating equations. Data from a study designed to reduce the exposure of children to the sun are used to illustrate the methods.     

Bayesian robustness of the compound Poisson distribution under bidimensional prior: an application to the collective risk model

The distribution of the aggregate claims in one year plays an important role in Actuarial Statistics for computing, for example, insurance premiums when both the number and size of the claims must be implemented into the model. When the number of claims follows a Poisson distribution the aggregated distribution is called the compound Poisson distribution. In this article we assume that the claim size follows an exponential distribution and later we make an extensive study of this model by assuming a bidimensional prior distribution for the parameters of the Poisson and exponential distribution with marginal gamma. This study carries us to obtain expressions for net premiums, marginal and posterior distributions in terms of some well-known special functions used in statistics. Later, a Bayesian robustness study of this model is made. Bayesian robustness on bidimensional models was deeply treated in the 1990s, producing numerous results, but few applications dealing with this problem can be found in the literature.     

Life Domain Satisfaction: A Portugal–France Comparison

The study was aimed at replicating on a Portuguese sample the seven-factor model of life appraisal (physical autonomy, love life, family life, social life, occupational life, finances, and leisure life) that was suggested by Salvatore and Munoz Sastre Social Indicators Research 53:229–255 (2001). A sample of 1,111 Portuguese participants, aged 17–85, was presented with the Appraisal of Life Questionnaire. The “domain” model of life appraisal satisfactorily accounted for the data gathered on the Portuguese sample. Regarding finances and occupational life, Portuguese scores were lower than French scores. Regarding the occupational score and the leisure score, a clear linear decrease as a function of age was evidenced in the Portuguese sample. Finally, regarding the family score and the financial score, a non-linear relationship with age was found. An increase was observed from young adult age to adult age, and a decrease was observed from adult age to older age. A strong decrease in the physical autonomy scores among Portuguese females was also observed.     

Toward a multi‐ethnic public sphere? Media consumption in highly diverse districts in Spain

This article examines media consumption in highly diverse districts in Spain as representative of recent changes in this field due to new immigration to countries in Southern Europe in times of crisis. Drawing on findings from two surveys, we observed a decrease in access to media specifically aimed at audiences of minority cultures between 2010 and 2012. It is suggested that this decline is not due to a modification in media consumption habits by minority groups, but rather the economic crisis of 2008. Furthermore, we study the consumption of minority media by natives: we observe that youth and more educated individuals consume other cultures’ minority media to a greater extent, particularly the press, radio, and Internet news sources. We suggest that elements are present that public administrations could utilize to further develop a multi‐ethnic public sphere. Finally, we explore the emergence of a new transnational dimension to the multi‐ethnic public sphere.     

PEER PRESSURE: EXPERIMENTAL EVIDENCE FROM RESTROOM BEHAVIOR

We provide experimental evidence on the effect of peer pressure on individual behavior. Specifically, we study the effect of being exposed to an observer in a public restroom on handwashing and urinal flushing behavior. Our estimates show that being exposed to an observer increases the probability of handwashing by 13 percentage points and the probability of urinal flushing by 15 percentage points. Given that handwashing and urinal flushing have social benefits that exceed individual benefits, our findings provide support for peer pressure as an additional way of addressing the social suboptimality arising from externalities. (JEL C91, C93)     

Perceptions of grandparents who provide auxiliary care: value transmission and child‐rearing practices

A grounded theory qualitative study was developed to explore how grandparents perceive their role as socializing agents. Forty‐two grandparents with grandchildren aged from 6 to 12 years old participated in this study. Data were collected through focus groups, which were conducted until reaching data saturation and analyzed using the constant comparative method. Four general conclusions emerged from the study: (i) grandparents recognized the importance of getting involved in the socialization of grandchildren as supporters of parents' socializing role, and the need to adapt to social changes; (ii) they emphasized traditional value that were perceived in decline, and combination of warmth and involvement were considered the best way to help grandchildren internalize values; (iii) interaction with grandchildren helped grandparents to feel active and useful, increased their life purpose and gave them a second chance to enjoy what they could not with their own children; and (iv) grandparents also accused burden and role ambiguity. These results show the importance of developing family policies that recognize grandparents' socializing role. Also, interventions that promote strategies that enable grandparents to perform their role more successfully and to cope with possible family conflicts should be developed.     

Racial/ethnic and socio‐economic biases in child maltreatment severity assessment in Spanish child protection services caseworkers

Evidence from several countries has shown the over‐representation of racial/ethnic minority groups in child protection services (CPS). The objective of the present study was to explore whether racial/ethnic and socio‐economic biases influence Spanish CPS caseworkers' judgements of the severity of child maltreatment. Moreover, the study attempted to explore the influence on these judgements of the use of structured instruments and professional experience. Two case vignettes of child maltreatment were presented to 405 CPS caseworkers and 169 students of social work and psychology. Family ethnic origin and income were manipulated in the vignettes. The findings showed no statistical evidence of biases related to family ethnic origin or socio‐economic status (SES) in Spanish CPS caseworkers' judgements of maltreatment severity. Biases related to family SES were found for students for the vignettes of physical abuse. CPS caseworkers and students who did not use a structured instrument to assess maltreatment severity tended to underestimate the severity for the vignettes of parental incapacity to control child/adolescent behaviour and to overestimate it for the vignettes of physical abuse. CPS caseworkers who used a structured instrument showed higher percentages of accuracy and inter‐rater agreement, supporting the relevance of structured tools in reducing potential caseworkers' biases.     

Welfare State Development,Individual Deprivations and Income Inequality: A Cross-Country Analysis in Latin America and the Caribbean

Several scholars have confirmed the role that the welfare state (WS) plays in reducing poverty, promoting equality and ensuring the common wellbeing. One of the limitations of the scholarship has been the conceptualization and operationalization of the WS and poverty as one-dimensional variables. The purpose of this paper is to examine the relationship between welfare state development, single-dimensions deprivations and income inequality in Latin America and the Caribbean, before and after controlling for demographic and cyclical factors. The WS is operationalized as a one-dimensional variable, but also taking into account its multidimensional nature. Three individual deprivations suffered by people on poverty and two income inequality indicators are used as dependent variables. Three pooled time-series cross-section regression analyses with panel-corrected standard errors models were carried out on 18 countries in the region around 2000, 2005 and 2010. This paper shows that the development of social-welfare programs and institutions seems to be an effective way of tackling individual deprivations suffered by people on poverty in the region. On the other hand, the WS development didn’t appear to be effective to reduce income inequality. The outcomes of welfare institutions appear to be the pivotal dimension to reduce income inequality and income deprivations in the region.     

Skills Heterogeneity Among Graduate Workers: Real and Apparent Overeducation in the Spanish Labor Market

This paper takes account of skills heterogeneity among workers with a higher education degree and proposes a new measure to differentiate between real and apparent overeducation based on the level of cognitive skills actually achieved by the individuals. This proposal is applied to the study of the wage effects of overeducation in the Spanish labor market using data from PIAAC. The results suggest that between a quarter and a half of the graduate workers who appear to be overeducated in the Spanish labor market could be considered as being only apparently overeducated since they show a lower level of skills than that corresponding to their educational level or, alternatively, a level of cognitive skills which is commensurate with their job. Different returns are found for each group of overeducated individuals both when compared with adequately educated peers within a similar level of education (with greater wage penalties for apparently overeducated workers) and when the comparison is done with well-matched co-workers doing a similar job (with a wage premium for real overeducation but no significant returns for apparently overeducated workers). These different returns by skill levels beyond what overeducation measures implies that the market distinguishes between education and skills and that educational attainment per se does not perfectly align with acquired skills, meaning that traditional measures of overeducation would overstate the actual level of skills mismatch in the labor market.