Minimax properties of beta kernel estimators

In this paper, we are interested in the study of beta kernel density estimators from an asymptotic minimax point of view. These estimators allows to estimate density functions with support in [0,1]. It is well-known that beta kernel estimators are - on the contrary of classical kernel estimators - “free of boundary effect” and thus are very useful in practice. The goal of this paper is to prove that there is a price to pay: for very regular density functions or for certain losses, these estimators are not minimax. Nevertheless they are minimax for classical regularities such as regularity of order two or less than two, supposed commonly in the practice and for some classical losses.     

Analysis of organizational conditions for risk management: the case study of a petrochemical site

This paper presents an ergonomic intervention in the petrochemical sector. The scheduled shutdown of one of the gas production sites has led the management to reduce the number of personnel on site, and then to get new recruits and experienced technicians from other sites as the policy for leaving personnel had not been properly planned, resulting in understaffing on site. Workers with seniority on the site, and who are also the most experienced do not accept the way newcomers are induced on site, whereas the management accuses them of resisting change. The intervention consisted in reconnecting local and corporate management through making the work activity visible and linking two sets of data that they held separately. Different types of analyses were made, work demography, decision making processes and tools used by the management, analysis of the building of career and work logics. Those different levels of analysis are gathered in macro-ergonomics, while showing the possible combinations between top down and bottom up approaches. The intervention resulted in concrete changes: HR simulation tool, training organisation, feedback.     

A Wavelet Method for Confidence Intervals in the Density Model

Abstract.  We present a wavelet procedure for defining confidence intervals for f ( x ₀), where x ₀ is a given point and f is an unknown density from which there are independent observations. We use an undersmoothing method which is shown to be near optimal (up to a logarithmic term) in a first order sense. We propose a second order correction using the Edgeworth expansion. The adaptation with respect to the unknown regularity of f is given via a Lepskii type algorithm and has the advantage to be well located. The theoretical results are proved under weak assumptions and concern very irregular or oscillating functions. An empirical study gives some hints for choosing the constant of the threshold level. The results are very encouraging for the length of the intervals as well as for the coverage accuracy.     

Attachment Representations and Discipline in Mothers of Young School Children: An Observation Study

Previous research was extended by connecting maternal attachment representations not only to maternal emotional support and task structuring, but also to maternal discipline. A total number of 62 mothers of preschoolers (M_age = 54 months) completed the adult attachment interview and a self‐report measure of dysfunctional discipline. Two years later, a subsample of 38 mother–child dyads was observed during two laboratory interaction tasks in which the mother and child were induced to have divergent goals. In general, the hypothesized connections between maternal attachment representations and discipline were found, at least when discipline was independently observed. Specifically, as compared to autonomous mothers, non‐autonomous mothers showed more overreactivity, more psychological control and less flexibility in their discipline attempts. Also, their children were less compliant. These differences were more pronounced during a story‐eliciting task than during a block task. These findings suggest that parental behaviors in the discipline domain contribute to the explanation of the intergenerational transmission of attachment patterns.     

Gambling Problems Among Community Cocaine Users

Cocaine use is highly prevalent and a major public health problem. While some studies have reported frequent comorbidity problems among cocaine users, few studies have included evaluation of gambling problems. This study aimed to estimate the prevalence of gambling problems and compare those who were at-risk gamblers with non-problem gamblers in terms of mental health problems, substance use problems, and some risk factors (i.e. family antecedents, erroneous perceptions and coping strategies) among individuals who smoke or inject cocaine. A total of 424 smoked or injected cocaine users recruited through community-based programs in Montreal (Quebec) completed the questionnaire, including the Canadian Pathological Gambling Index, the Composite International Diagnostic Interview, the CAGE, and the Severity Dependence Scale. Of the sample, 18.4 % were considered at-risk gamblers, of whom 7.8 % had problems gambling and 10.6 % were moderate-risk gamblers. The at-risk group was more likely to have experienced a recent phobic disorder and alcohol problems than the non-problem group. A multivariate analysis showed that, compared to those who were non-problem gamblers, the at-risk ones were more likely to have lost a large sum of money when they first started gambling, believed that their luck would turn, and gambled in reaction to painful life events. These results indicate the need to include routines for screening to identify gambling problem among cocaine users.     

Jack (and Jill?) of All Trades – A Canadian Case Study of Equity in Apprenticeship Supports

In the past decade, Canadian federal and provincial governments have designed programmes to facilitate entry into trades in an attempt to stimulate economic growth. As part of these efforts, increasing attention is focusing on programmes to encourage women to enter skilled trades, while paying little attention to those trades traditionally dominated by females. In this article, we explore the gendered dimensions of apprenticeship programmes in Canada, demonstrating the ways in which gender inequality is reproduced by programmes that situate employers and women as responsible for change. In particular, using a case study, we illustrate that the gendered structure of the labour market is preserved and reproduced. While efforts have targeted women to facilitate entry into non‐traditional occupations such as electricians and plumbers, female‐dominated trades such as hairstylists remain untouched, thereby sustaining the gendered wage structure of the economy. Thus women remain segregated in low‐paying trades and receive fewer public supports when pursuing training in these segregated trades. The article argues that apprenticeship training and certification is constructed to respond to the needs of male‐dominated trades, but not the needs of female‐dominated trades. Ultimately, the public policy decisions that make up the apprenticeship training and certification system in Canada reproduce gender inequality.     

Remittances in the Republic of Georgia: Correlates, Economic Impact, and Social Capital Formation

The economic impact of remittances on migrant-sending countries has been a subject of debate in the scholarly literature on migration. We consider the topic using a household-level approach. We use a new survey, “Georgia on the Move,” to examine migrant-level, household-level, and contextual variables associated with the probability that a household in the Republic of Georgia receives remittances. We then apply propensity score matching to estimate how remittances affect particular types of household expenditures, savings, labor supply, health, and other measures of well-being. Separate analysis of the subsample of households with a migrant currently abroad distinguishes the effects of remittances from the effects of migration as such. In Georgia, remittances improve household economic well-being without, for the most part, producing the negative consequences often suggested in the literature. We find evidence for an important aspect that has not been widely discussed in prior studies: remittances foster the formation of social capital by increasing the amount of money that households give as gifts to other households.     

Changes and Continuities in the Use of Diagrams <Emphasis Type="Italic">Tu</Emphasis> in Chinese Mathematical Writings (Third Century to Fourteenth Century) [I]

This article aims at highlighting a radical change in the materiality of tu 圖 between the time when they were first mentioned in Chinese mathematical texts in the third century commentaries on Canons and the thirteenth century, from which there are abundant illustrations in treatises. Moreover, it intends to highlight that the meaning of the word tu 圖, as used in mathematical writings, greatly changed over the same time span. It argues that third century tu 圖 were material objects, cut in paper with squared-grid, and worked out in specific ways. They probably always displayed particular dimensions and only represented objects for plane geometry. Their areas, and not their points, were marked, and they were marked by characters or colors. Areas were cut into pieces and rearranged. Such is the contribution mathematical texts can offer for capturing the nature of tu for these early periods. In contrast to this, thirteenth century tu 圖 to which mathematical texts refer were included in the texts themselves and hence articulated with the discourse on the surface of the page. Moreover, the extension of what could be represented in a tu 圖 increased tremendously. However, as I show in part II of this paper, in the thirteenth century, several traditions must be distinguished, regarding the nature of tu 圖 and the way in which they were integrated into the text. Moreover, part II shows that despite this break in the nature of tu 圖, some thirteenth century mathematicians inherited ways of working with tu 圖 from earlier times. I argue that this occurred within the framework of a specific mathematical domain, that is, a given subtradition. The mathematicians operating within this framework brought into play the same markers (colors, characters) for areas and adapted the operations onto paper. However, what is most interesting is that they made use of these traditional ways of working with figures while bestowing new mathematical meanings upon them. This thus presents an interesting case of continuity and rupture within a given tradition. All these uses of figures, in their variety, are specific to China and differ from the way in which other traditions used figures in mathematics.     

Adapted Couple Therapy (ACT) for Pathological Gamblers: A Promising Avenue

The study of the effectiveness of treatment for pathological gambling constitutes a field that is still largely unexplored. To date, the models assessed primarily target the individual and include little or no involvement of the family circle. Yet, the deleterious effects of gambling on loved ones and especially spouses are well recognized. Further, the addition of a couple modality to individual treatment has been shown to be effective on many levels in the treatment of substances use disorders. This article therefore proposes a critical review of (1) the literature providing a better understanding of the complex interactions between the couple relationship and pathological gambling, (2) studies on the effects of couple therapies on gamblers and their partners. We then present the therapeutic model developed by our team of clinician-researchers in collaboration with actors from Québec clinical settings: Adapted Couple Therapy (ACT) for pathological gamblers. In the Québec context, this model will serve as a complement to an individual cognitive-behavioral treatment model that has been proven effective and is employed throughout the Canadian province. The assessment of couple therapies could reveal avenues of solutions to better assist pathological gamblers who tend to drop-out of treatment and relapse.