Interplay between Friends' Aggression and Friendship Quality in the Development of Child Aggression during the Early School Years

The aim of this study was to investigate the unique and combined role of friendship quality and friends' aggression in regard to the persistence of young children's physical aggression from kindergarten to grade 2. The sample included 1555 children (808 girls) assessed annually using teacher ratings. Two theoretical perspectives (i.e., the social learning and the social bonding perspectives) served as frameworks to guide the analyses and interpret the results. In line with the social learning perspective, friends' aggression was related to a significant increase in children's physical aggression. However, in line with the social bonding perspective, good friendship quality played both a compensatory and a protective role, by, respectively, reducing children's initial level of physical aggression and by mitigating, albeit marginally, the associations between friends' and children's physical aggression. These results suggest that fostering a positive relationship between friends in the early school years may decrease physical aggression even if the friends are aggressive.     

Contagion of Anxiety Symptoms Among Adolescent Siblings: A Twin Study

This study examined whether social contagion of anxiety symptoms is present between siblings during early adolescence and whether this process is moderated by sex, relationship quality, and zygosity. Based on 634 monozygotic and dizygotic twins (336 females) assessed in Grades 6 and 7, anxiety symptoms and sibling relationship quality were measured with self‐report questionnaires. The predictive association of the co‐twin's level of anxiety with adolescents' own increased anxiety 1 year later was only observed in same‐sex twin dyads (monozygotic and dizygotic) and was higher for those who perceived a higher level of relationship quality with their co‐twin. Raising awareness of a possible sibling contagion of anxiety may be useful for preventing the development of anxiety symptoms in youth.     

Co-morbidity Between Gambling Problems and Depressive Symptoms: A Longitudinal Perspective of Risk and Protective Factors

In both adolescents and adults, gambling problems and depressive symptoms co-occur and share some common risk factors (e.g., impulsivity and socio-family risk). However, little is known about (1) the developmental course of the co-morbidity of these problems; (2) variables that may moderate the effect of these common risk factors on gambling problems and depressive symptoms. Of specific interest could be individuals’ social relationships with significant others such as parents and friends, because research shows that they moderate the effect of other risk factors on gambling problems and depressive symptoms. The goals of this study were to: (a) identify developmental pathways for gambling problems and depressive symptoms, with a focus on co-morbidity; (b) assess the moderating effect of relationship quality with parents and friends on the link between common risk factors and the trajectories of gambling problems and depressive symptoms. Study participants were 878 males. Predictors were assessed during childhood and adolescence and gambling problems and depressive symptoms were assessed in late adolescence and young adulthood. Latent class analysis revealed four distinct joint trajectories of gambling problems and depressive symptoms. Subsequent logistic regression revealed that impulsivity predicted membership in all pathogenic trajectories, and quality of the relationship with parents predicted membership in depressogenic trajectories. In addition, we found that the membership in the comorbid trajectory can be predicted by an interaction between friendship quality and socio-family risk.     

Materials receiving capacity and inventory management

This paper analyses the optimal level of materials receiving capacity for a manufacturer that receives deliveries from many suppliers. Inventory levels and inventory carrying costs depend on the frequency of deliveries and thus, on the materials receiving capacity. An analytic model that captures the tradeoff between inventory costs and materials receiving costs is presented and discussed. The receiving cost is modeled as increasing in discrete jumps of varying sizes whenever materials receiving resources are added. Practical issues in implementing the model are highlighted and methods to reduce the marginal materials receiving cost are discussed. The paper also discusses connections to the JIT approach for production environments where materials receiving is heavily automated.     

Prince George is Not (and never was) Canada’s Most Dangerous City: Using Police-Recorded Data for Comparison of Volume and Seriousness of Crimes

This article is based on the idea that crime should be analyzed in terms of both volume and seriousness. Crime rates are the most usual measure of the volume of criminality at a given time or a given place. Statistics Canada recently developed a Crime Severity Index to account for variations in the seriousness of police-recorded criminal infractions. A close look at its construction reveals that the Index is a weighted rate influenced by both the volume and the seriousness of recorded infractions. This article introduces a new indicator designed to measure the seriousness of recorded infractions. The measure is based on simple calculations and easy to interpret. It suggests that serious crime has decreased since the 1980s. It also suggests that city and province rankings based solely on crime rates are misleading because high levels of crime do not necessarily indicate high levels of the more serious crimes.     

Extremely Premature and Very Low Birthweight Infants: A Double Hazard Population?

This article evaluates the contributions of birth status (defined by gestational age and birthweight) and family adversity at birth and at age 7 to explaining behavior problems at age 7. The behaviors of 96 extremely preterm and very low birth‐weight children and 66 full‐term children were assessed in a school setting by peers, teachers and parents. The results show that a significant relationship exists between birth status and isolation and social withdrawal problems as well as between birth status and social immaturity and inattention problems. Family adversity at birth has a significant contribution to aggressive behaviors reported by the three sources whereas, at age 7, this index is associated only with aggressive behaviors and social immaturity problems reported by parents. In conclusion, the results of the present study qualify the findings of studies that suggest that at school age, the effect of prematurity decreases and that behavior problems are explained chiefly by family environment characteristics. Our results indicate that the findings must take into account the cohort studied, the environmental measures used, the type of behaviors assessed as well as the type of informants.     

Tree-structured subgroup analysis for censored survival data: Validation of computationally inexpensive model selection criteria

The performance of computationally inexpensive model selection criteria in the context of tree-structured subgroup analysis is investigated. It is shown through simulation that no single model selection criterion exhibits a uniformly superior performance over a wide range of scenarios. Therefore, a two-stage approach for model selection is proposed and shown to perform satisfactorily. Applied example of subgroup analysis is presented. Problems associated with tree-structured subgroup analysis are discussed and practical solutions are suggested.     

Relations between Theory of Mind and Indirect and Physical Aggression in Kindergarten: Evidence of the Moderating Role of Prosocial Behaviors

The present study examined the association between theory of mind and indirect versus physical aggression, as well as the potential moderating role of prosocial behavior in this context. Participants were 399 twins and singletons drawn from two longitudinal studies in Canada. At five years of age, children completed a theory of mind task and a receptive vocabulary task. A year later, teachers evaluated children's indirect and physical aggression and prosocial behavior. Indirect aggression was significantly and positively associated with theory of mind skills, but only in children with average or low levels of prosocial behavior. Physical aggression was negatively associated with prosocial behavior but not with theory of mind. Each analysis included gender, receptive vocabulary, and the respective other subtype of aggression as control variables. These results did not differ between girls and boys or between twins and singletons. Theoretical and clinical implications of these findings are discussed.     

Longitudinal Links Between Gambling Participation and Academic Performance in Youth: A Test of Four Models

Gambling participation and low academic performance are related during adolescence, but the causal mechanisms underlying this link are unclear. It is possible that gambling participation impairs academic performance. Alternatively, the link between gambling participation and low academic performance could be explained by common underlying risk factors such as impulsivity and socio-family adversity. It could also be explained by other current correlated problem behaviors such as substance use. The goal of the present study was to examine whether concurrent and longitudinal links between gambling participation and low academic performance exist from age 14 to age 17 years, net of common antecedent factors and current substance use. A convenience sample of 766 adolescents (50.6% males) from a longitudinal twin sample participated in the study. Analyses revealed significant, albeit modest, concurrent links at both ages between gambling participation and academic performance. There was also a longitudinal link between gambling participation at age 14 and academic performance at age 17, which persisted after controlling for age 12 impulsivity and socio-family adversity as well as current substance use. Gambling participation predicts a decrease in academic performance during adolescence, net of concurrent and antecedent personal and familial risk factors.     

Do Friendships and Sibling Relationships Provide Protection against Peer Victimization in a Similar Way?

Based on the notion that friendship may serve an important protective function against peer victimization, this study examined the moderating effect of reciprocal friends' prosociality on the link between a child's reactive aggression and victimization. The study also investigated whether a similar moderating effect could be found with respect to sibling's prosociality, given that sibling relationships have been found to provide social benefits comparable to friendships. These questions were addressed using a sample of 246 six‐year‐old twin pairs (246 boys and 246 girls). The results showed that a child's own reactive aggression uniquely contributed to the risk of victimization for both boys and girls. The link between reactive aggression and victimization was, however, moderated by reciprocal friends' prosocial behavior and siblings' prosocial behavior, respectively. The results are discussed in terms of their theoretical and prevention‐related implications for children at risk for peer victimization.