Depressive Symptoms and Academic Achievement: The Role of Adolescents’ Perceptions of Teachers’ and Peers’ Behaviors

This present study, using a longitudinal design, investigated how depressive symptoms are related to academic achievement and whether the perceptions of teachers’ and peers’ behaviors moderated this relation. A sample of 302 adolescents (60.10% girls, M_age = 17.35) completed scales measuring the depressive symptoms and perception of their teachers’ support/equity and peers’ cooperation/cohesiveness behaviors at Time 1. The adolescents’ average grades were also collected. The adolescents’ depressive symptoms and average grades were measured again at Time 2. The results showed that depressive symptoms measured at Time 1 were negatively associated with academic achievement measured at Time 2. The adolescents’ perception of their peers’ cooperation/cohesiveness moderated the relation between depressive symptoms and academic achievement. The results’ implications for educational practice are discussed.     

The max quasi-independent set problem

In this paper, we deal with the problem of finding quasi-independent sets in graphs. This problem is formally defined in three versions, which are shown to be polynomially equivalent. The one that looks most general, namely, f-max quasi-independent set, consists of, given a graph and a non-decreasing function f, finding a maximum size subset Q of the vertices of the graph, such that the number of edges in the induced subgraph is less than or equal to f(|Q|). For this problem, we show an exact solution method that runs within time O^*(2^{\fracd-27/23d+1n})O^{*}(2^{\frac{d-27/23}{d+1}n}) on graphs of average degree bounded by d. For the most specifically defined γ-max quasi-independent set and k-max quasi-independent set problems, several results on complexity and approximation are shown, and greedy algorithms are proposed, analyzed and tested.     

Understanding the Relationship Between Sports-Relevant Gambling and Being At-Risk for a Gambling Problem Among American Adolescents

Fantasy sports is a growing industry with a reported 56.8 million individuals participating in the United States and Canada alone in 2015. Whereas this activity has attracted considerable public attention, little research has examined its impact on adolescents in spite of their high rates of gambling. The current study examined the relationship between regular participation (more than once a month) in sport-relevant gambling activities among adolescents and those identified as being at-risk for a gambling problem. Questionnaire responses were collected from high school students (N = 6818; 49 % male) in Wood County, Ohio, United States. Statistical analyses revealed that regular involvement in sports betting, fantasy sports betting, and daily fantasy sports betting among adolescents was associated with a higher risk of gambling problems. Further, although males participate more frequently in these activities, females who participate have a stronger likelihood of being at-risk. Students aged 16–19 years old are at a higher risk for developing a gambling problem compared to younger adolescents when regularly engaging in sports-related gambling. Moreover, regularly participating in daily fantasy sports is the strongest predictor of at-risk gambling behavior in 13–15 year old students. A hierarchical logistic regression supports that controlling for gender and age, all forms of sport-relevant gambling activities are significant predictors of at-risk gambling. This study contributes to a more comprehensive understanding of the impact of sports betting and fantasy sports on adolescents and establishes an initial step for future studies to further investigate these relationships.     

On the max-weight edge coloring problem

We study the following generalization of the classical edge coloring problem: Given a weighted graph, find a partition of its edges into matchings (colors), each one of weight equal to the maximum weight of its edges, so that the total weight of the partition is minimized. We explore the frontier between polynomial and NP-hard variants of the problem, with respect to the class of the underlying graph, as well as the approximability of NP-hard variants. In particular, we present polynomial algorithms for bounded degree trees and star of chains, as well as an approximation algorithm for bipartite graphs of maximum degree at most twelve which beats the best known approximation ratios.     

Fear of childbirth in primiparous Italian pregnant women: The role of anxiety,depression, and couple adjustment

Background

The prevalence of fear of childbirth in pregnant women is described to be about 20–25%, while 6–10% of expectant mothers report a severe fear that impairs their daily activities as well as their ability to cope with labour and childbirth. Research on fear of childbirth risk factors has produced heterogeneous results while being mostly done with expectant mothers from northern Europe, northern America, and Australia.

More on the volatility-trading volume relationship in emerging markets: The Chinese stock market

This paper empirically investigates the characteristics in terms of volatility and trading volume relationships of the Chinese stock markets, and specifically of the stocks comprising the SSE180 index. Our results show that, contrary to previous evidence, both volatility and trading volume appear to be multi-fractal and highly intermittent, suggesting a common long-run behaviour in addition to the common short-term behaviour underlined by former studies. Moreover, the trading volume seems to have no explanatory power for volatility persistence when introduced in the conditional variance equation. Finally, the sign of the trading volume coefficients is mainly negative, hence showing a negative correlation between the two variables.     

What Impact Do Contextual Variables Have on the Changing Geography of Mortality in Italy?

Using data for 94 provinces, three periods (1971–1973, 1981–1983 and 1991–1993), and for men and women, we present an interesting picture of the geography of adult and elderly mortality by cause of death in Italy. This picture brings into focus the North/South gap that has yet again emerged, this time in gender differences in mortality. Particular attention is given to mortality from those causes that would appear to depend on the geographical context and that have a greater role to play in overall mortality differences. We then define which causes of death have changed the geographic pattern in the period considered. Lastly we study the relationship between mortality by cause and socio-economic, health care, environmental, cultural, and nutritional variables. This revised version was published online in July 2006 with corrections to the Cover Date.     

Exact algorithms for scheduling programs with shared tasks

We study a scheduling problem where the jobs we have to perform are composed of one or more tasks. If two jobs sharing a non-empty subset of tasks are scheduled on the same machine, then these shared tasks have to be performed only once. This kind of problem is known in the literature under the names of VM-PACKING or PAGINATION. Our objective is to schedule a set of these objects on two parallel identical machines, with the aim of minimizing the makespan. This problem is NP-complete as an extension of the PARTITION problem. In this paper we present three exact algorithms with worst-case time-complexity guarantees, by exploring different branching techniques. Our first algorithm focuses on the relation between jobs sharing one or more symbols in common, whereas the two other algorithms branches on the shared symbols.