41 research outputs found

    Trajectories of peer nominated aggression: Risk status, predictors and outcomes

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    Developmental trajectories of peer-nominated aggression, risk factors at baseline, and outcomes were studied. Peer nominations of aggression were obtained annually from grades 1 to 3. Three developmental trajectories were identified: an early-onset/increasers trajectory with high levels of peer-nominated aggression at elementary school entry and increasing levels throughout follow-up; a moderate-persistent trajectory of aggression in which children were characterized by moderate levels of physical aggression at baseline; and a third trajectory with stable low levels of aggression. Children following the early-onset/increasers trajectory showed physical forms of aggression at baseline. Male gender and comorbid attention deficit/hyperactivity problems, oppositional defiant problems and poor prosocial behavior plus negative life events predicted which children would follow the early-onset/increasers trajectory of aggression. The outcomes associated with the early-onset/increaser children suggest high risk for chronically high levels of aggressive behavior. © 2005 Springer Science+Business Media, Inc

    The Development of Criminal Style in Adolescence and Young Adulthood: Separating the Lemmings from the Loners

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    Despite broad consensus that most juvenile crimes are committed with peers, many questions regarding developmental and individual differences in criminal style (i.e., co-offending vs. solo offending) remain unanswered. Using prospective 3-year longitudinal data from 937 14- to 17-year-old serious male offenders, the present study investigates whether youths tend to offend alone, in groups, or a combination of the two; whether these patterns change with age; and whether youths who engage in a particular style share distinguishing characteristics. Trajectory analyses examining criminal styles over age revealed that, while most youth evinced both types of offending, two distinct groups emerged: an increasingly solo offender trajectory (83%); and a mixed style offender trajectory (17%). Alternate analyses revealed (5.5%) exclusively solo offenders (i.e., only committed solo offenses over 3 years). There were no significant differences between groups in individuals’ reported number of friends, quality of friendships, or extraversion. However, the increasingly solo and exclusively solo offenders reported more psychosocial maturity, lower rates of anxiety, fewer psychopathic traits, less gang involvement and less self reported offending than mixed style offenders. Findings suggest that increasingly and exclusively solo offenders are not loners, as they are sometimes portrayed, and that exclusively solo offending during adolescence, while rare and previously misunderstood, may not be a risk factor in and of itself

    Genome-wide association and Meta-analysis of age at onset in Parkinson Disease

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    Background and Objectives Considerable heterogeneity exists in the literature concerning genetic determinants of the age at onset (AAO) of Parkinson disease (PD), which could be attributed to a lack of well-powered replication cohorts. The previous largest genome-wide association studies (GWAS) identified SNCA and TMEM175 loci on chromosome (Chr) 4 with a significant influence on the AAO of PD; these have not been independently replicated. This study aims to conduct a meta-analysis of GWAS of PD AAO and validate previously observed findings in worldwide populations. Methods A meta-analysis was performed on PD AAO GWAS of 30 populations of predominantly European ancestry from the Comprehensive Unbiased Risk Factor Assessment for Genetics and Environment in Parkinson's Disease (COURAGE-PD) Consortium. This was followed by combining our study with the largest publicly available European ancestry dataset compiled by the International Parkinson Disease Genomics Consortium (IPDGC). Results The COURAGE-PD Consortium included a cohort of 8,535 patients with PD (91.9%: Europeans and 9.1%: East Asians). The average AAO in the COURAGE-PD dataset was 58.9 years (SD = 11.6), with an underrepresentation of females (40.2%). The heritability estimate for AAO in COURAGE-PD was 0.083 (SE = 0.057). None of the loci reached genome-wide significance (p < 5 × 10−8). Nevertheless, the COURAGE-PD dataset confirmed the role of the previously published TMEM175 variant as a genetic determinant of the AAO of PD with Bonferroni-corrected nominal levels of significance (p < 0.025): (rs34311866: ÎČ(SE)COURAGE = 0.477(0.203), pCOURAGE = 0.0185). The subsequent meta-analysis of COURAGE-PD and IPDGC datasets (Ntotal = 25,950) led to the identification of 2 genome-wide significant association signals on Chr 4, including the previously reported SNCA locus (rs983361: ÎČ(SE)COURAGE+IPDGC = 0.720(0.122), pCOURAGE+IPDGC = 3.13 × 10−9) and a novel BST1 locus (rs4698412: ÎČ(SE)COURAGE+IPDGC = −0.526(0.096), pCOURAGE+IPDGC = 4.41 × 10−8). Discussion Our study further refines the genetic architecture of Chr 4 underlying the AAO of the PD phenotype through the identification of BST1 as a novel AAO PD locus. These findings open a new direction for the development of treatments to delay the onset of PD

    Scheduling contractors' farm-to-farm crop harvesting operations

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    The harvesting of renewable resources from an operations scheduling viewpoint is introduced, and a harvesting scenario arising in the agricultural context involving a commercial contracting enterprise that travels from farm-to-farm harvesting crops is discussed. This paper is an extension of previous work by two of the authors from the one-farm to the multi-farm case. In both cases, the duration of each operation is dependent upon the combination of constrained resources allocated to it, equipment and worker allocation is restricted, and minimum or maximum time lags on the start and completion of operations may be imposed. The present case incorporates harvesting at more than one farm and thus the sequence in which the farms are visited and the inter-farm travel times must be taken into account. We report on a harvesting scheduling model and solution procedures designed specifically for large-scale versions of the multi-farm case. The computational times experienced in solving general instances of the model of small-to-medium practical size by a commercial integer programming package are encouraging. Greedy and tabu search heuristics, which are capable of solving problems of relatively large dimensions in reasonable computational time are also included. The authors believe that the model and the solution techniques developed represent a useful addition to the farm crop contractor's tool kit
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