Daniel P. Johnson

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Starting in adolescence and continuing through adulthood, women are twice as likely as men to experience depression. According to the response styles theory (RST), gender differences in depression result, in part, from women's tendency to ruminate more than men. A meta-analysis was performed to evaluate gender differences in rumination in adults (k = 59; N(More)
The association between stressful life events and depression has been consistently supported in the literature; however, studies of the developmental trajectories of these constructs and the nature of their association over time are limited. We examined trajectories of depressive symptoms and negative dependent life events and the associations between these(More)
Dysfunctional attitudes may be one phenotype by which genes increase risk for depression. Building on research demonstrating associations between serotonin abnormalities and dysfunctional attitudes, we examined the covariation between dysfunctional attitudes and the serotonin transporter gene-linked polymorphic region (5-HTTLPR). In a sample of nondepressed(More)
This multiwave longitudinal study tested two quantitative genetic developmental models to examine genetic and environmental influences on exposure to negative dependent and independent life events. Participants (N = 457 twin pairs) completed measures of life events annually from ages 9 to 16. The same genetic factors influenced exposure to dependent events(More)
To examine the efficacy and overall tolerability of the simultaneous initiation of treatment (coinitiation) with triiodothyronine (T3) and a selective serotonin reuptake inhibitor (SSRI) for major depressive disorder (MDD). Sources of date were Medline/Pubmed, EMBASE, the Cochrane database, and program syllabi from major psychiatric meetings held since(More)
This study examined the extent to which rumination and depression share genetic and environmental influences in a community sample of adult twins (N=663). Twins completed multiple rumination questionnaires, a depressive symptoms questionnaire and a diagnostic interview. Rumination was moderately heritable (h2=.37-.41 for the latent variable) and(More)
Scheduling of refineries is a hard hybrid problem. Application of the Constrained Envelope Scheduling (CES) approach required development of the Gradient Constraint Equation Subdivision (GCES) algorithm, a novel global feasibility solver for the large system of quadratic constraints that arise as subproblems. We describe the implemented solver and its(More)
Online debating tools enable collaboration in analysing and addressing a wide range of problems. In contexts such as e-participation in legislation, scientific inquiry or open source intelligence analysis, structured and well-formulated arguments are essential for the collaborative formation of justified viewpoints. This type of debate requires analysis of(More)
In previous work, we have presented a novel global feasibility solver for the large system of quadratic constraints that arise as subproblems in the solving of hard hybrid problems, such as the scheduling of refineries. In this paper we present the Gradient Optimal Constraint Equation Subdivision (GOCES) algorithm, which incorporates a standard NLP solver(More)
We examined the magnitude of genetic and environmental influences on observed negative emotionality at age 14, 20, and 24 months. Participants were 403 same-sex twin pairs recruited from the Longitudinal Twin Study whose emotional responses to four different situations were coded by independent raters. Negative emotionality showed significant consistency(More)