No description available.

The diathesis-stress model focuses on the interaction between gene polymorphisms and negative environmental conditions (i.e., stressors); however, Belsky and Pluess (2009) recently proposed an alternative to diathesis-stress: the differential susceptibility hypothesis, which states that some individuals may be predisposed to be more adversely affected by negative environments but, also, to benefit more from positive environments. Nevertheless, the differential susceptibly hypothesis has not been rigorous tested. Thus, the purpose of this study was to test the differential susceptibility hypothesis by examining individual differences in men’s testosterone, behavioral, and psychological responses to social status as a function of the serotonin transporter promoter region polymorphism (5-HTTLPR), which was cited by Belsky and Pluess as a potential “plasticity gene” because one variant – the long (l) allele – appears to be associated with lower susceptibility/plasticity and another – the short allele (s) – appears to be associated with higher susceptibility/plasticity. In this study, groups of 3-4 male participants were allowed to socialize before being told that they were part of a larger initiative to create a student-run Honor Committee. They were asked to nominate one person to be the leader and one person to not be on the committee. Then, participants were told privately that everyone voted them to either (1) be the leader or (2) not be on the committee. Salivary hormone samples were collected at baseline and 20 minutes after vote feedback. In addition, after receiving the vote feedback, participants completed a series of dating anxiety and mate preference tasks and were given the option to examine an “actual honor violation” case either alone or as part of the committee. The results support the differential susceptibility hypothesis. In terms of testosterone response, ss individuals showed both greater reactivity and differential responses to vote feedback. Furthermore, the testosterone responses of ss individuals were moderated by basal cortisol, which is associated with approach/avoidance behavior (Kagan et al., 2003; Shoal, Giancola, & Kirillova, 2003). In addition, ss individuals’ decisions to work on the committee or work alone and responses to the mating tasks were dependent upon the vote feedback, whereas l-carriers’ decisions and responses were not. / text

According to differential susceptibility theory (DST), some children may be more sensitive to both positive and negative features of the environment. However, research has generated a list of widely disparate temperamental traits that may reflect differential susceptibility to the environment. In addition, findings have implicated these temperament × environment interactions in predicting a wide variety of child outcomes. This study uses a novel evolutionary model of temperament to examine whether differential susceptibility operates in a domain-general or domain-specific manner. Using a racially and socioeconomically diverse sample of 243 preschoolers and their parents (56% female; 48% African American), we examined the interactions between maternal and paternal parenting quality and two evolutionary informed temperament profiles (i.e., Hawks and Doves) in predicting changes in teacher-reported conduct problems and depressive symptoms from preschool to first grade. Results suggest that differential susceptibility operates in a domain-specific fashion. Specifically, the "Hawk" temperament was differentially susceptible to maternal parenting in predicting externalizing problems. In contrast, the "Dove" temperament was susceptible to both paternal and maternal parenting quality in predicting changes in depressive symptoms. Findings provide support for an integrative framework that synthesizes DST with an evolutionary, function-based approach to temperament.

This study examined possible interactions between DRD4 genotype and parenting on children’s externalizing, internalizing, and prosocial behaviors, and explored both parent and child perceptions of all variables. Both diathesis-stress and differential susceptibility hypotheses were assessed for examining possible interactions for children with the DRD4 7-repeat allele. Data were collected from 58 families within the Southern Illinois Twins/Triplets and Siblings Study (SITSS). Results indicated that although no gene-environment interactions were found when examining child perceptions, a significant interaction emerged between DRD4 and parenting in predicting externalizing behaviors when using parent reports. Children without the 7-repeat allele appeared to be malleable to both positive and negative parenting, supporting differential susceptibility. Also, child and parent reports of parenting were both predictive of child behavior. Lastly, MZ twins perceived more similar parenting environments than DZ twins, and there appeared to be a stronger environmental effect of parenting on externalizing after controlling for the effects of genes. This study adds to the differential susceptibility literature and points to the importance of considering perceptions of both children and parents when examining the effects of parenting on child behaviors.

Anxiety is the most commonly reported mental health problem among adolescents. Still, many adolescents in need of treatment are not detected and the clinical characteristics and etiological pathways of adolescent anxiety are under-researched topics. This thesis examined the clinical utility of the Swedish versions of the Spence Children’s Anxiety Scale (SCAS) and the clinical characteristics of multiple anxiety disorders among psychiatrically referred adolescents, and the influence of parenting and oxytocin gene (OXT) variants on anxiety among adolescents in the general population.  Studies employed cross-sectional and longitudinal designs and were based on questionnaire, interview, and genotype data. Support for the reliability and validity of both SCAS and SCAS-P was obtained. The overall ability to predict anxiety among referred adolescents ranged from fair to excellent for both scales.  Among adolescents psychiatrically referred for any reason, the prevalence of any anxiety disorder was 46%. Homotypic comorbidity was observed in 43%, and heterotypic comorbidity in 91%. Early adolescent anxiety influenced homotypic anxiety in late adolescence independent of parental rejection and control. The mediating role of parenting was small with indirect effect sizes no larger than one-tenth the size of direct effects, irrespective of the informant on parenting behavior. Significant interaction effects with positive and negative parenting were observed for OXT variants rs4813625 and rs2770378 in relation to social anxiety. The nature of the interactions was in line with the differential susceptibility framework for rs4813625, whereas for rs2770378, results indicated a diathesis–stress type of interaction. The findings suggest that psychiatrically referred adolescents with anxiety disorders are best characterized as a highly complex patient group and call attention to the necessity of structured assessment. For this purpose, this thesis provides evidence for the clinical utility of the SCAS; routine utilization of this questionnaire can improve detection of adolescents in need of anxiety treatment. Findings of this theses further suggest that the influence of positive and negative parenting behaviors on anxiety may be of greater importance among some adolescents than others, depending on individual differences in sensitivity to parenting. The etiology of anxiety among adolescents may therefore involve differential susceptibility effects of the interplay between genes and parenting behaviors.

No description available.

No description available.

Risky alcohol use increases the risk of certain crimes such as drunk driving, spousal abuse and fighting. Around 60% of an individual’s alcohol use is attributable to genetic influences, however little is known regarding the specific genes that are involved in increasing the risk of risky alcohol use. Recent theories posit that some genes are so called susceptibility genes, meaning that carriers of certain genes or alleles are more susceptible both to positive and negative environments. The aim of the present study was to examine main and interaction effects of a possible susceptibility gene (ANKK1, which in previous research has been found to be related to risky alcohol use), and victimization as a negative environmental factor and parent-child relationship as a positive factor. Data were drawn from the RESUME project, and in the present study, 1.800 participants were included (47% males; 53% females; mean age of 22.15 years). Results showed no statistically significant main or interaction effect for ANKK1, but a statistically significant main effect was found for victimization and parent-child relationship. In conclusion, future research should include a larger sample size and use participants diagnosed with alcohol dependency. In addition, the susceptibility properties of ANKKI needs to be further examined, as the results from the present study indicate that ANKK1 is not a susceptibility gene. / Riskfylld alkoholkonsumtion kan öka risken för att vissa brott begås, såsom rattfylleri, partnervåld och slagsmål. Forskning har visat att omkring 60% av en individs alkoholkonsumtion kan förklaras av genetik, men det finns lite forskning kring just vilka gener som ökar risken för alkoholism. Nya teorier tror att vissa gener är så kallade sårbarhetsgener, vilket innebära att individer som bär på dessa gener eller särskilda alleler är mer sårbara för både positiva och negativa miljöfaktorer. Syftet med den nuvarande studien var att undersöka huvud-och interaktionseffekter av en potentiell sårbarhetsgen (ANKK1, som tidigare forskning visat har en påverkan på riskfylld alkoholkonsumtion), med utsatthet som den negativa faktorn och barn-föräldrarelation som den positiva faktorn. Data i form av enkätsvar och DNA prov från RESUME studien användes för den nuvarande studien, där 1,800 deltagare inkluderades (47% män; 53% av kvinnor; medelålder = 22.15). Resultaten visade inte på någon statistiskt signifikant huvud-eller interaktionseffekt för ANKKI, men det fanns en statistiskt signifikant huvudeffekt för utsatthet och barn-föräldrarelation. Slutsatsens som dras är att framtida studier bör fokusera på att ha ett större urval och använda sig av deltagare som är diagnosticerade med alkoholmissbruk. Utöver det bör framtida forskning fortsätta undersöka om ANKK1 är en sårbarhetsgen, eftersom resultaten från denna studie visar att den inte är en sårbarhetsgen.

Quizalofop and florpyrauxifen-benzyl are both new herbicides for rice in the midsouthern U.S. Quizalofop is only effective for control of monocot weed species; therefore, mixtures of florpyrauxifen-benzyl with quizalofop could be beneficial in acetyl CoA carboxylase (ACCase)-resistant rice. Field experiments were conducted at the Delta Research and Extension Center in Stoneville, MS, in 2017 and 2018 to evaluate control of monocot and dicot weed species with sequential applications of quizalofop including auxinic herbicides in the first or second treatment. Other field experiments in 2017 and 2018 evaluated sequential applications of different rates of quizalofop with florpyrauxifen-benzyl included in treatments immediately prior to flooding. A final field experiment in 2017 and 2018 evaluated growth and yield of six ACCase-resistant rice cultivars and advanced lines following POST applications of florpyrauxifen-benzyl.

L’intérêt marqué et simultané de plusieurs champs de recherche pour le développement des fonctions exécutives (FE) a permis de mettre en lumière le rôle primordial de ces fonctions dans plusieurs sphères du développement de la petite enfance jusqu’à l’âge adulte. Les mécanismes développementaux associés aux différences individuelles restent par ailleurs encore peu étudiés. Les deux articles empiriques qui constituent la thèse visent à documenter le rôle des comportements maternels observés en bas âge dans la prédiction des FE mesurées à l’âge préscolaire. Les deux articles s’inscrivent dans la foulée des travaux qui, selon une approche écologique (Bronfenbrenner, 1979), considèrent les effets d’interaction entre différents facteurs explicatifs pour mieux comprendre les mécanismes impliqués dans le développement de l’enfant. En ce sens, le premier article examine les interactions possibles entre le statut socioéconomique (SSE) de la famille et différentes dimensions du concept de sensibilité maternelle, dans la prédiction de deux dimensions des FE, soit les FE-conflit et les FE-inhibition. Dans le cadre de cette étude, 114 dyades mères-enfants ont participé à trois visites à domicile. Le SSE a été mesuré par questionnaire dans le cadre d’une première visite dans la famille lorsque les enfants avaient six mois, la sensibilité maternelle a été évaluée à 12 mois à partir du Tri de cartes de comportements maternels (Pederson & Moran, 1995) et les FE à 36 mois à partir d’une batterie de tâches choisie sur la base des orientations proposées par Carlson (2005). Le deuxième article explore, en se basant sur postulats de la Théorie de la susceptibilité différentielle (TSD), les possibles interactions entre différentes dimensions du concept de sensibilité maternelle et le tempérament de l’enfant, et ce également dans la prédiction des FE. Pour ce faire, 72 dyades ont également participé à trois visites à domicile. La sensibilité maternelle a été évaluée à 12 mois à partir du Tri de cartes de comportements maternels (Pederson & Moran, 1995), le tempérament à 15 mois à l’aide d’un questionnaire rempli par la mère (ICQ; Bates, Freeland, & Lounsbury, 1979) et les FE à 36 mois à partir de la même batterie de tâche (Carlson, 2005). Les résultats du premier article révèlent des interactions significatives entre le statut socioéconomique et certaines dimensions de comportements maternels, de telle sorte que des comportements maternels de meilleure qualité sont prédicteurs d’une meilleure performance aux tâches de FE, mais seulement chez les enfants provenant de familles relativement désavantagées sur le plan socioéconomique et essentiellement en ce qui concerne les FE-inhibition. Quant aux résultats du deuxième article, ils confirment les hypothèses de la Théorie de la susceptibilité différentielle, en révélant que les enfants ayant un tempérament difficile sont plus affectés par des comportements maternels hostiles, de même que par l’absence de comportements positifs et bénéficient davantage de la présence de comportements positifs et de l’absence de comportements négatifs, et ceci également au regard des FE-inhibition. / The simultaneous and marked interest of many fields of research for the notion of executive functioning (EF) has allowed for the primordial role of these functions in many spheres of development to be identified. However, the developmental mechanisms associated with individual differences in EF are still under studied. The two empirical articles constituting this dissertation aim at documenting the role of maternal behaviors in the prediction of EF in the preschool period. Using an ecological approach (Bronfenbrenner, 1979), interaction effects between different explanatory factors are considered, with the goal of reaching a better understanding of the mechanisms underlying early EF development. To do so, the first article examines the interactions between family socioeconomic status (SES) and different dimensions of maternal behavior in the prediction of two specific components of EF, namely, conflict-EF and impulse control. 114 mother-child dyads participated in three home visits. SES was measured by a questionnaire filled by mothers during the first visit when their child was six months old and maternal behavior was observed in a second visit when the child was 12 months old, using the Maternal Behavior Q-Sort (MBQS; Pederson & Moran, 1995). Finally, child EF was assessed at 3 years with a battery of tasks chosen based on Carlson’s (2005) measurement guidelines. The second article explores, based on Differential Susceptibility Theory (DST), the interactions between different dimensions of maternal behavior and child temperament in the prediction of child EF. Seventy-two mother-child dyads participated in three home visits. Maternal sensitivity was observed when children were 12 months old, using the MBQS, child temperament was assessed at 15 months using a maternal report (ICQ; Bates, Freeland, & Lounsbury, 1979), and child EF was assessed with the same battery of tasks as in the first article. The results of the first article showed significant interactions between family SES and the quality of maternal behaviors in the prediction EF, such that maternal behavior was related to EF only for children in the lower end of the SES spectrum and those relations were found especially for impulse control. The results of the second article confirmed the hypothesis put forward by DST, revealing that children with difficult temperaments were more affected by hostile maternal behavior and the absence of positive behavior, and that these same children benefit more than their easier peers from the presence of positive behaviors, but only in the prediction of impulse control.