Surface effect on the screw dislocation mobility over the Peierls barrier

The effect of the image force on the Peierls stress (τ _p ) of a screw dislocation below a free surface is studied via a self-consistent semidiscrete variational Peierls–Nabarro model. The consequence of reduction in elastic energy and increase in stacking fault energy by the presence of the free surface is found to additively increase the Peierls stress (τ _p ). This model gives a physical interpretation of the same tend observed in a recent molecular dynamic study, while previous continuum analysis predicted the opposite.     

High-temperature creep associated with the climb of extended dislocations subjected to chemical stresses

The effect of chemical stresses upon the relation between extended dislocations and high-temperature creep in a thin plate has been investigated. The critical stress needed for the contraction of extended jogs and its effect on the creep rate are obtained. The results indicate that the critical stress needed for the contraction increases with decreasing stacking fault energy (SFE). However, creep occurs more easily with increasing SFE and increasing angle of the Burgers vector to the dislocation line, as well as with the concentration of any diffusing atoms.     

Adolescent Depression: Stressful Interpersonal Contexts and Risk for Recurrence

ABSTRACT— High rates of diagnosable depression in adolescence, especially among young women, present challenging clinical and research issues. Depression not only portends current maladjustment but may also signal risk for recurrent or chronic depression and its associated impairment. Because depression is most often a response to stressful events and circumstances, it is important to understand the stress context itself. Individuals with depression histories are known to contribute to the occurrence of interpersonal and other stressors at a high rate, and for young women particularly, the occurrence of interpersonal stressors and conditions in turn predicts recurrences of depression, in a vicious cycle. Interpersonal dysfunction in early adolescence predicts the likelihood of continuing maladaptive functioning in peer, family, romantic, and parenting roles. The transmission of depression from one generation to the next involves not only heritable factors but also the likelihood that depressed youth become caught in life contexts of marital and parenting discord that portend dysfunction for their offspring and continuing depression for themselves.     

Why Does Frustration Predict Psychopathology? Multiple Prospective Pathways Over Adolescence: A TRAILS Study

Adolescents' temperamental frustration is a developmental precursor of adult neuroticism and psychopathology. Because the mechanisms that underlie the prospective association between adolescents' high frustration and psychopathology (internalizing/externalizing) have not been studied extensively, we quantified three pathways: stress generation [mediation via selection/evocation of stressful life events (SLEs)], cross‐sectional frustration‐psychopathology overlap (‘carry‐over’/common causes), and a direct (non‐mediated) vulnerability effect of frustration, including moderation of SLE impact. Frustration and psychopathology were assessed at age 16 with the Early Adolescent Temperament Questionnaire and the Youth Self‐Report. No gender differences in frustration were observed. At age 19, psychopathology was reassessed by using the Adult Self‐Report, while occurrence of endogenous (self‐generated) and exogenous (not self‐generated) SLEs during the interval (ages 16–19) were ascertained with the Life Stress Interview, an investigator‐based contextual‐stressfulness rating procedure (N = 957). Half of the prospective effect of frustration on psychopathology was explained by baseline overlap, including effects of ‘carry‐over’ and common causes, about 5% reflected stress generation (a ‘vicious’ cycle with the environment adolescents navigate and shape), and 45% reflected unmediated association: a direct vulnerability effect including stress sensitivity or moderation of SLE impact. After adjustment for their overlap, frustration predicted the development of externalizing but not internalizing symptoms. Copyright © 2016 European Association of Personality Psychology     

Interpersonal predictors of stress generation: Is there a super factor?

Hammen's (1991, Journal of Abnormal Psychology, 100, 555–561) seminal paper on stress generation highlighted the reciprocal relationship between stress and depression. Not only does stress predict depression, but women with a diagnosis of depression also experienced subsequent increased levels of stress. In the ensuing years, depression researchers have moved beyond clinical predictors and examined whether depression vulnerability factors also contribute to stress generation. This interest has led to a growing focus on interpersonal vulnerability factors that contribute to stress generation. To date, the research examining interpersonal predictors of stress generation has tended to examine vulnerability factors singly and thus potential overlap and unique predictions among vulnerability factors have not been determined. This study examines interpersonal vulnerability factors from various schools of thought (dependency, attachment, and unmitigated communion) as predictors of interpersonal stress generation. Three hundred and sixty-four young adults completed baseline measures of interpersonal vulnerabilities and provided weekly reports of depressive symptoms and stressful life events. Multilevel models were estimated to examine their unique predictions of interpersonal stress generation. Despite converging theories, there does not appear to be a single super factor. Of the interpersonal vulnerability factors tested, anxious attachment emerged as a consistent predictor of interpersonal stress generation both when examined singly and when in combination with related variables.     

Impulsivity and Behavior-Dependent Life Events Mediate the Relationship of Reward Sensitivity and Depression,but Not Hypomania,Among at-Risk Adolescents

Both reward sensitivity and impulsivity are related to the development and course of bipolar spectrum disorders (BSDs) and have been implicated in other disorders and negative functional outcomes such as substance abuse, obesity, suicidal behaviors, and risk-taking. Furthermore, according to the transactional component of the Behavioral Approach System (BAS)/reward hypersensitivity theory of BSDs, people with reward hypersensitivity should experience more BAS-relevant events, and thus, are more vulnerable to mood symptoms and episodes via stress generation. Impulsivity may exacerbate stress generation in individuals at risk for BSDs based on exhibiting reward hypersensitivity. The current study examined whether impulsivity explained the generation of stress and subsequent mood symptoms beyond what is explained by reward sensitivity alone. Participants were 131 Moderate BAS and 216 High BAS sensitivity adolescents (M = 18.43 years, SD = 1.40), who completed baseline measures of reward sensitivity and impulsivity, as well as follow-up measures of life events and mood symptoms. Results from linear regression analyses indicated that higher baseline impulsivity predicted behavior-dependent, but not behavior-independent, life events. Furthermore, path analyses suggested that the effect of BAS group on depression symptoms at next follow-up was partly explained via the indirect effect of impulsivity and negative behavior-dependent life events. We did not find these effects for behavior-independent or positive-dependent events or for prediction of hypomanic symptoms. The findings suggest that impulsivity may account for stress generation of negative events that precede depression.     

A longitudinal analysis of self-regulation and well-being: avoidance personal goals, avoidance coping, stress generation, and subjective well-being

We conducted 2 longitudinal meditational studies to test an integrative model of goals, stress and coping, and well-being. Study 1 documented avoidance personal goals as an antecedent of life stressors and life stressors as a partial mediator of the relation between avoidance goals and longitudinal change in subjective well-being (SWB). Study 2 fully replicated Study 1 and likewise validated avoidance goals as an antecedent of avoidance coping and avoidance coping as a partial mediator of the relation between avoidance goals and longitudinal change in SWB. It also showed that avoidance coping partially mediates the link between avoidance goals and life stressors and validated a sequential meditational model involving both avoidance coping and life stressors. The aforementioned results held when controlling for social desirability, basic traits, and general motivational dispositions. The findings are discussed with regard to the integration of various strands of research on self-regulation.