Resilience-as-process: Negative affect, stress, and coupled dynamical systems.

Resilience is often considered both a trait and a process. The current study proposes a new way to conceptualize resilience-as-process based on dynamical systems modeling, which allows researchers to capture the process of stress management in real time. Coupled damped linear oscillator models succinctly describe daily stress and negative affect in terms of developmental forces (e.g., velocity, acceleration). Models were fit to 56-day daily response data from 42 aging adults (Mage = 78.8 years; SDage = 6.6 years) to observe and understand linkages between daily stress and affect. It was speculated that individuals with greater resilience would experience stress as less coupled to changes in negative affect (less stress reactivity), and would recover their affective equilibrium more quickly following a given exogenous stressor (greater stress recovery). To identify resilience resources related to reliable interindividual differences in coupling and damping between stress and negative affect, we examined possible protective factors. Aspects of personality and social support predicted both the strength and nature of this coupling, such that higher levels of these resources resulted in greater protection from the cost to negative affect from stress, as observed in damping of negative affect and decreased coupling between systems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Analysis of T-DNA-mediated translational beta-glucuronidase gene fusions

Using polymerase chain reaction (PCR) with back-to-back primers, 85 different mitochondrial DNA (mtDNA) rearrangements, consisting of partial duplications or mini-circles, were detected in brain, liver, and heart tissue from Fischer 344 rats. The regions around the mitochondrial tRNALeu(UUR) gene, the cluster of three tRNA genes [His, Ser(AGY), Leu(UUC)], as well as the region of the displacement loop were analyzed separately with different primer sets. Rearrangements were detected in all regions analyzed in samples taken throughout the animal life span, ranging from 1 day old to 33 months of age (senescent). Two-thirds of the rearrangements terminated at short (3-9-bp) direct repeats. Three of the different rearrangements were detected in more than one animal; the most common rearrangement was found in nine different template preparations. Two loci (hot spots) were found to be particularly susceptible to rearrangement, and both were located at sequences that exhibited highly conserved potential for secondary structure formation. The displacement loop region of 10 samples exhibited the presence of multiple tandem duplications ranging between 324 and 449 bp in length. One of these consisted of heterologous, but overlapping, repeating units. Identical PCR protocols were carried out in control experiments using a cloned fragment of mtDNA that encompassed the most common hot spot sequence. The results showed that this fragment did not artifactually generate a rearrangement junction under our PCR conditions and suggested that this sequence does not promote rearrangement mutations in bacteria during the cloning process.     

Maternal depressive symptomatology and child behavior: Transactional relationship with simultaneous bidirectional coupling.

The present study investigated reciprocal relationships between adolescent mothers and their children's well-being through an analysis of the coupling relationship of mothers' depressive symptomatology and children's internalizing and externalizing behaviors. Unlike studies using discrete time analyses, the present study used dynamical systems to model time continuously, which allowed for the study of dynamic, transactional effects between members of each dyad. Findings provided evidence of coupling between maternal depressive symptoms and children's behaviors. The most robust finding was that as maternal depressive symptoms became more or less severe, children's behavior problems increased or decreased in a reciprocal manner. Results from this study extended upon theoretical contributions of such authors as Richters (1997) and Granic and Hollenstein (2003), providing empirical validation from a longitudinal study for understanding the ongoing, dynamic relationships between at-risk mothers and their children. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Using derivative estimates to describe intraindividual variability at multiple time scales.

The study of intraindividual variability is central to the study of individuals in psychology. Previous research has related the variance observed in repeated measurements (time series) of individuals to traitlike measures that are logically related. Intraindividual measures, such as intraindividual standard deviation or the coefficient of variation, are likely to be incomplete representations of intraindividual variability. This article shows that the study of intraindividual variability can be made more productive by examining variability of interest at specific time scales, rather than considering the variability of entire time series. Furthermore, examination of variance in observed scores may not be sufficient, because these neglect the time scale dependent relationships between observations. The current article outlines a method of using estimated derivatives to examine intraindividual variability through estimates of the variance and other distributional properties at multiple time scales. In doing so, this article encourages more nuanced discussion about intraindividual variability and highlights that variability and variance are not equivalent. An example with simulated data and an example relating variability in daily measures of negative affect to neuroticism are provided. (PsycINFO Database Record (c) 2010 APA, all rights reserved)