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Early life stress (ELS) is a risk factor for the development of depression in adolescence; the mediating neurobiological mechanisms, however, are unknown. In this study, we examined in early pubertal youth the associations among ELS, cortisol stress responsivity, and white matter microstructure of the uncinate fasciculus and the fornix, two key frontolimbic tracts; we also tested whether and how these variables predicted depressive symptoms in later puberty. A total of 208 participants (117 females; M age = 11.37 years; M Tanner stage = 2.03) provided data across two or more assessment modalities: ELS; salivary cortisol levels during a psychosocial stress task; diffusion magnetic resonance imaging; and depressive symptoms. In early puberty there were significant associations between higher ELS and decreased cortisol production, and between decreased cortisol production and increased fractional anisotropy in the uncinate fasciculus. Further, increased fractional anisotropy in the uncinate fasciculus predicted higher depressive symptoms in later puberty, above and beyond earlier symptoms. In post hoc analyses, we found that sex moderated several additional associations. We discuss these findings within a broader conceptual model linking ELS, emotion dysregulation, and depression across the transition through puberty, and contend that brain circuits implicated in the control of hypothalamic–pituitary–adrenal axis function should be a focus of continued research.
Gastrointestinal and mental disorders are highly comorbid, and animal models have shown that both can be caused by early adversity (e.g., parental deprivation). Interactions between the brain and bacteria that live within the gastrointestinal system (the microbiome) underlie adversity–gastrointestinal–anxiety interactions, but these links have not been investigated during human development. In this study, we utilized data from a population of 344 youth (3–18 years old) who were raised with their biological parents or were exposed to early adverse caregiving experiences (i.e., institutional or foster care followed by international adoption) to explore adversity–gastrointestinal–anxiety associations. In Study 1, we demonstrated that previous adverse care experiences were associated with increased incidence of gastrointestinal symptoms in youth. Gastrointestinal symptoms were also associated with concurrent and future anxiety (measured across 5 years), and those gastrointestinal symptoms mediated the adversity–anxiety association at Time 1. In a subsample of children who provided both stool samples and functional magnetic resonance imaging of the brain (Study 2, which was a “proof-of-principle”), adversity was associated with changes in diversity (both alpha and beta) of microbial communities, and bacteria levels (adversity-associated and adversity-independent) were correlated with prefrontal cortex activation to emotional faces. Implications of these data for supporting youth mental health are discussed.
Early institutional rearing is associated with increased risk for subsequent peer relationship difficulties, but the underlying mechanisms have not been identified. Friendship characteristics, social behaviors with peers, normed assessments of social problems, and social cue use were assessed in 142 children (mean age = 10.06, SD = 2.02; range 7–13 years), of whom 67 were previously institutionalized (PI), and 75 were raised by their biological families. Anxiety and attention-deficit/hyperactivity disorder (ADHD) symptoms, often elevated among PI children, were examined as potential mediators of PI status and baseline social functioning and longitudinal follow-ups (2 and 4 years later). Twenty-seven percent of PI children fell above the Child Behavior Checklist Social Problems cutoff. An examination of specific social behaviors with peers indicated that PI and comparison children did not differ in empathic concern or peer social approach, though parents were more likely to endorse aggression/overarousal as a reason that PI children might struggle with friendships. Comparison children outperformed PI children in computerized testing of social cue use learning. Finally, across these measures, social difficulties exhibited in the PI group were mediated by ADHD symptoms with predicted social problems assessed 4 years later. These findings show that, when PI children struggle with friendships, mechanisms involving attention and behavior regulation are likely contributors.
The focal article (Reynolds, McCauley, Tsacoumis, and the Jeanneret Symposium Participants, 2018) reviewed and discussed the challenges, practices, and opportunities for the assessment and development for senior leaders. They summarized a set of accepted wisdom for assessing senior leaders in the areas of assessment criteria, contexts, and implementation, and meanwhile, pointed out what should be explored and done in the future. One of the central premises of the focal article seems to be built on the assumption that organizations may have sufficient resources to follow the accepted wisdom to ensure the quality and effectiveness of assessment and development for senior leaders. In addition, most, if not all, of the research findings summarized and discussed in the focal article may be based on the studies under the context of established companies. Hence, whether the implications and suggestions from the focal article can generalize to small enterprises remain an open question. For example, a typical small enterprise in the United States is a company capitalized with about $25,000 (Shane, 2009). Most of these enterprises are highly centralized, have negative cash flow, and have troubles in securing cash and in obtaining customer acceptance (Rutherford & Buller, 2007). Thus, these companies may not be able to follow the accepted wisdom as recommended in the focal article. We realize that some small businesses and start-ups are extremely well funded, so our following comments apply only to those small enterprises with scarce resources.
Researchers are becoming increasingly interested in linking specific forms of early life stress (ELS) to specific neurobiological markers, including alterations in the morphology of stress-sensitive brain regions. We used a person-centered, multi-informant approach to investigate the associations of specific constellations of ELS with hippocampal and amygdala volume in a community sample of 211 9- to 13-year-old early adolescents. Further, we compared this approach to a cumulative risk model of ELS, in which ELS was quantified by the total number of stressors reported. Using latent class analysis, we identified three classes of ELS (labeled typical/low, family instability, and direct victimization) that were distinguished by experiences of family instability and victimization. Adolescents in the direct victimization class had significantly smaller hippocampal volume than did adolescents in the typical/low class; ELS classes were not significantly associated with amygdala volume. The cumulative risk model of ELS had a poorer fit than did the person-centered model; moreover, cumulative ELS was not significantly associated with hippocampal or amygdala volume. Our results underscore the utility of taking a person-centered approach to identify alterations in stress-sensitive brain regions based on constellations of ELS, and suggest victimization is specifically associated with hippocampal hypotrophy observed in early adolescence.
Early life stress (ELS) is a significant risk factor for the emergence of internalizing problems in adolescence. Beginning in adolescence, females are twice as likely as males to experience internalizing disorders. The present study was designed to examine sex differences in the association between ELS and internalizing problems in early pubertal adolescents, and whether and how corticolimbic function and connectivity may underlie these associations. Fifty-nine early pubertal males and 78 early pubertal females, ages 9–13 years (all Tanner Stage 3 or below) underwent functional magnetic resonance imaging as they performed an emotion label task that robustly interrogates corticolimbic function. Participants were also interviewed about their experience of ELS. Females exhibited a positive association between ELS and internalizing problems, whereas males exhibited no such association. Whole-brain and amygdala region of interest analyses indicated that whereas females exhibited a positive association between ELS and the ventrolateral prefrontal cortex during implicit emotion regulation, males showed no such association. Activation in these regions was positively associated with internalizing problems in females but not males; however, activation in these regions did not mediate the association between ELS and internalizing problems. Finally, both boys and girls exhibited an association between ELS and increased negative connectivity between the right ventrolateral prefrontal cortex and bilateral amygdala. Using a carefully characterized sample of early pubertal adolescents, the current study highlights important sex differences in the development of corticolimbic circuitry during a critical period of brain development. These sex differences may play a significant role in subsequent risk for internalizing problems.
The efficiency of grass nitrogen utilisation for milk production tends to be low, due partly to the slow rate of release of energy in the rumen which reduces the efficiency of capture of rapidly degradable plant proteins by the rumen microbial population. When additional sugars are infused into the rumen, microbial protein production is increased (Rooke et al., 1987). The objective of this study was to assess milk production using a grass variety that has been bred to express elevated water soluble carbohydrate (WSC) concentrations.
Eight multiparous Holstein-Friesian dairy cows in mid lactation (176 days ± s.e. 3.6) were used in a continuous design, zero-grazing experiment. Following covariate measurements taken from all animals on a standard grazing diet, four animals were each offered one of two varieties of perennial ryegrass at ad libitum rate: AberDove, bred to express high WSC concentrations; and AberElan, a commercially available variety, used as a control.
The 7 and 13-valent pneumococcal conjugate vaccines (PCVs) have reduced the incidence of invasive pneumococcal disease (IPD) in children in many countries. The objective of this work was to assess the impact of PCVs and potential herd-protection in older adults in Ireland. IPD notification and typing data from adults ⩾65 years of age from July 2007 to June 2016 was assessed using national surveillance data. There was a 94% reduction in PCV7 serotypes from 2007–2008 to 2015–2016, incidence rate ratio (IRR 0·05, P < 0·0001). However, there was no decline in the additional PCV13 (PCV13-7) serotypes over the same period (IRR 0·90) nor in comparison with the pre-PCV13 period 2009–2010 (IRR 0·92). The incidence of serotypes in the 23-valent pneumococcal polysaccharide vaccine only (PPV23-PCV13) and non-vaccine types (NVTs) increased significantly (IRR 2·17, P = 0·0002 and IRR 3·43, P = 0·0001 respectively). Consequently, the overall IPD incidence rate in adults has remained relatively unchanged (from 28·66/100 000 to 28·88/100 000, IRR 1·01, P = 0·9477). Serotype 19A and NVTs were mainly responsible for penicillin resistance in recent years. The decline of PCV7 serotypes indicate that the introduction of PCV7 resulted in herd-protection for adults. However, increases in PPV23-PCV13 and NVTs suggest that changes in vaccination strategy amongst older adults are needed to build on the success of PCVs in children.
Two disorders of attachment have been consistently identified in some young children following severe deprivation in early life: reactive attachment disorder and disinhibited social engagement disorder. However, less is known about whether signs of these disorders persist into adolescence. We examined signs of reactive attachment disorder and disinhibited social engagement disorder at age 12 years in 111 children who were abandoned at or shortly after birth and subsequently randomized to care as usual or to high-quality foster care, as well as in 50 comparison children who were never institutionalized. Consistent with expectations, those who experienced institutional care in early life had more signs of reactive attachment disorder and disinhibited social engagement disorder at age 12 years than children never institutionalized. In addition, using a conservative intent-to-treat approach, those children randomized to foster care had significantly fewer signs of reactive attachment disorder and disinhibited social engagement disorder than those randomized to care as usual. Analyses within the ever institutionalized group revealed no effects of the age of placement into foster care, but number of caregiving disruptions experienced and the percentage of the child's life spent in institutional care were significant predictors of signs of attachment disorders assessed in early adolescence. These findings indicate that adverse caregiving environments in early life have enduring effects on signs of attachment disorders, and provide further evidence that high-quality caregiving interventions are associated with reductions in both reactive attachment disorder and disinhibited social engagement disorder.
Institutional caregiving is associated with significant deviations from species-expected caregiving, altering the normative sequence of attachment formation and placing children at risk for long-term emotional difficulties. However, little is known about factors that can promote resilience following early institutional caregiving. In the current study, we investigated how adaptations in affective processing (i.e., positive valence bias) and family-level protective factors (i.e., secure parent–child relationships) moderate risk for internalizing symptoms in previously institutionalized (PI) youth. Children and adolescents with and without a history of institutional care performed a laboratory-based affective processing task and self-reported measures of parent–child relationship security. PI youth were more likely than comparison youth to show positive valence biases when interpreting ambiguous facial expressions. Both positive valence bias and parent–child relationship security moderated the association between institutional care and parent-reported internalizing symptoms, such that greater positive valence bias and more secure parent–child relationships predicted fewer symptoms in PI youth. However, when both factors were tested concurrently, parent–child relationship security more strongly moderated the link between PI status and internalizing symptoms. These findings suggest that both individual-level adaptations in affective processing and family-level factors of secure parent–child relationships may ameliorate risk for internalizing psychopathology following early institutional caregiving.
We describe the performance of the Boolardy Engineering Test Array, the prototype for the Australian Square Kilometre Array Pathfinder telescope. Boolardy Engineering Test Array is the first aperture synthesis radio telescope to use phased array feed technology, giving it the ability to electronically form up to nine dual-polarisation beams. We report the methods developed for forming and measuring the beams, and the adaptations that have been made to the traditional calibration and imaging procedures in order to allow BETA to function as a multi-beam aperture synthesis telescope. We describe the commissioning of the instrument and present details of Boolardy Engineering Test Array’s performance: sensitivity, beam characteristics, polarimetric properties, and image quality. We summarise the astronomical science that it has produced and draw lessons from operating Boolardy Engineering Test Array that will be relevant to the commissioning and operation of the final Australian Square Kilometre Array Path telescope.
A group of A-type stars in the field of the Small Magellanic Cloud (SMC) were noticed by Humphreys (1983) to have anomalously strong hydrogen (H) lines and a Balmer jump that are too strong for their luminosities. Their visual luminosities, based on membership in the SMC, are about two magnitudes brighter than one would expect from the appearance of the Balmer series. Humphreys also found that their colours are too red in U-B by 0.2 to 0.3 mag, but show little or no change in B-V relative to normal A-type supergiants; this is consistent with the strong Balmer jump in these stars' spectra. She also concluded that the objects do belong to the SMC.
Earlier, Sanduleak (1972) had identified a group of stars with similar properties in the LMC, but, because of their strong hydrogen lines, rejected them as members. However, Fehrenbach and Duflot (1972) recognized about 30 stars with A and F type spectra with unusually strong H lines. They concluded that they were members of the Large Magellanic Cloud (LMC) because of their large negative radial velocities.
Evaluating an intervention’s theoretical basis can inform design modifications to produce more effective interventions. Hence the present study’s purpose was to determine if effects from a multicomponent lifestyle intervention were mediated by changes in the psychosocial constructs decisional balance, self-efficacy and social support.
Delta Body and Soul III, conducted from August 2011 to May 2012, was a 6-month, church-based, lifestyle intervention designed to improve diet quality and increase physical activity. Primary outcomes, diet quality and aerobic and strength/flexibility physical activity, as well as psychosocial constructs, were assessed via self-report, interviewer-administered surveys at baseline and post intervention. Mediation analyses were conducted using ordinary least squares (continuous outcomes) and maximum likelihood logistic (dichotomous outcomes) regression path analysis.
Churches (five intervention and three control) were recruited from four counties in the Lower Mississippi Delta region of the USA.
Based upon results from the multiple mediation models, there was no evidence that treatment (intervention v. control) indirectly influenced changes in diet quality or physical activity through its effects on decisional balance, self-efficacy and social support. However, there was evidence for direct effects of social support for exercise on physical activity and of self-efficacy for sugar-sweetened beverages on diet quality.
Results do not support the hypothesis that the psychosocial constructs decisional balance, self-efficacy and social support were the theoretical mechanisms by which the Delta Body and Soul III intervention influenced changes in diet quality and physical activity.
Building upon the transactional model of brain development, we explore the impact of early maternal deprivation on neural development and plasticity in three neural systems: hyperactivity/impulsivity, executive function, and hypothalamic–pituitary–adrenal axis functioning across rodent, nonhuman primate, and human studies. Recognizing the complexity of early maternal–infant interactions, we limit our cross-species comparisons to data from rodent models of artificial rearing, nonhuman primate studies of peer rearing, and the relations between these two experimental approaches and human studies of children exposed to the early severe psychosocial deprivation associated with institutional care. In addition to discussing the strengths and limitations of these paradigms, we present the current state of research on the neurobiological impact of early maternal deprivation and the evidence of sensitive periods, noting methodological challenges. Integrating data across preclinical animal models and human studies, we speculate about the underlying biological mechanisms; the differential impact of deprivation due to temporal factors including onset, offset, and duration of the exposure; and the possibility and consequences of reopening of sensitive periods during adolescence.
The introduction of the Manila clam into British coastal waters in the 1980s was contested by conservation agencies. While recognizing the value of the clam for aquaculture, the government decided that it posed no invasive risk, as British sea temperatures would prevent naturalization. This proved incorrect. Here we establish the pattern of introduction and spread of the species over the first 30 years of its presence in Britain. We report archival research on the sequence of licensed introductions and examine their relationship in time and space to the appearance of wild populations as revealed in the literature and by field surveys. By 2010 the species had naturalized in at least 11 estuaries in southern England. These included estuaries with no history of licensed introduction. In these cases activities such as storage of catch before market or deliberate unlicensed introduction represent the probable mechanisms of dispersal. In any event naturalization is not an inevitable consequence of introduction and the chances of establishment over the period in question were finely balanced. Consequently in Britain the species is not currently aggressively invasive and appears not to present significant risk to indigenous diversity or ecosystem function. However it is likely to gradually continue its spread should sea surface temperatures rise as predicted.
We examined caregiver report of externalizing behavior from 12 to 54 months of age in 102 children randomized to care as usual in institutions or to newly created high-quality foster care. At baseline no differences by group or genotype in externalizing were found. However, changes in externalizing from baseline to 42 months of age were moderated by the serotonin transporter linked polymorphic region genotype and intervention group, where the slope for short–short (S/S) individuals differed as a function of intervention group. The slope for individuals carrying the long allele did not significantly differ between groups. At 54 months of age, S/S children in the foster care group had the lowest levels of externalizing behavior, while children with the S/S genotype in the care as usual group demonstrated the highest rates of externalizing behavior. No intervention group differences were found in externalizing behavior among children who carried the long allele. These findings, within a randomized controlled trial of foster care compared to continued care as usual, indicate that the serotonin transporter linked polymorphic region genotype moderates the relation between early caregiving environments to predict externalizing behavior in children exposed to early institutional care in a manner most consistent with differential susceptibility.