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To advance research from Dishion and others on associations between parenting and peer problems across childhood, we used a sample of 177 sibling pairs reared apart since birth (because of adoption of one of the siblings) to examine associations between parental hostility and children's peer problems when children were ages 7 and 9.5 years (n = 329 children). We extended conventional cross-lagged parent–peer models by incorporating child inhibitory control as an additional predictor and examining genetic contributions via birth mother psychopathology. Path models indicated a cross-lagged association from parental hostility to later peer problems. When child inhibitory control was included, birth mother internalizing symptoms were associated with poorer child inhibitory control, which was associated with more parental hostility and peer problems. The cross-lagged paths from parental hostility to peer problems were no longer significant in the full model. Multigroup analyses revealed that the path from birth mother internalizing symptoms to child inhibitory control was significantly higher for birth parent–reared children, indicating the possible contribution of passive gene–environment correlation to this association. Exploratory analyses suggested that each child's unique rearing context contributed to his or her inhibitory control and peer behavior. Implications for the development of evidence-based interventions are discussed.
Digenetic trematodes of the genus Clinostomum are cosmopolitan parasites infecting fishes, amphibians, reptiles, and snails as intermediate hosts. Despite the broad geographical distribution of this genus, debate about the number of species and how they vary in host use has persisted. To better understand patterns of infection among host species and across life stages, we used large-scale field surveys and molecular tools to examine five species of amphibians and seven species of fishes from 125 California ponds. Among the 12,360 examined hosts, infection was rare, with an overall prevalence of 1.7% in amphibians and 9.2% in fishes. Molecular evidence indicated that both groups were infected with Clinostomum marginatum. Using generalized linear mixed effects models, host species identity and host life stage had a strong influence on infection status, such that Lepomis cyanellus (green sunfish) (49.3%) and Taricha granulosa (rough skinned newt) (9.2%) supported the highest overall prevalence values, whereas adult amphibians tended to have a higher prevalence of infection relative to juveniles (13.3% and 2.5%, respectively). Experimentally, we tested the susceptibility of two amphibian hosts (Pseudacris regilla [Pacific chorus frog] and Anaxyrus boreas [western toad]) to varying levels of cercariae exposure and measured metacercariae growth over time. Pseudacris regilla was 1.3× more susceptible to infection, while infection success increased with cercariae exposure dose for both species. On average, metacarcariae size increased by 650% over 20 days. Our study highlights the importance of integrating field surveys, genetic tools, and experimental approaches to better understand the ecology of host–parasite interactions.
Maternal trauma is a complex risk factor that has been linked to adverse child outcomes, yet the mechanisms underlying this association are not well understood. This study, which included adoptive and biological families, examined the heritable and environmental mechanisms by which maternal trauma and associated depressive symptoms are linked to child internalizing and externalizing behaviors. Path analyses were used to analyze data from 541 adoptive mother–adopted child (AM–AC) dyads and 126 biological mother–biological child (BM–BC) dyads; the two family types were linked through the same biological mother. Rearing mother's trauma was associated with child internalizing and externalizing behaviors in AM–AC and BM–BC dyads, and this association was mediated by rearing mothers’ depressive symptoms, with the exception of biological child externalizing behavior, for which biological mother trauma had a direct influence only. Significant associations between maternal trauma and child behavior in dyads that share only environment (i.e., AM–AC dyads) suggest an environmental mechanism of influence for maternal trauma. Significant associations were also observed between maternal depressive symptoms and child internalizing and externalizing behavior in dyads that were only genetically related, with no shared environment (i.e., BM–AC dyads), suggesting a heritable pathway of influence via maternal depressive symptoms.
Latest Sandbian to early Katian sequences across Laurentia's epicontinental sea exhibit a transition from lithologies characterized as ‘warm-water’ carbonates to those characterized as ‘cool-water'carbonates. This shift occurs across the regionally recognized M4/M5 sequence stratigraphic boundary and has been attributed to climatic cooling and glaciation, basin reorganization and upwelling of open ocean water, and/or increased water turbidity and terrigenous input associated with the Taconic tectophase. Documentation of oxygen isotopic trends across the M4/M5 and through bracketing strata provides a potential means of distinguishing among these alternative scenarios; however, oxygen isotopic records generated to date have failed to settle the debate. This lack of resolution is because δ18O records are open to multiple interpretations and potentially confounding factors related to local environmental conditions have not been tested by examining the critical interval in multiple areas and different depositional settings. To begin to address this shortcoming, we present new species-specific and mixed assemblage conodont δ18O values in samples spanning the M4/M5 boundary from the Upper Mississippi Valley, Alabama, and Virginia. The new results are combined with previous studies, providing a record of δ18O variability across SE Laurentia. The combined dataset allows us to test for regional trends at a resolution not previously available. Our results document a ~1.5‰ decrease in values across Laurentia instead of increasing δ18O values across the M4/M5 as predicted in various ‘cool-water’ scenarios. In short, these results do not support a shift to ‘cool-water’ conditions as an explanation for changes in early Katian carbonates across the M4/M5.
In a longitudinal study including 642 healthy 8–11-year-old Danish children, we investigated associations between vitamin D dependent SNP and serum 25-hydroxyvitamin D (25(OH)D) concentrations across a school year (August–June). Serum 25(OH)D was measured three times for every child, which approximated measurements in three seasons (autumn, winter, spring). Dietary and supplement intake, physical activity, BMI and parathyroid hormone were likewise measured at each time point. In all, eleven SNP in four vitamin D-related genes: Cytochrome P450 subfamily IIR1 (CYP2R1); 7-dehydrocholesterol reductase/nicotinamide adenine dinucleotide synthetase-1(DHCR7/NADSYN1); group-specific complement (GC); and vitamin D receptor were genotyped. We found minor alleles of CYP2R1 rs10500804, and of GC rs4588 and rs7041 to be associated with lower serum 25(OH)D concentrations across the three seasons (all P<0·01), with estimated 25(OH)D differences of −5·8 to −10·6 nmol/l from major to minor alleles homozygosity. In contrast, minor alleles homozygosity of rs10741657 and rs1562902 in CYP2R1 was associated with higher serum 25(OH)D concentrations compared with major alleles homozygosity (all P<0·001). Interestingly, the association between season and serum 25(OH)D concentrations was modified by GC rs7041 (Pinteraction=0·044), observed as absence of increase in serum 25(OH)D from winter to spring among children with minor alleles homozygous genotypes compared with the two other genotypes of rs7041 (P<0·001). Our results suggest that common genetic variants are associated with lower serum 25(OH)D concentrations across a school year. Potentially due to modified serum 25(OH)D response to UVB sunlight exposure. Further confirmation and paediatric studies investigating vitamin D-related health outcomes of these genotypic differences are needed.
This study examined the transactional interplay among dimensions of destructive interparental conflict (i.e., hostility and dysphoria), children's emotional insecurity, and their psychological problems from middle childhood and adolescence. Participants were 232 families, with the first of five measurement occasions occurring when children were in first grade (M age = 7 years). Cross-lagged, autoregressive models were conducted with a multiple-method, multiple-informant measurement approach to identify developmental cascades of interparental and child cascades. Results indicated that emotional insecurity was a particularly powerful mediator of prospective associations between interparental conflict (i.e., dysphoria and hostility) and child adjustment during adolescence rather than childhood. In reflecting bidirectionality in relationships between interparental and child functioning, children's psychological problems predicted increases in interparental dysphoria during childhood and adolescence. Although emotional insecurity was not identified as a proximal predictor of interparental difficulties, an indirect cascade was identified whereby insecurity in early adolescence was associated with increases in teen psychological problems, which in turn predicted greater interparental dysphoria over time. Results are interpreted in the context of how they advance transactional formulation of emotional security theory and its resulting translational implications for clinical initiatives.
Child conduct problems (CP) reflect a heterogeneous collection of oppositional, aggressive, norm-violating, and sometimes violent behaviors, whereas child callous–unemotional (CU) behaviors reflect interpersonal styles of interactions reflecting a lack of guilt and empathy as well as uncaring and shallow emotional responses to others. Taken together, high levels of child CP and CU behaviors are thought to identify a relatively homogenous group of children at elevated risk for persistent and more severe problem behaviors across childhood and into adulthood. Although a large body of research has examined the developmental etiology of CP behaviors, only recently has a developmental psychopathology approach been applied to early CU behaviors. The current study examines multiple levels of contextual influences during the first years of life, including family socioeconomic status, household chaos, and parenting behaviors, on CP and CU behaviors assessed during the first-grade year. Whereas previous studies found associations between parenting behaviors and child problem behaviors moderated by household chaos, the current study found no evidence of moderation. However, path analyses suggest that the associations between child CP and CU behaviors and the contextual variables of socioeconomic status (family income and parental education) and household chaos (disorganization and instability) were mediated by maternal sensitive and harsh–intrusive parenting behavior. Analyses are presented, interpreted, and discussed with respect to both bioecological and family stress models of development.
Early identification of problems with psychosocial stress regulation is important for supporting mental and physical health. However, we currently lack knowledge about when reliable individual differences in stress-responsive physiology emerge and which aspects of maternal behavior determine the unfolding of infants' stress responses. Knowledge of these processes is further limited by analytic approaches that do not account for multiple levels of within- and between-family effects. In a low-risk sample (n = 100 dyads), we observed infant cortisol and mother/infant behavior during regular play and stress sessions longitudinally from age 1 to 3, and used a three-level model to separately examine variability in infant cortisol trajectories within sessions, across years, and across infants. Stable individual differences in hypothalamus–pituitary–adrenal axis regulation were observed in the first 3 years of life. Infants of less sensitive and more intrusive mothers manifested stress sensitization, that is, elevated cortisol levels during and following stress exposure, a profile related to behavioral distress. These findings have important practical implications, suggesting that children at risk for long-term stress dysregulation may be identified in the earliest years of life.
Mesotrione, a 4-hydroxyphenylpyruvate dioxygenase-inhibiting herbicide, is labeled for PRE and POST crabgrass control. It has enhanced efficacy on smooth and large crabgrass when applied in conjunction with soil-applied nitrogen (N). The objectives of this study, using crabgrass as the weed species, were to (1) determine the influence of N rate and tissue N concentration on mesotrione activity, (2) determine the influence of N source on mesotrione activity, and (3) determine the influence of N application timing on mesotrione activity. Large crabgrass plants that received 12 kg N ha−1 or more before mesotrione application had more bleached and necrotic leaves compared with plants that received 0 kg N ha−1 7 d after treatment (DAT) in the greenhouse. Although N application rates as high as 98 kg N ha−1 were tested, 90% leaf bleaching and necrosis were observed with rates of 8.9 or 10.1 kg N ha−1 in Tennessee and Indiana, respectively. Nitrogen concentration in large crabgrass leaf and stem tissue on the day of the mesotrione application was closely related to the bleaching and necrosis symptoms observed 7 DAT. Although N rate influenced mesotrione activity, N source did not. Nitrogen application timing was also important, with N applications 3, 1, and 0 d before a mesotrione application having the highest percentage of bleached and necrotic leaves in greenhouse experiments. Both greenhouse and field trials support the finding that N applications in proximity to the mesotrione application enhance herbicide activity. Thus, practitioners can pair N and POST mesotrione applications together or in proximity to enhance crabgrass control.
Past research has identified maternal depression and family of origin maltreatment as precursors to adolescent depression and antisocial behavior. Caregiving experiences have been identified as a factor that may ameliorate or accentuate adolescent psychopathology trajectories. Using a multilevel approach that pools the unique attributes of two geographically diverse, yet complementary, longitudinal research designs, the present study examined the role of maternal caregiver involvement as a factor that promotes resilience-based trajectories related to depressive symptoms and antisocial behaviors among adolescent girls. The first sample comprises a group of US-based adolescent girls in foster care (n = 100; mean age = 11.50 years), each of whom had a history of childhood maltreatment and removal from their biological parent(s). The second sample comprises a group of UK-based adolescent girls at high familial risk for depression (n = 145; mean age = 11.70 years), with all girls having biological mothers who experienced recurrent depression. Analyses examined the role of maternal caregiving on girls' trajectories of depression and antisocial behavior, while controlling for levels of co-occurring psychopathology at each time point. Results suggest increasing levels of depressive symptoms for girls at familial risk for depression but decreasing levels of depression for girls in foster care. Foster girls' antisocial behavior also decreased over time. Maternal caregiver involvement was differentially related to intercept and slope parameters in both samples. Results are discussed with respect to the benefits of applying multilevel (multisample, multiple outcome) approaches to identifying family-level factors that can reduce negative developmental outcomes in high-risk youth.
We present a deterministic approach to the ptychographic retrieval of the wave at the exit surface of a specimen of condensed matter illuminated by X-rays. The method is based on the solution of an overdetermined set of linear equations, and is robust to measurement noise. The set of linear equations is efficiently solved using the conjugate gradient least-squares method implemented using fast Fourier transforms. The method is demonstrated using a data set obtained from a gold–chromium nanostructured test object. It is shown that the transmission function retrieved by this linear method is quantitatively comparable with established methods of ptychography, with a large decrease in computational time, and is thus a good candidate for real-time reconstruction.