Automatized analysis of children's exposure to child-directed speech in reschool settings: Validation and application

The present study explored whether a tool for automatic detection and recognition of interactions and child-directed speech (CDS) in preschool classrooms could be developed, validated, and applied to non-coded video recordings representing children's classroom experiences. Using first-person video recordings collected by 13 preschool children during a morning in their classrooms, we extracted high-level audiovisual features from recordings using automatic speech recognition and computer vision services from a cloud computing provider. Using manual coding for interactions and transcriptions of CDS as reference, we trained and tested supervised classifiers and linear mappings to measure five variables of interest. We show that the supervised classifiers trained with speech activity, proximity, and high-level facial features achieve adequate accuracy in detecting interactions. Furthermore, in combination with an automatic speech recognition service, the supervised classifier achieved error rates for CDS measures that are in line with other open-source automatic decoding tools in early childhood settings. Finally, we demonstrate our tool's applicability by using it to automatically code and transcribe children's interactions and CDS exposure vertically within a classroom day (morning to afternoon) and horizontally over time (fall to winter). Developing and scaling tools for automatized capture of children's interactions with others in the preschool classroom, as well as exposure to CDS, may revolutionize scientific efforts to identify precise mechanisms that foster young children's language development.

Will I Stay Married? Exploring Predictors of Expectations to Divorce in Unmarried Young Adults

Expectations that one may eventually divorce may predict behavior in young adulthood and beyond, but studies that have looked at individuals' assessments of their divorce likelihood have been limited. Guided by the expectancy-value theory of achievement motivation, we tested five categories of potential predictors of divorce expectations in a sample of 1,610 unmarried young adults from the Panel Study of Income Dynamics Transition to Adulthood study. Predictors were tested separately by gender and partnership status. Results suggested that some predictors mattered more for some groups than others, such as employment for single men, or certainty of marriage for partnered women. Consistent with prior research, caregiver divorce was significantly associated with expectations to divorce, but was only one of many factors found to predict these expectations. Socioeconomic factors and experiences and expectations of other relationships consistently predicted expectations. Expectations to divorce are multifaceted and complex.

Parenting Gains in Head Start as a Function of Initial Parenting Skill

Using data from the Head Start Impact Study (n = 3,696), this article examines whether one year of Head Start differentially benefited parents as a function of their initial parenting behaviors. Four outcomes are examined, namely parents' rates of engaging in cognitive stimulation, reading to their child, and spanking, as well as their depressive symptoms. In general, most parents demonstrated improvements in their reading practices and cognitive stimulation, regardless of their parenting behaviors at baseline. However, depressive symptoms and spanking behavior showed improvements only among parents who began the Head Start program with the most depressive symptoms and the most frequent spanking, respectively. These findings suggest that treatment-induced changes in parenting can vary by parents' incoming attributes and that heterogeneity of effects should be considered. Implications for Head Start and other parenting interventions are discussed.

Classroom Age Composition and the School Readiness of 3- and 4-Year-Olds in the Head Start Program

The federal Head Start program, designed to improve the school readiness of children from low-income families, often serves 3- and 4-year-olds in the same classrooms. Given the developmental differences between 3- and 4-year-olds, it is unknown whether educating them together in the same classrooms benefits one group, both, or neither. Using data from the Family and Child Experiences Survey 2009 cohort, this study used a peer-effects framework to examine the associations between mixed-age classrooms and the school readiness of a nationally representative sample of newly enrolled 3-year-olds (n = 1,644) and 4-year-olds (n = 1,185) in the Head Start program. Results revealed that 4-year-olds displayed fewer gains in academic skills during the preschool year when they were enrolled in classrooms with more 3-year-olds; effect sizes corresponded to 4 to 5 months of academic development. In contrast, classroom age composition was not consistently associated with 3-year-olds' school readiness.

Activity-dependent depression of neuronal sodium channels by the general anaesthetic isoflurane

BACKGROUND

The mechanisms by which volatile anaesthetics such as isoflurane alter neuronal function are poorly understood, in particular their presynaptic mechanisms. Presynaptic voltage-gated sodium channels (Na(v)) have been implicated as a target for anaesthetic inhibition of neurotransmitter release. We hypothesize that state-dependent interactions of isoflurane with Na(v) lead to increased inhibition of Na(+) current (I(Na)) during periods of high-frequency neuronal activity.

METHODS

The electrophysiological effects of isoflurane, at concentrations equivalent to those used clinically, were measured on recombinant brain-type Na(v)1.2 expressed in ND7/23 neuroblastoma cells and on endogenous Na(v) in isolated rat neurohypophysial nerve terminals. Rate constants determined from experiments on the recombinant channel were used in a simple model of Na(v) gating.

RESULTS

At resting membrane potentials, isoflurane depressed peak I(Na) and shifted steady-state inactivation in a hyperpolarizing direction. After membrane depolarization, isoflurane accelerated entry (τ(control)=0.36 [0.03] ms compared with τ(isoflurane)=0.33 [0.05] ms, P<0.05) and slowed recovery (τ(control)=6.9 [1.1] ms compared with τ(isoflurane)=9.0 [1.9] ms, P<0.005) from apparent fast inactivation, resulting in enhanced depression of I(Na), during high-frequency stimulation of both recombinant and endogenous nerve terminal Na(v). A simple model of Na(v) gating involving stabilisation of fast inactivation, accounts for this novel form of activity-dependent block.

CONCLUSIONS

Isoflurane stabilises the fast-inactivated state of neuronal Na(v) leading to greater depression of I(Na) during high-frequency stimulation, consistent with enhanced inhibition of fast firing neurones.