An integrated and open-ended experiment

In this article we discuss an exciting experiment in non-linear dynamics. This provides an imaginative platform for bringing in chemical, physical, biological, mathematical and computational sciences together. There are implications for earth sciences as well. B M Deb is a theoretical chemist who has been designing experiments for chemistry teaching laboratories for more than thirty years. Mainak Sadhukhan, Sudarson Sekhar Sinha and Sucheta Sengupta were students of PBIR-Chemical Sciences. Ranjit Biswas is a physical chemist working on both theory and experiment in chemical dynamics.     

School-enrollment rates and trends,gender, and fertility: a cross-national analysis

The analysis of the association between educational status and fertility decline is performed 1) by examining the rates of enrollment in primary and secondary schools by gender and 2) by assessing the effects of the change/spread in rates of enrollment between 1965 and 1986. 59 countries were involved in the cross-sectional analysis. Variables included the logged crude birth rate, total enrollment rates, enrollment rates by gender, male-female ratios, the growth rate for each educational measure by world system status (core, peripheral, and semiperipheral countries), control variables (economic growth, family planning, multinational corporate penetration, women's labor force participation, child mortality rate, social insurance programs), and enrollment changes. The evidence reflects a strong association between levels of enrollment of girls in primary and secondary school and gender inequality and fertility declines. Caldwell's theory of the flows of wealth and the spread of education effect was found to have little support. High levels of female enrollment and low levels of gender inequality in access to schooling are associated with fertility declines. Caldwell's theory is that this indicates a decline in patriarchy, change in women's familial roles and a shift to a more egalitarian family structure. Increases in female education mean higher status and more power for women.     

Modelling impact of dredging and dumping in ebb-flood channel systems

For a channel-shoal system in a funnel-shaped basin the impact of dredging and dumping is investigated using a complex process-based model. First, the residual flow and sediment transport circulations are analysed for the channel-shoal pattern, which has emerged after a long-term model simulation. Results are compared to the Western Scheldt estuary, which forms the inspiration for this study. Subsequently, different dredge and dump scenarios are modelled, according to a conceptual model, in which ebb-and flood-channels and enclosed shoals form morphodynamic units (cells) with their own sediment circulation. Model results show that dumping sediment in a channel further reduces the channel depth and induces erosion in the opposite channel, which enhances tilting of the cross-section of the cell and eventually can lead to the degeneration of a multiple channel system into a single channel. The impact of different dredging and dumping cases agrees with results from a stability analysis. This means that this type of model applied to a realistic geometry can potentially be used for better prediction of the impact of human interventions.     

Compressive Strength of Hydrostatic-Stress-Sensitive Materials at High Strain-Rates

Many engineering materials demonstrate dynamic enhancement of their compressive strength with the increase of strain-rate, which have been included in material models to improve the reliability of numerical simulations of the material and structural responses under impact and blast loads. The strain-rate effects on the dynamic compressive strength of a range of engineering materials which behave in hydrostatic-stress-sensitive manner were investigated. It is concluded that the dynamic enhancement of the compressive strength of a hydrostatic-stress-sensitive material may include inertia-induced lateral confinement effects, which, as a non-strain-rate factor, may greatly enhance the compressive strength of these materials. Some empirical formulae based on the dynamic stress-strain measurements over-predict the strain-rate effects on the compressive strength of these hydrostatic-stress-sensitive materials, and thus may over-estimate the structural resistance to impact and blast loads, leading to non-conservative design of protective structures.     

“我不能”的葬礼

常言道:失败乃成功之母。这也是我们在失败时经常用来鼓励自己继续前行的话。如果说这句话略带点阿Q,是精神胜利法的话,那么下面这则小故事则给人置之死地而后生的破釜沉舟的勇气和力量。细细品味吧!     

Inhibitory Control Across the Preschool Years: Developmental Changes and Associations with Parenting

The normative developmental course of inhibitory control between 2.5 and 6.5 years, and associations with maternal and paternal sensitivity and intrusiveness were tested. The sample consisted of 383 children (52.5% boys). During four annual waves, mothers and fathers reported on their children’s inhibitory control using the Children's Behavior Questionnaire. During the first wave, mothers’ and fathers’ sensitivity and intrusiveness were observed and coded with the Emotional Availability Scales. Inhibitory control exhibited partial scalar invariance over time, and increased in a decelerating rate. For both mothers and fathers, higher levels of sensitivity were associated with a higher initial level of children's inhibitory control, whereas higher levels of intrusiveness predicted a slower increase in children's inhibitory control.     

A Little Autonomy Support Goes a Long Way: Daily Autonomy-Supportive Parenting,Child Well-Being,Parental Need Fulfillment,and Change in Child,Family, and Parent Adjustment Across the Adaptation to the COVID-19 Pandemic

This study examined the effects of daily parental autonomy support on changes in child behavior, family environment, and parental well-being across 3 weeks during the COVID-19 pandemic in Germany. Day-to-day associations among autonomy-supportive parenting, parental need fulfillment, and child well-being were also assessed. Parents (longitudinal N = 469; M_age = 42.93, SD_age = 6.40) of school children (6–19 years) reported on adjustment measures at two measurement occasions and completed up to 21 daily online questionnaires in the weeks between these assessments. Results from dynamic structural equation models suggested reciprocal positive relations among autonomy-supportive parenting and parental need fulfillment. Daily parental autonomy support, parental need fulfillment, and child well-being partially predicted change in adjustment measures highlighting the central role of daily parenting for children’s adjustment during the pandemic.     

Prenatal Neighborhood Ethnocultural Context and the Mental Health of Mothers and Children in Low-Income Mexican American Families

Socioeconomically disadvantaged neighborhoods increase the risk for poor mental health among residents, yet protective factors may operate alongside risk. This study evaluated the influence of the prenatal neighborhood ethnocultural context on child behavior problems and maternal depressive symptoms. Prenatal maternal role expectations, prenatal culture-specific stress, and postpartum depression (PPD) symptoms were evaluated as mediators. Participants included 322 low-income, Mexican American mother-child dyads. Women (M_age = 27.8) reported on proposed mediators, maternal depressive symptoms, and child behavior problems at 4.5 years. Neighborhood Latinx concentration was obtained from census data. Higher Latinx concentration predicted fewer maternal depressive symptoms and child behavior problems, mediated through role expectations and PPD symptoms. Results suggest prenatal neighborhood context to impact later maternal and child mental health.     

Incorporating Uncertainty Into Parallel Analysis for Choosing the Number of Factors via Bayesian Methods

A number of psychometricians have suggested that parallel analysis (PA) tends to yield more accurate results in determining the number of factors in comparison with other statistical methods. Nevertheless, all too often PA can suggest an incorrect number of factors, particularly in statistically unfavorable conditions (e.g., small sample sizes and low factor loadings). Because of this, researchers have recommended using multiple methods to make judgments about the number of factors to extract. Implicit in this recommendation is that, when the number of factors is chosen based on PA, uncertainty nevertheless exists. We propose a Bayesian parallel analysis (B-PA) method to incorporate the uncertainty with decisions about the number of factors. B-PA yields a probability distribution for the various possible numbers of factors. We implement and compare B-PA with a frequentist approach, revised parallel analysis (R-PA), in the contexts of real and simulated data. Results show that B-PA provides relevant information regarding the uncertainty in determining the number of factors, particularly under conditions with small sample sizes, low factor loadings, and less distinguishable factors. Even if the indicated number of factors with the highest probability is incorrect, B-PA can show a sizable probability of retaining the correct number of factors. Interestingly, when the mode of the distribution of the probabilities associated with different numbers of factors was treated as the number of factors to retain, B-PA was somewhat more accurate than R-PA in a majority of the conditions.