Gendered Diverging Destinies: Changing Family Structures and the Reproduction of Educational Inequalities Among Sons and Daughters in the United States

The prevalence of nontraditional family structures has increased over time, particularly among socioeconomically disadvantaged families. Because children's socioeconomic attainments are positively associated with growing up in a two-parent household, changing family structures are considered to have strengthened the reproduction of social inequalities across generations. However, several studies have shown that childhood family structure relates differently to educational outcomes for sons than for daughters. Therefore, we ask whether there are gender differences in the extent to which changing family structures have contributed to the college attainment gap between children from lower and higher socioeconomic backgrounds. We use data from the National Longitudinal Survey of Youth 1979 and 1997 cohorts to estimate extended Oaxaca–Blinder decomposition models that take into account cross-cohort changes in the prevalence of family structures and heterogeneity in the effects of childhood family structure on college attainment. We find that the argument that changes in family structures contributed to diverging destinies in college attainment holds for daughters but not for sons. This result is due to the different changes over time in the effects of childhood family structure by gender and socioeconomic background.

Ecological stoichiometry as a foundation for omics-enabled biogeochemical models of soil organic matter decomposition

Coupled biogeochemical cycles drive ecosystem ecology by influencing individual-to-community scale behaviors; yet the development of process-based models that accurately capture these dynamics remains elusive. Soil organic matter (SOM) decomposition in particular is influenced by resource stoichiometry that dictates microbial nutrient acquisition (‘ecological stoichiometry’). Despite its basis in biogeochemical modeling, ecological stoichiometry is only implicitly considered in high-resolution microbial investigations and the metabolic models they inform. State-of-science SOM decomposition models in both fields have advanced largely separately, but they agree on a need to move beyond seminal pool-based models. This presents an opportunity and a challenge to maximize the strengths of various models across different scales and environmental contexts. To address this challenge, we contend that ecological stoichiometry provides a framework for merging biogeochemical and microbiological models, as both explicitly consider substrate chemistries that are the basis of ecological stoichiometry as applied to SOM decomposition. We highlight two gaps that limit our understanding of SOM decomposition: (1) understanding how individual microorganisms alter metabolic strategies in response to substrate stoichiometry and (2) translating this knowledge to the scale of biogeochemical models. We suggest iterative information exchange to refine the objectives of high-resolution investigations and to specify limited dynamics for representation in large-scale models, resulting in a new class of omics-enabled biogeochemical models. Assimilating theoretical and modelling frameworks from different scientific domains is the next frontier in SOM decomposition modelling; advancing technologies in the context of stoichiometric theory provides a consistent framework for interpreting molecular data, and further distilling this information into tractable SOM decomposition models.

Proximate and distal factors associated with the stall in the decline of adolescent pregnancy in Uganda

Background Adolescent pregnancy in Uganda declined from 31% in 2000–01 to 25% in 2006 but thereafter stalled at 25% from 2006 to 2016. This paper investigates the factors associated with the recent stall in the rate of decline of adolescent pregnancy in Uganda. Methods We used logistic regression models for 4 years (2000–01, 2006, 2011 and 2016) of data from the Uganda Demographic Health Survey to explore proximate and distal factors of adolescent pregnancy in Uganda. We carried out Blinder-Oaxaca decomposition models to explore the contributions of different factors in explaining the observed decline in adolescent pregnancy between 2001 and 2006, and the subsequent stall between 2006 and 2016. Results We found that marriage among women aged 15–19 years, and early sexual debut, were strongly associated with adolescent pregnancy. These declined substantially between 2000 and 01 and 2006, leading to a decline in adolescent pregnancy. Their decline was in turn associated with rising levels of female education and household wealth. After 2006, education levels and household wealth gains stalled, with associated stalls in the decline of marriage among women aged 15–19 years and sexual debut, and a stall in the decline of adolescent pregnancy. Conclusions The stall in the decline of adolescent pregnancies in Uganda was linked to a stall in the reduction of adolescent marriage, which in turn was associated with limited progress in female educational attainment between 2006 and 2016. We emphasize the need for a renewed focus on girl’s education and poverty reduction to reduce adolescent pregnancy in Uganda and subsequently improve health outcomes for adolescent girls.

Demographic and socio-economic shifts partly explain the Martinican nutrition transition: an analysis of 10-year health and dietary changes (2003–2013) using decomposition models

Objective: The Caribbean has seen a dramatic shift in the obesity and chronic disease prevalence over the past decades, suggesting a nutrition transition. Simultaneously, Martinique has faced a demographic transition marked by significant population ageing. We aimed to differentiate the contribution of changes in health status and dietary intakes due to shifts in demographic and socio-economic characteristics (DSEC) from that due to unobserved factors. Design: Two cross-sectional surveys conducted in 2003 (n 743) and 2013 (n 573) on representative samples were used. Dietary intakes were estimated by 24-h recalls. The contribution of changes in health status and dietary intakes due to shifts in observed DSEC was differentiated from that due to unobserved factors over a 10-year interval, using Oaxaca–Blinder decomposition models. Setting: Martinique, French region in the Caribbean. Participants: Martinican adults (≥16 years). Results: Over the study period, health status deteriorated, partly owing to shifts in DSEC, explaining 62 % of the change in the prevalence of hypertension (+13 percentage points (pp)) and 48 % of waist circumference change (+3 cm). Diet quality decreased (mean adequacy ratio –2pp and mean excess ratio + 2 pp) and energy supplied by ultra-processed food increased (+4 pp). Shifts in DSEC marginally explained some changes in dietary intakes (e.g. increased diet quality), while the changes that remained unexplained were of opposite sign, with decreased diet quality, lower fruits, tubers and fish intakes and higher energy provided by ultra-processed foods. Conclusion: Explained dietary changes were of opposite sign to nutrition transition conceptual framework, probably because unobserved drivers are in play, such as food price trends or supermarkets spread.

Growth and Decomposition analysis of Rabi Pulse Crops in Rajasthan

The present study was conducted to analyze the growth rate and source of output growth in area, production and productivity of rabi pulse crops viz., gram and lentil crops in Rajasthan. The study was solely based on secondary time series data. The study period (1988-89 to 2017-18) has been divided into four periods namely period-I (1988-89 to 1997-98), period-II (1998-99 to 2007-08), period- III (2008-09 to 2017-18) and overall period (1988-89 to 2017-18). Exponential growth and principal decomposition models were used to measure the growth rates and relative contribution of factors in production of gram and lentil crops. The area, production and productivity of gram showed mixed pattern of growth at the rate of -0.46, 1.86 and 2.33 per cent, respectively during overall period. However, the area, production and productivity of lentil were reported positive growth with the magnitude of 11.94, 12.72 and 0.93 per cent, respectively in the state. The study revealed that the mixed growth rate was observed in area, production and productivity of gram while increasing growth was observed in area, production and productivity of lentil. During all the study periods, the expansion in area was effective to increase the production of lentil in Rajasthan. During period-I and II, the production of gram was mainly contributed by expansion in area while in the case of period-III and overall, the interaction effect was more dominant

Verification of a Leaf Litter Decomposition Model Based on Long-term Field Trials in Gongga Mountain, Qinghai-Tibetan Plateau, China

Background and aimsAlthough litter decomposition is a vital soil ecosystem process in forest ecosystems, most decomposition models are based on short-term decomposition experiments. Prediction of long-term decomposition dynamics using short-term decomposition models may lead to unreliable results. A leaf-litter decomposition model was evaluated and verified using a long-term field trial in Gongga Mountain, on the eastern flank of the Qinghai-Tibetan Plateau, China. Methods A 90-month experiment employing 360 broad-leaf litter (five species) samples were conducted using the litterbag method at three elevations (2250 m, 2780 m and 3000 m a.s.l.) in Gongga Mountain. The remaining litter mass was measured to fit a mathematical decomposition model by different exponential functions (two-, three-, four- and six-parameters) and akaike information criterion (AIC). ResultsThe four-parameter model (B) employed for each litter type among the four functions showed the highest R2 and lowest AIC value. The fast and slow decomposition rate constant (kf and ks) for a given litter at 2250 m was higher than that observed at 3000 m. ConclusionsThese results indicated that the four-parameter exponential function (two-pool model) was recommended as a suitable decomposition model of long-term broadleaf litter decomposition at different elevations on Gongga Mountain.