The Nicholas School of the Environment is one of ten graduate and professional schools at Duke University and is headquartered on Duke’s main campus in Durham, N.C. A secondary coastal facility, Duke University Marine Laboratory, is maintained in Beaufort, North Carolina. The Nicholas School is composed of three research divisions: Earth and Ocean Sciences, Environmental Sciences and Policy, and Marine Science and Conservation. The current dean of the Nicholas School is Toddi Steelman.
Gestational exposure to ambient air pollution has been linked to adverse birth outcomes. Folic acid (FA) supplementation supports fetal development, but the optimal timing for protective effects remains uncertain. This study aims to determine whether maternal FA supplementation prior to conception modifies the association between gestational air pollution exposure and birthweight-related outcomes in a population where most women also took FA during pregnancy. We analyzed data from 10,579 mother-child pairs from a preconception cohort in Shanghai, China. Ambient concentrations of PM2.5, PM10, NO2, and ozone were estimated at a residential level using spatiotemporal models for the preconception period and each trimester. We assessed whether preconception FA supplementation modified the association between air pollution exposure and birth outcomes, including birthweight, birthweight Z-score, small-for-gestational age (SGA), and low birthweight (LBW). Linear and logistic regression models with interaction terms, as well as stratified analyses by FA supplementation status, were applied. Children's sex-specific associations were also explored. Significant interactions between preconception FA supplementation and air pollution exposures were observed for birthweight and SGA. A 10 mu g/m(3) increase in PM2.5 exposure during pregnancy was associated with a -62.8 g (95% CI: -97.0, -28.6) change in birthweight and a 1.78 (95% CI: 1.16, 2.73) odds ratio for SGA among women without preconception FA supplementation. No such significant associations were found among women receiving preconception FA supplementation, with an estimated change of -1.7 g in birthweight (95% CI: -65.7 to 62.4) and an odds ratio of 0.70 for SGA (95% CI: 0.32-1.44). The protective effect appeared more pronounced for male infants than females. Maternal preconception FA supplementation can attenuate the adverse effects of gestational air pollution exposure on birthweight and SGA risk in women who also received FA supplementation during pregnancy. These findings support the importance of incorporating preconception FA supplementation as a protective measure against gestational exposure to air pollution.
The overall objective of this study was to better understand the neighborhood conditions, including neighborhood deprivation and tobacco and alcohol retail outlets, related to objectively measured secondhand exposure to tobacco smoke among children. This study employed a cross-sectional study design of biological samples, surveys, and geospatial data from children (median [inter-quartile range] 5 [4, 7] years) in the Newborn Epigenetics Study between 2006 and 2012. Variation in salivary cotinine levels in children was examined in relation to contemporaneous existence of retail outlets, including tobacco retail outlets (TRO), alcohol retail outlets (ARO), those that sell both tobacco and alcohol (TAROs), and neighborhood deprivation index (NDI) using American Community Survey data from 2014 to 2018, adjusting for individual-level variables including child race, gender, age, and maternal education and smoking. A Bayesian index modeling approach was used to estimate the relationship between child cotinine levels and outlet density and NDI using seven socioeconomic variables at the census tract level and to determine the most important variables related to secondhand smoke exposure. Significant and positive associations between counts of outlets and child cotinine in crude models (odds ratios 1.023, 1.033, 1.044 for a one-outlet increase, respectively) were observed. Associations with outlet density were attenuated when adjusting for important contextual- and individual-level variables including race and maternal education and smoking. Results support multi-level strategies to help reduce secondhand smoke exposure in children. To be effective, such efforts should aim to reduce maternal smoking, but also address tobacco and alcohol retail outlet density, especially in higher poverty neighborhoods.
In this study, we describe new results of excavations in the Dinaledi Subsystem of the Rising Star cave system, South Africa. In two areas within the Hill Antechamber and the Dinaledi Chamber, this work uncovered concentrations of abundant Homo naledi fossils including articulated, matrix-supported skeletal regions consistent with rapid covering by sediment prior to the decomposition of soft tissue. We additionally re-examine the spatial positioning of skeletal material and associated sediments within the Puzzle Box area, from which abundant H. naledi remains representing a minimum of six individuals were recovered in 2013 and 2014. Multiple lines of evidence exclude the hypothesis that skeletal remains from these three areas come from bodies that decomposed on the floor of the chamber or within a shallow depression prior to burial by sediments. The spatial positioning of skeletal material, the topography of the subsystem, and observations on sediments within and surrounding features exclude the hypothesis that rapid burial by sediment was a result of gravity-driven slumping or spontaneous movement of sediments. We present a minimal hypothesis of hominin cultural burial and test the evidence from all three areas, finding that this hypothesis is most compatible with the pattern of evidence. These results suggest that mortuary behavior, including cultural burial, was part of the repertoire of Homo naledi .
Recent excavations in the Rising Star Cave System of South Africa have revealed burials of the extinct hominin species Homo naledi. A combination of geological and anatomical evidence shows that hominins dug holes that disrupted the subsurface stratigraphy and interred the remains of H. naledi individuals, resulting in at least two discrete features within the Dinaledi Chamber and the Hill Antechamber. These are the most ancient interments yet recorded in the hominin record, earlier than evidence of Homo sapiens interments by at least 100,000 years. These interments along with other evidence suggest that diverse mortuary practices may have been conducted by H. naledi within the cave system. These discoveries show that mortuary practices were not limited to H. sapiens or other hominins with large brain sizes.
