Variations in carbon burial and sediment accretion along a tidal creek in a Florida salt marsh

Salt marshes store large quantities of carbon in the form of buried organic matter (OM) and consequently play a major role in the global carbon cycle, yet vertical accretion and carbon burial rates (CBRs) can vary by orders of magnitude on small spatial scales. The goal of this study was to provide insight into carbon burial variability of a single tidal salt marsh. Six marsh sediment cores were collected along a tidal creek in the Big Bend of Florida from the mouth to the coastal forest within the marsh levee and plain. Each was analyzed for porosity, % OM, total organic carbon (TOC), total nitrogen (TN), δ13C, δ15N, and excess 210Pb to determine vertical accretion and CBRs. Porosity, % OM, and TOC and TN were found to be highest in the low marsh and within the marsh levee. Stable isotopes of OM indicate the source is dominated by C3 plant species in both the levee and plain. Average vertical accretion ranges from 0.9 mm yr−1 to 2.2 mm yr−1 with the slowest rates in the low marsh. Average carbon burial ranges from 49.5 g OC m−2 yr−1 to 109.5 g OC m−2 yr−1. High carbon burial associated with low sediment accumulation in the Low Marsh and low carbon burial associated with high sediment accumulation rates in the High Marsh are typical in this marsh. These variations imply that the highest carbon burial occurs in the zone most vulnerable to loss via inundation and erosion

Histomorphometric study of growth plate subjected to different mechanical conditions (compression, tension and neutralization): an experimental study in lambs. Mechanical growth plate behavior

We studied the morphologic effect of low mechanical stresses (compression, tension and neutralization) on the growth cartilage with an external fixator in 18 young lambs. On radiography, we only found more length in the femora subjected to tension (P < 0.05). Bony bridges were not present, nor were there signs of altered vascularization or Ranvier's perichondral ring. Histomorphometrically, in the group subjected to tension, the germinative layer in the femur was higher (P < 0.001) in the bones that had undergone surgery. The proliferative layer was lower in the operated tibia (P < 0.001), and the hypertrophic layer was higher in operated tibias and femora (P < 0.001). In the group subjected to compression, the germinative layer in the femora was higher in the operated bones (P < 0.05); the proliferative layer of the tibia was lower (P < 0.001) and the hypertrophic layer was higher (P < 0.001) in both operated bones. In the neutralization group, the proliferative layer of both operated bones presented lower values (P < 0.001) and the hypertrophic layer was higher (P < 0.001) than that in the control group

Effects of Sediment Delivery Changes on Carbon Burial Within the Modern and Abandoned Delta Lobes of the Yellow River, China

Globally, deltaic wetlands sequester large volumes of terrestrial and marine-derived organic carbon. Diminishing sediment supply via river diversions, dams, and/or sea level rise threatens this stored carbon by enhancing erosion, thereby potentially releasing CO2 back to the atmosphere during remineralization of organic matter. The Yellow River delta, located in the Bohai Sea, China, has undergone intense anthropogenic manipulation since the 1950s including rerouting of the river mouth to expand the delta for oil exploitation. The goal of this study is to identify the impacts of river course diversions on sources and rates of carbon burial in the modern and abandoned delta lobes of the Yellow River delta. In 2016, we collected four cores total in abandoned and modern deltaic lobes and measured vertical accretion, total carbon, total nitrogen, δ13C, and n-alkanes. The highest average mass accretion rate of 12,470.1 g m−2 year−1 is observed in the abandoned delta, although it no longer receives direct river sediment input. The modern and abandoned deltas are currently outpacing sea level rise, but vertical accretion rates are influenced by sediment trapping practices in the modern delta and redistribution of eroded sediments in the abandoned. Average carbon burial rates across both delta sites vary between 7.2 and 14.9 g OC m−2 year−1. Sediment-associated carbon at both sites is dominantly sourced from the Loess Plateau. To conserve wetlands across the Yellow River delta, sediment management practices that periodically reintroduce sediment-laden river water to former river courses, such as in the Mississippi delta, are suggested

Trajectories of alcohol consumption during life and the risk of developing breast cancer

Background: Whether there are lifetime points of greater sensitivity to the deleterious effects of alcohol intake on the breasts remains inconclusive. Objective: To compare the influence of distinctive trajectories of alcohol consumption throughout a woman’s life on development of breast cancer (BC). Methods: 1278 confirmed invasive BC cases and matched (by age and residence) controls from the Epi-GEICAM study (Spain) were used. The novel group-based trajectory modelling was used to identify different alcohol consumption trajectories throughout women’s lifetime. Results: Four alcohol trajectories were identified. The first comprised women (45%) with low alcohol consumption (<5 g/day) throughout their life. The second included those (33%) who gradually moved from a low alcohol consumption in adolescence to a moderate in adulthood (5 to <15 g/day), never having a high consumption; and oppositely, women in the third trajectory (16%) moved from moderate consumption in adolescence, to a lower consumption in adulthood. Women in the fourth (6%) moved from a moderate alcohol consumption in adolescence to the highest consumption in adulthood (=15 g/day), never having a low alcohol consumption. Comparing with the first trajectory, the fourth doubled BC risk (OR 2.19; 95% CI 1.27, 3.77), followed by the third (OR 1.44; 0.96, 2.16) and ultimately by the second trajectory (OR 1.17; 0.86, 1.58). The magnitude of BC risk was greater in postmenopausal women, especially in those with underweight or normal weight. When alcohol consumption was independently examined at each life stage, =15 g/day of alcohol consumption in adolescence was strongly associated with BC risk followed by consumption in adulthood. Conclusions: The greater the alcohol consumption accumulated throughout life, the greater the risk of BC, especially in postmenopausal women. Alcohol consumption during adolescence may particularly influence BC risk. © 2021, The Author(s)

Risk of type 2 diabetes according to traditional and emerging anthropometric indices in Spain, a mediterranean country with high prevalence of obesity: results from a large-scale prospective cohort study

Background: Obesity is a major risk factor for type 2 diabetes mellitus (T2DM). A proper anthropometric characterisation of T2DM risk is essential for disease prevention and clinical risk assessement. Methods: Longitudinal study in 37 733 participants (63% women) of the Spanish EPIC (European Prospective Investigation into Cancer and Nutrition) cohort without prevalent diabetes. Detailed questionnaire information was collected at baseline and anthropometric data gathered following standard procedures. A total of 2513 verified incident T2DM cases occurred after 12.1 years of mean follow-up. Multivariable Cox regression was used to calculate hazard ratios of T2DM by levels of anthropometric variables. Results: Overall and central obesity were independently associated with T2DM risk. BMI showed the strongest association with T2DM in men whereas waist-related indices were stronger independent predictors in women. Waist-to-height ratio revealed the largest area under the ROC curve in men and women, with optimal cut-offs at 0.60 and 0.58, respectively. The most discriminative waist circumference (WC) cut-off values were 99.4 cm in men and 90.4 cm in women. Absolute risk of T2DM was higher in men than women for any combination of age, BMI and WC categories, and remained low in normal-waist women. The population risk of T2DM attributable to obesity was 17% in men and 31% in women. Conclusions: Diabetes risk was associated with higher overall and central obesity indices even at normal BMI and WC values. The measurement of waist circumference in the clinical setting is strongly recommended for the evaluation of future T2DM risk in women

Virtual Ontogeny of Cortical Growth Preceding Mental Illness

Background: Morphology of the human cerebral cortex differs across psychiatric disorders, with neurobiology and developmental origins mostly undetermined. Deviations in the tangential growth of the cerebral cortex during pre/perinatal periods may be reflected in individual variations in cortical surface area later in life. Methods: Interregional profiles of group differences in surface area between cases and controls were generated using T1-weighted magnetic resonance imaging from 27,359 individuals including those with attention-deficit/hyperactivity disorder, autism spectrum disorder, bipolar disorder, major depressive disorder, schizophrenia, and high general psychopathology (through the Child Behavior Checklist). Similarity of interregional profiles of group differences in surface area and prenatal cell-specific gene expression was assessed. Results: Across the 11 cortical regions, group differences in cortical area for attention-deficit/hyperactivity disorder, schizophrenia, and Child Behavior Checklist were dominant in multimodal association cortices. The same interregional profiles were also associated with interregional profiles of (prenatal) gene expression specific to proliferative cells, namely radial glia and intermediate progenitor cells (greater expression, larger difference), as well as differentiated cells, namely excitatory neurons and endothelial and mural cells (greater expression, smaller difference). Finally, these cell types were implicated in known pre/perinatal risk factors for psychosis. Genes coexpressed with radial glia were enriched with genes implicated in congenital abnormalities, birth weight, hypoxia, and starvation. Genes coexpressed with endothelial and mural genes were enriched with genes associated with maternal hypertension and preterm birth. Conclusions: Our findings support a neurodevelopmental model of vulnerability to mental illness whereby prenatal risk factors acting through cell-specific processes lead to deviations from typical brain development during pregnancy

X chromosome inactivation does not necessarily determine the severity of the phenotype in Rett syndrome patients

Rett syndrome (RTT) is a severe neurological disorder usually caused by mutations in the MECP2 gene. Since the MECP2 gene is located on the X chromosome, X chromosome inactivation (XCI) could play a role in the wide range of phenotypic variation of RTT patients; however, classical methylation-based protocols to evaluate XCI could not determine whether the preferentially inactivated X chromosome carried the mutant or the wild-type allele. Therefore, we developed an allele-specific methylation-based assay to evaluate methylation at the loci of several recurrent MECP2 mutations. We analyzed the XCI patterns in the blood of 174 RTT patients, but we did not find a clear correlation between XCI and the clinical presentation. We also compared XCI in blood and brain cortex samples of two patients and found differences between XCI patterns in these tissues. However, RTT mainly being a neurological disease complicates the establishment of a correlation between the XCI in blood and the clinical presentation of the patients. Furthermore, we analyzed MECP2 transcript levels and found differences from the expected levels according to XCI. Many factors other than XCI could affect the RTT phenotype, which in combination could influence the clinical presentation of RTT patients to a greater extent than slight variations in the XCI pattern