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Seagrasses are important ecosystems that inhabit shallow coastal waters. They offer valuable ecosystem services (e.g., nutrient cycling, water quality control, and carbon sequestration) and provide favorable habitat for species (McGlathery et al., 2007; Nagelkerken et al., 2000; Oreska et al., 2017). They are also commonly referred to as natural eco-engineers that can effectively modify physical environments and stabilize the seabed (Jones et al., 1994). Previous studies on seagrass interactions with physical environments have shown that seagrasses can significantly modify the mean flow and turbulent structure (Fonseca & Fisher, 1986;

BackgroundThyroid nodules (TNs) are common thyroid lesions in older population. Few studies have focused on the prevalence of TNs and their relationship to lifestyle characteristics and dietary habits in centenarians. The current study aimed at determining the prevalence of TNs in Chinese centenarians by using high-resolution ultrasound (US) equipment and at investigating its relationship to lifestyle characteristics and dietary habits.Participants and methodsThe current study was part of the China Hainan Centenarian Cohort Study that was conducted in Hainan, an iodine-sufficient region in People’s Republic of China. A total of 874 permanent residents aged ≥100 years (mean age =102.8±2.8 years) without any missing data were included in the analysis.ResultsAmong the participants, 649 of them were detected at least one TN under the US examinations. The overall prevalence rate of TNs was 74.3%. The prevalence of TNs was higher in participants who were women, had hypertension, had diabetes, and were underweight compared with their counterparts. Multivariate logistic regression analyses showed that being female, hypertensive, and diabetic; betel quid consumption; and red meat consumption were independent risk factors, while being underweight and nut consumption were independent protective factors for TNs.ConclusionOur findings indicate that the presence of TNs was highly prevalent in Chinese centenarians, particularly in women. In addition to gender, having hypertension, having diabetes, and being underweight, the presence of TNs was independently associated with betel quid, red meat, and nut consumption. Further prospective studies are warranted to verify these associations in populations from different age strata, races, cultures, and iodine supplementation.

High electrical conductivity in the shallow mantle has long been recognized by electromagnetic depth soundings, but the origin remains debated. Various candidates, of which the two most popular are water enrichment in olivine (the dominant mineral in the upper mantle) and partial melt, have been proposed to explain the electrical anomalies. These models nearly exclusively assume a very low conductivity for dry or water‐poor olivine. Here, we show by experimental work that, under well‐controlled conditions of pressure, temperature, oxygen fugacity (fO2), and water inventory, the conductivity of olivine is in fact insensitive to water content at mantle temperature (e.g., >1,000°C), although the enhancement is substantial at relatively low temperature. In particular, the conductivity of olivine at temperature beyond ∼1,000°C is strikingly high, about 0.01–0.1 S/m, at the oxidizing conditions of the shallow mantle. The high conductivity is comparable to the geophysically measured high conductivity in many conductive regions of the shallow mantle. The results provide a new framework for understanding the electrical anomalies and electrical structure of the shallow mantle.

BackgroundHypovitaminosis D and depressive syndromes are common conditions in old adults. However, little is known about the relationship between vitamin D and depression in exceptional aged people. The objective of this study is to evaluate the relationship between vitamin D levels and depressive symptoms in Chinese longevous persons.MethodsWe used a dataset from a cross-sectional survey of a sample of Chinese longevous people with self-reported age 100 or older, including 175 men and 765 women, was conducted from June 2014 to December 2016 in Hainan Province, China. Data on demographics, lifestyle characteristics and health conditions were collected using a structured questionnaire. Anthropometrics and blood samples were obtained following the standard procedure. Depressive symptoms of the participants were assessed using a shortened version of the Geriatric Depression Scale (GDS-15). Serum vitamin D levels were measured using an automated radioimmunoassay.ResultsThe prevalence of longevous persons with depressive symptoms among the sample was 32.2% (95% confidence interval: 29.7–34.7%). Serum vitamin D levels were lower in participants with depressive symptoms than in those without (20.8 ± 8.7 vs. 23.7 ± 9.7, ng/mL). Vitamin D deficiency was an independent risk factor for depression after controlling for the potential covariates (Odds ratio = 1.47, 95% Confidence interval = 1.08–2.00; p = 0.014). A negative relationship between serum vitamin D levels and depressive symptoms was also detected, and the relationship remained significant after adjusting for a wide range of other covariates. The multivariate adjusted odds ratio of depressive symptoms for the lowest versus highest quartiles of vitamin D levels was 1.73 (95% confidence interval: 1.10–2.72), and the adjusted odds ratio with a 5 ng/mL decrement of serum 25OHD levels was 1.10 (95% confidence interval: 1.01–1.19).ConclusionsThis study showed an inverse association between vitamin D levels and depressive symptoms among Chinese longevous persons. Depressive symptoms should be screened in longevous persons who had vitamin D deficiency. Further studies on vitamin D supplement and prevention along with treatment of depression are needed among very old population.

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