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Hypertension prevalence is on the rise in low- and middle-income countries (LMICs) like South Africa, and migration and its concomitant urbanization are often considered to be associated with this rise. However, relatively little is known about the relationship between blood pressure (BP) and internal migration – a highly prevalent population process in LMICs. This study employed data for a group of 194 adult men and women from an original pilot dataset drawn from the Agincourt Health and Demographic Surveillance System in north-east South Africa conducted in 2012. Migrants in the sample were identified, tracked and interviewed. The relationship between BP and migration distance and the number of months an individual spent away from his/her home village was estimated using robust OLS regression, controlling for a series of socioeconomic, health and behavioural characteristics. It was found that migrants who moved a longer distance and for longer durations had significantly higher systolic and diastolic blood pressures compared with shorter-term migrants and those who remained nearby or in their home village. These associations remained robust and statistically significant when adjusting for measures of socioeconomic conditions, as well as body mass index and the number of meals consumed per day. Migration, both in terms of distance and time away, explained significant variation in the blood pressure of migrants in this typical South African context. The findings suggest the need for further studies of the nutritional and psycho-social factors associated with geographic mobility that may be important to understand rising hypertension levels in LMICs.
A lasting legacy of the International Polar Year (IPY) 2007–2008 was the promotion of the Permafrost Young Researchers Network (PYRN), initially an IPY outreach and education activity by the International Permafrost Association (IPA). With the momentum of IPY, PYRN developed into a thriving network that still connects young permafrost scientists, engineers, and researchers from other disciplines. This research note summarises (1) PYRN’s development since 2005 and the IPY’s role, (2) the first 2015 PYRN census and survey results, and (3) PYRN’s future plans to improve international and interdisciplinary exchange between young researchers. The review concludes that PYRN is an established network within the polar research community that has continually developed since 2005. PYRN’s successful activities were largely fostered by IPY. With >200 of the 1200 registered members active and engaged, PYRN is capitalising on the availability of social media tools and rising to meet environmental challenges while maintaining its role as a successful network honouring the legacy of IPY.
Elevated levels of pro-inflammatory cytokines are consistently reported in schizophrenia (SZ) and bipolar-I disorder (BD), as well as among individuals who have been exposed to childhood trauma. However, higher levels of inflammatory markers in these disorders are yet to be investigated with respect to levels of exposure to different types of childhood trauma.
Participants were 68 cases with a diagnosis of schizophrenia/schizoaffective disorder (SZ), 69 cases with a diagnosis of psychotic BD and 72 healthy controls (HC). Serum levels of interleukin 6 (IL-6), tumour necrosis factor-α (TNF-α) and C-reactive protein (CRP) were quantified, and childhood trauma exposure was assessed with the Childhood Trauma Questionnaire.
The SZ group had significantly higher levels of IL-6, TNF-α and CRP when compared with the HC group (all p < 0.05, d = 0.41–0.63), as well as higher levels of TNF-α when compared with the BD group (p = 0.014, d = 0.50); there were no differences between the BD and HC groups for any markers. Exposure to sexual abuse was positively associated (standardised β = 0.326, t = 2.459, p = 0.018) with levels of CRP in the SZ group, but there were no significant associations between any form of trauma exposure and cytokine levels in the HC or BD groups.
These results contribute to the evidence for a chronic state of inflammation in SZ but not BD cases. Differential associations between trauma exposure and levels of pro-inflammatory cytokines across the diagnostic categories suggest that trauma may impact biological (stress and immune) systems differently in these patient groups.
Various practical issues affecting atom probe tomography (APT) analysis of III-nitride semiconductors have been studied as part of an investigation using a c-plane InAlN/GaN heterostructure. Specimen preparation was undertaken using a focused ion beam microscope with a mono-isotopic Ga source. This enabled the unambiguous observation of implantation damage induced by sample preparation. In the reconstructed InAlN layer Ga implantation was demonstrated for the standard “clean-up” voltage (5 kV), but this was significantly reduced by using a lower voltage (e.g., 1 kV). The characteristics of APT data from the desorption maps to the mass spectra and measured chemical compositions were examined within the GaN buffer layer underlying the InAlN layer in both pulsed laser and pulsed voltage modes. The measured Ga content increased monotonically with increasing laser pulse energy and voltage pulse fraction within the examined ranges. The best results were obtained at very low laser energy, with the Ga content close to the expected stoichiometric value for GaN and the associated desorption map showing a clear crystallographic pole structure.
We surveyed hospital epidemiologists and infection preventionists on their usage of and satisfaction with infection prevention–specific software supplementing their institution’s electronic medical record. Respondents with supplemental software were more satisfied with their software’s infection prevention and antimicrobial stewardship capabilities than those without. Infection preventionists were more satisfied than hospital epidemiologists.
Obesity has been shown to be associated with depression and it has been suggested that higher body mass index (BMI) increases the risk of depression and other common mental disorders. However, the causal relationship remains unclear and Mendelian randomisation, a form of instrumental variable analysis, has recently been employed to attempt to resolve this issue.
To investigate whether higher BMI increases the risk of major depression.
Two instrumental variable analyses were conducted to test the causal relationship between obesity and major depression in RADIANT, a large case–control study of major depression. We used a single nucleotide polymorphism (SNP) in FTO and a genetic risk score (GRS) based on 32 SNPs with well-established associations with BMI.
Linear regression analysis, as expected, showed that individuals carrying more risk alleles of FTO or having higher score of GRS had a higher BMI. Probit regression suggested that higher BMI is associated with increased risk of major depression. However, our two instrumental variable analyses did not support a causal relationship between higher BMI and major depression (FTO genotype: coefficient −0.03, 95% CI −0.18 to 0.13, P = 0.73; GRS: coefficient −0.02, 95% CI −0.11 to 0.07, P = 0.62).
Our instrumental variable analyses did not support a causal relationship between higher BMI and major depression. The positive associations of higher BMI with major depression in probit regression analyses might be explained by reverse causality and/or residual confounding.
Deer exclosure is an important management strategy for encouraging woodland regeneration in the presence of high numbers of Cervus elaphus L. This could pose a threat to important saxicolous lichen communities as a result of competition from bryophytes and other vegetation. This investigation compared the bryophyte and lichen communities associated with siliceous rock outcrops and boulders inside and outside a number of exclosures in wet heath vegetation at the Gruinard, Letterewe and Little Gruinard estates in Wester Ross. Species cover data were recorded from 6600·2×0·2 m quadrats, allocated to three different aspects of rocks, from 22 pairs of plots (placed either side of a deer fence) with randomization at each level of this hierarchy. The data were analyzed using linear mixed effects models. Mean lichen cover, diversity and species richness were significantly lower in quadrats on rocks within the exclosures. Mean bryophyte cover was significantly higher in quadrats on rocks inside the deer fence and was shown to have a highly significant negative relationship with total lichen cover. Saxicolous lichen species are particularly affected by the increase in shading and litter accumulation from the surrounding plants and the subsequent growth of bryophytes and heath vegetation on rocks within the exclosures. The results of this study have implications for the use of exclosures at locations where there are important saxicolous lichen communities.