Wearable Biomonitoring Platform for the Assessment of Stress and its Impact on Cognitive Performance of Firefighters: An Experimental Study

Background: Stress is a complex process with an impact on health and performance. The use of wearable sensor-based monitoring systems offers interesting opportunities for advanced health care solutions for stress analysis. Considering the stressful nature of firefighting and its importance for the community’s safety, this study was conducted for firefighters. Objectives: A biomonitoring platform was designed, integrating different biomedical systems to enable the acquisition of real time Electrocardiogram (ECG), computation of linear Heart Rate Variability (HRV) features and collection of perceived stress levels. This platform was tested using an experimental protocol, designed to understand the effect of stress on firefighter’s cognitive performance, and whether this effect is related to the autonomic response to stress. Method: The Trier Social Stress Test (TSST) was used as a testing platform along with a 2-Choice Reaction Time Task. Linear HRV features from the participants were acquired using an wearable ECG. Self-reports were used to assess perceived stress levels. Results: The TSST produced significant changes in some HRV parameters (AVNN, SDNN and LF/HF) and subjective measures of stress, which recovered after the stress task. Although these short-term changes in HRV showed a tendency to normalize, an impairment on cognitive performance was found after performing the stress event. Conclusion: Current findings suggested that stress compromised cognitive performance and caused a measurable change in autonomic balance. Our wearable biomonitoring platform proved to be a useful tool for stress assessment and quantification. Future studies will implement this biomonitoring platform for the analysis of stress in ecological settings

African-specific improvement of a polygenic hazard score for age at diagnosis of prostate cancer

Polygenic hazard score (PHS) models are associated with age at diagnosis of prostate cancer. Our model developed in Europeans (PHS46) showed reduced performance in men with African genetic ancestry. We used a cross-validated search to identify single nucleotide polymorphisms (SNPs) that might improve performance in this population. Anonymized genotypic data were obtained from the PRACTICAL consortium for 6253 men with African genetic ancestry. Ten iterations of a 10-fold cross-validation search were conducted to select SNPs that would be included in the final PHS46+African model. The coefficients of PHS46+African were estimated in a Cox proportional hazards framework using age at diagnosis as the dependent variable and PHS46, and selected SNPs as predictors. The performance of PHS46 and PHS46+African was compared using the same cross-validated approach. Three SNPs (rs76229939, rs74421890 and rs5013678) were selected for inclusion in PHS46+African. All three SNPs are located on chromosome 8q24. PHS46+African showed substantial improvements in all performance metrics measured, including a 75% increase in the relative hazard of those in the upper 20% compared to the bottom 20% (2.47-4.34) and a 20% reduction in the relative hazard of those in the bottom 20% compared to the middle 40% (0.65-0.53). In conclusion, we identified three SNPs that substantially improved the association of PHS46 with age at diagnosis of prostate cancer in men with African genetic ancestry to levels comparable to Europeans

The Influence of Age and Sex on Genetic Associations with Adult Body Size and Shape : A Large-Scale Genome-Wide Interaction Study

Genome-wide association studies (GWAS) have identified more than 100 genetic variants contributing to BMI, a measure of body size, or waist-to-hip ratio (adjusted for BMI, WHRadjBMI), a measure of body shape. Body size and shape change as people grow older and these changes differ substantially between men and women. To systematically screen for age-and/or sex-specific effects of genetic variants on BMI and WHRadjBMI, we performed meta-analyses of 114 studies (up to 320,485 individuals of European descent) with genome-wide chip and/or Metabochip data by the Genetic Investigation of Anthropometric Traits (GIANT) Consortium. Each study tested the association of up to similar to 2.8M SNPs with BMI and WHRadjBMI in four strata (men 50y, women 50y) and summary statistics were combined in stratum-specific meta-analyses. We then screened for variants that showed age-specific effects (G x AGE), sex-specific effects (G x SEX) or age-specific effects that differed between men and women (G x AGE x SEX). For BMI, we identified 15 loci (11 previously established for main effects, four novel) that showed significant (FDR= 50y). No sex-dependent effects were identified for BMI. For WHRadjBMI, we identified 44 loci (27 previously established for main effects, 17 novel) with sex-specific effects, of which 28 showed larger effects in women than in men, five showed larger effects in men than in women, and 11 showed opposite effects between sexes. No age-dependent effects were identified for WHRadjBMI. This is the first genome-wide interaction meta-analysis to report convincing evidence of age-dependent genetic effects on BMI. In addition, we confirm the sex-specificity of genetic effects on WHRadjBMI. These results may providefurther insights into the biology that underlies weight change with age or the sexually dimorphism of body shape.Peer reviewe

A Numerical Examination of an Unsteady Nonlinear MHD Flow in the Presence of Thermal Radiation and Heat Generation

In this study, the spectral perturbation method and the spectral relaxation method are used to solve the nonlinear differential equations of an unsteady nonlinear MHD flow in the presence of thermal radiation and heat generation. The SPM is mainly based on series expansion, generating series approximation coupled with the Chebyshev spectral method. The numerical results generated using the spectral perturbation method were compared with those found in the literature, and the two results were in good agreement

Desempenho de populações de alfafa sob desfolhação Performance of alfalfa populations under defoliation

Neste trabalho, objetivou-se verificar a resposta de populações de alfafa à desfolhação. Avaliaram-se duas populações de alfafa Crioula (tipo-feno), selecionada em estádio de plântula de acordo com o comprimento do segundo entrenó (EC = 1,5 cm; EL = 2,5 cm) e uma do cultivar Alfagraze (tipo-pastejo). As plantas foram cultivadas em vasos nos meses de março a agosto de 2005 e submetidas a uma combinação de altura (2 e 8 cm) e freqüência de corte (semanal, quinzenal e mensal) durante 141 dias. Não houve diferença quanto à produção da matéria seca (MS) aérea sob cortes semanais e quinzenais. Com cortes mensais, a população Crioula-EL, com maior altura e quantidade de hastes, superou as demais. Os cultivares Alfagraze e Crioula-EC foram similares quanto à quantidade de MS subterrânea. As populações de alfafa diferiram na resposta ao manejo de corte e apresentaram declínio gradual na MS quando submetidas a cortes mais freqüentes, com maior sobrevivência do cultivar Alfagraze em comparação aos cultivares Crioula-EC e Crioula-EL. O cultivar Alfagraze diferiu das populações do cultivar Crioula e apresentou menor altura, maior diâmetro, maior proporção de hastes da coroa e maior alocação de MS na parte subterrânea, portanto, estas características estão relacionadas ao tipo-pastejo. O comprimento do entrenó da plântula poderia ser utilizado complementarmente para selecionar populações de alfafa com maior aptidão ao pastejo, o que torna possível obter populações com variabilidade de produção de matéria seca e sobrevivência.<br>This work aimed to evaluate the performance of alfalfa populations in response to defoliation. Two populations of alfalfa cv. Crioula (hay-type) and one population of alfalfa cv. Alfagraze (grazing-type) were evaluated, being selected at seedling stage according to the length of the second internode (EC=1.5 cm; EL=2.5 cm). The trial was performed in pots, between February and August/2005. The populations were harvest at two cutting intensities (2 and 8 cm) and three cutting frequencies (weekly, fortnightly and monthly) during 141 days. There was no difference on shoot dry matter (DM) yield between weekly and fortnightly cuttings; the Crioula-EL, under monthly cuttings was the tallest and had higher amount of stems, surpassing the others. There was similarity between the cultivar Alfagraze and Crioula-SI regarding underground DM biomass. Alfalfa populations responded differently to defoliation management, with a gradual decline on DM yield under more frequent cuttings and a higher survival of plants from Alfagraze compared to Crioula-EC and Crioula-EC. Alfagraze cultivar differed from the Crioula populations, presenting shorter plants, higher proportion of stems originate from the crown and a higher allocation of DM to the underground parts, indicating that these characteristics belong to a grazing-type alfalfa. The length of seedling internodes could be used as a complementary morphological marker to select alfalfa populations more adapted to grazing. In this way, it is possible to obtain populations with DM yield variability and survival