Long-term trends in BMI: are contemporary childhood BMI growth references appropriate when looking at historical datasets?

Background Body mass index (BMI) is the most widely used surrogate measure of adiposity, and BMI z-scores are often calculated when comparing childhood BMI between populations and population sub-groups. Several growth references are currently used as the basis for calculation of such z-scores, for both contemporary cohorts as well as cohorts born decades ago. Due to the widely acknowledged increases in childhood obesity over recent years it is generally assumed that older birth cohorts would have lower BMIs relative to the current standards. However, this reasonable assumption has not been formally tested.   Methods Two growth references (1990 UK and 2000 CDC) are used to calculate BMI z-scores in three historical British national birth cohorts (National Survey of Health and Development (1958), National Child Development Study (1958) and British Cohort Study (1970)). BMI z-scores are obtained for each child at each follow-up age using the lambda-mu-sigma (LMS) method, and their distributions examined.   Results Across all three cohorts, median BMI z-score at each follow-up age is observed to be positive in early childhood. This is contrary to what might have been expected given the assumed temporal increase in childhood BMI. However, z-scores then decrease and become negative during adolescence, before increasing once more.   Conclusions The differences in BMI distribution between the historical cohorts and the contemporary growth references appear systematic and similar across the cohorts. This might be explained by contemporary reference data describing a faster tempo of weight increase relative to height than observed in older birth cohorts. Comparisons using z-scores over extended periods of time should therefore be interpreted with caution

Factors associated with excess all-cause mortality in the first wave of the COVID-19 pandemic in the UK: A time series analysis using the Clinical Practice Research Datalink

BACKGROUND: Excess mortality captures the total effect of the Coronavirus Disease 2019 (COVID-19) pandemic on mortality and is not affected by misspecification of cause of death. We aimed to describe how health and demographic factors were associated with excess mortality during, compared to before, the pandemic. METHODS AND FINDINGS: We analysed a time series dataset including 9,635,613 adults (≥40 years old) registered at United Kingdom general practices contributing to the Clinical Practice Research Datalink. We extracted weekly numbers of deaths and numbers at risk between March 2015 and July 2020, stratified by individual-level factors. Excess mortality during Wave 1 of the UK pandemic (5 March to 27 May 2020) compared to the prepandemic period was estimated using seasonally adjusted negative binomial regression models. Relative rates (RRs) of death for a range of factors were estimated before and during Wave 1 by including interaction terms. We found that all-cause mortality increased by 43% (95% CI 40% to 47%) during Wave 1 compared with prepandemic. Changes to the RR of death associated with most sociodemographic and clinical characteristics were small during Wave 1 compared with prepandemic. However, the mortality RR associated with dementia markedly increased (RR for dementia versus no dementia prepandemic: 3.5, 95% CI 3.4 to 3.5; RR during Wave 1: 5.1, 4.9 to 5.3); a similar pattern was seen for learning disabilities (RR prepandemic: 3.6, 3.4 to 3.5; during Wave 1: 4.8, 4.4 to 5.3), for black or South Asian ethnicity compared to white, and for London compared to other regions. Relative risks for morbidities were stable in multiple sensitivity analyses. However, a limitation of the study is that we cannot assume that the risks observed during Wave 1 would apply to other waves due to changes in population behaviour, virus transmission, and risk perception. CONCLUSIONS: The first wave of the UK COVID-19 pandemic appeared to amplify baseline mortality risk to approximately the same relative degree for most population subgroups. However, disproportionate increases in mortality were seen for those with dementia, learning disabilities, non-white ethnicity, or living in London

Optimization of plates reinforced with different initial slope and variable number of carbon fibers

Optimization methods for curvilinear reinforcements placement aims to improve mechanical response of structure. Whenever a gradient-based method is used to optimization, it is necessary arbitrate an initial placement for the fibers. This initial guess has influence on the result. This work aims to observe the influence of the initial positioning of straight carbon fiber in epoxy resin plates, which had their compliance minimized by Sequential Linear Programming. The maximum displacement is observed too, even if it is not an objective function. The case studies were carried out on the same structure and the number of fibers and its slope were changed. Variation of the force slope was also evaluated. The results confirmed an influence of the initial slope in results. The addition of a greater number of fibers does not always cause a better performance in the design. To achieve the best results, it is essential that the initial arrangement be configured in such a way as to provide proximity of the ends of the fibers and the forces and supports. It's important to try to place the fibers with axial directions close to the axial direction of the force

Teoremas de ponto fixo e aplicações

In this work we will study some theories in other to obtain some classics fixed point theorems such as Banach Fixed Point Theorem, Brouwer Fixed Point Theorem and the Schauder Fixed Point Theorem. Our objective with this is to use these results to obtain solutions for certain ordinary and partial differential equation. In order to obtain these solution we develop specific methods using fixed point.Neste trabalho estudaremos certas teorias afim de obter alguns teoremas de ponto fixo clássicos tais como Teorema do Ponto Fixo de Banach, Teorema de Brouwer e o Teorema Schauder. Nosso objetivo com isto será utilizar tais resultados para obter soluções para certas equações diferenciais ordinárias e parciais. Afim de obter estas soluções desenvolveremos métodos específicos utilizando pontos fixos

Multi-objective optimization for building retrofit: a model using genetic algorithm and artificial neural network and an application

Retrofitting of existing buildings offers significant opportunities for improving occupants’ comfort and well-being, reducing global energy consumption and greenhouse gas emissions. This is being considered as one of the main approaches to achieve sustainability in the built environment at relatively low cost and high uptake rates. Although a wide range of retrofit technologies is readily available, methods to identify the most suitable set of retrofit actions for particular projects are still a major technical and methodological challenge. This paper presents a multi-objective optimization model using genetic algorithm (GA) and artificial neural network (ANN) to quantitatively assess technology choices in a building retrofit project. This model combines the rapidity of evaluation of ANNs with the optimization power of GAs. A school building is used as a case study to demonstrate the practicability of the proposed approach and highlight potential problems that may arise. The study starts with the individual optimization of objective functions focusing on building's characteristics and performance: energy consumption, retrofit cost, and thermal discomfort hours. Then a multi-objective optimization model is developed to study the interaction between these conflicting objectives and assess their trade-offs

Modified Verhulst-Solow model for long-term population and economic growths

In this study, we analyze the relationship between human population growth and economic dynamics. To do so, we present a modified version of the Verhulst model and the Solow model, which together simulate population dynamics and the role of economic variables in capital accumulation. The model incorporates support and foraging functions, which participate in the dynamic relationship between population growth and the creation and destruction of carrying capacity. The validity of the model is demonstrated using empirical data.Comment: 28 pages, 9 figures, Preprint Articl

O uso seletivo de classificadores binários na solução de problemas multirrótulos

Algumas tarefas de classificação permitem que exemplos pertençam a mais de uma classe simultaneamente, uma delas é chamada de classificação multirrótulo. Uma forma simples e eficiente de solucionar problemas desta natureza consiste em transformá-los em vários problemas binários e tratá-los independetemente. Em geral, o mesmo classificador base é usado para induzir os diversos modelos, sem considerar seu viés e as particularidades de cada conjunto binário. Todavia, nesse estudo, investigamos a hipótese de que utilizar o classificador adequado para cada conjunto binário melhora a classificação multirrótulo. Utilizando o método de transformação Binary Relevance, foi adotada uma estratégia de meta-aprendizado para recomendar o classificador adequado para cada subproblema. Os resultados experimentais validam a hipótese investigada e mostram o potencial da abordagem utilizada. Além disso, a estratégia proposta é genérica, de modo que, pode ser aplicada em outros problemas de transformação multirrótulo.FAPES

Socioeconomic inequalities in physiological risk biomarkers and the role of lifestyles among Russians aged 35-69 years.

BACKGROUND: Socioeconomic inequalities in cardiovascular (CVD) health outcomes are well documented. While Russia has one of the highest levels of CVD mortality in the world, the literature on contemporary socio-economic inequalities in biomarker CVD risk factors is sparse. This paper aims to assess the extent and the direction of SEP inequalities in established physiological CVD risk biomarkers, and to explore the role of lifestyle factors in explaining SEP inequalities in physiological CVD risk biomarkers. METHODS: We used cross-sectional data from a general population-based survey of Russians aged 35-69 years living in two cities (n = 4540, Know Your Heart study 2015-18). Logistic models were used to assess the associations between raised physiological risk biomarkers levels (blood pressure levels, cholesterol levels, triglycerides, HbA1C, and C-reactive protein) and socioeconomic position (SEP) (education and household financial constraints) adjusting for age, obesity, smoking, alcohol and health-care seeking behavior. RESULTS: High education was negatively associated with a raised risk of blood pressure (systolic and diastolic) and C-reactive protein for both men and women. High education was positively associated with total cholesterol, with higher HDL levels among women, and with low triglycerides and HbA1c levels among men. For the remaining risk biomarkers, we found little statistical support for SEP inequalities. Adjustment for lifestyle factors, and particularly BMI and waist-hip ratio, led to a reduction in the observed SEP inequalities in raised biomarkers risk levels, especially among women. High financial constraints were weakly associated with high risk biomarkers levels, except for strong evidence for an association with C-reactive protein (men). CONCLUSIONS: Notable differences in risk biomarkers inequalities were observed according to the SEP measure employed. Clear educational inequalities in raised physiological risk biomarkers levels, particularly in blood pressure and C-reactive protein were seen in Russia and are partly explained by lifestyle factors, particularly obesity among women. These findings provide evidence-based information on the need for tackling health inequalities in the Russian population, which may help to further contribute to CVD mortality decline