This paper presents a solution chemistry-focused analysis of orthorhombic and cubic tricalcium aluminate (orth-C 3 A and cub-C 3 A, respectively) hydration. It is shown that the different solubilities of cub-and orth-C 3 A influence the bulk aqueous Ca to Al concentration ratio and the C 3 A/solution interface chemistry. The results are consistent with the bulk solution chemistry controlling orth-C 3 A dissolution, and with cub-C 3 A dissolution controlled by the formation of an Al-rich leached layer and adsorption of Ca-sulfur ion pair complexes onto this layer. The polynaphthalene sulfonate-based admixture used here is identified to modify the solution chemistry and retard cub-C 3 A dissolution. Strategies to inhibit C 3 A dissolution in Portland cement are discussed.
Resumo Objetivou-se estudar a associação entre padrão alimentar, fatores demográficos, socioeconômicos e o ambiente alimentar em uma população de adultos e idosos de uma cidade do Sul do Brasil. Estudo transversal com pessoas de ambos os sexos e idade entre 20 e 70 anos. Os padrões alimentares foram identificados por meio da análise de componentes principais. A regressão de Poisson foi utilizada para estimar as razões de prevalência brutas e ajustadas e os intervalos de 95% de confiança (IC 95%). Quatro padrões alimentares foram identificados: saudável, tradicional, carboidratos e açúcares refinados e fast food. Encontraram-se associações positivas entre: sexo feminino e maior renda com o padrão alimentar saudável; cor da pele preta ou parda e domicílios com seis ou mais moradores com padrões alimentares tradicional e carboidratos e açúcares refinados; maior escolaridade com o padrão fast food. Realizar as principais refeições em casa associou-se ao padrão tradicional, e almoço ou jantar fora do domicílio com os padrões carboidratos e açúcares refinados e fast food. Posição socioeconômica mais baixa leva ao maior consumo do padrão alimentar tradicional e/ou rico em carboidratos e açúcares, e uma posição socioeconômica mais elevada parece permitir uma escolha entre padrão saudável ou fast food.
The prevalence of overweight in Brazilian adults has grown in recent years. There is evidence indicating that environmental factors, especially social characteristics, may be involved in the aetiology of overweight, but few studies have investigated this association adequately. The main objective of this study was to identify residents’ perception of their social environment (social cohesion, security and violence) and assess its relationship with overweight in a central area of Porto Alegre, Brazil. The associations between socioeconomic characteristics and social environment perception were also explored. This cross-sectional study conducted in 2018–19 had 400 participants aged from 20 to 70 years living in low- and high-income areas of the city of Porto Alegre. Participants’ perception of social cohesion, security and violence were evaluated using a validated questionnaire. Participants’ body mass index (BMI) was measured, and those with a BMI ≥25 kg/m2 were considered to be overweight. Unadjusted and adjusted prevalence ratios (PRs) and 95% confidence intervals (95% CIs) were estimated through Poisson regression analysis; level of significance was 5%. The prevalence of overweight in the sample was 68.8% (95% CI 64.0–73.2). Individuals with a more positive social cohesion perception had a higher prevalence of overweight (PR 1.06; 95% CI: 1.00–1.12; p=0.02) than those with a less positive perception. Brown individuals also had a higher prevalence of overweight (PR: 1.08; 95% CI: 1.02–1.15; p=0.03) than those of other skin colour/race. No association was found between overweight and perception of security or violence. Therefore, social cohesion may be an important factor in overweight and the findings highlight the importance of considering social factors, and their perceptions, when planning actions for the prevention and control of overweight in a population.
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