Asociación entre nivel de actividad física y ambiente construido (accesibilidad, infraestructura y seguridad) en ocho países de Latinoamérica : estudio de corte-transversal

Introduction: Approximately 60% of people around the world do not perform the physical activity necessary to maintain adequate health (WHO, 2016). The aim of this study is to find the relationship between the physical activity level of the population between 15 and 65 years old living in urban areas of eight Latin American countries -Argentina, Brazil, Chile, Colombia, Costa Rica, Ecuador, Peru and Venezuela- and the built environment of these areas...Introducción: Aproximadamente 60% de las personas alrededor del mundo no realizan la actividad física necesaria para mantener una salud adecuada (OMS, 2016). El objetivo de este estudio es determinar la relación entre el nivel de actividad física de la población entre 15 y 65 años residentes en áreas urbanas de ocho países de Latinoamérica -Argentina, Brasil, Chile, Colombia, Costa Rica, Ecuador, Perú y Venezuela- y el ambiente construido de estas zonas..

Understanding the Surface Chemistry of SnO₂ Nanoparticles for High Performance and Stable Organic Solar Cells

In organic solar cells, the interfaces between the photoactive layer and the transport layers are critical in determining not only the efficiency but also their stability. When solution-processed metal oxides are employed as the electron transport layer, the presence of surface defects can downgrade the charge extraction, lowering the photovoltaic parameters. Thus, understanding the origin of these defects is essential to prevent their detrimental effects. Herein, it is shown that a widely reported and commercially available colloidal SnO2 dispersion leads to suboptimal interfaces with the organic layer, as evidenced by the s-shaped J–V curves and poor stability. By investigating the SnO2 surface chemistry, the presence of potassium ions as stabilizing ligands is identified. By removing them with a simple washing with deionized water, the s-shape is removed and the short-circuit current is improved. It is tested for two prototypical blends, TPD-3F:IT-4F and PM6:L8:BO, and for both the power conversion efficiency is improved up to 12.82% and 16.26%, from 11.06% and 15.17% obtained with the pristine SnO2, respectively. More strikingly, the stability is strongly correlated with the surface ions concentration, and these improved devices maintain ≈87% and ≈85% of their initial efficiency after 100 h of illumination for TPD-3F:IT-4F and PM6:L8:BO, respectively.</p

Association between built environment and physical activity in Latin American countries: a multicentre cross-sectional study

Abstract Objective: To assess the association between the physical activity level and the built environment by accessibility, microinfrastructure and security in Latin America (LA). Design: We conducted a multicentre cross-sectional study to collect physical activity and built environment data. The levels of physical activity were calculated through the International Physical Activity Questionnaire survey. Using the Neighbourhood Environment Walkability Scale-Abbreviated, characteristics of the built environment were measured through three domains: accessibility, microinfrastructure and security. To estimate the association of the built environment and physical activity, we used mixed effects logistic regression analysis. In addition, likelihood ratio test to account for clustered effect within countries and/or cities was used. Setting: Eight countries in LA. Participants: Adults aged 15-65 years (n=9218) living in urban areas and consented to participate of the Latin American Study of Nutrition and Health. Results: Most of the population in LA had access to a grocery store (97.2%), public transport stop (91.5%) and children's playground (81.6%). Metropolitan parks were more accessible in Ecuador (59.8%) and Colombia (59.2%) than in Venezuela (33.5%). Individuals located within 20 min of walking from sport facilities or children's playground areas were more likely to perform moderate-to-high physical activity OR 1.20 (95% CI 1.06 to 1.36) and OR 1.25 (95% CI 1.02 to 1.53), respectively. Only 14.5% of the population from the region considered that their neighbourhood had an adequate design for walking or cycling. Likewise, among adults living in LA, only 39.75% had the perception of living in a safe neighbourhood. Conclusions: This multicentre study shows that currently, LA built environment does not promote physical activity in the region. Our findings provide the rationale to push forward, at regional and national levels, policies and interventions that will help to achieve a safe, healthy and friendly built environment to encourage participation in active recreation and sports in leisure time.Coca Cola Company/[]//Estados UnidosHospital Infantil Sabará/[]//BrazilInternational Life Science Institute/[]/ILSI/ArgentinaUniversidad de Costa Rica/[]/UCR/Costa RicaPontificia Universidad Católica de Chile/[]//ChilePontificia Universidad Javeriana/[]//ColombiaUniversidad Central de Venezuela/[]/UCV/VenezuelaUniversidad San Francisco de Quito/[]//EcuadorInstituto de Investigación Nutricional de Perú/[]//PerúUCR::Vicerrectoría de Docencia::Salud::Facultad de Medicina::Escuela de Medicin