viernes, 27 de mayo de 2022

Effects of waste glass powder as pozzolanic cement supplementary material for structural elements

The ever-growing global production of glass generates high waste percentages, the vast majority of which does not get recycled hence increasing the concern on its environmental impact. Studies on the pozzolanic properties of glass powder emerged as a solution to the abundance of waste glass powder available and its insufficient recycling. The aim of this study is to investigate the influence 10%,15% and 20% of waste soda-lime glass powder as partial cement replacement; fresh concrete tests were carried out, as well as compression strength tests at 28 days on grade 280 kg/cm2 concrete produced with pozzolanic cement. Tests results show an insignificant reduction of slump on the concrete mixes, an increase of air content and a decrease in density and compressive strength resistance with increasing glass powder substitution. 

Editorial: Trans Tech Publications Ltd
Journal: Materials Science Forum
DOI: http://doi.org/10.4028/p-4vq485
Enlaces adicionales: https://www.scientific.net/MSF.1058.127

martes, 24 de mayo de 2022

Análisis bibliométrico de la producción científica latinoamericana sobre COVID-19

Resumen: 

Introducción. La propagación de la COVID-19, una enfermedad infecciosa causada por el nuevo coronavirus SARS-CoV-2, se ha convertido en una pandemia que, a la par de su rápida diseminación a nivel mundial, ha traído consigo un aumento exponencial de la cantidad de estudios relacionados con el tema, fenómeno en el que los investigadores de Latinoamérica han participado activamente. 

Objetivo. Llevar a cabo un estudio bibliométrico descriptivo para identificar las tendencias de la investigación sobre COVID-19 producida en Latinoamérica. Materiales y métodos. Se recurrió a las bases de datos Web of Science, Scopus y Pubmed para recuperar la producción científica latinoamericana sobre COVID-19. Se analizaron los indicadores bibliométricos de producción, visibilidad, impacto y colaboración para evaluar la participación regional en la investigación sobre el tema. 

Resultados. El análisis de 142 documentos evidenció un crecimiento exponencial de la producción científica en el corto periodo analizado, una significativa colaboración internacional (51,4 %), y el liderazgo de las instituciones regionales (71 %) en la investigación con aportes en revistas de alta visibilidad, especialmente de Colombia, Brasil y México. Conclusiones. El estudio evidenció resultados relevantes sobre la participación regional en la investigación sobre COVID-19, no solo en cuanto a la cantidad y el crecimiento exponencial, sino también a su calidad y excelencia, con una elevada tasa de colaboración internacional y de publicación en revistas de reconocido prestigio, lo que, además de ser clave para la visibilidad de los países, es un considerable aporte a las investigaciones que se realizan en otros contextos geográficos.


Journal: Biomédica

DOI: https://doi.org/10.7705/biomedica.5571

URL: http://hdl.handle.net/10757/652160

Fecha: 2020-05-28



An Evaluation of the COVID-19 Pandemic and Perceived Social Distancing Policies in Relation to Planning, Selecting, and Preparing Healthy Meals: An Observational Study in 38 Countries Worldwide

Abstract: Objectives: To examine changes in planning, selecting, and preparing healthy foods in relation to personal factors (time, money, stress) and social distancing policies during the COVID-19 crisis. Methods: Using cross-sectional online surveys collected in 38 countries worldwide in April-June 2020 (N = 37,207, Mage 36.7 SD 14.8, 77% women), we compared changes in food literacy behaviors to changes in personal factors and social distancing policies, using hierarchical multiple regression analyses controlling for sociodemographic variables. Results: Increases in planning (4.7 SD 1.3, 4.9 SD 1.3), selecting (3.6 SD 1.7, 3.7 SD 1.7), and preparing (4.6 SD 1.2, 4.7 SD 1.3) healthy foods were found for women and men, and positively related to perceived time availability and stay-at-home policies. Psychological distress was a barrier for women, and an enabler for men. Financial stress was a barrier and enabler depending on various sociodemographic variables (all p < 0.01). Conclusion: Stay-at-home policies and feelings of having more time during COVID-19 seem to have improved food literacy. Stress and other social distancing policies relate to food literacy in more complex ways, highlighting the necessity of a health equity lens.

DOI: https://doi.org/10.3389/fnut.2020.621726
Journal: Frontiers in Nutrition
URL: http://hdl.handle.net/10757/657330
Fecha: 2021-02-04

Association of types of dietary fats and all-cause and cause-specific mortality: A prospective cohort study and meta-analysis of prospective studies with 1,148,117 participants

Abstract: Associations between dietary fats and mortality are unclear. Methods: We evaluated the relationship between quartiles of total fat, mono-unsaturated (MUFA), polyunsaturated (PUFA) and saturated fatty acid (SFA) consumption, and all-cause, coronary heart disease (CHD), stroke, and type 2 diabetes (T2D)-associated mortality in 24,144 participants from the National Health and Nutrition Examination Surveys (NHANES) 1999–2010. We added our results to a meta-analysis based on searches until November 2018. Results: In fully adjusted Cox-proportional hazard models in our prospective study, there was an inverse association between total fat (HR: 0.90, 95% confidence interval 0.82, 0.99, Q4 vs Q1) and PUFA (0.81, 0.78–0.84) consumption and all-cause mortality, whereas SFA were associated with the increased mortality (1.08, 1.04–1.11). In the meta-analysis of 29 prospective cohorts (n = 1,148,117) we found a significant inverse association between total fat (0.89, 0.82–0.97), MUFA (0.93, 0.87–0.99) and PUFA (0.86, 0.80–0.93) consumption and all-cause mortality. No association was observed between total fat and CVD (0.92, 0.79–1.08) or CHD mortality (1.03 0.99–1.09). A significant association between SFA intake and CHD mortality (1.10, 1.01–1.20) was observed. Neither MUFA nor PUFA were associated with CVD or CHD mortality. Inverse associations were observed between MUFA (0.80, 0.67–0.96) and PUFA (0.84, 0.80–0.90) intakes and stroke mortality. Conclusions: We showed differential associations of total fat, MUFA and PUFA with all-cause mortality, but not CVD or CHD mortalities. SFA was associated with higher all-cause mortality in NHANES and with CHD mortality in our meta-analysis. The type of fat intake appears to be associated with important health outcomes.


Journal: Clinical Nutrition



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The Peru approach against the COVID-19 infodemic: Insights and strategies

Abstract: The COVID-19 epidemic has spawned an "infodemic,"with excessive and unfounded information that hinders an appropriate public health response. This perspective describes a selection of COVID-19 fake news that originated in Peru and the government's response to this information. Unlike other countries, Peru was relatively successful in controlling the infodemic possibly because of the implementation of prison sentences for persons who created and shared fake news. We believe that similar actions by other countries in collaboration with social media companies may offer a solution to the infodemic problem.