Examining the endpoint impacts, challenges, and opportunities of fly ash utilization for sustainable concrete construction.

Fly ash has been widely used as a cement substitute to improve the sustainability of concrete. Although the advantages of fly ash have been extensively documented, there is a gap in understanding why its use in mass concrete applications remains low in some countries, such as the Philippines. Thus, this work aims to understand the issues that impede waste utilization, particularly fly ash in the concrete construction industry, quantify the impact of the current practice, and identify opportunities for sustainable fly ash utilization. Endpoint impact analysis was conducted through the life cycle using SimaPro 9.3 to quantify the impacts on human health, ecosystem, and resources of 31 concrete mixtures of low, normal, and high strength design with 0 to 20% fly ash as cement replacement. In-depth, semi-structured interviews with key stakeholders were undertaken to determine the institutional, economic, social, and technological challenges related to the utilization of waste materials in large-scale concrete construction. More than 90% of the total impact of concrete contributes to damage to human health, primarily caused by global warming and fine particulate matter. The use of fly ash at 20% replacement by weight of cement benefits resources more significantly than human health and the ecosystem. The use of chemical admixture to improve strength has a significant impact on resources. High fly ash replacement for normal and high-strength concrete has a greater reduction in all endpoint categories than for low-strength design. Recommendations are proposed to maximize the beneficial impact of using fly ash in the concrete industry.

Comparative environmental assessment of low and high CaO fly ash in mass concrete mixtures for enhanced sustainability: Impact of fly ash type and transportation.

The effect of fly ash type on the sustainability of concrete mixtures has yet to be quantified. This study aims to assess the environmental impacts of low calcium oxide (CaO) and high CaO fly ash in mass concrete mixtures from Thailand. The study analyzed 27 concrete mixtures with varying percentages of fly ash as a cement replacement (0%, 25%, and 50%) for 30 MPa, 35 MPa, and 40 MPa compressive strengths at specified design ages of 28 and 56 days. Sources of fly ash have been located between 190 km and 600 km away from batching plants. The environmental impacts were assessed using SimaPro 9.3 software. The global warming potential of concrete is reduced by 22-30.6% and 44-51.4% when fly ash, regardless of type, is used at 25% and 50%, respectively, in comparison with pure cement concrete. High CaO fly ash has more environmental benefits than low CaO fly ash when utilized as a cement substitute. The reduction in environmental burden was most significant for the midpoint categories of mineral resource scarcity (10.2%), global warming potential (8.8%), and water consumption (8.2%) for the 40 MPa, 56-day design with 50% fly ash replacement. The longer design age (56 days) for fly ash concrete showed better environmental performance. However, long-distance transport significantly affects ionizing radiation and ecotoxicity indicators for terrestrial, marine, and freshwater environments. Furthermore, the results show that a high cement replacement level (50%) may not always have a reduced environmental impact on mass concrete when considering long-distance transportation. The critical distance calculated based on ecotoxicity indicators was shorter than those calculated using global warming potential. The results of this study can provide insights for developing policies to increase concrete sustainability using different types of fly ash.

A systematic mapping literature review of education around sexual and gender diversities.

Education around sexual and gender identities is highly important to understand diversity and prevent discrimination, violence, and even murder. Nevertheless, educational institutions around the world are lacking a curriculum that explicitly includes diversity and acknowledges the LGBTQ+ community, a minority that over the years has been facing consequences from this exclusion. This study presents a detailed description of the process applied to analyze the studies using a systematic mapping literature review, as well as the positive results found from those educational institutions that started their path to inclusion around sexual and gender diversities through their curricula. The research questions targeted in this work are: What is being taught in educational institutions regarding sexual and gender diversities? What are the approaches used inside the classrooms to teach sexual and gender diversities? Which students are receiving education regarding sexual and gender diversities? Is there a technological approach and/or tool used to teach sexual and gender diversities? After applying the filtering processes, 69 studies were selected from five different online libraries: ACM, DOAJ, Lens.org, SCOPUS, and SpringerLink. The conclusions made from the findings of this review are that those studies that do tackle concerns around the topic have proven to benefit the LGBTQ+ community, the education around sexual and gender diversities predominates within the healthcare field, there are a lack of studies around this topic in Latin American countries, and technological tools are minimally used during the teaching processes.

Use of Robotic Platforms as a Tool to Support STEM and Physical Education in Developed Countries: A Descriptive Analysis.

The lack of interest of children at school is one of the biggest problems that Mexican education faces. Two important factors causing this lack of interest are the predominant methodology used in Mexican schools and the technology as a barrier for attention. The methodology that institutions have followed has become an issue because of its very traditional approach, with the professor giving all the theoretical material to the students while they listen and memorize the contents, and, if we add the issue of the growing access to technological devices for students, children carrying a phone are more likely to be distracted. This study aims to integrate technology through assistive robots as a beneficial tool for educators, in order to improve the attention span of students by making the learning process in multiple areas of the Mexican curriculum more dynamic, therefore obtaining better results. To prove this, four different approaches were implemented; three in elementary schools and one in higher education: the LEGO® robotic kit and the NAO robot for STEM (science, technology, engineering, and mathematics) teaching, the NAO robot for physical education (PE), and the PhantomX Hexapod, respectively. Each of these technological approaches was applied by considering both control and experimental groups, in order to compare the data and provide conclusions. Finally, this study proves that the attention span is indeed improved as a result of implementing robotic platforms during the teaching process, allowing the children to become more motivated during their PE class and become more proactive and retain more information during their STEM classes.

Estudio de los tejidos de moluscos Lymnaea truncatula y Lymnaea cubensis infectados por miracidios de Fasciola hepatica / Study of Lymnaea truncatula and Lymnaea cubensis mollusk tissues infected by Fasciola hepatica miracidia

En el presente trabajo se estudiaron las vías de penetración del miracidio de Fasciola hepática (Linnaeus, 1758) dentro del hepatopáncreas de Lymnaea truncatula (Müller, 1774) y Lymnaea cubensis (Pfeiffer, 1839), en 2 moluscos obtenidos de las zonas endémicas de Fasciolosis de Rusia y de la República Mexicana respectivamente¹. El trayecto de la larva mostró la disolución de la sustancia intercelular y deformación de células epiteliales de los tejidos de los moluscos. A nivel citológico se observaron cambios en el epitelio lineal de cobertura de los ductos de la glándula digestiva y en el tejido conjuntivo del hepatopáncreas. Se observaron diferencias en las vías de penetración y afectación en las dos especies de moluscos estudiados, marcando así las diferencias de las condiciones ecológicas que prevalecen en cada zona geográfica.

The present work investigated the penetration pathways of Fasciola hepática (Linnaeus, 1758) into the hepatopancreas of Lymnaea truncatula (Muller, 1774) and Lymnaea cubensis (Pfeiffer, 1839), two mollusks obtained from Fasciolosis endemic areas in Russia and Mexico, respectively. The larval trajectory showed dissolution of intercellular substance and deformation of epithelial cells of mollusk's tissues. Cytological changes in the ductal epithelium of the digestive gland and in the connective tissue of hepatopancreas were found. Some differences in the penetration and damage pathways in the two species of mollusks studied were observed; thus highlighting the differences in the environmental conditions prevailing in each geographic area.

[Cost/benefit of preoperative examinations for routine elective surgery]. / Costo-beneficio de los exámenes preoperatorios de rutina en cirugía electiva.

INTRODUCTION: Preoperative exams are a common practice for surgeons; however, their use is not based on a scientific or medical basis. In the best of scenarios, it is an institutional policy. MATERIAL AND METHODS: We wanted to determine the utility and cost-effectiveness ratio of of preoperative routine tests (PRT) and we analyzed retrospectively the frequency of complications, hospital stay, and cost-effectiveness of PRT, in subjects with no concomitant disease, who were having elective surgery performed by the general surgery service. We included 141 male and female subjects, ages from 18 to 40 years, during 2002. RESULTS: There was no increase in complication frequency in patients with PRT abnormalities (6.2% versus 5.1%, OR 0.82, p = 0.78), or hospital stay time (2.37 versus 2.76, p = 0.55). PRT were repeated in 19.1%, expiration being the most frequent reason (46%). Urinalysis was the most frequent abnormal test (21.4%). We found only five clinically relevant abnormalities (3.5%). Only three patients required therapeutic intervention prior to surgery. The detection cost for PRT abnormalities requiring preoperative medical intervention was 22,732 Mexican pesos (approximately USD 2,022). CONCLUSIONS: The use of PRT in young clinically healthy subjects is an expensive and inefficient practice.