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Evaluation of Two Chilean Native Macroalgae: “Pelillo” (Gracilaria chilensis) and “Lamilla” (Ulva sp.) for Thermal Insulation Application
No full textEnergy consumption in the residential sector and air pollution are relevant topics for the global population. One of the causes, especially in cold climate cities, is that buildings maintain a high energy consumption for heating and cooling, primarily using low-efficiency biomass combustion for heating, which releases a significant amount of particulate matter into the environment. In this context, thermal insulation materials play a crucial role in reducing the energy demand of buildings, requiring advancements in the sustainable development of such materials within the context of climate change. This study carried out an evaluation of two algae species found along the Chilean coasts, with the aim of characterizing them and creating a prototype of a sustainable material. Their physicochemical properties were analyzed, and the results demonstrate that the algae exhibit excellent thermal insulation properties, with an average thermal conductivity of 0.036 [W/mK]. This result is comparable to expanded polystyrene (EPS), a widely used material in the Chilean and global markets, which has an average thermal conductivity value of 0.038 [W/mK]. Additionally, the algae show a good thermal stability, and their morphology contributes to the development of a bulk material, as they possess a porous structure with air chambers between the fibers. © 2023 by the authors.Universidad Autónoma de Chil
Análisis de la Morfología Interna y Externa del Primer Molar Mandibular en una Subpoblación Chilena Mediante Tomografía Computarizada de Haz Cónico
No full textThe mandibular first molar (MFM) commonly presents two roots with two canals in the mesial root and one or two canals in the distal root. However, morphological variations have been described in different populations, which must be considered when planning endodontic treatment. The aim of this study was to analyze the internal and external morphology of the MFM in a Chilean sub-population using cone-beam computed tomography (CBCT) images. An in vivo cross-sectional, descriptive, and observational study was conducted using CBCT exams from 351 right and left MFM. The data were analyzed by descriptive statistics using the Chi-Square test for categorical variables, Fisher’s exact test, the Mann-Whitney U non-parametric test for two independent samples, and the Wilcoxon non-parametric test for related samples. Of the total sample, 1 root was observed in 2.27 % of the cases, 2 roots in 93.73 %, and 3 roots in 4 %. In relation to the number of canals, 71.23 % of the MFM showed 3 root canals, 16.81 % 4 canals, 9.69 % 2 canals, and 2.28 % 1 canal. Of all the studied cases, 2.3 % had a C-shaped anatomy. In terms of morphology, using Zhang’s classification, variant 3 was observed in 71.23 %, variant 4 in 12.82 %, variant 1 in 9.67 %, variant 6 in 4 %, and variant 8 in 2.28 %. In conclusion, the morphology of the MFM is variable in a Chilean sub-population, and these variations must be considered before and during endodontic therapy. CBCT proved to be an effective tool for the in vivo study of tooth morphology. © 2023, Universidad de la Frontera. All rights reserved.Universidad de La Frontera, UFROUniversidad Autónoma de Chil
Structure and bonding of molecular stirrers with formula B7M2- and B8M2 (M = Zn, Cd, Hg) (vol 22, pg 12312, 2020)
No full textCorrection for 'Structure and bonding of molecular stirrers with formula B7M2- and B8M2 (M = Zn, Cd, Hg)' by Rui Yu et al., Phys. Chem. Chem. Phys., 2020, 22, 12312-12320, https://doi.org/10.1039/D0CP01603A
Encuesta Nacional de Percepción Social de la Inteligencia Artificial (ia)
No full textEl objetivo de la Encuesta Nacional de Percepción Social de la Inteligencia Artificial 2023 es recopilar información valiosa que permita conocer la manera en que la población chilena percibe la Inteligencia Artificial y se relaciona con sus aplicaciones en la vida cotidiana, además de analizar actitudes, conocimientos y opiniones respecto de la ia. A partir de esta investigación —y en línea con las recomendaciones sobre el uso ético de la ia unesco (2022)1 y la Política Nacional de Inteligencia Artificial (minciencia, 2021)2 —, como Centro de Comunicación de las Ciencias queremos aportar a la reflexión colectiva sobre ia y sugerir algunos elementos que pueden resultar valiosos para la comunidad científica y, especialmente, para los/as comunicadores/as de la ciencia y la tecnología
Muscle Quality Index in Morbidly Obesity Patients Related to Metabolic Syndrome Markers and Cardiorespiratory Fitness
No full textBackground: Muscle quality index (MQI) is an emerging health indicator obtained by dividing handgrip strength by body mass index (BMI) that needs to be studied in morbidly obese patients (defined by BMI ≥ 35 kg/m2). Objective: To determine the association between MQI, metabolic syndrome (MetS) markers, and cardiorespiratory fitness (CRF), and as a second objective to determine the potential mediation role of MQI in the relationship between abdominal obesity and systolic blood pressure (SBP) in this sample. Methods: This cross-sectional study included 86 severely/morbidly obese patients (age = 41.1 ± 11.9 y, nine men). MQI, metabolic syndrome markers, CRF, and anthropometric parameters were measured. Two groups were developed according to MQI; High-MQI (n = 41) and Low-MQI (n = 45). Results: The Low-MQI group reported higher abdominal obesity (High-MQI: 0.7 ± 0.1 vs. Low-MQI: 0.8 ± 0.1 WC/height; p = 0.011), SBP (High-MQI: 133.0 ± 17.5 vs. Low-MQI: 140.1 ± 15.1 mmHg; p = 0.048), and lower CRF (High-MQI; 26.3 ± 5.9 vs. Low-MQI; 22.4 ± 6.1 mL/kg/min, p = 0.003) than the High-MQI group. Waist-to-height ratio (β: −0.07, p = 0.011), SBP (β: −18.47, p = 0.001), and CRF (β: 5.21, p = 0.011) were linked to MQI. In a mediation model, the indirect effect confirms that MQI is a partial mediator of the association between abdominal obesity with SBP. Conclusions: MQI in morbidly obesity patients reported an inverse association with MetS markers and a positive association with CRF (VO2max). It mediates the relationship between abdominal obesity and SBP. © 2023 by the authors.Universidad Autónoma de Chil
Effects of different plyometric training frequencies on physical performance in youth male volleyball players: a randomized trial
No full textThis study aimed to analyze the effect of plyometric training (PT) at different frequencies on jump performance, running sprint speed, and service speed in youth male volleyball players. The participants were randomly assigned to one PT session per week (Experimental Group 1, EG1, n = 15), two PT sessions per week (Experimental Group 2, EG2, n = 14), and a control group (CG, n = 13). The total weekly jumping ranged between 98 and 196 jumps (equalized between, EG1 and, EG2). The assessments performed were squat jump (SJ), countermovement jump (CMJ), CMJ-arms, drop jump (DJ), 5-m sprint, 10-m sprint, and service speed. The intragroup comparisons showed that, EG1 significantly (p < 0.001) improved SJ (Δ = 12.74%; d = 1.30), CMJ (Δ = 11.94%; d = 1.71), CMJ-arms (Δ = 12.02%; d = 1.47), DJ (Δ = 10.93%; d = 1.30), 5-m sprint (Δ = −4.61%; d = 0.29), 10-m sprint (Δ = −3.95%; d = 0.40) and service speed (Δ = 8.17%; d = 1.53). Similarly, EG2 significantly (p˂ 0.001) improved SJ (Δ = 11.52%; d = 1.25), CMJ (Δ = 11.29%; d = 1.38), CMJ-arms (Δ = 11.42%; d = 1.26), DJ (Δ = 13.90%; d = 2.17), 5-m sprint (Δ = −3.85%; d = 0.25), 10-m sprint (Δ = −2.73%; d = 0.25) and service speed (Δ = 6.77%; d = 1.44). The CG significantly (p < 0.05) improved SJ (Δ = 2.68; d = 0.28), CMJ-arms (Δ = 2.30; d = 0.35), 5-m sprint (Δ = −1.27; d = 0.10) and service speed (Δ = 1.42; d = 0.30). Intergroup comparisons revealed significantly greater improvements in all variables (p < 0.001) in, EG1 and, EG2 concerning to CG. However, no significant differences were found between, EG1 and, EG2. A moderate weekly PT volume, distributed in one or two sessions per week, seems equally effective. Copyright © 2023 Hernandez-Martinez, Guzman-Muñoz, Ramirez-Campillo, Herrera-Valenzuela, Magnani Branco, Avila-Valencia, Luis Carter-Beltran, Aravena-Sagardia, Méndez-Cornejo and Valdés-Badilla.Universidad Autónoma de Chil
Which anthropometric equation to predict body fat percentage is more strongly associated with maximum oxygen uptake in adolescents? A cross-sectional study
No full textBACKGROUND: Identifying the relationship between maximum consumption of oxygen and body fat percentage is important due to increased cardiovascular risk factors. OBJECTIVE: This study aimed to verify the association between body fat percentage determined by three predictive equations using anthropometric measures (Lohman, Boileau, and Slaughter) and maximum oxygen uptake (VO2 max). We also aimed to estimate the capacity of these equations for explaining VO2 max variations in adolescents according to sex. DESIGN AND SETTING: This was a cross-sectional study conducted in high schools in São José, Southern Brazil. METHODS: This study included 879 adolescents (14–19 years) from Southern Brazil. Aerobic fitness was assessed using the modified Canadian Aerobic Fitness Test. The independent variable was body fat percentage predicted by the Lohman, Boileau, and Slaughter equations. Analyses adjusted for sociodemographic variables, physical activity level, and sexual maturation were performed with P value < 0.05. RESULTS: All anthropometric prediction equations used to estimate body fat percentage explained VO2 max variations in adolescents. In male adolescents, both regression models based on the Boileau et al.12 and Lohman10 equations revealed higher explanatory power for VO2 max (20%) compared with that based on the Slaughter et al.13 equation (19%). In female adolescents, the model based on the anthropo-metric equation of Slaughter et al.13 showed the greatest explanatory power for VO2 max (18%). CONCLUSION: The inverse relationship between VO2 max and body fat intensifies the need for effective intervention programs that prioritize maintenance of appropriate body fat and aerobic fitness levels be-cause inadequate levels of both factors result in negative health consequences. © 2023 by Associação Paulista de Medicina.Universidad Autónoma de Chil
Una Propuesta Educativa desde la Historia y el Medio Ambiente para el Tratamiento de un Tema Controversial, en el Aula Chilena: la Ocupación de la Araucanía, en la Segunda Mitad del Siglo XIX
No full textIn Chile, several investigations have been made in the last decade in the subdiscipline of environmental history. However, the same scenario does not seem to exist for education side of the matter. It is important to revert this situation if we want to take educational advantages in environmental history such as interculturality, more complex explanations of the past and interdisciplinarity. This work illustrates this educational potential through the Chilean occupation of the Araucanía region, in the second half of the nineteenth century. This theme was chosen for being one of the controversial topics in the Chilean history teaching that complicates teacher's job. To prepare the proposal, primary, secondary, and tertiary sources of different kinds have been analyzed qualitatively. A teaching of history is proposed from three thematic lines that, according to historian Donald Hughes, distinguish environmental history, namely: The impact that human beings have generated on the natural environment; the influences that this has had on the former; and the perceptions that human beings have had surrounding the environment. In this way, the teaching surrounding the occupation of the Araucanía gains greater coherence with the geographical and historical reality of the region. Even more importantly, citizens develop responsible attitudes towards nature and a greater awareness of their place in the world. © 2023 The authors.Universidad Autónoma de Chil
ESCASEZ HÍDRICA Y LETALIDAD POR COVID-19 EN ZONAS RURALES CHILENAS
No full textThe COVID-19 pandemic, caused by the spread of the SARS-CoV-2 virus around the world in March 2020, severely affected many areas of people's life and health. Among the main ways to prevent its spread is by washing hands and food with soap and water. However, the latter is scarce in several municipalities of Chile, highlighting the difficulties of water supply at a national level. This work investigates the relationship between municipalities decreed by the government as being in a situation of water scarcity and the COVID-19 mortality levels found in rural areas between March 2020 and June 2021. Statistical data were used from different databases to correlate mortality rates with the level of municipal development and access to a drinking water network. A negative correlation was obtained between high COVID-19 mortality and low levels of communal development and connection to the drinking water network. As a result, it is deemed necessary to take into account geographical variables, such as water scarcity, in the generation of public health policies and water resource management. © 2023 The Author(s).Universidad Autónoma de Chil
Differential effect of fisheries to the COVID-19 pandemic in the region of Andalusia (Spain)
No full textFishing is one of the most widespread and important human activities in coastal ecosystems and it plays a fundamental role in employment and the economy of coastal communities. However, in the period 2020–2021, the global outbreak of COVID-19 negatively affected fishing economic activity. Against this background, Andalusia (South of Spain) is an important region in which the resilience of different fishing exploitation systems can be studied, but within the same social and economic framework. Therefore, the main study aim was to investigate the resilience of fishing activity to the COVID-19 pandemic in two Andalusian fishing grounds (i.e. Atlantic and Mediterranean). We analysed daily landings and the first-sale prices of fresh fish of the most caught species in both fishing grounds, while taking into account the different seasonal behaviour of the fisheries. Generalised Linear Models were used to compare the data, which were obtained during periods in which the COVID-19 severity levels differed. These levels were implemented according to political measures. The final objective was to understand how the degree of industrialisation in the fleets can hinder or help maintain the economic activity of fisheries during major crises. © 2022 The AuthorsProyectos de I+D+I, (RETOS-PID2020-118097RB-I00); State Research Agency; Ministerio de Ciencia, Innovación y Universidades, MCIU; Ministerio de Ciencia e Innovación, MICINN; European Regional Development Fund, ERDFUniversidad Autónoma de Chil