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Investigating Factors Influencing Students' Engagement in Sustainable Online Education
No full textDue to the COVID-19 pandemic, there has been a rapid shift from traditional classroom-based education to sustainable online classrooms. This has brought attention to the importance of comprehending the intricacies of students' engagement during virtual learning. Drawing upon the concept of community of inquiry in cognitive, social, and teaching presence, a mixed-methods approach involved data collected via a structured questionnaire administered to 452 university students to identify the factors that influence students' participation during online classes. Through the application of the CHAID (Chi-Squared Automatic Interaction Detection) decision tree algorithm, the quality of course content is identified as a cognitive predictor of students' engagement. It is worth mentioning that a significant proportion of students, specifically 61.7%, demonstrated a considerable degree of engagement with faculty content due to its high quality. With respect to the role of social presence, possession of a designated private space boost (69.2%) and requiring students to use their webcams are found to be critical for students' engagement. Lastly, teaching presence as a factor in enhancing students' engagement is demonstrated by promoting interactive classrooms and providing rapid feedback to students by teachers. The findings demonstrate the importance of teachers' quality course material, interactive classes, and the benefits of a physical environment free from distractions for optimizing students' engagement
Wallmapu-Araucanía in flames! An historical political ecology of fire in the domination of southern Chile
No full textThe conflict over Wallmapu-Araucan & iacute;a in southern Chile, between the Spanish conquistadores , the Chilean state and the Mapuche peoples, dates from the 16th century, with a key moment being the forced integration of Mapuche land into the Chilean state in the late nineteenth century. This paper discusses this long period of conflict in three moments: conquest, occupation and liberation, and it focuses on the use of fire as a politico -symbolic and techno-productive tool. A 'landscapes of power framework' is used for this historical political ecology analysis, based on texts from the nineteenth century to the present. The conclusions point to the historical importance of the use of fire as a tool not only for physical changes in the landscape, but principally as a tool of political symbolism that relates to a history of conflict of terror and displacement, used by the forces of occupation and resistance. (c) 2024 Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies
Evaluation of andean lupin (Lupinus mutabilis) seed meal as a dietary component on growth performance, feed utilization, nutrient digestibility, and liver histology of rainbow trout (Oncorhynchus mykiss) Juveniles
No full textThis study aimed to investigate the effects of dietary inclusion of Andean lupin (Lupinus mutabilis) on the growth performance, carcass composition, liver histology, and nutrient digestibility in rainbow trout (Oncorhynchus mykiss) juveniles. The experiment involved triplicate groups of fish (initial body weight 32.10 +/- 0.79 g) fed four extruded experimental diets with varying levels of Andean lupin (0, 50, 100, and 200 g kg(-1)) twice a day to apparent satiety over a period of 40 days. Faecal samples were collected daily for nutrient digestibility analysis. No significant correlations were observed between the dietary inclusion of Andean lupin and final weight, survival, weight gain, protein efficiency retention, thermal growth rate, feed conversion rate, and feed intake (P > 0.05). Similarly, there were no significant relationships between increasing dietary inclusion of Andean lupin and apparent digestibility coefficients for dry matter, crude protein, carbohydrate, and energy. However, the inclusion of Andean lupin led to a decrease in apparent digestibility coefficients for ash (R-2 =0.6, P 0.05). However, the hepatosomatic index decreased quadratically with increasing inclusion of Andean lupin (R-2 =0.51, P < 0.05), likely due to a slight reduction in cytoplasmic vacuolization of hepatocytes. In conclusion, this study demonstrates that Andean lupin is a promising plant protein ingredient for rainbow trout diets. It can be included at levels up to 200 g kg(-1) without adversely affecting growth performance and nutrient digestibility. These findings contribute to the expanding knowledge on alternative protein sources in aquaculture feed formulation
Preparation and extraction of chorion proteins from<i> Salmo</i><i> salar</i> embryos at the pigmented eye stage for electrophoresis with SDS-polyacrylamide gel
No full textThe chorion fulfills important functions in fish embryos, including protecting the embryo during development. The characterization of the protein profile of this envelope could be used as a bioindicator in the evaluation of the quality of embryonic development. The object of this work was to validate a standardized protocol for protein extraction from chorion of Salmo salar embryos at 280 accumulated thermal units (ATU) by comparing and combining existing methods. The protocol consists of consecutive washing of the chorion samples followed by protein extraction with the solution that was named SDS solution (Tris-HCl 100 mM (pH 8), Urea 8 M, 1% SDS, beta-mercaptoethanol 300 mM and EGTA 10 Mm, and 1% protease inhibitor cocktail) and mechanical methods. Protein extraction is enhanced by a working temperature of 75 degrees C and use of a disperser. The protein concentration was quantified by Bradford Assay. After extraction, the samples were diluted (dilution factor 10) before reading against the calibration curve. After gel electrophoresis with a load of 3 mu g of protein, staining showed more than 4 bands, with molecular weights between 25 kDa and 180 kDa. The protein profile of fish chorion was between 25 kDa and 180 kDa. Solution containing 1% SDS allows a higher extraction of proteins from the chorion of Atlantic salmon embryos with 280 ATU. Chorion protein identification is a valuable tool in determining gamete and embryo quality in fish
Paleoenvironmental and paleoclimatic dynamics of the Subtropical Andes of Argentina (35° S) during the last 3000 years
No full textThe most recent IPCC report indicated that the Subtropical Andes (32 degrees-35 degrees S) are one of the world areas undergoing a strong tendency towards more arid conditions due to current climate change. The winter precipitation that falls on the Andes, related to the Southern Westerlies System (SWS), is the main source of water for central Chile and west central Argentina, making it a fundamental socioeconomic resource. The few long-term records of the eastern slope of the Subtropical Andes do not permit establishing the long-term natural climate variability or determining if this trend does or does not respond to natural forcings. This study therefore presents a centennial and sub-centennial scale reconstruction of the paleoenvironmental dynamics of the eastern slope of the Subtropical Andes during the last 3000 cal yrs BP, based on the pollen record of the Laguna Coraz & oacute;n (LCO; 35.13 degrees S; 2200 m a.s.l.), in order to establish the different regional paleoenvironmental scenarios. The sedimentary record (182 cm) is mostly composed of laminated dark brown clay, and includes a 21-24 cm layer preliminarily associated with the 1932 AD eruption of the Quizap & uacute; volcano. The LCO record shows the development of a grass steppe associated with high-Andean shrubs between 3000 and 2440 cal yrs BP, suggesting slightly more humid conditions than present. From 2440 to 1110 cal yrs BP, there was continuous presence of the grass steppe along with high-Andean and Patagonian low shrubs, indicating moderately more humid conditions than today. The development of a grass steppe with low high-Andean shrubs from 1110 to 320 cal yrs BP reflects conditions slightly more humid that at present, showing a progressive decrease in humidity between 900 and 320 cal yrs BP. Since then, environmental conditions were similar to present ones, associated with the climatic variability at sub-centennial timescale. In the last 320 cal yrs BP, the record shows the presence of introduced species as a consequence of the occupation of the valley to raise livestock, and more recently, tourist activities. These environmental/climatic patterns are similar to those recorded for the western slope of the Subtropical Andes for the Late Holocene, indicating a regional forcing related to the winter precipitation associated with the SWS
Effects of the use of a cocoon on the autonomic, motor, and regulatory systems in preterm newborns: Randomized clinical trial
No full textIntroduction: The wrapping of the newborn in an orthopedic tubular mesh, simulating a cocoon, can allow the infant to regain the feeling of security and stability experienced in the uterus given that the movement of one of the parts of the body exerts tactile and pressure variation in others. Objective: We aimed to evaluate the influence of an orthopedic tubular mesh, simulating a cocoon, in therapeutic positioning, on the variables of the autonomous, motor, and regulatory systems of preterm newborns. Methods: A controlled and randomized clinical trial was conducted with preterm newborns positioned in dorsal decubitus and divided into two groups: (a) cocoon - newborns covered with an orthopedic tubular mesh, and (b) control - newborns positioned according to the sector's routine and without the use of an orthopedic mesh. During the follow-up, each newborn was placed in the position for 30 min and was recorded for a total of 2 min, once at the beginning and again at the end of the observation period. Variables related to the autonomous system (heart rate, respiratory rate, and peripheral oxygen saturation), motor system (general movements), and regulatory system (Neonatal Infant Pain Scale) were evaluated before and after the intervention. The videos were evaluated by a researcher blind to the purpose of the study, and the resulting data were analyzed using SPSS. Results: Of the 40 preterm newborns evaluated (32.5 1.83 weeks), 21 were female, and 20 were allocated to the cocoon group. The variables related to the autonomous, motor, and regulatory systems remained unchanged following the positioning in the cocoon, as compared to the typical positioning employed in the neonatal unit. Conclusion: The simulation of a cocoon, utilizing an orthopedic tubular mesh, when applied to preterm newborns admitted to a neonatal intensive care unit can contribute to maintaining low levels of stress, without altering variables of the autonomous, motor, and regulatory systems. (c) 2024 French Society of Pediatrics. Published by Elsevier Masson SAS. All rights reserved
Effects of Foliar Boron Application on Physiological and Antioxidants Responses in Highbush Blueberry (<i>Vaccinium corymbosum</i> L.) Cultivars
No full textBoron (B) is a micronutrient crucial for the growth, development, productivity, and quality of crops. However, in areas characterized by acid soil (pH(water) < 5.0) and high rainfall, soil B concentration tends to decrease, leading to insufficient supply to crops. This study was aimed at determining the optimal rate of B fertilization to enhance Vaccinium corymbosum L. performance in acid conditions. One-year-old cultivars with contrasting Al resistance (Al-sensitive Star and Al-resistant Cargo) were used. Plants were conditioned in plastic pots containing 18 L of half-ionic-strength Hoagland solution (pH 4.5) for 2 weeks. Thereafter, the following B treatments were applied foliarly: control, without B application (distilled water), 200, 400, and 800 mg L-1 of B as Solubor (R) for up to 72 h. Photosynthetic performance, root and shoot B levels, antioxidants, and oxidative stress were evaluated. Root and shoot B concentrations increased with the increasing B application, being higher in leaves than in roots of both cultivars. Net photosynthesis decreased at 800 mg L-1 B supply and effective quantum yield of PSII at 72 h in all B treatments. Lipid peroxidation increased in both cultivars at 800 mg L-1 B treatment. Antioxidant activity increased in all B treatments in both cultivars; while, at 400 and 800 mg L-1 B, total phenols increased in leaves of cultivar Star and decreased in cultivar Cargo. In conclusion, optimal B foliar application for highbush blueberry appears to be around 400 mg L-1 B. The appropriate B foliar application could help mitigate potential stress-induced problems in highbush blueberry cultivation. However, the optimal foliar B application should be confirmed in field experiments to help the farmers manage B nutrition
Acid Hydrothermal Amendment of Grape Wine Pomace: Enhancement of Phenol and Carbohydrate Co-Solubilization
No full textByproducts from the winery industry contain many bioactive compounds that are considered high-value-added compounds. White grape pomace (GP) is rich in carbohydrates; consequently, it can be used as a raw material for subsequent bioprocesses. In the present study, low-temperature hydrothermal treatments were carried out using different operational conditions regarding temperature (65-95 & DEG;C), time (120-240 min), and sulfuric acid addition at various concentrations (5-15% v/v). The results showed that by using a temperature of 65 & DEG;C, a period of 120 min, and 15% (v/v) of H2SO4, it was possible to obtain a liquid phase rich in phenols and carbohydrates, with total phenol compounds corresponding to 2113 & PLUSMN; 140 mg of gallic acid/kg GP and composed mainly of 3-hydroxytyrosol (1330 & PLUSMN; 22 mg/kg GP). In parallel, carbohydrate solubilization reached 245 g glucose/kg GP. These results demonstrate the promising potential of hydrothermally treated grape pomace as raw material for biorefinery processes
