Academic student satisfaction and perceived performance in the e-learning environment during the COVID-19 pandemic: Evidence across ten countries

The outbreak of the COVID-19 pandemic has dramatically shaped higher education and seen the distinct rise of e-learning as a compulsory element of the modern educational landscape. Accordingly, this study highlights the factors which have influenced how students perceive their academic performance during this emergency changeover to e-learning. The empirical analysis is performed on a sample of 10,092 higher education students from 10 countries across 4 continents during the pandemic’s first wave through an online survey. A structural equation model revealed the quality of e-learning was mainly derived from service quality, the teacher’s active role in the process of online education, and the overall system quality, while the students’ digital competencies and online interactions with their colleagues and teachers were considered to be slightly less important factors. The impact of e-learning quality on the students’ performance was strongly mediated by their satisfaction with e-learning. In general, the model gave quite consistent results across countries, gender, study fields, and levels of study. The findings provide a basis for policy recommendations to support decision-makers incorporate e-learning issues in the current and any new similar circumstances.info:eu-repo/semantics/publishedVersio

Higher education students’ achievement emotions and their antecedents in e-learning amid COVID-19 pandemic: A multi-country survey

The outbreak of the COVID-19 pandemic has had a wide range of negative consequences for higher education students. We explored the generalizability of the control-value theory of achievement emotions for e-learning, focusing on their antecedents. We involved 17019 higher education students from 13 countries, who completed an online survey during the first wave of the pandemic. A structural equation model revealed that proximal antecedents (e-learning self-efficacy, computer self-efficacy) mediated the relation between environmental antecedents (cognitive and motivational quality of the task) and positive and negative achievement emotions, with some exceptions. The model was invariant across country, area of study, and gender. The rates of achievement emotions varied according to these same factors. Beyond their theoretical relevance, these findings could be the basis for policy recommendations to support stakeholders in coping with the challenges of e-learning and the current and future sequelae of the pandemic.info:eu-repo/semantics/publishedVersio

Unexplored olive cultivars from the Valencian Community (Spain): some chemical characteristics as a valorization strategy

[EN] The olive processing industry has till date been dominated by a small group of cultivars, leading to the possibility of some olive cultivars becoming extinct in the near future. In this study, we determined the composition of some chemical components in the olive oils from 31 minor olive cultivars of the Valencian Community. Our main aim was to identify suitable cultivars, which could produce differentiated olive oils, thus aiming towards their valorization. The average oil content of minor olive cultivars was found to be good, with some of them reporting approximately 60% (dry basis). On average, the total phenolic content was 229mg kg(-1), with cv. Mas Blanc reporting the highest content (570mg kg(-1)). Among the various tocopherols found in olives, -tocopherol was the main constituent, with a maximum concentration of 290.6mg kg(-1). Linoleic acid was the main polyunsaturated fatty acid and varied between 3.4% (cv. Del Pomet) and 16.9% (cv. Blanqueta Enguera). Special attention needs to be paid to the composition of sterols, since some olive oils exceeded the limits established for some sterols by the current European legislation. Some of the cultivars studied were highly productive, and originated differentiated olive oils with a rich composition of antioxidants and essential fatty acids. In some cases, these beneficial compounds were higher than those of commercial oils obtained from the most common cultivars worldwide. These results could contribute to the commercial exploitation of some of the studied cultivars.Salazar-García, DC.; Malheiro, R.; Pereira, JA.; López- Cortés, I. (2019). Unexplored olive cultivars from the Valencian Community (Spain): some chemical characteristics as a valorization strategy. European Food Research and Technology. 245(2):325-334. https://doi.org/10.1007/s00217-018-3164-7S3253342452Avidan B, Birger R, Abed-El-Hadi F, Salmon O, Hekster O, Friedman Y, Lavee S (2011) Adopting vigorous olive cultivars to high density hedgerow cultivation by soil applications of uniconazole, a gibberellin synthesis inhibitor. Span J Agric Res 9:821–830Barranco D, Rallo L (2000) Olive cultivars in Spain. HortTechnology 10:107–110Navero DB (2000) World catalogue of olive varieties. International Olive Oil Council, MadridBorges TH, Pereira JA, Cabrera-Vique C, Lara L, Oliveira AF, Seiquer I (2017) Characterization of Arbequina virgin olive oils produced in different regions of Brazil and Spain: physicochemical properties, oxidative stability and fatty acid profile. Food Chem 215:454–462Laroussi-Mezghani S, Le Dréau Y, Molinet J, Hammami M, Grati-Kamoun N, Artaud J (2016) Biodiversity of Tunisian virgin olive oils: varietal origin classification according to their minor compounds. Eur Food Res Technol 242:1087–1099Kosma I, Vavoura M, Kontakos S, Karabagias I, Kontominas M, Apostolos K, Badeka A (2016) Characterization and classification of extra virgin olive oil from five less well-known Greek olive cultivars. J Am Oil Chem Soc 93:837–848Reboredo-Rodríguez P, González-Barreiro C, Cancho-Grande B, Valli E, Bendini A, Toschi TG, Simal-Gandara J (2016) Characterization of virgin olive oils produced with autochthonous Galician varieties. Food Chem 212:162–171Kyçyk O, Aguillera MP, Gaforio JJ, Jiménez A, Beltrán G (2016) Sterol composition of virgin olive oil of forty-three olive cultivars from the World Collection Olive Germplasm Bank of Cordoba. J Sci Food Agric 96:4143–4150Ruiz-Domínguez ML, Raigón MD, Prohens J (2013) Diversity for olive oil composition in a collection of varieties from the region of Valencia (Spain). 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J Am Oil Chem Soc 60:1524–1528Sousa A, Casal S, Malheiro R, Lamas H, Bento A, Pereira JA (2015) Aromatized olive oil: Influence of flavouring in quality, composition, stability, antioxidants, and antiradical potential. LWT Food Sci Technol 60:22–28Limón P, Malheiro R, Casal S, Acién-Fernández FG, Fernández-Sevilla JM, Rodrigues N, Cruz R, Bermejo R, Pereira JA (2015) Improvement of stability and carotenoids fraction of virgin olive oil by addition of microalgae Scenedesmus almeriensis extracts. Food Chem 175:203–211Motilva MJ, Tovar MJ, Romero MP, Alegre S, Girona J (2000) Influence of regulated deficit irrigation strategies applied to olive trees (Arbequina cultivar) on oil yield and oil composition during the fruit ripening period. J Sci Food Agric 80:2037–2043Palese AM, Nuzzo V, Favati F, Pietrafesa A, Celano G, Xiloyannis C (2010) Effects of water deficit on the vegetative response, yield and oil quality of olive trees (Olive europaea L., cv Coratina) grown under intensive cultivation. Sci Hortic 125:222–229Allalout A, Krichèn D, Methenni K, Taamalli A, Oueslati I, Daoud D, Zarrouk M (2009) Characterization of virgin olive oil from Super Intensive Spanish and Greek varieties grown in northern Tunisia. Sci Hortic 120:77–83Simopoulos AP, DiNicolantonio JJ (2016) The importance of a balanced ω-6 to ω-3 ratio in the prevention and management of obesity. Open Heart 3:e000385Marongui B, Özcan MM, Rosa A, Dessi MA, Piras A, AlJuhaimi F (2015) Monitoring of the fatty acid compositions of some olive oils. Riv Ital Sostanze Grasse 92:39–42Paiva-Martins F, Kiritsakis A (2017) Olive fruit and olive oil composition and their functionalcompounds. In: Kiritsakis A, Shahidi F (eds) Olives and olive oil as functional foods. Bioactivity, chemistry and processing. Wiley, Hoboken, pp 81–116Shahzad N, Khan W, Shadab MD, Ali A, Saluja SS, Sharma S, Al-Allaf FA, Abduljaleel Z, Ibrahim IAA (2017) Phytosterols as a natural anticancer agent: current status and future perspective. Biomed Pharmacol 88:786–794Covas MI, Ruiz-Gutiérrez V, de la Torre R, Kafatos A, Lamuela-Raventós RM, Osada J, Owen RW, Visioli F (2006) Minor components of olive oil: evidence to date of health benefits in humans. Nutr Rev 64:S20–S30Pirodi M, Albini A, Fabiani R, Giovannelli L, Luceri C, Natella F, Rosignoli P, Rossi T, Taticchi A, Servili M, Galli F (2017) Nutrigenomics of extra-virgin olive oil: a review. Biofactors 43:17–41Franco MN, Galeano-Díaz T, Sánchez J, De Miguel C, Martín-Vertedor D (2014) Total phenolic compounds and tocopherols profiles of seven olive oil varieties grown in the South-West of Spain. J Oleo Sci 63:115–125Aparicio R, Roda L, Albi MA, Gutiérrez F (1999) Effect of various compounds on virgin olive oil stability measured by Rancimat. J Agric Food Chem 47:4150–4155Bullota S, Celano M, Lepore SM, Montalcini T, Pujia A, Russo D (2014) Beneficial effects of the olive oil phenolic components oleuropein and hydroxytyrosol: focus on protection against cardiovascular and metabolic diseases. J Transl Med 12:1–9Krychene D, Salvador MD, Fregapane G (2015) Stability of virgin olive oil phenolic compounds during long-term storage (18 months) at temperatures of 5–50 °C. J Agric Food Chem 63:6779–6786Aparicio-Ruiz R, García-González DL, Oliver-Pozo C, Tena N, Morales MT, Aparicio A (2016) Phenolic profile of virgin olive oils with and without sensory defects: oils with non-oxidative defects exhibit a considerable concentration of phenols. Eur J Lipid Sci Technol 118:299–307Yorulmaz A, Poyrazoğlu ES, Özcan MM, Tekin A (2012) Phenolic profiles of Turkish olives and olive oils. 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Archaeogenetic analysis of Neolithic sheep from Anatolia suggests a complex demographic history since domestication

Sheep were among the first domesticated animals, but their demographic history is little understood. Here we analyzed nuclear polymorphism and mitochondrial data (mtDNA) from ancient central and west Anatolian sheep dating from Epipaleolithic to late Neolithic, comparatively with modern-day breeds and central Asian Neolithic/Bronze Age sheep (OBI). Analyzing ancient nuclear data, we found that Anatolian Neolithic sheep (ANS) are genetically closest to present-day European breeds relative to Asian breeds, a conclusion supported by mtDNA haplogroup frequencies. In contrast, OBI showed higher genetic affinity to present-day Asian breeds. These results suggest that the east-west genetic structure observed in present-day breeds had already emerged by 6000 BCE, hinting at multiple sheep domestication episodes or early wild introgression in southwest Asia. Furthermore, we found that ANS are genetically distinct from all modern breeds. Our results suggest that European and Anatolian domestic sheep gene pools have been strongly remolded since the Neolithic

Single-molecule kinetics of pore assembly by the membrane attack complex

The membrane attack complex (MAC) is a hetero-oligomeric protein assembly that kills pathogens by perforating their cell envelopes. The MAC is formed by sequential assembly of soluble complement proteins C5b, C6, C7, C8 and C9, but little is known about the rate-limiting steps in this process. Here, we use rapid atomic force microscopy (AFM) imaging to show that MAC proteins oligomerize within the membrane, unlike structurally homologous bacterial pore-forming toxins. C5b-7 interacts with the lipid bilayer prior to recruiting C8. We discover that incorporation of the first C9 is the kinetic bottleneck of MAC formation, after which rapid C9 oligomerization completes the pore. This defines the kinetic basis for MAC assembly and provides insight into how human cells are protected from bystander damage by the cell surface receptor CD59, which is offered a maximum temporal window to halt the assembly at the point of C9 insertion