Engagement in Online Learning Through the Lens of Adults' Learning Experience

The article aims to critically examine the role of engagement in the study of the educational experiences of adult learners in online learning. The authors highlight the existence of a gap between the nature of adult educational experiences and the lens through which these experiences are studied and evaluated. This lens is the learners' engagement. The authors highlight the complexity of the construct of learner engagement and point out the inadequacy of assessing it solely through behavioral markers. The theoretical framework of the article is the Community of Inquiry (CoI) model for studying the educational experiences of learners in the digital environment, based on the notion of the socially constructed nature of learning. The article shows how the idea of lifelong learning as the formation of a new professional identity of adults is consistent with the idea of an ontological turn in education. By conceptualizing the educational experiences of adults as active participants in the learning process, the authors propose to consider engagement as a characteristic of these experiences. The authors identify external and internal factors of learner engagement. Based on previous research, internal factors are proposed, namely learners’ prior experience, future self-image, and personal goals. External factors are based on the self-determination theory, where the needs for competence and belongingness become particularly salient for engagement in online learning

Utjecaj hranidbe s dodatkom trutovskog legla na folikulogenezu u nazimica

The biological properties of bee drone brood make it an ideal additive for growth promotion in animal husbandry instead of banned hormonal anabolics and antibiotics. However, the drone brood action on mammalian ovaries has not been well studied. The present study analyzes the impact of drone brood homogenate (DBH) in the diet of growing gilts on folliculogenesis. Large White female pigs at the age of 35 days were randomly divided into two groups of 10 animals each, and fed with the same basal diets. The experimental group was supplemented with 25 mg/kg forage of DBH for 180 days, after which the animals were slaughtered and morphometric, histological and immunohistochemical evaluation of their ovaries was performed. In addition, the expression of ovarian growth factors BMP15 and GDF9 in oocytes and cumulus cells was analyzed by RT-PCR. A significant increase in body weight and average daily gain at day 145 in the DBH-supplemented group was established. The length of the ovaries in the treated animals also was enhanced. More pools of primordial follicles, involved in intensive growth, as well as a larger diameter of primary and tertiary follicles were found in the ovaries of DBH-supplemented animals. These findings corresponded with an increase in the expression of GDF9 mRNA in the oocytes and cumulus cells. At the same time, signs of atresia in the Graafian follicles of treated animals were observed. The supplementation with DBH stimulates the early stages of folliculogenesis in gilts, but provokes atresia in the last stage of follicular development.Biološka svojstva pčelinjeg trutovskog legla čine ga idealnim dodatkom za poboljšanje rasta u stočarstvu umjesto zabranjenih hormonskih anabolika i antibiotika. Ipak, utjecaj trutovskog legla na jajnike u sisavaca još uvijek nije dovoljno istražen. U ovom se radu analiziran je utjecaj homogenata trutovskog legla (DBH) u prehrani nazimica na folikulogenezu. Ženke pasmine veliki jorkšir u dobi od 35 dana nasumično su podijeljene u dvije skupine po 10 životinja, s jednakim osnovnim prehrambenim obrokom. Pokusnoj skupini u krmu je dodavano 25 mg/kg DBH-a tijekom 180 dana, nakon čega su životinje usmrćene te je učinjena morfometrijska, histološka i imunohistokemijska procjena jajnika. Zatim je u oocitama i stanicama kumulusa RT-PCR-om analiziran izražaj faktora rasta jajnika, BMP15 i GDF9. U skupini s dodatkom prehrani DBH ustanovljen je znakovit porast tjelesne mase i prosječnog dnevnog prinosa 145. dan. Povećana je i dužina jajnika u pokusnih životinja. U životinja hranjenih dodatkom pronađeno je više nakupina primordijalnih folikula uključenih u intenzivan rast, kao i veći promjer primarnih i tercijarnih folikula. Ovi su rezultati u skladu s porastom izražaja GDF9 mRNA u oocitama i stanicama kumulusa. Istodobno su opaženi znakovi atrezije u Graafovim folikulima pokusnih životinja. Dodatak prehrani DBH stimulira rane stadije folikulogeneze u nazimica, ali uzrokuje atreziju u posljednjem stadiju folikularnog razvoja

Structure- and interaction-based design of anti-SARS-CoV-2 aptamers

Aptamer selection against novel infections is a complicated and time-consuming approach. Synergy can be achieved by using computational methods together with experimental procedures. This study aims to develop a reliable methodology for a rational aptamer in silico et vitro design. The new approach combines multiple steps: (1) Molecular design, based on screening in a DNA aptamer library and directed mutagenesis to fit the protein tertiary structure; (2) 3D molecular modeling of the target; (3) Molecular docking of an aptamer with the protein; (4) Molecular dynamics (MD) simulations of the complexes; (5) Quantum-mechanical (QM) evaluation of the interactions between aptamer and target with further analysis; (6) Experimental verification at each cycle for structure and binding affinity by using small-angle X-ray scattering, cytometry, and fluorescence polarization. By using a new iterative design procedure, structure- and interaction-based drug design (SIBDD), a highly specific aptamer to the receptorbinding domain of the SARS-CoV-2 spike protein, was developed and validated. The SIBDD approach enhances speed of the high-affinity aptamers development from scratch, using a target protein structure. The method could be used to improve existing aptamers for stronger binding. This approach brings to an advanced level the development of novel affinity probes, functional nucleic acids. It offers a blueprint for the straightforward design of targeting molecules for new pathogen agents and emerging variant

Dysfunction in the βII Spectrin-Dependent Cytoskeleton Underlies Human Arrhythmia.

Background: The cardiac cytoskeleton plays key roles in maintaining myocyte structural integrity in health and disease. In fact, human mutations in cardiac cytoskeletal elements are tightly linked with cardiac pathologies including myopathies, aortopathies, and dystrophies. Conversely, the link between cytoskeletal protein dysfunction in cardiac electrical activity is not well understood, and often overlooked in the cardiac arrhythmia field. Methods and Results: Here, we uncover a new mechanism for the regulation of cardiac membrane excitability. We report that βII spectrin, an actin-associated molecule, is essential for the post-translational targeting and localization of critical membrane proteins in heart. βII spectrin recruits ankyrin-B to the cardiac dyad, and a novel human mutation in the ankyrin-B gene disrupts the ankyrin-B/βII spectrin interaction leading to severe human arrhythmia phenotypes. Mice lacking cardiac βII spectrin display lethal arrhythmias, aberrant electrical and calcium handling phenotypes, and abnormal expression/localization of cardiac membrane proteins. Mechanistically, βII spectrin regulates the localization of cytoskeletal and plasma membrane/sarcoplasmic reticulum protein complexes that include the Na/Ca exchanger, RyR2, ankyrin-B, actin, and αII spectrin. Finally, we observe accelerated heart failure phenotypes in βII spectrin-deficient mice. Conclusions: Our findings identify βII spectrin as critical for normal myocyte electrical activity, link this molecule to human disease, and provide new insight into the mechanisms underlying cardiac myocyte biology

Mathematical Modeling of Vegetation Heterogeneity and Complex Topography Effects on Turbulent Exchange of GHG within the Atmospheric Surface Layer

The local-scale 2D and 3D models of greenhouse gases (GHG) exchange between a non-uniform land surface and the atmosphere were developed. They are based on solution of the system of averaged Navier-Stokes, continuity and diffusion-advection equations. For numerical solution of the differential equations the stable finite-difference schemes were suggested. The models were applied to derive effects of complex topography and vegetation heterogeneity on 2D-3D air flow patterns, as well as on CO2 exchange within the atmospheric surface layer. Several numerical experiments were also provided to describe the air-flow re-establishing after its interaction with some obstacle (e.g., forest edge). Quantitative criteria for selection of the experimental sites for continuous eddy covariance flux measurements characterized by minimum effects of horizontal advection on measured fluxes were suggested

Structure and properties of exotic nano- and mesodiamonds with pentagonal symmetry

A comprehensive critical survey of structures of exotic nano-, meso- and microdiamonds with dodecahedral and icosahedral symmetry (N/MDPS) is presented. Due to their high dodecahedral or icosahedral symmetry, the unique complex atomic and electronic structure of N/MDPS leads to transport and mechanical properties very promising for photonic, quantum, and nanomechanical applications. To explain the nature of diamonds, theoretical models have been proposed based on the formation of twinned structures consisting of either 5 or 20 symmetrically equivalent tetrahedral and prismatic fragments of the face-centered cubic lattice with the formation of star-shaped or icosahedral clusters, respectively. It has been shown that these twinned nano- and mesodiamonds have limited dimensions due to accumulation of uncompensated structural stresses arising from the deviation of the angles between diamond facets from perfect 72 degrees in tetrahedral fragments of the face-centered cubic lattice to 70.5 degrees between five symmetrically equivalent twinned fragments