Is MOOC Learning Different for Dropouts? A Visually-Driven, Multi-granularity Explanatory ML Approach

Millions of people have enrolled and enrol (especially in the Covid-19 pandemic world) in MOOCs. However, the retention rate of learners is notoriously low. The majority of the research work on this issue focuses on predicting the dropout rate, but very few use explainable learning patterns as part of this analysis. However, visual representation of learning patterns could provide deeper insights into learners' behaviour across different courses, whilst numerical analyses can -- and arguably, should -- be used to confirm the latter. Thus, this paper proposes and compares different granularity visualisations for learning patterns (based on clickstream data) for both course completers and non-completers. In the large-scale MOOCs we analysed, across various domains, our fine-grained, fish-eye visualisation approach showed that non-completers are more likely to jump forward in their learning sessions, often on a 'catch-up' path, whilst completers exhibit linear behaviour. For coarser, bird-eye granularity visualisation, we observed learners' transition between types of learning activity, obtaining typed transition graphs. The results, backed up by statistical significance analysis and machine learning, provide insights for course instructors to maintain engagement of learners by adapting the course design to not just 'dry' predicted values, but explainable, visually viable paths extracted.Comment: Intelligent Tutoring Systems. ITS 2020. Lecture Notes in Computer Science, vol 1214

Glucoamylase isoform (GAII) purified from a thermophilic fungus Scytalidium thermophilum 15.8 with biotechnological potential

Scytalidium thermophilum 15.8 produced two extracellular glucoamylases. Using a DEAE-Cellulose chromatographic column glucoamylases form II (GAII) was separated and purified from glucoamylases form I (GAI) that was previously purified and characterised (Cereia et al., 2000) when the filtrate of the culture medium was applied to a DEAE-Cellulose chromatographic column. GAII bound to the DEAECellulose and was eluted with a NaCl gradient, while GAI did not bind to the resin. GAII presentedelectrophoretic homogeneity in 6% denaturing and non-denaturing PAGE, separately, with a molecular mass of 83 kDa, after the second round DEAE-Cellulose purification step. The enzyme pI was 7.2.Optima pH and activity temperature were 5.5 and 55ºC respectively for starch and maltose as substrates, with a termostability of 2.5 min at 60ºC. Enzymatic activities were activated by 1 mM Na+, Mn2+ and Mg2+ or 10 mM NH4+, Ba2+ and Mg2+. The carbohydrate content was 10%. The kinetic parameters Km and Vmax with starch and maltose as substrate were 0.2 and 1.5 mg/ml, and 22.3 and 4.39 U/mg of protein, respectively. The amino acid sequence of GAII had 92% homology with theglucoamylase of Humicola grisea var. thermoidea after 13 cycles. Generally, GAII had different properties compared with GAI (Cereia et al., 2000)

Diffusion microscopic MRI of the mouse embryo: Protocol and practical implementation in the splotch mouse model

Advanced methodologies for visualizing novel tissue contrast are essential for phenotyping the ever-increasing number of mutant mouse embryos being generated. Although diffusion microscopic MRI (μMRI) has been used to phenotype embryos, widespread routine use is limited by extended scanning times, and there is no established experimental procedure ensuring optimal data acquisition

Operator theory and function theory in Drury-Arveson space and its quotients

The Drury-Arveson space $H^2_d$, also known as symmetric Fock space or the $d$-shift space, is a Hilbert function space that has a natural $d$-tuple of operators acting on it, which gives it the structure of a Hilbert module. This survey aims to introduce the Drury-Arveson space, to give a panoramic view of the main operator theoretic and function theoretic aspects of this space, and to describe the universal role that it plays in multivariable operator theory and in Pick interpolation theory.Comment: Final version (to appear in Handbook of Operator Theory); 42 page

Survey of Nutrition Management Practices in Centers for Pediatric Intestinal Rehabilitation

Background: Nutrition management of pediatric intestinal failure (IF) requires interdisciplinary coordination of parenteral nutrition (PN) and enteral nutrition (EN) support. Nutrition strategies used by specialists in pediatric intestinal rehabilitation to promote gut adaptation and manage complications have not been previously summarized. Methods: A practice survey was distributed to members of the dietitian subgroup of the American Society for Parenteral and Enteral Nutrition Pediatric Intestinal Failure Section. The survey included 24 open‐ended questions related to PN and enteral feeding strategies, nutrition management of PN‐associated liver disease, and laboratory monitoring. Results: Dietitians from 14 centers completed the survey. Management components for patients at risk for cholestasis were consistent and included fat minimization, trace element modification, avoiding PN overfeeding, and providing EN. Parenteral amino acid solutions designed for infants/young children are used in patients <1 or 2 years of age. Trace minerals are dosed individually in 10 of 14 centers. Eleven centers prescribe a continuous infusion of breast milk or elemental formula 1–2 weeks after resection while 3 centers determine the formula type by the extent of resection. Most (86%) centers do not have a protocol for initiating oral/motor therapy. Laboratory panel composition varied widely by center. The selection and frequency of use depended on clinical variables, including cholestatic status, exclusive vs partial PN dependence, postrepletion verification vs routine monitoring, intestinal anatomy, and acuity of care. Conclusion: EN and PN management strategies are relatively consistent among U.S. centers. Collaborative initiatives are necessary to define better practices and establish laboratory monitoring guidelines.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/145220/1/ncp10040_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145220/2/ncp10040.pd

Iron, silicate, and light co-limitation of three Southern Ocean diatom species

The effect of combined iron, silicate, and light co-limitation was investigated in the three diatom species Actinocyclus sp. Ehrenberg, Chaetoceros dichaeta Ehrenberg, and Chaetoceros debilis Cleve, isolated from the Southern Ocean (SO). Growth of all species was co-limited by iron and silicate, reflected in a significant increase in the number of cell divisions compared to the control. Lowest relative Si uptake and drastic frustule malformation was found under iron and silicate co-limitation in C. dichaeta, while Si limitation in general caused cell elongation in both Chaetoceros species. Higher light intensities similar to SO surface conditions showed a negative impact on growth of C. dichaeta and Actinocyclus sp. and no effect on C. debilis. This is in contrast to the assumed light limitation of SO diatoms due to deep wind driven mixing. Our results suggest that growth and species composition of Southern Ocean diatoms is influenced by a sensitive interaction of the abiotic factors, iron, silicate, and light

IL-6 and IL-27 play both distinct and redundant roles in regulating CD4 T-cell responses during chronic viral infection

The IL-6 cytokine family signals through the common signal transduction molecule gp130 combined with a cytokine-specific receptor. Gp130 signaling on CD4 T cells is vital in controlling chronic infection of mice with lymphocytic choriomeningitis virus clone 13 (LCMV Cl13), but the precise role of individual members of the IL-6 cytokine family is not fully understood. Transcriptional analysis highlighted the importance of gp130 signaling in promoting key processes in CD4 T cells after LCMV Cl13 infection, particularly genes associated with T follicular helper (Tfh) cell differentiation and IL-21 production. Further, Il27r−/−Il6ra−/− mice failed to generate antibody or CD8 T-cell immunity and to control LCMV Cl13. Transcriptomics and phenotypic analyses of Il27r−/−Il6ra−/− Tfh cells revealed that IL-6R and IL-27R signaling was required to activate key pathways within CD4 T cells. IL-6 and IL-27 signaling has distinct and overlapping roles, with IL-6 regulating Tfh differentiation, IL-27 regulating CD4 T cell survival, and both redundantly promoting IL-21

Capture the fracture: a best practice framework and global campaign to break the fragility fracture cycle

Summary The International Osteoporosis Foundation (IOF) Capture the Fracture Campaign aims to support implementation of Fracture Liaison Services (FLS) throughout the world. Introduction FLS have been shown to close the ubiquitous secondary fracture prevention care gap, ensuring that fragility fracture sufferers receive appropriate assessment and intervention to reduce future fracture risk. Methods Capture the Fracture has developed internationally endorsed standards for best practice, will facilitate change at the national level to drive adoption of FLS and increase awareness of the challenges and opportunities presented by secondary fracture prevention to key stakeholders. The Best Practice Framework (BPF) sets an international benchmark for FLS, which defines essential and aspirational elements of service delivery. Results The BPF has been reviewed by leading experts from many countries and subject to beta-testing to ensure that it is internationally relevant and fit-for-purpose. The BPF will also serve as a measurement tool for IOF to award ‘Capture the Fracture Best Practice Recognition’ to celebrate successful FLS worldwide and drive service development in areas of unmet need. The Capture the Fracture website will provide a suite of resources related to FLS and secondary fracture prevention, which will be updated as new materials become available. A mentoring programme will enable those in the early stages of development of FLS to learn from colleagues elsewhere that have achieved Best Practice Recognition. A grant programme is in development to aid clinical systems which require financial assistance to establish FLS in their localities. Conclusion Nearly half a billion people will reach retirement age during the next 20 years. IOF has developed Capture the Fracture because this is the single most important thing that can be done to directly improve patient care, of both women and men, and reduce the spiralling fracture-related care costs worldwide.</p

The regulatory subunit of PKA-I remains partially structured and undergoes β-aggregation upon thermal denaturation

Background: The regulatory subunit (R) of cAMP-dependent protein kinase (PKA) is a modular flexible protein that responds with large conformational changes to the binding of the effector cAMP. Considering its highly dynamic nature, the protein is rather stable. We studied the thermal denaturation of full-length RIα and a truncated RIα(92-381) that contains the tandem cyclic nucleotide binding (CNB) domains A and B. Methodology/Principal Findings: As revealed by circular dichroism (CD) and differential scanning calorimetry, both RIα proteins contain significant residual structure in the heat-denatured state. As evidenced by CD, the predominantly α-helical spectrum at 25°C with double negative peaks at 209 and 222 nm changes to a spectrum with a single negative peak at 212-216 nm, characteristic of β-structure. A similar α→β transition occurs at higher temperature in the presence of cAMP. Thioflavin T fluorescence and atomic force microscopy studies support the notion that the structural transition is associated with cross-β-intermolecular aggregation and formation of non-fibrillar oligomers. Conclusions/Significance: Thermal denaturation of RIα leads to partial loss of native packing with exposure of aggregation-prone motifs, such as the B' helices in the phosphate-binding cassettes of both CNB domains. The topology of the β-sandwiches in these domains favors inter-molecular β-aggregation, which is suppressed in the ligand-bound states of RIα under physiological conditions. Moreover, our results reveal that the CNB domains persist as structural cores through heat-denaturation. © 2011 Dao et al