214 research outputs found

    AN INVESTIGATION INTO THE UTILISATION OF SOCIAL MEDIA TO FOSTER TEAM COLLABORATION IN A HIGHER EDUCATION INSTITUTION

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    The COVID-19 pandemic introduced new challenges with subsequent opportunities to teach innovative ways of team collaboration. One example is the utilisation of social media to foster online team collaboration. This study investigates the use of Discord by students, a social media platform originally developed for online gamers, to collaborate virtually to complete project team tasks. The research question – what role a social media tool, namely Discord, plays in fostering team collaboration – was investigated using a qualitative, interpretative approach. Topic modeling identified ten themes, with the most vital theme indicating that students initially used Discord due to the academic requirement but later extensively used the platform because of its convenience and usefulness. Most students continued to use Discord even after completing their studies. While the main reason for adopting the tool was convenience due to peers using the platform, it became a logical and practical platform to communicate with friends, work on completing tasks together, and as a result, create a strong sense of belonging

    Breeding young as a survival strategy during earth’s greatest mass extinction

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    Studies of the effects of mass extinctions on ancient ecosystems have focused on changes in taxic diversity, morphological disparity, abundance, behaviour and resource availability as key determinants of group survival. Crucially, the contribution of life history traits to survival during terrestrial mass extinctions has not been investigated, despite the critical role of such traits for population viability. We use bone microstructure and body size data to investigate the palaeoecological implications of changes in life history strategies in the therapsid forerunners of mammals before and after the Permo-Triassic Mass Extinction (PTME), the most catastrophic crisis in Phanerozoic history. Our results are consistent with truncated development, shortened life expectancies, elevated mortality rates and higher extinction risks amongst post-extinction species. Various simulations of ecological dynamics indicate that an earlier onset of reproduction leading to shortened generation times could explain the persistence of therapsids in the unpredictable, resource-limited Early Triassic environments, and help explain observed body size distributions of some disaster taxa (e.g., Lystrosaurus). Our study accounts for differential survival in mammal ancestors after the PTME and provides a methodological framework for quantifying survival strategies in other vertebrates during major biotic crises

    The malarial exported PFA0660w is an Hsp40 co-chaperone of PfHsp70-x

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    Plasmodium falciparum, the human pathogen responsible for the most dangerous malaria infection, survives and develops in mature erythrocytes through the export of proteins needed for remodelling of the host cell. Molecular chaperones of the heat shock protein (Hsp) family are prominent members of the exportome, including a number of Hsp40s and a Hsp70. PFA0660w, a type II Hsp40, has been shown to be exported and possibly form a complex with PfHsp70-x in the infected erythrocyte cytosol. However, the chaperone properties of PFA0660w and its interaction with human and parasite Hsp70s are yet to be investigated. Recombinant PFA0660w was found to exist as a monomer in solution, and was able to significantly stimulate the ATPase activity of PfHsp70-x but not that of a second plasmodial Hsp70 (PfHsp70-1) or a human Hsp70 (HSPA1A), indicating a potential specific functional partnership with PfHsp70-x. Protein binding studies in the presence and absence of ATP suggested that the interaction of PFA0660w with PfHsp70-x most likely represented a co-chaperone/chaperone interaction. Also, PFA0660w alone produced a concentrationdependent suppression of rhodanese aggregation, demonstrating its chaperone properties. Overall, we have provided the first biochemical evidence for the possible role of PFA0660w as a chaperone and as co-chaperone of PfHsp70-x. We propose that these chaperones boost the chaperone power of the infected erythrocyte, enabling successful protein trafficking and folding, and thereby making a fundamental contribution to the pathology of malaria

    Reliability, construct validity and measurement potential of the ICF comprehensive core set for osteoarthritis

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    <p>Abstract</p> <p>Background</p> <p>This study aimed to investigate the reliability and construct validity of the International Classification of Functioning, Disability and Health (ICF) Comprehensive Core Set for osteoarthritis (OA) in order to test its possible use as a measuring tool for functioning.</p> <p>Methods</p> <p>100 patients with OA (84 F, 16 M; mean age 63 yr) completed forms including demographic and clinical information besides the Short Form (36) Health Survey (SF-36<sup>®</sup>) and the Western Ontario and McMaster Universities Index of Osteoarthritis (WOMAC). The ICF Comprehensive Core Set for OA was filled by health professionals. The internal construct validities of "Body Functions-Body structures" (BF-BS), "Activity" (A), "Participation" (P) and "Environmental Factors" (EF) domains were tested by Rasch analysis and reliability by internal consistency and person separation index (PSI). External construct validity was evaluated by correlating the Rasch transformed scores with SF-36 and WOMAC.</p> <p>Results</p> <p>In each scale, some items showing disordered thresholds were rescored, testlets were created to overcome the problem of local dependency and items that did not fit to the Rasch model were deleted. The internal construct validity of the four scales (BF-BS 16 items, A 8 items, P 7 items, EF 13 items) were good [mean item fit (SD) 0.138 (0.921), 0.216 (1.237), 0.759 (0.986) and -0.079 (2.200); person item fit (SD) -0.147 (0.652), -0.241 (0.894), -0.310 (1.187) and -0.491 (1.173) respectively], indicating a single underlying construct for each scale. The scales were free of differential item functioning (DIF) for age, gender, years of education and duration of disease. Reliabilities of the BF-BS, A, P, and EF scales were good with Cronbach's alphas of 0.79, 0.86, 0.88, and 0.83 and PSI's of 0.76, 0.86, 0.87, and 0.71, respectively. Rasch scores of BF-BS, A, and P showed moderate correlations with SF-36 and WOMAC scores where the EF had significant but weak correlations only with SF36-Social Functioning and SF36-Mental Health.</p> <p>Conclusion</p> <p>Since the four different scales derived from BF-BS, A, P, and EF components of the ICF core set for OA were shown to be valid and reliable through a combination of Rasch analysis and classical psychometric methods, these might be used as clinical assessment tools.</p

    Serial counts of Mycobacterium tuberculosis in sputum as surrogate markers of the sterilising activity of rifampicin and pyrazinamide in treating pulmonary tuberculosis

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    BACKGROUND: Since the sterilising activity of new antituberculosis drugs is difficult to assess by conventional phase III studies, surrogate methods related to eventual relapse rates are required. METHODS: A suitable method is suggested by a retrospective analysis of viable counts of Mycobacterium tuberculosis in 12-hr sputum collections from 122 newly diagnosed patients with pulmonary tuberculosis in Nairobi, done pretreatment and at 2, 7, 14 and 28 days. Treatment was with isoniazid and streptomycin, supplemented with either thiacetazone (SHT) or rifampicin + pyrazinamide (SHRZ). RESULTS: During days 0–2, a large kill due to isoniazid occurred, unrelated to treatment or HIV status; thereafter it decreased exponentially. SHRZ appeared to have greater sterilising activity than SHT during days 2–7 (p = 0.044), due to rifampicin, and during days 14–28, probably due mainly to pyrazinamide. The greatest discrimination between SHRZ and SHT treatments was found between regression estimates of kill over days 2–28 (p = 0.0005) in patients who remained positive up to 28 days with homogeneous kill rates. No associations were found between regression estimates and the age, sex, and extent of disease or cavitation. An increased kill in HIV seropositive patients, unrelated to the treatment effect, was evident during days 2–28 (p = 0.007), mainly during days 2–7. CONCLUSIONS: Surrogate marker studies should either be in small groups treated with monotherapy during days 2 to about 7 or as add-ons or replacements in isoniazid-containing standard regimens from days 2 to 28 in large groups

    Cranial Ontogeny in Stegoceras validum (Dinosauria: Pachycephalosauria): A Quantitative Model of Pachycephalosaur Dome Growth and Variation

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    Historically, studies of pachycephalosaurs have recognized plesiomorphically flat-headed taxa and apomorphically domed taxa. More recently, it has been suggested that the expression of the frontoparietal dome is ontogenetic and derived from a flat-headed juvenile morphology. However, strong evidence to support this hypothesis has been lacking. Here we test this hypothesis in a large, stratigraphically constrained sample of specimens assigned to Stegoceras validum, the best known pachycephalosaur, using multiple independent lines of evidence including conserved morphology of ornamentation, landmark-based allometric analyses of frontoparietal shape, and cranial bone histology. New specimens show that the diagnostic ornamentation of the parietosquamosal bar is conserved throughout the size range of the sample, which links flat-headed specimens to domed S. validum. High-resolution CT scans of three frontoparietals reveal that vascularity decreases with size and document a pattern that is consistent with previously proposed histological changes during growth. Furthermore, aspects of dome shape and size are strongly correlated and indicative of ontogenetic growth. These results are complementary and strongly support the hypothesis that the sample represents a growth series of a single taxon. Cranial dome growth is positively allometric, proceeds from a flat-headed to a domed state, and confirms the synonymy of Ornatotholus browni as a juvenile Stegoceras. This dataset serves as the first detailed model of growth and variation in a pachycephalosaur. Flat-headed juveniles possess three characters (externally open cranial sutures, tuberculate dorsal surface texture, and open supratemporal fenestrae) that are reduced or eliminated during ontogeny. These characters also occur in putative flat-headed taxa, suggesting that they may also represent juveniles of domed taxa. However, open cranial sutures and supratemporal fenestrae are plesiomorphic within Ornithischia, and thus should be expected in the adult stage of a primitive pachycephalosaur. Additional lines of evidence will be needed to resolve the taxonomic validity of flat-headed pachycephalosaur taxa

    Recombination in West Nile Virus: minimal contribution to genomic diversity

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    Recombination is known to play a role in the ability of various viruses to acquire sequence diversity. We consequently examined all available West Nile virus (WNV) whole genome sequences both phylogenetically and with a variety of computational recombination detection algorithms. We found that the number of distinct lineages present on a phylogenetic tree reconstruction to be identical to the 6 previously reported. Statistically-significant evidence for recombination was only observed in one whole genome sequence. This recombination event was within the NS5 polymerase coding region. All three viruses contributing to the recombination event were originally isolated in Africa at various times, with the major parent (SPU116_89_B), minor parent (KN3829), and recombinant sequence (AnMg798) belonging to WNV taxonomic lineages 2, 1a, and 2 respectively. This one isolated recombinant genome was out of a total of 154 sequences analyzed. It therefore does not seem likely that recombination contributes in any significant manner to the overall sequence variation within the WNV genome

    Automatic radiographic quantification of hand osteoarthritis; accuracy and sensitivity to change in joint space width in a phantom and cadaver study

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    This is the final version of the article. Available from Springer Verlag via the DOI in this record.OBJECTIVE: To validate a newly developed quantification method that automatically detects and quantifies the joint space width (JSW) in hand radiographs. Repeatability, accuracy and sensitivity to changes in JSW were determined. The influence of joint location and joint shape on the measurements was tested. METHODS: A mechanical micrometer set-up was developed to define and adjust the true JSW in an acrylic phantom joint and in human cadaver-derived phalangeal joints. Radiographic measurements of the JSW were compared to the true JSW. Repeatability, systematic error (accuracy) and sensitivity (defined as the smallest detectable difference (SDD)) were determined. The influence of joint position on the JSW measurement was assessed by varying the location of the acrylic phantom on the X-ray detector with respect to the X-ray beam and the influence of joint shape was determined by using morphologically different human cadaver joints. RESULTS: The mean systematic error was 0.052 mm in the phantom joint and 0.210 mm in the cadaver experiment. In the phantom experiments, the repeatability was high (SDD = 0.028 mm), but differed slightly between joint locations (p = 0.046), and a change in JSW of 0.037 mm could be detected. Dependent of the joint shape in the cadaver hand, a change in JSW between 0.018 and 0.047 mm could be detected. CONCLUSIONS: The automatic quantification method is sensitive to small changes in JSW. Considering the published data of JSW decline in the normal and osteoarthritic population, the first signs of OA progression with this method can be detected within 1 or 2 years.This work was funded by the Dutch Arthritis Association (Reumafonds). The study sponsor had no involvement in study design, data collection, data analysis, or interpretation of the results
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