The effect of functional roles on perceived group efficiency during computer-supported collaborative learning

In this article, the effect of functional roles on group performance and collaboration during computer-supported collaborative learning (CSCL) is investigated. Especially the need for triangulating multiple methods is emphasised: Likert-scale evaluation questions, quantitative content analysis of e-mail communication and qualitative analysis of open-ended questions were used. A comparison of fourty-one questionnaire observations, distributed over thirteen groups in two research conditions – groups with prescribed functional roles (n = 7, N = 18) and nonrole groups (n = 6, N = 23) – revealed no main effect for performance (grade). Principal axis factoring of the Likert-scales revealed a latent variable that was interpreted as perceived group efficiency (PGE). Multilevel modelling (MLM) yielded a positive marginal effect of PGE. Most groups in the role condition report a higher degree of PGE than nonrole groups. Content analysis of e-mail communication of all groups in both conditions (role n = 7, N = 25; nonrole n = 6, N = 26) revealed that students in role groups contribute more ‘coordination’ focussed statements. Finally, results from cross case matrices of student responses to open-ended questions support the observed marginal effect that most role groups report a higher degree of perceived group efficiency than nonrole groups

Prion-like α-synuclein pathology in the brain of infants with Krabbe disease

Krabbe disease is an infantile neurodegenerative disorder resulting from pathogenic variants in the GALC gene that causes accumulation of the toxic sphingolipid psychosine. GALC variants are also associated with Lewy body diseases, an umbrella term for age-associated neurodegenerative diseases in which the protein α-synuclein aggregates into Lewy bodies. To explore whether α-synuclein in Krabbe disease has pathological similarities to that in Lewy body disease, we performed an observational post-mortem study of Krabbe disease brain tissue (n = 4) compared to infant controls (n = 4) and identified widespread accumulations of α-synuclein. To determine whether α-synuclein in Krabbe disease brain displayed disease-associated pathogenic properties we evaluated its seeding capacity using the real-time quaking-induced conversion assay in two cases for which frozen tissue was available and strikingly identified aggregation into fibrils similar to those observed in Lewy body disease, confirming the prion-like capacity of Krabbe disease-derived α-synuclein. These observations constitute the first report of prion-like α-synuclein in the brain tissue of infants and challenge the putative view that α-synuclein pathology is merely an age-associated phenomenon, instead suggesting it results from alterations to biological pathways, such as sphingolipid metabolism. Our findings have important implications for understanding the mechanisms underlying Lewy body formation in Lewy body disease

Compositional controls on oceanic plates : geophysical evidence from the MELT area

Author Posting. © The Authors, 2005. This is the author's version of the work. It is posted here by permission of Nature Publishing Group for personal use, not for redistribution. The definitive version was published in Nature 437 (2005): 249-252, doi:10.1038/nature04014.Magnetotelluric (MT) and seismic data, collected during the MELT experiment at the Southern East Pacific Rise (SEPR) constrain the distribution of melt beneath this mid-ocean-ridge spreading center and also the evolution of the oceanic lithosphere during its early cooling history. In this paper, we focus on structure imaged at distances ~100 to 350 km east of the ridge crest, corresponding to seafloor ages of ~1.3 to 4.5 Ma, where the seismic and electrical conductivity structure is nearly constant, independent of age. Beginning at a depth of about 60 km, there is a large increase in electrical conductivity and a change from isotropic to transversely anisotropic electrical structure with higher conductivity in the direction of fast propagation for seismic waves. Because conductive cooling models predict structure that increases in depth with age, extending to about 30 km at 4.5 Ma, we infer that the structure of young oceanic plates is instead controlled by a decrease in water content above 60 km induced by the melting process beneath the spreading center.US participation in the MELT experiment and subsequent analysis was funded by NSF grants through the Marine Geology and Geophysics Program, Ocean Sciences Division

Evolution of brain MRI lesions in paediatric myelin-oligodendrocyte glycoprotein antibody-associated disease (MOGAD) and its relevance to disease course

BACKGROUND: Lesion resolution is often observed in children with myelin-oligodendrocyte glycoprotein antibody-associated disease (MOGAD), and asymptomatic lesions are less commonly reported in MOGAD than in multiple sclerosis (MS). OBJECTIVE: We aimed to evaluate brain MRI changes over time in paediatric MOGAD. METHODS: Retrospective study in eight UK paediatric neuroscience centres. Acute brain MRI and available follow-up MRIs were reviewed. Predictors for lesion dynamic were evaluated using multivariable regression and Kaplan-Meier survival analyses were used to predict risk of relapse, disability and MOG-Ab status. RESULTS: 200 children were included (MOGAD 97; MS 103). At first MRI post attack, new symptomatic and asymptomatic lesions were seen more often in MS versus MOGAD (52/103 vs 28/97; p=0.002 and 37/103 vs 11/97; p<0.001); 83% of patients with MOGAD showed at least one lesion's resolution at first follow-up scan, and 23% had normal MRI. Only 1 patient with MS had single lesion resolution; none had normal MRI. Disappearing lesions in MOGAD were seen in 40% after the second attack, 21% after third attack and none after the fourth attack.New lesions at first follow-up scan were associated with increased likelihood of relapse (p=0.02) and persistent MOG-Ab serostatus (p=0.0016) compared with those with no new lesions. Plasma exchange was associated with increased likelihood of lesion resolution (p=0.01). Longer time from symptom onset to steroids was associated with increased likelihood of new lesions; 50% increase at 20 days (p=0.01). CONCLUSIONS: These striking differences in lesion dynamics between MOGAD and MS suggest greater potential to repair. Early treatment with steroids and plasma exchange is associated with reduced likelihood of new lesions

Evolution of brain MRI lesions in paediatric myelin-oligodendrocyte glycoprotein antibody-associated disease (MOGAD) and its relevance to disease course

Background: Lesion resolution is often observed in children with myelin-oligodendrocyte glycoprotein antibody-associated disease (MOGAD), and asymptomatic lesions are less commonly reported in MOGAD than in multiple sclerosis (MS). Objective: We aimed to evaluate brain MRI changes over time in paediatric MOGAD. Methods: Retrospective study in eight UK paediatric neuroscience centres. Acute brain MRI and available follow-up MRIs were reviewed. Predictors for lesion dynamic were evaluated using multivariable regression and Kaplan-Meier survival analyses were used to predict risk of relapse, disability and MOG-Ab status. Results:200 children were included (MOGAD 97; MS 103). At first MRI post-attack, new symptomatic and asymptomatic lesions were seen more often in MS vs MOGAD (52/103 vs 28/97; p=0.002 and 37/103 vs 11/97; p<0.001); 83% of MOGAD patients showed at least one lesion’s resolution at 1st follow‐up scan, and 23% had normal MRI. Only 1 MS patient had single lesion resolution; none had normal MRI. Disappearing lesions in MOGAD were seen in 40% after the 2nd attack, 21% after 3rd attack and none after the 4th attack. New lesions at 1st follow-up scan were associated with increased likelihood of relapse (p=0.02) and persistent MOG-Ab serostatus (p=0.0016) compared to those with no new lesions. Plasma exchange was associated with increased likelihood of lesion resolution (p=0.01). Longer time from symptom onset to steroids was associated with increased likelihood of new lesions; 50% increase at 20 days (p=0.01). Conclusions and Relevance: These striking differences in lesion dynamics between MOGAD and MS suggest greater potential to repair. Early treatment with steroids and plasma exchange is associated with reduced likelihood of new lesions

Glucose transporter-1 deficiency syndrome: the expanding clinical and genetic spectrum of a treatable disorder

Glucose transporter-1 deficiency syndrome is caused by mutations in the SLC2A1 gene in the majority of patients and results in impaired glucose transport into the brain. From 2004-2008, 132 requests for mutational analysis of the SLC2A1 gene were studied by automated Sanger sequencing and multiplex ligation-dependent probe amplification. Mutations in the SLC2A1 gene were detected in 54 patients (41%) and subsequently in three clinically affected family members. In these 57 patients we identified 49 different mutations, including six multiple exon deletions, six known mutations and 37 novel mutations (13 missense, five nonsense, 13 frame shift, four splice site and two translation initiation mutations). Clinical data were retrospectively collected from referring physicians by means of a questionnaire. Three different phenotypes were recognized: (i) the classical phenotype (84%), subdivided into early-onset (<2 years) (65%) and late-onset (18%); (ii) a non-classical phenotype, with mental retardation and movement disorder, without epilepsy (15%); and (iii) one adult case of glucose transporter-1 deficiency syndrome with minimal symptoms. Recognizing glucose transporter-1 deficiency syndrome is important, since a ketogenic diet was effective in most of the patients with epilepsy (86%) and also reduced movement disorders in 48% of the patients with a classical phenotype and 71% of the patients with a non-classical phenotype. The average delay in diagnosing classical glucose transporter-1 deficiency syndrome was 6.6 years (range 1 month-16 years). Cerebrospinal fluid glucose was below 2.5 mmol/l (range 0.9-2.4 mmol/l) in all patients and cerebrospinal fluid : blood glucose ratio was below 0.50 in all but one patient (range 0.19-0.52). Cerebrospinal fluid lactate was low to normal in all patients. Our relatively large series of 57 patients with glucose transporter-1 deficiency syndrome allowed us to identify correlations between genotype, phenotype and biochemical data. Type of mutation was related to the severity of mental retardation and the presence of complex movement disorders. Cerebrospinal fluid : blood glucose ratio was related to type of mutation and phenotype. In conclusion, a substantial number of the patients with glucose transporter-1 deficiency syndrome do not have epilepsy. Our study demonstrates that a lumbar puncture provides the diagnostic clue to glucose transporter-1 deficiency syndrome and can thereby dramatically reduce diagnostic delay to allow early start of the ketogenic die

COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study

Background: The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms. Methods: International, prospective observational study of 60 109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms. Results: ‘Typical’ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (≤ 18 years: 69, 48, 23; 85%), older adults (≥ 70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each P &lt; 0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country. Interpretation: This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men