297 research outputs found
Confidence assessment in the teaching of basic science
A scheme is described for including information about confidence in the computerâbased assessment of students. After each answer, students declare a confidence level of 1, 2, or 3. If the answer is correct, then this is the mark awarded. If not, marks of 0, â2, or â6 are awarded Students do well on this scheme if they can discriminate between when they are sure of correct answers and when they are partly guessing. In selfâassessment, students are trained to reflect on their reasoning, and to develop the skills of correct confidence judgement. The task of writing tests is simplified, since it becomes less important to ask complex questions. Simple direct questions discriminate better between students than they do with ordinary marking. Good students answer correctly with high confidence, while weak students moderate their confidence level if they know they are uncertain, or else lose heavily when they make mistakes. Preliminary data are presented from selfâassessment trials amongst medical students
Localist representation can improve efficiency for detection and counting
Almost all representations have both distributed and localist aspects, depending upon what properties of the data are being considered. With noisy data, features represented in a localist way can be detected very efficiently, and in binary representations they can be counted more efficiently than those represented in a distributed way. Brains operate in noisy environments, so the localist representation of behaviourally important events is advantageous, and fits what has been found experimentally. Distributed representations require more neurons to perform as efficiently, but they do have greater versatility
Association of the CCR5 gene with juvenile idiopathic arthritis
The CC chemokine receptor 5 (CCR5) has been shown to be important in the recruitment of T-helper cells to the synovium, where they accumulate, drive the inflammatory process and the consequent synovitis and joint destruction. A 32 base-pair insertion/deletion variant (CCR5Î32) within the gene leads to a frame shift and a nonfunctional receptor. CCR5Î32 has been investigated for its association with juvenile idiopathic arthritis (JIA), with conflicting results. The aim of this study was to investigate whether CCR5Î32 is associated with JIA in an UK population. CCR5Î32 was genotyped in JIA cases (n=1054) and healthy controls (n=3129) and genotype and allele frequencies were compared. A meta-analysis of our study combined with previously published studies was performed. CCR5Î32 was significantly associated with protection from developing JIA, in this UK data set (P(trend)=0.006, odds ratio (OR) 0.79 95% confidence interval (95% CI): 0.66-0.94). The meta-analysis of all published case-control association studies confirmed the protective association with JIA (P=0.001 OR 0.82 95% CI: 0.73-0.93). CCR5Î32 is a functional variant determining the number of receptors on the surface of T cells, and it is hypothesized that the level of CCR5 expression could influence the migration of proinflammatory T cells into the synovium and thus susceptibility to JIA
Association of the AFF3 gene and IL2/IL21 gene region with juvenile idiopathic arthritis
Recent genetic studies have led to identification of numerous loci that are associated with susceptibility to autoimmune diseases. The strategy of using information from these studies has facilitated the identification of novel juvenile idiopathic arthritis (JIA) susceptibility loci, specifically, PTPN22 and IL2RA. Several novel autoimmune susceptibility loci have recently been identified, and we hypothesise that single-nucleotide polymorphisms (SNPs) within these genes may also be JIA susceptibility loci. Five SNPs within the genes AFF3, IL2/IL21, IL7R, CTLA4 and CD226, previously associated with multiple autoimmune diseases were genotyped, in a large data set of Caucasian JIA patients and controls, and tested for association with JIA. We identified two susceptibility loci for JIA, AFF3 and the IL2/IL21 region and additional weak evidence supporting an association with the CTLA4 and IL7R genes, which warrant further investigation. All results require validation in independent JIA data sets. Further characterisation of the specific causal variants will be required before functional studies can be performed
Association of the AFF3 gene and IL2/IL21 gene region with juvenile idiopathic arthritis
Recent genetic studies have led to identification of numerous loci that are associated with susceptibility to autoimmune diseases. The strategy of using information from these studies has facilitated the identification of novel juvenile idiopathic arthritis (JIA) susceptibility loci, specifically, PTPN22 and IL2RA. Several novel autoimmune susceptibility loci have recently been identified, and we hypothesise that single-nucleotide polymorphisms (SNPs) within these genes may also be JIA susceptibility loci. Five SNPs within the genes AFF3, IL2/IL21, IL7R, CTLA4 and CD226, previously associated with multiple autoimmune diseases were genotyped, in a large data set of Caucasian JIA patients and controls, and tested for association with JIA. We identified two susceptibility loci for JIA, AFF3 and the IL2/IL21 region and additional weak evidence supporting an association with the CTLA4 and IL7R genes, which warrant further investigation. All results require validation in independent JIA data sets. Further characterisation of the specific causal variants will be required before functional studies can be performed
Confidence and competence with mathematical procedures
Confidence assessment (CA), in which students state alongside each of their answers a confidence level expressing how certain they are, has been employed successfully within higher education. However, it has not been widely explored with school pupils. This study examined how school mathematics pupils (N = 345) in five different secondary schools in England responded to the use of a CA instrument designed to incentivise the eliciting of truthful confidence ratings in the topic of directed (positive and negative) numbers. Pupils readily understood the negative marking aspect of the CA process and their facility correlated with their mean confidence with r = .546, N = 336, p < .001, indicating that pupils were generally well calibrated. Pupilsâ comments indicated that the vast majority were positive about the CA approach, despite its dramatic differences from more usual assessment practices in UK schools. Some pupils felt that CA promoted deeper thinking, increased their confidence and had a potential role to play in classroom formative assessment
Failure of feedback as a putative common mechanism of spreading depolarizations in migraine and stroke
The stability of cortical function depends critically on proper regulation.
Under conditions of migraine and stroke a breakdown of transmembrane chemical
gradients can spread through cortical tissue. A concomitant component of this
emergent spatio-temporal pattern is a depolarization of cells detected as slow
voltage variations. The velocity of ~3 mm/min indicates a contribution of
diffusion. We propose a mechanism for spreading depolarizations (SD) that rests
upon a nonlocal or non-instantaneous feedback in a reaction-diffusion system.
Depending upon the characteristic space and time scales of the feedback, the
propagation of cortical SD can be suppressed by shifting the bifurcation line,
which separates the parameter regime of pulse propagation from the regime where
a local disturbance dies out. The optimisation of this feedback is elaborated
for different control schemes and ranges of control parameters
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