Knockout mice: Is it just genetics? Effect of enriched housing on fibulin-4+/- mice

Background. Fibulin-4 is an extracellular matrix protein expressed by vascular smooth muscle cells that is essential for maintaining arterial integrity. Fibulin-4-/- mice die just before birth due to arterial hemorrhage, but fibulin-4+/- mice appear to be outwardly normal. Experiments were therefore performed to determine whether fibulin-4+/- mice display arterial pathologies on a microscopic scale. After preliminary experiments were performed, a second purpose developed, which was to test the hypothesis that any observed pathologies would be ameliorated by housing the animals in enriched cages. Methodology. Fibulin-4+/- and wild-type mice were housed either four/cage in standard cages or two per cage in larger cages, each cage containing a tunnel and a wheel. After three weeks the mice were sacrificed, and the aortas perfusion-fixed and excised for light and electron microscopy. Principle Findings. When the mice were in standard cages, localized regions of disorganized extracellular matrix and collagen fibers consistently appeared between some of the medial smooth muscle cells in the fibulin-4+/- mice. In the wild-type mice, the smooth muscle cells were closely connected to each other and the media was more compact. The number of disorganized regions per square mm was significantly greater for fibulin-4+/- mice (172±43 (SEM)) than for wild-type mice (15±8) (p<0.01, n = 8). When the mice were in enriched cages, the fibulin-4+/- mice showed significantly fewer disorganized regions than those in standard cages (35±12) (p<0.05, n = 8). The wild type mice also showed fewer disorganized regions (3±2), but this difference was not significant. Conclusions. These results indicate that arterial pathologies manifested in fibulin-4+/- mice can be reduced by enriching the housing conditions, and imply that appropriate environments may counteract the effects of some genetic deficiencies

Individual differences in eyewitness accuracy across multiple lineups of faces

Theories of face recognition in cognitive psychology stipulate that the hallmark of accurate identification is the ability to recognize a person consistently, across different encounters. In this study, we apply this reasoning to eyewitness identification by assessing the recognition of the same target person repeatedly, over six successive lineups. Such repeat identifications are challenging and can be performed only by a proportion of individuals, both when a target exhibits limited and more substantial variability in appearance across lineups (Experiments 1 and 2). The ability to do so correlates with individual differences in identification accuracy on two established tests of unfamiliar face recognition (Experiment 3). This indicates that most observers have limited facial representations of target persons in eyewitness scenarios, which do not allow for robust identification in most individuals, partly due to limitations in their ability to recognize unfamiliar faces. In turn, these findings suggest that consistency of responses across multiple lineups of faces could be applied to assess which individuals are accurate eyewitnesses

Optimisation of self-supporting towers for small wind turbines

Small wind turbines have the potential to provide a significant amount of useful electricity; particularly in urban areas where it is necessary to use self-supporting monopole towers. Their take-up can be increased by reducing tower costs. The numerical optimisation technique called differential evolution (DE) was used to design a minimal mass self-supporting tower for a 5 kW wind turbine, whilst retaining the required strength and stability. The main problem in the optimisation was the limited availability of appropriate simple equations for buckling analysis of the chosen octagonal geometry as required for design certification to the appropriate international standards. Performing linear buckling analysis (which is unsuitable for global optimisation) on towers designed to meet the available buckling equations showed that the buckling strength was significantly overestimated for low wall thicknesses. A correction factor was formulated and applied to the existing buckling equations to remove this inconsistency. DE was then used to design a tower that was 7% lighter and 20% more resistant to buckling than the current reference design

Reliability and validity of student peer assessment in medical education: a systematic review

Background: Peer assessment has been demonstrated to be an effective educational intervention for health science students.\ud \ud Aims: This study aims to give an overview of all instruments or questionnaires for peer assessments used in medical and allied health professional educational settings and their psychometric characteristics as described in literature.\ud \ud Methods: A systematic literature search was carried out using the electronic databases Pubmed, Embase, ERIC, PsycINFO and Web of Science, including all available inclusion dates up to May 2010.\ud \ud Results: Out of 2899 hits, 28 studies were included, describing 22 different instruments for peer assessment in mainly medical educational settings. Although most studies considered professional behaviour as a main subject of assessment and described peer assessment usually as an assessment tool, great diversity was found in educational settings and application of peer assessment, dimensions or constructs as well as number of items and scoring system per questionnaire, and in psychometric characteristics.\ud \ud Conclusions: Although quite a few instruments of peer assessment have been identified, many questionnaires did not provide sufficient psychometric data. Still, the final choice of an instrument for educational purposes can only be justified by its sufficient reliability and validity as well as the discriminative and evaluative purposes of the assessment