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

The Fat Body Transcriptomes of the Yellow Fever Mosquito Aedes aegypti, Pre- and Post- Blood Meal

BACKGROUND: The fat body is the main organ of intermediary metabolism in insects and the principal source of hemolymph proteins. As part of our ongoing efforts to understand mosquito fat body physiology and to identify novel targets for insect control, we have conducted a transcriptome analysis of the fat body of Aedes aegypti before and in response to blood feeding. RESULTS: We created two fat body non-normalized EST libraries, one from mosquito fat bodies non-blood fed (NBF) and another from mosquitoes 24 hrs post-blood meal (PBM). 454 pyrosequencing of the non-normalized libraries resulted in 204,578 useable reads from the NBF sample and 323,474 useable reads from the PBM sample. Alignment of reads to the existing reference Ae. aegypti transcript libraries for analysis of differential expression between NBF and PBM samples revealed 116,912 and 115,051 matches, respectively. De novo assembly of the reads from the NBF sample resulted in 15,456 contigs, and assembly of the reads from the PBM sample resulted in 15,010 contigs. Collectively, 123 novel transcripts were identified within these contigs. Prominently expressed transcripts in the NBF fat body library were represented by transcripts encoding ribosomal proteins. Thirty-five point four percent of all reads in the PBM library were represented by transcripts that encode yolk proteins. The most highly expressed were transcripts encoding members of the cathepsin b, vitellogenin, vitellogenic carboxypeptidase, and vitelline membrane protein families. CONCLUSION: The two fat body transcriptomes were considerably different from each other in terms of transcript expression in terms of abundances of transcripts and genes expressed. They reflect the physiological shift of the pre-feeding fat body from a resting state to vitellogenic gene expression after feeding