The Muller F element (4.2 Mb, ~80 protein-coding genes) is an unusual autosome of Drosophila melanogaster; it is mostly heterochromatic with a low recombination rate. To investigate how these properties impact the evolution of repeats and genes, we manually improved the sequence and annotated the genes on the D. erecta, D. mojavensis, and D. grimshawi F elements and euchromatic domains from the Muller D element. We find that F elements have greater transposon density (25–50%) than euchromatic reference regions (3–11%). Among the F elements, D. grimshawi has the lowest transposon density (particularly DINE-1: 2% vs. 11–27%). F element genes have larger coding spans, more coding exons, larger introns, and lower codon bias. Comparison of the Effective Number of Codons with the Codon Adaptation Index shows that, in contrast to the other species, codon bias in D. grimshawi F element genes can be attributed primarily to selection instead of mutational biases, suggesting that density and types of transposons affect the degree of local heterochromatin formation. F element genes have lower estimated DNA melting temperatures than D element genes, potentially facilitating transcription through heterochromatin. Most F element genes (~90%) have remained on that element, but the F element has smaller syntenic blocks than genome averages (3.4–3.6 vs. 8.4–8.8 genes per block), indicating greater rates of inversion despite lower rates of recombination. Overall, the F element has maintained characteristics that are distinct from other autosomes in the Drosophila lineage, illuminating the constraints imposed by a heterochromatic milieu.

This retrospective observational study demonstrates that cervical extension improves the specificity but decreases sensitivity of Mallampati examination. The Mallampati evaluation should be performed with the cervical spine in the neutral position to maximize test sensitivity.

These articles were published by mistake in the May 2016 issue of BJA due to an administrative error. They were supposed to go into this special issue on Airway Management. The articles can be accessed free of charge at the following link

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Background Critical appraisals provide a method for establishing the status of an area of study or evaluating the effectiveness of literature within it. The purpose of this study was to review and appraise studies published in 2017 on medical education in anesthesiology and to provide summaries of the highest-quality medical education research articles in the field. Methods Three Ovid MEDLINE databases, Embase.com , Education Resources Information Center (ERIC), and PsycINFO, were searched followed by a manual review of articles published in the highest impact factor journals in both the fields of anesthesiology and medical education. Abstracts were double-screened and quantitative articles subsequently scored by three randomly assigned raters. Qualitative studies were scored by two raters. Two different rubrics were used for scoring quantitative and qualitative studies, both allowed for scores ranging from 1-25. Results A total of 864 unique citations were identified through the search criteria. Of those, 62 articles met the inclusion criteria, with 59 quantitative and three qualitative. The top 10 papers with the highest scores were reported and summarized. Discussion As the first article to critically review the literature available for education in anesthesiology, we hope that this study will serve as the first manuscript in an annual series that will help individuals involved in anesthesiology education gain an understanding of the highest-quality research in the field. Once this process is repeated, trends can be tracked and serve as a resource to educators and researchers in anesthesiology for years to come.