5,205 research outputs found

    Knowledge flows, transfer, sharing and exchange

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    Proceedings of the 54th Hawaii International Conference on System Sciences | 202

    Identification and dynamics of a beneficial mutation in a long-term evolution experiment with Escherichia coli

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    <p>Abstract</p> <p>Background</p> <p>Twelve populations of <it>E. coli </it>were serially propagated for 20,000 generations in a glucose-supplemented minimal medium in order to study the dynamics of evolution. We sought to find and characterize one of the beneficial mutations responsible for the adaptation and other phenotypic changes, including increased cell size, in one of these populations.</p> <p>Results</p> <p>We used transposon-tagging followed by P1-transduction into the ancestor, screening for increased cell size and fitness, co-transduction analysis, and DNA sequencing. We identified a 1-bp insertion in the BoxG1 region located upstream of <it>glmUS</it>, an operon involved in cell-wall biosynthesis. When transduced into the ancestor, this mutation increased competitive fitness by about 5%. This mutation spread through its population of origin between 500 and 1500 generations. Mutations in this region were not found in the other 11 evolving populations, even after 20,000 generations.</p> <p>Conclusion</p> <p>The 1-bp insertion in the BoxG1 region near <it>glmUS </it>was demonstrably beneficial in the environment in which it arose. The absence of similar mutations in the other evolved populations suggests that they substituted other mutations that rendered this particular mutation unimportant. These results show the unpredictability of adaptive evolution, whereas parallel substitutions at other loci in these same populations reveal the predictability.</p

    Henry Cadell’s Experimental Researches in Mountain Building : their lessons for interpreting thrust systems and fold-thrust structures

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    Funding The Fold-Thrust Research Group has been funded by InterOil, Santos, OilSearch and NAGRA. The original compilation of Cadell’s researches was part of an outreach programme funded by BP. Acknowledgements RWHB is indebted to the late John Mendum for arranging access to Cadell’s notebooks and his field maps that were lodged in the then offices of the British Geological Survey in Murchison House, Edinburgh. This formed part of a collaboration with BGS and the development of the “Assynt’s Geology” website in the early 2000s. Many of the images from Cadell’s notebooks, including his experimental results, were part of this site. Regrettably it has not been maintained and is no longer accessible. Rectifying this loss of resource forms the motivation for this contribution. We thank Juergen Adam and an anonymous referee for construct reviews, together with James Hammerstein for shepherding the manuscript through the editing process, although of course the views expressed in this paper remain the responsibility of the authors alone.Peer reviewedPostprin

    Dialysis delayed is death prevented: A clinical perspective on the RENAAL study

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    A cross-sectional study of retired Great British Olympians (Berlin 1936 - Sochi 2014):Olympic career injuries, joint health in later life, and reasons for retirement from Olympic sport

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    The relationship between Olympic career sport injury and the long-term musculoskeletal health of the elite athlete remains unclear. This study describes the lifetime prevalence of medical attention injuries that occurred during training and/or competition as part of the athlete’s Olympic career, reasons for retirement from Olympic sport, and the point prevalence of pain and osteoarthritis (OA) among retired Great Britain’s (GB) Olympians
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