503 research outputs found

    alphabeta sequence of F is IS31

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    Previous studies have shown that there is a deoxyribonucleic acid (DNA) segment, of length 1.3 kb and denoted as the alphabeta sequence, which occurs twice on the F plasmid at corrdinates 93.2 to 94.5/OF kb and 13.7 to 15.0F kb. In the present investigation, heteroduplexes were prepared between a phage DNA carrying the insertion sequence IS3 and suitable F-prime DNAs. The hybrids formed show that IS3 is the same as alphabeta. This result plus previous studies support the view that: (i) the insertion sequence IS2 and IS3 occur on F and, in multiple copies, on the main bacterial chromosome of Escherichia coli K-12; and (ii)these IS sequences on the main bacterial chromosomes are hot spots for Hfr formation by reciprocal recombination with the corresponding sequences of F

    Results from an Einstein@Home search for continuous gravitational waves from Cassiopeia A, Vela Jr. and G347.3

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    We report results of the most sensitive search to date for periodic gravitational waves from Cassiopeia A, Vela Jr. and G347.3 with frequency between 20 and 1500 Hz. The search was made possible by the computing power provided by the volunteers of the Einstein@Home project and improves on previous results by a factor of 2 across the entire frequency range for all targets. We find no significant signal candidate and set the most stringent upper limits to date on the amplitude of gravitational wave signals from the target population, corresponding to sensitivity depths between 54 [1/Hz][1/ {\sqrt{\textrm{Hz}}}] and 83 [1/Hz][1/ {\sqrt{\textrm{Hz}}}], depending on the target and the frequency range. At the frequency of best strain sensitivity, near 172172 Hz, we set 90% confidence upper limits on the gravitational wave intrinsic amplitude of h090%1025h_0^{90\%}\approx 10^{-25}, probing ellipticity values for Vela Jr. as low as 3×1083\times 10^{-8}, assuming a distance of 200 pc

    FaSTrack: a Modular Framework for Real-Time Motion Planning and Guaranteed Safe Tracking

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    Real-time, guaranteed safe trajectory planning is vital for navigation in unknown environments. However, real-time navigation algorithms typically sacrifice robustness for computation speed. Alternatively, provably safe trajectory planning tends to be too computationally intensive for real-time replanning. We propose FaSTrack, Fast and Safe Tracking, a framework that achieves both real-time replanning and guaranteed safety. In this framework, real-time computation is achieved by allowing any trajectory planner to use a simplified \textit{planning model} of the system. The plan is tracked by the system, represented by a more realistic, higher-dimensional \textit{tracking model}. We precompute the tracking error bound (TEB) due to mismatch between the two models and due to external disturbances. We also obtain the corresponding tracking controller used to stay within the TEB. The precomputation does not require prior knowledge of the environment. We demonstrate FaSTrack using Hamilton-Jacobi reachability for precomputation and three different real-time trajectory planners with three different tracking-planning model pairs.Comment: Published in the IEEE Transactions on Automatic Contro

    Potential Impact of Time Trend of Life-Style Factors on Cardiovascular Disease Burden in China

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    Cardiovascular disease (CVD) is a leading cause of death in China. Evaluation of risk factors and their impacts on disease burden is important for future public health initiatives and policy making

    Do Chinese Traditional and Modern Cultures Affect Young Adults’ Moral Priorities?

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    Dramatic cultural change has occurred in Mainland China over the past four decades, yet little is known about how this cultural shift impacts Chinese peoples’ moral values. The present research aims to fill this gap by examining whether Chinese traditional and modern cultures influence young adults’ moral judgments. Study 1 investigated the relation between psychological traditionality/modernity and moral concerns. Results indicated that participants who strongly endorsed Chinese traditional culture prioritize relationship concern rather than justice concern. Study 2 used the cultural priming method and tested the effects of traditional and modern icons on moral concerns. Results suggested that participants who were primed with traditional or modern or neutral icons did not give priority to relationship or justice concern. Together, our findings provide initial empirical evidence on whether Chinese traditional and modern cultures shift the moral mindsets of bicultural young Chinese among alternative (and even competing) moral codes

    Bacterial expression of mutant argininosuccinate lyase reveals imperfect correlation of in - vitro enzyme activity with clinical phenotype in argininosuccinic aciduria

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    Background: The urea cycle defect argininosuccinate lyase (ASL) deficiency has a large spectrum of presentations from highly severe to asymptomatic. Enzyme activity assays in red blood cells or fibroblasts, although diagnostic of the deficiency, fail to discriminate between severe, mild or asymptomatic cases. Mutation/phenotype correlation studies are needed to characterize the effects of individual mutations on the activity of the enzyme. Methods: Bacterial in-vitro expression studies allowed the enzyme analysis of purified mutant ASL proteins p.I100T (c.299T > C), p.V178M (c.532G > A), p.E189G (c.566A > G), p.Q286R (c.857A > G), p.K315E (c.943A > G), p.R379C (c.1135C > T) and p.R385C (c.1153C > T) in comparison to the wildtype protein. Results: In the bacterial in-vitro expression system, ASL wild-type protein was successfully expressed. The known classical p.Q286R, the novel classical p.K315E and the known mutations p.I100T, p.E189G and p.R385C, which all have been linked to a mild phenotype, showed no significant residual activity. There was some enzyme activity detected with the p.V178M (5 % of wild-type) and p.R379C (10 % of wild-type) mutations in which Km values for argininosuccinic acid differed significantly from the wild-type ASL protein. Conclusion: The bacterially expressed enzymes proved that the mutations found in patients and studied here indeed are detrimental. However, as in the case of red cell ASL activity assays, some mutations found in genetically homozygous patients with mild presentations resulted in virtual loss of enzyme activity in the bacterial system, suggesting a more protective environment for the mutant enzyme in the liver than in the heterologous expression system and/or in the highly dilute assays utilized her
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