2,671 research outputs found

    The electromagnetic environment in CFC structures

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    Extensive measurements of induced voltages and currents were made using a CFC (carbon fiber composites) horizontal stabilizer from the A320 as a test bed. The work was done to investigate the efficacy of various protection schemes to reduce the magnitudes of the induced voltages and validate a computer program INDCAL. Results indicate that a good understanding of the various induced voltage mechanisms including the long wave effect due to current redistribution was obtained

    Measurements of some parameters of thermal sparks with respect to their ability to ignite aviation fuel/air mixtures

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    A method used to generate thermal sparks for experimental purposes and methods by which parameters of the sparks, such as speed, size, and temperature, were measured are described. Values are given of the range of such parameters within these spark showers. Titanium sparks were used almost exclusively, since it is particles of this metal which are found to be ejected during simulation tests to carbon fiber composite (CFC) joints. Tests were then carried out in which titanium sparks and spark showers were injected into JP4/(AVTAG F40) mixtures with air. Single large sparks and dense showers of small sparks were found to be capable of causing ignition. Tests were then repeated using ethylene/air mixtures, which were found to be more easily ignited by thermal sparks than the JP4/ air mixtures

    The relative performance of mutual and proprietary life insurance companies in the UK: an exploratory study

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    After discussing the main tenets of stakeholder and agency theory, the paper provides an exploratory empirical study of the relative performance of mutual and proprietary life insurance companies in the UK during the period 1995-96. The mutual companies included in the sample performed well relative to the proprietary companies in terms of their overall financial strength, annual surpluses and investment earnings. While the mutuals had slightly higher expense ratios than the proprietary companies, they were relatively more cost efficient and operated with potential economies of scale. There is also evidence that fund managers in mutuals perform at least as well on average as those in proprietary companies

    Complex domain interactions regulate stability and activity of closely related proneural transcription factors.

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    Characterising post-translational regulation of key transcriptional activators is crucial for understanding how cell division and differentiation are coordinated in developing organisms and cycling cells. One important mode of protein post-translational control is by regulation of half-life via ubiquitin-mediated proteolysis. Two key basic Helix-Loop-Helix transcription factors, Neurogenin 2 (Ngn2) and NeuroD, play central roles in development of the central nervous system but despite their homology, Ngn2 is a highly unstable protein whilst NeuroD is, by comparison, very stable. The basis for and the consequences of the difference in stability of these two structurally and functionally related proteins has not been explored. Here we see that ubiquitylation alone does not determine Ngn2 or NeuroD stability. By making chimeric proteins, we see that the N-terminus of NeuroD in particular has a stabilising effect, whilst despite their high levels of homology, the most conserved bHLH domains of these proneural proteins alone can confer significant changes in protein stability. Despite widely differing stabilities of Ngn2, NeuroD and the chimeric proteins composed of domains of both, there is little correlation between protein half-life and ability to drive neuronal differentiation. Therefore, we conclude that despite significant homology between Ngn2 and NeuroD, the regulation of their stability differs markedly and moreover, stability/instability of the proteins is not a direct correlate of their activity.Many thanks to Jon Vosper, Ryan Roark and Chris Hindley for helpful discussions. This work was supported by MRC Research Q23 Grant G0700758 (AP), and two MRC DTA Studentships (GM and LH).This is the published accepted manuscript distributed under a Creative Commons Attribution License 2.0, which can also be found on the publisher's website at: http://www.sciencedirect.com/science/article/pii/S0006291X14012017

    Comment on "A centrosome-independent role for gamma-TuRC proteins in the spindle assembly checkpoint"

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    Müller et al. (Reports, 27 October 2006, p. 654) showed that inhibition of the γ-tubulin ring complex (γ-TuRC) activates the spindle assembly checkpoint (SAC), which led them to suggest that γ-TuRC proteins play molecular roles in SAC activation. Because γ-TuRC inhibition leads to pleiotropic spindle defects, which are well known to activate kinetochore-derived checkpoint signaling, we believe that this conclusion is premature

    Findings and Recommendations of the Metropolitan Planning and Zoning Committee of the Jacksonville Chapter of the American Institute of Architects

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    Contained is a proposed bill that was introduced to the 1957 Florida Legislature concerning city development and zoning law
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