1,419 research outputs found

    Development of reliability methodology for systems engineering. Volume III - Theoretical investigations - An approach to a class of reliability problems Final report

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    Random quantities from continuous time stochastic process with application to reliability and probabilit

    On certain functionals of normal processes Technical report no. 1

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    Probabilistic modeling and stochastic process investigations to provide measures of quality of performance and reliability for systems engineering - Chebyshev approximatio

    Identification of QuiP, the Product of Gene PA1032, as the Second Acyl-Homoserine Lactone Acylase of Pseudomonas aeruginosa PAO1

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    The relevance of the acyl homoserine lactone (acyl-HSL) quorum signals N-3-oxododecanoyl-homoserine lactone (3OC12HSL) and N-butanoyl-homoserine lactone to the biology and virulence of Pseudomonas aeruginosa is well investigated. Previously, P. aeruginosa was shown to degrade long-chain, but not short-chain, acyl-HSLs as sole carbon and energy sources (J. J. Huang, J.-I. Han, L.-H. Zhang, and J. R. Leadbetter, Appl. Environ. Microbiol. 69:5941-5949, 2003). A gene encoding an enzyme with acyl-HSL acylase activity, pvdQ (PA2385), was identified, but it was not required for acyl-HSL utilization. This indicated that P. aeruginosa encodes another acyl-HSL acylase, which we identify here. A comparison of total cell proteins of cultures grown with long-acyl acyl-HSLs versus other substrates implicated the involvement of a homolog of PvdQ, the product of gene PA1032, for which we propose the name QuiP. Transposon mutants of quiP were defective for growth when P. aeruginosa was cultured in medium containing decanoyl-HSL as a sole carbon and energy source. Complementation with a functional copy of quiP rescued this growth defect. When P. aeruginosa was grown in buffered lysogeny broth, constitutive expression of QuiP in P. aeruginosa led to decreased accumulations of the quorum signal 3OC12HSL, relative to the wild type. Heterologous expression of QuiP was sufficient to confer long-chain acyl-HSL acylase activity upon Escherichia coli. Examination of gene expression patterns during acyl-HSL-dependent growth of P. aeruginosa further supported the involvement of quiP in signal decay and revealed other genes also possibly involved. It is not yet known under which "natural" conditions quiP is expressed or how P. aeruginosa balances the expression of its quorum-sensing systems with the expression of its acyl-HSL acylase activities

    Vibration characteristics of 1/8-scale dynamic models of the space-shuttle solid-rocket boosters

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    Vibration tests and analyses of six 1/8 scale models of the space shuttle solid rocket boosters are reported. Natural vibration frequencies and mode shapes were obtained for these aluminum shell models having internal solid fuel configurations corresponding to launch, midburn (maximum dynamic pressure), and near endburn (burnout) flight conditions. Test results for longitudinal, torsional, bending, and shell vibration frequencies are compared with analytical predictions derived from thin shell theory and from finite element plate and beam theory. The lowest analytical longitudinal, torsional, bending, and shell vibration frequencies were within + or - 10 percent of experimental values. The effects of damping and asymmetric end skirts on natural vibration frequency were also considered. The analytical frequencies of an idealized full scale space shuttle solid rocket boosted structure are computed with and without internal pressure and are compared with the 1/8 scale model results

    Best Practice Description Document

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    This work received support and funding from • The BOHAB project (Biological Oceanography of Harmful Algal Blooms off the west coast of Ireland) through the National Development Plan 2000 – 2006 with the support of the Marine Institute and the Marine RTDI (Research, Technology, Development and Innovation) Measure, Productive Sector Operational Programme, Grant-aid Agreement No. ST/02/01. • the ASIMUTH project (Applied simulations and Integrated modelling for the understanding of toxic and harmful algal blooms) through the European Research Council under the European Union's Seventh Framework Programme (FP7/2007-2013) for Research and Technological Development - EC FP7 Programme, Space Theme, Grant Agreement No. 261860 • the MyOcean 2 project through the EC FP7 Programme, Space Theme, Grant Agreement No. 283367 • the AtlantOS project through the European Union's Horizon 2020 research and innovation programme, Grant Agreement No. 633211 • The PRIMROSE (Predicting the impact of regional scale events on the aquaculture sector) project, co-financed by the European Regional Development Fund through the Interreg Atlantic Area Programme, EAPA_182/2016 • The CoCliME (Co-development of climate services for adaptation to changing marine ecosystems) project is part of the European Research Area for Climate Services (ERA4CS), an ERA-NET initiated by JPI Climate, and funded by EPA (IE), ANR (FR), BMBF (DE), UEFISCDI (RO), RCN (NO) and FORMAS (SE), with co-funding by the European Union (Grant Agreement No. 690462).This document describes the procedural steps in creating an information product focused on toxic and harmful phytoplankton. The product is an online Harmful Algal Bloom (HAB) bulletin for aquaculturists, who can face serious operational challenges in the days after a HAB event. Data from satellite, numerical hydrodynamic models and In-situ ocean observations are organised and presented into visual information products. These products are enhanced through local expert evaluation and their interpretation is summarised in the bulletin. This document aims to provide both process overviews (the “what” of the Best Practice in producing the bulletins) and detail procedures (the “how” of the Best Practice”) so that the bulletins may be replicated in other geographic regions.European Commissio

    On smoothed probability density estimation for stationary processes

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    Aspects of estimation of the (marginal) probability density for a stationary sequence or continuous parameter process, are considered in this paper. Consistency and asymptotic distributional results are obtained using a class of smoothed function estimators including those of kernel type, under various decay of dependence conditions for the process. Some of the consistency results contain convergence rates which appear to be more delicate than those previously available, even for i.i.d. sequences

    Validation of a Single Inertial Sensor for Measuring Running Kinematics Overground During a Prolonged Run

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    This article is made available in accordance with the publisher's statement on Open access.Introduction: The purpose of this study was to validate acceleration data from a single inertial sensor containinga tri-axial accelerometer, whilst running overground during a prolonged run against a motion analysis system. Methods: An inertial sensor was placed on the low back of 10 runners who performed an 8 km run on a treadmill.To provide validation of the sensor, data were collected as runners ran along a runway through a motion analysis system at the beginning and throughout the run.Results: High levels of agreement between the two systems were found in the craniocaudal and mediolateral acceleration, with antero posterior having the least agreement with greatest Typical Error of the Estimate (0.66 sample points). Very high to extremely high correlations across all testing times were found in all three directions of accelerations (r=0.75 to 0.95). Heel strike and toe off events were identified in anteroposterior and craniocaudal acceleration, with high levels of agreement and extremely high correlations (r=0.99) between the two systems.Minimal variation and change in agreement and correlation between the data at each testing time were found. Discussion: This study provides evidence that a single inertial sensor placed on the low back is valid for measuring three-dimensional acceleration in overground running during a prolonged run. Further analysis identified specific events of heel strike and toe off and were comparable between the two systems. The minimal variation and change in agreement between the two systems during the run indicates the adherence method of the inertial sensor was suitable. Conclusions: The results of this study indicate that data collected from a single inertial sensor is highly correlated with simultaneous data collected using a motion analysis system, and has the capability to identify heelstrike and toe off events in overground running throughout a prolonged fatiguing run

    Convergence to extremal processes in random environments and extremal ageing in SK models

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    This paper extends recent results on aging in mean field spin glasses on short time scales, obtained by Ben Arous and Gun [2] in law with respect to the environment, to results that hold almost surely, respectively in probability, with respect to the environment. It is based on the methods put forward in Gayrard [8,9] and naturally complements Bovier and Gayrard [6].Comment: Revised version contains minor change
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