481 research outputs found

    Optimal scheduling of reliability development activities

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    Probabilistic Safety Assessment and Management is a collection of papers presented at the PSAM 7 - ESREL '04 Conference in June 2004. The joint Conference provided a forum for the presentation of the latest developments in methodology and application of probabilistic and reliability methods in various industries. Innovations in methodology as well as practical applications in the areas of probabilistic safety assessment and of reliability analysis are presented in this six volume set. The aim of these applications is the optimisation of technological systems and processes from the perspective of a risk-informed safety management while also taking economic and environmental aspects into account. The joint Conference in particular achieved an enhanced communication, the sharing of experience and integration of approaches not only among the various industries but also on a truly global basis by bringing together leading experts from all over the world. Over the last four decades, contemporary researchers have continuously been working to provide modern societies with a systematic, self-consistent and coherent framework for making decisions on at least one class of risks, those stemming from modern technological applications. Most of the effort has been spent in developing methods and techniques for assessing the dependability of technological systems, and assessing or estimating the levels of safety and associated risks. A wide spectrum of engineering, natural and economic sciences has been involved in this assessment effort. The developments have moved beyond research endeavours, they have been applied and utilised in real socio-technical environments and have become established - while modern technology continues to present new challenges and to raise new questions. Consequently, Probabilistic Safety Assessment and Management covers both well-established practices and open issues in the fields addressed by the Conference, identifying areas where maturity has been reached and those where more development is needed. The papers reflect a wide variety of disciplines, such as principles and theory of reliability and risk analysis, systems modelling and simulation, consequence assessment, human and organisational factors, structural reliability methods, software reliability and safety, insights and lessons from risk studies and management/decision making. A diverse range of application areas are represented including aviation and space, chemical processing, civil engineering, energy, environment, information technology, legal, manufacturing, health care, defence, transportation and waste management

    The impact of heat on mortality and morbidity in the Greater Metropolitan Sydney Region: A case crossover analysis

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    Background: This study examined the association between unusually high temperature and daily mortality (1997-2007) and hospital admissions (1997-2010) in the Sydney Greater Metropolitan Region (GMR) to assist in the development of targeted health program

    An outbreak of measles in a rural Queensland town in 1997; an opportunity to assess vaccine effectiveness

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    Ab initio calculation of the neutron-proton mass difference

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    The existence and stability of atoms rely on the fact that neutrons are more massive than protons. The measured mass difference is only 0.14\% of the average of the two masses. A slightly smaller or larger value would have led to a dramatically different universe. Here, we show that this difference results from the competition between electromagnetic and mass isospin breaking effects. We performed lattice quantum-chromodynamics and quantum-electrodynamics computations with four nondegenerate Wilson fermion flavors and computed the neutron-proton mass-splitting with an accuracy of 300300 kilo-electron volts, which is greater than 00 by 55 standard deviations. We also determine the splittings in the Σ\Sigma, Ξ\Xi, DD and Ξcc\Xi_{cc} isospin multiplets, exceeding in some cases the precision of experimental measurements.Comment: 57 pages, 15 figures, 6 tables, revised versio

    Electromagnetic radiation from collisions at almost the speed of light: an extremely relativistic charged particle falling into a Schwarzschild black hole

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    We investigate the electromagnetic radiation released during the high energy collision of a charged point particle with a four-dimensional Schwarzschild black hole. We show that the spectra is flat, and well described by a classical calculation. We also compare the total electromagnetic and gravitational energies emitted, and find that the former is supressed in relation to the latter for very high energies. These results could apply to the astrophysical world in the case charged stars and small charged black holes are out there colliding into large black holes, and to a very high energy collision experiment in a four-dimensional world. In this latter scenario the calculation is to be used for the moments just after the black hole formation, when the collision of charged debris with the newly formed black hole is certainly expected. Since the calculation is four-dimensional, it does not directly apply to Tev-scale gravity black holes, as these inhabit a world of six to eleven dimensions, although our results should qualitatively hold when extrapolated with some care to higher dimensions.Comment: 6 pages, 2 figure

    Spatio-temporal genetic tagging of a cosmopolitan planktivorous shark provides insight to gene flow, temporal variation and site-specific re-encounters

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    Migratory movements in response to seasonal resources often influence population structure and dynamics. Yet in mobile marine predators, population genetic consequences of such repetitious behaviour remain inaccessible without comprehensive sampling strategies. Temporal genetic sampling of seasonally recurring aggregations of planktivorous basking sharks, Cetorhinus maximus, in the Northeast Atlantic (NEA) affords an opportunity to resolve individual re-encounters at key sites with population connectivity and patterns of relatedness. Genetic tagging (19 microsatellites) revealed 18% of re-sampled individuals in the NEA demonstrated inter/multi-annual site-specific re-encounters. High genetic connectivity and migration between aggregation sites indicate the Irish Sea as an important movement corridor, with a contemporary effective population estimate (Ne) of 382 (CI = 241–830). We contrast the prevailing view of high gene flow across oceanic regions with evidence of population structure within the NEA, with early-season sharks off southwest Ireland possibly representing genetically distinct migrants. Finally, we found basking sharks surfacing together in the NEA are on average more related than expected by chance, suggesting a genetic consequence of, or a potential mechanism maintaining, site-specific re-encounters. Long-term temporal genetic monitoring is paramount in determining future viability of cosmopolitan marine species, identifying genetic units for conservation management, and for understanding aggregation structure and dynamics

    Cognitive mechanisms associated with auditory sensory gating

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    Sensory gating is a neurophysiological measure of inhibition that is characterised by a reduction in the P50 event-related potential to a repeated identical stimulus. The objective of this work was to determine the cognitive mechanisms that relate to the neurological phenomenon of auditory sensory gating. Sixty participants underwent a battery of 10 cognitive tasks, including qualitatively different measures of attentional inhibition, working memory, and fluid intelligence. Participants additionally completed a paired-stimulus paradigm as a measure of auditory sensory gating. A correlational analysis revealed that several tasks correlated significantly with sensory gating. However once fluid intelligence and working memory were accounted for, only a measure of latent inhibition and accuracy scores on the continuous performance task showed significant sensitivity to sensory gating. We conclude that sensory gating reflects the identification of goal-irrelevant information at the encoding (input) stage and the subsequent ability to selectively attend to goal-relevant information based on that previous identification
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