1,727 research outputs found

    Reviews

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    Review of Exploring the Underground Economy: Studies of Illegal and Unreported Activity, Human Resource Management: a Critical Text, Personnel Management: a Comprehensive Guide to Theory and Practice in Britain and Reform at Work: Workplace Change and the New Industrial Order and Workplace Reform and Enterprise Bargaining: Issues, Cases and Trend

    Complex patterns of spontaneous initiations and terminations of reentrant circulation in a loop of cardiac tissue

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    A two-component model is developed that consists of a discrete loop of cardiac cells that circulates action potentials together with a cardiac pacing mechanism. Physiological properties of cells such as restitutions of refractoriness and of conduction velocity are given via experimentally measured functions. The dynamics of circulating pulses and their interactions with the pacer are regulated by two threshold relations. Patterns of spontaneous initiations and terminations of reentry (SITR) generated by this system are studied through numerical simulations and analytical observations. These patterns can be regular or irregular; causes of irregularities are identified as the threshold bistability of reentrant circulation (T-bistability) and in some cases, also phase-resetting interactions with the pacer.Comment: 27 pages, 10 figures, 61 references; A version of this paper (same results) is to appear in the Journal of Theoretical Biology; arXiv V2 adds helpful commments to facilitate reading and corrects minor errors in presentatio

    Asymptotic Giant Branch Variables in the Galaxy and the Local Group

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    AGB variables, particularly the large amplitude Mira type, are a vital step on the distance scale ladder. They will prove particularly important in the era of space telescopes and extremely large ground-based telescopes with adaptive optics, which will be optimized for infrared observing. Our current understanding of the distances to these stars is reviewed with particular emphasis on improvements that came from Hipparcos as well as on recent work on Local Group galaxies. In addition to providing the essential calibration for extragalactic distances Gaia may also provide unprecedented insight into the poorly understood mass-loss process itself.Comment: Accepted for publication in Astrophysics and Space Science. From a presentation at the conference "The Fundamental Cosmic Distance Scale: State of the Art and Gaia Perspective, Naples May 2011. 8 Pages, 9 Figure

    Sub-wavelength diffraction-free imaging with low-loss metal-dielectric multilayers

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    We demonstrate numerically the diffraction-free propagation of sub-wavelength sized optical beams through simple elements built of metal-dielectric multilayers. The proposed metamaterial consists of silver and a high refractive index dielectric, and is designed using the effective medium theory as strongly anisotropic and impedance matched to air. Further it is characterised with the transfer matrix method, and investigated with FDTD. The diffraction-free behaviour is verified by the analysis of FWHM of PSF in the function of the number of periods. Small reflections, small attenuation, and reduced Fabry Perot resonances make it a flexible diffraction-free material for arbitrarily shaped optical planar elements with sizes of the order of one wavelength.Comment: 5 pages, 4 figure

    <i>InSpectra</i> - A platform for identifying emerging chemical threats

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    Non-target analysis (NTA) employing high-resolution mass spectrometry (HRMS) coupled with liquid chromatography is increasingly being used to identify chemicals of biological relevance. HRMS datasets are large and complex making the identification of potentially relevant chemicals extremely challenging. As they are recorded in vendor-specific formats, interpreting them is often reliant on vendor-specific software that may not accommodate advancements in data processing. Here we present InSpectra, a vendor independent automated platform for the systematic detection of newly identified emerging chemical threats. InSpectra is web-based, open-source/access and modular providing highly flexible and extensible NTA and suspect screening workflows. As a cloud-based platform, InSpectra exploits parallel computing and big data archiving capabilities with a focus for sharing and community curation of HRMS data. InSpectra offers a reproducible and transparent approach for the identification, tracking and prioritisation of emerging chemical threats

    Physical and electrical characteristics of EDM debris

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    AbstractIn EDM, debris plays a key role in the electrical conditions of the discharge gap prior to each spark. Despite this, analysis of debris at all length-scales has not yet been performed, and therefore the nature of debris produced by electrical discharge processes is not fully understood. In this study debris created by the machining of two electrode materials set as negative polarity, silicon and titanium carbide, was centrifuged and imaged using SEM and TEM. From this analysis it was shown that electrode debris is 1nm or lower and up to 10Îźm in size. Population analysis of the particle size distribution was used to inform an electric field model based on a lattice Boltzmann method framework, simulating the effect of the presence of such debris on the electric field strength. This method is shown to be able to capture the local variation of the electric field and predict qualitatively the correct trend of the electric field strength increasing against the debris concentration. Such data is important for prediction and control of discharge gap size, as well as understanding the impact of a build-up of debris on uncontrolled sparking

    Practising social justice: Community organisations, what matters and what counts

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    This thesis investigates the situated knowing-in-practice of locally-based community organisations, and studies how this practice knowledge is translated and contested in inter-organisational relations in the community services field of practices. Despite participation in government-led consultation processes, community organisations express frustration that the resulting policies and plans inadequately take account of the contributions from their practice knowledge. The funding of locally-based community organisations is gradually diminishing in real terms and in the competitive tendering environment, large nationally-based organisations often attract the new funding sources. The concern of locally-based community organisations is that the apparent lack of understanding of their distinctive practice knowing is threatening their capacity to improve the well-being of local people and their communities. In this study, I work with practitioners, service participants and management committee members to present an account of their knowing-in-practice, its character and conditions of efficacy; and then investigate what happens when this local practice knowledge is translated into results-based accountability (RBA) planning with diverse organisations and institutions. This thesis analyses three points of observation: knowing in a community of practitioners; knowing in a community organisation and knowing in the community services field of practices. In choosing these points of observation, the inquiry explores some of the relations and intra-actions from the single organisation to the institutional at a time when state government bureaucracy has mandated that community organisations implement RBA to articulate outcomes that can be measured by performance indicators. A feminist, performative, relational practice-based approach employs participatory action research to achieve an enabling research experience for the participants. It aims to intervene strategically to enhance recognition of the distinctive contributions of community organisations’ practice knowledge. This thesis reconfigures understandings of the roles, contributions and accountabilities of locally-based community organisations. Observations of situated practices together with the accounts of workers and service participants demonstrate how community organisations facilitate service participants’ struggles over social justice. A new topology for rethinking social justice as processual and practice-based is developed. It demonstrates how these struggles are a dynamic complex of iteratively-enfolded practices of respect and recognition, redistribution and distributive justice, representation and participation, belonging and inclusion. The focus on the practising of social justice in this thesis offers an alternative to the neo-liberal discourse that positions community organisations as sub-contractors accountable to government for delivering measurable outputs, outcomes and efficiencies in specified service provision contracts. The study shows how knowing-in-practice in locally-based community organisations contests the representational conception of knowledge inextricably entangled with accountability and performance measurement apparatus such as RBA. Further, it suggests that practitioner and service participant contributions are marginalised and diminished in RBA through the privileging of knowledge that takes an ‘expert’, quantifiable and calculative form. Thus crucially, harnessing local practice knowing requires re-imagining and enacting knowledge spaces that assemble and take seriously all relevant stakeholder perspectives, diverse knowledges and methods
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