237 research outputs found

    Healthcare in continuum for an ageing population: national self monitoring or remote offshore monitoring for Australia?

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    Australia is a country, similar to other developed nations, confronting an ageing population with complex demographics. Ensuring continued healthcare for the ageing, while providing sufficient support for the already aged population requiring assistance, is at the forefront of the national agenda. Varied initiatives are with foci to leverage the advantages of lCTs leading to e-Health provisioning and assisted technologies. While these initiatives increasingly put budgetary constraints on local and federal governments, there is also a case for offshore resourcing of non-critical health services, to support, streamline and enhance the continuum of care, as the nation faces acute shortages of medical practitioners and nurses. However, privacy and confidentiality concerns in this context are a significant issue in Australia. In this paper, we take the position that if the National and state electronic health records system initiatives, are fully implemented, offshore resourcing can be a feasible complementary option resulting in a win-win situation of cutting costs and enabling the continuum of healthcare.<br /

    Comparative evaluation of converter-based compensation schemes for VSC systems to achieve full-range active power transfer in very weak grids

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    Voltage source converter (VSC) is the expected core technology that supports power system de-carbonization by allowing renewable energy development. However, with the increasing penetration of renewables and continuing decommissioning of thermal generators, challenges of integrating VSC-based systems into weak and even very weak ac grids become apparent. Therefore, this paper presents theoretical analysis describing the relationship between active power transfer range and weak grid factors of the generic VSC-grid system, and aims to identify the most effective way to allow the VSC to exchange the rated active power in both directions (±1 pu) with the weak grid. Thus, converter-based compensation is presented to extend the operation boundary and avoid voltage collapsing. Nevertheless, the effects of reactive current provision and series voltage compensations should be recognized; therefore, operational characteristics of two arrangements, namely, shunt and series VSC-based compensation schemes, are comparatively evaluated. In extremely weak grid cases, shunt compensation converter cannot ensure a full active power transfer range of the targeted VSC due to the inherent voltage limitation, whilst series compensation converter can assist the targeted VSC to achieve full-range active power transfer. Effectiveness and performance of the presented compensation methods during power reversal and ac fault are demonstrated with a typical extremely weak grid, and system boundaries with different schemes are given

    A novel converter station structure for improving multi-terminal HVDC system resiliency against AC and DC faults

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    In an effort to minimize the power disruption between a dc grid and ac grids that host power converters during ac and dc network faults, this paper proposes a novel converter station structure to improve ac and dc fault ride-through performance of the multi-terminal HVDC grid. The proposed structure consists of two independent ac and dc interfacing circuits, which are a half-bridge modular multilevel converter and a cascaded H-bridge (CHB) based energy storage system. Taking the advantages of high controllability and flexibility of the independent CHB converter and ease of integrating energy modules, a decoupled power relationship between the ac and dc sides is achieved, which is important for enhancing ac and dc fault performance. Operation of the proposed converter station under normal conditions and during ac and dc faults is explained, with the control system presented. Simulation validation of the proposed structure on a three-terminal HVDC grid confirms the enhanced performance, including the continuous operation during ac and dc faults with negligible power transfer disruption

    Anomaly-free vector perturbations with holonomy corrections in loop quantum cosmology

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    We investigate vector perturbations with holonomy corrections in the framework of loop quantum cosmology. Conditions to achieve anomaly freedom for these perturbations are found at all orders. This requires the introduction of counter-terms in the hamiltonian constraint. We also show that anomaly freedom requires the diffeomorphism constraint to hold its classical form when scalar matter is added although the issue of a vector matter source, required for full consistency, remains to be investigated. The gauge-invariant variable and the corresponding equation of motion are derived. The propagation of vector modes through the bounce is finally discussed.Comment: 16 pages, 1 figure. Matches version published in Class. Quantum Gra

    TeV-Scale Black Hole Lifetimes in Extra-Dimensional Lovelock Gravity

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    We examine the mass loss rates and lifetimes of TeV-scale extra dimensional black holes (BH) in ADD-like models with Lovelock higher-curvature terms present in the action. In particular we focus on the predicted differences between the canonical and microcanonical ensemble statistical mechanics descriptions of the Hawking radiation that results in the decay of these BH. In even numbers of extra dimensions the employment of the microcanonical approach is shown to generally lead to a significant increase in the BH lifetime as in case of the Einstein-Hilbert action. For odd numbers of extra dimensions, stable BH remnants occur when employing either description provided the highest order allowed Lovelock invariant is present. However, in this case, the time dependence of the mass loss rates obtained employing the two approaches will be different. These effects are in principle measurable at future colliders.Comment: 27 pages, 9 figs; Refs. and discussion adde

    Relative energetics and structural properties of zirconia using a self-consistent tight-binding model

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    We describe an empirical, self-consistent, orthogonal tight-binding model for zirconia, which allows for the polarizability of the anions at dipole and quadrupole levels and for crystal field splitting of the cation d orbitals. This is achieved by mixing the orbitals of different symmetry on a site with coupling coefficients driven by the Coulomb potentials up to octapole level. The additional forces on atoms due to the self-consistency and polarizabilities are exactly obtained by straightforward electrostatics, by analogy with the Hellmann-Feynman theorem as applied in first-principles calculations. The model correctly orders the zero temperature energies of all zirconia polymorphs. The Zr-O matrix elements of the Hamiltonian, which measure covalency, make a greater contribution than the polarizability to the energy differences between phases. Results for elastic constants of the cubic and tetragonal phases and phonon frequencies of the cubic phase are also presented and compared with some experimental data and first-principles calculations. We suggest that the model will be useful for studying finite temperature effects by means of molecular dynamics.Comment: to be published in Physical Review B (1 march 2000

    The All-Data-Based Evolutionary Hypothesis of Ciliated Protists with a Revised Classification of the Phylum Ciliophora (Eukaryota, Alveolata)

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    This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article's Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ The file attached is the published version of the article

    Loop quantum gravity: the first twenty five years

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    This is a review paper invited by the journal "Classical ad Quantum Gravity" for a "Cluster Issue" on approaches to quantum gravity. I give a synthetic presentation of loop gravity. I spell-out the aims of the theory and compare the results obtained with the initial hopes that motivated the early interest in this research direction. I give my own perspective on the status of the program and attempt of a critical evaluation of its successes and limits.Comment: 24 pages, 3 figure
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