24,747 research outputs found

    Public contracts as accountability mechanisms: assuring quality in public healthcare in England and Wales

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    Contracting in the public sector is designed to enhance the accountability of service providers to their funders. The idea is that quality is improved by the use of service specifications, monitoring of performance and imposition of contractual sanctions. Socio-legal and economic theories of contract indicate that it will be difficult to make and enforce contracts to achieve this. The results of a study of National Health Services contracting in England and Wales are reported. We conclude that contracts alone are not sufficient to improve accountability – collibration of various regulatory measures (including more hierarchical mechanisms such as performance targets) is required

    Thermal Casimir drag in fluctuating classical fields

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    A uniformly moving inclusion which locally suppresses the fluctuations of a classical thermally excited field is shown to experience a drag force which depends on the dynamics of the field. It is shown that in a number of cases the linear friction coefficient is dominated by short distance fluctuations and takes a very simple form. Examples where this drag can occur are for stiff objects, such as proteins, nonspecifically bound to more flexible ones such as polymers and membranes.Comment: 4 pages RevTex, 2 figure

    Smoluchowski's equation for cluster exogenous growth

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    We introduce an extended Smoluchowski equation describing coagulation processes for which clusters of mass s grow between collisions with ds/dt=AsÎČds/dt=As^\beta. A physical example, dropwise condensation is provided, and its collision kernel K is derived. In the general case, the gelation criterion is determined. Exact solutions are found and scaling solutions are investigated. Finally we show how these results apply to nucleation of discs on a planeComment: Revtex, 4 pages (multicol.sty), 1 eps figures (uses epsfig

    Dealiasing techniques for high-order spectral element methods on regular and irregular grids

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    High-order methods are becoming increasingly attractive in both academia and industry, especially in the context of computational fluid dynamics. However, before they can be more widely adopted, issues such as lack of robustness in terms of numerical stability need to be addressed, particularly when treating industrial-type problems where challenging geometries and a wide range of physical scales, typically due to high Reynolds numbers, need to be taken into account. One source of instability is aliasing effects which arise from the nonlinearity of the underlying problem. In this work we detail two dealiasing strategies based on the concept of consistent integration. The first uses a localised approach, which is useful when the nonlinearities only arise in parts of the problem. The second is based on the more traditional approach of using a higher quadrature. The main goal of both dealiasing techniques is to improve the robustness of high order spectral element methods, thereby reducing aliasing-driven instabilities. We demonstrate how these two strategies can be effectively applied to both continuous and discontinuous discretisations, where, in the latter, both volumetric and interface approximations must be considered. We show the key features of each dealiasing technique applied to the scalar conservation law with numerical examples and we highlight the main differences in terms of implementation between continuous and discontinuous spatial discretisations

    Simple modeling of self-oscillation in Nano-electro-mechanical systems

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    We present here a simple analytical model for self-oscillations in nano-electro-mechanical systems. We show that a field emission self-oscillator can be described by a lumped electrical circuit and that this approach is generalizable to other electromechanical oscillator devices. The analytical model is supported by dynamical simulations where the electrostatic parameters are obtained by finite element computations.Comment: accepted in AP

    Antigenic and genetic evolution of contemporary swine H1 influenza viruses in the United States

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    Several lineages of influenza A viruses (IAV) currently circulate in North American pigs. Genetic diversity is further increased by transmission of IAV between swine and humans and subsequent evolution. Here, we characterized the genetic and antigenic evolution of contemporary swine H1N1 and H1N2 viruses representing clusters H1-α (1A.1), H1-ÎČ (1A.2), H1pdm (1A.3.3.2), H1-Îł (1A.3.3.3), H1-ÎŽ1 (1B.2.2), and H1-ÎŽ2 (1B.2.1) currently circulating in pigs in the United States. The ÎŽ1-viruses diversified into two new genetic clades, H1-ÎŽ1a (1B.2.2.1) and H1-ÎŽ1b (1B.2.2.2), which were also antigenically distinct from the earlier H1-ÎŽ1-viruses. Further characterization revealed that a few key amino acid changes were associated with antigenic divergence in these groups. The continued genetic and antigenic evolution of contemporary H1 viruses might lead to loss of vaccine cross-protection that could lead to significant economic impact to the swine industry, and represents a challenge to public health initiatives that attempt to minimize swine-to-human IAV transmission

    Charmonia enhancement in quark-gluon plasma with improved description of c-quarks phase-distribution

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    We present a dynamical model of heavy quark evolution in the quark-gluon plasma (QGP) based on the Fokker-Planck equation. We then apply this model to the case of central ultra-relativistic nucleus-nucleus collisions performed at RHIC and estimate the component of J/ψJ/\psi production (integrated and differential) stemming from c-cˉ\bar{c} pairs that are initially uncorrelated.Comment: contribution presented at SQM0

    Distinguishing an ejected blob from alternative flare models at the Galactic centre with GRAVITY

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    The black hole at the Galactic centre exhibits regularly flares of radiation, the origin of which is still not understood. In this article, we study the ability of the near-future GRAVITY infrared instrument to constrain the nature of these events. We develop realistic simulations of GRAVITY astrometric data sets for various flare models. We show that the instrument will be able to distinguish an ejected blob from alternative flare models, provided the blob inclination is >= 45deg, the flare brightest magnitude is 14 <= mK <= 15 and the flare duration is >= 1h30.Comment: 11 pages, 9 figures, accepted by MNRA

    The social geography of childcare: 'making up' the middle class child

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    Childcare is a condensate of disparate social forces and social processes. It is gendered and classed. It is subject to an excess of policy and political discourse. It is increasingly a focus for commercial exploitation. This is a paper reporting on work in progress in an ESRC funded research project (R000239232) on the choice and provision of pre-school childcare by middle class (service class) families in two contrasting London locations. Drawing on recent work in class analysis the paper examines the relationships between childcare choice, middle class fractions and locality. It suggests that on the evidence of the findings to date, there is some evidence of systematic differences between fractions in terms of values, perspectives and preferences for childcare, but a more powerful case for intra-class similarities, particularly when it comes to putting preferences into practice in the 'making up of a middle class child' through care and education
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