2,808 research outputs found

    Design diversity: an update from research on reliability modelling

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    Diversity between redundant subsystems is, in various forms, a common design approach for improving system dependability. Its value in the case of software-based systems is still controversial. This paper gives an overview of reliability modelling work we carried out in recent projects on design diversity, presented in the context of previous knowledge and practice. These results provide additional insight for decisions in applying diversity and in assessing diverseredundant systems. A general observation is that, just as diversity is a very general design approach, the models of diversity can help conceptual understanding of a range of different situations. We summarise results in the general modelling of common-mode failure, in inference from observed failure data, and in decision-making for diversity in development.

    Charmonium properties from lattice QCD + QED: hyperfine splitting, J/ψJ/\psi leptonic width, charm quark mass and aμca_{\mu}^c

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    We have performed the first nf=2+1+1n_f = 2+1+1 lattice QCD computations of the properties (masses and decay constants) of ground-state charmonium mesons. Our calculation uses the HISQ action to generate quark-line connected two-point correlation functions on MILC gluon field configurations that include u/du/d quark masses going down to the physical point, tuning the cc quark mass from MJ/ψM_{J/\psi} and including the effect of the cc quark's electric charge through quenched QED. We obtain MJ/ψMηcM_{J/\psi}-M_{\eta_c} (connected) = 120.3(1.1) MeV and interpret the difference with experiment as the impact on MηcM_{\eta_c} of its decay to gluons, missing from the lattice calculation. This allows us to determine ΔMηcannihiln\Delta M_{\eta_c}^{\mathrm{annihiln}} =+7.3(1.2) MeV, giving its value for the first time. Our result of fJ/ψ=f_{J/\psi}= 0.4104(17) GeV, gives Γ(J/ψe+e)\Gamma(J/\psi \rightarrow e^+e^-)=5.637(49) keV, in agreement with, but now more accurate than experiment. At the same time we have improved the determination of the cc quark mass, including the impact of quenched QED to give mc(3GeV)\overline{m}_c(3\,\mathrm{GeV}) = 0.9841(51) GeV. We have also used the time-moments of the vector charmonium current-current correlators to improve the lattice QCD result for the cc quark HVP contribution to the anomalous magnetic moment of the muon. We obtain aμc=14.638(47)×1010a_{\mu}^c = 14.638(47) \times 10^{-10}, which is 2.5σ\sigma higher than the value derived using moments extracted from some sets of experimental data on R(e+ehadrons)R(e^+e^- \rightarrow \mathrm{hadrons}). This value for aμca_{\mu}^c includes our determination of the effect of QED on this quantity, δaμc=0.0313(28)×1010\delta a_{\mu}^c = 0.0313(28) \times 10^{-10}.Comment: Added extra discussion on QED setup, some new results to study the effects of strong isospin breaking in the sea (including new Fig. 1) and a fit stability plot for the hyperfine splitting (new Fig. 7). Version accepted for publication in PR

    Enhanced Support for High Intensity Users of the Criminal Justice System – an evaluation of mental health nurse input into Integrated Offender Management Services in the North East of England

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    The current UK Government’s focus on the development of services to manage and support offenders with mental health problems has resulted in a number of innovative project developments. This research examines a service development in the North East of England which co-located Mental Health nurses with two Integrated Offender Management teams. While not solving all problems, the benefits of co-location were clear – although such innovations are now at risk from government changes which will make Integrated Offender Management the responsibility of new providers without compelling them to co-operate with health services

    Assessing Professionalism: A theoretical framework for defining clinical rotation assessment criteria

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    Although widely accepted as an important graduate competence, professionalism is a challenging outcome to define and assess. Clinical rotations provide an excellent opportunity to develop student professionalism through the use of experiential learning and effective feedback, but without appropriate theoretical frameworks, clinical teachers may find it difficult to identify appropriate learning outcomes. The adage “I know it when I see it” is unhelpful in providing feedback and guidance for student improvement, and criteria that are more specifically defined would help students direct their own development. This study sought first to identify how clinical faculty in one institution currently assess professionalism, using retrospective analysis of material obtained in undergraduate teaching and faculty development sessions. Subsequently, a faculty workshop was held in which a round-table type discussion sought to develop these ideas and identify how professionalism assessment could be improved. The output of this session was a theoretical framework for teaching and assessing professionalism, providing example assessment criteria and ideas for clinical teaching. This includes categories such as client and colleague interaction, respect and trust, recognition of limitations, and understanding of different professional identities. Each category includes detailed descriptions of the knowledge, skills, and behaviors expected of students in these areas. The criteria were determined by engaging faculty in the development of the framework, and therefore they should represent a focused development of criteria already used to assess professionalism, and not a novel and unfamiliar set of assessment guidelines. The faculty-led nature of this framework is expected to facilitate implementation in clinical teaching

    Directional wetting in anisotropic inverse opals

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    Porous materials display interesting transport phenomena due to the restricted motion of fluids within the nano- to micro-scale voids. Here, we investigate how liquid wetting in highly ordered inverse opals is affected by anisotropy in pore geometry. We compare samples with different degrees of pore asphericity and find different wetting patterns depending on the pore shape. Highly anisotropic structures are infiltrated more easily than their isotropic counterparts. Further, the wetting of anisotropic inverse opals is directional, with liquids filling from the side more easily. This effect is supported by percolation simulations as well as direct observations of wetting using time-resolved optical microscopy
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