18,844 research outputs found

    Applying Quality Improvement methods to address gaps in medicines reconciliation at transfers of care from an acute UK hospital

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    © Published by the BMJ Publishing Group Limited.Objectives Reliable reconciliation of medicines at admission and discharge from hospital is key to reducing unintentional prescribing discrepancies at transitions of healthcare. We introduced a team approach to the reconciliation process at an acute hospital with the aim of improving the provision of information and documentation of reliable medication lists to enable clear, timely communications on discharge. Setting An acute 400-bedded teaching hospital in London, UK. Participants The effects of change were measured in a simple random sample of 10 adult patients a week on the acute admissions unit over 18â €...months. Interventions Quality improvement methods were used throughout. Interventions included education and training of staff involved at ward level and in the pharmacy department, introduction of medication documentation templates for electronic prescribing and for communicating information on medicines in discharge summaries co-designed with patient representatives. Results Statistical process control analysis showed reliable documentation (complete, verified and intentional changes clarified) of current medication on 49.2% of patients discharge summaries. This appears to have improved (to 85.2%) according to a poststudy audit the year after the project end. Pharmacist involvement in discharge reconciliation increased significantly, and improvements in the numbers of medicines prescribed in error, or omitted from the discharge prescription, are demonstrated. Variation in weekly measures is seen throughout but particularly at periods of changeover of new doctors and introduction of new systems. Conclusions New processes led to a sustained increase in reconciled medications and, thereby, an improvement in the number of patients discharged from hospital with unintentional discrepancies (errors or omissions) on their discharge prescription. The initiatives were pharmacist-led but involved close working and shared understanding about roles and responsibilities between doctors, nurses, therapists, patients and their carers

    Measurement of opaque film thickness

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    The theoretical and experimental framework for thickness measurements of thin metal films by low frequency thermal waves is described. Although it is assumed that the films are opaque and the substrates are comparatively poor thermal conductors, the theory is easily extended to other cases of technological interest. A brief description is given of the thermal waves and the experimental arrangement and parameters. The usefulness of the technique is illustrated for making absolute measurements of the thermal diffusivities of isotropic substrate materials. This measurement on pure elemental solids provides a check on the three dimensional theory in the limiting case of zero film thickness. The theoretical framework is then presented, along with numerical calculations and corresponding experimental results for the case of copper films on a glass substrate

    Thermal wave detection and analysis of defects in structural composite materials

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    One criticism which can be leveled at thermal wave images is that their resolution is often less than that of the very best ultrasonic images of similar targets. This reduction of the resolution arises from the transverse diffusion of heat in the thermal waves reflected from the subsurface defects in the sample. In this paper we describe a technique for removing the blurring of pulsed thermal wave images of planar defects through the reconstruction of the shape of the scatterer by use of inverse scattering techniques. Although the method at present is restricted to planar defects, this special class of defects includes delaminations and disbonds in layered materials, defects which are of great interest to a variety of industries. Therefore, the availability of a reconstruction algorithm provides a solution to an important problem in nondestructive evaluation. The algorithm produced we have developed is quite simple and very effective when it is applied to thermal wave images of such defects. The idea behind the design of the model is the manipulation of the equations of thermal wave scattering theory in such a way that the scattered wave at the surface of the sample ends up being expressed as a convolution of a “heat spread” function, with a function which describes the shape of the scatterer. The Fourier transform of the surface temperature contrast (the contrast in the image is essentially just a representation of the scattered wave) can then be expressed as a simple product of the Fourier transform of the heat spread function and the Fourier transform of the shape function of the scatterer. In principle, application of the algorithm consists of performing a two-dimensional spatial Fast Fourier Transform (FFT) on the experimental image of the (unknown) scatterer, dividing the resulting Fourier transform by the transform of the (known) theoretical heat spread function, and finally doing an inverse FFT to obtain the shape of the scatterer

    Ginzburg-Landau theory of crystalline anisotropy for bcc-liquid interfaces

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    The weak anisotropy of the interfacial free-energy γ\gamma is a crucial parameter influencing dendritic crystal growth morphologies in systems with atomically rough solid-liquid interfaces. The physical origin and quantitative prediction of this anisotropy are investigated for body-centered-cubic (bcc) forming systems using a Ginzburg-Landau theory where the order parameters are the amplitudes of density waves corresponding to principal reciprocal lattice vectors. We find that this theory predicts the correct sign, γ100>γ110\gamma_{100}>\gamma_{110}, and magnitude, (γ100γ110)/(γ100+γ110)1(\gamma_{100}-\gamma_{110}) / (\gamma_{100}+\gamma_{110})\approx 1%, of this anisotropy in good agreement with the results of MD simulations for Fe. The results show that the directional dependence of the rate of spatial decay of solid density waves into the liquid, imposed by the crystal structure, is a main determinant of anisotropy. This directional dependence is validated by MD computations of density wave profiles for different reciprocal lattice vectors for {110}\{110\} crystal faces. Our results are contrasted with the prediction of the reverse ordering γ100<γ110\gamma_{100}<\gamma_{110} from an earlier formulation of Ginzburg-Landau theory [Shih \emph{et al.}, Phys. Rev. A {\bf 35}, 2611 (1987)].Comment: 9 pages, 5 figure

    Low-momentum nucleon-nucleon interaction and shell-model calculations

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    We discuss the use of the low-momentum nucleon-nucleon NN interaction V-low-k in the derivation of the shell-model effective interaction and emphasize its practical value as an alternative to the Brueckner G-matrix method. We present some selected results of our current study of exotic nuclei around closed shells, which have been obtained starting from the CD-Bonn potential. We also show some results of calculations performed with different phase-shift equivalent NN potentials, and discuss the effect of changes in the cutoff momentum which defines the V-low-k potential.Comment: 5 pages, 5 figures, 1 table, Talk presented at CDN05, 31 Jan - 4 Feb 2005, University of Tokyo, Japa

    Low Momentum Nucleon-Nucleon Interactions and Shell-Model Calculations

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    In the last few years, the low-momentum nucleon-nucleon (NN) interaction V-low-k derived from free-space NN potentials has been successfully used in shell-model calculations. V-low-k is a smooth potential which preserves the deuteron binding energy as well as the half-on-shell T-matrix of the original NN potential up to a momentum cutoff Lambda. In this paper we put to the test a new low-momentum NN potential derived from chiral perturbation theory at next-to-next-to-next-to-leading order with a sharp low-momentum cutoff at 2.1 fm-1. Shell-model calculations for the oxygen isotopes using effective hamiltonians derived from both types of low-momentum potential are performed. We find that the two potentials show the same perturbative behavior and yield very similar results.Comment: 8 pages, 8 figures, to be published in Physical Review

    Hermitian quark mass matrices with four texture zeros

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    We provide a complete and systematic analysis of hermitian, hierarchical quark mass matrices with four texture zeros. Using triangular mass matrices, each pattern of texture zeros is readily shown to lead to a definite relation between the CKM parameters and the quark masses. Nineteen pairs are found to be consistent with present data, and one other is marginally acceptable. In particular, no parallel structure between the up and down mass matrices is found to be favorable with data.Comment: 18 pages, no figure, references [8] and [10] adde

    Self-consistent approach for the quantum confined Stark effect in shallow quantum wells

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    A computationally efficient, self-consistent complex scaling approach to calculating characteristics of excitons in an external electric field in quantum wells is introduced. The method allows one to extract the resonance position as well as the field-induced broadening for the exciton resonance. For the case of strong confinement the trial function is represented in factorized form. The corresponding coupled self-consistent equations, which include the effective complex potentials, are obtained. The method is applied to the shallow quantum well. It is shown that in this case the real part of the effective exciton potential is insensitive to changes of external electric field up to the ionization threshold, while the imaginary part has non-analytical field dependence and small for moderate electric fields. This allows one to express the exciton quasi-energy at some field through the renormalized expression for the zero-field bound state.Comment: 13 pages, RevTeX4, 6 figure

    Rigorous treatment of electrostatics for spatially varying dielectrics based on energy minimization

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    A novel energy minimization formulation of electrostatics that allows computation of the electrostatic energy and forces to any desired accuracy in a system with arbitrary dielectric properties is presented. An integral equation for the scalar charge density is derived from an energy functional of the polarization vector field. This energy functional represents the true energy of the system even in non-equilibrium states. Arbitrary accuracy is achieved by solving the integral equation for the charge density via a series expansion in terms of the equation's kernel, which depends only on the geometry of the dielectrics. The streamlined formalism operates with volume charge distributions only, not resorting to introducing surface charges by hand. Therefore, it can be applied to any spatial variation of the dielectric susceptibility, which is of particular importance in applications to biomolecular systems. The simplicity of application of the formalism to real problems is shown with analytical and numerical examples.Comment: 27 pages, 5 figure

    Lorentz transformation and vector field flows

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    The parameter changes resulting from a combination of Lorentz transformation are shown to form vector field flows. The exact, finite Thomas rotation angle is determined and interpreted intuitively. Using phase portraits, the parameters evolution can be clearly visualized. In addition to identifying the fixed points, we obtain an analytic invariant, which correlates the evolution of parameters.Comment: 11 pages, 3 figures. Section IV revised and title change
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