10,324 research outputs found
Methodological reflections on the evaluation of the implementation and adoption of national electronic health record systems
Copyright @ 2012, International Journal of Integrated Care (IJIC). This work is licensed under a (http://creativecommons.org/licenses/by/3.0) Creative Commons Attribution 3.0 Unported License.Introduction/purpose of presentation: Far-reaching policy commitments to information technology-centered transformations of healthcare systems have now been made in many countries. There is as yet little empirical evidence to justify such decisions, hence the need for rigorous independent evaluation of current implementation efforts. Such evaluations however pose a number of important challenges. This presentation has been designed as a part of a Panel based on our experience of evaluating the National Health Service’s (NHS) implementation of electronic health records (EHR) systems in hospitals throughout England. We discuss the methodological challenges encountered in planning and undertaking an evaluation of a program of this scale and reflect on why and how we adapted our evaluation approach—both conceptually and methodologically—in response to these challenges. Study design/population studied: Critical reflections on a multi-disciplinary and multi-facet independent evaluation of a national program to implement electronic health record systems into 12 ‘early wave’ NHS hospitals in England. Findings: Our initial plan was to employ a mixed methods longitudinal ‘before-during-after’ study design. We however found this unsustainable in the light of fluxes in policy, contractual issues and over-optimistic schedules for EHR deployments. More importantly, this research design failed adequately to address the core of multi-faceted evolving EHRs as understood by key stakeholders and as worked out in their distinct work settings. Thus conventional outcomes-centric evaluations may not easily scale-up when evaluating transformational programs and may indeed prove misleading. New assumptions concerning the implementation process of EHR need to be developed that recognize the constantly changing milieu of policy, product, projects and professions that are inherent to such national implementations. The approaches we subsequently developed substitute the positivist view that EHR initiatives are self-evident and self-contained interventions, which are amenable to traditional quantitative evaluations, to one that focuses on how they are understood by various stakeholders and made to work in specific contexts. These assumptions recast the role of evaluation towards an approach that explores and interprets processes of socio-technical change that surround EHR implementation and adoption as seen by multiple stakeholders. Conclusions and policy implications: There is likely to be an increase in politically-driven national programs of reform of healthcare based on information and communication technologies. Programs on such a scale are inherently complex with extended temporalities and extensive and dynamic sets of stakeholders. They are, in short, different and pose new evaluation challenges that previously formulated evaluation methods for health information systems cannot easily address. This calls for methodological innovation amongst research teams and their supporting bodies. We argue that evaluation of such system-wide transformation programs are likely to demand both breadth and depth of experience within a multidisciplinary research team, constant questioning of what is and what can be evaluated and how, and a particular way of working that emphasizes continuous dialogue and reflexivity. Making this transition is essential to enable evaluations that can usefully inform policy-making. Health policy experts urgently need to reassess the evaluation strategies they employ as they come to address national policies for system-wide transformation based on new electronic health infrastructures
Evidence for O(2) universality at the finite temperature transition for lattice QCD with 2 flavours of massless staggered quarks
We simulate lattice QCD with 2 flavours of massless quarks on lattices of
temporal extent N_t=8, to study the finite temperature transition from hadronic
matter to a quark-gluon plasma. A modified action which incorporates an
irrelevant chiral 4-fermion interaction is used, which allows simulations at
zero quark mass. We obtain excellent fits of the chiral condensates to the
magnetizations of a 3-dimensional O(2) spin model on lattices small enough to
model the finite size effects. This gives predictions for correlation lengths
and chiral susceptibilities from the corresponding spin-model quantities. These
are in good agreement with our measurements over the relevant range of
parameters. Binder cumulants are measured, but the errors are too large to draw
definite conclusions. From the properties of the O(2) spin model on the
relatively small lattices with which we fit our `data', we can see why earlier
attempts to fit staggered lattice data to leading-order infinite-volume scaling
functions, as well as finite size scaling studies, failed and led to erroneous
conclusions.Comment: 27 pages, Latex with 10 postscript figures. Some of the discussions
have been expanded to satisfy a referee. Typographical errors were correcte
Quasiperiodic spin-orbit motion and spin tunes in storage rings
We present an in-depth analysis of the concept of spin precession frequency
for integrable orbital motion in storage rings. Spin motion on the periodic
closed orbit of a storage ring can be analyzed in terms of the Floquet theorem
for equations of motion with periodic parameters and a spin precession
frequency emerges in a Floquet exponent as an additional frequency of the
system. To define a spin precession frequency on nonperiodic synchro-betatron
orbits we exploit the important concept of quasiperiodicity. This allows a
generalization of the Floquet theorem so that a spin precession frequency can
be defined in this case too. This frequency appears in a Floquet-like exponent
as an additional frequency in the system in analogy with the case of motion on
the closed orbit. These circumstances lead naturally to the definition of the
uniform precession rate and a definition of spin tune. A spin tune is a uniform
precession rate obtained when certain conditions are fulfilled. Having defined
spin tune we define spin-orbit resonance on synchro--betatron orbits and
examine its consequences. We give conditions for the existence of uniform
precession rates and spin tunes (e.g. where small divisors are controlled by
applying a Diophantine condition) and illustrate the various aspects of our
description with several examples. The formalism also suggests the use of
spectral analysis to ``measure'' spin tune during computer simulations of spin
motion on synchro-betatron orbits.Comment: 62 pages, 1 figure. A slight extension of the published versio
Slow dynamics at the smeared phase transition of randomly layered magnets
We investigate a model for randomly layered magnets, viz. a three-dimensional
Ising model with planar defects. The magnetic phase transition in this system
is smeared because static long-range order can develop on isolated rare spatial
regions. Here, we report large-scale kinetic Monte Carlo simulations of the
dynamical behavior close to the smeared phase transition which we characterize
by the spin (time) autocorrelation function. In the paramagnetic phase, its
behavior is dominated by Griffiths effects similar to those in magnets with
point defects. In the tail region of the smeared transition the dynamics is
even slower: the autocorrelation function decays like a stretched exponential
at intermediate times before approaching the exponentially small asymptotic
value following a power law at late times. Our Monte-Carlo results are in good
agreement with recent theoretical predictions based on optimal fluctuation
theory.Comment: 7 pages, 6 eps figures, final version as publishe
Exact clesed form of the return probability on the Bethe lattice
An exact closed form solution for the return probability of a random walk on
the Bethe lattice is given. The long-time asymptotic form confirms a previously
known expression. It is however shown that this exact result reduces to the
proper expression when the Bethe lattice degenerates on a line, unlike the
asymptotic result which is singular. This is shown to be an artefact of the
asymptotic expansion. The density of states is also calculated.Comment: 7 pages, RevTex 3.0, 2 figures available upon request from
[email protected], to be published in J.Phys.A Let
Quantum fidelity and quantum phase transitions in matrix product states
Matrix product states, a key ingredient of numerical algorithms widely
employed in the simulation of quantum spin chains, provide an intriguing tool
for quantum phase transition engineering. At critical values of the control
parameters on which their constituent matrices depend, singularities in the
expectation values of certain observables can appear, in spite of the
analyticity of the ground state energy. For this class of generalized quantum
phase transitions we test the validity of the recently introduced fidelity
approach, where the overlap modulus of ground states corresponding to slightly
different parameters is considered. We discuss several examples, successfully
identifying all the present transitions. We also study the finite size scaling
of fidelity derivatives, pointing out its relevance in extracting critical
exponents.Comment: 7 pages, 3 figure
Ising metamagnets in thin film geometry: equilibrium properties
Artificial antiferromagnets and synthetic metamagnets have attracted much
attention recently due to their potential for many different applications.
Under some simplifying assumptions these systems can be modeled by thin Ising
metamagnetic films. In this paper we study, using both the Wang/Landau scheme
and importance sampling Monte Carlo simulations, the equilibrium properties of
these films. On the one hand we discuss the microcanonical density of states
and its prominent features. On the other we analyze canonically various global
and layer quantities. We obtain the phase diagram of thin Ising metamagnets as
a function of temperature and external magnetic field. Whereas the phase
diagram of the bulk system only exhibits one phase transition between the
antiferromagnetic and paramagnetic phases, the phase diagram of thin Ising
metamagnets includes an additional intermediate phase where one of the surface
layers has aligned itself with the direction of the applied magnetic field.
This additional phase transition is discontinuous and ends in a critical end
point. Consequently, it is possible to gradually go from the antiferromagnetic
phase to the intermediate phase without passing through a phase transition.Comment: 8 figures, accepted for publication in Physical Review
A study to define meteorological uses and performance requirements for the Synchronous Earth Observatory Satellite
The potential meteorological uses of the Synchronous Earth Observatory Satellite (SEOS) were studied for detecting and predicting hazards to life, property, or the quality of the environment. Mesoscale meteorological phenonmena, and the observations requirements for SEOS are discussed along with the sensor parameters
On the finite-size behavior of systems with asymptotically large critical shift
Exact results of the finite-size behavior of the susceptibility in
three-dimensional mean spherical model films under Dirichlet-Dirichlet,
Dirichlet-Neumann and Neumann-Neumann boundary conditions are presented. The
corresponding scaling functions are explicitly derived and their asymptotics
close to, above and below the bulk critical temperature are obtained. The
results can be incorporated in the framework of the finite-size scaling theory
where the exponent characterizing the shift of the finite-size
critical temperature with respect to is smaller than , with
being the critical exponent of the bulk correlation length.Comment: 24 pages, late
Survival probabilities in time-dependent random walks
We analyze the dynamics of random walks in which the jumping probabilities
are periodic {\it time-dependent} functions. In particular, we determine the
survival probability of biased walkers who are drifted towards an absorbing
boundary. The typical life-time of the walkers is found to decrease with an
increment of the oscillation amplitude of the jumping probabilities. We discuss
the applicability of the results in the context of complex adaptive systems.Comment: 4 pages, 3 figure
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