1,112 research outputs found
Leading strategies in competitive on-line prediction
We start from a simple asymptotic result for the problem of on-line
regression with the quadratic loss function: the class of continuous
limited-memory prediction strategies admits a "leading prediction strategy",
which not only asymptotically performs at least as well as any continuous
limited-memory strategy but also satisfies the property that the excess loss of
any continuous limited-memory strategy is determined by how closely it imitates
the leading strategy. More specifically, for any class of prediction strategies
constituting a reproducing kernel Hilbert space we construct a leading
strategy, in the sense that the loss of any prediction strategy whose norm is
not too large is determined by how closely it imitates the leading strategy.
This result is extended to the loss functions given by Bregman divergences and
by strictly proper scoring rules.Comment: 20 pages; a conference version is to appear in the ALT'2006
proceeding
Disease management projects and the Chronic CareModel in action: Baseline qualitative research
Background: Disease management programs, especially those based on the Chronic Care Model (CCM),are increasingly common in the Netherlands. While disease management programs have beenwell-researched quantitatively and economically, less qualitative research has been done. Theoverall aim of the study is to explore how disease management programs are implementedwithin primary care settings in the Netherlands; this paper focuses on the early developmentand implementation stages of five disease management programs in the primary care setting,based on interviews with project leadership teams. Methods: At the five sites, eleven semi-structured interviews were conducted at the five selected siteswith sixteen professionals interviewed; all project leaders were interviewed. The interviewsfocused on each project's chosen chronic illness (diabetes, eating disorders, COPD, multimorbidity,CVRM) and project plan, barriers to development and implementation, the projectleaders' action and reactions, as well as their roles and responsibilities, and diseasemanagement strategies. Analysis was inductive and interpretive, based on the content of theinterviews. After analysis, the results of this research on disease management programs andthe Chronic Care Model are viewed from a traveling technology framework. Results: This analysis uncovered four themes that can be mapped to disease management and theChronic Care Model: (1) changing the health care system, (2) patient-centered care, (3)technological systems and barriers, and (4) integrating projects into the larger system. Projectleaders discussed the paths, both direct and indirect, for transforming the health care systemto one that addresses chronic illness. Patient-centered care was highlighted as needed and aparadigm shift for many. Challenges with technological systems were pervasive.
Uptake of smoking cessation aids by smokers with a mental illness
Psychiatric inpatient settings represent an opportunity to initiate the provision of tobacco cessation care to smokers with a mental illness. This study describes the use of evidence-based smoking cessation aids proactively and universally offered to a population of psychiatric inpatients upon discharge, and explores factors associated with their uptake. Data derived from the conduct of a randomised controlled trial were analysed in terms of the proportion of participants (N = 378) that utilised cessation aids including project delivered telephone smoking cessation counselling and nicotine replacement therapy (NRT), and Quitline support. Factors associated with uptake of cessation aids were explored using multivariable logistic regression analyses. A large proportion of smokers utilised project delivered cessation counselling calls (89 %) and NRT (79 %), while 11 % used the Quitline. The majority accepted more than seven project delivered telephone cessation counselling calls (52 %), and reported NRT use during more than half of their accepted calls (70 %). Older age, higher nicotine dependence, irregular smoking and seeing oneself as a non-smoker were associated with uptake of behavioural cessation aids. Higher nicotine dependence was similarly associated with use of pharmacological aids, as was NRT use whilst an inpatient. Most smokers with a mental illness took up a proactive offer of aids to support their stopping smoking. Consideration by service providers of factors associated with uptake may increase further the proportion of such smokers who use evidence-based cessation aids and consequently quit smoking successfully
Atom gratings produced by large angle atom beam splitters
An asymptotic theory of atom scattering by large amplitude periodic
potentials is developed in the Raman-Nath approximation. The atom grating
profile arising after scattering is evaluated in the Fresnel zone for
triangular, sinusoidal, magneto-optical, and bichromatic field potentials. It
is shown that, owing to the scattering in these potentials, two
\QTR{em}{groups} of momentum states are produced rather than two distinct
momentum components. The corresponding spatial density profile is calculated
and found to differ significantly from a pure sinusoid.Comment: 16 pages, 7 figure
Phenomenological model of elastic distortions near the spin-Peierls transition in
A phenomenological model of the Landau type forms the basis for a study of
elastic distortions near the spin-Peierls transition in . The
atomic displacements proposed by Hirota {\it et al.} [Phys. Rev. Lett. {\bf
73}, 736 (1994)] are accounted for by the model which includes linear coupling
between and distortions. displacements are seen to be responsible
for anomalies in the elastic properties {\it at} , whereas incipient
distortions give rise to temperature dependence below . A discussion of
possible critical behavior is also made.Comment: 1 figure available upon reques
Nonparametric Information Geometry
The differential-geometric structure of the set of positive densities on a
given measure space has raised the interest of many mathematicians after the
discovery by C.R. Rao of the geometric meaning of the Fisher information. Most
of the research is focused on parametric statistical models. In series of
papers by author and coworkers a particular version of the nonparametric case
has been discussed. It consists of a minimalistic structure modeled according
the theory of exponential families: given a reference density other densities
are represented by the centered log likelihood which is an element of an Orlicz
space. This mappings give a system of charts of a Banach manifold. It has been
observed that, while the construction is natural, the practical applicability
is limited by the technical difficulty to deal with such a class of Banach
spaces. It has been suggested recently to replace the exponential function with
other functions with similar behavior but polynomial growth at infinity in
order to obtain more tractable Banach spaces, e.g. Hilbert spaces. We give
first a review of our theory with special emphasis on the specific issues of
the infinite dimensional setting. In a second part we discuss two specific
topics, differential equations and the metric connection. The position of this
line of research with respect to other approaches is briefly discussed.Comment: Submitted for publication in the Proceedings od GSI2013 Aug 28-30
2013 Pari
Proton polarizability contribution to the hyperfine splitting in muonic hydrogen
The contribution of the proton polarizability to the ground state hyperfine
splitting in muonic hydrogen is evaluated on the basis of modern experimental
and theoretical results on the proton polarized structure functions. The value
of this correction is equal to 4.6(8)\cdot 10^{-4} times the Fermi splitting
E_F.Comment: 10 pages (revtex), 5 figure
Enhanced stability of layered phases in parallel hard-spherocylinders due to the addition of hard spheres
There is increasing evidence that entropy can induce microphase separation in
binary fluid mixtures interacting through hard particle potentials. One such
phase consists of alternating two dimensional liquid-like layers of rods and
spheres. We study the transition from a uniform miscible state to this ordered
state using computer simulations and compare results to experiments and theory.
We conclude that (1) there is stable entropy driven microphase separation in
mixtures of parallel rods and spheres, (2) adding spheres smaller then the rod
length decreases the total volume fraction needed for the formation of a
layered phase, therefore small spheres effectively stabilize the layered phase;
the opposite is true for large spheres and (3) the degree of this stabilization
increases with increasing rod length.Comment: 11 pages, 9 figures. Submitted to Phys. Rev. E. See related website
http://www.elsie.brandeis.ed
The management of cardiovascular disease in the Netherlands: analysis of different programmes
Background: Disease management programmes are increasingly used to improve the efficacy and effectiveness of chronic care delivery.
But, disease management programme development and implementation is a complex undertaking that requires effective decision-making.
Choices made in the earliest phases of programme development are crucial, as they ultimately impact costs, outcomes and sustainability.
Methods: To increase our understanding of the choices that primary healthcare practices face when implementing such programmes and
to stimulate successful implementation and sustainability, we compared the early implementation of eight cardiovascular disease management
programmes initiated and managed by healthcare practices in various regions of the Netherlands. Using a mixed-methods design, we
identified differences in and challenges to programme implementation in terms of context, patient characteristics, disease management
level, healthcare utilisation costs, development costs and health-related quality of life.
Results: Shifting to a multidisciplinary, patient-centred care pathway approach to disease management is demanding for organisations,
professionals and patients, and is especially vulnerable when sustainable change is the goal. Funding is an important barrier to sustainable
implementation of cardiovascular disease management programmes, although development costs of the individual programmes varied
considerably in relation to the length of the development period. The large number of professionals involved in combination with duration
of programme development was the largest cost drivers. While Information and Communication Technology systems to support the new
care pathways did not directly contribute to higher costs, delays in implementation indirectly did.
Conclusions: Developing and implementing cardiovascular disease management programmes is time-consuming and challenging. Multidisciplinary,
patient-centred care demands multifaceted changes in routine care. As care pathways become more complex, they also
become more expensive. Better preparedness and training can prevent unnecessary delays during the implementation period and are crucial
to reducing costs
Evaluatie van disease management programma's in Nederland
In het ZonMw programma ‘Disease Management Chronische Ziekten’ (DMCZ) zijn 22 praktijkprojecten ontwikkeld, gevolgd en geëvalueerd. Deze ZonMw-praktijkprojecten hadden een looptijd van ongeveer drie jaar. Gedurende deze periode zijn de projecten systematisch gevolgd op een aantal proces- en effectmaten en kosten-effectiviteit.
De verwachting is dat disease management programma's gebaseerd op Ed Wagner's chronische zorgmodel bijdragen aan betere kwaliteit van chronische zorgverlening. Inzicht in de korte en lange termijn effecten van implementatie van dit type programma's voor verschillende chronische aandoeningen is echter nog schaars. [...
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