322 research outputs found
Evaluating case studies of community-oriented integrated care.
This paper summarises a ten-year conversation within London Journal of Primary Care about the nature of community-oriented integrated care (COIC) and how to develop and evaluate it. COIC means integration of efforts for combined disease-treatment and health-enhancement at local, community level. COIC is similar to the World Health Organisation concept of a Community-Based Coordinating Hub - both require a local geographic area where different organisations align their activities for whole system integration and develop local communities for health. COIC is a necessary part of an integrated system for health and care because it enables multiple insights into 'wicked problems', and multiple services to integrate their activities for people with complex conditions, at the same time helping everyone to collaborate for the health of the local population. The conversation concludes seven aspects of COIC that warrant further attention
Human ecological perspectives within a residential treatment setting for children
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44272/1/10566_2005_Article_BF01554427.pd
Critical Exponents of the Classical 3D Heisenberg Model: A Single-Cluster Monte Carlo Study
We have simulated the three-dimensional Heisenberg model on simple cubic
lattices, using the single-cluster Monte Carlo update algorithm. The expected
pronounced reduction of critical slowing down at the phase transition is
verified. This allows simulations on significantly larger lattices than in
previous studies and consequently a better control over systematic errors. In
one set of simulations we employ the usual finite-size scaling methods to
compute the critical exponents from a few
measurements in the vicinity of the critical point, making extensive use of
histogram reweighting and optimization techniques. In another set of
simulations we report measurements of improved estimators for the spatial
correlation length and the susceptibility in the high-temperature phase,
obtained on lattices with up to spins. This enables us to compute
independent estimates of and from power-law fits of their
critical divergencies.Comment: 33 pages, 12 figures (not included, available on request). Preprint
FUB-HEP 19/92, HLRZ 77/92, September 199
Quantum Monte Carlo and variational approaches to the Holstein model
Based on the canonical Lang-Firsov transformation of the Hamiltonian we
develop a very efficient quantum Monte Carlo algorithm for the Holstein model
with one electron. Separation of the fermionic degrees of freedom by a
reweighting of the probability distribution leads to a dramatic reduction in
computational effort. A principal component representation of the phonon
degrees of freedom allows to sample completely uncorrelated phonon
configurations. The combination of these elements enables us to perform
efficient simulations for a wide range of temperature, phonon frequency and
electron-phonon coupling on clusters large enough to avoid finite-size effects.
The algorithm is tested in one dimension and the data are compared with
exact-diagonalization results and with existing work. Moreover, the ideas
presented here can also be applied to the many-electron case. In the
one-electron case considered here, the physics of the Holstein model can be
described by a simple variational approach.Comment: 18 pages, 11 Figures, v2: one typo correcte
Modelling overdispersion with integer-valued moving average processes
A new first-order integer-valued moving average, INMA(1), model based
on the negative binomial thinning operation defined by Risti´c et al. [21] is proposed
and characterized. It is shown that this model has negative binomial (NB) marginal
distribution when the innovations follow a NB distribution and therefore it can be
used in situations where the data present overdispersion. Additionally, this model is
extended to the bivariate context. The Generalized Method of Moments (GMM) is
used to estimate the unknown parameters of the proposed models and the results of
a simulation study that intends to investigate the performance of the method show
that, in general, the estimates are consistent and symmetric. Finally, the proposed
model is fitted to a real dataset and the quality of the adjustment is evaluated.publishe
The random magnetic flux problem in a quantum wire
The random magnetic flux problem on a lattice and in a quasi one-dimensional
(wire) geometry is studied both analytically and numerically. The first two
moments of the conductance are obtained analytically. Numerical simulations for
the average and variance of the conductance agree with the theory. We find that
the center of the band plays a special role. Away from
, transport properties are those of a disordered quantum wire in
the standard unitary symmetry class. At the band center , the
dependence on the wire length of the conductance departs from the standard
unitary symmetry class and is governed by a new universality class, the chiral
unitary symmetry class. The most remarkable property of this new universality
class is the existence of an even-odd effect in the localized regime:
Exponential decay of the average conductance for an even number of channels is
replaced by algebraic decay for an odd number of channels.Comment: 16 pages, RevTeX; 9 figures included; to appear in Physical Review
Crossover from the chiral to the standard universality classes in the conductance of a quantum wire with random hopping only
The conductance of a quantum wire with off-diagonal disorder that preserves a
sublattice symmetry (the random hopping problem with chiral symmetry) is
considered. Transport at the band center is anomalous relative to the standard
problem of Anderson localization both in the diffusive and localized regimes.
In the diffusive regime, there is no weak-localization correction to the
conductance and universal conductance fluctuations are twice as large as in the
standard cases. Exponential localization occurs only for an even number of
transmission channels in which case the localization length does not depend on
whether time-reversal and spin rotation symmetry are present or not. For an odd
number of channels the conductance decays algebraically. Upon moving away from
the band center transport characteristics undergo a crossover to those of the
standard universality classes of Anderson localization. This crossover is
calculated in the diffusive regime.Comment: 22 pages, 9 figure
Critical Exponents, Hyperscaling and Universal Amplitude Ratios for Two- and Three-Dimensional Self-Avoiding Walks
We make a high-precision Monte Carlo study of two- and three-dimensional
self-avoiding walks (SAWs) of length up to 80000 steps, using the pivot
algorithm and the Karp-Luby algorithm. We study the critical exponents
and as well as several universal amplitude ratios; in
particular, we make an extremely sensitive test of the hyperscaling relation
. In two dimensions, we confirm the predicted
exponent and the hyperscaling relation; we estimate the universal
ratios , and (68\% confidence
limits). In three dimensions, we estimate with a
correction-to-scaling exponent (subjective 68\%
confidence limits). This value for agrees excellently with the
field-theoretic renormalization-group prediction, but there is some discrepancy
for . Earlier Monte Carlo estimates of , which were , are now seen to be biased by corrections to scaling. We estimate the
universal ratios and ; since , hyperscaling holds. The approach to
is from above, contrary to the prediction of the two-parameter
renormalization-group theory. We critically reexamine this theory, and explain
where the error lies.Comment: 87 pages including 12 figures, 1029558 bytes Postscript
(NYU-TH-94/09/01
Origins of the Ambient Solar Wind: Implications for Space Weather
The Sun's outer atmosphere is heated to temperatures of millions of degrees,
and solar plasma flows out into interplanetary space at supersonic speeds. This
paper reviews our current understanding of these interrelated problems: coronal
heating and the acceleration of the ambient solar wind. We also discuss where
the community stands in its ability to forecast how variations in the solar
wind (i.e., fast and slow wind streams) impact the Earth. Although the last few
decades have seen significant progress in observations and modeling, we still
do not have a complete understanding of the relevant physical processes, nor do
we have a quantitatively precise census of which coronal structures contribute
to specific types of solar wind. Fast streams are known to be connected to the
central regions of large coronal holes. Slow streams, however, appear to come
from a wide range of sources, including streamers, pseudostreamers, coronal
loops, active regions, and coronal hole boundaries. Complicating our
understanding even more is the fact that processes such as turbulence,
stream-stream interactions, and Coulomb collisions can make it difficult to
unambiguously map a parcel measured at 1 AU back down to its coronal source. We
also review recent progress -- in theoretical modeling, observational data
analysis, and forecasting techniques that sit at the interface between data and
theory -- that gives us hope that the above problems are indeed solvable.Comment: Accepted for publication in Space Science Reviews. Special issue
connected with a 2016 ISSI workshop on "The Scientific Foundations of Space
Weather." 44 pages, 9 figure
Physiological Responses and Physical Performance during Football in the Heat
PURPOSE: To examine the impact of hot ambient conditions on physical performance and physiological responses during football match-play. METHODS: Two experimental games were completed in temperate (∼ 21°C; CON) and hot ambient conditions (∼ 43°C; HOT). Physical performance was assessed by match analysis in 17 male elite players during the games and a repeated sprint test was conducted after the two game trials. Core and muscle temperature were measured and blood samples were obtained, before and after the games. RESULTS: Muscle and core temperatures were ∼ 1°C higher (P<0.05) in HOT (40.3 ± 0.1 and 39.5 ± 0.1°C, respectively) compared to CON (39.2 ± 0.1 and 38.3 ± 0.1°C). Average heart rate, plasma lactate concentration, body weight loss as well as post-game sprint performance were similar between the two conditions. Total game distance declined (P<0.05) by 7% and high intensity running (>14 km ⋅ h(-1)) by 26% in HOT compared to CON), but peak sprint speed was 4% higher (P<0.05) in HOT than in CON, while there were no differences in the quantity or length of sprints (>24 km ⋅ h(-1)) between CON and HOT. In HOT, success rates for passes and crosses were 8 and 9% higher (P<0.05), respectively, compared to CON. Delta increase in core temperature and absolute core temperature in HOT were correlated to total game distance in the heat (r = 0.85 and r = 0.53, respectively; P<0.05), whereas, total and high intensity distance deficit between CON and HOT were not correlated to absolute or delta changes in muscle or core temperature. CONCLUSION: Total game distance and especially high intensity running were lower during a football game in the heat, but these changes were not directly related to the absolute or relative changes in core or muscle temperature. However, peak sprinting speed and execution of successful passes and crosses were improved in the HOT condition
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