1,058 research outputs found
Chronic fatigue syndrome; an approach combining self-management with graded exercise to avoid exacerbations.
Controversy regarding the aetiology and treatment of patients with chronic fatigue syndrome (CFS) continues to affect the medical professions. The Cochrane collaboration advises practitioners to implement graded exercise therapy for CFS sufferers using cognitive behavioural principles. In contrast there is evidence that exercise can induce symptom exacerbations in CFS where too vigorous exercise/activity promotes immune dysfunction, which in turn increases symptoms in patients with CFS. When designing and implementing an exercise programme it is important to be aware of both these seemingly opposing view points in order to deliver a programme without any detrimental effects on CFS pathophysiology. Using evidence from both the biological and clinical sciences, the present manuscript explains that graded exercise therapy for people with CFS can be safely undertaken without detrimental effects to the immune system. Exercise programs should be designed to cater for individual physical capabilities and should also account for the fluctuating nature of symptoms commonly reported by people with CFS. In line with cognitive behaviourally and graded exercise-based strategies, self-management for people with CFS involves encouraging the patients to pace their activities and respect their physical and mental limitations with the ultimate aim of improving their everyday function
Reconstructed Rough Growing Interfaces; Ridgeline Trapping of Domain Walls
We investigate whether surface reconstruction order exists in stationary
growing states, at all length scales or only below a crossover length, . The later would be similar to surface roughness in growing crystal
surfaces; below the equilibrium roughening temperature they evolve in a
layer-by-layer mode within a crossover length scale , but are always
rough at large length scales. We investigate this issue in the context of KPZ
type dynamics and a checker board type reconstruction, using the restricted
solid-on-solid model with negative mono-atomic step energies. This is a
topology where surface reconstruction order is compatible with surface
roughness and where a so-called reconstructed rough phase exists in
equilibrium. We find that during growth, reconstruction order is absent in the
thermodynamic limit, but exists below a crossover length , and that this local order fluctuates critically. Domain walls become
trapped at the ridge lines of the rough surface, and thus the reconstruction
order fluctuations are slaved to the KPZ dynamics
Empirical models of manufacturer-retailer interaction: A review and agenda for future research.
Nonlinear sigma model study of a frustrated spin ladder
A model of two-leg spin-S ladder with two additional frustrating diagonal
exchange couplings J_{D}, J_{D}' is studied within the framework of the
nonlinear sigma model approach. The phase diagram has a rich structure and
contains 2S gapless phase boundaries which split off the boundary to the fully
saturated ferromagnetic phase when J_{D} and J_{D}' become different. For the
S=1/2 case, the phase boundaries are identified as separating two topologically
distinct Haldane-type phases discussed recently by Kim et al.
(cond-mat/9910023).Comment: revtex 4 pages, figures embedded (psfig
Distressed personality is associated with lower psychological well-being and life satisfaction, but not disability or disease activity in rheumatoid arthritis patients
The distressed personality type (“type D personality”) has been shown to be associated with low quality of life and higher morbidity and mortality in various patient groups. Because the role of type D personality is unknown in patients with rheumatoid arthritis (RA), the aim of the present study was to investigate the association of type D personality with aspects of quality of life and disease activity in RA patients. In addition, a potential buffering effect by accepting mindfulness was examined. Participants were 147 patients between 22 and 87 years of age. Patients completed relevant questionnaires at home and the disease activity score was determined. After controlling for potentially confounding variables, multivariate analyses of covariance showed an association of type D personality with a lower satisfaction with life (p < 0.001) and a lower psychological well-being (p < 0.001), but not disease activity in RA patients. Although mindfulness was associated with a higher satisfaction with life (p = 0.02) and positive mood (p = 0.01), it did not diminish the unfavourable associations between type D and well-being. In conclusion, although type D personality is related with lower well-being, it does not seem to be associated with disability or disease activity in RA patients
An exact universal amplitude ratio for percolation
The universal amplitude ratio for percolation in two
dimensions is determined exactly using results for the dilute A model in regime
1, by way of a relationship with the q-state Potts model for q<4.Comment: 5 pages, LaTeX, submitted to J. Phys. A. One paragraph rewritten to
correct error
The continuum limit of the integrable open XYZ spin-1/2 chain
We show that the continuum limit of the integrable XYZ spin-1/2 chain on a
half-line gives rise to the boundary sine-Gordon theory using the perturbation
method.Comment: 8pages, LaTeX; typos in eq.(11) removed, one in reference correcte
Disordered Flat Phase and Phase Diagram for Restricted Solid on Solid Models of Fcc(110) Surfaces
We discuss the results of a study of restricted solid-on-solid models for fcc
(110) surfaces. These models are simple modifications of the exactly solvable
BCSOS model, and are able to describe a missing-row reconstructed
surface as well as an unreconstructed surface. They are studied in two
different ways. The first is by mapping the problem onto a quantum spin-1/2
one-dimensional hamiltonian of the Heisenberg type, with competing
couplings. The second is by standard Monte Carlo simulations. We find phase
diagrams with the following features, which we believe to be quite generic: (i)
two flat, ordered phases (unreconstructed and missing-row reconstructed); a
rough, disordered phase; an intermediate disordered flat (DF) phase,
characterized by monoatomic steps, whose physics is shown to be akin to that of
a dimer spin state. (ii) a transition line from the reconstructed
phase to the DF phase showing exponents which appear to be close, within our
numerical accuracy, to the 2D-Ising universality class. (iii) a critical
(preroughening) line with variable exponents, separating the unreconstructed
phase from the DF phase. Possible signatures and order parameters of the DF
phase are investigated.Comment: Revtex (22 pages) + 15 figures (uuencoded file
Ferrimagnetic and Long Period Antiferromagnetic Phases in High Spin Heisenberg Chains with D-Modulation
The ground state properties of the high spin Heisenberg chains with
alternating single site anisotropy are investigated by means of the numerical
exact daigonaization and DMRG method. It is found that the ferrimagnetic state
appears between the Haldane phase and period doubled N\'eel phase for the
integer spin chains. On the other hand, the transition from the
Tomonaga-Luttinger liquid state into the ferrimagnetic state takes place for
the half-odd-integer spin chains. In the ferrimagnetic phase, the spontaneous
magnetization varies continuously with the modulation amplitude of the single
site anisotropy. Eventually, the magnetization is locked to fractional values
of the saturated magnetization. These fractional values satisfy the
Oshikawa-Yamanaka-Affleck condition. The local spin profile is calculated to
reveal the physical nature of each state. In contrast to the case of
frustration induced ferrimagnetism, no incommensurate magnetic superstructure
is found.Comment: 5 pages, 7 figure
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