2,374 research outputs found
Effects of active and passive warming of the foot sole on vibration perception thresholds
Objective
Skin temperatures are known to increase cutaneous sensitivity. However, it is unclear whether the amount of improved sensitivity differs depending on the protocol of heat application. Therefore, this study aimed to investigate the effects of active (treadmill walking) and passive (infrared radiator) warming of the foot sole on vibration perception thresholds.
Methods
Sixty healthy and injury-free subjects voluntarily participated in this study. Vibration perception thresholds (200 Hz) and plantar temperatures were measured at the hallux and 1st metatarsal head. In experiment 1, warming and mechanically stimulating the skin was achieved by walking on a treadmill for 30 min. In a follow-up study (experiment 2), external plantar heat was administered via an infrared radiator (30 min).
Results
In both experiments, increasing temperatures led to increased plantar sensitivity. However, the amount of improved sensitivity was greater in experiment 1, although plantar temperature increases were lower compared to experiment 2.
Conclusions
Warming in conjunction with mechanical stimulation seems to have a greater potential to enhance plantar sensitivity compared to external heat supply only.
Significance
The possible influence of mechanical stimulation and warming towards superior plantar afferent feedback highlights its importance regarding human posture and fall prevention
q-Deformed Superalgebras
The article deals with q-analogs of the three- and four-dimensional Euclidean
superalgebra and the Poincare superalgebra.Comment: 38 pages, LateX, no figures, corrected typo
Humanistic burden in schizophrenia: a literature review.
Abstract Objectives of the study and background Schizophrenia is a complex disease that affects 1% of the population. This disease has a considerable impact not only on patients' health and well-being but also on their surrounding environment. The costs of the disease's management remain large for individuals and society. While literature on the economic impact of schizophrenia is abundant, few studies have focused on its humanistic burden. This does not only concern patients, but also caregivers, relatives, neighbours and others in a patient's daily life. This burden appears through several dimensions, including treatment side effects and the impact on caregivers and features of the patient's environment. The aim of this review is to consider, compile and describe the humanistic burden of schizophrenia as documented in the literature. Materials and methods We conducted a literature review assessing the worldwide disease burden of schizophrenia, taking into account all humanistic burden topics. The search considered several databases, including Embase, Medline, Cochrane Library, The German Institute of Medical Documentation and Information (DIMDI) and the ISPOR conference websites. Results The search identified 200 literature reviews, covering several dimensions of humanistic burden and documenting many issues. Main findings included the high death rates that may be explained by long-lasting negative health habits, disease- and treatment-related metabolic disorders, and consequent increased frequencies of cardiovascular diseases. Co-existing depression was found to have adverse consequence on the course of schizophrenia progression, morbidity and mortality. Cognitive impairment also adds to the burden of schizophrenia. Social impairment is worsened by underestimated stigmatisation and lack of corresponding awareness within the professional and social spheres. Finally, caregiver burden was found to be considerable. Discussion Humanistic burden among patients with schizophrenia is substantial potentially impacted by co-morbid depressive symptoms, caregiver burden and cognitive impairment. Effects of treatment on humanistic burden in addition to economic burden need to be explored in future trials
Particle-Like Description in Quintessential Cosmology
Assuming equation of state for quintessential matter: , we
analyse dynamical behaviour of the scale factor in FRW cosmologies. It is shown
that its dynamics is formally equivalent to that of a classical particle under
the action of 1D potential . It is shown that Hamiltonian method can be
easily implemented to obtain a classification of all cosmological solutions in
the phase space as well as in the configurational space. Examples taken from
modern cosmology illustrate the effectiveness of the presented approach.
Advantages of representing dynamics as a 1D Hamiltonian flow, in the analysis
of acceleration and horizon problems, are presented. The inverse problem of
reconstructing the Hamiltonian dynamics (i.e. potential function) from the
luminosity distance function for supernovae is also considered.Comment: 35 pages, 26 figures, RevTeX4, some applications of our treatment to
investigation of quintessence models were adde
A nonlocal, covariant generalisation of the NJL model
We solve a nonlocal generalisation of the NJL model in the Hartree
approximation. This model has a separable interaction, as suggested by
instanton models of the QCD vacuum. The choice of form factor in this
interaction is motivated by the confining nature of the vacuum. A conserved
axial current is constructed in the chiral limit of the model and the pion
properties are shown to satisfy the Gell-Mann--Oakes--Renner relation. For
reasonable values of the parameters the model exhibits quark confinement.Comment: 13 pages (RevTeX), MC/TH 94/1
Rotating black hole orbit functionals in the frequency domain
In many astrophysical problems, it is important to understand the behavior of
functions that come from rotating (Kerr) black hole orbits. It can be
particularly useful to work with the frequency domain representation of those
functions, in order to bring out their harmonic dependence upon the fundamental
orbital frequencies of Kerr black holes. Although, as has recently been shown
by W. Schmidt, such a frequency domain representation must exist, the coupled
nature of a black hole orbit's and motions makes it difficult to
construct such a representation in practice. Combining Schmidt's description
with a clever choice of timelike coordinate suggested by Y. Mino, we have
developed a simple procedure that sidesteps this difficulty. One first Fourier
expands all quantities using Mino's time coordinate . In particular,
the observer's time is decomposed with . The frequency domain
description is then built from the -Fourier expansion and the
expansion of . We have found this procedure to be quite simple to implement,
and to be applicable to a wide class of functionals. We test the procedure
using a simple test function, and then apply it in a particularly interesting
case, the Weyl curvature scalar used in black hole perturbation
theory.Comment: 16 pages, 2 figures. Submitted to Phys Rev D. New version gives a
vastly improved algorithm due to Drasco for computing the Fourier transforms.
Drasco has been added as an author. Also fixed some references and
exterminated a small herd of typos; final published versio
Role of Brans-Dicke Theory with or without self-interacting potential in cosmic acceleration
In this work we have studied the possibility of obtaining cosmic acceleration
in Brans-Dicke theory with varying or constant (Brans- Dicke
parameter) and with or without self-interacting potential, the background fluid
being barotropic fluid or Generalized Chaplygin Gas. Here we take the power law
form of the scale factor and the scalar field. We show that accelerated
expansion can also be achieved for high values of for closed Universe.Comment: 12 Latex pages, 20 figures, RevTex styl
Large eddy simulation of a turbulent non-premixed propane-air reacting flame in a cylindrical combustor
Large Eddy Simulation (LES) is applied to investigate the turbulent non-premixed combustion flow, including species concentrations and temperature, in a cylindrical combustor. Gaseous propane (C3H8) is injected through a circular nozzle which is attached at the centre of the combustor inlet. Preheated air with a temperature of 773 K is supplied through the annulus surrounding of this fuel nozzle. In LES a spatial filtering is applied to the governing equations to separate the flow field into large-scale and small-scale eddies. The large-scale eddies which carry most of the turbulent energy are resolved explicitly, while the unresolved small-scale eddies are modelled using the Smagorinsky model with Cs = 0.1 as well as dynamically calibrated Cs. The filtered values of the species mass fraction, temperature and density, which are the functions of the mixture fraction (conserved scalar), are determined by integration over a beta probability density function (β-PDF). The computational results are compared with those of the experimental investigation conducted by Nishida and Mukohara. According to this experiment, the overall equivalence ratio of 0.6, which is calculated from the ratio of the air flow rate supplied to the combustion chamber to that of the stoichiometric reaction, is kept constant so that the turbulent combustion at the fuel nozzle exit starts under the fuel-rich conditions
- …