91,648 research outputs found
A pilot evaluation of positive behavioural support workshops for families of adults with intellectual disabilities who present challenging behaviour: 'It should have been offered years ago'
Background: Positive behavioural support (PBS) workshops were designed for families supporting their adult son or daughter with an intellectual disability engaging in challenging behaviours. This was in recognition of the impact of their challenging behaviour, in particular the level of stress carers often experience and positive reports from other studies incorporating multi-family learning.
Method and materials: Two sets of pilot workshops were completed, incorporating modules in PBS and physical interventions. Workshops included presentations and self-directed/group learning tasks, recorded in a specifically designed workbook.
Results: Quantitative data was analysed using non-parametric tests. Positive results were found for changes in various areas including self-reported stress levels. Positive trends were also found in pre and post application of the Aberrant Behaviour Checklist (Aman and Singh, 1994).
Conclusions: This study showed very encouraging results in regard to the impact of this model of training for the carers involved. Further research is required to assess any longer term effects, and to explore the impact on larger numbers of participants
Recovering Solar Toroidal Field Dynamics From Sunspot Location Patterns
We analyze both Kitt Peak magnetogram data and MDI continuum intensity
sunspot data to search for the following solar toroidal band properties: width
in latitude and the existence of a tipping instability (longitudinal m=1 mode)
for any time during the solar cycle. To determine the extent which we can
recover the toroidal field dynamics, we forward model artificially generated
sunspot distributions from subsurface toroidal fields we assigned certain
properties. We analyzed two sunspot distribution parameters using MDI and model
data: the average latitudinal separation of sunspot pairs as a function of
longitudinal separation, and the number of sunspot pairs creating a given angle
with respect to the E-W direction. A toroidal band of 10 degrees width with a
constant tipping of 5 degrees best fits MDI data early in the solar cycle. A
toroidal band of 20 degrees width with a tipping amplitude decreasing in time
from 5 to 0 degrees best fits MDI data late in the solar cycle. Model data
generated by untipped toroidal bands cannot fit MDI high latitude data and can
fit only one parameter at low latitudes. Tipped toroidal bands satisfy chi
squared criteria at both high and low latitudes. We conclude this is evidence
to reject the null hypothesis - that toroidal bands in the solar tachocline do
not experience a tipping instability - in favor of the hypothesis that the
toroidal band experiences an m=1 tipping instability. Our finding that the band
widens from ~10 degrees early in the solar cycle to ~20 degrees late in the
solar cycle may be explained in theory by magnetic drag spreading the toroidal
band due to altered flow along the tipped field lines.Comment: This paper is accepted to Astrophysical Journal, September 2005 issu
On groups with a class-preserving outer automorphism
In 1911, Burnside asked whether or not there exist groups that have an outer
automorphism which preserves conjugacy classes. Two years later he answered his
own question by constructing a family of such groups. Using the small group
library in MAGMA we determine all of the groups of order n < 512 that possess
such an automorphism. Our investigations led to the discovery of four new
infinite families of such groups, all of which are 2-groups of coclass 4
Nonstationary westward translation of nonlinear frontal warm-core eddies
For the first time, an analytical theory and a very high-resolution, frontal numerical model, both based on the unsteady, nonlinear, reduced-gravity shallow water equations on a beta plane, have been used to investigate aspects of the migration of homogeneous surface, frontal warm-core eddies on a beta plane. Under the assumption that, initially, such vortices are surface circular anticyclones of paraboloidal shape and having both radial and azimuthal velocities that are linearly dependent on the radial coordinate (i.e., circular pulsons of the first order), approximate analytical expressions are found that describe the nonstationary trajectories of their centers of mass for an initial stage as well as for a mature stage of their westward migration. In particular, near-inertial oscillations are evident in the initial migration stage, whose amplitude linearly increases with time, as a result of the unbalanced vortex initial state on a beta plane. Such an initial amplification of the vortex oscillations is actually found in the first stage of the evolution of warm-core frontal eddies simulated numerically by means of a frontal numerical model initialized using the shape and velocity fields of circular pulsons of the first order. In the numerical simulations, this stage is followed by an adjusted, complex nonstationary state characterized by a noticeable asymmetry in the meridional component of the vortex's horizontal pressure gradient, which develops to compensate for the variations of the Coriolis parameter with latitude. Accordingly, the location of the simulated vortex's maximum depth is always found poleward of the location of the simulated vortex's center of mass. Moreover, during the adjusted stage, near-inertial oscillations emerge that largely deviate from the exactly inertial ones characterizing analytical circular pulsons: a superinertial and a subinertial oscillation in fact appear, and their frequency difference is found to be an increasing function of latitude. A comparison between vortex westward drifts simulated numerically at different latitudes for different vortex radii and pulsation strengths and the corresponding drifts obtained using existing formulas shows that, initially, the simulated vortex drifts correspond to the fastest predicted ones in many realistic cases. As time elapses, however, the development of a beta-adjusted vortex structure, together with the effects of numerical dissipation, tend to slow down the simulated vortex drift
Nonlinear transverse oscillations of a geostrophic front
A planar problem of nonlinear transverse oscillations of the surface (warm) front of a finite width is considered within the framework of a reduced-gravity model of the ocean. The source of oscillations is the departure of the front from its geostrophic equilibrium. When the current velocity is linear in the horizontal coordinate and the front's depth is quadratic in this coordinate, the problem is reduced to a system of four ordinary differential equations in time. As a result, the solution is obtained in a weakly nonlinear approximation and strongly nonlinear oscillations of the front are studied by numerically solving this system of equations by the Runge-Kutta method. The front's oscillations are always superinertial. Nonlinearity can lead to a decrease or increase in the oscillation frequency in comparison with the linear case. The oscillations are most intense when the current velocity is disturbed in the direction of the front's axis. A weakly nonlinear solution of the second order describes the oscillations very accurately even for initial velocity disturbances reaching 50% of its geostrophic value. An increase in the background-current shear leads to the damping of oscillations of the front's boundary. The amplitude of oscillations of the current velocity increases as the intensity of disturbances increases, and it is relatively small if background-current shears are small or large
Observable Dependent Quasi-Equilibrium in Slow Dynamics
We present examples demonstrating that quasi-equilibrium
fluctuation-dissipation behavior at short time differences is not a generic
feature of systems with slow non-equilibrium dynamics. We analyze in detail the
non-equilibrium fluctuation-dissipation ratio X(t,tw) associated with a
defect-pair observable in the Glauber-Ising spin chain. It turns out that throughout the short-time regime and in particular X(tw,tw) = 3/4 for
. The analysis is extended to observables detecting defects at a
finite distance from each other, where similar violations of quasi-equilibrium
behaviour are found. We discuss our results in the context of metastable
states, which suggests that a violation of short-time quasi-equilibrium
behavior could occur in general glassy systems for appropriately chosen
observables.Comment: 17 pages, 5 figures; substantially improved version of
cond-mat/040571
Kink-Antikink Unbinding Transition in the Two Dimensional Fully Frustrated XY Model
We carry out the first numerical simulations to directly confirm the
existence of a kink-antikink unbinding transition, T_w, along Ising-like domain
walls in the two dimensional fully frustrated XY model. We comment on the
possible implications of kink-antikink unbinding for the bulk phase transitions
of the model.Comment: 8 pages, 10 figures - expanded version of original submission as
accepted by Phys. Rev. B. Some correction to the analysis lead to an increase
in the value of the kink unbinding transition temperatur
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