5,296 research outputs found
Therapeutic effects of music therapy on anxiety and quality of life for chronically ill adults with mental illness
Mental Illness impacts many individuals, families and communities. Treatments for chronically mentally ill individuals include a variety of medications and behavioral therapies. Alternative therapies can also help reduce anxiety and improve social behavior. Music therapy has been identified as one method to reduce anxiety, resulting in an increased quality of life. The purpose of this study is to examine the impact of music therapy on social anxiety and quality of life for individuals who are chronically mentally ill. This is a replication of Grocke, Bloch and Castle’s (2009) study. The study is based on Group Music Therapy (Bloch & Crouch, 1985). The anticipated sample will include 500 outpatients being treated in a local mental health facility in MD. The WHOQOLBREF Quality of Life Scale, the Social Interaction Anxiety Scale and the Brief Symptom Inventory will be used to collect data. Semi-structured interviews will also be conducted with focus groups. Findings will provide insight about the impact of music therapy as an alternative treatment to reduce anxiety and improve quality of life for chronically ill individuals.School of NursingThesis (M.S.
ARISTOTELES: A European approach for an Earth gravity field recovery mission
Under contract of the European Space Agency a system study for a spaceborne gravity field recovery mission was performed, covering as a secondary mission objective geodetic point positioning in the cm range as well. It was demonstrated that under the given programmatic constraints including dual launch and a very tight development schedule, a six months gravity field mission in a 200 km near polar, dawn-dusk orbit is adequate to determine gravity anomalies to better than 5 mgal with a spatial resolution of 100 x 100 km half wavelength. This will enable scientists to determine improved spherical harmonic coefficients of the Earth gravity field equation to the order and degree of 180 or better
Theoretical and material studies on thin-film electroluminescent devices
The effect of surface nucleation processes on the quality of ZnS layers grown on (001) GaAs substrates by molecular beam epitaxy is reported. Reflection high energy electron diffraction indicated that nucleation at high temperatures produced more planar surfaces than nucleation at low temperatures, but the crystalline quality as accessed by x ray double crystal diffractometry is relatively independent of nucleation temperature. A critical factor in layer quality was the initial roughness of the GaAs surfaces
Formation and long-term evolution of 3D vortices in protoplanetary discs
In the context of planet formation, anticyclonic vortices have recently
received lots of attention for the role they can play in planetesimals
formation. Radial migration of intermediate size solids toward the central star
may prevent their growth to larger solid grains. On the other hand, vortices
can trap the dust and accelerate this growth, counteracting fast radial
transport. Multiple effects have been shown to affect this scenario, such as
vortex migration or decay. The aim of this paper is to study the formation of
vortices by the Rossby wave instability and their long term evolution in a full
three dimensional protoplanetary disc. We use a robust numerical scheme
combined with adaptive mesh refinement in cylindrical coordinates, allowing to
affordably compute long term 3D evolutions. We consider a full disc stratified
both radially and vertically that is prone to formation of vortices by the
Rossby wave instability. We show that the 3D Rossby vortices grow and survive
over hundreds of years without migration. The localized overdensity which
initiated the instability and vortex formation survives the growth of the
Rossby wave instability for very long times. When the vortices are no longer
sustained by the Rossby wave instability, their shape changes toward more
elliptical vortices. This allows them to survive shear-driven destruction, but
they may be prone to elliptical instability and slow decay. When the conditions
for growing Rossby wave-related instabilities are maintained in the disc,
large-scale vortices can survive over very long timescales and may be able to
concentrate solids.Comment: Accepted for publication in A&
Device and method for frictionally testing materials for ignitability
Test apparatus for determining ignition characteristics of various metal in oxidizer environments simulating operating conditions for materials is invented. The test apparatus has a chamber through which the oxidizing agent flows, and means for mounting a stationary test sample therein, a powered, rotating shaft in the chamber rigidly mounts a second test sample. The shaft is axially movable to bring the samples into frictional engagement and heated to the ignition point. Instrumentation connected to the apparatus provides for observation of temperatures, pressures, loads on and speeds of the rotating shaft, and torques whereby components of stressed oxygen systems can be selected which will avoid accidental fires under working conditions
Collisions of inhomogeneous pre-planetesimals
In the framework of the coagulation scenario, kilometre-sized planetesimals
form by subsequent collisions of pre-planetesimals of sizes from centimetre to
hundreds of metres. Pre-planetesimals are fluffy, porous dust aggregates, which
are inhomogeneous owing to their collisional history. Planetesimal growth can
be prevented by catastrophic disruption in pre-planetesimal collisions above
the destruction velocity threshold. We develop an inhomogeneity model based on
the density distribution of dust aggregates, which is assumed to be a Gaussian
distribution with a well-defined standard deviation. As a second input
parameter, we consider the typical size of an inhomogeneous clump. These input
parameters are easily accessible by laboratory experiments. For the simulation
of the dust aggregates, we utilise a smoothed particle hydrodynamics (SPH) code
with extensions for modelling porous solid bodies. The porosity model was
previously calibrated for the simulation of silica dust, which commonly serves
as an analogue for pre-planetesimal material. The inhomogeneity is imposed as
an initial condition on the SPH particle distribution. We carry out collisions
of centimetre-sized dust aggregates of intermediate porosity. We vary the
standard deviation of the inhomogeneous distribution at fixed typical clump
size. The collision outcome is categorised according to the four-population
model. We show that inhomogeneous pre-planetesimals are more prone to
destruction than homogeneous aggregates. Even slight inhomogeneities can lower
the threshold for catastrophic disruption. For a fixed collision velocity, the
sizes of the fragments decrease with increasing inhomogeneity.
Pre-planetesimals with an active collisional history tend to be weaker. This is
a possible obstacle to collisional growth and needs to be taken into account in
future studies of the coagulation scenario.Comment: 12 pages, 9 figures, 4 table
How primordial is the structure of comet 67P/C-G? Combined collisional and dynamical models suggest a late formation
There is an active debate about whether the properties of comets as observed
today are primordial or, alternatively, if they are a result of collisional
evolution or other processes. We investigate the effects of collisions on a
comet with a structure like 67P/C-G. We develop scaling laws for the critical
specific impact energies required for a significant shape alteration. These are
then used in simulations of the combined dynamical and collisional evolution of
comets in order to study the survival probability of a primordially formed
object with a shape like 67P/C-G. The effects of impacts on comet 67P/C-G are
studied using a SPH shock physics code. The resulting critical specific impact
energy defines a minimal projectile size which is used to compute the number of
shape-changing collisions in a set of dynamical simulations. These simulations
follow the dispersion of the trans-Neptunian disk during the giant planet
instability, the formation of a scattered disk, and produce 87 objects that
penetrate into the inner solar system with orbits consistent with the observed
JFC population. The collisional evolution before the giant planet instability
is not considered here. Hence, our study is conservative in its estimation of
the number of collisions. We find that in any scenario considered here, comet
67P/C-G would have experienced a significant number of shape-changing
collisions, if it formed primordially. This is also the case for generic
bi-lobe shapes. Our study also shows that impact heating is very localized and
that collisionally processed bodies can still have a high porosity. Our study
indicates that the observed bi-lobe structure of comet 67P/C-G may not be
primordial, but might have originated in a rather recent event, possibly within
the last 1 Gy. This may be the case for any kilometer-sized two-component
cometary nuclei.Comment: Astronomy & Astrophysics, accepted pending minor revision
Projection operator approach to spin diffusion in the anisotropic Heisenberg chain at high temperatures
We investigate spin transport in the anisotropic Heisenberg chain in the
limit of high temperatures ({\beta} \to 0). We particularly focus on diffusion
and the quantitative evaluation of diffusion constants from current
autocorrelations as a function of the anisotropy parameter {\Delta} and the
spin quantum number s. Our approach is essentially based on an application of
the time-convolutionless (TCL) projection operator technique. Within this
perturbative approach the projection onto the current yields the decay of
autocorrelations to lowest order of {\Delta}. The resulting diffusion constants
scale as 1/{\Delta}^2 in the Markovian regime {\Delta}<<1 (s=1/2) and as
1/{\Delta} in the highly non-Markovian regime above {\Delta} \sim 1 (arbitrary
s). In the latter regime the dependence on s appears approximately as an
overall scaling factor \sqrt{s(s+1)} only. These results are in remarkably good
agreement with diffusion constants for {\Delta}>1 which are obtained directly
from the exact diagonalization of autocorrelations or have been obtained from
non-equilibrium bath scenarios.Comment: 4 pages, 3 figure
Reconnection in Marginally Collisionless Accretion Disk Coronae
We point out that a conventional construction placed upon observations of
accreting black holes, in which their nonthermal X-ray spectra are produced by
inverse comptonization in a coronal plasma, suggests that the plasma is
marginally collisionless. Recent developments in plasma physics indicate that
fast reconnection takes place only in collisionless plasmas. As has recently
been suggested for the Sun's corona, such marginal states may result from a
combination of energy balance and the requirements of fast magnetic
reconnection.Comment: Revised in response to referee. Accepted ApJ. 11 pp., no figures.
Uses aastex 5.0
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