17,263 research outputs found
Image readout device with electronically variable spatial resolution
An invention relating to the use of a standing acoustic wave charge storage device as an image readout device is described. A frequency f sub 1 was applied to the storage transfer device to create a traveling electric field in the device in one direction along a straight line. A second frequency f sub 2 was applied to the charge transfer device to create a traveling electric field opposite to the first traveling electric field. A standing wave was created. When an image was focused on the charge transfer device, light was stored in the wells of the standing wave. When the frequency f sub 2 is removed from the device, the standing wave tends to break up and the charges stored move to an electrode connected to an output terminal and to a utilization device where the received charges represent the image on the surface of the charge transfer device along a projection of said straight line
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.
A new Monte Carlo code for star cluster simulations: II. Central black hole and stellar collisions
We have recently written a new code to simulate the long term evolution of
spherical clusters of stars. It is based on the pioneering Monte Carlo scheme
proposed by Henon in the 70's. Our code has been devised in the specific goal
to treat dense galactic nuclei. After having described how we treat relaxation
in a first paper, we go on and include further physical ingredients that are
mostly pertinent to galactic nuclei, namely the presence of a central (growing)
black hole (BH) and collisions between MS stars. Stars that venture too close
to the BH are destroyed by the tidal field. This process is a channel to feed
the BH and a way to produce accretion flares. Collisions between stars have
often been proposed as another mechanism to drive stellar matter into the
central BH. To get the best handle on the role of this process in galactic
nuclei, we include it with unpreceded realism through the use of a set of more
than 10000 collision simulations carried out with a SPH (Smoothed Particle
Hydrodynamics) code. Stellar evolution has also been introduced in a simple
way, similar to what has been done in previous dynamical simulations of
galactic nuclei. To ensure that this physics is correctly simulated, we
realized a variety of tests whose results are reported here. This unique code,
featuring most important physical processes, allows million particle
simulations, spanning a Hubble time, in a few CPU days on standard personal
computers and provides a wealth of data only rivalized by N-body simulations.Comment: 32 pages, 19 figures. Slightly shortened and clarified following
referee's suggestions. Accepted for publication in A&A. Version with high
quality figures available at
http://obswww.unige.ch/~freitag/papers/article_MC2.ps.g
Temporal Correlation of Hard X-rays and Meter/Decimeter Radio Structures in Solar Flares
We investigate the relative timing between hard X-ray (HXR) peaks and
structures in metric and decimetric radio emissions of solar flares using data
from the RHESSI and Phoenix-2 instruments. The radio events under consideration
are predominantly classified as type III bursts, decimetric pulsations and
patches. The RHESSI data are demodulated using special techniques appropriate
for a Phoenix-2 temporal resolution of 0.1s. The absolute timing accuracy of
the two instruments is found to be about 170 ms, and much better on the
average. It is found that type III radio groups often coincide with enhanced
HXR emission, but only a relatively small fraction ( 20%) of the groups
show close correlation on time scales 1s. If structures correlate, the HXRs
precede the type III emissions in a majority of cases, and by 0.690.19 s
on the average. Reversed drift type III bursts are also delayed, but
high-frequency and harmonic emission is retarded less. The decimetric
pulsations and patches (DCIM) have a larger scatter of delays, but do not have
a statistically significant sign or an average different from zero. The time
delay does not show a center-to-limb variation excluding simple propagation
effects. The delay by scattering near the source region is suggested to be the
most efficient process on the average for delaying type III radio emission
Spin transport in a one-dimensional anisotropic Heisenberg model
We analytically and numerically study spin transport in a one-dimensional
Heisenberg model in linear-response regime at infinite temperature. It is shown
that as the anisotropy parameter Delta is varied spin transport changes from
ballistic for Delta<1 to anomalous at the isotropic point Delta=1, to diffusive
for finite Delta>1, ending up as a perfect isolator in the Ising limit of
infinite Delta. Using perturbation theory for large Delta a quantitative
prediction is made for the dependence of diffusion constant on Delta.Comment: 5 pages, 4 figures; v2.: few comments added and typos corrected;
published versio
Formation of bi-lobed shapes by sub-catastrophic collisions: A late origin of comet 67P/C-G's structure
The origin of the particular shape of a small body like comet
67P/Churyumov-Gerasimenko (67P/C-G) is a topic of active research. How and when
it acquired its peculiar characteristics has distinct implications on the
origin of the solar system and its dynamics. We investigate how shapes like the
one of comet 67P/C-G can result from a new type of low-energy, sub-catastrophic
impacts involving elongated, rotating bodies. We focus on parameters
potentially leading to bi-lobed structures. We also estimate the probability
for such structures to survive subsequent impacts. We use a smooth particle
hydrodynamics (SPH) shock physics code to model the impacts, the subsequent
reaccumulation of material and the reconfiguration into a stable final shape.
The energy increase as well as the degree of compaction of the resulting bodies
are tracked in the simulations. Our modelling results suggest that the
formation of bi-lobed structures like 67P/C-G is a natural outcome of the low
energy, sub-catastrophic collisions considered here. Sub-catastrophic impacts
have the potential to alter the shape of a small body significantly, without
leading to major heating or compaction. The currently observed shapes of
cometary nuclei, such as 67P/C-G, maybe a result of such a last major shape
forming impact.Comment: Astronomy & Astrophysics, accepted pending minor revision
Formation and composition of planets around very low mass stars
The recent detection of planets around very low mass stars raises the
question of the formation, composition and potential habitability of these
objects. We use planetary system formation models to infer the properties, in
particular their radius distribution and water content, of planets that may
form around stars ten times less massive than the Sun. Our planetary system
formation and composition models take into account the structure and evolution
of the protoplanetary disk, the planetary mass growth by accretion of solids
and gas, as well as planet-planet, planet-star and planet-disk interactions. We
show that planets can form at small orbital period in orbit about low mass
stars. We show that the radius of the planets is peaked at about 1 rearth and
that they are, in general, volatile rich especially if proto-planetary discs
orbiting this type of stars are long-lived. Close-in planets orbiting low-mass
stars similar in terms of mass and radius to the ones recently detected can be
formed within the framework of the core accretion paradigm as modeled here. The
properties of protoplanetary disks, and their correlation with the stellar
type, are key to understand their composition.Comment: to appear in Astronomy and Astrophysics Letter
Catastrophic disruptions revisited
We use a smooth particle hydrodynamics method (SPH) to simulate colliding
rocky and icy bodies from cm-scale to hundreds of km in diameter, in an effort
to define self-consistently the threshold for catastrophic disruption. Unlike
previous efforts, this analysis incorporates the combined effects of material
strength (using a brittle fragmentation model) and self-gravitation, thereby
providing results in the ``strength regime'' and the ``gravity regime'', and in
between. In each case, the structural properties of the largest remnant are
examined.Comment: To appear in Icaru
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