30,086 research outputs found
Software for web-based tic suppression training [version 2; referees: 3 approved]
Exposure and response prevention (ERP) is a first-line behavior therapy for obsessive-compulsive disorder and Tourette syndrome (TS). However, ERP for tic disorders requires intentional tic suppression, which for some patients is difficult even for brief periods. Additionally, practical access to behavior therapy is difficult for many patients, especially those in rural areas. The authors present a simple, working web platform (TicTrainer) that implements a strategy called reward-enhanced exposure and response prevention (RE–ERP). This strategy sacrifices most expert therapist components of ERP, focusing only on increasing the duration of time for which the user can suppress tics through automated differential reinforcement of tic-free periods (DRO). RE–ERP requires an external tic monitor, such as a parent, during training sessions. The user sees increasing digital rewards for longer and longer periods of successful tic suppression, similar to a video game score. TicTrainer is designed with security in mind, storing no personally identifiable health information, and has features to facilitate research, including optional masked comparison of tics during DRO vs. noncontingent reward conditions. A working instance of TicTrainer is available from https://tictrainer.com
How the credit channel works: differentiating the bank lending channel and the balance sheet channel
The credit channel of monetary policy transmission operates through changes in lending. To examine this channel, we explore how movements in the real federal funds rate affect bank lending. Using data on individual loans from the Survey of Terms of Bank Lending, we are able to differentiate two ways the credit channel can work: by affecting overall bank lending (the bank lending channel) and by affecting the allocation of loans (the balance sheet channel). We find evidence consistent with the operation of both internal credit channels. During periods of tight monetary policy, banks adjust their stock of loans by reducing the maturity of loan originations and they reallocate their short-term loan supply from small firms to large firms. These results are stronger for large banks than for small banks.Monetary policy ; Bank loans
Gas Gain Measurements from a Negative Ion TPC X-ray Polarimeter
Gas-based time projection chambers (TPCs) have been shown to be highly
sensitive X-ray polarimeters having excellent quantum efficiency while at the
same time achieving large modulation factors. To observe polarization of the
prompt X-ray emission of a Gamma-ray burst (GRB), a large area detector is
needed. Diffusion of the electron cloud in a standard TPC could be prohibitive
to measuring good modulation when the drift distance is large. Therefore, we
propose using a negative ion TPC (NITPC) with Nitromethane (CH3NO2) as the
electron capture agent. The diffusion of negative ions is reduced over that of
electrons due to the thermal coupling of the negative ions to the surrounding
gas. This allows for larger area detectors as the drift distance can be
increased without degrading polarimeter modulation. Negative ions also travel
~200 times slower than electrons, allowing the readout electronics to operate
slower, resulting in a reduction of instrument power. To optimize the NITPC
design, we have measured gas gain with SciEnergy gas electron multipliers
(GEMs) in single and double GEM configurations. Each setup was tested with
different gas combinations, concentrations and pressures: P10 700 Torr, Ne+CO2
700 Torr at varying concentrations of CO2 and Ne+CO2+CH3NO2 700 Torr. We report
gain as a function of total voltage, measured from top to bottom of the GEM
stack, and as a function of drift field strength for the gas concentrations
listed above. Examples of photoelectron tracks at 5.9 keV are also presented.Comment: 6 pages, 6 figures, accepted for publication in IEEE Trans Nucl Sc
Some contemporary issues affecting the South African auditor : inaugural address delivered at Rhodes University
Inaugural address delivered at Rhodes University.Rhodes University Libraries (Digitisation
A benign, low Z electron capture agent for negative ion TPCs
We have identified nitromethane (CHNO) as an effective electron
capture agent for negative ion TPCs (NITPCs).
We present drift velocity and longitudinal diffusion measurements for
negative ion gas mixtures using nitromethane as the capture agent.
Not only is nitromethane substantially more benign than the only other
identified capture agent, CS, but its low atomic number will enable the use
of the NITPC as a photoelectric X{}-ray polarimeter in the 1{}-10 keV band
Classifying the secondary component of the binary star W Aquilae
AIMS: The object W Aql is an asymptotic giant branch (AGB) star with a faint
companion. By determining more carefully the properties of the companion, we
hope to better constrain the properties of the AGB star. METHODS: We present
new spectral observations of the binary star W Aql at minimum and maximum
brightness and new photometric observations of W Aql at minimum brightness.
RESULTS: The composite spectrum near minimum light is predominantly from the
companion at wavelengths < 6000 . This spectrum can be
classified as F8 to G0, and the brightness of the companion is that of a dwarf
star. Therefore, it can be concluded that the companion is a main sequence
star. From this, we are able to constrain the mass of the AGB component to 1.04
- 3 and the mass of the W Aql system to 2.1 - 4.1 . Our
photometric results are broadly consistent with this classification and suggest
that the main sequence component suffers from approximately 2 mag of extinction
in the V band primarily due to the dust surrounding the AGB component.Comment: 5 pages, 1 figure, research not
Sulphur molecules in the circumstellar envelopes of M-type AGB stars
The sulphur compounds SO and SO have not been widely studied in the
circumstellar envelopes of asymptotic giant branch (AGB) stars. By presenting
and modelling a large number of SO and SO lines in the low mass-loss rate
M-type AGB star R Dor, and modelling the available lines of those molecules in
a further four M-type AGB stars, we aim to determine their circumstellar
abundances and distributions. We use a detailed radiative transfer analysis
based on the accelerated lambda iteration method to model circumstellar SO and
SO line emission and molecular data files for both SO and SO that are
more extensive than those previously available. Using 17 SO lines and 98 SO2
lines to constrain our models for R Dor, we find an SO abundance of
6.7x10 and an SO abundance of 5x10 with both species having
high abundances close to the star. We also modelled SO and found an
abundance of 3.1x10, giving an SO/SO ratio of 21.6. We
derive similar results for the circumstellar SO and SO abundances and their
distributions for the low mass-loss rate object W Hya. For these stars, the
circumstellar SO and SO abundances are much higher than predicted by
chemical models and these two species may account for all available sulphur.
For the higher mass-loss rate stars, we find shell-like SO distributions with
peak abundances that decrease and peak abundance radii that increase with
increasing mass-loss rate. The positions of the peak SO abundance agree very
well with the photodissociation radii of HO. We find evidence that SO is
most likely through the photodissociation of HO and the subsequent reaction
between S and OH. The S-bearing parent molecule appears not to be HS. The
SO models suggest an origin close to the star for this species, also
disagreeing with current chemical models.Comment: 25 page
Float-polishing process and analysis of float-polished quartz
A fluid-mechanical model is developed for the float-polishing process. In this model laminar flow between the sample and the lap results in pressure gradients at the grooves that support the sample on a fluid layer. The laminar fluid motion also produces supersmooth, damage-free surfaces. Quartz substrates for applications in high-stress environments were float polished, and their surfaces were analyzed by optical scatterometry, photoacoustic spectroscopy, and atomic force microscopy. The removal of 100 µm of material by a lapping-polishing process, with final float polishing, left low levels of subsurface damage, with a surface roughness of approximately 0.2-nm rms
X-ray polarimetry with an active-matrix pixel proportional counter
We report the first results from an X-ray polarimeter with a micropattern gas
proportional counter using an amorphous silicon active matrix readout. With
100% polarized X-rays at 4.5 keV, we obtain a modulation factor of 0.33 +/-
0.03, confirming previous reports of the high polarization sensitivity of a
finely segmented pixel proportional counter. The detector described here has a
geometry suitable for the focal plane of an astronomical X-ray telescope.
Amorphous silicon readout technology will enable additional extensions and
improvements.Comment: 4 pages, 4 figures, 1 tabl
TicTimer Web: Software for measuring tic suppression remotely
Woods and Himle developed a standardized tic suppression paradigm (TSP) for the experimental setting, to quantify the effects of intentional tic suppression in Tourette syndrome. We previously provided a computer program to facilitate recording tic occurrence and to automate reward delivery during the several experimental conditions of the TSP. The present article describes a web-based program that performs the same functions. Implementing this program on the web allows research sessions to be performed remotely, in tandem with a video calling program. Relevant data for each session, such as the timing of tics and dispensed rewards, are stored in plain text files for later analysis. Expected applications include research on Tourette syndrome and related disorders
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