468 research outputs found
Depressive disorder in children and adolescents: Dysthymic disorder and the use of self-rating scales in assessment
The authors describe a pilot study on depressed children and adolescents, where the DSM-III diagnosis on clinical interviews is compared to the results from two self-rating scales on 35 children and adolescents referred to the researchers. These 35 subjects were seen as depressed by their primary helpers. The value of the self-rating scales is mentioned and the usefulness of the category “dysthymic disorder” is commented upon
Cognitive bias and depression in psychiatrically disturbed children and adolescents
Developed a cognitive bias questionnaire for children (CBQC) to examine the relation between cognitive distortion and depression in 39 psychiatrically disturbed 8–16 yr olds. Results indicate that the Depressed–Distorted scale from the CBQC was significantly correlated with Ss\u27 psychiatric and self-reported ratings of depression and could significantly discriminate affective from nonaffective disorders
Recovery of Large Angular Scale CMB Polarization for Instruments Employing Variable-delay Polarization Modulators
Variable-delay Polarization Modulators (VPMs) are currently being implemented
in experiments designed to measure the polarization of the cosmic microwave
background on large angular scales because of their capability for providing
rapid, front-end polarization modulation and control over systematic errors.
Despite the advantages provided by the VPM, it is important to identify and
mitigate any time-varying effects that leak into the synchronously modulated
component of the signal. In this paper, the effect of emission from a K
VPM on the system performance is considered and addressed. Though instrument
design can greatly reduce the influence of modulated VPM emission, some
residual modulated signal is expected. VPM emission is treated in the presence
of rotational misalignments and temperature variation. Simulations of
time-ordered data are used to evaluate the effect of these residual errors on
the power spectrum. The analysis and modeling in this paper guides
experimentalists on the critical aspects of observations using VPMs as
front-end modulators. By implementing the characterizations and controls as
described, front-end VPM modulation can be very powerful for mitigating
noise in large angular scale polarimetric surveys. None of the systematic
errors studied fundamentally limit the detection and characterization of
B-modes on large scales for a tensor-to-scalar ratio of . Indeed,
is achievable with commensurately improved characterizations and
controls.Comment: 13 pages, 13 figures, 1 table, matches published versio
Low-resolution spectroscopy of the Sunyaev-Zel'dovich effect and estimates of cluster parameters
The Sunyaev-Zel'dovich (SZ) effect is a powerful tool for studying clusters
of galaxies and cosmology. Large mm-wave telescopes are now routinely detecting
and mapping the SZ effect in a number of clusters, measure their comptonisation
parameter and use them as probes of the large-scale structure and evolution of
the universe. We show that estimates of the physical parameters of clusters
(optical depth, plasma temperature, peculiar velocity, non-thermal components
etc.) obtained from ground-based multi-band SZ photometry can be significantly
biased, owing to the reduced frequency coverage, to the degeneracy between the
parameters and to the presence of a number of independent components larger
than the number of frequencies measured. We demonstrate that low-resolution
spectroscopic measurements of the SZ effect that also cover frequencies
GHz are effective in removing the degeneracy. We used accurate simulations of
observations with lines-of-sight through clusters of galaxies with different
experimental configurations (4-band photometers, 6-band photometer, multi-range
differential spectrometer, full coverage spectrometers) and different
intracluster plasma stratifications. We find that measurements carried out with
ground-based few-band photometers are biased towards high electron temperatures
and low optical depths, and require coverage of high frequency and/or
independent complementary observations to produce unbiased information; a
differential spectrometer that covers 4 bands with a resolution of $\sim 6 \
GHz$ eliminates most if not all bias; full-range differential spectrometers are
the ultimate resource that allows a full recovery of all parameters.Comment: in pres
The Atacama Cosmology Telescope: CO(J = 3 - 2) mapping and lens modeling of an ACT-selected dusty star-forming galaxy
We report Northern Extended Millimeter Array (NOEMA) CO()
observations of the dusty star-forming galaxy ACT-S\,J020941+001557 at , which was detected as an unresolved source in the Atacama Cosmology
Telescope (ACT) equatorial survey. Our spatially resolved spectral line data
support the derivation of a gravitational lens model from 37 independent
velocity channel maps using a pixel-based algorithm, from which we infer a
velocity-dependent magnification factor with a
luminosity-weighted mean \left\approx 13. The resulting
source-plane reconstruction is consistent with a rotating disk, although other
scenarios cannot be ruled out by our data. After correction for lensing, we
derive a line luminosity , a cold gas mass , a dynamical mass , and a gas mass
fraction . The line brightness
temperature ratio of relative to a Green Bank Telescope
CO() detection may be elevated by a combination of external heating of
molecular clouds, differential lensing, and/or pointing errors.Comment: 8 pages, 5 figures, accepted to Ap
Complex impedance measurements of calorimeters and bolometers: correction for stray impedances
Impedance measurements provide a useful probe of the physics of bolometers
and calorimeters. We describe a method for measuring the complex impedance of
these devices. In previous work, stray impedances and readout electronics of
the measurement apparatus have resulted in artifacts in the impedance data. The
new technique allows experimenters to find an independent Thevenin or Norton
equivalent circuit for each frequency. This method allows experimenters to
easily isolate the device impedance from the effects of parasitic impedances
and frequency dependent gains in amplifiers.Comment: 5 pages, 6 figure
Multiwavelength characterisation of an ACT-selected, lensed dusty star-forming galaxy at z=2.64
We present \ci\,(2--1) and multi-transition CO observations of a dusty
star-forming galaxy, ACT\,J2029+0120, which we spectroscopically confirm to lie
at \,=\,2.64. We detect CO(3--2), CO(5--4), CO(7--6), CO(8--7), and
\ci\,(2--1) at high significance, tentatively detect HCO(4--3), and place
strong upper limits on the integrated strength of dense gas tracers (HCN(4--3)
and CS(7--6)). Multi-transition CO observations and dense gas tracers can
provide valuable constraints on the molecular gas content and excitation
conditions in high-redshift galaxies. We therefore use this unique data set to
construct a CO spectral line energy distribution (SLED) of the source, which is
most consistent with that of a ULIRG/Seyfert or QSO host object in the taxonomy
of the \textit{Herschel} Comprehensive ULIRG Emission Survey. We employ RADEX
models to fit the peak of the CO SLED, inferring a temperature of T117 K
and cm, most consistent with a ULIRG/QSO object
and the presence of high density tracers. We also find that the velocity width
of the \ci\ line is potentially larger than seen in all CO transitions for this
object, and that the ratio is also larger
than seen in other lensed and unlensed submillimeter galaxies and QSO hosts; if
confirmed, this anomaly could be an effect of differential lensing of a shocked
molecular outflow.Comment: Accepted for publication in Ap
The Atacama Cosmology Telescope: Physical Properties of Sunyaev-Zel'dovich Effect Clusters on the Celestial Equator
We present the optical and X-ray properties of 68 galaxy clusters selected
via the Sunyaev-Zel'dovich Effect at 148 GHz by the Atacama Cosmology Telescope
(ACT). Our sample, from an area of 504 square degrees centered on the celestial
equator, is divided into two regions. The main region uses 270 square degrees
of the ACT survey that overlaps with the co-added ugriz imaging from the Sloan
Digital Sky Survey (SDSS) over Stripe 82 plus additional near-infrared pointed
observations with the Apache Point Observatory 3.5-meter telescope. We confirm
a total of 49 clusters to z~1.3, of which 22 (all at z>0.55) are new
discoveries. For the second region the regular-depth SDSS imaging allows us to
confirm 19 more clusters up to z~0.7, of which 10 systems are new. We present
the optical richness, photometric redshifts, and separation between the SZ
position and the brightest cluster galaxy (BCG). We find no significant offset
between the cluster SZ centroid and BCG location and a weak correlation between
optical richness and SZ-derived mass. We also present X-ray fluxes and
luminosities from the ROSAT All Sky Survey which confirm that this is a massive
sample. One of the newly discovered clusters, ACT-CL J0044.4+0113 at z=1.1
(photometric), has an integrated XMM-Newton X-ray temperature of kT_x=7.9+/-1.0
keV and combined mass of M_200a=8.2(-2.5,+3.3)x10^14 M_sun/h70 placing it among
the most massive and X-ray-hot clusters known at redshifts beyond z=1. We also
highlight the optically-rich cluster ACT-CL J2327.4-0204 (RCS2 2327) at z=0.705
(spectroscopic) as the most significant detection of the whole equatorial
sample with a Chandra-derived mass of M_200a=1.9(-0.4,+0.6)x10^15 M_sun/h70,
comparable to some of the most massive known clusters like "El Gordo" and the
Bullet Cluster.Comment: 18 pages, 12 figures. Accepted to the Astrophysical Journal. New
version includes minor changes in the accepted pape
On the modelling of the excesses of galaxy clusters over high-mass thresholds
In this work we present for the first time an application of the Pareto
approach to the modelling of the excesses of galaxy clusters over high-mass
thresholds. The distribution of those excesses can be described by the
generalized Pareto distribution (GPD), which is closely related to the
generalized extreme value (GEV) distribution. After introducing the formalism,
we study the impact of different thresholds and redshift ranges on the
distributions, as well as the influence of the survey area on the mean excess
above a given mass threshold. We also show that both the GPD and the GEV
approach lead to identical results for rare, thus high-mass and high-redshift,
clusters. As an example, we apply the Pareto approach to ACT-CL J0102-4915 and
SPT-CL J2106-5844 and derive the respective cumulative distribution functions
of the exceedance over different mass thresholds. We also study the possibility
to use the GPD as a cosmological probe. Since in the maximum likelihood
estimation of the distribution parameters all the information from clusters
above the mass threshold is used, the GPD might offer an interesting
alternative to GEV-based methods that use only the maxima in patches. When
comparing the accuracy with which the parameters can be estimated, it turns out
that the patch-based modelling of maxima is superior to the Pareto approach. In
an ideal case, the GEV approach is capable to estimate the location parameter
with a percent level precision for less than 100 patches. This result makes the
GEV based approach potentially also interesting for cluster surveys with a
smaller area.Comment: 10 pages, 8 figures, MNRAS accepted, minor modifications to match the
accepted versio
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