3,541 research outputs found
Unique and interactive associations of callous-unemotional traits, impulsivity and narcissism with child and adolescent Conduct Disorder symptoms
The construct of psychopathy remains underrepresented in the clinical diagnosis of Conduct Disorder (CD) as the Diagnostic and Statistical Manual of Mental Disorders 5th edition (DSM-5) only addresses one out of the three dimensions of child psychopathy, Callous Unemotional (CU) traits. This study tests if and to what extent there are unique and interactive associations of CU traits, impulsivity, and grandiosity with child and adolescent CD symptoms. Data were collected from two separate community samples of children (N = 1599; Mage = 9.46, SD = 1.65; 52% female) and adolescents (N = 2719; Mage = 16.99, SD = 0.99; 49% female), who were followed longitudinally after a year. Hierarchical linear regression analyses were conducted, testing cross-sectional and longitudinal associations with CD symptoms, taking into account all three psychopathy dimensions. The cross-sectional findings indicate that only youth presenting a combination of all three psychopathy dimensions scored above the clinical cut-off score for CD. On the other hand, longitudinal findings provided evidence that the combination of high initial levels of CD and CU traits as well as the combination between CD, grandiosity, and impulsivity can lead to clinical levels of future CD symptoms. Findings also indicated that CU traits and impulsivity more strongly predicted adolescent than child CD symptoms, and that CU traits were more strongly associated with boys' than girls' CD symptoms. Findings support the inclusion of CU traits as a specifier for the diagnosis of CD, and provide evidence that other psychopathy dimensions can also help clinicians to better understand and treat youth with CD, and should be considered for future revisions of the DSM
A Very Radio-Loud Narrow-Line Seyfert 1: PKS 2004-447
We have discovered a very radio-loud Narrow-Line Seyfert 1 candidate: PKS
2004-447. This Seyfert is consistent with the formal definition for NLS1s,
although it does not have quite the same spectral features as some typical
members of this subclass. Only ROSAT survey data is available at X-ray
wavelengths, so it has not been possible to compare this source with other
NLS1s at these wavelengths. A full comparison of this source with other members
of the subclass will improve our physical understanding of NLS1s. In addition,
using standard calculations, we estimate the central black hole to have a mass
of . This does not agree with predictions in the
literature, that radio-loud AGN host very massive black holes.Comment: 15 pages, 4 figures, accepted for publication in ApJ, minor typos
change
The host galaxies of three radio-loud quasars: 3C 48, 3C 345, and B2 1425+267
Observations with the Wide-Field/Planetary Camera-2 of the Hubble Space
Telescope (HST) are presented for three radio-loud quasars: 3C 48 (z=0.367), B2
1425+267 (z=0.366), and 3C 345 (z=0.594). All three quasars have luminous (~4
L^*) galaxies as hosts, which are either elliptical (B2 1425+267 and 3C 345) or
interacting (3C 48), and all hosts are 0.5 - 1.0 mag bluer in (V-I) than other
galaxies with the same overall morphology at similar redshifts to the quasars.
The host of 3C 48 has many H II regions and a very extended tidal tail.
All nine of the radio-loud quasars studied here and in Bahcall et al. (1997)
either have bright elliptical hosts or occur in interacting systems. There is a
robust correlation between the radio emission of the quasar and the luminosity
of host galaxy; the radio-loud quasars reside in galaxies that are on average
about 1 mag brighter than hosts of the radio-quiet quasars.Comment: Accepted for publication in ApJ. 3 postscript and 3 jpeg figures.
Original figures may be found in ftp://eku.sns.ias.edu/pub/sofia/RadioLoud
X-ray-emitting Atmospheres of B2 Radio Galaxies
We report ROSAT PSPC spatial and spectral analysis of the eight B2 radio
galaxies NGC 315, NGC 326, 4C 35.03, B2 0326+39, NGC 2484, B2 1040+31, B2
1855+37, and 3C 449, expected to be representative of the class of low-power
radio galaxies. Multiple X-ray components are present in each, and the gas
components have a wide range of linear sizes and follow an extrapolation of the
cluster X-ray luminosity/temperature correlation, implying that there is no
relationship between the presence of a radio galaxy and the gas fraction of the
environment. No large-scale cooling flows are found. There is no correlation of
radio-galaxy size with the scale or density of the X-ray atmosphere. This
suggests that it is processes on scales less than those of the overall gaseous
environments which are the major influence on radio-source dynamics. The
intergalactic medium is usually sufficient to confine the outer parts of the
radio structures, in some cases even to within 5 kpc of the core. In the case
of NGC 315, an extrapolation suggests that the pressure of the atmosphere may
match the minimum pressure in the radio source over a factor of about 40 in
linear size (a factor of about 1600 in pressure).Comment: 34 pages, including 10 figures, using aasms4.sty To appear in the Ap
Direct CP, T and/or CPT violations in the K^0-\bar{K^0} system - Implications of the recent KTeV results on decays -
The recent results on the CP violating parameters Re(e'/e) and \Delta\phi =
\phi_{00}-\phi_{+-} reported by the KTeV Collaboration are analyzed with a view
to constrain CP, T and CPT violations in a decay process. Combining with some
relevant data compiled by the Particle Data Group, we find Re(e_2-e_0) = (0.85
+- 3.11)*10^{-4} and Im(e_2-e_0) = (3.2 +- 0.7)*10^{-4}, where Re(e_I) and
Im(e_I) represent respectively CP/CPT and CP/T violations in decay of K^0 and
\bar{K^0} into a 2\pi state with isospin I.Comment: 7 pages, No figure
Optical spectroscopy of faint gigahertz peaked spectrum sources
We present spectroscopic observations of a sample of faint Gigahertz Peaked
Spectrum (GPS) radio sources drawn from the Westerbork Northern Sky Survey
(WENSS). Redshifts have been determined for 19 (40%) of the objects. The
optical spectra of the GPS sources identified with low redshift galaxies show
deep stellar absorption features. This confirms previous suggestions that their
optical light is not significantly contaminated by AGN-related emission, but is
dominated by a population of old (>9 Gyr) and metal-rich (>0.2 [Fe/H]) stars,
justifying the use of these (probably) young radio sources as probes of galaxy
evolution. The optical spectra of GPS sources identified with quasars are
indistinguishable from those of flat spectrum quasars, and clearly different
from the spectra of Compact Steep Spectrum (CSS) quasars. The redshift
distribution of the GPS quasars in our radio-faint sample is comparable to that
of the bright samples presented in the literature, peaking at z ~ 2-3. It is
unlikely that a significant population of low redshift GPS quasars is missed
due to selection effects in our sample. We therefore claim that there is a
genuine difference between the redshift distributions of GPS galaxies and
quasars, which, because it is present in both the radio-faint and bright
samples, can not be due to a redshift-luminosity degeneracy. It is therefore
unlikely that the GPS quasars and galaxies are unified by orientation, unless
the quasar opening angle is a strong function of redshift. We suggest that the
GPS quasars and galaxies are unrelated populations and just happen to have
identical observed radio-spectral properties, and hypothesise that GPS quasars
are a sub-class of flat spectrum quasars.Comment: LaTeX, 13 pages. Accepted by MNRAS. For related papers see
http://www.ast.cam.ac.uk/~snelle
Sub-milliarcsecond Imaging of Quasars and AGN
We have used the VLBA at 15 GHz to image the structure of 132 strong compact
AGN and quasars with a resolution better than one milliarcsecond and a dynamic
range typically exceeding 1000 to 1. These observations were made as part of a
program to investigate the sub-parsec structure of quasars and AGN and to study
the changes in their structure with time. Many of the sources included in our
study, particularly those located south of +35 degrees, have not been
previously imaged with milliarcsecond resolution. Each of the sources has been
observed at multiple epochs. In this paper we show images of each of the 132
sources which we have observed. For each source we present data at the epoch
which had the best quality data. The milliarcsecond jets generally appear
one-sided but two-sided structure is often found in lower luminosity radio
galaxies and in high luminosity quasars with gigahertz peaked spectra. Usually
the structure is unresolved along the direction perpendicular to the jet, but a
few sources have broad plumes. In some low luminosity radio galaxies, the
structure appears more symmetric at 2 cm than at long wavelengths. The apparent
long wavelength symmetry in these sources is probably due to absorption by
intervening material. A few sources contain only a single component with any
secondary feature at least a thousand times weaker. We find no obvious
correlation of radio morphology and the detection of gamma-ray emission by
EGRET.Comment: 19 pages, 3 tables, 3 figures. Figure 2 (132 contour diagrams) is
long and is omitted here. Figure 2 may be viewed at
http://www.cv.nrao.edu/2cmsurvey/ In press, Astronomical Journal, April 199
Effelsberg 100-m polarimetric observations of a sample of Compact Steep-Spectrum sources
We completed observations with the Effelsberg 100-m radio telescope to
measure the polarised emission from a complete sample of Compact Steep-Spectrum
sources. We observed the sources at four different frequencies. We complemented
these measurements with polarisation parameters at 1.4 GHz derived from the
NVSS. Previous single dish measurements were taken from the catalogue of Tabara
and Inoue. The depolarisation index DP was computed for four pairs of
frequencies. A drop in the fractional polarisation appeared in the radio
emission when observing at frequencies below about 2 GHz. Rotation measures
were derived for about 25% of the sources in the sample. The values range from
about -20 rad/m**2} found for 3C138 to 3900 rad/m**2 in 3C119. In all cases,
the lambda**2 law is closely followed. The presence of a foreground screen as
predicted by the Tribble model or with ``partial coverage'' as defined by
ourselves can explain the polarimetric behaviour of the CSS sources detected in
polarisation by the present observations. Indication of repolarisation at lower
frequencies was found for some sources. A case of possible variability in the
fractional polarisation is also suggested. The most unexpected result was found
for the distribution of the fractional polarisations versus the linear sizes of
the sources. Our results appear to disagree with the findings of Cotton and
collaborators and Fanti and collaborators for the B3-VLA sample of CSS sources,
the so-called ``Cotton effect''. This apparent contradiction may, however, be
caused by the large contamination of the sample by quasars with respect to the
B3-VLA.Comment: Astronomy and Astrophysycs, in pres
Polarized Radio Sources: A Study of Luminosity, Redshift and Infrared Colors
The Dominion Radio Astrophysical Observatory Deep Field polarization study
has been matched with the Spitzer Wide-Area Infrared Extragalactic survey of
the European Large Area Infrared Space Observatory Survey North 1 field. We
have used VLA observations with a total intensity rms of 87 microJy beam^-1 to
match SWIRE counterparts to the radio sources. Infrared color analysis of our
radio sample shows that the majority of polarized sources are elliptical
galaxies with an embedded active galactic nucleus. Using available redshift
catalogs, we found 429 radio sources of which 69 are polarized with redshifts
in the range of 0.04 < z <3.2. We find no correlation between redshift and
percentage polarization for our sample. However, for polarized radio sources,
we find a weak correlation between increasing percentage polarization and
decreasing luminosity.Comment: 35 pages, 12 figures, accepted for publication in The Astrophysical
Journa
A Robust SVM Color-Based Food Segmentation Algorithm for the Production Process of a Traditional Carasau Bread
In this paper, we address the problem of automatic image segmentation methods applied to the partial automation of the production process of a traditional Sardinian flatbread called pane Carasau for assuring quality control. The study focuses on one of the most critical activities for obtaining an efficient degree of automation: the estimation of the size and shape of the bread sheets during the production phase, to study the shape variations undergone by the sheet depending on some environmental and production variables. The knowledge can thus be used to create a system capable of predicting the quality of the shape of the dough produced and empower the production process. We implemented an image acquisition system and created an efficient machine learning algorithm, based on support vector machines, for the segmentation and estimation of image measurements for Carasau bread. Experiments demonstrated that the method can successfully achieve accurate segmentation of bread sheets images, ensuring that the dimensions extracted are representative of the sheets coming from the production process. The algorithm proved to be fast and accurate in estimating the size of the bread sheets in various scenarios that occurred over a year of acquisitions. The maximum error committed by the algorithm is equal to the 2.2% of the pixel size in the worst scenario and to 1.2% elsewhere
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