2,042 research outputs found
Gigahertz Peaked Spectrum sources from the Jodrell Bank-VLA Astrometric Survey
Observations with MERLIN at 408 MHz have been used to establish the
low-frequency part of the spectra of more than a hundred compact radio sources
taken from the part of the Jodrell Bank--VLA Astrometric Survey limited by 35
deg. < \delta < 75 deg. These sources were selected from JVAS and other
catalogues to have convex spectra between 1.4 and 8.4 GHz, characteristic of
Gigahertz Peaked Spectrum (GPS) sources. We have confirmed convex shapes of the
spectra of 76 objects (one half of our initial candidates) thereby yielding the
largest genuine sample of GPS sources compiled so far. Seven of 17 identified
quasars in the sample have large (z\ga 2) redshifts.Comment: 18 pages, 2 figures, minor corrections. To appear in: A&A Suppl. vol.
135 (March 1999
X-ray Spectral Survey of WGACAT Quasars, II: Optical and Radio Properties of Quasars with Low Energy X-ray Cut-offs
We have selected quasars with X-ray colors suggestive of a low energy
cut-off, from the ROSAT PSPC pointed archive. We examine the radio and optical
properties of these 13 quasars. Five out of the seven quasars with good optical
spectra show associated optical absorption lines, with two having high delta-v
candidate systems. Two other cut-off quasars show reddening associated with the
quasar. We conclude that absorption is highly likely to be the cause of the
X-ray cut-offs, and that the absorbing material associated with the quasars,
not intervening along the line-of-sight. The suggestion that Gigahertz Peaked
Sources are associated with X-ray cut-offs remains unclear with this expanded
sample.Comment: 17 pages, LaTeX, including 2 Tables and 1 figure. Ap.J. in pres
Correction to: inflammation is a target of medical treatment for lower urinary tract symptoms associated with benign prostatic hyperplasia
The article “Inflammation is a target of medical treatment for lower urinary tract symptoms associated with benign prostatic hyperplasia”, written by Cosimo De Nunzio, Andrea Salonia, Mauro Gacci and Vincenzo Ficarra was originally published electronically on the publisher’s internet portal on 14 February 2020 without open access
Discovery of 21cm absorption in a DLA towards TXS 0311+430: The first low spin temperature absorber at z > 1
We report the detection of HI 21 cm absorption from the damped
Lyman- system (DLA) towards TXS 0311+430, with the Green Bank
Telescope. The 21 cm absorption has a velocity spread (between nulls) of km s and an integrated optical depth of km s. We also present new Giant Metrewave Radio
Telescope 602 MHz imaging of the radio continuum. TXS 0311+430 is unresolved at
this frequency, indicating that the covering factor of the DLA is likely to be
high. Combining the integrated optical depth with the DLA HI column density of
\nhi = \cm, yields a spin temperature of K, assuming a covering factor of unity. This is the first case of
a low spin temperature ( DLA and is among the lowest
ever measured in any DLA. Indeed, the measured for this DLA is similar to
values measured in the Milky Way and local disk galaxies. We also determine a
lower limit (Si/H) solar for the DLA metallicity, amongst the
highest abundances measured in DLAs at any redshift. Based on low redshift
correlations, the low , large 21 cm absorption width and high metallicity
all suggest that the DLA is likely to arise in a massive,
luminous disk galaxy.Comment: 5 pages, 3 figures. Accepted for publication in MNRAS (Letters
A Multi-Cloud Warm-Absorber Model for NGC 4051
A multi-cloud model is presented which explains the soft X-ray excess in NGC
4051 and, consistently, the optical line spectrum and the SED of the continuum.
The clouds are heated and ionized by the photoionizing flux from the active
center and by shocks. Diffuse radiation, partly absorbed throughout the clouds,
nicely fits the bump in the soft X-ray domain, while bremsstrahlung radiation
from the gaseous clouds contribute to the fit of the continuum SED. Debris of
high density fragmented clouds are necessary to explain the absorption oxygen
throats observed at 0.87 keV and 0.74 keV. The debris are heated by shocks of
about 200-300 km/s. Low velocity (100 km/s)-density (100 cm-3) clouds
contribute to the line and continuum spectra, as well as high velocity (1000
km/s)-density (8000 cm-3) clouds which are revealed by the FWHM of the line
profiles. The SED in the IR is explained by reradiation of dust, however, the
dust-to-gas ratio is not particularly high. Radio emission is well fitted by
synchrotron radiation created at the shock front by Fermi mechanism.Comment: 19 pages + 3 figures PostScrip
Advanced Technologies for Oral Controlled Release: Cyclodextrins for oral controlled release
Cyclodextrins (CDs) are used in oral pharmaceutical formulations, by means of inclusion complexes formation, with the following advantages for the drugs: (1) solubility, dissolution rate, stability and bioavailability enhancement; (2) to modify the drug release site and/or time profile; and (3) to reduce or prevent gastrointestinal side effects and unpleasant smell or taste, to prevent drug-drug or drug-additive interactions, or even to convert oil and liquid drugs into microcrystalline or amorphous powders. A more recent trend focuses on the use of CDs as nanocarriers, a strategy that aims to design versatile delivery systems that can encapsulate drugs with better physicochemical properties for oral delivery. Thus, the aim of this work was to review the applications of the CDs and their hydrophilic derivatives on the solubility enhancement of poorly water soluble drugs in order to increase their dissolution rate and get immediate release, as well as their ability to control (to prolong or to delay) the release of drugs from solid dosage forms, either as complexes with the hydrophilic (e.g. as osmotic pumps) and/ or hydrophobic CDs. New controlled delivery systems based on nanotechonology carriers (nanoparticles and conjugates) have also been reviewed
Engaging men with penile cancer in qualitative research: reflections from an interview-based study.
To explore the challenges of engaging men with penile cancer in qualitative interview research
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