457 research outputs found
Constraints on the Inner Regions of Lensing Galaxies from Central Images using a Recent AGN Offset Distribution
In gravitational lensing, central images in quads can serve as a powerful
probe of the inner regions of lens galaxies. The presence of an offset central
supermassive black hole (SMBH) has the potential to distort the time-delay
surface in a way such that 3 central images form: a strongly de-magnified image
near the SMBH, and two less de-magnified (and potentially observable) images at
a central maximum and saddle point. Using a quad lens macro model, we simulate
the constraints that could be placed on various lens galaxy parameters based on
their central images probability of detection or non-detection. Informed by a
recent low-redshift distribution of off-nucleus AGN, we utilize Bayesian
inference to constrain the mean SMBH off-nucleus distance and galactic core
radius for a sample of 6 quads. In general, we find that a detection of the
central image in any quad would favor larger SMBH off-nucleus distances and
galaxy core sizes. Assuming a linear relationship between core radii and
velocity dispersion , these results similarly imply strong
constraints on , where the likely case of a central image non-detection in
each quad constraining to kpc
km s. Our results show that tight constraints on lens galaxy parameters
can be made regardless of a detection or non-detection of a central image.
Therefore, we recommend observational searches for the central image, possibly
using our suggested novel detection technique in UV filters, to formalize
stronger constraints on lens galaxy parameters.Comment: MNRAS, Accepted, 20 pages, 15 figure
Chest ultrasound in italian geriatric wards: Use, applications and clinicians’ attitudes
Background and aims. Bedside chest ultrasound has emerged as a versatile and accurate diagnostic tool for the management of respiratory conditions in several clinical settings, integrating traditional imaging. The current utilization of this technique in geriatric hospital wards is still unknown. Our aim was to assess availability, uses and applications of chest ultrasonography in a convenience sample of 25 Italian geriatric wards. Methods. A questionnaire, based on the current literature state-of-the-art, was e-mailed to head doctors of geriatric wards of Italian hospitals. The questionnaire explored ultrasound equipment availability, practice of chest ultrasound, expertise of ward physicians, clinical indications, and perceived impact on patient care. Results. Ultrasound equipment was available in 92% of wards, and chest ultrasound was performed in 82% of cases. Among the wards where chest ultrasound was performed, it was considered as routine assessment in only 52% of cases, mainly for diagnosis of pleural effusions (95%) and acute heart failure (89%), assessment of volemic state (79%), and assistance to invasive procedures (79%). It was used in emergency/ urgency assessment of acute dyspnea in only 53% of cases. In most wards, only three or less physicians were able to perform chest ultrasound. In 53% of cases, head doctors declared that they perceived benefits of chest ultrasound in patient care in only selected cases. Conclusions. Chest ultrasound utilization in Italian geriatric wards is inhomogeneous, and the number of trained physicians is still limited. Geriatricians’ attitude towards chest ultrasound is generally cautious. Research and training programs are needed to spread the correct use of this technique in geriatric practice
Ultrasound Evaluation of Diaphragmatic Mobility and Contractility After Osteopathic Manipulative Techniques in Healthy Volunteers : A Prospective, Randomized, Double-Blinded Clinical Trial
Objective: The purpose of this study was to investigate the effect of a session of osteopathic manipulative techniques on diaphragmatic motion and thickness in healthy participants. Methods: This was a prospective, randomized, double-blinded, case vs sham vs control clinical trial performed in an outpatient osteopathic clinic in Rome, Italy. Sixty-seven healthy participants, mean age 40.4 \ub1 14.5 years, received an ultrasound evaluation of diaphragmatic motion and thickness, followed by a systematic osteopathic evaluation. After randomization, the experimental group (n = 22) received osteopathic manipulation, whereas the sham (n = 22) and the control (n = 22) groups had a light touch approach and simple observation, respectively. After a 1-session intervention, new osteopathic and ultrasound assessments were repeated in all participants. Results: A statistically significant increase in diaphragmatic mobility was observed in the experimental group after the osteopathic manipulation (\u394 = 14.5 mm, P < .001; analysis of variance P < .001 vs both sham: \u394 = -0.22 mm, and control: \u394 = -2.09 mm groups). A strong linear relationship was observed between the diaphragmatic motion gradient, measured with ultrasonography, and the score assigned by the operator evaluating the change of diaphragm mobility after intervention. Conclusion: Osteopathic techniques used in this study improved the diaphragmatic motion (but not the muscle thickness) in healthy participants. Further studies are needed to confirm our findings and eventually identify the clinical conditions that may benefit from osteopathic manipulative treatment of the diaphragm
Predicting the redshift 2 Halpha luminosity function using [OIII] emission line galaxies
Upcoming space-based surveys such as Euclid and WFIRST-AFTA plan to measure
Baryonic Acoustic Oscillations (BAOs) in order to study dark energy. These
surveys will use IR slitless grism spectroscopy to measure redshifts of a large
number of galaxies over a significant redshift range. In this paper, we use the
WFC3 Infrared Spectroscopic Parallel Survey (WISP) to estimate the expected
number of Halpha (Ha) emitters observable by these future surveys. WISP is an
ongoing HST slitless spectroscopic survey, covering the 0.8-1.65micron
wavelength range and allowing the detection of Ha emitters up to z~1.5 and
[OIII] emitters to z~2.3. We derive the Ha-[OIII] bivariate line luminosity
function for WISP galaxies at z~1 using a maximum likelihood estimator that
properly accounts for uncertainties in line luminosity measurement, and
demonstrate how it can be used to derive the Ha luminosity function from
exclusively fitting [OIII] data. Using the z~2 [OIII] line luminosity function,
and assuming that the relation between Ha and [OIII] luminosity does not change
significantly over the redshift range, we predict the Ha number counts at z~2 -
the upper end of the redshift range of interest for the future surveys. For the
redshift range 0.7<z<2, we expect ~3000 galaxies/deg^2 for a flux limit of
3x10^{-16} ergs/s/cm^2 (the proposed depth of Euclid galaxy redshift survey)
and ~20,000 galaxies/deg^2 for a flux limit of ~10^{-16} ergs/s/cm^2 (the
baseline depth of WFIRST galaxy redshift survey).Comment: Minor revisions to match accepted ApJ versio
Old and young bulges in late-type disk galaxies
ABRIDGED: We use HSTACS and NICMOS imaging to study the structure and colors
of a sample of nine late-type spirals. We find: (1) A correlation between bulge
and disks scale-lengths, and a correlation between the colors of the bulges and
those of the inner disks. Our data show a trend for bulges to be more
metal-enriched than their surrounding disks, but otherwise no simple
age-metallicity connection between these systems; (2) A large range in bulge
stellar population properties, and, in particular, in stellar ages.
Specifically, in about a half of the late-type bulges in our sample the bulk of
the stellar mass was produced recently. Thus, in a substantial fraction of the
z=0 disk-dominated bulged galaxies, bulge formation occurs after the
formation/accretion of the disk; (3) In about a half of the late-type bulges in
our sample, however, the bulk of the stellar mass was produced at early epochs;
(4) Even these "old" late-type bulges host a significant fraction of stellar
mass in a young(er) c component; (5) A correlation for bulges between stellar
age and stellar mass, in the sense that more massive late-type bulges are older
than less massive late-type bulges. Since the overall galaxy luminosity (mass)
also correlates with the bulge luminosity (mass), it appears that the galaxy
mass regulates not only what fraction of itself ends up in the bulge component,
but also "when" bulge formation takes place. We show that dynamical friction of
massive clumps in gas-rich disks is a plausible disk-driven mode for the
formation of "old" late-type bulges. If disk evolutionary processes are
responsible for the formation of the entire family of late-type bulges, CDM
simulations need to produce a similar number of initially bulgeless disks in
addition to the disk galaxies that are observed to be bulgeless at z=0.Comment: ApJ in press; paper with high resolution figures available at
http://www.exp-astro.phys.ethz.ch/carollo/carollo1_2006.pdf; B, I, and H
surface brightness profiles published in electronic tabular for
Relationship between bone cross-sectional area and indices of peripheral artery disease
Most studies on the relationship between bone mineral density and atherosclerosis have used dual-energy X-ray absorptiometry, but this method is relatively insensitive to bone geometry. The aim of this study was to investigate the relationship between bone area and indices of carotid and peripheral atherosclerosis. We studied 841 persons aged 65 years or older (women = 444, mean age 73.8 years; men = 397, mean age = 75.3 years) enrolled in the InCHIANTI study and free from active malignancies, chronic use of bisphosphonates or steroids, and estrogen replacement therapy. The tibial cortical and total cross-sectional area (CSA) were measured by peripheral quantitative computed tomography and their ratio was calculated (cortical/total cross-sectional area ratio, cCSA/tCSA); carotid plaques were screened by echography, and peripheral artery disease (PAD) was defined as an ankle/brachial index <0.9 or presence of intermittent claudication. No association between cCSA/tCSA and atherosclerosis was observed in men. In women, lower cCSA/tCSA was associated with both carotid plaques [odds ratio (OR) for lowest vs. best quartile = 2.09, 95 % confidence interval (CI) 1.2-3.68] and PAD (OR = 3.43, 95 % CI 1.58-8.12). After correction for potential confounders (age since menopause, body mass index, Parathyroid hormone, vitamin D, leptin, DHEA-S, testosterone, physical activity, chronic obstructive pulmonary disease, and reduced renal function), the association was not confirmed. According to partial logistic regression, the carotid plaque-cCSA/tCSA association, but not the PAD-cCSA/tCSA association, was mostly dependent on years since menopause. In women the association between osteoporosis and carotid plaques likely reflects hormonal deprivation, whereas that between osteoporosis and PAD seems multifactorial in origin. © 2013 Springer Science+Business Media New York
Discovery of Three Distant, Cold Brown Dwarfs in the WFC3 Infrared Spectroscopic Parallels Survey
We present the discovery of three late type (>T4) brown dwarfs, including a
probable Y dwarf, in the WFC3 Infrared Spectroscopic Parallels (WISP) Survey.
We use the G141 grism spectra to determine the spectral types of the dwarfs and
derive distance estimates based on a comparison with nearby T dwarfs with known
parallaxes. These are the most distant spectroscopically confirmed T/Y dwarfs,
with the farthest at an estimated distance of ~400 pc. We compare the number of
cold dwarfs found in the WISP survey with simulations of the brown dwarf mass
function. The number found is generally consistent with an initial stellar mass
function dN/dM \propto M^{-\alpha} with \alpha = 0.0--0.5, although the
identification of a Y dwarf is somewhat surprising and may be indicative of
either a flatter absolute magnitude/spectral type relation than previously
reported or an upturn in the number of very late type brown dwarfs in the
observed volume.Comment: Accepted for publication by ApJ Letters. 10 pages, 2 figure
A case of Brucella endocarditis in association with subclavian artery thrombosis
Brucellosis is a common zoonosis, endemic in Mediterranean countries, and caused by bacteria of Brucella genus. Brucellosis is a systemic infection and the clinical presentation varies widely from asymptomatic and mild to severe disease. Cardiovascular complications are extremely rare. We present a case of arterial thrombosis in a previously healthy young patient with Brucella endocarditis. Careful attention must be paid to any sign or symptom of thrombosis in patients affected by brucellosis, regardless of the presence of endocarditis and cardiovascular risk factors.
PMID:22844622[PubMed] PMCID:PMC3400327Free PMC Articl
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