484 research outputs found
VLT/VIMOS Observations of an Occulting Galaxy Pair: Redshifts and Effective Extinction Curve
We present VLT/VIMOS IFU observations of an occulting galaxy pair previously
discovered in HST observations. The foreground galaxy is a low-inclination
spiral disk, which causes clear attenuation features seen against the bright
bulge and disk of the background galaxy. We find redshifts of and z=0.065 for the foreground and background galaxy respectively.
This relatively small difference does not rule out gravitational interaction
between the two galaxies. Emission line ratios point to a star-forming, not
AGN-dominated foreground galaxy.
We fit the Cardelli, Clayton & Mathis (CCM) extinction law to the spectra of
individual fibres to derive slope () and normalization (). The
normalization agrees with the HST attenuation map and the slope is lower than
the Milky Way relation (), which is likely linked to the spatial
sampling of the disk. We speculate that the values of point to either
coherent ISM structures in the disk larger than usual ( kpc) or higher
starting values of , indicative of recent processing of the dust.
The foreground galaxy is a low stellar mass spiral () with a high dust content (). The dust disk geometry visible in the HST image would explain the
observed SED properties of smaller galaxies: a lower mean dust temperature, a
high dust-to-stellar mass ratio but relatively little optical attenuation.
Ongoing efforts to find occulting pairs with a small foreground galaxies will
show how common this geometry is.Comment: 16 pages, 3 tables, 13 figures, accepted for publication in MNRA
Self-regulated fueling of galaxy centers: Evidence for star formation feedback
Using new, high-resolution interferometric observations of the CO and HCN molecules, we directly compare the molecular and ionized components of the interstellar medium in the center of the nearby spiral galaxy IC 342, on spatial scales of 10 pc. The morphology of the tracers suggests that the molecular gas flow caused by a large-scale stellar bar has been strongly affected by the mechanical feedback from recent star formation activity within the central 100 pc in the nucleus of the galaxy. Possibly, stellar winds and/or supernova shocks originating in the nuclear star cluster have compressed, and likely pushed outward, the infalling molecular gas, thus significantly reducing the gas supply to the central 10 pc. Although our analysis currently lacks kinematic confirmation due to the face-on orientation of IC 342, the described scenario is supported by the generally observed repetitive nature of star formation in the nuclear star clusters of late-type spiral galaxies
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Nonverbal Synchrony: An Indicator of Clinical Communication Quality in Racially-Concordant and Racially-Discordant Oncology Interactions
Objectives
The aim of this cross-sectional study was to apply a novel software to measure and compare levels of nonverbal synchrony, as a potential indicator of communication quality, in video recordings of racially-concordant and racially-discordant oncology interactions. Predictions include that the levels of nonverbal synchrony will be greater during racially-concordant interactions than racially-discordant interactions, and that levels of nonverbal synchrony will be associated with traditional measures of communication quality in both racially-concordant and racially-discordant interactions.
Design
This is a secondary observational analysis of video-recorded oncology treatment discussions collected from 2 previous studies.
Setting
Two National Cancer Institute-designated Comprehensive Cancer Centers and another large urban cancer center.
Participants
Participants from Study 1 include 161 White patients with cancer and 11 White medical oncologists. Participants from Study 2 include 66 Black/African-American patients with cancer and 17 non-Black medical oncologists. In both studies inclusion criteria for patients was a recent cancer diagnosis; in Study 2 inclusion criteria was identifying as Black/African American.
Main outcome measures
Nonverbal synchrony and communication quality.
Results
Greater levels of nonverbal synchrony were observed in racially-discordant interactions than in racially-concordant interactions. Levels of nonverbal synchrony were associated with indicators of communication quality, and these associations were more consistently found in racially-discordant interactions.
Conclusion
This study advances clinical communication and disparities research by successfully applying a novel approach capturing the unconscious nature of communication, and revealing differences in communication in racially-discordant and racially-concordant oncology interactions. This study highlights the need for further exploration of nonverbal aspects relevant to patient-physician interactions
Ultrasound biomicroscopy findings of 25 G Transconjuctival sutureless (TSV) and conventional (20G) pars plana sclerotomy in the same patient
BACKGROUND: Transconjunctival Sutureless Vitrectomy (TSV) is a recent advancement in vitreo-retinal surgical techniques involving the use of 25 G instruments through self-sealing sclerotomies. It has been hypothesized that there may be less chance of vitreous and retinal herniation in the scleral wound as compared to conventional sclerotomy incision. However there are no reports on differences in 20 gauge and 25 gauge sclerotomies using ultrasound biomicroscopy (UBM). We report herein the differences in sclerotomies undertaken with 20 gauge (G) and 25 gauge instruments in the same patient. CASE PRESENTATION: Ultrasound biomicroscopy of the sclerotomy sites was done in the same patient in whom both 20 G and 25 G sclerotomies had to be constructed during pars plana vitrectomy and the differences were studied. On day 2, we observed a wide gape at the site that had been enlarged using a 20G MVR blade. In contrast, the other two sites made transconjunctivally using the 25G trocar showed only a mild gape. Significant gape continued to persist at the subsequent evaluations on day 7 and day 14 only at the port, which had been enlarged. CONCLUSION: Healing of a 25 G sclerotomy is expectedly quite rapid, with inability to detect the site of sclerotomy in a short duration of 2 weeks post-operatively. This is as opposed to conventional sclerotomies, which might take up to 6–8 weeks post-operatively for complete opposition
Percentile Queries in Multi-Dimensional Markov Decision Processes
Markov decision processes (MDPs) with multi-dimensional weights are useful to
analyze systems with multiple objectives that may be conflicting and require
the analysis of trade-offs. We study the complexity of percentile queries in
such MDPs and give algorithms to synthesize strategies that enforce such
constraints. Given a multi-dimensional weighted MDP and a quantitative payoff
function , thresholds (one per dimension), and probability thresholds
, we show how to compute a single strategy to enforce that for all
dimensions , the probability of outcomes satisfying is at least . We consider classical quantitative payoffs from
the literature (sup, inf, lim sup, lim inf, mean-payoff, truncated sum,
discounted sum). Our work extends to the quantitative case the multi-objective
model checking problem studied by Etessami et al. in unweighted MDPs.Comment: Extended version of CAV 2015 pape
The NICMOS Snapshot Survey of nearby Galaxies
We present ``snapshot'' observations with the NearInfrared Camera and
MultiObject Spectrometer (NICMOS) on board the Hubble Space Telescope (HST) of
94 nearby galaxies from the Revised Shapley Ames Catalog. Images with 0.2 as
resolution were obtained in two filters, a broad-band continuum filter (F160W,
roughly equivalent to the H-band) and a narrow band filter centered on the
Paschen alpha line (F187N or F190N, depending on the galaxy redshift) with the
51x51 as field of view of the NICMOS camera 3. A first-order continuum
subtraction is performed, and the resulting line maps and integrated Paschen
alpha line fluxes are presented. A statistical analysis indicates that the
average Paschen alpha surface brightness {\bf in the central regions} is
highest in early-type (Sa-Sb) spirals.Comment: Original contained error in flux calibration. Table 1 now has correct
Paschen Alpha fluxes. 14 pages LaTeX with JPEG and PS figures. Also available
at http://icarus.stsci.edu/~boeker/publications.htm
Elusive Active Galactic Nuclei
A fraction of active galactic nuclei do not show the classical Seyfert-type
signatures in their optical spectra, i.e. they are optically "elusive". X-ray
observations are an optimal tool to identify this class of objects. We combine
new Chandra observations with archival X-ray data in order to obtain a first
estimate of the fraction of elusive AGN in local galaxies and to constrain
their nature. Our results suggest that elusive AGN have a local density
comparable to or even higher than optically classified Seyfert nuclei. Most
elusive AGN are heavily absorbed in the X-rays, with gas column densities
exceeding 10^24 cm^-2, suggesting that their peculiar nature is associated with
obscuration. It is likely that in elusive AGN, the nuclear UV source is
completely embedded and the ionizing photons cannot escape, which prevents the
formation of a classical Narrow Line Region. Elusive AGN may contribute
significantly to the 30 keV bump of the X-ray background.Comment: accepted for publication in MNRAS Letters, 6 pages, 3 figures, typos
and references correcte
Free radical scavenging and antioxidant activity of allopurinol and oxypurinol in experimental lens-induced uveitis
Purpose. In addition to the inhibition of xanthine oxidase, allopurinol is known to act, dependent on the dose, as a free radical scavenger, an antioxidant, and a "scavenger" of hypochlorous acid. This activity was investigated using a model of lens-induced uveitis. Methods. Lipid peroxides (LPO) were determined in aqueous humor and in retinal tissue. Reduced and oxidized glutathione (GSH and GSSG) of the aqueous humor and myeloperoxidase (MPO) activity in the iris-ciliary body complex were analyzed. Allopurinol and oxypurinol concentrations were determined by high-performance liquid chromatography in aqueous humor and retinal tissue of both control eyes and eyes with uveitis. These measurements were performed 6 hours after intravenous application of allopurinol. Results. In lens-induced uveitis, LPO are significantly elevated, GSH is reduced, and GSSG and MPO are increased. A xanthine oxidase inhibition dose (<10 mg/kg body weight) of allopurinol showed no effects on oxidative tissue damage in the model used in this study. Higher doses, however, were able to reduce the oxidative damage. Allopurinol (20 mg/kg body weight) had slight effects on GSH and GSSG. All parameters improved using a dose of 50 mg/kg body weight; a dose of 100 mg/kg body weight only showed additional improvement in GSH and GSSG. There was no further change in the other parameters. Allopurinol and oxypurinol concentrations in aqueous humor and retinal tissue showed a dose dependency reaching scavenger concentrations after application of 50 mg/kg body weight of allopurinol. Conclusions. These results suggest that the xanthine oxidase mechanism plays a minor role in the oxidative tissue damage due to lens-induced uveitis. Free radicals and oxidants are generated by activated leukocytes; therefore, the effect of higher doses of allopurinol is due to its free radical scavenging and antioxidative activity. Invest Ophthalmol Vis Sci. 1994; 35:3897-3904. Allopurinol is widely used in clinical medicine for the treatment of hyperuricemia. A reduction in uric acid is achieved by the inhibition of the enzyme xanthine oxidase. In ischemic diseases, xanthine oxidase uses oxygen as a reduction equivalent, leading to the formation of superoxideanion radicals. Therefore
Galaxies with unusually high abundances of molecular hydrogen
A sample of 66 galaxies from the catalog of Bettoni et al. (CISM) with
anomalously high molecular-to-atomic hydrogen mass ratios (M_{mol}/M_{HI}>2) is
considered. The sample galaxies do not differ systematically from other
galaxies in the catalog with the same morphological types, in terms of their
photometric parameters, rotational velocities, dust contents, or the total mass
of gas in comparison with galaxies of similar linear sizes and disk angular
momentum. This suggests that the overabundance of is due to transition of
HI to H_2. Galaxies with bars and active nuclei are found more frequently among
galaxies which have M_{mol} estimates in CISM. In a small fraction of galaxies,
high M_{mol}/M_{HI} ratios are caused by the overestimation of M_{mol} due to a
low conversion factor for the translation of CO-line intensities into the
number of H_2 molecules along the line of sight. It is argued that the
"molecularization" of the bulk of the gas mass could be due 1) to the
concentration of gas in the inner regions of the galactic disks, resulting to a
high gas pressure and 2) to relatively low star-formation rate per unit mass of
molecular gas which indeed takes place in galaxies with high M_{mol}/M_{HI}
ratios.Comment: 11 pages,7 figures, published in Astronomy Report
The relationship between anti-mullerian hormone in women receiving fertility assessments and age at menopause in subfertile women: evidence from large population studies
<p>Context: Anti-Müllerian hormone (AMH) concentration reflects ovarian aging and is argued to be a useful predictor of age at menopause (AMP). It is hypothesized that AMH falling below a critical threshold corresponds to follicle depletion, which results in menopause. With this threshold, theoretical predictions of AMP can be made. Comparisons of such predictions with observed AMP from population studies support the role for AMH as a forecaster of menopause.</p>
<p>Objective: The objective of the study was to investigate whether previous relationships between AMH and AMP are valid using a much larger data set.</p>
<p>Setting: AMH was measured in 27 563 women attending fertility clinics.</p>
<p>Study Design: From these data a model of age-related AMH change was constructed using a robust regression analysis. Data on AMP from subfertile women were obtained from the population-based Prospect-European Prospective Investigation into Cancer and Nutrition (Prospect-EPIC) cohort (n = 2249). By constructing a probability distribution of age at which AMH falls below a critical threshold and fitting this to Prospect-EPIC menopausal age data using maximum likelihood, such a threshold was estimated.</p>
<p>Main Outcome: The main outcome was conformity between observed and predicted AMP.</p>
<p>Results: To get a distribution of AMH-predicted AMP that fit the Prospect-EPIC data, we found the critical AMH threshold should vary among women in such a way that women with low age-specific AMH would have lower thresholds, whereas women with high age-specific AMH would have higher thresholds (mean 0.075 ng/mL; interquartile range 0.038–0.15 ng/mL). Such a varying AMH threshold for menopause is a novel and biologically plausible finding. AMH became undetectable (<0.2 ng/mL) approximately 5 years before the occurrence of menopause, in line with a previous report.</p>
<p>Conclusions: The conformity of the observed and predicted distributions of AMP supports the hypothesis that declining population averages of AMH are associated with menopause, making AMH an excellent candidate biomarker for AMP prediction. Further research will help establish the accuracy of AMH levels to predict AMP within individuals.</p>
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