6,656 research outputs found
A Deep Photometric Look at Two of Andromeda's Dwarf Spheroidals: X and XVII
We use deep wide-field photometry from the Large Binocular Camera to study
the stellar and structural properties of the recently discovered Andromeda X
and Andromeda XVII (And X and And XVII) dwarf galaxies. Using the mean apparent
magnitude of the horizontal branch (HB), we derive distances of 621 +- 20 kpc
to And X and 734+- 23 kpc to And XVII, closer by >60 kpc than the previous
estimates which were based on red giant branch (RGB) observations. Thus our
results warrant against the use of the RGB tip method for determining distances
to systems with sparsely populated RGBs, and show how crucial HB observations
are in obtaining accurate distances in systems such as these. We find that And
X is a relatively faint (MV = -7.36), highly elongated (e = 0.48) system at a
distance of 174 +- 62 kpc from Andromeda. And XVII is brighter (MV = -8.61)
with an M31-centric distance of 73 kpc which makes it one of the closest
satellites to Andromeda. Both galaxies are metal-poor: we derive =-2.2
for And X, while And XVII shows = -2.0, consistent with the relation
of higher luminosity dwarfs being more metal- rich. Additionally, both galaxies
show considerable intrinsic spreads in metallicity (0.2 and 0.3 dex for And X
and And XVII respectively), consistent with multiple stellar populations.Comment: 8 pages, 6 figure
Meaningful characterisation of perturbative theoretical uncertainties
We consider the problem of assigning a meaningful degree of belief to
uncertainty estimates of perturbative series. We analyse the assumptions which
are implicit in the conventional estimates made using renormalisation scale
variations. We then formulate a Bayesian model that, given equivalent initial
hypotheses, allows one to characterise a perturbative theoretical uncertainty
in a rigorous way in terms of a credibility interval for the remainder of the
series. We compare its outcome to the conventional uncertainty estimates in the
simple case of the calculation of QCD corrections to the e+e- -> hadrons
process. We find comparable results, but with important conceptual differences.
This work represents a first step in the direction of a more comprehensive and
rigorous handling of theoretical uncertainties in perturbative calculations
used in high energy phenomenology.Comment: 28 pages, 5 figures. Language modified in order to make it more
'bayesian'. No change in results. Version published in JHE
O-Allylated Pudovik and Passerini Adducts as Versatile Scaffolds for Product Diversification
International audienc
An additional set of phages to characterize epidemic methicillin-resistant Staphylococcus aureus strains from Spain (1989-92).
In recent years, methicillin-resistant Staphylococcus aureus (MRSA) isolates in Spain have increased dramatically; in 1986 there were only 1.2% MRSA amongst all nosocomial Staphylococcus aureus (SA) isolates, by 1989 this percentage had risen to 44% in some hospital causing a very serious epidemic situation in the country. We have characterized these isolates by direct, reverse and Fisk phage typing and we have also looked for an additional local set of phages to help us to differentiate these strains. We have been able to differentiate an epidemic strain from other MRSA strains which cause sporadic hospital outbreaks, and we have also distinguished between some variants of the epidemic strain.This research has been supported by a grant from the Fondo de Investigaciones Sanitarias de la Seguridad Social (FISS), Ministerio de Sanidad y Consumo, Spain; No. 93/0144.S
Transcatheter heart valve selection and permanent pacemaker implantation in patients with pre-existent right bundle branch block
Background-Right bundle branch block is an established predictor for new conduction disturbances and need for a permanent pacemaker (PPM) after transcatheter aortic valve replacement. The aim of the study was to evaluate the absolute rates of transcatheter aortic valve replacement related PPM implantations in patients with pre-existent right bundle branch block and categorize for different transcatheter heart valves. Methods and Results-We pooled data on 306 transcatheter aortic valve replacement patients from 4 high-volume centers in Europe and selected those with right bundle branch block at baseline without a previously implanted PPM. Logistic regression was used to evaluate whether PPM rate differed among transcatheter heart valves after adjustment for confounders. Mean age was 83±7 years and 63% were male. Median Society of Thoracic Surgeons score was 6.3 (interquartile range, 4.1-10.2). The following transcatheter valve designs were used: Medtronic CoreValve (n=130; Medtronic, Minneapolis, MN); Edwards Sapien XT (ES-XT; n=124) and Edwards Sapien 3 (ES-3; n=32; Edwards Lifesciences, Irvine, CA); and Boston Scientific Lotus (n=20; Boston Scientific Corporation, Marlborough, MA). Overall permanent pacemaker implantation rate post-transcatheter aortic valve replacement was 41%, and per valve design: 75% with Lotus, 46% with CoreValve, 32% with ES-XT, and 34% with ES-3. The indication for PPM implantation was total atrioventricular block in 98% of the cases. Lotus was associated with a higher PPM rate than all other valves. PPM rate did not differ between ES-XT and ES-3. Ventricular paced rhythm at 30-day and 1-year follow-up was present in 81% at 89%, respectively. Conclusions-Right bundle branch block at baseline is associated with a high incidence of PPM implantation for all transcatheter heart valves. PPM rate was highest for Lotus and lowest for ES-XT and ES-3. Pacemaker dependency remained high during followup
A deep Large Binocular Telescope view of the Canes Venatici I dwarf galaxy
We present the first deep color-magnitude diagram of the Canes Venatici I
(CVnI) dwarf galaxy from observations with the wide field Large Binocular
Camera on the Large Binocular Telescope. Reaching down to the main-sequence
turnoff of the oldest stars, it reveals a dichotomy in the stellar populations
of CVnI: it harbors an old (> 10 Gyr), metal-poor ([Fe/H] ~ -2.0) and spatially
extended population along with a much younger (~ 1.4-2.0 Gyr), 0.5 dex more
metal-rich, and spatially more concentrated population. These young stars are
also offset by 64_{-20}^{+40} pc to the East of the galaxy center. The data
suggest that this young population, which represent ~ 3-5 % of the stellar mass
of the galaxy within its half-light radius, should be identified with the
kinematically cold stellar component found by Ibata et al. (2006). CVnI
therefore follows the behavior of the other remote MW dwarf spheroidals which
all contain intermediate age and/or young populations: a complex star formation
history is possible in extremely low-mass galaxies.Comment: 4 pages, 3 figures, accepted for publication in ApJL. Minor changes,
conclusions unchange
Estimating bird flight height using 3-D photogrammetry
Harnessing wind or solar power have become popular “green” options for energy production. However, colliding with wind turbine blades or being burned by concentrated solar flux around power towers can present a substantial threat to birds. Assessing the severity of this risk to different bird species requires accurate estimates of their flight height. We developed a three-dimensional (3-D) stereophotogrammetric approach to determine bird flight heights. The accuracy of four varying stereophotogrammetric camera layouts was compared between each other and against laser-based rangefinder measurements of static structures. Bird flight heights were measured and compared between species, and repetitive photographic captures over short time periods were tested for autocorrelation. Three out of four camera layouts performed equally well when measuring static structures at distances of up to 100 m (0.0 ± 0.3%; or 0.00 ± 0.03 m error), better than laser-based rangefinders (0.3 ± 4.8%; or 0.12 ± 0.51 m error) on a small target. Photogrammetrically measured flight heights were precise to 0.07 ± 0.05 m up to ~275 m away and to within 1 m at 400 m, and measurable up to ~535 m away. Using this tested approach, repetitive, sequential flight heights of moving birds were significantly autocorrelated compared to random flight heights (P = 0.001). Species-specific flight heights were distinct, practically demonstrating the approach’s potential application, however, scarcity of flight height data prompts further application of the approach to record distributions of flight height. This stereophotogrammetric method was accurate, cost-effective, objective, and relatively simple to apply. It could measure flight heights, and potentially micro-avoidance behaviour in 3-D flight patterns, to ultimately identify species that are at potential risk of collision or burning with wind turbines and solar towers.SUPPORTING INFORMATION:
FIGURE S1. Three-dimensional representation of a sacred ibis flight path in relation to a floodlight (top and side view, respectively). Using the times associated with each set of photographs and the calculated distance between each flight point, the velocity of the bird can be calculated.APPENDIX S1. Trigonometric calculations of the horizontal and vertical area covered by the overlapping fields of view. The maximum measurable flight height was determined for different camera configurations, adjusted for spacing and forward rotation between cameras, and varying distance between the central camera and the focal structure.Tshwane Technology Innovation Agency and Hans Hoheisen Charitable Trust.https://zslpublications.onlinelibrary.wiley.com/journal/14697998hj2022Mammal Research InstituteZoology and Entomolog
Effect of Galectin 3 on Aldosterone-Associated Risk of Cardiovascular Mortality in Patients Undergoing Coronary Angiography
Recent experimental studies have suggested that galectin-3 has an interaction with aldosterone, and modifies its adverse effects. We therefore aimed to elucidate whether the relationship between plasma aldosterone concentrations (PACs) and long-term fatal cardiovascular (CV) events would depend on plasma galectin-3 levels. A total of 2,457 patients (median age: 63.5 [interquartile range (IQR) = 56.3 to 70.6] years, 30.1% women) from the LUdwigshafen RIsk and Cardiovascular Health study, with a median follow-up of 9.9 (IQR = 8.5 to 10.7) years, were included. We tested the interaction between aldosterone and galectin-3 for CV-mortality using a multivariate Cox proportional hazard model, reporting hazard ratios (HRs) with 95% confidence intervals (95%CIs). Adjustments for multiple CV risk factors as well as medication use were included. Mean PAC was 79.0 (IQR = 48.0 to 124.0) pg/ml and there were 558 (16.8%) CV deaths. There was a significant interaction between PAC and galectin-3 (p = 0.021). When stratifying patients by the median galectin-3, there was a significant association between aldosterone and CV-mortality for those above (HR per 1 standard deviation = 1.14; 95%CI [1.01 to 1.30], p = 0.023), but not below the cut-off value (HR per 1 standard deviation = 1.00; 95%CI [0.87 to 1.15], p = 0.185). In conclusion, the current study demonstrates for the first time a modifying effect of galectin-3 on the association between aldosterone and CV-mortality risk in humans. These findings indicate that galectin-3 is an intermediate between aldosterone and adverse outcomes
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