10,076 research outputs found
Microcatheter–Assisted Circumferential Trabeculotomy in Primary Congenital Glaucoma: Long-Term Clinical Outcomes
Purpose: The purpose of this study was to report the long-term efficacy and clinical outcomes of microcatheter-assisted circumferential trabeculotomy (MCT) in children with
primary congenital glaucoma (PCG). Methods: This is a single-center retrospective study including consecutive children with PCG who underwent MCT with > two years follow up. The primary
outcome was surgical success, defined as intraocular pressure (IOP) ≤ 21 mmHg with (qualified) or without (complete) medications, measured at six months, one year, and then annually. Secondary
outcomes were visual acuity (VA), refraction, axial length (AXL), complications, reinterventions, and number of medications. Results: Twelve eyes of ten patients were included. In eight children only
one eye was affected. The mean ± standard deviation (SD) age at surgery was 6.3 ± 4.1 months. The mean postoperative follow-up was 66 ± 35 months. The mean IOP was 34.3 ± 9.6 mmHg preoperatively and 14.6 ± 2.3 mmHg postoperatively at the last visit (p < 0.001). Complete success was achieved at all time points in 10 out of 12 eyes, while 2 eyes had a qualified success. At three years of age, the mean VA of the operated eyes was 0.25 ± 0.12 logMAR, the mean spherical equivalent was −0.78 ± 1.43 diopters, and the mean AXL was 23.78 mm. Transient hyphema was the only complication observed. None of the children required additional glaucoma surgery. Conclusions:
Circumferential trabeculotomy for PCG effectively lowers the IOP at more than two years after surgery. Following this procedure, the prognosis for the visual function is good, and the refractive error is low. Postoperative complications were not significant
A Keplerian gaseous disk around the B0 star R Mon
We present high-angular resolution observations of the circumstellar disk
around the massive Herbig Be star R Mon (M~8 Msun) in the continuum at 2.7mm
and 1.3mm and the CO 1->0 and 2->1 rotational lines. Based on the new 1.3mm
continuum image we estimate a disk mass (gas+dust) of 0.007 Msun and an outer
radius of <150 AU. Our CO images are consistent with the existence of a
Keplerian rotating gaseous disk around this star. Up to our knowledge, this is
the most clear evidence for the existence of Keplerian disks around massive
stars reported thus far. The mass and physical characteristics of this disk are
similar to thoseof the more evolved T Tauri stars and indicate a shorter
timescale for the evolution and dispersal of circumstellar disks around massive
stars which lose most of their mass before the star becomes visible.Comment: 5 page
A Machine Learning-Based Approach for Audio Signals Classification using Chebychev Moments and Mel-Coefficients
This paper proposes a machine learning-based architecture for audio signals classification based on a joint exploitation of the Chebychev moments and the Mel-Frequency Cepstrum Coefficients. The procedure starts with the computation of the Mel-spectrogram of the recorded audio signals; then, Chebychev moments are obtained projecting the Cadence Frequency Diagram derived from the Mel-spectrogram into the base of Chebychev moments. These moments are then concatenated with the Mel-Frequency Cepstrum Coefficients to form the final feature vector. By doing so, the architecture exploits the peculiarities of the discrete Chebychev moments such as their symmetry characteristics. The effectiveness of the procedure is assessed on two challenging datasets, UrbanSound8K and ESC-50
High angular resolution imaging of the circumstellar material around intermediate mass (IM) stars
In this Paper we present high angular resolution imaging of 3
intermediate-mass (IM) stars using the Plateau de Bure Interferometer (PdBI).
In particular we present the chemical study we have carried out towards the IM
hot core NGC 7129--FIRS 2. This is the first chemical study in an IM hot core
and provides important hints to understand the dependence of the hot core
chemistry on the stellar luminosity. We also present our high angular
resolution (0.3") images of the borderline Class 0-Class I object IC1396 N.
These images trace the warm region of this IM protostar with unprecedent detail
(0.3"\sim200 AU at the distance of IC1396 N) and provide the first detection of
a cluster of IM hot cores. Finally, we present our interferometric continuum
and spectroscopic images of the disk around the Herbig Be star R Mon. We have
determined the kinematics and physical structure of the disk associated with
this B0 star. The low spectral index derived from the dust emission as well as
the flat geometry of the disk suggest a more rapid evolution of the disks
associated with massive stars. In the Discussion, we dare to propose a possible
evolutionary sequence for the warm circumstellar material around IM stars.Comment: 4 pages, 2 figures. Proceedings of the conference "Science with ALMA:
a new era for Astrophysics" hold in Madrid in November, 13-17, 200
Modelling the Molecular Gas in NGC 6240
We present the first observations of HCN, HCO
and SiO in NGC\,6240, obtained with the IRAM PdBI. Combining a Markov
Chain Monte Carlo (MCMC) code with Large Velocity Gradient (LVG) modelling, and
with additional data from the literature, we simultaneously fit three gas
phases and six molecular species to constrain the physical condition of the
molecular gas, including massluminosity conversion factors. We find
of dense molecular gas in cold, dense clouds (\,K, \,cm) with a volume filling factor
, embedded in a shock heated molecular medium (\,K,
\,cm), both surrounded by an extended diffuse
phase (\,K, \,cm). We
derive a global with gas masses
, dominated by the
dense gas. We also find , which traces the
cold, dense gas. The [C]/[C] ratio is only slightly elevated
(), contrary to the very high [CO]/[CO] ratio (300-500)
reported in the literature. However, we find very high [HCN]/[HCN] and
[HCO]/[HCO] abundance ratios which we
attribute to isotope fractionation in the cold, dense clouds.Comment: 27 pages, 17 figures, 9 tables. Accepted in Ap
Electromagnetic dipole moments of charged baryons with bent crystals at the LHC
We propose a unique program of measurements of electric and magnetic dipole
moments of charm, beauty and strange charged baryons at the LHC, based on the
phenomenon of spin precession of channeled particles in bent crystals. Studies
of crystal channeling and spin precession of positively- and negatively-charged
particles are presented, along with feasibility studies and expected
sensitivities for the proposed experiment using a layout based on the LHCb
detector.Comment: 19 pages, 13 figure
First evidence for dusty disks around Herbig Be stars
We have carried out a high-sensitivity search for circumstellar disks around
Herbig Be stars in the continuum at 1.4mm and 2.7mm using the IRAM
interferometer at the Plateau de Bure (PdBI) . In this letter, we report data
on three well studied B0 stars, MWC 1080, MWC 137 and R Mon. The two latter
have also been observed in the continuum at 0.7 cm and 1.3 cm using the NRAO
Very Large Array (VLA) . We report the detection of circumstellar disks around
MWC 1080 and R Mon with masses of Md ~ 0.003 and 0.01 Msun, respectively, while
for MWC 137 we estimate a disk mass upper limit of 0.007 Msun. Our results show
that the ratio Md/M* is at least an order of magnitude lower in Herbig Be stars
than in Herbig Ae and T Tauri stars.Comment: 5 pages (including figures
Automated Experimental Modal Analysis of Bladed Wheels with an Anthropomorphic Robotic Station
Experimental modal analysis is challenging when the component has a highly three-dimensional shape, since a great number of measurement points are needed with accurate positioning. An anthropomorphic robotic station is proposed to automate this analysis, specifically on bladed wheels. This provides a reliable control of the spot location and of the beam orientation of a Laser Doppler Vibrometer. The modal frequencies were obtained along with the vibrational shapes and their spatial resolution was managed by exploiting the programming flexibility of the robotic station. The SAFE diagram was easily obtained by measuring a single point for each sector, and an extension of this diagram was demonstrated for the splitter blade wheels. The use of multiple measurement points, for each wheel sector, significantly improved the characterization of the modes having the same number of nodal diameters, hence the same shape coordinate on the SAFE diagram
Feeding AGN: new results from the NUGA survey
The NUGA project is a high-resolution (0.5''-1'') CO survey of low luminosity
AGN including the full sequence of activity types (Seyferts, LINERs and
transition objects). NUGA aims to systematically study the different mechanisms
for gas fueling of AGNs in the Local Universe. In this paper we discuss the
latest results of this recently completed survey, which now includes newly
acquired subarcsec resolution observations for all targets of the sample. The
large variety of circumnuclear disk morphologies found in NUGA galaxies (m=1,
m=2 and stochastic instabilities) is a challenging result that urges the
refinement of current dynamical models. In this paper we report on new results
obtained in 4 study cases for NUGA: NGC4826, NGC7217, NGC4579 and NGC6951Comment: 4 pages, 2 figures. Contributed talk to appear in "The Interplay
among Black Holes, Stars and ISM in Galactic Nuclei," Proc. IAU 222 (Gramado,
Brazil), eds. Th. Storchi Bergmann, L.C. Ho, H.R. Schmit
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