716 research outputs found
Cogan's syndrome: clinical evolution of deafness and vertigo in three patients
The aim of this study was to evaluate the clinical symptoms, the otoneurological examinations, the treatment and the clinical course of three patients suffering from Cogan's syndrome, a rare disease based on the clinical association of a non-syphilitic interstitial keratitis with a cochleo-vestibular deficit. This case series involved three patients with follow up. The clinical course of the three patients (aged 30, 48 and 49years) with Cogan's syndrome during a follow-up period of 2 to 6years is reported. All patients underwent complete otoneurological, ophthalmologic and rheumatologic examinations and were treated with immunosuppressive therapy such as glucocorticoids and cyclophosphamide in two and glucocorticoids and methotrexate in one patient. Using immunosuppressive therapy, ophthalmologic symptoms disappeared rapidly in two patients. Hearing improved only in one and stabilized in a second patient. One patient died after 6years of treatment because of complications of generalized vasculitis. Early diagnosis and rapid initiation of a combined immunosuppressive therapy such as corticosteroids and cyclophosphamide seem to be important in controlling the disease and avoiding persistent deafness. Whether systemic complications and a fatal outcome also can be prevented is still questionabl
Photometry in UV astronomical images of extended sources in crowded field using deblended images in optical visible bands as Bayesian priors
Photometry of astrophysical sources, galaxies and stars, in crowded field images, if an old problem, is still a challenging goal, as new space survey missions are launched, releasing new data with increased sensibility, resolution and field of view. The GALEX mission, observes in two UV bands and produces deep sky images of millions of galaxies or stars mixed together. These UV observations are of lower resolution than same field observed in visible bands, and with a very faint signal, at the level of the photon noise for a substantial fraction of objects. Our purpose is to use the better known optical counterparts as prior information in a Bayesian approach to deduce the UV flux. Photometry of extended sources has been addressed several times using various techniques: background determination via sigma clipping, adaptative-aperture, point-spread-function photometry, isophotal photometry, to lists some. The Bayesian approach of using optical priors for solving the UV photometry has already been applied by our team in a previous work. Here we describe the improvement of using the extended shape inferred by deblending the high resolution optical images and not only the position of the optical sources. The resulting photometric accuracy has been tested with simulation of crowded UV fields added on top of real UV images. Finally, this helps to converge to smaller and flat residual and increase the faint source detection threshold. It thus gives the opportunity to work on 2nd order effects, like improving the knowledge of the background or point-spread function by iterating on them
The VIPERS Multi-Lambda Survey. I. UV and NIR Observations, multi-color catalogues and photometric redshifts
We present observations collected in the CFHTLS-VIPERS region in the
ultraviolet (UV) with the GALEX satellite (far and near UV channels) and the
near infrared with the CFHT/WIRCam camera (-band) over an area of 22 and
27 deg, respectively. The depth of the photometry was optimized to measure
the physical properties (e.g., SFR, stellar masses) of all the galaxies in the
VIPERS spectroscopic survey. The large volume explored by VIPERS will enable a
unique investigation of the relationship between the galaxy properties and
their environment (density field and cosmic web) at high redshift (0.5 < z <
1.2). In this paper, we present the observations, the data reductions and the
build-up of the multi-color catalogues. The CFHTLS-T0007 (gri-{\chi}^2) images
are used as reference to detect and measure the -band photometry, while
the T0007 u-selected sources are used as priors to perform the GALEX photometry
based on a dedicated software (EMphot). Our final sample reaches ~25
(at 5{\sigma}) and ~22 (at 3{\sigma}). The large spectroscopic sample
(~51,000 spectroscopic redshifts) allows us to highlight the robustness of our
star/galaxy separation, and the reliability of our photometric redshifts with a
typical accuracy 0.04 and a catastrophic failure rate {\eta} <
2% down to i~23. We present various tests on the band completeness and
photometric redshift accuracy by comparing with existing, overlapping deep
photometric catalogues. Finally, we discuss the BzK sample of passive and
active galaxies at high redshift and the evolution of galaxy morphology in the
(NUV-r) vs (r-K_s) diagram at low redshift (z < 0.25) thanks to the high image
quality of the CFHTLS. The images, catalogues and photometric redshifts for 1.5
million sources (down to 25 or 22) are released and
available at this URL: http://cesam.lam.fr/vipers-mls/Comment: 14 pages, 16 figures. Accepted for publication in A&A. Version to be
publishe
Resveratrol Decreases TXNIP mRNA and Protein Nuclear Expressions With an Arterial Function Improvement in Old Mice
Aging leads to a high prevalence of glucose intolerance and cardiovascular diseases, with oxidative stress playing a potential role. Resveratrol has shown promising effects on glucose tolerance and tends to improve endothelial function in elderly patients. Thioredoxin-interacting protein (TXNIP) was recently proposed as a potential link connecting glucose metabolism to oxidative stress. Here, we investigated the resveratrol-induced improvement of arterial aging phenotype in old mice and the expression of aortic TXNIP. Using an in vivo model of old mice with or without 3-month resveratrol treatment, we investigated the effects of resveratrol on age-related impairments from a cardiovascular Doppler analysis, to a molecular level, by studying inflammation and oxidative stress factors. We found a dual effect of resveratrol, with a decrease of age-related glucose intolerance and oxidative stress imbalance leading to reduced matrix remodeling that forestalls arterial aging phenotype in terms of intima-media thickness and arterial distensibility. These results provide the first evidence that aortic TXNIP mRNA and protein nuclear expressions are increased in the arterial aging and decreased by resveratrol treatment. In conclusion, we demonstrated that resveratrol helped to restore several aging impaired processes in old mice, with a decrease of aortic TXNIP mRNA and protein nuclear expression
An Ishihara-style test of animal colour vision
ABSTRACT Colour vision mediates ecologically relevant tasks for many animals, such as mate choice, foraging and predator avoidance. However, our understanding of animal colour perception is largely derived from human psychophysics, and behavioural tests of non-human animals are required to understand how colour signals are perceived. Here, we introduce a novel test of colour vision in animals inspired by the Ishihara colour charts, which are widely used to identify human colour deficiencies. In our method, distractor dots have a fixed chromaticity (hue and saturation) but vary in luminance. Animals can be trained to find single target dots that differ from distractor dots in chromaticity. We provide MATLAB code for creating these stimuli, which can be modified for use with different animals. We demonstrate the success of this method with triggerfish, Rhinecanthus aculeatus, which quickly learnt to select target dots that differed from distractor dots, and highlight behavioural parameters that can be measured, including success of finding the target dot, time to detection and error rate. We calculated discrimination thresholds by testing whether target colours that were of increasing colour distances (ΔS) from distractor dots could be detected, and calculated discrimination thresholds in different directions of colour space. At least for some colours, thresholds indicated better discrimination than expected from the receptor noise limited (RNL) model assuming 5% Weber fraction for the long-wavelength cone. This methodology could be used with other animals to address questions such as luminance thresholds, sensory bias, effects of sensory noise, colour categorization and saliency
Surgical capping of superior semicircular canal dehiscence
Surgical plugging and resurfacing are well established treatments of superior semicircular canal dehiscence, while capping with hydroxyapatite cement has been little discussed in literature. The aim of this study was to prove the efficacy of the capping technique. Charts of patients diagnosed with superior semicircular canal dehiscence were reviewed retrospectively. All patients answered the dizziness handicap inventory, a survey analyzing the impact of their symptoms on their quality of life. Capping of the dehiscent canal was performed via the middle fossa approach in all cases. Ten out of 22 patients diagnosed with superior semicircular canal dehiscence were treated with surgical capping, nine of which were included in this study. No major perioperative complications occurred. In 8 out of 9 (89%) patients, capping led to a satisfying reduction of the main symptoms. One patient underwent revision surgery 1year after the initial intervention. Scores in the dizziness handicap inventory were lower in the surgically treated group than in the non-surgically treated group, but results were not statistically significant (P=0.45). Overall, capping is a safe and efficient alternative to plugging and resurfacing of superior semicircular canal dehiscence
Automated reliability assessment for spectroscopic redshift measurements
We present a new approach to automate the spectroscopic redshift reliability
assessment based on machine learning (ML) and characteristics of the redshift
probability density function (PDF).
We propose to rephrase the spectroscopic redshift estimation into a Bayesian
framework, in order to incorporate all sources of information and uncertainties
related to the redshift estimation process, and produce a redshift posterior
PDF that will be the starting-point for ML algorithms to provide an automated
assessment of a redshift reliability.
As a use case, public data from the VIMOS VLT Deep Survey is exploited to
present and test this new methodology. We first tried to reproduce the existing
reliability flags using supervised classification to describe different types
of redshift PDFs, but due to the subjective definition of these flags, soon
opted for a new homogeneous partitioning of the data into distinct clusters via
unsupervised classification. After assessing the accuracy of the new clusters
via resubstitution and test predictions, unlabelled data from preliminary mock
simulations for the Euclid space mission are projected into this mapping to
predict their redshift reliability labels.Comment: Submitted on 02 June 2017 (v1). Revised on 08 September 2017 (v2).
Latest version 28 September 2017 (this version v3
Observable Signatures of the low-z Circum-Galactic and Inter-Galactic Medium : UV Line Emission in Simulations
We present for the first time predictions for UV line emission of
intergalactic and circumgalactic gas from Adaptive Mesh Resolution (AMR) Large
Scale Structure (LSS) simulations at redshifts 0.3<z<1.2, with specific
emphasis on observability with current and near-future UV instrumentation. In
three transitions of interest (Lya, OVI and CIV) there is a clear bimodality in
the type of objects : the overwhelming majority of flux stems from discrete,
compact sources, while a much larger volume fraction is filled by more tenuous
gas. We characterise both object types with regard to number density, physical
size and shape, brightness, luminosity, velocity structure, mass, temperature,
ionisation state, and metal content. Degrading AMR grids to characteristic
resolutions of available (such as FIREBall) or foreseeable instrumentation,
allows to assess which inferences can be drawn from currently possible
observations, and set foundations to prepare observing strategies for future
missions. In general, the faint emission of the IGM and filamentary structure
remains beyond capabilities of instruments with only short duration exposure
potential (stratospheric balloons), even for optimistic assumptions for Lya,
while the yet fainter metal line transitions for these structures will remain
challenging for long duration exposures (space-based telescopes), mostly due to
low metallicity pushing them more than three orders of magnitudes in brightness
below Lya radiation. For the circum-galactic medium (CGM) the situation is more
promising, and it is foreseeable that in the near future we will not only just
dectect such sources, but the combination of all three lines in addition to
velocity information will yield valuable insight into the physical processes at
hand, illuminating important mechanisms during the formation of galaxies and
their backreaction onto the IGM from whence they formed. (abrigded)Comment: Accepted for publication in MNRAS (2011 November 08, received in
original form 2011 September 14). 27 pages, 19 figures, 3 tables. Some of the
figures have degraded resolution due to file size limitations. For
high-resolution version, please contact the first autho
Slider-Block Friction Model for Landslides: Application to Vaiont and La Clapiere Landslides
Accelerating displacements preceding some catastrophic landslides have been
found empirically to follow a time-to-failure power law, corresponding to a
finite-time singularity of the velocity [{\it Voight},
1988]. Here, we provide a physical basis for this phenomenological law based on
a slider-block model using a state and velocity dependent friction law
established in the laboratory and used to model earthquake friction. This
physical model accounts for and generalizes Voight's observation: depending on
the ratio of two parameters of the rate and state friction law and on the
initial frictional state of the sliding surfaces characterized by a reduced
parameter , four possible regimes are found. Two regimes can account for
an acceleration of the displacement. We use the slider-block friction model to
analyze quantitatively the displacement and velocity data preceding two
landslides, Vaiont and La Clapi\`ere. The Vaiont landslide was the catastrophic
culmination of an accelerated slope velocity. La Clapi\`ere landslide was
characterized by a peak of slope acceleration that followed decades of ongoing
accelerating displacements, succeeded by a restabilizing phase. Our inversion
of the slider-block model on these data sets shows good fits and suggest to
classify the Vaiont (respectively La Clapi\`ere) landslide as belonging to the
velocity weakening unstable (respectively strengthening stable) sliding regime.Comment: shortened by focusing of the frictional model, Latex document with
AGU style file of 14 pages + 11 figures (1 jpeg photo of figure 6 given
separately) + 1 tabl
High-protein-low-carbohydrate diet: deleterious metabolic and cardiovascular effects depend on age
High-protein-low-carbohydrate (HP-LC) diets have become widespread. Yet their deleterious consequences, especially on glucose metabolism and arteries, have already been underlined. Our previous study (2) has already shown glucose intolerance with major arterial dysfunction in very old mice subjected to an HP-LC diet. The hypothesis of this work was that this diet had an age-dependent deleterious metabolic and cardiovascular outcome. Two groups of mice, young and adult (3 and 6 mo old), were subjected for 12 wk to a standard or to an HP-LC diet. Glucose and lipid metabolism was studied. The cardiovascular system was explored from the functional stage with Doppler-echography to the molecular stage (arterial reactivity, mRNA, immunohistochemistry). Young mice did not exhibit any significant metabolic modification, whereas adult mice presented marked glucose intolerance associated with an increase in resistin and triglyceride levels. These metabolic disturbances were responsible for cardiovascular damages only in adult mice, with decreased aortic distensibility and left ventricle dysfunction. These seemed to be the consequence of arterial dysfunctions. Mesenteric arteries were the worst affected with a major oxidative stress, whereas aorta function seemed to be maintained with an appreciable role of cyclooxygenase-2 to preserve endothelial function. This study highlights for the first time the age-dependent deleterious effects of an HP-LC diet on metabolism, with glucose intolerance and lipid disorders and vascular (especially microvessels) and cardiac functions. This work shows that HP-LC lead to equivalent cardiovascular alterations, as observed in very old age, and underlines the danger of such diet
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