649 research outputs found

    Cogan's syndrome: clinical evolution of deafness and vertigo in three patients

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    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

    FIREBALL: Detector, data acquisition and reduction

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    The Faint Intergalactic Redshifted Emission Balloon (FIREBALL) had its first scientific flight in June 2009. The instrument combines microchannel plate detector technology with fiber-fed integral field spectroscopy on an unstable stratospheric balloon gondola platform. This unique combination poses a series of calibration and data reduction challenges that must be addressed and resolved to allow for accurate data analysis. We discuss our approach and some of the methods we are employing to accomplish this task

    Photometry in UV astronomical images of extended sources in crowded field using deblended images in optical visible bands as Bayesian priors

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    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

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    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 (KsK_s-band) over an area of 22 and 27 deg2^2, 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 KsK_s-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 NUVABNUV_{AB}~25 (at 5{\sigma}) and KABK_{AB}~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 σz≀\sigma_z \le 0.04 and a catastrophic failure rate {\eta} < 2% down to i~23. We present various tests on the KsK_s 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 NUV≀NUV \le 25 or Ks≀K_s \le 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

    Observable Signatures of the low-z Circum-Galactic and Inter-Galactic Medium : UV Line Emission in Simulations

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    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

    Resveratrol Decreases TXNIP mRNA and Protein Nuclear Expressions With an Arterial Function Improvement in Old Mice

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    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

    Surgical capping of superior semicircular canal dehiscence

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    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

    MAPCUMBA : a fast iterative multi-grid map-making algorithm for CMB experiments

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    The data analysis of current Cosmic Microwave Background (CMB) experiments like BOOMERanG or MAXIMA poses severe challenges which already stretch the limits of current (super-) computer capabilities, if brute force methods are used. In this paper we present a practical solution to the optimal map making problem which can be used directly for next generation CMB experiments like ARCHEOPS and TopHat, and can probably be extended relatively easily to the full PLANCK case. This solution is based on an iterative multi-grid Jacobi algorithm which is both fast and memory sparing. Indeed, if there are N_tod data points along the one dimensional timeline to analyse, the number of operations is O(N_tod ln N_tod) and the memory requirement is O(N_tod). Timing and accuracy issues have been analysed on simulated ARCHEOPS and TopHat data, and we discuss as well the issue of the joint evaluation of the signal and noise statistical properties.Comment: 10 pages, 8 postscript and 3 jpeg figures. Submitted to AA. Code available at http://ulysse.iap.fr/download/mapcumba

    Automated reliability assessment for spectroscopic redshift measurements

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    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

    Slider-Block Friction Model for Landslides: Application to Vaiont and La Clapiere Landslides

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    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 v∌1/(tc−t)v \sim 1/(t_c-t) [{\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 B/AB/A 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 xix_i, 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
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