4,119 research outputs found

    The SPHERE data center: a reference for high contrast imaging processing

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    The objective of the SPHERE Data Center is to optimize the scientific return of SPHERE at the VLT, by providing optimized reduction procedures, services to users and publicly available reduced data. This paper describes our motivation, the implementation of the service (partners, infrastructure and developments), services, description of the on-line data, and future developments. The SPHERE Data Center is operational and has already provided reduced data with a good reactivity to many observers. The first public reduced data have been made available in 2017. The SPHERE Data Center is gathering a strong expertise on SPHERE data and is in a very good position to propose new reduced data in the future, as well as improved reduction procedures.Comment: SF2A proceeding

    Preserving normal facial nerve function and improving hearing outcome in large vestibular schwannomas with a combined approach: planned subtotal resection followed by gamma knife radiosurgery.

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    To perform planned subtotal resection followed by gamma knife surgery (GKRS) in a series of patients with large vestibular schwannoma (VS), aiming at an optimal functional outcome for facial and cochlear nerves. Patient characteristics, surgical and dosimetric features, and outcome were collected prospectively at the time of treatment and during the follow-up. A consecutive series of 32 patients was treated between July 2010 and June 2016. Mean follow-up after surgery was 29 months (median 24, range 4-78). Mean presurgical tumor volume was 12.5 cm3 (range 1.47-34.9). Postoperative status showed normal facial nerve function (House-Brackmann I) in all patients. In a subgroup of 17 patients with serviceable hearing before surgery and in which cochlear nerve preservation was attempted at surgery, 16 (94.1%) retained serviceable hearing. Among them, 13 had normal hearing (Gardner-Robertson class 1) before surgery, and 10 (76.9%) retained normal hearing after surgery. Mean duration between surgery and GKRS was 6.3 months (range 3.8-13.9). Mean tumor volume at GKRS was 3.5 cm3 (range 0.5-12.8), corresponding to mean residual volume of 29.4% (range 6-46.7) of the preoperative volume. Mean marginal dose was 12 Gy (range 11-12). Mean follow-up after GKRS was 24 months (range 3-60). Following GKRS, there were no new neurological deficits, with facial and hearing functions remaining identical to those after surgery in all patients. Three patients presented with continuous growth after GKRS, were considered failures, and benefited from the same combined approach a second time. Our data suggest that large VS management, with planned subtotal resection followed by GKRS, might yield an excellent clinical outcome, allowing the normal facial nerve and a high level of cochlear nerve functions to be retained. Our functional results with this approach in large VS are comparable with those obtained with GKRS alone in small- and medium-sized VS. Longer term follow-up is necessary to fully evaluate this approach, especially regarding tumor control

    Prevalence and management of chronic insomnia in Swiss primary care: Cross-sectional data from the “Sentinella” practice-based research network

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    We investigated the prevalence and treatment of patients with chronic insomnia presenting to Swiss primary care physicians (PCPs) part of “Sentinella”, a nationwide practice-based research network. Each PCP consecutively asked 40 patients if they had sleep complaints, documented frequency, duration, comorbidities, and reported ongoing treatment. We analysed data of 63% (83/132) of the PCPs invited. The PCPs asked 76% (2,432/3,216) of included patients about their sleep (51% female); 31% (761/2,432) of these had had insomnia symptoms; 36% (875/2,432) had current insomnia symptoms; 11% (269/2,432) met the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria for chronic insomnia (61% female). In all, 75% (201/269) of patients with chronic insomnia had comorbidities, with 49% (99/201) reporting depression. Chronic insomnia was treated in 78% (209/269); 70% (188/268) took medication, 38% (102/268) benzodiazepines or benzodiazepine receptor agonists, 32% (86/268) took antidepressants. Only 1% (three of 268) had been treated with cognitive behavioural therapy for insomnia (CBT-I). A third of patients presenting for a non-urgent visit in Swiss primary care reported insomnia symptoms and 11% met the DSM-5 criteria for chronic insomnia. Hypnotics were the most common treatment, but almost no patients received first-line CBT-I. Reducing the burden of insomnia depends on disseminating knowledge about and access to CBT-I, and encouraging PCPs to discuss it with and offer it as a first-line treatment to patients with chronic insomnia

    Treating insomnia in Swiss primary care practices: A survey study based on case vignettes

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    Guidelines recommend cognitive behavioural therapy for insomnia (CBT-I) as first-line treatment for chronic insomnia, but it is not clear how many primary care physicians (PCPs) in Switzerland prescribe this treatment. We created a survey that asked PCPs how they would treat chronic insomnia and how much they knew about CBT-I. The survey included two case vignettes that described patients with chronic insomnia, one with and one without comorbid depression. PCPs also answered general questions about treating chronic insomnia and about CBT-I and CBT-I providers. Of the 820 Swiss PCPs we invited, 395 (48%) completed the survey (mean age 54 years; 70% male); 87% of PCPs prescribed sleep hygiene and 65% phytopharmaceuticals for the patient who had only chronic insomnia; 95% prescribed antidepressants for the patient who had comorbid depression. In each case, 20% of PCPs prescribed benzodiazepines or benzodiazepine receptor agonists, 8% prescribed CBT-I, 68% said they knew little about CBT-I, and 78% did not know a CBT-I provider. In the clinical case vignettes, most PCPs treated chronic insomnia with phytopharmaceuticals and sleep hygiene despite their lack of efficacy, but PCPs rarely prescribed CBT-I, felt they knew little about it, and usually knew no CBT-I providers. PCPs need more information about the benefits of CBT-I and local CBT-I providers and dedicated initiatives to implement CBT-I in order to reduce the number of patients who are prescribed ineffective or potentially harmful medications

    ArDM: first results from underground commissioning

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    The Argon Dark Matter experiment is a ton-scale double phase argon Time Projection Chamber designed for direct Dark Matter searches. It combines the detection of scintillation light together with the ionisation charge in order to discriminate the background (electron recoils) from the WIMP signals (nuclear recoils). After a successful operation on surface at CERN, the detector was recently installed in the underground Laboratorio Subterr\'aneo de Canfranc, and the commissioning phase is ongoing. We describe the status of the installation and present first results from data collected underground with the detector filled with gas argon at room temperature.Comment: 6 pages, 3 figures, Light Detection In Noble Elements (LIDINE 2013

    Shadows cast on the transition disk of HD 135344B. Multiwavelength VLT/SPHERE polarimetric differential imaging

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    The protoplanetary disk around the F-type star HD 135344B (SAO 206462) is in a transition stage and shows many intriguing structures both in scattered light and thermal (sub-)millimeter emission which are possibly related to planet formation processes. We study the morphology and surface brightness of the disk in scattered light to gain insight into the innermost disk regions, the formation of protoplanets, planet-disk interactions traced in the surface and midplane layers, and the dust grain properties of the disk surface. We have carried out high-contrast polarimetric differential imaging (PDI) observations with VLT/SPHERE and obtained polarized scattered light images with ZIMPOL in R- and I-band and with IRDIS in Y- and J-band. The scattered light images reveal with unprecedented angular resolution and sensitivity the spiral arms as well as the 25 au cavity of the disk. Multiple shadow features are discovered on the outer disk with one shadow only being present during the second observation epoch. A positive surface brightness gradient is observed in the stellar irradiation corrected images in southwest direction possibly due to an azimuthally asymmetric perturbation of the temperature and/or surface density by the passing spiral arms. The disk integrated polarized flux, normalized to the stellar flux, shows a positive trend towards longer wavelengths which we attribute to large aggregate dust grains in the disk surface. Part of the the non-azimuthal polarization signal in the Uphi image of the J-band observation could be the result of multiple scattering in the disk. The detected shadow features and their possible variability have the potential to provide insight into the structure of and processes occurring in the innermost disk regions.Comment: Accepted for publication in A&A, 20 pages, 15 figure

    Status of the ArDM Experiment: First results from gaseous argon operation in deep underground environment

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    The Argon Dark Matter (ArDM-1t) experiment is a ton-scale liquid argon (LAr) double-phase time projection chamber designed for direct Dark Matter searches. Such a device allows to explore the low energy frontier in LAr. After successful operation on surface at CERN, the detector has been deployed underground and is presently commissioned at the Canfranc Underground Laboratory (LSC). In this paper, we describe the status of the installation and present first results on data collected in gas phase.Comment: 21 pages, 20 figure

    A narrow, edge-on disk resolved around HD 106906 with SPHERE

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    HD~106906AB is so far the only young binary system around which a planet has been imaged and a debris disk evidenced thanks to a strong IR excess. As such, it represents a unique opportunity to study the dynamics of young planetary systems. We aim at further investigating the close (tens of au scales) environment of the HD~106906AB system. We used the extreme AO fed, high contrast imager SPHERE recently installed on the VLT to observe HD~106906. Both the IRDIS imager and the Integral Field Spectrometer were used. We discovered a very inclined, ring-like disk at a distance of 65~au from the star. The disk shows a strong brightness asymmetry with respect to its semi-major axis. It shows a smooth outer edge, compatible with ejection of small grains by the stellar radiation pressure. We show furthermore that the planet's projected position is significantly above the disk's PA. Given the determined disk inclination, it is not excluded though that the planet could still orbit within the disk plane if at a large separation (2000--3000 au). We identified several additional point sources in the SPHERE/IRDIS field-of-view, that appear to be background objects. We compare this system with other debris disks sharing similarities, and we briefly discuss the present results in the framework of dynamical evolution.Comment: 7 pages, 6 figures, accepted by Astronomy & Astrophysic
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