3,727 research outputs found

    Sensitivity and spatial resolution of square loop SQUID magnetometers

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    We calculate the flux threading the pick-up coil of a square SQUID magnetometer in the presence of a current dipole source. The result reproduces that of a circle coil magnetometer calculated by Wikswo with only small differences. However it has a simpler form so that it is possible to derive from it closed form expressions for the current dipole sensitivity and the spatial resolution. The results are useful to assess the overall performance of the device and to compare different designs

    Grapevine death caused by Nattrassia toruloidea

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    Severe decline has been observed on different grapevine cultivars (Vitis vinifera L.) grafted on rootstock hybrid 140 R.(V. berlandieri PLANCHON x V. rupestris SCHEELE) in various plantations in eastern and central Sicily. The affected grapevines presented chlorotic leaf spots and necrosis. Early leaf cast was followed by drying of the shoots from the apex and darkening of subcortical tissues. The whole grapevine died 2 or 3 years after onset of leaf symptoms. The fungus Nattrassia toruloidea (NATTRASS) DYKO and SUTTON was constantly isolated from the infected wood. Artificial inoculation of the isolate on rooted cuttings of the local cultivars Nerello Mascalese and Frappato di Vittoria reproduced the disease observed in the field. The fungus was reisolated from the artificially inoculated plants, confirming that N. toruloidea is the specific pathogenic agent responsible for the grapevine death observed by us. The most suitable temperature range for growth of this pathogen is 30-35°C which explains its distribution in hot African and Asian countries, its presence in Sicily and its widespread diffusion during the summer season

    TASTE IV. Refining ephemeris and orbital parameters for HAT-P-20b and WASP-1b

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    We present four new light curves of transiting exoplanets WASP-1b and HAT-P-20b, observed within the TASTE (The Asiago Search for Transit timing variations of Exoplanets) project. We re-analyzed light curves from the literature in a homogeneous way, calculating a refined ephemeris and orbital-physical parameters for both objects. WASP-1b does not show any significant Transit Timing Variation signal at the 120 s-level. As for HAT-P-20b, we detected a deviation from our re-estimated linear ephemeris that could be ascribed to the presence of a perturber or, more probably, to a previously unnoticed high level of stellar activity. The rotational period of HAT-P-20 A we obtained from archival data (P_rot ~ 14.5 days), combined with its optical variability and strong emission of CaII H&K lines, is consistent with a young stellar age (< 1 Gyr) and support the hypothesis that stellar activity may be responsible of the measured deviations of the transit times.Comment: 7 pages, 4 figures, 3 tables, accepted to Astronomische Nachrichte

    Variable stars in one open cluster within the Kepler/K2-Campaign-5 field: M 67 (NGC 2682)

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    In this paper we continue the release of high-level data products from the multiyear photometric survey collected at the 67/92 cm Schmidt Telescope in Asiago. The primary goal of the survey is to discover and to characterise variable objects and exoplanetary transits in four fields containing five nearby open clusters spanning a broad range of ages. This second paper releases a photometric catalogue, in five photometric bands, of the Solar-age, Solar-metallicity open cluster M 67 (NGC 2682). Proper motions are derived comparing the positions observed in 2013 at the Asiago's Schmidt Telescope with those extracted from [email protected] MPG/ESO images in 2000. We also analyse the variable sources within M 67. We detected 68 variables, 43 of which are new detection. Variable periods and proper-motion memberships of a large majority of sources in our catalogue are improved with respect to previous releases. The entire catalogue will be available in electronic format. Besides the general interest on an improved catalogue, this work will be particularly useful because of: (1) the imminent release of Kepler/K2 Campaign-5 data of this cluster, for which our catalogue will provide an excellent, high spatial resolution input list, and (2) characterisation of the M 67 stars which are targets of intense HARPS and HARPS-N radial-velocity surveys for planet search.Comment: 8 pages, 6 figures (2 at low resolution), 2 tables. Accepted for publication in MNRAS on October 17, 2015. Electronic materials available at the url http://groups.dfa.unipd.it/ESPG/M67.html , and later on the Journal and at the CD

    The BeppoSAX WFC X-ray source catalogue

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    We present the catalogue of X-ray sources detected by the two Wide Field Cameras (WFCs) in complete observations on board BeppoSAX during its 6 years of operational lifetime, between April 1996 and April 2002. The BeppoSAX WFCs were coded mask instruments sensitive in the 2-28 keV energy band with a 40x40 square degree fields of view, pointing in opposite directions and perpendicularly to the BeppoSAX Narrow Field Instruments (NFI). The WFCs were usually operated simultaneously to NFI observations, each lasting up to several days. WFCs observed thus the entire sky several times with a typical sensitivity of 2 to 10 mCrab. A systematic analysis of all WFC observations in the BeppoSAX archive has been carried out using the latest post-mission release of the WFC analysis software and calibrations. The catalogue includes 253 distinct sources, obtained from a total sample of 8253 WFC detections. We describe the basic statistical properties of the sample and present a six-year history of two celestial calibration X-ray sources.Comment: 15 pages, 11 figures, Catalogue, Accepted for publication on A&

    Hylan G-F 20: Review of its Safety and Efficacy in the Management of Joint Pain in Osteoarthritis

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    BACKGROUND: Osteoarthritis (OA) is a chronic degenerative joint disease that is a clinically and economically important disease. The increased prevalence of OA with aging, coupled to the demographics of aging populations, make OA a high priority health care problem. Viscosupplementation (VS) is a well-established treatment option in knee OA that is included in the professional guidelines for treatment of this joint disease, and could potentially provide a useful alternative in treating such patients with painful OA. Theoretically VS is an approach that should apply to all synovial joints. OBJECTIVES: The aim of this review is to assess the efficacy and safety of viscosupplementation with Hylan GF-20 (Synvisc(®)) in the management of joint pain in osteoarthritis. METHODS: THE FOLLOWING DATABASES WERE SEARCHED: Medline, Database of Abstract on Reviews and Effectiveness, Cochrane Database of Systematic Reviews. Furthermore, the lists of references of retrieved publications were manually checked for additional references. The search terms Review, Viscosupplementation, Osteoarthritis, Hyaluronic acid, Hyaluronan, Sodium Hyaluronate, Hylan GF-20, Synvisc, intra-articular injection were used to identify all studies relating to the use of Synvisc(®) viscosupplementation therapy in OA. RESULTS: Hylan GF-20 is a safe and effective treatment for decreasing pain and improving function in patients suffering from knee and hip OA but new evidences are emerging for its use in other joints
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