2,075 research outputs found

    Deep 1.4 GHZ Follow Up of the Steep Spectrum Radio Halo in Abell 521

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    In a recent paper we reported on the discovery of a radio halo with very steep spectrum in the merging galaxy cluster Abell 521 through observations with the Giant Metrewave Radio Telescope (GMRT). We showed that the steep spectrum of the halo is inconsistent with a secondary origin of the relativistic electrons and supports a turbulent acceleration scenario. At that time, due to the steep spectrum, the available observations at 1.4 GHz (archival NRAO - Very Large Array - VLA CnB-configuration data) were not adequate to accurately determine the flux density associated with the radio halo. In this paper we report the detection at 1.4 GHz of the radio halo in Abell 521 using deep VLA observations in the D-configuration. We use these new data to confirm the steep-spectrum of the object. We consider Abell 521 the prototype of a population of very-steep spectrum halos. This population is predicted assuming that turbulence plays an important role in the acceleration of relativistic particles in galaxy clusters, and we expect it will be unveiled by future surveys at low frequencies with the LOFAR and LWA radio telescopes.Comment: 11 pages, 3 figures (figure 1 available in gif format only). Requires aastex.cls - Accepted by Ap.

    A KAT-7 view of a low-mass sample of galaxy clusters

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    Radio observations over the last two decades have provided evidence that diffuse synchrotron emission in the form of megaparsec-scale radio halos in galaxy clusters is likely tracing regions of the intracluster medium where relativistic particles are accelerated during cluster mergers. In this paper we present results of a survey of 14 galaxy clusters carried out with the 7-element Karoo Array Telescope at 1.86 GHz, aimed to extend the current studies of radio halo occurrence to systems with lower masses (M500>4×1014_{\rm 500} > 4\times10^{14} M{_\odot}). We found upper limits at the 0.61.9×10240.6 - 1.9 \times 10^{24} Watt Hz1^{-1} level for 50%\sim 50\% of the sample, confirming that bright radio halos in less massive galaxy clusters are statistically rare.Comment: 7 pages, 4 figures. Conference proceeding of "The many facets of extragalactic radio surveys: towards new scientific challenges", 20-23 October 2105, Bologna, Ital

    Synoptic climatology and recent climate trends at Lake El'gygytgyn

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    Cutaneous manifestations in patients with COVID-19 : a preliminary review of an emerging issue

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    Background: The infection caused by the recently identified SARS-CoV-2, called COronaVIrus Disease-19 (COVID-19), has rapidly spread throughout the world. With the exponential increase of patients worldwide, the clinical spectrum of COVID-19 is being better defined and new symptoms are emerging. Numerous reports are documenting the occurrence of different cutaneous manifestations in COVID-19 patients. Objectives: To provide a brief overview of the COVID-19-associated cutaneous lesions. Methods: Literature search was performed in the PubMed, Scopus and Web of Science databases up to 30 April 2020. This narrative review summarizes the available data regarding clinical and histological features of COVID-19-associated skin manifestations. Results: Literature reports showed a great heterogeneity in COVID-19-associated cutaneous manifestations, as well as in their latency periods and associated extracutaneous symptoms. Pathogenic mechanisms are unknown, although the role of hyperactive immune response, complement activation and microvascular injury has been hypothesized. Based on our experience and the literature data, we subdivided the reported cutaneous lesions into six main clinical patterns: i) urticarial rash, ii) confluent erythematous/maculo-papular/morbilliform rash, iii) papulovesicular exanthem, iv) chilblain-like acral pattern, v) livedo reticularis/racemosa-like pattern, vi) purpuric "vasculitic" pattern. These six patterns can be merged into two main settings: the first one - inflammatory/exanthematous - including the first three groups cited above and the second one including the vasculopathic/vasculitic lesions of the last three aforementioned groups. Conclusions: The possible presence of cutaneous findings leading to suspect COVID-19 puts dermatologists in a relevant position. Further studies are needed to delineate the diagnostic and prognostic value of such cutaneous manifestations

    An unusual case of unilateral sinus disease may reveal the presence of a retained foreign body

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    Introduction: Differential diagnosis of unilateral sinus disease (USD) is important in clinical practice as it can be broad, and for which timely and effective treatment is important. With this report we would like to present a case of a patient with a foreign body retained in the left maxillary sinus for eight years. Presentation of case: A 50-year-old gardener referred to have been injured on the job in 2010. Even though he was wearing his safety helmet with face shield and earmuffs, he had the sensation to have been hit by an object coming from the soil, while he was using his grass trimmer. However, the patient was asymptomatic with no complications. After eight years, the man started experiencing left nasal obstruction associated with purulent discharge and ipsilateral headache. A fetid odor coming from inside the nose and described as “the carcass of a dog” led him to seek medical attention. The patient underwent a functional endoscopic sinus surgery (FESS) with septoplasty and a foreign body, consisting of a metal nail, was retrieved. Discussion: This case highlights a two key learning points. The first one concerns occupational safety measures; full-face shield helmets are the best option and should be employed in order to avoid the penetration of any possibly dangerous materials. Secondly, grass trimmers with more sophisticated designs are required in order to prevent injuries like this. Conclusions: Besides being peculiar because of the onset of clinical symptoms, this case report highlights the importance of full-face shield helmets and certified machinery

    once weekly administration of high dosage etanercept in patients with plaque psoriasis results of a pilot experience power study

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    Abstract Etanercept is a soluble tumour necrosis factor receptor fusion protein which is approved for the treatment of plaque psoriasis at the dose of either 25mg twice weekly (BIW) or, for the initial 12 weeks, 50mg BIW. Alternative dosing regimens have not been evaluated in psoriasis. In this study, we compare the efficacy and tolerability of two etanercept dosing regimens--50mg BIW and 100mg once weekly (OW)--for 12 weeks in 108 patients with moderate-to-severe recalcitrant psoriasis. Efficacy measures included Psoriasis Area and Severity Index (PASI), severity of pruritus recorded on a visual analogue scale (VAS) and the influence on quality of life assessed by means of Dermatology Life Quality Index (DLQI). Both etanercept regimens caused a significant change in all the efficacy parameters after 4 weeks and 12 weeks, at a comparable rate. At week 12, a PASI improvement of at least 50% from baseline (PASI 50) was achieved by 74% of patients treated with 50mg BIW and 78% of patients treated with 100mg OW. A PASI 75 response was obtained in 54% and 50% of patients treated with 50mg BIW and 100mg OW, respectively. Treatment was well tolerated with similar type and frequency of adverse events between the two groups
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