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- Bravo, L, et al.
(författare)
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- 2021
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swepub:Mat__t
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- Tabiri, S, et al.
(författare)
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- 2021
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swepub:Mat__t
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- Glasbey, JC, et al.
(författare)
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- 2021
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swepub:Mat__t
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- Egron, E., et al.
(författare)
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Single-dish and VLBI observations of Cygnus X-3 during the 2016 giant flare episode
- 2017
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Ingår i: Monthly Notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 471:3, s. 2703-2714
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Tidskriftsartikel (refereegranskat)abstract
- In 2016 September, the microquasar Cygnus X-3 underwent a giant radio flare, which was monitored for 6 d with the Medicina Radio Astronomical Station and the Sardinia Radio Telescope. Long observations were performed in order to follow the evolution of the flare on an hourly scale, covering six frequency ranges from 1.5 to 25.6 GHz. The radio emission reached a maximum of 13.2 +/- 0.7 Jy at 7.2 GHz and 10 +/- 1 Jy at 18.6 GHz. Rapid flux variations were observed at high radio frequencies at the peak of the flare, together with rapid evolution of the spectral index: a steepened from 0.3 to 0.6 (with S-nu alpha nu(-alpha)) within 5 h. This is the first time that such fast variations are observed, giving support to the evolution from optically thick to optically thin plasmons in expansion moving outward from the core. Based on the Italian network (Noto, Medicina and SRT) and extended to the European antennas (Torun, Yebes, Onsala), very long baseline interferometry (VLBI) observations were triggered at 22 GHz on five different occasions, four times prior to the giant flare, and once during its decay phase. Flux variations of 2 h duration were recorded during the first session. They correspond to a mini-flare that occurred close to the core 10 d before the onset of the giant flare. From the latest VLBI observation we infer that 4 d after the flare peak the jet emission was extended over 30 mas.
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- Enrichi, Francesco, et al.
(författare)
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Silver doping of silica-hafnia waveguides containing Tb3+/Yb3+ rare earths for downconversion in PV solar cells
- 2016
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Ingår i: Optical materials (Amsterdam). - : Elsevier BV. - 0925-3467 .- 1873-1252. ; 60, s. 264-269
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this paper is to study the possibility to obtain an efficient downconverting waveguide which combines the quantum cutting properties of Tb3+/Yb3+ codoped materials with the optical sensitizing effects provided by silver doping. The preparation of 70SiO(2)-30HfO(2) glass and glass-ceramic waveguides by sol-gel route, followed by Ag doping by immersion in molten salt bath is reported. The films were subsequently annealed in air to induce the migration and/or aggregation of the metal ions. Results of compositional and optical characterization are given, providing evidence for the successful introduction of Ag in the films, while the photoluminescence emission is strongly dependent on the annealing conditions. These films could find potential applications as downshifting layers to increase the efficiency of PV solar cells
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11. |
- Frank, U, et al.
(författare)
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ESVM Guideline on peripheral arterial disease
- 2019
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Ingår i: VASA. Zeitschrift fur Gefasskrankheiten. - : Hogrefe Publishing Group. - 0301-1526. ; 48:Suppl 102, s. 7-79
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Tidskriftsartikel (refereegranskat)
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- Lisi, Matteo, et al.
(författare)
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Right ventricular longitudinal deformation correlates closely with right ventricular myocardial fibrosis in patients with end-stage heart failure
- 2013
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Ingår i: European Heart Journal. - : Oxford University Press. - 0195-668X .- 1522-9645. ; 34, s. 780-780
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Background: Right ventricular (RV) longitudinal strain (LS) plays a key role in the evaluation of its systolic performance and clinical outcomein patients with refractory heart failure (HF). This study sought to determine the value of RVLS for prediction of RV myocardial fibrosis inpatients with severe HF undergoing heart transplantation (HTx).Methods: The cohort we studied consists of 24 patients with severe systolic HF (left ventricular ejection fraction ≤ 25%; NYHA class IV) referred between 2009 and 2013 for a simultaneous right heartcatheterization and echocardiographic evaluation before HTx.RVLS by Speckle Tracking Echocardiography (STE) was used to assess free-wall RVLS, global cavity RVLS (including all segments in the apical 4 chamber view and right atrial LS (RALS), RV fractional area change (RVFAC), RV sphericity index (RVSI) and tricuspid annular plane systolic excursion (TAPSE) were also measured. All patients underwent HTx 12±34 days afterwards. From the explanted hearts a 1 x 0,5 cmmyocardial sample of the RV lateral free wall was obtained and stainedwith hematoxylin-eosin and Masson's trichrome. The ratio of the fibrotic area to the total surface area of each section was used to estimate the extent of RV myocardial fibrosis (percentage) as (fibrotis area-total area) x 100.Results: A good correlation was found between the extent of RVmyocardial fibrosis and free-wall RVLS (r=0.72; p<0.0001), global RVLS (r=0.49; p<0.0001), RVSI (r=0.47; p<0.0001), and RALS (r= -0.46; p=0.005), with a poorer correlation with TAPSE (r= -0.32; p=0.01) and RVFAC (r= -0.25; p=ns). Of these indeces, free-wall RVLS had the strongest diagnostic accuracy for detecting severe RV myocardialfibrosis (AUC = 0.87).Conclusions: In late stage HF patients, right ventricular free wallmyocardial deformation is the best functional measure that correlateswith the extent of myocardial fibrosis. These findings should have clinical implications when interpreting other RV measurements.
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- Larsson, Josefin, et al.
(författare)
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A close look at the γ-ray emitting narrow-line seyfert 1 FBQS J1644+2619
- 2018
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Ingår i: Proceedings of Science. - : Sissa Medialab Srl.
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Konferensbidrag (refereegranskat)abstract
- FBQS J1644+2619 is one of the most recently discovered γ-ray emitting Narrow-Line Seyfert 1s (NLSy1s). Here we present a multiwavelength analysis of this source, focussing on a recent 80 ks X-ray observation with XMM-Newton. The spectral energy distribution of the source is similar to the other γ-ray NLSy1s, confirming its blazar-like nature. The X-ray spectrum is characterised by a hard photon index (Γ = 1.66) above 2 keV and a soft excess at lower energies. The hard photon index provides clear evidence that inverse Compton emission from the jet dominates the spectrum, while the soft excess can be explained by a contribution from the underlying Seyfert emission. This contribution can be fitted by reflection of emission from the base of the jet, as well as by Comptonisation in a warm, optically thick corona. We also compare these results with X-ray observations of other γ-ray NLSy1s. The majority of the sources have similar X-ray spectra, with properties intermediate between blazars and radio-quiet NLSy1s.
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- Larsson, Josefin, et al.
(författare)
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FBQS J1644+2619 : multiwavelength properties and its place in the class of gamma-ray emitting Narrow Line Seyfert 1s
- 2018
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Ingår i: Monthly notices of the Royal Astronomical Society. - : OXFORD UNIV PRESS. - 0035-8711 .- 1365-2966. ; 476:1, s. 43-55
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Tidskriftsartikel (refereegranskat)abstract
- A small fraction of Narrow Line Seyfert 1s (NLSy1s) are observed to be gamma-ray emitters. Understanding the properties of these sources is of interest since the majority of NLSy1s are very different from typical blazars. Here, we present a multifrequency analysis of FBQS J1644+2619, one of the most recently discovered gamma-ray emitting NLSy1s. We analyse an similar to 80 ks XMM-Newton observation obtained in 2017, as well as quasi-simultaneous multi-wavelength observations covering the radio-gamma-ray range. The spectral energy distribution of the source is similar to the other gamma-ray NLSy1s, confirming its blazar-like nature. The X-ray spectrum is characterized by a hard photon index (Gamma = 1.66) above 2 keV and a soft excess at lower energies. The hard photon index provides clear evidence that inverse Compton emission from the jet dominates the spectrum, while the soft excess can be explained by a contribution from the underlying Seyfert emission. This contribution can be fitted by reflection of emission from the base of the jet, as well as by Comptonization in a warm, optically thick corona. We discuss our results in the context of the other gamma-ray NLSy1s and note that the majority of them have similar X-ray spectra, with properties intermediate between blazars and radio-quiet NLSy1s.
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