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- Cristaldi, A., et al.
(författare)
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DYNAMIC PROPERTIES ALONG THE NEUTRAL LINE OF A DELTA SPOT INFERRED FROM HIGH-RESOLUTION OBSERVATIONS
- 2014
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Ingår i: Astrophysical Journal. - 0004-637X .- 1538-4357. ; 789:2, s. 162-
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Tidskriftsartikel (refereegranskat)abstract
- Delta (delta) spots are complex magnetic configurations of sunspots characterized by umbrae of opposite polarity sharing a common penumbra. In order to investigate the fine structure of the region separating the two magnetic polarities of a delta spot, we studied the morphology, the magnetic configuration, and the velocity field in such a region using observations of active region (AR) NOAA 11267 obtained with the CRisp Imaging SpectroPolarimeter (CRISP) at the Swedish Solar Telescope on 2011 August 6. The analysis of CRISP data shows upflows and downflows of similar to +/- 3 km s(-1) in proximity of the delta spot polarity inversion line (PIL), and horizontal motions along the PIL of the order of similar to 1 km s(-1). The results obtained from the SIR inversion of CRISP data also indicate that the transverse magnetic field in the brighter region separating the two opposite magnetic polarities of the delta spot is tilted about similar to 45 degrees with respect to the PIL. Solar Dynamics Observatory/Helioseismic and Magnetic Imager observations confirm the presence of motions of similar to +/- 3 km s(-1) in proximity of the PIL, which were observed to last 15 hr. From the data analyzed, we conclude that the steady, persistent, and subsonic motions observed along the delta spot PIL can be interpreted as being due to Evershed flows occurring in the penumbral filaments that show a curved, wrapped configuration. The fluting of the penumbral filaments and their bending, continuously increased by the approaching motion of the negative umbra toward the positive one, give rise to the complex line-of-sight velocity maps that we observed.
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- Falco, M., et al.
(författare)
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High-resolution observations of a light bridge in a decaying sunspot
- 2014
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Ingår i: SEVENTH EUROPEAN SUMMER SCHOOL ON EXPERIMENTAL NUCLEAR ASTROPHYSICS. - : AIP Publishing LLC. - 9780735412293 ; , s. 221-223
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Konferensbidrag (refereegranskat)abstract
- Light brigde are small-scale structures observed in the solar photosphere which separate the umbra of a sunspot in two or more parts. On 6 August 2011, we observed at the Swedish 1-m Solar Telescope a large sunspot of the Active Region NOAA 11263 with a light bridge. We acquired full Stokes profiles over the Fe I line at 630.25 nm and spectroscopic data along the Fe I line profile at 557.6 nm for about an hour, from 09: 53: 32 UT to 10: 48: 43 UT. Data in the core of the Ca II H line at 396.8 nm were simultaneously acquired. The Active Region was also observed by SDO and SOT/HINODE to study the dynamics and the magnetic evolution of the light bridge. Thanks to these high-resolution observations the fine structure of this element and its properties are better studied to determine the physical processes behind its formation.
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- Hansen, Björn M., et al.
(författare)
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Relationship of White Matter Lesions with Intracerebral Hemorrhage Expansion and Functional Outcome : MISTIE II and CLEAR III
- 2020
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Ingår i: Neurocritical Care. - : Springer Science and Business Media LLC. - 1541-6933 .- 1556-0961. ; 33:2, s. 516-524
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Tidskriftsartikel (refereegranskat)abstract
- Background/Objective: Intracerebral hemorrhage (ICH) patients commonly have concomitant white matter lesions (WML) which may be associated with poor outcome. We studied if WML affects hematoma expansion (HE) and post-stroke functional outcome in a post hoc analysis of patients from randomized controlled trials. Methods: In ICH patients from the clinical trials MISTIE II and CLEAR III, WML grade on diagnostic computed tomography (dCT) scan (dCT, < 24 h after ictus) was assessed using the van Swieten scale (vSS, range 0–4). The primary outcome for HE was > 33% or > 6 mL ICH volume increase from dCT to the last pre-randomization CT (< 72 h of dCT). Secondary HE outcomes were: absolute ICH expansion, > 10.4 mL total clot volume increase, and a subgroup analysis including patients with dCT < 6 h after ictus using the primary HE definition of > 33% or > 6 mL ICH volume increase. Poor functional outcome was assessed at 180 days and defined as modified Rankin Scale (mRS) ≥ 4, with ordinal mRS as a secondary endpoint. Results: Of 635 patients, 55% had WML grade 1–4 at dCT (median 2.2 h from ictus) and 13% had subsequent HE. WML at dCT did not increase the odds for primary or secondary HE endpoints (P ≥ 0.05) after adjustment for ICH volume, intraventricular hemorrhage volume, warfarin/INR > 1.5, ictus to dCT time in hours, age, diabetes mellitus, and thalamic ICH location. WML increased the odds for having poor functional outcome (mRS ≥ 4) in univariate analyses (vSS 4; OR 4.16; 95% CI 2.54–6.83; P < 0.001) which persisted in multivariable analyses after adjustment for HE and other outcome risk factors. Conclusions: Concomitant WML does not increase the odds for HE in patients with ICH but increases the odds for poor functional outcome. Clinical Trial Registration: http://www.clinicaltrials.gov trial-identifers: NCT00224770 and NCT00784134.
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