| 1. |
- Güsten, R., et al.
(författare)
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APEX - The Atacama Pathfinder Experiment
- 2006
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Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. ; 6267 I
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Konferensbidrag (refereegranskat)abstract
- APEX, the Atacama Pathfinder Experiment, has been successfully commissioned and is in operation now. This novel submillimeter telescope is located at 5107 m altitude on Llano de Chajnantor in the Chilean High Andes, on what is considered one of the world's outstanding sites for submillimeter astronomy. The primary reflector with 12 m diameter has been carefully adjusted by means of holography. Its surface smoothness of 17-18 μm makes APEX suitable for observations up to 200 μm, through all atmospheric submm windows accessible from the ground.
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| 2. |
- Pagels, A., et al.
(författare)
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Millimetre VLBI monitoring of AGN with sub-milliarcsecond resolution
- 2004
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Ingår i: in "Proceedings of the 7th European VLBI Network Symposium", Oct. 2004, Toledo, eds. R. Bachiller, F. Colomer, J.F. Desmurs, P. de Vicente, Obs. Astronómico Nacional, Alcala de Henares, Spain. ; , s. 7-10
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 3. |
- Alberdi, A., et al.
(författare)
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The high-frequency compact radio structure of the peculiar quasar 4C 39.25
- 1997
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Ingår i: Astronomy and Astrophysics. - : Springer-Verlag. - 0004-6361 .- 1432-0746. ; 327:2, s. 513-521
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Tidskriftsartikel (refereegranskat)abstract
- We present new high angular resolution images of the compact non-thermal radio source 4C 39.25 obtained from VLBI observations at λ1.3cm, λ7mm, and λ3mm wavelengths. These maps and Gaussian model-fits show that the milli-arcsecond to sub-milliarcsecond structure of 4C 39.25 consists of a complex bent core-jet structure with embedded moving and stationary VLBI components. Facilitated by the small observing beams and high angular resolutions obtained at mm-wavelengths, we measured the relative positions of the jet components with an accuracy of a few hundred micro-arcseconds. This allows the detailed followup of the ongoing merging process of a westward superluminally moving component (b_) with a stationary component a_, located at ~2.9 mas east of the putative core d_. In contrast to the other components of the structure with steeper spectra, the westernmost component d_ exhibits an inverted spectrum peaking between λ7mm and λ3mm, thus further supporting its identification as the VLBI core, self-absorbed at longer wavelengths. From two VLBI maps obtained nearly simultaneously at λ7mm and λ1.3cm, we made the first spectral index map of 4C 39.25 in this wavelength regime. The main characteristics of the spectral index distribution of the jet are pronounced changes of the spectral index between orientations parallel and transverse to the jet axis. Near the merging components a_ and b_ the spectral index steepens with increasing separation from d_. However, in the bridge of emission c_, which connects d_ with a_ and b_, the spectral index gradient has a direction transverse to the jet axis, suggesting a frequency dependent jet curvature and edge-brightening. A brief discussion of this behaviour within current jet models is presented.
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| 4. |
- Madsen, C. L., et al.
(författare)
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The left atrial appendage closure by surgery-2 (LAACS-2) trial protocol rationale and design of a randomized multicenter trial investigating if left atrial appendage closure prevents stroke in patients undergoing open-heart surgery irrespective of preoperative atrial fibrillation status and stroke risk
- 2023
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Ingår i: American Heart Journal. - 0002-8703. ; 264, s. 133-142
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Tidskriftsartikel (refereegranskat)abstract
- Background Current recommendations regarding the use of surgical left atrial appendage (IAA) closure to prevent thromboembolisms lack high-level evidence. Patients undergoing open-heart surgery often have several cardiovascular risk factors and a high occurrence of postoperative atrial fibrillation (AF)-with a high recurrence rate-and are thus at a high risk of stroke. Therefore, we hypothesized that concomitant IAA closure during open-heart surgery will reduce mid-term risk of stroke independently of preoperative AF status and CHA 2 DS 2 -VASc score. Methods This protocol describes a randomized multicenter trial. Consecutive participants & GE;18 years scheduled for first-time planned open-heart surgery from cardiac surgery centers in Denmark, Spain, and Sweden are included. Both patients with a previous diagnosis of paroxysmal or chronic AF, as well as those without AF, are eligible to participate, irrespective of their CHA 2 DS 2 -VASc score. Patients already planned for ablation or IAA closure during surgery, with current endocarditis, or where follow-up is not possible are considered noneligible. Patients are stratified by site, surgery type, and preoperative or planned oral anticoagulation treatment. Subsequently, patients are randomized 1:1 to either concomitant IAA closure or standard care (ie, open IAA). The primary outcome is stroke, including transient ischemic attack, as assigned by 2 independent neurologists blinded to the treatment allocation. To recognize a 60% relative risk reduction of the primary outcome with LAA closure, 1,500 patients are randomized and followed for 2 years (significance level of 0.05 and power of 90%). Conclusions The LAACS-2 trial is likely to impact the LAA closure approach in most patients undergoing open-heart surgery. Trial registration: NCT03724318. (Am HeartJ 2023;264:133-142.)
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| 5. |
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| 6. |
- Krischbaum, T.T., et al.
(författare)
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Towards the event horizon - the vicinity of AGN at micro-arcsecond resolution
- 2004
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Ingår i: in "Proceedings of the 7th European VLBI Network Symposium", Oct. 2004, Toledo, eds. R. Bachiller, F. Colomer, J.F. Desmurs, P. de Vicente, Obs. Astronómico Nacional, Alcala de Henares, Spain. ; , s. 15-18
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 8. |
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