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- Veres, P., et al.
(författare)
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Observation of inverse Compton emission from a long gamma-ray burst
- 2019
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Ingår i: Nature. - : NATURE PUBLISHING GROUP. - 0028-0836 .- 1476-4687. ; 575:7783, s. 459-
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Tidskriftsartikel (refereegranskat)abstract
- Long-duration gamma-ray bursts (GRBs) originate from ultra-relativistic jets launched from the collapsing cores of dying massive stars. They are characterized by an initial phase of bright and highly variable radiation in the kiloelectron volt-to-mega electronvoltband, which is probably produced within the jet and lasts from milliseconds to minutes, known as the prompt emission(1,2). Subsequently, the interaction of the jet with the surrounding medium generates shock waves that are responsible for the afterglow emission, which lasts from days to months and occurs over a broad energy range from the radio to the gigaelectronvolt bands(1-6). The afterglow emission is generally well explained as synchrotron radiation emitted by electrons accelerated by the external shock(7-9). Recently, intense long-lasting emission between 0.2 and 1 teraelectronvolts was observed from GRB 190114C(10,11). Here we report multifrequency observations of GRB 190114C, and study the evolution in time of the GRB emission across 17 orders of magnitude in energy, from 5 x 10(-6) to 10(12) electronvolts. We find that the broadband spectral energy distribution is double-peaked, with the teraelectronvolt emission constituting a distinct spectral component with power comparable to the synchrotron component. This component is associated with the afterglow and is satisfactorily explained by inverse Compton up-scattering of synchrotron photons by high-energy electrons. We find that the conditions required to account for the observed teraelectronvolt component are typical for GRBs, supporting the possibility that inverse Compton emission is commonly produced in GRBs.
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- Murphy, Declan G., et al.
(författare)
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Downsides of Robot-assisted Laparoscopic Radical Prostatectomy: Limitations and Complications
- 2010
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Ingår i: European Urology. - : Elsevier BV. - 1873-7560 .- 0302-2838. ; 57:5, s. 735-746
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Tidskriftsartikel (refereegranskat)abstract
- Context: Robot-assisted laparoscopic radical prostatectomy (RALP) using the da Vinci Surgical System (Intuitive Surgical, Sunnyvale, CA, USA) is now in widespread use for the management of localised prostate cancer (PCa). Many reports of the safety and efficacy of this procedure have been published. However, there are few specific reports of the limitations and complications of RALP. Objective: The primary purpose of this review is to ascertain the downsides of RALP by focusing on complications and limitations of this approach. Evidence acquisition: A Medline search of the English-language literature was performed to identify all papers published since 2001 relating to RALP. Papers providing data on technical failures, complications, learning curve, or other downsides of RALP were considered. Of 412 papers identified, 68 were selected for review based on their relevance to the objective of this paper. Evidence synthesis: RALP has the following principal downsides: (1) device failure occurs in 0.2-0.4% of cases; (2) assessment of functional outcome is unsatisfactory because of nonstandardised assessment techniques; (3) overall complication rates of RALP are low, although higher rates are noted when complications are reported using a standardised system; (4) long-term oncologic data and data on high-risk PCa are limited; (5) a steep learning curve exists, and although acceptable operative times can be achieved in <20 cases, positive surgical margin (PSM) rates may require experience with >80 cases before a plateau is achieved; (6) robotic assistance does not reduce the difficulty associated with obese patients and those with large prostates, middle lobes, or previous surgery, in whom outcomes are less satisfactory than in patients without such factors; (7) economic barriers prevent uniform dissemination of robotic technology. Conclusions: Many of the downsides of RALP identified in this paper can be addressed with longer-term data and more widespread adoption of standardised reporting measures. The significant learning curve should not be understated, and the expense of this technology continues to restrict access for many patients. (C) 2009 European Association of Urology. Published by Elsevier B. V. All rights reserved.
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