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- Billgren, T, et al.
(författare)
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Refinement and interobserver agreement for the electrocardiographic Sclarovsky-Birnbaum Ischemia Grading System
- 2004
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Ingår i: Journal of Electrocardiology. - : Elsevier BV. - 1532-8430 .- 0022-0736. ; 37:3, s. 149-156
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Tidskriftsartikel (refereegranskat)abstract
- Background: Electrocardiogram-derived grades of ischemia at the time of patient presentation with acute myocardial infarction have proved useful in predicting the salvageability by reperfusion therapy, final infarct size, severity of left ventricular dysfunction, and short- and long-term prognosis. Subjects and Methods: The Sclarovsky-Birnbaum Ischemia Grading System based on the relation between the acute appearances of the T wave, the ST segment, and the QRS complex was considered as a means of enhanced ECG analysis in this group of patients. The evaluation of a training population (n = 46) resulted in refinement of the published description of the Sclarovsky-Birnbaum Ischemia Grading System, and a test population (n = 50) was utilized for investigating the interobserver agreement among 5 observers in determining the grade of ischemia. Results: The agreement among the observers applying the "refined" Sclarovsky-Birnbaum Ischemia Grading System was 0.89. Complete agreement was found for the ECGs of 80% of the patients, and the most common reason for disagreement was the application of the terminal T-negativity criterion. Conclusions: The refined Sclarovsky-Birnbaum Ischemia Grading System can be performed manually with low interobserver variability. It has potential for support of the acute myocardial infarction triage decision as an electrocardiographic method for evaluating the level of ischemic protection at the time of either pre-hospital or emergency-department presentation.
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15. |
- Dickson, L. T., et al.
(författare)
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Mechanisms to control laser-plasma coupling in laser wakefield electron acceleration
- 2022
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Ingår i: Physical Review Accelerators and Beams. - 2469-9888. ; 25:10
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Tidskriftsartikel (refereegranskat)abstract
- Experimental results, supported by precise modeling, demonstrate optimization of a plasma-based injector with intermediate laser pulse energy (<1 J), corresponding to a normalized vector potential a0=2.15, using ionization injection in a tailored plasma density profile. An increase in electron bunch quality and energy is achieved experimentally with the extension of the density downramp at the plasma exit. Optimization of the focal position of the laser pulse in the tailored plasma density profile is shown to efficiently reduce electron bunch angular deviation, leading to a better alignment of the electron bunch with the laser axis. Single peak electron spectra are produced in a previously unexplored regime by combining an early focal position and adaptive optic control of the laser wavefront by optimizing the symmetry of the prefocal laser energy distribution. Experimental results have been validated through particle-in-cell simulations using realistic laser energy, phase distribution, and temporal envelope, allowing for accurate predictions of difficult to model parameters, such as total charge and spatial properties of the electron bunches, opening the way for more accurate modeling for the design of plasma-based accelerators.
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- Harvey, P, et al.
(författare)
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The electric field instrument on the Polar satellite
- 1995
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Ingår i: Space Science Reviews. - 0038-6308 .- 1572-9672. ; 71, s. 583-596
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Tidskriftsartikel (refereegranskat)abstract
- The Polar satellite carries a system of four wire booms in the spacecraft spin plane and two rigid booms along the spin axis. Each of the booms has a spherical sensor at its tip along with nearby guard and stub surfaces whose potentials relative to that of their sphere are controlled by associated electronics. The potential differences between opposite sphere pairs are measured to yield the three components of the DC to >1 MHz electric field. Spheres can also be operated in a mode in which their collected current is measured to give information on the plasma density and its fluctuations. The scientific studies to be performed by this experiment as well as the mechanical and electrical properties of the detector system are described.
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