| 2. |
- Lundquist, J., et al.
(författare)
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The PAMELA Calorimeter Identification Capabilities
- 2005
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Ingår i: Proceedings of the 29th International Cosmic Ray Conference, vol 3:OG1. ; , s. 305-308
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Konferensbidrag (refereegranskat)abstract
- A silicon-tungsten imaging calorimeter has been designed, built and successfully integrated in the PAMELA satellite-bome apparatus. The main physics task of the experiment is the measurement of the flux of antiprotons, positrons and light nuclei in the cosmic radiation. The purpose of the calorimeter is to separate antiprotons and positrons from the vast background of cosmic-ray electrons and protons, respectively. In this work we present the identification capabilities of the calorimeter obtained using both Monte Carlo and test beam data. We show that the calorimeter can provide a proton rejection factor of about 105 while keeping a similar to 90% efficiency in selecting electrons and positrons. The PAMELA calorimeter is therefore able to provide the identification power needed to reach the primary scientific objectives of PAMELA.
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| 3. |
- Petersen, Steffen E, et al.
(författare)
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Differentiation of athlete's heart from pathological forms of cardiac hypertrophy by means of geometric indices derived from cardiovascular magnetic resonance.
- 2005
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Ingår i: Journal of cardiovascular magnetic resonance : official journal of the Society for Cardiovascular Magnetic Resonance. - 1097-6647. ; 7:3, s. 551-8
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: Determination of the underlying etiology of left ventricular hypertrophy (LVH) is a common, challenging, and critical clinical problem. The authors aimed to test whether pathological LVH, such as occurs in hypertrophic cardiomyopathy (HCM), hypertensive heart disease, or aortic stenosis, and physiological LVH in athletes, can be distinguished by means of left ventricular volume and geometric indices, derived from cardiovascular magnetic resonance imaging. METHODS: A total of 120 subjects were studied on a 1.5 Tesla MR (Sonata, Siemens Medical Solutions, Erlangen, Germany) scanner, comprising healthy volunteers (18), competitive athletes (25), patients with HCM (35), aortic stenosis (24), and hypertensive heart disease (18). Left ventricular mass index, ejection fraction, end-diastolic, end-systolic and stroke volume index, diastolic wall thickness, wall thickness ratio and diastolic and systolic wall-to-volume ratios were determined. RESULTS: Left ventricular (LV) mass indices were similar for all forms of LVH (p > 0.05), which were at least 35% higher than those obtained in healthy volunteers (p < 0.05). Multiple logistic regression showed that the percentage of correctly predicted diagnoses was 100% for athlete's heart, 80% for hypertrophic cardiomyopathy, 54% for aortic stenosis, and 22% for hypertensive heart disease. Using a receiver operating curve-determined cut-off value for diastolic wall-to-volume ratio of less than 0.15 mm x m2 x ml(-1), athletes' hearts could be differentiated from all forms of pathological cardiac hypertrophy with 99% specificity. CONCLUSIONS: Athlete's heart can be reliably distinguished from all forms of pathological cardiac hypertrophy using CMR-derived LV volume and geometric indices, but pathological forms of LVH present with overlapping cardiac hypertrophy phenotypes. This capability of CMR should be of high clinical value.
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