55 research outputs found
Isotope Shift Measurements of Stable and Short-Lived Lithium Isotopes for Nuclear Charge Radii Determination
Changes in the mean-square nuclear charge radii along the lithium isotopic
chain were determined using a combination of precise isotope shift measurements
and theoretical atomic structure calculations. Nuclear charge radii of light
elements are of high interest due to the appearance of the nuclear halo
phenomenon in this region of the nuclear chart. During the past years we have
developed a new laser spectroscopic approach to determine the charge radii of
lithium isotopes which combines high sensitivity, speed, and accuracy to
measure the extremely small field shift of an 8 ms lifetime isotope with
production rates on the order of only 10,000 atoms/s. The method was applied to
all bound isotopes of lithium including the two-neutron halo isotope Li-11 at
the on-line isotope separators at GSI, Darmstadt, Germany and at TRIUMF,
Vancouver, Canada. We describe the laser spectroscopic method in detail,
present updated and improved values from theory and experiment, and discuss the
results.Comment: 34 pages, 24 figures, 14 table
High precision branching ratio measurement for the superallowed β decay of [Formula Presented] A prerequisite for exacting tests of the standard model
Nonanalog Fermi and Gamow-Teller branches in the superallowed β decay of [Formula Presented] have been investigated using γ-ray and conversion-electron spectroscopy. Nine observed transitions, in conjunction with a recent shell model calculation, determine the branching ratio of the analog transition to be 99.5(1)%. The experimental upper limits for the Fermi decay to the [Formula Presented] and [Formula Presented] levels are in agreement with recent theoretical predictions. The [Formula Presented] value for the [Formula Presented] β decay is predicted to be 10405(9) keV. © 2003 The American Physical Society
The structure of mercantile communities in the Roman world : how open were Roman trade networks?
Liver-FibroSTARD checklist and glossary: tools for standardized design and reporting of diagnostic accuracy studies of liver fibrosis tests
Chronic liver diseases are highly prevalent and require an accurate evaluation of liver fibrosis to determine patient management. Many efforts have been made over this last decade to develop accurate non-invasive tools for liver fibrosis evaluation as alternative methods to liver biopsy. These non-invasive methods of liver fibrosis assessment including blood markers and liver stiffness measurement by elastography are increasingly well validated and contribute to safer and more practical clinical care for patients [1, 2]. These efforts have led to a dramatic increase in the number of diagnostic accuracy studies of liver fibrosis tests and to a proliferation of reports whose quality is very heterogeneous. [...
An extension of STARD statements for reporting diagnostic accuracy studies on liver fibrosis tests: the Liver-FibroSTARD standards
BACKGROUND & AIMS: Chronic liver diseases are highly prevalent and require an accurate evaluation of liver fibrosis to determine patient management. Over the last decade, great effort has been made to develop non-invasive liver fibrosis tests. The ensuing increase of literature is, however, impaired by extensive heterogeneity in the quality of published reports. The Standards for Reporting of Diagnostic Accuracy Studies (STARD), first published in 2003, were developed to improve the quality of research reports on diagnostic studies. We aimed to evaluate STARD statements in the setting of diagnostic studies on non-invasive liver fibrosis tests, and to propose an extended version developed specifically for those studies.
METHODS: Eight French experts evaluated STARD statement adequacy in 10 studies on non-invasive liver fibrosis tests and then developed an extended version with a glossary. The new checklist and glossary were independently evaluated by seven international experts.
RESULTS: Fourteen of the 25 STARD items were considered only partially adequate for the evaluation of diagnostic studies on non-invasive liver fibrosis tests. Inter-expert agreement was at least very good for 8 STARD items (32%), moderate for 9 (36%), and poor or very poor for 8 (32%). The experts\u27 proposals were developed into the new Liver-FibroSTARD standards including a checklist with 62 items/sub-items and a corresponding comprehensive glossary. New proposals were inserted in the 25 STARD items as a complementary module. Independent evaluation of the Liver-FibroSTARD checklist showed at least very good inter-expert agreement for 39 items/sub-items (63%), moderate agreement for 11 (18%), and poor or very poor agreement for only 12 (19%).
CONCLUSIONS: As a supplement of the STARD statements, the Liver-FibroSTARD checklist and its glossary are new tools specifically designed for the evaluation of diagnostic studies about non-invasive liver fibrosis tests
CARI'96 : actes du 3ème colloque africain sur la recherche en informatique = CARI'96 : proceedings of the 3rd African conference on research in computer science
In this paper, we show how to extract reliable informations about the shape of 3D objects, obtained from volume medical images. We present an optimal region-growing algorithm, that makes use of the differential characteristics of the object surface, and achieves a stable segmentation can be used to recognize and locate a target sub-structure on a global anatomic structure. (Résumé d'auteur
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