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- Abramowski, A., et al.
(författare)
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Revisiting the Westerlund 2 field with the HESS telescope array
- 2011
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 525, s. A46-
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Tidskriftsartikel (refereegranskat)abstract
- Aims. Previous observations with the HESS telescope array revealed the existence of extended very-high-energy (VHE; E > 100 GeV) gamma-ray emission, HESS J1023-575, coincident with the young stellar cluster Westerlund 2. At the time of discovery, the origin of the observed emission was not unambiguously identified, and follow-up observations have been performed to further investigate the nature of this gamma-ray source. Methods. The Carina region towards the open cluster Westerlund 2 has been re-observed, increasing the total exposure to 45.9 h. The combined dataset includes 33 h of new data and now permits a search for energy-dependent morphology and detailed spectroscopy. Results. A new, hard spectrum VHE gamma-ray source, HESS J1026-582, was discovered with a statistical significance of 7 sigma. It is positionally coincident with the Fermi LAT pulsar PSRJ1028-5819. The positional coincidence and radio/gamma-ray characteristics of the LAT pulsar favors a scenario where the TeV emission originates from a pulsar wind nebula. The nature of HESS J1023-575 is discussed in light of the deep HESS observations and recent multi-wavelength discoveries, including the Fermi LAT pulsar PSRJ1022-5746 and giant molecular clouds in the region. Despite the improved VHE dataset, a clear identification of the object responsible for the VHE emission from HESS J1023-575 is not yet possible, and contribution from the nearby high-energy pulsar and/or the open cluster remains a possibility.
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| 3. |
- Nakamoto, T, et al.
(författare)
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Dental panoramic radiograph as a tool to detect postmenopausal women with low bone mineral density : untrained general dental practitioners’ diagnostic performance
- 2003
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Ingår i: Osteoporosis International. - : Springer Science and Business Media LLC. - 0937-941X .- 1433-2965. ; 14:8, s. 659-664
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The detection of postmenopausal women with low bone mineral density (BMD) is an important strategy to reduce the incidence of osteoporotic fracture. Recent studies suggested that incidental findings on dental panoramic radiographs may be used as a tool to detect women with low BMD. However, little is known whether this finding is sufficiently assessed by untrained general dental practitioners (GDPs). The purpose of this study was to investigate: (1) the observer agreement and (2) the diagnostic efficacy in detecting women with low BMD, when untrained GDPs assess the appearance (normal or eroded) of the mandibular inferior cortex on dental panoramic radiographs of postmenopausal women. Twenty-seven GDPs were asked to classify the appearance of the mandibular inferior cortex on dental panoramic radiographs of 100 postmenopausal women who had completed BMD assessments of the lumbar spine and of the femoral neck. Intra- and inter-observer agreements were analyzed with kappa statistics. The diagnostic efficacy (sensitivity, specificity and predictive values) was analyzed by comparing two groups classified by the mandibular inferior cortex (women with normal and women with eroded mandibular inferior cortex) with those classified by BMD (women with normal BMD and women with osteopenia or osteoporosis). The mean sensitivity and specificity were 77 % and 40 %, respectively, when BMD of the lumbar spine was used as standard and 75 % and 39 %, respectively, when BMD of the femoral neck comprised the standard. Nineteen untrained GDPs (70 %) presented a moderate to almost perfect intra-observer agreement. We conclude that dental panoramic radiograph may be used in clinical dental practice to identify postmenopausal women who have undetected low BMD and should undergo further testing with bone densitometry.
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