| 1. |
- Düllmann, Ch. E., et al.
(författare)
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Production and Decay of Element 114: High Cross Sections and the New Nucleus 277Hs
- 2010
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Ingår i: Physical Review Letters. - 1079-7114. ; 104:25
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Tidskriftsartikel (refereegranskat)abstract
- The fusion-evaporation reaction 244Pu(48Ca, 3-4n)288,289114 was studied at the new gas-filled recoil separator TASCA. Thirteen correlated decay chains were observed and assigned to the production and decay of 288,289114. At a compound nucleus excitation energy of E* = 39.8-43.9 MeV, the 4n evaporation channel cross section was 9.8(-3.1)(+3.9) pb. At E* = 36.1-39.5 MeV, that of the 3n evaporation channel was 8.0-(+7.4)(4.5) pb. In one of the 3n evaporation channel decay chains, a previously unobserved alpha branch in 281Ds was observed ( probability to be of random origin from background: 0.1%). This alpha decay populated the new nucleus 277Hs, which decayed by spontaneous fission after a lifetime of 4.5 ms.
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| 2. |
- Gates, J. M., et al.
(författare)
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First Superheavy Element Experiments at the GSI Recoil Separator TASCA: The Production and Decay of Element 114 in the 244Pu(48Ca,3-4n) Reaction
- 2011
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 83:5
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Tidskriftsartikel (refereegranskat)abstract
- Experiments with the new recoil separator, Transactinide Separator and Chemistry Apparatus (TASCA), at the GSI were performed by using beams of Ca-48 to irradiate targets of Pb206-208, which led to the production of No252-254 isotopes. These studies allowed for evaluation of the performance of TASCA when coupled to a new detector and electronics system. By following these studies, the isotopes of element 114 ((288-291)114) were produced in irradiations of Pu-244 targets with Ca-48 beams at compound nucleus excitation energies around 41.7 and 37.5 MeV, demonstrating TASCA's ability to perform experiments with picobarn-level cross sections. A total of 15 decay chains were observed and were assigned to the decay of 288-291114. A new a-decay branch in (281)Ds was observed, leading to the new nucleus (277)Hs.
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| 3. |
- Liebe-Harkort, Carola, 1966-
(författare)
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Oral Disease and Health Patterns : Dental and Cranial Paleopathology of the Early Iron Age Population at Smörkullen in Alvastra, Sweden
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In skeletal remains of ancient populations, evidence of dental and craniofacial pathology is often well preserved in the form of lesions on the teeth or bones. Meticulous, detailed recording of these lesions provides baseline data on which a realistic assessment can be made of the probable impact of dental diseases and its sequelae on health of these earlier populations. In the present thesis, dental and cranial pathology were recorded in the remains of an Iron Age population, with special reference to the possible impact of such conditions on general health and well-being. The skeletal remains had been excavated early last century from the burial ground Smörkullen, Alvastra, Östergötland, in Eastern Central Sweden: osteological analyses showed that the material comprised the remains of 65 subadult individuals and 104 adult individuals of both sexes. The dental status of most of the adult individuals was poor. Calculus, periodontitis, moderate and severe carious lesions and periapical infections were recorded. In contrast, subadult showed less evidence of dental disease. The results indicate that the perception of health in adults was probably negatively affected by their poor oral status. The dental status of subadults, on the other hand, was unlikely to have had a negative impact on their general well-being. A sex difference was observed in the material, males tending to more ongoing disease than females. Overall, the frequencies of both dental and cranial pathologies increased with age. Caries frequency in the material was noticeable higher than in numerous other studies in Scandinavian populations. Although the high caries rates at Smörkullen may be attributable to a diet rich in carbohydrates, the result may to some extent have been influenced by observer experience. Caries rates in other populations are likely to be under-estimated in comparison with Smörkullen. However, methodological factors alone cannot not explain all the observed differences. The recording of cranial pathologies disclosed malnutrition and upper respiratory problems in all age groups in the Smörkullen material. This most certainly affected their well-being. In some cases the pathology observed was directly associated with life-threatening conditions. Analyses of combinations of pathologies suggest that a combination of linear enamel hypoplasias and cribra orbitalia, mainly observed in those who died before the age of fifteen, may have been related to a lower probability of survival.
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