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| 2. |
- Aleksandrov, D., et al.
(författare)
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Invariant mass spectrum and alpha-n correlation function studied in the fragmentation of He-6 on a carbon target
- 1998
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Ingår i: Nuclear Physics A. - 0375-9474. ; 633:2, s. 234-246
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Tidskriftsartikel (refereegranskat)abstract
- Momentum distributions and invariant mass spectra from the breakup of He-6 ions with an energy of 240 MeV/u interacting with a carbon target have been studied. The data were used to extract information about the reaction mechanism which is influenced by the structure of He-6. It is found that the dominant reaction mechanism is a two-step process: knock out of one neutron followed by the decay of the He-5 resonance. The shape of the (alpha+n) two-body invariant mass spectrum is interpreted as mainly reflecting the 5He ground state which is a J(pi) = 3/2(-) resonance. However, no evidence for correlations between cu particles and neutrons is observed in the momentum widths of the distributions. It is demonstrated that a combined analysis of the two-body invariant mass spectrum and an appropriate correlation function may be used to determine the properties of the intermediate resonance. (C) 1998 Elsevier Science B.V.
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| 3. |
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| 4. |
- Marques, F. M., et al.
(författare)
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Neutrons from the breakup of C-19
- 1996
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Ingår i: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - 0370-2693. ; 381:4, s. 407-412
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Tidskriftsartikel (refereegranskat)abstract
- Neutrons arising from the breakup of a 30 MeV/nucleon C-19 beam on a tantalum target have been measured using the 98 element array DEMON. A narrow, forward peaked neutron angular distribution, with a corresponding momentum spread considerably smaller than those measured simultaneously for N-21, O-22 and F-24 was observed for charged fragments with Z
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| 6. |
- Schnack-Petersen, H, et al.
(författare)
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Superdeformed triaxial bands in Lu-163,165
- 1995
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Ingår i: Nuclear Physics A. - : Elsevier BV. - 0375-9474. ; 594:2, s. 175-202
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Tidskriftsartikel (refereegranskat)abstract
- An experimental investigation of the nucleus 165Lu, using the reactions 138Ba(31P,4n) 165Lu and 150Sm(19F,4n) 165Lu at beam energies of E = 155 and 95 MeV, respectively, has been performed. Among other additions to the existing level scheme, a new band, with transition energies almost identical to a strongly deformed (β2 0.42) πi13/2[660 1/2+] band recently discovered in 163Lu has been established. A theoretical analysis of the structure of the two Lu isotopes, 165Lu and 163Lu is carried out by detailed calculations of total potential energy surfaces for specific configurations. By a diabatic treatment of crossings specific proton configurations as πi13/2[660 1/2+] are identified throughout the deformation space and as a function of spin. It is found as a general feature that well deformed local minima of considerable nonaxial symmetry coexist with a normal deformed global minimum. The depth of these local minima depend on configuration. The structure of the different global and local minima found in these surfaces are analysed and discussed in terms of occupation of available basis configurations and their orientation relative to the rotation axis. The strongly deformed minima are found to belong to a group of superdeformed triaxial structures, expected to appear at low energies for certain favourable combinations of proton and neutron numbers.
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| 7. |
- Axelsson, L., et al.
(författare)
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Two-proton emission in the decay of Ar-31
- 1998
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Ingår i: Nuclear Physics A. - 0375-9474. ; 628:3, s. 345-362
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Tidskriftsartikel (refereegranskat)abstract
- Several beta-delayed two-proton branches were observed in the decay of Ar-31, the most intense ones proceeding through the isobaric analogue state (IAS) in Cl-31. The mechanism of the two-proton emission is studied via the energy and angular distributions of the two protons, Simultaneous emission of the two protons fits the present data well, sequential decays might also describe them. Independent of the decay mechanism, a spin of 5/2 for the IAS is suggested, An improved limit on the direct two-proton emission fi om the ground state of Ar-31 is presented, (C) 1998 Elsevier Science B.V.
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| 11. |
- Lernmark, Å, et al.
(författare)
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Heterogeneity of islet pathology in two infants with recent onset diabetes mellitus
- 1995
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Ingår i: Virchows Archiv. - 0945-6317. ; 425:6, s. 631-640
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Tidskriftsartikel (refereegranskat)abstract
- The mechanisms by which the beta cells of pancreatic islets are destroyed in insulin-dependent diabetes mellitus (IDDM) are poorly understood. In this report the pancreatic histo- and immunopathology of two children, both HLA-DR 3/4, DQ 2/8 positive and who both died from cerebral oedema within a day of clinical diagnosis of IDDM, were investigated. Patient 1, a 14-month-old girl, had a 4-week history of polydipsia and polyuria. Patient 2, a 3-year-old boy, had 2 days of illness. Both patients had a similarly severe loss of insulin cells but differed markedly as to the extent of lymphocytic islet infiltration (insulitis). Apart from insulitis, marked islet macrophage infiltration was demonstrated in both patients with the HAM-56 monoclonal antibody. Neither patient showed aberrant expression of HLA class II antigens on insulin-immunoreactive cells, but allele-specific HLA-DQ8 expression was evident on endothelial cells. Glutamic acid decarboxylase immunoreactivity was detected in both insulin- and glucagon-immunoreactive cells. It is concluded that the heterogeneity of islet pathology, especially insulitis, may reflect different dynamics and extent rather than different pathomechanisms of immune destruction of islets in IDDM.
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| 12. |
- Munch-Petersen, C., et al.
(författare)
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Concrete strategy for the Oresund Tunnel
- 1997
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Ingår i: Betonwerk und Fertigteil-Technik / Concrete Precasting Plant and Technology. - 0373-4331. ; 63:11, s. 44-54
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- This paper gives a short review of the most requirements for the concrete to be used for the 3.510 m long immersed tunnel from Amager (outside Copenhagen Airport) to an artificial double island south of Saltholm (in the middle of Oresund). The basis for the requirements is shortly commented.
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| 14. |
- Vought, Lena B. M., et al.
(författare)
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Effect of riparian structure, temperature and channel morphometry on detritus processing in channelized and natural woodland streams in southern Sweden
- 1998
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Ingår i: Aquatic conservation. - 1052-7613 .- 1099-0755. ; 8:2, s. 273-285
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Tidskriftsartikel (refereegranskat)abstract
- 1. Ten south Swedish streams were selected to represent two distinct types—natural woodland streams and channelized streams. Measurements were made on leaching, decomposition and microbial respiration of the dominant riparian vegetation (European Black Alder), structure of the benthic macroinvertebrate community, macroinvertebrates inhabiting leaf material, channel morphometry, macrophyte composition, water chemistry and total accumulated degree days.2. Leaf decomposition rates were not significantly different when channelized streams were compared with natural woodland streams. In channelized streams the average decomposition rate was −0.0556±0.0337 (±S.D.) day−1 compared with −0.0457±0.0115 day−1 in natural woodland streams.3. There was significantly higher variation in leaf decomposition among the five channelized streams compared with the five natural streams (F–test, p<0.05). This was mainly due to extremely high decomposition rates in channelized streams colonized by emergent macrophytes.4. Alder decomposition rates were low in channelized streams without macrophytes (−0.0053 °day−1), intermediate in natural streams (−0.0087 °day−1), and high in channelized streams with macrophytes (−0.0136 °day−1).5. The shredder functional group ranged from 13 to 70% of the benthic community in the natural streams. Channelized streams had a more variable shredder population ranging from 0.5 to 80%. The highest values were found in channelized streams that had become colonized by macrophytes.6. There was a significant difference in total accumulated degree days between the channelized (256 °day) and natural woodland streams (209 °day). This is most likely an effect of drainage tiles contributing warmer groundwater to the channelized streams during fall.7. It is concluded that, contrary to the prevailing conceptual model of stream systems, decomposition rates and macroinvertebrate functions are not necessarily reduced in streams without riparian vegetation. The loss of the riparian canopy can stimulate emergent macrophytes which will provide autochthonous detritus for benthic communities. This will change benthic community structure and the life cycle strategies present.
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