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| 2. |
- Döring, J., et al.
(författare)
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Band terminations in the valence space of 86Zr
- 2000
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Ingår i: Physical Review C - Nuclear Physics. - 0556-2813. ; 61:3, s. 343101-343106
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Tidskriftsartikel (refereegranskat)abstract
- High-spin states in 86Zr up to 30+ and 27- were observed via the 58Ni(32S,4p) reaction at 135 MeV beam energy using the combined GAMMASPHERE and MICROBALL systems. Calculations performed with the configuration-dependent shell-correction approach show that these states are built from six g9/2 neutrons and at most four protons excited from the p1/2,p3/2,f5/2 subshells to the g9/2 subshell at small deformation. The highest observed states at 27- and 30+ are interpreted as band-terminating states with the latter having the highest spin available in the valence space for 86Zr.
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| 3. |
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| 4. |
- Rodriguez, W., et al.
(författare)
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High spin states of the normally deformed bands of y 83
- 2019
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Ingår i: Physical Review C. - 2469-9985. ; 100:2
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Tidskriftsartikel (refereegranskat)abstract
- Level lifetime and side-feeding time measurements were performed on the excited states of the normally deformed bands of Y83 using the Doppler-shift attenuation method (DSAM). The high spin states of Y83 were populated using the fusion-evaporation reaction Ni58(S32,α3p)Y83 at 135 MeV. Twenty-two level lifetime and side-feeding times were determined in most of the cases by comparing the line shapes gated with transitions above and below the state under study. Quadrupole moments determined from lifetime measurements are in the range 1.1-3.1 eb, and are similar to the ones found for some of the neighboring nuclei. The measured side-feeding times were compared with predictions made by simulations carried out with the Gammapace code. The results were in agreement with the experimental values by assuming reduced transition probabilities of the collective transitions in the continuum region, lying in the range 40-80 W.u. The discrete excited states were studied with paired cranked Nilsson-Strutinsky-Bogoliubov (CNSB) calculations carried out for the first time for an A≈80 nucleus. Unpaired cranked Nilsson-Strutinsky (CNS) calculations were used to specify configurations and study the band crossings. The measured |Qt| values show a general agreement with CNSB calculations. Cranked shell model analysis evinced that the smallest quadrupole moment appears at the sharpest band crossing of the bands studied and CNSB calculations show an increase of the deformation thereinafter.
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| 5. |
- Rudolph, Dirk, et al.
(författare)
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Shell-model Influence in the Rotational Nucleus 86Mo
- 1996
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 54:1, s. 117-124
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Tidskriftsartikel (refereegranskat)abstract
- High-spin states in Mo-86 were studied by means of the fusion evaporation reaction Ni-58(S-32,2p2n) Mo-86 at 135 MeV beam energy. Charged-particle-gamma gamma and -gamma gamma gamma coincidences recorded with the early implementation of the GAMMASPHERE array and the MICROBALL charged-particle detection system were used to largely extend the level scheme of the T-tau=1 nucleus Mo-86 to a possible spin of I=24h at 13 MeV excitation energy. The excitation scheme is compared to neighboring nuclei. There is evidence for enhanced shell-model influence in the 4 quasiparticle region (I=12-16h). The observed (pi=+,alpha=0) sequence at spin I greater than or equal to 16 h appears to be associated with a triaxial collective rotational band. This interpretation is supported by calculations within the configuration-dependent shell-correction approach with the cranked Nilsson potential.
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| 6. |
- Cardona, R., et al.
(författare)
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High-spin structure of normal-deformed bands in 84Zr
- 2003
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Ingår i: Physical Review C - Nuclear Physics. - 0556-2813. ; 68, s. 1-024303
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Tidskriftsartikel (refereegranskat)abstract
- The reaction 58Ni(32S, α2p) at E lab= 135 MeV was used to populate high-spin states in 84Zr. The complete GAMMASPHERE and MICROBALL arrays were used to obtain clean γ- γ- γ line shapes to be analyzed by the Doppler shift attenuation method and to determine 27 lifetimes in the ground-state band and in two excited bands. Side-feeding times were also measured by comparing the line shapes gated with transitions above and below the state under study. The deduced electric quadrupole moments for the ground-state band are consistent with a very slow reduction with frequency with values ranging between 2.4(3) and 2.0(1)e b. The negative-parity bands feature also an approximate constancy of quadrupole moment with values similar to those in the ground-state band. Cranking calculations agree with this behavior in both parity bands and suggest an interpretation of the upper states in the ground-state band as part of a very slowly terminating band. Shell-dependent cranked Nilsson calculations explain a fourth γ cascade as pertaining to a noncollective structure terminating at I = 20+.
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| 7. |
- Cooper, M. W., et al.
(författare)
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New γ transitions in 27Na from 14C on 14C
- 2001
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Ingår i: Nuclear Physics A. - 0375-9474. ; 682:1-4, s. 131-135
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Tidskriftsartikel (refereegranskat)abstract
- The neutron rich 27Na was studied at Florida State University using the 14C(14C,p) reaction at 22 MeV. The 14C target was 0.28 mg/cm2 thick. γ-γ and particle-γ, coincidences were measured using 2 four-crystal clover detectors, 7 Compton-suppressed HPGe detectors, and a particle detector telescope at 0°. The 1757, 1823, and 2219 keV transitions are likely yrast transitions in 27Na. Based on systematics of neighboring nuclei, the first two lines probably arise from the decays of the 7/2+ and 9/2+ states. The results will be discussed in terms of both the shell model and the cranked Nilsson-Strutinsky rotational model.
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| 8. |
- Foster, R. A., et al.
(författare)
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Structural elucidation of the O-antigen of the Shigella flexneri provisionalserotype 88-893 : structural and serological similarities with S. flexneri provisional serotype Y394 (1c)
- 2011
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Ingår i: Carbohydrate Research. - : Elsevier BV. - 0008-6215 .- 1873-426X. ; 346:6, s. 872-876
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Tidskriftsartikel (refereegranskat)abstract
- The structure of the repeating unit of the O-antigen polysaccharide from Shigella flexneri provisional serotype 88-893 has been determined. 1H and 13C NMR spectroscopy as well as 2D NMR experiments were employed to elucidate the structure. The carbohydrate part of the hexasaccharide repeating unit is identical to the previously elucidated structure of the O-polysaccharide from S. flexneri prov. serotype Y394. The O-antigen of S. flexneri prov. serotype 88-893 carries 0.7 mol O-acetyl group per repeating unit located at O-2 of the 3-substituted rhamnosyl residue, as identified by H2BC and BS-CT-HMBC NMR experiments. The O-antigen polysaccharide is composed of hexasaccharide repeating units with the following structure: →2)-α-l-Rhap-(1→2)-α-l-Rhap-(1→3)-α-l-Rhap2Ac-(1→3)[α-d-Glcp-(1→2)-α-d-Glcp-(1→4)]-β-d-GlcpNAc-(1→. Serological studies showed that type antigens for the two provisional serotypes are identical; in addition 88-893 expresses S. flexneri group factor 6 antigen. We propose that provisional serotypes Y394 and 88-893 be designated as two new serotypes 7a and 7b, respectively, in the S. flexneri typing scheme.
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| 9. |
- Sperling, L, et al.
(författare)
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How to identify twins at low risk of spontaneous preterm delivery
- 2005
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Ingår i: Ultrasound in Obstetrics & Gynecology. - : Wiley. - 1469-0705 .- 0960-7692. ; 26:2, s. 138-144
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Tidskriftsartikel (refereegranskat)abstract
- Objective The aim of this study was to evaluate transvaginal sonograpbic assessment of cervical length at 23 weeks as a screening test for spontaneous preterm delivery in order to define a cut-off value that could be used to select twin pregnancies at low risk of spontaneous preterm delivery. Methods In a prospective multicenter study of 383 twin pregnancies included before 14 + 6 weeks a cervical scan with measurement of the cervical length was performed at 23 weeks' gestation. The results were blinded for the clinicians if the cervical length was >= 15 mm. The rates of spontaneous delivery at different cut-off levels of cervical length were determined. Results Eighty-nine percent of the twins had dichorionic placentation and 58% were conceived after assisted reproduction. The rate of spontaneous preterm delivery was 2.3% (1.5% for dichorionic (DC) and 9.1% for (MC) monochorionic twins) before 28 weeks and 18.5% (17.1% for DC and 29.5% for MC twins) before 35 weeks. The screen-positive rate was 5% for a cervical length <= 20, 7-8% at <= 25, 16-17% at <= 30 and 34-48% at <= 35mm depending on chorionicity. The false-negative rate (1 - negative predictive value) ranged from 1.2% at 28 weeks to 18.6% at 35 weeks for all twins. Receiver-operating characteristics curves showed that the sensitivity increased with declining gestation I age with cut-off levels of highest accuracy at 21 mm for 28 weeks and 29 mm for 33 weeks. Conclusions Cervical length measurement at 23 weeks of gestation is a good screening test for predicting twins at low risk of preterm and very preterm delivery, especially in DC twins. The present results suggest that a cut-off of 25 mm should be recommended.
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| 10. |
- Sun, H., et al.
(författare)
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New Band Structures and an Unpaired Crossing in 78Kr
- 1999
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 59:2, s. 655-664
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Tidskriftsartikel (refereegranskat)abstract
- High-spin states in Kr-78 were studied using the Ni-58(Na-23,3p) reaction at 70 MeV and the Ni-58(Si-23,alpha 4p) reaction at 130 MeV. Prompt gamma-gamma coincidences were measured using the Pitt-FSU detector array and the GAMMASPHERE-MICROBALL array. Results from these experiments have led to 26 new excitation levels, some of which have been grouped into 3 new bands. Spins were assigned based on directional correlations of oriented nuclei. Two of the new negative-parity bands appear to form a signature-partner pair based on a two-quasineutron structure, in contrast to the previously known two-quasiproton negative-parity bands. A forking has been observed at the 24(+) state in the yrast band, which calculations suggest may result from an unpaired crossing. The available evidence suggests oblate shapes in the yrast band coexist with prolate shapes in the negative-parity bands. [S0556-2813(99)04602-6].
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