Introduction: South Africa is yet to introduce rubella-containing vaccines (RCV) into its routine immunization schedule. Selecting the target population when introducing RCV should take into account ...the ages of susceptible individuals in the population. We aimed to determine the seroprevalence of antibodies to rubella and characterize immunity gaps among individuals of all ages in South Africa.
Methods: We tested for rubella immunoglobulin G (IgG) antibodies with a commercial enzyme-linked immunosorbent assay. We used residual samples collected from 2016 through 2018 as part of the national measles surveillance program. We only tested samples that were negative for measles and rubella immunoglobulin M (IgM) and explored the association between rubella susceptibility (IgG negative) and predictor variables (year of sample collection, age, sex, and province of residence) using logistic regression analysis.
Results: We obtained results for 6057 records. Rubella susceptibility was highest among Individuals aged zero to 11 months (81.9%), followed by children 1 to 5 years old (71.5%), 6 to 10 y old (40.9%) and 11 to 15 y old (31.25) while the smallest proportion of susceptible individuals was among those 16 to 49 y old (19.9%). Females were less likely to be susceptible to rubella compared to males (OR = 0.79 (95%CI: 0.71-0.87), P < .001) in unadjusted analysis but this effect was not observed after adjusting for age and province. In multivariable logistic regression, age (OR = 6.24 (4.52-8.63), P < .001) and province of residence (OR = 0.97 (95%CI: 0.95-0.99), P = .01) were associated with rubella susceptibility.
Conclusion: In the absence of rubella vaccination in the Expanded Program on Immunization in South Africa, the bulk of individuals susceptible to rubella are children under 16 y old. About 20% of individuals 16 to 49 y old are susceptible to rubella. This susceptibility gap must be born in mind during RCV introduction.
Excited states in 98Ru were investigated using γ-ray spectroscopy following the β-decay of 98Rh, and via the 100Ru(p,t) reaction. Combining the results from the two experiments, two states were ...revised to have spin-parity of 4+ and subsequently assigned to the 02+ and “γ” bands, respectively. The observed structures in 98Ru are suggested to be deformed and rotational, rather than spherical and vibrational, and fit well into the systematics of these excitations in the Ru isotopes. The 02+ excitation is suggested as a shape coexisting configuration. This observation eliminates some of the last remaining candidates for nearly harmonic vibrational nuclei in the Z≈50 region. Beyond-mean-field calculations are presented that support shape coexistence throughout the Ru isotopes with N=52–62, and suggest a smooth evolution of the shapes.
A recently developed portable, on-line capability for γ-ray and conversion-electron spectroscopy, HIGH-TATRA is demonstrated with its application to the study of 183Hg → 183Au at ISOLDE. Key details ...of the low-energy level scheme of the neutron-deficient nuclide 183Au populated in this decay are presented. A broad energy germanium detector is employed to achieve this (the first-ever use of such a device in decay-scheme spectroscopy), by way of a combination of high-gain γ-ray singles spectroscopy and γ-γ coincidence spectroscopy. Further, by combining the γ-ray detectors with a liquid-nitrogen-cooled Si(Li) detector operated under high vacuum, conversion-electron singles and e-γ coincidences are obtained. These data lead to the determination of transition multipolarities and the location of a highly converted (E0 + M1 + E2) transition in the 183Au decay scheme, suggesting a possible new shape coexisting structure in this nucleus. Identification of new intruder and normal states fixes their relative energies in 183Au for the first time. New systematic features in the odd-Au isotopes are presented.
As part of a systematic study of the nuclear structure of the Ru isotopes, 98Ru was investigated via the β-decay of 98Rh at iThemba LABS, and the 100Ru(p, t) reaction at the Maier-Leibnitz ...Laboratory. The combined data results in significant revision of the previous spin assignments and clarification of the nature of levels in 98Ru, as well as providing insights into the evolution of the structures across the Ru isotopic chain.
New collective structures in the 163Yb nucleus Sithole, M. A.; Sharpey Schafer, J. F.; Majola, S. N. T. ...
The European physical journal. A, Hadrons and nuclei,
2019/10, Volume:
55, Issue:
10
Journal Article
Peer reviewed
.
The
152
Sm(
16
O, 5n)
163
Yb reaction at a beam energy of 93 MeV was used to study the excited states of
163
Yb with the AFRODITE
γ
-ray spectrometer at iThemba LABS. The level scheme of
163
Yb has ...been extended and new rotational bands established. The band based on the ground-state has been extended from a spin of 11/2
-
to spin 43/2
-
. A high-
K
band based on the neutron 50511/2
-
Nilsson orbital has been observed and is reported for the first time in this work. Additional new states in
163
Yb were observed which all decay to the yrast band. Some of these states are placed in a sequence which is conjectured to be a
γ
band involving a coupling with the
i
13/2
6425/2
+
neutron orbital. The band structures are discussed with reference to Cranked Shell Model (CSM) calculations and a systematic comparison with the neighbouring nuclei.
Low-lying positive parity bands in 162Yb Mdletshe, L.; Ntshangase, S. S.; Sharpey-Schafer, J. F. ...
The European physical journal. A, Hadrons and nuclei,
2018/10, Volume:
54, Issue:
10
Journal Article
Peer reviewed
.
The structure of the low-lying positive parity bands in
162
Yb has been studied at iThemba LABS, using the
150
Sm(
16
O,4n)
162
Yb fusion-evaporation reaction. A band built on the first excited
0
2
...+
state has been identified for the first time. In addition, we report new rotational levels that form the band structures of both the odd and even spin components of the
γ
-vibrational band. The first excited
0
2
+
band and the even spin members of the
γ
-vibrational band exhibit a Landau-Zenner crossing. This crossing demonstrates that the significant signature splitting between the odd and even spin members of the
γ
band is contributed to by band mixing.
Measurement of neutron production from an 18O target Ngcobo, P.Z.; Bark, R.A.; Buffler, A. ...
Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms,
02/2022, Volume:
513
Journal Article
Peer reviewed
Neutron yields and cross-sections from the bombardment, by protons of energies 30, 42, 54 and 66 MeV, on thin 18O water targets, and a 2.5 mm thick Li target, have been measured at 0∘ and 16∘, in ...addition to that of a stopping length 18O water target at 62 MeV. The results are compared with measured yields from beryllium targets and with FLUKA simulations.
With its unique combination of excellent timing properties and good energy resolution, LaBr3:Ce detectors have proven to be effective tool in gamma spectroscopy and in particular fast-timing studies. ...Eight 2” x 2” LaBr3:Ce detectors used in conjunction with the 16 channel all-digital waveform 500 MHz acquisition module, PIXIE-16 were commissioned at iThemba Laboratory for Accelerator Based Sciences, South Africa. The results presented here give insight of the performance of the 2” x 2” LaBr3 detectors when used in conjunction with a digital pulse processing (DPP) module and electronic read-out module. Initial commissioning experiments were done using radioactive sources, including 60Co, 152Eu and 67Ga. The detectors were then exposed to an in-beam environment using the AFRODITE array with targets 45Sc and 64Ni, with a proton beam energy of 27 MeV.
Abstract
As part of a systematic study of the nuclear structure of the Ru isotopes,
98
Ru was investigated via the β-decay of
98
Rh at iThemba LABS, and the
100
Ru(
p, t
) reaction at the ...Maier-Leibnitz Laboratory. The combined data results in significant revision of the previous spin assignments and clarification of the nature of levels in
98
Ru, as well as providing insights into the evolution of the structures across the Ru isotopic chain.
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