The
γ
-ray strength function (
γ
SF) and nuclear level density (NLD) have been extracted for the first time from inverse kinematic reactions with the Oslo method. This novel technique allows ...measurements of these properties across a wide range of previously inaccessible nuclei. Proton–
γ
coincidence events from the
d
(
86
Kr
,
p
γ
)
87
Kr
reaction were measured at iThemba LABS and the
γ
SF and NLD in
87
Kr
was obtained. The low-energy region of the
γ
SF is compared to shell-model calculations, which suggest this region to be dominated by M1 strength. The
γ
SF and NLD are used as input parameters to Hauser–Feshbach calculations to constrain
(
n
,
γ
)
cross sections of nuclei using the TALYS reaction code. These results are compared to
86
Kr
(
n
,
γ
)
data from direct measurements.
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.
Gamma-ray line production cross sections from nuclear reactions induced by 30 - 200 MeV protons on natC and Mylar targets have been measured at the SSC facility of iThemba LABS. Results for the 4.439 ...and 6.129 MeV prominent lines of 12C and 16O of astrophysical concern are reported and discussed.
We report γ-ray spectra for the line observed at Eγ = 4.44 MeV in our previous experiments at iThemba LABS’ SSC facility using 30 - 200 MeV proton beams to irradiate a natC target. It is actually a ...complex composed of several lines of interest broadened by Doppler effect. In addition to the dominant 4.439 MeV line of 12C, two other lines at Eγ = 4.319 and 4.445 MeV assigned to 11C and 11B, respectively, are significant components of this complex. The analysis of its line shapes based on nuclear reaction models is the main topic of this contribution.
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.
Two nearly degenerate positive-parity bands with the πg9/22⊗νg9/2−1 configuration and three nearly degenerate negative-parity bands with the πg9/2(p3/2,f5/2)⊗νg9/2−1 configuration have been ...identified in 81Kr. They are interpreted as chiral doublet bands and pseudospin-chiral triplet bands, which is supported by the constrained covariant density functional theory and the multiparticle plus rotor model calculations. The present work reports two new chiral configurations πg9/22⊗νg9/2−1 and πg9/2(p3/2,f5/2)⊗νg9/2−1, and the first example of pseudospin-chiral triplet bands involving the π(p3/2,f5/2) pseudospin doublet.
Recently, the International Agency for Research on Cancer (IARC) Programme for the Evaluation of Carcinogenic Risks to Humans has been criticized for several of its evaluations, and also for the ...approach used to perform these evaluations. Some critics have claimed that failures of IARC Working Groups to recognize study weaknesses and biases of Working Group members have led to inappropriate classification of a number of agents as carcinogenic to humans.
The authors of this Commentary are scientists from various disciplines relevant to the identification and hazard evaluation of human carcinogens. We examined criticisms of the IARC classification process to determine the validity of these concerns. Here, we present the results of that examination, review the history of IARC evaluations, and describe how the IARC evaluations are performed.
We concluded that these recent criticisms are unconvincing. The procedures employed by IARC to assemble Working Groups of scientists from the various disciplines and the techniques followed to review the literature and perform hazard assessment of various agents provide a balanced evaluation and an appropriate indication of the weight of the evidence. Some disagreement by individual scientists to some evaluations is not evidence of process failure. The review process has been modified over time and will undoubtedly be altered in the future to improve the process. Any process can in theory be improved, and we would support continued review and improvement of the IARC processes. This does not mean, however, that the current procedures are flawed.
The IARC Monographs have made, and continue to make, major contributions to the scientific underpinning for societal actions to improve the public's health.
Objectives
The aim of this study was to quantify loss to follow‐up (LTFU) in HIV care after delivery and to identify risk factors for LTFU, and implications for HIV disease progression and subsequent ...pregnancies.
Methods
We used data on pregnancies within the Swiss HIV Cohort Study from 1996 to 2011. A delayed clinical visit was defined as > 180 days and LTFU as no visit for > 365 days after delivery. Logistic regression analysis was used to identify risk factors for LTFU.
Results
A total of 695 pregnancies in 580 women were included in the study, of which 115 (17%) were subsequent pregnancies. Median maternal age was 32 years (IQR 28–36 years) and 104 (15%) women reported any history of injecting drug use (IDU). Overall, 233 of 695 (34%) women had a delayed visit in the year after delivery and 84 (12%) women were lost to follow‐up. Being lost to follow‐up was significantly associated with a history of IDU adjusted odds ratio (aOR) 2.79; 95% confidence interval (CI) 1.32–5.88; P = 0.007 and not achieving an undetectable HIV viral load (VL) at delivery (aOR 2.42; 95% CI 1.21–4.85; P = 0.017) after adjusting for maternal age, ethnicity and being on antiretroviral therapy (ART) at conception. Forty‐three of 84 (55%) women returned to care after LTFU. Half of them (20 of 41) with available CD4 had a CD4 count < 350 cells/μL and 15% (six of 41) a CD4 count < 200 cells/μL at their return.
Conclusions
A history of IDU and detectable HIV VL at delivery were associated with LTFU. Effective strategies are warranted to retain women in care beyond pregnancy and to avoid CD4 cell count decline. ART continuation should be advised especially if a subsequent pregnancy is planned.
PDF
