Spectroscopy of low-spin states in 157Dy : Search for evidence of enhanced octupole correlations

CITATION: Majola, S. N. T., et al. 2019. Spectroscopy of low-spin states in 157Dy : Search for evidence of enhanced octupole correlations. Physical Review C, 100(6):034322, doi:10.1103/PhysRevC.100.034322.The original publication is available at https://journals.aps.org/prcLow-spin states of ¹⁵⁷Dy have been studied using the JUROGAM II array, following the ¹⁵⁵Gd (α, 2n) reaction at a beam energy of 25 MeV. The level scheme of ¹⁵⁷Dy has been expanded with four new bands. Rotational structures built on the [523]5/2⁻ and [402]3/2⁺ neutron orbitals constitute new additions to the level scheme as do many of the inter- and intraband transitions. This manuscript also reports the observation of cross I⁺ →(I–1) ⁻ and I⁻ →(I–1)⁺ E1 dipole transitions interlinking structures built on the [523]5/2⁻ (band 5) and [402]3/2⁺ (band 7) neutron orbitals. These interlacing band structures are interpreted as the bands of parity doublets with simplex quantum number s=–i related to possible octupole correlations.https://journals.aps.org/prc/abstract/10.1103/PhysRevC.100.034322Publisher's versio

First candidates for γ vibrational bands built on the [505] 11/2− neutron orbital in odd-A Dy isotopes:

Rotational structures have been measured using the Jurogam II and GAMMASPHERE arrays at low spin following the 155Gd(α,2n)157Dy and 148Nd(12C,5n)155Dy reactions at 25 and 65 MeV, respectively. We report high-K bands, which are conjectured to be the first candidates of a Kπ=2+γ vibrational band, built on the [505]11/2− neutron orbital, in both odd-A155,157Dy isotopes. The coupling of the first excited K=0+ states or the so-called β vibrational bands at 661 and 676 keV in 154Dy and 156Dy to the [505]11/2− orbital, to produce a Kπ=11/2− band, was not observed in both 155Dy and 157Dy, respectively. The implication of these findings on the interpretation of the first excited 0+ states in the core nuclei 154Dy and 156Dy are also discussed

β and γ bands in N = 88 , 90, and 92 isotones investigated with a five-dimensional collective Hamiltonian based on covariant density functional theory : vibrations, shape coexistence, and superdeformation

CITATION: Majola, S. N. T. et al. 2019. β and γ bands in N=88, 90, and 92 isotones investigated with a five-dimensional collective Hamiltonian based on covariant density functional theory: Vibrations, shape coexistence, and superdeformation. Physical Review C, 100(4). doi:10.1103/PhysRevC.100.044324.The original publication is available at https://journals.aps.org/prc/A comprehensive systematic study is made for the collective β and γ bands in even-even isotopes with neutron numbers N = 88 to 92 and proton numbers Z = 62 (Sm) to 70 (Yb). Data, including excitation energies, B(E0) and B(E2) values, and branching ratios from previously published experiments are collated with new data presented for the first time in this study. The experimental data are compared to calculations using a five-dimensional collective Hamiltonian (5DCH) based on the covariant density functional theory (CDFT). A realistic potential in the quadrupole shape parameters V (β,γ ) is determined from potential energy surfaces (PES) calculated using the CDFT. The parameters of the 5DCH are fixed and contained within the CDFT. Overall, a satisfactory agreement is found between the data and the calculations. In line with the energy staggering S(I) of the levels in the 2γ + bands, the potential energy surfaces of the CDFT calculations indicate γ -soft shapes in the N = 88 nuclides, which become γ rigid for N = 90 and N = 92. The nature of the 02 + bands changes with atomic number. In the isotopes of Sm to Dy, they can be understood as β vibrations, but in the Er and Yb isotopes the 02 + bands have wave functions with large components in a triaxial superdeformed minimum. In the vicinity of 152Sm, the present calculations predict a soft potential in the β direction but do not find two coexisting minima. This is reminiscent of 152Sm exhibiting an X(5) behavior. The model also predicts that the 03 + bands are of two-phonon nature, having an energy twice that of the 02 + band. This is in contradiction with the data and implies that other excitation modes must be invoked to explain their origin.https://journals.aps.org/prc/abstract/10.1103/PhysRevC.100.044324Publisher’s versio

The impact of agricultural mechanization on smallholder agricultural productivity: Evidence from Mnquma Local Municipality in the Eastern Cape Province

Smallholder agriculture is one of the imperative segments in the South African economy and it remains a vital sector for livelihood generation. Despite its numerous benefits and efforts, smallholder productivity has not improved as expected due to many underlying factors. This paper investigates factors influencing and the impact of agricultural mechanisation on smallholder agricultural production in Mquma Local Municipality located in the Eastern Cape Province. The study applied a descriptive survey research design. A stratified sampling procedure was used to gather information from 120 smallholder farmers using a semi-structured survey. Data collected were analysed using descriptive statistics, a Logistic Regression Model, and Propensity Score Matching. The results of the study reveal that about 90% of the smallholder farmers were using agricultural mechanisation for farming. The use of agricultural mechanisation has an impact on smallholder agricultural production. It ensured a proliferation in smallholder productivity, farm returns, and crop intensity. The study recommends that government and relevant stakeholders must develop effective agricultural access to credit by farmers as a strategy for increasing the adoption attitude to agricultural mechanization. The study suggests that reinforcement of the promotion of innovative technology adoption will have a crucial role in improving smallholder agriculture

Computer aided detection tool development for teaching chest radiograph pattern recognition to undergraduate radiography students

Abstract: Background: Medical imaging (MI) education has experienced a shift aligned with the advances in technology and the role played by radiographers in pattern recognition. This has led to increased use of technology-enhanced teaching and simulated learning approaches (e.g. computer-aided detection [CAD] tools) which also support the increasing requirement to develop pattern-recognition skills at undergraduate level. However, the development of these approaches need to be explored and planned carefully to be context-relevant. Aim: The aim of this study was to explore and describe the need for and capability of a CAD tool for teaching chest radiography pattern recognition in an undergraduate radiography programme. Setting: The setting was a university that offers MI education. Method: The study employed a qualitative descriptive design with an interpretive research paradigm. Purposive sampling was used to recruit information-rich participants for a focus group interview. Information-rich participants were considered to be those who were involved in teaching clinical skills, such as those required in pattern recognition, to radiography students. Data were transcribed verbatim and analysed in a step-by-step approach. Results: Three main themes emerged: (1) a structured approach to enhance implicit skills is critical in the CAD tool design; (2) an authentic tool which is able to simulate real-world experiences in image analysis is essential; and (3) a tool which encourages self-directed learning using a wide variety of pathological conditions would be ideal. Conclusion: The results of this study are essential in guiding radiography educators in designing CAD tools for teaching chest radiography pattern recognition

Phenotypes, endotypes and genotypes of atopic dermatitis and allergy in populations of African ancestry on the continent and diaspora

Atopic dermatitis is a complex inflammatory condition characterized by synergist interactions between epidermal and immune related genotypes, skin barrier defects and immune dysregulation as well as microbial dysbiosis. Ethnicity-specific variations in clinical presentation, immune endotypes and genetic susceptibility have been described in diverse populations. We summarize available data with specific consideration of AD in populations of African ancestry. Some highlights include the observation of AD lesions on extensor surfaces, lichen planus-like AD, prurigo type AD and follicular AD in African populations. In addition, a consistent absence of dominant filaggrin gene defects has been reported. The detection of normal filaggrin protein content in AD skin implicates the contribution of alternative mechanisms in the pathogenesis of AD in African patients. Markedly high IgE has been described in paediatric and adult African AD. While Th2, Th22 and Th17 activation in African AD skin shares the same direction as with other populations, it has been noted that the magnitude of activation is dissimilar. Reduced Th17 cytokines have been observed in the circulation of moderate to severe paediatric AD

Low-lying positive parity bands in

The structure of the low-lying positive parity bands in 162Yb has been studied at iThemba LABS, using the 150Sm(16O,4n)162Yb 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 $\gamma$-vibrational band. The first excited $0^{+}_{2}$ band and the even spin members of the $\gamma$-vibrational band exhibit a Landau-Zenner crossing. This crossing demonstrates that the significant signature splitting between the odd and even spin members of the $\gamma$ band is contributed to by band mixing

New collective structures in the

The 152Sm(16O, 5n)163Yb reaction at a beam energy of 93 MeV was used to study the excited states of 163Yb with the AFRODITE $\gamma$-ray spectrometer at iThemba LABS. The level scheme of 163Yb 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 [505]11/2- Nilsson orbital has been observed and is reported for the first time in this work. Additional new states in 163Yb were observed which all decay to the yrast band. Some of these states are placed in a sequence which is conjectured to be a $\gamma$ band involving a coupling with the i 13/2[642]5/2+ neutron orbital. The band structures are discussed with reference to Cranked Shell Model (CSM) calculations and a systematic comparison with the neighbouring nuclei