16918 research outputs found
Sort by
The Three Hundred project: gas properties outside of galaxy clusters with the WHIM contribution and detection
No full textWe investigate the physical properties and detectability of warm-hot intergalactic medium (WHIM) gas with temperatures in the range 105 < T < 107 K around galaxy clusters using simulated galaxy clusters from THE THREE HUNDRED project. From our simulations with different input physics (GIZMO-SIMBA and GADGET-X), we consistently found that the median gas temperature, as a function of the radial distance from cluster centres, decreases to the WHIM upper bound, ∼107 K, at ∼2 × R200c. Meanwhile, the WHIM mass fraction increases with radius until ∼3 × R200c, where it plateaus slightly above 70% for both simulations at all investigated redshifts. By simulating X-ray emissions from all gas components, we found that the WHIM contribution at the soft X-ray band (0.2–2.3 keV) also increases with radius but eventually plateaus at larger distances. The differences between the two simulations become more pronounced at higher redshifts and larger radii, indicating that the WHIM observation can be used to constrain baryon models. After accounting for observational effects, primarily by removing (sub)halos, we predict that the signal-to-noise ratio of the X-ray signal obtained by stacking the eRASS1 galaxy cluster catalogue will be ∼6.4 for GIZMO-SIMBA and ∼20.8 for GADGET-X
Community perceptions on the impact of education in reducing poverty: case of Vrededorp, Gauteng.
No full textEducation is a vital instrument for poverty alleviation, but its usefulness in marginalised populations is limited by societal barriers. In South Africa's disadvantaged communities, historical legacies of apartheid and persisting socioeconomic inequities have hindered the potential of education to uplift individuals from poverty, as suggested by human capital theory. This has affected how community members perceive the relationship between education and poverty reduction. Given this background, the study aims to examine the community’s perceptions on the impact of education in reducing poverty: Case of Vrededorp, Gauteng. The study uses a mixed-methods approach, consisting of a standardised questionnaire survey and in-depth interviews to get insight into the community’s perceptions, opinions and experiences concerning education and poverty reduction. The study results suggest a contradictory narrative: while education is viewed as a road to economic mobility, its impact is hampered by inadequate school infrastructure, insufficient resources and high unemployment rates among educated people
An exploration of female educational outcomes in South Africa over the nineteenth century
No full textThe study of female education, especially in South Africa during the 19th century, has been an understudied area of historical economic research. This thesis will aim to fill this gap by investigating whether gender parity existed between male and female educational outcomes. Using historical data from the Western Cape Archives Records Service and Cape Colony Census data, the educational outcomes of males and females will be compared and discussed. This thesis highlights the importance of female human capital development for economic growth. During British rule in 19th-century South Africa, Missionary activities proliferated. Mission schools provided education to mainly Indigenous and Coloured communities. The Missionary impact expanded with government aid but also reinforced racial segregation in schooling. In the 19th century, there were significant changes in the labour market, influencing educational access and gendered roles into the 20th century. The regression analysis of the late 19th century highlighted that Coloured females surpassed Coloured males in attendance rates. White males slightly surpassed White females. The analysis studied the impact of average attendance, school order ratios and total teachers on the enrolment of males and females. The early 20th century data analysis showed the same trend (Coloured females surpassing males, while White males surpassed females) for literacy rates. Coloured females surpassed Coloured males in terms of the ability to read, while White males slightly surpassed White females in terms of literacy. These confounding trends indicate a need for further research to understand these unexpected gender dynamics
Electrochemical analysis of solvothermally synthesized MoS2 nanostructures for high performance supercapacitor
No full textThis study investigates the influence of different solvents, including ethylene glycol (EG), dimethylformamide (DMF) and water, on the structure and electrochemical properties of MoS2 synthesized via a single-step pot synthesis technique. These solvents facilitate the formation of MoS2 nanostructures with diverse dimensions. The synthesized material was analyzed using XRD, FTIR, Raman spectroscopy, FE-SEM and BET analysis. The hierarchical microflower structure of MoS2, with exfoliated edge-enriched nanosheets, exhibited the highest specific capacitance of 428 F g−1 at 1 mV s−1 and 280 F g−1 at 1 A g−1 when synthesized using water as a solvent, surpassing the results achieved with other solvents. The MoS2 nanostructure-based symmetric supercapacitor achieved an energy density of 7.5 Wh kg−1, a power density of 1980 W kg−1 and retained ∼95 % capacitance after 1000 cycles at 2 A g−1, highlighting its potential for future applications with exceptional stability and durability
Ccu2pdsnse4 and cu2pdsn(s,se)4 palladium-substituted kesterite nanomaterials for thin-film solar cells
No full textKesterites are being studied intensively as sustainable absorber materials for solar cell development. However, elements such as Zn and Cu exhibit antisite defects that function as charge traps and recombination centers that affect the light absorption and carrier transport efficiencies of kesterite solar cells. The substitution of Zn or Cu with other metals is one of the strategies used to improve the photovoltaic performance of kesterites. This study focuses on the preparation and photovoltaics of Cu2PdSnSe4 (CPTSe) and Cu2PdSn(S,Se)4 (CPTSSe) kesterite nanoparticles (containing Pd instead of Zn) by a modified solvothermal (polyol) microwave synthesis method. The nanomaterials exhibited a tetragonal kesterite crystal structure with polydispersed morphology and average crystallite sizes of 22 and 17 nm for CPTSe and CPTSSe, respectively. DAMMIF ab initio analysis of the small-angle X-ray scattering data determined the shape of CPTSe and CPTSSe nanomaterials to be ellipsoidal. Ultraviolet-visible (UV-vis) spectroscopy revealed red-shift absorption properties, with bandgap energy values of 1.13 eV (CPTSe) and 1.20 eV (CPTSSe), thereby making them suitable light absorber materials for photovoltaic applications. Photoluminescence spectroscopy characterization confirmed the attenuation of defect concentrations in CPTSe and CPTSSe compared to the Zn analogue, which positively impacts the charge-carrier transport and recombination properties. A preliminary test of the materials in superstrate photovoltaic cell devices yielded power conversion efficiency values of 1.32% (CPTSe) and 3.5% (CPTSSe). The CPTSe- and CPTSSe-based photovoltaic devices maintained ∼70% mean open-circuit voltage (Voc), which is a significant improvement over the ∼20% Voc retained by Zn-based kesterites after 24 days
Abortion in South-Africa: does a liberal legislation really impact safe access and use?
No full textThe World Health Organization (WHO) considers comprehensive abortion care as part of their essential healthcare service package, which includes the provision of information, abortion management, and post-abortion care. The WHO estimated that globally, 45% of all induced abortions were unsafe, and it noted that nearly half of all the abortions occurred under the least safe circumstances in Africa. Abortion has been legal in South Africa since the implementation of the Choice of Termination of Pregnancy (CTOP) Act (No. 92 of 1996), which was a significant departure from the country’s previously restrictive abortion laws. While the CTOP Act (1996) has made provision for access to safe abortion services and pre and post-abortion counselling, this has not been effectively implemented into effective service delivery. It’s estimated that between 52% and 58% of abortions take place in informal medical settings, and that only 7% of the public health facilities in South Africa were performing abortion services in 2017. The WHO noted that the lack of access to safe, affordable, timely, and respectful abortion care, and the stigma associated with abortion pose risks to women’s physical and mental well-being throughout the life-course. The aim of this paper was to explore how women in South Africa experience and cope with induced abortion. Additionally, this research looks at how religion, culture and stigma, impact abortion and mental health post-abortion of South African’s women. This study utilises data from the latest South African Demographic and Health Surveys (SADHS), in 2016, which includes data from 8514 women aged 15-49 years. This study highlights the need for more data and research related to challenges and experiences of South African women around mental health and the nature of abortion within the country. In this interview conducted by Professor Jean-Pierre Bouchard, population analysts Robynn Ashely Hera and Siposethu Nojoko together with demographer Professor Nancy Stiegler from the University of the Western Cape discuss safe and unsafe abortion incidence and access and the psychological effects thereof
Elemental analysis of nail clippings retrieved from farmers using x-ray fluorescence spectrometry
No full textNails are considered suitable biological materials for diagnosing diseases and biomonitoring for human exposure to metals by measuring trace elements levels. Human fingernail samples were collected from volunteers from the Gezira region, Sudan, samples were measured and studied for their elemental content using the X-ray fluorescence (XRF) method, and the data was analysed by PyMca software and SPSS statistical analysis. The data analysis revealed very high concentrations of toxic elements such as Zn, Ni, Pb, Cd, Sr, As, and Se. A comparison was made with published data from different populations. The goal of the current investigation was to evaluate the levels and patterns of trace and toxic elements in the fingernails. Differences and variations in concentrations for the samples were investigated and discussed
Protest action
No full text34 Images in this collection involve elements of protest. There are marches and gatherings and full-on political rallies!
We need your help
Do you know any of the people in these photos? Or maybe the events taking place? We are interested in any information directly related to any of these photographs.
Please browse these images and if you see yourself (or anyone you are related to or anyone you think may know anything) or remember any information about the time place or circumstances surrounding these images and send an email to [email protected] with any information
Leveraging remote sensing for optimised national scale agricultural water management in South Africa
No full textAgriculture remains a critical water resources consumer in arid regions, globally, including southern Africa. The intensity of consumption, however, varies significantly depending on the adopted watering method (i.e., rainfed or irrigated) and agricultural region. Efficient agricultural water management hinges on effectively monitoring Crop Water Use (CWU) and Crop Water Productivity (CWP). This study, thus, leveraged Moderate Resolution Imaging Spectroradiometer (MODIS) remotely sensed data in estimating the spatio-temporal variations of CWP and CWU across irrigated and rainfed croplands in diverse South African agricultural regions between 2017 and 2022. The results showed that rainfed croplands had higher CWU in agricultural regions dominated by grains (150 mm/yr) and cattle (160 mm/yr), while irrigated croplands exhibited the highest CWU in agricultural regions with sheep rearing (175 mm/yr) and subsistence agricultural activities (160 mm/yr). However, there were no significant differences (p > 0.05) in overall CWU across all the agricultural regions. Irrigated croplands generally had higher annual CWP (>0.002 kg/mm3/yr), while rainfed croplands consistently showed low CWP especially in forestry (0.001 kg/mm3/yr) and sugar (0.0012 kg/mm3/yr) agricultural regions. There were also no significant differences in average CWP between irrigated and rainfed croplands (p > 0.05). This study demonstrates the effectiveness of national-scale remotely sensed data in monitoring the spatiotemporal variations of CWP and CWU in South Africa. The results can be used to tailor strategies to specific agricultural regions and crop types and optimise water use efficiency. This would contribute significantly to sustainable national-scale agricultural water management in South Africa
Re-conceptualizing trafficking-in-persons victimization using latent class analysis: Results from a community study in Cape Town, South Africa
No full textThe impact of human trafficking upon the lives and livelihoods of those subjected to exploitative and illegal labor and commercial sex practices includes violence and threats of violence, deleterious health and mental health sequelae, and social and economic marginalization. Global estimates of human trafficking’s prevalence are elusive given that it is shrouded in secrecy and often affects subgroups with little voice of their own, such as migrants and child abuse victims. The difficulty of reaching a clandestine population is complicated by the lack of standardized definitions and culturally responsive assessments to identify victims and route them to appropriate care. This gap in knowledge persists on the African continent as elsewhere in the world. An interdisciplinary, international research team thus launched a study to estimate the prevalence of human trafficking using a computational algorithm in the Western Cape of South Africa. In this paper, we use latent class analysis to identify and empirically categorize 652 individuals at risk for human trafficking based on their response to two sets of indicators for human trafficking experiences. Our findings revealed three distinct subtypes ranging from very high risk of exploitation to relatively low risk. Experiences of violence, health and mental health concerns, and substance abuse were commonplace in this high-risk sample. A modified screening tool based on domains of trafficking identified by the inaugural Prevalence Reduction Innovation Forum (PRIF) was most robust in identifying and classifying victims. We conclude by calling for a shift from a binary prosecutorial definition to a dimensional approach of identifying trafficking, guided by the understanding that such risks exist on a spectrum influenced by one’s experience of human trafficking exploitation, and behavioral and social environment