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Influence of preparation and processing routes on the activation and hydrogen sorption performance of hydrogen storage alloys based on TiFe intermetallic
No full textHydrogen storage alloys of the composition close to stoichiometric TiFe intermetallic were prepared by different routes including arc melting and several variations of induction melting in the in-situ formed magnesia crucible doped by CaZrO3 and Y2O3. As expected, the TiFe alloys could be fully hydrogenated only after performing several activation cycles at hard conditions including vacuum heating to 450–500 °C followed by exposure to pressurised hydrogen. At the same time, the addition of 2 wt% of mischmetal deoxidiser during induction melting results in softening the activation conditions. The best improvements were achieved when the alloy components (Fe, Ti) and the deoxidiser were loaded directly into the crucible before the melting. The improvements were mainly associated with the formation in the alloy of rare earth oxide deposits which break the continuity of the surface oxide layer inhibiting the hydrogenation. The activation performance of the induction-melted alloys was further improved by their ball milling in hydrogen, particularly, with an additive of 2 wt% of nickel nanoparticles deposited on a graphene-like material. The material processed by this way was characterised by fast hydrogen absorption without vacuum heating, even after short-term air exposure
Emotional social screening tool for school readiness (e3sr-r): adaptation into Afrikaans
No full textThe Emotional Social Screening Tool for School Readiness – Revised (E3SR-R) is a contextually sensitive and psychometrically sound measure developed to screen emotional-social competence in preschool learners in South Africa, a multilingual country. The original measure was constructed in English. This article reports on the translation of the E3SR-R into Afrikaans. A three-phase design was adopted. Phase 1: Independent reviewers evaluated the E3SR-R for conceptual validity. The Conceptual Construct Validity Appraisal Checklist was used to assess whether the E3SR-R was theoretically sound prior to adaptation. Phase 2 entailed translation of the E3SR-R. Reviewers used the Quality of Translation and Linguistic Equivalence Checklist to assess compliance with International Test Commission (ITC) guidelines. Phase 3 established content validity of the translation using a Delphi panel of 9 experts. The panel concluded within one round. Ethics clearance was granted by the University of the Western Cape. All applicable ethics principles were upheld. In Phase 1, a high level of inter-rater agreement confirmed that the E3SR had conceptual construct validity that supported adaptation. Phase 2 produced an Afrikaans translation. Raters had a high level of agreement that the adaptation complied with ITC guidelines. The Delphi panel concluded that the Afrikaans version demonstrated content validity. The Afrikaans translation of the E3SR-R was linguistically equivalent. Contribution: The study employed a rigorous methodology that underscored the importance of establishing conceptual construct validity, evaluating the translation process and establishing content validity in translation studies. Access to screening tools for emotional-social competence in pre-schoolers was expanded
Inactivation of Cyclotella meneghiniana to prepare biochar by in-liquid pulsed discharge plasma
No full textThe large-scale outbreaks of harmful algal blooms continue to impact river and lake ecosystems. Converting harmful algal blooms into algal biochar presents a novel approach. This work investigates the inactivation of Cyclotella meneghiniana (the dominant species in diatom blooms) to prepare biochar by in-liquid pulsed discharge plasma (LPDP). Under the conditions of a peak voltage of 30 kV and an electrode spacing of 7 mm, a 100 % inactivation ratio can be achieved within 20 min plasma treatment. The multiple physical and chemical effects generated by in-liquid pulsed discharge cause the cell structure destruction, chlorophyll-a content reduction, enzyme activity decrease, and malondialdehyde oxidative degradation leading to algal inactivation and biochar production. The obtained algal biochar has the advantages of a rich carbon content and a stable structure. This work provides a new technological option for resource utilization of algal blooms
Rights and responsibilities of unmarried fathers: A model for social workers
No full textThis study focused on the mediation practices of designated social workers (DSWs) during applications for parental responsibilities and rights by unmarried fathers in terms of Section 21 of the Children’s Act 38 of 2005. Designated social workers must direct the legal and emotional complexities, as well as the parental responsibilities and rights of unmarried fathers. It was evident from existing research that hegemonic masculinity influenced laws and the implementation of these laws.
The aim of the research was to develop a family mediation model for designated social workers to use during mediation with unmarried fathers and the unmarried mother of the child. The objectives of the research were: To explore and describe the mediation practices of social workers in the Department of Social Development, Western Cape (DSD), and Designated Child Protection Organisations (DCPOs) during the assessment of applications by unmarried fathers on parental responsibilities and rights; to explore and describe the factors that influence mediation social work practices in the DSD and DCPOs, during the application process of unmarried fathers for their parental responsibilities and rights and to develop a model for social workers in the DSD, Western Cape, and DCPOs, to address the applications of unmarried fathers for their parental responsibilities and rights within mediation.
The study applied a qualitative research approach with explorative and descriptive research designs. The study population comprised all DSWs working in the Western Cape for the DSD and DCPOs. The study sample consisted of ten DSWs from the various regions in the Western Cape and five key participants. The researcher used an adapted intervention design and development model to determine the cultural, procedural, and social factors which influenced the decisions of DSWs during their mediation practise. The researcher followed ethical considerations and ensured voluntary participation and confidentiality during the research. The research findings provided valuable insights to improve the involvement of unmarried fathers during mediation by using caring masculinity. The findings additionally revealed that the practices of DSWs were grounded in traditional theories on hegemonic masculinity, which emanated from the dominant patriarchal views of policymakers, the ruling government and legislatures. Most social workers came from a hegemonic masculinity stance where they would support the unmarried mother at all costs
Data driven neural network approaches for pricing options
No full textThis paper presents two data driven approaches, the purely data driven (PDD) and physics informed neural network (PINN) approach for solving asset pricing problems. The PDD approach relies purely on available data and does not require any governing partial differential equation (PDE) to solve a pricing problem. On the other hand, under the PINN approach, the pricing is done by solving a governing PDE. Both models are calibrated to observed market prices, and their implied volatilities are compared to those derived from market data and the classical Black–Scholes model. The absolute errors and maximum absolute errors metrics relative to observed implied volatilities and prices and the prices obtained from the classical Black–Scholes model were used in measuring the goodness-of-fit of the two proposed techniques. Several hyperparameter tuning techniques were employed to optimize the performance of the two methods. In addition, we analyze the probability density functions (PDFs) derived from each method and verify that they are valid by demonstrating positivity and proper normalization. Theoretical results, including propositions and theorems, are presented to establish conditions under which the PINN, trained using the Adam optimizer and initialized via the Xavier method, converges to an optimal solution, i.e., a set of trainable parameters that minimize the loss function. In further extensions, the PINN approach was applied to pricing European put options under a Heston stochastic volatility model (HSVM) model. While both methods exhibit competitive performance when calibrated, our empirical findings indicate that the PINN approach yields superior accuracy and stability
Telemedicine contraceptive counselling through whatsapp in South African abortion care: a mixed-methods acceptability study
No full textIntroduction: While telemedicine contraceptive counselling may enhance access and uptake, particularly in low-resource settings, the evidence for its acceptability as an alternative to in-person counselling remains limited. We therefore assessed the acceptability of PlanUrFam, a comprehensive WhatsApp-based contraceptive counselling tool, among women seeking abortion care in South Africa. Methods: We conducted a mixed-methods pilot study at two public health clinics. Women seeking abortion care (n = 31) used PlanUrFam for contraceptive counselling and were followed-up at two weeks (n = 28). The primary outcome was a composite measure acceptability, informed by the Theoretical Framework of Acceptability (TFA). The secondary outcome was choice of long-acting reversible contraception (LARC) and preference for future counselling. In-depth interviews with a nested subgroup (n = 8) explored experiences of the tool using the TFA and content analysis. Results: There was high acceptability (89%, n = 25/28) across framework domains. Qualitative results confirmed that PlanUrFam was acceptable, easy to use, understand and reduced judgement experienced in in-person care. Comprehensive information increased perceived confidence and agency in contraceptive decision-making. After using PlanUrFam, most participants chose LARC methods (64%, n = 18/28), chose a different contraceptive than previously used (96%, n = 27/28), and preferred either PlanUrFam alone (54%) or in combination with in-person counselling (36%) for future contraceptive care. Discussion: This pilot demonstrates high acceptability of PlanUrFam in abortion care and supported informed decision-making and choice of LARC. The effectiveness of PlanUrFam or similar interventions compared to standard care should be explored in randomised controlled trials measuring method initiation, continuation, recurrent pregnancy and abortion
An analysis of the laws which criminalise sex work in South Africa and the effects thereof
No full textThis thesis seeks to establish whether the current criminalisation regime followed by South Africa infringes the constitutional rights of black female sex workers. Black female sex workers are the focal point of this thesis as they are one of the most vulnerable groups in South Africa. Sex workers are one of South Africa’s most marginalised communities and are often plagued by injustices including gender-based violence and exploitation and are left with no legal recourse due to the illicit nature of their profession1. Those brave enough to seek the help of the South African Police Services (SAPS) or the healthcare system are rarely met with a safe environment and find themselves subjected to secondary abuse by those who are sworn to protect and serve.
Exploring the clinical workflow in pharmacogenomics clinics: an observational study
No full textBackground: Pharmacogenomics (PGx) is the future of healthcare and implementation is being driven by increasing evidence. Understanding the workflow in a PGx clinic provides insight into the development and implementation of PGx services. It considers the patient’s perspective, the role of the interprofessional team and the pivotal input of the pharmacist. Objectives: The purpose of this study was to describe the clinical workflow followed in selected PGx clinics. Methods: Four different sites that offer PGx clinical services (United States of America) were included. Qualitative data were collected through semi-structured interviews and observations providing valuable insights into the workflow followed in both community-based and hospital-based PGx clinics. Results: Although each setting differed, the processes were similar with setting-specific workflows and barriers. This study highlights the role of the pharmacist and the interprofessional team, the resources used for interpretation of PGx test results and the importance of patient and healthcare education. Conclusions: Understanding the workflow and the role of the interprofessional team in PGx is essential to ensure successful implementation and sustainable precision medicine practices in resource-limited settings
Behavioral addictions and cardiovascular health: a scoping review of the peer-reviewed primary research literature
No full textBackground: Most studies that have examined the association of addiction with cardiovascular diseases (CVDs) have been completed regarding substances. However, behavioral addictions may indirectly or directly negatively impact one’s health. We engaged in a scoping review on the associations of behavioral addictions (i.e., sex, exercise, love, Internet, shopping, gambling, and work) with cardiovascular health. We aimed to explore (1) the addictive behaviors addressed in the literature, (2) the study samples and country contexts, (3) the methods used, and (4) the associations found with CVD or its precursors. Methods: Using the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews checklist and following Arksey and O’Malley’s (2005) methodological framework, a search across the Web of Science, PubMed, 13 ProQuest databases, and Google Scholar yielded 59 primary research articles. Results: The majority of these studies inferred cardiovascular consequences emerging from engaging in these addictions, based on stresses induced, sedentary behavior involved, or proximal physiological data such as heart rate variability or electrocardiogram reactivity. However, the literature is quite weak in indicating that behavioral addictions lead to later cardiovascular events. Studies are also confounded by other variables (e.g., substance use disorders). No love addiction or shopping addiction-cardiovascular event studies were located, nor were the potential confounding effects of substitute addictions. Conclusions: Future longitudinal research and qualitative studies among older adults are needed to better discern the impact of behavioral addictions on cardiovascular health. For example, in studies that find cardiovascular effects such as high blood pressure, there is a need to try to discern whether the effects followed from addiction or preceded the addiction. In addition, studies are needed to discern whether behavioral addictions primarily impact cardiovascular health through social and reactivity consequences of engaging in the behaviors or merely indirectly through engagement in sedentary lifestyles
High-valence tungsten doping induces lattice expansion in Mo–Cu metal-organic framework-derived metal oxide-carbon composite (W@Mo–Cu MOF-MOCC) for enhanced urea electrooxidation catalysis
No full textIn this work, we report W@Mo–Cu metal-organic framework-derived metal oxide-carbon composite (W@Mo–Cu MOF-MOCC) as promising catalysts for the urea oxidation reaction (UOR), achieving a high current density of 10.0 mA cm−2 at 1.38 V. This performance surpasses that of Mo–Cu MOF-MOCC (10.0 mA cm−2 at 1.53 V), Cu-MOF-MOCC (10.0 mA cm−2 at 1.60 V), and Mo-MOF-MOCC (5.0 mA cm−2 at 1.68 V). Moreover, W@Mo–Cu MOF-MOCC exhibit a lower onset potential of 1.12 V vs. RHE and the lowest Tafel slope of 77.8 mV dec−1, indicating excellent catalytic activity comparable to various Ni-based catalysts. The enhanced UOR performance is attributed to three key factors: (i) doping with a high-valence metal (W) induces lattice expansion evidenced by the formation of (110) planes-in the Mo–Cu MOF-MOCC catalyst, which modulates the nanocrystalline interface, enhances grain boundary dynamics, and promotes the generation of active MoOOH species for efficient UOR (ii) the unique chicken-piece-like globular nanostructure provides a higher surface area (148.9 m2/g) and more active sites than other morphologies (e.g., rod-like Cu-MOF-MOCC, oval-like Mo-MOF-MOCC, and polyhedral Mo–Cu MOF-MOCC); and (iii) the synergistic interaction between W and the Mo–Cu interface enhances urea adsorption and oxidation at the catalyst surface. For practicality, a urine-mediated electrolysis cell was also developed, achieving a UOR current density of 10.0 mA cm−2 at 1.37 V in urine-containing wastewater, which is over 200 mV lower than in urea-free electrolyte. Furthermore, similar performance was observed in a 1.0 M NaOH + seawater electrolyte, reaching 10.0 mA cm−2 at 1.38 V. These findings demonstrate the potential of W@Mo–Cu MOF-MOCC as multi-functional, noble-metal-free, and Ni-free catalysts for green energy production and sustainable wastewater treatment, offering promising implications for environmental safety and resource recovery