Embedding motivation in the self-directedness of first-year teacher students

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An assessment of coastal vulnerability for the South African coast

Coastal vulnerability is the degree to which a coastal system is susceptible to, or unable to cope with, adverse effects of climate change. One of the most widely used methods in assessing risk and vulnerability of coastlines on a regional scale includes the calculation of vulnerability indices and presenting these results on a vulnerability map. These maps can assist coastal managers, planners, landowners and stakeholders identify regions of greater risk to coastal hazards and ultimately better inform mitigation and development strategies.This paper discusses the creation of a coastal vulnerability map for South Africa. The criteria used included elevation to chart datum, beach width, tidal range, wave height, geology, geomorphology, anthropogenic activities, distance to 20m isobaths and relative sea level change. The values of these parameters were divided into classes and the various classes ranked on a scale of 1 (very low vulnerability) to 5 (very high vulnerability) using examples from literature and expert knowledge. The layers were combined using the spatial overlay (map algebra) technique to create the final map. The results highlight the most vulnerable areas along the coastlines as the areas surrounding the City of Cape Town (the west coast) and the regions close to East London and Port St. Johns on the east coast. This can be mainly attributed to the type of geology and the anthropogenic activities in these areas

Calibration artefacts in radio interferometry. I. Ghost sources in WSRT data

This work investigates a particular class of artefacts, or ghost sources, in radio interferometric images. Earlier observations with (and simulations of) the Westerbork Synthesis Radio Telescope (WSRT) suggested that these were due to calibration with incomplete sky models. A theoretical framework is derived that validates this suggestion, and provides predictions of ghost formation in a two-source scenario. The predictions are found to accurately match the result of simulations, and qualitatively reproduce the ghosts previously seen in observational data. The theory also provides explanations for many previously puzzling features of these artefacts (regular geometry, PSF-like sidelobes, seeming independence on model flux), and shows that the observed phenomenon of flux suppression affecting unmodelled sources is due to the same mechanism. We demonstrate that this ghost formation mechanism is a fundamental feature of calibration, and exhibits a particularly strong and localized signature due to array redundancy. To some extent this mechanism will affect all observations (including those with non-redundant arrays), though in most cases the ghosts remain hidden below the noise or masked by other instrumental artefacts. The implications of such errors on future deep observations are discussed.Comment: 19 pages, 15 figures, submitted to MNRA

Prevalence of a postoperative troponin leak in patients with cardiac risk factors undergoing knee and hip arthroplasty in a South African population

Background. Patients undergoing arthroplasty may have comorbidities that put them at risk of myocardial injury after non-cardiac surgery (MINS). MINS, a new clinical concept that has a different pathophysiology from conventional myocardial infarction, is related to a supply-demand mismatch ischaemia in the perioperative setting. MINS is often a silent event, and the diagnosis relies on cardiac biomarker testing such as troponin T. The incidence is estimated at 40%, with a fourfold increase in morbidity and mortality risk 1 year post surgery.Objectives. To determine the prevalence of postoperative troponin leak in a single-centre arthroplasty unit in patients with various cardiac risk factors undergoing hip or knee arthroplasty and investigate the differences in troponin T levels between comorbidities and different types of arthroplasty, i.e. total hip replacement (THR), total knee replacement (TKR) and neck of femur (NoF) fracture hip replacement.Methods. A prospective, cross-sectional study of patients with one or more cardiac risk factors undergoing replacement surgery was conducted from October 2017 to April 2018. Troponin levels of all included patients were recorded on days 1 and 3 post surgery using a high-sensitivity cardiac troponin T assay (Roche hs-cTnT). A level of >15 ng/L is considered abnormal and termed a positive troponin leak, while >100 ng/L is considered suspected acute coronary syndrome (ACS).Results. One hundred and sixty patients (n=66 THR, n=55 NoF hip replacement, n=39 TKR) were included. Sixty-eight patients (42%) had a positive troponin leak, and in 6 of these cases ACS was suspected. The highest prevalence of troponin leak was recorded in patients undergoing NoF hip replacement (62%), followed by TKR (46%) and then THR (24%). Sixty-two patients (38%) had positive troponin levels on day 1 and 53 patients (33%) had positive levels on day 3. Important patient cardiac risk factors were identified in the presence of a positive troponin leak, with ischaemic heart disease, hypertension, diabetes, renal disease, age >65 years and atrial fibrillation being statistically most likely.Conclusions. Postoperative troponin surveillance is an inexpensive and reliable way to identify patients at risk of MINS and subsequently enhance early detection, medical optimisation and referral strategies. Simple interventions may improve outcomes and contribute to lower ACS rates and the timeous prevention of other complications. The prevalence of MINS in orthopaedic-specific patients in South Africa (SA) and other resource-constrained developing countries is unknown. Our finding of 42% positive troponin leaks raises awareness of this issue, and we recommend routine postoperative troponin surveillance for all arthroplasty units in SA.

Bacterial keratitis and corneal scarring secondary to cosmetic contact lens wear

Objective: To report three cases of bacterial keratitis and corneal scarring secondary to cosmetic contact lens wear. Design: Case series. Setting: Groote Schuur Hospital, Cape Town. Result: There is an increased risk of bacterial keratitis with the use of contact lenses. This is more likely to occur in people who are not regular contact lens wearers and who do not practice adequate contact lens care. Conclusion: The marketing and distribution of cosmetic contact lenses should be regulated, and people should be educated in correct contact lens care before purchase

The relationship between obesity, leptin, adiponectin and the components of metabolic syndrome in urban African women, Free State, South Africa

Objectives: Obesity prevalence is increasing worldwide. In South Africa, older and urbanised African women have significantly higher rates of obesity. Limited information is available on the relationship between anthropometric parameters, adipokines and metabolic health status of African women. This study investigated the relationship between obesity, adipokines and the components of metabolic syndrome in urban African women.Methods: This study included 135 urban African women that were 26–63 years of age, identified with metabolic syndrome in the urban leg of the Assuring Health for All in the Free State (AHA-FS) study. To establish anthropometric status, the following measures were taken: body weight, height and waist circumference. Blood was drawn to determine leptin, adiponectin levels and metabolic status.Results: Adiponectin levels in obese women were significantly decreased compared to normal weight women. Leptin levels and leptin:adiponectin ratios (L:A) were increased in the obese group compared to the overweight and normal weight groups. Leptin and L:A showed strong positive correlations with body mass index and waist circumference. Adiponectin levels decreased as the number of components of metabolic syndrome increased. The L:A ratio was significantly lower in women with elevated triglycerides and significantly higher in women with elevated blood glucose levels. Adiponectin levels were significantly lower in women with elevated blood glucose.Conclusion: This study confirms the inverse relationship between adiponectin and leptin with increased body adiposity. Results indicate that waist circumference, fasting blood glucose and triglyceride levels are the metabolic syndrome components most closely associated with altered adiponectin and leptin levels and L:A in urban African women with metabolic syndrome.Keywords: adipokines, adiponectin, components of metabolic syndrome, leptin, L:A ratio, obesit

Risk factors for atherosclerosis - can they be used to identify the patient with multisystem atherosclerosis?

Risk factors are often used in preventive care programmes to identify the patient at particular risk for developing atherosclerosis. Risk factors for atherosclerosis have also been shown to be linked to the presence of the disease at a given time, a fact that may be helpful when screening for additional atherosclerotic disease in the known arteriopath. Risk factors .were recorded in 471 patients admi"ed to hospital with symptoms of atherosclerosis. In patients admi"ed primarily with peripheral vascular disease, risk factors linked to the presence of additional coronary artery disease were a family history of ischaemic heart disease (odds ratio = 2,6), the presence of carotid artery disease (odds ratio = 1,9) and high fasting serum triglyceride levels (P < 0,04). Grouping these factors together usin.g logistic regression, ischaemic heart disease could be predicted with a sensitivity of 72% and a specificity of 43%. Patients admitted with carotid artery disease were more likely to have ischaemic heart disease in the presence of peripheral vascular disease (odds ratio = 1,9) and a raised serum cholesterol level (P < 0,02), while female gender (odds ratio = 2,9) and an increase in age (P< 0,001) were linked to an increased prevalence of concomitant atherosclerosis in patients admmed with acute myocardial infarction or for elective coronary artery bypass surgery. Using an age cut-off point, additional atherosclerosis could be predicted with a sensitivity of 32% and a specificity of 88% in these patients

The Holistic Life-Crafting Model: a systematic literature review of meaning-making behaviors

Pursuing meaningful life experiences is vital for wellbeing and health. Crafting strategies, such as job crafting and work-life balance crafting, have been developed to create meaning in specific life domains. However, these strategies share common underlying behaviors that transcend specific contexts. Building on this understanding, we propose a comprehensive “holistic life-crafting” approach that integrates overlapping behaviors from various crafting strategies. This study aims to clarify the theoretical conceptualization of life-crafting by identifying common strategies and behaviors underlying different meaning-making crafting approaches. Through a systematic literature search of six databases between January and April 2022, we identified 16,479 published records. Using predefined inclusion–exclusion criteria, 51 records (reflecting five crafting approaches, resulting in 223 different crafting behaviors) remained. Through content analysis, we grouped these behaviors into seven broader crafting strategies, forming the “holistic life-crafting” approach. Findings suggest that life-crafting is a holistic, continuous process of proactive meaning-making by intentionally balancing life demands with available resources and altering life’s cognitive, environmental, interest, relational, skill, and task-related aspects to promote personal growth and wellbeing. The holistic approach encompasses cognitive, environmental, interest, relational, resources-demands, skill, and task crafting strategies. This framework provides a comprehensive understanding of how individuals can actively shape their lives to promote more meaningful life experiences across different domains.Systematic review registrationPROSPERO, identifier CRD42022333930

Help-seeking by substance dependants presenting to healthcare professionals in the Free State Province

Introduction. Current data regarding treatment needs in South Africa for substance dependence are based on admissions to specialised treatment centres. The data therefore do not include patients presenting to independent healthcare workers and state hospitals. Aim. The aim of this study was to investigate help-seeking behaviour for substance dependence disorders from the perspective of healthcare professionals at various levels of the referral chain in Free State Province. Design. A descriptive study was performed. Setting. Treatment environments in Free State Province accessible to substance-dependent persons. Participants. General practitioners, private psychiatrists, prescribing healthcare professionals at state hospitals and treatment centres, and non-prescribing therapists responsible for management of substance-dependent persons. Measurements. A questionnaire was used to determine the level of help-seeking experienced by the participants regarding various classes of psycho-active substances. Findings. The presentation of alcohol, cannabis, opioid, benzodiazepine, ecstasy, cocaine and inhalant dependency at general practitioners, private psychiatrists, treatment centres and non-prescribing therapists was compared. Different patterns of help-seeking for substance dependence from the various professional groups were detected. Regarding alcohol dependence, 40.3% of private general medical practitioners reported being confronted with alcohol dependence at least once per month, compared with 100% of treatment centre representatives and private psychiatrists, 70.6% of state hospitals and 53.8% of non-prescribers. State hospitals reported the highest frequency for contact with cases of cannabis dependence, compared with the other professional groups, while psychiatrists reported the highest contact with cases involving benzodiazepine, cocaine and ecstasy. Therapists reported a higher level of contact with inhalant dependence, while this group virtually never presented at general practitioners and private psychiatrists. Conclusion. Help-seeking data can be used in conjunction with other data, such as treatment demand data, to inform and adapt policies and practice. Variations in the manifestation of help-seeking behaviour at various groups may be important pointers to conditions that influence help-seeking, and therefore should be investigated further

Analytical treatment of interacting Fermi gas in arbitrary dimensional harmonic trap

We study normal state properties of an interacting Fermi gas in an isotropic harmonic trap of arbitrary dimensions. We exactly calculate the first-order perturbation terms in the ground state energy and chemical potential, and obtain simple analytic expressions of the total energy and chemical potential. At zero temperature, we find that Thomas-Fermi approximation agrees well with exact results for any dimension even though system is dilute and small, i.e. when the Thomas-Fermi approximation is generally expected to fail. In the high temperature (classical) region, we find interaction energy decreases in proportion to T^(-d/2), where T is temperature and d is dimension of the system. Effect of interaction in the ground state in two and three-dimensional systems is also discussed.Comment: 15 pages, 4 figure