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An investigation on humpback whales' distribution in relation to Antarctic sea ice in the IDCR/SOWER dataset
Get PDFExisting literature has identified humpback whales (Megaptera novaeangliae) as climate sentinels since their feeding ecology is inextricably linked to the oceanic features around Antarctica, and to the seasonal sea ice. The changing Antarctic cryosphere in response to climate change threatens not only their habitat but also their prey resources. Understanding the interaction between the changing Antarctic Sea ice and its influence on the recovering humpback whales' distribution and behaviour is fundamental. Long-term ecological research offers the potential to understand ecological interactions and variability therein, over time scales relevant to both the life history of the animals and their physical environment. Implemented to assess the effectiveness of the moratorium on baleen whale densities, the IDCR/SOWER dataset is the sole cetacean long-term dataset containing in-depth information about the recent status of all Southern Ocean baleen whales. This study examines the potential utility of this dataset beyond its original scope, specifically assessing how it can contribute to climate research. Using the humpback whale sightings dataset, I prepared a workflow analysis to visually assess the distribution of humpback whales during the IDCR/SOWER surveys in relation to the sea ice from climate data records. The analysis was framed around the use of regional sectors typically used for sea ice research, rather than the feeding areas identified by the International Whaling Commission. The results show that although humpback whales indicate southward expansion as the sea ice retreats, the influence of interannual changes in sea ice on sightings is not uniform, and evident only in a few sectors. Taking into consideration the caveats of using presence/absence whale distribution data, this study represents a significant step forward in demonstrating the potential of this dataset for interdisciplinary research on polar environments beyond its original intentio
Early summer rainfall variability in the Congo Air Boundary Region
Get PDFStrong meridional rainfall gradients exist between the tropics and subtropics in southwestern Africa, bounded to the north by the moist Congo basin and the south by the Kalahari Desert. This region termed the tropical-subtropical divide (TSD) here, has recently faced one of the worst droughts in the last 40 years, contributing to local food insecurity. Compared to the rest of southern Africa, relatively little scientific attention has focused on the domain, partly due to long-term conflict preventing reliable observations. In this study, focus is placed on understanding rainfall characteristics and variability during the austral summer (October – April) across southwestern Africa using daily fifth generation of European Centre for Medium-Range Weather Forecast Reanalysis (ERA5) and Climate Hazard Group InfraRed Precipitation with stations (CHIRPS) data. Evaluation of gridded rainfall products in the region found that CHIRPS and ERA5 compare well with limited station data in the region. Using the ERA5 data, results reveal a significant decreasing trend of early summer (October-December) rainfall totals as well as rainy days since 1979 to present. The importance of the early summer rainfall is that it accounts for up to 60% of the total summer rainfall. There also appears a statistically significant long-term decreasing trend in rainfall onset (i.e., later onset), which typically occurs during the late October – early November months. A late onset could lead to dry early summers, a decrease in rainy season length, and severe droughts in the region in future. However, the late summer (January – April) increasing trend in rainfall totals might offset any large changes in summer rainfall. Correlation analysis reveals that although there is a significant relationship between early summer rainfall and rainy days and some of the main modes of climate variability and regional circulation systems, although it was highly variable across the domain. Thus, two sub-domains termed western and eastern region (“WR” and “ER”) were also investigated. A significant relationship between sea-surface temperature from the Niño 3.4 region and Indian Ocean Dipole (IOD) with rainfall and rainy days was only limited to the extreme southeast of Zambia. For late summer, when El Niño-Southern Oscillation (ENSO) has matured, there is a strong contrasting signal of significant positive (negative) relationship with rainfall totals and rainy days in the Angola Highlands (the rest of subtropical southern Africa). Angola Low index significantly and positively (negatively) correlates with early summer rainfall in the western (eastern) parts of the domain. The relationship between the Botswana High with early summer rainfall and rainy days is only limited to the eastern parts of the region. Lastly, a composite analysis of wet and dry years for the whole tropical-subtropical divide region as well as two sub-domains (western and eastern region) were investigated. Given the considerable variability within the region, anomalously dry and wet years are not consistent for the tropical-subtropical divide region, western and eastern region. Composites of wet years for the tropical-subtropical divide region and both sub-domains shows that the western Indian Ocean appears to act as the main source of moisture for the region. Typically, wet composites over the eastern region (western region) are characterized by stronger (weaker) Angola Low, while Botswana High influence over wet and dry years is only limited to the eastern region
An agent-based model of the emergency medical services system in Nelson Mandela Bay municipality
Get PDFInefficient EMS systems can lead to delays in accessing urgent medical care and increased mortality for critically ill or injured patients. In the Nelson Mandela Bay district of South Africa's Eastern Cape province, the public EMS system struggles to meet its own response time targets. In addition to long response times, staff and vehicles are not always allocated efficiently, as highly-skilled personnel and specialised vehicles are frequently used for responding to low priority or planned patient transport calls. This decreases the quality of medical care provided to the most critically ill patients. The aim of this research is to improve patient outcomes in Nelson Mandela Bay's under resourced public EMS system, which serves the majority of the local population, including those who are unable to afford private EMS. It therefore has the potential to improve access to EMS for the most underprivileged communities, and enhance healthcare equity in the re gion. To achieve this, the research provides decision-makers in the Eastern Cape Department of Health (ECDoH) with a set of evidence-based recommendations for reducing response times, and improving the efficiency of staff and vehicle allocations. These recommendations are sen sitive to the resource-limited nature of the setting, and prioritises interventions that do not require additional staff or vehicles. The EMS system was modelled using an agent-based simulation model, which enables multiple sources of variation in the system to be explicitly accounted for, and nuanced scenarios to be investigated. The model was built and validated using anonymised EMS call data, a smaller dataset of precise response times, and travel time estimates from Google Maps. A key finding of this research is that the median response time of Priority 1 calls can be reduced to below the 30 minute target by implementing changes to dispatching, rerouting and prioritisation behaviour alone, and without increasing resources. These improvements come at the expense of substantial increases in median response times for lower priority calls, but these increases can be counteracted by moderately scaling up the number of staff employed. Improving the accuracy of dispatchers in triaging calls was identified as a particularly effective method of reducing response times, without considerable increases to response times for other call types. A number of policy recommendations were formulated based on these results. These will be presented to management in the Eastern Cape Department of Health, aiming to guide policy interventions for Nelson Mandela Bay's EMS system
Molecular phylogenetics, systematics, reproductive safeguarding and chromosome evolution of the genus Lachenalia (Asparagaceae: Scilloideae)
Get PDFThe genus Lachenalia, comprising 142 species and belonging to the monocotyledonous family Asparagaceae, is morphologically diverse and the most species-rich member of the family in southern Africa. Past attempts to infer a well-resolved and robustly supported phylogenetic tree using Sanger sequencing of candidate loci and/or morphological characters have been largely unsuccessful. A new phylogenetic hypothesis for Lachenalia is presented, using multi-locus sequence data sampled from living material of 132 taxa via maximum likelihood and coalescent-based species tree estimation (ASTRAL), as applied to 378 hybrid enrichment loci. This resolves species-level relationships with good support, thereby providing a sound basis for a new infrageneric classification, revealing several new taxa which are described here, and, most importantly, establishing a solid framework for downstream evolutionary studies. A dated version of the multi-locus phylogenetic tree is employed here to test the hypothesis that pollen limitation, resulting from a low abundance of insect pollinators, promotes the evolution of reproductive safeguarding traits (self compatibility, autonomous selfing, bird pollination and clonal propagation) in low insect abundance contexts (i.e., infertile fynbos heathland, and species which flower outside of the austral spring season). Ancestral state reconstructions identify an association with non-fynbos vegetation and spring-flowering as ancestral, with the transition to fynbos and non-spring flowering having taken place multiple times. Ordinary and phylogenetic regressions suggest that bird pollination and self-compatibility are selected for in fynbos and in non-spring flowering lineages, with autofertility being positively associated with non-spring flowering. These patterns support interpretation of these traits as reproductive safeguarding adaptations under reduced insect pollinator abundance. The dated multilocus phylogenetic tree is also used to explore the evolution of cytotype and genome size in Lachenalia. Novel genome size data for 124 species are reported and reconciled with existing karyotype data to show that genome size variation is largely a product of polyploidization, with polyploidy yielding lineages that are mostly short-lived and recent. By contrast, dysploid change, which is frequent in Lachenalia but has little impact on genome size, yields lineages that persist through time and diversify. Lachenalia describes a dysploid reduction series with a high ancestral base number
The relevance of non-legal technical and scientific concepts in the interpretation and application of the law of the sea
Get PDFOf necessity LOSC Articles are brief and in some instances vague and requiring interpretation. There is general consensus that LOSC is successful and that its vagueness in certain areas is an asset allowing a variety of otherwise contrary attitudes to be accommodated. It is necessary to analyse the Articles with a view to a better understanding of them and to possibly prepare for some future conference or convention that will more than likely be necessary to resolve some of the remaining problems. To illustrate the need for greater understanding of some of the Articles of LOSC the United Nations Office for Ocean Affairs and Law of the Sea found it necessary to convene a conference of 'experts' during 1993 and 1995 to consider the implications of the complex Articles of LOSC which deal with claims to the continental shelf. Criteria contained in Article 76 allowing for maximum outer limits of the continental shelf and other criteria to justify a claim are complicated and require experience in many fields including marine geology, geography, surveying, and geodesy. The intention is therefore to analyse the possible interpretation, application and consequences of the implementation of Articles in LOSC, and more particularly in a Southern African context. Provisions of LOSC, where technical and scientific considerations are crucial, will be selected for consideration. These include those involving geodetic, geographical, geological, survey, navigational, organisational, and social and resource factors. The effect of these factors on LOSC will be assessed and interpreted and any shortcomings found in the Articles will be highlighted and suggestions made for their possible improvement or interpretation
Generating new data points using singular value decomposition
Get PDFThis study presents an innovative solution to the challenge of generating new data points for small data sets. It introduces a Single Value Decomposition (SVD)-based model that draws inspiration from the ability of SVD to estimate a lower rank matrix. This approach seeks to overcome the limitations imposed by sample size constraints by expanding available data. Motivated by challenges faced during algorithm development due to small data sets, the study proposes the SVD-based model, evaluates its efficacy in replicating original data attributes and compares model performance with new and original data. The method involves utilising SVD to generate new data, mimicking a predictive modelling formula by combining systematic and error components. The generated data set retains the distribution of the original data but introduces distinct error values, facilitating efficient data generation. Through graphical and quantitative assessments, including histograms, box plots, correlation analysis and reconstruction error evaluations, the effectiveness of the method is demonstrated. The study focuses on comparing SVD-generated data sets with original data across three data sets: Abalone, Life Expectancy and NBA. Findings indicate close approximation of distribution, correlation and model performance attributes between SVD-generated and original data sets. Improved similarity with increasing observation count enhances comparability and model performance of SVD-generated data. While minor deviations are noted in specific scenarios, the study underscores potential of SVD in generating new data points from the original data sets, making it a valuable tool for data augmentation and analysis across diverse data sets
South African university students' user experience of mobile applications for anxiety and depression
Get PDFBackground: Globally, university students have been shown to be disproportionately affected by common mental disorders (CMDs). The primary CMDs reported by students have been anxiety and depression. Research on South African students has proven no exception. Moreover, this predicament is worsened by low rates of help-seeking, historically entrenched systemic inequality regarding access to resources, a lack of culturally appropriate interventions, and a population that tends to be overly self-reliant. Objective: With the prevalence of CMDs in mind, as well as the many challenges students face, it was deemed worth exploring current, available alternatives. Given some evidence for the use of mobile mental health (MMH) applications (apps) among university students in high income countries, the current study aimed to investigate South African university students' user experience of MMH apps for depression and anxiety. Methods: South African students in the psychology department of the University of Cape Town were recruited to make use of two MMH apps, Headspace and Woebot, for two weeks total, but one week per app. They then completed online questionnaires related to their experience of using these apps, and semi-structured interviews were conducted, recorded, and transcribed by the researcher. Due to a lack of meaningful data from the online questionnaires, only the semi-structured interviews were used for analysis. Braun and Clarke's (2006) method of thematic analysis was used to analyse the data. Results: After analysing the semi-structured individual interviews, themes were defined, described, and discussed. The participants expressed that the apps facilitated insight and self-awareness, and were found to be supportive, encouraging, and convenient. However, they valued different aspects of the two apps, with each offering something that the other did not. The importance of each design was also highlighted as a vital factor in the overall user experience, while affordability was also emphasised for the student population in particular. Conclusion: The two apps were found to be accessible and acceptable for participants in this South African university setting. Additionally, user experience design enhanced their experiences. However, as each app offered different approaches and benefits, the integration of features could be something to work towards. There are also important ethical considerations that need to be factored before recommending them. Further research and development are required in order to address these concerns
Section 35(5): are the superior courts consistent in their application of the factors to be taken into account in excluding unconstitutionally obtained evidence where admission would be detrimental to the administration of justice?
Get PDFSections 35(5) of the Constitution requires the court to determine whether the admission of unconstitutionally obtained evidence will render the trial unfair or otherwise be detrimental to the administration of justice. The main focus of this thesis is the second leg, namely whether the inclusion of unconstitutionally obtained evidence would be detrimental to the administration of justice. Jurisprudence arising out of art 24 of the Canadian Charter has had a significant influence on the interpretation of s 35(5) in determining whether the administration of justice is being undermined due to the admission of evidence. Presence of good faith, the nature of the transgression, determining whether there was an opportunity for evidence to be obtained legally, whether the evidence is real evidence and whether the evidence would have been inevitably obtained are crucial factors that the courts consider. Section 35(5) facilitates the balancing in criminal trials of the accused's, as well as the public's interests. The purpose of this study is to examine the coherence of Superior Courts judgments in dealing with the exclusion of unconstitutionally obtained evidence through the lens of the second leg. The history of judicial authority surrounding this topic will be discussed, ranging from earlier precedent serving as the backbone of the application of the exclusionary rule – while an in depth discussion of recent Superior Court cases ranging from the years of 2019 to 2023 will be the used to determine the more recent application of s 35(5) and whether the judiciary has consistently applied the aforesaid factors
Development of a GC-MS method to determine toxic alcohols and their metabolites in postmortem blood
Get PDFThe intentional and accidental ingestion of toxic alcohols represents a health care and potential public health concern within South Africa. Household and industrial antifreezes and brake fluids contain ethylene glycol (ETG) and diethylene glycol (DEG), which cause toxicity within humans. Other toxic alcohols such as 1,4-butanediol (1,4-BD) and propylene glycol (PGL) also show toxicity within the human body. Some of these analytes have previously been implicated in cases of fatal poisoning. However, the extent to which toxic alcohols contribute to death in South Africa is yet to be determined, as these are not routinely investigated in forensic toxicological analysis of biological samples. The purpose of this study was to modify and characterise a gas chromatography-mass spectroscopy (GC-MS) method for the quantitative determination of ETG, DEG, 1,4-BD, PGL, and the toxic metabolite of ETG, glycolic acid (GCA), in postmortem whole blood samples at the Forensic Toxicology Unit (FTU) in the Western Cape, South Africa. We describe the alteration of an existing method that examines most of these target analytes among others by Meyer, Weber and Maurer (2011), utilising a lower quantity of N,O-bis-(trimethylsilyl) trifluoroacetamide (BSTFA) and post-mortem whole blood rather than plasma. The method was characterised according to parameters of calibration model, limit of detection, limit of quantification, bias, precision, processed sample stability, and carryover. Linearity was observed for all analytes between 25– 100 µg/mL with preliminary limits of detection at 25 µg/mL. Preliminary limits of quantification were 25 µg/mL for 1,4-BD, and 50 µg/mL for ETG, PGL, GCA and DEG. Recovery was calculated at ~40% for all analytes, and processed sample stability was calculated to be acceptable for up to 72 hours. The developed method was applied to several post-mortem cases of toxic alcohol ingestion at the Observatory Forensic Pathology Institute (OFPI). In conclusion, the method for the determination of toxic alcohols in post-mortem samples was successfully developed and characterised for a government forensic toxicology laboratory in the Western Cape. Future work will include the validation of this method to streamline analytical determination of the morbidity and mortality related to toxic glycols in the Western Cap
Clinico-epidemiological profile of cardiac admissions at a district level hospital in South Africa: a cohort study
Get PDFBackground Nineteen percent of all deaths during 2016 in South Africa (SA), were due to cardiovascular disease. Despite this notable burden, research describing cardiac admissions at the district level is limited and thus, area-specific studies are warranted to provide a perspective on SA's unique population of rich genetic, geographic, social, and cultural diversity. The aim of this study was to describe the epidemiological and clinical characteristics, associated risk factors and outcomes of cardiac patients admitted to a district level hospital in SA, in order to fill the void within currently available literature. Methods We conducted a retrospective records review of all patients admitted to Victoria Hospital Wynberg with a primary cardiac diagnosis, between 1 September 2020 to 30 November 2020. Data were transcribed onto a bespoke data collection form and captured into the Victoria Internal Medicine Research Initiative (VIMRI) electronic registry. The study was approved by UCT HREC (048/2022), the Western Cape Government and Victoria Hospital Board. Results Our cohort consisted of 218 patients (52.8% male) with a mean age (SD) of 60 years (±14.6), and an age range from 22 to 95 years. Acute decompensated heart failure, together with acute coronary syndrome, were responsible for 87.4% of all admissions. The mean length (SD) of stay was 4 days (±3.5 days). Most prevalent risk factors among admitted patients included hypertension (76%), cigarette smoking (55%) and diabetes (42.7%). Amongst diabetics, 27.3% were considered to have acceptable diabetic control (HbA1c £7%). Most frequently reported precipitants for hospital admission were prior inadequate therapy, discontinuing chronic medication, uncontrolled hypertension, disease progression, and ongoing substance use. Twenty-one percent of the cohort were transferred to cardiology for further management and specialist intervention. The inpatient mortality rate was 9.2%, and one-year mortality rate was 18.8%. Readmission within six months was reported amongst 30.8% of our cohort. Discussion and Conclusion Our study provides important insight into the clinico-epidemiological profile of cardiac admissions at a public district level hospital in SA. We report notable rates of morbidity, readmission, and mortality together with a high prevalence of well-known cardiovascular risk factors of hypertension, diabetes mellitus and cigarette smoking. While the in-hospital and one-year mortality rates are notable, but not too unexpected when compared to available data, we nevertheless recommend programmes focused on improving adherence to treatment and optimization of heart failure therapy at a primary care level, as means to reduce rates of poor adherence, suboptimal anti-failure therapy and poor glycaemic control observed in our cohort