Quantifying the contribution of riparian total evaporation to streamflow transmission losses: preliminary investigations along the groot letaba river

The Groot Letaba River, situated in the semi-arid north-eastern region of South Africa is an example of a river system in which the uncertainty associated with transmission losses (TL) has limited the effective management of environmental water requirement (EWR) flows. TL along the river significantly impacts EWR flows, as it is often the case that specified EWR releases are not adequately received further downstream

The use of Radon (Rn222) isotopes to detect groundwater discharge in streams draining Table Mountain Group (TMG) aquifers

Environmental isotopes have been used for decades as natural tracers in studies aimed at understanding complex hydrogeological processes such as groundwater and surface water interactions. Radon (Rn222) is a naturally occurring, radioactive isotope which is produced from radium (Ra226) during the radioactive decay series of uranium (U238). Since U238 is present in most geological substrates, Rn222 is produced in various lithological structures and subsequently transported with groundwater through fractures and pore spaces in an aquifer towards surface water discharge points in rivers and springs. This study aimed to determine (i) the concentration of Rn222 within both surface water and groundwater in Table Mountain Group (TMG) aquifer systems, and (ii) the feasibility of using Rn222 isotopes as a natural tracer in groundwatersurface water interaction studies. This study was conducted in a highly fractured TMG aquifer system near Rawsonville, South Africa. Surface water from two perennial rivers (i.e. Gevonden and Molenaars), together with groundwater from a nearby borehole, were sampled and their corresponding Rn222 concentrations measured. Our study found median Rn222 concentrations in the Gevonden River of 76.4 Bq∙L-1 and 67.2 Bq∙L-1 in the dry and wet seasons, respectively. Nearly 12% of surface water samples exceeded 100 Bq∙L-1

Faith seeking understanding

The debate between faith and science is an ongoing and dynamic conversation marked by the need to consistently factor in new data generated by the sciences, and new perspectives developed in theology. In this book, a group of theologians and ethicists provide insights into the debate from a faith perspective. The basic thesis permeating the discussions is that faith and science are capable of enriching and complementing each other, albeit in their own unique way. What unifies faith and science is the search for truth. What differentiates them is the unique lenses they employ to find the truth. In the end, both scientists and theologians must take into account all the pathways and lenses that lead us to a better understanding of reality. This study presents concrete examples of how theological knowledge and scientific data can be fruitfully used and integrated to develop new horizons of understanding. The general aim of this contribution was to narrow in on some of the burning themes that are driving the faith or science scholarly debate. Each contributor highlights a different aspect of the debate. The topics addressed include theoretical perspectives on the science-faith relation, the ancient scientific worldview of the creation narratives in Genesis, evolution and human origins, science and African Pentecostalism, faith and the Fourth Industrial Revolution, science and transhumanism, science and traditional medicine, and the role that faith and science can play in the human quest for meaning. Most of the contributors approach the topic from a post-foundationalist and postpositivist epistemological point of view. A wide range of hermeneutical methods is employed, ranging from systematic biblical-theological perspectives to literary and source criticism. Analytical, normative and existential philosophical arguments are also utilised throughout the course of the book. The most important contribution of the book lies in the transdisciplinary perspectives that emanate from the discussion. The ways in which the authors go about integrating theological and scientific perspectives to address ultimate questions about meaning and to inform moral discourse show that religion still has an important role to play in a world increasingly shaped by technological rationality. At the same time, it indicates that religion and science do not have to stand in conflict with each other. If the two lenses on reality engage in mature dialogue, they can enrich, inform and, on some occasions, even correct each other. The target audience of this book includes theological scholars, natural scientists and science philosophers. This book contains no plagiarism, and none of the work has been published elsewhere

Faith seeking understanding

The debate between faith and science is an ongoing and dynamic conversation marked by the need to consistently factor in new data generated by the sciences, and new perspectives developed in theology. In this book, a group of theologians and ethicists provide insights into the debate from a faith perspective. The basic thesis permeating the discussions is that faith and science are capable of enriching and complementing each other, albeit in their own unique way. What unifies faith and science is the search for truth. What differentiates them is the unique lenses they employ to find the truth. In the end, both scientists and theologians must take into account all the pathways and lenses that lead us to a better understanding of reality. This study presents concrete examples of how theological knowledge and scientific data can be fruitfully used and integrated to develop new horizons of understanding. The general aim of this contribution was to narrow in on some of the burning themes that are driving the faith or science scholarly debate. Each contributor highlights a different aspect of the debate. The topics addressed include theoretical perspectives on the science-faith relation, the ancient scientific worldview of the creation narratives in Genesis, evolution and human origins, science and African Pentecostalism, faith and the Fourth Industrial Revolution, science and transhumanism, science and traditional medicine, and the role that faith and science can play in the human quest for meaning. Most of the contributors approach the topic from a post-foundationalist and postpositivist epistemological point of view. A wide range of hermeneutical methods is employed, ranging from systematic biblical-theological perspectives to literary and source criticism. Analytical, normative and existential philosophical arguments are also utilised throughout the course of the book. The most important contribution of the book lies in the transdisciplinary perspectives that emanate from the discussion. The ways in which the authors go about integrating theological and scientific perspectives to address ultimate questions about meaning and to inform moral discourse show that religion still has an important role to play in a world increasingly shaped by technological rationality. At the same time, it indicates that religion and science do not have to stand in conflict with each other. If the two lenses on reality engage in mature dialogue, they can enrich, inform and, on some occasions, even correct each other. The target audience of this book includes theological scholars, natural scientists and science philosophers. This book contains no plagiarism, and none of the work has been published elsewhere

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

Christian ethics and political economy

The value-free and relativistic human and scientific discourses have led to an era of ideology. From fascism at the dawn of the century, through liberalism and the associated phenomenon of unfettered statism, to the current disillusionment of postmodernism and relativism with endeavours towards new mercantilism. All have maintained poverty, inequality and created scepticism amongst both lay persons and academics. Above all else a renewed yearning for moral and ethical direction in political and economic conduct has been created. This book provides a Christian ethical reflection on political-economic conduct in South Africa as an alternative to current modernistic ideas. This book aims to produce new Christian ethical insight into the value of new liberal perspectives on the enhancement of the South African political economy. New Christian ethical insight will be gained through new perspectives on the South African political economy

Electronic properties of shallow level defects in ZnO grown by pulsed laser deposition

We have used deep level transient spectroscopy (DLTS) to characterise four defects with shallow levels in ZnO grown by pulsed laser deposition (PLD). These defects all have DLTS peaks below 100 K. From DLTS measurements and Arrhenius plots we have calculated the energy levels of these defects as 31 meV, 64 meV, 100 meV and 140 meV, respectively, below the conduction band. The 100 meV defect displayed metastable behaviour: Annealing under reverse bias at temperatures of above 130 K introduced it while annealing under zero bias above 110 K removed it. The 64 meV and 140 meV defects exhibited a strong electric field assisted emission, indicating that they may be donors

Electronic properties of shallow level defects in ZnO grown by pulsed laser deposition

We have used deep level transient spectroscopy (DLTS) to characterise four defects with shallow levels in ZnO grown by pulsed laser deposition (PLD). These defects all have DLTS peaks below 100 K. From DLTS measurements and Arrhenius plots we have calculated the energy levels of these defects as 31 meV, 64 meV, 100 meV and 140 meV, respectively, below the conduction band. The 100 meV defect displayed metastable behaviour: Annealing under reverse bias at temperatures of above 130 K introduced it while annealing under zero bias above 110 K removed it. The 64 meV and 140 meV defects exhibited a strong electric field assisted emission, indicating that they may be donors

Christian hermeneutics in South Africa

Hermeneutics remains a divisive and polarizing topic within scholarly and ecclesiastical communities in South Africa. These tensions are not limited to theoretical differences but often crystallize on a grassroots level when local churches and church assemblies have to make important decisions on controversial ethical topics such as ordaining women in church offices, assessing the ethics of gay marriages, and taking a stance on the land debate in South Africa. This book makes a unique contribution in two ways: firstly, it focuses on the uniquely South African hermeneutical landscape; secondly, it relates theories to practical ethical application. The unique scholarly contribution of this consists in it relating hermeneutics to ethics within the South African landscape. A diverse group of scholars have been invited to partake in the project and the views expressed are often quite diverse. This allows readers to develop an understanding and sensitivity of the various angles employed and the interests at stake in addressing difficult societal problems

Quantifying the contribution of riparian total evaporation to streamflow transmission losses: Preliminary investigations along the Groot Letaba river

The Groot Letaba River, situated in the semi-arid north-eastern region of South Africa is an example of a river system in which the uncertainty associated with transmission losses (TL) has limited the effective management of environmental water requirement (EWR) flows. TL along the river significantly impacts EWR flows, as it is often the case that specified EWR releases are not adequately received further downstream. Due to the limited understanding of the magnitude of TL, as well as the dominant contributing processes to TL within the region, it remains a challenge to operate the river using downstream targets far from the source of operations. In an attempt to address this knowledge gap, detailed characterizations of hydrological processes were performed along the lower reaches of the river, which centred around the estimation of riparian total evaporation and quantifying the rapport between surface and subsurface water flow processes. Riparian total evaporation was estimated using the satellite-based surface energy balance system model, soil water evaporation measurements and open water evaporation estimates. Losses from the river to the adjacent aquifer were determined from the continuous monitoring of the groundwater phreatic surface and characterization of aquifer hydraulic properties. The results of these investigations indicated that present flows within the system are likely to be insufficient to satisfy gazetted median and extreme low flow targets. Overall, the study details key hydrological processes influencing TL along the river. It should, however, be noted that these observations only provide an understanding of the system over a limited observation period