The detection of wetlands using remote sensing in Qoqodala, Eastern Cape

Bibliography: leaves 66-68.This dissertation aims to establish the possibilities of mapping wetlands in Qoqodala, Eastern Cape Province, South Africa, using Landsat and/or Aster imagery. The methodology for mapping wetlands using Landsat imagery, proposed by Thompson, Marneweck, Bell, Kotze, Muller, Cox and Smith (2002) is adapted and applied to the study area. The same methodology is modified for use with Aster imagery and applied to the study area. In addition, the possibilities of treating Aster as a hyperspectral image are investigated, and a methodology using hyperspectral processing techniques is implemented

Diabetes mellitus complicating pregnancy: a study of maternal vascular endothelial dysfunction and of placental terminal villous ultrastructure

Insulin dependant diabetes is metabolic disorder associated with vascular endothelial dysfunction. Pregnancy, in a woman with diabetes, is associated with an increased risk of maternal vascular complications, such as pre-eclampsia and progression of microvascular disease. These vascular complications are in part mediated though inflammatory effects on the vessel wall. Insulin dependent diabetes is also associated with an increased risk of fetal complications including intrauterine hypoxia and stillbirth. Maternal vascular dysfunction may alter the feto-placental environment and be associated with aberrant placental vascular development. We therefore aimed to determine: (1) if pregnancy in the insulin dependent (type I) diabetic woman is associated with increased maternal endothelial dysfunction, and (2) if the ultrastructure of the terminal placental villus, the functional exchange unit, is altered in these pregnancies.As an index of maternal vascular function circulating concentrations of defined endothelial-derived cell adhesion molecules were assessed. An ELISA was used to quantify the concentrations of these cell adhesion molecules, throughout diabetic and control pregnancies and in matched non-pregnant women. The circulating concentrations of the cell adhesion molecules: E-selectin and ICAM-1 were increased in non-pregnant diabetic subjects compared to non-pregnant controls. These cell adhesion molecules interact with neutrophils and provide evidence of endothelial dysfunction in our population of non-pregnant diabetic women. In contrast, during pregnancy there was no difference in the circulating concentrations of E-selectin or ICAM-1 between diabetic and control groups. The concentration of E-selectin was significantly reduced when measured in the pregnant compared to the non-pregnant diabetic cohorts. Circulating concentrations of von Willebrand factor, an established index of endothelial dysfunction, were also comparable in diabetic and control pregnant cohorts. These findings suggest that pregnancy, in our population of diabetic women, may actually be a time of vascular well-being. We hypothesize that this is a reflection of the improved glycaemic control achieved by these women during pregnancy

The application of the surface energy balance system model to estimate evapotranspiration in South Africa

Includes abstract.Includes bibliographical references.In a water scarce country like South Africa with a number of large consumers of water, it is important to estimate evapotranspiration (ET) with a high degree of accuracy. This is especially important in the semi-arid regions where there is an increasing demand for water and a scarce supply thereof. ET varies regionally and seasonally, so knowledge about ET is fundamental to save and secure water for different uses, and to guarantee that water is distributed to water consumers in a sustainable manner. Models to estimate ET have been developed using a combination of meteorological and remote sensing data inputs. In this study, the pre-packaged Surface Energy Balance System (SEBS) model was used for the first time in the South African environment alongside MODerate Resolution Imaging Spectroradiometer (MODIS) satellite data and validated with eddy covariance data measured in a large apple orchard (11 ha), in the Piketberg area of the Western Cape. Due to the relative infancy of research in this field in South Africa, SEBS is an attractive model choice as it is available as open-source freeware. The model was found to underestimate the sensible heat flux through setting it at the wet limit. Daily ET measured by the eddy covariance system represented 55 to 96% of the SEBS estimate, an overestimation of daily ET. The consistent underestimation of the sensible heat flux was ascribed to sensitivities to the land surface air temperature gradient, the choice of fractional vegetation cover formula as well as the height of the vegetation canopy (3.2 m) relative to weather station reference height (2 m). The methodology was adapted based on the above findings and was applied to a second study area (quaternary catchment P10A, near Grahamstown, Eastern Cape) where two different approaches for deriving surface roughness are applied. It was again demonstrated that the sensible heat flux is sensitive to surface roughness in combination with land surface air temperature gradient and again, the overestimation of daily ET persisted (actual ET being greater than reference ET). It was concluded that in complex environments, at coarse resolution, it is not possible to adequately describe the remote sensing derived input parameters at the correct level of accuracy and at the spatial resolution required for the accurate estimation of the sensible heat flux

Promoting and implementing self care: a mixed methods study of offshore workers and remote healthcare practitioners.

The oil and gas industry is a vital contributor to the global economy and a key source of employment within oil-producing countries. Oil production is largely dependent on a skilled population who are adept in coping with the demands of an offshore environment. Due to the high risk nature of work offshore, it is a requisite that personnel engage in health promoting behaviours. The research aimed to identify aspects of offshore workers self care which required behaviour change and the behavioural determinants which were associated with engagement in self care. A mixed methods design was utilised to generate novel data and original findings. Phase 1 used a quantitative cross-sectional online survey to assess offshore workers (n=352, 53.6% response rate) health, quality of life, mental wellbeing and self care status. The findings highlighted key areas of concern, as indicated by negative scoring across measures, relating to: overweight/obesity; medication adherence; absenteeism (with regard to travelling offshore); medical evacuation; lack of adherence to 5-a-day fruit and vegetable guidelines; physical activity; smoking; hazardous alcohol use, and insomnia. Phase 2 used qualitative theory-based telephone interviews to explore self care behaviours from the perspective of offshore workers (n=16). Offshore workers who had completed a survey and indicated they would like to receive further information on the interviews were invited to participate. Both the interview schedule and data analysis were informed by the Theoretical Domains Framework (TDF). Healthy eating and physical activity were the behaviours most frequently discussed by offshore workers and identified as areas requiring behaviour change. TDF domains representing both behaviours included: beliefs about capabilities; beliefs about consequences; intentions; goals; memory, attention and decision processes; environmental context and resources; social influences; emotion, and behavioural regulation. Phase 3 used qualitative theory-based telephone interviews to explore offshore workers (n=13) self care behaviours from the perspective of remote healthcare practitioners. Both the interview schedule and data analysis were informed by TDF. Healthy eating and harmful/hazardous alcohol use were the behaviours most frequently discussed by remote healthcare practitioners and identified as areas requiring behaviour change. TDF domains representing both behaviours included: knowledge; environmental context and resources; social influences; emotion, and behavioural regulation. The findings, when triangulated suggest that offshore workers may benefit from the implementation of a self care intervention which targets healthy eating, physical activity and alcohol consumption. It is advised that the intervention target multiple self care behaviours and that development is underpinned by behaviour change theory to ensure effectiveness. The intervention may be tailored in accordance with the TDF domains identified in this research as determinants of healthy eating, physical activity and alcohol use behaviours

Becoming differently modern: Geographic contributions to a generative climate politics

Anthropogenic climate change is a quintessentially modern problem in its historical origins and discursive framing, but how well does modernist thinking provide us with the tools to solve the problems it created? On one hand even though anthropogenic climate change is argued to be a problem of human origins, solutions to which will require human actions and engagements, modernity separates people from climate change in a number of ways. On the other, while amodern or more-than-human concepts of multiple and relational agency are more consistent with the empirical evidence of humans being deeply embedded in earth surface processes, these approaches have not sufficiently accounted for human power in climate change, nor articulated generative pathways forward. We argue that recent research in human geography has much to offer because it routinely combines both deconstructive impulses and empirical compulsions (ethnographic, material, embodied, practice-based). It has a rather unique possibility to be both deconstructive and generative/ creative. We bring together more-than-human geographies and cross-scalar work on agency and governance to suggest how to reframe climate change and climate change response in two main ways: elaborating human and non-human continuities and differences, and identifying and harnessing vernacular capacities

Exploring the invasion of rangelands by Acacia mearnsii (black wattle): biophysical characteristics and management implications

Australian acacias have spread to many parts of the world. In South Africa, species such as A. mearnsii and A. dealbata are invasive. Consequently, more effort has focused on their clearing. In a context of increasing clearing costs, it is crucial to develop innovative ways of managing invasions. Our aim was to understand the biophysical properties of A. mearnsii in grasslands as they relate to grass production and to explore management implications. Aboveground biomass (AGB) of A. mearnsii was determined using a published allometric equation in invaded grasslands of the northern Eastern Cape, South Africa. The relationships among the A. mearnsii leaf area index (LAI), normalised difference vegetation index (NDVI) and AGB were investigated. The influence of A. mearnsii LAI and terrain slope on grass cover was also investigated. Strong linear relationships between NDVI, LAI and AGB were developed. Acacia mearnsii canopy adversely impacted grass production more than terrain slope (p < 0.05) and when LAI approached 2.1, grass cover dropped to below 10% in infested areas. Reducing A. mearnsii canopy could promote grass production while encouraging carbon sequestration. Given the high AGB and clearing costs, it may be prudent to adopt the ‘novel ecosystems’ approach in managing infested landscapes.Keywords: grassland, invasive plants, landscape ecology, rangeland conditio

Determining fPAR and leaf area index of several land cover classes in the Pot River and Tsitsa River catchments of the Eastern Cape, South Africa

Determining the quantum (both annual maxima and minima) and the temporal variation in the leaf area index (LAI), and the fraction of photosynthetically active radiation (fPAR), are three fundamental biophysical characteristics of the plant canopy that should parameterise ecophysiological models of water use (evapotranspiration) and carbon sequestration. Although Earth observation provides values and time series for both these parameters, in-field validation of these values is necessary. Following a very wet summer season, we conducted field surveys of several land cover classes within two quaternary catchments in the Eastern Cape province, South Africa, to determine maximum values of LAI and fPAR that occur within each of these land cover classes. To assist in up-scaling these point measures to the landscape, we present a regression relationship between Landsat 8 NDVI and LAI measured using an Accupar Ceptometer (r2 = 0.92). Peak wet season LAI varied from extremely high (>7.0) under the canopy of invasive black wattle (Acacia mearnsii) trees to ~2.0 under the canopy of a Eucalyptus plantation. Ungrazed native grassland displayed an intermediate LAI value of 3.84. The black wattle stand absorbed 97% of the available PAR, whereas the mature Eucalyptus plantation only absorbed 66% of PAR.Keywords: agroforestry, ecosystem ecology, remote sensin