Spherulites : evidence of herding strategies at Mapungubwe

Archaeology MSc Dissertation School of Geography, Archaeology and Environmental Studies Faculty of Science University of the Witwatersrand Johannesburg 2013Agropastoralists during the Iron Age established their settlements in the Limpopo Valley to take advantage of the rich floodplains of the Shashe-Limpopo confluence. Trade in ivory may have been a draw card in the earlier Zhizo period (AD 900), but good climate and increased rainfall helped to maintain a growing population which in turn contributed to the rise of complex society and the first state in southern Africa, i.e. Mapungubwe (AD 1250-1300). The population increase and the concomitant agricultural land use, together with several droughts, would have challenged livestock management. Using carbon signatures, J. Smith (2005) discovered that cattle were sustained on graze alone, indicating sufficient grass in the valley for pasture during the Iron Age. I have used spherulites found in cattle dung to investigate the use of the confluence vlei area. Vlei grass would have provided extra pasturage. I considered time and space to interpret samples. For the Zhizo and Leokwe periods, I examined 13 samples, including Castle Rock, of which six were positive. K2 had nine positive samples out of 17 while Transitional K2 had 20 positives samples. The TK2 results suggest there was a greater need for extra pasturage associated with drought from AD 1220 to 1250. The Mapungubwe period is represented by 11 samples and five yielded positive results while the Khami period yielded 12 positive results out of 26 samples. These results show a regular use of the confluence vlei during the Iron Age associated with dry conditions

Ethnobotanical uses, anatomical features, phytochemical properties, antimicrobial activity, and cytotoxicity of the Sotho medicinal plant Searsia erosa (Anacardiaceae)

Abstract : Please refer to full text to view abstract.M.Sc. (Botany

Tuberculosis (TB) treatment outcomes in adult TB patients attending a rural HIV cllinic in South Africa (Bushbuckridge).

MSc (Med), Epidemiology and Biostatistics, Faculty of Health Sciences, University of the Witwatersrand, 2009South Africa is ranked fourth on the list of 22 high-burden TB countries in the world. Intensifying the prevalence of TB in South Africa is the high TB/HIV co-infection rate, with 44% of new TB patients testing positive for HIV. This burden is intense for rural communities due to poverty and return of people with TB/HIV co-infection who previously migrated for employment. In rural South Africa, TB is the leading cause of mortality in HIV-infected persons, but limited information is available about predictors of death. This study measures TB treatment outcomes in Rixile clinic and assesses predictors of TB mortality. Rixile HIV clinic is based in Tintswalo hospital, Acornhoek, Bushbuckridge, Mpumalanga province. This current study uses secondary data collected through a prospective cohort study conducted by PHRU and RADAR from March 2003 to March 2008 on 3 to 6 monthly intervals. Chi-square and logistic regression statistical tests were used to assess predictors of TB Mortality. TB mortality among study participants was 62.5% during the pre-ARV rollout period (March 2003- October 2005), and treatment completion was 31.7%. Some 5.8% participants interrupted treatment during the pre-ARV rollout period as compared to 4.5% during the ARV rollout period (November 2005- March 2008). TB mortality among study participants was 7.5% during ARV rollout and treatment completion increased to 84.4%. Factors associated with TB mortality were age (p=0.006), sex (p=0.017), BMI (p< 0.001), marital status (p=0.004), education (p=0.03), alcoholic beverages consumption (p=0.04), and ARV treatment (p<0.001). However, only age, sex, and ARV treatment were found to predict TB mortality. The proportion of TB treatment completion was higher and TB mortality was lower during ARV roll-out compared to pre-ARV roll-out. Being at the age of 40 to 75 years, not being on ARV treatment and male sex predicts TB mortality in this population. There is a need to expand ARV treatment and intensify TB care services for older people, particularly males living with HIV in this rural community

Isolation and identification of possible analgesics and antihypertensive agents from antidesma venosum

This investigation originated from a suggestion by Noristan Laboratories, Pretoria, that because Black people were using the roots of A. venosum E. MEY. ex. TUL for treating headache, the plant might contain analgesics. No previous chemical investigation has been carried out on this plant but from previous work done on other species antihypertensive agents were expected to be presen

Chemical constituents of plants native to Venda.

Abstract available in pdf file

A New Flavonol from Athrixia phylicoides (Bush Tea)

Athrixia phylicoides (bush tea), belonging to the Asteraceae family, is a popular beverage used as a herbal tea and for medicinal purposes. The processed leaves of bush tea contain 5-hydroxy-6,7,8,3’,4’,5’-hexamethoxyflavon-3-ol as major flavonoid.KEYWORDS: Athrixia philicoides, bush tea, flavonoids, health beverage, phenols

Assessing the influence of DEM source on derived streamline and catchment boundary accuracy

Accurate DEM-derived streamlines and catchment boundaries are essential for hydrological modelling. Due to the popularity of hydrological parameters derived mainly from free DEMs, it is essential to investigate the accuracy of these parameters. This study compared the spatial accuracy of streamlines and catchment boundaries derived from available digital elevation models in South Africa. Two versions of Stellenbosch University DEMs (SUDEM5 and DEMSA2), the second version of the 30 m advanced spaceborne thermal emission and reflection radiometer global digital elevation model (ASTER GDEM2), the 30 and 90 m shuttle radar topography mission (SRTM30 and SRTM90 DEM), and the 90 m Water Research Commission DEM (WRC DEM) were considered. As a reference, a 1 m GEOEYE DEM was generated from GeoEye stereo images. Catchment boundaries and streamlines were extracted from the DEMs using the Arc Hydro module. A reference catchment boundary was generated from the GEOEYE DEM and verified during field visits. Reference streamlines were digitised at a scale of 1:10 000 from the 1 m orthorectified GeoEye images. Visual inspection, as well as quantitative measures such as correctness index, mean absolute error, root mean squares error and figure of merit index were used to validate the results. The study affirmed that high resolution (&lt;30 m) DEMs produce more accurate parameters and that DEM source and resampling techniques also play a role. However, if high resolution DEMs are not available, the 30 m SRTM DEM is recommended as its vertical accuracy was relatively high and the quality of the streamlines and catchment boundary was good. In addition, it was found that the novel Euclidean distancebased MAE and RMSE proposed in this study to compare reference and DEM-extracted raster datasets of different resolutions is a more reliable indicator of geometrical accuracy than the correctness and figure of merit indices.Keywords: hydrology, catchment delineation, digital elevation model, correctness index, figure of merit index, Euclidean distance inde

A synthesizing land-cover classification method based on Google Earth Engine : a case study in Nzhelele and Levhuvu catchments, South Africa

CITATION: Zeng, H. et al. 2020. A Synthesizing Land-cover Classification Method Based on Google Earth Engine: A Case Study in Nzhelele and Levhuvu Catchments, South Africa. Chinese Geographical Science. 30: 397–409. doi:10.1007/s11769-020-1119-yThe original publication is available at https://www.springer.com/journal/11769This study designed an approach to derive land-cover in the South Africa with insufficient ground samples, and made a case demonstration in Nzhelele and Levhuvu catchments, South Africa. The method was developed based on an integration of Landsat 8, Sentinel-1, and Shuttle Radar Topography Mission (SRTM) Digital Elevation Model (DEM), and the Google Earth Engine (GEE) platform. Random forest classifier with 300 trees is employed as land-cover classification model. In order to overcome the defect of insufficient ground data, the stratified sampling method was used to generate the training and validation samples from the existing land-cover product. Likewise, in order to recognize different land-cover categories, the percentile and monthly median composites were employed to expand input metrics of random forest classifier. Results showed that the overall accuracy of the land-cover of Nzhelele and Levhuvu catchments, South Africa in 2017–2018 reached to 76.43%. Three important results can be drawn from our research. 1) The participation of Sentinel-1 data can slightly improve overall accuracy of land-cover while its contribution on land-cover classification varied with land types. 2) Under-fitting problem was observed in the training of non-dominant land-cover categories using the random sampling, the stratified sampling method is recommended to make sure the classification accuracy of non-dominant classes. 3) When related reflectance bands participated in the training process, individual Normalized Difference Vegetation index (NDVI), Enhanced Vegetation Index (EVI), Soil Adjusted Vegetation Index (SAVI), Normalized Difference Built-up Index (NDBI) have little effect on final land-cover classification result.https://link.springer.com/article/10.1007/s11769-020-1119-yPublishers versio

Survey of community livelihoods and landscape change along the Nzhelele and Levuvhu river catchments in the Limpopo Province, South Africa

Abstract:Landscape change studies have attracted increasing interest because of their importance 29 to land management and sustainable livelihoods of rural communities. However, empirical studies 30 on landscape change and its drivers are often poorly understood, particularly, in small rural 31 communities in developing countries such as South Africa. The present study surveyed local 32 community livelihoods and perceptions of landscape change in the Nzhelele and Levuvhu river 33 catchments in Limpopo Province, South Africa. These areas have experienced land reform and are 34 also characterized by environmental degradation, poverty, inequality and environmental justice 35 concerns among other issues. Land cover maps derived from Landsat satellite imagery were used 36 for purposes of correlating and validating the survey data findings and results. The survey results 37 showed that education levels, working status and marital status have statistically significant effects 38 on community livelihoods (indicated by levels of income, p < 0.05). Maize, fruits and vegetables are 39 the main cultivated crop varieties in the study area, and these crops are mainly used for subsistence 40 to meet household self-consumption requirements.

Phytochemical characterization of South Africa bush tea (Athrixia phylicoides DC.)

A methanolic extract of bush tea (Athrixia phylicoides, Asteraceae) was evaluated sensorially. A High Temperature Liquid Chromatography (HTLC)-coupled sensory-guided analysis was performed on bush tea extract to identify potential taste modulating compounds. One fraction showed bitter enhancing effects on caffeine. Fractionated using Fast Centrifugal Partition Chromatography (FCPC) and preparative HPLC followed by structure elucidation using NMR and LC-NMR led to the identification of three polymethoxylated flavones, quercetin-3'- O-glucoside (1), as well as a methoxylated derivative (2). In addition, two dicaffeoyl quinic acids and one coumaric acid ester (3) were isolated. Sensory evaluation of isolated compounds led to the identification of quercetin-3'-O-glucoside as bitterness enhancing principle.http://www.elsevier.com/locate/sajbhb201