Investigating the relationship between coal usage and the change in cations and sulphate fluxes in three rivers in the Waterberg, South Africa

The Matimba and soon to be completed Medupi power stations located in close proximity to the town of Lephalale are a cause for environmental concern due to the known effects that coal combustion has on air, soil and water quality. The Medupi power station is currently being constructed, while the Matimba power station may have already negatively altered the water quality of the rivers especially those downwind of the power stations. The Lephalala (perennial river, upwind), the Mokolo (perennial river, upwind) and Matlabas (seasonal river, downwind) Rivers were selected due to the locations relative to the power stations. The concentrations and flux of cations and sulphate ions within the rivers in the Waterberg District Municipality were investigated for any seasonal or annual patterns using monthly data from a single sampling station along each river. Data for the concentrations of sodium, potassium, magnesium, calcium, ammonium and sulphate were analysed in conjunction with river discharge, rainfall and ambient temperature data available for each hydrological year from 1999 to 2010. The data were converted to seasonal and annual values in order to determine the influence of the quality and quantity of coal combusted as well as climatic variables (rainfall, temperature and discharge) on ion fluxes measured. Sodium was the dominant cation in all rivers, reaching a maximum concentration of 0.0015 mol.ℓ-1 (in 2007), 0.0007 mol.ℓ-1 (in 2007) and 0.0006 mol.ℓ-1 (in 2001) in the Lephalala, Mokolo and Matlabas Rivers, respectively. Other cation concentrations were four times lower in the Lephalala and Mokolo Rivers, while they were eight times lower in the Matlabas Rivers. Sulphate concentrations were approximately nine, five and 15 times lower than the cation concentrations measured within the Lephalala, Mokolo and Matlabas Rivers, respectively. The mean summed cation flux was highest in the Lephalala River (0.0015 ± 0.0010 Eq.ℓ-1), which was approximately 1.7 and 2.1 times higher than summed cation fluxes measured in the Mokolo (0.0009 ± 0.0002 Eq.ℓ-1) and Matlabas (0.0007 ± 0.0006 Eq.ℓ-1) Rivers. Cation fluxes were highest during the rainfall season (summer and spring) in the river closest to the Matimba power station (Mokolo Rivers) while summed cation flux in the Lephalala and Mokolo Rivers (located further away from the power station) showed no specific seasonality. It was, however, noted that the cation fluxes during spring and winter were elevated for both rivers, possibly indicatin

Perceptions of race of coloured children in a child and youth care centre

Includes abstract.Includes bibliographical references.This study was an exploration into the perceptions of race of coloured children in a child and youth care centre, Leliebloem House. The aim of this study was to evaluate the ways in which race is still present in the lives of these children, who were supposedly “untouched” by the former Apartheid dispensation

Huernia humpatana (Apocynaceae), a new species from southern Angola

AbstractA new species, Huernia humpatana Bruyns (Apocynaceae–Ceropegieae), closely related to H. similis N.E.Br., is described from the Chela Mountains of Huila Province in southern Angola. The two species are distinguished by the 5-angled and erect stems with more prominent tubercles up to 6mm long joined into clear angles and separated by V-shaped grooves in H. humpatana as opposed to very obtusely 4-angled stems with tubercles only 2mm long and only indistinct grooves between the angles in H. similis. Furthermore, in H. similis the nodding corolla is ±9mm in diameter with sepals ±2mm long, while in H. humpatana the horizontally facing corolla is 18–20mm in diameter with sepals 4–6mm long

A new species of Caralluma (Apocynaceae-Asclepiadoideae-Ceropegieae) from the Yemen

In this paper a new species, Caralluma faucicola Bruyns, closely related to C. hexagona Lavranos, is described from near the border between the former North and South Yemen in Arabia

Hybridity: an urban response to a crisis of identity sameness

Architectural character is currently facing a crisis of sameness, as individual regional architectural identities are being subsumed into a greater global capitalist culture. This is resulting in loss of diversity and difference in urban life. With the dominance of commercial development in urban environments around the world, there is a disproportionate relationship between public and private space. The general public is being forced to operate solely within the private realm. This essay discusses this phenomenon, recently referred to as McDonaldisation. While many architects design utopian cities and lifestyles, few have undertaken the task of developing these concepts into realistic projects. This study attempts to bridge this gap between architectural idealism and social reality by developing a hybrid architectural outcome that improves social conditions while simultaneously facilitating commercial practice and the need for profitability in architecture. A review of architectural and sociopolitical literature reveals the necessity of approaching this debate from a multiperspectivist viewpoint for the creation of hybrid theoretical and architectural responses which engage with the everyday. This paper describes briefly the history of hybrids and examines three case studies of mixed-use buildings to more clearly illustrate the meaning of the term hybrid, in the architectural context. A solution is posed to this problem through the creation of new hybridised development models which engage the public realm on a substantive level

The systematic position of Rhytidocaulon (Apocynaceae-Asclepiadoideae)

Rhytidocaulon P.R.O. Bally is reviewed. The relationships with other genera are discussed in the light of the character assessment carried out and it is suggested that it is closest to Caralluma R. Br. subg. Caralluma and Echidnopsis Hook. f. Descriptions of the genus and the eight known species are provided

A revision of Hoodia and Lavrania (Asclepiadaceae-Stapelieae)

Hoodia Sweet ex Decne is revised to contain 13 species which are divided into 2 sections. Sect. Hoodia contains H.currorii, H.dregei, H.gordonii, H.juttae and H.parviflora. Sect. Trichocaulon contains H.alstonii, H.flava, H.mossamedensis, H.officinalis, H.pedicellata, H.pilifera, H.ruschii and H.triebneri, all except H.ruschii formerly constituting the section "Eutrichocaulon", the so-called "spiny" species of Trichocaulon. The remainder of Trichocaulon, the section Cactoidea, is transferred to Lavrania Plowes. This genus then consists of the monotypic section Lavrania (L.haagnerae) and Sect. Cactoidea containing L.cactiformis, L.marlothii, L.perlata and L.picta