http://hdl.handle.net/10500/7059 2013-05-23T10:48:11Z 2013-05-23T10:48:11Z Kibuka-Sebitosi E. http://hdl.handle.net/10500/7635 2012-11-01T16:31:43Z 2010-01-01T00:00:00Z

Sublethal effects of insecticides on the reproductive success of the Tsetse species Glossina pallidipes and G. m. morsitans Kibuka-Sebitosi E. Female Glossina pallidipes Austen and G. m. morsitans Westwood (Diptera: Glossinidae) were treated with deltamethrin or pyrethrum extract through topical application or by exposure to cloth or glass treated with the same insecticides. Reproductive performance was assessed in terms of survival, pupae number and viability and reproductive deformities and abnormalities within the reproductive systems including abortions. Survival and fecundity of treated flies were significantly reduced (P<0.001). Pupae were small, mostly non-viable, and were arrested at various stages of development. Abortions of egg and all stages of larvae were observed in pregnancy cycles 1-7 following insecticide treatment. Various concentrations ranging from 1-1014 nanograms per micro litre (ng/μL) of insecticide in redistilled acetone topically applied (1μ/fly) on the dorsal thorax of the females, 24 hr after their previous blood meal, resulted in both insecticides in various concentrations causing reproductive abnormalities in both species, including egg reabsorption after ovulation. The sublethal effects were observed to prevent ovulation altogether in some of the flies, which implies effects on the reproductive performances and control strategies for tsetse flies. Sublethal doses could impact negatively on beneficial organisms in the environment where tsetse flies occur mainly riverine, woodlands and forest ecosystems.

2010-01-01T00:00:00Z Mtholeni N.N. http://hdl.handle.net/10500/7633 2012-11-01T16:31:43Z 2010-01-01T00:00:00Z

Zulu Noun Classes Revisited: A Spoken Corpus-Based Approach Mtholeni N.N. [No abstract available]

2010-01-01T00:00:00Z Roos H. http://hdl.handle.net/10500/7634 2012-11-01T16:31:43Z 2010-01-01T00:00:00Z

Art and/as Anarchy: Portraying the artist during times of turmoil and war Roos H. Two South African novels, Congo Song (Cloete [1943]1973) and Moxyland (Beukes 2008) comment on the central part played by artists and their work in the midst of a society on the brink of war. Both narratives are set in Africa; one portrays a close-knit white community in the Congo in 1939, facing the collapse of their colonial way of life, the other depicts the apocalyptic nature of a dystopian Cape Town around 2018, reflecting the global reality of environmental catastrophe, deadly epidemics and state and corporate tyranny. In both texts art and artists play pivotal roles within a group of characters, and their views of their work, the multiple manifestations of creative art and the relationship between their specific communities and what is regarded there as art, form an integral part of the narrative whole. This article focuses on how various textual strategies are exploited to reveal how the creative urge is linked with resistance against as well as support for destructive violence. It also discusses aspects of the novels that are structured to, on the one hand, endorse the quest for romantic aestheticism and, on the other hand, forecast the reign of cyberspace and genetically modified art. 2011 04 15. © JLS/TLW.

2010-01-01T00:00:00Z Matabola K.P. Van Der Merwe E.M. Strydom C.A. Labuschagne F.J.W. http://hdl.handle.net/10500/7632 2012-11-01T16:31:42Z 2010-01-01T00:00:00Z

The influence of hydrating agents on the hydration of industrial magnesium oxide Matabola K.P.; Van Der Merwe E.M.; Strydom C.A.; Labuschagne F.J.W. BACKGROUND: The influence of different hydrating agents on the pH of the hydrating solutions, rate of hydration of MgO to Mg(OH) 2 and product surface area was studied as a function of temperature of hydration. Hydrating agents used were aqueous solutions of ammonium chloride, magnesium acetate, magnesium nitrate, nitric acid, acetic acid, magnesium chloride, sodium acetate and hydrochloric acid and distilled water as control. These were chosen to determine either the effect of addition of a common ion, the effect of changing the solution pH or due to the presence of an acetate ion, found earlier to have a beneficial effect on the hydration of MgO. RESULTS: There was no significant difference in the hydration behaviour of the hydrating agents up to 50 °C, where less than 10% of magnesium hydroxide was formed. The amount of hydroxide increased at temperatures above 60 °C. When compared with the hydration in water, all the hydrating agents, with the exception of sodium acetate, showed a significant increase in the degree of hydration. Sodium acetate formed the lowest amount of magnesium hydroxide, ranging between 1.2 and 12.2% magnesium hydroxide. The largest percentage (56.7%) of magnesium hydroxide was formed from hydration in magnesium acetate. CONCLUSION: It seems that MgO hydration is a dissolution-precipitation process controlled by the dissolution of MgO. The increased degree of hydration in magnesium acetate is possibly due to the presence of acetate and Mg 2+ ions. © 2010 Society of Chemical Industry.

2010-01-01T00:00:00Z