Drought, change and resilience in South Africa's arid and semi-arid rangelands
- Authors: Vetter, Susan M
- Date: 2009
- Language: English
- Type: Article
- Identifier: vital:6557 , http://hdl.handle.net/10962/d1006017
- Description: Droughts can have serious ecological and economic consequences and will pose an increasing challenge to rangeiand users as the global climate is changing. Finding ways to reduce ecological and economic impacts of drought should thus be a major research thrust. Resilience, defined as the amount of perturbation a social or ecological system can absorb without shifting to a qualitatively different state, has emerged as a prominent concept in ecosystem ecology and more recently as a conceptual framework for understanding and managing complex social-ecological systems. This paper discusses the application and relevance of resilience to understanding and managing ecosystem change, and enhancing the capacity of land users to adapt to droughts. Drought can trigger vegetation change and factors such as grazing management can influence the likelihood of such transitions. Drought can cause differential mortality of perennial plants and this could provide an opportunity for rangeland restoration by opening up establishment sites for desirable species. The capacity of land users to cope with drought is influenced by the resilience of their agro-ecosystems, the diversity of livelihood options, access to resources and institutional support. By these criteria, current agricultural development approaches in South Africa, particularly in communal rangelands and areas of land reform, are unlikely to enhance land users' resilience to drought and other perturbations.
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- Date Issued: 2009
Effect of laundry activities on in-stream concentrations of linear alkylbenzene sulfonate in a small rural South African river
- Authors: Gordon, Andrew K , Muller, Wilhelmine J , Gysman, N , Marshall, S J , Sparham, C J , O'Connor, S M , Whelan, M J
- Date: 2009
- Language: English
- Type: text , Article
- Identifier: vital:7094 , http://hdl.handle.net/10962/d1012427
- Description: In many parts of the world clothes are washed near to or in rivers and streams. Little information is available on resulting concentrations of detergent ingredients or on any potential effects caused. In this study, the fate of a commonly used anionic surfactant, linear alkylbenzene sulphonate (LAS) was investigated in a reach of the Balfour River (Eastern Cape Province, South Africa) which was regularly used as a site for laundry activity. Samples of river water were collected upstream of the main washing site and at a number of locations downstream on several occasions in winter and summer. Sediment samples were also collected and analysed. In addition, a household survey was conducted to ascertain the amount of detergent used and the distribution of washing practices. The results of the survey suggested that the use of riverside locations for laundry activities was seasonal. Most washing tended to be done at home during the winter with riverside sites used more frequently during the summer months. The monitoring data showed that LAS concentrations in water were very variable. They were occasionally high in the immediate vicinity of the laundry site (up to 342 µg L− 1) but were generally very low (< 11 µg L− 1) at downstream monitoring stations, suggesting that LAS was rapidly dissipated by a combination of degradation, hydrodynamic dispersion and dilution. Concentrations in the immediate vicinity of the washing site were lower than expected on the basis of the household survey because most waste water was disposed of on the river bank rather than directly in the river. No ecological effects are expected from LAS emissions at this site.
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- Date Issued: 2009
Effect of the killing method on post-mortem change in length of larvae of Thanatophilus micans (Fabricius, 1794) (Coleoptera: Silphidae) stored in 70% ethanol
- Authors: Midgley, John M , Villet, Martin H
- Date: 2009
- Language: English
- Type: text , Article
- Identifier: vital:6857 , http://hdl.handle.net/10962/d1011140
- Description: It is recommended that insect larvae collected for forensic purposes should be killed using the same method as was used to create existing models for rate of development. Certain killing methods have been shown to be preferable because they cause less distortion of the specimens, but these are not always practicable in a particular case, and so a method of correcting for effect of killing method is required. Larvae of all instars of Thanatophilus micans (Fabricius 1794) (Coleoptera: Silphidae) were measured and then killed by immersion in ethanol, immersion in hot water or freezing. Samples were re-measured immediately after death, then stored in excess 70% ethanol and re-measured after 1 week and again after 4 weeks. The change in length was significantly different from zero in all samples (t = -9.07022, p < 0.001). An analysis of covariance showed that instar, killing method and storage time all had a significant effect on the change in length. The results showed that T. micans larvae have a great potential for change in length during storage but that the change is not predictable, as the magnitude and sign of the change are variable.
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- Date Issued: 2009
Efficacy of solar power units for small-scale businesses in a remote rural area, South Africa
- Authors: Hajat, A , Banks, D , Aiken, R , Shackleton, Charlie M
- Date: 2009
- Language: English
- Type: Article
- Identifier: vital:6636 , http://hdl.handle.net/10962/d1006860
- Description: Much work has considered the practicalities and affordability of solar systems for domestic energy supplies in remote rural areas. There is less understanding of its utility for small-scale business enterprises in such areas. We examined the patterns of use of two 12 V and one 24 V systems for small-scale enterprises housed in transportable containers. Monitoring of load shed and top of charge indicated that the 12 V systems were inadequate to meet the requirements of the enterprises. The 24 V operation performed a lot better. Despite some technical limitations the system offered a number of social, economic and environmental positives; primarily the offering of business products not otherwise available in the area, incomes to the entrepreneurs and greater connectivity with regional centres through office services such as cell-phone charging and faxing. Customers of the small-scale enterprises felt that their presence in the area saved them some money because they no longer had to travel as frequently to regional urban centres.
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- Date Issued: 2009
Elections: a dangerous time for poor people's movements in South Africa
- Authors: Pithouse, Richard, 1970-
- Date: 2009
- Language: English
- Type: Article
- Identifier: vital:6203 , http://hdl.handle.net/10962/d1008572
- Description: [From introduction]: History groans with the suffering caused by authoritarian individuals and regimes that were elected to power. For this reason the only useful measure of the commitment of any political project to democracy is to see how it responds to challenges to its own position and ideas.
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- Date Issued: 2009
Epistemological access as an open question in education
- Authors: Lotz-Sisitka, Heila
- Date: 2009
- Language: English
- Type: Article
- Identifier: vital:21219 , http://hdl.handle.net/10962/7123 , http://joe.ukzn.ac.za/Libraries/No_46_June_2009/Epistemological_access_as_an_open_question_in_education.sflb.ashx
- Description: In his book Learning to Teach in South Africa Morrow (2007)1 argues that teacher education’s ultimate aim is to enable epistemological access2 to knowledge in the modern world, and that there is a need to find new ways of thinking about teaching in South Africa if we are to meet the challenge of enabling all learners to gain such epistemological access. Morrow relates problems of epistemological access to the dominance of an empiricist epistemology in education, and he also comments on how this is obscured by the ideologies of Outcomes Based Education and learner-centred education (with attendant constructivist, relativist assumptions about knowledge). These problems, he argues, have come to shape curriculum thinking, and hence teaching practice, creating a muddled epistemological context in which teaching practices are taking place. He argues for a realist focus but he does not elaborate on what such a realist focus might mean for enabling epistemological access or for associated teaching practice or for teacher education. He does, however, propose that systematic learning is a necessary way forward.
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- Date Issued: 2009
Evaluating the IRI topside model for the South African region: An overview of the modelling techniques
- Authors: Sibanda, Patrick , McKinnell, Lee-Anne
- Date: 2009
- Language: English
- Type: text , Article
- Identifier: vital:6810 , http://hdl.handle.net/10962/d1004303
- Description: The representation of the topside ionosphere (the region above the F2 peak) is critical because of the limited experimental data available. Over the years, a wide range of models have been developed in an effort to represent the behaviour and the shape of the electron density (Ne) profile of the topside ionosphere. Various studies have been centred around calculating the vertical scale height (VSH) and have included (a) obtaining VSH from Global Positioning System (GPS) derived total electron content (TEC), (b) calculating the VSH from ground-based ionosonde measurements, (c) using topside sounder vertical Ne profiles to obtain the VSH. One or a combination of the topside profilers (Chapman function, exponential function, sech-squared (Epstein) function, and/or parabolic function) is then used to reconstruct the topside Ne profile. The different approaches and the modelling techniques are discussed with a view to identifying the most adequate approach to apply to the South African region’s topside modelling efforts. The IRI-2001 topside model is evaluated based on how well it reproduces measured topside profiles over the South African region. This study is a first step in the process of developing a South African topside ionosphere model.
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- Date Issued: 2009
Fluorescence studies of quantum dots and zinc tetraamino phthalocyanine conjugates
- Authors: Britton, Jonathan , Antunes, Edith M , Nyokong, Tebello
- Date: 2009
- Language: English
- Type: Article
- Identifier: vital:6565 , http://hdl.handle.net/10962/d1004124
- Description: CdTe Qds capped with mercapto propionic acid (MPA) were covalently linked to zinc tetraamino phthalocyanine (ZnTAPc) using N-ethyl-N(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxy succinimide (NHS) as the coupling agents. The results presented give evidence in favour of the formation of an amide bond between ZnTAPc and CdTe QDs. Both the linked ZnTAPc–QD complexes and a mixture of QDs and ZnTAPc (i.e. without chemical linking) showed Förster resonance energy transfer (FRET). ZnTAPc quenched the QDs emission, giving quenching constants in the order of 103 M−1.
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- Date Issued: 2009
Geomorphology and dynamics of the Mfolozi River floodplain, KwaZulu-Natal, South Africa
- Authors: Grenfell, Suzanne E , Ellery, William F N , Grenfell, Michael C
- Date: 2009
- Language: English
- Type: Article
- Identifier: vital:6633 , http://hdl.handle.net/10962/d1006827
- Description: The geomorphology and dynamics of the Mfolozi River floodplain and estuary, located in the subtropical region of northern KwaZulu-Natal, South Africa, were considered with respect to existing models of avulsion and alluvial stratigraphy. The Mfolozi River floodplain may be divided into regions based on longitudinal slope and dominant geomorphic processes. Confinement of the Mfolozi River above the floodplain has led to the development of an alluvial fan at the floodplain head, characterized by a relatively high sedimentation rate and avulsion frequency, at a gradient of 0.10%. The lower floodplain is controlled by sea level, with an average gradient of 0.05%. Between the two lies an extremely flat region with an average gradient of 0.02%, which may be controlled by faulting of the underlying bedrock. Avulsion occurrences on the Mfolozi floodplain are linked to the two main zones of aggradation, the alluvial fan at the floodplain head, and toward the river mouth in the lower floodplain. On the alluvial fan, normal flow conditions result in scour from local steepening. During infrequent, large flood events, the channel becomes overwhelmed with sediment and stream flow, and avulses. The resulting avulsion is regional, and affects the location of the channel from the floodplain head to the river mouth. Deposits resulting from such avulsions contribute significantly to the total volume of sediment stored in the floodplain, and tend to persist for long periods after the avulsion. Contrastingly, on the lower floodplain, reaching of the avulsion threshold is not necessarily linked to large flood events, but rather to long-term aggradation on the channel that decreases the existing channels gradient while increasing its elevation above the surrounding floodplain. Resultant avulsions tend to be local and do not contribute significantly to the overall volume of floodplain alluvium.
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- Date Issued: 2009
Hold the prawns
- Authors: Pithouse, Richard, 1970-
- Date: 2009
- Language: English
- Type: Article
- Identifier: vital:6206 , http://hdl.handle.net/10962/d1008576
- Description: [From introduction]: In the cities of the global South elites are often desperate to repress the reality of the shack settlement. Maps are printed in which shack settlements appear as blank spaces, laws are passed that assume that everyone can afford to live formally and, in the name of order and development, the poor are beaten out of the cities. The great elite fantasy is the creation of 'world class cities' – shiny, securitised nowherevilles in which the poor understand that their place is to live in some peripheral ghetto and only come into the city as menial workers. But from City of God to Slum Dog Millionaire and now District 9 cinema has put the shack settlement in the mall and at the heart of how Rio, Bombay and Johannesburg feature in the global imagination.
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- Date Issued: 2009
Hydrology, sediment transport dynamics and geomorphology of a variable flow river : the Mfolozi River, South Africa
- Authors: Grenfell, Suzanne E , Ellery, William F N
- Date: 2009
- Language: English
- Type: Article
- Identifier: vital:6632 , http://hdl.handle.net/10962/d1006826
- Description: The co-efficient of variation for inter-annual streamflow of the Mfolozi River is extremely high at 79%. An analysis of flow frequency indicated that streamflow is skewed towards low-flow values, with a number of extremely large flood events occurring as outliers on the histogram. Streamflow variability in the Mfolozi River may be linked to multiple factors including a large catchment size, a seasonal climate of a dry winter and wet summer, evergreen vegetation in the catchment, variable precipitation and the occurrence of regionally pervasive climatic oscillations. This research aimed to address how streamflow variability impacted upon sediment transport and thus, geomorphology. It was found that sediment transport variability occurred at the intra-and inter-annual scale. Analysis of mean monthly sediment concentration and discharge showed a hysteresis effect, such that sediment concentration peaked prior to discharge in the early wet season. During the late wet season, peak discharges often had unexpectedly low sediment concentrations. Furthermore, data suggested the existence of long-term hysteresis that may be related to decadal-scale climatic oscillations that alter sediment availability and stream capacity, resulting in discharge peaking in 2000 and sediment concentration in 2005. However, more data are required to confirm this relationship. Variability in streamflow appears to share a causal relationship with sediment transport variability, as both are linked to variation in precipitation and the resultant impacts on vegetation growth and evapotranspiration rates. The variability of streamflow and sediment transport has implications for stream and floodplain geomorphology, and the hydrology of variable rivers should be considered when interpreting their geomorphology.
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- Date Issued: 2009
Intellectual challenge is as necessary as breathing: an interview with Laurence Wright
- Authors: Wright, Laurence , Pearce, B
- Date: 2009
- Language: English
- Type: text , Article
- Identifier: vital:7059 , http://hdl.handle.net/10962/d1007422
- Description: Professor Laurence Wright is Director of the Institute for the Study of English in Africa at Rhodes University. In 2009, he will have completed 25 years of research, teaching and scholarship at Rhodes University and this interview marks the occasion. A Rhodes Scholar and a Commonwealth Scholar, he studied at the universities of Rhodes, Warwick and Oxford. He is also Honorary Life President of the Shakespeare Society of Southern Africa. He has published widely in literary studies and is the Managing Editor of two academic journals as well as of the poetry magazine New Coin. He currently serves on the Council of the English Academy and is a co-opted member of the English National Language Body. He has taken a broad interest in the role of English in this country, ranging from language policy and teacher education matters, to archival research and the role of the humanities in public life. I thought that it would be worthwhile to interview him as his knowledge of literature is substantial, while his incisive and engaging thoughts on a range of topics are worth hearing. The interview was conducted intermittently by email between July and October, 2008.
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- Date Issued: 2009
Intra- and interspecific brood recognition in pure and mixed-species honeybee colonies, Apis cerana and A. mellifera
- Authors: Tan, K , Yang, M-X , Radloff, Sarah E , Yu, Y , Pirk, Christian W W , Hepburn, H Randall
- Date: 2009
- Subjects: Apis mellifera Apis cerana
- Language: English
- Type: text , Article
- Identifier: vital:6837 , http://hdl.handle.net/10962/d1010962 , http://dx.doi.org/10.1051/apido/2009003
- Description: We studied the effects of mixed honeybee colonies of Apis mellifera and Apis cerana on the intraspecific and interspecific recognition of female brood stages in the honeybees A. cerana and A. mellifera by transferring brood combs between queenright colonies. In the intraspecific tests, significantly more larvae were removed in A. cerana than in A. mellifera, whilst significantly fewer eggs and pupae were removed in A. cerana than in A. mellifera. In the interspecific tests, A. cerana colonies removed significantly more larvae and pupae of A. mellifera than the same brood stages of A. cerana were removed by A. mellifera. We show there are highly significant differences in both intraspecific and interspecific brood recognition between A. cerana and A. mellifera and that brood recognition operates with decreasing intensity with increasing developmental age within species. This suggests that worker policing in egg removal is a first line of defense against heterospecific social parasites.
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- Date Issued: 2009
Investigating how the attributes of live theatre productions influence consumption choices using conjoint analysis : the example of the National Arts Festival, South Africa
- Authors: Willis, K G , Snowball, Jeanette D
- Date: 2009
- Language: English
- Type: Article
- Identifier: vital:6075 , http://hdl.handle.net/10962/d1003825 , http://dx.doi.org/10.1007/s10824-009-9097-z
- Description: While there is a fair amount of work on determinants of demand for the live performing arts, results have often been contradictory with little explanatory power. This may be because of the difficulty in describing the attributes of a performance, particularly in terms of its quality, and the heterogeneity of consumer preferences. This article uses conjoint analysis, also called choice experiments, to investigate the impact of the attributes of live theatre performances on demand, using data collected from 483 randomly chosen attenders at live theatre performances at the 2008 South African National Arts Festival. Attributes include the type of cast (professional, semi-professional or amateur), reputation of the producer/director, the context or setting, production type and ticket price of the show. Results largely support the a priori expectations based on the results of other demand studies. For example, it is found that the age of consumers affects the type of show chosen, that utility and willingness to pay increase for shows with professional and semi-professional casts and that 93% of the potential audience prefer shows with a South African context. It is concluded that the method could prove useful to both event organisers and policy makers, especially where the goal is to broaden access to the arts.
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- Date Issued: 2009
Is HIV/AIDS jeopardizing biodiversity?
- Authors: McGarry, Dylan K , Shackleton, Charlie M
- Date: 2009
- Language: English
- Type: Article
- Identifier: vital:6642 , http://hdl.handle.net/10962/d1006871
- Description: The scourge of HIV/AIDS (human immunodeficiency virus/acquired immune deficiency syndrome) is most prevalent in southern Africa. South Africa has the highest number of people in the world living with HIV/AIDS and a prevalence rate of over 30 % for females presenting at antenatal clinics. There are now almost five million orphans within southern Africa, as a result of AIDS deaths of one or more or their parents. AIDS-related mortality and morbidity of care-givers may lead to increased reliance on wild sources of animal protein by surviving children. This increase in hunting pressure has unknown, but potentially important impacts on local animal populations.
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- Date Issued: 2009
Jimmy Riadore: organ-builder, bell-ringer and hanger of the bells at St George's Cathedral, Cape Town
- Authors: Lewis, Colin A
- Date: 2009
- Language: English
- Type: Article
- Identifier: vital:6190 , http://hdl.handle.net/10962/d1012396
- Description: Born in Lewes, Sussex, Jimmy Riadore came to South Africa in 1958. Organs, bells and clocks have been the focus of his life, and he has tuned, built, repaired and restored them all over southern Africa. Recently he has extended his careful ministrations to St Helena. , Colin Lewis was Professor of Geography at Rhodes University, Grahamstown, South Africa from 1989 until his retirement at the end of 2007. In 1990, with the strong support of the incumbent Vice-Chancellor, Dr Derek Henderson, he instigated the Certificate in Change Ringing (Church Bell Ringing) in the Rhodes University Department of Music and Musicology - the first such course to be offered in Africa. Since that date he has lectured in the basic theory, and taught the practice of change ringing. He is the Ringing Master of the Cathedral of St Michael and St George, Grahamstown, South Africa.
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- Date Issued: 2009
Land occupation and the limits of party politics
- Authors: Pithouse, Richard, 1970-
- Date: 2009
- Language: English
- Type: Article
- Identifier: vital:6200 , http://hdl.handle.net/10962/d1008565
- Description: In the recent election the DA, together with COPE, made much of their intention to defend the rule of the law. But while the dust thrown up in that election is still settling, the City of Cape Town is already engaged in violent and unlawful behaviour towards its most vulnerable citizens.
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- Date Issued: 2009
Luminescence lifetime components in quartz: influence of irradiation and annealing
- Authors: Chithambo, Makaiko L , Ogundare, F O
- Date: 2009
- Language: English
- Type: Article
- Identifier: vital:6811 , http://hdl.handle.net/10962/d1004304
- Description: Pulsed optically stimulated luminescence measured from quartz under certain combinations of annealing and measurement temperature can be resolved into multiple lifetime components. We have studied the influence on these lifetime components of annealing temperature up to 900 °C, beta irradiation dose as high as 1700 Gy, and temperature of stimulation up to 200 °C. Although the time-resolved spectra from which the lifetimes are determined may be measured without heating between irradiation and measurement, a necessary protocol in steady-state optical stimulation applications, studies reported in this paper have been augmented with investigations on the effect of temperature and duration of preheating on the principal and secondary lifetimes. Luminescence spectra for measurements up to 200 Gy consist of a single lifetime but two components occur thereafter, both are independent of radiation dose. The principal lifetime of 35 μs is not affected by temperature of anneal whereas the secondary lifetime increases from 9 to 18 μs when the annealing temperature is changed from 600 to 900 °C. The dependence of both the principal and secondary luminescence lifetimes on measurement temperature can be explained by thermal quenching of the associated luminescence. However, the influence of irradiation, preheating, and annealing on the lifetimes can be explained with reference to an energy band scheme in which the primary mechanism in the processes leading up to luminescence emission is the change in concentration of holes at various luminescence centres caused by annealing.
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- Date Issued: 2009
Municipal commonage policy and livestock owners : findings from the Eastern Cape, South Africa
- Authors: Davenport, Nicholas A , Gambiza, James
- Date: 2009
- Language: English
- Type: Article
- Identifier: vital:6628 , http://hdl.handle.net/10962/d1006820
- Description: The new African National Congress government announced after 1994 that municipal commonage would be a pillar of their land reform programme. The Department of Land Affairs spearheaded this by acquiring new land to complement the existing ‘old’ commonages. The aim of old commonage was to supplement the income of poor urban residents through the subsistence user system whereas new commonage was intended as a ‘stepping stone’ for emergent farmers. We investigated the differences between old and new commonage farmers as well as how they perceived the Makana local municipality's capacity to manage the commonage. The results showed that local institutions were weak. Only 46% of the old commonage farmers were members of a local livestock association whereas 74% of the new commonage farmers were members. Most old commonage farmers (59%) were dissatisfied with local government's management of the commonage. In contrast, only 37% of the new commonage farmers were dissatisfied with the management of the commonage. There were no differences between old and new commonage farmers in terms of livestock owners’ characteristics and mean annual net direct-use value of livestock. There were also no differences in the age of the two types of commonage farmers. Furthermore, there was no association between the type of commonage and level of education. The mean annual net direct-use value of livestock on old commonage was R6308 compared with R9707 on new commonage. Although the income from livestock for new commonage farmers varied slightly from that of old commonage farmers, the annual productive output per farmer on old commonage was R473 ha−1, three times higher than that of new commonage farmers which was R134 ha−1. We suggest that new land policy legislation is needed in which poverty as well as the legal arrangements between all stakeholders is clearly defined. Furthermore, national departments need to be more involved with local municipalities to increase local management capacity.
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- Date Issued: 2009
New soluble methylendioxy-phenoxy-substituted zinc phthalocyanine derivatives : synthesis, photophysical and photochemical studies
- Authors: Erdoğmuş, Ali , Nyokong, Tebello
- Date: 2009
- Language: English
- Type: Article
- Identifier: vital:6572 , http://hdl.handle.net/10962/d1004135
- Description: The syntheses of new three phthalonitriles (1, 2 and 3), together with photophysical and photochemical properties of the resulting peripherally and non-peripherally tetrakis- and octakis 3,4-(methylendioxy)-phenoxy-substituted zinc phthalocyanines (4, 5 and 6) are described for the first time. Complexes 4, 5 and 6 have been synthesized and characterized by elemental analysis, IR, 1H NMR spectroscopy, electronic spectroscopy and mass spectra. Complexes 4, 5 and 6 have good solubility in organic solvents such as CHCl3, DCM, DMSO, DMF, THF and toluene and are mainly not aggregated (except for complex 6 in DMSO) within a wide concentration range. General trends are described for singlet oxygen, photodegradation, fluorescence quantum yields, triplet quantum yields and triplet life times of these complexes in DMSO and toluene. Complex 4 has higher singlet oxygen quantum yields, fluorescence quantum yields, triplet quantum yields and triplet life times than complexes 5 and 6. The effect of the solvents on the photophysical and photochemical parameters of the zinc(II) phthalocyanines (4, 5 and 6) are also reported.
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- Date Issued: 2009