List of Titles

Quick View

A review of marine phylogeography in southern Africa

- Teske, Peter R, von der Heyden, Sophie, McQuaid, Christopher D, Barker, Nigel P

Authors: Teske, Peter R , von der Heyden, Sophie , McQuaid, Christopher D , Barker, Nigel P
Date: 2011
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/445392 , vital:74382 , https://hdl.handle.net/10520/EJC97146
Description: The southern African marine realm is located at the transition zone between the Atlantic and Indo-Pacific biomes. Its biodiversity is particularly rich and comprises faunal and floral elements from the two major oceanic regions, as well as a large number of endemics. Within this realm, strikingly different biota occur in close geographic proximity to each other, and many of the species with distributions spanning two or more of the region's marine biogeographic provinces are divided into evolutionary units that can often only be distinguished on the basis of genetic data. In this review, we describe the state of marine phylogeography in southern Africa, that is, the study of evolutionary relationships at the species level, or amongst closely related species, in relation to the region's marine environment. We focus particularly on coastal phylogeography, where much progress has recently been made in identifying phylogeographic breaks and explaining how they originated and are maintained. We also highlight numerous shortcomings that should be addressed in the near future. These include: the limited data available for commercially important organisms, particularly offshore species; the paucity of oceanographic data for nearshore areas; a dearth of studies based on multilocus data; and the fact that studying the role of diversifying selection in speciation has been limited to physiological approaches to the exclusion of genetics. It is becoming apparent that the southern African marine realm is one of the world's most interesting environments in which to study the evolutionary processes that shape not only regional, but also global patterns of marine biodiversity.
Full Text:
Date Issued: 2011

Quick View

Life history and population dynamics of invasive common carp, Cyprinus carpio, within a large turbid African impoundment

- Winker, A Henning, Weyl, Olaf L F, Booth, Anthony J, Ellender, Bruce R

Authors: Winker, A Henning , Weyl, Olaf L F , Booth, Anthony J , Ellender, Bruce R
Date: 2011
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/124898 , vital:35708 , https://doi.10.1071/MF11054
Description: Common carp (Cyprinus carpio) is one of the world’s most widely introduced and established freshwater fishes (Casal 2006). The species is considered to be one of the eight most invasive freshwater fishes (Lowe et al. 2000) and worldwide, it accounts for most of the records of successful establishments and adverse ecological effects (Casal 2006; Kulhanek et al. 2011). This invasive success suggests that feral C. carpio is equipped with a set of adaptable life history attributes that allow it to successfully colonise a wide range of habitats (Koehn 2004; Zambrano et al. 2006; Britton et al. 2007). Where feral C. carpio occurs in high densities, it is often perceived as an invasive pest species (Sivakumaran et al. 2003; Brown and Walker 2004; Koehn 2004) because it can have severe impacts on habitat heterogeneity and biodiversity by increasing water turbidity through its bottom feeding behaviour, increasing nutrient availability, decreasing benthic and macrophyte density and diversity, altering zooplankton assemblages and decreasing endemic fish abundance (Zambrano et al. 2001; Khan 2003; Kulhanek et al. 2011). Within south-east Australia, for example, C. carpio comprises the largest proportion of the ichthyobiomass in the continent’s largest river system – the Murray–Darling Basin (Gehrke et al. 1995). As a consequence, serious concerns about its threat to endemic freshwater species (Koehn 2004) have prompted several of the most recent investigations into its life history (e.g. Sivakumaran et al. 2003; Smith and Walker 2004; Brown et al. 2005). Other potential threats posed also include competition with indigenous species and the spread of diseases and parasites (Dudgeon et al. 2006). In South Africa, for example, Asian tapeworm Bothriocephalus acheilognathi is now widely distributed in seven river systems and has infected eight novel cyprinid hosts due to the translocation of infected by C. carpio from a centralized aquaculture facility (Stadtlander et al. 2011).
Full Text:
Date Issued: 2011

Quick View

MMORPG: Towards a Sustainable Livelihood Model for Africa and Beyond

- Mostert, André M, Kaschula, Russell H

Authors: Mostert, André M , Kaschula, Russell H
Date: 2011
Language: English
Type: text , book
Identifier: http://hdl.handle.net/10962/175212 , vital:42553 , ISBN ViNOrg 2011 , https://link.springer.com/chapter/10.1007/978-3-642-31800-9_4
Description: The burgeoning worlds of massively multiplayer online role-playing games (MMORPG) coupled with increasing access to the internet is opening a new paradigmatic window for a number of disciplines. Many of these have been slow to take up the challenges associated with this emergent framework, due, in no small measure, to the perception that work and play are mutually exclusive. The dominance of this dichotomy contributed to the slow uptake of the potential for these virtual worlds to be harnessed in the fields of education and employment. This reticence was due in no small measure to the technophobia that tends to characterise the adoption of new technologies within fields that have customarily eschewed an embrace.
Full Text:
Date Issued: 2011

Quick View

Theiler’s murine encephalomyelitis virus infection induces a redistribution of heat shock proteins 70 and 90 in BHK-21 cells, and is inhibited by novobiocin and geldanamycin:

- Mutsvunguma, Lorraine Z, Moetlhoa, Boitumelo, Edkins, Adrienne L, Luke, Garry A, Blatch, Gregory L, Knox, Caroline M

Authors: Mutsvunguma, Lorraine Z , Moetlhoa, Boitumelo , Edkins, Adrienne L , Luke, Garry A , Blatch, Gregory L , Knox, Caroline M
Date: 2011
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/165085 , vital:41207 , DOI: 10.1007/s12192-011-0262-x
Description: Theiler’s murine encephalomyelitis virus (TMEV) is a positive-sense RNA virus belonging to the Cardiovirus genus in the family Picornaviridae. In addition to other host cellular factors and pathways, picornaviruses utilise heat shock proteins (Hsps) to facilitate their propagation in cells. This study investigated the localisation of Hsps 70 and 90 in TMEV-infected BHK-21 cells by indirect immunofluorescence and confocal microscopy. The effect of Hsp90 inhibitors novobiocin (Nov) and geldanamycin (GA) on the development of cytopathic effect (CPE) induced by infection was also examined. Hsp90 staining was uniformly distributed in the cytoplasm of uninfected cells but was found concentrated in the perinuclear region during late infection where it overlapped with the signal for non-structural protein 2C within the viral replication complex.
Full Text:
Date Issued: 2011

Quick View

Water chemistry and effect of evapotranspiration on chemical sedimentation on the Mkuze River floodplain, South Africa:

- Humphries, M S, Kindness, A, Ellery, William F N, Hughes, J C

Authors: Humphries, M S , Kindness, A , Ellery, William F N , Hughes, J C
Date: 2011
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/144376 , vital:38340 , https://doi.org/10.1016/j.jaridenv.2011.01.013
Description: The Mkuze Wetland System, forming part of the iSimangaliso World Heritage Site, is South Africa’s largest freshwater wetland area and is known to act as a sink for naturally occurring solutes within the landscape. The chemistry of groundwater and porewater samples, collected from two transects on the Mkuze River floodplain, was investigated to identify processes involved in the control of solute concentrations. Results show that solutes in the groundwater become increasingly concentrated under the influence of evapotranspiration, resulting in the saturation, precipitation, and accumulation of less soluble compounds.
Full Text:
Date Issued: 2011

Quick View

Adult African sharptooth catfish, Clarias gariepinus, population dynamics in a small invaded warm-temperate impoundment

- Booth, Anthony J, Traas, Graham R L, Weyl, Olaf L F

Authors: Booth, Anthony J , Traas, Graham R L , Weyl, Olaf L F
Date: 2010
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/123596 , vital:35461 , https://doi.10.3377/004.045.0208
Description: African sharptooth catfish, Clarias gariepinus (Burchell 1822), is a potamodromous species that is naturally distributed from Turkey to the Orange River, South Africa (Skelton 1993). It is omnivorous, feeding on plankton, vegetation, invertebrates, carrion and fish (de Moor & Bruton 1988) and may exhibit pack-hunting behaviour when foraging for small fish (Bruton 1979; Merron 1993). Clarias gariepinus is a large (>150 cm TL, >30 kg; Bruton 1976), long-lived (validated to at least 15 years, Weyl & Booth 2008) and fast-growing (Bruton & Allanson 1980; Quick & Bruton 1984; Richardson et al. 2009) fish that attains sexual maturity within two years of age (de Moor & Bruton 1988). It is eurythermic (80–35°C), mesohalic (0–10 ppt) and has the ability to airbreathe. These attributes predispose it to surviving in all but the most adverse of conditions and have directly contributed to its wide use as an aquaculture species. These attributes have also contributed to its ability to invade waterbodies beyond its natural range (de Moor & Bruton 1988) and after inadvertent introductions such as by escape from aquaculture facilities or through water transfer schemes, C. gariepinus has established populations in many non-native environments. Such invasions include the Philippines (Mercene 1997), Bangladesh (Arthur & Ahmed 2002), Thailand (Vidthayanon 2005), India (Bhakta & Bandyopadhyay 2007) and Brazil (Cambray 2005; Vitule et al. 2006; Rocha & Schiavetti 2007). In South Africa, C. gariepinus invaded the temperate Great Fish River catchment after the species was translocated from the Orange River through a Interbasin Water Transfer (IBWT) scheme (Laurenson et al. 1989). Potential threats include predation of and competition with indigenous species, habitat degradation, and the spread of diseases and parasites (Dudgeon et al. 2006).
Full Text:
Date Issued: 2010

Quick View

Development of a stability-indicating high performance liquid chromatographic method for the analysis of topiramate and dissolution rate testing in topiramate tablets

- Mohammadi, Ali, Rezanour, Nasrin, Ansari Dogaheh, M, Walker, Roderick B

Authors: Mohammadi, Ali , Rezanour, Nasrin , Ansari Dogaheh, M , Walker, Roderick B
Date: 2010
Language: English
Type: text , Article
Identifier: vital:6412 , http://hdl.handle.net/10962/d1006507
Description: A stability-indicating high performance liquid chromatographic(HPLC) method was developed and validated for the quantitation and dissolution determination of topiramate in tablet dosage forms. An isocratic separation was achieved using a phenyl column with a flow rate of 1 mL/min using UV detection at 264 nm. Topiramate has low UV absorbtivity and was subjected to derivatization with 9-fluorenylmethyl chloroformate (FMOC-Cl). The mobile phase for the separation consisted of acetonitrile: 50 mM sodium dihydrogen phosphate(NaH2PO4) containing 3 % v/v triethylamine (pH 2.8) in a 48:52 v/v ratio. Topiramate was subjected to oxidation, hydrolysis, photolysis and heat for the purposes of stress testing. Separation was achieved for the parent compound and all the degradation products in an overall analytical run time of approximately 15 min with the parent compound topiramate eluting at approximately 9.2 min. The method was linear over the concentration range of 1-100 μg/mL (r = 0.9996) with limits of quantitation and detection of 1 and 0.3 μg/mL, respectively.
Full Text:
Date Issued: 2010

Quick View

Estuarine use by spotted grunter Pomadasys commersonnii in a South African estuary, as determined by acoustic telemetry

- Childs, Amber-Robyn, Cowley, Paul D, Næsje, T F, Booth, Anthony J, Potts, Warren M, Thorstad, Eva B, Økland, F

Authors: Childs, Amber-Robyn , Cowley, Paul D , Næsje, T F , Booth, Anthony J , Potts, Warren M , Thorstad, Eva B , Økland, F
Date: 2010
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/124428 , vital:35612 , https://doi.org/10.2989/A JMS.2008.30.1.12.462
Description: Estuaries are important in the life history and the maintenance of the diversity of coastal fish species because of their function as nursery areas for juveniles as well as feeding grounds for adults (Cyrus 1991). The dependence of many fish species on estuaries is well documented (e.g. Wallace et al. 1984, Lenanton and Potter 1987, Blaber et al. 1989, Whitfield 1990, Hoss and Thayer 1993). Spotted grunter Pomadasys commersonnii (Haemulidae) (Lacepède 1801) is an estuarine-dependent species which spawns in the KwaZulu-Natal inshore coastal waters, between August and December (Wallace 1975b, Wallace and van der Elst 1975, Harris and Cyrus 1997, 1999). The eggs and larvae are transported southwards by the Agulhas Current, and juveniles between 20 mm and 50 mm TL recruit into the KwaZulu-Natal and south-eastern Cape estuaries (Wallace and van der Elst 1975, Whitfield 1990). Juvenile spotted grunter make use of the abundant food resources in estuaries, where they grow rapidly and remain for a period of 1–3 years (Wallace and Schleyer 1979, Day et al. 1981). Upon attaining sexual maturity (at between 300 mm and 400 mm TL), they return to the marine environment (Wallace 1975b). Some adults, however, return to estuaries to feed and to regain condition after spawning (Wallace 1975b, Whitfield 1994). The return of post-spawning fish coincides with increased catches by fishers in estuaries between July and January. These events are known as ‘grunter runs’ (Wallace 1975a, Marais and Baird 1980, Marais 1988, Pradervand and Baird 2002). It is suggested that adults spend up to several months in estuaries, before moving back to sea where they undergo gonadal development and ultimately spawn (Wallace 1975b, Wallace and van der Elst 1975). It is believed that adult fish also enter estuaries in a prespawning state to gain condition en route to their spawning grounds in KwaZulu-Natal (Webb 2002).
Full Text:
Date Issued: 2010

Quick View

Growth and longevity of Exosphaeroma hylocoetes (Isopoda) under varying conditions of salinity and temperature

- Henninger, Tony O, Froneman, P William, Booth, Anthony J, Hodgson, Alan N

Authors: Henninger, Tony O , Froneman, P William , Booth, Anthony J , Hodgson, Alan N
Date: 2010
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/446784 , vital:74560 , https://doi.org/10.1080/15627020.2010.11657253
Description: The effect of temperature (15 and 25°C) and salinity (15 and 35 practical salinity units) combinations on the growth and longevity of the South African estuarine isopod Exosphaeroma hylocoetes was investigated and data analysed using the logistic growth model. No significant differences (P = 0.43 to 0.54) were obtained for the growth rates of male and female E. hylocoetes under the suite of temperature/salinity combinations. Among the variables considered, temperature was identified as the most important in influencing the growth rates of the isopod. Elevated temperatures promoted faster initial growth in both males and females. Salinity had no significant influence on the growth rates of males and females. Males (25.77 ± 3.40 weeks) lived significantly longer (P 0.001) than females (21.52 ± 3.00 weeks), allowing males (8.08 ± 0.25 mm mean body length) to attain a significantly larger size than females (6.59 ± 0.25 mm) under experimental conditions. Females, however, attained sexual maturity (at 2.5 mm body length) 2–4 weeks earlier than males (5.5 mm in length). It is suggested that the faster growth rates at the higher temperature/salinity combinations allow the isopod to reach sexual maturity at an earlier stage than those at the lower combinations.
Full Text:
Date Issued: 2010

Quick View

Politics in the slum: a view from South Africa

- Pithouse, Richard, 1970-

Authors: Pithouse, Richard, 1970-
Date: 2010
Language: English
Type: Article
Identifier: vital:6209 , http://hdl.handle.net/10962/d1008579
Description: [From introduction]The modern state, and its civil society, have always been comfortable with workers in their allotted place – be it formed around the immediate needs of industrial production, like the migrant workers hostels in apartheid South Africa or contemporary Dubai, or an attempt at creating a haven, like the suburban home which has its roots in the gendered and raced class compromise reached in North America after the Second World War. When there has been a part of the population rendered or considered superfluous to the immediate needs of production there has been a degree of comfort with the inevitably bounded spaces into which these people have been abandoned or contained – prisons, ghettos, Bantustans etc. But both the modern state and civil society have always been acutely uncomfortable with that part of the ‘dangerous class’ - vagabonds or squatters - that are, by virtue of their occupation of space outside of state regulation, by definition out of place and threatening to domination constructed, along with other lines of force, on the ordering of space.
Full Text:
Date Issued: 2010

Quick View

Semi-submersible rigs: a vector transporting entire marine communities around the world

- Wanless, Ross M, Scott, Sue, Sauer, Warwick H H, Andrew, Timothy G, Glass, James P, Godfrey, Brian, Griffiths, Charles, Yeld, Eleanor

Authors: Wanless, Ross M , Scott, Sue , Sauer, Warwick H H , Andrew, Timothy G , Glass, James P , Godfrey, Brian , Griffiths, Charles , Yeld, Eleanor
Date: 2010
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/126920 , vital:35935 , https://doi.10.1007/s10530-009-9666-2
Description: A virtually intact subtropical reef community (14 phyla, 40 families and 62 non-native taxa) was associated with a rig under tow from Brazil that became stranded on the remote island of Tristan da Cunha. This exposes rigs as a significant vector spreading alien marine organisms, and includes the first records of free-swimming marine finfish populations becoming established after unintentional movement. With relatively trivial effort, a pre-tow clean would have obviated the need to salvage and dispose of the rig (undertaken largely to address concerns about invasive species), at a cost of *US$20 million. Our findings show that towing biofouled structures across biogeographic boundaries present unexcelled opportunities for invasion to a wide diversity of marine species. Better control and management of this vector is required urgently. Simultaneous, unintentional introductions of viable populations of multiple marine organisms are rare events, and we develop a basic framework for rapid assessment of invasion risks.
Full Text:
Date Issued: 2010

Quick View

The ambivalence of African elitehood:

- Matthews, Sally

Authors: Matthews, Sally
Date: 2010
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/142442 , vital:38080 , DOI: 10.1177/0021909609357416
Description: Recent discussions in South Africa about the role of the so-called patriotic bourgeoisie highlight the much debated question of what role elite Africans can and ought to play in the upliftment of the poor. Those supporting the notion of a patriotic bourgeoisie believe that national or racial solidarity is sufficient to allow privileged Africans to act in the interests of their poorer fellow citizens. However, a reconsideration of an older discussion of African elitehood, that of Amilcar Cabral, suggests that something more may be needed before elites can act in the interests of the poor. Cabral argues that elites need to renounce their privilege and to live and struggle alongside the poor if pro-poor societal transformation is to be achieved. While Cabral may be right that shared racial or national identity is insufficient for elite solidarity with the poor, he does not consider all the complexities that arise when elites actually try to work with and for the poor. A consideration of the experiences of a long-standing Senegalese NGO reveal some of these complexities and suggest that any attempt by African elites to engage meaningfully in the upliftment of the poor, will inevitably involve continuous and difficult negotiation between paternalism and naïve egalitarianism.
Full Text:
Date Issued: 2010

Quick View

The utility of Coleoptera in forensic investigations

- Midgley, John M, Richards, Cameron S, Villet, Martin H

Authors: Midgley, John M , Richards, Cameron S , Villet, Martin H
Date: 2010
Subjects: To be catalogued
Language: English
Type: text , book chapter
Identifier: http://hdl.handle.net/10962/442783 , vital:74033 , ISBN 978-1-4020-9684-6 , https://doi.org/10.1007/978-1-4020-9684-6_4
Description: Forensic entomology is a developing field of forensic science, so there are many avenues to investigate. These avenues include novel directions that have never been addressed, as well as more critical and rigorous research into areas which have already been explored. Most research in forensic entomology has focused on flies, and beetles (Coleoptera) have been at best under-emphasized. A good example of this is the review by Smith (1986), where 70 pages are dedicated to Diptera and only 12 to Coleoptera; this situation has changed little in the subsequent 20 years. To contextualize the neglect, throughout the world there are at least as many species of Coleoptera that may visit a particular carcass as Diptera (Braack 1986; Louw and van der Linde 1993; Bourel et al. 1999; Lopes de Carvalho et al. 2000; Pérez et al. 2005; Shea 2005; Watson and Carlton 2005a; Salazar 2006; Martinez et al. 2007). A common assumption underlying the neglect of Coleoptera is that Diptera locate corpses faster, and thus give a more accurate estimate of minimum Post Mortem Interval (PMImin). Recent observations (Midgley and Villet 2009b) have shown that Thanatophilus micans (Silphidae) can locate corpses and start breeding within 24 h of death, and thus the potential utility of estimates based on this species is equal to that of those based on flies.
Full Text:
Date Issued: 2010

Showing items 121 - 140 of 234