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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

The effect of photoperiod on some aspects of reproduction in a Southern African rodent : the pouched mouse (Saccostomus Campestris)

Gray, Janine January 2001 (has links)
The pouched mouse, Saccostomus campestris is widely distributed south of the Sahara, inhabiting both subtropical and tropical latitudes and a number of different biotic zones, where it breeds seasonally. In North temperate latitudes, reproduction in small mammals is controlled by photoperiod however this cue becomes less influential as latitude decreases towards the equator. The aim of the present study is to establish the role of photoperiod in the environmental control of reproduction in a seasonally breeding small mammal at low latitudes in a highly unpredictable environment. Spermatogenesis of domesticated and Fl-generation pouched mice was not inhibited by short daylength while decreasing daylength significantly affected the oestrous cycle of adult domesticated female pouched mice. Photoperiod had little effect on the oestrous cycle of F I-generation females while a possible inherent circannual endogenous rhythm controlled inhibition of reproduction in these females. Body mass of male and female juvenile pouched mice was consistently lower in short daylength and in juvenile female pouched mice the onset of fertility may be weight-dependent. The attainment of sexual maturity of domesticated and FIlF2-generation females was retarded but not halted in short daylength and females in long daylength reached puberty 7.8 - 10.2 days earlier. Short daylength also lengthened the interval between vaginal perforation and first oestrus. Puberty in juvenile females was age-dependent as both domesticated and FIlF2-generation males attained puberty at 50 days of age, although fewer males were fertile in long daylength than short daylength. Although litter size of pouched mice was smaller in short daylength for both domesticated and wildcaught females this was not due to a reduction in the ovulation rate. Domesticated females had significantly larger litters than wild-caught females. Male and female pouched mice have evolved different reproductive strategies as males become sexually mature at the same age irrespective of photoperiod and remain fertile throughout the year. In contrast, females tend to be more complex as juveniles delay reproductive maturity and adults become nonreproductive in short daylength. However, in the presence of a fertile male and if environmental conditions are favourable, in short daylength, females can become reproductively active within approximately 3 days. Thus, although the pouched mouse has adopted a purely opportunistic reproductive strategy, vestiges of photoresponsiveness are still present in the female. The seasonality exhibited in the wild is therefore due to the female. Pouched mice live in a highly unpredictable environment so the sole use of photoperiod to regulate reproduction would be disadvantageous.
72

A monograph of the genus Passerina L. (Thymelaeaccae)

Bredenkamp, Christina Lindith 10 October 2005 (has links)
Please read the abstract in the section 00front of this document / Thesis (PhD (Botany))--University of Pretoria, 2005. / Plant Science / unrestricted
73

Alternative methods used by small-holder farmers to control ticks and bovine dermatophilosis and the impact of a changing interface of Amblyomma ticks on dermatophilosis in Zimbabwe

Ndhkovu, Daud Nyosi January 2014 (has links)
This study was carried out to document the ethno-veterinary plants and non-plant remedies that farmers used to control dermatophilosis and ticks, and validate these in vitro and in vivo, as well as determine how the interface of Amblyomma variegatum and A. hebraeum affected the epidemiology of bovine dermatophilosis at selected small-holder areas in North-West Zimbabwe. A structured questionnaire survey was used to collect information on the control methods used by farmers for the control of bovine dermatophilosis and ticks. A total of 39 plants were used by farmers for various diseases, eleven of these plants were used for the control of dermatophilosis while three were for tick control. Across the study sites, dermatophilosis was controlled using eleven plants. Among these plants; six plants; Cissus quadrangularis, Catunaregan spinosa, Pterocarpus angolensis Carica papaya, Manihot esculenta and Blumea decurrens which were frequently used were selected for further studies. In vitro and in vivo studies were conducted to validate the efficacy of these plants. The minimum inhibitory concentration and bactericidal concentration assays were used for the in vitro validation of C. quadrangularis, C. spinosa and P. angolensis. Dermatophilus congolensis was more sensitive to P. angolensis average MIC = 0.63 mg/ml than to C. quadrangularis average MIC = iii 1.25 mg/ml and C. spinosa average MIC = 2.08 mg/ml. Cissus quadrangularis was selected for in vivo studies as this plant was the one most frequently used by farmers. Its therapeutic efficacy was compared to conventional antibiotics that farmers used to treat dermatophilosis infection. In the in vivo trials C. quadrangularis did not lead to appreciable reduction in clinical disease compared to the conventional drugs. The larval packet assay was the in vitro assay used to validate the efficacy of Carica papaya, Manihot esculenta and Blumea decurrens against larvae of A. hebraeum and Rhipicephalus appendiculatus. Manihot esculenta at 20 % w/v exhibited the highest larvicidal activity against R. appendiculatus. In the in vivo study, efficacy of the plants were investigated on naturally tick-infested cattle. Mannihot esculenta exhibited the largest tick load reduction compared to the other two plants but its performance was lower than that of conventional acaricides. The effect of A. variegatum and A. hebraeum on bovine dermatophilosis was investigated by evaluating how the presence or absence of these ticks and other herd level risk factors predicted clinical dermatophilosis and its prevalence at herd level. A structured questionnaire survey was carried out to collect data on potential risk factors. At the same time, cattle were physically examined for the presence of bovine dermatophilosis, according to a pre-defined case definition, and presence or absence of Amblyomma ticks was also recorded. The multivariable binary logistic model was developed with disease status as outcome, tick presence and infestion and herd level risk factors as predictors. Of the herds examined clinical bovine dermatophilosis was detected in 45% (84/185; 95% CI: 38.2, 52.6%) of them. Herds infested with Amblyomma variegatum were associated with higher odds (OR= 6.8; iv 95% CI: 1.71, 27.10) of clinical dermatophilosis while the association was not significant (P > 0.05) in A. hebraeum infested herds. It was concluded that management practices aimed at movement and tick control would help reduce the prevalence of clinical dermatophilosis in herds.
74

The history of the Independent Fundamental Baptist Church in Southern Africa

Blackwell, Marc Stanley 25 August 2009 (has links)
The need for a worldwide assessment of Baptist history is especially important for the many who have only a limited knowledge of this broad alliance of Christians known as Baptists. Understanding how and why Independent Baptist congregations emerged from within the larger picture makes the opening chapter important, even to other Baptists. The doctrinal elements of the Independent Baptists that overlap other Christian churches need to be explained in sufficient detail to note the differences that do exist. The numerous ecclesiastical beliefs, known as "distinctives," are matters of similarity and divergence that exist within the various Baptist groupings. To understand these seemingly minor differences is to come to appreciate the fine details that often divide. Baptist often are divided by these differences of fine detail in relation to their ecclesiastical "distinctives'; even more than some of the major doctrines that have divided other churches and denominations. This makes the task of tracing the specific history of Independent Baptists a most complex undertaking. The ability to understand Independent Baptists as fundamentalists is dependent on understanding their own definition of fundamentalism in the context of American and English conservativism. The highly charged issues related to the fundamentalism between 1880 and 1980 and the influence this period and its concerns has had on Independent Fundamental Baptists and Bible churches is rarely understood. Much of the modern South African political, ethical and religious issues seem far removed fium this church but these fundamentalists nonetheless have a perspective regarding the literal interpretation of the Bible that deserves to be heard and may well have a genuine contribution to make. The Independent Fundamental Baptist missionaries and local church leadership has a character of its own. The development of its leadership and ministry style is directly related to issues such as the literalness of their Biblical interpretation and application in pastoral areas such as preaching, teaching, discipleship and pastoral counselling. Of course there are many variations of leadership style and personality within such a loose combination of church leaders. Understanding the expansion of the Independent Fundamental Baptist and Bible churches depends on having a useful awareness of the churches and organisations that work behind the scenes, primarily in the United States, to promote this Christian movement with its strong emphasis on Biblical doctrine and distinctiveness. Learning about churches that are almost totally focused on the simplicity of the Gospel and on the pivotal role local churches should have in the Christian's inner spiritual life and public attitudes is a unique study. Understanding these loosely grouped churches and their missionary and church-planting fervour opens a perspective on Christianity general, though in my opinion, mistakenly viewed as irrelevant today. Their advance and growth raises questions for many who accept the idea that relevancy is dependent on pursuing religious emotionalism or responding to contemporary social change. The Independent Fundamental Baptist and Bible churches are moving forward while following a philosophy once fairly common among South African Christianity, but now believed to be outdated and unacceptable. The purpose of this thesis is: first, to clarify who and what the Independent Fundamental Baptist and Bible churches really are, and second, to establish their rightful place in the Southern African ''family" of Baptists. Further, by explaining their goals, problems and some of their changing perspectives their historic philosophy of missiology and ministry can be understood together with their outlook on today's society and social needs. All of this should lead to a better estimate of their future viability and their potential impact on South African religious life. / Christian Spirituality, Church History and Missiology / D.Th. (Church History)
75

Challenges of the dairy industry in Southern Africa

Louw, Johannes Michiel Adriaan 03 1900 (has links)
Thesis (MBA)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: The world population is growing rapidly and places additional pressure on the natural resources of the world. The increase in the world population leads to increasing focus on food security and the nutrition of the world population. Developed countries can only produce up to a certain level to satisfy the demand for food in the world. The additional production needs to come from countries where economic and agricultural development has been lagging. The research identified five major drivers of the future growth of agriculture. These drivers of future growth create opportunities for countries in Africa and help to address the development challenges for their different agricultural sub-sectors. The dairy industry in Southern Africa can play a significant role in addressing food security and nutritional needs of the growing population. Large numbers of livestock are present in Southern Africa because the landscape is lending itself to livestock farming and cultural believes see livestock as wealth in the hands of the owner. There are however serious challenges to address in order to achieve sustainable growth in the dairy industry in Southern Africa. The focus of the report is on the identification of the challenges in the dairy industry in Southern Africa, thus helping with the formulation of a growth strategy and business model. The report used a qualitative method of literature study to determine the challenges faced by the dairy industry in three Southern African countries, i.e. South Africa, Tanzania and Zambia. The contrasts between these countries are significant, but there are also many common elements and challenges. From this range of factors a set of key “challenges for action” has been derived, which are put forward as a basis for public and private sector efforts to strengthen growth in the sector. The list of challenges also assisted in the proposal of a business model to address part of the challenges of development in the dairy industry.
76

Modelling present and future climates over Southern Africa.

Joubert, Alec Michael January 1997 (has links)
Thesis submitted to the Faculty of Science, Department of Geography and Environmental Studies, University of the Witwatersrand, Johannesburg, in fulfillment of the requirements for the Degree of Doctor of Philosophy / The representation of contemporary southern African climate by a wide range of general circulation models used in climate studies is evaluated. In addition, projections of regional climate change by the models are interpreted in terms of their present climate performance. Projections of regional climate change by two different types of climate models are considered. First, projections of the equilibrium response to an instantaneous doubling of atmospheric carbon dioxide using atmospheric models linked to simple mixed-layer oceans are assessed. Second, projections of the transient response to gradually-increasing anthropogenic forcing by fully-coupled ocean-atmosphere general circulation models are considered. All of the mixed-layer models considered have been developed since 1990 and are more recent and generally higher-resolution versions of the models considered previously for southern Africa. The improved resolution and model physics result in a general improvement in the representation of several features of circulation around southern Africa. Specifically, these include the meridional pressure gradient, the zonal wind profile, the intensity and seasonal location of the circumpolar trough and the subtropical anticyclones, as well as planetary wave structure at 500 hPa. Atmospheric models forced by observed sea-surface temperatures simulate the large-scale circulation adjustments around southern Africa known to accompany periods of above- and below-average rainfall over the subcontinent. Fully-coupled models simulate the observed features of intra- and intra- annual variability in mean sea-level pressure, although the simulated variability is weaker than observed. Summer rainfall totals throughout southern Africa are overestimated by all of the models, although the pattern of rainfall seasonality over the subcontinent as a whole is well-reproduced. The inclusion of sulphate aerosols in addition to greenhouse gases does not result in a statistically significant improvement in the simulation of contemporary temperature variability over southern Africa. Warming projected by fully-coupled models is smaller than projections by mixed-layer models due to the fact that the transient response of the fully-coupled system and not an equilibrium response of an atmospheric model linked to a mixed-layer ocean is simulated. The inclusion of sulphate aerosols results in a reduction in the magnitude and rate of warming over southern Africa. Projected changes in the diurnal temperature range are seasonally-dependent, with increases in summer and autumn and decreases in winter. Simulated changes in mean sea-level pressure are small but similar in magnitude to observed anomalies associated with extended wet and dry spells over the subcontinent. No change in rainfall seasonality over southern Africa is expected. Nonetheless, little confidence exists in projected changes in total rainfall. While both types of model simulate a 10-15% decrease in summer rainfall on average, projected changes are smaller than the simulation errors and little inter-model consensus in terms of the sign of projected changes exists. No change in the location or intensity of anticyclonic circulation and divergence at 700 hPa in winter is expected. While fully-coupled models provide a more comprehensive treatment of the global climate system and the process of climate change, there is no evidence to conclude that current fully-coupled models should be used to the exclusion of mixed-layer models when developing regional climate change scenarios for southern Africa. / Andrew Chakane 2018
77

Game viewing potential in a multi-use conservation area: a case study of the Great Limpopo Transfrontier Park, Southern Africa

Pride, Roxanne S 04 February 2015 (has links)
A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of requirements for the degree of Master of Science. / Three key objectives of transfrontier conservation are biodiversity conservation, local economic development and the promotion of peace and cooperation across international borders (Ramutsindela, 2004). Transfrontier Conservation Areas (TFCA’s) may incorporate a variety of conservation land uses, and comprise of both consumptive and non-consumptive uses of wildlife (Hanks, 2003). It is critical that this mosaic of land uses is well managed and integrated in order to meet the conservation and socio-economic goals of TFCA’s. One challenge is that different conservation land use areas may have varying effects on wildlife. This study aims to further our understanding of these effects in the Great Limpopo Transfrontier Park of South Africa and Mozambique. The research uses the behavioural responses of wildlife as a way of determining the tolerance of wildlife to potentially disturbing activities. Four different conservation land use areas, namely trophy hunting, communal land, photographic tourism and exclusive photographic tourism were studied and compared in and around the Great Limpopo Transfrontier Park, southern Africa. The aim of this study was to firstly establish the diversity of mammals and the frequency of mammal sightings within each conservation land use area, and secondly, assess the response behaviour of five mammal species to an approaching vehicle. K-means cluster analysis was used on both the mammal sightings data and the response behaviour data in order to determine key influencing variables. Throughout the study period, the mammal diversity and frequency of mammal sightings were the highest in the private ecotourism concession, followed by the national park, and then the trophy hunting reserve and lastly communal land. The behavioural responses displayed by the five study mammals (African elephant, African buffalo, impala, chacma baboon and Burchell’s zebra) also varied considerably between the four conservation land use areas. The lowest response indexes and least number of flight responses occurred in the national park, followed by the private ecotourism concession, and conversely, a higher average initial response index and a greater occurrence of flight responses occurring in the trophy hunting reserve and communal land. According to the findings from the cluster analyses, the type of conservation land use impacts on the sighting potential and sighting quality of mammals, but so do iii topographical differences and seasons. These results can help in the management of each conservation land use area on its own and as an integrated part of a TFCA.
78

Labour movements and challenges to liberation movement hegemony: considerations on South Africa in light of the Zimbabwe and Zambia experience

Ntshangase, Ntokozo Dumsani 28 January 2016 (has links)
A research report submitted to the Political Studies Department, Faculty of Humanities of the University of the Witwatersrand, in partial fulfilment of the requirements for the Masters of Arts (MA) in Political Studies. March 2015 / Trade unions have always been part of the liberation struggle in Southern Africa, whether as a civil society formation mobilizing for better wages and improved working conditions on the shop floor, or in alliance with political formations in a bid to transform society and introduce regime change. In most cases, especially in South Africa, it was the unions that continued the struggle even after political parties were banned. It was also through the mobilization strength and resources of the unions that political parties (National Liberation Movement) emerged as formidable and hegemonic forces in Zambia, Zimbabwe and South Africa. Thus, the paper argues that, in part, UNIP (and later MMD), ZANU-PF and the ANC owe their political ascendancy to the mass mobilization by the trade unions. Trade unions have often had to resist subordination by the liberation movements. The paper suggests that; the fight for independent and worker-centered trade unions, and the unilateral implementation of structural adjustment programmes, were central to the conflict between trade unions and liberation movements. These are seen as factors that undermined the dominance of National Liberation Movements hegemony. The paper argues that; the contemporary union/party relations in South Africa show similar trajectories to those in Zambia and Zimbabwe. While the literature is explicit on how UNIP and ZANU-PF lost their ideological dominance and hegemony, the continued dominance of the ANC remains an object of ongoing debate.
79

An historical evaluation of the Lutheran medical mission services in Southern Africa with special emphasis on four hospitals : 1930s-1978.

Ntsimane, Radikobo Phillip. January 2012 (has links)
The purpose of this thesis is to show through a chain of events how the Lutheran Mission societies in their quest to provide health care through biomedicine to indigenous people in Southern Africa ended up co-operating with the South African government in the implementation of the policy of apartheid. The question that this thesis will thus seek to answer is the following: If foreign missionaries were motivated to the extent that they left their homes in Europe and North America, why did they allow their hospitals to be subjected to government takeovers without offering much by the way of resistance? Biomedicine was not introduced to supplement the existing traditional health systems but to replace them. Black people had ways and means to attend to their sick through traditional health systems such as izinyanga, izangoma, and izanusi among the Zulu, and dingaka and didupe among the Sotho-Tswana. In Southern Africa, the missionaries saw suffering and great need, and worked as lay medical practitioners to alleviate health problems long before apartheid was formally introduced after the National Party came to power in 1948. Subsequently, they worked with trained medical missionary nurses and doctors. The Lutheran missionaries saw biomedicine as being not far-removed from advancing their mission work of converting the indigenous people to Christianity. In their provision of basic biomedicine from small structures, the Lutheran missionaries developed their health centres into hospitals by means of assistance from home societies before apartheid became the policy of the government. Financial assistance was also received from the South African government especially in the 1960s to combat the tuberculosis epidemic. However dedicated the missionaries were, they were condemned to see their influence gradually reduced because they were forced to rely on government subsidies in the running of the hospitals. In the 1970s, the apartheid government nationalized Lutheran and other mission hospitals. The hospitals were taken over and handed to the newly-established homelands and self-governing states to run. Under this new management, the mission hospitals’ quality of service was compromised. The question is: why did the Lutheran missions allow their hospitals to be nationalized? Overall, one can see that the Lutheran missions were influenced by race when they excluded black people from participating in the running of the mission hospitals, despite Blacks having taken over the running of the former mission churches since the 1960s. In Botswana, nationalization occurred differently. There was no total take-over of mission hospitals and the attendant exodus of white medical missionaries. From the time of independence in 1966, the Botswana government decided to work with mission societies in health care. The government formulated health policies and provided part of the financial needs of the hospitals, while the mission societies provided personnel and ran the hospitals. For example, the Bamalete Lutheran Hospital (BLH) in Ramotswa continues to be run by the Hermannsburg Mission Society. The national Lutheran Church played an important role in the hospital as the Church was part of the governing board. This thesis has attempted to show that, while the Lutheran missionaries were motivated to develop a health care system for the indigenous people through the introduction of biomedicine and the building of hospitals, they were so dependent on the assistance of the apartheid government, especially in the 1960s and the 1970s, that they could not see that their collaboration with the government in the nationalization of mission hospitals was in fact a collaboration with apartheid. Some individual mission doctors and nurses, especially in the Charles Johnson Memorial Hospital in Nquthu, resisted the nationalization programme, but not the Lutherans. These were paralysed in the face of the pseudo-nationalization programme of the apartheid regime. The interpretation of the Lutheran doctrine of the ‘Two Kingdoms’, which dissuades Christians from interfering in the sphere of secular governance, may have had bearing on their reluctance to challenge the apartheid regime to provide better health care. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.
80

Effects of management intervention on elephant behaviour in small, enclosed populations.

Druce, Heleen Coba. 25 November 2013 (has links)
The continual increase in elephant numbers across southern Africa raises concern, though the interventions to manage these populations are more contentious. Within small, enclosed reserves active management is necessary to limit elephant impact. Various management tools exist with which to control fluctuations in elephant population numbers or density and simulate natural large stochastic events to control population growth. During this study, undertaken in the Munyawana Conservancy, KwaZulu-Natal, and Pilanesberg National Park, North West Province, South Africa, several management options were implemented. In order to lower the population numbers, family groups were translocated from the Munyawana Conservancy to other reserves, while to reduce population growth rate an immunocontraception was implemented. Both conservation areas introduced older bulls to normalise the bull population age structure, and expanded the conservation area by inclusion of new land to reduce population density. The influence of these management interventions on the elephant population were measured by their social, behavioural, spatial and movement responses. The older bull introduction was successful as bulls set up exclusive bull areas. There was a quick, subtle affect on the bull groups' size immediately after the older bull introduction, while there was no immediate change within the resident bulls' musth behaviour or duration. During area expansion, elephants appeared to perceive the new unexplored area as a threat although this threat became reduced through time as they became more familiar with it. The spatial scale of response was relatively small, while the temporal scale of response was relatively large. Rotational immunocontraception was shown to be a successful tool to alter herd structure by aging the population and maintaining a low population growth rate. The process of immunocontraception darting had no significant effect on herd associations and movement rates, accordingly the duration of the disruption effects were short lived. During multi-management interventions, no differences were found within the elephant social grouping. Management interventions may pose unforeseen social risks and different populations may respond differently to management induced stress. Therefore, interventions need to be considered for each elephant population which will achieve the conservation area's objectives with the most effective outcome, but with lowest holistic impact. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2012.

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