African wildcats on unprotected land in the Northern Cape, South Africa: potential prey and conflict status
- Authors: Stadler, Cindy
- Date: 2021-10-29
- Subjects: African wildcat South Africa Northern Cape , African wildcat Effect of human beings on South Africa Northern Cape , Predation (Biology) South Africa Northern Cape , Livestock Predators of South Africa Northern Cape , Human-animal relationships South Africa Northern Cape
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/191012 , vital:45049
- Description: The African wildcat (Felis lybica cafra) is the most common and widely distributed of all wildcats. The southern Kalahari in South Africa offers favourable conditions for African wildcats and supports high wildcat densities on protected and unprotected land. African wildcats have been reported as livestock predators on South African farms, however wildcat-livestock predation is usually reported as infrequent and to have a low financial impact on the farmer. The aim of this study was, firstly, to determine what natural prey species were available for African wildcats on unprotected land and, secondly, to determine the extent of human-wildcat conflict on unprotected land in the southern Kalahari. The frequency of occurrence of potential African wildcat prey was determined through small mammal trapping, camera trap surveys and direct observations. The results indicated that a variety of the African wildcat’s natural prey species occurred on unprotected land and that the dune and adjacent ‘street' habitats most likely supported the majority of small mammals which are preferred prey for African wildcats. The African wildcat’s human-predator conflict status was determined through interview questionnaires (n = 22) with participants who owned or managed farms in the southern Kalahari. African wildcats were perceived to occur on 100% of farms, to be common in the region, to be the top livestock predator on 68% of farms and to be responsible for 46% (n = 1542 newborn lambs) of all livestock deaths in 2020. African wildcats were, however, not viewed in the same negative light as black-backed jackals (Canis mesomelas) and caracals (Caracal caracal), who received more negativity from participants and who had the highest persecution rates in my study area. This result could potentially be explained by a combination of generationally taught hatred towards certain species and due to the perceived livestock loss (e.g. livestock size and species) caused by each predator species. It is important to research and monitor wildcats outside protected areas to obtain a deeper knowledge of wildcat behaviour, abundance, population dynamics and other aspects of their ecology. By doing this, specific conservation and management questions can be addressed and through the knowledge of the natural history of a species, conservation failures can be avoided. , Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 2021
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Modifcations to gravitational waves due to matter shells
- Authors: Naidoo, Monogaran
- Date: 2021-10-29
- Subjects: Gravitational waves , General relativity (Physics) , Einstein field equations , Cosmology , Matter shells
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/191118 , vital:45062 , 10.21504/10962/191119
- Description: As detections of gravitational waves (GWs) mount, the need to investigate various effects on the propagation of these waves from the time of emission until detection also grows. We investigate how a thin low density dust shell surrounding a gravitational wave source affects the propagation of GWs. The Bondi-Sachs (BS) formalism for the Einstein equations is used for the problem of a gravitational wave (GW) source surrounded by a spherical dust shell. Using linearised perturbation theory, we and the geometry of the regions exterior to, interior to and within the shell. We and that the dust shell causes the gravitational wave to be modified both in magnitude and phase, but without any energy being transferred to or from the dust. This finding is novel. In the context of cosmology, apart from the gravitational redshift, the effects are too small to be measurable; but the effect would be measurable if a GW event were to occur with a source surrounded by a massive shell and with the radius of the shell and the wavelength of the GWs of the same order. We extended our investigation to astrophysical scenarios such as binary black hole (BBH) mergers, binary neutron star (BNS) mergers, and core collapse supernovae (CCSNe). In these scenarios, instead of a monochromatic GW source, as we used in our initial investigation, we consider burst-like GW sources. The thin density shell approach is modified to include thick shells by considering concentric thin shells and integrating. Solutions are then found for these burst-like GW sources using Fourier transforms. We show that GW echoes that are claimed to be present in the Laser Interferometer Gravitational-Wave Observatory (LIGO) data of certain events, could not have been caused by a matter shell. We do and, however, that matter shells surrounding BBH mergers, BNS mergers, and CCSNe could make modifications of order a few percent to a GW signal. These modifications are expected to be measurable in GW data with current detectors if the event is close enough and at a detectable frequency; or in future detectors with increased frequency range and amplitude sensitivity. Substantial use is made of computer algebra in these investigations. In setting the scene for our investigations, we trace the evolution of general relativity (GR) from Einstein's postulation in 1915 to vindication of his theory with the confirmation of the existence of GWs a century later. We discuss the implications of our results to current and future considerations. Calculations of GWs, both analytical and numerical, have normally assumed their propagation from source to a detector on Earth in a vacuum spacetime, and so discounted the effect of intervening matter. As we enter an era of precision GW measurements, it becomes important to quantify any effects due to propagation of GWs through a non-vacuum spacetime Observational confirmation of the modification effect that we and in astrophysical scenarios involving black holes (BHs), neutron stars (NSs) and CCSNe, would also enhance our understanding of the details of the physics of these bodies. , Thesis (PhD) -- Faculty of Science, Mathematics (Pure and Applied), 2021
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On the Wiener index of bicyclic graphs and graphs with fixed segment sequence
- Authors: Xhanti, Sinoxolo
- Date: 2021-10-29
- Subjects: Graph theory , Chemistry Mathematics , Chemistry Graphic methods , Wiener index , Bicyclic graphs , Fixed segment sequence , Degree sequence , Circumference , Core
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/190700 , vital:45019
- Description: Wiener index is defined as the sum of the distances between all unordered pairs of vertices in a graph. The study of the Wiener index is motivated by its application in chemistry. This thesis focuses on finding extremal bicyclic graphs relative to Wiener index under various conditions such as fixed circumference (length of the longest cycle) or fixed size of the core (maximal subgraph with no degree less than 2). A segment of a graph G is either a path whose end vertices have degree 1 or at least 3 in G and all the internal vertices have degree 2 in G, or a cycle where all the vertices have degree 2 in G except possibly one. The lengths of all the segments of G form it segment sequence. We also discuss extremal graphs with given segment sequence. , Thesis (MSc) -- Faculty of Science, Mathematics, 2021
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Power in periods: a Foucauldian-feminist exploration of menstruation in an all-girls’ secondary school in South Africa
- Authors: Parkinson, Catherine Anne
- Date: 2021-10-29
- Subjects: Menstruation South Africa , Menstruation Social aspects South Africa , High school girls Health and hygiene South Africa , Communication in reproductive health South Africa , Sexual health South Africa , Sex differences (Psychology) in adolescence South Africa , Male domination (Social structure) South Africa , Feminist theory , Foucault, Michel, 1926-1984. Surveiller et punir. English , Discourse analysis
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/190930 , vital:45042
- Description: Absenteeism from school among girls due to a lack of menstrual health management (MHM) products has increasingly attracted attention from researchers and activists in recent years. Having highlighted the challenges caused by a lack of MHM products, the focus has been on the available facilities at schools to ensure MHM. Many schools in South Africa lack water, sanitation and hygiene (WASH) to ensure hygiene standards for the removal of bodily excre-ment, which further causes distress to girls needing MHM while at school. To investigate fur-ther the MHM challenges girls face, apart from access to products and WASH, this qualita-tive study purposively selected an all-girls’ school with access to good sanitation facilities. This research uses Foucauldian Discourse Analysis and Feminist Theory to explore the forms of discipline and control that girls experience at school to contain their bodily functioning and fluids, and the forms of resistance and support that girls encounter with MHM at school. I will argue that the ambivalent meanings girls acquire about menstruation at home and in soci-ety persist at school despite their own views that menstruation is normal. While MHM prod-ucts and WASH facilities need to be freely available, the problematic social response to men-struation is what needs to be addressed in order to emancipate women from the social patriar-chal power that informs their understanding that menstruation is shameful. MHM cannot only encompass products and facilities but needs to encompass a change in societal views of sex-ual and reproductive health. , Thesis (MA) -- Faculty of Humanities, Psychology, 2021
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