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Refining predator-prey preference at the prey demographic level for cheetah and lion
Get PDFTraditional prey preference models estimate prey preference using a coarse species-specific body mass of three-quarters of the mean adult female body mass. This is widely assumed to estimate the average mass across prey populations, accounting for neonates, juveniles, sub-adults, and adults. However, this approach negates the models’ ability to predict demography-specific prey preferences, thus reducing our ability to predict the impacts of predation on prey populations. The objectives of this study were to 1) refine the prey selection models, using lion Panthera leo and cheetah Acinonyx jubatus as model species, by incorporating prey demographic classes and season and, 2) determine the influence of seasonal variability in availability of these prey demographic classes on cheetah reproduction. Lions preferentially killed adults of larger species (e.g., wildebeest, waterbuck, and zebra) irrespective of the season, as predicted by optimal foraging theory. Sub-adult, juvenile, and neonate prey were killed by lions relative to their abundance. Cheetahs preferred juvenile prey of large species, namely kudu, zebra, and wildebeest. Season influenced cheetah preference with neonates and juveniles being preferred during the wet season and adults of smaller species, and juveniles of larger species being preferred during the dry season. Thus, results support the alternative demographic class hypothesis. Furthermore, the availability of neonate and juvenile prey drives cheetah reproduction patterns with conception and cub independence coinciding with the peak availability of easy-to-catch neonates. Lactation coincided with the high availability of relatively larger juveniles to ensure that females obtain enough resources to sustain the most energetically costly reproductive phase. In addition, I suggest cheetah may be particularly vulnerable to disturbances that impact on prey reproduction (e.g., drought, fire, and flood), given their reliance on neonate and juvenile prey. My findings highlight that estimating species-level prey preference using a coarse species-specific body mass masks the level of prey use and potential preferences for the different prey demographic classes. The use of some prey species may be largely confined to juveniles by smaller predators, meaning that prey availability would vary seasonally, may influence reproductive patterns, and carrying capacity models would need to be revised in terms of the available demographic-specific prey biomass.Thesis (MSc) -- Faculty of Sciences, School of Environmental Sciences, 202
Large and multi scale mechanistic modeling of Diels-Alder reactions
Get PDFThe [4+2] cycloaddition reaction between conjugated dienes and substituted alkenes is known as the Diels-Alder (DA) reaction, in honor of two German chemists, Otto Diels and Kurt Alder, who first reported this marvelous chemical transformation. The DA reaction is one of the most popular reactions in organic chemistry, allowing for the regio- and stereospecific establishment of six-membered rings with up to four stereogenic centers. This pericyclic reaction has found many applications in areas as diverse as natural products chemistry, polymer chemistry, and agrochemistry. Over the past decades, the mechanism of the Diels-Alder (DA) reaction has been the subject of numerous studies, dealing with questions as diverse as the mechanistic pathway, the synchronicity, the use of catalysts, the effect of solvents and salts, etc. On the other hand, as an example, fullerenes (and particularly [60] fullerene) have been found to act as good dienophiles in DA reactions to the extent that many functionalized fullerenes with interesting applications are still synthesized by reacting C60 with dienes. However, despite the very abundant literature about the mechanism of the DA reaction, some pertinent questions have been still pending, including, without being restricted to, the prediction of transition state (TS) geometries and the modeling of DA reactions involving large systems, such as those of C60 fullerene. It must be emphasized that TSs are not easy to predict and the main reason is that many existing algorithms require that the search is initiated from a good starting point (guess TS), which must be very similar to the actual TS. This problem is even more difficult when many TSs are to be located as may be the case in large-scale studies. Moreover, due to the large size of the C60 molecule, the usage of accurate high-level computational methods in the investigation of its reactivity towards dienes is computationally costly, implying the need to find the best threshold between accuracy and computational cost. Therefore, the present study was carried out to contribute to solving the problems of large-scale prediction of DA transition state geometries and the multi-scale modeling of C60 fullerene DA reactions. To address the first problem (large-scale prediction of TSs), we have developed a python program named “AMADAR”, which predicts an unlimited number of DA transition states, using only the SMILES strings of the cycloadducts. AMADAR is customizable and allows for the description of intramolecular DA reactions as well as systems resulting in competing paths. In addition, The AMADAR tool contains two separate modules that perform reaction force analyses and atomic decomposition of energy derivatives from the predicted Intrinsic Reaction Coordinates (IRC) paths. The performance of AMADAR was assessed using 2000 DA cycloadducts and showed a success rate of ~ 95%. Most of the errors were due to basis set inconsistencies or convergence issues that we are still working on. Furthermore, a set of 150 IRC paths generated by the AMADAR program were analyzed to get insight into the (a)synchronicity of DA reactions. This investigation confirmed that the reaction force constant (second derivatives of the system energy with respect to the reaction coordinate) was a good indicator of synchronicity in DA reactions. A close inspection of the profile of has enabled us to propose an alternative classification of DA reactions based on their synchronicity degree, in terms of (quasi)-synchronous, moderate asynchronous, asynchronous, and likely two-steps DA reactions. Natural population analyses seemed to indicate that the global maximum of the reaction force constant could be identified with the formation of all the bonds in the reaction site. Finally, the atomic resolution of energy derivatives suggested that the mechanism of the DA reaction involves two inner elementary processes associated with the formation of each C-C bond. A striking mechanistic difference between synchronous and asynchronous DA reactions emerging from this study is that, in asynchronous reactions, the driving and retarding forces are mainly caused by the fast and slow-forming bonds (elementary process) respectively, while in the case of synchronous ones both elementary processes retard and drive the process concomitantly and equivalently. Regarding the DA reaction of C60 fullerene that was considered to illustrate the problem of multiscale modeling, we have constructed 12 ONIOM2 and 10 ONIOM3 models combining five semi-empirical methods (AM1, PM3, PM3MM, PDDG, PM6) and the LDA(SVWN) functional in conjunction with the B3LYP/6-31G(d) level. Then, their accuracy and efficiency were assessed in comparison with the pure B3LYP/6-31G(d) level considering first the DA reaction between C60 and cyclopentadiene whose experimental data are available. Further, different DFT functionals were employed in place of the B3LYP functional to describe the higher-layer of the best ONIOM partition, and the results obtained were compared to experimental data. At this step, the ONIOM2(M06-2X/6-31 G(d): SVWN/STO-3G) model, where the higher layer encompasses the diene and pyracyclene portion of C60, was found to provide the best tradeoff between accuracy and cost, with respect to experimental data. This model showed errors lower than 2.6 and 2.0 kcal/mol for the estimation of the activation and reaction enthalpies respectively. We have also demonstrated, by comparing several ONIOM2(DFT/6-31G(d): SVWN/STO-3G) models, the importance of dispersion corrections in the accurate estimation of reaction and activation energies. Finally, we have considered a set of 21 dienes, including anthracene, 1,3-butadiene, 1,3-cyclopentadiene, furan, thiophene, selenothiophene, pyrrole and their mono-cyano and hydroxyl derivatives to get insight into the DA reaction of C60 using the best ONIOM2(M06-2X/6-31 G(d): SVWN/STO-3G) model. For a given diene and its derivatives, the analysis of frontier molecular orbitals provides a consistent explanation for the substituent effect on the activation barrier. It revealed that electron-donating (withdrawing) groups such as -OH (–CN) cut down on the activation barrier of the reaction by lowering (extending) of the HOMOdiene – LUMOC60 gap and consequently enhancing (weakening) the interaction between the two reactants. Further, the decomposition of the activation energy into the strain and interaction components suggested that, for a given diene, electron-donating groups (here –OH) diminish the height of the activation barrier not only by favoring the attractive interaction between the diene and C60, but also by reducing the strain energy of the system; the opposite effect is observed for electron-withdrawing groups (here –CN). In contrast with some previous findings on typical DA reactions, we could not infer any general rule applicable to the entire dataset for the prediction of activation energies because the latter does not correlate well with either of the TS polarity, electrophilicity of the diene, or the reaction energy.Thesis (MSc) -- Faculty of Science, Chemistry, 202
A model for recommending related research papers: A natural language processing approach
Get PDFThe volume of information generated lately has led to information overload, which has impacted researchers’ decision-making capabilities. Researchers have access to a variety of digital libraries to retrieve information. Digital libraries often offer access to a number of journal articles and books. Although digital libraries have search mechanisms it still takes much time to find related research papers. The main aim of this study was to develop a model that uses machine learning techniques to recommend related research papers. The conceptual model was informed by literature on recommender systems in other domains. Furthermore, a literature survey on machine learning techniques helped to identify candidate techniques that could be used. The model comprises four phases. These phases are completed twice, the first time for learning from the data and the second time when a recommendation is sought. The four phases are: (1) identify and remove stopwords, (2) stemming the data, (3) identify the topics for the model, and (4) measuring similarity between documents. The model is implemented and demonstrated using a prototype to recommend research papers using a natural language processing approach. The prototype underwent three iterations. The first iteration focused on understanding the problem domain by exploring how recommender systems and related techniques work. The second iteration focused on pre-processing techniques, topic modeling and similarity measures of two probability distributions. The third iteration focused on refining the prototype, and documenting the lessons learned throughout the process. Practical lessons were learned while finalising the model and constructing the prototype. These practical lessons should help to identify opportunities for future research.Thesis (MIT) -- Faculty of Engineering the Built Environment and Technology, Information Technology, 202
Appropriation or appreciation: assessing cultural adoption in terms of diverse conceptions of otherness
Get PDFReciprocal, cross-cultural adoption of “symbols, artefacts, rituals, genres, and/or technologies” (Rogers 2006: 477) is an everyday phenomenon in today’s highly mediated popular culture. Increasingly, however, instances of cultural adoption are coming under the spotlight of media scrutiny, and are generating public outcry, as alleged forms of exploitative ‘cultural appropriation’. In an overly easy counter-argument it may be insisted rather that cultural adoption is a form of affirmative ‘cultural appreciation’. The question arises of how cultural theorists, as well as media practitioners and media consumers may usefully assess contentions instances of cultural adoption. How does a person decide whether an instance of cultural adoption is unacceptable ‘cultural appropriation’ or acceptable ‘cultural appreciation’? It is especially important to answer this question with regard to postcolonial societies (such as South Africa), where ingrained power imbalances make it easy for instances of cultural adoption to silence, exploit, misrepresent, or offend and in this way “exacerbate inequality and marginalization” (Matthes 2018: 1003). By contrast, affirmation of cultural identity and cultural heritage through respectful cultural adoption can play a significant role in fostering social cohesion. This study aims, firstly, to address the theoretical problem of how to assess contentious instances of cultural adoption, by contributing to the development of a systematic, but non-binary, theoretical framework, that will help cultural theorists and others to justify critical assessments regarding cultural adoption and make recommendations about whether or not they should be condoned. Secondly, it aims to test the application of this theoretical framework through the critical analysis of a selected instance of cultural adoption. The study is situated in the field of cultural studies, which falls within the broader domain of media studies. The research is cross-disciplinary in nature. A preliminary literature review supports the research hypothesis that a systematic theoretical framework for justifying critical assessments regarding cultural adoption can be developed from the complex concept of ‘Otherness’. Text-based, theoretical research will be conducted to elaborate on this proposed framework. Further, media products will be critically analysed in terms of this framework, to test and potentially modify it. No interviews will be conducted, and no ethics clearance is needed for this research.Thesis (MA) -- Faculty of Humanities, Media and Communication, 202
Foraging behaviour of the Sooty Albatross in relation to climatic variability and fisheries
No full textAs top predators, seabirds occupy the upper trophic level of marine ecosystems. They are consequently important for the maintenance of ecosystem structure and function, while also possessing characteristics which are useful for identifying climate-driven changes in oceanography at all trophic levels. This important faunal group is one of the most threatened, with climate change and fisheries bycatch mortality being the primary drivers of population declines. Understanding these threats is important for the management of threatened seabird populations. One impact of climate change and variability in climate occurs through changes in prey availability. As central place foragers, breeding seabirds have trip duration constraints due to the obligation of nest duties. This makes them particularly vulnerable to changes in prey availability within their foraging ranges. The ability to adjust foraging behaviour during environmental conditions which alter prey availability is an important attribute which can contribute to breeding success. Thus, investigating for this foraging behavioural plasticity during different breeding stages provides insights into how a species is likely to be impacted by climate change. The sooty albatross population on Marion Island was studied and displayed a degree of foraging behavioural plasticity during the five-year period of pronounced climatic variability studied. Incubating birds mainly foraged in the subtropical convergence zone (STCZ), the Sub Antarctic Front (SAF) and Subtropical Front (STF) which border it, and the region north of the STF. Brooding birds mainly used the SAF and Polar Frontal Zone (PFZ). Significantly different areas were used between years during both breeding stages. This population showed a lack of consistent habitat preferences which may offer resilience to progressive climatic variability and change. Interactions of sooty albatrosses, as well as white-chinned petrels for comparative purposes, with fisheries were also assessed. The two species were compared to shed light on possible explanations for differences in seabird-fishery interactions between the species. The impact of fisheries-related mortality (bycatch) is dependent on exposure to fishing activity and attraction to fishing boats encountered while foraging. Bycatch mortality has previously been proposed as the main cause of this sooty albatross population’s decline. Exposure and 6 attraction to fishing boats was found to be lower than that of white-chinned petrels which are bycatch prone. However, the current level of attraction exhibited by this sooty albatross population may expose a significant fraction of the population to bycatch risk due to its small population size. Additionally, all fishing boats were encountered north of the STF where non breeding individuals are now known to be distributed. Thus, the impact of fisheries on this population may mainly be mediated by more bycatch prone non-breeding individuals. Overall, the relative impact of fisheries bycatch mortality is suggested to be higher than that of climatic impacts on the sooty albatross population on Marion Island. However, this study did not incorporate dietary and demographic information which would reveal whether there are nutritional differences between years that may impact on breeding success. An integrated rather than independent assessment of foraging behavioural responses to climatic variability and fishing activity is recommended for improving our understanding of current and future conservation priorities.Thesis (MSc) -- Faculty of Science, Zoology , 202
An Antrhrological investigation of the Motherwell township community members regarding academic drop-outs
Get PDFThis research study investigated the Motherwell Township community members regarding academic drop out. The Motherwell Township is located in the city of Port Elizabeth and it is one of the largest townships in South Africa. The current outlook of South Africa’s education system has many challenges which is greatly impacted by poverty, insufficient resources and inequalities in terms of schooling, race and class. South Africa is one of the many countries with a high number of students who do not complete their university studies. This influences the young people’s future as it reduces the chances of employment. To understand the factors that contribute to academic drop out, this research study explored factors that causes female and male students to drop out. The community members provided the following reasons; lack of financial stability to sustain their academic tuition, poor performance, peer pressure, consumption of harmful substances such as alcohol and drugs, pregnancy, rape and illnesses. These factors suggested three underlying themes that influence students to remain in school namely, improvement of health facilities, better financial policies e.g. university scholarships and reduction of poverty. The objectives of this study are as follows: to investigate the causes of academic drop outs in Motherwell Township, to contribute with the anthropology of education particularly with reference to Motherwell Township in the Eastern Cape Province and to come up with recommendations with the view to address some of the challenges faced by the people who are affected.Thesis (MA) -- Faculty of Humanities, Sociology and Anthropology, 202
Evaluation of groundwater potential using geological and geophysical methods in the University of Fort Hare Alice Campus, Eastern Cape Province of South Africa
Get PDFGeological and geophysical methods were used to evaluate the groundwater potential in University of Fort Hare (Alice campus), Eastern Cape Province of South Africa. Methodologies adopted for obtaining these results included a comprehensive literature review, thin section analysis, scanning electron microscopy, Geographical Information Systems (GIS), remote sensing and geophysical investigations (magnetic survey and vertical electrical sounding). The geology of the study area belongs to the Balfour Formation, which forms part of the Beaufort Group in the Karoo Supergroup. The rocks within the study area are composed majorly of sandstone and mudstone. Lineaments were automatically extracted using the PCI Geomatica 2018 software. Fifteen samples were collected at various locations within the study area and were analyzed using the petrographic microscope while others were analyzed with the Scanning Electron Microscopic (SEM) combined with an Energy dispersive x-ray spectrometry. The results show that the rocks are fractured, porous and contained minerals such as quartz, feldspar, calcite, mica and clay minerals. The occurrence of these fractures helps to improve the groundwater storage capacity in the study area. Out of the twenty seven (27) rock samples collected in the field, ten (10) rock samples were selected for densities (dry, wet and grain densities) and porosity measurements in the laboratory. The rocks density values range from 2.5763 – 2.6978 g/cm3. The average porosities of the rocks range from 0.85 – 2.56 percent. The density of the sandstone ranges from 2.5908 – 2.6820 g/cm3 whilst the porosity range from 0.85 – 2.02 percent. The density of the mudstone ranges from 2.5763 – 2.6978 g/cm3 whilst the porosity ranges from 1.84 – 2.56 percent. About 8458 magnetic measurements were taken at about 20 m spacing along linear and non-linear paths and road. A variety of magnetic maps were generated. Several magnetic highs were observed and the linear highs were interpreted to be due to dolerite dykes whilst the broader high zones were inferred to be due to dolerite sills. These Karoo dolerites intruded the sediments at various depths and must have fractured the sediments causing them to be more porous and permeable. The depth slices of magnetic data reveal that near surface magnetic bodies occur within the depth of approximately 19 m from the surface while deep seated ones occur as deep as 31 m and maybe deeper. The knowledge of the dolerite intrusions enabled the location of drilling targets for groundwater. Electrical resistivity data were collected at 28 sites using the Schlumberger array and a maximum cable length (250 m) from the centre point which achieved a maximum depth penetration of about 70 m to 162 m. The results from 1D modelling using WINRESIST software showed that the vertical electric sounding curves are composed of HA and HK curve-types, which show four geoelectric layers. The resistivity of the first layer which is the topmost layer has values ranging from 20 - 5752 Ωm and the thickness is between 0.4 – 1.8 m. The second layer which consists of clay, mudstone and sandstone has resistivity values varying from 3 - 51 Ωm and thickness varying from 0.8 – 17.5 m. The third layer which is interpreted to be the aquiferous layer of the study area is made up majorly of sandstone with resistivity that varies from 136 – 352 Ωm and thickness range from 9.9 – 143.9 m. The fourth layer of resistivity varying from 44 to 60428 Ωm is made up of mudstone and sandstone, which are in some places intruded by dolerites. Groundwater potential is favourably high in some of the areas investigated. Furthermore, the results of the research indicated that secondary porosity is the main porosity for the reservoir rocks in the study area.Thesis (MSc) -- Faculty of Science and Agriculture, 202
Exploring the spiritual meaning of water among Amaxhosa: The study of spiritual practices in Isinuka
Get PDFThis study explores the spiritual relationship of water and uluntu lwase (people of) Port St. Johns, Eastern Cape, South Africa. Particularly the people that reside or regularly visit Isinuka sacred springs. This is done through an analysis and observations of the ritual practises performed at Isinuka sacred springs in Port St. Johns. This spring has provided sacred water used for healing, cleansing, and drinking for decades. Therefore, in this research we use the sacred water as an analysis point to understand the genesis of the ecological relationship of indigenous people and the environment. More so, this study uses the sacred water of the spring as an access point into indigenous knowledge systems (IKS) that have been passed on and maintained throughout history by the African elders. µRitual archives¶ have proved to carry indigenous knowledge systems on the history and philosophies of native regions and countries. Therefore, folktales, rituals, idioms and songs are didactic, and were intended to teach and sustain Isintu sakwa Xhosa (customs). This study uses observations ritual practises and face to face interviews to uncover the importance of nature and indigenous understanding of the environment from AmaXhosa residing in this area. The study was conducted in Port St. Johns in the rural parts of the Eastern Cape. Port St. Johns is a region of residing amaMpondo, which is an isiXhosa dialect. Therefore, amaMpondo and AmaXhosa are used in the study interchangeably. The researcher spent weeks visiting the spring daily and conducting qualitative semi-structured interviews. Observations and partaking in rituals were also used as a methodological approach to understand and capture the full experience of the sacred spring. The study uses the concept of as a medium to examine the relationship of water to spiritual ritual practises. The study literature shows a huge disjuncture between the literature written about the spring and the sociological meaning of the spring to the people that visit the spring. The results showed that the healing properties in the spring were caused by elements such as sulphur(s) and not the only the ritual practises that are performed at the spring. The study shows that, it is in the ritual practises that native Africans show their knowledge of the historical cosmological relationship between people and the environment. This is indicated in their use of sacred sites such as caves, rivers and ocean water to communicate with their ancestors. This study hopes to contribute towards a richer understanding of spirituality, ritual and archival work, for a holistic policymaking when dealing with water policies through an inclusive African indigenous perspective.Thesis (MA) -- Faculty of Humanities, School of Sociology and anthropology, 202
Exploring the role of the Department of Social Development on the integrated school health programme in the Buffalo City Municipality .
Get PDFIf one’s health is a state of wellbeing then the role of social development is key in the implementation of the Integrated School Health Programme (ISHP) as it includes treatment and prevention of psychosocial dysfunction. The purpose of the study was to explore the role of the Department of Social Development (DSD) within the ISHP in Buffalo City Municipality. DSD services are complex hence the need active collaboration to ensure delivery of multi-sectoral services. Covid-19 evidently shows the link between physical, emotional and academic success (OECD, 2020). The trauma and challenges faced by learners’ manifests through behavioral problems that social workers and counsellors can address more effectively. Social work practice aims to treat and prevent psychosocial dysfunction, thus social workers remain integral in addressing social determinants of health. The challenges in the implementation of ISHP began at policy development, moreover they were exacerbated by poor coordination and management of the ISHP. The legislative framework however affords learners the right to protective care and support. The role of social development is not limited to transportation but has been captured through psychosocial support. The study suitably employed a qualitative research design to examine how the participants make sense of the Integrated School Health Programme and to provide a comprehensive description of the complex role of the DSD in the provision of psychosocial support. 15 participants from DOH, DoE and DSD were interviewed to capture the perspective of all three (3) departments. The findings indicated how the development of the policy impacts implementation. The DSD is participating in the implementation of ISHP, however the failure of the policy to capture the role of the DSD, hinders the DSD from full participation. The study also found a lack of resourcesto support implementation and often struggle to get learners but implementation varies. Conclusively, the study recommends the need for the departments to develop a Memorandum of Understanding, Terms of reference as well as Integrated Implementation plans in an effort to support and close the gaps identified in the policy. Collaboration was found to be an effective strategy to enhance resource mobilization. Coordination and Management still need to be strengthened, including accountability.Thesis (MPA) -- University of Fort Hare, 202
An investigating of the causes of conflict in the department of employment and labour in Port Elizabeth
No full textThe public sector in South Africa accounts for a huge amount of the public service jobs and it has been learnt that there is also a considerable amount of dysfunctional conflict that affects the public sector. The main aim of this study is to investigate the causes of conflict in the public sector, with specific reference to the department of Employment and Labour, in Port Elizabeth. The research objectives were as follows; firstly, to investigate the causes of conflict or potential conflict at the department of Employment and Labour in Port Elizabeth. Secondly, the research sought to ascertain government employees’ approach to conflict and how it affects their performance (management and subordinates) with specific reference to the department of Employment and Labour, in Port Elizabeth. Thirdly, the research also sought to come up with the recommendations with the view to address conflict or what might be causing conflict at the department of Employment and Labour in Port Elizabeth. Workplace conflict was used in this study as a conceptual framework to understand conflict in the department of Employment and Labour, in Port Elizabeth. The research has followed a qualitative approach to gather data. Using a purposive selection sampling technique, 12 semi-structured interviews were conducted with employees of the department of Employment and Labour, in Port Elizabeth. Ethical considerations were adhered to throughout the course of the study. The findings of this study have revealed that lack of consultation or lack of an inclusive or participative approach in dealing with matters is regarded as the main cause of conflict within the studied organisation. The organisations lack conflict management skills. This study can be of benefit to the organisation, in that its recommendations can assist the organisation place more attention on improving its conflict management skills, which may help reduce the negative impacts of unmanaged conflicts.Thesis (MA) -- Faculty of Humanities, School of Governmental and Social Sciences, 202