An investigation of traveling ionospheric disturbances (TIDs) in the SANAE HF radar data
- Authors: Atilaw, Tsige Yared
- Date: 2022-04-07
- Subjects: Ionospheric storms Antarctica , Radar Antarctica , Range time-intensity (RTI) , South African National Antarctic Expedition (SANAE) , Super Dual Auroral Radar Network (SuperDARN)
- Language: English
- Type: Doctoral thesis , text
- Identifier: http://hdl.handle.net/10962/232377 , vital:49986 , DOI 10.21504/10962/232377
- Description: This thesis aims to study the characteristics of traveling ionospheric disturbances (TIDs) as identified in the radar data of the South African National Antarctic Expedition (SANAE) Super Dual Auroral Radar Network (SuperDARN) radar located in Antarctica. For this project, 22 TIDs were identified from visual inspection of range time-intensity (RTI) plots of backscattered power and Doppler velocity parameters of the SANAE radar between 2005âAS2015. These events were studied to determine their characteristics and driving mechanisms. Where good quality data were available, the SANAE HF radar data were supplemented by Halley radar data, which has large area of overlapping field of view (FOV) with the SANAE radar, and also by GPS TEC data. This provided a multi-instrument data analysis of some TID events. Different spectral analysis methods, namely the multitaper method (MTM), Fast Fourier transform (FFT) and the Lomb-Scargle periodogram were used to obtain spectral information of the observed waves. The advantage of using multiple windowing in MTM over the traditional windowing method was illustrated using one of the TID events. In addition, the analytic signal of the wave from the MTM method was used to estimate the instantaneous phase velocity and propagation azimuth of the wave, which was able to track the change in the characteristics of the medium-scale TID (MSTID) efficiently throughout the duration of the event. This is a clear advantage over other windowing techniques. The energy contribution by this MSTID through Joule heating was estimated over the region where spectral analysis of both SANAE and Halley data showed it to be present. The majority of the TIDs (65.4%) could be classified as MSTIDs with periods of 20–60 minutes, velocities of 50–333 ms1 and wavelengths of 129–833 km. The TID occurrence rate was high around the March equinox with 12 out of the 16 event days being during March–May. March had a particularly high number of occurrences of TIDs (46%). The majority of the TIDs observed during this month propagated northward or southeastward. In terms of prevailing geomagnetic conditions, 6 out of 16 event days were geomagnetically quiet, while 10 occurred during geomagnetic storms and substorms. During quiet conditions, TIDs could be linked to Es and polarised electric fields in 2 of these events. The other quiet time events could not be related to Es instability and polarised electric field either because their exact propagation direction could not be determined or data quality from the Es region scatter was too poor to perform spectral analysis. The storm-/substorm-related TIDs are possibly generated through Joule heating, the Lorentz force and energetic particle precipitation. , Thesis (PhD) -- Faculty of Science, Physics and Electronics, 2022
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- Date Issued: 2022-04-07
Individual decision-making and cooperation in freshwater fisheries management at the Somme River, northern France
- Authors: Khumalo, Brian
- Date: 2022-04-07
- Subjects: Fishery management France Somme River , Fisheries France Somme River , Human ecology France Somme River , Traditional ecological knowledge France Somme River , Decision making , Experimental economics , Recreation France Somme River
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/294561 , vital:57233
- Description: Are altruistic individuals more likely to cooperate when exploiting common resources? This research study asks whether or not rates of human altruistic behaviour expressed by individual recreational fishers in interpersonal contexts at the Somme River, Amiens mirror those rates of altruism expressed in collective contexts concerning local fisheries resources. In a natural resources context, altruism manifests as a willingness by fishers to incur personal cost for common-pool resource benefit. Accordingly, it is understood that altruistic behaviour reflected collectively expresses itself as cooperation. The research study takes place in Northern France with the stated objectives to: 1) observe individual fishers’ altruistic propensities in interpersonal contexts involving other fishers, 2) observe individual rates of altruistic behaviour in collective contexts involving common fisheries resources and compare with those expressed interpersonally, and 3) investigate whether or not a local (informal) management system existed in the town of Amiens to better understand if informal tenure of water space influences altruistic behaviour or not. The research design consists of two components, one quantitative and one qualitative. The former employs two economic games; a Dictators Games (DG) and a Public Good Game (PGG) in service of the first and second research objectives, and the latter employs cognitive mapping and free-listing exercises in service of the third. Here economic games stand as proxies for real-world situations involving individual (DG) and collective (PGG) decision-making whereas the exercises seek to uncover local ecological knowledge (LEK). The results found that while individual recreational fishers demonstrated lower rates of interpersonal altruism overall, in a collective setting involving local fisheries resources the rate was higher, implying a greater willingness to incur personal cost. Ecological knowledge was high among experienced fishers, yet no knowledge pertaining to parallel management and or informal rules of exclusion or resource subtraction were observed, suggesting an informal management system did not exist. The study additionally documents freshwater biodiversity, providing an index of fish species present in the river collected from the free-listing exercises, categorized into native and non-native as the latter can negatively affect trophic systems and ecosystem processes. , Thesis (MSocSci) -- Faculty of Humanities, Anthropology, 2022
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- Date Issued: 2022-04-07
Understanding trance states from the perspective of South African traditional healers - in relation to psychosis
- Authors: Masia, Ntombifuthi Thato
- Date: 2022-04-07
- Subjects: Trance , Psychoses , Altered states of consciousness , Healers South Africa , Healers South Africa Attitudes , Mental health services South Africa , Psychoses Alternative treatment , Psychoses Alternative treatment Moral and ethical aspects
- Language: English
- Type: Master's article , text
- Identifier: http://hdl.handle.net/10962/232877 , vital:50034
- Description: Studies conducted on psychosis, sleep and trance states have indicated that the phenomenon of trance occurs quite similarly to that of psychosis. Trance states (or, altered states of consciousness) are defined as mental states in which there is an alteration in the informational or representational relationships between consciousness and the world, whereby the mechanisms of consciousness have an increased tendency to produce misrepresentations like hallucinations, delusions and memory or temporal distortions. This research study aimed to contribute to the knowledge of trance states, particularly as represented by the language and social processes of traditional healers in South Africa, and as experienced by them. This knowledge is geared towards providing insight on the experience and treatment of the similarly occurring phenomenon of psychosis in clinical settings. Through a qualitative study, this research found that strategies of exploration, building recognition and familiarity, and self-monitoring are used by traditional healers to reduce the distress caused by intrusive and disruptive symptoms of trance, as well as to maintain a stable self-identity while experiencing trance states. , Thesis (MA) -- Humanities, Psychology, 2022
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- Date Issued: 2022-04-07
‘They do not understand us’: a psychosocial analysis of the everyday lived experiences of a CYCC care worker in semi-rural South Africa
- Authors: Pieters, Cinnamon-Paige
- Date: 2022-04-07
- Subjects: Child care workers South Africa Attitudes , Narrative inquiry (Research method) , Intersubjectivity , Free association (Psychology) , Child care South Africa Psychological aspects , Burn out (Psychology) South Africa
- Language: English
- Type: Article , text
- Identifier: http://hdl.handle.net/10962/294482 , vital:57225
- Description: This paper employs a psychosocial framework to analyse the everyday lived experiences of a child and youth care worker in semi-rural South Africa. The aim is to provide a new perspective of care work by drawing on narrative analysis alongside a psychoanalytic approach to qualitative research. With an emphasis on the socially constructed nature of reality, the researcher aims to elucidate the rich unconscious depths of being a care worker and the dynamics of the intersubjective reality of care work. Employing a free association narrative interview technique allows the researcher to gain understanding of the narratives that the care worker draws on in the construction of his identity as a care worker. The use of a psychosocial approach enables the researcher to pay attention to both the social context that influences the narratives that he draws on, but also the psychological ‘pay offs’ of these constructions. Most notably, the study highlights how the care worker’s identity is mediated by a defended subjectivity and argues that his failures in mentalization might stem from the way he is treated as a care worker by other professionals as a result of their mindblindness. This maintains his narrative of invisibility, and the pervasive feeling of being misunderstood as a professional in his own right. The findings are discussed in terms of their contribution to understanding some of the challenges that CYCC care workers face. , Research Article (MA) -- Faculty of Humanities, Psychology, 2022
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- Date Issued: 2022-04-07