M.A. / It is now well known that HIV/AIDS-sufferers face profound psychological, psychiatric and neurological sequelae as the disease progresses. However, studies indicate that women diagnosed with HIV-infection are twice more likely to be depressed, to suffer from PTSD and other psychiatric morbidity than men. Yet very few studies have attempted to investigate the role that gender plays in reacting to the illness. Finding out that one is HIV-infected is one of the most significant discoveries. This is due to the fact that in receiving an HIV-positive diagnosis individuals are exposed to news of prodigious personal consequence. And yet very few studies have focused on how the impact of finding out that one is HIV-positive may affect their adjustment to the illness. Moreover, how men and women are likely to react to such news. It is against this background that the current study was conducted. The aim of the current study was to compare post traumatic symptoms in men and women upon hearing news of their HIV-positive status and to investigate to what extent such reactions may be similar or different and to further assess how their reactions are likely to affect disease progression and adjustment. A total of one hundred participants (38 Male, 63 female) diagnosed with HIV/AIDS participated in the study. These men and women were obtained from support groups in the Gauteng region. The Impact of Event Scale-Revised and Mental Adjustment to HIV-Scale questionnaires were used to collect data over a period of a month. A large majority of 60.2% of the total sample (n = 87) reported experiencing feelings of shock upon hearing about their HIV-positive status, 66.0% of the total sample (n = 94) of those who responded to this item reported trying to remove the issue from their mind. A further 59.6% of the total sample of (n = 94) indicated feeling as though news about their HIV-positive status were not real suggesting that the incident was traumatic. There were no significant gender differences in how both men and women reacted to news of their HIV-positive diagnosis. However, significant differences were found in relation to adjustment. Men were found to be more likely to have more Fighting Spirit which is indicative of adaptive adjustment as compared to women. Women on the other hand were found to be more likely to be Hopeless which is indicative of maladaptive coping.

Le vieillissement amoindri de façon régulière les capacités physiques, sensorielles et parfois cognitives des individus. Le vieillissement du corps transforme également l'image offerte à autrui et à soi-même. La perception que la personne âgée a alors d’elle-même est une question qui n’est pas sans conséquence. La perception réaliste de ses capacités physiques semble nécessaire dans la réalisation d’actes moteurs alors que la perception optimiste de soi et de l’environnement semble nécessaire au maintien du moral. Notre objectif est d’étudier de façon relativement globale la perception de soi chez la personne âgée. Pour cela, nous étudions les perceptions qu’ont les personnes âgées a de leurs propres capacités dans la réalisation d’actes moteurs (posturabilité sur pente, enjambement d’obstacle), la perception qu’elles ont d’elles-mêmes par la réalisation de questionnaires d’auto-évaluation, en particulier la perception qu’elles ont de leur âge. Nous examinons également les perceptions qu’elles ont d’autrui, en particulier celles qu’elles ont d’autres personnes âgées. L’objectif est d’étudier les impacts positifs et négatifs sur leur santé des perceptions correctes ou erronées des séniors. Nos deux premières études ont mis en évidence l’existence d’un biais de surestimation de capacités posturales chez les participants âgés, qui pourrait être en lien avec une vision positive d’eux-mêmes. Ensuite nos recherches de sont intéressées à l’existence de cette surestimation des capacités motrices chez les personnes âgées présentant une détérioration cognitive (Maladie d’Alzheimer à un stade débutant). Dans une seconde partie, nos recherches se sont tournées vers l’estimation que les personnes âgées ont d’elles mêmes, en étudiant en particulier l’auto-estimation et l’hétéro-estimation de l’âge. Nos études ont montré que les personnes âgées adoptaient en général une vision optimiste d’elles-mêmes et de leurs capacités motrices ne correspondant pas à la réalité. Cette vision optimiste, bien que permettant de maintenir un bon moral peut être liée à la mise en danger sur le plan moteur. / Elderly steadily diminished physical, sensory and sometimes cognitive individuals abilities. The aging body also converts the image presented to others and to oneself. The perception that the elderly person then herself is a question which is not inconsequential. Realistic perception of physical seems necessary in motor actions while the optimistic perception of self and the environment seems necessary to maintain morale.Our goal is to study a relatively comprehensive self-perception in the elderly. For this, we study the perceptions of older people has their own abilities in performing motor acts (posturability on slope, crossing over an obstacle), their perceptions of themselves by achieving of self-assessment questionnaires, particularly their perceptions of their age. We also examine the perceptions they have of others, especially those that have other seniors. The objective is to study the positive and negative impacts on their health perceptions of older correct or incorrect. Our first two studies showed the existence of a bias of overestimating postural abilities among older participants, which could be related to a positive vision of themselves. Then our research is concerned with the existence of this overestimation of motor skills in older people with cognitive impairment (Alzheimer's disease at a beginning stage). In the second part, our research turned to the estimate that seniors have of themselves, especially in student self-assessment and hetero-age estimation.Our studies showed that older people usually adopted an optimistic view of themselves and their motor skills do not match reality. This optimistic view, although to maintain morale may be related to the endangerment on the motor.

<p>The relationship between positive urgency, a personality trait reflecting rash action during extreme positive emotional states, and risk-taking has previously been experimentally examined. However, how positive urgency is related to risk-taking while under the acute influence of alcohol has not been examined. The overarching goal of this dissertation was to generate behavioral evidence concerning how the interaction between positive urgency and alcohol consumption influences risk-taking via changes in emotional arousal. In this study, 59 community-dwelling adults (mean age = 29.45 (SD = 10.96), 32.2% women, 78% White) completed mood induction procedures (positive or neutral) while consuming a beverage (alcohol or placebo) and then completed the Balloon Analogue Risk Task (BART) as a measure of risk-taking. The positive mood induction was effective in inducing high arousal positive emotions. Overall, study hypotheses were not supported; however, because of low power, effect sizes and patterns of relationship are reported. The relationship between positive urgency and risk-taking was positive and small in the positive mood condition but negative and small in the neutral mood condition. The alcohol group and the placebo group showed similar patterns of risk-taking that are positive and small. Finally, the relationship between positive urgency changes in emotional arousal was positive and small only in the positive/alcohol condition; however, there was no relationship between changes in emotional arousal and risk-taking. These findings suggest that, while changes in emotional arousal may result from a combination of positive urgency and alcohol consumption, it may not be a focal mechanism that explains the relationship between positive urgency and risk-taking. Further, positive urgency is a risk factor whether or not alcohol consumption is present. Although the small sample size limited the power to test the hypotheses, the effect size estimates obtained in this study provide preliminary data for a more properly powered future study. The pattern of findings suggests the viability of further developing the current positive mood induction to establish a lab-based paradigm for positive urgency and the use of a different experimental risk-taking task to examine positive emotion-based risk-taking.</p>

A thesis submitted to the Faculty of Science, University of the Witwatersrand, in fulfilment of the requirements for the degree of Doctor of Philosophy. Johannesburg, 2013 / Pain is one of the most frequent and debilitating symptoms in human immunodeficiency virus (HIV) infected individuals. With Southern Africa being the region with the highest population of HIV-infected individuals, I set out to determine whether the pain intensity, prevalence and management strategies that have been reported in other, non-African, countries are similar to that in South African patients. South Africa has eleven official languages, with nine of those being native languages. Also, there is a high level of illiterate people in the country, thus, for better assessment of the pain I translated the Wisconsin Brief Pain Questionnaire into five frequently spoken local languages. Using the translated questionnaires I investigated the prevalence, intensity and management of pain in ambulatory HIV-positive outpatients attending a metropolitan (n = 396) or rural (n = 125) clinic. I also assessed whether this pain changes over time in a subset of 92 metropolitan patients. Seventy-two percent of rural participants and 56% of metropolitan participants had pain at the time of the interview, and this pain was moderate to severe in intensity in 60% of affected rural participants and 59% of affected metropolitan participants. In the rural cohort, use of antiretroviral therapy was independently associated with the reduced risk of pain [prevalence ratio (95% CI): 0.7 (0.5-0.9)] while in the metropolitan cohort increasing age was weakly, but independently associated with having pain [prevalence ratio (95% CI): 1.01 (1.005-1.012)]. Pharmacological management of pain was poor, with 29% of rural participants and 55% of metropolitan participants with pain not receiving any treatment. Of those receiving treatment, no participants were receiving strong opioids, and only 3% of metropolitan participants were receiving a weak opioid. On a positive side, the pain that South African HIV-infected individuals endure decreases over time. Seventy-eight patients out of the subsample cohort consisting of 92 patients reported pain at the time of the first interview. Of the 78 patients who were in pain at visit 1, 48 were still in pain six months later with 36 of those not prescribed any form of analgesics. Thus I found a decrease in moderate and severe intensity pain to mild and moderate pain, respectively, from visit 1 to visit 2. Of the 78 patients that were in pain at visit 1, only 5% received some form of analgesic therapy. Forty-eight of the 78 patients were still in pain six months later, and of those, 25% were being prescribed some form of analgesics at visit 2. There were no changes in the pain-related interference over a six month period in patients who were in pain at visit 1 and visit 2. Therefore, as it has been reported previously for other developed and developing countries, pain in HIV-positive South Africans is common and is under-treated. Also, there are decreases in the pain intensity, pain prevalence, the number of pain sites over a period of six months. These decreases were evident in patients who were on HAART for the duration of six months as compared to those who were not on HAART for six month.

This article reports on a study investigating the effectiveness of positive psychology interventions (PPIs) in an Intensive English Program (IEP) for non-matriculated university students. Interventions based on the PERMA model for wellbeing (positive emotion, engagement, relationships, meaning, and accomplishment) were implemented through weekly 65-minute lessons and short daily activities. Each lesson introduced an aspect of the PERMA model such as positive emotion or achievement. Along with this focused instruction, students concurrently engaged in language learning activities. Teachers also provided short daily activities for reinforcement throughout the week. Six classes received these interventions, while three classes served as a control group and did not receive any treatment. Students' wellbeing, anxiety, and depression were measured pre-, mid-, and post-semester. Language proficiency was also measured pre- and post-semester and compared with the control group. Qualitative data, which were collected through questionnaires and semi-structured interviews, were analyzed following an iterative (constant comparative) method where open coding occurred first, followed by axial coding and selective coding (Glaser and Strauss 2017). This facilitated an understanding of patterns indicative of how the PPIs might have affected student engagement and enjoyment. The quantitative analysis did not reveal any significant gains in well-being or any reductions in anxiety or depression. Despite spending 25% of instruction time on PPIs, there were no statistically significant differences in language proficiency gains compared to the control group meaning that the time taken from teaching language did not in any way reduce linguistic gains. However, the qualitative data do suggest a positive impact from the PPIs. Thus, the results of this study confirmed the findings of Seligman et al. (2009) and Gush and Greeff (2018) that PPIs can be implemented without detracting from language instruction and although gains were not statistically significant, qualitative data showed that the participants felt more positive as a result of the interventions.

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Time-delay dynamical systems are used to model many real-world engineering systems, where the future evolution of a system depends not only on current states but also on the history of states. For this reason, the study of stability and control of time-delay systems is of theoretical and practical importance. In this thesis, we develop several stability analysis frameworks for dynamical systems in the presence of communication and computation time-delays, and apply our results to different challenging engineering problems. The thesis first considers delay-independent stability of positive monotone systems. We show that the asymptotic stability of positive monotone systems whose vector fields are homogeneous is independent of the magnitude and variation of time-varying delays. We present explicit expressions that allow us to give explicit estimates of the decay rate for various classes of time-varying delays. For positive linear systems, we demonstrate that the best decay rate that our results guarantee can be found via convex optimization. We also derive a set of necessary and sufficient conditions for asymptotic stability of general positive monotone (not necessarily homogeneous) systems with time-delays. As an application of our theoretical results, we discuss delay-independent stability of continuous-time power control algorithms in wireless networks. The thesis continues by studying the convergence of asynchronous fixed-point iterations involving maximum norm pseudo-contractions. We present a powerful approach for characterizing the rate of convergence of totally asynchronous iterations, where both the update intervals and communication delays may grow unbounded. When specialized to partially asynchronous iterations (where the update intervals and communication delays have a fixed upper bound), or to particular classes of unbounded delays and update intervals, our approach allows to quantify how the degree of asynchronism affects the convergence rate. In addition, we use our results to analyze the impact of asynchrony on the convergence rate of discrete-time power control algorithms in wireless networks. The thesis finally proposes an asynchronous parallel algorithm that exploits multiple processors to solve regularized stochastic optimization problems with smooth loss functions. The algorithm allows the processors to work at different rates, perform computations independently of each other, and update global decision variables using out-of-date gradients. We characterize the iteration complexity and the convergence rate of the proposed algorithm, and show that these compare favourably with the state of the art. Furthermore, we demonstrate that the impact of asynchrony on the convergence rate of the algorithm is asymptotically negligible, and a near-linear speedup in the number of processors can be expected. / Tidsfördröjningar uppstår ofta i tekniska system: det tar tid för två ämnen attblandas, det tar tid för en vätska att rinna från ett kärl till ett annat, och det tar tid att överföra information mellan delsystem. Dessa tidsfördröjningar lederofta till försämrad systemprestanda och ibland även till instabilitet. Det är därförviktigt att utveckla teori och ingenjörsmetodik som gör det möjligt att bedöma hur tidsfördröjningar påverkar dynamiska system. I den här avhandlingen presenteras flera bidrag till detta forskningsområde. Fokusligger på att karaktärisera hur tidsfördröjningar påverkar konvergenshastigheten hos olinjära dynamiska system. I kapitel 3 och 4 behandlar vi olinjära system varstillstånd alltid är positiva. Vi visar att stabiliteten av dessa positiva system är oberoende av tidsfördröjningar och karaktäriserar hur konvergenshastigheten hos olinjära positiva system beror på tidsfördröjningarnas storlek. I kapitel 5 betraktar vi iterationer som är kontraktionsavbildningar, och analyserar hur deras konvergens påverkas av begränsade och obegränsade tidsfördröjningar. I avhandlingens sistakapitel föreslår vi en asynkron algoritm för stokastisk optimering vars asymptotiska konvergenshastighet är oberoende av tidsfördröjningar i beräkningar och i kommunikation mellan beräkningselement. / <p>QC 20151204</p>

published_or_final_version / Clinical Psychology / Master / Master of Social Sciences

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