Believe in yourself(ie): a study of young, ordinary, South African women who share selfies on Instagram

A dissertation in fulfilment for Master of Arts in Media Studies Faculty of Humanities School of Language, Literature and Media Studies (SLLM) University of the Witwatersrand 2016This research study essentially sets out to explore the practices of young, ordinary, South African women who take and post selfies on social media platforms, like Instagram. The general commentary surrounding selfies is typically negative, and tends to frame the selfietaker as a narcissistic, self-absorbed individual. Therefore, this study is interested in understanding what this very particular smartphone-enabled photographic technique means to this group of women, and in doing so, aims to determine whether or not there are underlying significances to such practices. This research study adopts a vast framework of literature in order to conceptualize and contextualize selfies in contemporary culture, by drawing on the rich history of self-portraiture and snapshots as well as concepts of mediation and the representation of the self online; in addition to describing the role that mobile technologies and social media platforms have played in contributing to cementing selfies as a cultural hallmark in today’s society. This study is additionally grounded upon three dominant theoretical themes, namely: narcissism, self-exploration, and self-regulation; and Christopher Lasch, Michel Foucault, Angela McRobbie and Rosalind Gill’s theoretical contributions are predominantly referred to in an attempt to explain such principles adequately. Through the responses that were yielded by interviewing 14 young, ordinary, South African women, this research study essentially established that the practices of selfie-taking do in fact play a significant role in the lives of these young women, from empowering them and teaching them to learn to love and accept themselves again, to inspiring personal growth, capturing special moments and memories, and allowing them to feel accepted and as though they belong and have a fixed placed in society. Therefore, this study argues that selfies are not necessarily only about narcissism and self-obsession, but rather more about the notion of self-love and acceptance (for this group of participants at least).MT201

Bacterial Pathogens Survival Strategies – The Haem Biosynthesis Pathway in Campylobacter jejuni

Campylobacter jejuni is one of the most common foodborne pathogens responsible for the majority of the worldwide diarrhoeal infections, causing illness to more than 137 million people every year according with World Health Organization. Despite its widespread and persistence, the essential molecular mechanisms for C. jejuni successful development and infection of the host are still poorly understood. This is the case of haem homeostasis, which is an essential process to bacterial development and plays a very important role during the infection process. Haem is an iron-containing porphyrin that is abundantly present in all life domains and acts as a prosthetic group for a diverse group of proteins. Haem can be either endogenously synthesised or acquired from the host. This work aims to identify and characterise C. jejuni’s haem biosynthesis pathway to better understand the role of haem biosynthesis in C. jejuni’s pathogenicity. In this work, I cloned the putative genes constituting the haem biosynthetic pathway of C. jejuni in plasmids designed for E. coli overexpression. To analyse the activity of each of the enzymes of the pathway, I complemented E. coli’s haem biosynthesis mutants with C. jejuni’s enzymes. Our results showed that C. jejuni’s genome encodes for a complete Protoporphyrin Dependent Pathway (PPD). It was further confirmed that UroD and PpfC enzymes possessed uroporphyrinogen decarboxylase and protoporphyrin ferrochelatase activities, respectively. Overall, our results strongly suggest that C. jejuni encode for a full functional PPD haem biosynthesis pathway. Further work should aim at the study of the role of these proteins in C. jejuni’s infection development

Multi-depot rural postman problems

The final publication is available at Springer via http://dx.doi.org/10.1007/s11750-016-0434-zThis paper studies multi-depot rural postman problems on an undirected graph. These problems extend the well-known undirected rural postman problem to the case where there are several depots instead of just one. Linear integer programming formulations that only use binary variables are proposed for the problem that minimizes the overall routing costs and for the model that minimizes the length of the longest route. An exact branch-and-cut algorithm is presented for each considered model, where violated constraints of both types are separated in polynomial time. Despite the difficulty of the problems, the numerical results from a series of computational experiments with various types of instances illustrate a quite good behavior of the algorithms. When the overall routing costs are minimized, over 43 % of the instances were optimally solved at the root node, and 95 % were solved at termination, most of them with a small additional computational effort. When the length of the longest route is minimized, over 25 % of the instances were optimally solved at the root node, and 99 % were solved at termination.Peer ReviewedPostprint (author's final draft

Exact solution of several families of location-arc routing problems

We model and solve several families of location-arc routing problems on an undirected graph. These problems extend the multidepot rural postman problem to the case where the depots are not fixed. The aim is to select the facility locations and to construct a set of routes traversing each required edge of the graph, where each route starts and ends at the same facility. The models differ from each other in their objective functions and on whether they include a capacity constraint. Alternative formulations are presented that use only binary variables, and are valid even when the input graph is not complete. This applies, in particular, to a compact two-index formulation for problems minimizing the overall routing costs, with or without facility setup costs. This formulation incorporates a newset of constraints that force the routes to be consistent and return to their original depots. A polyhedral study is presented for some of the formulations, which indicates that themain families of constraints are facet defining. All formulations are solved by branch and cut, and instances with up to 200 vertices are solved to optimality. Despite the difficulty of the problems, the numerical results demonstrate the good performance of the algorithm.</p

A branch-and-cut algorithm for the multidepot rural postman problem

This paper considers the Multidepot Rural Postman Problem, an extension of the classical Rural Postman Problem in which there are several depots instead of only one. The aim is to construct a minimum cost set of routes traversing each required edge of the graph, where each route starts and ends at the same depot. The paper makes the following scientific contributions: (i) It presents optimality conditions and a worst case analysis for the problem; (ii) It proposes a compact integer linear programming formulation containing only binary variables, as well as a polyhedral analysis; (iii) It develops a branch-and-cut algorithm that includes several new exact and heuristic separation procedures. Instances involving up to four depots, 744 vertices, and 1,315 edges are solved to optimality. These instances contain up to 140 required components and 1,000 required edges.Peer ReviewedPostprint (author's final draft

Antiprotozoal Activity of Benzoylthiourea Derivatives against Trypanosoma cruzi: Insights into Mechanism of Action

For decades, only two nitroheterocyclic drugs have been used as therapeutic agents for Chagas disease. However, these drugs present limited effectiveness during the chronic phase, possess unfavorable pharmacokinetic properties, and induce severe adverse effects, resulting in low treatment adherence. A previous study reported that N-(cyclohexylcarbamothioyl) benzamide (BTU-1), N-(tertbutylcarbamothioyl) benzamide (BTU-2), and (4-bromo-N-(3-nitrophenyl) carbamothioyl benzamide (BTU-3) present selective antiprotozoal activity against all developmental forms of Trypanosoma cruzi Y strain. In this study, we investigated the mechanism of action of these compounds through microscopy and biochemical analyses. Transmission electron microscopy analysis showed nuclear disorganization, changes in the plasma membrane with the appearance of blebs and extracellular arrangements, intense vacuolization, mitochondrial swelling, and formation of myelin-like structures. Biochemical results showed changes in the mitochondrial membrane potential, reactive oxygen species content, lipid peroxidation, and plasma membrane fluidity. In addition, the formation of autophagic vacuoles was observed. These findings indicate that BTU-1, BTU-2, and BTU-3 induced profound morphological, ultrastructural, and biochemical alterations in epimastigote forms, triggering an autophagic-dependent cell death pathwayCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES, Financial Code 01