Pseudomonas is the most common cause of chronic lung infections leading to death in cystic fibrosis patients. While chronic infection is extremely difficult to eradicate, the initial bacterial-host interactions prior to biofilm formation and establishment of chronic infections represents an attractive therapeutic target. It is clear that interaction between pathogens and the host is a very complex process and successful adaptation requires tight control of virulence factor expression. The aim of this project was to look for early changes in P. aeruginosa global gene expression in response to attachment to epithelial cells. P. aeruginosa PA01 was incubated with polarized HBE cells at a MOI of 100 for 4 hours and bacteria attached to epithelial cells (interacting) were collected separately from those in the supernatant (non-interacting). To minimize media effects observed by others, iron and phosphate were supplemented at appropriate levels to avoid expression changes due to limitation of these nutrients, as confirmed in our microarray experiments. Analysis of 3 independent experiments demonstrated that 766 genes were up or down regulated by more than 1.5 fold during attachment. Among these, 371 genes, including ion, oprC, as well as 3 genes in quorum-sensing systems and 9 genes involved in the pmrAB and phoPQ two-component regulatory systems were found to be induced in the interacting bacteria. On the other hand, 395 genes, including oprG outer membrane porin and pscP involved in type III secretion system were down regulated. To understand the roles of these differentially expressed genes, a cytotoxicity (LDH release) assay was performed and demonstrated that oprG and ion mutants were less capable than the wild type of killing HBE epithelial cells. These findings suggest that, under these interaction assay conditions, regulation of the expression of certain virulence factors provides a potential advantage for successful adaptation. In addition, a mutant lacking a filamentous hemagglutinin like protein was found to be less cytotoxic to HBE cells and also deficient in A549 epithelial cell binding, indicating that this probable non-pilin adhesin has multiple functions in P. aeruginosa. / Science, Faculty of / Microbiology and Immunology, Department of / Graduate

Iron homeostasis is essential for maintaining the physiological requirement for iron while preventing iron overload. Multicopper ferroxidases regulate the oxidation of Fe(II) to Fe(III), circumventing the generation of harmful hydroxyl-free radicals. Ceruloplasmin is the major multicopper ferroxidase in blood; however, hephaestin, a membrane-bound ceruloplasmin homolog, has been implicated in the export of iron from duodenal enterocytes into blood. These ferroxidases supply transferrin, the iron-carrier protein in plasma, with Fe(III). Transferrin circulates through blood and delivers iron to cells via the transferrin receptor pathway. Due to the insoluble and reactive nature of free Fe(III), the oxidation of Fe(II) upon exiting the duodenal enterocyte may require an interaction between the ferroxidase and transferrin. In Chapter 3, the putative interaction of transferrin with ceruloplasmin and a soluble form of recombinant hephaestin was investigated. Utilizing native polyacrylamide gel electrophoresis, covalent cross-linking and surface plasmon resonance, a stable interaction between the two proteins was not detected. The lack of interaction between hephaestin and transferrin prompted the investigation into the localization of hephaestin in the human small intestine. Hephaestin has been reported to have both intracellular and extracellular locations in murine tissue. In the Appendix, the location of hephaestin in human tissue was investigated using a novel polyclonal antibody. Hephaestin was localized to the basolateral membrane and an intracellular location of the enterocyte, as well as a novel location in the myenteric plexus of the duodenum. The delivery of iron to cells via the transferrin receptor pathway is well established; however, little is known about the interaction of transferrin with the transferrin receptor at the molecular level. In Chapters 4 and 5, surface plasmon resonance was employed to further characterize the binding event between transferrin and the transferrin receptor. It was found that mutations affecting iron release in transferrin did not impact receptor binding. However, when N-lobe residues predicted to form contacts with the transferrin receptor were targeted, significant changes in the transferrin receptor binding kinetics and affinity were observed. / Medicine, Faculty of / Biochemistry and Molecular Biology, Department of / Graduate

Computer systems with all their potential could be employed as powerful tools to assist the artist during the creative process of picture making. The complex process of picture making is tentative, indeterminate, explorative and unpredictable. Perceptual uncertainty of patterns on the canvas may have an important role during such a process. For the artist, the perception of a new or alternative structure in an already structured image is plausible, his subsequent interaction with the media being consistent with this revised view of the image. Therefore, it is essential for the computer system to be able to structure and restructure the image in terms of the interpretations perceived by the artist.

This study was concerned with (i) experiential factors which affect the development of trust and suspicion, and (ii) the effects of trust and suspicion upon bargaining and, negotiations. Essentially, the experiment consisted of an orthogonal 2x2x3 factorial design with one control group. Altogether, 112 male undergraduates comprised the final sample. Particular emphasis was placed upon developing an approach that could overcome some of the methodological problems that have been inherent in previous attempts to study trust and suspicion. To this end, the experiment was designed to allow (on the basis of the observation of the subjects' responses) valid inferences, about trust and suspicion. For example, subjective trust and suspicion were distinguished from manifest trust and suspicion, and were measured on the basis of responses related to a one-trial sequentially-played game. Moreover, the game involved a payoff matrix that was meaningful to the subjects insofar as it was possible for the subjects to incur real losses of their own money apparently as a result of the untrustworthy behavior of one of the other subjects. With respect to the development of trust and suspicion as a function of previous experience, it was found that: (1) previous trustworthiness engendered trust whereas previous untrustworthiness generated suspicion; (2) suspicion was established more easily than trust; however, (3) where previously the incentive to betray had been high, trust was greater especially if the other person (0) had resisted the lucrative temptation to betray. Of methodological interest was a related finding that the tendency to manifest trust or suspicion was closely related to the underlying (subjective) state of trust or suspicion. The nature of this relationship in terms of certainty and uncertainty was, however, more clear-cut for those who manifested suspicion than for those who manifested trust. While the former were certain that 0 would be untrustworthy, the latter manifested trust toward 0 even though they were uncertain as to whether 0 would be trustworthy or not. In the second part of the study, both trust and suspicion were found to be important in influencing bargaining and negotiations in a number of respects. With regard to the duration of bargaining, the trust group required less time to reach agreements than did the suspicion group. Several reasons for this finding were evident. First, subjects in the suspicion group made initial offers that were more extreme than the initial offers made by the subjects in the trust group. Secondly, subjects in the suspicion group appeared to be more concerned with the objective of modifying each other's utilities. This was reflected in the finding that the communications of the suspicion group (compared with the trust group) were characterized more by lies, threats, and ultimatums, and less by genuine and sincere attempts to exchange information; also, subjects in the suspicion group made more checks on each other and made more refusals to bargain that did the subjects in the trust group. In relation to the nature (location) of the solution, trust and suspicion appeared to have no overall effect upon whether settlements were made at equality or equity. There was, however, a prevalence of settlements at equality (regardless of whether trust or suspicion was operating). The interesting feature about this result was that the equality that was obtained in a context of suspicion was hard-earned over a prolonged period of time, whereas the equality that was agreed upon in the context of trust was relatively easily achieved. It was therefore concluded that even if the nature of the solution were not affected by suspicion, bargaining under a certain amount of trust would be preferable to bargaining under a high degree of suspicion; for under extreme suspicion, task-oriented behavior becomes easily disrupted and reduced to time-consuming conflict. / Arts, Faculty of / Psychology, Department of / Graduate

Two contradictory social psychological models of human sociability exist in the social science literature: a steady state model, and a homeostatic model. In this thesis a model of possible environmental effects on individual solitary behavior is developed to test these underlying social psychological models. These models are tested in a secondary analysis of activity log data of a sample of industrial workers. The results indicate that two causal processes interact in producing differences in the amounts of time people spend alone. In one process, temporal constraints on the number of persons and the amount of time available for non-work social interactions facilitate solitary behavior on workdays. These direct effects carry over into the weekend when the constraints of work hours are not directly present. In the other process people compensate for extremes in their social experience at work by participating more in discretionary solitary activities. When combined, these two isolating processes produce an even stronger interaction effect. These observations support the homeostatic model of human sociability. Suggestions are then made for a more sophisticated future testing of these models. / Arts, Faculty of / Sociology, Department of / Graduate

Synoptic and climatological dynamic studies generally rely on bulk aerodynamic flux formulae to describe air-sea heat and momentum exchange on synoptic and climatological scales. Barometric pressure maps (which involve an intrinsic temporal averaging of the wind) and wind roses provide two sources of spatial and temporal wind information for flux calculations. Several investigators have shown that, due to the non-linear dependence of the bulk aerodynamic formulae on the winds, time-averaged estimates of the fluxes based on vector averaged winds systematically underestimate the actual time-averaged fluxes. Using 10 to 21 years of three-hourly sampled sea surface meteorological observations from 9 weatherstations in the North Atlantic Ocean and 2 weatherstations in the North Pacific Ocean, the three-hourly stresses, latent heat fluxes and sensible heat fluxes were calculated. The sampled data and the calculated fluxes were then averaged over periods varying up to 28 days. The estimates of the averaged fluxes based on the vector averaged winds were then compared to the directly averaged values. A simple analysis revealed that an upper bound for the difference in the two stress calculations was directly proportional to the sum of the x and y component wind variances lost through the averaging process (in agreement with Fofonoff, 1960) and inversely proportional to the square of the vector averaged wind speed. The wind averaged and directly averaged flux estimates were grouped according to the Beaufort wind speed category and the period over which the variates were averaged. .A multivariate regression was then performed to optimize a transformation from the wind averaged to the directly averaged case. For all fluxes, the transformation dramatically improved the wind averaged estimates of the climatological means and variances of the directly averaged fluxes. The residual error between the two estimates was decreased up to a factor of 5 over the uncorrected case and the correlation coefficients showed a moderate increase. The regression coefficients showed similar values for all temperate latitude stations. Based on consistencies observed in the wind speed and averaging period dependencies of the multivariate coefficients, an empirical formula was found which interpolated the wind speed and averaging dependence and duplicated the multivariate regression results. The data from the ten temperate latitude stations were grouped and a single formula found which only moderately increased the errors between the wind-averaged and directly averaged estimates. The geographically averaged formula was not applicable at Station N, located at the northern extremity of the North Pacific Trade Wind- region. Analysis of the 28 day wind-averaged flux spectral estimates showed that they underestimated the 28 day directly averaged flux spectral estimates. Application of the specific ship empirical formula greatly improved agreement between the two spectral densities and reduced the residual series power density at all frequencies. High latent heat flux errors at Station N, could be reduced by application of a seasonal correction. The data were also grouped into monthly wind rose configurations and the wind rose monthly flux estimates were compared to the directly calculated long-term monthly mean fluxes. In all cases, the wind rose fluxes compared favourably with the directly calculated fluxes. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Advertising is an essential way of communicating value to the audience. Adlede does this with context in focus when finding articles with right content to the right campaigns. To know if matching articles are good, advertisers need to get statistics from the campaign. Today a tool for this does not exist. This master thesis analyses, how to best develop a self-serve, user-friendly campaign management tool for publishing a campaign and shows results from the campaign.   This thesis design and create a concept of a management tool with help of frequently used UX design method. To get a solution for this concept, interviews, designs, prototypes and user testing have taken place. A final design suggestion has been determined.

L'entrée multi-points offre un canal d'interaction très expressif pour les dispositifs équipés d'une technologie tactile multi-points. Cependant, alors que la taille du canal de communication est, en théorie, très grande, la plupart des systèmes n'en font, en pratique, qu'un usage très limité. Cet état de fait est probablement dû à la difficulté de gérer un grand nombre de gestes multi-points pour deux raisons principales: (1) les limites cognitives et motrices des humains et (2) les difficultés techniques pour l'élaboration de systèmes de reconnaissance robustes. Cette thèse étudie une nouvelle technique d'entrée, TouchTokens, pour enrichir le vocabulaire de gestes multi-points, en se basant sur la position relative des points de contact et des objets (tokens) passifs. Un TouchToken est un "token" passif avec des encoches qui indiquent à l'utilisateur comment l'attraper, et qui est donc associé à une configuration de doigts qui lui est propre. Ainsi, lorsque les utilisateurs tiennent un token tout en étant en contact avec la surface, le système reconnaît le schéma de points de contact correspondant avec une grande robustesse. Nous commençons par présenter le principe avec des tokens rigides de forme basique. L'algorithme de reconnaissance et la conception des tokens sont issus des conclusions d'une étude formative dans laquelle nous avons collecté et analysé des schémas de points de contact lorsque les utilisateurs tiennent des tokens de taille et de forme variable. Cette première étude montre que les utilisateurs ont des stratégies individuelles cohérentes, mais que ces stratégies dépendent de l'utilisateur. Ces conclusions nous ont menés à l'élaboration de tokens avec des encoches afin que les utilisateurs attrapent un même token toujours de la même façon. L'expérience que nous avons menée sur ce nouvel ensemble de tokens démontre que nous pouvons les reconnaître avec un niveau de robustesse supérieur à 95%. Nous discutons les rôles que peuvent jouer les TouchTokens dans les systèmes interactifs, et nous présentons un échantillon d'applications de démonstration. La conception initiale des TouchTokens ne supporte qu'un ensemble d'interactions se limitant au modèle à deux états de l'interaction directe. Dans un second projet, nous décrivons une technique de fabrication avec une découpeuse laser qui permet de faire des tokens flexibles que les utilisateurs peuvent, par exemple, courber ou compresser en plus de les faire glisser sur la surface. Nous augmentons notre reconnaisseur pour analyser les micro-mouvements des doigts pendant la manipulation du token afin de reconnaître ces manipulations. Cette approche basée sur l'analyse des micro-mouvements des doigts nous permet également de discriminer, lorsque l'utilisateur enlève ses doigts de la surface, le cas où il enlève le token de la surface, du cas où le token est resté sur la surface. Nous rapportons sur les expériences que nous avons menées pour déterminer la valeur des paramètres de nos différents reconnaisseurs, et tester leur robustesse. Nous obtenons des taux de reconnaissance supérieurs à 90% sur les données collectées. Nous finissons cette thèse par la présentation de deux outils qui permettent de construire et reconnaître des tokens de forme arbitraire, TouchTokenBuilder and TouchTokenTracker. TouchTokenBuilder est une application logicielle qui permet de placer des encoches sur des contours vectoriels de forme arbitraire, et qui alerte en cas de conflit de reconnaissance entre tokens. TouchTokenBuilder produit deux fichiers en sortie: une description vectorielle des tokens pour leur construction, et une description numérique servant à leur reconnaissance. TouchTokenTracker est une librairie logicielle qui prend cette description numérique en entrée, et qui permet aux développeurs de traquer la géométrie (position, orientation et forme) des tokens au cours de leur manipulation sur la surface. / This thesis investigates a novel input technique for enriching the gesture vocabulary on a multi-touch surface based on fingers' relative location and passive tokens. The first project, TouchTokens, presents a novel technique for interacting with multi-touch surfaces and tokens. The originality is that these tokens are totally passive (no need for any additional electronic components) and their design features notches that guide users' grasp. The purpose of the notches is to indicate a finger spatial configuration (touch pattern) that is specific to the token. When users hold a token and place it on the surface, touching them simultaneously, the system can recognize the resulting touch patterns with a very high level of accuracy (>95%). This approach works on any touch-sensitive surface and makes it possible to easily build low-cost interfaces that combine no-conductive tangibles and gestural input. This technique supports a new multi-touch input that the system can recognize. However, the interaction is limited to the two-state model of touch interaction as the system only knows the tokens' position and cannot detect tokens that are not touched. In the second project of the thesis, we introduce a laser-cut lattice hinge technique for making the tokens flexible. We then develop a new recognizer that analyzes the micro-movements of the fingers while user are holding and deforming those tokens on the surface. We run three experiments to design and calibrate algorithms for discriminating the three following types of manipulations: (1) when a token is left on the surface rather than taken off it (On/Off); (2) when a token has been bent, and (3) when it is squeezed. Our results show that our algorithms can recognize these three manipulations with an accuracy of: On/Off 90.1%, Bent 91.1% and Squeezed 96,9%.The thesis concludes with the presentation of two tools, TouchTokenBuilder and TouchTokenTracker, for facilitating the development of tailor-made tangibles using a simple direct-manipulation interface. TouchTokenBuilder is a software application that assists interface designers in placing notches on arbitrarily-shaped vector contours for creating conflict-free token sets and warning them about potential conflicts. It outputs two files: a vector-graphics description of all tokens in the set and a numerical description of the geometry of each token. TouchTokenTracker is a software library that takes as input the numerical description produced by TouchTokenBuilder, and enables developers to track the tokens' full geometry (location, orientation and shape) throughout their manipulation on the multi-touch surface.

The Gautrain Rapid Rail Link (GRRL) is a rail transit system in South Africa that links Johannesburg and Pretoria, as well as Johannesburg and the O.R. Tambo International Airport. Travelling at speeds of up to 160 km/h, the Gautrain system is the first of its kind on the African continent. This dissertation covers an investigation into the relationship between the vertical and lateral forces, speed and superelevation in a GRRL curve. The research described in this dissertation is based on an experiment which involved running a test train through a curve at various speeds, changing the cant of the curve by tamping and repeating the train runs. The cant was changed due to high wheel wear rates. The curve already had a cant deficiency, and this cant deficiency was subsequently increased by reducing the curve’s cant. Assessing the before and after tamping test data validated the existence of the expected relationships between the vertical and lateral rail forces, the speed and the cant. The change in cant had a minimal effect on the magnitude of the vertical forces, although a transfer of loading between the high and low legs did occur. The theory indicates that the 14 % reduction in cant in this curve given all of the other curve characteristics should have resulted in an increase in the lateral forces. There was however a roughly 50 % reduction in the maximum lateral forces after the cant was reduced that can be explained from a train dynamics point of view. In addition, there was an increase in safety due to a reduced derailment ratio at this curve’s normal operating speed of 85 km/h. It is not unreasonable to presume that a 50 % reduction in the maximum lateral forces could lead to a halving of the wear rate of the rail and wheels in this curve with similar results to be expected in other curves on the rail network. / Dissertation (MEng)--University of Pretoria, 2016. / The Chair in Railway Engineering at the University of Pretoria / Civil Engineering / MEng / Unrestricted

During the last decades Europe has seen an increase in the number of refugees coming to the region. When arriving in a new country one faces several challenges to overcome. In Sweden, a lot of the services the government provides regarding immigration, social insurance, and health care are digital. This can on some occasions create a situation where the user of these services can not speak or write any of the languages available in the service. This thesis aims to investigate what aspects of user experience design that could support a user completing tasks and understanding context in a digital setting even though the language might not be fully understood. By looking at the aspects of cross-cultural design, design for illiterate users, and understanding icon design, a prototype was developed and tested on users not literate in the language used. The results showed that the users were able to complete the task given, and understand the context.