Electrophysiological biosensors enables a novel way to measure electrical activity of biological structures both in-vitro and in-vivo and represents valuable alternative to current cellular activity measuring methods. Within this work we will be focusing on development of organic semiconductor (PEDOT:PSS) based Organic Electrochemical Transistors (OECTs) and optimization of material printing methods used in their development. These transistors are meant to be able to transfer electrochemical signals within the cell membrane to electrical signal. Such sensors should be used for cytotoxicity testing of chemicals and potential drugs on cardiomyocytes. Main benefits of OECTs are in their higher sensitivity thanks to their ability to locally amplify electric signals, better noise-signal ratio and outstanding biocompatibility. Their development is undemanding and inexpensive due material printing methods and materials processable at room temperatures.

This research project investigated the effectiveness of the Piotroski screen to select financially sound stocks from the upper quintile of high book-to-market value (growth) stocks on the Johannesburg Stock Exchange (JSE). The period chosen for this study was all the years since the publication of the Piotroski screen in 2000 until the most recent financial year, 2011.Although no conclusive evidence was found that the mean returns from the portfolio of financially strong firms that were selected by means of the Piotroski screen were significantly better than the portfolio of value stocks, it was strongly suspected that the small group of firms that were signified as financially the strongest by the Piotroski screen had a decreased probability of containing firms with negative one year buy-and-hold returns compared to the other portfolios. Although the outcome was inconclusive due to small sample sizes, it was also strongly suspected that the one year buy-and-hold strategy yielded returns that were in the order of almost four times better than the five year buy-and-hold strategy.It was recommended that, in order to minimise suboptimal investor behaviour caused by psychological biases on the JSE, investors should adopt a mechanical investment method based on objective financial statement analysis, using the Piotroski screen to select financially strong firms from the pool of value firms. It was further recommended that an annual portfolio balancing strategy should be used. / Dissertation (MBA)--University of Pretoria, 2012. / Gordon Institute of Business Science (GIBS) / unrestricted

Whole genome doubling (WGD) generates genetically unstable tetraploid cells that fuel tumorigenesis. Cells that undergo WGD must acquire adaptive characteristics to accommodate their tetraploid state, and these adaptations may confer unique vulnerabilities that can be exploited therapeutically. We analyzed the genomes of ~9,700 primary human cancer samples to uncover genetic alterations that are specifically enriched in WGD+ cancer cells. Through integrating our genetic analysis with gene essentiality data acquired from Project Achilles, we identified gene dependencies in WGD+ cells. Moreover, we identified genes that are essential for the viability of WGD+ cancer cells, but non-essential to non-transformed diploid cells. We demonstrated that the gene encoding for the mitotic kinesin KIF18A is dispensable for mitosis in diploid cells, but becomes critical for accurate chromosome segregation and viability in WGD+ cells, making it an attractive drug target. Collectively, this work revealed new strategies to specifically target WGD+ cancer cells, namely targeting the gene KIF18A, while sparing the normal diploid cells from which they arise. / 2022-06-04T00:00:00Z

Workshop Mensch-Computer-Vernetzung Web Accessibility Gestaltung von Webseiten um eine Nutzung mit vielen verschiedenen Zugangsmgeräten (Scrennreader, Bildschirmlupe) und unter verschiedenen technischen Bedingungen (langsame Anbindung, veraltete Software, keine Farbe) weitestgehend uneingeschränkt zu ermöglichen.

Spatial orientation of pigeons on a small scale was intensivelly studied in experiments using various types of arenas or mazes. In these experiments pigeons usually searched for food hidden in the goal area and they based their orientation on available landmarks. The development of new technologies allowed to test spatial cognition of pigeons also in virtual tasks, based exclusively on a schematic representation of an arena or maze on a touch screen. In experiments of this type pigeon marks the goal by pecking and it is rewarded by food from a feeder, located near the monitor. Study presented in this diploma thesis was based on combination of both types of spatial tasks. The information crucial for locating the goal was presented to pigeons on a computer screen in form of graphic stimuli, whereas the goal itself was formed by one of the 4 holes in corners of a transparent rectangular desk, standing in front of the monitor. Experiment with similar design was not yet published in the study of spatial cognition of pigeons. Two types of abstract graphic stimuli were tested. The first stimuli provided a spatial information about the location of a goal and had a form of small rectangular frame with a white spot in one of its corners. The frame represented the space of the response desk and the white spot...

Bakgrund: Datorspel kan ge en ökad dagtrötthet och försämrad sömnkvalitet hos individer som spelar mer än 2h/dag. Fysisk aktivitet har en akut positiv inverkan på många delar i sömnen såsom sömnkvalitet och dagtrötthet. Syftet med studien var att kartlägga den fysiska aktivitetsnivån och sömnsvårigheter hos datorspelande vuxna, samt undersöka ett eventuellt samband mellan fysisk aktivitet och sömnsvårigheter.  Metod: Författarna genomförde en icke experimentell kvantitativ tvärsnittsstudie med vuxna individer som spelade datorspel minst 2h/dag. 116 svar inkluderades till frågeställning 1 (internt bortfall till frågeställning 2 & 3 n = 20). En webbenkät publicerades i tre svenska Facebook-grupper inriktade mot datorspel för att kartlägga deltagarnas sömn samt fysisk aktivitet. Sömnen mättes med Insomnia Severity Index (ISI) och den fysiska aktiviteten mättes med International Activity Questionnaire Short Form (IPAQ-SF). Resultat: 70% av studiens respondenter hade “Inga kliniska sömnsvårigheter” enligt ISI och 59% bedömdes ha en hög aktivitetsgrad enligt IPAQ-SF. Det förekom inget signifikant samband mellan respondenternas sömnbesvär och fysiska aktivitet.  Diskussion: Förekomsten av sömnbesvär och antal deltagare som uppfyllde kriterierna för insomni var jämförbar med den svenska populationen. Vidare var respondenternas aktivitetsgrad högre än vad som tidigare setts i den svenska befolkningen. För att kunna se ett tydligare samband mellan dessa faktorer är bedömningen att det skulle krävas ett större urval med respondenter. / Background: Computer games can negatively impact sleep in individuals who play more than 2 hours/day. Physical activity can improve many parts of sleep such as sleep quality and less daytime fatigue. The purpose of the study was to map the level of physical activity and sleep difficulties in computer-gaming adults, and to investigate whether there is a correlation between physical activity and sleep difficulties. Method: The authors conducted a non-experimental quantitative cross-sectional study with computer-gaming adults who played at least 2 hours/day. 116 answers were included to question 1 (internal dropout to question 2 & 3 n = 20). A web-survey was published in three Swedish computer game-oriented Facebook groups to map the participants' sleep and physical activity. Sleep was measured with the Insomnia Severity Index (ISI) and physical activity was measured with the International Activity Questionnaire Short Form (IPAQ-SF) Results: 70% of the study respondents had “No clinical sleep difficulties” according to ISI and 59% were classified to have a high activity level according to IPAQ-SF. There was no significant association between the respondents' sleep difficulties and physical activity. Discussion: The occurrence of sleep difficulties and the number of participants who met the criteria for insomnia was comparable to the Swedish population. Furthermore, the respondents' degree of physical activity was higher than previously seen in the Swedish population. In order to be able to see a clearer connection between these factors, the assessment is that a larger selection of respondents would be required.

Particulate contamination of the optical surfaces of solar collectors, often called "soiling", can have a significant deteriorating impact on energy yield due to the absorption and scattering of incident light. Soiling has more destructive effect on concentrated solar systems than on flat-plate photovoltaic panels, as the former are incapable of converting scattered sunlight. The first part of this thesis deals with the soiling losses of flat-plate photovoltaic (PV), concentrated solar power (CSP), and concentrated photovoltaic (CPV) systems in operation in several regions of the world. Influential parameters in dust accumulation losses, as well as different cleaning mechanisms in pursuit of restoring the efficiency of soiled systems, have been thoroughly investigated. In lieu of the most commonly-practiced manual cleaning method of using high-pressure water jets, the concept of automatic dust removal using the electrostatic forces of electrodynamic screen (EDS) technology is in a developmental stage and on its way toward commercialization. This thesis provides comprehensive analytical solutions for the electric potential and electric field distribution in EDS devices having different configurations. Numerical simulations developed using finite element analysis (FEA) software have corroborated the analytical solutions which can easily be embedded into software programs for particle trajectory simulations while also providing flexibility and generality in the study on the effect of different parameters of the EDS on the electric field and ensuing dust-removal performance. Evaluation and comparison of different repelling and attracting forces exerted on dust particles is of utmost importance to a detailed analysis of EDS performance in dust removal. Hence, the balance of electrostatic and adhesion forces, including van der Waals and capillary forces, have received significant attention in this dissertation. Furthermore, different numerical analyses have been conducted to investigate the potential causes of observed failures of EDS prototypes that functioned well in a laboratory environment but failed after outdoor exposure. Experimental studies form the last two chapters of this dissertation. Different tests have been conducted on an EDS sample integrated with a PV cell to restore the efficiency of the cell after dust deposition. In order to evaluate the performance of the EDS in dust-particle removal, we have studied the particle size distribution on the EDS surface after each dust deposition and EDS cleaning cycle using a custom-built dust-deposition analyzer. Furthermore, we have pursued several experiments to examine how the geometric and operational EDS parameters affect particle charge via charge-to-mass-ratio measurements.

Die Verkleinerung der modernen Temperatursensoren ermöglicht die Volumenreduzierung der bisher angewandten Stevenson-Wetterhütten. Insbesondere bei automatischen Stationen finden wir wesentlich kleinere Strahlungsschutzeinrichtungen. Langjährige Beobachtungsreihen sind nicht mehr vergleichbar und müssen angepaßt werden. Es werden Einzelwertabweichungen für Temperaturen von mehr als 1 K genannt. Zur Lösung dieses Problems sind Vergleichsuntersuchungen und Anpassungsrechnungen erforderlich. / The minimisation of modern temperature sensors allows to reduce the volume ofthe up to now used Stevenson screens. Especially for automatic stations we found essential smaller radiationshields. Temperature observations of many years arc incomperable and had to be adapted. Errors of more as 1 K for single temperatures are mentioned. For the solution of this problem comparisons and adaptations are necessary.

This project explores the ability to use “smart” media devices for the TV set as platforms for interactive TV shows. The research approach was research-based design where a prototype was designed, developed, and evaluated with user tests. The project used a Swedish television game show called “På spåret” and an application for tvOS on Apple TV was developed, which allow users to play along with the show. The software implements a model-view-controller architecture and uses the AVFoundation framework for playing video streams together with the UIKit framework to create interactive overlay views. The interactive elements were synchronized with the video by the usage of metadata. The user test results show that the interactive TV show gained in both entertainment and excitement among the users. Further conclusions are that interactive elements can be available both during playing or paused video and the context should decide which mode. A multimodal interface with gestures and sound as feedback seems to be a good option, based on user tests. This project also presents a solution for user input with the remote, using a virtual keyboard together with filter function. The user filtering out the input from a data set to minimize the typing of letters. User tests show that the filter solution seems to be a good option for text input in a specific domain or category of allowed input. However, for free text input, a better method is required. / Detta projekt utforskar möjligheten att använda ”smarta” mediaspelare till TV-apparaten som plattform för interaktiva TV program. Forskningsmetoden var forskningsbaserad design där en prototyp designades och utvecklades som sedan utvärderades med användartest. Projektet använde sig av TV-programmet ”På spåret” som scenario och en applikation, som tillåter användare att spela med i programmet, utvecklades till Apple TV och tvOS. Applikationen implementerade model-view-controller-arkitektur och använde sig av ramverken AVFoundation samt UIKit för att skapa interaktiva överläggsvyer på en video-vy med strömmande video. De interaktiva inslagen synkades med videon med hjälp av metadata. Användartesterna visar på att det interaktiva TV-programmet ökade både i underhållningsvärde och i exaltation hos testpersonerna. Vidare slutsatser är att interaktivitet kan implementeras både under spelande och pausad video, och vilket man väljer är det som passar videoinnehållet bäst. Multimodala interaktioner såsom gester och feedback med ljud rekommenderas baserat på användartesterna. I detta projekt presenteras också en lösning för användarinput med fjärrkontrollen. Med ett virtuellt tangentbord filtrerar användaren ut sin inputdata utifrån en bestämd datamängd, vilket minimerar antalet skrivna bokstäver. Användartester bekräftar att filterlösningen är ett bra alternativ för inmatning i en specifik kategori av tillåten input. För helt fri textinmatning behövs dock bättre metoder.

De senaste åren har trenden att använda en second screen i samband med tv-tittande ökat till följd av den ökade användningen av smartphones och surfplattor. Det ökade second screen-användandet medför att innehållet som visas på tv får mindre uppmärksamhet av tittarna. En möjlig lösning för att motverka detta är så kallade programspecifika second screen-applikationer som syftar till att komplettera innehållet som visas på tv och ge tittaren ett mervärde. Denna rapport syftar till att identifiera användningsmönster för en programspecifik second screen-applikation som används under livesända ishockeymatcher samt vilka faktorer som påverkar mönstren. Applikationen består av ett flöde som innehåller inlägg relaterade till matchen, t.ex. kommentarer och videoklipp från sportprofiler samt frågor som tittaren kan besvara och därmed se andra tittares åsikter om olika situationer i matchen. Rapporten diskuterar även förslag på hur resultaten kan användas vid utformandet av flödesbaserade second screen-applikationer samt hanteringen av innehållet i flödet. För att identifiera användningsmönstren utfördes användarobservationer, direkt följda av kompletterade intervjuer, under fem direktsända ishockeymatcher med fem olika användare som ensamma tittade på en match. Resultaten av studien visar att användningsmönstren huvudsakligen påverkas av de olika delarna i sändningen (speltid, studioanalys och reklamavbrott) samt spänningen i matchen. De olika funktionerna i applikationen samt användandet av andra applikationer är också faktorer som påverkar användandet. Resultaten visar även att användarna värdesätter att känna samhörighet med andra som tittar på matchen när de tittar på en match ensam. / The trend of interacting with a second screen while watching TV has evolved over the past years with the increased usage of smartphones and tablets. One program genre in which second screen usage is common is sports. The increasing second screen usage has made it challenging to keep viewers engaged in the content being shown on the TV. A possible solution to this problem is program-specific second screen applications that serve to complement the TV content and give an added value to the viewer. This paper aims to identify usage patterns of a program-specific second screen application, used during broadcasts of live hockey games. The application consists of a feed that contains posts related to the game such as comments and videos posted by sport profiles and editors, and polls that the viewer can answer to see other viewers’ thoughts about different situations in the game. Moreover, the paper analyzes what factors affect the usage patterns and discusses how the findings could be used when developing and managing the content of a feed-based second screen application during a sports game. To identify the usage patterns of the application a triangulation approach was used. Five user observations, directly followed by complementing semi-structured interviews were conducted during five separate live hockey games broadcast on TV. The results show that the usage patterns of the application are mainly affected by the excitement and the different parts of the broadcast (game time, studio analysis and commercial breaks), the different features of the application and the usage of other applications. Moreover, the results highlight the importance of feeling connected to other remote viewers of the game through the application when watching a game alone.