Diamidines are compounds with antiparasitic properties that target the minor groove of DNA. The mechanism of action of these compounds is unknown, but topological changes to DNA structure are a possibility. In this study, we have developed a polyacrylamide gel based screening method to determine topological effects of diamidines on four target sequences: AAAAA, TTTAA, AAATT, and ATATA. The changes caused are sequence dependent, but generally the effect on AAAAA and AAATT is the same while the effect on TTTAA and ATATA is the same. A few compounds show interesting sequence dependent topological effects in the polyacrylamide screening method that could be caused by the compound forming a dimer. Mass spectrometry is used to determine the stoichiometry of DNA-compound complexes. Once compounds show topological effects in the screening method, a bent fragment of kinetoplast DNA is isolated to determine if the same effects occur with DNA from a parasite.

This thesis explores the emerging issue of cities and countries competing for international students as part of market and talent-based economic development strategies. Based on case studies in London, UK and Toronto, Canada, this research draws on interviews with senior policy-makers as well as international students completing their overseas studies to examine three issues. First, this thesis investigates the process by which similar policies to attract and retain greater numbers of international students have been developed and introduced in both countries. Arguing that these policies are “mobile,” this thesis demonstrates how the competitive interconnectedness of policy-making leads to the transfer of policy ideas from one jurisdiction to another, while also recognizing the mediating role of institutions for contributing to continued geographic differences in the policy landscape regarding international education. Second, it examines the decision-making process for international graduate students upon the moment of graduation with regard to their settlement and employment strategies. Through a comparison of international students finishing advanced degrees in science and engineering in both sites, it reveals the extent to which students’ plans involve the complex intermingling of personal, professional and (im)migration regulation factors. The confluence of these factors tend to pull students in different geographic directions, indicating that the conventional ‘stay or return’ construct is too simplistic as a framework for understanding students’ future movements. Moreover, the comparison of students’ strategies in the two sites illustrates the differential effect of multi-scalar institutional frameworks in constructing certain types of migrant subjects. Third, this thesis investigates how career development strategies of international students differ according to broad disciplinary differences. Contrasting the career plans of graduating students in science, engineering, and art and design programs, this research finds that there are key differences in the socio-spatial career strategies held by international students in line with the differentiated knowledge bases literature.

This dissertation is comprised of three papers. In Chapter 1 I analyze if career heterogeneity in terms of life-cycle earnings, occupational mobility and unemployment is predominantly driven by skills acquired prior to labor market entry or by decisions made and shocks accumulated over the working life. My study is based on a Dynamic Discrete Choice model that enriches the proto-typical dynamic Roy-model with a number of potentially important sources of career heterogeneity, such as match heterogeneity and permanent shocks to skills. I find that a large fraction of life-cycle income inequality is driven by match heterogeneity among workers with the same observable and unobservable credentials. Differences in comparative advantages, though quantitatively important as well, have a much smaller impact than what has been found in research that relies on estimates from more restrictive dynamic Roy models. In Chapter 2 I estimate a flexible non-stationary variance components model of residual earnings dynamics and investigate if recent increases in residual inequality are caused by an increase of the variances of permanent, persistent or transitory shocks. My results suggest that underlying sources of increasing wage inequality are very different across education groups. Most importantly, only the lesser educated experience a large increase in earnings instability. Chapter 1 and 2 utilize a unique administrative data set from Germany that follows workers from the time of labor market entry until twenty-three years into their careers. In the last chapter I investigate empirically if a particular set of pre-labor market skills – namely university student achievement – can be fostered by assigning male teachers to male students and female teachers to female students. I find that being taught by a same-sex instructor helps students to improve their relative grade performance and the likelihood of completing a course, but the magnitudes of these effects are small.

This thesis explores the emerging issue of cities and countries competing for international students as part of market and talent-based economic development strategies. Based on case studies in London, UK and Toronto, Canada, this research draws on interviews with senior policy-makers as well as international students completing their overseas studies to examine three issues. First, this thesis investigates the process by which similar policies to attract and retain greater numbers of international students have been developed and introduced in both countries. Arguing that these policies are “mobile,” this thesis demonstrates how the competitive interconnectedness of policy-making leads to the transfer of policy ideas from one jurisdiction to another, while also recognizing the mediating role of institutions for contributing to continued geographic differences in the policy landscape regarding international education. Second, it examines the decision-making process for international graduate students upon the moment of graduation with regard to their settlement and employment strategies. Through a comparison of international students finishing advanced degrees in science and engineering in both sites, it reveals the extent to which students’ plans involve the complex intermingling of personal, professional and (im)migration regulation factors. The confluence of these factors tend to pull students in different geographic directions, indicating that the conventional ‘stay or return’ construct is too simplistic as a framework for understanding students’ future movements. Moreover, the comparison of students’ strategies in the two sites illustrates the differential effect of multi-scalar institutional frameworks in constructing certain types of migrant subjects. Third, this thesis investigates how career development strategies of international students differ according to broad disciplinary differences. Contrasting the career plans of graduating students in science, engineering, and art and design programs, this research finds that there are key differences in the socio-spatial career strategies held by international students in line with the differentiated knowledge bases literature.

This dissertation is comprised of three papers. In Chapter 1 I analyze if career heterogeneity in terms of life-cycle earnings, occupational mobility and unemployment is predominantly driven by skills acquired prior to labor market entry or by decisions made and shocks accumulated over the working life. My study is based on a Dynamic Discrete Choice model that enriches the proto-typical dynamic Roy-model with a number of potentially important sources of career heterogeneity, such as match heterogeneity and permanent shocks to skills. I find that a large fraction of life-cycle income inequality is driven by match heterogeneity among workers with the same observable and unobservable credentials. Differences in comparative advantages, though quantitatively important as well, have a much smaller impact than what has been found in research that relies on estimates from more restrictive dynamic Roy models. In Chapter 2 I estimate a flexible non-stationary variance components model of residual earnings dynamics and investigate if recent increases in residual inequality are caused by an increase of the variances of permanent, persistent or transitory shocks. My results suggest that underlying sources of increasing wage inequality are very different across education groups. Most importantly, only the lesser educated experience a large increase in earnings instability. Chapter 1 and 2 utilize a unique administrative data set from Germany that follows workers from the time of labor market entry until twenty-three years into their careers. In the last chapter I investigate empirically if a particular set of pre-labor market skills – namely university student achievement – can be fostered by assigning male teachers to male students and female teachers to female students. I find that being taught by a same-sex instructor helps students to improve their relative grade performance and the likelihood of completing a course, but the magnitudes of these effects are small.

A good understanding of the relationship between highway performance, such as crash rates and travel delays, and winter road maintenance activities under different winter weather and traffic conditions is essential to the development of cost-effective winter road maintenance policies and standards, operation strategies and technologies. This research is specifically concerned about the mobility benefit of winter road maintenance. A microscopic traffic simulation model is used to investigate the traffic patterns under adverse weather and road surface conditions. A segment of the Queen Elizabeth Way (QEW) located in the Great Toronto Area, Ontario is used in the simulation study. Observed field traffic data from the study segment was used in the calibration of the simulation model. Different scenarios of traffic characteristics and road surface conditions as a result of weather events and maintenance operations are simulated and travel time is used as a performance measure for quantifying the effects of winter snow storms on the mobility of a highway section. The modeling results indicate that winter road maintenance aimed at achieving bare pavement conditions during heavy snowfall could reduce the total delay by 5 to 36 percent, depending on the level of congestion of the highway. The simulation results are then applied in a case study for assessing two maintenance policy decisions at a maintenance route level.

Biltrafiken bidrar till flera av Sveriges stora miljöproblem. Samtidigt har bilen haft en självklar plats i samhällsplaneringen och städers utformning har anpassats efter att många använder sig dagligen av fordonet. För att minska bilanvändandet är den fysiska utformningen av våra samhällen viktiga men också människors beteende. Mobility management innefattar en rad åtgärder för att just påverka människors beteende och attityder för att främja ett mer, främst miljömässigt, hållbart resande. I denna uppsats undersöks om uppställda förslag, från rapporten MaxLupoSE, kring hur mobility management kan integreras i samhällsplaneringen har potential att implementeras i Stockholm stad. Detta har undersökts genom samtal med tjänstemän inom Stockholm stad, tjänstemän på andra kommuner och representanter från byggföretag som är verksamma som byggherrar inom staden. Okunskap om effekterna hos mobility management-åtgärder samt osäkerhet kring hur detaljstyrande som staden kan vara kring dessa frågor i samhällsplaneringen är de två stora hinder som redogörs för i denna uppsats. Till detta kan tilläggas att arbetet med mobility management måste komma in tidigt i planprocessen, bygglov anses för sent av såväl byggherrar som tjänstemän. Inställningen till mobility management och osäkerheten kring detaljstyrningen kan även kopplas till tidigare forskning inom området som visar att förankring och motivering av åtgärderna är viktigt. Samtidigt kan det diskuteras huruvida en diskurs om bilens självklara plats i samhällsplaneringen ligger bakom den okunskap som finns om mobility management. Slutligen kan det konstateras att MaxLupoSE kan komma till bukt med dessa hinder genom klarare riktlinjer men att det i grunden handlar om vilka politiska mål som sätts upp för samhällsbyggandet.

A good understanding of the relationship between highway performance, such as crash rates and travel delays, and winter road maintenance activities under different winter weather and traffic conditions is essential to the development of cost-effective winter road maintenance policies and standards, operation strategies and technologies. This research is specifically concerned about the mobility benefit of winter road maintenance. A microscopic traffic simulation model is used to investigate the traffic patterns under adverse weather and road surface conditions. A segment of the Queen Elizabeth Way (QEW) located in the Great Toronto Area, Ontario is used in the simulation study. Observed field traffic data from the study segment was used in the calibration of the simulation model. Different scenarios of traffic characteristics and road surface conditions as a result of weather events and maintenance operations are simulated and travel time is used as a performance measure for quantifying the effects of winter snow storms on the mobility of a highway section. The modeling results indicate that winter road maintenance aimed at achieving bare pavement conditions during heavy snowfall could reduce the total delay by 5 to 36 percent, depending on the level of congestion of the highway. The simulation results are then applied in a case study for assessing two maintenance policy decisions at a maintenance route level.

As an increasing proportion of the world’s population travels ever-longer distances between their home and place of work, urban mobility networks have had to cope with this dramatic increase in movement. These networks not only occupy escalating amounts of undeveloped land, but also work to re-shape the public spaces and landscapes of the urban realm. The City of Toronto’s mobility (or increasing lack thereof) has an enormous influence on its culture and urban development; the car and its attendant infrastructures heavily govern the city’s growth by supporting urban sprawl. In order to redevelop public space, equalize access to mobility, and improve the way we move through the city, a new system of infrastructure is required; one that can negotiate through an asphalt-dominated landscape while creating a sustainable transport alternative. This thesis proposes new mobility networks as strategies of intensification through a repositioning of the bicycle and by prioritizing its supporting infrastructure along existing underutilized service lands in the City of Toronto. By further developing both the rail and hydro corridors as a city-wide network of mobility paths, and eventually phasing them into a series of linear parkways, distant parts of the city would become accessible for long-haul trips. The second design component is a series of bicycle hubs located at, and tailored to, strategic locations throughout the city’s existing corridors and transit lines. These new civic amenities have the potential to enrich urban placemaking, while acting as social centres that anchor newly connected communities.

Limited mobility of mobile ground robots in highly unstructured environments is a problem that inhibits the use of such robots in applications with irregular terrain. Furthermore, applications with hazardous environments are good candidates for the use of robotics to reduce the risk of harm to people. Urban search and rescue (USAR) is an application where the environment is irregular, highly unstructured and hazardous to rescuers and survivors. Consequently, it is of interest to effectively use ground robots in applications such as USAR, by employing mobility enhancement techniques, which stem from the robot’s mechanical design. In this case, a robot may go over an obstacle rather than around it. In this thesis the Reconfigurable Robot Team of Mobile Modules with Manipulators (R2TM3) is proposed as a solution to limited mobility in unstructured terrains, specifically aimed at USAR. In this work the conceptualization, mechatronic development, controls, implementation and testing of the system are given. The R2TM3 employs a mobile modular system in which each module is highly functional: self mobile and capable of manipulation with a five degree of freedom (5-DOF) serial manipulator. The manipulator configuration, the docking system and cooperative strategy between the manipulators and track drives enable a system that can perform severe obstacle climbing and also remain highly manoeuvrable. By utilizing modularity, the system may emulate that of a larger robot when the modules are docking to climb obstacles, but may also get into smaller confined spaces by using single robot modules. The use of the 5-DOF manipulator as the docking device allows for module docking that can cope with severe misalignments and offsets – a critical first step in cooperative obstacle management in rough terrain. The system’s concept rationale is outlined, which has been formulated based on a literature review of mobility enhanced systems. Based on the concept, the realization of a low cost prototype is described in detail. Single robot and cooperative robot control methods are given and implemented. Finally, a variety of experiments are conducted with the concept prototype which shows that the intended performance of the concept has been met: mobility enhancement and manoeuvrability.