Advancing image quantification methods and tools for analysis of nanoparticle electrokinetics

Image processing methods and techniques for high-throughput quantification of dielectrophoretic (DEP) collections onto planar castellated electrode arrays are developed and evaluated. Fluorescence-based dielectrophoretic spectroscopy is an important tool for laboratory investigations of AC electrokinetic properties of nanoparticles. This paper details new, first principle, theoretical and experimental developments of geometric feature recognition techniques that enable quantification of positive dielectrophoretic (pDEP) nanoparticle collections onto castellated arrays. As an alternative to the geometric-based method, novel statistical methods that do not require any information about array features, are also developed using the quantile and standard deviation functions. Data from pDEP collection and release experiments using 200 nm diameter latex nanospheres demonstrates that pDEP quantification using the statistic-based methods yields quantitatively similar results to the geometric-based method. The development of geometric- and statistic-based quantification methods enables high-throughput, supervisor-free image processing tools critical for dielectrophoretic spectroscopy and automated DEP technology development

Self-Assembly of DNA Graphs and Postman Tours

DNA graph structures can self-assemble from branched junction molecules to yield solutions to computational problems. Self-assembly of graphs have previously been shown to give polynomial time solutions to hard computational problems such as 3-SAT and k-colorability problems. Jonoska et al. have proposed studying self-assembly of graphs topologically, considering the boundary components of their thickened graphs, which allows for reading the solutions to computational problems through reporter strands. We discuss weighting algorithms and consider applications of self-assembly of graphs and the boundary components of their thickened graphs to problems involving minimal weight Eulerian walks such as the Chinese Postman Problem and the Windy Postman Problem

Migration systems, pioneers and the role of agency

The notion of a migration system is often invoked but it is rarely clearly defined or conceptualized. De Haas has recently provided a powerful critique of the current literature highlighting some important flaws that recur through it. In particular, migration systems tend to be identified as fully formed entities, and there is no theorization as to how they come into being. Moreover, there is no explanation of how they change in time, in particular how they come to decline. The inner workings – the mechanics – which drive such changes are not examined. Such critiques of migration systems relate to wider critiques of the concept of systems in the broader social science literature, where they are often presented as black boxes in which human agency is largely excluded. The challenge is how to theorize the mechanics by which the actions of people at one time contribute to the emergence of systemic linkages at a later time. This paper focuses on the genesis of migration systems and the notion of pioneer migration. It draws attention both to the role of particular individuals, the pioneers, and also the more general activity of pioneering which is undertaken by many migrants. By disentangling different aspects of agency, it is possible to develop hypotheses about how the emergence of migrations systems is related to the nature of the agency exercised by different pioneers or pioneering activities in different contexts.migration systems, agency, emergence, pioneer migrants, migrant networks, social capital

Sustainable technology and land use controls : a study of the effects of subdivision regulations and zoning on the adoption of sustainable technology and practices

The purpose of this thesis is to examine the impacts of subdivision regulations and local government policies on the adoption of sustainable technologies and design practices in Knoxville, Tennessee. Case studies were conducted on three subdivisions, each marketed towards a different income level. Land-use zoning, city subdivision regulations, subdivision covenants and subdivision by-laws were reviewed in this study. It was observed that all case studies had similar levels of restrictions placed on residential designs. The low-income case study had the newest zoning and incorporated the most sustainable practices into its regulations, in comparison with the·other two case studies. Overall, the evaluation concluded that in most cases sustainable technology and practices were not restricted. When a technology or practice was restricted, the placement of additional procedural hurdles was the most common form of restriction. Some regulations and polices did ban the use of some technologies or practices but only in very rare incidences

Humanizing Refugee Research in a Turbulent World

This essay adopts a critical perspective of the idea of humanizing refugee research. It argues that much social scientific research is intrinsically dehumanizing, as it simplifies and reduces human experience to categories and models that are amenable to analysis. Attempts to humanize research may productively challenge and unsettle powerful and dominant hegemonic structures that frame policy and research on forced migration. However, it may replace them with new research frameworks, now imbued authority as representing more authentic or real-life experiences. Rather than claiming the moral high ground of humanizing research, the more limited, and perhaps more honest, ambition should be to recognize the inevitable dehumanization embedded in refugee research and seek to dehumanize differently.Cet essai adopte une perspective critique à l’égard de l’idée d’humaniser la recherche sur les réfugiés. Il soutient qu’une grande partie de la recherche en sciences sociales est intrinsèquement déshumanisante en ce qu’elle simplifie et réduit l’expérience humaine à des catégories et des modèles se prêtant à l’analyse. Les tentatives d’humaniser la recherche peuvent efficacement remettre en question et déstabiliser les structures hégémoniques puissantes et dominantes qui encadrent les politiques publiques et la recherche sur la migration forcée. Par contre, elle pourrait les remplacer par de nouveaux cadres de recherche, désormais imprégnés d’autorité comme représentant des expériences plus authentiques ou plus proches de réalités vécues. Plutôt que de revendiquer une position de supériorité morale en humanisant la recherche, une ambition plus restreinte, et peut-être plus honnête, serait de reconnaître que la déshumanisation est inévitable dans la recherche sur les réfugiés et de chercher à déshumaniser autrement