VictorJuiz/thesis huggingface dataset:
Social Cohesion Analysis of Networks: A Novel Method for Identifying Cohesive Subgroups in Social Hypertext
Keywords: cohesive subgroups
social network
social network analysis
hierarchical clustering
centrality
similarity analysis
social hypertext

Finding subgroups within social networks is important for understanding and possibly influencing the formation and evolution of online communities. This thesis addresses the problem of finding cohesive subgroups within social networks inferred from online interactions. The dissertation begins with a review of relevant literature and identifies existing methods for finding cohesive subgroups. This is followed by the introduction of the SCAN method for identifying subgroups in online interaction. The SCAN (Social Cohesion Analysis of Networks) methodology involves three steps: selecting the possible members (Select), collecting those members into possible subgroups (Collect) and choosing the cohesive subgroups over time (Choose). Social network analysis, clustering and partitioning, and similarity measurement are then used to implement each of the steps. Two further case studies are presented, one involving the TorCamp Google group and the other involving YouTube vaccination videos, to demonstrate how the methodology works in practice. Behavioural measures of Sense of Community and the Social Network Questionnaire are correlated with the SCAN method to demonstrate that the SCAN approach can find meaningful subgroups. Additional empirical findings are reported. Betweenness centrality appears to be a useful filter for screening potential subgroup members, and members of cohesive subgroups have stronger community membership and influence than others. Subgroups identified using weighted average hierarchical clustering are consistent with the subgroups identified using the more computationally expensive k-plex analysis. The value of similarity measurement in assessing subgroup cohesion over time is demonstrated, and possible problems with the use of Q modularity to identify cohesive subgroups are noted. Applications of this research to marketing, expertise location, and information search are also discussed.
Amplified Photochemistry with Slow Photons
Keywords: slow photons
photochemistry
photonic crystal

Slow photon, or light with reduced group velocity, is a unique phenomenon found in photonic crystals that theoreticians have long suggested to be invaluable for increasing the efficiency of light-driven processes. This thesis demonstrates experimentally the feasibility of using slow photons to optically amplify photochemistry of both organic and inorganic systems. The effect of photonic properties on organic photochemistry was investigated by tracing out the wavelength-dependent rate of photoisomerization of azobenzene anchored on silica opals. The application of slow photons to inorganic photochemical processes was realized by molding nanocrystalline titania into an inverse opal structure and investigating its photodegradation efficiency in relation to the photonic properties. Changes in the photodegradation efficiency were directly linked to modifications of the electronic band gap absorption as a result of the photonic properties. The highest enhancement of twofold was achieved when the energy of the slow photons overlaps with the electronic band gap absorption, such that the loss of light due to photonic stop-band reflection was significantly reduced. In addition, the strength of slow-photon amplification with respect to the macroscopic structural order was studied by introducing controlled disorder via the incorporation of guest spheres into the opal templates. For the first time, a correlation between structural order, photonic properties and a photochemical process was established. The ability to combine slow-photon optical amplification with chemical enhancement was further achieved by incorporating platinum nanoparticles in inverse titania opals where the platinum nanoparticles increased the lifetimes of the higher population of electron-hole pairs arising from slow photon. Overall, various important factors governing the slow photon enhancement were investigated in detail, including the energy of the photonic stop band, angle dependence, thickness of the film, degree of structural order, filling fraction of the dielectric material and diffusion of a second medium if present. Theoretical calculations based on scalar-wave approximation in support of the experimental findings were provided wherever possible. The findings provide a blueprint for achieving optical amplification using slow photons in the broad range of photochemical or photophysical processes.
Diffractive Optics Near-field Laser Lithography for Fabrication of 3-dimensional Periodic Nanostructures
Keywords: Electronics and Electrical
Nano-fabrication
Laser fabrication
Photonic crystal
Laser material processing
Diffractive optical element
Optics
Photonics

The main objective of the present research work is to fabricate three dimensional photonic nanostructures in photo-sensitive polymers using a novel diffractive optical element (DOE) based lithography technique. A diffractive optical element is a promising alternative device for 3D fabrication where one DOE creates multiple laser beams in various diffraction orders that are inherently phase-locked and stable for reproducible creation of 3D near-field diffraction patterns from a single laser beam. These near-field patterns are captured inside a photosensitive material like photoresist to fabricate 3D photonic crystal templates. We have demonstrated fabrication of a wide range of 3D structures having different crystal symmetries and different relative crystal axis ratios. The present work has provided 3D photonic crystal nanostructures with uniform optical and structural properties over large sample area (~3-4 mm diameter) and through large 15-50 micron thickness with large number of layers (> 40) having period 550 nm - 650 nm and feature sizes between 200 nm and 300 nm. The short exposure time and small number of process steps shows promise for scaling to very large volume fabrication, dramatically improving the throughput, quality and structural uniformity of 3D periodic nanostructures, especially over that provided by tedious and costly semiconductor processing technology. The diffractive optics lithography is a parallel processing method that is easily scalable to generate centimeter-scale 3D nanostructures having large number of layers in several seconds. Due to low refractive index contrasts these polymer templates possess partial stopgaps along several crystallographic directions which can be practically used in several device or sensor applications where complete bandgap is not necessary. The potential usefulness of these partial stopbands for refractive index sensing of liquids has been demonstrated. These low refractive index polymer structures have been inverted with amorphous silica to convert a "soft" polymer structure to a robust "hard" structure. Further, few preliminary tests were done in fabricating 3D nanostructures into micro-fluidic channels for potential chromatography applications. The practical merits of this 3D fabrication technique will enable new practical manufacturing methods for optical and MEMS applications of 3D micro and nano structures.
School Choice, Competition, and Public School Performance
Keywords: School choice
Competition
School performance
Productivity

Reforms that expand school choice have been the focus of considerable policy interest, not least as a possible means of improving public school performance. According to the standard argument, increased choice will intensify competition, forcing public schools to improve quality in order to retain enrolment. Yet in principle, increased choice need not always raise performance, pointing to the need for careful empirical analysis. A key challenge in measuring the effects of greater choice on school performance is that convincing variation in choice is often hard to come by, especially in cross-sectional studies. And while school choice policy experiments have the advantage that choice increases in a clear way, few large-scale school choice policies have been implemented in North America. An important exception is the 2002 Ontario tuition tax credit, which eased access to private schools throughout Canada's most populous province. Analyzing the effects of the tax credit reform provides the focus of this thesis. The thesis begins by presenting the literature and gaps in existing research. The next chapter presents a model to clarify the link between increases in competition and school performance, and to motivate the empirical identification strategy. To set the stage for the main empirical analysis, I also provide some relevant institutional background relating to the Ontario education policy environment and the Ontario tuition tax credit as well as a descriptive analysis on the Ontario private school market. I then present an initial examination of the possible performance effects of the Ontario tuition tax credit using a difference-in-differences setup, before turning to the main empirical analysis, which exploits the differential competitive effects for public schools in districts with relative to those without a significant private school presence. The empirical results indicate that public school performance improved for schools facing the greatest competitive pressures following the introduction of the policy, controlling for a host of other relevant factors. To assess whether the effect is due primarily to increases in productivity, the analysis controls carefully for a series of alternative mechanisms. Overall, the Ontario findings are consistent with increased choice giving rise to productivity improvements in public schools.
Making the Invisible Visible: Public Library Reference Service as Epistemic Practice
Keywords: public libraries
epistemic practice
reference service
ethnographic
knowledge
case study

Public library services are evolving in response to the changing informational needs and behaviours of the citizens of the knowledge society. Reference statistics are declining and the move to self-service, virtual reference and an increasing use of mediating information and communication technologies calls into question the ongoing role of human, face-to-face information interaction at the public library’s front-line reference “desk”. An ethnographic case study of face-to-face adult reference service was conducted in a large Canadian urban public library. Over 8 months during 2006, a pilot study was conducted, followed by 170 hours of observations at the reference desks in three branch libraries of varying sizes and semi-structured interviews with front-line reference staff, library managers and reference service clients. 480 reference interactions were documented and policy documents were reviewed. An inductive staged process of analytical abstraction, a narrative approach to the interpretations and a critical reflexivity as participant researcher were employed. The main contribution of this study is the articulation of a practice framework for understanding and studying the reference service within the public library as organization. Sharing knowledge, finding meaning and learning are the outcomes of this epistemic practice. A typology of four reference encounters characterized in three dimensions of interpersonal communication; information exchange and mode of practice is detailed. This study challenges previous interpretations of reference services as a transactional, unitized question-answer activity and depicts it in a larger context as an interactional, relational set of activities that altogether characterize an epistemic practice. The three dimensions of structure (library organization), agency (reference staff and clients) and objects (library collections) anchor this conceptual framework – they are interdependent dimensions interacting to illuminate a robust understanding of face-to-face reference service. This study responds to previous research in which the reference process is studied separately from its social practice and its structural-organizational contexts.
Digesting the Third: Reconfiguring Binaries in Shakespeare and Early Modern Thought
Keywords: Shakespeare
Richard III
Troilus and Cressida
Coriolanus
critical theory
philosophy
Montaigne
Wittgenstein
scepticism

My argument assesses and reconfigures binary structures in Shakespeare’s plays and in Shakespeare criticism. I contend that ideas in early modern literature often exhibit three aspects, but that critics, who mostly rely upon a binary philosophical vocabulary, tend to notice only two aspects at a time, thereby “digesting” the third. My opening chapter theorizes the superimposition of triadic structures upon dyads, arguing that this new polyrhythmic strategy helps recapture an early modern philosophical perspective by circumventing the entrenched binary categories we have inherited from the Enlightenment. In Chapter Two, I examine the relationship of tyranny and conscience in Tudor politics, Reformed psychology, and Richard III. Early modern political theorists often employ a binary opposition of kingship and tyranny, and historians typically draw a binary distinction between absolutists and resisters. I argue that there were in fact three ideological positions on offer which these binaries misrepresent. As well, Reformed psychology emphasizes the relationship of the individual subject and an objective God, unmediated by community, and I propose that this opposition of subjectivity and objectivity digests the idea of intersubjectivity. In Richard III, Shakespeare interrogates the implausibility of Tudor political binaries and stages a nostalgia for intersubjective community and conscience. In Chapter Three I read the debates on value in Troilus and Cressida alongside contemporary economic writings by Gerard de Malynes on currency reform and “merchandizing exchange.” Our current models of value – intrinsic and extrinsic, use and exchange, worth and price – are emphatically binary, but the mercantile practices that Malynes describes depend upon a triadic conception of value. My contention is that Troilus and Cressida becomes a less problematic problem play when value is conceived as triadic rather than dyadic. In Chapter Four I explore early modern scepticism in connection with Coriolanus. Reading Montaigne and Wittgenstein in parallel, I distinguish between various conceptions of truth that are regularly grouped together under the blanket term “scepticism.” Then I turn to read Coriolanus as an experiment in competing modes of early modern epistemology, arguing that the play ultimately endorses the same sort of polyphonous Pyrrhonian scepticism that we find in Montaigne and Wittgenstein.
Characterization of CEACAM Binding by Human Specific Pathogens
Keywords: CEACAM
Pathogen

Human restricted pathogens such as Neisseria gonorrhoeae, Neisseria meningitidis, Moraxella catarrhalis and Haemophilus influenzae, as well as bacteria that are responsible for human specific disease, such as adherent-invasive and diffusely adhering E. coli, have evolved unique mechanisms to target and exploit host cellular CEACAM receptors during the course of infection. To gain further insight into how pathogens interact with CEACAMs, my studies have focused on understanding the molecular basis of bacterial attachment to CEACAMs by M. catarrhalis and N. gonorrhoeae. It is now evident M. catarrhalis and Neisseria sp. use two structurally and phylogenetically unrelated adhesins to bind CEACAMs on host cells; UspA1 and Opa proteins, respectively. In this thesis, I identify the sequence determinants for CEACAM binding in both Neisseria sp. Opa proteins and M. catarrhalis UspA1 proteins and show these sequences exist in distinct structural architectures within each adhesin, with the CEACAM binding regions in UspA1 existing in the context of an α-helical coiled coil structure while Opa sequences are localized to surface exposed loops that are presumably flexible in nature. I also highlight the functional diversity that exists with respect to CEACAM binding, within both the Opa and UspA protein families, a finding important in furthering our understanding of the role of CEACAM in bacterial infections. Finally, these studies show that sequences within Opa are sufficient for adherence to CEACAM, providing important insight into the development of CEACAM-specific therapeutics that have potential applications for a variety of distinct conditions ranging from autoimmunity to cancer.
Molecular Prediction of Patient Prognosis
Keywords: systems biology
prognostic markers

Each cancer is unique: it reflects the underlying genetic make-up of the patient and the stochastic mutational processes that occur within the tumour. This uniqueness suggests that each patient should receive a personalized type of therapy. Current predictions of a cancer patient’s outcome or prognosis are highly inaccurate. To aid in the prediction of patient prognosis based on highthroughput molecular datasets I have worked to optimize each step of the experimental pipeline: platform annotation, experimental design, consideration of tumour heterogeneity, data pre-processing and statistical analysis, and feature selection. First, a 12k CpG Island clone library was sequenced and annotated using a BLAT analysis. Second, microarrays built using this library were used in a fully-saturated study to evaluate the importance of ChIP-chip experimental design parameters. Third, intra-tumour heterogeneity was shown to influence specific pathways in a large fraction of genes. Fourth, a systematic empirical evaluation of 19,446 combinations of microarray analysis methods identified key steps of the analysis process and provided insight into their optimization. Finally, the combination of a two-stage experimental design and a novel semi-supervised algorithm yielded a six-gene, mRNA abundance-based classifier that could divide non-small cell lung cancer patients into two groups with significantly different outcomes in four independent validation cohorts. Further, a permutation study showed that millions of six-gene markers exist, but that ours ranked amongst the top 99.98% of all six-gene markers. The knowledge gained from these studies provides a key foundation for the development of personalized therapies for cancer patients.
The Effect of Mentoring on Leadership Self-efficacy in Nurses
Keywords: Mentoring
Self-efficacy
Leadership
Nurses

The literature suggests that mentoring is an important factor in the development of nurse leaders. Preliminary evidence suggests that self-efficacy may provide the conceptual link between receipt of mentoring functions and leadership performance. The purpose of this study was to contribute to the scientific knowledge base that informs nursing administration by examining the contribution of mentoring to development of leadership self-efficacy (LSE) among nurses. The conceptual framework that guided the study integrated theoretical perspectives from mentoring, leadership, and self-efficacy theories. A prospective, repeated measures design was used. One hundred Registered Nurses completed measures of LSE at the beginning and conclusion of leadership training and three months following training, and mentoring just prior to the final LSE measurement. Hierarchical regression analysis was used to assess the effect of mentoring on self-efficacy for each of five leadership practices. The change in LSE levels over the course of the leadership training intervention was included as a control for the effect of training. Participant administrative experience and professional education were included as controls. Study results did not support the proposition that protégé exposure to career and psychosocial mentoring would lead to higher levels of LSE. Mentorship did not predict self-efficacy for any of the leadership practices. The impact of participants’ mentoring experiences prior to the study, low statistical power due to a small sample size, homogeneity of respondents with respect to their mentorship experiences, and the possibility of a ceiling effect for LSE are possible explanations for these results. Results did suggest that mentored nurses were able to enhance their LSE during leadership training, and to sustain this increase upon return to their home organizations. Findings also provided insight into the prevalence of mentoring among nurses who are actively pursuing leadership development. Nearly two-thirds of the respondents were mentored during the study period, and these nurses reported that their mentoring relationships were active and positive. Mentoring continues to be advanced as an important contributor to leadership development among nurses. This study reinforces the need for further exploration of this relationship to inform and guide developmental interventions and allocation of resources.
Specters of "Isolationism"? Debating America's Place in the Global Arena, c.1965-1974
Keywords: Cold War
American Foreign Policy
Senate Foreign Relations Committee
Vietnam War
Foreign Aid
NATO

The United States emerged from the Second World War determined to play a leading role in the maintenance of international order. Increasing levels of tension between the United States and the forces of communism after 1945, however, slowly forced a redefinition of what might be more distinctly termed America's "global" responsibilities, such that by 1961 John F. Kennedy declared that the United States would "pay any price. . .in order to assure the survival and success of liberty." An identifiable Cold War consensus took shape based on the assumption that it was America's responsibility to lead, protect, and defend, the "free-world." Since America was effectively waging a battle to ensure the successful spread of its own values, the Cold War consensus also served to severely limit debate—dissent essentially implied disloyalty. By the mid-1960s, however, the Cold War consensus began to crack and a debate over American foreign policy began to emerge. That debate is the focus of this dissertation, which looks at the opposition to Cold War policies which emerged in the Senate, most notably among the members of the Senate Foreign Relations Committee --many of whom had once played a role in developing the very foreign policies they now protested. The war in Vietnam provided the focal point for much of the dissent, but the foreign aid program also became heavily criticized, as did America's NATO policy, particularly the size of the American military presence in Europe. More important, however, Senate dissenters came to question the United States' very position as the principle defender of the free world. They did not dispute the idea that America had a significant role to play in the global arena, but they did not believe that role should consist of being the world's policeman, the self-appointed arbiter of other’s affairs, and the keeper of the status quo. Because of their views, the so-called dissenters were labelled as "neo-isolationists." They saw themselves the true "internationalists," however, believing that the Cold War had led to confusion between internationalism and indiscriminate global involvement.