VictorJuiz/thesis huggingface dataset:
Node Selection in Cooperative Wireless Networks
Keywords: Cooperative Diversity
Spatial Diversity
Selection
Resource Allocation

In this thesis, we argue for node selection in cooperative decode-and-forward networks. In a single-hop network with multiple relays, we show that selecting a single node to aid in the transmission between a source and a destination outperforms both traditional orthogonal transmissions and distributed space-time codes. In networks where sources transmit information over multiple hops and relays can communicate with each other, we study the relationship between cooperation and channel-adaptive routing. We show that cooperation is only beneficial if designed jointly with a routing scheme. This motivates a search for optimal algorithms in generalized relay networks. In networks without restrictions on the relays in terms of whom they can communicate with, we study the problem of optimal resource allocation in terms of transmission time. The resource allocation selects the relays to participate in the transmission and optimally allocates time resource between the selected relays. To implement this resource allocation algorithm, we propose a recursive solution which reduces the computational complexity of the algorithm. For large networks, the resulting computational complexity of implementing the algorithm is exponential in the size of the network and is likely to preclude its implementation. We thus propose that the resource allocation be implemented sub-optimally through node selection: a subset of the nodes in the network should be selected and used as input to the optimal resource allocation algorithm. We provide guidelines for selecting the nodes and propose four heuristics which offer various complexity-performance trade-offs. Compared to the optimal resource algorithm, all four heuristics significantly decrease the required computation complexity of the optimal algorithm.
Communicable Disease Control in the New Millenium: A Qualitative Inquiry on the Legitimate Use of Restrictive Measures in an Era of Rights Consciousness
Keywords: Public Health
Ethics

Background: When Canadian public health officials issued thousands of quarantine orders during the SARS outbreak in 2003, it raised difficult questions about the legitimacy and acceptability of restrictive measures to achieve public health goals. While public health interventions have traditionally been justified on utilitarian grounds, this project aims to establish an empirical basis to justify public health action. The objectives are: 1) Descriptive: To describe the views of members of society on the justifiability of using restrictive measures to achieve public health goals; 2) Analytic: To analyze the use of restrictive measures at the intersection of public health policy, human rights norms, and ethics; and 3) Normative: To situate public health ethics within a Habermasian model of communicative ethics that can serve as the basis of justification for the legitimate use of restrictive measures based on the intersubjective recognition of public health and human rights. Methods: Individual interviews were conducted with 62 participants, including 23 health care providers, 16 members of the public, 13 community and/or spiritual leaders from the Greater Toronto Area, as well as six public health officials and four health care regulators at the local, provincial, and federal levels of jurisdiction. Findings: Participant views were analyzed and organized into themes that revolve around the following concepts: 1) common good; 2) types of quarantine; 3) compliance; 4) reciprocity; 5) uncertainty; and 6) communication. Conclusions: Combining empirical research with conceptual scholarship, it is argued that the recognition of and commitment to the common good by participants, which emerged as an overarching theme, provide justificatory power for the use of quarantine during communicable disease outbreaks. But to respect rights, while being committed to the common good, it is argued that we must move beyond the see-sawing between ostensibly competing requirements toward a conception that gives equal weight to public health and human rights; that is, both imperatives – the community and the individual – refer to one another without dissolving into one another. Following a Habermasian account of opening processes of decision-making to a moral-practical discourse, it is argued that public health ethics offers an important site for integrating his model of discourse ethics within public health deliberations to expand the scope of moral argumentation on--and ultimately to ground the justification of--the use of restrictive measures.
The Welcome Intrusions of TB Nurses. An Interpretive Phenomenological Study of Relational Work in Public Health Nursing
Keywords: nursing relationships
public health nursing
TB
nursing geography
surveillance
phenomenology

Nurse-client relationships are inherently valued in descriptions of the nature of public health practice and require consideration as intentional work that demands knowledge, skill, and personal engagement. They are also matters of place. In public health, they are largely taken-for-granted, particularly in the area of infectious diseases and the tuberculosis (TB) program specifically. TB nursing is structured within an explicit population focus, which challenges such relationship ideals as client-centered care, autonomy, and empowerment in everyday practice. This interpretive phenomenological study (Benner, 1994) of the relational work of TB nurses was undertaken to understand the nature of nurses’ relational work, wherever it happened, and how it was understood within the mix of assigned program tasks. Carried out in one of Canada’s largest TB programs, this study involved observing nine nurses and 24 clients in their respective visits over time, and interviewing 16 participants. Visits happened in homes and cars, and other assorted locations, highlighting how place shows up in these relationships and how nurses help clients to make sense of TB and broader life concerns shaping the experience of it. How they involve themselves interpersonally in these situations is the stuff that relational work is made of. Through the use of thematic analysis (Benner, 1994; Chesla, 1994), notes and transcripts were analyzed. The resulting interpretation of the nature of relational work is that of ‘welcome intrusions’, a notion that along with three key thematic dimensions: ‘getting through the door’, ‘doing TB but more than that’, and ‘beyond a professional’, addresses the central control-care tone of relational work. Together these themes identify key areas of knowledge and skill. That is, honesty and respect for privacy, ‘expertise’ in TB, dismantling the effects of stigma and displacement, and socializing-with-purpose. This emphasizes the value of articulating the everyday practices of nurses in population-focused programs that can contribute to successful treatment, and client healing and well-being. This relational work of TB nurses may be supported and enhanced when framed as the skill of involvement (Benner et al, 1996; Benner et al, 1999) and critically examined as part of providing comfort and enacting surveillance.
Microwave Devices and Antennas Based on Negative-refractive-index Transmission-line Metamaterials
Keywords: Negative Refractive Index
Metamaterial
Transmission line
Phase shifter
Balun
Power divider
Series-fed
Antenna
Array
Dipole array
Leaky-wave
Folded monopole

Several microwave devices and antennas that are based on negative-refractive-index transmission-line (NRI-TL) metamaterials are presented in this thesis, which exhibit superior performance features compared to their conventional counterparts. These are a Wilkinson balun, a 1:4 series power divider, a four-element printed dipole array, a leaky-wave antenna, and an electrically small folded-monopole antenna. The Wilkinson balun employs +90° and −90° NRI-TL metamaterial lines at the output branches of a Wilkinson divider, to achieve a six-fold increase in the measured differential output phase bandwidth compared to that of an analogous balun employing transmission lines, while occupying only 55% of the area. The 1:4 series power divider comprises four non-radiating 0° NRI-TL metamaterial lines, each with a compact length of λ0/8, to provide equal power split to all four output ports. Compared to a conventional series power divider employing one-wavelength long transmission lines, the metamaterial divider provides a 154% increase in the measured through-power bandwidth, while occupying only 54% of the area. The metamaterial series power dividing concept is also applied to a four-element fully-printed dipole array that is designed to radiate at broadside, in order to demonstrate that the array exhibits reduced beam squinting characteristics. It is shown that the metamaterial-fed array has a measured scan-angle bandwidth that is 173% greater than an array that is fed using a conventional low-pass loaded line. The reduced-beam squinting property that NRI-TL metamaterial lines offer is subsequently exploited to create a leaky-wave antenna that radiates a near-fixed beam in the forward +45° direction, with an average measured beam squint of only 0.031°/MHz. This is achieved by operating the antenna in the upper right-handed band where the phase and group velocities are the closest to the speed of light. Finally, an electrically small antenna comprising four 0° NRI-TL metamaterial unit cells is presented which supports a predominantly even-mode current, thus enabling it to be modeled as a multi-arm folded monopole. This significantly increases its radiation resistance, which allows it to be matched to 50 Ω, while maintaining a high measured efficiency of 70%.
Influence of the Quasi-biennial Oscillation on Interannual Variability in the Northern Hemisphere Winter Stratosphere
Keywords: Middle atmosphere dynamics
Quasi-biennial oscillation

Observations show that the interannual variability of the Northern Hemisphere (NH) extratropical winter stratosphere is strongly correlated with the quasi-biennial oscillation (QBO) of tropical stratospheric winds, particularly during early winter. Most current general circulation models (GCMs) do not exhibit a QBO and therefore do not represent this important mode of tropical-extratropical interaction. In this study we examine the QBO-extratropical correlation using a 150-year GCM simulation in which a QBO occurs. Since no external forcings or interannual variations in sea surface temperatures are imposed, the modelled tropical-extratropical interactions represent an internal mode of atmospheric variability. The QBO itself is spontaneously forced by a combination of resolved and parameterized waves. The effects of this QBO on the climatological mean state and its interannual variability are considered, both by comparison with a control simulation (also 150 years in length, but with no QBO) and by compositing winters according to the phase of the QBO. Careful attention is given to the definition of QBO phase. Comparisons of the model results with observations (reanalysis data) are also made. QBO-induced changes in the climatological state of the model are found to have high statistical significance above the tropopause. In the extratropical winter stratosphere, these mean-state changes arise predominantly from the influence of the QBO on the propagation and dissipation of planetary-scale waves. This behaviour is shown to depend on the seasonal cycle, which argues for the usefulness of considering tropical-extratropical interactions in a GCM context. QBO influence on the interannual variability of the extratropical winter stratosphere is also seasonal, and the tropical-extratropical interaction is sensitive to the phase alignment of the QBO with respect to the annual cycle. This phase alignment is strongly affected by the seasonality of QBO phase transitions, which - due to the QBO being spontaneously generated, rather than having an imposed period - is somewhat realistic in the model. This leads to fluctuations in the strength of the modelled tropical-extratropical interaction occurring on a decadal timescale as an internal mode of atmospheric variability.
Studies of Proteins that Regulate Melanin Synthesis and Distribution
Keywords: cell biology
melanin
pigmentation
RNAi
melanocyte
melanosome

Melanin is the major component of skin-, hair-, and eye pigmentation in mammals. Synthesis of melanin takes place in specialized organelles in melanocytes, called melanosomes. As melanosomes mature during pigment synthesis, they are transported towards the tips of dendrites in the melanocyte, and eventually transferred to neighbouring keratinocytes to distribute pigment throughout the skin. A large number of proteins regulate melanin synthesis and distribution. Over one hundred genes have been associated with coat colour mutations in mice, and many of these genes have also been identified in human pigmentation disorders. Other proteins involved in pigmentation are part of pathways that are not unique to pigmentation alone, such as the Ras/ERK pathway. In mouse B16 cells, cAMP stimulation leads to the upregulation of melanin synthesis and dendrite extension. However, cAMP also activates the Ras/ERK pathway in these cells, which, upon prolonged stimulation, leads to an inhibition of melanin synthesis and dendrite extension. Here I show that the protein CNrasGEF, which was previously identified in our lab, is responsible for cAMP-dependent Ras activation in B16 cells, and therefore a part of the negative regulatory pathway of melanogenesis. In order to find other proteins involved in pigmentation pathways, I have developed a method to detect melanosomes using Cellomics KineticScan (KSR) high-content image analysis. This system could potentially be used in a high-throughput RNA interference screen to identify proteins that affect melanosome formation or transport. However, in a pilot study it appeared that knockdown levels achieved upon transient transfection of knockdown constructs from a mouse shRNAmir library against selected targets were in many cases not sufficient to detect an effect on melanocytes, either by confocal microscopy, or by Cellomics KSR analysis. Further reduction of expression levels is necessary before this system can be scaled up to high-content/high-throughput identification of proteins involved in pigmentation.
Actin-perturbing Activity of Treponema denticola Major Outer Sheath Protein (Msp) and Stress Fiber Formation/Stabilization by a Novel Peptide Conjugate Deduced from the Msp Sequence
Keywords: Treponema denticola
Actin dynamics

The major outer sheath protein (Msp) is the most prominent surface antigen of the periodontal pathogen Treponema denticola. It mediates adhesion to extracellular matrix and dysregulation of cytoskeletal homeostasis of host cells. Disassembly of actin filaments and the coincident subcortical de novo synthesis of actin filaments in fibroblasts upon exposure to Msp were investigated with a barbed-end fluorescent labeling method. The functional impact of actin cytoskeleton disorganization was determined with a scratch wound migration assay in fibroblast monolayers and a videomicroscopy migration assay in neutrophils. Msp pretreatment had a significant inhibitory effect on the migration of the fibroblasts across a collagen substratum and inhibited the neutrophil chemotactic migration towards a chemoattractant. In a study originally aimed to find the biologically active domains of Msp that may perturb actin, short peptides were selected from the deduced and predicted surface exposed regions of Msp and investigated for their role in actin dynamics and cell motility. A novel BSA-conjugated peptide (P34BSA) was found serendipitously to induce stress fiber formation and stability in fibroblasts. This activity was found to be mediated by Rho activation and cofilin phosphorylation, which are important tandem signaling pathways in the regulation of a variety of actin-dependent cellular functions. P34BSA was internalized by the cells. Yet, a mechanistic study using low-temperature treatments and depletion of cholesterol with methyl-β-cyclodextrin (MβCD) revealed that P34BSA most likely induces actin stress fiber formation extracellularly through a Rho-dependent signaling pathway. P34BSA induced Rho activation via binding of guanosine nucleotide exchange factor p114RhoGEF to RhoA, one of many exchange factors that have been shown to play a role in activating Rho signaling. Pretreatment with P34BSA partially protected the fibroblasts against the actin-disrupting effects of cytochalasin D and latrunculin B, and the cells maintained most of their actin filaments. P34BSA treatment caused retardation of fibroblast migration on a collagen substratum. It also inhibited the chemotactic movement of neutrophils towards the chemoattractant fMLP. P34 may represent a novel amino acid sequence of a bacterial virulence protein that, when conjugated to BSA, can be used as a chemical reagent to investigate RhoA signaling pathways in host cells.
Clinical Trials and Treatment Outcomes of Edentulous PatientsTreated with Implant-supported Prosthesis
Keywords: Dental implants
Edentulous

Since their introduction, the use of endosseous implant for replacements of missing teeth has increased dramatically. To date, however, there is no evidence-based answer to the important clinical question: What implant-supported prosthesis designs provide the best outcomes? Cochrane systematic reviews have been used to critically assess scientific literature, to answer a wide array of questions. This approach was used to focus on implant-related treatment outcomes, including patient-based outcomes. Data showed that in most cases clinical and patient-mediated outcomes did not differ significantly from one another regardless of the prosthesis used. However, long-term prognosis of implant-supported overdentures using magnet attachments may produce inferior outcomes when compared to other attachments. In this dissertation it was shown that long-term results following immediate loading of endosseous implants with overdentures were successful based on biological and clinical parameters, cost to patient, and patient-based outcomes. Moreover, it was noted that well-designed clinical trials evaluating efficacy of immediate loading with fixed prostheses are uncommon. Furthermore, a parallel randomized controlled clinical trial focusing on this issue was carried out. In this trial, the author investigated the effects of immediate and delayed loading of implants with mandibular fixed prostheses. The implant-related outcomes underscore that even when implants are loaded during the healing period (i.e. immediate loading), successful osseointegration can be achieved and maintained. Patients’ satisfaction and oral health-related quality of life indicated that the two loading schemes addressed patient’s need equally.
Primary Care Reform: A Case Study of Ontario
Keywords: primary care reform
professional autonomy
neo-institutionalism
key elements
political
technical
primary care
primary health care
ontario
primary care reform models

This dissertation examines the factors that have the most significant impact on the pace of change in the primary care (PC) sector in Ontario. In Canada, there have been many attempts to improve the PC system through the introduction of a variety of primary care reform (PCR) models. Some say that there is insufficient movement in the PC sector and that it is in a policy gridlock. Others assert that substantial progress has been made and that transformational change is proceeding. This dissertation demonstrates that PCR – the movement from PC to some form of primary health care (PHC) – is multi-dimensional and complex. It identifies the multiple dimensions of PHC and demonstrates that each dimension has implications for the structural relationships between the state and the medical association in the PC sector in Ontario. The framework for this dissertation was derived from three bodies of literature: PC/PHC, neo-institutionalism and professional autonomy. The research design used involves qualitative and quantitative methods, including historical analysis, document analysis, key informant interviews and qualitative data. The case study of PCR in Ontario demonstrates that while there have been some changes in the methods of physician payment and in the organization and delivery of PC, the majority of PCR models have not fundamentally altered the underlying institutional and structural relationships that characterize the sector. This includes the profession’s ability to control the political, economic and clinical aspects of care. Thus, the PCR models that propose the greatest amount of reform – those that alter structural relationships between the state and the medical association in a manner that results in a significant impact on the balance of power in the PC sector- are less likely to be adopted by physicians. This dissertation corroborates that the PCR models that have the greatest impact on professional autonomy are those that remain at the margins of the health care system, whereas the models that have little or no impact on autonomy have been more readily adopted.
Digital Microfluidics for Integration of Lab-on-a-Chip Devices
Keywords: Digital microfluidics
electrowetting
Lab on a chip
droplet manipulation

Digital microfluidics is a new technology that permits manipulation of liquid droplets on an array of electrodes. Using this technology, nanoliter to microliter size droplets of different samples and reagents can be dispensed from reservoirs, moved, split, and merged together. Digital microfluidics is poised to become an important and useful tool for biomedical applications because of its capacity to precisely and automatically carry out sequential chemical reactions. In this thesis, a set of tools is presented to accelerate the integration of digital microfluidics into Lab-on-a-Chip platforms for a wide range of applications. An important contribution in this thesis is the development of three rapid prototyping techniques, including the use of laser printing to pattern flexible printed circuit board (PCB) substrates, to make the technology accessible and less expensive. Using these techniques, both digital and channel microfluidic devices can be produced in less than 30 minutes at a minimal cost. These rapid prototyping techniques led to a new method for manipulating liquid droplets on non-planar surfaces. The method, called All Terrain Droplet Actuation (ATDA), was used for several applications, including DNA enrichment by liquid-liquid extraction. ATDA has great potential for the integration of different physico-chemical environments on Lab-on-a-Chip devices. A second important contribution described herein is the development of a new microfluidic format, hybrid microfluidics, which combines digital and channel microfluidics on the same platform. The new hybrid device architecture was used to perform biological sample processing (e.g. enzymatic digestion and fluorescent labeling) followed by electrophoretic separation of the analytes. This new format will facilitate complete automation of Lab-on-a-Chip devices and will eliminate the need for extensive manual sample processing (e.g. pipetting) or expensive robotic stations. Finally, numerical modeling of droplet actuation on single-plate digital microfluidic devices, using electrodynamics, was used to evaluate the droplet actuation forces. Modeling results were verified experimentally using an innovative technique that estimates actuation forces based on resistive forces against droplet motion. The results suggested a list of design tips to produce better devices. It is hoped that the work presented in this thesis will help introduce digital microfluidics to many of the existing Lab-on-a-Chip applications and inspire the development of new ones.