title: PARTIALLY COHERENT PULSE PROPAGATION IN RESONANT LINEAR AND NONLINEAR MEDIA

subject:
Nonlinear optics
Linear Optics
Optical Coherence
Statistical Optics
Ultrashort Pulses
Optical Resonance

abstract:
Optical experiments reveal the fact that real laser pulses have random fluctuations in their
amplitude and phase that crucially affect pulse evolution. Statistical optics considers the
random nature of light to give a more realistic description of laser pulses behavior.
Generation of ultrashort pulses, operating at frequencies close to internal transition
frequencies of medium atoms, motivated the growing interest in studying on-resonance
light-matter interactions. Moreover, there exist optical phenomena that only occur at optical
resonance. Thus, near resonance light-matter interactions are of great importance.
In this dissertation, statistical properties of ultrashort pulses propagating in different
linear and nonlinear media near optical resonance is studied. Various partially coherent
pulses are simulated and effects of initial statistical properties of pulses on their propagation
in resonant absorbing and amplifying media are explored. The research performed
throughout this thesis leads to following results.
1- Various classes of ultrashort self-similar partially coherent pulses are explored along
with closed form expressions for their correlation functions. Also, the evolution of coherence
properties of pulses upon their short-distance and long-distance propagation is
investigated.
2- Generic partially coherent pulses are simulated and their global and local correlation
properties upon propagation in resonant linear absorber media are studied. The evolution of
the coherence functions of pulses shows that partially coherent pulses are strongly affected
by the medium regarding to their coherence levels. A correlation area theorem is also
derived to describe global correlation properties of stochastic pulses propagating in such
media.
3- Evolution of small-area pulse coherence properties, propagating in linear amplifiers
near optical resonance, is studied. Our simulation results reveal that more coherent pulses
are amplified more effectively by the medium than are their less coherent counterparts.
4- Propagation of partially coherent pulses in resonant, inhomogenously broadened
nonlinear media is simulated. Stochastic pulses of different coherence levels are generated
to investigate effects of initial properties of pulses on their long-term evolution. We also
provide evidence of self-induced transparency phenomena and soliton formation for relatively
coherent pulses. Also, evolution of the coherence functions reveal that low-coherence pulses lose their coherence level upon propagation faster than do highly coherent pulses.


title: PHOSPHORUS–BASED NEGATIVE ELECTRODES FOR SODIUM-ION BATTERIES

contributor:
Department of Chemistry
Master of Science
Dr. Mark Stradiotto
Dr. Peng Zhang
Dr. Jeff Dahn
Dr. Mark Obrovac
Not Applicable
Not Applicable
Not Applicable

subject:
SODIUM ION BATTERIES
NEGATIVE ELECTRODES

abstract: Sodium ion batteries are promising for future use in electrified vehicles and electrical power grids. However, there exist many challenges in the development of negative electrode materials. In this work, room temperature 119Sn Mössbauer spectroscopy and X-ray diffraction were used to study the sodiation mechanism of Sn4P3. The results suggest that upon sodiation, Sn and P begin to react with sodium simultaneously and different Na-Sn phases were formed. These findings are consistent with the behavior of Sn4P3 in Li cells. This study provides an example of how Mössbauer spectroscopy can provide insight into the mechanism of metal alloying reactions in metal ion cells. Five transition metal phosphides (M-P, M=Ti, Mn, Co, Cu, Zn) were synthesized and tested in sodium ion half-cell for use as negative electrode materials. The possibility of using transition metal phosphides as negative electrode was evaluated. Conversion reactions occur during the sodiation/desodiation of the materials. It was found that even though some transition metal phosphides offer high capacities, they all suffer from high irreversible capacity, poor cycling life and high voltage hysteresis. The effects of using different binders and operating temperatures were also explored.


title: Accelerometry: the key to measuring size-at-age and activity in fish

type: Thesis Thesis

contributor:
Department of Oceanography
Doctor of Philosophy
Dr. Emily Shepard
Dr. Daniel E Kelley
Dr. Michael Dowd
Dr. Dale Webber
Dr. Keith R Thompson
Dr. Christopher T Taggart
Received
Yes
Not Applicable

subject:
accelerometer
fish
swimming
behaviour
size-at-age
tag load
activity

abstract: Recent advancements in tracking technology have increased the ability to unravel key parameters affecting behaviour patterns among marine animals where direct observations are scarce. Within the suite of biologging techniques, tri-axial accelerometers are particularly promising for providing data that can link physiological and ecological processes in the context of movement. The objective of my thesis research was to determine how the analysis of accelerometer data can provide reliable and complex information on fish locomotion and behaviour that are relevant for advancing the informed management of commercially and recreationally valued fish. To reach this objective, a high-frequency accelerometer data logger was developed. Based on a series of controlled-environment and field experiments using this technology, a library of automated signal-processing algorithms was developed that relate acceleration signals to rates of activity, swimming speed, size-at-time and behavioural states in a variety of fish species. The algorithms are efficient in extracting behavioural states (feeding, escape, swimming) relevant to energy budgets as well as behaviour associated with spawning and courtship and parasite dislodging while being independent of animal size or tag placement. The most novel contribution is the development of a scaling relationship between tail beat frequency, speed and length in free-swimming fish that is based on accelerometer signal-processing techniques and early theoretical predictions. In the future, the technology and the models may provide valuable input for fish stock modelling by the in situ delivery of more reliable time series of length-at-age, and thus growth rate, in wild fish than that achieved using conventional techniques. Throughout this thesis, accelerometer data analyses challenge the assumption that movement data collected by accelerometer tags represent the normal behavioural repertoire of the tagged animal given low rates of tag sampling frequency currently employed as well as significant behavioural changes caused by tagging and handling stress as demonstrated by post-release fish behaviour modification observed in a field study. This thesis presents a significant contribution to the field through the development of an advanced accelerometer tag and processing algorithms that can be applied to many animal species to advance ecological and physiological theory.


title: Chemerin signalling in adipose tissue and intestinal homeostasis

contributor:
Department of Pharmacology
Doctor of Philosophy
Dr. Benjamin Tsang
Dr. Kishore Pasumarthi
Dr. Johan van Limbergen
Dr. James Fawcett
Dr. Christopher Sinal
Received
Yes
Yes

subject:
chemerin
adipokine
adipocyte
inflammatory bowel disease
microbiome

abstract:
Chemerin is an adipokine and potent chemoattractant for cells expressing chemokine-like receptor 1 (CMKLR1) which plays important roles in metabolism and immunity.  Chemerin is secreted as inactive prochemerin and undergoes extracellular processing to generate a variety of isoforms that range in bioactivity.  Clinical studies have demonstrated that chemerin levels are positively associated with obesity and inflammatory disorders.  However, the role of chemerin signalling in adipose tissue, and how elevated chemerin levels affect inflammatory disease progression, are poorly understood.  In this thesis, I describe the development of techniques to modulate levels of chemerin signalling.  I then investigate the role of chemerin signalling in three physiological contexts: mature adipocytes, pathogenesis of colitis, and intestinal microbiome composition.
Using a microarray-based approach, I identified matrix metalloproteinase (MMP)3 and several chemokines as novel targets of chemerin signalling in adipocytes.  Decreased chemerin levels resulted in increased MMP activity and macrophage migration towards adipocyte-conditioned media, via an NFkB-dependent mechanism.  This suggests that elevated chemerin levels with obesity influence adipose tissue remodelling.  Importantly, these effects were mediated through a unique adipocyte-processed chemerin isoform.
I next demonstrated that local expression, secretion, and processing of chemerin were positively associated with colonic inflammation in a colitis model. CMKLR1 knockout (KO) mice developed signs of clinical illness more slowly than wildtype, but ultimately developed similar levels of inflammation.  Intraperitoneal injection of bioactive chemerin had no effect on colitis severity, suggesting that local chemerin levels have a greater impact on the pathogenesis of colitis.
	Finally, I investigated differences in intestinal microbiome composition between wildtype, chemerin KO, and CMKLR1 KO mice.  Significant differences in Akkermansia and Prevotella abundance were observed in the absence of CMKLR1.  These bacterial populations are known to correlate with adiposity and glucose homeostasis, indicating that chemerin signalling might influence metabolic processes through modulation of microbiome composition.
Considered altogether, this work demonstrates that local chemerin signalling and processing plays autocrine/paracrine roles in adipose tissue and intestinal homeostasis.  Additionally, chemerin represents a novel biomarker in colon inflammation.  Modulation of local, context-specific chemerin signalling therefore represents a potential therapeutic target for the treatment of metabolic and inflammatory processes.


title: GAUSSIAN PROCESS PROXY MODELS  FOR  POROUS MEDIA FLOWS

contributor:
Department of Civil Engineering
Doctor of Philosophy
Jianbing Li
Hany H. El Naggar
Mo El-Hawary
Lei Liu
Dmitry Garagash
Mysore G. Satish
Not Applicable
Not Applicable
Not Applicable

subject: Gaussian Process Modeling

subject: Proxy/Surrogate Modeling

subject: Design of Experiment

subject: Porous Media Flows

subject: Parameter Estimation, History Matching, Inverse Process

subject: Blackbox Optimization

abstract: Despite the recent data explosion, many optimization and decision making processes are constrained with detailed and/or expensive simulation runs. Therefore, original simulation models are replaced with a light-weight model that captures the underlying input-output relationship plausibly nonlinear and complex, known as proxy. The focus of this study is to develop a Gaussian Process based proxy model and apply it to porous media flows. Porous media flows are ubiquitous and, the study of groundwater virus transport and petroleum reservoir flows, are crucial for health and economic impacts. Experimental design plays an important role in extracting the most information from limited data. Optimization is always required for selecting the best design. On the other hand ‘covariance function’ or ‘kernel’ is the most important ingredient for constructing a Gaussian process model. In this study, all these elements are carefully considered and new methods or modifications to the existing method(s) are proposed. A new and efficient method for experimental design is proposed. Modification to an existing heuristic optimization technique is also implemented to improve its performance. An algorithm is proposed to produce composite kernels, which can select the optimal kernel given some base kernels and the initial design. Eventually, the proposed methods are applied to different case studies. Parameters of 1-dimensional groundwater virus transport problem and the porosity of a small-size industrial reservoir are estimated successfully using a limited number of simulation runs. In the optimal well placement problem, despite limited data, optimal well locations were calculated for two production wells of a real reservoir. The locations predicted using proxy models were found to be reasonably close to the original well sites of the reservoir, validating the proposed proxy models.


title: Aspects of Singing Behaviour and Song perception in Two North American Forest Songbirds, Black-capped Chickadee (Poecile atricapillus) and Hermit Thrush (Catharus guttatus)

contributor: Department of Psychology and Neuroscience

subject:
birdsong
communication
recognition
conspecific
breeding
hermit thrush
black-capped chickadee

abstract:
Birdsong, used mainly by male songbirds, is centrally important to breeding behaviour as part of both territorial defense and mate attraction. Song perception is therefore important for both males and females, as they rely on song for conspecific recognition (identifying a singer as belonging to the same species) and individual recognition. Songbird species exhibit incredible variety not only with respect to song production, but also in terms of the acoustic features used for conspecific and individual recognition. Reflecting that variety, this thesis examined aspects of song production and conspecific recognition in two songbird species that differ greatly in terms of singing behaviour: the black-capped chickadee (Poecile atricapillus), a well-studied species with a single, simple song (fee bee), and the hermit thrush (Catharus guttatus), a less studied species in which individuals sing multiple versions of songs that are more structurally complex than those of the chickadee.
Previous behavioural work has shown that, for conspecific recognition, female chickadees attend to two relative pitch ratios within the fee bee song: the frequency ratio from the start to the end of the fee (the glissando) and the frequency ratio from the end of the fee to the start of the bee (the inter-note interval). In contrast, fieldwork suggests that males attend only to the glissando. In the first study, I measured the neural response of males and females to songs with those pitch ratios either intact or altered. The lack of differences in brain activity within NCM and CMM, auditory regions associated with discrimination of conspecific versus heterospecific vocalizations, with respect to playback type suggests that discrimination of such relatively subtle structural differences takes place elsewhere in the auditory system. Birds vocalized more to songs with the species-typical inter-note interval than to songs without it, and, in the operant study that followed, birds learned that discrimination with ease. In contrast, birds had difficulty learning to discriminate the presence or absence of the glissando, and their vocal responses did not differ when it was altered. This suggests, contrary to previous field work, that the glissando may not be necessary for conspecific recognition.
After an initial study to provide basic bioacoustics analyses of repertoire size, song structure, and song syntax in the little-studied hermit thrush, I examined geographic variation in song structure across the species’ large range. My studies describe extensive differences in frequency and temporal song characteristics, both between and within subspecies. I explored the implications of these differences in terms of conspecific recognition using a playback study where territorial males were exposed to local and foreign songs. Males exhibited a stronger territorial response to local songs, suggesting that they can discriminate local from foreign songs. These results are discussed in terms of recent findings that show extensive genetic divergence in the hermit thrush, suggestive of speciation. Taken together, these studies demonstrate the importance of acoustic features to conspecific recognition in two complimentary North American songbird species.


title: DEFINING A MULTI-PARAMETER OPTICS-BASED APPROACH FOR ESTIMATING CHLOROPHYLL A CONCENTRATION USING OCEAN GLIDERS

contributor:
Department of Oceanography
Master of Science
Dr. Dan Kelley
Dr. Michael Dowd
Dr. Christopher Algar
Dr. John Cullen
Dr. Marlon Lewis
Not Applicable
Not Applicable
Not Applicable

subject:
Chlorophyll a fluorescence
Ocean gliders

abstract: A bio-optical method for increasing the accuracy of chlorophyll a estimates from in situ fluorometers in the absence of traditional validation methods was implemented for autonomous gliders operating on the Scotian Shelf. The method generates a dynamic fluorescence-to-chlorophyll a conversion factor (F-factor) designed to account for bio-optical variability in the phytoplankton assemblage. Several changes were made to the method, allowing for the retention and analysis of depth-resolved information in the F-factor relationship. Trends in the F-factor with depth were driven by the bio-optical properties of the phytoplankton community, while horizontal trends were driven by the influence of coloured dissolved organic matter in the nearshore region of the study site. Variability in the F-factor within and between profiles introduced artifactual pattern into estimates of chlorophyll a, leading to a recommendation that the bio-optical method under investigation not be implemented for gliders on the Scotian Shelf.


title: Numerical Modeling of Salt Tectonics at Rifted Continental Margins

contributor:
Department of Earth Sciences
Doctor of Philosophy
Jurgen Adam
John Gosse
David Whipp
Grant Wach
Mark Deptuck
Nick Culshaw
Not Applicable
Yes
Yes

subject:
salt
salt tectonics
rifted margin
conjugate margin
numerical modeling

abstract: This thesis applies finite element numerical modeling to a range of projects investigating salt tectonics at rifted continental margins.  Both two-dimensional and fully three-dimensional models are used.  The first project demonstrates that incorrect density scaling in physical analogue models of salt tectonics leads to: 1) overestimated buoyancy force and 2) underestimated pressure gradient and sediment strength. Numerical models (2D) show a shift in salt structures, from diapir-minibasin pairs to expulsion rollover, when density scaling errors are corrected.  The second and third projects use 2D nested models, which allow for dynamic evolution of the continental margin scale system while providing high resolution visualization of salt basins, to study the interactions among syn-rift salt deposition and deformation, post-salt sedimentation, and ongoing rifting tectonics.  This work makes the important advancement of allowing salt basin geometry to evolve dynamically.  The second project considers intermediate width margins, and shows that the timing of salt deposition relative to rifting (early syn-rift vs late syn-rift salt) leads to distinct patterns of salt distribution and deformation.  Key features of salt tectonics at the Central Red Sea are captured using a layered salt succession deposited in the mid to late syn-rift period.  The third project considers wide continental margins, developed from weak continental crust.  In addition to studying syn-rift salt tectonics, the impact of sedimentation on the style of rifting is investigated.  A comparison is made to the central and northern Nova Scotia margin.  The final project presents preliminary results from a fully 3D numerical modeling study of the formation of minibasins through uneven sediment loading over salt.  This work compares the evolution of 2D-equivalent and fully 3D model designs, exploring the importance of studying even simple salt tectonic systems using a fully 3D approach.


title: ANTI-INFECTIVE EFFECTS OF FRUIT PHYTOCHEMICAL EXTRACTS AGAINST STREPTOCOCCUS PYOGENES

contributor:
Faculty of Agriculture
Master of Science
Dr. Dian Patterson
Dr. Song Lee
Dr. Bruce Rathgeber
Dr. Vasantha Rupasinghe
Not Applicable
Not Applicable
Not Applicable

subject:
Antibacterial
Streptococcus pyogenes
Berry extract

abstract: Group-A-streptococci (GAS) is the common cause of acute bacterial pharyngitis in children and adults. Streptococcal pharyngitis is initiated by successful colonization followed by establishment of biofilm. The aim of this research was to investigate the anti-infective, anti-biofilm, and anti-adhesion properties of aqueous and ethanolic extracts of ten selected fruits against Streptococcus pyogenes and its virulence factors. Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) for the six effective fruit extracts ranged from 0.25 to 4 mg/mL and 4 to 16 mg/mL, respectively. Minimum Biofilm Inhibitory Concentration (MBIC) and Minimum Biofilm Eradicating Concentration (MBEC) of cranberry and sumac berry extracts ranged from 1 to 2 mg/mL and 2 to 8 mg/mL, respectively. Minimum concentrations against the adhesion of GAS to uncoated and fibronectin coated substratum ranged from 0.25 to 16 mg/mL. Cranberry and sumac extracts possess notable inhibitory effects against growth, adhesion, biofilm formation and biofilm eradication of GAS.


title: A Graphical Processing Unit Based on Real Time System

contributor: Department of Electrical & Computer Engineering

subject:
Graphical Processing Unit
Real Time System
Image Processing

abstract:
The field of real-time image processing focuses on analysing and enhancing images in real time. An effective way to accomplish this is to utilise both the central processing unit (CPU) and the graphics processing unit (GPU) at the same time, to achieve the highest possible performance. The CPU manages tasks such as sequential operations and input-output, while the GPU is used for operations that can be done in parallel. The real-time processing of medical digital images requires the processing of an image with a response guaranteed within a specified time. This time period should be within a couple of seconds or less, so that images can be analysed and manipulated in a real-time medical scenario.
Real-time image processing has gained significance due to its widespread use in communication schemes involving video conferencing, video calls, innovative media, and digital and mobile cameras. Because of this, image identification has recently become an important research topic. The goal of this work is to develop a real-time digital image processing system aimed at feature identification and classification.
This thesis presents a method which seeks to reveal normal and malignant tissues. A method of digital image processing via real-time processing is designed to allow radiologists to detect abnormal tissues or cells, and then determine whether a tumor is a carcinoma or benign. Although radiologist decisions remain the preferred way of detecting non-palpable cancer, the method in this thesis aims to make detection by radiology trainers and radiologists easier and more accurate than is the case with traditional techniques.
The research described in this thesis involves a toolbox with a number of different filters, including classical high- and low-pass filters, as well as various novel morphological filtering tools. Edge and feature detection algorithms have also been added.
This thesis presents the first phase of the removal of noise from noisy images (having a signal-to-noise ratio of 10% or more). Simulated noise of different types is added to original images and then a variety of filters including mean, median, erosion, dilation, opening and closing filters are applied. These filters are used to denoise the original images. Erosion and dilation filters are the two basic filters in the area of mathematical morphology. Although they are usually used at the binary level, in the present research they are used at the grey-scale level. Mean and median filters function in a similar manner, except that median filters preserve more important details in a processed image than is the case with mean filters.
In addition to the above-mentioned filters, Laplacian filters are also utilised to increase the contrast of edges, and thresholding techniques are then applied for a first attempt at feature identification. Although the initial work was done in MATLAB, the algorithm developed here is also implemented using CUDA on graphics processing units, with the goal of implementing the system in real time or near real time. Moreover, some algorithms related to segmentation and automatic identification features have been developed in CUDA.


title: The importance of pricing: a microeconomic theory of multinational behaviour under trade barriers

abstract: This thesis develops a theoretical model of a multinational enterprise (MNE) consisting of two horizontally integrated firms, both monopolists in their own markets. The MNE is assumed to maximize total profits; hire labor and capital in competitive markets; own a scarce factor on which monopoly rents can be earned through trade; and price discriminate between countries. When cost and revenue differentials exist between firms profit maximization requires intrafirm trade, the direction and volume of trade reflecting these differentials. The value of trade depends upon the transfer price. The thesis discusses the effects of various transfer prices (average cost, marginal cost, fair market value) on factor and product markets; the welfare and efficiency gains from trade; the division of gains among producers, factors, consumers and governments; and the National Incomes and Balance of Payments of the host end home countries. The MNE's behaviour is studied under 1) free trade, 2) a tariff, 3) a profits tax by the home government, 4) taxation of MNE profits by both governments, 5) both taxes and tariffs. Chapter VII broadens the analysis to include vertically integrated multinationals and compares results. The main conclusion is that the theory of intrafirm trade differs from standard trade due to transfer pricing and joint profit maximization . As a result free trade may not maximize world welfare nor bring unambiguous gains to all parties. Tariffs can cause trade expansion and injure the import-competing industry with certain transfer prices. Corporate tax differentials are as much a barrier to free trade for the MNE as tariffs. A pure profits tax on a multinational monopolist is generally nonneutral since international tax neutrality requires equal actual tax rates or a special transfer pricing policy based on marginal export cost under free trade. The most neutral form of tax relief at present is the tax credit although internation equity can be affected even if tax neutrality is achieved. Tax policy is not impotent in a world of taxes and tariffs. Fair market value pricing may cause more distortions than marginal cost pricing. In short, transfer pricing and multinational intrafirm trade have important implications for governments, consumers, factors and producers that are only just being understood. This dissertation is one such attempt.


title: Characterizing Sources of Fecal Pollution at Four Urban Public Beaches in the Halifax Regional Municipality

contributor: Department of Process Engineering and Applied Science

abstract: Within the last few years several beaches in the Halifax Regional Municipality have closed frequently due to increased levels of E. coli within the beach waters. Enumeration, microbial enrichment, and genetic microbial source tracking methods were used to enumerate E. coli levels and detect the presence of select pathogens and host-specific fecal contamination markers within four local freshwater urban beaches. E. coli levels mostly remained below the maximum allowed concentration throughout the sampling season. Tested pathogen and fecal contamination markers displayed a low prevalence. E. coli levels were influenced by measured water quality parameters and were shown to fluctuate on a day-to-day basis. However, E. coli were unable to predict the presence of enteric pathogens or fecal contamination markers. The beaches do not appear to be heavily contaminated and should generally be safe for public use. The use of E. coli as a fecal indicator needs to be further assessed in future studies.


title: Patients' experience of occupational therapy discharge preparation

contributor:
School of Occupational Therapy
Master of Science
Jacinthe Savard
Heidy Lauckner
Mary Egan
Brenda Beagan
Received
Not Applicable
Not Applicable

subject:
discharge
patient experience
occupational therapy
client-centredness

abstract:
Discharge planning is intended to assist hospitalized patients returning home. Occupational therapists play an important role in interdisciplinary discharge planning by assisting with the identification of potential barriers to discharge and discussing possible strategies with clients, such as recommending equipment and/or additional support and offering other interventions that can facilitate return to home. A deeper understanding of patients’ perspectives of discharge preparations can be used to inform effective occupational therapy discharge interventions.
Using interpretive description, the experiences of 6 patients recently seen by an occupational therapist in preparation for discharge from acute care settings were explored in qualitative interviews. Results indicate that occupational therapy discharge preparation was perceived as valuable and client-centred by most participants. It was noted that past health care experiences, patient’s pre-existing personal values, beliefs and expectations of the health care system and families’ concerns all impacted the occupational therapy discharge process.


title: A Spectrum of Experience: Perspectives on Autism from Moshi, Tanzania

contributor: Department of Sociology & Social Anthropology

subject: autism disability neurodiversity Tanzania

abstract: There are two ways of viewing autism: as an affliction, or as an identity. The first, biomedical perspective is most common, but communities of self-advocates are lobbying for a more socio-cultural approach, arguing for the societal recognition and celebration of “neurodiversity.” The limited research on autism outside of a western context is almost exclusively epidemiological, assuming ignorance on the part of least developed countries in addressing issues of disability. This paper explores the lived experience of autism in Moshi, Tanzania through a 2.5 month multi-sited ethnographic study to identify and validate socio-cultural perspectives of autism and to determine whether a parallel concept to neurodiversity might exist, arguing that Tanzania’s lack of medical infrastructure and social supports may be advantageous in creating the conditions for acceptance of neurodiversity, and suggesting that this potential may be harnessed by increasing the visibility of autism through informal social channels such as media and religion.


title: Investigating Malt Inducing Premature Yeast Flocculation: Threshold and Stability

subject:
PYF
Premature Yeast Flocculation
Flocculation
Brewing
Quality

abstract:
Premature yeast flocculation (PYF) has proven to be troublesome for the malting and brewing
industries. It causes production difficulties and quality issues characterized by poor attenuation
and low yeast cell counts post-fermentation. These issues result in variability in fermentation and
flavor profiles. For this reason it is critical for brewers to assess their malts for PYF potential. To
test for PYF potential in malt, the industries rely on a variety of fermentation assays to indicate if
a sample has PYF potential. This study used a modified miniature fermentation assay to determine
if malt displays PYF potential and its associated threshold. In addition to traditional wort
preparation methods, a wash technique was used to extract the PYF factor for use with synthetic
wort. This modification to the assay eliminated the need for a controlled mashing device and
reduced the amount of fine adjustments of the wort pre-fermentation to reach target start values.
Control malt known to display no PYF attributes and PYF inducing malts were used in the study.
To further our understanding of the PYF factor the “PYF Solution” extracted using the wash
technique was subjected to various conditions pre-fermentation. The PYF Solution was mixed with
the synthetic wort with varying ratios from 0-100% of the PYF solution (mixed with distilled
water) to find the threshold at which PYF characteristics was displayed. The wort was treated with
a combination of pre-fermentation boiling (60, 90, 120 minutes), chilling at 5°C and Freezing at -
30°C to further our understanding of the how these conditions affect the PYF factor. The trials
were conducted using a 15 mL fermentation with a consistent temperature and pitch rate (21°C,
1.5 × 107 cells/mL). The change in absorbance and Plato was monitored throughout the
fermentations. The control malt had no significant (P>0.05) difference in absorbance and Plato
measurements from PYF inducing malt when the synthetic wort had <70% PYF solution. Synthetic
wort containing >70% PYF solution had significant (P<0.05) differences from the control malt for
both absorbance and Plato measurements. Boiling treatments alone did not produce significant
(P>0.05) differences in the trials. Boiling followed by chilling yielded the same results and did not
have significant changes (P>0.05) in fermentation characteristics. While most of the prefermentation
treatments did not create differences in fermentation characteristics, boiling wort for
>60 minutes and freezing before fermentation caused the >70% PYF solution to display the same
fermentation characteristics as the control (P>0.05). These findings show that the PYF inducing
factor may be susceptible to further processing. This thesis established two further findings. First,
that the factor causing PYF must meet a threshold before it affects fermentation characteristics.
Second, mashing the PYF-inducing grain may not be absolutely crucial for testing PYF potential
of malt.


title: DISCIPLINOLOGY: REPRESENTATIONS OF THE STRUCTURE OF SCIENCE AND THE HUMANITIES

contributor: Department of Computational Biology and Bioinformatics

subject:
Disciplinology
Structures of Knowledge
Wikipedia
Digital Humanities

abstract: Phylogenetic software and techniques from natural language processing can be applied to the analysis of the structure of academic disciplines. This is possible through a synchronic analysis based on comparisons of the conceptual apparatuses of disciplines, as they are represented in the terminological characteristics of representative discourses. This empirical approach enjoys a superior justificatory status to merely intuitive representations. Finally, this work helps place one of the oldest structuralist problems in the philosophy of science in the scientific context it deserves: ``How should we represent the relationship between disciplines?"


title: DIE TUGEND DER FLUCHTTIERE. DER TOD IN ROBINSONS BLAUES HAUS (2012)  VON ERNST AUGUSTIN

contributor:
Department of German
Master of Arts
Dr. Hans-Günther Schwarz
Dr. Thomas Curran
Dr. Fritz Heuer
Dr. Hans-Günther Schwarz
Not Applicable
Not Applicable
Not Applicable

subject:
Ernst Augustin
Death
German Contemporary Literature

abstract: The novels of the author Ernst Augustin (born 1927) immerse the reader in astoundingly fantastic worlds and pose the question: What is real? Augustin's oeuvre is considered among the most imaginative works of contemporary German literature. Augustin also enjoys the esteem of the contributors to the “Arts Section” of many national newspapers, and is praised by many other contemporary authors. Nonetheless, a systematic study of his work does not yet exist. Death emerges as a basic narrative, which is particularly prevalent in the recent novel Robinsons blaues Haus (2012). Therefore,  the focus of my research is the topic of death in all its variations: from mortal fear and fuga mortis to the longing for death. As a result, the following questions are posed: How are mortal fear and the longing for death connected? What roles do the flight motif and the changes of identity assume?


title: The Two-Photon Excitation Fluorescence (TPEF) Enhancement of Dipolar Organic Chromophores in Y Zeolites

contributor:
Department of Chemistry
Master of Science
Dr. Mark Stradiotto
Dr. Jean Burnell
Dr. Norman Schepp
Dr. Alex Speed
Dr. Fran Cozens
Not Applicable
Not Applicable
Not Applicable

subject:
Two-Photon Absorption
Zeolites

abstract:
Two-Photon Absorption (TPA) is a non-linear optical (NLO) process that involves simultaneous absorption of two photons.  Efficiency of two photon absorption by organic compounds is influenced by many different factors, including the nature of the surrounding environment (e.g. polarity).  In the present work, the influence of the constricting and highly polar environment of zeolites on two-photon absorption of incorporated nitrobenzoxadiazole (NBD) derivatives is investigated.
 Six different analogues of NBD chromophores consisting of unsubstituted, N-alkylated and N,N-dialkylated amines were investigated. All showed strong single photon fluorescence (either conventional or laser induced), and easily detected femtosecond laser two-photon induced fluorescence, both in solution and in zeolites.  The results show that the efficiency of two-photon induced fluorescence remained largely unaffected by solvent polarity for all of the NBD derivatives examined. However, the efficiency of two-photon induced fluorescence was substantially influenced by the zeolite environment, with some NBD derivatives showing almost a 10-fold increase.


title: Public Libraries and Search Engines

contributor: Master of Library and Information Studies

subject:
search engines
public libraries
visibility
search engine optimization
accessibility
Google
discoverability
online
internet

abstract: Although public libraries are dedicated to connecting people to information, the information resources offered by many Canadian libraries are currently inaccessible to search engine indexing robots, and thus effectively invisible to online searchers. This mixed-method study investigates factors that may be impacting the visibility of Canadian public library resources on search engines through semi-structured interviews with library staff in ten libraries across Canada. Quantitative data about each library’s website is used to provide a more complete picture of the current visibility of participating libraries. The study identifies attitudes, organizational factors, and technological factors that may be motivating, inhibiting, and enabling search engine visibility, and provides recommendations on how to address these factors. By delving into the underlying factors which may be affecting libraries’ progress on the issue, this study aims to help inform libraries’ decision-making processes and practices, as well as clarifying avenues for further research.


title: NEW PLA(Y)CES OF LEARNING AND EXCHANGE: A PROTOTYPE TOWARDS EDUCATIONAL SPACES FOR CHILDREN AND THEIR CAREGIVERS IN A MODERN CONTEXT

contributor:
Faculty of Architecture
Master of Architecture
Brian Carter
Sarah Bonnemaison
Roger Mullin
Diogo Burnay
Not Applicable
Not Applicable
Not Applicable

subject:
architecture
early years play centre
Halifax
design for children

abstract: Presently, there are lack of programs, services and indoor places in central Halifax for children (aged 0 – 6) and the caregivers who stay home with them.  This thesis proposes the design of two casual “soft play based” drop-in centres for families.  Each one is tested architecturally in different urban environments for different client groups.  In each case, a set of design strategies is introduced that address the unique maritime climatic and cultural conditions or the area.  Rooted in philosophies of early years pedagogy, they set up dynamic programmatic combinations that take into account the needs of children, but also consider the needs of adults.  Each example varies in scale and ambition and serves to build a prototype of possible interventions that introduce a typology as a strategy to inform and improve options for early years educational environments.


title: Crossing the Tracks: Imagining a New Approach to Urban Rail Yard Revitalization in North Winnipeg

contributor:
School of Architecture
Master of Architecture
Brian Carter
Sarah Bonnemaison
James Forren
Niall Savage
Not Applicable
Not Applicable
Not Applicable

subject:
rail yard
urban design
infill development
Winnipeg (Man.)
cultural hub

abstract: This thesis proposes an approach to urban rail yard revitalization that is counter to the typical model of infill development. The railroad that historically joined Canada together, and galvanized urban development across the Prairies, now often separates the local communities that fall in its path. Many approaches to rail yard redevelopment conceive of a new master-planned community that includes all required amenities. However, this thesis explores how former rail yard sites could become unique environments that stitch together previously divided neighbourhoods, and celebrate the cultural value of Canada’s railroad. Using Winnipeg as a case study, my approach involves three site strategies that focus on retaining and highlighting the main rail line, establishing new connections between the surrounding neighbourhoods, and opening the remaining land for public space and cultural events. These events could include travelling markets, festivals, and expositions that would travel across the country by train and stop at redeveloped rail yards already located in the centre of major cities.


title: THE STUDY OF SEVERAL PROTEINS SYNTHESIZED AT VARIOUS STAGES OF CHICK DEVELOPMENT

subject: Biochemistry

abstract:
A method was developed for the assay of very small quantities
of radioactively-labelled peptide chains of human hemoglobin based
upon the formation of complex with porcine haptoglobin, and subsequent
precipitation of the complex with antiserum to the haptoglobin.
Attempts to apply the method to a kinetic study of
synthesis of the globin chains of embryonic chick hemoglobins
in explanted chick blastodiscs were unsuccessful. Exploratory
studies indicated one of the reasons for this failure is probably
a relatively low affinity of the embryonic chick Hbs for porcine
haptoglobin. Although the plasma of 8 week old chicks contained
a haptoglobin, no evidence was obtained for the presence of this
protein in the circulation of the 10 day embryo and supporting
membranes.
Reports in the literature indicate that levels of aminolevulinate
synthetase enzyme present in individual chick blastodiscs
are sufficient for assay by highly sensitive radiochemical
methods. However activity was not detectable by the most
sensitive method of assay currently available and prior positive
observations reflect artefacts of the assay method used.
The course of development of serotonin N-acetyltransferase
activity in the chick pineal during development to 18 days post hatch had no appreciable effect upon the course of increase in activity. However, a diurnal cycle in levels of activity was observed with
birds examined at 16 days post hatch. Preliminary studies of
organ cultures of embryonic chick pineal gland indicate that the
developmental increase in serotonin N-acetyltransferase activity
is probably not induced solely in response to norepinephrine.


title: City Within A City: Revitalization Through Connectivity

contributor:
School of Architecture
Master of Architecture
Brian Carter
Sarah Bonnemaison
Austin Parsons
Cristina Verissimo
Not Applicable
Not Applicable
Not Applicable

subject:
Connectivity
Revitalization
Adaptive Reuse
Public Realm
City-Building

abstract: This thesis explores the transformation of Montreal's iconic Molson Brewery into a city-within-a-city through adaptive reuse and connectivity.

abstract:
This thesis seeks to revitalize the soon-to-be vacated, iconic Molson Brewery in Montreal.
In many instances, the development of the Molson Brewery mirrors that of its urban
context. Occupying a footprint roughly equivalent to 12 Montreal city blocks, the Brewery
is located in a post-industrial, fragmented neighborhood. The facility’s layout suggests
that it no longer runs as an efficient industrial facility as the brewery complex consists
of a fragmented, incoherent series of building elements, analogous to the neighborhood
in which it is located. Entrenched in the collective memory of Montrealers, the Molson
Brewery’s adaptive reuse strategy emphasizes the preservation of building elements
rather than demolition. The complex will be revitalized by connecting all building elements
to one another, transforming the complex into a city within a city.

This thesis will draw upon the theories of Team 10 to define a strategy for the buildingas-
city. The Brewery, seen as analogous to a city, will be sub-divided into constituent
districts, each incorporating a different but complimentary program, addressing the needs
of the surrounding neighborhood and city. Districts will be further sub-divided and linked
together by a hierarchy of unifying elements. The redevelopment will also be linked to the
city beyond. By introducing a system of hierarchy and connectivity to the Molson Brewery,
this thesis can become a case study for large scale urban redevelopment.


title: The Archescape : Seeking the Way Out from Within

contributor:
School of Architecture
Master of Architecture
Brian Carter
Sarah Bonnemaison
Catherine Venart
Cristina Verissimo
Not Applicable
Not Applicable
Yes

subject: Architecture Rome Escape Medieval

abstract:
This thesis investigates the archescape (Wallis de Vries, 2014) within the historical center of Rome. The term refers to the point of intersection where architecture meets escape. The primal need for escape from the city’s pressures traditionally suggests fleeing outward to its greater landscape indulging in the qualities of natural elements. Instead, by providing an opportunity to engage with natural features inside the city we then escape through the same structure we flee from.
	Within the city’s structure are to be found inhabitable fields of the medieval type and transit lines of its modern one. These lines fragment the spontaneous character of the medieval city, imposing a structure of vision and transparency, ironically leading to an unsustainable urban growth. Within the medieval type, flight lines (Wallis de Vries, 2014) can be explored to reach moments of evasion that are connected to the public urban sphere. The lines of flight introduce the archetype of the portico, serving as liaison from urban field to architectural room, the holder of elusive natural elements in the city.


title: PEOPLE MEET IN PUBLIC: SOCIAL INTERACTIONS IN THE VERTICAL CITY

contributor:
Faculty of Architecture
Master of Architecture
Brian Carter
Sarah Bonnemaison
Catherine Venart
Diogo Burnay
Not Applicable
Not Applicable
Not Applicable

subject:
public space
post office
civic

abstract:
Privatization, urbanization, and advancements in communication
technology and social media have contributed to social isolation
and the degradation of public space by removing the real-life
interactions and chance encounters, essential for producing
valuable offline social networks, from urban life. This trend is
exemplified by partnerships between private developers and the
city resulting in condo lobbies masquerading a public space. Post
offices are explored as an opportunity to capitalize on a declining
public building typology, with a history of communal use, in order
to retain them as public assets amid rampant development. The
appearance and strategic location of post offices evoke in our
collective memory a valuable notion of civic and public. Postal
Station K at Yonge & Eglinton in Toronto serves as a prototypical
site. Vertical connections are explored as a means to encourage
social interactions between multiple publics accessing the
building, by providing visual connections as well as conditions
that allow people to transcend typical social segregations that
may stunt life in public spaces. This thesis aims to negotiate
a symbiosis between latent public buildings and the forces of
urbanization through the conception of a new type of vertical
public space that catalyzes social interaction.


title: OPEN-PIT COAL MINING IN THE ELK VALLEY AND RESULTANT SELENIUM POLLUTION: AN EGOLOGICAL RISK ASSESSMENT OF TWO FUTURE ELK VALLEY COAL MINING OPERATIONS

subject:
selenium
ecological risk assessment
assessment
Elk Valley (BC)
sport fish
trout

abstract:
Coal mining in the Elk Valley, British Columbia is one of the area’s largest industries and is important to local economic development. However, many ecological impacts associated with coal mining are being observed including impacts on one of the area’s most valuable sport fish, westslope cutthroat trout (WCT). Selenium (Se) has been particularly of concern due to its ability to biomagnify in aquatic food chains and accumulate in the tissues and eggs of higher trophic species. This has resulted in significant decreases in WCT reproductive success in areas of the Elk and Fording Rivers and has caused species extirpations from areas abroad. There is concern over the development of future coal mining projects in the Elk Valley including the Baldy Ridge Extension (BRE) project, which is an extension of Elkview Operations (EVO), and the Coal Mountain Phase II (CMO2) project, which is an extension of the current Coal Mountain Operations (CMO).
In order to assess the potential ecological risks from these projects, an ecological risk assessment (ERA) was conducted to look at the potential Se loading and associated impacts on WCT. CMO2 has the potential to impact WCT due to its proximity to one of the largest WCT spawning grounds in the region. BRE has the potential to impact WCT populations due to its estimated large quantities of Se loading into Michel Creek and the Elk River. Both projects present significant risk to WCT populations. CMO2 was not estimated to load significant quantities of Se into nearby waterways and WCT populations near BRE are some of Elk Valley’s lowest. For these reasons, both projects are considered medium-risk projects and should be further evaluated before their approval and development.


title: Evaluating the Functional Trophic Level of the Global Aquaculture Sector

subject:
Aquaculture
Functional Trophic Level
Trophic Level Analysis
Compound Aquafeeds
Marine Capture Fisheries
Fish Meal
Fish Oil
Trophic Level
Food Security
Sustainability

abstract: Previous studies have characterized the average trophic level of aquatic animals in culture at national, regional or global scales. All of these prior analyses, however, have assumed that the trophic level of an animal in culture is identical to when feeding in the wild. While reasonable for filter feeding organisms, it may poorly represent the diets of farmed aquatic organisms. For these, an estimate of the animal’s functional trophic level is necessary. Building on previously unpublished work, this study pieces together the functional trophic level of all animals in culture globally from 1970 to 2013. The model combines country- and species- specific production data as reported by the Food and Agriculture Organization of the United Nations, with published data on the fraction of a cultured specie’s growth that is feed-based, the composition of that feed, and estimates of the trophic level of marine inputs to aquafeeds throughout the period of analysis. Results not only provide insight into which species in culture deviate most from their natural or wild trophic levels but also allow the examination of the relative dependencies and trajectories of aggregate dependence on terrestrial primary production via crop-based inputs and marine primary production based on fishery-sourced inputs. Results show that as the global aquaculture sector continues to increase in production it is reducing its dependency on marine-derived aquafeed components, which are rapidly being replaced by plant-based alternatives. This leads to the conclusion that the global aquaculture sector has recently seen a decrease in its energy consumption and has the potential to sustainably expand and contribute to global food security.


title: Can Constructed Wetlands be the Future of Wastewater Treatment?  A Policy Analysis Determining the Gaps Within Canadian Legislation

subject:
constructed wetlands
wastewater
municipalities
wastewater treatment
efficiency
policy analysis
legislation

abstract:
Treating wastewater is a vital resource for ensuring the health and safety of residents and the environment. With the constant advancements in society, Canada’s municipal wastewater system is continually being modified and updated to incorporate changes in technologies, water quality standards and policies.  The introduction of constructed wetlands in municipal wastewater treatment systems has been a new revolution to combat the conventional systems inefficiencies. A review of the current system is done to understand where constructed wetlands can be introduced.
The conclusion of this study will help to promote change in municipal wastewater systems and incorporate techniques that benefit residents as well as the environment.


title: Exploring Parents’ Perception of the Importance of Nature Exposure

creator:
Dumulon-Lauzière, Camille
Dumulon-Lauziere, Camille

subject:
Bioaffinity
nature exposure
Nature Deficit Disorder
Wild Child Forest School
Environmental Education

abstract: Research shows that children’s time spent in nature is decreasing which often causes behavioural problems (Louv, 2008). This issue has sometimes been associated with parents’ own lack of understanding of nature.  It has been found that if parents themselves don’t understand the importance or nature, or do not have a sense of bioaffinity (i.e. love of nature), then they are less likely to make choices that will expose their own children to nature (Strife & Downley, 2009). Using a case study approach, the goal of this study is to identify the influences that motivate and/or discourage parents from enrolling their children in the Wild Child Forest School program, an environmental education program with the goal of exposing children to nature. Further, this research aims to understand how parents perceive the importance of nature for their children’s development. This work will add to the growing body of knowledge on motivations for nature exposure; help to fill gaps in the present literature available about parents’ perception of nature; and to understand the barriers present, which discourage parents from exposing their children to nature.


title: Comparing Road Network Scaling Relations of Amalgamated and Non-Amalgamated Canadian Cities

subject:
Road Networks
Municipal Amalgamation
Urban Growth
Urban Development
Municipal Transportation

abstract: This study compares the size of the road networks in amalgamated and non-amalgamated cities. According to Bettencourt et al., cities road networks follow a power scaling relation. Rui Yikangs model for urban development suggests that polycentric cities road networks are expected to be less efficient than monocentric cities. By arguing that amalgamated cities develop as polycentric cities, while non-amalgamated cities do not, this study attempts to test, if there is any statistically significant difference between amalgamated and non-amalgamated cities road network scaling relations. The findings of this study show that amalgamated cities road networks are larger than their non-amalgamated counterparts, suggesting links between maintenance cost, and energy use for transportation.


title: Analysis of Mixed Models for Binary Longitudinal Data, with Application to Prescription Switching Patterns

contributor: Department of Mathematics & Statistics - Statistics Division

subject:
generalized linear mixed model
statin use pattern

abstract:
This thesis aims to study the statin use patterns of the Nova Scotia seniors population
and the patients’ adherence to medication by applying a generalized linear mixed
effect model (abbreviated as GLMM).
Observations for a single subject will include the initial prescription and the
sequence of transitions. The data can be modeled as short binary series, with tran-
sition probabilities allowed to vary by subject. In this thesis, 10 sets of parameter
values were run and the results were compared using tables and box plots. Mean
Squared Error (MSE) and Estimated Bias (EB) are calculated to measure how close
the estimated parameters are to the true values. For each parameter set, 10 and 100
simulations were run. We can make the conclusion that the generalized linear mixed
effect model works well in the application of medication use patterns and the two
separate GLMM models make sense.


title: An Estimation of the Rebound Effect in the Halifax Regional Municipality

subject:
energy efficiency
rebound effect
halifax regional municipality
energy consumption
efficiency improvements
elasticity of demand for energy
jevon's paradox
khazoom-brookes postulate
econometrics
residential

abstract: This paper analyzes the existing body of literature concerning the rebound effect, and attempts to synthesize region specific data about the rebound effect in the Halifax Regional Municipality. By using pre-existing econometric models, which are based on price elasticities, a preliminary estimation of the rebound effect has been found, at a value of -0.52. This value is slightly higher than the average estimations for the rebound effect, which suggest a value of -0.49. By applying this data to the total residential energy consumption in the Halifax Regional Municipality, the rebound effect can be found to have an impact of ~$2,100,000 CDN. Moving forward, it is recommended that energy efficiency programs include education of the rebound effect in order to try and limit its impact.


title: Illusion or Reality: Does adoption of a certified environmental management system fundamentally alter the environmental impacts of industry?

subject:
Environmental Management Systems
ISO 14001
Negative Externalities
Envrionmental Stewardship
Quantitative Analysis
Greenhouse Gas Emissions
Climate Change
Large-Emitting Alberta Companies

abstract: This thesis seeks to contribute to current literature surrounding the efficacy of certified environmental management systems (EMS) at reducing negative environmental externalities associated with industry. In response to the skepticism in existing scholarship that certified EMSs achieve concrete reductions in negative externalities, a multiple regression model is used to quantitatively analyze the relationship or lack there of between the presence of a certified EMS at an industrial facility and reductions in greenhouse gas (GHG) emissions. Specifically, this thesis examines the presence of the ISO 14001 EMS certification among the largest carbon emitting facilities in Alberta to determine whether its presence has a statistically significant correlation to a reduction in emissions. The results of the regression analysis determine that the presence of an ISO 14001 certified EMS does not lead to a reduction in GHG emissions amongst Alberta’s largest carbon emitters. This thesis recommends that fundamental changes be made to the ISO 14001 certifying process to ensure a robust approach to manage more complex environmental problems, namely climate change, is adopted.


title: Reading Afghanistan

contributor:
Department of English
Master of Arts
Dr. Michele Byers
Dr. Lyn Bennett
Dr. Jerry White
Dr. Alice Brittan
Not Applicable
Not Applicable
No

subject:
Afghanistan
Afghan Poetry
Literature about Afghanistan

abstract: Contemporary representations of Afghanistan tend to follow meandering streams of earlier thought, specifically Victorian notions of the country and its people that emerged as the result of Britain’s nineteenth-century military encounters with the country; a strong Orientalist impulse; recourse to earlier travel writing, itself strongly imbued with outdated ethnographic study; as well as reliance on well-worn stereotypes and synedoches. The thesis examines how Afghanistan has been represented to the Western world since the 9/11 terrorist attacks brought renewed attention to the country, including how the voices of Afghan women, largely unheard due to prevailing cultural norms, have been appropriated as part of Western representations of the country. The thesis also gives attention to contemporary Afghan poetry (in translation) so as to present Afghan perspectives. Such exploration underscores how little new thought has been generated by the Western world about Afghanistan, thus reinforcing notions of the country’s fundamental alterity.


title: What Do The People Say? A Thematic Analysis of Transit Related Comments from the Dalhousie University Annual Sustainability Commuter Surveys 2012-2015

subject: Accessibility

subject: Bus

subject: Shuttle

subject: Transit

subject: Frequency

subject: Transit

subject: Frequency

subject: Travel Distance

subject: Travel Time

subject: Weather

subject: Satisfaction

subject: Reliability

subject: Halifax - Transit

subject: HRM - Transit

subject: DalTRAC (Dalhousie Transportation Collaboratory)

subject: Office of Sustainability

subject: Dalhousie University

abstract: Each year the Office of Sustainability conducts an Annual Sustainability and Transportation Survey, where between 1200-1700 staff, students, and faculty fill out the survey. Qualitative questions have been used in these surveys in attempt to gather feedback on commuting issues, and to better understand the barriers and opportunities of Dalhousie commuters as it relates to using transit and other transportation modes. This research examines the identified themes present in qualitative comments made by Dalhousie staff, faculty, and students who participated in the surveys; attempts to fill the information gap regarding these barriers and opportunities, as well aid in understanding specific themes associated with commuters, and their experiences and attitudes towards commuting. Four years (2012-2015) of survey data questions from the Annual Sustainability and Transportation Surveys will be used for this study. The qualitative research method employed for this project is inductive line-by-line coding whereby each line can have more than one code. This study documented a variety of barriers and opportunities regarding accessibility, travel time and distance, weather, risk, satisfaction, and safety. These barriers included: lack of reliability and frequency of service, weather deterrents; while opportunities included: off-site parking with bus or shuttle options to and from campus locations, increased amount of weather protection barriers for waiting commuters, and routes to outside the peninsula (directly to and from Dalhousie campuses).


title: A Dynamic Approach for Visualizing Local and Global Information in Geo-spatial Network Visualizations

contributor:
Faculty of Computer Science
Master of Computer Science
Norbert Zeh
Sageev Oore
Alex Brodsky
Stephen Brooks
Not Applicable
Not Applicable
Not Applicable

subject:
Information visualization
Geo-spatial networks
Social networks
Layout manipulation
Time-series data visualization

abstract:
Geo-spatial network visualization is a fusion of visualization techniques and geographic information science, and has progressed rapidly in recent years. However, challenges still remain regarding the clarity of high density node-link graphs.

We present a dynamic approach for revealing the underlying information in locally cluttered areas while maintaining global edge trends around them, by creating and positioning multiple radial layouts within a geo-spatial connected graph. Moreover, two time series data-flow visualization approaches at both local and global scales are proposed respectively, namely: the peapod model and the hub model. The peapod model focuses on data flows within the local area while the hub model addresses the relations between groups of nodes across the graph. The approach is further refined by leveraging integrated circular layouts, stacked graphs, and word cloud techniques in several complementary views to support the exploration of categorical and aggregated data.

In addition to adhering to emergent design standards for geo-spatial visualization, the computational complexity and quantitative performance analysis on three different datasets were subsequently conducted to examine the scalability of the visualization model. The simulation results show that the main algorithms in our approach are able to achieve acceptable performance in real world test cases. Finally, our model's effectiveness are demonstrated by two significant case studies in different application fields, namely: US aero traffic network and GitHub collaboration graph. The case studies show that insightful knowledge can be discovered by the utilization of the dynamic approach and the support of various complementary features.


title: MECHANISMS OF COLONIZATION RESISTANCE TO SHIGELLA FLEXNERI

contributor:
Department of Microbiology & Immunology
Master of Science
Dr. Robert White
Dr. Brent Johnston
Dr. Song Lee
Dr. Morgan Langille
Dr. John Rohde
Received
Not Applicable
Not Applicable

subject:
shigella
colonization resistance
infectious disease
commensal microbiota
butyrate

abstract:
Shigella flexneri is an enteric bacterial pathogen responsible for shigellosis. Components of the commensal microbiota promote colonization resistance in mice and antibiotic treatment is required for susceptibility to S. flexneri infection. The mechanisms of resistance to colonization by S. flexneri have not been defined in the streptomycin-treated mouse model of infection. We hypothesize that a consortium of anaerobes cultured from healthy mice and serially passaged to select for streptomycin-resistant bacteria can confer protection against S. flexneri infection in streptomycin-treated mice. A close relative of Shigella, E. coli, uses nitrogen respiration to overcome colonization resistance in the streptomycin-treated mouse. We hypothesize that S. flexneri similarly uses nitrogen respiration to overcome colonization resistance and that a mutant for nitrate reductase activity is impaired in the ability to colonize streptomycin-treated mice. Intracellular carbon metabolism through the phosphotransacetylase-acetate kinase pathway has been demonstrated by S. flexneri during in vitro infection of cells in tissue culture. We hypothesize that this form of intracellular carbon metabolism also contributes to the ability of S. flexneri to colonize.
Consortia of commensal bacteria were cultured from healthy mice under selective conditions and characterized by 16S rRNA sequencing. Proton Nuclear Magnetic Resonance Spectroscopy was used to demonstrate the production of a short-chain fatty acid by the cultured bacteria that has previously been implicated in counteracting Shigella-mediated virulence. The cultured consortia of bacteria did not confer protection in the murine model of S. flexneri infection, but the selective culturing method repeatedly enriched for specific genera of bacteria and yielded 16S rRNA profiles distinct from the gut of the healthy mouse.
Nitrogen respiration and carbon metabolism pathways were investigated as potential mechanisms used by S. flexneri to promote colonization. The importance of the phosphotransacetylase-acetate kinase carbon metabolism pathway in intracellular proliferation of S. flexneri was confirmed in vitro, while nitrate reductase activity was dispensable for colonization of streptomycin-treated mice. By addressing the role of commensal bacteria, as well as nitrogen respiration and intracellular carbon metabolism, this work advances our understanding of the factors allowing colonization by S. flexneri and sets the stage for future study.


title: Deconstructing the Modern Research Paper: A Case Study Analyzing the Role of Values in Scientific-Decision Making

subject:
native species
non-native species
Chalker-Scott
modernism
post-modernism
Latour
Larson
Cockburn

abstract: My aim is to challenge the widespread notion among scientists that science is, or should be, the predominant basis for decision-making about natural resources and the environment. This misconception among researchers results in issues that begin with problem framing and continue along to data-gathering, as well as in the presentation of results. I will show that values should be the predominant basis for decision-making. The appropriate role for science is to provide insight into the potential consequences associated with decision alternatives. I will support these claims with an analysis of the scholarly literature on decision-making and demonstrate the issues through a case study in urban forest management literature. The case study will examine Chalker-Scott’s (2015) paper entitled “Nonnative, noninvasive woody species can enhance urban landscape biodiversity” as a demonstration of problematic claims about the role of science in resource and environmental decision-making.


title: AN EXPERIMENTAL STUDY ON COMPRESSED REPRESENTATIONS OF WEB GRAPHS AND SOCIAL NETWORKS BASED ON DENSE SUBGRAPH EXTRACTION

contributor:
Faculty of Computer Science
Master of Computer Science
Dr. Norbert Zeh
Dr. Peter Bodorik
Dr. Abdel-Aziz Farrag
Dr. Meng He
Not Applicable
Not Applicable
Not Applicable

abstract: The compressed web graph and social networks structures proposed by Hernandez and Navarro (Compressed representations for web and social graphs. Knowl. Inf. Syst. 40(2): 279-313 (2014)) support more queries than alternative approaches, including in-neighbor, out-neighbour, and mining queries. Their main strategy is to extract dense subgraphs from the given graph, and encode them using succinct data structures such as wavelet trees. Previous experimental studies on wavelet trees, however, test performance using textual data, which are drastically different from the data generated from web graphs. We thus engineer wavelet tree implementations for compressed web graph and social network structures. In particular, we propose a new wavelet tree encoding approach called combined encoding which can provide better time/space tradeoffs than previous approaches when used in Hernandez and Navarroa's framework to represent web graphs.


title: Depressive Symptoms and Sexual Health in University Students: The Role of Subscales in a Depression Screening Tool

contributor: Department of Community Health & Epidemiology

subject:
Depression
Sexual Health
Youth
Epidemiology
Factor Analysis
Cluster Analysis

abstract: Depressive symptoms have been shown to be associated with sexual risk-taking among young adults; however, whether this association is underpinned by specific types of depressive symptoms has not been examined. Using cross-sectional survey data from undergraduate students attending eight universities in the Maritime Provinces in Canada in 2012, I tested the associations between four depressive symptom subscales (i.e., Negative Affect, Anhedonia, Somatic Symptoms, and Interpersonal Problems) and various sexual risk behaviours (e.g., unprotected sex, having multiple partners) Depressive symptoms in general were associated with many forms of sexual risk-taking among female students, with the association being underpinned by the Anhedonia and Somatic Symptom subscales. There were few associations observed among male students, although Somatic Symptoms were associated with having multiple partners in the past year. Depressive symptom subgroups, established using cluster analysis, were defined entirely by symptom severity, and broadly replicated existing cut-points on the measure used. The findings of this study suggest that the often-observed association between depressive symptoms and sexual risk-taking is attributable to specific symptoms of depression, rather than the overall construct. This discovery has the potential to inform further research attempting to discern the mechanism underlying the association between depressive symptoms and sexual health.


title: Relationships of blood parameters and fertility-related traits with age and feed efficiency in young beef bulls

contributor:
Faculty of Agriculture
Master of Science
Dr. Dian L. Patterson
Dr. Mariana Diel de Amorim
Dr. Alan H. Fredeen
Dr. Yuri R. Montanholi
Received
Yes
Not Applicable

subject:
residual feed intake
scrotum thermography
semen quality
sexual development
triiodothyronine
testes ultrasonography
Bulls
Beef cattle--Breeding
Beef cattle--Feeding and feeds

abstract: Feed efficiency and bull fertility are two major factors affecting profitability of the beef industry. However, there is concern of an antagonistic relationship between these two factors, highlighting the need to clarify the relationship between age, feed efficiency and sexual development. Two experiments were undertaken to evaluate associations of blood parameters and fertility-related measures with age and feed efficiency in yearling bulls. Firstly, 32 bulls were studied and among other results, younger and efficient bulls exhibited lower testosterone and triiodothyronine levels, respectively. Secondly, investigation of 158 bulls revealed that younger bulls had smaller scrotal circumference, higher scrotal radiant heat loss and fewer normal sperm while efficient bulls indicated lower scrotal circumference, scrotal radiant heat loss, and a trend towards lower testicular echogenicity and higher sperm head defects. Metabolic differences associated with variation in feed efficiency may impact reproductive function as illustrated by features of delayed sexual development in efficient bulls.


title: Integration of Human Factors into Engineering Design

contributor:
Department of Mechanical Engineering
Master of Applied Science
Peter Allen
Darrel Doman
David Roach
Clifton Johnston
Received
Not Applicable
Not Applicable

subject:
Design
Engineering Design
Human Factors
Mechanical Engineering

abstract: Usability has been shown to increase the success of design projects, but is routinely left out of the design process. Through an investigation into the history and value of usability, experiential design project, analyzing the target users of commercially available products, and a case study into a successful project by novice designers, it was found that a tool would be helpful for guiding students to include human factors. This tool is in the form of an app, and prompts the students to incorporate usability from their initial research and project requirement development to the implementation and testing of their design. This tool will allow both educators and students to practice human-centred design to increase the usability and desirability of their design projects.


title: Phylogeographic Analysis of the Major Histocompatibility Complex Class II b Alleles of the Trinidadian Guppy, Poecilia reticulata

subject:
MHC alleles
Guppy
P. reticulata
Major Histocompatibility Complex
Trinidad
Trinidadian Guppy

abstract: The Major Histocompatibility Complex (MHC) are a set of vertebrae immune genes, that act in defense from cellular parasites. In Poecilia reticulata MHC is shown to also affect coloration and mate choice. The guppy acts as a model system in studying MHC. Having multiple copies of the MHC gene, large populations, and short generation time are ideal for studying MHC diversity. Samples were collected from Trinidad as Trinidad’s water system offers an ideal living lab with many genetically distinct populations separated by watersheds, waterfalls, and different predation levels. MHC may be separated into groups, known as super types, based on like binding properties of the peptide binding region. Through the construction of maximum likelihood trees super types were compared to the phylogeny of all alleles together. These trees were then aligned with the geography of Trinidad to look for correlation between clades of the tree and clusters of sample sites. When looking at the full tree of MHC alleles, significant correlation between phylogenetic tree and sample sites were found, however only super types 3, 4, 7, 10, and 14 were found to have this correlation. I discuss the role of selection, both natural and sexual on the presence and absence of MHC alleles, the roll of the Guppy’s colonization history in Trinidad, and the role of temporal separation due to the age of the MHC genes themselves.


title: TEMPORAL AND GEOGRAPHICAL VARIATION IN THE ATLANTIC USE OF INTRAVENOUS IMMUNOGLOBULIN: AN ECOLOGICAL STUDY FROM 2006-2007 TO 2013-2014.

subject:
IVIG
utilization
ecologic study
geographical variation
temporal variation

abstract:
BACKGROUND: The use of intravenous immunoglobulin (IVIG) has been increasing worldwide and in Canada. The high use of IVIG can partially be explained by the publically funded health care system in Canada, higher sensitivity for diagnosing immunodeficiency disease, absence of supply demand issues of blood products, and the use of IVIG for unlabeled indications. There are other causes for high use, and non-random variations point towards the presence of modifiable underlying explanations influencing utilization.  Although variation studies have been used to explore the utilization practices in other health disciplines, this type of research has never been done to study variations in the use of IVIG. This study measures the extent of geographical and temporal variations in the provincial age- and sex-adjusted rates of use of IVIG/1,000 (provincial rate) in the Atlantic provinces from 2006-2007 to 2013-2014, stratified by indications.
METHODS: Geographical and temporal variations are examined on the indirectly standardized rates using descriptive analyses, followed by statistical testing.
RESULTS: There are significant effects of each province and each fiscal year on the provincial rates (repeated measures analysis of variance, all p<0.0001). There are statistically significant increases in provincial rate, rates stratified by indications over time in each Atlantic province (Poisson regression, all p<0.0001). NL has the largest number of users of IVIG/1,000 and the largest mean annual usage of IVIG per patient. NL has the largest per capita number of hematologists (21/1,000,000) when compared with the other three Atlantic provinces. The rate of use in autoimmunity is the primary driver of provincial rates (ecologic graphic analysis).
CONCLUSION: There is significant temporal and geographical variation in provincial rates of IVIG use in the Atlantic provinces during 2006-2007 to 2013-2014. The emphasis of future research should be at reducing variations in the use of IVIG across Atlantic provinces by minimizing variations in physician related factors.


title: EFFECT OF 3D SIMULATED WELDING INDUCED HAZ, RESIDUAL STRESS AND DISTORTION FIELDS ON ULTIMATE STRENGTH OF ALUMINUM STIFFENED PLATES

contributor:
Department of Civil Engineering
Doctor of Philosophy
Sreekanta Das
Hany El Naggar
Dmitry Garagash
Neil Pegg
Yi Liu
Not Applicable
Not Applicable
Yes

subject:
welding
friction stir welding
metal inert gas welding
finite element analysis
buckling
ultimate strength
aluminum stiffened plates
ship hull

abstract:
A finite element study was conducted to investigate the friction stir welding (FSW) and metal inert gas welding (MIG) induced residual stresses, distortions and heat affected zone (HAZ) and their effects on the behaviour and strength of aluminum ship hull structures. A three-dimensional, two-step thermo-mechanical finite element model was developed to predict the residual stress and distortion fields as well as the heat affected zone for both welding methods. Following the verification of the model, the load vs. shortening curves of stiffened plates of varying geometries were obtained incorporating the welding induced imperfections from both welding methods. The load vs. shortening curves were then used to obtain the moment vs. curvature relationship for a modelled aluminum hull girder. The effect of stiffened plate geometry, and fabrication methods and associated welding induced imperfections on the behaviour, ultimate strength, and failure mode of stiffened plates as well as of the hull girder were presented and discussed.
For the welding induced imperfection study of two aluminum alloy 6061-T6 plates being welded together, results indicated that in comparison with the MIG welding, the FSW process resulted in up to 40% and 60% less tensile residual stresses and HAZ extent and negligible distortions. Increasing the clamping area in FSW process resulted in a decrease in the maximum tensile residual stress by 40%. For the load vs. shortening response study of tee-bar stiffened aluminum plates of various geometries, the result revealed that the presence of the residual stress and HAZ can reduce the ultimate strength of aluminum stiffened plates under the compressive loading by as much as 16.5% and 10%, respectively. The comparison of extruded stiffened plates welded by either FSW or MIG showed that the ultimate strength of the stiffened plates as affected by two welding methods was dependent on the plate slenderness. The higher magnitude of residual stress was shown to be beneficial for the ultimate strength of plates with high plate slenderness. For an ultimate strength study of a modelled hull girder, results showed that the model with extruded elements welded by FSW can have as much as 28% higher ultimate moment capacity than that with non-extruded elements welded by MIG welding. Within the models joined by MIG, the butt welding model resulted in 17% higher moment capacity than the fillet welding model.


title: DEVELOPING A NOVEL MODEL TO MEASURE DYNAMIC JOINT STIFFNESS OF L4/L5 JOINTS IN HUMAN LUMBAR SPINES USING AN INVERSE DYNAMIC APPROACH

contributor:
Department of Biomedical Engineering
Master of Applied Science
Dr. Derek Rutherford
Dr. Janie Astephen-Wilson
Dr. John Kozey
Dr. Janie Astephen-Wilson
Dr. Cheryl Kozey
Received
Not Applicable
Not Applicable

subject:
spine biomechanics
joint stiffness
dynamic stiffness
dynamic analysis

abstract: Joint stiffness has been claimed as the main component providing stability to human spines during different daily activities. As a result, researchers have developed various models to calculate spinal joint stiffness during performance of different functional tasks. However, to date, the models in the literature have estimated spinal joint stiffness using only discrete measures during dynamic tasks, and do not consider temporal changes. Therefore, the main objective of this thesis was to address this gap in the literature by developing equations to estimate dynamic L4/L5 joint stiffness in the sagittal plane, and to use these equations to estimate sagittal plane dynamic L4/L5 joint stiffness during two different controlled dynamic tasks under two different conditions (performing the tasks with and without abdominal hollowing (AH)). Ten healthy men between the age of 20 and 30 years old with no history of low back pain were recruited to perform two modified levels of Trunk Stability Test protocol (levels 1 and 3) with and without AH. The results of this study revealed that AH resulted in significantly (p < 0.05) higher dynamic L4/L5 joint stiffness and lower L4/L5 joint angle range of motion, but no significant effect on the sagittal plane L4/L5 joint moments.


title: Excess Pressure and Reservoir Compartmentalization in the Sable Subbasin, Offshore Nova Scotia

contributor:
Department of Earth Sciences
Master of Science
Dr. Richard Evoy
Dr. John Gosse
Dr. Nicholas Culshaw
Mr. Neil Watson
Dr. Grant Wach
Not Applicable
Yes
No

subject:
overpressure
excess pressure
reservoir connectivity
geocellular modelling
Sable Subbasin

abstract:
In the Sable Subbasin, pressure distribution in sediments is important from economic, environmental, and drilling safety perspectives; but it has not been consistently explained in the literature. Fluid pressures have been observed in Jurassic and Early Cretaceous reservoirs in over 200 wells and generally increase with depth in unexpected increments from hydrostatic pressure to immense excess pressure (approaching lithostatic gradient) - a system known as “stepped excess pressure”.
The pressure systems of the Scotian Margin were extensively studied from 1989 to 2003 by several researchers without reaching a consensus on mechanisms and timing of excess pressure generation and dissipation (Mudford and Best 1989; Wielens 2003; Williamson and Smyth 1992). Hydrocarbon generation during the Cretaceous was cited as a pressure source, supported by basin modelling results. Recent thermal modelling (South Venture O-59 well) suggests ongoing hydrocarbon generation (Wong et al. 2016).
In the Sable region, excess pressured sections are lithified with thin intra-formational seals, and high net-to-gross ratios of porous sandstone to tight sandstones, shales, and low permeability limestones. It is difficult to rationalize current excess pressure without late hydrocarbon generation (or another late pressure source) within the region given micro-nano Darcy flow across thin imperfect seals that should allow for pressure equilibration over hundreds of thousands to several million years.
In this study, the pressure distribution in the Sable Subbasin was investigated with a sub-regional 3D static reservoir model of the reservoirs associated for five gas fields: South Venture, Venture, Arcadia, Citnalta, and Uniacke. The model was built by interpreting 1520 km2 of 3D seismic data, that was integrated and calibrated with data from 27 wells. The model was populated with excess pressure data and lithologies interpreted from wireline logs and well tests, and inspected to test the hypothesis that excess pressure distribution is controlled by reservoir connectivity, which is ultimately controlled by permeability.
Pressure and fluids were interpreted to be currently entering the system by ongoing generation of hydrocarbons. At each of the fields, a similar arrangement of reservoir connectivity and pressure distribution were observed, although the ages of the rock units involved change from field to field due to progradational advance of the shelf and progressive formation of “expansion trends”. Expansion trends are isolated, high accommodation space depocentres formed in the hanging walls of down-to-basin listric faults, which formed as a results of depositional loading and salt movement at depth. These listric faults also set up low-relief, hanging wall, fault-bend folds - the principal hydrocarbon traps of the Subbasin. In the “deep” section, where reservoirs are stratigraphically and structurally isolated, the fluids and pressures are interpreted to be actively dissipating by mechanical leak. In the “intermediate” section, pressure equilibration within pressure cells occurs where the displacement of minor crestal faulting exceeds the thickness of minor intra-formational seals allowing for “stair stepping” up juxtaposed permeable units. In the “shallow” section, which is above the listric fault system, the reservoirs are contiguous and hydrostatically pressured.

abstract: In the Sable Subbasin, fluid pressures have been observed in Jurassic and Early Cretaceous reservoirs in over 200 wells and increase with depth in unexpected increments from hydrostatic to excess pressured. In this study, the pressure distribution in the Sable Subbasin was investigated with a geocellular model of the reservoirs in five gas fields. The model was built by interpreting 3D seismic data calibrated with wells, and populated with excess pressure and petrofacies. In the “deep” section, fluids and pressures are interpreted to be dissipating by mechanical leak. In the “intermediate” section, pressure equilibration within pressure cells occurs where displacement of minor crestal faulting exceeds the thickness of seals. In the “shallow” section, reservoirs are hydropressured. The distribution and dissipation of pressure in the Sable Subbasin is controlled by reservoir connectivity, which is dependent on permeability and a result of interplay between the regional structure, stratigraphy, diagenesis, and seal integrity.


title: STATISTICAL APPROACHES FOR MATCHING THE COMPONENTS OF COMPLEX MICROBIAL COMMUNITIES

subject:
BiomeNet
LASSO
NNLS
Jensen Shannon divergence

abstract: From protists to humans, all plants and animals live in close association with microbial organisms. These microbes are believed to play a critical role in a wide variety of settings, from globally significant nutrient cycling to influencing human physiology. The ecological community of commensal, symbiotic and pathogenic microorganisms that literally share the human body space have a profound effect on human health.

abstract: A hierarchical Bayesian model called BiomeNet can be used to identify the functional units of metabolic reactions, subnetworks and community-level metabolic networks. The framework models metabolic structures by assuming each sample consists of many tightly connected subnetworks, which in turn are comprised of di fferent reactions. When applying the method the number of subnetworks L must be pre-specified. When L is set larger in BiomeNet, the inferred structures of the subnetworks are expected to com out in a more trivial form. Three methods, LASSO, NNLS and a new method, MJSD, are applied to match a subnetwork in one analysis (say, when L=100) with several subnetworks when L is increased (say, when L=200). RSS and JSD are applied a matching criteria to conduct multiple tests to judge the significance of the matches. From the results, I am able to identify those "predominant" subnetworks and give a reasonable conjecture that those "predominant" subnetworks always come out as unbroken blocks for any larger L values.


title: Food Acculturation Pattern of International students in Halifax

subject:
Sociology
Food Studies
Education
Migration

abstract: Sociology and Social Anthropology Honours Theses

abstract: International students experience lots of food related challenges when they migrate from their home country to a new country. One such food related challenge international students in Halifax experience is dietary changes, due to the lack of availability of their cultural foods. Consequently, the aim of this study is to assess international students' food acculturation patterns in Halifax, in order to explore whether (un)availability of international students' cultural foods influences whether they maintain their culture of origin, conform to the culture of their host, or integrate within their host and home country's culture. A quantitative methodology is employed in this study, in order to examine the relationship between (un)availability of international students' cultural foods and the food acculturation pattern of international students in Halifax. The results of this study show that international students’ food acculturation patterns are dependent on the (un)availability of their cultural foods in Halifax. However, the experiences of (un)availability of cultural foods by international students are influenced by: the medium through which international students' cultural foods are available to them: in Halifax grocery stores, ethnic stores or ethnic restaurants in Halifax and where international students live in Halifax (either off-campus or on-campus). Factors that might influence the acculturation patterns of international students, based on the availability and accessibility of their cultural foods are gender and origin.


title: Connecting Anonymously: How Recovery is Represented Online

subject:
Critical health studies
Internet
Substance use
Sociology

abstract: This study explores how an online forum is used in recovery from addictive substance use. By doing a content analysis of the forum REDDITORSINRECOVERY, online supports were found to be helpful in providing a space to exchange knowledge based on personal experience. Anonymity was found to be important because it protected against the stigma associated with being a person who uses drugs.


title: “Oh, he’s gay!” The Perception of Gay Men of their Portrayal in Television and Film

subject:
Media studies
Gender studies
Sexuality
Social anthropology

abstract:
Currently, there is little research on the perception of gay men of their portrayals
on television and in film. Thus far, literature on such portrayals on the small and silver
screens has taken a general survey of men and women of all sexual orientations. This
qualitative research explores the perceptions of a group of gay men, as garnered in a
focus group, by presenting a curation of TV and movie clips to generate discussion. The
main findings suggest that shows and movies are apt to illustrate gay men as overly
sexual, flamboyant, and reliant on the act of ‘coming out’. The idea of ‘coming out’, as a
focus of the participants, was emphasized as an integral part of a gay man’s experience
and identity. Participants stressed the importance of recognizing one’s homosexuality, as
a practical act of saying the words – ‘I am gay’ – aloud, and they also highlighted the
perpetual process of coming out to everyone. Other findings in this research highlight
general stereotypes of gay men that establish a standard of ‘gayness’, which is advanced
through these media forms. This standard is utilized by both gay and straight individuals
as a reference for what it means to be gay – that is, what it looks and even sounds like to
be a gay man. In the case of heterosexual individuals, this research highlights that the
portrayal of gay men on television and in film can serve to condition how straight people
think about gay men in general. This standard of ‘gayness’, however, serves as a form of
role modeling that serves to inform gay youth how they should act. This anthropological
work is a glimpse into how gay men perceive their portrayals on TV and in film, but
further study is required to contribute to this very important topic.


title: Married to the Military: Employment Prospects for Civilian Female Spouses

subject:
Gender studies
Labour studies
Family studies
Sociology

abstract: The vast majority of research on the impact of military has considered the experiences of service members during and after their service. However, the impact of military lifestyle on civilian spousal employment is a relatively new topic of research. This research study considers the impacts that Canadian military lifestyle has on the employment prospects of civilian female spouses. Conducting semi-structured interviews, my aim is to consider how employment is affected, what impact childcare has on employment and to understand the perceptions that participants have of military support systems available to military families. Theories on the labour force participation of women and tied migration are instrumental in my analysis of the impacts of military lifestyle on women’s employment prospects. I conclude that systemic issues within military lifestyle and the labour force more generally have a negative impact on female spouse’s employment prospects. The impacts of childcare and other household responsibilities have an evidently negative impact on labour force participation as well. Support systems were used by military spouses for more traditional services, possibly reinforcing gendered divisions of labour.


title: ORTHOGONAL SIGNAL ALIGNMENT WITH VARIABLE RATE AND POWER IN MIMO Y CHANNELS

contributor: Department of Electrical & Computer Engineering

subject:
MIMO Y channels
signal alignment
Wireless networks

abstract:
The multiple-input multiple-output (MIMO) Y channel employs signal alignment (SA) to improve spectral efficiency of wireless networks. In this system of three nodes exchanging data via the relay, cooperation of terminals allows the data transfer of six messages in two phases, medium access control (MAC) and broadcast, each taking one time slot thus achieving up to three times the rate of the conventional
relaying system without SA. The antenna configuration in the original MIMO Y channel imposes limitations on controlling the minimum distance between signaling points representing network coded messages and this affects symbol error rate performance. To mitigate this problem, this thesis proposes to add one redundant antenna at every user and designs corresponding precoding vectors to obtain flexibility in the selection of orthogonal signaling dimensions and to simplify decoding at the relay. Additionally, the thesis develops adaptive power allocation and bit loading to optimize the system performance.