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Comparisons of ground-dwelling beetle assemblages in different stand types at Jack Haggerty Forest
Get PDFBeetles (Coleoptera) play an important role in Canada’s boreal forest as they aid
in many forest processes. Ground-dwelling beetles are the focus of this study, and most
of these beetles belong to the families Carabidae, Silphidae, and Staphylinidae, playing
a large role in the cycling of nutrients through predation and decomposition. The study’s
main objective is to determine if there is a difference in ground-dwelling beetle
assemblages under different stand types. This will be determined through the analysis
of species richness, species composition, and abundance under different stand types.
From the Jack Haggerty Forest in Thunder Bay Ontario, data was collected from
multiple stand types during the years 2022 and 2023 using pitfall traps. The data
collected was analyzed using generalized linear models and non-metric
multidimensional scaling through R statistical software. The results indicate that species
composition was not significantly different between sites or years. Species abundance
was significantly different in Pr60 compared to Pop45, Sb45 with Pr60, and Sb45 with
Sb100. Species richness was only significant on a stand level between Sb100 and
Pop45, Sb100 and Pr60, and finally, Sb100 and Sb45 were significantly different. The
study showed the importance of the preservation of multiple stand types in an area. This
idea should be implemented into forest management plans as it would increase the
forest's biodiversity and in turn health and resilience
Self-balancing five-level current source inverters
Get PDFFive-level current source inverters (CSIs) inherit the advantages including voltageboosting capability, absence of dv/dt issues, and reliable short-circuit protection, etc. In
addition, they have better harmonic performance compared to traditional three-level CSIs.
Many five-level CSI topologies have been proposed for various applications such as wind
energy conversion systems and high-power AC drives. However, traditional topologies,
using parallel structures of modules or inductors, suffer from a common issue: current
imbalance.
The main cause of current imbalance is the unequal on-state voltages of switching
devices, along with manufacturing tolerances and variations in the gating signal delays.
This imbalance can degrade AC output quality, and potentially lead to overcurrent
conditions that may damage components. The existing recommended solutions involve
closed-loop control, using additional current sensors to sample DC inductor currents and
adjust switching states accordingly. However, even the optimal approaches in the
literature have drawbacks, such as increased switching frequency, high computational
demands, and higher costs.
To address the issue of current imbalance, three novel topologies: X-, Γ-, and H-type
five-level CSIs have been proposed in this work. Unlike traditional five-level topologies,
the proposed CSIs achieve self-balance of the inductor currents without using additional
balancing control schemes. This reduces the complexity and cost of the system. New
SVM-based modulation schemes, designed for the proposed inverters, ensure good
harmonic performance and overvoltage clamping. Detailed analysis and calculations are
provided for their configurations, operating principles, self-balancing mechanisms,
modulation schemes, DC utilization, switch stresses, passive component sizes, and
overall efficiency. The performance of the proposed inverters is validated through both
simulations and lab-scaled experiments
Evaluation of multi-angle imaging with planar organ-targeted positron emission tomography detectors
Get PDFPositron Emission Tomography (PET) with 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (18F-FDG) is a functional imaging modality which is capable of detecting cancer tumors based on their increased metabolic activity – a fingerprint of cancer. This capability makes PET a key tool in oncology for cancer detection. PET imaging increasingly requires the visualization of specific organs with organ-targeted PET systems in response to the clinical need to enhance the diagnostic capabilities of PET imaging.
Organ-targeted PET detectors offer improved sensitivity and spatial resolution compared to conventional whole-body (WB) PET systems. However, ring-based organ-targeted PET detectors have a fixed diameter optimized for imaging a single organ, which limits their clinical utility. In contrast, planar PET detectors, consisting of two flat panels with adjustable separation, offer greater versatility for imaging multiple organs. However, planar PET detectors have limited angular coverage, which leads to image distortion (smearing) along the axis perpendicular to the detector plane. This smearing degrades the quality of 3D reconstructed images and reduces the accuracy of activity estimation in small lesions.
The objective of this Thesis is to improve the effective angular coverage of planar PET detectors by introducing detector rotations in a method called multi-angle image acquisition and reconstruction. Experiments were conducted using the Radialis PET camera, a planar organ-targeted PET detector designed for 2D breast cancer imaging. While Radialis organ-targeted PET technology significantly improves 2D visualization of breast lesions compared to traditional WB-PET systems, its 3D imaging capabilities are limited due to insufficient angular coverage.
The experiments with simulated, standard and custom-made phantoms filled with 18F-FDG solutions demonstrated that multi-angle acquisition and reconstruction improves image quality, eliminates image artifacts and provides more accurate quantitative estimates inside the phantoms, attributable to the increased effective angular coverage.
Overall, the findings of this Thesis suggest that multi-angle imaging with planar PET detectors can achieve full 3D reconstruction, broadening the potential for multi-organ imaging with planar organ-targeted PET systems
Exploring breeding season phenology of the Eastern Gray Treefrog (Dryophytes versicolor)
Get PDFAltered phenological cycles due to climate changes may affect species’ geographical
distributions as the new timing of important life-history events may allow species to
expand or shift their range. Insight into these processes can be gained through analyzing
relationships between environmental conditions and breeding phenology of the same
species at different latitudes. As climate change continues to impact species ranges,
especially in variable environments, exploring what influences breeding season will help
to understand ecosystem dynamics and how species can account for variable
environments. I analyzed how breeding season varies in timing and duration between the
northern range edge and range core of Dryophytes versicolor (Eastern Gray Treefrog,
Hylidae). I found that populations at the northern range edge had a significantly shorter
breeding season than the range core. This included a later onset of calling for the
northern range edge and an earlier end to the calling season. Populations at the northern
range edge also began calling at colder temperatures compared to those at the range core.
I explored life-history trade-offs within D. versicolor to understand if reproductive
investment may cause the end of breeding season. I analyzed the amount of mass lost by
D. versicolor males across a breeding season in relation to when calling ended. I found
that there was not a threshold mass loss in males that triggered the end of breeding
season. I did confirm the presence of a reproduction-survival trade-off, as males that
invested less the previous season were more likely to be recaptured in the following
season. There are multiple environmental and biological factors at play that determine the
timing of breeding season for D. versicolor. Further work would contribute to
understanding their life history and at what scale or severity they could be impacted by
future climate change
Do common over-the-counter antihistamine medications modify thermoregulatory responses during passive heat stress?
Get PDFOver the coming decade, climate change is expected to increase the duration and intensity
of pollen season and contribute to higher atmospheric concentrations of inhaled allergens
(Corden & Millington, 2001; D’Amato et al, 2015). This is likely to increase the number of
individuals who suffer from respiratory conditions such as allergic rhinitis (AR), worsen their
symptoms, and stress healthcare infrastructure (Beggs, 2004; Kim et al, 2018; Ziska & Caulfield,
2000; Ziska et al, 2019). Currently, guidance suggests all antihistamines may increase an
individuals’ risk of heat-related illness/injury (HRI) during heat stress by suppressing human
thermoeffector responses (Casa et al, 2015; Coco et al, 2016; OSHA, 2011; O’Connor &
DeGroot, 2024; Roberts et al, 2023; WHO, 2011). However, whether over-the-counter (OTC)
antihistamines for allergy, taken as recommended, alter sudomotor and/or cardiovascular
responses during heat stress has not been critically analyzed in humans. This thesis sought to
determine whether the oral ingestion of three common OTC antihistamines (diphenhydramine,
loratadine & desloratadine) would alter sudomotor, cardiovascular, or perceptual responses to
heat stress when compared to a placebo pill (sugar). A total of 10 young healthy participants
(5M, 5F, 22.6 ± 1.8 yrs, 174 ± 10 cm, 73.6 ± 10.8 kg) completed our double-blind randomized
crossover procedure where they consumed either i) 50 mg diphenhydramine ii) 10 mg loratadine
iii) 5 mg desloratadine or iv) a sugar pill before being passively heated to a mean body
temperature 1.5℃ above baseline. Preliminary data suggests that OTC antihistamines do not
alter local sweat rate of the forearm [Mg/cm2/min1 (Placebo (PLA): 0.411, diphenhydramine
(DPH): 0.436, loratadine (LOR): 0.368, desloratadine (DES): 0.432)], skin blood flow [%max
(DPH: 25.71, LOR: 21.81, DES: 21.10, PLA: 21.27)], heart rate [BPM (DPH: 72.25, LOR:
78.34, DES: 74.86, PLA: 74.94)], mean arterial pressure [Mm/Hg (DPH: 81.95, LOR: 82.09,
DES: 82.20, PLA: 80.98)], or rate-pressure product [Mm/Hg (DPH: 8604, LOR: 9051, DES:
9126, PLA: 8851)] during passive heating, suggesting they may continue to be a safe option to
allergic symptom management during periods of heat exposure. Further research aimed at
examining different OTC antihistamines and/or doses, in other heat-vulnerable groups and types
of heat stress is required to wholly conclude the HRI risk posed by OTC antihistamines
Intelligent algorithm based robust and fault tolerant control of induction machines
Get PDFInduction machines (IMs) are the driving force in industries such as manufacturing,
transportation and wind power generation. Hence, it is essential to reliably detect faults in IMs so
as to enhance production quality in manufacturing and avoid operational degradation. However, it
is still challenging to reliably detect faults in IMs as fault feature properties could change under
variable IM operating conditions. The first objective of this thesis is to develop an enhanced
empirical mode decomposition (EEMD) technique to detect an IM broken rotor bar (BRB) fault
based on motor current signature analysis. In the developed EEMD technique, a phase insensitive
similarity function is initially suggested to determine the representative intrinsic mode functions
(IMFs). Moreover, an optimized adaptive multi-band filter is suggested to process the current
spectrum and to recognize the fault characteristic features. Likewise, a modified whale
optimization algorithm (MWOA) is proposed, which is utilized to optimize the parameters in
adaptive multi-band filter. Finally, a reference function is recommended to enhance feature
properties and IM fault detection. The effectiveness of the proposed EEMD technique is verified
through experimental analysis under different IM operating conditions. [...
Factors impacting the referral to, enrollment in, and completion of cardiac rehabilitation within Northwest, Ontario
Get PDFNorthwest Ontario has higher rates of cardiac hospitalization compared to Southern Ontario for reasons not fully understood. However, cardiac rehabilitation (CR), a proven secondary prevention strategy, remains underutilized in Northwest Ontario. This study therefore aims to evaluate CR utilization and factors that impact access to CR. We also examined how CR may impact cardiac-related rehospitalization in Northwest Ontario. Methods: A retrospective cohort study was selected to analyze patients discharged with a cardiac-related index event at the Thunder Bay Regional Health Sciences Centre (TBRHSC) between July 2014 and December 2017 and subsequently followed until February 2023. Binary logistic regression and Cox proportional hazards models were used to identify factors influencing CR referral, enrollment, completion, and time to cardiac-related rehospitalization. Findings: Of the 448 eligible patients, 93.1% were referred to CR, of those only 51.7% enrolled, and of those that enrolled about 41.9% completed the program. The overall completion rate from the 448 eligible patients was therefore 19.9%. Enrollment was positively associated with having a partner (OR=3.14, p<0.01) and being female (OR=2.06, p<0.01) and negatively with drive time (OR=0.97, p=0.03). A family history of heart disease was the only factor associated with CR completion (OR=2.18, p=0.02). CR completion delayed time to rehospitalization (HR=0.69, p=0.05), with a 31% lower risk of rehospitalization among those completing CR in our unadjusted analysis. However, after adjusting for covariates, this impact became non-significant. Conclusion: Although referral rates are high due to a systematic process at the TBRHSC, CR enrollment and completion in Northwest Ontario remain suboptimal. Barriers include gender disparities and geographic accessibility. While completing CR appears to reduce cardiac-related rehospitalization, the overall impact on mitigating the cardiovascular disease burden in Northwest Ontario may be limited due to low CR completion rates. Further research is needed to quantify the long-term benefits of CR completion and identify strategies to improve completion rates in this region
Social-ecological resurgence through farmers’ traditional knowledge and agroecology in Pakistan
Get PDFThere is an urgent need to transform global food systems. Basic food supply chains have
been disrupted due to the structural vulnerabilities within the dominant food system. Scholars,
ecologists, smallholder farmers, economists and activists are increasingly advocating for
agroecology as part of a path forward, emphasizing the importance of drawing on the latest
agricultural research while harnessing farmers’ traditional knowledge to drive social-ecological
resurgence.
Farmers’ traditional knowledge is essential to agroecology and social-ecological systems.
The basic understanding that humans are an integral part of the natural world, interwoven with
the environment, rather than separate from it, is necessary for comprehending the complex
relationships that rule our existence. This study focuses on Pakistan, an agricultural country,
constantly influenced and pushed towards industrial agriculture. Industrial agriculture relies on
high yielding variety seeds, synthetic fertilizers, and pesticides to boost food production.
However, this approach has damaged the ability of farmers to depend on their local ecosystems
for food. The research explores how traditional agroecological knowledge has been embraced as
a form of social-ecological resurgence in Badin, Sindh, Pakistan. [...
Experimental investigation of effect of cement content and sulphate concentration on loading rate-dependent fracture behaviour of CPB under Mode I, II, and III loading conditions
Get PDFCement paste backfill (CPB) technology is becoming the standard mine backfilling approach in
the mining industry as an environmentally friendly and cost-effective way to manage tailings. Most
importantly, CPB plays a critical role in ground support to the surrounding rock mass to ensure
the safe and effective operation of the mine. After placement into the mined-out voids, the CPB
structure is subjected to complex loading conditions. Due to the dependency of mechanical
behaviour on the loading rate, CPB may demonstrate distinctive response and fracture failure
characteristics under field loading conditions. However, previous research has primarily
concentrated on traditional geomechanical behaviours, ignoring the impact of loading rate on the
fracture behaviour of CPB, which significantly influences the assessment of mechanical behaviour
and performance of in-stope CPB. Meanwhile, as a cementitious composite, the chemical factors,
including cement content and sulphate concentration, dominate the evolution of the mechanical
properties of CPB. Therefore, it is of theoretical and practical importance to investigate the effects
of cement content and sulphate concentration on CPB's loading rate dependent fracture behaviour.
The research aims to evaluate the loading rate dependent fracture behaviour and properties of CPB
under different loading conditions. [...
Becoming-the-dash: exploring the connections between landrace breeding and an eco-social approach to heal
Get PDFSeed–people relationships date back millennia but have been dramatically reorganized in
the last 100 years. This reorganization is just one part of the vast array of interconnected factors
that together have led to the entrenchment and domination of the current industrial food system.
This food system, in turn, is a major driver of global environmental degradation. The results of
the ongoing accelerating deterioration of the health of the planet have profound consequences for
the health of all beings that live upon it. While much research has been done exploring the role
of food systems in influencing the health of both people and planet, less is understood about the
role that seeds play. Landrace seed breeding is a traditional form of seed–people relationship in
which both are understood to be engaged in a co-evolutionary process of adaptation. In contrast
to modern seed–people relationships in which seeds have been commodified and privatized,
landrace breeding is understood to be a collaboration between seeds and people. This thesis
considers the ways in which landrace seed breeding is connected with an eco-social approach to
health through the exploration of the relationships that exist between seeds and people within the
context of an ongoing landrace breeding project in Ontario, Canada. Rooted in posthuman and
assemblage theory, and employing posthuman methodologies, this study takes the shape of a
multispecies ethnography in which seven humans and five landrace populations of watermelon
participated. This research found that the relationships between growers and watermelons created
a unique space from which a re-orientation of worldviews, new perspectives, and new stories
about how humans relate with other species could emerge. In light of the ongoing calls for new
ways of knowing and doing by those seeking to address the growing challenge of supporting
health from an eco-social perspective, this research suggests that landrace seed breeding may be
of importance beyond the agronomic benefits it is known to provide. This research also
exemplifies the relevance and utility of posthuman and assemblage thinking (as both theory and
research methodology) in facilitating a reimagining of the world around us and the place and role
of humans within it