14277 research outputs found
Sort by
A Minkowski problem for -concave functions via optimal transport
No full textThe notions of the Euclidean surface area measure and the spherical surface area
measure of -concave functions in ℝₙ, with −1/n < < 0, are introduced via a fi rst
variation of the total mass functional with respect to the -sum operation. Subsequently,
these notions are extended to those for -concave measures. We then study
the Minkowski problem associated with the Euclidean surface area measures of -
concave measures via optimal transport
Covert age-related differences in agility are related to both muscle strength and integrity of the corticospinal tract
No full textBackground: Agility involves moving efficiently without losing balance, requiring muscular strength and neuromuscular capacity. Maintaining agility promotes aging with vitality, living without frailty, and reduced fear of falling. Factors that influence age-related differences in agility are unknown.
Methods: Participants were recruited to determine whether quadriceps strength or integrity of the corticospinal tract (CST) influenced age-related differences in agility. Participants underwent Transcranial Magnetic Stimulation to measure CST integrity and completed a lower limb agility hopping task. CST excitability was calculated as active motor threshold intensity, the lowest stimulator output that produced a motor evoked potential. We used regression modelling to predict the contribution of quadriceps strength and CST integrity to lower limb agility, when controlling for sex.
Results: Greater quadriceps strength correlated with longer hop length (r = .581,p <.001) and reduced hop length variability (r=-.384,p=.039). Lower active motor threshold correlated with longer hop length (r=-.364,p=.048) and reduced hop length variability (r=.478,p=.007). Decreased quadriceps strength significantly predicted shorter hop length (R²=.393,p=.002) while higher active motor threshold predicted greater hop variability (R²=.182,p=.036).
Conclusions: Agility involves a combination of muscle power and coordination, which can be tested with a hopping agility task. CST integrity predicted coordination on the task, but not strength, even when controlling for sex.Includes bibliographical references (pages 51-62
Influences on the balance between energetics and risk in snowshoe hares
No full textAnimals balance acquiring food for energy while minimizing their risk of predation, but climate or habitat features can tip the scales. I used snowshoe hare (Lepus americanus) to test how external variables influence foraging and survival. First, I used winter coat-colour mismatch to test the Camouflage Hypothesis. I predicted that white hares mismatched on a snowless winter background would be more vulnerable to predation than matched hares. Instead, mismatched hares had lower mortality risk than matched hares. Temperature and snow depth, not mismatch, influenced survival and foraging behaviour. Next, I tested the Risk Allocation Hypothesis with a novel risk simulation experiment in the context of spring environmental factors. Hares did not allocate risk based on simulated risk or weather conditions. Instead, hares were risk averse as a function of canopy cover. Taken together, my results demonstrate that multiple mechanisms likely impact the energetics-risk balance. Snow depth and canopy cover have direct implications on predation risk, while temperature impacts energetics; however, effects may not be detectable if conditions do not represent an energetic challenge. My work highlights the idiosyncrasies of place considering previous results across the hare range, and contributes to mismatch and behavioural frameworks for a seasonally coat-colour changing species.Includes bibliographical reference
Exploring models and approaches for training sustainable food systems in dietetic practice: a pilot study
No full textBackground: A Sustainable Food System (SFS) is an emerging area in dietetic practice that addresses food waste, hunger, malnutrition, and ensures that everyone has access to safe, affordable food while preserving biodiversity.
The International Confederation of Dietetic Associations (ICDA) has developed three online learning modules to train nutrition professionals in SFS. However, the effectiveness of these modules has yet to be evaluated.
Objective: This study evaluates the effectiveness of the ICDA's online learning modules in enhancing dietitians' confidence and competency in incorporating SFS principles into their practice.
Methods: A mixed-methods approach was employed, with 25 participants from Canada and Australia recruited through purposive sampling. Participants engaged in three 90-minute online focus group sessions and completed baseline and three-month follow-up surveys to assess confidence and competency in SFS. The focus groups evaluated the modules' design, content, and impact on knowledge and practice. Focus group data were analyzed using thematic analysis.
Results: After completing the ICDA modules, the three-month follow-up survey revealed increased competence and confidence compared to baseline, indicating a positive impact of the modules on dietetic professionals. The focus group data showed that participants' competence and confidence were influenced by their learning environment and approach, engagement and interaction, application and practicality
Discussion: The findings suggest that the knowledge and skills gained through the ICDA modules can enhance dietetic professionals' confidence and competency in applying SFS
principles to their practice. This research supports the integration of SFS into dietetic practice, ultimately benefiting population health. These findings will be used by the ICDA to improve the modules for dietetic professionals.Includes bibliographical references (pages 129-142
Synthesis of iron amino-bis(phenolate) complexes and their application in ring-opening copolymerizations
No full textThree iron amino-bis(phenolate) complexes featuring differing pendant donor groups were
synthesized in this work. The structures include pyridyl, morpholinyl and amine groups,
respectively, and were characterized by various techniques including MALDI-TOF MS,
UV-Vis spectroscopy and single crystal X-ray diffraction. These complexes were further
explored for the potential synthesis of cationic iron amino-bis(phenolate) complexes
through halide abstraction with Lewis acids. The resulting reaction solutions were
characterized by similar methods used to study the neutral complexes, including UV-Vis
spectroscopy and MALDI-TOF MS. Metal-based amino-bis(phenolate) complexes, both
neutral and cationic, have been previously used as catalysts in ring-opening polymerization
(ROP) reactions. The use of earth abundant element-based catalysts, such as iron
complexes, provides environmental and economic benefits to potential catalytic
applications. Subsequently, the reactivity of the iron amino-bis(phenolate) complexes
synthesized here, and their protioligands, was investigated for ring-opening
copolymerization (ROCOP) reactions. This reaction screening studied the coupling of
epoxides and anhydrides for polyester synthesis, as well as epoxides and CO₂ for selective
poly- or cyclic- carbonate formation. The products obtained were characterized by ¹H NMR
spectroscopy, GPC and MALDI-TOF MS, with CO₂ reactions monitored via in-situ FT-IR
spectroscopy. The results of these studies will be presented and discussed throughout this
thesis
Towards human-quality drum accompaniment using deep generative models and transformers
No full textAutomatic music generation has garnered significant interest among musicians and
composers. In particular, the task of accompaniment in music generation presents
unique challenges, as it involves generating an instrument track responsive to other
played instruments. This project focuses on accompanying musicians with automatically
generated tracks, specifically accompanying bass guitar players with AIgenerated
drum tracks. The proposed system was trained on multi-track songs to
capture the connection between bass and drum tracks using the framework of Conditional
Generative Adversarial Networks (CGANs). Unlike typical AI-generated drum
tracks, which often lack nuanced dynamics, human-performed drums feature expressive
elements such as velocity—the varying loudness of each strike. To capture this
expressiveness, our transformer model is trained on human drum performances and
focuses on assigning realistic velocities to the generated drum hits. An ablation study
was conducted, and the results indicate that combining pitch and velocity generation
into a single network significantly reduces music quality (measured by groove
consistency), reinforcing our approach of separating velocity assignments to maintain
coherent drum patterns while enhancing expressiveness. We also evaluate the
generated music using objective metrics, demonstrating the models’ performance and
evolution during training. The drum generation system supports real-time interaction,
enabling spontaneous live jamming sessions. Simplifications facilitate real-time
operation, and we provide results from sample sessions.Includes bibliographical references (pages 44-47
Exploring the spatial distribution of urban greenery in small and medium-sized Canadian cities through a spatial equality lens
No full textUrban greenery (UG) supports healthier and more sustainable cities. Therefore, it is important to study how UG is distributed among different population groups. Although much progress has been made, key gaps remain. Most studies focus on large cities, leaving small and medium-sized cities understudied. Many also rely on a single spatial scale and treat UG as an aggregated variable, despite different UG types offering varying benefits. Additionally, access to UG has received less attention than availability. To address these gaps, I used the St. John’s Census Metropolitan Area, NL, Canada, as a case study. Data were collected from various sources, including Sentinel-2 imagery and the Canadian Census. A combination of spatial and aspatial methods were used to examine how tree and grass cover were distributed among population groups at two spatial scales: Census Tract and Dissemination Area. Accessibility to urban parks was also assessed using two methods—one considering road network and one not. The results demonstrated notable inequalities in UG distribution and park accessibility. These patterns varied by UG type, spatial scale, and assessment method. The findings advance knowledge of UG distribution and offer practical guidance for urban planning and policymaking towards creating more sustainable, resilient, and equitable cities
Effect of crude oil on defence-relevant biomarker gene expression in early-life stage lumpfish
No full textThis thesis investigated the response of early-life stage lumpfish (i.e., larval and juvenile) to crude oil at the mRNA level. A pilot study was conducted on juvenile lumpfish, which were exposed to five chemically-enhanced water-accommodated fraction (CEWAF) treatments for 24 h in a static system. Through multiple sequence alignment (MSA), phylogenetic and synteny analyses, five lumpfish aryl hydrocarbon receptor genes were studied and named following those in Japanese pufferfish (Takifugu rubripes). The results of real-time quantitative polymerase chain reaction (qPCR) showed significant induction for ahr1a, ahr2a and cyp1a1 in the liver of oil-exposed juvenile lumpfish. Based on these results, another exposure experiment was done on 50 days post-hatch lumpfish larvae in a similar exposure set-up, with two additional CEWAF treatments. The qPCR results indicated that the 24-h CEWAF exposure might modulate immune and redox function in larval lumpfish. Moreover, a Spearman correlation analysis and principal component analysis suggested that Ahr may affect the expression of genes involved in cardiovascular development and immune response. Collectively, these results provide new insight into the influence of acute crude oil exposure on the transcript levels of targeted genes in larval and juvenile lumpfish.Includes bibliographical reference
Role of CYP24A1-mediated calcitriol metabolism in regulating fetal bone and mineral metabolism
No full textVitamin D is essential for fetal mineral homeostasis and bone development, primarily through its active form, calcitriol. In normal human and rodent fetuses, calcitriol circulates at low levels due to increased breakdown via CYP24A1. Prior studies show that these low levels are not necessary for fetal mineral balance, as vitamin D deficiency or calcitriol receptor ablation does not disrupt it. However, the effects of elevated calcitriol during fetal development remain unclear. Mutations in CYP24A1 cause infantile hypercalcemia type 1, but whether this condition begins in utero is unknown. We hypothesized that Cyp24a1 ablation in fetal mice would lead to high calcitriol, hypercalcemia, and increased placental calcium transport. Using Cyp24a1⁺ᐟ⁻ breeding, we analyzed blood, placentas, and fetuses at ED 18.5, with placental transport assessed at ED 17.5.
Cyp24a1⁻ᐟ⁻ fetuses had high calcitriol, hypercalcemia, and increased FGF23, but reduced phosphorus and unchanged PTH. While placental calcium transport genes were upregulated, actual transport rates remained normal. Fetal mineral content, placental weight, and skeletal morphology were unaffected. In summary, Cyp24a1 ablation caused in utero hypercalcemia and hypophosphatemia without altering placental transport or skeletal development, suggesting that infantile hypercalcemia type 1 originates before birth
An analysis of the discourse topics, discursive and ideological strategies in the political speeches of the ousted Arab leaders during the Arab Spring: a critical discourse analysis
No full textThis study aims at exploring how the ousted Arab leaders Zine El Abidine Ben Ali of Tunisia, Hosni Mubarak of Egypt, and Muammar al Qaddafi of Libya de/legitimize the Self and the Other in their political speeches during the Arab Spring via the use of discourse topics (macro-strategies), discursive strategies, and ideological strategies. In order to achieve this objective, I employ two theories of Critical Discourse Analysis (CDA). Reisigl and Wodak’s (2001, 2009) Discourse-Historical Approach is utilized to identify how discourse topics and the discursive strategies of nomination, predication, and intensification/mitigation are used in the examined speeches to de/legitimize the Self/Other. Second, van Dijk’s (1998) Ideological Square is employed to identify the ideological strategies used by the three leaders to socially include/exclude the Self/Other. These two approaches highlights that integrating the social, historical, and political contexts of these speeches also helps to better understand how the concepts of de/legitimization of the Self/Other evolved over time. The study revealed that the three leaders use the discourse topics of the harmful effects of the protests and foreign intervention to negatively represent the Other. Counting the sacrifices and offering evidence of reforms, on the other hand, are used to positively represent the Self. All three leaders rely more on the nomination strategy to positively represent the Self, while they rely more on the predication strategy to negatively represent the Other. They rely on repetition as a tool of intensification mainly to gain sympathy and support from their audience. All speeches exhibit ideological overtones which are communicated via the ideological strategies of authorization, narrativization, moral evaluation, self-victimization, comparison, blame attribution, arousing emotions, and personification. Finally, a substantial portion of CDA research has traditionally concentrated on Western democratic political environments. This research expands the domain of CDA to non-Western authoritarian environments by analyzing the
speeches of Arab leaders. During crises, these leaders employed nationalistic narratives to establish themselves as protectors of national identity and stability. This emphasis on identity construction corresponds with the extensive CDA literature regarding the interplay between language and identity, especially in contexts where identity is utilized to advance political objectives.Includes bibliographical references (pages 243-269