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GROWTH RATE, ELEMENTAL AND BIOCHEMICAL COMPOSITION, AND SINKING DYNAMICS OF SMALL NANOPLANKTONIC DIATOMS: IMPLICATIONS FOR SEASONAL BIOGEOCHEMICAL CYCLING IN MARINE ECOSYSTEMS
No full textDiatoms are a highly diverse group of phytoplankton that contribute approximately half of global marine primary production and span a wide size range from less than 3 μm to more than 1000 μm in diameter. To date, most studies have focused on medium-sized diatoms between 4 to several 10s of µm in diameter. There is accumulating evidence that small nano-sized diatoms (> 2 and <4 µm in diameter) are common members of phytoplankton communities. Laboratory experiments were conducted to quantify the growth rate, elemental (C: N: Si: P), and macromolecular (protein, carbohydrate, lipids, RNA, and DNA) composition of two nanoplanktonic diatoms, Minidiscus trioculatus (CCMP 501) and Minutocellus polymorphus (CCMP 496) in comparison to the slightly larger (~5 μm) Thalassiosira pseudonana (CCMP 1335), across a gradient of irradiance (5–800 μmol photons m⁻² s⁻¹) and temperature (5–25 °C). Results showed that carbon to nitrogen (C: N) ratios were not size-dependent, but C: P, N: P, and Si: N were consistently lower in the small nanoplanktonic diatoms. The low C: P and N: P in the small nanoplanktonic diatoms are correlated with elevated of DNA: C and DNA: P. Complementary year-round field sampling (2023-2024) of surface particulate organic matter (POM) from the Bedford Basin (44.69°N, 63.64°W) supported these findings, with the lower values of C: P and N: P and higher DNA: C in the smaller size fraction (0.4 - 3 μm) relative to a larger size fraction (3 -300 μm). There were pronounced seasonal variation in C: N: Si: P in both size fractions, with spring characterized by low C: N: P and high Si: C, suggesting diatom dominance in both size fractions in spring. Elevated RNA: DNA and RNA: protein ratios during spring further supported rapid diatom growth in Spring. To evaluate whether small nanoplanktonic diatoms can sink as rapidly as larger species, a set of sinking experiments were conducted comparing the rates of M. trioculatus and M. polymorphus with that of the ~13 μm diatom Thalassiosira weissflogii (CCMP1010). Sinking experiments revealed that small nanoplanktonic diatoms, especially when forming chains or aggregates, can sink at rates comparable to or exceeding those of larger diatoms. Sinking rates increased during stationary phase, likely due to physiological and morphological changes, though species-specific responses to light and aggregate structure moderated this effect. Integrated laboratory and field data reveal that small nanoplanktonic diatoms, characterized by distinct elemental stoichiometry (low C: P, N: P), elevated DNA content, and enhanced sinking potential during aggregation significantly influence marine nutrient cycling, carbon export efficiency, and food web dynamics over different seasons
9/11 and the War on Terrorism: What It Means for Canadian Islamic Organizations
No full textThis thesis explores the impact of post-9/11 counterterrorism policies on Muslim
charities and non-profit organizations in Canada. Following the September 11 attacks,
Canada introduced a series of legislative and regulatory measures, including the Anti-
Terrorism Act (2001) and the Proceeds of Crime (Money Laundering) and Terrorist
Financing Act, which expanded state surveillance and enforcement powers. Drawing on
secondary sources, this research analyzes how these policies disproportionately affected
Muslim-led organizations through audits, revocations of charitable status, and
heightened scrutiny. The study situates these developments within broader international
pressures, especially from the United States and the United Nations, and critically
examines their implications for civil liberties, multiculturalism, and the role of Islamic
civil society in Canada. By mapping the intersections between national security, legal
reform, and racialized governance, the thesis contributes to a growing body of
scholarship on securitization and the marginalization of minority communities in the
post-9/11 era
Who Gets to be the ‘Ideal Gay’?: Queer Men’s Conflict and Microaggressions as Identity and Community Development
No full textIn this thesis, I investigate how ingroup negative interactions such as conflict, discrimination, and microaggressions impact how queer men in Halifax, Nova Scotia see themselves and their communities of queer men. To do this, I engage in qualitatively focused mixed methods analysis of 67 survey responses and 21 interviews with queer men currently living in Halifax, Nova Scotia. I engage with the literature on queer men’s inequalities, intersectionality, masculinity, stigma, and deploy the concepts of imagined community, infighting, and microaggressions to illustrate how queer men’s interactions influence how they see themselves and their broader community. My findings illustrate that queer men’s negative interactions extend far beyond negative slights or interpersonal spats, and instead represent queer men’s efforts to defend, affirm, and contest what they carry as the internalized image of the ‘ideal queer man.’ I call this process microaggressive identity conflict, bridging the gap between interpersonal slights and collective identity construction. In this way, queer men, when engaging with one another, deploy scripts of queer culture and behaviour and respond to local and broad narratives of what it means to be a queer man. Rather than representing interpersonal pettiness, microaggressions among queer men are instead part of a process of constantly defining and contesting queer community and collective identity
ADVANCED MOLECULAR TOOLS FOR WASTEWATER TREATMENT OPTIMIZATION WITH FOCUS ON SLUDGE BULKING
No full textEffective microbial population management is critical to the performance of wastewater treatment operations, particularly in addressing filamentous bulking, which compromises sludge settling and effluent quality. Traditional bulking indicators, such as the sludge volume index (SVI), and microscopic identification of filamentous bacteria is typically performed only after bulking has occurred. This highlights the need for early-warning indicators of bulking events. The present study investigates the application of advanced molecular tools within a full-scale wastewater treatment context, evaluating whether these techniques offer advantages over traditional monitoring methods in managing activated sludge systems.
Consequently, a full-scale evaluation was initiated to assess the predictive value of the specific floc-bulking Adenosine Triphosphate (s-fbATP) and to investigate the microbial basis of bulking. Initial system-wide assessments revealed clear ecological differentiation between two intermittently aerated tanks, which operated in either online (active) or offline (inactive) modes depending on seasonal conditions and hydraulic load. Principal coordinates analysis (PCoA) showed that microbial communities in Aeration Tank 3 (AT3) were tightly clustered, indicating ecological stability, whereas communities in Aeration Tank 2 (AT2) exhibited marked separation between active and inactive operational states. Multivariate analysis of variance (MANOVA) confirmed a significant tank-state interaction in AT2 but not in AT3. Based on these findings, AT3 was selected for detailed microbial and operational analysis.
Time-series analysis over an 18-month period indicated that increases in s-fbATP consistently preceded rises in SVI by approximately 7 days, with the strongest cross-correlation (r = 0.67) observed when s-fbATP levels exceeded the 50% threshold, indicating conditions that required operational intervention. These elevated s-fbATP periods were frequently characterized by declining effluent quality, as indicated by increased BOD (22.0 ± 6.8 mg/L) and COD (129.9 ± 1.9 mg/L). Conversely, when s-fbATP values remained below the 30% interrupt ratio, effluent quality improved, with average BOD and COD levels of 7.0 ± 1.7 mg/L and 94.4 ± 20.4 mg/L, respectively.
A filtration-based validation test confirmed that the DNA retained on a 250 µm filter used as part of the fbATP test was in fact enriched in filamentous and variable filamentous bacteria. Principal component analysis (PCA) revealed distinct community separation between the filter-retained fraction and the filtrate, supporting the analytical specificity of the fbATP assay for filamentous biomass, but additional verification in more locations and conditions is needed.
Episodes of bulking were statistically associated (p < 0.05) with elevated levels of organic loading (COD, F/M), ammonia, sulfate, and chloride. 16S rRNA gene sequencing and Thiothrix-specific quantitative PCR identified Thiothrix as the dominant filamentous genus; however, its abundance explained only a small fraction of the variation in s-fbATP and SVI. Ridge regression and microbial community analyses suggested that multiple taxa were associated with bulking events. Notably, increases in filamentous genera classified as Mycobacterium, Flavobacterium, and Acinetobacter showed positive correlations with chromium and nickel concentrations (r = 0.72), these findings are based on limited samples. While Thiothrix abundance showed a positive correlation with sulfate (r = 0.51) and higher pH; it was negatively associated with cadmium, lithium, titanium, and selenium.
Overall, the data indicate that s-fbATP showed promise as an operational metric and a indicated a potential one-week early-warning signal for sludge bulking and effluent quality deterioration., which would require more widespread validation. The results also suggest that filamentous growth is primarily driven by community-level responses, involving multiple microbial taxa rather than a single pathogenic genus. Routine monitoring of s-fbATP, particularly when integrated with molecular profiling techniques, could enhance early detection and support more proactive management of sludge settleability and effluent quality in biological wastewater treatment systems
MICROGLIAL ACTIVATION IN THE CAT DORSAL LATERAL GENICULATE NUCLEUS FOLLOWING RETINAL INACTIVATION
No full textAmblyopia is the leading cause of monocular vision loss in children. Success in treating amblyopia using conventional methods such as patching and atropine penalization are hindered by compliance issues, rigid treatment schedules, and a short treatment window during young childhood. Thus, alternative treatments addressing these barriers are necessary to improve visual outcomes. Retinal silencing, by administering intravitreal injections of tetrodotoxin (TTX), is a potential treatment for amblyopia in lieu of patching or penalization. Fellow eye retinal silencing has shown good results in promoting visual recovery of the deprived eye, with no permanent detriment to the silenced eye. However, the underlying mechanisms that protect the eye during silencing are not fully understood. Microglia are a subtype of glial cells involved in mediating the development of the synaptic network in the central nervous system. The current study sought to determine if microglia are involved in a homeostatic response that protects the synaptic network against lowered neural activity elicited by retinal silencing. In other words, how are synapses-serving the inactivated eye protected from perturbation? Microglial activation was investigated as a possible protective mechanism by measuring ionized calcium binding adaptor molecule 1 (Iba1) immunolabeling within the silenced- eye layers of the dorsal lateral geniculate nucleus. The results of this study revealed that retinal silencing in young animals activates microglia, and that retinal silencing in older animals did not elicit such activation. These findings raise the possibility that activation of microglia mediates a homeostatic response to protect against retinal silencing-induced synaptic modifications. The current study also showed that retinal silencing in younger animals activates microglial transiently, as activation is not sustained following TTX with a period of binocular vision. As TTX treatment stands as a possible alternative treatment for human amblyopia, it is important to understand how TTX affects the synaptic network of the visual system
Blended to be better: Design, characterization, and functionalization of recombinant chimeric spider silks for tailored biomaterials
No full textSpider silks are protein-based biomaterials renowned for their exceptional strength and extensibility, with potential applications in the biomedical, textile, and automotive industries. Orb-weaver spiders produce up to seven silk types for functions such as locomotion, web construction, egg protection, and prey wrapping. The cannibalistic and territorial behavior of spiders limits large-scale harvesting of natural silk, highlighting the importance of recombinant silk production. This thesis focuses on the design, production, and characterization of recombinant chimeric silks with tailored properties. A pyriform-aciniform silk fusion protein, Py2W2, was engineered by fusing two pyriform (Py) and two aciniform (W) silk repeat units. When wet-spun into fibers and stretched in air, water, or ethanol, Py2W2 exhibited tunable mechanics. Air-stretched fibers reached ~157% extensibility, comparable to natural flagelliform silk, while ethanol-stretched fibers achieved superior strength. These properties exhibited a correlation with secondary structure, where increased β-sheet content enhanced strength. Py2W2 fibers also showed water-compatibility absent in Py2 fibers and outperformed Py2 and W2 fibers in mechanical tests. As an alternative strategy, composite fibers (Py2+W2) were produced by mixing Py2 and W2 proteins prior to spinning. Like Py2W2, composite fibers displayed tunable mechanics influenced by post-spin stretching, though variability was observed in some spinning conditions. Further optimization of spinning process offers a practical route for generating tunable composite fibers without complex fusion designs. To introduce biological functionality, a chimeric protein W2Cma2ap-55 was designed by combining aciniform repeats (W2), a major ampullate silk C-terminal domain (Cma2), and the G-protein-coupled receptor (GPCR) ligand apelin-55 (ap-55). Films and fibers derived from W2Cma2ap-55 retained intact ap-55, as confirmed by antibody recognition. Compared with W2Cma2 fibers, W2Cma2ap-55 fibers exhibited higher strength and toughness with similar extensibility. Both film types were noncytotoxic to HEK 293A cells, and W2Cma2ap-55 films activated ERK phosphorylation, confirming apelin-55-mediated GPCR signaling. Similarly, cells adhered to W2Cma2ap-55 fibers, demonstrating their suitability as bioactive scaffolds. Overall, this work establishes chimeric silks as versatile biomaterials. Rational protein design and processing enabled tailoring of mechanical properties (Py2W2, Py2+W2) and the integration of bioactivity (W2Cma2ap-55). These findings highlight the potential of engineered spider silks for advanced biomedical and functional applications
Spider Seiðr Sympoiesis
No full textAnthropocentrism has blinded designers to the impact of their work on non-humans, while simultaneously limiting a rich source of inspiration. It is incumbent upon us to pursue kinder modes of co-existence with the more-than-human lives who we share a world with. This project’s eclectic experimentation combines methodologies from the disciplines of science, witchcraft, and design, pursuing a means for interacting with common cellar spiders (Pholcus phalangioides). Across a sequence of eight rituals, the contributing spiders and I produced a series of co-authored architectonic sigils. These objects, together with the tools and procedures necessary to create them, express a desire for kin-making between species, while reflecting architecture as a liminal zone and practice which connects humans and spiders. The processes and ethos informing these rituals are collected in a grimoire, a document which teaches the reader how to connect with and learn from spiders, both as embodied beings and symbolic figures
Representing Gait Outcomes For Advanced Knee Osteoarthritis Using a Wearable Inertial Sensor System
No full textThis thesis aimed to develop an efficient Inertial Measurement Unit (IMU) protocol for capturing kinematic and kinetic gait patterns in knee Osteoarthritis (OA) patients in a free-living environment, moving beyond costly lab-based motion capture. The study involved end-stage knee OA patients before and after knee arthroplasty (KA).
The first objective showed good statistical agreement between IMU-derived and motion capture discrete metrics for knee adduction and flexion angles, with differences within clinically acceptable limits (minimum clinically important difference or typical inter-session variability).
The second objective explored using IMU-derived features (accelerations/angular velocities) to estimate the temporal patterns of kinetic waveforms (flexion/adduction moments). Shank-only models explained over half the variance, improving with foot sensor data (R2=0.55-0.69).
These results validate the ability to capture clinically relevant gait outcomes with IMU's, enabling the transition to remote, continuous monitoring of OA progression and recovery outside of the clinic
PUBLICLY FUNDED GUIDELINE-RECOMMENDED MEDICATIONS DISPENSED TO COMMUNITY-DWELLING OLDER ADULTS IN NEW BRUNSWICK FOLLOWING HOSPITAL DISCHARGE FOR MYOCARDIAL INFARCTION BETWEEN 2009 AND 2017
No full textBACKGROUND: Pharmacologic therapy plays a central role in secondary prevention following myocardial infarction (MI). Evidence from randomized controlled trials has demonstrated that β-blockers, statins, renin–angiotensin–aldosterone system (RAAS) inhibitors, and antiplatelet agents, particularly P2Y12 inhibitors, reduce mortality, recurrent infarction, and stroke post-MI. Studies in Canada have shown that their use in routine practice remains variable and have not examined the determinants of medication use since P2Y12 inhibitors became standard of care. In New Brunswick (NB), population-based evidence is limited. Understanding these variations is critical for assessing the quality of post-MI care and informing system-level improvements. OBJECTIVES: This study aimed (1) to calculate the annual proportion of community-dwelling older adults (66 years or older) in NB with publicly funded drug insurance and received a dispensation for each guideline-recommended medication class: β-blockers, statins, RAAS agents, and P2Y12 inhibitors, within 90 days of discharge for MI between 2009 and 2017, and determine whether this changed over time; and (2) to determine whether characteristics of the discharging physician were associated with the likelihood of an individual receiving a P2Y12 inhibitor within 90 days of discharge. METHODS: A retrospective, population-based cohort study was conducted using linked administrative health data. The cohort included community-dwelling older adults who were discharged alive from hospital with a primary diagnosis of MI (ICD-10 I21) and had public drug coverage during the study period. Dispensation of each recommended medication within 90 days of discharge was identified from outpatient pharmacy claims. Logistic regression models with generalized estimating equations were used to estimate the associations between physician characteristics and P2Y12 inhibitor use, adjusting for patient age, sex, and length of hospital stay. RESULTS: Among the 2,674 eligible patients, the median age was 78 years (IQR: 71 to 84), and 47% were female. Overall, 79% of patients received a β-blocker, 83% a statin, 72% a RAAS inhibitor, and 70% a P2Y12 inhibitor within 90 days of discharge. Dispensation rate for β-blockers, statins, and P2Y12 inhibitors remained stable across the study period, while RAAS inhibitor use declined. Physician-level variation was evident, compared to cardiologists, patients discharged by general practitioners (OR 0.38; 95% CI 0.28, 0.51) or other specialists (OR 0.47; 95% CI 0.32, 0.68) were less likely to receive P2Y12 inhibitors post-discharge. Patients discharged by female physicians were less likely to receive P2Y12 inhibitors (OR 0.69; 95% CI 0.51, 0.92). No statistically significant associations were found with physician graduation decade or training location. DISCUSSION: Post-MI use of evidence-based pharmacotherapies among publicly insured older adults in NB was comparable to rates reported elsewhere in Canada and remained below recommended targets. The observed variation in P2Y12 inhibitor use across physician groups suggest that structural factors, such as clinical specialization, and drug reimbursement policies, may influence access to guideline-recommended therapies