30921 research outputs found
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Modulating functional brain connectivity using high-definition transcranial direct current stimulation (HD-tDCS)
No full textTranscranial direct current stimulation (tDCS) is a non-invasive technique for modulating brain activity and is widely used in cognitive neuroscience and clinical research. Conventional tDCS often affects broad cortical regions, limiting its precision when targeting complex regions like the dorsolateral prefrontal cortex (DLPFC). Earlier findings indicated mixed impact of tDCS on brain functional connectivity such that left DLPFC stimulation induced no significant effects, while right DLPFC stimulation increased functional connectivity in the target. High-definition tDCS (HD-tDCS) has been recently developed to improve spatial focality of current delivery, but its effects on functional connectivity have not been systemically investigated.
Conventional tDCS is limited by diffuse current spread and suboptimal electrode placement, reducing the specificity of stimulation. This study investigates the effects of HD-tDCS on different targets in the frontoparietal control network: the left DLPFC, right DLPFC, and left inferior parietal lobule (IPL).
Eighty healthy adults were randomly assigned to one of four groups: HD-tDCS targeting the left DLPFC, right DLPFC, left IPL, or sham. Participants completed cognitive assessments (MoCA, ANAM, BDI-II), followed by structural T1-weighted magnetic resonance imaging (MRI), resting-state functional MRI (rs-fMRI) and pseudo-continuous arterial spin labeling (pCASL). HD-tDCS (2 mA, 20 min) was administered using 9 electrodes positioned to optimize inward current to each target. Rs-fMRI and pCASL were repeated. ANAM was repeated after the scanning session. Functional connectivity and cerebral blood flow were analyzed using region-of-interest (ROI)-based approaches with each target as well as voxel-wise analyses. A 4×2 repeated measures ANOVA assessed time-by-condition interactions.
No significant interaction effects were identified in both behavioral outcomes or ROI-based imaging analyses. In the voxel-wise intrinsic connectivity analysis, significant interaction effects were identified in the cerebellar vermis, and post-hoc ROI analysis suggested that the intrinsic connectivity was significantly increased after the right DLPFC stimulation compared to the sham stimulation.
This study demonstrates asymmetric effects of HD-tDCS where only right DLPFC stimulation produced significant and selective increases in intrinsic connectivity in the cerebellar vermis. These findings underscore the need for further investigation into the mechanisms underlying the asymmetric effects of HD-tDCS and its potential implications for neuromodulation strategies in cognitive and clinical applications.October 202
Optimized emergency shelter ranking: a multi-criteria decision-making framework for post-disaster response
No full textThis thesis introduces a comprehensive multi-criteria decision-making (MCDM) framework
designed to optimize the selection and prioritization of emergency shelters during natural
disasters. Recognizing that effective shelter planning must extend beyond the basic objective
of survival, this study emphasizes the importance of accommodating the nuanced and diverse
needs of displaced populations, particularly refugees and vulnerable groups. To capture these
needs accurately, a set of detailed evaluation criteria was developed in direct collaboration with
the Emergency Management Organization (EMO) of Manitoba, Canada. This collaboration
ensured that the model reflects not only theoretical soundness but also practical considerations
rooted in field experience and operational constraints.
The core of the proposed methodology is an enhanced version of the Technique for Order of
Preference by Similarity to Ideal Solution (TOPSIS), a widely used MCDM method. To
address a major limitation of traditional TOPSIS—its sensitivity to the subjectivity of weight
assignment—the model incorporates a hybrid entropy-based weighting mechanism.
Specifically, it combines Shannon entropy and Wen entropy to compute objective and context-
sensitive weights for each criterion. Shannon entropy captures the variability in continuous
data, while Wen entropy adjusts for the significance of binary criteria. This dual entropy
approach results in a more balanced and unbiased evaluation process, allowing the model to
handle diverse data types with improved precision and interpretability.
The model is applied to a real-world case study in Manitoba, where hotels are evaluated as
potential shelters. Unlike previous studies that focus on hypothetical sites or vacant land, this
research deliberately evaluates existing, operational infrastructure to enhance the model's
deployability. The selected shelters are assessed across both quantitative factors (e.g.,
proximity to hospitals, capacity, structural safety) and qualitative or binary indicators (e.g., pet-
friendliness, accessibility, age-specific amenities). The model also introduces a tunable φ
parameter that enables decision-makers to simulate varying disaster scenarios by shifting the
relative importance of binary versus continuous data. This allows emergency planners to
account for the evolving nature of crisis conditions, such as weather changes, population
demographics, or transportation limitations.
A detailed sensitivity analysis, along with stability metrics such as standard deviation and rank
change (RC), was conducted to validate the robustness of the shelter rankings across different
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weighting schemes. The findings highlight key facilities that consistently perform well across
all scenarios, as well as context-specific shelters that may be optimal in certain emergencies.
These results provide actionable insights for emergency managers, enabling data-driven
decisions that can reduce response times, minimize population displacement, and prevent
repeated relocations during prolonged crises.
Beyond methodological innovation, this research contributes to disaster preparedness and
policy planning by creating a decision-support tool that is grounded in operational reality and
informed by human-centered priorities. By aligning academic modeling with field-based
expertise and real infrastructure, the study bridges the gap between theory and practice.
Moreover, its focus on the Canadian urban context fills an important gap in the global literature,
offering a replicable framework for other regions facing similar challenges. Ultimately, this
work enhances the resilience and efficiency of emergency response systems, ensuring that
shelter planning is not only mathematically sound but also socially responsible and practically
viable.October 202
Parent and caregiver preferences for eHealth programs
No full textBackground: Online programs serve as an important avenue for delivering mental health and parenting services worldwide. The quantity of online programs proliferated during the COVID-19 pandemic with developers emphasizing the potential to improve accessibility and reduce barriers of in-person programming (e.g., arranging transportation, childcare, and scheduling). However, Canadian parents’ and caregivers’ preferences for features they desire in online family mental health supports are unknown. Understanding these preferences would better allow for the creation of programs that are best suited to meet parents’ needs. Thus, the present study examined parent mental health program preferences, barriers to access, and how different sociodemographic factors predicted preferences for aspects such as program features (e.g., duration delivery format).
Methods: Self-report surveys were administered in 2023 via the online crowdsourcing platform AskingCanadians to parents and primary caregivers of children ages 0 to 5 years. Descriptive statistics examined parent mental health program preferences and barriers. Regression models examined sociodemographic predictors of these preferences and barriers.
Results: Participants identified a range of preferences across program structure and coaching, as well as challenges associated with program access. Parents most preferred programs with a web-based delivery format (72%), a duration of 2–4 weeks (27%), and psychologists as program coaches (51.4%). The most highly endorsed barriers were lack of time (42.2%) and limited internet access (25.1%). Sociodemographic factors including parent gender, household income, education, and ethnicity also consistently predicted preference for various program characteristics.
Conclusions: This research provides an important first step toward creating more accessible online mental health and parent mental health programs by ensuring the voices of the parents who will use these services are heard in program development and adaptation. Future research should investigate how to address accessibility and inclusivity barriers to participating in parent mental health programs for diverse families based on their differential preferences
Assessment of mpox knowledge, health-seeking behaviours and sexual activities in communities of the Democratic Republic of the Congo
No full textMonkeypox virus (MPXV), the causative agent of mpox, has caused 132,797 cases worldwide since 2022, with Africa being the most impacted region. Since 1970, the Democratic Republic of the Congo (DRC) has lived with the burden of this disease, accounting for more than 70,000 cases in 2024. Men who have sex with other men (MSM) and sex workers continue to be overrepresented for clade IIb mpox infection. Since the emergence of clade Ib and the rise in sexual-based transmission in dense sexual networks, key populations, including MSM and sex workers, have started to play an important role in the investigation of this disease. However, mpox knowledge and risk perception are not well elucidated among these populations. The purpose of this study was to evaluate the mpox knowledge of high-risk populations, including MSM, sex workers and other individuals at higher risk for mpox acquisition by sexual contact, in DRC, as well as their health-seeking behaviour and sexual activities. We recruited 2,794 participants, including 810 sex workers, 831 MSM, 118 participants that self-identified as MSM and sex workers, and 1,035 participants who identified as non-sex workers and non-MSM and were considered at-risk due to being recruited in the same areas as the key populations. Peer-educators led the recruitment in Kinshasa, Kwango, and North Kivu provinces. Among the recruited participants, 6.1% had heard of mpox before, with “direct contact with infected animals” being the most identified transmission mode. Furthermore, “people living in high-risk areas” was the most selected answer for the population most likely to contract mpox. Concerning sexual behaviours, the majority of sex workers reported engaging in transactional sex (96.0%), anonymous sex (91.6%), sex with multiple partners (90.3%) and sex in clubs or bars (88.4%). Regarding health-seeking behaviours, 59.6% of MSM and 49.4% of sex workers said they would go to a healthcare facility if they suspected a sexually transmitted infection. Our results accentuate the need to understand the source of information gaps and how to effectively reach these high-risk communities to educate them about mpox.October 202
Impact of oxygen and carbon dioxide levels on mortality in moderate to severe traumatic brain injury: a systematic review and meta-analysis
No full textBackground: Traumatic brain injury (TBI) remains a leading cause of morbidity and mortality worldwide. Secondary brain insults related to oxygenation and ventilation may affect outcomes in this high-risk population. The aim of this study was to perform a comprehensive review examining the relationship between oxygen and carbon dioxide thresholds and mortality to guide clinical care.
Methods: Eleven databases, including: MEDLINE, MEDLINE In-Process, Embase, the Cochrane Central Register of Controlled Trials, the Cochrane Database of Systematic Reviews, CINAHL, APA PsycINFO, Web of Science, Biosys, Scopus, and the Global Index Medicus, were systematically searched from inception to October 23, 2024. Included studies reported on adults ( 18 years) with moderate to severe TBI (msTBI) (Glasgow Coma Scale <13 or Head Abbreviated Injury Scale 3) and exposure to hypoxia, hypocapnia, or hypercapnia, with mortality or vegetative state data reported within 6 months. Vegetative state data was not reported, so all analyses were based on mortality. Pediatric or mild TBI studies, stroke-focused studies, and studies without mortality outcomes were excluded. The data were screened via Covidence software with multiple reviewers. No language or regional restrictions were applied. This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines. Quality was assessed via the Newcastle-Ottawa Scale (NOS) for Cohort Studies, and certainty of evidence was rated using GRADE. Four authors independently extracted data with verification by a second reviewer. The primary outcome was measured using odds ratios (ORs) with 95% confidence intervals (CIs), calculated separately for crude and adjusted effect estimates.
Results: Twenty-one cohort studies with 41,980 patients were included. Hypoxia and hypocapnia were significantly associated with increased mortality (aOR, 1.39; 95% CI 1.11–1.75; p =.005; aOR, 1.64; 95% CI 1.25–2.15; p <.001). Hypercapnia was not significantly associated with mortality (aOR, 1.74; 95% CI 0.91–3.32; p =.09).
Conclusions: In adults with msTBI, hypoxia and hypocapnia were independently associated with increased mortality, underscoring the importance of prompt recognition and targeted management of these secondary injuries. The role of hypercapnia remains unclear, warranting further investigation
Towards Spin Crossover in Pseudo-Octahedral Iron(III) Complexes of Strongly Absorbing Phenanthridine-Based N^N^O- Ligands
No full textParamagnetic complexes which can undergo spin crossover between different magnetic states that also strongly absorb light are highly attractive for the pursuit of optical magnetic technologies. Against this backdrop, we prepared a library of Fe(III) complexes ligated by monoanionic, tridentate N^N^O- ligands (RL: (2-R-(4-imino-methyl)-phenanthridinyl)]-5-R'-phenolate where R = tBu, F, OMe, R' = H or R = tBu, R' = tBu) bearing strongly absorbing -extended phenanthridine (benzo[c]quinoline) donors: [Fe(tBuL)2]PF6, [Fe(tBuLtBu)2]PF6, [Fe(FL)2]PF6, and [Fe(OMeL)2]PF6. The solid-state structures of three of the series were determined using single-crystal X-ray diffraction, confirming pseudo-octahedral coordination geometries. Electronic absorption spectra shows strong absorbances near 340 nm and 415 nm for the series due to -* and ligand-to-metal-charge-transfer (LMCT) transitions, respectively, along with a long absorptive tail that extends well into the visible region, only attenuating close to 850 nm. Magnetic measurements in the solid-state (SQUID magnetometry) and in solution (Evans’ Method) revealed the influence of ligand substituents. For example, the magnetic moment of [Fe(FL)2]PF6 in the solid-state remains more or less constant at a mT ~2.3 over a large temperature range (25-300 K) indicative of a mixed spin configuration that is maintained in solution at ambient temperature, while [Fe(tBuL)2]PF6 and [Fe(tBuLtBu)2]PF6 only reach values of ~1.5 at higher temperature. In comparison, the mT of [Fe(OMeL)2]PF6 undergoes a much more abrupt drop upon cooling, from ~2.5 to below 0.5 at 100 K, consistent with spin-crossover type behavior
Facilitating judicial legislative dialogue through the remedy of suspended declarations of invalidity in Canada
No full textThis thesis examines how courts have used suspended declarations of invalidity as a judicial remedy to encourage a dialogue with the legislature in Canada. It adopts a doctrinal approach and integrates a theoretical framework of dialogue. The findings suggest that suspended declarations have facilitated dialogue between courts and legislatures. This occurs when judicial review of laws prompts and receives a legislative response, ultimately advancing legal development in Canada. This thesis contributes to the understanding of how suspended declarations are used as mechanisms for institutional dialogue, demonstrating their significance in the development of Canadian laws.October 202
Possible many-body localized phases in Aubry-André systems
No full textAnderson localization, where quenched disorder leads to the localization of single-particle wave functions, has been studied extensively. However, the effect of interaction and non-random potentials on many-body localization (MBL) has gained attention recently. We investigate the dynamics of the interacting Aubry-André model to assess the stability of the many-body localized (MBL) phase. Our motivation to consider the Aubry–André potential as the disorder potential is to eliminate the avalanche mechanism, which often destabilizes MBL in systems with quenched disorder. We analyze the time evolution and the system-size scaling across a range of disorder strengths for the entanglement entropy, number entropy, and the Hartley number entropy. In the non-interacting case, our results confirm an Anderson localization transition at a critical disorder strength Dc = 2, which is consistent with earlier studies. However, when interactions are introduced, the number entropy appears to grow unboundedly as SN ~ ln ln t in the thermodynamic limit, even for large disorder. Meanwhile, the entanglement entropy grows logarithmically, S ~ ln t, and both entropies saturate in a correlated manner at finite times td ~ e^(L·D). These findings suggest that using a quasiperiodic potential to remove the avalanche mechanism does not stabilize true MBL behavior. Instead, the long-time dynamics are qualitatively similar to those found in systems with random disorder. In this thesis, we first introduce the fundamental concepts of thermalization, quantum quench, and symmetry-resolved entropies, then provide a study of localization, specifically in the Aubry-André model. Finally, we place our numerical results in the broader context of the current debate on the stability of many-body localized phases.October 202
Evaluating the impact of municipal wastewater strength on granulation in sequencing batch reactors
No full textThe impact of varying municipal wastewater strength on the formation and development of aerobic granular sludge (AGS) was investigated using three 5 L sequence batch reactors. To maintain the same organic loading rate, cycle lengths and primary effluent (PE) volumes were adjusted. The average influent chemical oxygen demand (COD) concentration for Reactors 1, 2, and 3 was 140±36.0 mg/L, 344±89.2 mg/L, and 503±145 mg/L, respectively.
Reactor 1 was fed dilute PE and successfully developed dense, spherical granules with a De Brouckere mean diameter of at least 0.6 mm within three months of steady operation. Throughout the study, Reactor 2 (fed unaltered PE) and Reactor 3 (fed high-strength PE) both contained a higher presence of flocs rather than granules. Although Reactor 3 displayed the highest phosphorus removal efficiency amongst all three reactors, granules did not mature or stabilize.
At steady state, the average SVI30 for Reactor 1 was 85±8 mL/gVSS, whereas the average SVI30 for Reactors 2 and 3 exceeded 150 mL/gVSS for most of the study. The average NH4-N removal for Reactors 2 and 3 was greater than 98% throughout the study. For Reactor 1, the removal rate declined from 96% to 65% after the aerobic period was shortened on day 159. For all reactors, the average PO4-P removal was poor throughout the study. However, on day 126 onwards, Reactor 3’s orthophosphate removal was 99%. After extending Reactor 1’s anaerobic period on day 159, the orthophosphate removal improved to 88%. From day 132 onward, Reactor 2 achieved an average PO4-P removal of 70%.
Overall, this study demonstrated that shorter settling and decanting times (under 5 minutes), combined with an HRT of 6 hours, created a high selective pressure and led to the development of dense, round granules in Reactor 1. In contrast, extended settling, slow decanting, and longer HRTs favoured floc formation and granule destabilization. During early operation, aerobic granulation was achievable without the presence of phosphate-accumulating organisms, provided that strong feast–famine conditions were maintained. This study highlights that AGS can be developed and maintained in low-strength wastewater and its potential application in municipal wastewater treatment plants.University of Manitoba Graduate Fellowship (UMGF), department of Civil EngineeringOctober 202
Genesis of the Rockstone graphite showing, Shebandowan Greenstone Belt, Western Superior Province, Canada
No full textBeyond its economic significance as a critical mineral, graphite provides valuable insights into the early carbon cycle and the environmental conditions of early Earth. The origin of graphite in Precambrian rocks has been a longstanding subject of interest in geological studies, owing to the possibility that it could represent remnants of early life on Earth. At the Rockstone property in Thunder Bay, Ontario, graphite occurs as very fine-grained particles (~10 to 80 μm) within late-stage chlorite–sulfide–quartz veins hosted by Neoarchean metasedimentary and metavolcanic rocks. Transmitted Electron Microscopy and Raman studies confirm that graphite is predominantly poorly crystalline and exhibits a turbostratic structure, which is indicative of deformation. Ti-in-biotite geothermometry yields peak amphibolite facies temperatures between ~500 and 565°C (±50°C). Raman temperatures of graphite are lower, varying from ~350 to 465°C (±50°C). Chlorite, interpreted to be in textural equilibrium with graphite, yields temperatures ranging from ~110 to 280°C (±20°C). In situ δ13CVPDB values of vein graphite ranges between -41.1 to -33.3‰ with a median of -36.7‰ (n=28) and indicates that the carbon is biogenic. In situ, sulfur isotope values (δ34SVCDT) of pyrite, sphalerite and pyrrhotite, vary from -0.5 to +6.7‰ with a median of +2.4‰ (n=55), which fall within the range characteristic of both metamorphic and igneous origins and are comparable to other sulfur isotope values of Archean VMS deposits in the Superior Province. Overall, our data indicates that organic matter was impacted by graphitization processes during regional metamorphism. Subsequently, vein graphite, highly depleted in 13C, might have formed from two main processes: (1) devolatilization of organic matter during low-grade metamorphism, and/or (2) migration from an existing graphite body at depth, during regional metamorphism. Alternatively, The Fischer-Tropsch (FT) reactions may have involved in the deposition of graphite at Rockstone. The occurrence of graphite within veins, closely associated with hydrous minerals such as chlorite and muscovite, as well as sulfide minerals, supports this interpretation.Republic of Turkey and its Ministry of National Education (https://yyegm.meb.gov.tr/)
University of Manitoba-C. H. R. Faculty of Env, Earth, and Resources Grad Entrance Scholar. (Award Number: 45525)
University of Manitoba-International Graduate Student Entrance ScholarshipOctober 202