https://knowledgecommons.lakeheadu.ca/handle/2453/6 2025-01-16t10:16:19z 2025-01-16t10:16:19z koornneef, karen https://knowledgecommons.lakeheadu.ca/handle/2453/5420 2025-01-16t10:01:40z 2024-01-01t00:00:00z

wetlands as filters of heavy metals: a study in temperate fens of central ontario koornneef, karen heavy metal concentrations (as, cd, cr, cu, ni, pb, and zn) were investigated in water, peat, and macrophytes across three fens in central ontario in relation to the water parameters and peat properties to elucidate the interactions between plant sequestration and heavy metal concentrations in the overlying water systems. the water parameters monitored include ph, dissolved oxygen, conductivity, total dissolved solids, salinity, nutrients, chlorophyll a, and dissolved organic matter. the peat properties studied included bulk density, volumetric porosity, and humification, and the plant properties studied included root length and the development of root plaques. in addition, all samples were analyzed for heavy metals. the fens were categorized from poor to rich depending on their water chemistry and plant community. surface water samples were collected from the inlet, outlet and midpoint of the fens in the spring, summer, and fall of 2023. porewater samples were collected from the midpoints of the fens using in situ pore water sampling device. in situ pore water sampling devices were deployed in the peat, and the porewater samples were collected from 10, 20 and 30 cm below the peat surface. peat cores were also collected in fall 2023 from the inlet and the midpoints of the fens to analyze the peat properties and heavy metal concentrations at three different depths (10, 20, and 30 cm below the peat surface). additionally, 13 plant species were collected in fall 2023 from the fens' midpoints and divided into upper and lower biomass for heavy metal analysis. [...]

2024-01-01t00:00:00z newhouse, douglas a. https://knowledgecommons.lakeheadu.ca/handle/2453/5419 2025-01-16t10:00:47z 2024-01-01t00:00:00z

do common over-the-counter antihistamine medications modify thermoregulatory responses during passive heat stress? newhouse, douglas a. over 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.

2024-01-01t00:00:00z mohammed, shakira https://knowledgecommons.lakeheadu.ca/handle/2453/5418 2025-01-15t10:00:48z 2024-01-01t00:00:00z

perfectionism from inside and outside: clarifying the role of intra- and interpersonal processes in predicting maladjustment using multi-source and intensive longitudinal methods mohammed, shakira life as a post-secondary student can be volatile and stressful, and illustrated by maladjustment (e.g., depressive symptoms). it is critical to understand factors that increase the risk for negative outcomes that can occur during this time. the current research examined dispositional perfectionism and interpersonal contexts as vulnerability factors for maladjustment in undergraduate 世界杯2022赛程表淘汰赛 using multi-source and intensive longitudinal methods (e.g., daily diaries). there is evidence that dimensions of perfectionism are specific vulnerability factors for maladjustment especially in the presence of congruent stressors. research also highlights the importance of investigating the perfectionism-maladjustment relationship within interpersonal contexts. in study 1, we tested the specific vulnerability hypothesis by assessing the extent to which socially prescribed perfectionism and self-oriented perfectionism impacted the stressfulness of congruent stressors (i.e., interpersonal stress and achievement stress, respectively), resulting in maladjustment among undergraduate 世界杯2022赛程表淘汰赛 . the targets (n = 296) from study 1, identified members of their social network (i.e., influencers) to participate in study 2. influencers (n = 720) reported on their own perfectionistic expectations to allow for an evaluation of targets’ interpersonal contexts. specifically, we tested an indirect effect of perfectionistic climate (reported by influencers) on targets’ maladjustment via targets’ socially prescribed perfectionism. we also evaluated the perfectionism social disconnection model, which suggests that interpersonal difficulties mediate the relationship between perfectionism and maladjustment. in study 1, the multilevel mixed models did not support the specific vulnerability hypothesis, although daily interpersonal stress and achievement stress predicted daily depressive affect. in study 2, path analyses showed that there were significant relations observed between targets’ socially prescribed perfectionism and maladjustment outcomes (e.g., stress, depressive symptoms, negative affect). there was no evidence to support the effect of the perfectionistic climate (reported by influencers) on targets’ maladjustment. lastly, there was partial support for the perfectionism social disconnection model, which suggested that targets’ interpersonal difficulties (e.g., poor social self-esteem) mediated the relationship between targets’ socially prescribed perfectionism and depressive symptoms. targets’ neuroticism emerged as an independent predictor of maladjustment across the analyses, further emphasizing the need to test models for incremental validity. this program of research addressed major methodological and statistical gaps in the literature and helped to inform strategies for prevention and intervention with undergraduate 世界杯2022赛程表淘汰赛 who might be struggling with unrealistic pressures for perfection and adjustment difficulties. specifically, a multilevel approach (e.g., individual, institutional) that emphasizes early mental health literacy, mental health curriculum in schools, individual intervention, and education for caregivers and professionals in educational and workplace settings is presented.

2024-01-01t00:00:00z ross, alexander john https://knowledgecommons.lakeheadu.ca/handle/2453/5417 2025-01-15t10:02:27z 2024-01-01t00:00:00z

influence of prey type and environment on lake trout (salvelinus namaycush) activity, mercury dynamics, and life histories ross, alexander john understanding food web structure in lentic ecosystems is a requirement for determining pathways and rates of energy flow, yet predator-prey interactions can be highly dynamic across space (i.e., between- and within-lakes) and time (e.g., diel daily cycles, seasonal). differences in prey availability can influence predator life history traits and behaviours, though life histories can also vary across environmental gradients. metabolic theory predicts that variation in prey and habitat availability affects metabolic rates by modifications to active behaviours, though the precise conditions controlling variation in activity have rarely been empirically assessed. further, the relative influence of activity via food web structure (compared with environmental characteristics) on life history traits and contaminant dynamics remain poorly understood. here, i integrate information regarding both prey availability and environmental factors to gain novel insights into their combined effects on lake trout activity, contaminant accumulation and life histories. using stationary hydroacoustics, i directly observed higher activity in planktivorous lake trout populations that exhibited sustained day-night swimming and higher active metabolism, which contrasted with piscivorous populations that had distinct day-night behavioural shifts, including nighttime rest. planktivorous lake trout maintained faster, more complex swimming paths, exhibited higher oxygen consumption, and were more frequently observed in suboptimal oxythermal conditions than piscivorous lake trout. secondly, lake trout mercury (hg) concentrations were affected by prey availability but not according to classical contaminant food chain length theory; rather, hg accumulation slopes against body size were more shallow when mysis diluviana was present than when they were absent, independent of overall food chain length. increasing dissolved organic carbon concentrations (doc) were also positively associated with lake trout hg, and the combined use of prey availability and doc proved essential for predicting whether lake trout hg concentrations exceeded canadian consumption guidelines for a given size. lastly, life history traits in lake trout were best explained by models combining both food web structure and environmental variables; adult length and size-at-maturity generally increased with greater prey availability, while environmental variables such as lake size and total phosphorus were key for describing trait variation within categories of prey availability. these findings provide empirical, field-validated support that prey availability can play as important of a role as environmental characteristics in shaping the life history traits of predatory fishes, like lake trout, through effects on activity, metabolic rates, and foraging opportunities.

2024-01-01t00:00:00z