HARVEST
University of Saskatchewan's Repository for Research, Scholarship, and Artistic Work
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ECOLOGICAL CONSEQUENCES OF INTRASPECIFIC VARIATION IN ENERGY ALLOCATION PATTERNS IN COLUMBIAN GROUND SQUIRRELS (UROCITELLUS COLUMBIANUS)
(2025-01-20) Guerrero Chacon, Adriana Lucia; Lane, Jeffrey Edward; Wiebe, Karen Lorelle; Marchant, Tracy; Unniappan Moothathu, Suraj
Energy is a temporally and spatially limited resource, often regarded as the currency or the “fire of life”. In highly seasonal environments with fluctuating food availability and climatic conditions, individuals must carefully match energy acquisition, allocation, and the timing of energy demanding activities to maximize fitness. However, considerable intraspecific variation exists in how energy is acquired and used, as well as in the timing of costly activities such as reproduction and growth. Hibernating mammals are a unique system to study how intraspecific variation in energetics and phenological traits influences life history, as their brief active season requires them to obtain enough energy for reproduction, growth, and overwinter survival within a limited period. Columbian ground squirrels (Urocitellus columbianus) have a short active season of 3-4 months, during which adults must meet the energy demands of breeding, moulting, survival, and fattening prior to hibernation. Females finance reproduction primarily through daily income (by increasing their foraging rate), but also rely on capital resources (through endogenous fat stores), likely beginning the season with varying amounts of fat stores, which could influence how they allocate their energy throughout reproduction. In contrast, juveniles have an active season of only 1.5 to 2 months, likely facing energetic trade-offs between investing in structural growth and accumulating sufficient fat reserves to survive hibernation. In this thesis, I investigated how intraspecific variation in energetic (e.g., metabolic rates, body composition) and phenological traits (e.g., timing of parturition) in Columbian ground squirrels influences key life history traits, such as female reproductive output, juvenile growth, and survival. To do so, I used a multi-disciplinary approach that combined long-term ecological data, as well as physiological measurements, and targeted food supplementation. I found that different life history traits within the same system may support different models of energy allocation. The positive and significant associations between resting metabolic rate (RMR), daily energy expenditure (DEE), and reproductive output during lactation aligned with the predictions of the performance model, whereas the lack of a significant association between RMR and post-weaning growth aligned more closely with the predictions of the independent model of energy allocation. Additionally, I found that even slight differences in parturition timing significantly influenced juvenile body mass and growth trajectories. While females did not compensate for late breeding by increasing juvenile body mass at birth, they did show compensatory adjustments during lactation, resulting in higher body masses at weaning for late-born offspring. However, late born juveniles did not exhibit compensatory growth after weaning, nor did they extend their growth period which may underlie the decline in annual fitness among late emerging females reported in previous studies. The supplemental food treatment significantly influenced energy allocation on both reproductive females and juveniles. For females, it increased capital resources before reproduction, leading them to rely more on fat stores during gestation. In juveniles, the treatment enhanced post-weaning growth rates, extended growth duration, increased asymptotic body mass, and enhanced fat accumulation. Overall, this research advances our understanding of energy use and allocation in wild mammals, providing valuable insights into how environmental factors (such as resource availability), maternal investment, and metabolic rates contribute to intraspecific variation in life history traits.
Development and Testing of Selective and Differential Media for the Recovery of Bacterial Bovine Respiratory Disease Isolates from Feedlot water Bowls
(2025-01-20) Wadt, Danilo; Jelinski, Murray D; Ruzzini, Antonio; Snyder, Emily; Wood, Sarah; Palmer, Colin
Bovine respiratory disease (BRD) is a significant disease of both beef and dairy cattle production, influenced by various factors including stressful conditions, viral and bacterial pathogens, and management practices. The four main bacterial species associated with BRD, Pasteurella multocida, Mannheimia haemolytica, Histophilus somni, and Mycoplasmopsis bovis, have predominantly been studied using isolates obtained from sick and dead cattle. Antimicrobial usage (AMU) has been used for both metaphylactic and prophylactic control of BRD, contributing to the rise in antimicrobial resistance (AMR) within these production systems. Traditionally, AMR evaluation has focused on antimicrobial susceptibility testing (AST), but there has been a shift towards screening via molecular methods. Exploring alternative methods for AMR screening utilizing environmental fomite isolates could inform timely management decisions. Water bowls serve as promising targets for isolating these bacterial pathogens because bacteria appear to be shed into the water from the animal’s upper respiratory tract (URT). Shared water bowls have also been identified as a significant risk factor for BRD in feedlot cattle. The isolation of BRD pathogens from water bowls is challenging due to their fastidious nature and overgrowth by more competitive environmental microbes.
The overarching objective was to develop culture media to aid in the recovery of P. multocida, M. haemolytica, and H. somni from feedlot water bowls. These isolates could then be used to monitor AMR at the feedlot pen level. To achieve this goal, the project was divided into four separate objectives: 1) characterize the metabolic profiles of the three Pasteurellaceae pathogens for identification of potential nutritional requirements and differentiation targets; 2) develop and test both chemically defined (CDM) and differential media (DM) using Pasteurellaceae isolates; 3) assess CDM and DM for the isolation of P. multocida and M. haemolytica from feedlot water bowl samples; and 4) characterize the antimicrobial resistance (AMR) phenotypes and genotypes of M. bovis isolates obtained from feedlot water bowls and cattle that died of BRD.
Initially, biochemical characterization was performed with P. multocida, M. haemolytica and H. somni, using 189 organic compounds, 96 solute concentration conditions, and 96 pH conditions. All three BRD pathogens effectively metabolized L-cysteine. P. multocida uniquely metabolized L-glutamic acid and mannose, while M. haemolytica metabolized L-aspartic acid and maltose. Whereas H. somni metabolized L-arabinose and D-glucosamine, the fastidious nature of the organism required additional nutritional supplements. These metabolization studies helped to inform the development of a CDM and DM for P. multocida and M. haemolytica.
Next, a CDM for P. multocida was developed from a M9 mineral salt base, L-cysteine, L-glutamic acid, and mannose. The CDM for M. haemolytica was comprised of L-cysteine, L-leucine, and maltose. A DM was also developed, with the differentiation factor being the fermentation of mannose for P. multocida, and maltose for M. haemolytica along with a pH indicator. Both the CDM and DM were able to sustain the growth of their respective bacterial species. All CDM required a high initial bacterial inoculum for sustained growth, while the DM supported bacterial growth at low initial concentrations. The morphology of the colonies in CDM was not visually discernible from other bacteria. In contrast, colonies in the DM were dark yellow, small, regular, and glistening, and allowed visual discernment from other bacteria. The CDM and DM were then used for isolating P. multocida and M. haemolytica from feedlot water bowls.
Both DM were tested with feedlot water bowl samples collected between September and November 2023, using a total of 120 samples collected over 9 weeks. Putative colonies of P. multocida (300) and M. haemolytica (256) were screened by PCR, but all were negative for P. multocida and M. haemolytica. However, by using a previously described and well documented selective medium for Mycoplasmataceae organisms, 67 M. bovis isolates, confirmed by PCR, were recovered and underwent AST with 10 antimicrobials. All (100%) of the isolates were resistant to macrolides (MIC >64 ug/mL) and florfenicol (MIC > 8 ug/mL); 87% to oxytetracycline (MIC > 4 ug/mL); and 77% to gentamycin (MIC > 8 ug/mL). Approximately 30% of isolates had MIC > 2 ug/mL for enrofloxacin. Genomic analysis identified known resistance-associated mutations in 25 isolates, indicating common resistance mechanisms between water bowl-borne isolates and lung sample isolates. These results suggest the possibility of using environmentally sourced isolates as an alternative for AMR screening in feedlot operations.
OIL PRICE SHOCKS AND NONPERFORMING LOANS IN THE UNITED STATES OF AMERICA
(2025-01-20) Alizadeh tabatabaie, Saeed; Mamum, Abdullah; Tannous, George; Maung, Min; Asem, Ebenezer
This study examines the effects of oil price shocks on non-performing loans (NPLs) in U.S. banks from 1995 to 2023, with an emphasis on the distinct impacts across oil-producing and non-oil-producing states. Using the Ready (2018) framework, oil price fluctuations are decomposed into demand shocks, supply shocks, and risk shocks to analyze their respective influences on NPL levels. The findings indicate that oil demand shocks, reflecting increased economic activity, reduce NPL levels, whereas oil supply shocks, which elevate input costs without stimulating the economy, lead to higher NPLs. Furthermore, oil-producing states exhibit greater resilience to oil supply shocks due to their ability to capitalize on increased oil revenues, in contrast to non-oil-producing states. This study underscores the importance of differentiating between the sources of oil price shocks to better understand their implications for financial stability.
Sustainable agro-waste pellets as granular slow-release fertilizer carrier systems for ammonium sulfate
(Royal Society of Chemistry, 2024) Steiger, Bernd; Bui, Nam; Babalola, Bolanle; Wilson, Lee
In this study, several granular biocomposite carrier systems were prepared that contain biomaterials (chitosan, torrefied wheat straw and avian eggshells) as additive components at variable composition. The biocomposites were loaded with ammonium sulfate (AS) by two methods: (1) in situ addition of AS during pellet preparation, and (2) an adsorption method of AS after pellet preparation. Characterisation was carried out via spectroscopy (XRD, FT-IR) and complementary methods (TGA, acid stability). The pellet system (C1) by method (1) contained ca. 22 mg per g NH4+, whereas pellet systems by method (2) contained up to ca. 40 mg per g NH4+. The mol-ratio of NH4+ : SO42− varied from 2.18 (C1) to 2.72 (CW72), 2.97 (CW20), 2.64 (CW21) and 3.20 (CW22). Release studies in water showed that C1 pellets released almost 100% NH4+ within 3 h, while release varied from ca. 60% (CW72), ca. 40% (C20), 20% (C21) to 10% (CW22). By comparison, the systems prepared through method (2) showed a marginal increase of the release profiles up to 96 h. Granular AS carrier systems prepared by method (2) displayed greater mechanical stability and AS content versus the systems prepared by method (1). We demonstrated the ability to tailor the physico-chemical properties of such biocomposite carriers and highlight their promising potential as slow-release fertilizer systems.
Exploring energy transition narratives through mayoral insights using artificial intelligence
(Elsevier, 2024-12-21) Ahmed, Fatma; Ahmed, Rwan; Poelzer, Greg; Poelzer, Gregory; Söderberg, Charlotta; Zapata, Oscar; Guilmette, Elaina
This paper explores energy transition dynamics in three Arctic cities: Luleå (Sweden), Fairbanks (Alaska), and Yellowknife (Canada), with a focus on sustainable urban development. Semi-structured interviews with the mayors of these cities provide insights into their decision-making processes and strategies regarding energy transitions. Using Natural Language Processing (NLP) for semantic analysis, the study uncovers implicit priorities, challenges, and aspirations from the qualitative data. The analysis is guided by the theory of planned behavior, which helps to explain the underlying motivations, attitudes, and perceived behavioral control that influence policy decisions. Results reveal common themes such as balancing environmental goals with economic and social concerns, while also highlighting context-specific challenges in each city. This research contributes to the understanding the role of municipal leadership in energy transitions and demonstrates the effectiveness of NLP techniques in extracting meaningful insights from interviews. The findings aim to inform policymakers and urban planners on fostering sustainable energy transitions in Arctic regions.
Climate Driven Trends in Historical Extreme LowStreamflows on Four Continents
(Wiley, American Geophysical Union, 2024-06-17) Hodgkins, Glenn; Renard, Benjamin; Whitfield, Paul; Laaha, Gregor; Stahl, Kerstin; Hannaford, Jamie; Burn, Donald; Westra, Seth; Fleig, Anne; Lopes, Walszon Terllizzie Araújo; Murphy, Conor; Mediero, Luis; Hanel, Martin
Understanding temporal trends in low streamflows is important for water management and ecosystems. This work focuses on trends in the occurrence rate of extreme low-flow events (5- to 100-year return periods) for pooled groups of stations. We use data from 1,184 minimally altered catchments in Europe, North and South America, and Australia to discern historical climate-driven trends in extreme low flows (1976–2015 and 1946–2015). The understanding of low streamflows is complicated by different hydrological regimes in cold, transitional, and warm regions. We use a novel classification to define low-flow regimes using air temperature and monthly low-flow frequency. Trends in the annual occurrence rate of extreme low-flow events (proportion of pooled stations each year) were assessed for each regime. Most regimes on multiple continents did not have significant (p < 0.05) trends in the occurrence rate of extreme low streamflows from 1976 to 2015; however, occurrence rates for the cold-season low-flow regime in North America were found to be significantly decreasing for low return-period events. In contrast, there were statistically significant increases for this period in warm regions of NA which were associated with the variation in the Pacific Decadal Oscillation. Significant decreases in extreme low-flow occurrence rates were dominant from 1946 to 2015 in Europe and NA for both cold- and warm-season low-flow regimes; there were also some non-significant trends. The difference in the results between the shorter (40-year) and longer (70-year) records and between low-flow regimes highlights the complexities of low-flow response to changing climatic conditions.
The 2021 heatwave results in simultaneous but different hydrological responses over Canada west of 100◦W
(Journal of Hydrology, 2024-02) Whitfield, Paul H; Abdelmoaty, Hebatallah; Nerantzaki, Sofia; Papalexiou, Simon Michael
The 2021 Western North America heatwave resulted in record high air temperatures over a large area of Canada west of 100°. The heatwave persisted from mid-June into July, depending upon the threshold used to define the heatwave. The heatwave was a weather event that was short lived but had a widespread transient impact on hydrology in this single year. These impacts were more evident in nival systems because of the prominent role of snowmelt. In normal years, the timing of hydrological processes, particularly snowmelt, is a function of latitude and elevation; in 2021 the heatwave resulted in simultaneous high rates of snowmelt across rivers where a snowpack existed at the time of the event, and strong diurnal melt signal was a diagnostic. In 2021, rivers throughout Canada west of 100°W responded strongly to the heatwave, but the response depended on three factors: location relative to the heat dome, the hydrologic regime, and the amount of snow present at the time. The melt signal was strongest in those basins that had not reached their annual peak often having discharges in the highest 5 % of historical observations for that day of the year. Discharges rapidly declined in basins already in recession indicating the rapid depletion of the snowpack. In basins with little or no remaining snow, streamflow often declined during the same period often to levels in the lowest 5 % of historical observations for that day of the year.
Conditional cross-correlation analysis of floating potential fluctuations in the TJ-II stellarator
(Radiation Effects and Defects in Solids, 2024-12-31) Bsharat, H
Voldiner, Igor
van Milligen, B. Ph
Xiao, C
The conditional nonlinear cross-correlation technique has been used to analyze the floating potential fluctuations measured by a radially distributed rake probe array during the electrode biasing experiments on the TJ-II stellarator. Preliminary results suggest that the propagation direction of the turbulence energy changes from outwards in the case without biasing to inwards when biasing is applied.
Effect of modified intravascular laser irradiation of blood in the oral and systemic conditions during dental treatment—A systematic review
(Lasers in Medical Science, 2024-12-20) Oliveira, Maria Clara; Filipe Bezerra Silva, Diego; Andrade, Allany; Pita de Melo, Daniela; de Sousa, Ygor Alexandre Beserra; da Silva, Luís Otávio Pereira; Gomes, Daliana
The aim of this study was to investigate the scientific evidence regarding the effectiveness of modified-ILIB (intravascular laser irradiation of blood) in the control of systemic conditions and/or oral changes during dental care. This systematic literature review study aimed to answer the question, "Is modified-ILIB an effective adjuvant therapy in the control of systemic conditions and/or oral changes in children and adults during dental treatment?". The protocol for this systematic review was registered in the PROSPERO database under number CRD42023493800. The search was carried out in the PubMed, Web of Science, LILACS, SCOPUS and EMBASE databases on June 10, 2024. Google Scholar was used as a search source for gray literature. Randomized clinical trials were included, without restrictions on language or year of publication. The RoB 2.0 tool was used to assess the risk of bias and GRADE was used to check the quality of the evidence. A total of 750 articles were retrieved and five studies were selected for this review. All studies were in English and were carried out in Brazil. The outcomes were periodontal parameters and glycemic control in patients with periodontitis and type II diabetes, anxiety control in pediatric dentistry, postoperative pain after third molar extraction and improving taste in post-COVID-19 patients. The majority of studies had a low risk of bias, while only one study was considered to have some concerns. The quality of evidence from the studies was considered very low. The current evidence does not overwhelmingly support the effectiveness of modified-ILIB in controlling oral and/or systemic conditions in dentistry.
Comparison of flea diversity in the burrows of Richardson’s ground squirrels (Urocitellus richardsonii) in an urban and rural site in central Saskatchewan, Canada
(Journal of Vector Ecology, 2024-09-20) Thoroughgood, Jessica T; Chilton, Neil B
Spatial and temporal differences in the relative abundance of arthropod vectors is an important factor influencing the risk of disease for mammalian hosts. Seasonal changes in the diversity and abundance of fleas (Siphonaptera) in Richardson's ground squirrel (Urocitellus richardsonii) burrows were studied at two sites in central Saskatchewan. A total of 225 fleas (151 at an urban site and 74 at a rural site) were collected. Flea prevalence differed among seasons at the urban site, but not at the rural site. Of the nine flea species detected (8 at the urban site and 6 at the rural site), Oropsylla rupestris, O. bruneri, O. labis, O. tuberculata and Aetheca wagneri are vectors of Yersinia pestis, the causative agent of plague. The presence and abundance of some fleas differed between sites and seasons. Neopsylla inopina and O. rupestris were the most abundant species at the urban site during the spring and summer (respectively), while O. bruneri was the most abundant species at the rural site. Our findings may have implications for the management of the black-tailed prairie dogs (Cynomys ludovicianus) in south-western Saskatchewan because they coexist with U. richardsonii, are hosts for Oropsylla, and are at great risk of plague exposure/infection.