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Development of an ice-jam flood forecasting modelling framework for freeze-up/winter breakup
No full textThis is an Open Access article distributed under the terms of the Creative Commons Attribution Licence (CC BY 4.0), which permits copying, adaptation and redistribution, provided the original work is properly cited (http://creativecommons.org/licenses/by/4.0/).Global Water Future program at the Global Institute for Water Security, University of SaskatchewanPeer ReviewedRiver ice-jams can create severe flooding along many rivers in cold regions. While ice-jams often form during the spring breakup, the midwinter breakup can cause ice-jamming and flooding. Although many studies have already been focused on forecasting spring ice-jam flooding, studies related to forecasting mid-winter breakup jamming and flooding severity are sparse. The main purpose of this research is to develop a stochastic framework to forecast the severity of mid-winter ice-jam flooding along the transborder (New Brunswick/Maine) Saint John River of North America. A combination of hydrological (MESH) and hydraulic model (RIVICE) simulations was applied to develop the stochastic framework. A mid-winter breakup along the river that occurred in 2018 has been hindcasted as a case study. The result shows that the modelling framework can capture the real-time ice-jam severity. The results of this research will help to improve the capacity of ice-jam flood management in cold regions
Monte Carlo Simulation and Experimentation of Non-Collinear Gamma Ray Correlations as a Novel Medical Imaging Modality
No full textThis thesis describes the simulation, experiment, and image analysis of a new modality of nuclear medical imaging. We propose the measurement of cascade gamma rays emitted by radioactive isotopes as an improvement over conventional Positron Emission Tomography (PET) and Single Photon Emission Computed Tomography (SPECT). This modality employs the coincidence detection of non-collinear cascade gamma rays as a means to perform event-by-event image reconstruction. This is unlike PET and SPECT, which require multiple events to locate the image point as they lack depth information of the photon trajectories. Our modality can be considered a marriage of PET and SPECT imaging as it employs coincidence techniques as in PET and collimation as in SPECT.
For the prototype experiment, we employed In-111 (2.8 days half-life). with a pair of high-intensity cascade gamma rays of energies Eγ1 = 171 keV and Eγ2 = 245 keV. We performed the measurement using the small-animal PET machine of the Institute of Physical and Chemical Research in Kobe, Japan (RIKEN-BDR). We employed Geant4 Application of Tomographic Emission (GATE) public domain software for the simulation and design of the collimators. We had them built at the Physics Machine Shop of the University of Saskatchewan.
We employed the cascade emissions of Ba-133 (half-life=10.5 years) for calibration purposes, procured the In-111 source from suppliers to RIKEN-BDR, and performed the measurements in the summer of 2022. We carried out the measurements for single and multiple point-like source arrangements. We have successfully performed the image reconstruction with the use of individual decay events in the coincidence detection.
The results are quite promising, as the image reconstruction and image resolutions are comparable to those of conventional PET images without resorting to involved statistical algorithms. The sources used were <5 MBq and measurements were taken for 2 to 15 hours. Thus, it seems this new modality offers promise of utility for molecular imaging applications. In conclusion, the thesis suggests the next steps in this direction
3D Printed Polycaprolactone/Nano-Hydroxyapatite Scaffolds for Bone Tissue Engineering In-Vitro
No full textThe abstract of this item is unavailable due to an embargo
Evaluation of a Pilot-Scale Electro-nanospray System for Decontaminating Pig Barns
No full textExposure to bioaerosols, noxious gases, and high dust concentrations in confined livestock facilities have been linked to human and animal health hazards, with consequent adverse economic implications. In this study, an electro-nanospray system was developed for pig barn decontamination. This technology generates engineered water nanostructures (EWNS) through electrospraying and ionization of reverse osmosis (RO) water. The highly charged nano-scale water droplets encapsulate reactive oxygen species (ROS), which are responsible for bacterial inactivation and for capturing particulate matter through electrostatic forces.
Prior to testing the nanospray under actual swine barn environment, laboratory-scale experiments on bioaerosol deactivation were conducted using an acrylic chamber in which the electro-nanospray system was installed. Based on the deactivation efficacies of 16 needle spray injectors, the determined air flow rate obtained through theoretical calculation was 10 air changes per hour (ACH), which resulted in 49.3% bacterial reduction when Escherichia coli was dispersed as test bioaerosol pathogen inside the chamber. Furthermore, laboratory results using the developed nanospray with varying number of needle spray injectors indicated that 16 is the determined number of needle injectors for the volume of the test chamber used based on reduction efficiency. Surface decontamination with nanospray showed about 71%, 64%, 59%, and 51% reduction efficiency on plastic, metal, wood, and concrete surfaces, respectively.
In the in-barn experiments, one nano-spray treatment chamber was installed in the preliminary trial, while two units were installed in Trials 1 and 2. Results showed an average of 59% (preliminary trial) and 56% (Trials 1 and 2) reduction in bioaerosols in the airstream flowing through the nano-spray treatment chamber installed in the Treatment room. Preliminary trial showed that no measurable impact was observed on bioaerosol concentrations, while dust concentrations was reduced by an average of 28%. For Trials 1 and 2, results showed better effectiveness on culturable bacteria and dust concentrations with an average reduction of 31% and 42%, respectively. During the trial period, a higher increase in ammonia and carbon dioxide concentrations was observed in the Control room compared to the Treatment room, while surface decontamination showed about 46%, 36%, 31%, and 29% reduction efficiency on concrete, metal, wood and plastic surfaces, respectively. No significant difference in pig performance was observed between the two experimental rooms
Beyond Orthomosaics: A comparison of orthomosaic versus original aerial images for high-throughput phenotyping
No full textImagery from Unoccupied Aerial Vehicles (UAVs) is frequently used for remote crop assessment and phenotyping in agricultural research. In particular, spectral indices such as the Normalized Difference Vegetative Index (NDVI), are commonly employed to estimate traits such as the health, growth stage, and biomass in crops. In virtually all such studies, many overlapping images from a UAV flight are first stitched into a single orthomosaic image, and then spectral indices are derived from the orthomosaic. This method necessarily discards (or aggregates) much of the original pixel information. For example, a single plot may appear in 10 or more individual images from the UAV, but appear only once in the final orthomosaic. In this research, we show that an NDVI value extracted from individual calibrated images of the same plot can deviate by up to 0.05 from the NDVI value of the corresponding orthomosaic segment. This could have important consequences for fine-grained comparison of indices. To address this problem, we propose alternative approaches to estimating indices, each of which more directly incorporates all of the individual UAV images. We evaluate these approaches, and compare them with the orthomosaic approach, by analyzing weekly index values from plant breeding experiments for lentil, wheat, and canola crops in comparison to relevant manually-measured phenotypes
Altering the essential amino acid-nitrogen:total nitrogen ratio with ammonium phosphate impacts nitrogen retention, lysine requirement and body composition of growing pigs
No full textLow protein (LP) diets have improved nitrogen (N) utilization while maintaining the performance of growing pigs. Regardless, LP diets may be limiting in N content to meet non-essential amino acid (NEAA) requirements, which may alter essential amino acid (EAA) utilization and requirements, as well as animal growth. Inclusion of a source of non-protein N (NPN) may be beneficial for improving utilization of EAA for lean gain in LP diets. Therefore, this thesis evaluated the effects of providing no NPN supplementation (NAP) or 1.7% NPN inclusion (AP) in an N-deficient diet, as indicated by a high EAA-N:total N ratio (EAA-N:TN) on the lysine (Lys) requirement for N retention (NR) and growth performance in pigs. An N balance study estimated 1.09% SID Lys requirement to maximize NR in NAP-fed pigs (EAA-N:TN of 0.36), while a 1.00% standardized ileal digestible (SID) Lys requirement was determined in AP-fed pigs (EAA-N:TN of 0.33). This result indicates that N is limiting in LP diets, and that Lys requirement and NR are greater with NPN supplementation. A subsequent growth performance study was conducted using the same dietary factor of NPN inclusion. Lysine content was based on NRC (2012) requirement and breakpoint values from the N-balance study and formulated for 20-40kg pigs. Average daily gain (ADG), average daily feed intake (ADFI), gain:feed (G:F), N output and carcass characteristics were assessed. Overall ADG and d 28 BW were improved with increasing Lys content, while G:F and lean depth were greater with NPN inclusion. Fecal N output was increased with NPN supplementation. Overall, N may be limiting in LP diets and ammonium phosphate is a suitable source of N for growing pigs, improving NR and maintaining growth in pigs fed diets deficient in NEAA-N. By improving the efficiency of N utilization and our knowledge of the importance of N to growing pigs, nutritionists will further improve diet formulation to reduce N excretion, diet costs and improve overall swine production
Flow Around Isolated and Tandem Surface-Mounted Finite-Height Square Prisms of Small Aspect Ratio
No full textThe abstract of this item is unavailable due to an embargo
Seasonal Weather Effects on Mass Variation and Torpor Expression in an Obligate Hibernator
Get PDFGlobal climate change, characterized by long term changes in temperature and precipitation patterns, can present an energetic challenge to terrestrial species. Seasonal hibernators are potentially vulnerable to projected changes because their annual energy management is tightly connected to predictable fluctuations in environmental resources. I studied the relationships between environmental factors and seasonal energy management in a wild population of Columbian ground squirrels (Urocitellus columbianus) between 2009 and 2020. I hypothesized that vegetation availability and torpor expression mediated the direct relationships between weather (i.e., temperature and precipitation) and ground squirrel energy budgets (measured as seasonal mass variation). I found that separate weather patterns influenced summer mass gain for each sex immediately following reproductive investment. As measured, vegetation availability did not significantly influence the total summer mass gain of either sex. Males lost more mass in cold winters (-11.49 1.64 g body mass/1°C decrease in mean air temperature between Oct 2 and Mar 28), but female mass loss was more strongly influenced by entry mass and emergence phenology than winter weather.
I conducted a two-way factorial field experiment to test the influences of entry mass and hibernation microclimate on torpor expression and over-winter mass loss. I manipulated pre-hibernation entry mass by supplementally feeding a treatment group of females prior to hibernation. On average, fed females weighed 40 g more than unfed females entering hibernation (fed mean mass 567 51 g, unfed mean mass 527 40 g, t25 = 2.33, df = 25.09, p = 0.03) . I manipulated the hibernation microclimates of a treatment group containing fed and unfed females by installing snow fences upwind of their hibernacula. The snow fences created deep snowpack, which raised and stabilized the ambient temperature of the hibernacula compared to females hibernating without snow fences. Females in colder hibernacula increased torpor expression (e.g., expressed colder torpid skin temperatures, Tsks), but females with larger pre-hibernation energy stores reduced torpor expression. Thus, warmer winters may reduce hibernation thermoregulatory costs and allow large ground squirrels to invest energy in torpor reduction. This study shows that the effects of projected climate changes on seasonal hibernator energy management will have complex and opposing effects for separate demographic classes depending on when the changes occur within the calendar year
“I Don't Know What is HPV or ABC”: Perspectives on the Barriers to and facilitators of Human Papillomavirus Vaccine Uptake at Three Levels across Saskatchewan -- Patient-, Provider-, and System-Level.
No full textThe abstract of this item is unavailable due to an embargo
Determinants of The Return on Cryptocurrencies
No full textThe abstract of this item is unavailable due to an embargo