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OPUS: Open Ulethbridge Scholarship

Open ULeth Scholarship (OPUS) is the University of Lethbridge's open access research repository. It contains a collection of materials related to research and teaching produced by the academic community.

Self-archiving your research in OPUS is one way to meet Open Access policies of granting agencies. It is important to retain your final, post-peer-reviewed drafts for submission to OPUS, as this is often the only version publishers will allow to be archived. Click here for information on the U of L Open Access Policy.

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    The anti-inflammatory effects of Cannabis sativa extracts on LPS-induced cytokines release in human macrophages
    (MDPI, 2023) Zaiachuk, Mariia; Suryavanshi, Santosh V.; Pryimak, Nazar; Kovalchuk, Igor; Kovalchuk, Olga
    Inflammation is the response of the innate immune system to any type of injury. Although acute inflammation is critical for survival, dysregulation of the innate immune response leads to chronic inflammation. Many synthetic anti-inflammatory drugs have side effects, and thus, natural anti-inflammatory compounds are still needed. Cannabis sativa L. may provide a good source of anti-inflammatory molecules. Here, we tested the anti-inflammatory properties of cannabis extracts and pure cannabinoids in lipopolysaccharide (LPS)-induced inflammation in human THP-1 macrophages. We found that pre-treatment with cannabidiol (CBD), delta-9-tetrahydrocannabinol (THC), or extracts containing high levels of CBD or THC reduced the level of induction of various cytokines. The CBD was more efficient than THC, and the extracts were more efficient than pure cannabinoids. Finally, IL-6, IL-10, and MCP-1 cytokines were most sensitive to pre-treatments with CBD and THC, while IL-1β, IL-8, and TNF-α were less responsive. Thus, our work demonstrates the potential of the use of cannabinoids or/and cannabis extracts for the reduction of inflammation and establishes IL-6 and MCP-1 as the sensitive markers for the analysis of the effect of cannabinoids on inflammation in macrophages.
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    The invisibilization of death: accounting for migrant deaths along the Canada-US border
    (Sage, 2026) Young, Julie E. E.; Martinez, Daniel E.; Granovsky-Larsen, Simon; Simburger, Dylan; Williams, Kira; Silva, Caroline Cordeiro V.
    Irregular migration at the Canada-US border, along with associated dangers, has received increased attention since the implementation of the Canada-US Safe Third Country Agreement. Reports by non-governmental organizations highlight the lethality of irregular migration at this border. Nevertheless, not only do reports fail to provide estimates of migrant fatalities, but there are also no official data sources on deaths produced by authorities in either country. Using this silence as a starting point, we ask: How many migrants perish while crossing the Canada-US border? To what extent, if at all, are US and Canadian officials tracking border-crosser deaths in this region? What can we learn from media reporting on this issue? We addressed these questions by (1) submitting public records requests to federal authorities in Canada and the United States, and (2) conducting an exhaustive search of media coverage on migrant deaths published by Canadian and US newspapers. Records requests resulted in just one migrant fatality recorded by the Royal Canadian Mounted Police. Yet, media reports confirmed 40 migrant fatalities, which most likely constitute an undercount. Given the overall underwhelming attention paid to deaths at the Canada-US border, we conclude by discussing the factors contributing to the lack of visibility of this ongoing human tragedy. Considering our study’s findings, we provide the following policy recommendations: ● The federal governments of the United States and Canada should create a classification system—like the one utilized by the Pima County Office of the Medical Examiner in Tucson, Arizona—that local officials in jurisdictions along the Canada-US border could use to categorize decedents as suspected irregular border-crossers. ● Increased communication, collaboration, and transparency between local authorities involved in the investigation of migrant fatalities at the Canada-US border and federal immigration officials in both countries. For example, authorities should liaise with their counterparts on the other side of the border for any migrant fatality investigation. We suggest the establishment of a working group modeled on the informal Working Group on Accounting for Migrant Deaths along the US-Mexico Border. ● Address jurisdictional challenges in the Canadian context that lead to a vacuum of official accountability in tracking migrant fatalities on Canadian territory and report on migrant fatalities at the border on an annual basis. For example, our research suggests that officials at the national headquarters of the Royal Canadian Mounted Police (RCMP) do not have access to data about fatalities investigated by their local detachments across the country. Migrant deaths at the Canada-US border are likely investigated by a range of agencies, including RCMP and local police forces that may be administered by provincial, municipal, and Indigenous governments. ● The US Missing Persons and Unidentified Remains Act of 2019, which is public law, requires that US Customs and Border Protection (CBP) annually report to the US Congress the number and location of migrant fatalities that occur at the U.S.-Mexico border, and that these estimates be disclosed publicly within 30 days of each reporting period, the latter of which CBP currently does not do. The Missing Persons and Unidentified Remains Act should be amended to include migrant fatalities at the US-Canada Border. Furthermore, CBP should adjust its public reporting of deaths at the US-Mexico border to comply with the law.
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    A bio-economic case study of Canadian honey bee (Hymenoptera: Apidae) colonies: marker-assisted selection (MAS) in queen breeding affects beekeeper profits
    (Oxford University Press, 2017) Bixby, Miriam; Baylis, Kathy; Hoover, Shelley E.; Currie, Robert W.; Melathopoulos, Andony P.; Pernal, Stephen F.; Foster, Leonard J.; Guarna, M. Marta
    Over the past decade in North America and Europe, winter losses of honey bee (Hymenoptera: Apidae) colonies have increased dramatically. Scientific consensus attributes these losses to multifactorial causes including altered parasite and pathogen profiles, lack of proper nutrition due to agricultural monocultures, exposure to pesticides, management, and weather. One method to reduce colony loss and increase productivity is through selective breeding of queens to produce disease-, pathogen-, and mite-resistant stock. Historically, the only method for identifying desirable traits in honey bees to improve breeding was through observation of bee behavior. A team of Canadian scientists have recently identified markers in bee antennae that correspond to behavioral traits in bees and can be tested for in a laboratory. These scientists have demonstrated that this marker-assisted selection (MAS) can be used to produce hygienic, pathogen-resistant honey bee colonies. Based on this research, we present a beekeeping case study where a beekeeper’s profit function is used to evaluate the economic impact of adopting colonies selected for hygienic behavior using MAS into an apiary. Our results show a net profit gain from an MAS colony of between 2% and 5% when Varroa mites are effectively treated. In the case of ineffective treatment, MAS generates a net profit benefit of between 9% and 96% depending on the Varroa load. When a Varroa mite population has developed some treatment resistance, we show that MAS colonies generate a net profit gain of between 8% and 112% depending on the Varroa load and degree of treatment resistance.
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    Multisensor and multispectral LiDAR characterization and classification of a forest environment
    (Taylor & Francis, 2016) Hopkinson, Christopher; Chasmer, Laura; Gynan, Chris; Mahoney, Craig; Sitar, Michael
    Airborne LiDAR is increasingly used in forest carbon, ecosystem, and resource monitoring. For practical design and manufacture reasons, the 1064 nm near-infrared (NIR) wavelength has been the most commonly adopted, and most literature in this field represents sampling characteristics in this wavelength. However, due to eye-safety and application-specific needs, other common wavelengths are 1550 nm and 532 nm. All provide canopy structure reconstructions that can be integrated or compared through space and time but the consistency or complementarity of 3D airborne LiDAR data sampled at multiple wavelengths is poorly understood. Here, we report on multispectral LiDAR missions carried out in 2013 and 2015 over a managed forest research site. The 1st used 3 independent sensors, and the 2nd used a single sensor carrying 3 lasers. The experiment revealed differences in proportions of returns at ground level, vertical foliage distributions, and gap probability across wavelengths. Canopy attenuation was greatest at 532 nm, presumably due to leaf tissue absorption. Relative to 1064 nm, foliage was undersampled at midheight percentiles at 1550 nm and 532 nm. Multisensor data demonstrated differences in foliage characterization due to combined influences of wavelength and acquisition configuration. Single-sensor multispectral data were more stable but demonstrated clear wavelength-dependent variation that could be exploited in intensity-based land cover classification without the aid of 3D derivatives. This work sets the stage for improvements in land surface classification and vertical foliage partitioning through the integration of active spectral and structural laser return information.
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    Estimating canopy gap fraction using ICESat GLAS within Australian forest ecosystems
    (MDPI, 2017) Mahoney, Craig; Hopkinson, Christopher; Kljun, Natascha; van Gorsel, Eva
    Spaceborne laser altimetry waveform estimates of canopy Gap Fraction (GF) vary with respect to discrete return airborne equivalents due to their greater sensitivity to reflectance differences between canopy and ground surfaces resulting from differences in footprint size, energy thresholding, noise characteristics and sampling geometry. Applying scaling factors to either the ground or canopy portions of waveforms has successfully circumvented this issue, but not at large scales. This study develops a method to scale spaceborne altimeter waveforms by identifying which remotely-sensed vegetation, terrain and environmental attributes are best suited to predicting scaling factors based on an independent measure of importance. The most important attributes were identified as: soil phosphorus and nitrogen contents, vegetation height, MODIS vegetation continuous fields product and terrain slope. Unscaled and scaled estimates of GF are compared to corresponding ALS data for all available data and an optimized subset, where the latter produced most encouraging results (R2 = 0.89, RMSE = 0.10). This methodology shows potential for successfully refining estimates of GF at large scales and identifies the most suitable attributes for deriving appropriate scaling factors. Large-scale active sensor estimates of GF can establish a baseline from which future monitoring investigations can be initiated via upcoming Earth Observation missions.