Sites In Ontario Research Articles

Intraspecific trait variation as a mechanism of coexistence of congeneric blueberry (Vaccinium) species after forest harvesting

Understorey shrubs of boreal forests grow vigorously after canopy removing disturbance such as clearcutting and fire and dominate the post-disturbance community. Many of these dominant shrubs are morphologically and phylogenetically closely related. How do they coexist despite having similar traits and resource needs? One way the coexisting plants may avoid competition is by niche differentiation that may alleviate the negative effects of competition due to high niche overlap. We studied two blueberry species, Vaccinium angustifolium and V. myrtilloides often found in proximity to one another after forest harvesting to test the hypothesis that coexisting congeneric species differentiate their resource acquisition and use through variation in their functional traits (niche differentiation). Discovering the coexistence mechanisms of Vaccinium spp. that flourish after forest harvesting and fire is important from both theoretical and applied perspectives. Vaccinium spp. are dominant shrubs after forest harvesting and fire and constitute a significant food source for wildlife and health-conscious consumers and are also of cultural significance to indigenous peoples. From three post-harvest forest sites in northwestern Ontario, we measured cover of Vaccinium spp. in 81 1 × 1 m quadrats where they occurred alone and together. We then excavated 103 ramets of the two Vaccinium spp. occurring alone and together after measuring three habitat variables (organic matter depth, soil moisture and soil temperature) in the immediate surroundings of the excavated plants. We measured five functional traits: height, canopy diameter, specific leaf area, specific stem density and specific root length. Using these data, we calculated functional hypervolumes (niche space occupancy) of each species occurring alone and together. We also calculated probabilistic niche overlap between the two species as well as their reaction norms to habitat variables. We found that species hypervolumes changed in size, and the probability and degree of overlap between the two Vaccinium spp. changed when occurring alone and co-occurring. Linear regression showed no significant effect of habitat factors on traits. We detected high intraspecific variation in some traits leading to shifts in hypervolumes when they co-occurred. We conclude that at fine spatial scales (homogeneous habitats, open canopy condition) individual trait variation allows for niche complementarity promoting coexistence among these important, early succession, closely related species.

Characteristics and Treatment Patterns of Patients with Diabetic Macular Edema Non-Responsive to Anti-Vascular Endothelial Growth Factor Treatment in Ontario, Canada.

To understand the demographics, clinical characteristics, treatment patterns, visual and anatomic responses of patients with diabetic macular edema (DME) initially treated with anti-vascular endothelial growth factor (anti-VEGF) agents in the real-world clinical setting. This retrospective cohort study used electronic health records to identify consecutively presenting patients with DME who received their first documented anti-VEGF injection (index injection) on or after 1 October 2015 and before 30 September 2016 (index period) at 4 clinical sites in Ontario, Canada. Patients receiving anti-VEGF injections in the study eye were followed for ≥18 months. After the first 3 monthly injections, patients were classified as "responder" (≥20% reduction in central retinal thickness [CRT] from index date) or "nonresponder" (<20% reduction in CRT) to anti-VEGF treatment. At 12 months, change from baseline (CFB) in best visual acuity (BVA) of responders (n = 30) was mean (SD) 12.8 (13.00) letters; CFB in nonresponders (n = 56) was 3.2 (16.3) letters. Sensitivity analyses stratified by initial BVA were supportive. Mean (SD) change in CRT (μm) was -160.4 (111.4) in responders and -62.2 (98.6) in nonresponders. While changes in anti-VEGF therapy were lower in responders versus nonresponders (10.0% vs 23.2%), mean number of injections was similar (8.3 in each cohort). Despite receiving a substantial number of injections and requiring changes in therapy more frequently, nonresponders showed a lack of clinically meaningful change in BVA and CRT. Nonresponders could be identified after 3 anti-VEGF injections. There remains an unmet need for treatment options in patients with DME who show a nonresponse after 3 months of anti-VEGF treatment.

A descriptive study of weaned piglet transport practices in Alberta, Ontario, and Saskatchewan, Canada between 2014 and 2018.

Canadian transport practices for shipments of newly weaned piglets are not well-described despite documentation requirements for those conducting the movement of these animals. The objective of this study was to describe the characteristics of weaned piglet transport events that occurred between 2014 and 2018 using records provided by five Canadian swine companies. Following cleaning and validation, the dataset included records from 6203 transport events involving the transport of approximately 6.9 million piglets (5.7kg, 4.1-7.9kg) from 62 origin sites in Alberta, Ontario, or Saskatchewan, Canada. This represents approximately 4.7% of the piglets estimated to have been weaned in Canada between 2014 and 2018, and 1.7% of sow farms in Canada according to 2016 National census data. Most transport events ended at farms in Canada (71.3%), while the remaining delivered piglets to one of eight American states. The predominant trailer types used were Straightdeck (51.4%) and Potbelly (36.6%), but this did not reflect the number of piglets transported as Potbelly trailers have greater load capacity. Transport events most frequently involved loading piglets from one origin barn and delivering them to a single destination barn (78.1%). Only transport events involving export to the United States picked up piglets from, or delivered them to, more than one farm site. Most transport events had very short trip distances (median distance: 48.0km; IQR: 497.0), but a marked range was observed (1.8-2931.2km). Average daily temperature data matched to the transport records by origin and destination location demonstrated ambient environmental conditions during these transport events ranged from -30.3-28.7°C. Overall, less than 10% of transport events had mortality occur. Comparable with other observational studies documenting weaned piglet mortality, the average in-transit mortality rate observed over the multiple seasons, companies, trip distances, and other characteristics in this dataset was 0.027%. However, instances of mortality over 1% did sporadically occur and could translate to considerable losses given the large load sizes common for piglets of this age and size (median load size: 1105 piglets; IQR: 1036 piglets). These data provide a better understanding of the interconnectedness of the Canadian swine industry as well as common transport practices which may inform future research on disease transmission in swine transport networks, or piglet welfare during transport. Additionally, variables that were not present in this dataset that would further strengthen these types of investigations are highlighted (e.g., space allowance).

Stopping study in chronic myeloid leukemia: Defining a new paradigm for Ontario CML1.

e19069 Background: The National Comprehensive Cancer Network (NCCN) guidelines state that in order to safely stop tyrosine kinase inhibitor (TKI) therapy in chronic myeloid leukemia (CML) patients, we need access to reliable polymerase chain reaction (PCR) tests on a monthly basis (4 weeks). However, Ontario, Canada can only provide a 6-week turnaround reliably. Therefore, we aimed to test a new paradigm for safely stopping TKI treatment by monitoring molecular response every 6 weeks for 6 months instead of the recommended 4-week intervals. Methods: A prospective pilot cohort study was conducted to assess the outcome of cessation of TKI treatment in chronic-phase CML patients. Eligibility criteria includes obtaining MMR4 (4-log reduction) for 2 years and had to have been on TKI therapy for 5 years. Patients' PCR for BCR-ABL, a driver of CML, was tested every 6 weeks for 30 weeks to ensure ongoing major molecular response (MMR). The primary endpoint was successful maintenance of MMR3 (3-log reduction) or greater at 36 weeks. Secondary endpoints include incidence of withdrawal syndrome, psychological effects, and quality of life (QoL) as per the EORTC Global Quality of Life scoring system were assessed during each visit every 6 weeks for 30 weeks. The secondary endpoint was assessing whether MMR was regained once lost. Results: 18 consenting patients were enrolled, 2 were censored from data analysis as additional time is required to assess whether they regained deep molecular response after stopping, 1 patient was deemed too early to analyze. 12 of the 17 enrolled participants were able to successfully stop TKI therapy and remain in remission at 30 weeks, yielding a 71% success rate. 5 patients had relapsed and 3 successfully regained MR 3.0 with resumption of TKI therapy. Conclusions: The findings demonstrated in a small pilot study that testing at 6-week intervals is safe and effective. Most Ontario CML patients treated in large community centers and have not stopped TKI therapy based on the NCNN guidelines that recommend a 4-week testing turnaround. We plan to expand this study to other sites in Ontario and if successful, this new paradigm may enable more CML patients to stop TKI therapy in a safe manner leading to significant financial and clinical impact. Data will be updated at the time of the conference. By determining that Q6 weekly is a safe paradigm, there is potential for increased comfort in patients unable to maintain Q4 weekly testing for various reasons such as compliance or patients in rural settings. Clinical trial information: OCT1250 , CML1 .

Effect of Free Medicine Distribution on Health Care Costs in Canada Over 3 Years

Few interventions are proven to reduce total health care costs, and addressing cost-related nonadherence has the potential to do so. To determine the effect of eliminating out-of-pocket medication fees on total health care costs. This secondary analysis of a multicenter randomized clinical trial using a prespecified outcome took place across 9 primary care sites in Ontario, Canada (6 in Toronto and 3 in rural areas), where health care services are generally publicly funded. Adult patients (≥18 years old) reporting cost-related nonadherence to medicines in the past 12 months were recruited between June 1, 2016, and April 28, 2017, and followed up until April 28, 2020. Data analysis was completed in 2021. Access to a comprehensive list of 128 medicines commonly prescribed in ambulatory care with no out-of-pocket costs for 3 years vs usual medicine access. Total publicly funded health care costs over 3 years, including costs of hospitalizations. Health care costs were determined using administrative data from Ontario's single-payer health care system, and all costs are reported in Canadian dollars with adjustments for inflation. A total of 747 participants from 9 primary care sites were included in the analysis (mean [SD] age, 51 [14] years; 421 [56.4%] female). Free medicine distribution was associated with a lower median total health care spending over 3 years of $1641 (95% CI, $454-$2792; P = .006). Mean total spending was $4465 (95% CI, -$944 to $9874) lower over the 3-year period. In this secondary analysis of a randomized clinical trial, eliminating out-of-pocket medication expenses for patients with cost-related nonadherence in primary care was associated with lower health care spending over 3 years. These findings suggest that eliminating out-of-pocket medication costs for patients could reduce overall costs of health care. ClinicalTrials.gov Identifier: NCT02744963.

Evaluating the use of Ca/Sr and 87Sr/86Sr ratios to track Ca sources in sugar maple in Ontario

Decades of acidic deposition and timber harvesting have depleted calcium (Ca) stocks in soils, especially at base-poor soils characterized by low base cation weathering rates. One approach to tracking Ca sources from soil is by using Ca/Sr ratios in vegetation, while 87Sr/86Sr ratios have also been used to estimate mineral weathering rates. To evaluate the uses of Ca/Sr ratios and Sr isotopes in identifying Ca sources in sugar maple ( Acer saccharum Marsh.) trees, three base-poor sites on the Canadian Shield and three limestone sites in southern Ontario were sampled for Ca, Sr, and 87Sr/86Sr ratios. Higher Ca/Sr ratios in soil extracts and sugar maple tissues at base-rich sites compared with base-poor sites reflect different minerology among regions, while the Ca/Sr discrimination factor between roots and foliage indicated that internal cycling exerts a major control on Ca/Sr ratios in sugar maple. At the three off-shield sites, 87Sr/86Sr ratios in soil and tree tissues were higher than precipitation but were indistinguishable for off-shield sites. Mixing models using a 1.0 mol L−1 HCl soil extract as the weathering endmember indicated that a lower proportion of weathering Ca compared with other geochemical approaches. One potential explanation is that the extraction method dissolves more recalcitrant minerals to a greater extent than under field conditions, leading to a higher weathering rate endmember value used in the mixing model.

Human and dog Bayesian dietary mixing models using bone collagen stable isotope ratios from ancestral Iroquoian sites in southern Ontario

Under the archaeological canine surrogacy approach (CSA) it is assumed that because dogs were reliant on humans for food, they had similar diets to the people with whom they lived. As a result, the stable isotope ratios of their tissues (bone collagen and apatite, tooth enamel and dentine collagen) will be close to those of the humans with whom they cohabited. Therefore, in the absence of human tissue, dog tissue isotopes can be used to help reconstruct past human diets. Here δ13C and δ15N ratios on previously published dog and human bone collagen from fourteenth-seventeenth century AD ancestral Iroquoian village archaeological sites and ossuaries in southern Ontario are used with MixSIAR, a Bayesian dietary mixing model, to determine if the dog stable isotope ratios are good proxies for human isotope ratios in dietary modeling for this context. The modeling results indicate that human dietary protein came primarily from maize and high trophic level fish and dogs from maize, terrestrial animals, low trophic level fish, and human feces. While isotopes from dog tissues can be used as general analogs for human tissue isotopes under CSA, greater insights into dog diets can be achieved with Bayesian dietary mixing models.

Modeling of dual-permeability gas and solute reactive transport in macroporous agricultural soils with a focus on GHG cycling and emissions

Agricultural soil is the domain where biogeochemical C-N turnover is affected by atmospheric and hydrologic processes, playing a vital role in anthropogenic greenhouse gas (GHG) emissions and thus affecting global climate change. GHG cycling and emissions are further complicated by the characteristics of soil structure, in particular macropores (i.e., preferential flow pathway). In this study, the processes of non-equilibrium gas diffusion and gas exchange were implemented into an existing dual-permeability flow and reactive solute transport model. The model was then used in a sensitivity analysis to evaluate the suitability of the modeling approach to account for development of anaerobic hotspots, with an emphasis on assessing N2O production and emissions. The sensitivity analysis combined with characteristic time scale analysis suggests that the development of anaerobic hotspots is controlled by a combination of both physical and geochemical parameters. Time scale analysis of O2 supply and consumption indicates that the occurrence of anaerobic hotspots is determined by the balance between characteristic times of O2 diffusion through the soil profile or exchange between macropores and the soil matrix, and the characteristic time of O2 consumption. Motivated by these findings, the present model was applied to simulate GHG cycling at a field site in Ontario, Canada, featuring macroporous agricultural soil. The model generally reproduced observed spatiotemporal variations in pore gas O2 and GHG concentrations and fluxes. Simulation results suggest that at this site, gas exchange processes between regions of preferential flow and the soil matrix play an important role in controlling the spatial variation of O2 in the soil. The simulations illustrate how the release of GHGs from the soil matrix into the macropores can lead to GHG emissions to the atmosphere. The modeling approach presented here, including dual domain flow and solute transport, as well as dual domain gas transport, shows promise for future studies with the aim to develop a more complete understanding of how soil structure affects complex GHG cycling in agricultural soils.

Effects of freeze-thaw cycles on methanogenic hydrocarbon degradation: Experiment and modeling

Cold regions are warming much faster than the global average, resulting in more frequent and intense freeze-thaw cycles (FTCs) in soils. In hydrocarbon-contaminated soils, FTCs modify the biogeochemical and physical processes controlling petroleum hydrocarbon (PHC) biodegradation and the associated generation of methane (CH4) and carbon dioxide (CO2). Thus, understanding the effects of FTCs on the biodegradation of PHCs is critical for environmental risk assessment and the design of remediation strategies for contaminated soils in cold regions. In this study, we developed a diffusion-reaction model that accounts for the effects of FTCs on toluene biodegradation, including methanogenic biodegradation. The model is verified against data generated in a 215 day-long batch experiment with soil collected from a PHC contaminated site in Ontario, Canada. The fully saturated soil incubations with six different treatments were exposed to successive 4-week FTCs, with temperatures oscillating between −10 °C and +15 °C, under anoxic conditions to stimulate methanogenic biodegradation. We measured the headspace concentrations and 13C isotope compositions of CH4 and CO2 and analyzed the porewater for pH, acetate, dissolved organic and inorganic carbon, and toluene. The numerical model represents solute diffusion, volatilization, sorption, as well as a reaction network of 13 biogeochemical processes. The model successfully simulates the soil porewater and headspace concentration time series data by representing the temperature dependencies of microbial reaction and gas diffusion rates during FTCs. According to the model results, the observed increases in the headspace concentrations of CH4 and CO2 by 87% and 136%, respectively, following toluene addition are explained by toluene fermentation and subsequent methanogenesis reactions. The experiment and the numerical simulation show that methanogenic degradation is the primary toluene attenuation mechanism under the electron acceptor-limited conditions experienced by the soil samples, representing 74% of the attenuation, with sorption contributing to 11%, and evaporation contributing to 15%. Also, the model-predicted contribution of acetate-based methanogenesis to total produced CH4 agrees with that derived from the 13C isotope data. The freezing-induced soil matrix organic carbon release is considered as an important process causing DOC increase following each freezing period according to the calculations of carbon balance and SUVA index. The simulation results of a no FTC scenario indicate that, in the absence of FTCs, CO2 and CH4 generation would decrease by 29% and 26%, respectively, and that toluene would be biodegraded 23% faster than in the FTC scenario. Because our modeling approach represents the dominant processes controlling PHC biodegradation and the associated CH4 and CO2 fluxes, it can be used to analyze the sensitivity of these processes to FTC frequency and duration driven by temperature fluctuations.

Conditions and strategies influencing sustainability of a community-based exercise program incorporating a healthcare-community partnership for people with balance and mobility limitations in Canada: A collective case study of the Together in Movement and Exercise (TIME™) program.

Community-based exercise programs delivered through healthcare-community partnerships (CBEP-HCPs) are beneficial to individuals with balance and mobility limitations. For the community to benefit, however, these programs must be sustained over time. To identify conditions influencing the sustainability of CBEP-HCPs for people with balance and mobility limitations and strategies used to promote sustainability based on experiences of program providers, exercise participants, and caregivers. Using a qualitative collective case study design, we invited stakeholders (program providers, exercise participants, and caregivers) from sites that had been running a CBEP-HCP for people with balance and mobility limitations for ≥4 years; and sites where the CBEP-HCP had been discontinued, to participate. We used two sustainability models to inform development of interview guides and data analysis. Qualitative data from each site were integrated using a narrative approach to foster deeper understanding of within-organization experiences. Twenty-nine individuals from 4 sustained and 4 discontinued sites in Ontario (n = 6) and British Columbia (n = 2), Canada, participated. Sites with sustained programs were characterized by conditions such as need for the program in the community, presence of secure funding or cost recovery mechanisms, presence of community partners, availability of experienced and motivated instructors, and the capacity to allocate resources towards program marketing and participant recruitment. For sites where programs discontinued, diminished participation and/or enrollment and an inability to allocate sufficient financial, human, and logistical resources towards the program affected program continuity. Participants from discontinued sites also identified issues such as staff with low motivation and limited experience, and presence of competing programs within the organization or the community. Staff associated the absence of referral pathways, insufficient community awareness of the program, and the inability to recover program cost due to poor participation, with program discontinuation. Sustainability of CBEP-HCPs for people with balance and mobility limitations is influenced by conditions that exist during program implementation and delivery, including the need for the program in the community, and organization and community capacity to bear the program's financial and resource requirements. Complex interactions among these factors, in addition to strategies employed by program staff to promote sustainability, influence program sustainability.

Effect of Polymer-Coated Urea/Urea Blends on Corn Yields under Short Growing Season Conditions in Eastern Canada

Polymer-coated urea (PCU) was developed to better synchronize nitrogen (N) supply with crop needs and reduce N losses. The objective of this work was to evaluate the effects of different N rates prepared using combinations of urea and ESN (PCU) on corn (Zea mays L.), grain yield, yield components, in-season nutritional status, and residual soil N. Field experiments were conducted on two sites in eastern Ontario (Canada); Kemptville (sandy loam) and Winchester (clay-loam), and repeated over three years (2011–2013). A total of ten treatments were applied using combinations of three N rates (50, 100, and 150 kg N ha−1) and three fertilizer proportions (100% urea, 75:25 urea:ESN, and 60:40 urea:ESN) for each rate. The tenth treatment consisted of a non-fertilized control (0 N). Grain yield was significantly affected by N source, N rate, site, and year. There was no significant effect of the N source in most sites/years. In the wetter season 2013, treatment 100N60:40 in the sandy site produced a similar yield to treatments receiving 150 kg N ha−1. In the clay-loam site, the 150N75:25 treatment had a yield advantage of 11–12% compared with straight urea. Chlorophyll index generally increased with the higher N application rate. The other grain parameters were little affected by the N rate or source. Soil residual mineral N tended to increase with ESN blends at 100 and 150 kg N ha−1 compared with straight urea. Our findings indicate that replacing a portion of urea with PCU might save N in lighter soils prone to leaching especially in wet years without affecting yields.

Continuous Measurements and Source Apportionment of Ambient PM2.5-Bound Elements in Windsor, Canada

Ambient fine particulate matter (PM2.5) levels in Windsor, Ontario, Canada, are impacted by local emissions and regional/transboundary transport input and also attributable to secondary formation. PM2.5-bound elements were monitored hourly in Windsor from April to October 2021. Observed concentrations of the elements were generally comparable to historical measurements at urban sites in Ontario. A clear diurnal pattern was observed for most of the elements, i.e., high in the morning and low in the afternoon, mostly related to evolution of atmospheric mixing heights and local anthropogenic activities. Conversely, sulfur showed elevated levels in the afternoon, suggesting conversion of gaseous sulfur dioxide to particulate sulphate was enhanced by increased ambient temperatures. Five source factors were resolved using the US EPA positive matrix factorization model, including three traffic-related sources (i.e., vehicular exhaust, crustal dust, and vehicle tire and brake wear factors) and two industrial sources (i.e., coal/heavy oil burning and metal processing factors). Overall, the three traffic-related sources were mostly local and contributed to 47% of the total elemental concentrations, while the two industrial sources may originate from regional/transboundary sources and contributed to 53%. Measures to control both local traffic emissions and regional/transboundary industrial sources would help reduce levels of PM2.5-bound elements in Windsor.

Reconstructing the Procession of Nerthus

Primary data gathering for this work included participant observation research at the procession of Nerthus at Well and Tree Gathering in May of 2018 and 2019 at Raven’s Knoll, a privately-owned campground and dedicated Pagan festival site in eastern Ontario. It draws upon a larger research project on inclusive Canadian Heathen ritual practices and environmental values. Well and Tree Gathering includes Pagans of various types, but is largely run by Heathens, and prominently features the Heathen deity Nerthus. Practitioners conduct a reconstructionist revival of the procession of Nerthus based on Tacitus’ description of such events in Germania, which included human sacrifice. Contemporary Heathens revere Nerthus as a primordial power, process her veiled figure through the campground, and give her offerings in a sacred body of water. Giving these offerings operationalizes the values of inclusion and sharing, and contributes to the formation of ecological conscience through relational ontology.

Lost reproductive value reveals a high burden of juvenile road mortality in a long-lived species.

Adult mortality is often the most sensitive vital rate affecting at-risk wildlife populations. Therefore, road ecology studies often focus on adult mortality despite the possibility for roads to be hazardous to juvenile individuals during natal dispersal. Failure to quantify concurrent variation in mortality risk and population sensitivity across demographic states can mislead the efforts to understand and mitigate the effects of population threats. To compare relative population impacts from road mortality among demographic classes, we weighted mortality observations by applying reproductive value analysis to quantify expected stage-specific contributions to population growth. We demonstrate this approach for snapping turtles (Chelydra serpentina) observed on roads at two focal sites in Ontario, Canada, where we collected data for both live and dead individuals observed on roads. We estimated reproductive values using stage-classified matrix models to compare relative population-level impacts of adult and juvenile mortality. Reproductive value analysis is a tractable approach to assessing demographically variable effects for applications covering large spatial scales, nondiscrete populations, or where abundance data are lacking. For one site with long-term life-history data, we compared demographic frequency on roads to expected general population frequencies predicted by the matrix model. Our application of reproductive value is sex specific but, as juvenile snapping turtles lack external secondary sex characters, we estimated the sex ratio of road-crossing juveniles after dissecting and sexing carcasses collected on roads at five sites across central Ontario, Canada. Juveniles were more abundant on roads than expected, suggesting a substantial dispersal contribution, and the road-killed juvenile sex ratio approached 1:1. A higher proportion of juveniles were also found dead compared with adults, and cumulative juvenile mortality had similar population-level importance as adult mortality. This suggests that the impact of roads needs to be considered across all life stages, even in wildlife species with slow life histories, such as snapping turtles, that are particularly sensitive to adult mortality.

The influence of environmental and ecological factors on the accumulation and distribution of short- and long-chain perfluoroalkyl acids in a mid-trophic avian insectivore

Perfluoroalkyl acids (PFAAs) include perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonic acid (PFHxS), and perfluorodecane sulfonic acid (PFDS), as well as increasingly used alternative short-chain perfluorosulfonic acids (PFSAs) and short- and long-chain (≥C9) perfluorocarboxylic acids (PFCAs). In the present study, tissues of tree swallows (Tachycineta bicolor) from two sites in southern Ontario, Canada, were analyzed for 17 individual PFAAs and showed egg and nestling tissue (liver, carcass) profiles dominated by PFOS (57–66%). The remaining PFAAs contributed ≤7% each, although collectively the long-chain PFCAs comprised 21–29% of the PFAAs. The short-chain PFSAs and PFCAs were among the lowest concentrations, suggesting that despite increased production and use of these alternative PFAAs, they are not accumulated to the same extent as the long-chain PFSAs and PFCAs. PFOS, PFDS, and some long-chain PFCAs were significantly higher in eggs than in livers and carcasses, whereas PFOA and the two short-chain PFCAs were significantly higher in nestling tissues than in eggs. For the two short-chain PFSAs, concentrations were similar among tissues. Tree swallow tissues at the site near a wastewater treatment plant (WWTP) outfall showed higher concentrations of PFOS, PFDS, PFHxS, and some long-chain PFCAs than tree swallows sampled at the nearby reference site; however, the influence of the WWTP was more equivocal for PFOA, other long-chain PFCAs, and short-chain PFSAs and PFCAs. Carbon stable isotopes (δ13C) and fatty acid signatures indicated that the diets of the WWTP swallows were more terrestrial than the reference swallows. Nonetheless, models considering environmental and ecological variables indicated that site was often the primary driver of PFAA variation among the swallows, with less or no influence of dietary patterns, or sex or body condition, revealing that of WWTP effluent can be an important environmental source of the major PFAAs in tree swallows.

New opportunities for low-cost LiDAR-derived snow depth estimates from a consumer drone-mounted smartphone

Snow has significant impacts on springtime flooding, water resource management practices and the regional water-energy budget. In situ observations are considered some of the highest quality measurements of snow depth available, and are useful constraints for numerical weather prediction models and reanalysis system estimates of snow water equivalent. The application of laser altimetry (LiDAR-Light Detection and Ranging) for measuring snow depth has proven an effective method for quickly observing large areas, however this technique is expensive to perform due to the high cost of the necessary equipment coupled with required operator training. In this work, we examine the capabilities of the iPhone 12 Pro LiDAR (iLiDAR) when attached to a consumer-grade DJI Phantom 4 quadcopter in estimating snow depth at three study sites in southern Ontario, Canada. Initial comparisons between drone iLiDAR depth estimates and collocated snow ruler measurements demonstrate good agreement, with a root-mean-square error of 3 cm and absolute mean error of 2.5 cm. The intersection of these two technologies defines a novel, low-cost alternative to traditional LiDAR-based snow depth measurement systems, while maintaining a high level of observational accuracy and precision.

Baseline Inappropriate Antibiotic Use in Primary Care Patients with Viral Respiratory Tract Infections with 2019 and 2020.

Context: Respiratory tract infection (RTI) is the leading cause of avoidable antimicrobial use in primary care. How the COVID-19 pandemic has impacted antibiotic prescribing practices across Canada is unknown. The purpose of this study was to examine rates of antibiotic prescribing for RTI in primary care during the first year of the pandemic (2020), compared to baseline in 2019. Study Design and Analysis: Cross sectional study. Dataset: Canadian Primary Care Sentinel Surveillance Network electronic medical record data from sites in British Columbia, Alberta, Manitoba, Ontario, Quebec, Nova Scotia and Newfoundland. Population Studied: Patients that met the case definition criteria for an RTI or a Urinary Tract Infection (UTI) in 2019, and in 2020. Outcome measures: We examined oral antibiotic prescribing for patients who were identified as having a primary care visit for RTI. The same analysis was repeated for urinary tract infection (UTI) as a tracer condition. The antibiotic use considered avoidable for RTI was defined by Choosing Wisely Canada. Results: A total of 1,692,876 patients with a valid birth year and sex and at least one visit to primary care in 2019 and 2020 were included. Patient visits for RTI decreased from 2.3% in 2019 to 1.6% in 2020 (p<.0001), as did patient visits for UTI (1.1% vs 0.7%, p<.0001). In 2019, 28.0% of patients visits for RTI were prescribed an antibiotic, and this proportion decreased significantly to 20.6% in 2020 (<.0001). The drop in antibiotic prescriptions for RTI was driven by a decrease in prescribing for common cold (13.6% vs. 11.3%, <.0001) and for acute bronchitis/asthma (15.2% vs. 7.3%, p<.0001). In comparison, antibiotic prescribing for visits related to UTI increased marginally between 2019 and 2020 (71.6% vs. 72.3%, p=0.007). Conclusions: A significant decrease in antibiotic prescribing for RTI across primary care was observed during the first year of the COVID-19 pandemic, likely related to the changes in epidemiology and care delivery models in primary care. CPCSSN can provide pan-Canadian surveillance of antibiotic prescribing practices in primary care that can be used for provider feedback and quality improvement.

Demographic characteristics, outcomes and experience of patients using virtual urgent care services from 14 emergency department led sites in Ontario.

As part of the COVID-19 pandemic response, the Ontario Ministry of Health funded a virtual care pilot program intended to support emergency department (ED) diversion of patients with low acuity complaints and reduce the need for face-to-face contact. The objective was to describe the demographic characteristics, outcomes and experience of patients using the provincial pilot program. This was a prospective cohort study of patients using virtual care services provided by 14 ED-led pilot sites from December 2020 to September 2021. Patients who completed a virtual visit were invited by email to complete a standardized, 25-item online survey, which included questions related to satisfaction and patient-reported outcome measures. There were 22,278 virtual visits. When patients were asked why they contacted virtual urgent care, of the 82.7% patients who had a primary care provider, 31.0% said they could not make a timely appointment with their family physician. Rash, fever, abdominal pain, and COVID-19 vaccine queries represented 30% of the presenting complaints. Of 19,613 patients with a known disposition, 12,910 (65.8%) were discharged home and 3,179 (16.2%) were referred to the ED. Of the 2,177 survey responses, 94% rated their overall experience as 8/10 or greater. More than 80% said they had answers to all the questions they had related to their health concern, believed they were able to manage the issue, had a plan they could follow, and knew what to do if the issue got worse or came back. Many presenting complaints were low acuity, and most patients had a primary care provider, but timely access was not available. Future work should focus on health equity to ensure virtual care is accessible to underserved populations. We question if virtual urgent carecan be safely and more economically provided by non-emergency physicians.

Predicting aboveground biomass carbon sequestration potential in hybrid poplar clones under afforestation plantation management in southern Ontario, Canada

Afforestation systems as a pathway for natural climate solutions contributing to terrestrial C sequestration are influenced by agroclimatic conditions, tree species and clones. This study validated a regression equation to predict aboveground biomass C (AGBC) sequestration potentials of hybrid poplar clones under afforestation plantation and compared these clones’ adaptability to three levels of land suitability in four afforestation sites in southern Ontario, Canada. Results validated the proven ability of the GenOnBio model to reasonably predict AGBC content in all tested clones. This research suggests that DN154 and FFC1 having C sequestration rates of 2.19 and 2.13 Mg C ha-1 y-1, respectively, are suitable for marginal lands having high land suitability condition. In contrast, DTAC29, and DTAC26 (0.56 and 0.88 Mg C ha-1 y-1, respectively) should not be selected for the above land suitability. On marginal lands with severe limitations, NM6 (1.53 Mg C ha-1 y-1) showed the highest adaptability for AGBC sequestration. Our findings confirm that poplar afforestation on marginal lands in southern Ontario, at least up to the age of 15 years, can significantly contribute to AGBC sequestration, which in turn can have significant positive influence on the current 2 billion tree planting program initiated by the federal government.

Considering passenger pigeon abundance and distribution in the Late Woodland zooarchaeological record of southern Ontario, Canada

AbstractThe passenger pigeon (Ectopistes migratorius) was once the most abundant bird species in North America. Flocks of these birds witnessed in the early 19th century were so vast that they were said to darken the sky for days as they passed. Early syntheses of passenger pigeon remains in archaeological contexts in the eastern United States, in contrast, found them to be relatively rare in relation to other fowl, leading to the suggestion that the colonial‐era hyper‐abundance of passenger pigeons was a post‐European‐contact phenomenon resulting from contact‐induced demographic and ecological changes. In this paper, we provide new insights into passenger pigeon historical ecology through a synthesis and GIS‐based analysis of zooarchaeological data on skeletal remains from 157 Late Woodland (ca. 900–1650 CE) sites in Ontario, Canada. Our results reveal that passenger pigeon bones are common, and often abundant, in Late Woodland archaeological assemblages in Ontario, which speaks to the species' importance to Indigenous peoples in the region. However, the relative abundance of passenger pigeon remains varies over time, suggesting longer‐term trends in their availability and/or in hunting patterns.