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Infections with antimicrobial resistant pathogens are a major threat to human and animal health worldwide. Further, reduction of livestock-associated antimicrobial use (AMU) is often identified as an area of focus. Selective dry cow therapy (DCT) warrants consideration as an important way to decrease AMU on Canadian dairy farms. In addition, teat sealants (TS) are a nonantimicrobial alternative for prevention of intramammary infection during the dry period. Therefore, objectives of this study were to determine how antimicrobials and TS are used at dry-off on Canadian dairy farms to determine selective DCT uptake and enacted selection protocols. It was expected that these data will provide a baseline understanding of DCT practices and highlight areas for future intervention to further reduce AMU. An observational study was conducted utilizing 2 in-person questionnaires conducted between July 2019 and September 2021 on 144 participating dairy farms in 5 Canadian provinces (British Columbia = 30, Alberta = 30, Ontario = 31, Québec = 29, and Nova Scotia = 24). Overall, 45 farms (31%) reported adopting selective DCT, 95 (66%) enacted blanket DCT, and 4 (3%) did not provide antimicrobial DCT. Farms enacting selective DCT had approximately 50% less intramammary antimicrobials used at dry-off compared with blanket DCT farms. Cow somatic cell count history was the most common criterion for selective DCT decision-making, followed by previous clinical mastitis history, bacteriological culture, and milk production. A slight majority of farms (56%) applied TS to all cows at dry-off, whereas 17 farms (12%) used TS selectively, and 46 farms (32%) did not use TS. Larger herds more often used TS, and farms with an automatic milking system more often used TS selectively than applied to all cows. Results highlighted the variability in antimicrobial treatment and TS use protocols at dry-off on Canadian dairy farms, and the potential for further antimicrobial reduction with increased adoption of selective DCT. [ABSTRACT FROM AUTHOR]

Unlike other high-income countries, Canada has no national policy for drugs treating rare diseases (orphan drugs). Nevertheless, in 2022, the Canadian government committed to creating a national strategy to make access to these drugs more consistent. Our aim was to study whether recommendations made by the Canadian Agency for Drugs and Technology in Health (CADTH) translated into coverage decisions for orphan drugs in Ontario, the largest Canadian province. This study is the first to look at this question for orphan drugs, which are at the center of policy attention. We included 155 orphan drug-indication pairs approved and marketed in Canada between October 2002 and April 2022. Cohen's kappa was used to test the agreement across health technology assessment (HTA) recommendations and coverage decisions in Ontario. Logistic regression was used to test which factors, relevant to decision-makers, might be associated with funding in Ontario. We found only fair agreement between CADTH's recommendations and coverage decisions in Ontario. Although a positive and statistically significant association between favorable HTA recommendations and coverage was found, more than half of the drugs with a negative HTA recommendation were available in Ontario, predominately through specialized funds. Successful pan-Canadian pricing negotiations were a strong predictor of coverage in Ontario. Despite efforts to harmonize access to drugs across Canada, considerable room for improvement remains. Introducing a national strategy for orphan drugs could help increase transparency, consistency, promote collaborations, and make access to orphan drugs a national priority. • Recommendations by the Canadian Agency for Drugs and Technology in Health do not always translate to provincial coverage decisions for new drugs. • We explored whether Canadian Agency for Drugs and Technology in Health's recommendations are aligned with coverage decisions for orphan drugs in Ontario. • Negative health technology assessment recommendations did not necessarily translate to no pan-Canadian pricing negotiations. • More than half the drugs with negative health technology assessment recommendations were available in Ontario through specialized funds. • A national strategy for orphan drugs could prioritize access to these treatments at a national level and harmonize access, at least to some extent, across Canada. [ABSTRACT FROM AUTHOR]

Deploying negative emission technologies has become crucial for limiting the global temperature rise to approximately 1.5 °C above preindustrial levels. DAC technologies are being explored as one of the prospective options. These technologies have been thoroughly investigated as a potential project to capture CO 2 emissions and provide purified air, natural gas, or fuel oil. An applied approach, on the other hand, was not taken into consideration while evaluating the influence that this technology has on emissions. For this reason, British Columbia provides a substantial chance to examine emissions that were produced after the DAC actions were put into place in 2015. In this study, the difference-in-differences methodology is employed for the very first time to compare the emissions that are produced by the transport sectors in British Columbia with those emitted by other provinces in Canada. The role that GDP and population play in the release of emissions is also taken into consideration in this paper. Based on the research results, it can be observed that the implementation of DAC initiatives has yielded notable effects. Evidence shows that the DAC effort has led to an average reduction of 0.08 in logarithmic CO 2 emissions in the transport sector. By accounting for GDP and population, the empirical results indicate that DAC technology reduced CO 2 emissions in British Columbia compared to provinces without DAC facilities. DAC initiatives are expected to become increasingly prevalent between the mid-2030s and 2040s. Overall policy implications suggest that there is a need for DAC technologies to collaborate with alternative mitigation technologies, or alternative technologies should collaborate with DAC technologies that are more efficient to achieve the targeted goals in a short time. • The study offers empirical evidence of DAC technology's impact, providing insights beyond theoretical conjectures. • Based on the research results, it can be seen that the implementation of DAC facilities has yielded notable effects. • DAC technology in British Columbia has led to a significant and negative impact on CO 2 emissions compared to other provinces without DAC facilities. • The study highlights the differential effectiveness of DAC across transport sectors, pointing toward a need for tailored implementation strategies. [ABSTRACT FROM AUTHOR]

Calf rearing practices differ among farms, including feeding and weaning methods. These differences may relate to how dairy producers view these practices and evaluate their own success. The aim of this study was to investigate perspectives of dairy producers on calf rearing, focusing on calf weaning and how they characterized weaning success. We interviewed dairy producers from 16 farms in Western Canada in the following provinces: British Columbia (n = 12), Manitoba (n = 2), and Alberta (n = 2). Participants were asked to describe their heifer calf weaning and rearing practices, and what they viewed as successes and challenges in weaning and rearing calves. Interviews were recorded, transcribed, and subjected to qualitative analysis from which we identified the following 4 major themes: (1) reliance on calf-based measures (e.g., health, growth, and behavior), (2) management factors and personal experiences (e.g., ease, consistency, and habit), (3) environmental factors (e.g., facilities and equipment), and (4) external support (e.g., advice and educational opportunities). These results provided insight into how dairy producers view calf weaning and rearing, and may help inform the design of future research and knowledge transfer projects aimed at improving management practices on dairy farms. [ABSTRACT FROM AUTHOR]

In Canada, greenhouse gas (GHG) emissions continue to remain high despite the federal government's commitment to reduce GHG emissions. Environmental policy across Canadian provinces has largely lacked consistency with some provinces implementing targeted policy such as carbon taxes while others have strongly resisted the federal government's attempts to encourage such policy. This study examines the impact of environmental policy on GHG gas emissions across Canadian provinces with policy uniquely measured by public and business sector spending on environmental protection as well as notable province-specific policies. An extended STIRPAT model is specified with the inclusion of proxies for environmental policy using panel data from Canada's ten provinces from 1995 to 2019. The cointegration and the error correction modelling approaches are employed to estimate the non-stationary panel data. A pooled mean group estimation is applied to provide short run and long run coefficients. The findings indicate that although per capita GDP is the main driver of GHG emissions in Canada, environmental policy has a significant mitigating effect, as shown by the negative association between emissions and private and public sector spending on environmental protection in the long run. Furthermore, provinces with targeted policies, such as Ontario's coal phase-out and British Columbia's carbon tax, experienced significant emissions reductions. The theoretical implication is the successful addition of policy variables to the STIRPAT model, providing the model a new application for future research. [Display omitted] • Assess the impact of environmental protection policies on per capita greenhouse gas emissions in Canada. • Utilize public and private expenditures on environmental protection, along with provincial policies. • Extend the STIRPAT model to incorporate environmental protection policies in an empirical model. • Demonstrate a significant negative relationship between environmental protection policies and GHG emissions. • Offer insights with implications for global environmental sustainability efforts. [ABSTRACT FROM AUTHOR]

Background: Frailty is a geriatric syndrome that leaves people vulnerable to adverse outcomes. In cardiac surgery, minimal data describe associations between frailty and patient-centred outcomes. Our objective was to estimate the association between frailty and days alive at home after cardiac surgery.Methods: We conducted a population-based cohort study using linked health administrative data in the Canadian province of Ontario. All individuals >65 yr at the time of cardiac surgery were assigned a frailty score using a validated frailty index. Days alive and at home in the 30 and 365 days after surgery were calculated. The unadjusted and adjusted associations between frailty and days alive at home were calculated.Results: We identified 61 389 patients from 2009 to 2015. Frailty was associated with reduced days at home within 30 days (adjusted ratio of means for every 10% increase in frailty=0.79; 95% confidence interval [CI], 0.78-0.81; P<0.0001) and 365 days (adjusted ratio of means for every 10% increase in frailty=0.92; 95% CI, 0.91-0.93; P<0.0001) of surgery. Results were consistent in sensitivity analyses (5.0 fewer days alive at home [95% CI, 4.8-5.2] within 30 days and 9.0 fewer days alive at home [95% CI, 8.7-9.2] within 365 days after surgery).Conclusion: Frailty is associated with a reduction in days alive at home after major cardiac surgery. This information should be considered in prognostic discussions before surgery and in care planning for vulnerable older patient groups. Days alive at home may be a useful outcome for routine measurement in quality, reporting, and studies using routinely collected data. [ABSTRACT FROM AUTHOR]

Feeding high-quality colostrum is essential for calf health and future productivity. Therefore, accurate assessment of colostrum quality is a key component of dairy farm management plans. Direct and indirect methods are available for assessment of colostrum quality; however, the indirect methods are rapid, inexpensive, and can be performed under field settings. A hierarchical latent class model fit within a Bayesian framework was used to estimate the sensitivity (Se) and specificity (Sp) of the radial immunodiffusion (RID) assay, transmission infrared (TIR) spectroscopy, and digital Brix refractometer for the assessment of low-quality bovine colostrum in Atlantic Canada dairy herds. The secondary objective of the study was to describe the distribution of herd prevalence of low-quality colostrum. Colostrum quality of 591 samples from 42 commercial Holstein dairy herds in 4 Atlantic Canada provinces was assessed using RID, TIR spectroscopy, and digital Brix refractometer. The accuracy of all tests at different Brix value thresholds was estimated using Bayesian latent class models to obtain posterior estimates [medians and 95% Bayesian credibility intervals (95% BCI)] for each parameter. Using a threshold of <23% for digital Brix refractometer and <50 g/L for RID and TIR spectroscopy, median (95% BCI) Se estimates were 73.2 (68.4–77.7), 86.2 (80.6–91.0), and 91.9% (89.0–94.2), respectively. Median (95% BCI) Sp estimates were 85.2% (81.0–88.9) for digital Brix refractometer, 99.4% (97.0–100) for RID, and 90.7% (87.8–93.2) for TIR spectroscopy. Median (95% BCI) within-herd low-quality colostrum prevalence was estimated at 32.5% (27.9–37.4). In conclusion, using digital Brix refractometer at a Brix threshold of <23% could reduce feeding of low-quality colostrum to calves and improve colostrum and calf management practices in Atlantic Canada dairy herds. The TIR spectroscopy showed high Se in detection of low-quality colostrum. However, the RID assay, which is used as the reference test in several studies, showed limited Se for detection of low-quality colostrum. [ABSTRACT FROM AUTHOR]

Through survey and focus groups in two provinces in Canada misunderstanding and confusion surrounding Low-Dose Ionizing Radiation (LDIR) is explored specifically surrounding medical procedures, risk, and benefits. Generally people associated the word radiation with harm, but when asked participants were not concerned about LDIR. Approximately equal numbers (40%) thought LDIR was 'difficult' as those that thought it was 'easy' but research results reveal confusion about the definition of and sources of LDIR. Most people believed the benefits of LDIR outweighed the risks. Further, many had inaccurate views of 'high' dose radiation. Scientists and the Canadian regulator were determined to be the most trusted sources of information while elected officials and industry representatives the least trusted. Participants wanted more information on whether LDIR was a problem in Canada, what the risks were associated with it, as well as the applicable protections, rules and regulations. Focus group participants expressed a preference for face-to-face exchange of information, but mass media remains an important source of information as the first-place people check for answers. Future research surrounding behavioural science and LDIR communications, and deep LDIR science communication will be important in addressing this issue. • People do not have high levels of knowledge of low dose ionizing radiation (LDIR). • Most people respond well to the term LDIR and believe benefits outweigh negatives. • Scientists are most trusted communicators followed by the regulator. • Some participants wanted more information surrounding radiation. [ABSTRACT FROM AUTHOR]

The present study empirically investigates whether targeted government spending and environmental policies promote green growth, as measured by greenhouse gas productivity. Government spending for pollution abatement (GEPA) represents non-market environmental policies encompassing both enforcement regulations and stakeholder incentives, while policy dummy represents province specific targeted environmental policies. Using panel data from 1995 to 2020 across ten provinces of Canada, an empirical model based on STIRPAT has been developed and estimated, addressing various econometric issues to ensure the robustness and consistency of the results. The findings confirm that both GEPA and targeted environmental policies are crucial determinants in achieving green growth. Additionally, variables such as business sector expenditures for R&D, the share of renewable energy, per capita GDP, and population also contribute to green growth. These results highlight the importance of the stick-and-carrot approach as a key strategy and policy tool for sustainable development. The implications of these findings extend beyond Canada and hold valuable lessons for emerging and developing countries that predominantly rely on command-and-control regulations without adequate support. To effectively address the challenge of achieving green growth, a coordinated approach that combines targeted government spending and environmental policies, supported by innovation and renewable energy exploration, is essential. Overall, this study's findings have significant implications for environmental sustainability on a global scale. [Display omitted] • Examines the effect of targeted government spending and environmental policies on green growth in Canada. • Uses greenhouse gas productivity as an index of green growth. • Estimates the empirical model developed addressing advanced econometric issues related to panel data for 1995–2020. • Controls renewable energy, innovation, per capita income, population. • Have significant implications for environmental sustainability on a global scale. [ABSTRACT FROM AUTHOR]

The United States Food & Drug Administration released an advisory in 2016 that fluoroquinolones be relegated to second-line agents for uncomplicated urinary tract infections (UTIs) given reports of rare but serious side effects; similar warnings have followed from Health Canada and the European Medicines Agency. The objective was to determine whether alternative non-fluoroquinolone agents are as effective as fluoroquinolones in the treatment of UTIs. We conducted a retrospective population-based cohort study using administrative health data from six Canadian provinces. We identified women (n = 1 585 997) receiving antibiotic treatment for episodes of uncomplicated UTIs (n = 2 857 243) between January 1 2005 and December 31 2015. Clinical outcomes within 30 days from the initial antibiotic dispensation were compared among patients treated with a fluoroquinolone versus non-fluoroquinolone agents. High-dimensional propensity score adjustments were used to ensure comparable treatment groups and to minimize residual confounding. Fluoroquinolone use for UTI declined over the study period in five of six Canadian provinces and accounted for 22.3–48.5% of treatments overall. The pooled effect across the provinces indicated that fluoroquinolones were associated with fewer return outpatient visits (OR 0.89, 95%CI 0.87–0.92), emergency department visits (OR 0.74, 95%CI 0.61–0.89), hospitalizations (OR 0.83, 95%CI 0.77–0.88), and repeat antibiotic dispensations (OR 0.77, 95%CI 0.75–0.80) within 30 days. Fluoroquinolones are associated with improved clinical outcomes among women with uncomplicated UTIs. This benefit must be weighed against the risk of fluoroquinolone resistance and rare but serious fluoroquinolone side effects when selecting first-line treatment for these patients. [ABSTRACT FROM AUTHOR]

• A novel bridge weigh-in-motion method is presented using parametric dynamic bridge-vehicle interaction formulation. • Modal parameters extracted from ambient vibration tests are used to accurately simulate the bridge structures. • The formulation offers superior computational efficiency since it eliminates the need for calibrated finite element models. • The proposed method resulted in accurate estimations even when the vehicle travel path differs from calibrations. • The Proposed method was validated using a full-scale case-study arterial highway bridge in Canada. Dynamic bridge weigh in motion systems use models that can simulate the dynamic behaviour of a bridge subjected to moving traffic. Currently available models use complex and computationally expensive Moving Force Identification (MFI) methods that utilize finite element models to estimate the bridge torsional and transverse dynamic behaviour. This paper presents a novel dynamic parametric BWIM method that utilizes the experimentally estimated modal parameters for simulating the response of a bridge structure to moving loads. The estimated modes of an in-situ structure inherently capture the true bridge behaviour for any generalized geometry, boundary conditions and load position. Therefore, it enables the complex torsional and transverse bending behaviour of the bridge to be captured. In this paper, the mathematical derivation of the analytical model is presented in detail, then model calibration and weighing procedures are outlined, followed by the validation of the proposed method using a full-scale case study arterial highway bridge in the Canadian Province of New Brunswick. The proposed dynamic BWIM method offers a novel solution for the development of real-time BWIM systems that is efficient to calibrate and accurate in vehicle identification. [ABSTRACT FROM AUTHOR]

There is strong evidence for climate change leading to a rise in temperatures and a change in precipitation trends. These environmental changes pose a threat to pavement infrastructure worldwide. Therefore, it is necessary to modify pavement design procedures to consider climate change. In addition, it is necessary to consider suitable pavement materials for future climate. The objective of this study is to develop a framework for selecting an appropriate adaptation strategy to mitigate climate change impact. To fulfill this, the influence of climate change on long-term pavement performance in Canada has been quantified over sixteen Canadian pavement sections located over various provinces in Canada. In addition, the fundamental causes of pavement deterioration due to climate change were determined using ten different climate change models. Various adaptation strategies such as upgrading asphalt binder grade, increasing the thickness of asphaltic concrete layer, increasing the base layer thickness, and using stabilized base layers were analyzed to reduce pavement deterioration and to extend the service life of the pavement. Unlike the other studies, pavement temperatures were determined using Enhanced Integrated Climate Model (EICM) to determine the change in binder grade for the future climate in the adaptation process. The study found that by 2070 all examined locations will require an upgrade in binder grade and the majority will require an upgrade in mixture gradation. Furthermore, the east and west coast will be more vulnerable to climate change and require additional measures in comparison to Central Canada. Newfoundland and Prince Edward Island are the only locations that will need to consider a change in asphalt thickness while British Columbia is the only location eventually requiring a stabilized base. This study emphasizes the necessity of climate change adaptation strategies for Canadian asphaltic concrete pavements. [Display omitted] • Different combinations of adaptation strategies are necessary at each location. • The Canadian coasts generally require more adaptation measures than Central Canada. • By 2070, all Canadian provinces will require an upgrade in asphalt binder. [ABSTRACT FROM AUTHOR]

[Display omitted] • An innovative method for prion recovery from swabs was developed. • Recovery of prions decreased as swab-drying time was increased. • Recovery of CWD prions from stainless steel and glass was approximately 30%. • RT-QuIC enhanced CWD prion detection by 4 orders of magnitude. • Surface-recovered CWD prion was sufficient for efficient RT-QuIC detection. Chronic wasting disease (CWD) has been identified in 30 states in the United States, four provinces in Canada, and recently emerged in Scandinavia. The association of CWD prions with environmental materials such as soil, plants, and surfaces may enhance the persistence of CWD prion infectivity in the environment exacerbating disease transmission. Identifying and quantifying CWD prions in the environment is significant for prion monitoring and disease transmission control. A systematic method for CWD prion quantification from associated environmental materials, however, does not exist. In this study, we developed an innovative method for extracting prions from swabs and recovering CWD prions swabbed from different types of surfaces including glass, stainless steel, and wood. We found that samples dried on swabs were unfavorable for prion extraction, with the greatest prion recovery from wet swabs. Using this swabbing technique, the recovery of CWD prions dried to glass or stainless steel was approximately 30% in most cases, whereas that from wood was undetectable by conventional prion immunodetection techniques. Real-time quake-induced conversion (RT-QuIC) analysis of these same samples resulted in an increase of the detection limit of CWD prions from stainless steel by 4 orders of magnitude. More importantly, the RT-QuIC detection of CWD prions recovered from stainless steel surfaces using this method was similar to the original CWD prion load applied to the surface. This combined surface swabbing and RT-QuIC detection method provides an ultrasensitive means for prion detection across many settings and applications. [ABSTRACT FROM AUTHOR]

In terms of energy resources, Canada is an important player on the world scene. However, the energy systems of the Canadian provinces and territories are much diversified and a national energy strategy is missing in order to optimize the management of energy systems. The objective of this paper is twofold. First, we introduce TIMES-Canada, a new multi-regional energy model that has been developed using the most advanced TIMES optimization modeling framework, while keeping a very high level of details in the database (5000 specific technologies; 400 commodities) compared with other Canadian energy models. Second, we define and analyze possible futures for the Canadian integrated energy system on a 2050 horizon, under five different baselines: a Reference scenario as well as four alternate scenarios corresponding to different oil prices (Low and High) and socio-economic growth trends (Slow and Fast). In our Reference scenario, we show that the Canadian final energy consumption is expected to increase by 43% between 2007 and 2050. The Fast scenario leads to the maximum increase compared with the Reference scenario (21% in 2050). In all scenarios, oil products will continue to dominate on the long term, although in a decreasing proportion over time (from 43% in 2007 to 29% in 2050) in favor of electricity (31% of the additional demand in 2050) and biomass/biofuels. Regarding the corresponding optimal energy production paths, we illustrate two main trends: (1) a gradual replacement of onshore conventional oil & gas sources by unconventional and offshore sources (oil sands is expected to represent half of the production in 2050), and (2) a significant penetration of renewables in the electricity mix is shown after 2035 due to increases in oil import prices and decreases in renewable technology costs. The development and calibration of such a detailed technology-rich model represent an important contribution for Canada: TIMES-Canada is the only optimization model covering in details the large diversity of provincial energy systems on a long term horizon. [ABSTRACT FROM AUTHOR]

Life cycle inventory (LCI) data gaps present a crucial challenge in research and development using life cycle assessment (LCA). The present study addresses this challenge by using optimized Artificial Neural Networks (ANNs). ANN's adjustable parameters (i.e. topology and hyperparameters) significantly affect prediction capability. Thus, the optimality of those parameters is of paramount importance. However, performing an optimization on the entire ANN's adjustable parameters is computationally demanding, which may result in an intractable problem. To tackle this challenge, the present study proposes a hybrid approach using heuristics and Genetic Algorithm to systematically design optimal ANNs in a tractable fashion. The proposed approach is then assessed through the prediction of data gaps in the Canadian fuel LCI database, GHGenius (an open-access tool for modeling Canadian fuel pathways). This is achieved using an automation workflow that extracts LCI data from GHGenius at the fuel/province/unit process level. It is found that the resulting optimal ANNs not only are accurate in predicting data to fill CO 2 -eq emissions data gaps for unit processes present in the Canadian fuel life cycles but also possess shallower hidden topologies. These salient results are ascribed to the impacts of the input layer on the optimal network. In particular, input layers comprised of categorical and numerical features lead to enhancement of network prediction and/or shallower hidden topology for optimal ANNs. Taken altogether, the present study proposes, implements, and validates a systematic framework to tractably design optimal ANNs for predicting data to fill data gaps in LCI databases. In addition, this study quantifies average contributions of each unit process present in the Canadian fuel life cycles, including fossil-based and renewable pathways, to total CO 2 -eq emissions, which is of particular interest in cut-off analysis. [Display omitted] • Contributions of unit processes of fuel pathways to net emissions are determined. • A tractable approach is proposed to optimally design ANNs to fill data gaps. • The combination of categorical and numerical attributes improves ANNs' optimality. • Emission data gaps are estimated using optimal Artificial Neural Networks (ANNs). [ABSTRACT FROM AUTHOR]

Abstract: We describe a backward-time Lagrangian air quality model based on time-reversed, stochastic particle trajectories. The model simulates the transport of air parcels backward in time using ensembles of fictitious particles with stochastic motions generated from the Stochastic Time-Inverted Lagrangian Transport model (STILT). Due to the fact that STILT was originally developed out of the HYSPLIT lineage, the model leverages previous work () that implemented within HYSPLIT a chemical scheme (CB4). Chemical transformations according to the CB4 scheme are calculated along trajectories identified by the backward-time simulations. This approach opens up several key advantages: 1) exclusive focus upon air parcels that affect the receptor''s air quality; 2) the separation of transport processes—elucidated by backward-time trajectories—from chemical reactions that enables implications of multiple emission scenarios to be probed; 3) the potential to incorporate detailed sub-gridscale mixing and transport phenomena that are not tied to Eulerian gridcells. The model was used to simulate concentrations of air quality-relevant species (O3 and NO x ) at eight measurement sites in the Canadian province of Ontario. The model-predicted concentrations were compared with observations, and comparisons show that simulated O3 concentrations usually agree well with observations across sites in rural areas, small towns, and big urban regions. Furthermore, the backward-time model showed improved performance over the previous approach involving forward-time particle trajectories, especially for O3. However, the model under-estimated NO x at sites away from the big cities, possibly due to the inability of the coarsely gridded emission grids to resolve fine-scale NO x sources. Influences of cross-border transport of U.S. emission sources on the test sites were investigated using the model by turning off anthropogenic and natural U.S. emission sources. The model results suggest that total U.S. emissions contributed more than 30% of O3 concentrations at the target sites and that over half of all hours during the simulation period were affected either by anthropogenic or natural emissions from the U.S. sources, indicating the importance of U.S. sources for air quality across Ontario. [Copyright &y& Elsevier]

Objectives: The study sought to measure the prevalence, disease burden, and determinants of mortality in geriatric adults with congenital heart disease (ACHD). Background: The population of ACHD is increasing and aging. The geriatric ACHD population has yet to be characterized. Methods: Population-based cohort study using the Quebec Congenital Heart Disease Database of all patients with congenital heart disease coming into contact with the Quebec healthcare system between 1983 and 2005. Subjects with specific diagnoses of congenital heart disease and age 65 years at time of entry into the cohort were followed for up to 15 years. The primary outcome was all-cause mortality. Results: The geriatric ACHD cohort consisted of 3,239 patients. From 1990 to 2005, the prevalence of ACHD in older adults remained constant from 3.8 to 3.7 per 1,000 indexed to the general population (prevalence odds ratio: 0.98; 95% confidence interval [CI]: 0.93 to 1.03). The age-stratified population prevalence of ACHD was similar in older and younger adults. The most common types of congenital heart disease lesions in older adults were shunt lesions (60%), followed by valvular lesions (37%) and severe congenital heart lesions (3%). Type of ACHD and ACHD-related complications had a minor impact on mortality, which was predominantly driven by acquired comorbid conditions. The most powerful predictors of mortality in the Cox proportional hazards model were: dementia (hazard ratio [HR]: 3.24; 95% CI: 1.53 to 6.85), gastrointestinal bleed (HR: 2.79; 95% CI: 1.66 to 4.69), and chronic kidney disease (HR: 2.50; 95% CI: 1.72 to 3.65). Conclusions: The prevalence of geriatric ACHD is substantial, although severe lesions remain uncommon. ACHD patients that live long enough acquire general medical comorbidities, which are the pre-eminent determinants of their mortality. [ABSTRACT FROM AUTHOR]

Abstract: Estimating the effect of tuition fee increases on demand for a university education is complicated by the potential endogeneity of tuition fees. The relative homogeneity of university tuition fees within Canadian provinces and the role of provincial governments in university funding and policies, provides an opportunity to use changes in the political party in power to identify plausibly exogenous changes in tuition fees. System estimates that take into account endogeneity of fees show large effects relative to single equation estimates, and to previous Canadian studies – a C$1000 increase in university tuition fees is estimated to reduce the enrolment rate by between 2.5 and 5 percentage points. [Copyright &y& Elsevier]

Abstract: Data clustering consists of a group of procedures used to collect similar entries or data points within a set into clusters. No existing clustering technique considers entries sequentially in time. In some cases, it is desirable to generate clusters that represent a segment of a time-ordered data set. For these purposes, an order-specific clustering algorithm is proposed. The proposed algorithm employs representative load curves to describe the clusters it generates. The capabilities of the order-specific clustering algorithm are demonstrated on a case study using electricity demand data for the province of Ontario, Canada. Two different applications of the clustering algorithm on this data set are given to demonstrate the effect of error threshold values on the formation of clusters. An analysis of the error for each of these clustering applications is presented. [Copyright &y& Elsevier]

• Hydro-Québec can provide annual storage ranging from 3 to 6 TW h for high VRE markets. • Price arbitraging with high VRE markets leads to sustainable changes for hydropower. • Hydropower maintenance flexibility will gain more value with VRE growth. • Revenues from price arbitraging with high VRE markets remain low. Northeastern North America is transitioning rapidly from fossil fuel generation to variable renewable energy (VRE) sources such as wind and solar. Their integration into electricity grids poses challenges in terms of matching supply with demand. Once VRE represent a large share of installed capacity, intermittency and variability of their production will become a major issue. Hydro-Québec, the public electric utility in the Canadian province of Québec, has a large hydropower generation fleet. Its storage capacity enables adjusting hydro production, when the system needs it, to support VRE integration. In this paper, potential impacts of VRE growth within neighbouring grids are simulated through operational production management models. The results show that Hydro-Québec has the potential to facilitate this energy transition but that the current electricity market structure does not provide incentives for an optimal contribution. [ABSTRACT FROM AUTHOR]

Displacement of fossil fuels by forest bioenergy can contribute to climate change mitigation by reducing greenhouse gas (GHG) emissions. However, GHG savings are not realised until the avoided fossil emissions offset the loss of atmospheric carbon (C) that would have been sequestered if the biomass was not used for bioenergy (i.e. time to C sequestration parity). We estimated the potential for mitigating GHG emissions and the timing of these atmospheric benefits when substituting conventional natural gas (NG) with renewable natural gas (RNG) produced from different forestry feedstocks within three Canadian provinces, and assessed the uncertainty among these estimates. We calculated the GHG balance of RNG using the alternative fate of biomass and the use of NG as base-case scenarios. Immediate to long-term time to C sequestration parity was typically in the order of residues burned < mill residues < harvest residues decaying on site < salvaged trees. The potential GHG savings from using harvest and mill residues to produce RNG within the three provinces ranged from 52.4 to 77.8 Mt CO 2eq a−1. Sensitivity analyses suggest that time to C sequestration parity in the best-case scenarios relative to the baseline can be reduced up to 17 years by using harvest residues that decay rapidly (based on feedstock species, size and geographic region), and reduced up to 8 years by improving the efficiency of the thermochemical conversion process. These two considerations are key for ensuring significant GHG reductions from RNG use within a timescale that helps Canada meet its GHG mitigation targets. • Immediate GHG benefits for RNG produced with residues otherwise burned on site. • No short-term C sequestration parity time for RNG produced with forest residues. • C sequestration parity time >100 years for RNG produced with salvaged trees. • Potential net GHG savings of 52.4–77.8 Mt CO 2eq.year−1 for RNG use. [ABSTRACT FROM AUTHOR]