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Economical energy resource planning to promote sustainable urban design
No full textThis paper explores the economic aspects of distributed energy sources in a given neighborhood development. A novel methodology is proposed to achieve optimal synergy among renewable and alternative energy resources while accounting for economic and technical constraints. The methodology aims to achieve positive annual revenue to recover the capital cost investment in renewable energy, in minimum payback period. The methodology is demonstrated for a mixed-use neighborhood case study considering various scenarios of energy systems. The work proposes various tariff schemes combined with an optimal energy resource planning strategy to maximize the yearly revenue. Implementing the proposed methodology, a least payback period can be determined to address investment-related challenges faced by net-zero energy developments. The methodology allows to explore multiple near optimal combinations. Selection can be made employing suitable criteria based on specific conditions such as investment opportunities or expected minimum payback. For instance, in the demonstrated case study, a minimum payback period of 15.2 years can be achieved using non-electrical equipment (mixture of natural gas, waste-to-energy, thermal storage and grid) for space heating and domestic hot water. In this optimal case scenario, a logarithmic-based tariff scheme yields the best results
Leading welcoming and inclusive schools for newcomer students: A conceptual framework
No full textSchools with dramatically increased immigrant and refugee student populations need a systematic approach and inclusive process to ensure newcomer students, who differ in their backgrounds, languages, identities, frames of reference, prior educational experiences, abilities, interests, and belief systems, have equal opportunities and resources to thrive and succeed in schools. Based on a two-year qualitative study examining the key actors and strategies in building welcoming and inclusive schools for newcomer students, this article introduces a conceptual framework with key dimensions and strategies for guiding culturally responsive and socially just school leadership praxis.Social Sciences and Humanities Research Council, Canad
What adult electrocardiogram (ECG) diagnoses or findings are most important for advanced care paramedics to know?
No full textIntroduction: The interpretation of electrocardiograms (ECGs) is an essential competency in modern paramedicine. Although educational guidelines for paramedic ECG interpretation exist, they are broad, not evidence-based, and lack prioritization in a prehospital clinical context. We conducted this study to gain consensus among stakeholders (EMS physicians, paramedic educators, and paramedic clinicians) regarding which ECG diagnoses or findings are most important for a practising advanced care paramedic to know. Methods: This study was an internet-based Delphi survey. We purposefully sampled participants in pairs (physician/paramedic) from all 10 Canadian provinces. Individuals rated a previously developed comprehensive list of emergency ECG diagnoses or findings on the importance of paramedic recognition and impact on prehospital care using a 4-point Likert scale. The consensus was achieved with a minimum of 75% agreement on Likert rating for a single diagnosis or finding during survey rounds one to three. When consensus was not reached, stability was defined as a shift of individual ratings between rounds of 20% or less.
Results: All 20 participants completed the first and second rounds of the survey, and 17 (85%) completed three rounds. Overall, 32 (26.4%) of 121 potentially important ECG diagnoses or findings reached consensus, 2 (1.7%) reached stability and 87 (71.9%) reached neither consensus nor stability. Twenty-one (17.4%) diagnoses or findings were considered "Very Important", six (4.9%) "Important", and five (4.1%) "Minimally Important". In the first round of the survey, the mean rating of the importance of a paramedic knowing a specific ECG diagnosis or finding was lower in the physician group than the paramedic group on 85 (72%) of 118 initial diagnoses or findings.
Conclusion: We have created a list of ECG diagnoses or findings prioritized for the prehospital context that may assist paramedic educators in focusing on educational interventions. Many ECG diagnoses or findings failed to reach consensus or stability, demonstrating potential disagreement regarding clinical expectations for ECG knowledge among paramedics or physicians
Development and validation of multiplex polymerase chain reaction based diagnostic procedures for detecting eight viruses and one viroid in the Potato Nuclear Stock Certification Program
No full textThe Canadian Food Inspection Agency implements the Nuclear Stock Certification Program to ensure the production of high-quality and disease-free seed potatoes. Currently, this program employs double and triple antibody sandwich enzyme-linked immunosorbent assays (DAS- or TAS-ELISA) and return-polyacrylamide gel electrophoresis (R-PAGE) for detecting the targeted viruses and PSTVd (Potato spindle tuber viroid), respectively. Pathogen-specific antibodies for ELISA are commercially available for detecting PVM (Potato virus M), PMTV (Potato mop-top virus), PotLV (Potato latent virus), PLRV (Potato leafroll virus), PVY (Potato virus Y), PVS (Potato virus S), PVA (Potato virus A), and PVX (Potato virus X). However, the aforementioned methods are highly labour-intensive and time-consuming procedures with low sensitivity that require large sample inputs for screening. Moreover, both methods are involved with extensive experimental procedures and only allow for the screening of one pathogen each time, which further prolongs and complicates the overall diagnosing process.
In this study, multiplex PCR-based procedures were developed and validated to index the potato nuclear stock materials simultaneously in a qualitative way (“positive” or “negative”). Two mxRT-PCR (multiplex RT-PCR) and three mxRT-qPCR (multiplex real-time quantitative RT-PCR) procedures were developed for primary screening and confirmatory testing of all targeted pathogens under this program, respectively. As little as 1.0 μl of tissue sap from a microplant (in vitro plantlet) or 1.0 pg of total RNA extract was sufficient for reliable RT-PCR detection. Additionally, virus-specific RNA could be detected in RNA extracts with almost no non-specific amplification in the presence of other viral RNAs. The use of potato genome-specific primer set as an internal control provided a reference for assessing the quality of the RNA extracts and the amplification of the targeted RNAs. Furthermore, the genomes of virus and viroid isolates or strains used in this research were verified using the next-generation sequencing (NGS) technology to ensure the accuracy of the RT-PCR primers employed. All tests conducted using the mxRT-PCR and mxRT-qPCR procedures were validated using another diagnostic assay and known/unknown microplants.
Overall, the developed and validated standard multiplex PCR-based procedures in this study profoundly improved the sensitivity, specificity, efficiency, and feasibility with reductions in time and labour expenses for routine diagnostic testing of the nine targeted pathogens under the Nuclear Stock Certification Program compared to that of the currently employed ELISA and R-PAGE methods. Subsequently, the multiplex RCR-based procedures involved in this study are ready for implementation into the Nuclear Stock Certification Program. With the accurate and reliable diagnostic results generated by the multiplex PCR-based procedures, CFIA’s reputation and credibility for certifying potato nuclear stock materials will be further enhanced. Ultimately, this study promotes the trade of potato nuclear stock materials and collaboration between CFIA and the potato industries
Salmon lice should be managed before they attach to salmon: Exploring epidemiological factors affecting Lepeophtheirus salmonis abundance on salmon farms
No full textThe ectoparasite Lepeophtheirus salmonis has for decades been a serious challenge to the sustainability of salmonid aquaculture and has the potential to disrupt the ecosystem of wild salmonids. To tackle this challenge, efforts have been made to develop effective lice control strategies that deter ectoparasitic infestations on salmon farms. Infestation control can be enhanced by understanding L. salmonis population dynamics that may reveal critical points at which to intervene. Here, we investigate the impact of key parameters affecting L. salmonis population dynamics on salmon farms with a view to informing L. salmonis management. We built a system dynamics model to simulate L. salmonis populations in a hypothetical Atlantic salmon (Salmo salar L.) farm. Our model focused on three key parameters in the life cycle of L. salmonis: external pressure (rate of introduction of planktonic L. salmonis from outside the farm), attachment proportion (proportion of L. salmonis that successfully infest salmon), and treatment efficacy (proportion of L. salmonis that are killed as a result of treatment). By applying various combinations of plausible values for these three parameters, their modelled impacts on L. salmonis management were evaluated in terms of the total number of required treatments and the total infestation burden during a typical production cycle. These two modelled outcomes represent the cost of treatment and a proxy for other likely costs, such as lost growth or mortality caused by the parasite. Our results indicated that overall L. salmonis infestation levels were more sensitive to changes in the proportion of successful attachment, followed by changes in external pressure, and were least affected by changes in treatment efficacy. While attachment proportion and external pressure are involved at the pre-infestation stages in the life cycle of L. salmonis, treatment efficacy is involved in the post-infestation stages. Therefore, these findings suggest that preventing infestation before lice attach to fish is a more effective L. salmonis control strategy than treating already infested salmon. Overall, the presented results provide numerical evidence for the efficiency of prevention and support the development and application of prevention measures that have been on the rise in recent years
Hydrogen peroxide treatment and its impacts on Lepeophtheirus salmonis originating from the Bay of Fundy, Canada
No full textHydrogen peroxide (H2O2) is used to treat sea lice infections of farmed salmonids in the Atlantic and Pacific Oceans and issues with resistance to this treatment, and others are a major threat to the sustainability of the industry. The objectives of this study were to determine how H2O2 exposure affects survival and antioxidant‐related gene expression in salmon lice (Lepeophtheirus salmonis) collected from the Bay of Fundy, New Brunswick. The maximum recommended dose of H2O2 is 1,800 mg/L, while the EC50 values (with 95% CI) for the population tested were 1,486 (457, 2,515) mg/L for males and 2,126 (984, 3,268) mg/L for females. Neither temperature nor pretreatment with emamectin benzoate (EMB) impacted survival after H2O2 exposure. RT‐qPCR was performed on pre‐adult sea lice exposed to H2O2 and showed that four genes classically involved in the response to oxidative stress were unchanged between treated and control groups. Seven genes were found to be significantly upregulated in males and one in females. This is the first report on the efficacy and molecular responses of Atlantic Canada sea lice to H2O2 treatment
Temperature rise and copper exposure reduce heart mitochondrial reactive oxygen species scavenging capacity
No full textMitochondria produce and scavenge reactive oxygen species (ROS); however, whether oxidative distress due to exogenous stress arises from excessive production or impaired scavenging remains unclear. We assessed the effect of copper (Cu) and thermal stress on kinetics of ROS (H2O2) consumption in mitochondria isolated from fish heart. Mitochondria were energized with succinate, glutamate-malate or palmitoylcarnitine (PC) and incubated with 1–25 μM Cu at 11 (control) and 23 °C. We found that H2O2 consumption capacity of heart mitochondria varies with substrate and is additively reduced by temperature rise and Cu. While Cu is a potent inhibitor of H2O2 consumption in mitochondria oxidizing glutamate-malate and succinate, mitochondria oxidizing PC are resistant to the inhibitory effect of the metal. Moreover, the sensitivity of H2O2 consumption pathways to Cu depend on the substrate and are greatly impaired during oxidation of glutamate-malate. Pharmacological manipulation of mitochondrial antioxidant systems revealed that NADPH-dependent peroxidase systems are the centerpieces of ROS scavenging in heart mitochondria, with the glutathione-dependent pathway being the most prominent while catalase played a minimal role. Surprisingly, Cu is as efficacious in inhibiting thioredoxin-dependent peroxidase pathway as auranofin, a selective inhibitor of thioredoxin reductase. Taken together, our study uncovered unique mechanisms by which Cu alters mitochondrial H2O2 homeostasis including its ability to inhibit specific mitochondrial ROS scavenging pathways on a par with conventional inhibitors. Importantly, because of additive inhibitory effect on mitochondrial ROS removal mechanisms, hearts of organisms jointly exposed to Cu and thermal stress are likely at increased risk of oxidative distress
A stochastic network-based model to simulate farm-level transmission of African swine fever virus in Vietnam
No full textAfrican swine fever virus is highly contagious, and mortality rates reach up to 100% depending on the host, virus dose, and the transmission routes. The main objective of this study was to develop a network-based simulation model for the farm-level transmission of ASF virus to evaluate the impact of changes in farm connectivity on ASF spread in Vietnam. A hypothetical population of 1,000 pig farms was created and used for the network-based simulation, where each farm represented a node, and the connection between farms represented an edge. The three scenarios modelled in this way (baseline, low, and high) evaluated the impact of connectivity on disease transmission. The median number of infected farms was higher as the connectivity increased (low: 659, baseline: 968 and high: 993). In addition, we evaluated the impact of the culling strategy on the number of infected farms. A total of four scenarios were simulated depending on the timing of culling after a farm was infected. We found that the timing of culling at 16, 12, 8, and 6 weeks had resulted in a reduction of the number of median infected farms by 81.92%, 91.63%, 100%, and 100%, respectively. Finally, our evaluation of the implication of stability of ties between farms indicated that if the farms were to have the same trading partners for at least six months could significantly reduce the median number of infected farms to two (95th percentile: 413) than in the basic model. Our study showed that pig movements among farms had a significant influence on the transmission dynamics of ASF virus. In addition, we found that the either timing of culling, reduction in the number of trading partners each farm had, or decreased mean contact rate during the outbreaks were essential to prevent or stop further outbreaks.CGIA
State-space modeling for inter-site spread of sea lice with short-term population predictions
No full textAccurate predictions for sea lice abundance can have a great impact on effective management of the parasite. Sea lice data are often from multiple production cycles coming from different aquaculture sites and exhibit strong process and observation variations, presenting challenges in developing effective prediction tools. Reliable predictions of sea lice abundance on aquaculture sites can save money and efforts in organizing effective control measures. A quantitative evaluation of different methods for estimating sea lice infestation pressure on aquaculture sites was presented in a preparatory paper (Elghafghuf et al., 2020). In the current work, we used the favored method for infestation pressure and predicted future sea lice abundances on different parasitic life stages at the site level using a multivariate state-space model fitted to data from aquaculture sites located near Grand Manan Island in the Bay of Fundy, New Brunswick, Canada. We employed a rolling prediction procedure that did not require the prediction model to be refitted to the data at each time of prediction and compared our results with those from a similar approach involving re-estimation of the model at each prediction. The accuracies of predictions were assessed based on hold-out samples of data, whereby the predictions were computed without prior knowledge of these observations. The results showed that the non-updated-model procedure gave short-term (six weeks) predictions with reasonable accuracy, albeit lower prediction errors could be obtained with the updated-model approach. The performance of the non-updated-model prediction, as well as its practical and computational advantages, suggests it to be well suited for user-friendly implementation linked to underlying database. Additionally, the research quantified the contributions of predictive covariates such as infestation pressures to the sea lice predictions.Ocean Frontier InstituteCanada First Research Excellence Fun
Thermoresponsive and antifouling hydrogels as a radiative energy driven water harvesting system
No full textHygroscopic and temperature-responsive hydrogels with the potential to harvest water from air followed by its release in liquid or vapor form have seen much interest as water harvesting materials for arid regions. However, the purification of water from wastewater remains a major challenge and only a handful of technologies are being investigated for their potential to purify water from polluted resources. In this study, we explore the synthesis of antifouling and radiative heat driven water-harvesting hydrogels that are capable of absorbing clean water from resources polluted with organic waste, followed by its release, mainly in liquid form, as a function of temperature. The new thermoresponsive hydrogels are comprised of hygroscopic and antifouling vitamin B5 analogous monomers (B5AMA) and 2-(2-methoxyethoxy)ethyl methacrylate (MEO2MA) and are evaluated for their kinetics of water uptake and release capacity. The poly(B5AMA-co-MEO2MA) hydrogels are further evaluated for their ability to recycle clean water from organic polluted wastewater resources and for their potential to develop a radiative energy driven water harvesting system. The hydrogels synthesized are found to be extremely hygroscopic and can recycle 6.84 g of water per g of hydrogel (~85% water recycling efficiency) upon heating at 60 °C. The hydrogels are also extremely antifouling and can repel 1.5 × 109 bacterial cells per mL of wastewater. The water release rate of the hydrogels is dependent upon the time and temperature and can be tuned to develop a solar fueled water harvesting system