Dalhousie University
  • Halifax, NS, Canada
Recent publications
Differential settlement could be triggered by many factors within the soil strata, including frost heave, seismic activities, collapse of sinkholes, poorly compacted soil, or adjacent excavation activities. Such activities result in an uneven relaxation within the soil, forming undesirable settlements and imposing stress conditions, which are unaccounted for in the design process. Ground settlements can inflict serious, and in some cases, irreparable damage to pre-existing structures. Understanding the impact such settlements could have on structural systems is vital in developing effective preventative measures that would help mitigate such effects. Hence, this study investigates the effects of the differential settlement on a reinforced concrete framed structure by examining the structural behaviour considering different spans and heights. The nonlinear behaviour of the structure is simulated through two-dimensional (2D) frame finite element simulations. The propagation of mechanical damage within the structural members and the plastic hinge formation with respect to the induced settlements are then analyzed. The affect of ductility on the frame’s behaviour is demonstrated, and comparisons with settlement tolerances proposed in literature are drawn to assess the effectiveness of these limits.
The main objective of the research presented in this paper was to perform the analytical study to investigate the flexural capacity of the concrete beam reinforced longitudinally and laterally with glass fiber-reinforced polymers (GFRP) bars subjected to low axial compressive load. If the GFRP beam is subjected to compression due to any accidental wind or seismic load, ignoring compression during this condition might not be conservative. To characterize the flexural capacity of the beam under low axial loading—the study was performed considering the specimen with a cross-sectional size of 300 × 400 mm with a concrete grade of 40 MPa and reinforcement ratio of 4%. The analytical model was developed using PTC MATHCAD Prime to carry out the analysis for the sand coated GFRP reinforced concrete beam. From the analytical study results of a beam, the interaction diagram showed that the ultimate bending resistance of the beam decreases with the application of lower load in the range of 5–10% of its axial capacity. Further with the analytical model, a parametric study was performed to investigate the effect of reinforcement ratio, concrete strength, and axial load. As part of this ongoing research, an experimental investigation is further carried out at Dalhousie University to verify the analytical study by testing the full-scale GFRP concrete beam under Four-point bending with low axial compressive loads applied at both ends of the beam. During the time of the conference presentation, there will be more test data available to endorse the analytical behavior of the GFRP reinforced concrete beam presented in this paper.
The stiffness of concrete columns is adjusted by a factor referred to as the stiffness reduction factor or the stability resistance factor when utilizing the simplified second-order moment magnification method for designing slender reinforced concrete (RC) columns. The stiffness reduction factor of 0.75 in ACI 318, CSA A23.3, and CSA S6 was calibrated for steel-RC columns using reliability analysis to account for the variability in concrete strength, steel strength, and applied loads. The upcoming ACI 440 code adopts the same stiffness reduction factor for the design of slender glass fiber-reinforced polymer (GFRP) RC columns when using the moment magnification method. The structural reliability of slender GFRP-RC columns designed using a stiffness reduction factor of 0.75 was not evaluated despite the difference in the GFRP statistical parameters and stiffness characteristics as compared with conventional steel. The objective of this research is to conduct a reliability analysis of slender GFRP-RC columns to evaluate the reliability index associated with the use of the stiffness reduction factor and provide recommendations regarding the optimum value of the factor to meet code target safety limits. Monte Carlo simulation is used to conduct the reliability analysis. Statistical input parameters (distribution type, bias ratio, and coefficient of variation) of GFRP based on an extensive experimental database are utilized in the study. The proposed research presents a necessary step toward quantifying the safety associated with the design provisions proposed in upcoming ACI 440 code.
No previous research has examined age and sex differences in balance outcomes in individuals with chronic obstructive pulmonary disease (COPD) at risk of falls. A secondary analysis of baseline data from an ongoing trial of fall prevention in COPD was conducted. Age and sex differences were analyzed for the Berg Balance scale (BBS), Balance Evaluation System Test (BEST test) and Activities-specific Balance Confidence Scale (ABC). Overall, 223 individuals with COPD were included. Females had higher balance impairments than males [BBS: mean (SD) = 47 (8) vs. 49 (6) points; BEST test: 73 (16) vs. 80 (16) points], and a lower confidence to perform functional activities [ABC = 66 (21) vs. 77 (19)]. Compared to a younger age (50-65 years) group, age >65 years was moderately associated with poor balance control [BBS (r = - 0.37), BEST test (r = - 0.33)] and weakly with the ABC scale (r = - 0.13). After controlling for the effect of balance risk factors, age, baseline dyspnea index (BDI), and the 6-min walk test (6-MWT) explained 38% of the variability in the BBS; age, sex, BDI, and 6-MWT explained 40% of the variability in the BEST test; And BDI and the 6-MWT explained 44% of the variability in the ABC scale. This study highlights age and sex differences in balance outcomes among individuals with COPD at risk of falls. Recognition of these differences has implications for pulmonary rehabilitation and fall prevention in COPD, particularly among females and older adults.
During the first quarter of 2020, the global COVID-19 pandemic disrupted the lives of Canadians, changing the way they worked, studied, and shopped. In addition to restrictions on freedom of movement and gathering, there was confusion spread on social media platforms about points and rates of transmission. Inconsistent messaging from public health authorities and government representatives eroded public trust, despite the initially low rate of infection. This research was carried out through four cross-country surveys to explore the experience and perceptions about food retail and food service during the COVID-19 pandemic in Canada. Results suggest confusion and fear towards food provisioning. As well, telecommuting and adoption of online shopping tools drove consumer behaviour in food retail during the first wave of the pandemic. Our findings demonstrate a need for innovation in the food retailing and service sector. © 2022 The Author(s). This open access article is distributed under a Creative Commons Attribution (CC-BY) 4.0 license.
Background Despite the growing utility of cardiovascular magnetic resonance (CMR) for cardiac morphology and function, sex and age-specific normal reference values derived from large, multi-ethnic data sets are lacking. Furthermore, most available studies use a simplified tracing methodology. Using a large cohort of participants without history of cardiovascular disease (CVD) or risk factors from the Canadian Alliance for Healthy Heart and Minds, we sought to establish a robust set of reference values for ventricular and atrial parameters using an anatomically correct contouring method, and to determine the influence of age and sex on ventricular parameters. Methods and results Participants (n = 3206, 65% females; age 55.2 ± 8.4 years for females and 55.1 ± 8.8 years for men) underwent CMR using standard methods for quantitative measurements of cardiac parameters. Normal ventricular and atrial reference values are provided: (1) for males and females, (2) stratified by four age categories, and (3) for different races/ethnicities. Values are reported as absolute, indexed to body surface area, or height. Ventricular volumes and mass were significantly larger for males than females (p < 0.001). Ventricular ejection fraction was significantly diminished in males as compared to females (p < 0.001). Indexed left ventricular (LV) end-systolic, end-diastolic volumes, mass and right ventricular (RV) parameters significantly decreased as age increased for both sexes (p < 0.001). For females, but not men, mean LV and RVEF significantly increased with age (p < 0.001). Conclusion Using anatomically correct contouring methodology, we provide accurate sex and age-specific normal reference values for CMR parameters derived from the largest, multi-ethnic population free of CVD to date. Clinical trial registration ClinicalTrials.gov, NCT02220582. Registered 20 August 2014—Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT02220582 .
Background There is currently little Canadian data to assess how well traditional time-based residency training programs have prepared residents for careers in Clinical Immunology and Allergy (CIA). This study aims to identify the perceived preparedness of residents in various areas of practice upon the completion of a Canadian CIA residency training program. Methods In the summer of 2020, an electronic survey was sent to 2018 and 2019 graduates of Canadian CIA training programs by the Canadian Society of Allergy and Clinical Immunology (CSACI). Results Former residents felt well prepared in most Medical Expert areas. Residents felt less prepared for the intrinsic roles of Leader, Communicator, Collaborator, Health Advocate, Scholar, and Professional. The majority of the intrinsic competencies were learned through mentorship and on the job after finishing training. Conclusions Upon completion of training, Canadian CIA residents felt well prepared for many competencies, particularly in Medical Expert areas. Training programs may wish to focus on various intrinsic competencies in order to better prepare residents for transition to practice. Academic half-day was not identified as a primary learning centre for intrinsic competencies, suggesting that new teaching strategies may be required.
Background Variable disease progression confounds accurate prognosis in Fabry disease. Evidence supports the long-term benefit of early intervention with disease-specific therapy, but current guidelines recommend treatment initiation based on signs that may present too late to avoid irreversible organ damage. Findings from the ‘PRoposing Early Disease Indicators for Clinical Tracking in Fabry Disease’ (PREDICT-FD) initiative included expert consensus on 27 early indicators of disease progression in Fabry disease and on drivers of and barriers to treatment initiation in Fabry disease. Here, we compared the PREDICT-FD indicators with guidance from the European Fabry Working Group and various national guidelines to identify differences in signs supporting treatment initiation and how guidelines themselves might affect initiation. Finally, anonymized patient histories were reviewed by PREDICT-FD experts to determine whether PREDICT-FD indicators supported earlier treatment than existing guidance. Results Current guidelines generally aligned with PREDICT-FD on indicators of renal involvement, but most lacked specificity regarding cardiac indicators. The prognostic significance of neurological indicators such as white matter lesions (excluded by PREDICT-FD) was questioned in some guidelines and excluded from most. Some PREDICT-FD patient-reported signs (e.g., febrile crises) did not feature elsewhere. Key drivers of treatment initiation in PREDICT-FD were: (A) male sex, young age, and clinical findings (e.g., severe pain, organ involvement), (B) improving clinical outcomes and preventing disease progression, and (C) a family history of Fabry disease (especially if outcomes were severe). All guidelines aligned with (A) and several advocated therapy for asymptomatic male patients. There was scant evidence of (B) in current guidance: for example, no countries mandated ancillary symptomatic therapy, and no guidance advocated familial screening with (C) when diagnosis was confirmed. Barriers were misdiagnosis and a lack of biomarkers to inform timing of treatment. Review of patient histories generally found equal or greater support for treatment initiation with PREDICT-FD indicators than with other guidelines and revealed that the same case and guideline criteria often yielded different treatment recommendations. Conclusions Wider adoption of PREDICT-FD indicators at a national level could promote earlier treatment in Fabry disease. Clearer, more concise guidance is needed to harmonize treatment initiation in Fabry disease internationally.
Background Prolidase deficiency (PD) is an autosomal recessive inborn multisystemic disease caused by mutations in the PEPD gene encoding the enzyme prolidase D, leading to defects in turnover of proline-containing proteins, such as collagen. PD is categorized as a metabolic disease, but also as an inborn error of immunity. PD presents with a range of findings including dysmorphic features, intellectual disabilities, recurrent infections, intractable skin ulceration, autoimmunity, and splenomegaly. Despite symptoms of immune dysregulation, only very limited immunologic assessments have been reported and standard therapies for PD have not been described. We report twin females with PD, including comprehensive immunologic profiles and treatment modalities used. Case presentation Patient 1 had recurrent infections in childhood. At age 13, she presented with telangiectasia, followed by painful, refractory skin ulcerations on her lower limbs, where skin biopsy excluded vasculitis. She had typical dysmorphic features of PD. Next-generation sequencing revealed pathogenic compound heterozygous mutations (premature stop codons) in the PEPD gene. Patient 2 had the same mutations, typical PD facial features, atopy, and telangiectasias, but no skin ulceration. Both patients had imidodipeptiduria. Lymphocyte subset analysis revealed low-normal frequency of T reg cells and decreased frequency of expression of the checkpoint molecule CTLA-4 in CD4 ⁺ T EM cells. Analysis of Th1, Th2, and Th17 profiles revealed increased inflammatory IL-17 ⁺ CD8 ⁺ T EM cells in both patients and overexpression of the activation marker HLA-DR on CD4 ⁺ T EM cells, reflecting a highly activated proinflammatory state. Neither PD patient had specific antibody deficiencies despite low CD4 ⁺ CXCR5 ⁺ T fh cells and low class-switched memory B cells. Plasma IL-18 levels were exceptionally high. Conclusions Immunologic abnormalities including skewed frequencies of activated inflammatory CD4 ⁺ and CD8 ⁺ T EM cells, decreased CTLA-4 expression, and defects in memory B cells may be a feature of immune dysregulation associated with PD; however, a larger sample size is required to validate these findings. The high IL-18 plasma levels suggest underlying autoinflammatory processes.
Background Tonsillectomy is a commonly performed procedure in Canada. The rate of occult malignancy is rare in adult and pediatric populations. At present, no guidelines exist surrounding the need for routine histopathological evaluation of tonsil specimens when no malignancy is suspected. Methods We sent a confidential online survey to active members of the Canadian Society of Otolaryngology – Head and Neck Surgery (CSO-HNS) about their current tonsillectomy practice and beliefs surrounding the need for routine histopathological evaluation of tonsillectomy specimens when no malignancy is suspected. We used Opinio survey software for data collection and descriptive statistics. Results 95 participants completed our survey (response rate 19.3%). Most participants reported performing both adult and pediatric tonsillectomies. When no malignancy is suspected, participant responses were split between whether they send tonsil specimens in pediatrics only (4.2%), in adults only (31.6%), or not sending specimens (29.5%). Half of the participants reported that routinely sending specimens to rule out occult malignancy is an institutional policy. Approximately 75% of participants were in favour of removing this practice in both the pediatric and adult populations. Conclusion Eliminating the practice of automatically sending tonsil specimens for histopathological evaluation when no malignancy is suspected was supported by the majority of study participants. This is in keeping with Choosing Wisely, a campaign designed to facilitate conversations about unnecessary medical tests and procedures. Institutional change is likely required in order to alter this practice. Graphical Abstract
Accumulating evidence suggests that autophagy dysfunction plays a critical role in myocardial ischemia/reperfusion (I/R) injury. However, the underling mechanism of malfunctional autophagy in the cardiomyocytes subjected to I/R has not been well defined. As a result, there is no effective therapeutic option by targeting autophagy to prevent myocardial I/R injury. Here, we used both an in vitro and an in vivo I/R model to monitor autophagic flux in the cardiomyocytes, by exposing neonatal rat ventricular myocytes to hypoxia/reoxygenation and by subjecting mice to I/R, respectively. We observed that the autophagic flux in the cardiomyocytes subjected to I/R was blocked in both in vitro and in vivo models. Down-regulating a lysosomal cationic channel, TRPML1, markedly restored the blocked myocardial autophagic flux induced by I/R, demonstrating that TRPML1 directly contributes to the blocked autophagic flux in the cardiomyocytes subjected to I/R. Mechanistically, TRPML1 is activated secondary to ROS elevation following ischemia/reperfusion, which in turn induces the release of lysosomal zinc into the cytosol and ultimately blocks the autophagic flux in cardiomyocytes, presumably by disrupting the fusion between autophagosomes and lysosomes. As a result, the inhibited myocardial autophagic flux induced by TRPML1 disrupted mitochondria turnover and resulted in mass accumulation of damaged mitochondria and further ROS release, which directly led to cardiomyocyte death. More importantly, pharmacological and genetic inhibition of TRPML1 channels greatly reduced infarct size and rescued heart function in mice subjected to I/R in vivo by restoring impaired myocardial autophagy. In summary, our study demonstrates that secondary to ROS elevation, activation of TRPML1 results in autophagy inhibition in the cardiomyocytes subjected to I/R, which directly leads to cardiomyocyte death by disrupting mitochondria turnover. Therefore, targeting TRPML1 represents a novel therapeutic strategy to protect against myocardial I/R injury.
Background and objectives Safety and effectiveness concerns may preclude physicians from recommending vaccination in mild/moderate inborn errors of immunity (IEI). This study describes attitudes and practices regarding vaccination among physicians who care for patients with mild/moderate B cell or mild/moderate combined immunodeficiencies (CID) and vaccination completeness among patients diagnosed with IEIs. Methods Canadian physicians caring for children with IEI were surveyed about attitudes and practices regarding vaccination in mild/moderate IEI. Following informed consent, immunization records of pediatric patients with IEI evaluated before 7 years of age were reviewed. Vaccine completeness was defined at age 2 years as 4 doses of diphtheria-tetanus-pertussis (DTaP), 3 doses pneumococcal conjugate (PCV), and 1 dose measles-mumps-rubella (MMR) vaccines. At 7 years 5 doses of DTP and 2 doses MMR were required. Results Forty-five physicians from 8 provinces completed the survey. Most recommended inactivated vaccines for B cell deficiency: (84% (38/45) and CID (73% (33/45). Fewer recommended live attenuated vaccines (B cell: 53% (24/45), CID 31% (14/45)). Of 96 patients with IEI recruited across 7 centers, vaccination completeness at age 2 was 25/43 (58%) for predominantly antibody, 3/13 (23%) for CID, 7/35 (20%) for CID with syndromic features, and 4/4 (100%) for innate/phagocyte defects. Completeness at age 7 was 15%, 17%, 5%, and 33%, respectively. Conclusion Most physicians surveyed recommended inactivated vaccines in children with mild to moderate IEI. Vaccine completeness for all IEI was low, particularly at age 7. Further studies should address the reasons for low vaccine uptake among children with IEI and whether those with mild-moderate IEI, where vaccination is recommended, eventually receive all indicated vaccines.
Objective People experiencing homelessness often encounter progressive illness(es) earlier and are at increased risk of mortality compared to the housed population. There are limited resources available to serve this population at the end-of-life (EOL). The purpose of this study was to gain insight into preferences for the EOL and end-of-life care for people experiencing homelessness. Utilizing an interpretive phenomenology methodology and the theoretical lens of critical social theory, we present results from 3 participants interviewed from August to October 2020, with current or previous experience of homelessness and a diagnosis of advanced disease/progressive life-threatening illness. Results A key finding focused on the existential struggle experienced by the participants in that they did not care if they lived or died. The participants described dying alone as a bad or undignified way to die and instead valued an EOL experience that was without suffering, surrounded by those who love them, and in a familiar place, wherever that may be. This study serves to highlight the need for improvements to meet the health care and social justice needs of people experiencing homelessness by ensuring equitable, humanistic health and end-of-life care, particularly during the context of the COVID-19 pandemic.
Background Patient registries provide long-term, real-world evidence that aids the understanding of the natural history and progression of disease, and the effects of treatment on large patient populations with rare diseases. The year 2021 marks the 20th anniversary of the Fabry Outcome Survey (FOS), an international, multicenter, observational registry (NCT03289065). The primary aims of FOS are to broaden the understanding of Fabry disease (FD), an X-linked lysosomal storage disorder, and to improve the clinical management of affected patients. Here, we review the history of FOS and the analyses and publications disseminated from the registry, and we discuss the contributions FOS studies have made in understanding FD. Results FOS was initiated in April 2001 and, as of January 2021, 4484 patients with a confirmed diagnosis and patient informed consent have been enrolled from 144 centers across 26 countries. Data from FOS have been published in nearly 60 manuscripts on a wide variety of topics relevant to FD. Analyses of FOS data have investigated the long-term effectiveness and safety of enzyme replacement therapy (ERT) with agalsidase alfa and its effects on morbidity and mortality, as well as the benefits of prompt and early treatment with agalsidase alfa on the progression of cardiomyopathy and the decline in renal function associated with FD. Based on analyses of FOS data, ERT with agalsidase alfa has also been shown to improve additional signs and symptoms of FD experienced by patients. FOS data analyses have provided a better understanding of the natural history of FD and the specific populations of women, children, and the elderly, and have provided practical tools for the study of FD. FOS has also provided methodology and criteria for assessing disease severity which contributed to the continuous development of medical practice in FD and has largely improved our understanding of the challenges and needs of long-term data collection in rare diseases, aiding in future rare disease real-world evidence studies. Conclusion FOS over the last 20 years has substantially increased the scientific knowledge around improved patient management of FD and continues to expand our understanding of this rare disease.
Graph neural networks are attractive for learning properties of atomic structures thanks to their intuitive graph encoding of atoms and bonds. However, conventional encoding does not include angular information, which is critical for describing atomic arrangements in disordered systems. In this work, we extend the recently proposed ALIGNN (Atomistic Line Graph Neural Network) encoding, which incorporates bond angles, to also include dihedral angles (ALIGNN-d). This simple extension leads to a memory-efficient graph representation that captures the complete geometry of atomic structures. ALIGNN-d is applied to predict the infrared optical response of dynamically disordered Cu(II) aqua complexes, leveraging the intrinsic interpretability to elucidate the relative contributions of individual structural components. Bond and dihedral angles are found to be critical contributors to the fine structure of the absorption response, with distortions that represent transitions between more common geometries exhibiting the strongest absorption intensity. Future directions for further development of ALIGNN-d are discussed.
Introduction Several studies have shown anti-tumor effects of components present in cannabis in different models. Unfortunately, little is known about the potential anti-tumoral effects of most compounds present in cannabis in bladder cancer and how these compounds could potentially positively or negatively impact the actions of chemotherapeutic agents. Our study aims to evaluate the effects of a compound found in Cannabis sativa that has not been extensively studied to date, cannflavin A, in bladder cancer cell lines. We aimed to identify whether cannflavin A co-treatment with agents commonly used to treat bladder cancer, such as gemcitabine and cisplatin, is able to produce synergistic effects. We also evaluated whether co-treatment of cannflavin A with various cannabinoids could produce synergistic effects. Methods Two transitional cell carcinoma cell lines were used to assess the cytotoxic effects of the flavonoid cannflavin A up to 100 μM. We tested the potential synergistic cytotoxic effects of cannflavin A with gemcitabine (up to 100 nM), cisplatin (up to 100 μM), and cannabinoids (up to 10 μM). We also evaluated the activation of the apoptotic cascade using annexin V and whether cannflavin A has the ability to reduce invasion using a Matrigel assay. Results Cell viability of bladder cancer cell lines was affected in a concentration-dependent fashion in response to cannflavin A, and its combination with gemcitabine or cisplatin induced differential responses—from antagonistic to additive—and synergism was also observed in some instances, depending on the concentrations and drugs used. Cannflavin A also activated apoptosis via caspase 3 cleavage and was able to reduce invasion by 50%. Interestingly, cannflavin A displayed synergistic properties with other cannabinoids like Δ ⁹ -tetrahydrocannabinol, cannabidiol, cannabichromene, and cannabivarin in the bladder cancer cell lines. Discussion Our results indicate that compounds from Cannabis sativa other than cannabinoids, like the flavonoid cannflavin A, can be cytotoxic to human bladder transitional carcinoma cells and that this compound can exert synergistic effects when combined with other agents. In vivo studies will be needed to confirm the activity of cannflavin A as a potential agent for bladder cancer treatment.
We propose a microring resonator with Bragg reflection waveguide (BRW) capable of simultaneously establishing the quasi-phase-matching, Bragg, and resonance conditions to achieve optical second-harmonic generation (SHG). Using numerical simulations, we suggest a comprehensive design procedure for a monolithic AlGaAs BRW microring. Due to the sensitive nature of BRW-based devices to material and fabrication tolerances, precise thermo-optic tuning method is proposed. It is shown that the designed structure can be thermally tuned in such a way that by only 6 °C, it can be switched to adjacent working wavelengths. Furthermore, being able to design microrings with different radii on the same wafer for SHG investigation is another advantage of our proposed device.
Background Children living with chronic comorbid conditions are at increased risk for severe COVID-19, though there is limited evidence regarding the risks associated with specific conditions and which children may benefit from targeted COVID-19 therapies. The objective of this study was to identify factors associated with severe disease among hospitalized children with COVID-19 in Canada. Methods We conducted a national prospective study on hospitalized children with microbiologically confirmed SARS-CoV-2 infection via the Canadian Paediatric Surveillance Program (CPSP) from April 2020–May 2021. Cases were reported voluntarily by a network of >2800 paediatricians. Hospitalizations were classified as COVID-19-related, incidental infection, or infection control/social admissions. Severe disease (among COVID-19-related hospitalizations only) was defined as disease requiring intensive care, ventilatory or hemodynamic support, select organ system complications, or death. Risk factors for severe disease were identified using multivariable Poisson regression, adjusting for age, sex, concomitant infections, and timing of hospitalization. Findings We identified 544 children hospitalized with SARS-CoV-2 infection, including 60·7% with COVID-19-related disease and 39·3% with incidental infection or infection control/social admissions. Among COVID-19-related hospitalizations (n=330), the median age was 1·9 years (IQR 0·1–13·3) and 43·0% had chronic comorbid conditions. Severe disease occurred in 29·7% of COVID-19-related hospitalizations (n=98/330 including 60 admitted to intensive care), most frequently among children aged 2-4 years (48·7%) and 12-17 years (41·3%). Comorbid conditions associated with severe disease included pre-existing technology dependence requirements (adjusted risk ratio [aRR] 2·01, 95% confidence interval [CI] 1·37-2·95), body mass index Z-scores ≥3 (aRR 1·90, 95% CI 1·10-3·28), neurologic conditions (e.g. epilepsy and select chromosomal/genetic conditions) (aRR 1·84, 95% CI 1·32-2·57), and pulmonary conditions (e.g. bronchopulmonary dysplasia and uncontrolled asthma) (aRR 1·63, 95% CI 1·12-2·39). Interpretation While severe outcomes were detected at all ages and among patients with and without comorbidities, neurologic and pulmonary conditions as well as technology dependence were associated with increased risk of severe COVID-19. These findings may help guide vaccination programs and prioritize targeted COVID-19 therapies for children. Funding Financial support for the CPSP was received from the Public Health Agency of Canada.
The purpose of this manuscript is to review LCA studies of organic field crops to identify best practices in collecting life cycle inventory data. Previous LCA studies of organic field crops from 2010 to 2021 were identified and data were collected in the following categories: 1) crops studied, 2) geographical locations and spatial resolution, 3) life cycle inventory data collected, 4) models used for estimating changes in soil carbon and for estimating field-level emissions and their associated data inputs. Based on these data, recommendations were made with respect to the best data to collect, and emissions and soil carbon models to use for LCAs of organic field crops. Based on the assessment of LCI inventory data collected for activities, inputs and emissions modelling, a list of recommendations for future LCI data collection for organic field crops was tabulated. This included the data that should come directly from farmers, as well as data from secondary sources, and the specific models that can be used for soil carbon and emissions modelling. The recommendations made based on the LCI data identified can be used to inform data collection for high quality, regionally resolved LCAs of organic field crop production.
Background Although vaccination against Streptococcus pneumoniae infections (such as invasive pneumococcal disease (IPD)) are available, challenges remain in prevention efforts. Moreover, downstream sequelae in children is relatively unknown. Thus, we aimed to evaluate short and long-term health outcomes among children with IPD. Methods Analysis of Streptococcus pneumoniae positive isolates from sterile body sites in children (0–17 years) in Alberta (Canada) from 1999 to 2019 was performed retrospectively (n=888). Cases were age and sex-matched to hospitalized population controls. Linkage to administrative health datasets was done to determine comorbidities and healthcare related outcomes. Cox proportional hazards were used to assess differences in time to mortality and hospitalisation between cases and controls in short (<30-day), intermediate (30–90 day), long-term (>90-day) follow-up. Findings Proportionally more deaths occurred in cases (4.8 deaths/1000 person-years (PY)) than controls (2.7 deaths/1000 PY), leading to a significant adjusted hazard ratio (aHR) of 1.80 (95% CI 1.22–2.64). This increased risk of death was influenced primarily by short-term mortality (319 vs 36 deaths/1000 PY in cases vs controls respectively, aHR 8.78 [95% CI 3.33–23.18]), as no differences were seen in intermediate (14 vs 7 deaths/1000 PY; aHR 2.03, 95% CI 0.41–10.04) or long-term time intervals (2.4 vs 2.3 deaths/1000 PY, aHR 1.03, 95% CI 0.63–1.69). Interpretation IPD continues to negatively impact survival in children despite vaccination. Although long-term impact on mortality and hospitalisations may not be substantial, the immediate effects of IPD are significant. Funding This work was supported by grants-in-aid from Pfizer Canada and Wyeth Canada Inc all to GJT.
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Manuel Mattheisen
  • Department of Community Health & Epidemiology
Karina Top
  • Departments of Pediatrics and Community Health & Epidemiology
Robert Wingate Lee
  • Department of Biology
Deborah Adewole
  • Department of Animal Science and Aquaculture
6100 University Ave, Suite 5010, PO Box 15000, B3H 4R2, Halifax, NS, Canada
Head of institution
Deep Saini