| 1. |
- Niemi, MEK, et al.
(author)
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- 2021
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swepub:Mat__t
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| 2. |
- Kanai, M, et al.
(author)
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- 2023
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swepub:Mat__t
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| 3. |
- Beal, Jacob, et al.
(author)
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Robust estimation of bacterial cell count from optical density
- 2020
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In: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Journal article (peer-reviewed)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 4. |
- Asihene, Elvis, et al.
(author)
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Toward the Detection of Oil Spills in Newly Formed Sea Ice Using C-Band Multipolarization Radar
- 2022
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In: IEEE Transactions on Geoscience and Remote Sensing. - : IEEE Geoscience and Remote Sensing Society. - 0196-2892 .- 1558-0644. ; 60
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Journal article (peer-reviewed)abstract
- Oil spills in the Arctic are becoming more likely as shipping traffic increases in response to climate-related sea ice loss. To improve oil spill detection capability, we used a controlled mesocosm to analyze the multipolarized C-band backscatter response of oil in newly formed sea ice (NI). Artificial sea ice was grown in two cylindrical tubs at the Sea-ice Environmental Research Facility, University of Manitoba. The sea ice physical characteristics, including surface roughness, thickness, temperature, and salinity, were measured before and after oil injection below the ice sheet. Time-series C-band radar backscatter measurements detected the differences in the sea ice evolution and oil migration to the sea ice surface in the oil-contaminated tub, which was compared to uncontaminated ice in a control tub. Immediately prior to the presence of oil on the ice surface, the copolarized backscatter is increased by 13-dB local maximum, while the cross-polarized backscatter is decreased by 9-dB. Ice physical properties suggest that the local backscatter maximum and minimum, which occurred immediately before oil migrated onto the surface, were related to a combination of brine and oil upward migration. The findings of this work provide a baseline data interpretation for oil detection in the Arctic Ocean using current and future C-band multipolarization radar satellites.
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| 5. |
- Balabanski, Anna H., et al.
(author)
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Incidence of stroke in indigenous populations of countries with a very high human development index : a systematic review
- 2024
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In: Neurology. - : American Academy of Neurology. - 0028-3878 .- 1526-632X. ; 102:5
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Research review (peer-reviewed)abstract
- Background and objectives: Cardiovascular disease contributes significantly to disease burden among many Indigenous populations. However, data on stroke incidence in Indigenous populations are sparse. We aimed to investigate what is known of stroke incidence in Indigenous populations of countries with a very high Human Development Index (HDI), locating the research in the broader context of Indigenous health.Methods: We identified population-based stroke incidence studies published between 1990 and 2022 among Indigenous adult populations of developed countries using PubMed, Embase, and Global Health databases, without language restriction. We excluded non-peer-reviewed sources, studies with fewer than 10 Indigenous people, or not covering a 35- to 64-year minimum age range. Two reviewers independently screened titles, abstracts, and full-text articles and extracted data. We assessed quality using "gold standard" criteria for population-based stroke incidence studies, the Newcastle-Ottawa Scale for risk of bias, and CONSIDER criteria for reporting of Indigenous health research. An Indigenous Advisory Board provided oversight for the study.Results: From 13,041 publications screened, 24 studies (19 full-text articles, 5 abstracts) from 7 countries met the inclusion criteria. Age-standardized stroke incidence rate ratios were greater in Aboriginal and Torres Strait Islander Australians (1.7-3.2), American Indians (1.2), Sámi of Sweden/Norway (1.08-2.14), and Singaporean Malay (1.7-1.9), compared with respective non-Indigenous populations. Studies had substantial heterogeneity in design and risk of bias. Attack rates, male-female rate ratios, and time trends are reported where available. Few investigators reported Indigenous stakeholder involvement, with few studies meeting any of the CONSIDER criteria for research among Indigenous populations.Discussion: In countries with a very high HDI, there are notable, albeit varying, disparities in stroke incidence between Indigenous and non-Indigenous populations, although there are gaps in data availability and quality. A greater understanding of stroke incidence is imperative for informing effective societal responses to socioeconomic and health disparities in these populations. Future studies into stroke incidence in Indigenous populations should be designed and conducted with Indigenous oversight and governance to facilitate improved outcomes and capacity building.
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| 6. |
- Barber, Megan R.W., et al.
(author)
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Economic Evaluation of Damage Accrual in an International Systemic Lupus Erythematosus Inception Cohort Using a Multistate Model Approach
- 2020
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In: Arthritis Care and Research. - : Wiley. - 2151-464X .- 2151-4658. ; 72:12, s. 1800-1808
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Journal article (peer-reviewed)abstract
- Objective: There is a paucity of data regarding health care costs associated with damage accrual in systemic lupus erythematosus. The present study was undertaken to describe costs associated with damage states across the disease course using multistate modeling. Methods: Patients from 33 centers in 11 countries were enrolled in the Systemic Lupus International Collaborating Clinics (SLICC) inception cohort within 15 months of diagnosis. Annual data on demographics, disease activity, damage (SLICC/American College of Rheumatology Damage Index [SDI]), hospitalizations, medications, dialysis, and selected procedures were collected. Ten-year cumulative costs (Canadian dollars) were estimated by multiplying annual costs associated with each SDI state by the expected state duration using a multistate model. Results: A total of 1,687 patients participated; 88.7% were female, 49.0% were white, mean ± SD age at diagnosis was 34.6 ± 13.3 years, and mean time to follow-up was 8.9 years (range 0.6–18.5 years). Mean annual costs were higher for those with higher SDI scores as follows: $22,006 (Canadian) (95% confidence interval [95% CI] $16,662, $27,350) for SDI scores ≥5 versus $1,833 (95% CI $1,134, $2,532) for SDI scores of 0. Similarly, 10-year cumulative costs were higher for those with higher SDI scores at the beginning of the 10-year interval as follows: $189,073 (Canadian) (95% CI $142,318, $235,827) for SDI scores ≥5 versus $21,713 (95% CI $13,639, $29,788) for SDI scores of 0. Conclusion: Patients with the highest SDI scores incur 10-year cumulative costs that are ~9-fold higher than those with the lowest SDI scores. By estimating the damage trajectory and incorporating annual costs, data on damage can be used to estimate future costs, which is critical knowledge for evaluating the cost-effectiveness of novel therapies.
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| 7. |
- Barber, Megan R.W., et al.
(author)
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Remission and low disease activity are associated with lower healthcare costs : results from the Systemic Lupus International Collaborating Clinics (SLICC) inception cohort
- 2024
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In: Annals of the Rheumatic Diseases. - 0003-4967.
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Journal article (peer-reviewed)abstract
- Objectives: This study aims to determine the independent impact of definitions of remission/low disease activity (LDA) on direct/indirect costs (DCs, ICs) in a multicentre inception cohort. Methods: Patients from 31 centres in 10 countries were enrolled within 15 months of diagnosis and assessed annually. Five mutually exclusive disease activity states (DAS) were defined as (1) remission off-treatment: clinical (c) SLEDAI-2K=0, without prednisone/immunosuppressants; (2) remission on-treatment: cSLEDAI-2K=0, prednisone ≤5 mg/day and/or maintenance immunosuppressants; (3) LDA-Toronto Cohort (TC): cSLEDAI-2K≤2, without prednisone/immunosuppressants; (4) modified lupus LDA state (mLLDAS): SLEDAI-2K≤4, no activity in major organs/systems, no new activity, prednisone ≤7.5 mg/day and/or maintenance immunosuppressants and (5) active: all remaining assessments. At each assessment, patients were stratified into the most stringent DAS fulfilled and the proportion of time in a DAS since cohort entry was determined. Annual DCs/ICs (2021 Canadian dollars) were based on healthcare use and lost workforce/non-workforce productivity over the preceding year. The association between the proportion of time in a DAS and annual DC/IC was examined through multivariable random-effects linear regressions. Results: 1692 patients were followed a mean of 9.7 years; 49.0% of assessments were active. Remission/LDA (per 25% increase in time in a remission/LDA state vs active) were associated with lower annual DC/IC: remission off-treatment (DC -$C1372; IC -$C2507), remission on-treatment (DC -$C973; IC -$C2604,) LDA-TC (DC -$C1158) and mLLDAS (DC -$C1040). There were no cost differences between remission/LDA states. Conclusions: Our data suggest that systemic lupus erythematosus patients who achieve remission, both off and on-therapy, and reductions in disease activity incur lower costs than those experiencing persistent disease activity.
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| 8. |
- Lederman, Judith S., et al.
(author)
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Completing the progression establishing an international baseline of primary, middle and secondary students’ views of scientific inquiry
- 2023
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In: International Journal of Science Education. - : Routledge. - 0950-0693 .- 1464-5289.
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Journal article (peer-reviewed)abstract
- Knowledge of scientific inquiry (SI) is considered essential to the development of an individual's Scientific Literacy (SL) and therefore, SI is included in many international science education reform documents. Two previous large scale international studies assessed the SI understandings of students entering middle school and secondary students at the end of their formal K-12 science education. The purpose of this international project was to use the VASI-E to collect data on what primary level students have learned about SI in their first few years of school. This study adds to previous research to bridge the landscape of SI understandings now with representation from primary, middle and high school samples. A total of 4,238 students from 35 countries/regions spanning six continents participated in the study. The results show that globally, primary students are not adequately informed about SI for their age group. However, when compared with the students in the previous international studies (grades seven and 12), the primary students' understandings were surprisingly closer to the levels of understanding of SI of the secondary school students than those in the seventh grade study.
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| 9. |
- Viljur, Mari-Liis, et al.
(author)
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The effect of natural disturbances on forest biodiversity : an ecological synthesis
- 2022
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In: Biological Reviews. - : Wiley. - 1464-7931 .- 1469-185X. ; 97:5, s. 1930-1947
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Journal article (peer-reviewed)abstract
- Disturbances alter biodiversity via their specific characteristics, including severity and extent in the landscape, which act at different temporal and spatial scales. Biodiversity response to disturbance also depends on the community characteristics and habitat requirements of species. Untangling the mechanistic interplay of these factors has guided disturbance ecology for decades, generating mixed scientific evidence of biodiversity responses to disturbance. Understanding the impact of natural disturbances on biodiversity is increasingly important due to human-induced changes in natural disturbance regimes. In many areas, major natural forest disturbances, such as wildfires, windstorms, and insect outbreaks, are becoming more frequent, intense, severe, and widespread due to climate change and land-use change. Conversely, the suppression of natural disturbances threatens disturbance-dependent biota. Using a meta-analytic approach, we analysed a global data set (with most sampling concentrated in temperate and boreal secondary forests) of species assemblages of 26 taxonomic groups, including plants, animals, and fungi collected from forests affected by wildfires, windstorms, and insect outbreaks. The overall effect of natural disturbances on α-diversity did not differ significantly from zero, but some taxonomic groups responded positively to disturbance, while others tended to respond negatively. Disturbance was beneficial for taxonomic groups preferring conditions associated with open canopies (e.g. hymenopterans and hoverflies), whereas ground-dwelling groups and/or groups typically associated with shady conditions (e.g. epigeic lichens and mycorrhizal fungi) were more likely to be negatively impacted by disturbance. Across all taxonomic groups, the highest α-diversity in disturbed forest patches occurred under moderate disturbance severity, i.e. with approximately 55% of trees killed by disturbance. We further extended our meta-analysis by applying a unified diversity concept based on Hill numbers to estimate α-diversity changes in different taxonomic groups across a gradient of disturbance severity measured at the stand scale and incorporating other disturbance features. We found that disturbance severity negatively affected diversity for Hill number q = 0 but not for q = 1 and q = 2, indicating that diversity–disturbance relationships are shaped by species relative abundances. Our synthesis of α-diversity was extended by a synthesis of disturbance-induced change in species assemblages, and revealed that disturbance changes the β-diversity of multiple taxonomic groups, including some groups that were not affected at the α-diversity level (birds and woody plants). Finally, we used mixed rarefaction/extrapolation to estimate biodiversity change as a function of the proportion of forests that were disturbed, i.e. the disturbance extent measured at the landscape scale. The comparison of intact and naturally disturbed forests revealed that both types of forests provide habitat for unique species assemblages, whereas species diversity in the mixture of disturbed and undisturbed forests peaked at intermediate values of disturbance extent in the simulated landscape. Hence, the relationship between α-diversity and disturbance severity in disturbed forest stands was strikingly similar to the relationship between species richness and disturbance extent in a landscape consisting of both disturbed and undisturbed forest habitats. This result suggests that both moderate disturbance severity and moderate disturbance extent support the highest levels of biodiversity in contemporary forest landscapes.
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| 10. |
- Wynberg, Elke, et al.
(author)
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Variability in white blood cell count during uncomplicated malaria and implications for parasite density estimation : a WorldWide Antimalarial Resistance Network individual patient data meta-analysis
- 2023
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In: Malaria Journal. - : Springer Nature. - 1475-2875. ; 22
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Journal article (peer-reviewed)abstract
- Background: The World Health Organization (WHO) recommends that when peripheral malarial parasitaemia is quantified by thick film microscopy, an actual white blood cell (WBC) count from a concurrently collected blood sample is used in calculations. However, in resource-limited settings an assumed WBC count is often used instead. The aim of this study was to describe the variability in WBC count during acute uncomplicated malaria, and estimate the impact of using an assumed value of WBC on estimates of parasite density and clearance.Methods: Uncomplicated malaria drug efficacy studies that measured WBC count were selected from the WorldWide Antimalarial Resistance Network data repository for an individual patient data meta-analysis of WBC counts. Regression models with random intercepts for study-site were used to assess WBC count variability at presentation and during follow-up. Inflation factors for parasitaemia density, and clearance estimates were calculated for methods using assumed WBC counts (8000 cells/mu L and age-stratified values) using estimates derived from the measured WBC value as reference.Results: Eighty-four studies enrolling 27,656 patients with clinically uncomplicated malaria were included. Geometric mean WBC counts (x 1000 cells/mu L) in age groups < 1, 1-4, 5-14 and >= 15 years were 10.5, 8.3, 7.1, 5.7 and 7.5, 7.0, 6.5, 6.0 for individuals with falciparum (n = 24,978) and vivax (n = 2678) malaria, respectively. At presentation, higher WBC counts were seen among patients with higher parasitaemia, severe anaemia and, for individuals with vivax malaria, in regions with shorter regional relapse periodicity. Among falciparum malaria patients, using an assumed WBC count of 8000 cells/mu L resulted in parasite density underestimation by a median (IQR) of 26% (4-41%) in infants < 1 year old but an overestimation by 50% (16-91%) in adults aged = 15 years. Use of age-stratified assumed WBC values removed systematic bias but did not improve precision of parasitaemia estimation. Imprecision of parasite clearance estimates was only affected by the within-patient WBC variability over time, and remained < 10% for 79% of patients.Conclusions: Using an assumed WBC value for parasite density estimation from a thick smear may lead to underdiagnosis of hyperparasitaemia and could adversely affect clinical management; but does not result in clinically consequential inaccuracies in the estimation of the prevalence of prolonged parasite clearance and artemisinin resistance.
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