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Regional stream temperature modeling in pristine Atlantic salmon rivers: A hybrid deterministic–Machine Learning approach.
Get PDFStudy region
Pristine Atlantic salmon rivers located across northeastern Canada and the U.S.
Study focus
To simulate water temperature in ungauged rivers, we explore the regionalization of thermal parameters within the CEQUEAU model—a deterministic, semi-distributed hydrological and water temperature model. Additionally, a global sensitivity analysis is conducted to identify the most sensitive thermal parameters within the study region. We employed the support vector regression algorithm (SVR), to map the dependence of these parameters with climatic and watershed characteristics.
New hydrological insights for the region
Parameters controlling radiative and sensible heat fluxes are the most critical for CEQUEAU water temperature modeling within the study region. Key explanatory variables include low cloud coverage, high wind speed quantiles, upstream land cover areal coverage, distance to the coast, watershed orientation, and topographical features describing surface curvature and elevation. The machine learning-based regionalization approach provides a robust approach for deriving water temperature model parameters from watershed attributes, provided flow measurements are available. Using leave-one-out cross-validation, support vector regression (SVR) significantly outperformed the traditionally used multiple linear regression (MLR), achieving a mean regional RMSE of 1.89 °C
Selective leaching of rare earths, base metals and precious metals from used smartphones.
No full textDiscarded smartphones represent a valuable source of rare earths (REE), base metals and precious metals. This study focussed on the optimisation of three-stage selective leaching conditions for REE, copper and precious metals (Au and Ag), respectively, contained in printed circuit boards (PCBs) found in end-of-life smartphones. The effects of several leaching conditions, such as sulphuric acid and thiourea concentrations, were investigated using a statistical approach based on a design of experiments using Box–Behnken methodology. Optimum leaching efficiencies were achieved when PCB powder was contacted (solid concentration of 100 g/L) with (1) a 0.2 M H2SO4 solution for 30 min at a temperature of 20°C for REEs; (2) a 1 M H2SO4 solution with 67 g H2O2/L for 180 min at 80°C for Cu and (3) a solution of 42 g thiourea/L in 0.1 M H2SO4 and 9 g Fe2(SO4)3/L for 120 min at 20°C for Au and Ag. Using these optimal conditions, a complete leaching procedure included an REE solubilisation step and a base metal leaching step, both repeated twice, and a precious metal leaching step. This procedure solubilised 91% of the REE, 100% of the copper, 98% of the gold and 87% of the silver contained in the PCB powder during their respective leaching stages
A type 1 immune-stromal cell network mediates disease tolerance against intestinal infection
No full textType 1 immunity mediates host defense through pathogen elimination, but whether this pathway also impacts tissue function is unknown. Here, we demonstrate that rapid induction of interferon γ (IFNγ) signaling coordinates a multicellular response that is critical to limit tissue damage and maintain gut motility following infection of mice with a tissue-invasive helminth. IFNγ production is initiated by antigen-independent activation of lamina propria CD8(+) T cells following MyD88-dependent recognition of the microbiota during helminth-induced barrier invasion. IFNγ acted directly on intestinal stromal cells to recruit neutrophils that limited parasite-induced tissue injury. IFNγ sensing also limited the expansion of smooth muscle actin-expressing cells to prevent pathological gut dysmotility. Importantly, this tissue-protective response did not impact parasite burden, indicating that IFNγ supports a disease tolerance defense strategy. Our results have important implications for managing the pathophysiological sequelae of post-infectious gut dysfunction and chronic inflammatory diseases associated with stromal remodeling.</br
The amount of soil used for DNA extractions has a minimal effect on characterization of microbial communities in a temperate agricultural region
No full textThe ability to analyze soil microbial communities continues to improve with methodological advancements. The amount of soil used for DNA extractions to characterize the microbial community has been suggested to alter results. However previous efforts to quantify this variation have not always utilized consistent methodology, making it difficult to assess when and how the amount of soil impacts the results. In this study, we pooled technical replicates of DNA extractions using a standardized protocol with the most commonly used kit (i.e., 0.25 g starting soil weight with the Qiagen PowerSoil Pro kit) into five treatments: 0.25 g, 0.5 g, 1.0 g, 2.0 g, and 4.0 g to characterize the soil microbial communities from four distinct land use systems (grazed pasture, conventional forage, woodlot, and blueberry). Following DNA extraction, we assessed total DNA yield, fungal and bacterial abundance (qPCR), and alpha and beta diversity (amplicon sequencing) of the soil microbial community to determine the effect of soil weight on these metrics. Soil weight did not have a significant effect on any of these metrics. Land use system had a significant effect on all metrics except for prokaryotic Shannon diversity. The land use systems and the spatial organization within each system (i.e., field replicates) were easily distinguishable regardless of the amount of soil used to assess the samples. These results confirm the suitability of 0.25 g soil to accurately (and affordably) assess soil microbial communities in temperate agricultural soils, and accentuate the importance of methodological consistency within a study. </br
Unveiling Inequalities in the gig Economy: Analyzing driver earnings in Toronto’s ridehailing industry
No full textThis study examines the net earnings of transportation network company (TNC) drivers in Toronto, using a comprehensive dataset of 84 million TNC trips conducted between January 2023 and April 2024. By integrating trip data with vehicle-specific information, the analysis offers a comprehensive view of driver earnings both before and after expenses. Findings reveal that in 2023, median gross earnings per engaged hour were 15.31 after deducting expenses, leaving 57% of drivers earning less than the provincial minimum wage of 7.94 per in-app hour in 2023 and $5.97 in 2024, resulting in over 95% of drivers earning below minimum wage. These findings highlight systemic issues in the TNC industry, including prolonged unpaid waiting periods for ride assignments and significant variability in operating costs. We explore policy solutions such as utilization rate targets and minimum pay standards, alongside improvements to the data collection process, to better ensure fair wages for TNC drivers. By uncovering the prevailing wage conditions in the TNC industry, this research underscores the urgent need for proactive regulatory measures to enhance working conditions for TNC drivers in Toronto
Acceptability and safety of a probiotic beverage supplementation (Bio-K +) and feasibility of the proposed protocol in children with a diagnosis of autism spectrum disorder
Get PDFBackground: Autism spectrum disorder (ASD) is a group of neurodevelopmental disorders defined by stereotyped behavior and challenges in social communication and social interaction. ASD is associated with various comorbidities, including anxiety, gastrointestinal (GI) symptoms and sleep disorders. Evidence supports an association between intestinal dysbiosis and the severity of ASD-related symptoms. Probiotic intake was suggested to restore microbial homeostasis and decrease neurobehavioral, GI and sleep symptoms in individuals diagnosed with autism. Methods: This study aims to evaluate the acceptability and safety of a Bio-K + probiotics beverage in autistic children aged 4 to 11 years and the feasibility of the proposed research protocol to measure its impact on behaviors and comorbidities. The 30-week study consisted of daily supplementation with Bio-K + probiotics for 14 weeks. Acceptability and safety were monitored throughout the study. Feasibility was assessed by comparing recruitment and completion rates to pre-established thresholds. Preliminary impact of supplementation on behaviors (Autism Treatment Evaluation Checklist (ATEC) score), GI symptoms and sleep disorders was evaluated. Results: Of the 23 children recruited (mean age 6.7 ± 2.2 years, 70% males), 65% had GI problems and 91% had sleep disorders. Probiotic supplementation was accepted by all participants and no product-related adverse event was reported. Feasibility rates exceeded pre-established thresholds for almost all study outcomes including recruitment rate, compliance, electroencephalography, actigraphy and completion of questionnaires. Preliminary data suggest an improvement in behaviors associated with autism assessed with the total ATEC score, and in GI symptoms and sleep disorders. Conclusion: This study demonstrates probiotic beverage acceptability and safety and protocol feasibility in autistic children. To further support our data, a double-blinded placebo-controlled study is needed to determine its efficacy
Phenotypic plasticity in cell elongation among closely related bacterial species
Get PDFCell elongation in bacteria has been studied over many decades, in part because its underlying mechanisms are targets of numerous antibiotics. While multiple elongation modes have been described, little is known about how these strategies vary across species and in response to evolutionary and environmental influences. Here, we use fluorescent D-amino acids to track the spatiotemporal dynamics of bacterial cell elongation, revealing unsuspected diversity of elongation modes among closely related species of the family Caulobacteraceae. We identify species-specific combinations of dispersed, midcell and polar elongation that can be either unidirectional or bidirectional. Using genetic, cell biology, and phylogenetic approaches, we demonstrate that evolution of unidirectional-midcell elongation is accompanied by changes in the localization of the peptidoglycan synthase PBP2. Our findings reveal high phenotypic plasticity in elongation mechanisms, with implications for our understanding of bacterial growth and evolution. </br
Milestones in the development of Myxococcus xanthus as a model multicellular bacterium
No full textFrom the humblest of beginnings (i.e. a pile of dry cow dung) over 80 years ago, the Gram-negative bacterium Myxococcus xanthus has emerged as a premier model system for studying diverse fields of bacteriology, including multicellular development, sporulation, motility, cell-envelope biogenesis, spatiotemporal regulation, signaling, photoreception, kin recognition, social evolution, and predation. As the flagship representative of myxobacteria found in varied terrestrial and aquatic environments, M. xanthus research has evolved into a collaborative global effort, as reflected by the contributions to this article. In celebration of the upcoming 50th anniversary of the International Conference on the Biology of Myxobacteria, this review highlights the historical and ongoing contributions of M. xanthus as a multifaceted model bacterium.</br
Potential mode of action of multispecies inoculums on wheat growth under water stress
Get PDFManipulating microbial communities could increase crop resistance to environmental stressors such as drought. It is, however, not clear what would be the best approach to do so and what microbial traits are important. Here, we first compare multispecies inoculums created using different approaches. The only inoculum that increased wheat fresh biomass under drought was the one created from 25 isolates that had showed a capacity to grow under high osmolarity. We then looked at two potential mechanisms of action of this inoculum: (i) direct action, by sequencing and screening the genomes of the inoculated bacteria, (ii) indirect action, by sequencing the 16S ribosomal ribonucleic acid gene and internal transcribed spacer region of rhizosphere, root, and leaves microbial communities. The microbes in the inoculum harbored many traits related to plant growth promotion, competition, and water stress resistance. The inoculation also resulted in significant shifts in the microbial communities associated with wheat, including some microorganisms (e.g. Rhizobium, Shinella, and Klebsiella) previously reported to improve plant drought resistance. We conclude that the inoculum studied here increased wheat growth because it potentially acted on two fronts: directly, through the traits it was selected for, and indirectly, through inducing shifts in the resident plant microbial communities.</br
Assessing the potential for Atlantic salmon (<i>Salmo salar</i>) colonization of Nunavik’s Arctic and subarctic rivers by 2070–2100.
Get PDFIn Nunavik, Québec, Canada, Atlantic salmon (Salmo salar) populations reach their northern limit in four rivers of southern Ungava Bay. With projected river warming from climate change, this study assesses the potential for Atlantic salmon to colonize new rivers in Nunavik by modelling water temperatures and evaluating river accessibility. Migration barriers were identified with a literature review, topographic data, and satellite imagery. Water temperatures were modelled with a generalized additive model using ERA5-Land air temperature, observed daily mean temperatures, and water surface temperature estimated from Landsat imagery. Our projections indicate an average increase of the rivers mean summer temperatures of 1.2–2.7 °C by the end of the century, enhancing thermal conditions in current salmon rivers with more days with optimal growth temperatures (16–20 °C) while still having limited days with thermal stress (>22 °C). By 2100, other Ungava Bay rivers may be colonized, as most are accessible and expected to reach more suitable temperatures. However, Nunavik’s northernmost rivers would remain too cold and colonization of the Hudson Bay watershed appears less likely due to the inaccessibility of most rivers and their distance from established anadromous populations