Université du Québec à Montréal

Wildfires are an increasingly important factor in boreal forest biome. The fire cycle have significant effects on the cycling of nutrients within and through an ecosystem. Past research shows that major elements, nutrients, and organic matter in stream water can be altered for decades after a wildfire. Here we examine how stream chemistry might be used to characterize biogeochemical effects of fire across the continuous permafrost taiga of the Central Siberia. By comparing the results of laboratory combustion of organic horizons, soil solution chemistry in burned and unburned watersheds, and stream chemistry in a chronosequence of watersheds with a well-described fire history, we assess possible proxies in stream water chemistry for wildfire severity and timing in this landscape. Our results suggest that the time since last wildfire can be estimated by sulfates (SO 4 2− ) and nitrates (NO 3 − ) concentrations, and that the soil active layer thickness (ALT, the soil depth at which soil thaws annually) increase by wildfires is reflected in bicarbonates (HCO 3 − ) concentrations. Phosphate (PO 4 3− ), although it is released from organic matter by combustion, is unchanged in stream water following fire. Chloride (Cl − ) produces a useful marker for hydrologic conditions at the time of sampling, allowing a relatively small number of stream water samples to be used to characterize past fire regime. Concentrations of SO 4 2− , NO 3 − and HCO 3 − in stream runoff can thus be used as a specific fingerprint of fire history in the northern taiga larch and birch forests of the Central Siberia, since an increase in their concentrations in stream runoff reflects fire occurrence in the catchment area. • Wildfires increase concentrations of major ions in pyrogenic organic layers, topsoil and streams. • Phosphorus is liberated by organic matter combustion, but retained in subsoil. • Wildfires affect stream HCO 3 − , SO 4 2− , Cl − and NO 3 − concentrations at decadal scales. • Stream bicarbonate can serve as a proxy for the active layer depth and wildfire timing • Sulfate in stream water is the most reliable indicator of time since fire disturbance in the catchments.

Since 2020, and heightened during the COVID-19 pandemic, there has been a spike in reports of hate-motivated activity within universities across Canada. However, the experiences of hate by university students continue to remain under-researched and underdeveloped in Canada. This article presents findings from a Canada-wide survey conducted on the experiences Canadian university students have with hate-motivated activity within in-person and online campus spaces. The focus of this study was to provide an understanding of Canadian university students' experiences with hate, both online and offline, its consequences and possible solutions. By learning about student experiences, we document the varying types of hate students experience on campus, its physical, emotional, and mental impacts, the services and support that exist, and how universities understand and respond to hate. The main conclusions of our study are 1. Most of the students experience hate more than once, more repeatedly online and in multiple university spaces, than they do in-person 2. There are higher instances of students who report experiencing hate based on their ethnicity and attributed race/skin colour, physical appearance, and religion. 3. Hate incidents affect students’ mental health, academic growth, and sense of safety. 4. Students agree that their university can do more to prevent hate, both online and offline. With this data, we aim to increase awareness of the different degrees of hate on university campuses and help improve universities' anti-hate and anti-racism frameworks. • Students experience hate both online and offline in Canadian universities. • Hate is experienced most often based on ethnicity, race, skin colour, and religion. • Experiencing hate impacts students’ mental health, academic growth, and safety. • Students call for stronger prevention and support systems to address gaps. • Article offers policy recommendations to improve anti-hate frameworks.

When compared to their aryl-substituted counterparts, the chemistry of alkyl bismuth cations is still in its infancy. In order to tackle this synthetic challenge and close this gap of knowledge, we have developed protocols for the synthesis of precursors with unusual bismacyclic motifs and cyclopropyl ligands, Bi(CH2)5Br and BicPr2Cl. These and the more common precursor BiiPr2Cl could be turned into the cationic species [BiR2(SbF6)] (R2=(CH2)5, cPr2, iPr2), the first examples of alkyl bismuth cations with longer alkyl chains and cyclic motifs. The ability of these compounds to act as soft Z-type ligands is demonstrated by the formation of metal-only Lewis pairs in reactions with the platinum(0) precursor [Pt(PCy3)2]. The products of these reactions [(PCy3)2Pt→BiR2(SbF6)] show unsupported Pt→Bi bonds, and could be isolated and fully characterized. Pt oxidation and ring-opening of the cyclopropyl ligand were uncovered as a decomposition pathway.

This study aimed to determine whether sex-related differences exist in resting-state quantitative electroencephalography (rs-QEEG), along with post-concussion symptoms and psychological health indicators, at baseline and within 72h following a sport-related concussion. Baseline visit included 115 (31 women) student-athletes aged 16-22years old where self-reported measures of psychological health and post-concussion symptoms, as well as 10min of rs-QEEG (five minutes eyes-closed, five minutes eyes-open) were recorded. 30 athletes (8 women) subsequently sustained a sport-related concussion during training or competition of the 2019-2020 season and were reassessed with the same post-concussion symptoms scale and 10min of rs-QEEG. Primary rs-QEEG outcomes included absolute and relative power across standard frequency bands. At baseline, women exhibited higher beta1 power (absolute and relative) and higher beta2 power (absolute), primarily in the eyes-open condition, after Benjamini-Hochberg corrections were applied. They also reported greater scores for anxiety, sleep-arousal, affective and total symptoms. No significant associations between rs-QEEG power and symptoms were observed after adjustment for multiple comparisons. Following a concussion, no statistically significant main effect of time on rs-QEEG measures was observed after correction for multiple comparisons. However, theta absolute power showed a decrease across regions in the eyes-open condition at the unadjusted level. Additionally, women continued to show higher beta2 power (absolute and relative) than men. An association between alpha absolute power and affective symptoms was observed in women at the post-concussion assessment but did not remain significant in sensitivity analyses. Overall, these findings indicate sex-related differences across rs-QEEG parameters and symptom profiles, both before and after a concussion. Although the clinical utility of rs-QEEG has not yet been established, our findings underscore the importance of considering biological sex when interpreting rs-QEEG metrics and evaluating post-concussion symptomatology.

Urban vegetation varies with socio-economic gradients, as lower-income neighborhoods often host sparser and less diverse green spaces. This disparity may affect respiratory health by influencing exposure to bioaerosols. Understanding the characteristics of this aerobiome could help anticipate risks related to allergies and other respiratory conditions. Here, we hypothesized that urban vegetation cover and socio-economic status shape urban bioaerosol dynamics. We sampled bioaerosols at 65 sites across three Canadian cities of varying population size and density using an active air sampler over four months, and characterized their bacterial, fungal, and plant particles composition using amplicon sequencing. Seasonal alpha diversity varied significantly for fungi and plant particles. Based on beta diversity, sampling period alone explained up to 40% of plant particle, 29% of fungal, and 11% of bacterial bioaerosol composition variation. In contrast, vegetation cover explained only a minor portion of the variance in bioaerosol composition, and median household income, almost none. These findings provide a critical baseline for understanding the urban aerobiome and highlight the need to study how vegetation identity and diversity, rather than cover alone, may shape bioaerosol dynamics in cities. As cities grow and urban greening initiatives expand, demystifying the aerobiome dynamics becomes an urgent public health priority.