Université du Québec en Abitibi-Témiscamingue
Recent publications
The satellite microwave emissivity difference vegetation index (EDVI) has been used in previous studies to estimate FCs and FRP using traditional multivariate linear regression models. However, the nonlinear effects and contributions of numerous factors that affect forest fires cannot be disentangled by this model. Using the random forest (RF) model, this study utilized multiple EDVIs and the optical normalized difference vegetation index (NDVI) as key fuel properties to resolve the physical driving mechanisms of forest fires and to estimate the daily FCs and FRP over East Asia. The results showed that the estimated FCs and FRP were in good agreement with satellite observations, with a spatial R of 0.59 for FCs and 0.63 for FRP and a temporal R of 0.80 for FCs and 0.81 for FRP. The integration of EDVIs and NDVI into the RF model was found to improve model performance and generate overall lower systematic errors than the model without vegetation variables. Model performance was better than that in previous studies using multivariate linear regression models. In addition, EDVIs showed greater importance than NDVI. This was largely due to their daily temporal resolution that allowed EDVIs to capture forest fire dynamics in time. The combination of the RF model with satellite microwave and optical observations shows good performance and has great potential for FC and FRP estimations in global fire danger assessment.
In an effort to offset the marginalization of Indigenous women’s knowledge, we used a qualitative participatory approach to co-construct the meaning of the pregnancy and birthing knowledge of Innu (Indigenous people in Quebec, Canada) and Atikamekw (Indigenous people in Quebec, Canada) women in terms of connection to the land. Through thematic analysis of interviews, we show that the women have maintained a deep connection to the land, even though they may not be practicing land birth anymore due to restrictions imposed by governments and the medical profession. Despite the invisibilization of their connection to the land, Innu and Atikamekw women still perceive it as essential to the expression of their identity and the well-being of their communities. They emphasized the importance of rematriation, which is restoring sacred matrilineal relationships between people and land, as a way to restore their roles and leadership within their communities.
Prediction of neutral mine drainage (NMD) chemistry is difficult with the predictive tools developed for acid mine drainage (AMD). To address this problem, a methodology to assess NMD risk was developed using Lac Tio Mine waste rock as a positive control. The methodology compares the maximum potential for contaminant release (in this case, nickel) using the waste rock’s total metal content and the sorption capacity of the material (q max ) combined with a mineralogical assessment and modified kinetic leaching experiments that use a chelating agent to prevent immobilization processes from occurring. The results indicate that the potential NMD risk associated with Lac Tio waste rock would be assessed as probable with the proposed methodology. Indeed, the total nickel concentrations in the Lac Tio waste rock range from 270 to 590 mg/kg. The nickel is found in Ni-rich pyrites, which proved to effectively leach when no immobilization occurred (using ethylenediaminetetraacetic acid, or EDTA, leaching). The material’s sorption capacities were between 127 and 197 mg/kg of Ni. The sorption capacity to total Ni content ratio of the material was < 1, indicating that the material has fewer sorption sites for Ni than Ni contained within the material, thereby underscoring the potential risk of Ni leaching over time. The approach proposed in this work provides an additional tool for the assessment water quality risk associated with NMD.
Context The vegetation composition of northeastern North American forests has significantly changed since pre-settlement times, with a marked reduction in conifer-dominated stands, taxonomic and functional diversity. These changes have been attributed to fire regime shifts, logging, and climate change. Methods In this study, we disentangled the individual effects of these drivers on the forest composition in southwestern Quebec from 1830 to 2000 by conducting retrospective modelling using the LANDIS-II forest landscape model. The model was run based on pre-settlement forest composition and fire history reconstructions, historical timber harvest records, and climate reanalysis data. We compared counterfactual scenarios excluding individual factors to a baseline historical scenario. Results and Conclusions Our results indicated that timber harvesting had the greatest impact on forest dynamics over the past centuries. In the absence of timber harvesting, pre-settlement species abundances were largely maintained, preserving key functional traits like fire and shade tolerance that contribute to ecosystem resilience. Increased fire activity during the settlement period contributed to the increase of early-successional aspen (Populus tremuloides), but timber harvesting played the dominant role. Fire exclusion had no influence on vegetation composition, suggesting mesophication unfolds over longer timescales than those captured in this study. Climate change, characterized by modest increases in temperature and precipitation, had a minor effect on vegetation shifts, as increased precipitation might have mitigated the adverse effects of rising temperatures. However, future climate change is projected to become a more significant driver of forest composition. These findings underscore the importance of forest restoration and continued research on past forest dynamics to better understand current and future changes.
Background The risks associated with medications and co-medications for chronic pain (CP) can influence a physician’s choice of drugs and dosages, as well as a patient’s adherence to the medication. High-quality care requires patients to participate in medication decisions. This study aimed to compare perceived risks of medications and co-medications between physicians and persons living with CP. Methods This cross-sectional survey conducted in Quebec, Canada, included 83 physicians (snowball sampling) and 141 persons living with CP (convenience sampling). Perceived risks of adverse drug reaction of pain medications and co-medications were assessed using 0–10 numerical scales (0 = no risk, 10 = very high risk). An arbitrary cutoff point of 2-points was used to ease the interpretation of our data. Physicians scored the 36 medication subclasses of the Medication Quantification Scale 4.0 (MQS 4.0) through an online survey, while CP patients scored the medication subclasses they had taken in the last three months through telephone interviews. Results Persons living with CP consistently perceived lower risks of adverse drug reaction compared to physicians. For eight subclasses, the difference in the mean perceived risk score was > 2 points and statistically significant (p < 0.05): non-specific oral NSAIDs, acetaminophen in combination with an opioid, short-acting opioids, long-acting opioids, tricyclic antidepressants, antipsychotics, benzodiazepines, and medical cannabis. Conclusions Divergent risk perceptions between physicians and patients underscore the necessity of facilitating a more extensive discussion on medications and co-medications risks to empower patients to make informed decisions and participate in shared decision-making regarding their treatments.
Wood formation is the Rosetta stone of tree physiology: a traceable, integrated record of physiological and morphological status. It also produces a large and persistent annual sink for terrestrial carbon, motivating predictive understanding. Xylogenesis studies have greatly expanded our knowledge of the intra‐annual controls on wood formation, while dendroecology has quantified the environmental drivers of multi‐annual variability. But these fields operate on different timescales, making it challenging to predict how short (e.g. turgor) and long timescale processes (e.g. disturbance) interactively influence wood formation. Toward this challenge, wood growth responses to natural climate events provide useful but incomplete explanations of tree growth variability. By contrast, direct manipulations of the tree vascular system have yielded unexpected insights, particularly outside of model species like boreal conifers, but they remain underutilized. To improve prediction of global wood formation, we argue for a new generation of experimental manipulations of wood growth across seasons, species, and ecosystems. Such manipulations should expand inference to diverse forests and capture inter‐ and intra‐specific differences in wood growth. We summarize the endogenous and exogenous factors influencing wood formation to guide future experimental design and hypotheses. We highlight key opportunities for manipulative studies integrating measurements from xylogenesis, dendroanatomy, dendroecology, and ecophysiology.
Citizen science (CS) has gathered an impressive wealth of open biodiversity data over the last decade, with demonstrated significant scientific contributions in biology and conservation science. However, the contribution of CS in botanical research, and more particularly regarding inconspicuous taxonomic groups such as cryptogams remains largely unexplored. Here we assess the current status and contribution of CS in botanical research, with a special focus on non-vascular “cryptogams” (bryophytes, lichens, fungi, and algae). We conducted a literature review for the period 2012 to 2022 to synthesize the use of CS in botanical studies. We found an increasing trend in the use of CS for botanical research (average annual increase of ∼40%), although highly biased towards vascular plants (246 papers). Cryptogams remained strongly underrepresented (58 papers), although receiving slightly growing attention since 2018. The inconspicuousness nature, high diversity, challenges with species identification, and low public perception of cryptogams not only restrict the contribution made by non-experts but raise concerns about the reliability and robustness of generated data. This is fueled by the scarcity of foundational methodological studies in cryptogams, which seems to undermine the scientific confidence in engaging volunteers for their research or using open data from CS platforms and tools. Despite this, our review showed a gradual adoption of CS approaches for cryptogam research, which is particularly led by mycologists. We highlight the versatility and potential of CS approaches for advancing cryptogam knowledge across various research subjects at spatial and temporal scales otherwise unfathomable by researchers, and provide insights on the opportunities of application and possible solutions to the discussed limitations. We hope our work motivates mycologists, phycologists, bryologists, and lichenologists to further embrace CS, and increase public awareness on these highly sensitive and ecologically important taxa.
In the wood panel industry, metallic contaminants raise significant concerns, especially regarding the press plate's surface integrity, which requires a thorough inspection. This study investigated the effect of metallic contaminants on press plate damage and evaluated the use of infrared thermography (IRT) and infrared (IR) spectroscopy as non-destructive testing (NDT) methods for detecting these contaminants in wood panel manufacturing. Metallic contaminants embedded within lab-scale wood panels demonstrated their impact on the surface quality of both the press plate and the resulting panels. Moreover, confocal laser microscope analysis revealed that the surface roughness of the press plate surface was influenced by the specific alloy composition of contaminants, with steel and chromium contaminants exhibiting the more severe damage (e.g., mean roughness values of 59,80 and 84,64 μm, respectively). Thermography images exhibited the efficacy of IRT in detecting contaminants close to the surface of thin panels. However, an advanced camera is recommended for thicker panels and deeper contaminants to obtain a more accurate inspection. The Fourier-transform infrared spectroscopy (FTIR) evaluation revealed the presence of the metal-oxygen vibration band at approximately 668 cm ⁻¹ across all alloy compositions, suggesting its potential as a reliable reference for detecting metallic contaminants.
Background Climate change has devastating impacts on agriculture, increasing the yield gap for most crops, especially in developing nations. This is likely to worsen food insecurity in some countries, calling for efforts to close the yield gap as much as possible. Estimating the yield gap and its drivers is essential for devising strategies to increase yields. This study quantifies the wheat yield gap in Morocco's five major wheat production regions. It analyzes the historical sensitivity of wheat yield to temperature, precipitation, and soil moisture, which are important factors affecting agricultural productivity. Furthermore, it evaluates how these yield gaps impact the revenue of producers in these regions. This analysis was conducted using datasets, including the Global Dataset of Historical Yield (GDHY) for yield gap assessment, soil moisture data, ERA5 reanalysis data, and CHIRPS datasets for climate assessment from 1982 to 2016. Pearson correlation and multiple linear regression analyses were employed to reflect the variation characteristics of wheat yield and to identify the impacts of precipitation, temperature, and soil moisture on wheat yield. Results High regional differences in wheat yield gaps were observed, with values ranging from 1.64 t/ha in Casablanca Settat to 4.12 t/ha in Marrakech Safi, and temporal variability ranging from 9 to 18%. Wheat yields were found to be strongly correlated with rainfall, particularly from December to March. Temperature fluctuations had a significant negative impact on wheat yield across the regions. Soil moisture was positively correlated with wheat yields throughout all growing periods, showing the strongest impacts during the early vegetative development phase. Additionally, losses due to wheat yield gaps were considerable, ranging between $ 194 and 891 per hectare. The revenue loss due to Yield Gap I ranged from 49 to 71%, while the loss due to Yield Gap II ranged from 240 to 444%, depending on the method used to calculate the wheat yield gap. Conclusions Results reveal gaps in wheat yield, forming a basis for process-based modeling to understand crop yield gap drivers. Understanding yield gap drivers will play a pivotal role in evidence-based intervention strategies to enhance yields. By applying such strategies, it is possible to not only manage and reduce the variability in wheat production, but also ensure sustainable agricultural practices and achieve food security in Morocco and beyond.
This paper presents a detailed measurement and performance analysis of near-ground propagation channels in an underground mine for both Line-of-Sight (LOS) and Non-Line-of-Sight (NLOS) scenarios. The analysis is derived from channel measurements conducted at a frequency of 2.4 GHz with a bandwidth of 200 MHz, utilizing four different combinations of transmitter-receiver (Tx-Rx) antenna heights ranging from 10 cm to 120 cm. Key channel characteristics such as large-scale path loss, time dispersion, and coherence bandwidth are reported and evaluated. The study suggests that a multi-slope (four-slope) path loss model is more effective in predicting path loss across various propagation segments in the mining environment. The path loss coefficient (n) and shadowing variance (σ) show significant sensitivity to both the Tx-Rx distance and the heights of the Tx-Rx antennas, while the root mean square delay spread (τ rms) and coherence bandwidth (BC) are less affected by these variables. Moreover, distinct path loss patterns are observed for each combination of Tx-Rx antenna heights, resulting in varying signal attenuation levels. The identification of an optimal height for minimizing signal loss is thus required. These observations provide valuable and crucial insights into the near-ground propagation characteristics within the intricate and scattering-rich conditions of underground mines.
Monitoring the propagation of mechanical cardiac signals throughout the body is crucial for assessing cardiovascular health. A common drawback of current gold standard methods for vital sign monitoring is the necessity for continuous skin contact. Radar-based sensing offers a promising alternative by enabling contactless measurement of cardiac activity, including heart sound signals. As previous research has primarily focused on deriving signals from proximal body regions, insights into heart sound propagation to peripheral areas are lacking. To address this, we systematically investigated whether radar-based heart sound detection and propagation measurement is feasible across the whole body. We recorded heart sounds in N=22 participants sequentially at eleven locations using a custom-built continuous-wave radar system and phonocardiogram as heart sound gold standard. Additionally, an electrocardiogram was acquired as reference for overall heart activity. After synchronization and preprocessing, we manually segmented the heart sounds and extracted temporal characteristics from ensemble-averaged signals. Our findings show that heart sounds can be detected across the entire body with the radar-based as well as the gold standard system. Furthermore, the heart sounds' temporal characteristics vary between measurement locations. As the distance to the heart increases, we observed significantly increased propagation time intervals. This finding is consistent across both systems, exhibiting a strong agreement for the first heart sound ( r=0.73,p<0.001\mathbf {r = 0.73, p < 0.001} ) and a moderate agreement for the second heart sound ( r=0.56,p<0.001\mathbf {r = 0.56, p < 0.001} ). In conclusion, our work is the first to demonstrate that radar-based systems are feasible for contactless evaluation of heart sound propagation, offering new possibilities for research and health monitoring.
This paper tackles significant challenges in the design of millimeter-wave MIMO (Multi-input Multi-output) antennas for the Ka-band (26-30 GHz) as utilized in 5G applications. Current antenna designs suffer from limitations such as constrained bandwidth, inadequate gain, and restricted beam scanning capabilities, adversely affecting performance, particularly in high-density urban environments. A novel MIMO antenna featuring a 12-port dielectric lens has been proposed to address these issues, introducing several advancements to improve key performance metrics. The antenna demonstrates a peak realized gain of approximately 14 dBi and achieves a bandwidth exceeding 4 GHz. Importantly, it features full 360∘ beam scanning capabilities and maintains an exceptionally low envelope correlation coefficient (ECC) of less than 0.0014. The design also shows impressive radiation efficiency consistently exceeding 95%, complemented by excellent isolation characteristics with mutual coupling maintained below -30 dB. This research provides a scalable solution that could significantly enhance the performance of next-generation wireless networks, addressing the high demands of urban 5G deployments.
Satellite technologies are essential for global conservation actions through providing continuous, real-time Earth monitoring. However, development of these technologies necessitates an increase in rocket launches, which introduces new threats to biodiversity. Here, we mapped rocket launch sites and assessed their threats on protected areas and terrestrial biodiversity. Our analysis revealed that over 90% launch sites are within areas where unprotected habitats excesses 50% and over 62% of operating sites are located within or near protected areas. The threats from rocket launches are potentially associated with biomes, coordinates, and proximity to oceans. In particular, threatened terrestrial species in Tropical and Subtropical Moist Broadleaf Forests are more vulnerable to these risks compared to species in other biomes. Without strategic planning, the continued growth of rocket launches could create conflicts between technological development and conservation efforts, undermining the achievement of UN Biodiversity Goals.
In temperate and boreal ecosystems, trees undergo dormancy to avoid cold temperatures during the unfavorable season. This phase includes changes in frost hardiness, which is minimal during the growing season and reaches its maximum in winter. Quantifying frost hardiness is important to assess the frost risk and shifts of species distribution under a changing climate. We investigate the effect of local conditions and intra-specific variation on frost hardiness in sugar maple (Acer saccharum Marsh.). Seedlings belonging to seven provenances from the northern area of the species’ range were planted at two sites in Quebec, Canada. LT50, i.e., the lethal temperature for 50% of the cells, was measured monthly with the Relative Electrolyte Leakage (REL) method on branches and buds from September 2021 to July 2022. LT50 varied between −4 °C in summer (July) and − 68 °C in winter (February). Autumnal acclimation rates (September to early December) and mid-winter frost hardiness (December to early March) were similar in both sites. Samples in the southern site deacclimated faster than in the northern site between March and July, because of a warmer and earlier spring. No difference in frost hardiness was detected between provenances. Our results suggest that the frost hardiness trait is similar within the northern part of the sugar maple distribution, with local weather conditions having a greater influence than provenance. We demonstrate that LT50 in sugar maple can exceed −55 °C, far below the minimum temperatures occurring in winter at the northern limit of the species. In order to minimize the risk of damage from extreme frost events exceeding tree frost hardiness, a careful evaluation of site characteristics is more important than provenance selection. Other factors should also be considered within the context of changing climate, in particular the phenology of maple and avoidance of late frost in spring.
Phosphate mines produce large quantities of waste rock. These waste rocks are mixed and managed on the surface as large unrestored piles, which makes them difficult to rehabilitate. They primarily comprise carbonates, clays, marls, and cherts (flints). In many cases, the unrestored mine sites, when exposed to normal climatic conditions, could frequently produce toxic environmental pollution, and significant ecological disruptions. This research aims to assess the phosphate waste rock's (PWR) geochemistry and environmental behavior upstream of the extraction process. For this purpose, different core drilling specimens and data were collected from different lithologies and depths in the interlayers of the Benguerir mine to forecast the environmental profile and determine the mobility of the analyzed chemical species. These samples were analyzed for their petrographical, chemical, and mineralogical compositions, static leaching tests, and semi-dynamic test. The mineralogy results showed that the PWR mainly consists of calcite, dolomite, apatite, and quartz, with minor phases such as clay minerals. Chemically, the PWRs are dominated by the following major oxides: CaO and MgO, followed by SiO2 and P2O5. Trace elements can be classified into three groups based on their concentrations: group of Sr, Zn and Cr (> 150 ppm), group of Ba, V, Ni, Zr, Y, U, Cu, Cd, Co (10–150 ppm), and group of trace elements with relatively low concentrations (< 10 ppm): Rb, Pb, As, Mo, Se, Sc, Ga, Nb, Th, Hf, Sb and Cs. Environmentally, the pH of the leachates was neutral to alkaline (6 ± 0.6–9.3) for all the samples, which have a high neutralizing potential (38–991 kg CaCO3/t). The release of major and trace elements in the leaching test remains below international standard limits. Consequently, the leaching test results confirm the non-hazardous nature of the PWR. Therefore, the studied PWR could be considered a natural raw material and can be used in various applications in different sectors, such as civil engineering, cement industry, phosphate recovery, and acid mine drainage treatment through neutralization.
The fatigue test is an essential method used to evaluate the mechanical properties of materials and to assess their fatigue life under cyclic loads. Since the fatigue behavior of 3D-printed parts is highly dependent on fabrication process parameters, this study investigates the effect of infill density percentage and printing direction on fatigue life. Rotary bending fatigue tests were conducted on polylactide dog-bone specimens subjected to alternating peak stresses ranging from 35 to 70 MPa, printed in both horizontal and vertical orientations. The infill densities examined were 25, 50, 75, and 100%. The number of cycles to failure exhibited significant variability due to the 3D fabrication process itself. The S-N curves show that samples printed horizontally have higher strength than those printed vertically. Horizontal specimens generally exhibited greater failure resistance than vertical ones. Even at 25% infill density, horizontal specimens outperformed vertical specimens at 100% infill density, highlighting the influence of orientation. The Wöhler model is used to model the polylactide fatigue behavior. An ANOVA analysis is then performed to assess with higher accuracy the sensitivity of the number of cycles to failure to the applied stress, the infill density, and the printing direction. Regression equations and response surfaces are obtained to enhance the knowledge. ANOVA results revealed R2 values of 76.14% for horizontal printing and 82.75% for vertical printing. For horizontal printing, σ was the most influential parameter (68.44%), while for vertical printing, all terms except f*f were significant, with σ contributing the most (59.19%). Fractography investigation are performed. The cross-sectional views of the broken specimens demonstrated beach marks on the fracture surface of the fibers, indicating cyclic loading. Additionally, cleavage facets observed on the fracture surface confirmed that a brittle fracture had occurred.
Young plantation trees are often highly vulnerable to insect herbivory in ways that are difficult to predict as underlying mechanisms linked to plant traits and natural enemy pressure interact in context-dependent ways. We compared bottom-up and top-down forces acting on spruce budworm ( Choristoneura fumiferana ) on young white spruce ( Picea glauca ) trees in plantations vs in natural regeneration under hardwood canopy. Recognized as the most important outbreaking conifers defoliator in Eastern Canada, we aim to better understand how its herbivory on young trees can affect post-outbreak forest succession. We conducted a 4-year field survey in Northwestern Québec, Canada, to compare plant phenology, budworm density, defoliation rates, predator populations, and parasitism between two habitats. We also designed manipulative experiments with sentinel larvae to assess bottom-up and top-down forces in these habitats. The field survey showed earlier budburst phenology in plantation trees, which improves synchronization with a model (BioSIM) predicted timing of budworm emergence from diapause. The field survey showed higher budworm density and lower larval parasitism in plantations, but no significant difference in current-year growth defoliation during the initial outbreak phase. The bottom-up experiment showed slightly better budworm biological performance, indicated by higher pupal mass, in plantations. The top-down experiment showed greater predator and parasitoid pressure in the understory. Together, our results show how mechanisms controlling insect defoliator populations are context-dependent. In plantations both bottom-up and top-down forces on the spruce budworm are relaxed in these open habitats, leading to better biological performance and higher population density of this forest pest.
Objective An increase in medical cannabis and prescribed cannabinoids use for chronic pain management has been observed in Canada in the past years. This study aimed to: 1) Describe clinicians' perceived risk associated with the use of medical cannabis and prescribed cannabinoids for the management of chronic pain; and 2) Identify sociodemographic and professional factors associated with perceived risk of adverse effects. Method A web-based cross-sectional study was conducted in Quebec, Canada in 2022. A convenience sample of 207 clinicians was recruited (physicians/pharmacists/nurse practitioners). They were asked to rate the risk of adverse effects associated with medical cannabis (e.g., smoke, or oil) and prescribed cannabinoids (e.g., nabilone) on a scale of 0 to 10 (0: no risk, 10: very high risk), respectively. Multiple linear regression was performed to identify factors associated with perceived risk. Results Average perceived risk associated with medical cannabis and prescribed cannabinoids were 5.93 ± 2.08 (median:6/10) and 5.76 ± 1.81 (median:6/10). Factors associated with higher medical cannabis perceived risk were working in primary care (β = 1.38, p = .0034) or in another care setting (β = 1.21, p = .0368) as compared to a hospital setting. As for prescribed cannabinoids, being a pharmacist (β = 1.14, p = .0452), working in a primary care setting (β = 0.83, p = .0408) and reporting more continuing education about chronic pain (β = 0.02, p = .0416) were associated with higher perceived risk. No sex differences were found in terms of perceived risk. Conclusions Considering the clinician's experience provide insights on cannabis risk as these professionals are at the forefront of patient care when they encounter adverse effects.
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1,308 members
Yves Bergeron
  • Forest Research Institute (IRF)
Terence Epule Epule
  • Research Institute of Mining and Environment (IRME)(URDAAT)
Marie Guittonny
  • Research Institute of Mining and Environment (IRME)
Bruno Bussière
  • Research Institute of Mining and Environment (IRME)
Vincent Cloutier
  • Research Institute of Mining and Environment (IRME)
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Rouyn-Noranda, Canada
Head of institution
Denis Martel