Récurrence des inondations et édification des plaines alluviales des bassins du centre-sud du Québec (Canada)

Il existe un grand nombre de travaux sur la formation des plaines alluviales et des systèmes fluviaux en général. Toutefois, on compte un nombre plus restreint de travaux portant sur l’analyse et la caractérisation des sols alluviaux et des paléosols en terrasse. Cet article présente une analyse de la dynamique fluviale portant sur la récurrence des inondations, l’édification des plaines et la formation des sols dans les zones d’alluvionnement. La région d’étude couvre les bassins et sous-bassins du centre-sud du fleuve Saint-Laurent (rivières Saint-François, Massawippi, Magog et Eaton) affectés par des inondations périodiques. L’analyse des plaines alluviales des différents secteurs d’étude révèle des phases d’alluvionnement actives dans la plupart des secteurs d’étude. Les taux de sédimentation évalués à partir des datations 14C et des accumulations alluvionnaires se situent entre 0,15 et 0,76 cm a‑1 suivant les secteurs d’étude. Ces accumulations constantes entraînent un rehaussement des plaines alluviales et un faible développement pédogénétique des sols alluviaux. Ces sols sont regroupés parmi les régosols et les brunisols. Au niveau des caractéristiques granulométriques et sédimentologiques, les sols alluviaux présentent des faciès relativement homogènes et sans grande variabilité texturale. Ce sont essentiellement des matrices fines qui dominent avec des proportions importantes de limons ou de sables limoneux. L’analyse détaillée des sols révèle une faible différentiation du profil, l’absence d’horizon organo-minéral (Ah) et d’horizon illuvial (B), et une altération réduite. Le rehaussement progressif des plaines alluviales et le faible développement pédogénétique des sols alluviaux pourraient être en lien avec l’augmentation des inondations qui sont en hausse depuis le dernier siècle, et en particulier ces dernières décennies.Many studies have been conducted on the geomorphology and sedimentology of river terraces. In particular, studies have been carried out on the morpho-sedimentological evolution of floodplains and the hydro-climatic conditions associated with these environments, as well as on the relationships between variations in the hydrological system, the frequency and scope of flooding, and the sedimentological and stratigraphic sequences. This article presents an analysis concerning the fluvial dynamics responsible for the aggradation rates and pedogenesis processes observed in floodplains, and also considers the historical and chronological reconstruction of flood events. The study area covers the basins and sub-basins of the south-central part of the St. Lawrence River area (Saint-François, Massawippi, Magog and Eaton rivers) affected by periodic floods. The sedimentation rates estimated from radiocarbon-14 dating and from alluvial deposits range from 0.15 to 0.76 cm y‑1 depending on the study sites. The analysis of floodplains reveals important sedimentation rates connected to the frequency of floods that characterizes this hydrographic basin. The soil profiles were classified among the regosolic and brunisolic orders. For textural and sedimentological characteristics, the soils present relatively homogeneous facies and weak textural variability. They are essentially fine matrices dominated with an important proportion of silt or silty sand. The analysis of soil profiles reveals a weak pedogenesis development (e.g. weak horizonation, absence of organo-mineral (Ah) and illuvial horizons (B), weak weathering). The accumulation of sediments which causes substantial increases in floodplains levels and also the characteristics of soil profiles suggest that the frequency of floods is increasing since the beginning of the century and more particularly during recent decades

Theory-based practice as plural interpretations: A case of the the integration of the Humanbecoming theory in a palliative care setting

Nurses and students are generally encouraged to base their practice on nursing grand theories and models. However, the concrete benefits of these models in practice are often debated. Given that past studies were mostly dedicated to documenting the benefits of nursing theories in practice and were conducted by their supporters, their contribution to the debate is questionable. In 2012, we conducted a retrospective case study in a palliative care unit in Canada where caregivers have based their practice on the Humanbecoming theory since two years. We aimed to examine the process of integration and its effects. Data was obtained from individual interviews, direct observation and documents were analyzed using a network analysis method. Results suggest that integrating a grand theory in practice implies plural interpretations of what constitutes good practice, which brings about various effects, including some that are unexpected. The authors challenge the belief that theories and models necessarily have positive effects in practice. Résumé Les infirmières et les étudiantes sont généralement encouragées à fonder leur pratique sur les modèles et théories à large spectre en sciences infirmières. Cependant, les avantages concrets de ces modèles en pratique sont souvent débattus. Étant donné que les études antérieures étaient principalement dédiés à documenter les avantages des théories infirmières en pratique, et que ces études étaient menées par des partisans, leur contribution au débat en était affaiblie. En 2012, nous avons mené une étude de cas rétrospective dans une unité de soins palliatifs au Canada où les soignants basaient leur pratique sur la théorie de l’Humaindevenant depuis deux ans. Notre but était d’examiner le processus d’intégration et ses effets. Les données ont été obtenues à partir d’entrevues individuelles et d’observations directes. De plus, des documents ont été examinés par une méthode d’analyse de réseau. Les résultats suggèrent que le fait d’intégrer une théorie à large spectre en pratique implique de multiples interprétations de ce qui constitue une bonne pratique, ce qui entraine des effets divers, incluant certains effets inattendus. Les auteurs remettent en question la croyance selon laquelle les théories et modèles ont forcément des effets positifs dans la pratique

Different temporal trends in vascular plant and bryophyte communities along elevational gradients over four decades

Despite many studies showing biodiversity responses to warming, the generality of such responses across taxonomic groups remains unclear. Very few studies have tested for evidence of bryophyte community responses to warming, even though bryophytes are major contributors to diversity and functioning in many ecosystems. Here, we report an empirical study comparing long-term change in bryophyte and vascular plant communities in two sites with contrasting long-term warming trends, using "legacy" botanical records as a baseline for comparison with contemporary resurveys. We hypothesized that ecological changes would be greater in sites with a stronger warming trend and that vascular plant communities, with narrower climatic niches, would be more sensitive than bryophyte communities to climate warming. For each taxonomic group in each site, we quantified the magnitude of changes in species' distributions along the elevation gradient, species richness, and community composition. We found contrasted temporal changes in bryophyte vs. vascular plant communities, which only partially supported the warming hypothesis. In the area with a stronger warming trend, we found a significant increase in local diversity and dissimilarity (beta-diversity) for vascular plants, but not for bryophytes. Presence-absence data did not provide sufficient power to detect elevational shifts in species distributions. The patterns observed for bryophytes are in accordance with recent literature showing that local diversity can remain unchanged despite strong changes in composition. Regardless of whether one taxon is systematically more or less sensitive to environmental change than another, our results suggest that vascular plants cannot be used as a surrogate for bryophytes in terms of predicting the nature and magnitude of responses to warming. Thus, to assess overall biodiversity responses to global change, abundance data from different taxonomic groups and different community properties need to be synthesized.Peer reviewe

Benefits and Challenges of Multidisciplinary Project Teams: Lessons Learned for Researchers and Practitioners

Adopting a multidisciplinary research approach would enable test and evaluation professionals to more effective!y investigate the complex human performance problems faced in today\u27s technologically advanced operational domains. To illustrate the utility of this approach, we present lessons learned based on our experiences as a multi-agency, multidisciplinary team collaborating on an Army research project involving a dynamic military command and control simulation. Our goal with these lessons learned is to provide guidance to researchers and practitioners alike concerning the benefits and challenges of such collaboration. Our project team\u27s diverse members, drawn from both industry and government organizations, offer their multiple p perspectives on these issues. The final sections then summarize the challenges and benefits of multidisciplinary research

Comparative Assessment of Soil Contamination by Lead and Heavy Metals in Riparian and Agricultural Areas (Southern Québec, Canada)

Soils contaminated with hydrocarbons (C10–C50), PAHS, lead and other heavy metals were recently found in the banks of two major rivers in southern Québec. Alluvial soils are contaminated over a distance of 100 kilometers. Eight sampling sites, including some located in agriculture areas (farm woodlots) have been selected to compare air pollution (aerosol fallout and rainout) and river pollution values. The concentrations detected in soil profiles for As, Cd and Pb vary between 3.01 to 37.88 mg kg−1 (As), 0.11 to 0.81 mg kg−1 (Cd) 12.32 to 149.13 mg kg−1 (Pb). These metallic elements are considered highly toxic and can harm wildlife and human health at high levels. The maximum concentration of Pb (149.13 mg kg−1) in soils of the riparian zone is twelve times higher than the average Pb concentration found in a natural state evaluated at 15.3 mg kg−1 (SD 17.5). Pb concentrations in soils of agricultural areas (woodland control sites) range between 12 and 22 mg kg−1, and given that these values are recorded in surrounding cultivated land, the issue of the quality of agricultural products (crops and forage) to feed livestock or destined for human consumption must be further addressed in detail

UNBOUND

UNBOUND showcases the graduating class from the fashion design school at Fanshawe College.https://first.fanshawec.ca/famd_design_fashiondesign_unbound/1007/thumbnail.jp

Projecting ocean acidification impacts for the Gulf of Maine to 2050: new tools and expectations

© The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Siedlecki, S. A., Salisbury, J., Gledhill, D. K., Bastidas, C., Meseck, S., McGarry, K., Hunt, C. W., Alexander, M., Lavoie, D., Wang, Z. A., Scott, J., Brady, D. C., Mlsna, I., Azetsu-Scott, K., Liberti, C. M., Melrose, D. C., White, M. M., Pershing, A., Vandemark, D., Townsend, D. W., Chen, C,. Mook, W., Morrison, R. Projecting ocean acidification impacts for the Gulf of Maine to 2050: new tools and expectations. Elementa: Science of the Anthropocene, 9(1), (2021): 00062, https://doi.org/10.1525/elementa.2020.00062.Ocean acidification (OA) is increasing predictably in the global ocean as rising levels of atmospheric carbon dioxide lead to higher oceanic concentrations of inorganic carbon. The Gulf of Maine (GOM) is a seasonally varying region of confluence for many processes that further affect the carbonate system including freshwater influences and high productivity, particularly near the coast where local processes impart a strong influence. Two main regions within the GOM currently experience carbonate conditions that are suboptimal for many organisms—the nearshore and subsurface deep shelf. OA trends over the past 15 years have been masked in the GOM by recent warming and changes to the regional circulation that locally supply more Gulf Stream waters. The region is home to many commercially important shellfish that are vulnerable to OA conditions, as well as to the human populations whose dependence on shellfish species in the fishery has continued to increase over the past decade. Through a review of the sensitivity of the regional marine ecosystem inhabitants, we identified a critical threshold of 1.5 for the aragonite saturation state (Ωa). A combination of regional high-resolution simulations that include coastal processes were used to project OA conditions for the GOM into 2050. By 2050, the Ωa declines everywhere in the GOM with most pronounced impacts near the coast, in subsurface waters, and associated with freshening. Under the RCP 8.5 projected climate scenario, the entire GOM will experience conditions below the critical Ωa threshold of 1.5 for most of the year by 2050. Despite these declines, the projected warming in the GOM imparts a partial compensatory effect to Ωa by elevating saturation states considerably above what would result from acidification alone and preserving some important fisheries locations, including much of Georges Bank, above the critical threshold.This research was financially supported by the Major Special Projects of the Ministry of Science and Technology of China (2016YFC020600), the Young Scholars Science Foundation of Lanzhou Jiaotong University (2018033), and the Talent Innovation and Entrepreneurship Projects of Lanzhou (2018-RC-84)

A Novel Role for MAPKAPK2 in Morphogenesis during Zebrafish Development

One of the earliest morphogenetic processes in the development of many animals is epiboly. In the zebrafish, epiboly ensues when the animally localized blastoderm cells spread, thin over, and enclose the vegetally localized yolk. Only a few factors are known to function in this fundamental process. We identified a maternal-effect mutant, betty boop (bbp), which displays a novel defect in epiboly, wherein the blastoderm margin constricts dramatically, precisely when half of the yolk cell is covered by the blastoderm, causing the yolk cell to burst. Whole-blastoderm transplants and mRNA microinjection rescue demonstrate that Bbp functions in the yolk cell to regulate epiboly. We positionally cloned the maternal-effect bbp mutant gene and identified it as the zebrafish homolog of the serine-threonine kinase Mitogen Activated Protein Kinase Activated Protein Kinase 2, or MAPKAPK2, which was not previously known to function in embryonic development. We show that the regulation of MAPKAPK2 is conserved and p38 MAP kinase functions upstream of MAPKAPK2 in regulating epiboly in the zebrafish embryo. Dramatic alterations in calcium dynamics, together with the massive marginal constrictive force observed in bbp mutants, indicate precocious constriction of an F-actin network within the yolk cell, which first forms at 50% epiboly and regulates epiboly progression. We show that MAPKAPK2 activity and its regulator p38 MAPK function in the yolk cell to regulate the process of epiboly, identifying a new pathway regulating this cell movement process. We postulate that a p38 MAPKAPK2 kinase cascade modulates the activity of F-actin at the yolk cell margin circumference allowing the gradual closure of the blastopore as epiboly progresses