Étude de l'infiltration et des variations verticales de la pression interstitielle dans un massif argileux

La vallée du Saint-Laurent est caractérisée par la présence d’argiles marines post-glaciaires susceptibles aux glissements de terrain. Un des facteurs responsables pour le développement des glissements de terrain est l’augmentation des pressions interstitielles dû à l’infiltration importante de l’eau dans le sol, ce qui réduit la contrainte effective du sol. Cette étude vise à comprendre la réponse des pressions interstitielles aux événements climatiques dans les dépôts argileux, ce qui permettra une meilleure compréhension des mécanismes qui entrainent les glissements de terrain et permettra d’aider à réduire leur impact. Le site d’étude est un terrain plat situé à Sainte-Anne-de-la-Pérade. La stratigraphie est caractérisée par la présence de deux couches argileuses, en alternance avec des couches de sable et de silt. Le site a été instrumenté à haute résolution spatiale et temporelle afin d’obtenir les données des conditions climatiques et les conditions hydrogéologiques et géotechniques du sol. Des essais ont aussi été réalisés en laboratoire et sur le terrain afin d’obtenir les propriétés géotechniques et hydrodynamiques des différentes couches de sol. Puis, une compensation barométrique par régression linéaire été appliquée pour les données de pressions interstitielles. Les résultats obtenus ont permis de réaliser des simulations afin de tenter de reproduire les données du site d’étude. L’interprétation des résultats a permis d’établir en premier lieu l’effet du climat sur l’infiltration de l’eau, qui dépend des précipitations, de la température et du gel du sol. Puis, les mécanismes responsables des variations de pressions interstitielles ont été identifiés, soit le climat, les propriétés des couches de sol ainsi que la rivière Sainte-Anne à proximité. L’interprétation des données et des simulations a permis de produire un modèle conceptuel représentant l’écoulement de l’eau souterraine. Finalement, le potentiel de glissement de terrain a été évalué pour le site et a été jugé faible dans les conditions actuelles.The St-Lawrence Valley is characterized by thick and extensive post-glacial marine clay deposits that are susceptible to landslides. One important factor responsible for landslide development is the important pore water pressure increase due to the significant infiltration of water into the soil, which reduces the effective strength in the soil. This study aims at understanding pore pressure response to climatic events in clay deposits which will lead to a better knowledge of the mechanisms that trigger landslides and could help to reduce their impact. The study site is a flat terrain located in Ste-Anne-de-la-Pérade. The stratigraphy is characterized by two clay layers, alternating with sand and silt layers. The study relies on high resolution spatial and temporal meteorological, geotechnical and hydrogeological observations. Laboratory tests on samples from the site and field investigations were done in order to measure the geotechnical and hydraulic properties of the soils. Barometric compensation by linear regression was also applied on pore pressure data. The results obtained allowed us to realise simulation in order to try to reproduce the study site data. The interpretation of the results firstly established the effect of the climate on the infiltration of water, which depends on precipitation, temperature and freezing of the soil. Then, the mechanisms responsible for variations in pore pressures were identified, which are the climate, the properties of the soil layers and the nearby Ste-Anne River. Interpreting data and simulations led to a conceptual model representing the flow of groundwater. Finally, landslide potential was assessed for the site and was considered low under current conditions

Field performance of four vibrating-wire piezometer installation methods

Vibrating wire piezometers provide a number of advantages over the traditional hydraulic piezometer design. There are many methods and configurations for installing vibrating-wire piezometers, with the most common being: single piezometers in sand packs (SP), multilevel piezometers in sand packs (MLSP), and fully-grouted multilevel piezometers using either bentonite (FGB) or cement-bentonite grout (FGCB). This study assesses the performance of these four different installation methods for vibrating wire piezometers at a field site possessing complex stratigraphy, including glacial and marine sediments. Pore pressure data recorded between December 2017 and July 2019 were analyzed to accomplish this objective. Data indicate that SP, MLSP, and FGB piezometers performed well. This determination is based on the fact that piezometers installed at the same depth with these arrangements recorded similar pressure variations that were coherent with the hydrogeological setting. Of the two fully-grouted installations using cement-bentonite grout, one installation failed completely due to a hydraulic short circuit, caused either by shrinkage of the grout or flow occurring along the wires of the embedded instruments. While the FGB-type piezometers used in this study worked correctly, the lack of standard methods concerning both the construction of fully-grouted piezometers is concerning. Furthermore, the lack of a standard method for mixing cement-bentonite grout likely contributed to the failure of the FGCB installations. Thus, due to the lack of guidance for both construction and grout preparation, the use of a bentonite grout removes a degree of uncertainty when fully-grouted installation techniques are used

Hydrogeology of a complex Champlain Sea deposit (Quebec, Canada) : implications for slope stability

The thick sequences of marine clayey deposits which blanket the St. Lawrence Lowlands in south-eastern Canada are highly susceptible to landslides. With 89% of the population of the Province of Quebec living in this region, improving our understanding of the mechanisms causing landslides in these sediments is a matter of public security. To accomplish this goal, instruments were deployed at a field site in Sainte-Anne-de-la-Pérade, Quebec, Canada to monitor atmospheric, soil, and groundwater conditions. Field and laboratory measurements of soil geotechnical and hydraulic properties were also performed. Results indicate that the groundwater and pore pressure dynamics at the site cannot be explained using simplified site conceptual models. Further analysis indicates that groundwater dynamics and pore pressures in the massive clay deposits on-site are determined by (i) the highly-heterogeneous nature of the local geological materials (ii) the contrasting hydraulic and geotechnical properties of these materials, (iii) the presence of two unconfined aquifers at the site, one surficial and one at depth, and (iv), the presence of the Sainte-Anne River. These results were used to create a new conceptual model which illustrates the complex groundwater flow system present on site, and shows the importance of including hydrogeologic context in slope stability analysis

Microprojection arrays applied to skin generate mechanical stress, induce an inflammatory transcriptome and cell death, and improve vaccine-induced immune responses

Abstract: Chemical adjuvants are typically used to improve immune responses induced by immunisation with protein antigens. Here we demonstrate an approach to enhance immune responses that does not require chemical adjuvants. We applied microprojection arrays to the skin, producing a range of controlled mechanical energy to invoke localised inflammation, while administering influenza split virus protein antigen. We used validated computational modelling methods to identify links between mechanical stress and energy generated within the skin strata and resultant cell death. We compared induced immune responses to those induced by needle-based intradermal antigen delivery and used a systems biology approach to examine the nature of the induced inflammatory response, and correlated this with markers of cell stress and death. Increasing the microprojection array application energy and the addition of QS-21 adjuvant were each associated with enhanced antibody response to delivered antigen and with induction of gene transcriptions associated with TNF and NF-κB signalling pathways. We concluded that microprojection intradermal antigen delivery inducing controlled local cell death could potentially replace chemical adjuvants to enhance the immune response to protein antigen

Portrait des ressources en eau souterraine des îles de la Madeleine : atlas hydrogéologique

L’eau souterraine constitue l’unique source d’approvisionnement en eau potable des îles de la Madeleine. Elle est vulnérable à l’intrusion d’eau salée qui provient de la mer et aux nombreuses activités humaines qui peuvent avoir un impact sur la quantité ou la qualité de la ressource. Les changements climatiques pourraient aussi influer sur la disponibilité future de cette ressource. Une connaissance accrue sur l’eau souterraine et les aquifères qui la contiennent est nécessaire pour la mise en place de mesures de protection et de gestion durable de la ressource. La présente étude établit le Portrait des ressources en eau souterraine des îles de la Madeleine en recensant d’abord l’ensemble des connaissances existantes sur les eaux souterraines du territoire d’étude. Des données complémentaires de terrain ont ensuite été acquises. L’ensemble des informations récoltées ont enfin été intégrées et interprétées en format cartographique, principalement à l’aide d’une approche méthodologique basée sur la modélisation numérique des écoulements. Les aquifères au potentiel d’exploitation moyen à très élevé, composés principalement de grès, ont été identifiés. Ceux-ci contiennent la presque totalité de l’eau souterraine qui est actuellement exploitée et constituent la réserve principale en eau douce disponible pour les besoins futurs. Cette eau est de très bonne qualité et peut souvent être distribuée sans traitement particulier. Les aires d’alimentation de ces aquifères correspondent aux territoires qui devraient être ciblés par les mesures de protection et de gestion de la ressource. La consommation annuelle en eau douce est faible comparativement à la réalimentation annuelle des aquifères. Ainsi, la quantité d’eau contenue dans les aquifères suffit aux besoins en eau potable actuels. Les ressources en eau souterraine et les réseaux d'exploitation actuels semblent suffisants pour les besoins futurs de la municipalité selon les projections en 2050 de la hausse de la consommation et de la diminution du volume d’eau disponible causée par les changements climatiques

Portrait des ressources en eau souterraine des îles de la Madeleine : rapport scientifique

L’eau souterraine constitue l’unique source d’approvisionnement en eau potable des îles de la Madeleine. Elle est vulnérable à l’intrusion d’eau salée qui provient de la mer et aux nombreuses activités humaines qui peuvent avoir un impact sur la quantité ou la qualité de la ressource. Les changements climatiques pourraient aussi influer sur la disponibilité future de cette ressource. Une connaissance accrue sur l’eau souterraine et les aquifères qui la contiennent est nécessaire pour la mise en place de mesures de protection et de gestion durable de la ressource. La présente étude établit le Portrait des ressources en eau souterraine des îles de la Madeleine en recensant d’abord l’ensemble des connaissances existantes sur les eaux souterraines du territoire d’étude. Des données complémentaires de terrain ont ensuite été acquises. L’ensemble des informations récoltées ont enfin été intégrées et interprétées en format cartographique, principalement à l’aide d’une approche méthodologique basée sur la modélisation numérique des écoulements. Les aquifères au potentiel d’exploitation moyen à très élevé, composés principalement de grès, ont été identifiés. Ceux-ci contiennent la presque totalité de l’eau souterraine qui est actuellement exploitée et constituent la réserve principale en eau douce disponible pour les besoins futurs. Cette eau est de très bonne qualité et peut souvent être distribuée sans traitement particulier. Les aires d’alimentation de ces aquifères correspondent aux territoires qui devraient être ciblés par les mesures de protection et de gestion de la ressource. La consommation annuelle en eau douce est faible comparativement à la réalimentation annuelle des aquifères. Ainsi, la quantité d’eau contenue dans les aquifères suffit aux besoins en eau potable actuels. Les ressources en eau souterraine et les réseaux d'exploitation actuels semblent suffisants pour les besoins futurs de la municipalité selon les projections en 2050 de la hausse de la consommation et de la diminution du volume d’eau disponible causée par les changements climatiques

Safety, tolerability, and immunogenicity of influenza vaccination with a high-density microarray patch: Results from a randomized, controlled phase I clinical trial.

BACKGROUND: The Vaxxas high-density microarray patch (HD-MAP) consists of a high density of microprojections coated with vaccine for delivery into the skin. Microarray patches (MAPs) offer the possibility of improved vaccine thermostability as well as the potential to be safer, more acceptable, easier to use, and more cost-effective for the administration of vaccines than injection by needle and syringe (N&S). Here, we report a phase I trial using the Vaxxas HD-MAP to deliver a monovalent influenza vaccine that was to the best of our knowledge the first clinical trial to evaluate the safety, tolerability, and immunogenicity of lower doses of influenza vaccine delivered by MAPs. METHODS AND FINDINGS: HD-MAPs were coated with a monovalent, split inactivated influenza virus vaccine containing A/Singapore/GP1908/2015 H1N1 haemagglutinin (HA). Between February 2018 and March 2018, 60 healthy adults (age 18-35 years) in Melbourne, Australia were enrolled into part A of the study and vaccinated with either: HD-MAPs delivering 15 μg of A/Singapore/GP1908/2015 H1N1 HA antigen (A-Sing) to the volar forearm (FA); uncoated HD-MAPs; intramuscular (IM) injection of commercially available quadrivalent influenza vaccine (QIV) containing A/Singapore/GP1908/2015 H1N1 HA (15 μg/dose); or IM injection of H1N1 HA antigen (15 μg/dose). After 22 days' follow-up and assessment of the safety data, a further 150 healthy adults were enrolled and randomly assigned to 1 of 9 treatment groups. Participants (20 per group) were vaccinated with HD-MAPs delivering doses of 15, 10, 5, 2.5, or 0 μg of HA to the FA or 15 μg HA to the upper arm (UA), or IM injection of QIV. The primary objectives of the study were safety and tolerability. Secondary objectives were to assess the immunogenicity of the influenza vaccine delivered by HD-MAP. Primary and secondary objectives were assessed for up to 60 days post-vaccination. Clinical staff and participants were blind as to which HD-MAP treatment was administered and to administration of IM-QIV-15 or IM-A/Sing-15. All laboratory investigators were blind to treatment and participant allocation. Two further groups in part B (5 participants per group), not included in the main safety and immunological analysis, received HD-MAPs delivering 15 μg HA or uncoated HD-MAPs applied to the forearm. Biopsies were taken on days 1 and 4 for analysis of the cellular composition from the HD-MAP application sites. The vaccine coated onto HD-MAPs was antigenically stable when stored at 40°C for at least 12 months. HD-MAP vaccination was safe and well tolerated; any systemic or local adverse events (AEs) were mild or moderate. Observed systemic AEs were mostly headache or myalgia, and local AEs were application-site reactions, usually erythema. HD-MAP administration of 2.5 μg HA induced haemagglutination inhibition (HAI) and microneutralisation (MN) titres that were not significantly different to those induced by 15 μg HA injected IM (IM-QIV-15). HD-MAP delivery resulted in enhanced humoral responses compared with IM injection with higher HAI geometric mean titres (GMTs) at day 8 in the MAP-UA-15 (GMT 242.5, 95% CI 133.2-441.5), MAP-FA-15 (GMT 218.6, 95% CI 111.9-427.0), and MAP-FA-10 (GMT 437.1, 95% CI 254.3-751.3) groups compared with IM-QIV-15 (GMT 82.8, 95% CI 42.4-161.8), p = 0.02, p = 0.04, p < 0.001 for MAP-UA-15, MAP-FA-15, and MAP-FA-10, respectively. Higher titres were also observed at day 22 in the MAP-FA-10 (GMT 485.0, 95% CI 301.5-780.2, p = 0.001) and MAP-UA-15 (367.6, 95% CI 197.9-682.7, p = 0.02) groups compared with the IM-QIV-15 group (GMT 139.3, 95% CI 79.3-244.5). Results from a panel of exploratory immunoassays (antibody-dependent cellular cytotoxicity, CD4+ T-cell cytokine production, memory B cell (MBC) activation, and recognition of non-vaccine strains) indicated that, overall, Vaxxas HD-MAP delivery induced immune responses that were similar to, or higher than, those induced by IM injection of QIV. The small group sizes and use of a monovalent influenza vaccine were limitations of the study. CONCLUSIONS: Influenza vaccine coated onto the HD-MAP was stable stored at temperatures up to 40°C. Vaccination using the HD-MAP was safe and well tolerated and resulted in immune responses that were similar to or significantly enhanced compared with IM injection. Using the HD-MAP, a 2.5 μg dose (1/6 of the standard dose) induced HAI and MN titres similar to those induced by 15 μg HA injected IM. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry (ANZCTR.org.au), trial ID 108 ACTRN12618000112268/U1111-1207-3550

Asgard/NOTT: L-band nulling interferometry at the VLTI I. Simulating the expected high-contrast performance

Context: NOTT (formerly Hi-5) is a new high-contrast L' band (3.5-4.0 \textmu m) beam combiner for the VLTI with the ambitious goal to be sensitive to young giant exoplanets down to 5 mas separation around nearby stars. The performance of nulling interferometers in these wavelengths is affected both by fundamental noise from the background and by the contributions of instrumental noises. This motivates the development of end-to-end simulations to optimize these instruments. Aims: To enable the performance evaluation and inform the design of such instruments on the current and future infrastructures, taking into account the different sources of noise, and their correlation. Methods: SCIFYsim is an end-to-end simulator for single mode filtered beam combiners, with an emphasis on nulling interferometers. It is used to compute a covariance matrix of the errors. Statistical detection tests based on likelihood ratios are then used to compute compound detection limits for the instrument. Results: With the current assumptions on the performance of the wavefront correction systems, the errors are dominated by correlated instrumental errors down to stars of magnitude 6-7 in the L band, beyond which thermal background from the telescopes and relay system becomes dominant. Conclusions: SCIFYsim is suited to anticipate some of the challenges of design, tuning, operation and signal processing for integrated optics beam combiners. The detection limits found for this early version of NOTT simulation with the unit telescopes are compatible with detections at contrasts up to $10^5$ in the L band at separations of 5 to 80 mas around bright stars

Microarray patch delivery of un-adjuvanted influenza vaccine induces potent and broad-spectrum immune responses in a phase I clinical trial

Microarray patches (MAPs) offer the possibility of improved vaccine thermostability and dose-sparing potential as well as the potential to be safer, more acceptable, easier to use and more cost-effective for the administration of vaccines than injection by needle and syringe. Here, we report a phase I trial (ACTRN12618000112268/ U1111-1207-3550) using the Vaxxas high-density MAP (HD-MAP) to deliver a monovalent influenza vaccine to evaluate the safety, tolerability, and immunogenicity of lower doses of influenza vaccine delivered by MAPs. To the best of our knowledge, this is the first study determining dose reduction potential using MAPs in humans. Monovalent, split inactivated influenza virus vaccine containing A/Singapore/GP1908/ 2015 [H1N1] haemagglutinin (HA) was delivered by MAP into the volar forearm or upper arm, or given intramuscularly (IM) once. Participants (20 per group) received HD-MAPs delivering doses of 15, 10, 5, 2.5 or 0 µg of HA or an IM injection of quadrivalent influenza vaccine (QIV). In two subgroups, skin biopsies were taken on days 1 (pre-vaccination) and 4 for analysis of the cellular composition from the HD-MAP application sites. All laboratory investigators were blind to treatment and participant allocation. The primary objectives of the study were safety and tolerability. Secondary objectives included immunogenicity and dose de-escalation assessments of the influenza vaccine delivered by HD-MAP. Both objectives were assessed for up to 60 days post-vaccination. Please click Download on the upper right corner to see the full abstract

Asgard/NOTT: L-band nulling interferometry at the VLTI. II. Warm optical design and injection system

Asgard/NOTT (previously Hi-5) is a European Research Council (ERC)-funded project hosted at KU Leuven and a new visitor instrument for the Very Large Telescope Interferometer (VLTI). Its primary goal is to image the snow line region around young stars using nulling interferometry in the L-band (3.5 to 4.0)$\mu$m, where the contrast between exoplanets and their host stars is advantageous. The breakthrough is the use of a photonic beam combiner, which only recently allowed the required theoretical raw contrast of $10^{-3}$ in this spectral range. Nulling interferometry observations of exoplanets also require a high degree of balancing between the four pupils of the VLTI in terms of intensity, phase, and polarization. The injection into the beam combiner and the requirements of nulling interferometry are driving the design of the warm optics and the injection system. The optical design up to the beam combiner is presented. It offers a technical solution to efficiently couple the light from the VLTI into the beam combiner. During the coupling, the objective is to limit throughput losses to 5% of the best expected efficiency for the injection. To achieve this, a list of different loss sources is considered with their respective impact on the injection efficiency. Solutions are also proposed to meet the requirements on beam balancing for intensity, phase, and polarization. The different properties of the design are listed, including the optics used, their alignment and tolerances, and their impact on the instrumental performances in terms of throughput and null depth. The performance evaluation gives an expected throughput loss of less than <6.4% of the best efficiency for the injection and a null depth of $\sim2.10^{-3}$, mainly from optical path delay errors outside the scope of this work.Comment: Accepted for publication in JATIS. 23 pages, 11 figures, 8 table