identifier: Fournier, Catherine  (2022). Pratiques et approches déployées pour la prévention des risques liés aux inondations au Québec : Le cas des territoires concernés par les inondations du lac des Deux Montagnes  Mémoire.  Québec, Université du Québec, Institut national de la recherche scientifique, Maîtrise en études urbaines, 204 p.

subject:
gestion des risques
développement local
inondation
prévention
résilience
vulnérabilité
approche intégrée
sciences sociales
rivière des Outaouais
Québec (Canada)
risk management
local development
flood
prevention
resilience
vulnerability
integrated approach
social sciences
Ottawa River
Quebec (Canada)

abstract:
Les politiques québécoises de prévention des risques liés aux inondations ont été sujettes à débat ces dernières années, avec une remise en cause du modèle centralisé et uniforme à travers le Québec, pour une approche plus intégrée. Celle-ci fait notamment la promotion de mesures axées sur la vulnérabilité et d’une participation plus active des acteurs territoriaux. On en sait toutefois très peu sur les déclinaisons locales de l’approche intégrée dans le contexte québécois.
Ce mémoire propose d’interroger les différentes approches locales de la prévention et de soulever les enjeux qu’elles posent du point de vue des autorités qui y participent. L’étude se penche sur le cas des territoires concernés par les inondations du lac des Deux Montagnes (Région hydrographique de l'Outaouais et de Montréal).
Le cadre d’analyse met de l’avant l’approche des instruments d’action publique pour comprendre leur appropriation par les acteurs locaux et une approche pragmatique qui consiste à centrer notre regard sur les pratiques et les stratégies de réduction des risques d’inondation. La recherche s’appuie sur trois sources de données : une analyse documentaire des régimes provinciaux de régulation des risques d’inondation, un recensement des pratiques de prévention déployées par les autorités locales concernées par les inondations du lac des Deux Montagnes et une série de 15 entretiens réalisés avec les personnes travaillant au sein de ces différentes autorités.
Le cas illustre la difficulté et le faible engagement de prévenir les risques autrement que par l’approche de réduction de l’exposition aux risques imposée par la Politique de protection des rives, du littoral et des plaines inondables (PPRLPI). Toutefois, après les inondations de 2017 et de 2019, des approches alternatives propres aux contextes territoriaux ont été envisagées par différentes organisations. Celles-ci devraient davantage être documentées et mises en débat afin d’envisager un régime provincial de la gestion des risques plus flexible et ouvert à leur coexistence.

Uniformed and centralized model of Quebec's flood prevention policies have been recently debated. Integrated approach to flood risk prevention is now put forward, which focus more on vulnerability and foster an active participation of local authorities. Local declinations of the approach are relatively unknown in Quebec. This study presents different local approaches to flood risk prevention and raise issues they pose from the perspective of local authorities involved. It is based on the authority’s concerns by Lac des Deux Montagnes flooding (Outaouais and Montreal hydrographic region).
Combining a political sociology approach to policy instruments and a pragmatic approach, we focus on risk regulation regimes, practices and risk reduction strategies. Three sources of data were used: an analysis of flood risk regulation regimes, an inventory of prevention practices deployed by local authorities and 15 interviews conducted with professionals among these authorities.
Results show the difficulty and low commitment to implement local distinct approaches apart from prohibiting and discouraging exposure to flood risk enforced by the Protection Policy for Lakeshores, Riverbanks, Littoral Zones and Floodplains. However, after the floods of 2017 and 2019, alternative strategies specific to different territorial contexts were considered. These should be better documented and debated in order to consider a more flexible and coexistence provincial policy.


identifier: Zanotto, Luca  (2022). Development of a scanless terahertz time-domain imaging system.  Thèse.  Québec, Doctorat en sciences de l'énergie et des matériaux, Université du Québec, Institut national de la recherche scientifique, 165 p.

type:
Thèse
Non évalué par les pairs

subject: rayonnement térahertz

subject: spectroscopie dans le domaine temporel

subject: imagerie à « pixel unique »

subject: détection compressée

subject: détection « seul coup »

subject: terahertz radiation

subject: time-domain spectroscopy

subject: single-pixel imaging

subject: compressed sensing

subject: single-shot detection

abstract:
Au cours des vingt dernières années, l'imagerie térahertz basée sur la spectroscopie dans le domaine temporel provoque un intérêt croissant grâce à ses capacités particulières d’étudier les caractéristiques spectrales des produits chimiques, d’extraire l'indice de réfraction et l'absorption des matériaux, ainsi que de révéler la structure interne d’objets complexes. Cependant, son utilisation répandue a été entravée par le temps d'acquisition chronophage généralement nécessaire pour balayer spatialement l'objet et, pour chaque point spatial, enregistrer le champ dans le domaine temporel via une ligne à retard. Dans ce projet de recherche, nous avons abordé cet obstacle fondamental en utilisant deux approches complémentaires. Tout d'abord, nous avons mis en œuvre une configuration d'imagerie à « pixel unique » dans le domaine temporel, qui permet d'éviter le balayage spatial et d'utiliser une reconstruction de détection compressée. Nous avons démontré l'extraction cohérente des formes d'onde temporelles térahertz d’une façon indirecte, à chaque position spatiale d'un objet via l’imagerie à « pixel unique ». Cette stratégie permet ainsi de préserver les capacités de sonder les propriétés des matériaux, offertes par la spectroscopie dans le domaine temporel, tout en permettant une réduction du temps d'acquisition. Dans la deuxième partie, nous avons davantage amélioré l'arrangement d'imagerie en utilisant un schéma de détection sans balayage. En exploitant correctement la diffraction naturelle des ondes, un cartographie tempsespace appliquée à la détection de point térahertz permet une acquisition quasi instantanée des formes d'onde térahertz. La combinaison de ces deux approches permet une réduction significative de la complexité du système et du temps d'acquisition, et constitue ainsi une solution prometteuse pour le développement d'imageurs térahertz rapides et compacts de nouvelle génération.

In the last twenty years, terahertz imaging based on time-domain spectroscopy, has attracted increasingly growing attention thanks to its peculiar abilities to study spectral features of chemicals, extracting the refractive index and absorption of materials, as well as revealing the inner structure of complex objects. However, its widespread use has been hampered by the very long acquisition time typically required to perform a pixel-by-pixel scan of the object and, for each spatial point, record the field in time via a delay line. In this research project, we aimed to address this fundamental bottleneck by using two complementary approaches. First, we implemented a time-domain singlepixel imaging configuration, which avoids the spatial scan and makes it possible to use a compressed sensing reconstruction. We demonstrated the indirect coherent extraction of terahertz temporal waveforms at each spatial position of an object via single-pixel imaging. This strategy preserves the capabilities of probing material properties, offered by time-domain spectroscopy, while enabling a reduction of the acquisition time. In the second part, we further improved the imaging arrangement employing a scanless terahertz waveform detection scheme. By properly exploiting natural wave diffraction, a time-to-space encoding applied to terahertz point detection allows for an almost instantaneous capture of the terahertz waveforms. The combination of these two approaches leads to a significant reduction of both system complexity and acquisition time, and thus is a promising solution for the development of next-generation fast and compact terahertz imagers.


identifier: Zamal, Hasna Hena  (2022). Investigation of carbon nanotube/5-ethylidene-2-norbornene as micro-encapsulated healing agent for self-healing epoxy for aerospace applications.  Thèse.  Québec, Doctorat en sciences de l'énergie et des matériaux, Université du Québec, Institut national de la recherche scientifique, 175 p.

subject:
auto-réparants
polymérisation
epoxy
microencapsulation
nanotubes de carbone
aérospatial
conductivité électrique
ROMP
fracture
adhésif
self-healing
polymerization
epoxy
microencapsulation
carbon nanotubes
aerospace
electrical conductivity
ROMP
fracture
adhesive

abstract:
Les polymères auto-réparants à l’aide d’une polymérisation par ouverture de cycle par métathèse (ROMP, de l'anglais Ring-Opening Metathesis Polymerization) où les catalyseurs Hoveyda Grubbs (HG2) de seconde generation jouent le rôle d’initiateur et les monomères d’ethylidene-5- norbornene-2 (5E2N) celui d’agents réparateurs, sont des matériaux très prometteurs. Ceci est particulièrement vrai à basse température, dans un environnement correspondant à celui rencontré à l’intérieur d’un véhicule spatial en opération. Cependant, pour pouvoir les rendre apte à des applications dans l’espace, il existe encore de nombreux obstacles à surmonter, tels que ceux associés aux effets de la température sur la cinétique de réaction ROMP et son efficacité. Dans ce travail, une étude quantitative détaillée de la cinétique de réaction ROMP de systèmes 5E2N/HG2 a été menée en recourant à la spectroscopie Raman, pour des températures comprises entre la température de la pièce et -30°C. Cette analyse repose sur l’observation de pic phononiques associés au groupe fonctionnel caractéristique des liaisons C=C, et la mesure de leurs variations d'intensité spectrales et de leur surface intégrée, qui révèlent la progression de la réaction chimique au fil du temps. En utilisant le principe d’Arrhenius, les coefficients de variations apparentes ont été déterminés pour chaque température de réaction donnée, au moyen d’une relation cinétique de premier ordre. Les valeurs extraites des taux de variation observés et des énergies d’activation correspondantes sont en accord avec celles rapportées dans la littérature pour des réactions similaires. Nos expériences et notre méthodologie ont été spécialement mis au point pour permettre un contrôle efficace la réaction ROMP en dessous de 0 °C. Ceci nous a donné la possibilité d’étudier les effets de certains facteurs sur la vitesse de polymérisation au sein de différents systèmes auto-réparants, mais aussi de les optimiser en conséquent pour les adapter à des applications spécifiques. Considérant l’intérêt actuellement suscité par l’utilisation de nanotubes de carbone dans la réalisation de polymères avancés afin d’augmenter leurs performances structurelles et électriques, la micro-encapsulation de nanotubes de carbone au sein de monomères auto réparants comme le 5E2N peut potentiellement ouvrir de nouvelles voies technologiques très intéressantes, en conférant des propriétés d’auto-guérison électro-mécanique à des structures mécaniques et des équipements électroniques utilisés dans les véhicules aérospatiaux modernes. Dans notre travail, nous sommes parvenus à incorporer des nanotubes de carbone multi-parois (simplement notés CNTs dans la suite du texte) dans des micro-capsules contenant une solution de 5E2N liquide, enrobée d’une paroi en polymère, au moyen d’une méthode de polymérisation in-situ. Afin de s’assurer que ces matériaux étaient adaptés pour des applications réelles, les caractéristiques thermo-physiques de ces micro-capsules, incluant leurs tailles moyennes, formes, uniformités, l’intégrité structurelle et l’épaisseur de leurs parois, leur stabilité thermique et la nature de leur contenu ont été étudiés de manière intensive, en recourant aux techniques de microscopies optique et électronique, ainsi qu’aux analyses thermogravimétriques (TGA) et par calorimétrie différentielle à balayage (DSC). La présence de CNTs à l’intérieur du cœur liquide des microcapsules, leur dispersion effective une fois la paroi de la microcapsule déchirée, ainsi que leur capacité à se polymériser rapidement ont pu être constatés par analyses microscopiques, spectroscopiques et fracto-graphiques. Les polymères à base d’époxy servent à la fois de matériau matriciel aux composites laminés et d’adhésif ultra-performant dans les jointures collées, qu’on retrouve dans les pièces, structures et dispositifs employés dans l’industrie aérospatiale. L’époxy peut être sujet à plusieurs types d’endommagement, dépendamment des contraintes subies par le matériau, lesquels peuvent s’accumuler avec le temps jusqu’à entrainer une défaillance complète du système. Nous présentons une étude comparative des propriétés d’auto-guérison de polymères à base d’époxy auxquels des micro-capsules contenant un mélange CNT/5E2N ont été intégrés, pour deux différentes catégories de bris mécanique. Le rétablissement de systèmes dans lesquels ont été incorporées des capsules à base d’agents 5E2N et CNT/5E2N a été évalué et comparé sous l’effet d’un cisaillement laminaire et d’une charge de rupture verticale (mode I). Une fois les micro-capsules introduites dans l’époxy, nous démontrons que le système contenant des micro-capsules de CNT/5E2N possède d’excellentes capacités auto-curatives pour chacune de ces contraintes. Pour les tests effectués en mode de cisaillement laminaire et de charge de rupture verticale, l’utilisation d’un mélange CNT/5E2N à l’intérieur de micro-réservoir permet d’augmenter la résistance naturelle du milieu, ainsi que ses propriétés auto-réparatrices, bien mieux qu’en utilisant seulement un agent de 5E2N. Après rupture complète, 97% de la ténacité et 78% de la résistance au cisaillement du système sont restaurés avec des micro-capsules de CNT/5E2N, contre seulement 76% et 39% avec des micro capsules de 5E2N. Nos résultats suggèrent qu’en ingénierie spatiale avancée, un polymère structurel tel que celui réalisé à base d’époxy contenant des micro-capsules de CNT/5E2N peut servir à la fois de matrice auto-réparante très efficace dans les composites laminés de haute performance et de structure réparante adhésive dans les jointures collées. Lorsqu’elles sont employées dans les polymères conducteurs, nous montrons aussi que 82% de la conductivité électrique des échantillons est restituée de manière autonome à l’aide des micro capsules de CNT/5E2N. Ce résultat fait du mélange CNT/5E2N un agent auto-réparateur adapté pour une utilisation au sein de structures aérospatiales principales, ainsi qu’à l’intérieur de composants et de dispositifs électroniques avancés.

Self-healing polymers based on ring-opening metathesis polymerization (ROMP) incorporating second generation Hoveyda-Grubbs’ (HG2) catalyst as polymerization initiator and 5-ethylidene 2-norbornene (5E2N) as healing monomer are promising for self-healing applications. This is particularly true at low temperatures that may persist in the internal environment of an operating space vehicle. In this work, a detailed quantitative analysis of the ROMP reaction kinetics of 5E2N/HG2 system has been conducted from room temperature down to -30°C by using a systematic micro-Raman spectroscopy measurement. The analysis is based on measuring the changes in peak intensity and integrated area of Raman phonons related to the characteristic (C=C) functional groups indicating the progression of the reaction with time. The apparent rate constants for the reactions at different low temperatures were determined for the first order kinetics using the Arrhenius principle. The calculated values of the rate constants and activation energies are found consistent with values found in the literature for similar reactions. Our experiments and methodology were specifically designed to enable an efficient monitoring of the ROMP reaction below 0°C. This provides an opportunity for studying the effects of various factors on the polymerization kinetics of different self-healing system and optimizing them accordingly to make them suitable for specific applications. Considering the recent interest in the use of carbon nanotubes in advanced polymers for enhancing their structural and electrical performance, microencapsulation of carbon nanotubes in a self-healing monomer like 5E2N can open unique opportunities to impart electro-mechanical self-healing functionalities to the mechanical structures and electronic parts/devices used in modern aerospace vehicles. In our work, we successfully microencapsulated multiwalled carbon nanotubes (referred simply as CNTs in this work) suspended in 5E2N into polymeric shells using in-situ polymerization method. To ensure their suitability for self-healing applications, the thermo physical characteristics of the microcapsules, including their average size, shape, uniformity, shell wall structural integrity and thickness, thermal stability and core content are extensively investigated by optical and scanning electron microscopy as well as thermogravimetric (TGA) and differential scanning calorimetric (DSC) analyses. The presence of CNTs inside the core liquid content of the microcapsules, as well as their efficient release upon breaking event and the subsequent polymerization of the core monomers inside the damaged zone of the materials are confirmed by microscopy, spectroscopic and fractographic analyses Structural polymers like epoxy-based polymers are extensively used in various aerospace parts, structures, and devices. They, however, are subjected to various forms of damages under different loading conditions, which can accumulate over time leading to major structural failure. We report on a comparative investigation of the self-healing properties of epoxy-based polymer incorporated with microencapsulated CNT/5E2N under two different types of mechanical failure. Healing efficiencies of the epoxy systems incorporated with the two types of microencapsulated healing agents (5E2N and CNT/5E2N) were evaluated and compared under lap shear and mode I fracture loading. When implemented the microcapsules inside epoxy, we demonstrated that excellent self-healing capabilities incurred by the epoxy polymer under these two different loading modes within the system containing CNT/5E2N microcapsules. For both lap shear mode and mode I fracture tests, the use of CNT/5E2N suspension inside the core of the microvessels is found to improve the properties of the pristine composites, as well as their healing properties much better than the case of microcapsules containing only 5E2N. 97% of the fracture toughness and 78% of the lap shear strength is restored with microencapsulated CNT/5E2N after their complete mechanical failure compared to 76% and 39%, respectively, with microencapsulated 5E2N alone. Our results suggest that epoxies incorporated with CNT/5E2N microcapsules can serve both as very efficient self-healable matrix material for implementation in high performance laminated composites and self-healable structural adhesives in advanced aerospace engineering. When implemented inside conductive polymer, we also show that 82% of the electrical conductivity of the samples can also be autonomically restored using the CNT/5E2N microcapsules. This makes the CNT/5E2N healing agent suitable for self-healing applications for key aerospace structural parts as well as advanced electronic components and devices.


identifier: Wang, Kanghong  (2022). Solar-driven photoelectrochemical hydrogen generation based on colloidal core/shell quantum dots.  Thèse.  Québec, Doctorat en sciences de l'énergie et des matériaux, Université du Québec, Institut national de la recherche scientifique, 147 p.

subject:
PEC cell
quantum dots
core size effect
optical properties
alloyed shells
gradient band alignment
carrier transfer efficiency
charge recombination
theoretical calculation
core/multiple shell quantum dots
stability performance

abstract:
La transcription des symboles et des caractères spéciaux utilisés dans la version originale de ce résumé n’a pas été possible en raison de limitations techniques. La version correcte de ce résumé peut être lue en PDF.

Colloidal quantum dots (QDs) are considered as one of the promising candidates for next-generation solar-to-fuel energy conversion strategies due to many unique optical and
optoelectronic properties. Comparing to directly transferring to electricity, there is an
alternative to convert solar energy into hydrogen (H2) fuels. H2 is one of the green energy
resources with high power density and the by-product is only water. Thus, colloidal QDs have
been investigated a lot for photoelectrochemical (PEC) H2 generation. However, this strategy
still suffers from low solar-to-hydrogen (STH) efficiency as well as poor stability performance
which restrict their wider application. In my thesis, I used colloidal QDs as the solar harvester,
sensitizing TiO2 for PEC H2 evolution. The focus of my work is to design proper structure of
core/shell QDs to enhance the absorption from solar spectrum as well as facilitating the carrier
separation/transfer, leading to improved efficiency from solar energy to H2.
In my work, I first investigated the core size effect in CdSe/CdS core/shell QDs for PEC H2
generation. Generally, I synthesized four types of CdSe QDs with different size, varying from
2.8 nm to 4.8 nm in diameter by controlling the reaction time (2-10 min) under the same
temperature (260 ℃) via hot-injection approach. Afterwards, successive ionic layer adsorption
and reaction (SILAR) method was further applied to coat similar thickness of CdS shell by
controlling six monolayers, forming four types of CdSe/CdS core/shell QDs. Then transmission
electron spectroscopy (TEM) and X-ray diffraction (XRD) pattern reveal that all four CdSe/CdS
core/shell QDs were all ascribed to the same crystal structure with different size. In which the
CdSe is turning to wurtzite (WZ) crystal structure while CdS is zinc blende (ZB) crystal
structure. Also, the TEM images showed that the overall size of QDs is becoming larger with
longer reaction time. The ultraviolet-visible (UV-vis) absorption (Abs) and photoluminescence
(PL) spectra revealed that the position of the first-excitonic peaks vary from 585 nm to 635 nm
while the peaks in PL spectrum vary from 595 nm to 648 nm. Finally, when four types of
core/shell QDs were applied for PEC H2 generation, the saturated photocurrent density (Jph)
varied from 8.8 mA/cm2
to 17.4 mA/cm2
under one sun illumination (AM 1.5 G, 100 mW/cm2
).
The PEC results indicated that the core size has significate influence on the band alignment as well as the absorption range of core/shell QDs. In detail, the optimized PEC performance is
based on the QDs with core size of 3.5 nm which balanced the absorption range of QDs as well
as optimized carrier transfer efficiency.
In my second work, I investigated the composition effect of the CdS shell based on CdSe/CdS
core/shell QDs. Generally. I synthesized three types of core/shell QDs. The first one is
CdSe/CdS core/shell QDs with six monolayers of pure CdS shell. Then I engineered the shell
composition into CdSexS1-x alloyed shells. The two alloyed QDs are in the form of
CdSe/(CdSe0.5S0.5)4/(CdS)2 and CdSe/(CdSexS1-x)5/CdS which denoted as CdSe/Alloyed#1
QDs and CdSe/Alloyed#2 QDs, respectively. The difference between the two alloyed QDs is
the ratio of Se/S in each layer. When I applied the three types of core/shell QDs for PEC H2
generation, the Jph can reach 6.2 mA/cm2
for CdSe/CdS QDs. For alloyed QDs, the Jph can
achieve as high as 15.1 mA/cm2
and 17.5 mA/cm2
for CdSe/Alloyed#1 QDs and
CdSe/Alloyed#2 QDs, respectively. The dramatic improvement of PEC performance is mainly
because the alloyed layers can not only enhance the absorption but also increase the carrier
transfer efficiency by providing intermediate gradient layers. Thus, the unfavorable
recombination can be largely reduced.
Though the PEC performance is quite promising, the stability performance is not qualified for
long-term application. Based on this issue, in my third work, I concentrated on addressing the
issue of poor stability performance of QDs based photoanode. One important reason for poor
stability performance is the surface traps which will become the recombination center for
carriers. One of the strategies is to coat a wide-bandgap semiconductor to passivate the surface.
Based on this, I developed three types of QDs, CdSe/CdS core/shell QDs, CdSe/CdS/ZnS
core/multiple shell QDs and CdSe/CdSexS1-x/CdS/CdyZn1-yS/ZnS alloyed QDs. When I applied
three types of QDs for PEC H2 generation, the saturated photocurrent density can reach 12.6
mA/cm2
for CdSe/CdS core/shell QDs while 14.2 mA/cm2
for CdSe/CdS/ZnS core/multiple
shell QDs. For alloyed QDs, the saturated photocurrent density achieved unprecedent 20.5
mA/cm2
under one sun illumination (AM 1.5 G, 100 mW/cm2
). The PEC results indicated that
the ZnS shell can act as the protection and passivation shell for QDs, reducing the recombination events on the surface of QDs. Moreover, the alloyed intermediate layers can play
the role of reducing the energy barrier between the shells, increasing the charge transfer
efficiency accordingly. Then, I used three QDs for the stability measurement for two hours
under one sun power. For CdSe/CdS core/shell QDs based photoanode, only 55 % of the initial
current value was maintained for 2 hours. With the coating of ZnS shell, the CdSe/CdS/ZnS
core/multiple shell QDs based photoanode can maintain 84 % of the initial current value after
2 hours while the alloyed QDs based photoanode showed the best stability performance, 93.4 %
of the initial current value after 2-hour continuous illumination. This promising stability
performance of alloyed QDs based photoanode also can be attributed to the effect of ZnS shell
coating as well as the alloyed layers. Afterwards, I also investigated the impact of the shell
thickness of the ZnS. Among one to three monolayers of ZnS shell, two monolayers of ZnS
shell is proved to be the optimized shell thickness for PEC H2 generation. In other words, one
monolayer of ZnS is too thin to protect the QDs as well as passivate the surface of QDs while
three monolayers of ZnS is too thick which will reduce the charge transfer efficiency.


identifier: Tantawy, Anwar  (2022). Revisiting automatic speech recognition systems for augmentation capacity.  Thèse.  Québec, Doctorat en télécommunications, Université du Québec, Institut national de la recherche scientifique, 144 p.

subject:
modélisation acoustique
augmentation de données
auto-encodeur récurrent
transfert de style neuronal
acoustic modelling
data augmentation
recurrent autoencoder
neural style transfer

abstract:
Les applications de reconnaissance automatique de la parole (ASR) ont considérablement augmenté au cours de la dernière décennie en raison de l'émergence de nouveaux appareils et de matériel domotique qui peuvent grandement bénéficier de la possibilité pour les utilisateurs d'interagir les mains libres, tels que les montres intelligentes, les écouteurs, les traducteurs portables et les assistants domestiques. La mise en œuvre d'ASR pour ces applications souffre inévitablement d'une dégradation des performances dans les scénarios réels. La plupart des systèmes ASR s'attendent à ce que l'environnement de travail ressemble à l'environnement de formation, ce qui n'est souvent pas le cas, en particulier pour les nouvelles applications avec une disponibilité limitée des données. Cette étude vise à montrer expérimentalement l'effet des variations de l'environnement sur différents modèles ASR et la capacité de différents modèles à améliorer les performances lorsqu'ils sont fournis avec des données d'entraînement comme l'environnement de test. La prise en compte d'un certain type de variabilité se fait en modifiant ou en adaptant l'un des composants du système ASR, atténuant ainsi l'effet de la variabilité dans des scénarios réels. Cependant, cette approche nominale ne tient pas compte de toutes les variabilités possibles simultanément, mais au contraire pourrait entraîner une détérioration des performances par rapport à d'autres types de changements dans l'environnement de test. La plupart des succès récents en ASR dépendent principalement de l'abondance de données dans un certain domaine ainsi que de la capacité accrue des modèles d'apprentissage. Les performances de l'ASR diminuent alors avec la diminution de la quantité de données ou de la capacité du modèle. Par conséquent, ce travail propose différentes techniques d'augmentation de données et se concentre sur la capacité des différents modèles à s'améliorer avec différents types de données augmentées.

Automatic Speech Recognition (ASR) applications have increased greatly during the last decade due to the emergence of new devices and home automation hardware that can benefit greatly from allowing users to interact hands free, such as smart watches, earbuds, portable translators, and home assistants. ASR implementation for these applications inevitably suffers from performance degradation in real life scenarios. Most ASR systems expect the working environment to be like the training environment, which is often not the case, especially for new applications with limited data availability. This study is concerned with experimentally showing the effect of variations in the environment on different ASR models and the capacity of different models to improve performance when provided with training data like the testing environment. Taking a certain type of variability into account takes place by modifying or adapting one of the ASR system components, thus alleviating the effect of variability in real-life scenarios. However, this nominal approach does not account for all possible variabilities simultaneously, but on the contrary might result in deterioration in performance against other types of changes in the testing environment. Most of the recent successes in ASR are mainly dependent on the abundance of data in a certain domain along with the increased capacity of the learning models. The performance of ASR then decreases with the decrease of either the amount of data or model capacity. Hence, this work proposes different data augmentation techniques and focuses on the capacity of the different models to improve with different types of augmented data.


identifier: Zare, Fatemeh  (2022). Design and development of a new stimuli-responsive linker for biomedical applications.  Thèse.  Québec, Doctorat en sciences de l'énergie et des matériaux, Université du Québec, Institut national de la recherche scientifique, 255 p.

subject:
chimie du clic
lieur
bioconjugué
Clip chimie
thiol radicalaire
thioéther
sulfonium
méthionine
espèces réactives
click chemistry
linker
bioconjugate
Clip chemistry
radical thiol
thioether
sulfonium
methionine
reactive species

abstract:
Espèces réactives endogènes, y compris les espèces réactives de l'oxygène (ROS), les espèces réactives de l'azote (RNS) et les espèces réactives du soufre (RSS) sont en équilibre complexe les unes avec les autres et jouent un rôle vital dans les processus physiologiques. Cependant, la surexpression et la dérégulation de leurs équilibres dans le cadre de processus physiopathologiques conduisent à l'apparition et au développement de nombreuses maladies. Par conséquent, les liaisons chimiques qui répondent à ces stimuli biologiques sont importantes pour de nombreuses applications pharmaceutiques et biotechnologiques. Jusqu'à présent, diverses liaisons chimiques sensibles aux ROS, RNS et RSS ont été développées et appliquées pour des applications thérapeutiques, diagnostiques et théranostiques. Compte tenu de la diversité des applications envisagées pour de telles liaisons chimiques, il est pertinent d'explorer de nouvelles variantes avec des profils de réactivité différents de ceux actuellement trouvés dans la littérature. Ce travail présente une nouvelle liaison chimique, la liaison sulfure de vinyle sulfonium qui pourrait être installée sur des molécules de thioéther telles que des peptides contenant de la méthionine. La première partie de cette thèse a présenté les réactions et les facteurs impliqués dans la préparation de la liaison sulfure de vinyle sulfonium. Pour illustrer le potentiel de ces réactions, une alcyne déficiente en électrons a été installé de manière sélective sur le résidu méthionine de quatre peptides modèles et utilisée pour préparer une variété de bioconjugués par une réaction Click bien connue (addition nucléophile thiol-allène). Pour illustrer la polyvalence, une variété de bioconjugués ont été préparées (peptide-peptide; peptide-fluorophore; peptide polymère; peptide-protéine). Notre résultat a démontré que la liaison sulfure de vinyle sulfonium peut être préparée avec des réactifs/réactifs facilement accessibles et sans aucun intermédiaire destructeur. De plus, la liaison sulfure de vinyle sulfonium présentait le potentiel de la réaction Clip (addition radicale thiol-ène) en présence de radicaux thiols, ce qui induisait la libération complète des peptides d'origine via un processus de fragmentation simultané à la régénération de leur résidu méthionine non modifié (en minutes). Le résultat obtenu a démontré le potentiel de cette stratégie Click/Clip et du sulfure de vinyle sulfonium dans le secteur biotechnologique. La deuxième partie de cette thèse explore la réactivité d'une liaison de sulfure de vinyle sulfonium vis-à-vis des niveaux physiologiquement pertinents de différentes catégories d'espèces réactives et élucide la nature compétitive de ce processus dans les cellules. Les résultats indiquent que ces liaisons répondent aux thiols nucléophiles (heures/jours), aux radicaux thiols (minutes) et aux espèces azotées réactives (RNS; minutes) dans des conditions modèles conduisant à la libération d'un peptide contenant de la méthionine dans les deux premiers cas et à l’hydroxynitration dans le troisième cas. En présence de cellules et donc de concentrations biologiquement pertinentes de diverses espèces réactives, le RNS a surpassé les radicaux thiols pour la réaction avec le sulfure de vinyle sulfonium, tandis que la réaction avec les thiols nucléophiles restait attendue à des temps plus longs (heures/jours). Ce travail prépare donc le terrain pour l'utilisation prévisible de ces liens dans les secteurs biotechnologique et pharmaceutique.

Endogenous reactive species, including reactive oxygen species (ROS), reactive nitrogen species (RNS), and reactive sulfur species (RSS), are in complex equilibria with one another and play vital roles in physiological processes. However, their overexpression and the dysregulation of their equilibria under pathophysiological processes can lead to the onset and development of numerous diseases. Therefore, chemical linkages that respond to these biological stimuli are important for many pharmaceutical and biotechnological applications. Up to now, various ROS-, RNS-, and RSS-responsive chemical linkages have been developed and applied for therapeutic, diagnostic, and theranostic applications. Considering the diversity of applications foreseen for such chemical linkages, it is relevant to explore new variants with responsivity profiles that are different from those presently found in the literature. This work presents a new chemical linkage, the sulfonium vinyl sulfide group that can be installed on thioether molecules such as methionine-containing peptides. The first part of this thesis presents the reactions and factors involved in the preparation of sulfonium vinyl sulfide bond. To illustrate the potential of these reactions, an electron-deficient alkyne was conveniently and selectively installed on the methionine residue of four model peptides and used to prepare a variety of bioconjugates by a well-known Click reaction (nucleophilic thiol–allene addition). To illustrate versatility, a variety of bioconjugates were prepared (peptide–peptide; peptide– fluorophore; peptide–polymer; peptide–protein). Our results demonstrated that the sulfonium vinyl sulfide group can be prepared with readily accessible reactants/reagents and without significant side-reactions. Furthermore, the sulfonium vinyl sulfide groups exhibited the potential of Clip reaction (radical thiol–ene addition) in the presence of radical thiols, which induced the full release of the original peptides via a fragmentation process concurrent with the regeneration of their unmodified methionine residue (in minutes). The obtained results demonstrate the potential of this Click/Clip strategy and sulfonium vinyl sulfide in the biotechnological sector. The second part of this thesis explores the responsiveness of a sulfonium vinyl sulfide linker towards physiologically-relevant levels of different categories of reactive species and elucidates the competitive nature of this process in cells. Results indicate that these linkers respond to nucleophilic thiols (hours/days), radical thiols (minutes), and reactive nitrogen species (minutes) under model conditions leading to the release of a methionine-containing peptide in the first two cases and to hydroxynitration in the third case. In the presence of cells and hence biologically-relevant concentrations of various reactive species, RNS outcompeted radical thiols for reaction with the sulfonium vinyl sulfide, while reaction with nucleophilic thiols remained expected at longer times (hours/days). This work, therefore, sets the stage for predictably using such linkages in the biotechnological and pharmaceutical sectors.


identifier: Préskienis, Vilmantas  (2022). La forte variabilité des émissions de gaz à effet de serre des lacs et des mares de l’Arctique expliquée par la morphologie des plans d’eau, l’activité érosive et la qualité de la matière organique des sols environnants. / The high variability of greenhouse gas emissions from Arctic lakes and ponds explained by the morphology of water bodies, the erosional activity and the quality of organic matter in surrounding soils.  Thèse.  Québec, Doctorat en sciences de l'eau, Université du Québec, Institut national de la recherche scientifique, 186 p.

subject: CO2

subject: CH4

subject: lacs Arctiques

subject: mares de la toundra

subject: datation au 14C

subject: érosion thermique

subject: dégel du pergélisol

subject: biodégradabilité de la matière organique du sol

subject: expérience de biodégradabilité

subject: ébullition

subject: fonctionnement limnologique

subject: régime de mélange de colonne d’eau

subject: tendances saisonnières

subject: CO2

subject: CH4

subject: Arctic lakes

subject: tundra ponds

subject: 14C dating

subject: thermo-erosion

subject: permafrost thaw

subject: soil organic matter biodegradability

subject: biolability experiment

subject: ébullition

subject: limnological functioning

subject: mixing regime

subject: seasonal patterns

abstract:
La transcription des symboles et des caractères spéciaux utilisés dans la version originale de ce résumé n’a pas été possible en raison de limitations techniques. La version correcte de ce résumé peut être lue en PDF.

Les basses-terres de l'Arctique comptent un grand nombre de plans d'eau douce dont la genèse, la morphologie, le fonctionnement limnologique et la dynamique du carbone sont très variables. Ces écosystèmes aquatiques sont des points chauds de l'activité biogéochimique et des émetteurs importants de CO2 et de CH4 dans le paysage de la toundra. Bien que plusieurs études aient identifié leur rôle crucial dans le cycle global du carbone, les lacs et les mares de la toundra restent peu étudiés; leur fonctionnement et leur réponse potentielle aux changements climatiques ne sont pas bien définis. Dans cette thèse, nous avons étudié les variations à l'échelle locale des émissions de CO2 et de CH4 des lacs et des mares de la toundra de l'île de Bylot (archipel arctique canadien oriental, pergélisol continu) d'un point de vue géomorphologique. Nous avons mis l'accent sur la morphologie des plans d'eau, l'érosion des berges et la qualité de la matière organique du sol. L'étude présente des données recueillies sur le terrain et obtenues lors d'expériences en laboratoire. Les travaux sur le terrain comprenaient des mesures de flux gazeux émis par diffusion et ébullition, une analyse détaillée du fonctionnement limnologique des lacs et des mares, une cartographie précise du paysage mettant l’accent sur l'érosion des berges, et le carottage de la couche active et du pergélisol. Les échantillons des sols ont été utilisés pour caractériser la matière organique, et sa labilité a été évaluée par une série d'expériences en laboratoire. La morphologie des plans d'eau a joué un rôle important dans le contrôle de la saisonnalité des émissions de GES : les émissions maximales des lacs de thermokarst d’origine glaciaire et des mares polygonales coalescentes ont eu lieu au début du mois de juillet après la fonte des glaces, celles des mares en coin de glace à la fin du mois d'août au retournement automnal, tandis que le lac de thermokarst présentait des flux variables mais relativement élevés tout au long de la saison des eaux libres. Le lac de thermokarst a émis le carbone le plus ancien, mais les plus grands émetteurs par unité de surface étaient les mares en coin de glace. Ces mares présentaient un degré d'érosion des berges très variable, allant de berges stables couvertes de végétation aquatique à des berges extrêmement instables avec des blocs de sol riches en matières organiques qui tombent ou qui glissent vers l’eau. Les niveaux d'érosion étaient corrélés aux taux d'émission de GES, et les mares dont plus de 40% des berges étaient activement en érosion présentaient des flux significativement plus élevés que toutes les autres mares (4100 mmol CO2 eq. m-2 yr-1 , i.e. en moyenne 6 fois plus élevé que pour les autres). La signature isotopique des gaz indique que la couche active et les autres sources de carbone moderne ont été utilisées de manière prédominante, ce qui explique le jeune âge des GES émis. La matière érodée présentait des niveaux variables de labilité à la dégradation microbienne (passant d’un gain net de 7% à une perte nette de 18% du COD original sur une période de deux semaines). La respiration et le déclin du COD (comme proxy de la labilité) étaient généralement plus élevés pour la matière organique provenant de la couche active que celle provenant du pergélisol. Cette dernière présentait aussi une grande variabilité dans la labilité entre les sites de carottage, indiquant de grandes différences dans la mise en place du pergélisol et la diagenèse de la matière organique pendant l’Holocène. Les sols qui ont lixivié de la matière organique plus riche en acides gras saturées et d’origine végétale, ainsi que des molécules plus lourdes et plus aromatiques, semblent avoir été préférés par le microbiote d'une mare de coin de glace fortement en érosion. Les mares qui émettaient particulièrement plus de GES étaient entourés de sols qui libéraient davantage de nutriments par lixiviation. Le rapport C:N du sol, couramment utilisé comme caractéristique liée à la labilité de la matière organique du pergélisol, ne s’est pas avéré un bon indicateur de labilité. La variabilité observée ici sur un kilomètre carré de paysage de toundra souligne la nécessité d'études plus détaillées, alors que l'extrapolation sur de vastes zones à partir d'une poignée de mesures à l'échelle locale est encore très courante. Le verdissement de l'Arctique et l'intensification de l’érosion thermokarstique sont deux trajectoires plausibles causées par les changements climatiques; nos résultats indiquent que la première conduit à une augmentation des puits de CO2 mais à des émissions de CH4 plus élevées, tandis que la deuxième conduit à une augmentation des émissions des deux gaz. La détermination de la trajectoire prédominante d'un paysage donné sera essentielle pour évaluer le potentiel de réchauffement climatique causé par les émissions futures.

The symbols and special characters used in the original abstract could not be transcribed due to technical problems. Please use the PDF version to read the abstract.
Arctic lowlands feature a vast number of freshwater bodies highly variable in their genesis, morphology, limnological functioning, and carbon dynamics. These aquatic ecosystems are hotspots of biogeochemical activity and significant emitters of CO2 and CH4 on the tundra landscape. Although several studies have identified their crucial role on global carbon cycling, tundra lakes and ponds remain sparsely studied; their functioning and potential response to climate change is not well defined. In this thesis, we studied local-scale variations in CO2 and CH4 emissions from tundra lakes and ponds on Bylot Island (Eastern Canadian Arctic Archipelago, continuous permafrost) from a geomorphological perspective, with a special focus on water body morphology, shore erosion, and soil organic matter quality. The study presents data collected in the field and obtained during laboratory experiments. Field work included seasonal measurements of diffusive and ebullitive gas fluxes, detailed analyses of the limnological functioning of lakes and ponds, high-precision landscape mapping with a special focus on pond shore erosion features, and coring of active layer and permafrost. The collected soil samples were used to characterise organic matter, and its lability was assessed by series of laboratory experiments. Water body morphology played an important role in controlling the seasonality of GHG emissions: peak emissions for glacial thermokarst lakes and coalescent polygon ponds occurred early July during the ice melt; for ice-wedge trough ponds it was in late August, during autumnal mixing; whereas the thermokarst lake had fluctuating but relatively high fluxes throughout the open-water season. The thermokarst lake emitted the oldest carbon, but the largest emitters by surface area were the ice-wedge trough ponds. These ponds presented a wide range of shore erosion levels, from stable shores covered with aquatic vegetation to extremely unstable shores featuring falling or sliding blocks of organic-rich soil. Erosion levels correlated to GHG emission rates, and ponds with more than 40% of the shores actively eroding presented significantly higher fluxes than any other ponds (4100 mmol CO2 eq. m-2 yr-1 ; i.e., 6 times higher than in other studied systems). The gas isotope signature indicated that the active layer and other fresh-carbon sources were used predominantly, explaining the young age of emitted GHG. The eroded material presented variable levels of lability to microbial degradation (from 7% net gain to 18% net loss of original DOC over two weeks). DOC consumption and respiration rates (as proxies of lability) were generally higher from SOM from the active layer than that from permafrost. The characteristics of the latter were also more variable among coring sites indicating large differences of permafrost development and SOM diagenesis during the Holocene. Soils that leached OM richer in saturated, plant-based fatty acids, as well as heavier, more aromatic molecules, appeared to have been preferred by the microbiota of an actively eroding ice-wedge trough pond. Ponds presenting high GHG production were surrounded by soils which leached more nutrients. On the other hand, the bulk C:N ratio, commonly used as permafrost SOM lability characteristic, did not show strong relationships with organic matter lability. The variability observed here within one square kilometre of tundra landscape emphasises the need for more detailed studies, while extrapolations across vast areas from a handful of local-scale measurements is still too common. Both Arctic greening and thermokarst intensification are plausible trajectories under the observed climate change; our results indicate that the former leads to increased CO2 uptake but higher CH4 emissions, while the latter leads to increased emissions of both gases. Determining the predominant trajectory of any given landscape will be key to assessing the warming potential of future emissions.


identifier: St-Pierre, Brayden  (2022). A closer look at the relative timing and nature of gold mineralization of the BIF-associated Tiriganiaq deposit, Meliadine district, Rankin Inlet greenstone belt, Nunavut.  Mémoire.  Québec, Maîtrise en sciences de la terre, Université du Québec, Institut national de la recherche scientifique, 142 p.

subject: Archéen

subject: or

subject: or encaissé dans formations de fer rubanées

subject: gisement orogénique

subject: ceinture de roches vertes

subject: Nunavut

subject: Archean

subject: Gold

subject: BIF-hosted gold

subject: orogenic deposit

subject: Greenstone Belt

abstract:
La transcription des symboles et des caractères spéciaux utilisés dans la version originale de ce résumé n’a pas été possible en raison de limitations techniques. La version correcte de ce résumé peut être lue en PDF.

Le district aurifère de Meliadine est situé dans la ceinture de roches vertes archéennes polydéformées (environ 2660 Ma) de Rankin Inlet, au Nunavut. Le district comprend de nombreux gisements et zones aurifères d'intérêt qui sont spatialement associés à la faille Pyke et à des failles subsidiaires. Il s'agit notamment du gisement Tiriganiaq, actuellement en production, qui se trouve dans les turbidites dans le toit structural de la faille Lower, une structure est-ouest associée à la faille Pyke. Les "séries filoniennes" 1150 et 1250 du gisement de Tiriganiaq forment une série de zones minéralisées aux géométries complexes. De nouvelles relations sur le terrain démontrent que la minéralisation aurifère dans les filons 1150 et 1250 est contrôlée par d'étroites zones de cisaillement D2B inverses, à pendage nord, localisées dans un grauwacke à chlorite. Ces zones de cisaillement recoupent la foliation S2A légèrement plus abrupte, transposée et inclinée vers le nord, qui est de plan axial aux plis F2A transposés et serrés. Cette étude a également révélé l'importance des veines de quartz ± ankérite d'extension D2B, minéralisées, horizontales et à faible pendage vers le sud. Ces veines et les zones de remplacement des sulfures qui leur sont associées se développent de préférence dans des intervalles de formation de fer rubanée (FFR) au faciès d'oxyde-silicate et FFR pélitiques mineurs transposés et fortement plissés par les plis F2A. Les FFR au faciès oxyde-silicate et pélitique sont relativement enrichies en Au par rapport aux lithologies de grauwacke à chlorite et de mudstone laminé, ce qui signifie qu'elles ont agi comme piège chimique et structural pour la minéralisation aurifère. Dans l'ensemble, les altérations à séricite, ankérite idioblastique, quartz et chlorite sont présentes dans les lithologies sédimentaires clastiques (grauwacke à chlorite, mudstone stratifié et certaines parties de la FFR pélitique), tandis que la FFR à oxyde-silicate et certaines parties de la FFR pélitique comprennent un assemblage d'altération dominant à quartz ± chlorite ± ankérite ± sulfures. L'or a été introduit au plus tôt au cours de la déformation D2A, au plus tard au cours de la déformation syn- à tardi-D2B, et après le pic du métamorphisme. Le plissement et la formation de veines sont associés à la principale phase de déformation dans le secteur à l’étude, qui correspond à la deuxième phase (D2) de la déformation régionale. La déformation D2 du gisement de Tiriganiaq peut être subdivisée en deux phases principales continues: la première phase (D2A), est associée à un raccourcissement orienté nord-est‒sud-ouest et à un plissement F2A ; et la seconde phase (D2B), qui est associée à un raccourcissement nord-sud, à un plissement supplémentaire (F2B), ainsi qu'à un cisaillement inverse et à la formation de veines (veines d'extension à faible pendage sud et veines de cisaillement à pendage modéré vers le nord). Ces zones présentent certaines des teneurs en or les plus élevées du gisement Tiriganiaq et soulignent ainsi l'importance des successions de FFR transposées, cisaillées et plissées. Les plis F2A, plongent vers l'ouest et forment des zones à haute teneur contrôlées par la structure et la lithologie. Le gisement de Tiriganiaq présente des caractéristiques communes à d'autres gisements aurifères de classe mondiale encaissés par des FFR ou associés à des FFR, tels que Lupin, Meadowbank, Amaruq et Homestake (États-Unis), notamment le contrôle lithologique exercé par les FFR au faciès silicate ± oxyde sur l'or et les zones de forte déformation. L'exploration de minéralisations aurifères similaires dans la ceinture de roches vertes de Rankin Inlet devrait se concentrer sur les zones de charnières de plis des successions de FFR épaissies par la tectonique et fortement plissées, recoupées par des structures secondaires et/ou des zones de forte déformation.

The symbols and special characters used in the original abstract could not be transcribed due to technical problems. Please use the PDF version to read the abstract.

The Meliadine gold district is hosted within the Archean (ca. 2660 Ma) poly-deformed Rankin Inlet greenstone belt in Nunavut. The district comprises numerous gold deposits and prospects that are spatially associated with the Pyke Fault and its splays. This includes the currently producing Tiriganiaq deposit, which is hosted within the turbidite-dominated structural hanging wall of the Lower Fault, a west-trending splay of the Pyke Fault. The 1150 and 1250 “lode series” within the Tiriganiaq deposit are a series of ore zones with complex geometries. New field relationships demonstrate gold mineralization in the 1150 and 1250 lodes are controlled by narrow, north-dipping, D2B reverse-dextral shear zones localized within chloritic greywacke. These shear zones overprint the slightly steeper, transposed north dipping S2A foliation that is axial planar to transposed tight F2A folds. This study has also revealed the importance of horizontal to shallowly south-dipping ore-bearing D2B extensional quartz ± ankerite veins. These veins and their associated sulphide replacement zones are preferentially developed in transposed tightly F2A folded oxide-silicate facies BIF and minor pelitic BIF intervals. The oxide-silicate and pelitic BIF lithologies are relatively enriched in gold compared to the chloritic greywacke and the laminated mudstone lithologies signifying they acted as a chemical and structural trap for gold mineralization. Overall, sericite, idioblastic ankerite, quartz, and chlorite alteration are widespread in the clastic sedimentary lithologies (chloritic greywacke, laminated mudstone, and portions of the pelitic BIF) whereas the oxide-silicate BIF and portions of the pelitic BIF comprise a dominant quartz ± chlorite ± ankerite ± sulphides alteration assemblage. Gold was introduced earliest during D2A deformation, latest syn- to- late D2B deformation, and post-peak metamorphism. Folding and veining are associated with the main phase of deformation in the deposit area, which corresponds to the second phase (D2) of regional deformation. The D2 deformation at the Tiriganiaq deposit can be further subdivided into two main protracted phases: the first phase (D2A), which is associated with northeast-southwest-oriented shortening and F2A folding; and the second phase (D2B), which is associated with north-south shortening, further folding (F2B), and reverse shearing and veining (shallowly south-dipping extension veins and moderately north-dipping shear veins). These zones provide some of the highest gold grades within the Tiriganiaq deposit and thus highlight the importance of transposed west-plunging sheared and F2A folded BIF successions forming structurally and lithologically controlled high-grade zones. The Tiriganiaq deposit shows features common with other world-class BIF-hosted/associated gold deposits such as Lupin, Meadowbank, Amaruq, and Homestake (USA), notably the lithological control of silicate ± oxide facies BIF on gold and strong deformation zones. Exploration for similar gold mineralization within the Rankin Inlet greenstone belt should focus on areas with hinge zones of tectonically thickened tightly folded BIF successions, intersected by secondary structures and/or high-strain zones are highly prospective.


identifier: Shariatinik, Benyamin  (2022). Electrical resistivity tomography data assimilation using ensemble Kalman filter for heat tracing test: a case study in Quebec city, Quebec, Canada.  Thèse.  Québec, Doctorat en sciences de la terre, Université du Québec, Institut national de la recherche scientifique, 123 p.

subject: systèmes d’énergie géothermique

subject: expérience de traçage de la chaleur

subject: tomographie de résistivité électrique entre forages

subject: ensemble Kalman filtre

subject: conductivité hydraulique

subject: essais Iugeon

subject: suivi de la température

subject: geothermal energy systems

subject: heat-tracing experiment

subject: cross-borehole electrical resistivity tomography

subject: ensemble Kalman filter

subject: hydraulic conductivity

subject: slug test

subject: temperature monitoring

abstract:
Les systèmes d’énergie géothermique, comme les pompes à chaleur d’aquifère utilisent le sous-sol dans les zones urbaines comme sources d’énergie renouvelable. Il est nécessaire de caractériser les propriétés hydrauliques du sous-sol avant l’installation de tels systèmes. Dans ce contexte, un test d’injection de chaleur est une méthode reconnue qui peut aider à l’optimisation de la conception du système. Lors de ces tests d’injection de chaleur, le suivi peut être effectué avec des capteurs de température, des capteurs de pression d’eau et la tomographie de résistivité électrique (ERT) pour aider à caractériser les propriétés hydrogéologiques. Les outils de surveillance utilisés antérieurement comportent des lacunes comme des données de faible résolution et un lissage excessif, de sorte qu’ils ne peuvent pas reproduire l’hétérogénéité des propriétés hydrogéologiques. Les filtres de Kalman d’ensemble (EnKF) est un outil prometteur qui peut aider à surmonter le problème du lissage excessif pour évaluer l’hétérogénéité des propriétés hydrogéologiques. Ici, nous proposons une méthodologie pour assimiler les données d‘ERT dans un modèle numérique d’écoulement des eaux souterraines et de transfert de chaleur; où l’eau souterraine est extraite, et l’eau chauffée est réinjectée dans un aquifère de gravier sableux non confiné, soit un site expérimental situé à Québec au Canada. L’ensemble de données d’ERT contient 11 étapes temporelles. Nous avons évalué la qualité des données ERT en vérifiant la moyenne des variations de résistivité apparente mesurées au fil du temps et en effectuant une inversion électrique pour vérifier si elles contiennent des informations sur l’expérience d’injection de chaleur. Le modèle à éléments finis de l’écoulement des eaux souterraines et du transfert de chaleur développé avec FEFLOW 7.3 a été intégré à la relation pétro physique et à la modélisation électrique directe (Resipy) afin d’estimer les valeurs de résistivité électrique. Ensuite, la résistivité apparente estimée est assimilée pour mettre à jour le modèle de conductivité hydraulique en utilisant l’EnKF. Les résultats démontrent que l’approche proposée peut reproduire l’hétérogénéité de K puisque le modèle K mis à jour est raisonnablement conforme au logarithme lithologique. De plus, l’approche proposée a été en mesure de reproduire les mesures de température et de la ERT. La comparaison entre la distribution antérieure et postérieure de K avec ceux obtenus à partir d’essais lugeon montre que l’EnKF a fourni une distribution assimilée de K qui s’est déplacée vers des valeurs inférées avec les essais lugeon.

Geothermal Energy Systems such as groundwater heat pumps relying on aquifers uses renewable sources of energy that are accessible in urban areas. It is necessary to characterize the subsurface hydraulic properties prior to the installation of such systems. In this context, heat tracing experiments is a typical field test that can help with characterization of the subsurface. During a heat tracing experiment, monitoring with downhole temperature sensors, water-level pressure transducers and electrical resistivity tomography (ERT) can be used to characterize the hydrogeological properties. The mentioned monitoring tools contain shortcomings such as low resolution data and over-smoothing, which prevents them from correctly reproducing the heterogeneity of hydrogeological properties. Ensemble Kalman filter (EnKF) is a promising tool that can overcome the over-smoothing problem to replicate the hydrogeological property heterogeneity. Here, we proposed a workflow to assimilate time-lapse cross-borehole ERT data into a numerical model of groundwater flow and heat transfer. The workflow was tested in a heat tracing experiment where the groundwater was extracted and heated water was reinjected into an unconfined sandy-gravel aquifer located in Quebec City, Canada. The time-lapse cross borehole ERT surveys contained 11 time-steps. The quality of the monitoring cross-borehole ERT data was assessed by checking the mean value of apparent resistivity of each dataset overtime and also by performing electrical inversion to check if they contained information about heat tracing experiment. The finite element model of groundwater flow and heat transfer developed with FEFLOW 7.3 was integrated with petrophysical relationship and electrical forward modeling (Resipy) to estimate cross-borehole ERT measurements. Then, the estimated apparent resistivity was assimilated to update the hydraulic conductivity (K) model using EnKF. The results demonstrate that the proposed approach can reproduce the heterogeneity of K since the updated K model is reasonably consistent with the lithological log. In addition, the proposed approach was able to reproduce the cross-borehole ERT field and temperature measurements. The comparison between prior and posterior distribution of K with those obtained from slug tests shows that the EnKF provided an assimilated distribution of K that moved toward values inferred with slug tests.


title: Discovery of novel microbial natural products using a chemical screening approach and identification of gene clusters responsible for biosynthesis

type: Text Dissertation/Thesis

contributor: Kerr, Russell (Supervisory Committee Member)

contributor: Kirby, Chris (Supervisory Committee Member)

contributor: Fofana, Bourlaye (Supervisory Committee Member)

contributor: Haltli, Bradley (Supervisory Committee Member)

contributor: Kerr, Russell (Examination Committee Member)

contributor: Kirby, Chris (Examination Committee Member)

contributor: Linkletter, Barry (Examination Committee Member)

contributor: Ross, Avena (Examination Committee Member)

contributor: Hsiao, Amy (Examination Committee Member)

format: electronic 284 application/pdf

abstract:
Many of the pharmaceutical agents that are used clinically were developed from natural products and their derivatives. Natural products are often observed to have potent and specific interactions with biological targets, and are produced by a variety of macro and microorganisms. Actinomycetes have been an especially prolific source of natural products with antimicrobial applications and are responsible for approximately 70% of all clinically used agents. This has resulted in extensive investigation of these bacteria for the discovery of novel secondary metabolites, causing reisolation of known compounds to occur frequently. Novel techniques are needed to identify the production of new natural products to continue investigating natural sources for the discovery of new pharmaceutical agents.
To overcome the reisolation issue that hinders natural products discovery, a chemical based screening method was employed to prioritize strains for scale-up and further investigation. This method involved analyzing crude fermentation extracts using LC-HRMS, followed by principal component analysis to visualize the results. Utilization of this technique to analyze libraries of actinomycetes resulted in the identification of novel natural products more effectively than the tradition bioassay-guided method. This led to the selection of Streptomyces sp. RKKD-790 and Kitasatospora cystarginea NRRL B-16505 for further investigation.
A novel lasso peptide natural product tentatively named RKKD790_1592, was isolated from the fermentation broth of Streptomyces sp. RKKD-790. This group of peptides are characterized by their unique threaded structures, which provide them with superior stability compared to linear peptides. Computation modelling, MS/MS and stability assays were used to confirm that this novel peptide contained the characteristic threaded structure.
The strain K. cystarginea was found to produce three novel natural products, cystargamide, and cystargolides A and B. Unique structural features of cystargamide include the presence of the non-proteinogenic amino acids 4-hydroxyphenyl glycine and 5’-hydroxy typtophan and 2,3-epoxydecanoyl group. Cystargamide displayed the ability to activate production of pigmented metabolites by Streptomyces coelicolor in a disk diffusion assay. This interesting result indicated that cystargamide may be involved in bacterial communication, and may induce natural product biosynthesis in other bacteria. The gene cluster responsible for producing this novel lipopeptide was determined bioinformatically from the whole genome sequence of K. cystarginea. Cystargolides A and B are novel β-lactone containing peptides that were also produced by K. cystarginea. These peptides have very unique structures, and are the only natural products to have been described that contain a carboxyl and isopropyl substituted β-lactone group. Cystargolides A and B were found to be inhibitors of human 20S proteasome, showing that they are an excellent candidate for development as antiproliferating agents to treat cancer. Further investigations of these applications are ongoing by members of the Kerr group. The gene cluster involved in production of cystargolides A and B was predicted using bioinformatics and confirmed by generating a gene disruption mutant.
The discovery of these novel bioactive natural products represent exciting opportunities for development as an inducer of bacterial natural products, and an anticancer agent. Members of the Kerr group are continuing to explore these interesting applications. Identification of their unique structures and biosynthesis also extend our knowledge of the natural product production capabilities of bacteria.


title: Virgin, bride and lover [microform]

creator:
, (Thesis advisor)
(Degree grantor)
, (Committee member)

publisher: Memorial University of Newfoundland, 1992

subject: Specific Literature: English literature--Time Period: 1100-1499 Middle English period--Literary Theme: (treatment of) female sexuality--female spirituality--(relationship to) human body

abstract: The spirituality portrayed in AncreneWisse and the texts associated with it is rooted in the anchoress' own situation: a female solitary enclosed within the four walls of her anchorhouse. The images used to express that spirituality are tied to her experience of enclosure and to her gender. These two elements come together in the matrix of anchorhouse/body/heart, in which the anchoress' female body becomes identified with the anchorhouse in which it is enclosed. The spirituality of these texts is thus deeply grounded in the anchoress' sexuality and her perception of her own body. The images of enclosure and female sexuality which dominate these texts are expressed in terms of the paradox of the virgin who is at the same time the lover and bride of Christ. The female body enclosed within the anchorhouse is sealed by physical chastity, just as the anchoress is sealed within her anchorhouse. Physical purity is itself an image or symbol of the purity of heart and soul which is an essential prerequisite for theanchoress' goal of union with God. It is for this, and this alone, that she has turned from the world and enclosed her body and heart in the confines of her anchorhouse. The union with God which the anchoress seeks is also described in images which are governed by both her enclosure and her gender. The spiritual quest of the anchoress is unequivocally the search of a female devotee for a male God, who approaches her in very human terms. The enclosed chamber of her heart which she prepares for his coming is the arbour or bower in which she greets her beloved, and the nest or womb in which she nurtures her God. Her union with God is described in terms both sensual and sensuous, combining erotic imagery with imagery of motherhood and fertility. The erotic union with Christ available to the anchoress in her enclosure transforms and redeems, as the body which is vulnerable to lust (her own and other's) becomes the vessel which bears Christ through imitation and union.

abstract: 5 microfiches. University Microfilms order no. UMI00427865


title: Exploring the “Third Space” experiences of students with SEBD within outdoors and online contexts

contributor:
Fovet, Frederic (author)
(Thesis advisor)
(Supervisory Committee Member)
(Examination Committee Member)

format: electronic application/pdf


title: Pursuit and persistence in science career pathways

publisher: National Library of Canada = Bibliothèque nationale du Canada


title: Environmental education for nature connection: An animist arts-based exploration

contributor: McAuley, Sandy (Supervisory Committee Member)

contributor: Walton, Fiona (Supervisory Committee Member)

contributor: McAuley, Sandy (Examination Committee Member)

contributor: Walton, Fiona (Examination Committee Member)

contributor: Moffatt, Lyndsay (Examination Committee Member)

contributor: Jordan, Nane (Examination Committee Member)

format: electronic 95 application/pdf

abstract:
Caring for the community of life on planet Earth is critical for human survival. Humans
that have a higher degree of nature connectedness demonstrate care for other humans and
other-than-human life. Environmental educators frequently deliver programming meant
to improve nature connectedness. The programs assessed so far demonstrate that
environmental education programming creates a questionable impact on participant
nature connectedness. To help improve the effectiveness of nature connection
programming, I attempted to develop an animist ontological perspective, and experienced
a solitary 40-day environmental education program. It was a phenomenological inquiry
into the nature and process of nature connection. I represented the phenomenon in
collaboration with other artisans to create an evocative trigger for educators to reflect
upon and critically examine current methods. It is possible that connectedness is better
represented as shedding a false dualist meta-narrative, as opposed to connecting “self”
and “nature”, or even building a relationship with other-than-human life. It is possible
that revealing the unity of life by deconstructing human/nature dualism may be
effectively implemented as environmental education programs by (i) re-naming and unnaming
the world, and (ii) art-based self-renunciation.
Keywords: environmental education, nature connection, animism, art-based
research, post-structural feminism, deconstruction, decolonization, un-naming, art-based
self-renunciation


title: Exploring the expansion, impact and a control option for European green crab populations in Prince Edward Island, Atlantic Canada

contributor: Quijon, Pedro (Supervisory Committee Member)

contributor: St-Hilaire, Sophie (Supervisory Committee Member)

contributor: Landry, Thomas (Supervisory Committee Member)

contributor: McNiven, Mary (Supervisory Committee Member)

contributor: Davidson, Jeff (Supervisory Committee Member)

contributor: Quijon, Pedro (Examination Committee Member)

contributor: McKenzie, Cynthia (Examination Committee Member)

contributor: Greenwood, Spencer (Examination Committee Member)

contributor: Landry, Thomas (Examination Committee Member)

format: electronic 186 application/pdf

abstract:
One of the world’s most successful marine invaders, the European green crab (Carcinus
maenas), continues to spread and invade the coastlines of Atlantic Canada. In Prince Edward
Island in particular, populations have continued to expand since the late 1990s. In areas like these,
there is a distinct need to document this species’ expansion into new habitats, to monitor its
impacts on important native species, and to develop innovative mitigation strategies to control
some of its effects. This thesis addressed the large information gap that still exists on this species’
effect in the Atlantic Canadian region by focusing on four main areas: First, I explored over a
decade of green crab population expansion records along Prince Edward Island’s main shorelines.
Second, I surveyed and examined the effects of green crabs on vulnerable size classes of an
important shellfish species, the American oyster (Crassostrea virginica). Third, I performed a
preliminary study into the occurrence and synchrony of molting in green crabs, identifying
suitable physical features of pre-molting crabs as a first step for developing a soft-shell crab
industry. And fourth, I developed and tested a novel bycatch reduction device to be used with
fyke nets to facilitate the implementation of the aforementioned directed fishery for this species.
Samples collected during the years 2000-2013 indicated that green crab expansion rates
on Prince Edward Island vary spatially and temporarily. Expansion rates were higher along the
south shore than the north shore of the island, and it was hypothesized that this dissimilarity was
possibly related to the higher availability of suitable habitat along the south shore. The speed of
the spread was such that it seemed more likely related to the benthic movement of juvenile and
adult crabs than associated to larval spread or new anthropogenic vectors. With regards to green
crab impacts, multiple oyster bed surveys conducted in 2014 measured mortality levels of
vulnerable size classes of oysters. These surveys revealed that the probability of mortality of
small oysters was higher in areas where green crabs were present. This probability decreased in
the presence of other food sources (i.e. mussel beds), a result likely linked to green crab prey preferences. Field experiments using inclusion/exclusion cages indicated that the odds of oyster
mortality was higher in inclusion cages than in the open environment and exclusion cages. These
results suggested that at least some of the mortality of oysters could be attributed to green crab
predation.
With the recent implementation of a fishery for green crab as a potential mitigation
strategy, there is a need for a marketable product to prompt fishermen to harvest green crabs. A
soft-shell green crab product modelled after the Venetian “moleche” is expected to provide a
lucrative incentive beyond the existing hard shell bait market. The examination of the timing and
characteristics of molting revealed that synchronized “molting windows” or times of increased
molting occur in the early summer for male green crabs. Recorded molting rates in the laboratory
and the field were as high as 75% and 60%, respectively. External physical characteristics such as
the presence of a “halo” on the episternites of the carapace, were deemed a reliable indicator that
a crab would molt within 3 weeks. Although these results were preliminary in nature, they were
promising and suggested that further studies be performed on the potential scaling up of these
results. Fyke nets are a natural choice for a directed fishery of green crabs, as this type of gear is
readily available and used locally, primarily for American eel (Anguilla rostrata). These nets are
also a variant of the fyke net used in Italy to fish for a similar species of crab (Carcinus aestuarii)
during its molting season. However, before fyke nets can be used in a directed fishery for green
crab in Atlantic Canada, bycatch must be reduced. A novel Bycatch Reduction Device (BRD) for
fyke nets was therefore developed and evaluated. Bycatch numbers and diversity, including three
key commercial species, were significantly lower in the BRD equipped nets.
Overall, the results of this thesis advance green crab research in the region, especially
with regards to the quantification of impacts and development of mitigation measures. Further
research questions as a result of my thesis work are identified and briefly discussed.


title: Exploration of the antimicrobial and magnetic properties of  ƞ⁶-arene-ƞ⁵-cyclopentadienyliron(ll)-derived dendrimers

contributor: Abd-El-Aziz, Alaa (Supervisory Committee Member)

contributor: Etkin, Nola (Supervisory Committee Member)

contributor: Linkletter, Barry (Supervisory Committee Member)

contributor: MacQuarrie, Stephanie (Supervisory Committee Member)

contributor: Saleh, Tarek (Supervisory Committee Member)

contributor: Abd-El-Aziz, Alaa (Examination Committee Member)

contributor: Etkin, Nola (Examination Committee Member)

contributor: Linkletter, Barry (Examination Committee Member)

contributor: Ahmadi, Ali (Examination Committee Member)

contributor: Foucher, Daniel (Examination Committee Member)

contributor: Hsiao, Amy (Examination Committee Member)

format: electronic 175 application/pdf

abstract:
This thesis reports a new family of cationic organometallic dendrimers as an antimicrobial
platform and a magnetoceramic precursor. The synthesis of these dendrimers involved well-established
chemistries, especially the facile nucleophilic aromatic substitution (SNAr) reaction of
ƞ⁶-arene-ƞ⁵-cyclopentadienyliron(ll) ([ƞ⁶-chloroarene-ƞ⁵-CpFe]+) complex with a phenolic
nucleophile. The use of [ƞ⁶-chloroarene-ƞ⁵-CpFe]+ resulted in iron-containing dendrimers that
undergo SNAr reaction with nucleophilic functional molecules to give bifunctional dendrimers,
and also have implications for antimicrobial activity and ferromagnetism. Indeed, the dendrimers
yielded bifunctional, photoactive and redox-active, as well as dual-emissive dendrimers.
Importantly, the dendrimers were active against drug-resistant bacteria, including methicillinresistant
Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecium. The
activity depends on the nature of the counteranion because changing from BF4
- to PF6
-
counteranion enhanced activity. Also, the dendrimers induced oxidative stress on MRSA and
disrupted the microbial cell membrane. Functionalization of the dendrimers with known
antimicrobial agents, quaternary ammonium groups or 2-mercaptobenzothiazole, yielded hybrid
antimicrobial dendrimers with enhanced activity, especially at higher generation. On pyrolysis at
900 °C in an inert atmosphere, these dendrimers yielded ceramics with room temperature, soft
ferromagnetism. The magnetism was tuned via dendritic effects or functionalization with cobalt.
Indeed, saturation magnetization (Ms) and coercivity (Hc) decreased with increase in dendrimer
generation. Incorporating Co increased Ms and Hc at the second-generation but decreased these
properties at the zeroth- and first-generations. Overall, [ƞ⁶-chloroarene-ƞ⁵-CpFe]+ -derived
dendrimers are a versatile platform for accessing functional, in particular antimicrobial and
magnetic, materials.


identifier: Reference Identifier: 5299 ISSN/ISBN: 0612383466

title: From the Twilight to the Ecstasy: The Death and Life of 'Rita Joe'

title: Dissertation Abstracts International: Section A: The Humanities and Social Sciences University of New Brunswick, 1998 Ottawa, National Library of Canada = Bibliotheque nationale du Canada, [1999]

subject: Specific Literature: Canadian literature

subject: Time Period: 1900-1999

subject: Subject Author: Ryga, George (1932- )

subject: Subject Work: The Ecstasy of Rita Joe (1967)

subject: Literary Genre: drama

subject: English

abstract: From the Twilight to the Ecstasy: The Death and Life of Rita Joe" is a scholarly edition of George Ryga's play 'The Ecstasy of Rita Joe '. It combines and employs the editorial practices of D. H. Reiman and Jerome J. McGann in order both to explore the play's creation and to present clearly the disorderly history of this text. The manuscripts of the play are divided into two sections: the manuscript [MS] versions, which represent the early drafts, and the performance [PF] versions, which are the production drafts. Reiman's theory of textual versioning is deployed to represent the four MS versions of the play. Each discrete version is presented with supplementary notes. For the NIS versions, my editorial methodology privileges authorial intent. However, McGann's theory of the socialized text guides the presentation of the PF versions, in which a more communal authorial process develops. This version is eclectic, using a single copytext supplemented with variants from the PF versions. The annotated texts of the play are accompanied by three essays. The textual essay describes and addresses the peculiar textual problems involved with the project, and introduces and contextualizes the rationale behind the editorial methodologies chosen. The biocritical essay examines areas of Ryga's life relevant to a deeper understanding of the play's genesis. The critical essay introduces a new reading of the play as an example of Canadian agitprop. This project is intended to provide Ryga scholars with access to the information in the manuscripts. As well, a reader of this dissertation will be able to follow the play's creative path. Critics will benefit from the clear presentation of the variants; dramaturges will appreciate the theatrical contextualization of the canonical piece. Uninitiated readers may be surprised at how the play changed under the single influence of Ryga compared with the collaborative influence of the rehearsal hall.


title: The role of Sox4 in kidney development

contributor: Kamunde, Collins (Supervisory Committee Member)

contributor: Hartwig, Sunny (Supervisory Committee Member)

contributor: Wright, Glenda (Supervisory Committee Member)

contributor: Greenwood, Spencer (Supervisory Committee Member)

contributor: Martinson, Shannon (Supervisory Committee Member)

contributor: Spears, Jonathan (Supervisory Committee Member)

contributor: Bate, Luis (Examination Committee Member)

contributor: Hartwig, Sunny (Examination Committee Member)

contributor: Martinson, Shannon (Examination Committee Member)

contributor: McConkey, Sandra (Examination Committee Member)

contributor: Bridgewater, Darren (Examination Committee Member)

format: electronic 152 application/pdf

abstract:
Over the last decade the number of Canadians with end-stage kidney disease (ESKD)
has steadily risen and there are at present more than 35,000 Canadians living with
ESKD. Currently only three treatment options are available to replace the blood filtering
function performed by the kidneys: hemodialysis, peritoneal dialysis and kidney
transplant. A better understanding of the mechanisms involved in kidney development
could hold the key to developing targeted therapies to repair and reverse damage caused
by kidney diseases.
The DNA-binding transcription factor Wilms' Tumor Suppressor-1 (WT1) plays an
essential role in nephron progenitor cell differentiation during kidney development. In
mice, homozygous deletion of Wt1 results in complete absence of both kidneys.
Previously, chromatin-immunoprecipitation coupled to microarray identified all three
members of the Sry-related high-mobility group (HMG) Box (Sox)C subfamily, namely,
Sox4, Sox11 and Sox12, as novel Wt1 target genes that may regulate kidney
development in vivo. Although SoxC genes play master roles in determining neuronal
and mesenchymal progenitor cell fate in a multitude of developmental processes, their
function in the developing kidney has been, until now, undefined.
All three SoxC genes are expressed in the nephrogenic lineages during kidney
development. Conditional ablation of Sox4 in nephron progenitors and their cellular
descendants (Sox4neprhon- mice) results in early-onset proteinaceous glomerular injury
within 2 weeks of birth progressing to end-stage renal failure within 5-9 months. An updated version of the gold standard modality to accurately, rapidly and cost-effectively
quantitates nephron number in embryonic and post-natal mouse kidneys was developed.
This approach was used to determine that ablation of Sox4 in nephron progenitors and
their cellular descendants results in a significant reduction in nephron endowment.
This reduction in nephron endowment in Sox4neprhon- mice results from the formation of
fewer pretubular aggregates, likely as a result of decreased cell cycling of nephron
progenitor cells. Sox4 and Sox11 were also shown to be dispensable for normal podocyte
differentiation and function. Conditional deletion of both of these genes individually as
well as in combination in podocytes resulted in no apparent glomerular phenotype after 6
months and does not recapitulate the phenotype observed in Sox4neprhon- kidneys. Analysis
of Sox4neprhon- kidneys suggests that the genesis of glomerular injury may be activated
parietal epithelial cells (aPEC).
Collectively, the results presented in this thesis demonstrate that Sox4 plays multiple
crucial roles in normal kidney development and function in vivo.


title: Assessing the efficacy and side effects of lidocaine used as an analgesic on rainbow trout (Oncorhynchus mykiss)

contributor: Bate, Luis (Supervisory Committee Member)

contributor: Stevens, Don (Supervisory Committee Member)

contributor: Creighton, Cate (Supervisory Committee Member)

contributor: Greenwood, Spencer (Examination Committee Member)

contributor: Wright, Glenda (Examination Committee Member)

contributor: Stevens, Don (Examination Committee Member)

contributor: Creighton, Cate (Examination Committee Member)

format: electronic 215 application/pdf

abstract:
It has been said that “in many animals, the most simple and elegant way to
control pain perioperatively is to perform a local or regional anesthetic block” (1). The
experiments outlined in my thesis aimed to show whether or not fish can be counted
among those animals. Fish are proving to be a useful animal for many types of
research. Unfortunately, their increased popularity in recent years has not been
accompanied by an important improvement of our understanding of their welfare. There
is ongoing debate about whether or not fish can consciously feel pain even though it is
agreed that they can perceive and respond to noxious stimuli. They are regularly
exposed to such stimuli through various procedures related to research, yet analgesics
are rarely used(2). This is why I evaluated lidocaine, a local anesthetic widely used in
humans and other species, as a potential addition to current anesthetic protocols for
fish. I started by looking at potential side effects of the infiltration of a high dose of
lidocaine (20 mg/kg) on each side of the dorsal fin of young rainbow trout (15 fish per
group) as compared to infiltration with an equal volume of saline in the same locations
or anesthesia only. The fish were housed individually for the trial during which they were
observed and recorded for 4h after infiltration and fed at 6 different time points (15 min,
30 min, 1h, 2h, 3h, 4h). Their behavior was then analyzed using tracking software and
potential tissue lesions were assessed by histopathology of the infiltration site.
Ventilation rate was recorded using the remote function of GoPro cameras placed on
the side of each trial tank. Another experiment aiming to establish a beneficial dose
range for the infiltration of lidocaine repeated this procedure while adding a noxious stimulus in the form a small metal spring on the dorsal fin and testing doses of 2 mg/kg,
6 mg/kg, 20 mg/kg and 60 mg/kg.
My results show some potentially beneficial effects of lidocaine at a dose of 20
mg/kg when used as a local anesthetic for rainbow trout, such as increased food
consumption and ventilation rate closer to usual reported range compared with the other
groups. There was degeneration and inflammation in the muscle at the site of lidocaine
infiltration for the first 15 days post-infiltration but the infiltration sites were mostly healed
at 30 days post-infiltration. This study introduced a new model to test local anesthetics
and potentially other analgesics. This model appears promising to test local anesthetics
and potentially other analgesics, but should be refined before being used in the future.
Further studies are needed to find an optimal analgesic dose, as no clear conclusions
could be reached based on my data.


identifier: Reference Identifier: 3280 ISSN/ISBN: 0612415600

title: Sur les traces de Balzac: L'Exc?s dans les nouvelles philosophiques [microforme]

title: University of Toronto, 1997 Ottawa : National Library of Canada = Biblioth?que nationale du Canada, [2000]

subject: Specific Literature: French literature

subject: Time Period: 1800-1899

subject: Subject Author: Balzac, Honor? de (1799-1850)

subject: Subject Work: Etudes philosophiques

subject: Literary Genre: short story

subject: Literary Theme: (treatment of) excess

subject: Modern Languages

abstract: Balzac has long been associated with excess, both personal and literary, whether it be his abundant literary output, his effort to depict all aspects of nineteenth-century French society, his commercial ambitions which inevitably ended in failure, or the minute descriptions which characterize his novels in particular. Balzac's short stories have received considerably less critical scrutiny, and yet their very economy serves to highlight a certain mechanism of excess all the more clearly. The short stories of the 'Etudes philosopbiques ' seem to be an especially fertile corpus for examining the notion of excess, given that they portray for the most part protagonists whose obsessive desire causes them to go to excessive lengths to bring it to realization, an excess which inevitably takes the form of an appropriation of the other, an imposition of the subject's will on another character. This first excessive "moment" or phase can also be conceived in linguistic terms, as an attempt by the subject to impose hisdesire (a signified) on a form (or signifier) which, as "other", is resistant to this reduction of its polysemy. The figurative language of Balzac's texts thus show traces of this violent impact or collision between signifier and signified, traces which take the form of an allegory telling the story of the impossibility of the adequation between subject and other, meaning and form, realization and enunciation. This second excessive moment would thus have a metareferential function. And yet, despite the inexorable failure of the protagonists' respective quests, Balzac's texts steadfastly resist simplistic nihilit readings, in that they consistently propose a mediating figure capable of "reading" the other, respecting the latter's alterity, the primordial difference between form and meaning. In this sense, it is possible to locate in the figurative dimension of these texts an ethical component.


title: Social feedback

abstract: Information seeking on the Web has become a central part of many daily activities. Even though information seeking is extremely common, there are many times when these tasks are unsuccessful, because the information found is less than ideal or the task could have been completed more efficiently. In unsuccessful information-seeking tasks, there are often other people who have knowledge or experience that could help improve task success. However, information seekers do not typically look for help from others, because tasks can often be completed alone (even if inefficiently). One of the problems is that web tools provide people with few opportunities to learn from one another’s experiences in ways that would allow them to improve their success.  This dissertation presents the idea of social feedback. Social feedback is based on the theory of social learning, which describes how people learn from observing others. In social feedback, observational learning is enabled through the mechanism of interaction history – the traces of activity people create as they interact with the Web. Social feedback systems collect and display interaction history to allow information seekers to learn how to complete their tasks more successfully by observing how other people have behaved in similar situations.  The dissertation outlines the design of two social-feedback systems, and describes two studies that demonstrate the real world applicability and feasibility of the idea. The first system supports global learning, by allowing people to learn new search skills and techniques that improve information seeking success in many different tasks. The second system supports local learning, in which people learn how to accomplish specific tasks more effectively and more efficiently. Two further studies are conducted to explore potential real-world challenges to the successful deployment of social feedback systems, such as the privacy concerns associated with the collection and sharing of interaction history. These studies show that social feedback systems can be deployed successfully for supporting real world information seeking tasks. Overall, this research shows that social feedback is a valuable new idea for the social use of information systems, an idea that allows people to learn from one another’s experiences and improve their success in many common real-world tasks


title: Mechanisms for pesticide-induced cardiotoxicity in fish: An electrophysiological study using the zebrafish (Danio rerio) as a model

contributor: Côté, Etienne (Supervisory Committee Member)

contributor: Gilmour, Robert (Supervisory Committee Member)

contributor: Hamilton, Stephanie (Supervisory Committee Member)

contributor: Creighton, Catherine (Supervisory Committee Member)

contributor: Van Den Heuvel, Michael (Supervisory Committee Member)

contributor: Gelens, Hans (Examination Committee Member)

contributor: Gilmour, Robert (Examination Committee Member)

contributor: Arai, Shiori (Examination Committee Member)

contributor: Doucette, Tracy (Examination Committee Member)

format: electronic 118 application/pdf

abstract:
Fish kills are a common phenomenon in Prince Edward Island (Canada) and their cause often remains unexplained. I hypothesized that fish exposure to selected environmental toxicants leads to increased mortality and morbidity by depressing cardiac function, precipitated by suppression of cardiac electrical activity and rhythm disturbances. These rhythm disturbances could result from toxicant-induced changes in the function of specific cardiac ion channels. Recently, the zebrafish heart has been shown to hold promise as a suitable model to study cardiac cellular electrophysiology. The purpose of the present study was to
evaluate the effects of selected environmental toxicants on cardiac action potential morphology. More specifically, the present work focused on evaluating the effects on atrial action potential in adult zebrafish of: 1) acetylcholine (1-10 μM); 2) a documented acetylcholinesterase inhibitor, physostigmine (50 μM); 3) pesticides with acetylcholinesterase inhibition properties that are commonly used in Prince Edward Island (mancozeb and phorate). Zebrafish hearts were isolated under anesthesia and
action potentials were recorded in vitro using a standard single microelectrode technique. Action potential morphology was then assessed by measuring parameters including action potential duration (APD) and action potential amplitude (APA). Results revealed that in vitro exposures to high concentrations of acetylcholine
and physostigmine led to suppression of cardiac electrical activity by significantly reducing APD and APA, a phenomenon known as cholinergic non-excitability. Experiments evaluating the effects of commercial pesticides (mancozeb and phorate) did not reveal similar effects. This study supports the possibility that environmental toxicants containing acetylcholinesterase inhibitors may participate in fish kills by suppressing cardiac electrical activity. However, the specific pesticides mancozeb and phorate did not demonstrate such dramatic cardiotoxic effects, even at high concentrations.