Architecture d'un processeur dédié aux traitements de signaux ultrasoniques en temps réel en vue d'une intégration sur puce

RÉSUMÉ Cette thèse se rapporte à la conception d’une nouvelle architecture d’un système d’appareils d’imagerie médicale par ultrasons (IMU); nous proposons une architecture matérielle d’un processeur dédié au prétraitement de signaux ultrasoniques en temps réel, qui intègre un cœur (core) de traitement, un module d’interpolation et un module d’assignation de priorités qui permet de partager le bus de données d’une mémoire à faible consommation d’énergie. Ce processeur dédié représente une contribution importante aux efforts visant à l’intégration complète d’un système de prétraitement de signaux ultrasoniques à l’intérieur d’une sonde qui fait partie des appareillages ultrasoniques conventionnels ainsi qu’à la mise en œuvre d’un nouveau type d’appareil d’IMU sans fil. La littérature des deux dernières décennies présente diverses approches visant à miniaturiser la technologie de l’IMU. Plusieurs auteurs proposent des solutions en matière d’intégration des circuits frontaux ou de matérialisation de nouveaux algorithmes de traitement des signaux ultrasoniques. Les efforts de recherche dans ce domaine sont propulsés par l’intérêt grandissant des marchés et par le développement de nouvelles applications qui bénéficient de la miniaturisation de cette technologie. De plus, les performances grandissantes des circuits intégrés programmables tels que les FPGA offrent les caractéristiques appropriées pour la mise en œuvre de nouveaux systèmes d’IMU.----------ABSTRACT This Ph.D. thesis is related to the design of a new architecture of ultrasound medical imaging (UMI) system. We propose a fully hardware-based processor dedicated to real-time ultrasonic signal processing, which incorporates a preprocessing core, a low-power memory, an interpolation unit, and a priority assignment unit. This Ph.D. thesis represents an important contribution towards the complete integration of an ultrasound preprocessing system within the probe and the implementation of a new type of wireless UMI device. During the last two decades, several UMI system miniaturization approaches have been presented in the literature. Some Authors proposed their front-end circuit integration and introduced hardware-based ultrasound signal processing units based on new algorithms. Research efforts in this area are driven by the increasing industrial interest on miniaturized UMI devices and by the development of new applications that benefit from the miniaturization of this technology. Moreover, the increasing performance of programmable circuits, such as FPGA, offers appropriate characteristics for the implementation of new UMI systems. Most UMI system architectures found in the literature are based in whole or in part on a software implementation that uses a central processing unit (CPU) or a digital signal processor (DSP). This software approach provides flexibility and facilitates the implementation of processing algorithms which are becoming ever more effective and complex. However, to provide real-time ultrasound image processing, these systems require high-power consumption or are too large for a complete system integration on a single chip (SoC)

Conception d'un montage de caractérisation des propriétés mécaniques de vaisseaux reconstruits par génie tissulaire

Le génie tissulaire vise à remplacer, réparer ou reproduire un organe ou un tissu pour des fins de chirurgie reconstructive ou de remplacement et pour servir de modèle d’étude et de recherche. Les substituts vasculaires produits par génie tissulaire peuvent être partiellement caractérisés en mesurant certaines de leurs propriétés mécaniques telles que la pression d’éclatement et la compliance et en les soumettant à des essais de fatigue et de fluage. La mesure des ces caractéristiques permet de vérifier que la méthode de fabrication produit des substituts vasculaires présentant des caractéristiques d’ordre physiologique. Un système permettant la mesure de ces propriétés mécaniques de manière fiable, précise et répétitive a été conçu et fabriqué. Ce système contrôlé par ordinateur soumet les substituts à des pressions hydrodynamiques dont les valeurs sont enregistrées de façon synchronisée avec les mesures de diamètre du substitut. L’analyse des données produites permet de calculer les propriétés mécaniques d’intérêts.Tissue engineering presents a promising approach for producing tissues to replace, repair or reproduce tissues and organs to be used for reconstructive surgery or as a research model. Tissue engineered vascular constructs can be partially characterized by measuring certain mechanical properties such as burst pressure and compliance and submitting them to creep and fatigue tests. Measuring these mechanical properties allows researchers to assess a method’s capability of producing vascular constructs possessing mechanical properties similar to those of native vessels. A system to measure these important mechanical properties in a reliable, precise and repeatable manner was designed and built. The computer controlled system exposed the vascular constructs to various hydrostatic pressures and simultaneously recorded the construct’s internal pressure and external diameter. These values are then used to calculate the mechanical properties of interest

L'origine de Mishtapeu : les relations tutélaires dans les pratiques ancestrales innues par l'analyse des récits traditionnels

Cette étude propose d’examiner deux traits caractéristiques concernant les relations tutélaires chez les Innus et les Naskapis de l’est du Canada. Par contraste avec l’ethnographie d’autres groupes autochtones de la famille algonquienne, celle des Innus, d’un côté, est élusive quant aux relations tutélaires avec les animaux, tandis que de l’autre côté, les relations avec une entité anthropomorphe, Mishtapeu, y sont omniprésentes. Par l’analyse de récits traditionnels, des mythes, ce travail vise à évaluer si cet état singulier des relations tutélaires chez les Innus et Naskapis découlerait de transformations cosmologiques ayant opéré dans un passé plus ou moins récent, et qui auraient eu comme conséquence, premièrement, l’affaiblissement graduel des relations tutélaires avec des animaux, et deuxièmement, l’émergence et la consolidation de Mishtapeu. L’analyse d’un premier groupe de récits, à travers une approche structuraliste syntagmatique, tente d’y repérer la charpente d’un rituel d’obtention d’une entité tutélaire animale afin de démontrer la profonde influence du complexe de l’animal tutélaire chez les Innus. Ce sont les relations avec Mishtapeu que l’analyse d’un deuxième groupe de récits tente d’éclaircir. Les analyses diffusionnistes et symboliques tentent alors de déterminer un moment et un lieu d’émergence de l’entité ainsi que de proposer des pistes conceptuelles crédibles de son origine.This study proposes to examine two characteristic features of guardian relationships among the Innu and Naskapi of eastern Canada. In contrast to the ethnography of other Aboriginal groups of the Algonquian family, the Innu ethnography, on the one hand, is elusive with respect to guardian relationships with animals, while on the other hand, relationships with an anthropomorphic entity, Mishtapeu, are omnipresent. Through the analysis of traditional narratives, also myths, this work aims to evaluate whether this singular state of guardianship relations among the Innu and Naskapi stems from cosmological transformations that took place in the more or less recent past, and that would have resulted, firstly, in the gradual weakening of guardianship relations with animals, and secondly, in the emergence and consolidation of Mishtapeu. The analysis of a first group of stories, through a syntagmatic structuralist approach, attempts to identify the framework of a ritual for obtaining an animal tutelary entity in order to demonstrate the profound influence of the complex of the tutelary animal among the Innu. It is the relationship with Mishtapeu that the analysis of a second group of stories attempts to clarify. Diffusionist and symbolic analyses then attempt to determine a time and place of emergence of the entity as well as to propose credible conceptual tracks of its origin

Effect of Family Medicine Groups on Visits to the Emergency Department among Diabetics in Quebec between 2000 and 2011: A Population-Based Segmented Regression Analysis of an Interrupted Time Series

Poster Presentation Background: Family Medicine Groups (FMG) were introduced in Quebec in 2002 to reorganize primary care practices and encourage team-based and inter-professional approaches to service delivery. We measured the effect of this reform on the rate of emergency department (ED) visits among patients diagnosed with diabetes. Methods: Administrative databases were used to derive the weekly rate of ED visits between April 1, 2000 and March 31, 2012. We performed an interrupted segmented regression analysis to derive the estimated and extrapolated rates of visits in the years following the initial reform implementation. We employed an outcome control series of diabetics visiting the ED to treat appendicitis to strengthen the study’s internal validity. Results: A gradual decline in the rate of visits was observed for short term diabetes related complications and total ED visits. After 9 years of reform implementation, we observed a reduction of 1.42 and 1.70 ED visits per 10,000 diabetics to treat short term complications in urban and rural areas, respectively. A steady decrease was also observed in the total rate of ED visits in urban areas where we observed a reduction of 6.72 visits per 10,000 diabetics 9 years following the reform. Visits coded for appendicitis showed no clinically relevant changes over the study period. Interpretation: Our results suggest that the decreases in the rate of ED visits are attributed to the implementation of the FMG model across the province. The steady decline in the rate of total ED visits in urban areas is of particular relevance where overutilization of the ED is a problem. Evidence of these decreases despite the low-intensity nature of the FMG reform suggests the potential for this model to act as a future platform for implementing comprehensive care models for chronic disease management

The use of artificial wetlands to treat greenhouse effluents

Untreated greenhouse effluents or leak solution constitute a major environmental burden because their nitrate and phosphate concentrations may induce eutrophication. Artificial wetlands may offer a low cost alternative treatment of greenhouse effluents and consequently improve the sustainability of greenhouse growing systems. The objectives of this study were to 1) characterize the efficiency of different types of wetland to reduce ion content of greenhouse tomato effluent, and 2) improve the wetland efficiency by adding carbon of 0-800 mg L-1 sucrose. Experiments were conducted at Laval University where 30 pilot scale horizontal subsurface flow artificial wetlands (0.81 m3) were built. Two types of aquatic macrophytes, Pragmites australis and Typha latifolia, and a control group without plants were tested. The hydraulic retention time was 10 days. During the study, EC of the greenhouse effluent ranged between 1.5 to 5.5 mS cm-1, while 0 to 800 mg L-1 of sucrose was provided to improve the biological activity of the wetland. The macro- and micro-elements, the greenhouse gases (CH4, CO2, N2O) and the population of bacteria were measured for each unit. At commercial scale, two vertical subsurface wetlands (43.2 m3) were installed at Ste-Sophie Québec, on the production site of Les Serres Nouvelles Cultures (Sagami). According to our results, 50-90% of nitrate (NO3-) and 40-100% of phosphate (PO43-) were removed from the effluent. At Laval University, artificial wetlands with Typha latifolia were more efficient than wetlands with Phragmites australis or without plants. Addition of sucrose increased wetlands’ microbial population and consequently reduced the mineral content of the wastewater, but increased significantly the emission of greenhouse gases. Results will further be discussed in terms of the best wetland design to treat greenhouse effluents, but also in terms of the environmental impact

La conscience historique de jeunes franco-ontariens d’Ottawa : histoire et sentiment d’appartenance

RésuméLes écoles de langue française de l’Ontario inscrivent au cœur de leur projet éducatif la mission de transmettre aux élèves francophones une culture commune et un patrimoine historique et de favoriser leur appartenance à l’identité franco-ontarienne. Cet article vise à vérifier si l’Ontario français constitue un point d’ancrage dans la conscience historique des jeunes francophones et s’ils ont recours au passé pour se forger une identité de citoyen.  Nous avons mené une enquête dans deux écoles secondaires d’Ottawa et dans une classe de didactique de l’histoire à l’Université d’Ottawa, où les élèves et les futurs enseignants devaient indiquer leur degré d’attachement identitaire et rédiger un récit sur l’histoire l’Ontario. Il en résulte qu’une appartenance forte à l’identité franco-ontarienne amène les jeunes à puiser dans le passé de l’Ontario français pour consolider et renforcer cette identité dans leur conscience de citoyen. À l’opposé, une identité canadienne et ontarienne forte se traduit pour les élèves par un récit moins engagé politiquement et plus descriptif centré sur l’histoire de son pays ou de sa province.AbstractA central pillar of French-language schooling in Ontario is the mission to transmit a shared culture and history to Francophone students, and encourage their attachment to Franco-Ontarian identity. This article aims to verify whether French Ontario is an important component of the historical consciousness of young Francophones, and if they turn to the past to forge their identities as citizens. Students in two Ottawa secondary schools and future teachers in a history education class at the University of Ottawa were asked to indicate their degree of attachment to Franco-Ontarian identity and to create an account of Ontario history. We found that a strong sense of belonging as Franco-Ontarians leads young people to look to the past to help them construct and reinforce their identity as citizens. On the other hand, strong Canadian and Ontarian identities are expressed by students in more descriptive—and less politically engaged—accounts of the history of their homeland or province

Isolation of free-living dinitrogen-fixing bacteria and their activity in compost containing de-inking paper sludge

Knowledge of the microbiology of dinitrogen (N2)-fixing bacteria in compost rich in de-inking paper sludge (DPS) is limited. Dinitrogen (N2)-fixing bacteria from DPS composts were isolated and studied for their N2-fixing activity in vitro and in vivo. Two Gram-negative N2-fixing isolates were identified as Pseudomonas. At 20 C, both isolates revealed that N2-fixing activity was higher than that of three arctic Pseudomonas strains. Their N2-fixing activity was found to occur between 18 and 25 C, a pattern that was similar to the reference isolate Azotobacter ATCC 7486. Composts successfully showed N2-fixing activity after carbohydrate amendments both with and without inoculation of a N2-fixing isolate. These results suggest that DPS composts support N2-fixing bacteria and that N2-fixing activity is dependent on a usable carbohydrate source. 2005 Elsevier Ltd. All rights reserved.Keywords: Dinitrogen-fixing bacteria; Compost; Paper sludge; Glucose; Pseudomonas balearica; Pseudomonas putid

Electric potential across epidermis and its role during wound healing can be studied by using an in vitro reconstructed human skin

Background : After human epidermis wounding, transepithelial potential (TEP) present in nonlesional epidermis decreases and induces an endogenous direct current epithelial electric field (EEF) that could be implicated in the wound re-epithelialization. Some studies suggest that exogenous electric stimulation of wounds can stimulate healing, although the mechanisms remain to be determined. The Problem : Little is known concerning the exact action of the EEF during healing. The mechanism responsible for TEP and EEF is unknown due to the lack of an in vitro model to study this phenomenon. Basic Science Advances : We carried out studies by using a wound created in a human tissue-engineered skin and determined that TEP undergoes ascending and decreasing phases during the epithelium formation. The in vitro TEP measurements over time in the wound were corroborated with histological changes and with in vivo TEP variations during porcine skin wound healing. The expression of a crucial element implicated in Na+ transport, Na+/K+ ATPase pumps, was also evaluated at the same time points during the re-epithelialization process. The ascending and decreasing TEP values were correlated with changes in the expression of these pumps. The distribution of Na+/K+ ATPase pumps also varied according to epidermal differentiation. Further, inhibition of the pump activity induced a significant decrease of the TEP and of the re-epithelization rate. Clinical Care Relevance : A better comprehension of the role of EEF could have important future medical applications regarding the treatment of chronic wound healing. Conclusion : This study brings a new perspective to understand the formation and restoration of TEP during the cutaneous wound healing process

On passion and moral behavior in achievement settings: The mediating role of pride

The Dualistic Model of Passion (Vallerand et al., 2003) distinguishes two types of passion: harmonious passion (HP) and obsessive passion (OP) that predict adaptive and less adaptive outcomes, respectively. In the present research, we were interested in understanding the role of passion in the adoption of moral behavior in achievement settings. It was predicted that the two facets of pride (authentic and hubristic; Tracy & Robins, 2007) would mediate the passion-moral behavior relationship. Specifically, because people who are passionate about a given activity are highly involved in it, it was postulated that they should typically do well and thus experience high levels of pride when engaged in the activity. However, it was also hypothesized that while both types of passion should be conducive to authentic pride, only OP should lead to hubristic pride. Finally, in line with past research on pride (Carver, Sinclair, & Johnson, 2010; Tracy et al., 2009), only hubristic pride was expected to negatively predict moral behavior, while authentic pride was expected to positively predict moral behavior. Results of two studies conducted with paintball players (N=163, Study 1) and athletes (N=296, Study 2) supported the proposed model. Future research directions are discussed in light of the Dualistic Model of Passion