Les travaux présentés dans cette thèse visent à apporter des outils d’aide à la décision à partir de modèles prenant en compte une représentation Info-Gap des différentes sources de méconnaissance du système. Il est en effet possible en utilisant des simulations numériques de développer des indicateurs de support à la décision sous un certain niveau d’incertitude aléatoire ou épistémique. Le principe de conception est ici utilisé au sens large, et peut entrer sans le cadre du dimensionnement structural de composants, de la définition de l’amplitude d’excitation maximum d’un essai, ou encore de la mise en place d’une distribution de capteurs. Ces différentes méthodologies sont ici développées puis appliquées sur des systèmes académiques et industriels / The work presented in this PhD thesis aims at propose new decision making tools in order to take into account a Info-Gap modelling of the different sources of lack of knowledge. Indeed, numerical simulation allow to develop useful indicators for decision making under a given level of random or epistemic uncertainty. The design principle is hereby used in its very large sense, and can stand for structural component design, maximum load definition fir vibrating test or sensor placement design. In this manuscript, these different methodologies are developed and applied to academic and industrial structures.

The objective of this research was to investigate the behavioural, physiological and immunological effects of routine surgical procedures in neonatal swine in order to provide producers with science-based recommendations. In the first experiment, low- or average-birth-weight piglets that were tail docked and ear notched at 1 or 3 days of age showed subtle differences resulting from age at processing. However, low-birth-weight male piglets had the lowest attendance during nursing bouts and spent the greatest amount of time lying alone. Vocalization data suggests that ABW piglets may be less reactive to the procedures on d 1. Overall, the decreased vitality and reduced survivability of low-birth-weight piglets suggests that delaying processing until day 3 for these piglets may be preferable. In the second experiment, the effects of docked tail length and nursery stocking density on tail-biting behaviour, skin lesions and rectal prolapses were investigated. Long-tailed pigs (docked to 4.5 cm at birth) were most vulnerable to tail-biting, and housing at a moderate versus high nursery stocking density was not sufficient to reduce tail-biting. High nursery stocking density negatively impacted skin lesion scoring and growth performance for the majority of the grower-finisher period. Pigs from either nursery stocking density and docked tail length groups were equally likely to be affected by prolapsed rectal mucosa. Given the decreased survivability and significantly lighter weaning weight for low-birth-weight piglets compared to those of average-birth-weight, delaying processing of low-birth-weight piglets may be the most humane option. Further, until tail-biting is better understood and a more effective solution found, the routine docking of tails remains the optimal method for balancing a situation with enormous welfare-reducing potential. / Agriculture and Agri-Food Canada

The credit rating industry is characterised by the high concentration of a small number of firms and, allegedly, this concentration stems from certain anticompetitive behaviours made manifest by the dominant firms in the industry. Therefore, as has yet to be done in empirical research, the purpose of this study is to carry out an exploration of the antitrust behaviours supposedly perpetuated by agents in the credit rating process for debt finance. The aim is to determine what influences, if any, the interactions and relationships in the rating process have on the sustenance of the oligopoly in the rating industry and on impeding new rating agencies trying to enter the market. Through the application of thematic analysis, this study aims to gather evidence on the behavioural motivations of rating analysts and underwriters in the rating process. Furthermore, the theoretical framework suggests notching and tying to be the anticompetitive behaviours that strengthen the oligopoly. Hence, the study finds that the drivers of anticompetitive notching in the rating process are the taking of haircuts and mapping, the guise of protecting investors’ interests, punitive ratings and a quid pro quo rating norm. Similarly, it finds that the enablers of anticompetitive tying are continuous dealing in the rating process, covert negotiation, repeat rating requests, ancillary services and the regulatory overdependence on credit ratings. In addition, this thesis explores the impediments of new rating agencies trying to enter the credit rating industry and finds that new rating agencies face peculiar market, regulatory and organisational barriers. Firstly, the market barriers comprise arbitrage, economic rents, investor preference and the issuer-pay model. Secondly, the regulatory barriers are discretionary regulation, new regulations and the designation of nationally recognised statistical rating organisation status. Lastly, the organisational barriers include down-trading, inadequate funding, the lack of geographic spread, low added intellectual value and a narrow product and service scope. Finally, this research recommends for regulatory authorities to agree to a harmonised convention on the recognition of credit rating agencies that may lead to the emergence of new robust agencies. It also proposes the standardisation of mapping practices in the notching process to reduce rating variance among credit rating agencies. Lastly, the research offers evidence of notching for competition and tying through informal services that may substantiate antitrust liability for possible antitrust intervention.

Hip resurfacing is an alternative to total hip arthroplasty for the young and active patient likely to outlive traditional means of hip joint replacement. The acetabular cup is implanted in much the same fashion as an uncemented total hip arthroplasty, however, implantation of the femoral component is unique to hip resurfacing, presenting both distinct benefits and limitations. Hip resurfacing spares much of the proximal femur including the femoral neck and portions of the femoral head. This may be advantageous if the patient requires revision surgery; however, preservation of the femoral neck bears with it the risk of femoral neck fracture. The exact mechanism of neck fracture is not fully understood. Avoiding potential fracture risks is vital to ensuring optimal patient outcomes. The current work investigated mechanical femoral head preparatory factors that may predispose to femoral neck fracture. Intra-operative computer navigation is emerging as the gold-standard in orthopaedic care. In hip resurfacing, navigation may improve the surgeon’s ability to optimally implant the resurfacing prosthesis; however, much of this technology is still in its infancy and requires investigation into the accuracy and repeatability of this peri-operative tool. Pre-operative planning can assist the surgeon in optimally determining the size and position of the resurfacing components, specifically in reference to the patient’s unique anatomy, prior to performing the operation. This may aid in correct implant selection and provide a basis on which to conduct intra-operative navigation. However, the accuracy and repeatability of pre-operative planning for hip resurfacing has not yet been established. Thus, this body of work looked to establish a clear methodology for pre-operative planning, intra-operative computer navigation and surgical technique in order to optimize preparation of the femoral head, ultimately reducing the risk of femoral neck fracture in hip resurfacing.

Hip resurfacing is an alternative to total hip arthroplasty for the young and active patient likely to outlive traditional means of hip joint replacement. The acetabular cup is implanted in much the same fashion as an uncemented total hip arthroplasty, however, implantation of the femoral component is unique to hip resurfacing, presenting both distinct benefits and limitations. Hip resurfacing spares much of the proximal femur including the femoral neck and portions of the femoral head. This may be advantageous if the patient requires revision surgery; however, preservation of the femoral neck bears with it the risk of femoral neck fracture. The exact mechanism of neck fracture is not fully understood. Avoiding potential fracture risks is vital to ensuring optimal patient outcomes. The current work investigated mechanical femoral head preparatory factors that may predispose to femoral neck fracture. Intra-operative computer navigation is emerging as the gold-standard in orthopaedic care. In hip resurfacing, navigation may improve the surgeon’s ability to optimally implant the resurfacing prosthesis; however, much of this technology is still in its infancy and requires investigation into the accuracy and repeatability of this peri-operative tool. Pre-operative planning can assist the surgeon in optimally determining the size and position of the resurfacing components, specifically in reference to the patient’s unique anatomy, prior to performing the operation. This may aid in correct implant selection and provide a basis on which to conduct intra-operative navigation. However, the accuracy and repeatability of pre-operative planning for hip resurfacing has not yet been established. Thus, this body of work looked to establish a clear methodology for pre-operative planning, intra-operative computer navigation and surgical technique in order to optimize preparation of the femoral head, ultimately reducing the risk of femoral neck fracture in hip resurfacing.

Shoulder arthroplasty surgery has shown remarkable progress during the last few decades. A number of factors affect postoperative range of motion, pain and prosthetic durability. Among these factors, the length of the lever arm and joint stability is the ones that can be altered by the selected prosthetic component. It is uncertain how much of the normal anatomy needs to be re-established. Stemless prostheses with total reliance on metaphyseal fixation were introduced in France in 2004 (TESS, Zimmer Biomet). The goals were to avoid stem-related complications. Stemless implants have other potential benefits, including the ability to restore shoulder anatomy. Study I: This is a prospective cohort study of 49 patients with one of two versions of the TESS prosthesis (anatomical or reverse) with clinical and radiological follow-up ranging from 9–24 months. The TESS prosthesis showed short-term results that were comparable with other shoulder prosthetic systems. Study II: This is a prospective comparative non-randomised study of 37 patients (40 shoulders) who underwent TESS reverse shoulder arthroplasty (RSA) with a follow-up ranging from 15–66 months. We found a significant improvement in functional outcome and reduction of pain in both stemmed and stemless groups. Glenoid overhang influenced the occurrence of scapular notching (SN). Study III: This is a radiological study showing that CT had a good reliability and reproducibility in estimating LHO. Study IV: This is a prospective radiological study of 69 patients (70 shoulders) with primary osteoarthritis (OA) who had undergone stemless total anatomical shoulder arthroplasty (TSA). This study showed that stemless anatomical TSA could be useful in restoring shoulder anatomy. Study V: This is a prospective study of 44 patients with OA who had undergone stemless anatomical TSA with a clinical and radiological follow up ranging from 12 – 50 months. Our study showed that LHO reconstruction close to the anatomy of a healthy contralateral shoulder improved shoulder function. Stemless anatomical TSA help to restore LHO. Increasing LHO may have a negative effect on shoulder function at three months but had no effect at 12 months. The main conclusions of this thesis are: 1. TSA (anatomic and reverse) using stemless humeral components is reliable if bone quality is adequate. The complication rate is comparable with other shoulder prosthetic systems. 2. Glenoid overhang decreased complications in RSA. 3. LHO measurement on AP radiographs is less reliable and underestimates the distance when compared with CT. 4. Stemless TSA could be of help in reconstructing shoulder anatomy. 5. Shoulder reconstruction close to the anatomy of a healthy contralateral shoulder improves shoulder function. / Axelprotes kirurgi har visat avsevärd utveckling under de senaste decennierna. Ett antal faktorer påverkar postoperativt rörelseomfång, smärta och proteshållbarhet. Bland dessa faktorer utgör längden av hävarmen och ledstabilitet de faktorer som kan ändras genom val av proteskomponent. Det är osäkert om den normala anatomin måste återupprättas. Oskaftad protes med eliminering av humerusstamm och tillit till metafysär fixering introducerades i Frankrike år 2004 (TESS, Zimmer Biomet). Målen var att undvika stam relaterade komplikationer. Oskaftat implantat har andra potentiella fördelar, inklusive möjligheten att återställa axelnsanatomi. Syftet med denna avhandling var: (1) Att undersök radiologisk stabilitet av oskaftade axelproteser. (2) Att studera effekten av protes placering vid omvänd axelartroplastik både radiologiska och kliniskt utfall. (3) Att studera tillförlitlighet av mätningen av den laterala humeral offset (LHO), avståndet mellan processus coracoideus till laterala kanten av tuberkulum majus, med användning av CT eller röntgen. (4) Att studera oskaftad axelprotes förmåga att återställa axelnsanatomi. (5) Att studera den kliniska betydelsen av LHO återställning i för det funktionella resultatet efter axelartroplastik. Studie I: Detta är en prospektiv kohortstudie av 49 patienter med en av de två versionerna av TESS (anatomisk eller omvänd) med klinisk och radiologisk uppföljning från 9-24 månader. TESS protes visade lovande resultat på kort sikt med komplikationer som var jämförbar med andra axelprotessystem. Studie II: Detta är en prospektiv jämförande icke-randomiserad studie av 37 patienter (40 skuldror) som opererades med TESS omvänd axelartroplastik med en uppföljning från 15-66 månader. Vi fann en signifikant förbättring av funktion och minskning av smärta i både skaftad och oskaftad grupper. Glenoid overhang bedöms påverka risken för scapular notching (SN). Studie III: Detta är en radiologisk studie som visade att CT hade god tillförlitlighet och reproducerbarhet att mäta LHO. Studie IV: Detta är en prospektiv radiologisk studie av 69 patienter (70 skuldror) med primär artros som hade genomgått oskaftad total anatomisk axelprotes. Denna studie visade att oskaftad axelprotes kan vara till hjälp att återställa axelnsanatomi. Studie V: Detta är en prospektiv studie av 44 patienter med unilateral primär artros som hade genomgått oskaftad total axelprotes med en klinisk och radiologisk uppföljning från 12 - 50 månader. Vår studie visade att LHO rekonstruktion till den friska axeln förbättrar axelfunktion. Oskaftat implantat kan vara av hjälp till att återställa LHO. Ökad LHO kan ha en negativ effekt på axelnsfunktion vid tre månader, men denna effekt påvisade ej vid 12 månader. De viktigaste slutsatserna i denna avhandling är: 1. Oskaftad total axel artroplastik (anatomisk och omvänd) är tillförlitlig om benkvalitén är god med komplikationer som var jämförbar med andra axelprotessystem. 2. Glenoid overhang minskar komplikationer vid omvänd axelartroplastik. 3. LHO mätningen på röntgen är mindre tillförlitlig och underskattar avståndet jämfört med CT. 4. Oskaftad axelprotes skulle kunna vara till hjälp för att rekonstruera axelnsanatomi. 5. Axel rekonstruktion inom anatomi till att efterlikna anatomi på den friska kontralaterala axeln förbättrar axelfunktion.