Concurrence est concernée par les systèmes informatiques des agents multiples qui interagissent les uns avec les autres. Bisimilarité est l'un des principales représentantes de ces derniers. Programmation concurrente par contraintes (ccp) est un formalisme qui combine le point de vue traditionnel des formules algébriques et opérationnelles des calculs de processus avec une notion déclarative basée sur logique. La définition standard de bisimilarité n'est pas complètement satisfaisante pour ccp car il donne une équivalence qui est trop à grain fin. Nous introduisons une sémantique de transitions étiquetées et une notion de bisimilarité totalement abstraite à l'équivalence observationnelle en ccp. Lorsque l'espace d'état d'un système est fini, la notion ordinaire de bisimilarité peut être calculé par l'algorithme de partition de raffinement, mais, cet algorithme ne fonctionne pas pour la bisimilarité de ccp. Par conséquent, nous fournissons un algorithme que nous permet de vérifier bisimilarité forte pour ccp, en utilisant un pré-raffinement et une fonction de partition basée sur la bisimilarité irredondante. Bisimilarité faible est une équivalence comportementale obtenue en prenant en compte uniquement les actions qui sont observables dans le système. Typiquement, le raffinement de partition standard peut être utilisé pour décider bisimilarité faible simplement en utilisant la réduction de Milner allant de faible à forte. Nous démontrons que, en raison de ses impliquées transitions étiquetées, la technique mentionnée ci-dessus ne fonctionne pas pour ccp. Nous donnons une réduction qui nous permet d'utiliser cet algorithme pour ccp pour décider cette équivalence.

Le concept de réversibilité est ancien, mais il soulève de nos jours beaucoup d'intérêt. Il est en effet exploité dans de nombreux domaines tels que la conception de circuits, le débogage et le test de programmes, la simulation et l'informatique quantique. L'idée d'un modèle de programmation réversible peut se montrer particulièrement intéressante pour la construction de systèmes sûrs de fonctionnement, ne serait-ce que parce que plusieurs techniques connues pour la construction de tels systèmes exploitent une forme ou une autre de retour en arrière ou de reprise. Nous poursuivons dans cette thèse l'étude entreprise avec CCS réversible par Vincent Danos et Jean Krivine, en définissant un pi-calcul d'ordre supérieur réversible (rhopi). Nous prouvons que le modèle obtenu est causalement cohérent, et que l'on peut encoder fidèlement rhopi dans une variante du pi-calcul d'ordre supérieur. Nous définissons également une primitive de reprise à grain fin qui permet de contrôler le retour en arrière dans une exécution concurrente. Nous spécifions formellement la sémantique de cette primitive, et nous montrons qu'elle possède de bonnes propriétés, y compris en présence d'opérations de reprise concurrentes. Enfin nous définissons un algorithme concurrent implantant cette primitive de reprise et ous montrons que cet algorithme respecte la sémantique définie. / Reversible computing has a long history. Nowadays, reversible computing is attracting increasing interest because of its potential applications in diverse fields, including hardware design, biological modelling, program debugging and testing and quantum computing. Of particular interest is the application of reversible computation notions to the study of programming abstractions for dependable systems, because several techniques used to build dependable systems rely on some forms of undo or rollback. We continue, in this thesis, the study undertaken on reversible CCS by Vincent Danos and Jean Krivine, by defining a reversible higher-order pi-calculus (rhopi). We prove that reversibility in our calculus is causally consistent and that one can encode faithfully rhopi into a variant of HOpi. Moreover we design a fine-grained rollback primitive able to control the rollback of a concurrent execution. We give a formal specification of this primitive and show that it enjoys good properties, even in presence of concurrent conflicting rollbacks. We then devise a concurrent algorithm implementing such primitive and show that the algorithm respects the defined semantics.

Introdução: A litotripsia extracorpórea por ondas de choque (LEOC) é o tratamento mais utilizado para cálculos renais de até 20 mm. O uso adjuvante de algumas drogas pode aumentar as taxas de sucesso do procedimento e diminuir a sua morbidade. Objetivos: Avaliar os efeitos da tansulosina e do nifedipino nas taxas de sucesso, nos episódios de dor e na velocidade de eliminação dos fragmentos após o tratamento de cálculos renais de 5 a 20 mm com uma única sessão de LEOC. Casuística e Métodos: Foram estudados prospectivamente 136 indivíduos portadores de cálculos renais entre 5 e 20 mm, submetidos à LEOC entre 2006 e 2009. Os pacientes foram divididos aleatoriamente em 3 grupos para receber diariamente tansulosina 0,4 mg, nifedipino retard 20mg ou placebo por até 30 dias da realização de LEOC. A analgesia foi feita com celecoxibe 200 mg. Os pacientes foram avaliados semanalmente por meio de radiografia de abdome. Foi definido como sucesso do tratamento a ausência de fragmentos maiores que 4 mm ao final de 30 dias. Os parâmetros avaliados foram: taxa de sucesso do tratamento, ocorrência de rua de cálculos, necessidade de analgésicos, intensidade de dor após a LEOC, tempo de eliminação de fragmentos, efeitos adversos da medicação e visitas ao Pronto Socorro. Resultados: Cento e onze pacientes completaram o estudo. Não houve diferenças demográficas entre os pacientes e nem em relação ao tamanho dos cálculos entre os grupos. As taxas de sucesso foram de 60,5% (23 de 38) no Grupo Tansulosina, 48,6% (17 de 35) no Grupo Nifedipino e 36,8% (14 de 38) no Grupo Placebo. (p=0,118) Entre os pacientes com cálculos de 10 a 20 mm, a taxa de sucesso foi significativamente maior nos Grupos Tansulosina (61,9%) e Nifedipino (60,0%) do que no Grupo Placebo (26,1%) (p=0,024), porém não foi significativa entre os cálculos de 5 a 9 mm (p=0,128). O Número Necessário para Tratar (NNT) da Tansulosina foi de 2,9 e o do Nifedipino foi de 3, considerando-se o uso para cálculos de 10 a 20 mm. Os pacientes que usaram nifedipino tiveram mais efeitos adversos do que os do Grupo Placebo (28,5 % x 2,6% respectivamente, p = 0,009), porém sem levar à interrupção do uso da drogas. Não houve diferença significativa entre os grupos Tansulosina x Nifedipino e Tansulosina x Placebo em relação aos efeitos adversos (p= 0,15 e p = 0,054, respectivamente). Não houve diferença entre os grupos com relação à intensidade da dor observada após o tratamento (p=0,28), ao número de comprimidos de Celecoxibe (p=0,39), ao tempo de eliminação dos fragmentos (p=0,6), à ocorrência de rua de cálculos (p=0,482) e ao número de vistas ao Pronto Socorro (p=0,175). Conclusões: O uso adjuvante de tansulosina ou de nifedipino após LEOC aumenta a taxa de sucesso para cálculos renais entre 10 e 20 mm, porém sem diminuir a intensidade da dor ou a necessidade de analgésicos após o tratamento, nem o tempo de eliminação dos fragmentos / Purpose: We evaluated the effects of the adjuvant use of tamsulosin and nifedipine after extracorporeal shock wave lithotripsy (SWL) for 5-20 mm kidney stones. Materials and Methods: We conducted a randomized double-blind trial involving 136 patients with radiopaque kidney stones between 2006 and 2009. Patients were divided into three groups to receive daily treatments of 0.4 mg tamsulosin, 20 mg nifedipine retard or placebo for up to 30 days after one session of SWL. The parameters assessed were success rate, analgesic requirements, pain intensity, time to clearance, adverse effects and occurrence of Steinstrasse. Results: The success rate was 60.5% (23 of 38) in the Tamsulosin group, 48.6% (17 of 35) in the Nifedipine group and 36.8% (14 of 38) in the Placebo group (p=0.118). For stones ranging from 10 to 20 mm, the success rates were significantly higher in the Tamsulosin (61.9%) and Nifedipine groups (60.0%) when compared with the Placebo group (26.1%) (p=0.024), but not for the 5-9 mm stones (p=0.128). The Number Needed to Treat was 2.9 for tamsulosin and 3 for nifedipine. Adverse events were more frequent in the Nifedipine than the Placebo Group (28.5% vs. 2.6%, respectively, p=0.009). There was no difference among groups with regard to stone and demographic characteristics, pain intensity, time to clearance and Steinstrasse. Conclusions: Adjuvant use of tamsulosin or nifedipine after SWL significantly increased the success rates for 10 to 20 mm renal stones and could be recommended. Both drugs had similar beneficial effects and adverse events

Introdução: A eficácia da litotripsia extracorpórea por ondas de choque (LECO) no tratamento de cálculos em cálice inferior do rim ainda é motivo de controvérsia. Variáveis que possam impactar nos resultados da LECO ainda não estão bem estabelecidos. Objetivo: Avaliar quais variáveis impactam na fragmentação e eliminação de cálculos em cálice inferior do rim após LECO. Material e Métodos: Avaliamos prospectivamente pacientes submetidos à LECO para tratamento de cálculos de cálice inferior de 5 a 20 mm. O índice de massa corpórea (IMC) e a circunferência abdominal foram medidos em cada caso. Um único radiologista, cego aos resultados da LECO, mensurou o tamanho, área e densidade dos cálculos, assim com a distância pele-cálculo, o comprimento, largura e altura infundibular, e o ângulo pielo-calicinal baseado na tomografia computadorizada (TC) realizada antes do procedimento. As taxas de fragmentação, sucesso (cálculos residuais <= 4 mm em pacientes assintomáticos) e eliminação completa foram avaliadas após uma única sessão de LECO, em uma segunda TC, realizada 12 semanas após o procedimento. Análises uni e multivariada foram realizadas. O nível de significância foi estabelecido em p<0,05. Resultados: Cem pacientes foram incluídos no estudo. A idade e IMC médios foram de 47,1 ± 12,5 anos e 28,0 ± 4,7 Kg/m2. O tamanho médio dos cálculos foi de 9,1 ± 3,0 mm. As taxas globais de fragmentação, sucesso e eliminação completa foram de 76%, 54% e 37%, respectivamente. Após a regressão logística múltipla, o IMC (p=0,004) e a densidade (p=0,005) do cálculo impactaram significativamente na fragmentação. O tamanho (p=0,039) e a densidade (p=0,012) do cálculo impactaram significativamente na taxa de sucesso, enquanto o tamanho do cálculo (p=0,029), sua densidade (p=0,046) e o comprimento infundibular (p=0,015) impactaram significativamente na taxa de eliminação completa. As maiores taxas de fragmentação, sucesso e eliminação completa foram encontradas em pacientes com IMC <= 30 Kg/m2, cálculo <=10 mm e <= 900 UH, e comprimento infundibular <= 25 mm. A coexistência das variáveis significantes de mau prognóstico proporcionou uma taxa de eliminação completa <20%. As taxas de doentes livres de cálculos foram menores em pacientes com medidas anatômicas desfavoráveis em relação àqueles com medidas favoráveis, embora a diferença tenha sido significante apenas para o comprimento infundibular (14% vs. 43%, p=0,02). Conclusão: Pacientes com IMC > 30 kg/m2 apresentam uma menor taxa de fragmentação dos cálculos. Tamanho (> 10 mm) e densidade (>900 UH) do cálculo, assim com o comprimento infundibular (>25 mm) influenciam negativamente nos resultados da LECO / Introduction: The efficiency of shock wave lithotripsy (SWL) for treatment of lower pole stone is still controversial. Variables that could impact on SWL outcomes are not well established. Objective: To evaluate which variables impact fragmentation and clearance of lower pole calculi after SWL. Material and Methods: We prospectively evaluated patients undergoing SWL for solitary lower pole kidney stones ranging from 5-20mm. Patient\'s body mass index (BMI) and abdominal waist circumference were recorded. One radiologist, blinded to SWL outcomes, measured stone size, area and density, stone-skin distance, infundibular length, width and height, and infundibulopelvic angle based on baseline noncontrast computed tomography (NCCT). Fragmentation, success (residual fragments <= 4mm in asymptomatic patients) and stone-free rates were evaluated after one single SWL by NCCT 12 weeks post-operatively. Univariate and multivariate analysis were performed. Significance level was set at p < 0.05. Results: One hundred patients were enrolled in this study. Mean age and BMI were 47.1 ± 12.5 years and 28.0 ± 4.7 Kg/m2. Mean stone size was 9.1 ± 3.0 mm. Overall fragmentation, success, and stone-free rates were 76%, 54%, and 37%, respectively. After multiple logistic regression, BMI (p=0.004) and stone density (p=0.005) impacted significantly on fragmentation. Stone size (p=0.039) and stone density (p=0.012) impacted significantly on success rate, whereas stone size (p=0.029), stone density (p=0.046), and infundibular length (p=0.015) impacted significantly on stone-free rate. The higher fragmentation, success and stone-free rates were found for patients with BMI <= 30 Kg/m2, stone <=10 mm and <=900 HU, and infundibular length <= 25 mm. The coexistence of unfavorable variables led to a stone-free rate <20%. Stone-free rates were lower for patients with unfavorable anatomic features compared to those with favorable measurements, although the difference was only significant for infundibular length (14% vs. 43%, p=0.02). Conclusion: Patients with BMI >30 Kg/m2 have a lower stone fragmentation rate. Stone size ( > 10 mm) and stone density (>900 UH), as well as infundibular length ( > 25 mm) impact negatively on SWL outcomes

A nefrolitíase pode ser definida como uma consequência de alterações nas condições de cristalização da urina no trato urinário. A incidência desta patologia nos Estados Unidos é de 5 % em mulheres e 12 % em homens e sua recorrência é de 50 % em 5 a 10 anos e 75 % em 20 anos. Cálculos renais são compostos por porções inorgânicas e orgânicas. Em seres humanos, a porção inorgânica é principalmente composta por sais de cálcio (cerca de 80 %), seguido pelos cálculos de ácido úrico (5-10 %). Estes também podem ser compostos por estruvita, cistina, entre outros.Quanto à matriz orgânica, ela é formada predominantemente por proteínas, como a nefrocalcina, osteopontina, hemoglobina, proteína de Tamm Horsfall, entre outras. As formas de tratamento desta patologia consistem em intervenção cirúrgica ou litotripsia de ondas de choque extracorpóreas (LOCE). As plantas pertencentes ao gênero Copaifera (Fabaceae, caesalpinoideae) são nativas de regiões tropicais da América Latina e da África Ocidental. Conhecidas no Brasil como copaibeiras, e popularmente como pau dóleo, estas árvores encontram-se amplamente distribuídas na Amazônia e regiões centrais do Brasil. C. langsdorffii Desf. é a espécie mais comum fora da Região Amazônica. Estudos realizados com seu óleoresina demonstraram diferentes atividades biológicas, tais como cicatrizante e antiinflamatória. Partes aéreas de C. langsdorffii foram coletadas no Campus da Faculdade de Ciências Farmacêuticas de Ribeirão Preto - USP e utilizadas na obtenção do extrato hidroalcoólico 7:3. Este extrato foi submetido a diferentes modalidades cromatográficas com o objetivo de isolar seus principais componentes. Para os ensaios in vivo, as pastilhas de oxalato de cálcio foram obtidas por meio de uma reação de supersaturação e a nefrolitíase foi induzida introduzindo-se estas pastilhas na bexiga de ratos. O tamanho dos cálculos, a bioquímica urinária e variáveis gerais, tais como peso corpóreo, volume de urina coletada por 24 horas e volume de água ingerida foram determinados. O extrato hidroalcoólico de partes aéreas de C. langsdorffii é constituído majoritariamente de compostos polares. Duas substâncias pertencentes à classe dos flavonóides foram isoladas e identificadas: os flavonóis quercetrina (quercetina 3-O--L-ramnopiranosídeo) e canferol 3-O--Lramnopiranosídeo. No ensaio in vivo, os animais tratados com o extrato hidroalcoólico de C. langsdorffii apresentaram menor média na massa de cálculos formados e menor média no número de cálculos formados (matriz + satélites). Além disso, sugere-se que o tratamento com o extrato altere a morfologia dos cálculos, já que a pressão necessária para desintegrar os cálculos dos animais sem tratamento é, em média, cerca de duas vezes maior do que a necessária para desintegrar aqueles retirados de animais tratados (6,90±3,45 vs. 3,00±1,51 kgf). / Nephrolithiasis can be defined as a consequence of alterations in the crystallization conditions of urine in the urinary tract. The incidence of the disease in United States is 5 % in women and 12 % in men and the recurrence is 50 % in 5 to 15 years and 75 % in 20 years. Renal calculi are composed by inorganic and organic portions. In humans, the inorganic portion is principally composed by calcium salts (around 80 %) and uric acid calculi (5-10 %). Also, they can be composed by struvite, cystine and so on. As far as the organic matrix is concerned, proteins, like nephrocalcin, osteopontin, hemoglobin and Tamm Horsfall protein basically compose it. The current treatment of nephrolithiasis is based on surgical interventions and extracorporeal shock wave lithotripsy (ESWL). Plants belonging to the genus Copaifera (Fabaceae, caesalpinoideae) are native of tropical regions of Latin America and Occidental Africa. In Brazil, known as copaibeiras, they are widely found in Amazon and central regions. C. langsdorffii Desf. is the specie commonly found out of the Amazon region. Studies with its oil-resin have showed biological properties, including healing and anti-inflammatory activities. Aerial parts of C. langsdorffii were collected at the FCFRP - USP Campus and used to obtain the hydroalcoholic extract 7:3. The extract was submitted to several chromatographic procedures in order to isolate its main compounds. In the in vivo assays, calcium oxalate disks were obtained by a supersaturation reaction and nephrolitiasis was induced by the introduction of those disks in the bladder of rats. Calculi size, urinary biochemistry and general parameters, e.g. body weight, 24 hours urine and water volume ingested were determined. Hydroalcoholic extract of aerial parts of C.langsdorffii is rich in polar compounds. Two compounds from flavonoids group were isolated and identified: the flavonols quercitrin (quercetin 3-O--L-rhamnopyranoside) and kaempferol 3-O--L-rhamnopyranoside. Results of in vivo experiments demonstrated that animals treated with C. langsdorffii showed reductions in the mean calculi mass and in the mean number of calculi (matrix and satellites). Besides, the experiment suggests that the treatment with C. langsdorffii modifies the calculi morphology, since the pressure needed to break calculi of non-treated animals is more than two-fold larger than the pressure needed to break those taken from treated animals (6,90±3,45 vs. 3,00±1,51 kgf).

Noncommutative geometry has over the past four of decades grown into a rich field of study. Novel ideas and concepts are rapidly being developed, and a notable application of the theory outside of pure mathematics is quantum theory. This thesis will focus on a derivation-based approach to noncommutative geometry using the framework of real calculi, which is a rather direct approach to the subject. Due to their direct nature, real calculi are useful when studying classical concepts in Riemannian geometry and how they may be generalized to a noncommutative setting. This thesis aims to shed light on algebraic aspects of real calculi by introducing a concept of morphisms of real calculi, which enables the study of real calculi on a structural level. In particular, real calculi over matrix algebras are discussed both from an algebraic and a geometric perspective.Morphisms are also interpreted geometrically, giving a way to develop a noncommutative theory of embeddings. As an example, the noncommutative torus is minimally embedded into the noncommutative 3-sphere. / Ickekommutativ geometri har under de senaste fyra decennierna blivit ett etablerat forskningsområde inom matematiken. Nya idéer och koncept utvecklas i snabb takt, och en viktig fysikalisk tillämpning av teorin är inom kvantteorin. Denna avhandling kommer att fokusera på ett derivationsbaserat tillvägagångssätt inom ickekommutativ geometri där ramverket real calculi används, vilket är ett relativt direkt sätt att studera ämnet på. Eftersom analogin mellan real calculi och klassisk Riemanngeometri är intuitivt klar så är real calculi användbara när man undersöker hur klassiska koncept inom Riemanngeometri kan generaliseras till en ickekommutativ kontext. Denna avhandling ämnar att klargöra vissa algebraiska aspekter av real calculi genom att introducera morfismer för dessa, vilket möjliggör studiet av real calculi på en strukturell nivå. I synnerhet diskuteras real calculi över matrisalgebror från både ett algebraiskt och ett geometriskt perspektiv. Morfismer tolkas även geometriskt, vilket leder till en ickekommutativ teori för inbäddningar. Som ett exempel blir den ickekommutativa torusen minimalt inbäddad i den ickekommutativa 3-sfären.

No tratamento do cálculo coraliforme por nefrolititomia percutânea, há cirurgias com poucas dificuldades e pacientes que evoluem sem complicações, como há casos muito difíceis, com pós-operatório extremamente complicado. O objetivo deste estudo é analisar os fatores de risco pré, intra e pós-operatórios, relacionados com complicações e insucessos da nefrolitotomia percutânea no tratamento do cálculo coraliforme. Foram estudados 57 pacientes portadores de 72 cálculos coraliformes. Houve correlação estatisticamente significante entre complicação e os seguintes fatores: infecção do trato urinário no pré-operatório e número de punções renais. Em relação a insucesso os fatores de risco foram: infecção do trato urinário no pré-operatório e via excretora sem dilatação / During a percutaneous nephrolithotomy (PNL) procedure there are cases with no difficulties and no complications. In the other hand, there are cases very hard to treat with a higher surgical risk and post-operative complications.The goal of this study is to analyze the pre, intra and postoperative risk factors related to surgical complications and nonsuccess rates of PNL as treatment for staghorn stone. Fifty-seven patients with seventy-two staghorn calculi were studied. There have been significant statistical correlation between complications and: postoperative urinary tract infections and the number of renal access required. When considering nonsuccess rate, there was association with the following risk factors: postoperative urinary tract infections and absence of dilatation of collecting system

No tratamento do cálculo coraliforme por nefrolititomia percutânea, há cirurgias com poucas dificuldades e pacientes que evoluem sem complicações, como há casos muito difíceis, com pós-operatório extremamente complicado. O objetivo deste estudo é analisar os fatores de risco pré, intra e pós-operatórios, relacionados com complicações e insucessos da nefrolitotomia percutânea no tratamento do cálculo coraliforme. Foram estudados 57 pacientes portadores de 72 cálculos coraliformes. Houve correlação estatisticamente significante entre complicação e os seguintes fatores: infecção do trato urinário no pré-operatório e número de punções renais. Em relação a insucesso os fatores de risco foram: infecção do trato urinário no pré-operatório e via excretora sem dilatação / During a percutaneous nephrolithotomy (PNL) procedure there are cases with no difficulties and no complications. In the other hand, there are cases very hard to treat with a higher surgical risk and post-operative complications.The goal of this study is to analyze the pre, intra and postoperative risk factors related to surgical complications and nonsuccess rates of PNL as treatment for staghorn stone. Fifty-seven patients with seventy-two staghorn calculi were studied. There have been significant statistical correlation between complications and: postoperative urinary tract infections and the number of renal access required. When considering nonsuccess rate, there was association with the following risk factors: postoperative urinary tract infections and absence of dilatation of collecting system

The work presented in this document in an account of my work as a PhD student at LIX, Ecole Polytechnique, in the COMETE team under the supervision of Catuscia Palamidessi. During these studies, I have been in interested in the various aspects of concurrency covered by the COMETE team activities. The initial goal of my thesis was to investigate the aspects related to process calculi based formalisms to express and analyze Security Protocols. The ultimate goal was to makes some advances towards the automatic verification of security properties. In particular, I was interested in information-hiding protocols which require no cryptography, but normally use randomized mechanisms and therefore exhibit probabilistic behavior. Information hiding protocols are used typically in networks, and they are run by parties that reside in different locations of the system, and therefore interact asynchronously. The first work that I did was to try to give a correct meaning to the various notions of formal asynchronous communications used in various models, in particular between the field of concurrency and the field of distributed computing, where this was a recurrent question. These results are presented in the first part of this document. Being interested in the formal aspects of information-hiding problems, I took part in the preparation of the journal version of [BP09], and started preparing an automated probabilistic anonymity checker based on the formalism presented in this document. This lead to an initial draft of an implementation presented in http://vamp.gforge.inria.fr/. The formalism for this analysis is presented in the fourth part of this document. Another aspect of the verification of information hiding properties is that it requires to compute the probabilities of the possible outcomes for each scheduler. For this reason, this application quickly turned out to be highly inefficient. However, in an asynchronous system, a lot of transitions are confluent, which means that when evaluating a process, it is only necessary to choose one of the two confluent branches. Hence, I have worked on formalizing the possible optimizations based on the possible confluent computations. This work is presented in the second part of the document. Another interesting aspects of probabilistic protocols is the possibility to con- sider infinite runs. By doing such consideration, it is possible to verify the correction of some probabilistic protocols. For instance, in the case of the Crowds routing protocol, presented in Section 5.3, the protocol is considered correct because the probability of running into an infinite execution is null, hence the message will eventually be delivered. For this reason, I got interested in extending the meaning of a asynchronous probabilistic computations to the case of an infinite execution. As a matter of fact, the combination of infinite computation, confluence and probability is not easy to treat in the general case. The problem of confluence in concurrency is solved in an elegant way in an asyn- chronous paradigm called Concurrent Constraint Programming (CCP). Hence, I decided to study infinite computations in a probabilistic version of CCP. The problem, however, is that the meaning of the result of an infinite probabilistic computation was still an open problem also in that context. Hence, I studied a possible way to define this result, using the notion of valuations and sober spaces, and applied it to give a denotational semantics to probabilistic CCP, including infinite computations. This work is presented in the third part of the document. I have chosen a specific order for the various parts of this document that follows the various formal models that are used, in order to present each result along with the corresponding formalism. * In the first and second parts, I present the formal concurrent models, and in the particular asynchronous ones. * In the third part, I present the probabilistic CCP. This part also presents mathematic structures for the representation of infinite probabilistic executions. * Eventually, an application of both asynchronous and probabilistic models to the case of probabilistic information hiding is presented in the fourth part.

This thesis addresses the three principal questions concerning the development of CT urography for investigating haematuria and each question is the subject of a separate chapter. The questions are: What is the reasoning behind using CT urography? What is the optimum diagnostic strategy using CT urography? What are the problems with using CT urography and how may solutions be provided? Haematuria can signify serious disease such as urinary tract stones, renal cell cancer, upper tract urothelial cancer (UTUC) and bladder cancer (BCa). CT urography is defined as contrast enhanced CT examination of kidneys, ureters and bladder. The technique used here includes unenhanced, nephrographic and excretory-phases for optimized diagnosis of stones, renal masses and urothelial cancer respectively. The reasoning behind using excretory-phase CT urography for investigating haematuria is based on results showing its high diagnostic accuracy for UTUC and BCa. Patients with haematuria are classified as low risk or high risk for UTUC and BCa, by a risk score, determined by the presence/absence of risk factors: age > 50 years, visible or nonvisible haematuria, history of smoking and occupational exposure. The optimum diagnostic strategy for patients at high risk for urothelial cancer, uses CT urography as a replacement test for ultrasonography and intravenous urography and as a triage test for flexible and rigid cystoscopy, resulting in earlier diagnosis and potentially improving prognosis. For patients at low risk, ultrasonography, unenhanced and nephrographic-phase CT urography are proposed as initial imaging tests. Problems with using CT urography include false positive results for UTUC, which are eliminated by retrograde ureteropyelography-guided biopsy, an innovative technique, for histopathological confirmation of diagnosis. Recommendations for the NHS and possible future developments are discussed. CT urography, including excretory-phase imaging, is recommended as the initial diagnostic imaging test before cystoscopy for patients with haematuria at high risk for urothelial cancer.