<p>Introduction: Globally, more than 200 million patients undergo major non-cardiac surgery each year and more than 10 million patients will be exposed to postoperative myocardial ischemia, a condition strongly associated with 30-day mortality. The majority of these events go undetected without postoperative Troponin screening. Methods: We conducted a model-based cost-consequence analysis comparing a postoperative Troponin T screening vs. standard care in patients undergoing noncardiac surgery. In a first model, we evaluated the incremental number of detected perioperative myocardial infarctions and the incremental costs. A second model assessed the effect of the screening and consequent treatment on 1-year survival and the related cost. Model inputs based on the Vascular events In Non-cardiac Surgery patIents cOhort evaluatioN (VISION) Study, a large international cohort. We run probability sensitivity analyses with 5,000 iterations. We conducted extensive sensitivity analyses.</p> <p>Results: The cost to avoid missing an event amounted to CAD$ 5,184 for PMI and CAD$ 2,983 for isolated Troponin T. The cost-effectiveness of the postoperative Troponin screening was higher in patients’ subgroups at higher risk for PMI, e.g. patients undergoing urgent surgery. The incremental costs at 1 year of a postoperative PMI screening by 4 Troponin T measurements were CAD$ 169.20 per screened patient. The cost to prevent a death at 1 year amounted to CAD$ 96,314; however, there was relevant model uncertainty associated with the efficacy of the treatment in the 1-year model.</p> <p>Conclusion: Based on the estimated incremental cost per health gain, the implementation of a postoperative Troponin T screening after noncardiac surgery seems appealing, in particular in patients at high risk for perioperative myocardial infarction. However, decision-makers will have to consider it in terms of opportunity costs, i.e. in relation to the cost-effectiveness of other potential programs within the broader health care context.</p> / Master of Science (MSc)

According to the dominant approach in the theory of vagueness, the nature of the vagueness of an expression ‘F’ consists in its presenting borderline cases in an appropriately ordered series: objects which are neither definitely F nor definitely not F (where the notion of definiteness can be semantic, ontic, epistemic, psychological or primitive). In view of the various problems faced by theories of vagueness adopting the dominant approach, the thesis proposes to reconsider the naive theory of vagueness, according to which the nature of the vagueness of an expression consists in its not drawing boundaries between any neighbouring objects in an appropriately ordered series. It is argued that expressions and concepts which do present this feature play an essential role in our cognitive and practical life, allowing us to conceptualize—in a way which would otherwise be impossible—the typically coarse-grained distinctions we encounter in reality. Despite its strong initial plausibility and ability to explain many phenomena of vagueness, the naive theory is widely rejected because thought to be shown inconsistent by the sorites paradox. In reply, it is first argued that accounts of vagueness based on the dominant approach are themselves subject to higher-order sorites paradoxes. The paradox is then solved on behalf of the naive theory by rejecting the unrestricted transitivity of the consequence relation on a vague language; a family of logics apt for reasoning with vague expressions is proposed and studied (using models with partially ordered values). The characteristic philosophical and logical consequences of this novel solution are developed and defended in detail. In particular, it is shown how the analysis of what happens in the attempt of surveying a sorites series and deciding each case allows the naive theory to recover a "thin" notion of a borderline case.

Thèse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal.

La majorité des adolescents québécois auront consommé une substance psychoactive avant la fin de leurs études secondaires. Parmi les facteurs ayant une influence sur cette consommation, on retrouve les normes sociales, dont les normes descriptives. Ce mémoire vise à évaluer l’impact des normes descriptives du milieu scolaire sur les comportements d’usage de cannabis chez les adolescents québécois, ainsi que sur les méfaits attribués à cette consommation. Cette étude examine les liens entre l’écart de perception de prévalence de consommation de cannabis au sein d’une école et la consommation ainsi que les conséquences attribuées à cet usage par les élèves. De plus, elle examine le rôle modérateur des écarts de perception de la prévalence de consommation sur la progression de la consommation, ainsi que sur le lien entre la consommation de cannabis en secondaire 4 et des conséquences attribuées à cette consommation un an plus tard. Provenant de la Stratégie d’Intervention Agir Autrement, l’échantillon de cette étude est constitué de 1601 élèves suivis de secondaire 2 à secondaire 5. Des analyses de régression logistique multinomiale ont été conduites et ont montré que plus les élèves surestiment la prévalence de consommation de cannabis au sein de leur école, plus ils ont de chance de consommer du cannabis et d’attribuer des conséquences négatives à leur consommation un an plus tard. Les résultats ont également montré un effet modérateur positif de l’écart de perception de la prévalence sur la progression de la consommation de cannabis de secondaire 4 à 5, spécifiquement chez les élèves ayant une faible consommation en secondaire 4. Finalement, les résultats ont montré un deuxième effet modérateur de l’écart de perception de prévalence, celui-ci sur le lien entre la consommation de cannabis en secondaire 4 et l’attribution de conséquences négatives à cette consommation un an plus tard. Précisément, les élèves ayant une faible consommation et qui surestiment la prévalence de consommation de cannabis au sein de leur école auront plus de chance d’attribuer plusieurs méfaits à leur consommation en secondaire 5 que d’en attribuer aucun. Par contre, les élèves ayant une consommation de cannabis élevée en secondaire 4 ne rapportent pas plus ni moins de conséquences selon leur estimation de prévalence. Les implications de ces résultats sont discutées. / Substance use in adolescence is a relatively common behavior. By the end of high school, a majority of Quebec teenagers will have experimented with psychoactive drugs or alcohol. Among the multiple factors influencing substance use are the social norms, namely the descriptive norms. This study evaluates the impact of the misperception of descriptive norms within the school context on marijuana use and its related consequences. Specifically, this study examines the relationship between the misperception of prevalence of cannabis use within a high school and the actual use of marijuana and its attributed related consequences. It also examines the moderating role of misperception of cannabis use prevalence on the progression of marijuana usage, and on the relationship between cannabis use in 10th grade and its attributed consequences a year later. Using data from the New Approaches, New Solutions intervention strategy, 1601 high school students were followed from grade 8 through grade 11. Multinomial logistic regression analyses were conducted and have indicated that the more the students overestimate the prevalence of cannabis use, the more chances they have to use marijuana themselves and attribute negative consequences to their cannabis use a year later. Results have also shown a moderating effect of the misperception of prevalence of cannabis use on the progression of marijuana use from grade 10 to 11, particularly with the students using marijuana occasionally in grade 10. Results also indicate a moderating effect of the misperception of prevalence of school wide cannabis use on the relationship between marijuana use in grade 10 and attributed consequences a year later. Specifically, students using marijuana occasionally and who overestimate the prevalence of cannabis use by their school peers will have more chances of attributing more than three consequences to their drug use in grade 11 than to attribute no harm to it whereas students who use marijuana frequently in grade 10 do not attribute consequences in accordance with their estimation of the prevalence of cannabis use by their school peers. Clinical implications of these findings are discussed.

Syftet med studien var att undersöka låg självkontroll bland män ochkvinnor, utsatthet för brott bland män och kvinnor samt undersöka sambandet mellan låg självkontroll och utsatthet för brott bland unga vuxna. Studien hade en tvärsnittsdesign där en webbenkät skickades ut till en studentpopulation bestående av 159 respondenter (av vilka 83% var kvinnor) i åldrarna 18-25 (M = 22,49, SD = 1,78). Resultatet visade att män hade en lägre självkontroll och att kvinnor hade en högre utsatthet för brott. Resultatet visade även på ett svagt positivt samband mellan låg självkontroll och utsatthet för brott vilket indikerade på att de respondenterna med låg självkontroll var utsatta för brott i högre grad. Resultaten kunde förklaras teoretiskt med Lifestyle Exposure Perspective som antydde att låg självkontroll kunde medföra en högre exponering för riskfyllda situationer vilket i sin tur kunde öka nivån av utsatthet för brott. Dock kan det krävas fler variabler för att förklara sambandet. / The aim of this study was to examine low self-control among men and women, victimization of crime among men and women and examine the correlation between low self-control and the victimization of crime among young adults. The study used a cross-sectional design where a web survey was sent out to a student population consisting of 159 respondents (of which 83% were women) aged 18-25 (M= 22,49, SD=1,78). The result showed that men had lower self-control where as women had higher victimization of crime. The result also showed a weak positive correlation between low self-control and victimization of crime which indicated that the respondents with lower self-control were victimized of crime to a higher degree. The results could be explained theoretically with Lifestyle Exposure Perspective, which implied that low self-control could entail a higher exposure of risk-filled situations which in turn could increase victimization of crimes. It may however be that more variables are required to explain the correlation.

A percepção crescente da sociedade em relação aos perigos inerentes às instalações industriais que manipulam grandes inventários de substâncias perigosas faz com que a ferramenta análise quantitativa de risco ganhe importância na complexa discussão sobre a viabilidade destes empreendimentos, no intuito de promover a ocupação adequada do solo na área urbana e prevenir a ocorrência do chamado acidente maior. Contudo, para se chegar à expressão de risco de uma determinada instalação industrial deve-se aplicar um conjunto de técnicas e de modelos matemáticos, entre os quais estão os modelos de dispersão atmosférica, usados para se estimar a área afetada na vizinhança da mesma por liberações acidentais que levam à formação de nuvens de substâncias químicas na atmosfera. Em decorrência da complexidade inerente ao próprio processo de dispersão atmosférica, especialmente no que tange aos denominados gases densos, existe uma diversidade de modelos que podem ser aplicados no escopo da análise de risco, o que leva a seus usuários, naturalmente, ao questionamento sobre a suscetibilidade dos resultados finais ao tipo de modelagem adotada. Neste sentido, este trabalho estuda o processo de dispersão atmosférica de nuvens densas formadas em liberações acidentais, identificando as principais possibilidades de modelagem deste processo e, ao final, apresenta um estudo de caso demonstrando que diferentes modelagens desta dispersão, comumente empregadas em análise de risco de instalações industriais, podem produzir variações na estimativa do risco de uma mesma instalação e, portanto, influenciar as decisões baseadas em risco. / The concern of the society about the risks posed by activities that deal with hazardous substances has increased in an environment strongly industrialized and with high population density in view of the inherent potential hazards of them as well as the impact of recent accidental episodes, even though their benefits provided. In this context the quantitative risk analysis is presented as an essential tool to assess the risk of these activities and compose a complex discussion about its feasibility. Some of these accident scenarios may involve the formation of a hazardous product cloud and its subsequent air dispersion in the off-site region when an accidental released take place and one should apply the so-called atmospheric dispersion models for estimating the consequences of the releases. Due to the complexity involved in this atmospheric dispersion process, there is a wide variety of mathematical models that can be applied for estimating the offsite consequences of the accidental releases leading, naturally, to one wonder whether the final risk expression of a facility is susceptible to these differences. Often in the world of industrial use of hazardous materials, toxic or flammable there is a possibility that these accidental releases produce clouds that are denser than air, a situation that demands even more attention in terms of risk aspects involved. Then, this dissertation studies the process of atmospheric dispersion of heavier-than-air clouds produced after an accidental release, identifying the main ways of modelling the process and presents a case study comparing different dispersion models that demonstrates that the final expression of risk of a typical installation can be different when it is used different dispersion model in the process.

A doutrina costuma apontar como efeitos dos fatos jurídicos a criação, a modificação ou a extinção de relações jurídicas. Os textos doutrinários normalmente desenvolvem o estudo dos fatos jurídicos que criam relações jurídicas; o presente trabalho, porém, se dedica aos fatos jurídicos tendentes a modificar relações jurídicas anteriormente criadas, restringindo-se ao campo das obrigações. Primeiramente, deve-se buscar um critério: modificação do direito isolado ou da relação jurídica? Como nas relações jurídicas complexas há diversos direitos e deveres recíprocos, a extinção de um direito pode levar apenas à modificação da relação jurídica integralmente considerada. Se Savigny já entendia que um juízo acerca do direito só pode ser verdadeiro quando fundado na compreensão completa da relação jurídica, hoje há renovadas razões para que se adote um critério relacional: a relação obrigacional tem sido vista como um processo, o que leva a um reforço de sua identidade com a inclusão de um elemento finalístico. As ideias de modificação e identidade estão vinculadas, pois, se a \"modificação\" leva à perda da identidade, a relação jurídica na verdade foi extinta. Quanto ao tema das modificações, a maior parte da doutrina parece tratar apenas da \"transmissão das obrigações\". Outros, ao lado dessas modificações subjetivas, tratam de modificações objetivas, normalmente restringindo-se às efetuadas por negócio jurídico. A classificação de Pontes de Miranda, porém, parece servir de referencial para o presente trabalho: quanto às modificações \"sem quebra da identidade da relação jurídica\", o autor aponta modificações negociais, alterações por dolo e culpa, por força maior e caso fortuito, por impossibilidade de adimplemento e, por fim, por mora do devedor e do credor. / Current legal theory generally considers the effects of legal facts (those resulting from the correlation between facts and norms) on the creation, modification or termination of legal relationships. While most authors addresses how legal facts create these relationships, the present study is devoted to legal facts tending to modify the legal relationship, particularly in the field of the Law of Obligations (duty to perform). At first, a criterion must be determined: modification of the isolated right or modification of the Obligation? In \"complex\" obligational relationships, there are many mutual rights and duties, such that the extinction of a right can result only in the modification of the relationship fully considered. Long ago, Savigny asserted that a reasonable analysis of a right must be based on a thorough understanding of the legal relationship at issue. There are now renewed reasons to adopt these relational criteria when analyzing legal relationships. The obligational relationship may be seen as a process, which leads to the reinforcement of its identity with the inclusion of a finalistic element. The ideas of modification and identity are linked, because if a \"change\" leads to the loss of identity, the legal relationship may, in fact, have been terminated. Most of the authors on the subject of modifications addresses the \"transfer of obligations\". Some other studies, beside these subjective modifications, addresses objective modifications, usually restricted to those made by agreement. The \"Pontes de Miranda\" classification, may serve as a useful reference when analyzing the issue of modifications. The author points to modifications by agreement, changes by dolus and culpa (fault, tort law and breach of contract), by force majeure or unforeseeable circumstances, impossibility of performance, and, ultimately, by the mora debitoris and mora creditoris/accipiendi (default, delay of performance) as modifications \"without breaking the identity of the legal relationship\".

Made available in DSpace on 2016-04-29T13:18:17Z (GMT). No. of bitstreams: 1 Virginia Cordeiro Amorim.pdf: 2726224 bytes, checksum: 1fe97f4facc3b2d680c57bba2fb47385 (MD5) Previous issue date: 2010-04-19 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Operant behavior (either social or not) depends upon reinforcement, but it is known that not all instances produce reinforcement. Assuming that cultural consequences are analogous to operant consequences in metacontingencies selection, the purpose of the present study was to answer the following question: what are the effects of the intermittence of cultural consequences on the production of IBCs and their aggregate outcomes ? Three studies were conducted in which undergraduate students distributed in generations of three participants were exposed to a trial procedure. Three participants worked simultaneously, and each was generally called PE, PC and PD. These participants were replaced, one at a time, by successive generations. At each trial 4 numbers were presented to each participant in their own computer screen by software; the numbers were distributed in 4 columns. The task of each participant was to write in 4 columns below each number presented in the screen. Two experimental contingencies were operative: a) individual consequences points - were contingent on 4 odd sums of the numbers presented by the computer and the numbers entered by the participants individually; and b) cultural consequence bonus were contingent on the aggregate outcome (PLE ≤ PLC ≤ PLD): if the sum of the 4 numbers entered by PE was smaller or equal to the sum of the 4 numbers entered by PC, which was smaller or equal to the sum of the 4 numbers entered by PD. The contingencies for the production of individual consequences remained the same in all experiments. In Experiment 1 there were 11 participants distributed in 9 generations and it was verified the effects of the intermittency of the cultural consequence production on the production of IBCs and their aggregate outcomes , after the aggregate product was selected. It was verified that the production of IBCs and its aggregate outcomes was altered after the introduction of the intermittent schedule but this effect was transitory. There were 12 participants over 7 generations in Experiment 2. The experiment s aim was to evaluate the effects of the presentation of cultural consequence intermittently on the production of IBCs and their aggregate outcomes , after the aggregate product was selected. Results showed that the introduction of the intermittency did not immediately affect the production if IBCs and their aggregate outcomes . Experiment 3 had 12 participants and 10 generations. Its aim was to verify the effects of the intermittent production of cultural consequence on the selection of IBCs and its aggregate outcomes . Results showed, once again, that an intermittent cultural consequence is enough to select IBCs and their aggregate outcomes . In general, results showed that 1) cultural consequences produced or presented intermittently are enough to maintain IBCs and their aggregate outcomes , and 2) cultural consequences intermittently produced select IBCs and its aggregate outcomes / O comportamento operante (social ou não) é dependente do reforçamento, mas sabe-se que nem toda instância produz reforço. Uma vez que se supõe que conseqüências culturais têm função análoga à das conseqüências operantes no processo de seleção de/por metacontingências, este trabalho buscou verificar: quais os efeitos da intermitência da conseqüência cultural sobre a produção de CCEs e seus produtos agregados . Foram realizados três experimentos, nos quais universitários distribuídos em gerações de três participantes foram submetidos a um procedimento de tentativas com mudança de gerações. Trabalhavam simultaneamente três participantes designados genericamente PE, PC e PD. Estes participantes foram sendo substituídos um a um por sucessivas gerações. A cada tentativa, um programa apresentava para cada participante independentemente e simultaneamente quatro números, em quatro colunas, na tela do computador de cada um deles. A tarefa de cada participante era inserir quatro números logo abaixo dos números apresentados. Estavam em vigor duas contingências experimentais, nas quais poderiam ser produzidas: a) conseqüência individual pontos - para quatro somas ímpares entre os números apresentados pelo computador e os números inseridos pelo participante individualmente; e b) conseqüência cultural bônus - para o produto agregado PLE ≤ PLC ≤ PLD, quando as somas dos 4 números inseridos por PE era menor ou igual à soma dos 4 números inseridos por PC que eram menor ou igual à soma dos números inseridos por PD. As contingências para produção da conseqüência individual foram as mesmas em todos os experimentos. O Experimento 1 teve 11 participantes ao longo de 9 gerações e verificou os efeitos da intermitência da produção da conseqüência cultural sobre a produção de CCEs e seus produtos agregados previamente selecionados por conseqüências culturais continuamente produzidas. Verificou-se que a produção de CCEs e seus produtos agregados foi alterada após a introdução da intermitência, mas foi retomada ao longo das gerações. O Experimento 2 contou com 10 participantes ao longo de 7 gerações e avaliou os efeitos da intermitência da apresentação da conseqüência cultural sobre a produção de CCEs e seus produtos agregados previamente selecionados por conseqüências culturais continuamente produzidas. Verificou-se que introdução da intermitência não alterou de imediato a produção de CCEs e seus produtos agregados , mas nas gerações seguintes ocorreram oscilações. O Experimento 3 teve 12 participantes ao longo de 10 gerações e verificou os efeitos da intermitência da produção da conseqüência cultural sobre a seleção de CCEs e seus produtos agregados . Verificou-se que a conseqüência cultural intermitente é suficiente para selecionar CCEs e seus produtos agregados . De uma forma geral, pode-se afirmar que: 1) conseqüências culturais produzidas ou apresentadas intermitentemente são suficientes para manter CCEs e seus produtos agregados previamente selecionados por conseqüências culturais continuamente produzidas, e 2) conseqüências culturais produzidas intermitentemente selecionam CCEs e seus produtos agregados

L’objectif de la thèse est d’effectuer l’analyse de sensibilité paramétrique du logiciel Phast de modélisation de la dispersion atmosphérique de gaz toxiques et/ou inflammables. La technique a consisté à coupler Phast et l’outil d’analyse de sensibilité SimLab, ce qui permet d’exécuter automatiquement un grand nombre de simulations en faisant varier l’ensemble des paramètres du modèle de façon simultanée. La méthode d’analyse de sensibilité globale choisie, E-FAST, est basée sur l’analyse de la variance des sorties du modèle pour le calcul des indices de sensibilité. Nous avons étudié des scénarios de rejet continus pour six produits différents (monoxyde d’azote, ammoniac, chlore, azote, n-hexane et fluorure d’hydrogène), sélectionnés pour couvrir une large gamme de caractéristiques physiques et de conditions de stockage. L’analyse du modèle de dispersion de Phast, Unified Dispersion Model, a été séparée en deux étapes : étape de « screening » avec pour but de comparer l’influence de l’ensemble des paramètres puis étude de l’influence globale des paramètres de modélisation, autres que les paramètres météo et du terme source, sur une plage large de valeurs. Pour chaque produit, nous avons décomposé les scénarios de base en sous-scénarios correspondant à des conditions de rejet différentes. Ce travail a notamment permis de classifier les paramètres du modèle selon leur degré d’influence sur la variabilité de différentes sorties et d’effectuer une analyse comparative par produit indiquant, pour des conditions de rejet données, quels paramètres sont les plus influents sur les sorties. Une étude complémentaire a consisté à effectuer une analyse de sensibilité locale de ces paramètres autour de leur valeur par défaut. / We have undertaken a parametric sensitivity analysis of the Phast software tool’s models for atmospheric dispersion of toxic and/or inflammable gases. We have coupled Phast with the sensitivity analysis tool SimLab, and have automated the execution of a large number of simulations while varying simultaneously selected model parameters. The global sensitivity analysis method used, E-FAST, is based on analysis of the variance of model outputs, and allows us to estimate sensitivity indices. We have studied continuous release scenarios for six different products (nitric oxide, ammonia, chlorine, nitrogen, n-hexane and hydrogen fluoride), which were chosen to cover a wide range of physical characteristics and storage conditions. Our analysis of Phast’s Unified Dispersion Model comprises two phases: a screening phase which allows the sensitivity of a wide range of parameters to be compared, followed by a phase focusing on the sensitivity of internal model parameters (excluding weather and source term variables), over a wide input range. For each product, we have broken down base-case scenarios into a number of sub-scenarios corresponding to different release conditions. This work has allowed us to rank model parameters according to their influence on the variability of a number of model outputs. It also includes a per-product comparative analysis indicating, for each release condition studied, which parameters have the most influence on the outputs. In the final part of the work, we have analyzed the local sensitivity of these parameters in a narrow range around their default values.

In this work, a source term model for estimating the rate of spreading and vaporization of LNG on land and sea is introduced. The model takes into account the composition changes of the boiling mixture, the varying thermodynamic properties due to preferential boiling within the mixture and the effect of boiling on conductive heat transfer. The heat, mass and momentum balance equations are derived for continuous and instantaneous spills and mixture thermodynamic effects are incorporated. A parameter sensitivity analysis was conducted to determine the effect of boiling heat transfer regimes, friction, thermal contact/roughness correction parameter and VLE/mixture thermodynamics on the pool spreading behavior. The aim was to provide a better understanding of these governing phenomena and their relative importance throughout the pool lifetime. The spread model was validated against available experimental data for pool spreading on concrete and sea. The model is solved using Matlab for two continuous and instantaneous spill scenarios and is validated against experimental data on cryogenic pool spreading found in literature.