Biomphalaria glabrata est un mollusque d’eau douce, vivant en Amérique latine. Ce planorbe est principalement connu pour être l’hôte intermédiaire de Schistosoma mansoni, vers plat parasite responsable de la bilharziose intestinale, seconde endémie parasitaire humaine mondiale derrière le paludisme.Dans ce contexte, il apparaît clairement qu’une meilleure compréhension de l’interaction entre le parasite et le mollusque, hôte intermédiaire, représente une voie de recherche prometteuse. La compréhension des interactions immunologiques entre l’escargot et le parasite ainsi que des mécanismes moléculaires par lesquels les deux partenaires interagissent apparaît comme un pré-requis à la découverte de nouvelles cibles ou de nouvelles stratégies afin de développer desmoyens de lutte contre le pathogène.Le projet de cette thèse s’inscrit dans cette optique et vise à une meilleure compréhension des interactions immunologiques entre le mollusque Biomphalaria glabrata et le trématode Schistosoma mansoni. Différents aspects de l’interaction entre B.glabrata et S.mansoni ont été explorés, des bases moléculaires et cellulaires à l’interaction tripartite entre l’immunité du mollusque, son microbiote et le pathogène. Dans un premier temps nous avons pu démontrer ungradient d’infectivité des parasites et de susceptibilité des mollusques de différents provenances géographiques. De plus, l’interaction immunologique entre le mollusque et le parasite est supportée par une adaptation locale, à l’échelle moléculaire. Nous avons également pu montrer qu’une opsonine, la BgTEP, jouait un rôle clé dans l’interaction entre B.glabrata et ses différents pathogènes. Enfin, l’existence d’une véritable interaction tripartite entre la réponse immunitaire du mollusque, son microbiote et son parasite a pu être mise en évidence. / Biomphalaria glabrata is tropical fresh water snail, living in Latin America. This planorbe is the intermediary host of Schistosoma mansoni, a trematode responsible for the intestinal Schistosomiasis, second worldwide human vector-borne disease after the malaria. In this context, a better comprehension of the parasite/snail interaction is necessary and appearsa promising research field. The understanding of immunological interaction between the host and the parasite and the molecular mechanisms used by the two partners appears like essential for the discovery of new targets and new strategies in order to develop means of struggle against the pathogen. The aim of this thesis is to better understand the immunological interactions between the B. glabrata snail and S. mansoni trematode. Different aspects of the interaction between the snail and the parasite have been explored, from molecular and cellular bases to the tripartite interaction between the snail immunity, its microbiota and the pathogen. In a first step we have been able to demonstrate a gradient of parasite infectivities and snail susceptibilities from different geographical origins. Moreover, the immunological interaction between B. glabrata and S. mansoni is supported by local adaptation, at the molecular level. We were also able to show than an opsonin, the BgTEP, plays a key role in the interaction between B. glabrata and its various pathogens. Finally, the existence of a true tripartite interaction between the snail immune response, its microbiota and its parasite could was demonstrated.

Le glutamate est le principal neurotransmetteur excitateur du système nerveux central des vertébrés, et le codage de l’information cérébrale repose en partie sur des modulations de l’amplitude et de la fréquence des transmissions synaptiques glutamatergiques. De ce fait, la résolution spatiale et temporelle de ces transmissions nécessite un contrôle fin de la présence de glutamate dans la fente synaptique. Cette durée de vie du glutamate dans les synapses dépend directement de l’action de transporteurs spécifiques exprimés à la surface des astrocytes, en particulier les transporteurs de type GLT-1, qui retirent le neurotransmetteur et permettent ainsi de « nettoyer » la fente synaptique avant la survenue d’un nouvel épisode de neurotransmission. / A classic understanding of neurotransmitter clearance at glutamatergic synapses is that, in order to ensure sufficient glutamate uptake on a fast timescale, it is necessary to have high numbers of glutamate transporters in the vicinity of release sites to compensate for their slow transport kinetics. Using a combination of single molecule imaging and electrophysiological approaches, we now challenge this view by first demonstrating that GLT-1 transporters are not static but highly mobile at the surface of astrocytes, and that their surface diffusion is dependent upon both neuronal and glial cell activities. In the vicinity of glutamate synapses, GLT-1 dynamics are strongly reduced favoring their retention within this strategic location. Remarkably, glutamate uncaging at synaptic sites instantaneously increases GLT-1 diffusion, displacing the glutamate-bound transporter away from this compartment. Functionally, impairment of the transporter lateral diffusion through an antibody-based surface cross linking, both in vitro and in vivo, significantly slows the kinetics of excitatory postsynaptic currents. Taken together, these data reveal the unexpected and major role of the astrocytic surface GLT-1 fast dynamics in shaping glutamatergic synaptic transmission.Keywords:

The impact of deceased tissue donation and transplantation is far-reaching; however, little is known about the public’s attitudes towards tissue donation. Siminoff, Traino, and Gordon (2010) found that families’ attitudes towards tissue donation were a significant predictor of consent; specifically, families that were initially favorable towards tissue donation were more likely to donate their loved ones tissues than families that were initially unfavorable towards tissue donation. Using a qualitative coding approach and the Tripartite Model of Attitude Structure (affective, behavioral, and cognitive attitude components) as a conceptual framework, families’ expressed attitudes toward tissue donation were extracted from N=240 audiorecordings of past tissue donation requests from 16 different OPOs. In addition, semi-structured interviews were conducted with N=14 Tissue Requesters from LifeNet Health in Virginia Beach, Virginia about their perceptions of families’ attitudes. Together, 14 attitude domains and 34 subdomains were derived from the families’ expressed attitudes. Several multivariate analyses were performed. After controlling for time spent discussing tissue donation and confusion between tissues and organs, affective attitudes were significantly different among three FDM initial response groups (favorable, unsure, and unfavorable). Further, the attitude domains “donation invokes positive emotion” and “pro-donation behaviors” were the best discriminators of FDM groups. Suggestions for educational interventions were discussed.

The current project involved three studies designed to examine which characteristics of persuasive communications change condom use attitudes. Study 1 investigated the effect of message type (affective versus cognitive) and source (male versus female) on attitude change among a sample of African American women attending college. In Study 1 (N = 146), the affective message and female source produced the most positive change in condom use attitudes. Study 2 examined whether message type and source were associated with favorable condom attitudes in a community sample and whether these findings differed from a college sample. Twenty-seven women participated in group discussions and completed measures of attitudes and intentions. Similar to Study 1, the pattern of means in Study 2 showed the affective message delivered by the female source resulted in the most positive condom use attitude change. These results were not significant likely due to the small sample. Focus groups were also conducted to better understand the types of condom use messages African American women find effective. Several themes emerged: condom used primarily for pregnancy prevention; negative condom use attitudes; communicating messages through internet, TV, and radio; creating fun, catchy, and informative messages; using celebrities and peers to deliver messages; and increasing the frequency of messages to equal importance of topic. The third study assessed the effectiveness of an attitude change pilot intervention that was based on the results of Studies 1 and 2. The study used a 2 (intervention vs. control) X 3 (pretest, posttest, follow-up) mixed factorial design to examine whether women’s attitudes changed after a pilot session and whether the change persisted over time. African American women (N = 115) were recruited through Craigslist and community agencies. There were no significant differences across time for the intervention and the control group. Reasons for the lack of an effect in Study 3 are discussed. Taken together, these studies provide evidence that, under certain conditions an affective message delivered by a female source can change attitudes toward using condoms. The results of these studies could potentially enhance existing interventions by renewing a focus on changing attitudes as well as behavior.

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

Esta pesquisa trata do artista suíço Max Bill e sua obra Unidade Tripartida, ganhadora do prêmio de escultura na Primeira Bienal de São Paulo, em 1951. Analisa arquivos referentes a curadorias de exposições em museus, aliados a informações sobre o percurso nacional e internacional da escultura tridimensional Unidade Tripartida e do artista Max Bill. Sua trajetória, desde o entendimento de sua produção até a sua formação, com participação na escola Bauhaus e a formação da Escola de Ulm, em que desenvolveu a teoria que sustentou a arte concreta, abrange diversas áreas do conhecimento artístico no decorrer das décadas de quarenta e cinquenta do século XX. O estudo aponta, também, as influências das ideias de Bill na produção concreta e neoconcreta de artistas brasileiros. / The following essay is about the Swiss artist Max Bill and his work Tripartite Unity (Unidade Tripartida), winner of the Sculpture Prize at the First Biennial of São Paulo, in 1951. Analyzes files relating to curtained exhibitions in museums, within information about national and international course of the three-dimensional sculpture Tripartite Unity and about the artist Max Bill. Its history, from the understanding of its production to its formation, with participation at the Bauhaus school and the formation of the School of Ulm, in which he developed the theory that supports the concrete art, covers several areas of artistic knowledge during the forties and fifties. The thesis also indicates the influence of Bills ideas in concrete, neo-concrete production on Brazilian artists.

Estudamos o emaranhamento quântico de estados puros emaranhados tri-partidos quando uma das partes é um qubit. Apresentamos um método para encontrar as decomposições do estado tri-partido mais simples do que sucessivas decomposições de Schmidt. Esse método permite encontrar uma grande quantidade de diferentes famílias de estados emaranhados tri-partidos. Essas famílias são classificadas de acordo com dimensão dos blocos de Jordan de uma matriz obtida do estado emaranhado. Além disso, também demonstramos que estados pertencentes a famílias distintas não podem ser convertidos um no outro por operações locais estocásticas com comunicação clássica (SLOCC). No caso de dois estados pertencentes à mesma família, obtemos condições necessárias e su cientes para sabermos se estes podem ser convertidos um no outro por SLOCC. No caso de serão, também podemos obter a operação do tipo SLOCC que realiza a conversão. / We study the quantum entanglement of tripartite pure states when one of the parties is a qubit. We present a method to find the decompositions of tripartite entangled states which are simpler than two successive Schmidt decompositions. We will find many distinct families of entangled states with distinct decompositions. These families are classified according to the dimensions of the Jordan blocks of a matrix obtained from the entangled state. Furthermore, we show that states belonging to distinct families can not be converted into each other by stochastic local operations and classical communication (SLOCC). In case of two states belonging to the same family, we nd necessary and su?cient conditions to convert one state to the other. We can also find the SLOCC which realizes this conversion.

The Stress and Coping Cyclical Amplification Model of Perfectionism in Illness posits, that in the context of a chronic illness, both perfectionistic strivings and concerns contribute to poor health outcomes. Similarly, person-centred models, such as the tripartite model of perfectionism, claim that high levels of both perfectionism concerns and strivings reflect an “unhealthy” perfectionism that takes a toll on well-being. To date there are few comparative tests of these models for physical and mental health outcomes in healthy versus chronically ill individuals. The aim of the current study was to investigate the implications of perfectionism for health by testing how within-person combinations of perfectionism varied in relation to health outcomes, and between fibromyalgia patients (n = 89) and healthy controls (n = 123). Supporting both models, within-person combinations of high perfectionistic strivings and concerns were associated with high stress and poor mental and physical health compared to other within-person combinations. These links were more robust for fibromyalgia patients compared to controls, and stress mediated the association with physical health outcomes only for the fibromyalgia patients. Findings support the value of taking a person-centred approach for understanding how perfectionistic strivings contributes to poor health in the context of chronic illness.

Body image dissatisfaction at moderate levels can be a normative experience for many women of current American culture. However, women whose body dissatisfaction exceeds moderate levels are vulnerable to developing an eating disorder. Empirical findings show body dissatisfaction predicts low self-esteem, depression, and overall poor quality of life. Various theories aim to understand factors involved in the development and maintenance of body dissatisfaction. Sociocultural factors, such as peers, family, and media, have gained the greatest empirical support. The tripartite influence model of body image dissatisfaction and eating disturbance integrates sociocultural factors, and has been empirically tested to evaluate risk factors using an established theoretical model. However, this model has primarily been applied to Caucasian samples. A recent trend in the body image literature is increasing attention to ethnic differences in body image. Jews are an ethnic minority who has been virtually ignored in the empirical literature on body image; yet, studies suggest Jewish females experience body dissatisfaction. To date, no published empirical study has applied the tripartite influence model to Jewish American females. A sociocultural model can potentially increase understanding of body dissatisfaction among Jewish American females. This study used the tripartite influence model to examine relationships among variables (Jewish identity, parental influence, internalization of appearance) hypothesized to relate to body image dissatisfaction. Participants were 255 self-identified Jewish American women who completed a web-based survey measuring these constructs. Results showed a significant, yet weak, relationship between Jewish identity and body dissatisfaction. Contrary to prediction, Jewish women perceived greater pressure from fathers to lose weight than mothers, and no difference in pressure from both parents to gain weight and gain muscle. As perceived pressure from fathers to lose weight increases, women reported greater body dissatisfaction. A significant but weak relationship was found between perceived pressure from fathers to gain muscle and body dissatisfaction. The more women internalize media messages promoting the thin ideal for women, women reported less body satisfaction. A significant but low correlation was found between women who endorsed the "toned," athletic body ideal and body dissatisfaction.

The cutwidth of different graphs is a topic that has been extensively studied. The basis of this paper is the cutwidth of complete n-partite graphs. While looking at the cutwidth of complete n-partite graphs, we strictly consider the linear embedding and cyclic embedding. The relationship between the linear cutwidth and the cyclic cutwidth is discussed and used throughout multiple proofs of different cases for the cyclic cutwidth. All the known cases for the linear and cyclic cutwidth of complete bipartite, complete tripartite, and complete n-partite graphs are highlighted. The main focus of this paper is to expand on the cyclic cutwidth of complete tripartite graphs. Using the relationship of the linear cutwidth and cyclic cutwidth of any graph, we find a lower bound and an upper bound for the cyclic cutwidth of complete tripartite graph K_(r,r,pr) where r is odd and p is a natural number. Throughout this proof there are two cases that develop, p even and p odd. Within each case we have to consider the cuts of multiple regions to find the maximum cut of the cyclic embedding. Once all regions within each case are considered, we discover that the upper and lower bounds are equivalent. This discovery of the cyclic cutwidth of complete tripartite graph K_(r,r,pr) where r is odd and p is a natural number results in getting one step closer to finding the cyclic cutwidth of any complete tripartite graph K_(r,s,t).