L'hormonothérapie permet une régression du cancer de la prostate métastatique par apoptose des cellules tumorales. L'évolution inéluctable de la maladie vers un stade hormono-indépendant et apoptose-résistant souligne l'importance de l'étude des gènes androgéno-sensibles impliqués dans l'apoptose de la prostate normale et pathologique, tels que le ligand TRAIL et ses récepteurs DR4 et DR5 pro et, DcR1 et DcR2 anti-apoptotiques.<br />Nous rapportons une corrélation entre la régulation du récepteur DcR2, le statut hormonal et l'apoptose dans la prostate de rat et dans la lignée humaine hormonosensible de cancer prostatique, LNCaP. Nous montrons que l'expression de DcR2 joue un rôle régulateur de l'apoptose TRAIL-induite dans la cellule LNCaP. Enfin, dans un modèle de cancer prostatique humain hormonosensible greffé chez la souris nude traitée par un anti-androgène nous montrons l'expression des récepteurs au TRAIL, et de certains gènes renseignant sur la relation entre croissance tumorale et statut hormonal.

Urban greenway trails are emerging as potential tourist attractions in cities and are well recognized for their recreation opportunities in general. The study presented an opportunity to expand the scope of aesthetic response research into the realm of urban greenway trails. The concept of likability (Nasar, 1998) was used as a guiding concept in the study. In order to gather data for the study, a web-based virtual tour was developed and implemented. Treatments were assigned to 6 groups that viewed two urban greenway trail corridors. Each trail had three treatments including the existing trail condition, a manipulated trail condition, and a reverse in direction of the existing trail condition. Analyses were conducted to 1) identify dimensions of aesthetic responses, 2) examine relationships between cognitive evaluation, affective response, trail characteristics, and likability, and 3) evaluate specific greenway trail characteristics and their relationships to the trail experience. Results indicated five aesthetic dimensions of the greenway trail corridors. The cognitive dimensions were maintenance, distinctiveness, and naturalness and the affective dimensions were pleasantness and arousal. Pleasantness and distinctiveness were the strongest predictors of likability in urban greenway trails. In terms of greenway trail characteristics, six of eight specific characteristics had predictive value in relation to how inviting the virtual trail was to the viewer. Finally, several greenway trail characteristics had significant influences on human perception and the likability of trail environments. This study proposed a new way of conceptualizing likability and a model of relationships leading to likability. One of the major implications of this study is to identify a way to improve physical conditions of greenway corridors in urban areas based on aesthetic responses. The study also implied that greenways can encompass natural or man-made features and can be managed and developed as a tourist attraction while providing local opportunities in cities. Aesthetic quality influences perceived quality of life and sense of well-being. Findings of the study can help enhance the aesthetic quality of the greenway trails that can contribute to sustainable development in various tourism and recreation settings.

It is the aim of this dissertation to discuss the creation of historiographic space in the works of Francis Parkman. More specifically, this dissertation intends to analyze Parkman’s The Oregon Trail and Montcalm and Wolfe as literary texts that examine geographies of cultural interaction and transnational empire building. Parkman’s historical narratives, this dissertation suggests, not only describe historically significant sites, such as the Oregon Trail and the Northern Frontier, but further create literary heterotopias. These textual counter geographies, as for instance his conceptualizations of the trading posts of the far West and the wilderness fortifications of the far North, allow Parkman to effectively interrogate American history. By investigating the fruitful juncture between history, geography, and literature this project aims to establish the importance of historical geographies for Francis Parkman’s methodology and define its function for the creation of a national consciousness. In addition to Parkman’s use of space, this dissertation further analyzes the historian’s depiction of historical characters and his subsequent attempts to define American identity. Thereby, my analysis specifically highlights the relationship between Parkman’s literary characters and their environment. In an attempt to trace the impact Parkman’s historical narratives exert on postmodern authors of American literature, the concluding chapters interrogate the re-negotiation of Parkman’s historiographic spaces in Thomas King’s Truth and Bright Water and William T. Vollmann’s Fathers and Crows.

Rooted in a critical dialogue that endeavours to theorize experience in contrast to the colonial impetus, this dissertation explores the lived experience of Appalachian Trail thru-hikers. As a result of this disposition, the purpose of this dissertation is to expose the dynamics associated with colonized experiences and empirically research the lived experience of thru-hikers from an ecophenomenological perspective. The subsequent approach views the activities of the lived human body as the process through which the world comes into being. Building on Merleau-Pontian phenomenology, ecophenomenology provides the foundation of the experiential self, and thus underlies the representation of the trail environment as a sensuous field of human activity where one is merged with one's socio-ecological surroundings. Explication of empirical materials from 27 participant interviews resulted in a wide range of thru-hiking experiences representing the operative essence of Appalachian Trail thru-hiking. The operative essence was identified across 4 broad dimensions: Perseity, Sojourning, Kinship, and Wild Imbrication. Each dimension comprised a dialectic which emerged from interview excerpts both congruent with and in contrast to wilderness ideology. Further exploration of wilderness ideals resulted in thru-hikers negotiating tensions related to ideological wilderness meanings and their own actual thru-hiking experiences. This negotiation allowed a broader conception of wilderness to be illustrated as a continuum of meaningful experiences. In addition, ecoliteracy emerged as an experientially driven learning process whereby thru-hikers negotiate alternative meanings of wilderness with ideological meanings. The implications for experiential and wilderness related research along with management concerns are discussed.

In addition to their original purpose as recreational areas, urban parks provide important habitats for species living in urban settings. Reconciling recreational and environmental goals is problematic, especially for park planners. RIM Park, in Waterloo, Ontario, is an example of this attempted reconciliation, where planners and managers attempted to conserve herpetofauna in a provincially significant wetland. However, this area includes a paved nature trail used by hikers, in-line skaters and cyclists and is adjacent to a golf course (which lies within the boundaries of the park). Herpetofauna breeding ponds were constructed and a series of culverts and clearspans included in order to provide reptiles and amphibians with safe passage under the trails. My objective was to determine whether these measures have been effective, whether the park sustains a viable population of Northern Leopard Frogs, and what factors influence frog populations in the park. Two spring field seasons involving mark and recapture techniques were attempted to estimate population sizes of Northern Leopard Frogs at RIM Park, as well as control sites. In both seasons, a control site was a cedar swamp 14 km to the west of the park within an Environmentally Sensitive Policy Area in Waterloo city limits affected by housing development and shared trails. Also within Waterloo city limits, a storm water management pond 8 km to the west was added in field season two. In 2005 (field season 1), because there was a serious drought almost no Northern Leopard Frogs were captured at the two sites examined ? RIM Park and the cedar swamp. In 2006, the more "normal" weather conditions revealed that RIM Park had significantly fewer Northern Leopard Frogs than either of the control sites. Given the lack of data in year 1, I compared the 2006 results to seven years of monitoring reports on RIM Park from consultants. The 2006 data were consistent with previous reports of small Northern Leopard Frog populations at RIM Park. Mark and recapture sessions revealed relatively low numbers, with a catch average of 4. 33 (SD = 1. 15). Calculations revealed an estimated population of 23 (SE = 13. 42). The highest number of observed Northern Leopard Frogs ever recorded at the same location in consulting reports is 5. It is likely that the ponds at RIM Park do not support breeding in Northern Leopard Frogs as the only adults caught were late in the season, during the last week of May, and adults likely were transients from the nearby wetlands and uplands. It is possible, given the historical monitoring data, that the Northern Leopard Frogs were long absent from RIM Park because of intensive farming activities that had replaced the wetlands, and that construction of the golf course and trails further precluded colonization. The lack of adult frogs in the breeding ponds and the lack of dead or injured frogs on the trails or golf course support the hypothesis that the trails are not presently causing frog mortality. It is possible that the frogs are avoiding recolonizing the trail and golf course area. It is also likely that the breeding ponds need to be deepened and only then will it be apparent whether the frogs will colonize the ponds, lay eggs, and use the clearspans and culverts. Recommendations include a shift in priorities to put the emphasis on restoration, a discussion of restoration options (including a possible restoration plan), possible improvements in amphibian monitoring techniques (such as reducing the reliance on audio methods), and general suggestions for urban park planning and management.

Rooted in a critical dialogue that endeavours to theorize experience in contrast to the colonial impetus, this dissertation explores the lived experience of Appalachian Trail thru-hikers. As a result of this disposition, the purpose of this dissertation is to expose the dynamics associated with colonized experiences and empirically research the lived experience of thru-hikers from an ecophenomenological perspective. The subsequent approach views the activities of the lived human body as the process through which the world comes into being. Building on Merleau-Pontian phenomenology, ecophenomenology provides the foundation of the experiential self, and thus underlies the representation of the trail environment as a sensuous field of human activity where one is merged with one's socio-ecological surroundings. Explication of empirical materials from 27 participant interviews resulted in a wide range of thru-hiking experiences representing the operative essence of Appalachian Trail thru-hiking. The operative essence was identified across 4 broad dimensions: Perseity, Sojourning, Kinship, and Wild Imbrication. Each dimension comprised a dialectic which emerged from interview excerpts both congruent with and in contrast to wilderness ideology. Further exploration of wilderness ideals resulted in thru-hikers negotiating tensions related to ideological wilderness meanings and their own actual thru-hiking experiences. This negotiation allowed a broader conception of wilderness to be illustrated as a continuum of meaningful experiences. In addition, ecoliteracy emerged as an experientially driven learning process whereby thru-hikers negotiate alternative meanings of wilderness with ideological meanings. The implications for experiential and wilderness related research along with management concerns are discussed.

Wayfinding is a complex skill and the lack of tools supporting the specific sub-types of navigation hinders performance in large-scale virtual environments and consequently can slow the adoption of virtual technology for training. The VTrail System is designed to support virtual training by providing trainers (trailblazers) with the ability to create trails to guide users (trail followers) during training simulations. Without an effective interface to assist with creating trails, the task of trailblazing remains difficult. The objective of this research was to design a default interface for the VTrail System that adheres to the basic human factors engineering guidelines of simplicity, universality, and that does not interfere with primary task performance. Two studies (trailblazing, trail following), with a total of four experiments, were performed to evaluate and modify the proposed interfaces. The first experiments in each study determined that the proposed default interfaces are simple enough to use so as to not interfere with primary task performance. The second set of experiments found that, aside from the interface components included in the default interface, novice trailblazers and trail followers did not make use of any additional wayfinding aids when users were provided with the ability to create a custom interface. Secondary benefits included; the development of a novel approach for measuring spatial knowledge acquisition (called the SKAT), a set of criteria for qualitative analysis of trail quality in the form of the Trail Quality Questionnaire (referred to as TQQ), and improved understanding of the role individual differences, such as gender and spatial ability, in wayfinding performance. The high correlation between spatial ability score and performance on the SKAT suggests that the test provides a valid means of measuring spatial knowledge acquisition in a virtual environment. A measurable difference in the trail quality between males and females indicates that the TQQ can distinguish between trails of variable quality. Finally, there are measurable gender performance differences, despite similar levels in spatial ability between the genders. With the proposed interface designs the VTrail is closer to being ready to be incorporated as a support tool into virtual training programs. In addition, the designs for the VTrail System can be adapted for other platforms to support trailblazing in a range of applications, from use in military operations to providing an enhanced tourism experience. This research also serves as a starting point for future research projects on topics ranging from improving the design of the SKAT measure to understanding the effect of expertise on trailblazing performance.

The problem of scheduling a parallel program presented by a weighted directed acyclic graph (DAG) to the set of homogeneous processors for minimizing the completion time of the program has been extensively studied as academic optimization problem which occurs in optimizing the execution time of parallel algorithm with parallel computer.In this paper, we propose an application of the Ant Colony Optimization (ACO) to a multiprocessor scheduling problem (MPSP). In the MPSP, no preemption is allowed and each operation demands a setup time on the machines. The problem seeks to compose a schedule that minimizes the total completion time.We therefore rely on heuristics to find solutions since solution methods are not feasible for most problems as such. This novel heuristic searching approach to the multiprocessor based on the ACO algorithm a collection of agents cooperate to effectively explore the search space.A computational experiment is conducted on a suit of benchmark application. By comparing our algorithm result obtained to that of previous heuristic algorithm, it is evince that the ACO algorithm exhibits competitive performance with small error ratio.

In addition to their original purpose as recreational areas, urban parks provide important habitats for species living in urban settings. Reconciling recreational and environmental goals is problematic, especially for park planners. RIM Park, in Waterloo, Ontario, is an example of this attempted reconciliation, where planners and managers attempted to conserve herpetofauna in a provincially significant wetland. However, this area includes a paved nature trail used by hikers, in-line skaters and cyclists and is adjacent to a golf course (which lies within the boundaries of the park). Herpetofauna breeding ponds were constructed and a series of culverts and clearspans included in order to provide reptiles and amphibians with safe passage under the trails. My objective was to determine whether these measures have been effective, whether the park sustains a viable population of Northern Leopard Frogs, and what factors influence frog populations in the park. Two spring field seasons involving mark and recapture techniques were attempted to estimate population sizes of Northern Leopard Frogs at RIM Park, as well as control sites. In both seasons, a control site was a cedar swamp 14 km to the west of the park within an Environmentally Sensitive Policy Area in Waterloo city limits affected by housing development and shared trails. Also within Waterloo city limits, a storm water management pond 8 km to the west was added in field season two. In 2005 (field season 1), because there was a serious drought almost no Northern Leopard Frogs were captured at the two sites examined ? RIM Park and the cedar swamp. In 2006, the more "normal" weather conditions revealed that RIM Park had significantly fewer Northern Leopard Frogs than either of the control sites. Given the lack of data in year 1, I compared the 2006 results to seven years of monitoring reports on RIM Park from consultants. The 2006 data were consistent with previous reports of small Northern Leopard Frog populations at RIM Park. Mark and recapture sessions revealed relatively low numbers, with a catch average of 4. 33 (SD = 1. 15). Calculations revealed an estimated population of 23 (SE = 13. 42). The highest number of observed Northern Leopard Frogs ever recorded at the same location in consulting reports is 5. It is likely that the ponds at RIM Park do not support breeding in Northern Leopard Frogs as the only adults caught were late in the season, during the last week of May, and adults likely were transients from the nearby wetlands and uplands. It is possible, given the historical monitoring data, that the Northern Leopard Frogs were long absent from RIM Park because of intensive farming activities that had replaced the wetlands, and that construction of the golf course and trails further precluded colonization. The lack of adult frogs in the breeding ponds and the lack of dead or injured frogs on the trails or golf course support the hypothesis that the trails are not presently causing frog mortality. It is possible that the frogs are avoiding recolonizing the trail and golf course area. It is also likely that the breeding ponds need to be deepened and only then will it be apparent whether the frogs will colonize the ponds, lay eggs, and use the clearspans and culverts. Recommendations include a shift in priorities to put the emphasis on restoration, a discussion of restoration options (including a possible restoration plan), possible improvements in amphibian monitoring techniques (such as reducing the reliance on audio methods), and general suggestions for urban park planning and management.

Wayfinding is a complex skill and the lack of tools supporting the specific sub-types of navigation hinders performance in large-scale virtual environments and consequently can slow the adoption of virtual technology for training. The VTrail System is designed to support virtual training by providing trainers (trailblazers) with the ability to create trails to guide users (trail followers) during training simulations. Without an effective interface to assist with creating trails, the task of trailblazing remains difficult. The objective of this research was to design a default interface for the VTrail System that adheres to the basic human factors engineering guidelines of simplicity, universality, and that does not interfere with primary task performance. Two studies (trailblazing, trail following), with a total of four experiments, were performed to evaluate and modify the proposed interfaces. The first experiments in each study determined that the proposed default interfaces are simple enough to use so as to not interfere with primary task performance. The second set of experiments found that, aside from the interface components included in the default interface, novice trailblazers and trail followers did not make use of any additional wayfinding aids when users were provided with the ability to create a custom interface. Secondary benefits included; the development of a novel approach for measuring spatial knowledge acquisition (called the SKAT), a set of criteria for qualitative analysis of trail quality in the form of the Trail Quality Questionnaire (referred to as TQQ), and improved understanding of the role individual differences, such as gender and spatial ability, in wayfinding performance. The high correlation between spatial ability score and performance on the SKAT suggests that the test provides a valid means of measuring spatial knowledge acquisition in a virtual environment. A measurable difference in the trail quality between males and females indicates that the TQQ can distinguish between trails of variable quality. Finally, there are measurable gender performance differences, despite similar levels in spatial ability between the genders. With the proposed interface designs the VTrail is closer to being ready to be incorporated as a support tool into virtual training programs. In addition, the designs for the VTrail System can be adapted for other platforms to support trailblazing in a range of applications, from use in military operations to providing an enhanced tourism experience. This research also serves as a starting point for future research projects on topics ranging from improving the design of the SKAT measure to understanding the effect of expertise on trailblazing performance.