Background: Photothermal therapy is an actively researched cancer treatment alternative to chemotherapy and resection due to its potential as a minimally invasive treatment with fewer health complications than high energy radiation therapies. The effectiveness of photothermal therapy may be enhanced with the use of photoabsorbtive nanoparticles by increasing heat generation and improving spatial selectivity. While photothermal therapy is a spatially distributed treatment, traditional experimental analysis methods used to assess photothermal therapy have either lacked spatial assessment such as is the case with standard viability assays of cell monolayers, or they only provide macroscopic treatment information, such as the measurement of the diameters of implanted mice flank tumors post-treatment. Goals: This work aims to accomplish two major goals. The first is to determine the therapeutic impact of combining Single Walled Carbon Nanohorns (SWNHs) with photothermal therapy. The second is to advance the measurement tools used to assess photothermal therapy by developing viability measurement methods which incorporate detailed quantitative spatial information Methods: Photothermal therapy was tested with and without SWNHs in in vitro cell monolayers, in vitro tissue phantoms, and ex-vivo tissue. Digital image analysis methods were developed which allowed for the use of viability assays and histological information to be identified and organized spatially. These methods were then used to compare the impact of cellular microenvironment and heating method on Arrhenius parameters. Results: The inclusion of SWNHs dramatically increased the temperatures reached in each experiment. Digital image analysis methods were shown to quantify spatial viability with a high degree of accuracy and precision in 2D and 3D. Experimental data indicated that there were areas of collateral damage (partially treated tissue) surrounding areas of completely treated tissue ranging which were between 46% and 78% of the completely treated volume. In each case the heat transfer properties of the experimental system had a large impact on the area of treatment. Variation in the temperature and viability response of photothermal therapy for specific laser and nanoparticle treatment parameters was quantified. Conclusions: This research has brought an experimental cancer treatment procedure from experiments in cell monolayers to tests in ex-vivo tissue to analyze viability response. The strengths of photothermal therapy such as its minimally invasive nature, and effectiveness at killing cells were experimentally demonstrated. This research has also developed the tools necessary to assess the spatial impact in vitro and lay the foundations for assessing spatial impact in vivo. These tools may be used to assess other treatments beyond photothermal therapy, and serve as a basis for improving the analysis of biological systems both in vitro and in vivo. / Ph. D.

We sampled forest stands in upland forests of the Southeastern US along a chronosequence of a replicated successional forest sere (1, 6, 10, 25, and 80 years) to elucidate the temporal changes in soil spatial heterogeneity. Samples were collected from loblolly pine plantations representing reorganization through aggradation phases of succession, and from one set of oak-hickory stands to signify the steady-state phase of the model. These trends are characterized and compared to a conceptual model of pattern dynamics. Variability in soil properties (NO3, NH4, pH, Total N, Total C) and forest floor litter at scales relevant to individual plants was quantified using univariate and geostatistical procedures. Global variation (using both coefficient of variation and standard deviation), patch size and proportion of spatially structured variation were examined for individual variables at each successional stage. These patterns were also averaged to produce a generalized model of spatial heterogeneity change during succession. Individual variables often showed differing patterns. However, when patterns from individual variables were averaged, overall patterns emerged. Early in succession global variability was largest and patch sizes were smallest. As succession progressed, trends in the data showed that global variability decreased and patch sizes increased to the middle stage of succession. Both of these trends fit our conceptual model of pattern dynamics. However, the slopes in these trends were not significant at alpha=0.05. / Master of Science

Across the U.S., wildfires have become increasingly destructive and costly over the past few decades, with impacts particularly severe in the State of Florida. Because of an increase in wildfire frequency and severity and the number of people living in fire-prone areas the issue of wildfire risk management is of growing significance. One of the most important wildfire risk reduction tools is prescribed fire to reduce fuel loads, thereby reducing wildfire intensity and resulting damages. Because fire moves across a landscape and ownership boundaries, the spatial pattern of fuel load reduction may influence individual landowners' decisions about fire risk management on their own property. We develop and empirically test a spatial econometric model to study the interaction between Florida landowners in their wildfire risk management decisions. / Master of Science

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Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

The geography subject in Swedish upper secondary school is in a marginalized position with just two national programs having it as a mandatory subject. No mention of the skill of spatial thinking is made in the regulation documents from the Swedish National Agency for Education. To investigate the spatial thinking in the Swedish upper secondary school, I constructed a test that 140 students conducted. From the results it was possible to deduct that the students performed well in areas of spatial thinking that deals with geographical features like points, lines and polygons, but not so well when faced with tasks concerning several spatial facts, overlay, and mentally visualizing 3-D images from 2-D information. Males generally scored higher than females in the test, especially if only answers that the students felt confident of were counted. Students from the Natural Science Programme outperformed the students from the Social Science Programme, even though the former didn’t have any formal education in geography from the upper secondary school. The thesis argues that a larger focus on spatial thinking in the geography subject could benefit the development of both a stronger stance for the subject in the education system, and the abilities and knowledge tied to spatial thinking of the students, especially those that are lacking formal education in other subjects that train the spatial thinking, mostly mathematics and physics.

Whereas no prior contribution has focused on the case of a medium-sized city in a developing country, such as Mexico, to explore how urban structure and its expansion has affected the spatial distribution of employment, three distinct, but related papers were developed, which combine urban economics literature and spatial sciences techniques to fill this gap and provide new evidence. The first paper, entitled "Spatial Distribution of Employment in Hermosillo, 1999 and 2004" identifies where employment subcenters are. Testing the presence of spatial effects, it concludes that an incipient process of employment suburbanization has taken place; however, the city still exhibits a monocentric structure. As a complement, a second paper, "Employment Density in Hermosillo, 1999-2004: A Spatial Econometric Approach of Local Parameters" tests if the Central Business District (CBD), despite suburbanization, maintains the traditional attributes of attracting activities and influencing the organization of employment around it. The CBD is still attractive, but its influence varies across space and economic sector, conclusions that were masked by global estimations. Thirdly, a study was essential to uncover how important is the urban structure and the suburbanization of jobs in explaining the dispersion resulting of households and workplaces (commuting). The paper entitled "Commuting in a Developing City: The Case of Ciudad Obregon, Mexico" examines this issue. To take advantage of the commuting information available, the study area was switched. In general, the results are consistent with those suggested by urban economics; moreover, the inclusion of workplace characteristics was a novelty to model commuting behavior and proves that space matters. Additionally, new evidence was provided to the field of spatial science through the applications of techniques able to expose the spatial effects associated with the distribution of employment, more specifically, the Exploratory Spatial Data Analysis(ESDA), Geographically Weighted Regression (GWR) with spatial effects, as well as the generalized multilevel hierarchical linear model (GMHL) were used. The new findings produced for this dissertation provide a more comprehensive understanding of urban dynamics and could help to improve the planning process. It is hoped that this dissertation will contribute to that development as well as stimulate further research.

This thesis seeks to contribute to the growing literature on the theoretical issues surrounding the notions of space and place, by examining how they can be put to work in a historical study. This work is achieved through a reading of Foucault, who not only sketched a history of space, but also undertook a number of spatial histories. To understand this, and these histories, this thesis begins by reading Foucault's professed influence on history, Nietzsche, and goes on to highlight the key role that Heidegger plays in this understanding. Just as Heidegger is central to Foucault's work on history, it is suggested that the importance of space also stems from Heidegger, especially from his work in the 1930s which critically engages with Nietzsche and the Romantic poet Hölderlin. The importance of space, or more fundamentally place, becomes central to Heidegger's later work on modern technology, his rethinking of politics and the πόλις, and art. Reading Foucault's work on history draws out the nature of his spatial language. Not only is his work replete with spatial metaphors, but he also made analyses of actual spaces. This is most evident in Foucault's two large scale historical projects – the history of madness from the Renaissance to the beginnings of psychology in Histoire de la folie, and the study of modern discipline in the army, hospitals, schools and prisons found in The Birth of the Clinic, Discipline and Punish but also in numerous shorter pieces and lectures. His two major works are re-read as spatial histories, and the standard interpretations to an extent re-placed, in the light of the argument developed in the previous chapters. Foucault's historical approach is often described as a history of the present: given the emphasis on space, it is here rethought as mapping the present.

Body schema is indispensable for sensorimotor control and learning, but it remains unclear whether it is associated with cognitive functions. Data from patients with spatial neglect support this view; yet observations in healthy participants are inconsistent. Here I conducted two sets of experiments examining influences of trunk position: the first probed attention and spatial working memory using a change detection task and a two-back task; the second used different versions of the Posner paradigm to examine whether head-on-trunk position governs disengagement of attention. In none of the experiments did I observe that trunk turns altered performance in the left versus right visual field in an ipsiversive fashion as reported in neglect. Nevertheless, I found that trunk-right position improved performance at eccentric locations of the visual field. The data are inconsistent with previous findings of head-on-trunk effects in normal participants. Further studies are required to clarify these discrepancies.

Body schema is indispensable for sensorimotor control and learning, but it remains unclear whether it is associated with cognitive functions. Data from patients with spatial neglect support this view; yet observations in healthy participants are inconsistent. Here I conducted two sets of experiments examining influences of trunk position: the first probed attention and spatial working memory using a change detection task and a two-back task; the second used different versions of the Posner paradigm to examine whether head-on-trunk position governs disengagement of attention. In none of the experiments did I observe that trunk turns altered performance in the left versus right visual field in an ipsiversive fashion as reported in neglect. Nevertheless, I found that trunk-right position improved performance at eccentric locations of the visual field. The data are inconsistent with previous findings of head-on-trunk effects in normal participants. Further studies are required to clarify these discrepancies.