How do Changes in Land Use Patterns Affect Species Diversity? an Approach for Optimizing Landscape Configuration

Heterogeneity of agricultural landscapes is supposed to be of significant importance for species diversity in agroecosystems (Weibull et al. 2003). Thus it is necessary to account for structural aspects of landscapes in land management decision processes. Spatial optimization models of land use can serve as tools for decision support. These models can aim at various landscape functions like nutrient leaching and economical aspects (Seppelt and Voinov 2002), water quality (Randhir et al. 2000) or habitat suitability (Nevo and Garcia 1996). However neighbourhood effects stay unconsidered in these approaches. In this paper we present an optimization model concept that aims at maximizing habitat suitability of selected species by identifying optimum spatial configurations of agricultural land use patterns. Bird species with diverging habitat requirements were chosen as target species. Habitat suitability models for these species are used to set up the performance criterion. Landscape structure is quantified by landscape metrics (McGarigal et al. 2002) estimated within the species home range. Statistical significance of these metrics for species presence was proven by a logistic regression model (Fielding and Haworth 1995). The landscape is represented by a grid based data set. Based on a genetic algorithm the optimization task is to identify an optimum configuration of model units. These model units are defined by contiguous cells of identical land use. Within this concept we can study how optimum but possibly artificial landscapes vary in structure depending on the selected species for which habitat suitability is maximized.

Towards Adaptive Radiotherapy through Development of Treatment Response Prediction

Despite modern treatment advances, overall survival (OS) remains poor for many cancers such as liver and brain. Cancer is a fundamentally heterogeneous and adaptable disease and therefore personalized adaptive treatment strategies may be a key towards improving OS. Radiotherapy, a commonly used cancer treatment technique which employs ionizing radiation to kill tumours, holds promise for delivering adaptive treatment. However, effective adaptation requires the ability to assess and predict tumour treatment response. Therefore development of treatment response prediction tools represents a critical first step towards improving patient outcomes via treatment adaptation. The overall goal of this thesis is to develop treatment response prediction methods with a view towards guiding adaptive radiotherapy. First, we investigated the relationship between radiation dose and local tumour control among patients with primary and metastatic colorectal liver tumours. We established and compared their dose-response relationships and found that 84 Gy and 95 Gy of radiation could provide 90% probabilities of 6-month local control for the primary and metastatic groups respectively. Tumour control most often cannot be improved simply through escalating the dose to the entire tumour due to increased risk of side effects. However, it may be possible to safely increase the dose to tumour sub-volumes. Therefore, the second and third contributions of this thesis involve development of image-based treatment response prediction methods which are needed to identify tumour sub-volumes where additional radiation should be deposited to improve tumour control. Our second contribution involved augmenting a voxel-based method known as parametric response mapping (PRM) to account for image registration error (IRE). The augmented PRM helped to quantify and visualize IRE-related variability. In our third contribution, we further generalized PRM to permit collective analysis of multi-parametric image data. The proposed method was applied to multi-parametric imaging from a patient cohort with glioblastoma and was found to predict OS ≥ 18 months (median OS) with a sensitivity and specificity of 90% and 78% respectively. In summary, these contributions provided some of the response assessment groundwork needed to guide adaptive RT. Image-based dose response relationships via the augmented and multi-parametric response maps will facilitate personalization and guidance of adaptive radiotherapy

Inviting Mindful Silence into Pedagogy: Supporting Agency, Voice, and Critical Engagement Through Silence

Across pedagogical approaches, silence and speech are rarely recognized as equally important ways to demonstrate knowledge. Favoring speech in the classroom indicates a specific set of assumptions that shows what formal teaching and learning settings should look like. I will approach silence in this study as an opportunity to create space for silent voices and invisible notions of agency. Through an exhaustive literature search and interpretive review of how contemporary pedagogical approaches currently assess silence, I invite the concept of mindful silence into pedagogy as a way to better address the ways that silence - not just speech - can advance teaching and learning. To pursue the inclusion of mindful silence into contemporary approaches to pedagogy I am following the guidelines already provided by a theory of invitational rhetoric. Invitational rhetoric can help mindful silence provide pedagogues and students an alternative pathway to teaching and learning. By reconsidering silence more centrally in interactive pedagogy, a more critical and inclusive classroom—and thus more critically-minded and diverse individuals—can learn how to engage in life-long learning and democratic citizenship in more productive ways. Treating silence as an intentional choice or strategy of teaching and learning thus invites new dimensions of self-reflection, active listening, and deep understanding of other’s perspectives to be included as part of a successful educational process. Long term, it is my hope that embracing mindful silence in pedagogy can change the educational environment but also return our focus on how a healthy democracy functions as a productive balance of thoughtfully speaking and critically listening