This thesis examines the suburban verge’s latent potential as an alternative public space. It is located between the boundaries of private properties and public streets, where territorial boundaries and ownership are unclear. The site for this thesis is the southeast quadrant of the intersection at Jane Street and Finch Avenue West in the former city of North York, now part of Toronto. The intersection reveals a fertile field of public activity that engenders new forms of social engagement and invites a reconsideration of public space in the urban periphery. A product of Modern planning, the suburban verge is a buffer between vehicles and pedestrians. Home to hydro poles, streetlights, small-scale furnishings and the ubiquitous cast-in-place concrete sidewalk, the suburban verge is a definitive element of the suburban landscape that accounts for a substantial amount of neglected public land. The suburban verge’s ambiguity attracts a variety of unsanctioned and informal activities. At Jane and Finch, socio-economic issues, a diverse population and escalating pressure to increase density further intensify this unscripted behaviour. This thesis calls attention to the unrealized potential of the suburban verge. It does not set out to create new public space; rather, it draws upon existing social patterns in order to enrich the suburban public realm. Subtle inflections in the existing terrain, deliberately modest in form and operation, expand the social and ecological capacity of the suburban verge and demonstrate the need to consider the potential of everyday practices as a vehicle for generating dynamic public space.

In rapidly growing North American cities, large-scale urban developments struggle to create a distinctive sense of community. Responding to increasing trends of isolation, decentralization, cultural and artistic expressions, capitalizing on local knowledge and people, have emerged as driving forces in the creation of authentic community development. Working within the existing model of large-scale development, interrogating process and program in relation to community building, this thesis asserts that architecture and urban design must calibrate themselves in response to the emerging trends by taking a multidisciplinary and comprehensive approach to design. This thesis asks the following questions: What is architecture’s contribution to a creative community? How can our existing instant communities continue to evolve in response to changing needs? Where can we find public space in our contemporary communities? Can public art be used as a tool for community building? The case study site, surrounding the Jane-Finch intersection, was rapidly developed from 1960 to 1970. The imposing Palisades apartment complex, standing on the north-east corner of the intersection, has become an icon in the neighbourhood. Three distinctly modern buildings rise out of a grassy lawn to be seen throughout the larger neighbourhood. The development represents both challenges and opportunities; 4,400 people know it as home while others associate it with media reports of poverty, crime and an aging legacy of modern architecture (San Romanoway Revitalization Association 2009). Issues of identity, public space, scale and implementation are examined through case studies of highly designed architectural precedents and informal grassroots organizations to inform the design proposal. Through the re-conception of the ambiguous ground plane at the base of the Palisades apartment complex as an educational and cultural campus for the emerging arts community, this thesis demonstrates the potential role of architecture in supporting creative community building and an expanded understanding of the contradictory role of an architect as mediator, dreamer and realist.

The evolution of adaptation depends on genetic and phenotypic variation, both of which are expected to be depleted in populations as a result of selection. Thus, understanding the maintenance of variation in fitness-related traits is of central importance in evolutionary biology as such processes can mitigate the constraining effects of adaptation on evolutionary change. Secondary sexual traits involved in attracting mates offer conspicuous examples of adaptation and are suggestive of strong directional selection, yet abundant variation is commonly observed both within and among populations. One explanation posits that variation in elaborate sexual traits might be maintained by fluctuating selection, such that episodes of intense selection are interspersed by periods in which variation is shielded from elimination, yet little is known about the processes that lead to such heterogeneity. In many cases, mate choice results from highly localized social interactions such that fine scale demographic variation may contribute to variation in patterns of sexual selection, especially when individuals' attractiveness is assessed in comparison to local conspecifics. Additionally, selection on sexual traits might fluctuate when the fitness consequences of mate choice depends on the complementarity of male and female characters, such as when offspring viability is influenced by the genetic relatedness of parents. In this dissertation, I examined demographic, behavioral, and genetic causes of variation in sexually-selected male plumage ornaments in a wild population of house finches (Carpodacus mexicanus). Over a five-year field study, I found that mate choice occurred largely within small social groups, the composition of which was influenced by active social sampling by males, suggesting that variation in male sexual traits may be maintained as a result of behaviors that enable individuals to shape their environment of selection. Additionally, using a panel of neutral molecular markers, I found that parental relatedness predicted multiple metrics of offspring fitness, and also affected the ability of neonates to buffer development from environmental variation, suggesting that inbreeding is likely to have pervasive effects on the evolution of adaptation. Taken together, these studies provide evidence of distinct processes that contribute to the maintenance of quantitative variation in sexual traits in this natural population.

The Australian Zebra Finch (Taeniopygia guttata) is an important animal model for vertebrate development and behavior. New research initiatives in the fields of epigenetics rely heavily on injecting hormones and environmental toxins directly into the eggs of different bird species such as zebra finches and other passerine songbirds to replicate the effects maternal condition on offspring. However, the widely used method of egg-injections does not accurately replicate physiological conditions, as the injected substances remain concentrated at the injection site for extended periods and do not diffuse into the developing tissues. Therefore, we propose an alternative method to injection protocols that takes advantage of the porous nature of eggs. Corticosterone (CORT), a major vertebrate stress hormone, dissolved in ethyl alcohol was applied to the surface of zebra finch eggs daily. The effect of this treatment on decreasing hatching success shows that topical hormonal treatments are a viable alternative to egg injection.

Thesis (Ph.D.)--York University, 2006. Graduate Programme in Environmental Studies. / Typescript. Includes bibliographical references (leaves 311-327). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:NR29539

Dissertation (Ph.D.)--Auburn University, 2006. / Abstract. Includes bibliographic references (p.74-92).

Sequences of stereotyped actions are central to the everyday lives of humans and animals, from the kingfisher's dive to the performance of a piano concerto. Lashley asked how neural circuits managed this feat nearly 6 decades ago, and to this day it remains a fundamental question in neuroscience. Toward answering this question, vocal performance in the songbird was used as a model to study the performance of learned, stereotyped motor sequences. The first component of this work considers the song motor cortical zone HVC in the zebra finch, an area that sends precise timing signals to both the descending motor pathway, responsible for stereotyped vocal performance in the adult, and the basal ganglia, which is responsible for both motor variability and song learning. Despite intense interest in HVC, previous research has exclusively focused on describing the activity of small numbers of neurons recorded serially as the bird sings. To better understand HVC network dynamics, both single units and local field potentials were sampled across multiple electrodes simultaneously in awake behaving zebra finches. The local field potential and spiking data reveal a stereotyped spatio-temporal pattern of inhibition operating on a 30 ms time-scale that coordinates the neural sequences in principal cells underlying song. The second component addresses the resilience of the song circuit through cutting the motor cortical zone HVC in half along one axis. Despite this large-scale perturbation, the finch quickly recovers and sings a near-perfect song within a single day. These first two studies suggest that HVC is functionally organized to robustly generate neural dynamics that enable vocal performance. The final component concerns a statistical study of the complex, flexible songs of the domesticated canary. This study revealed that canary song is characterized by specific long-range correlations up to 7 seconds long-a time-scale more typical of human music than animal vocalizations. Thus, the neural sequences underlying birdsong must be capable of generating more structure and complexity than previously thought.

<p>The development of the avian embryo is dependent of heat provisioning from the parents. To increase the heat transfer to a cooled egg the Zebra finch females develop a brood patch. Mild cooling generally constricts the blood vessels but the Arterio-venous anastomoses (AVA) in the brood patch in birds dilate. This is called cold-induced vasodilation CIVD. The Zebra finches were anesthetized with isoflurane and the brood patch was stimulated with a cooling probe set at 20-21 °C. Differences in the vascular changes to cooling in broody and non- broody birds were studied by comparing males and broody females. The brood patch skin was cooled, but no cold-induced vasodilation (CIVD) was documented for the males or the broody females. Isoflurane anesthesia depresses the sympathetic nervous system activity and the results support that the mechanism for CIVD in the brood patch of Zebra finches depends on a neural pathway, but does not exclude a local non-neural mechanism.</p>

<p>During the breeding season Zebra finch, Taeniopygia guttata, females develops a brood patch on the ventral surface which facilitates heat exchange between the incubating bird and the egg. The brood patch has to be sensitive to changes in temperature, so that the eggs can be kept at an optimal temperature for embryo development. If the egg temperature drops it has to be re-warmed. Mild cooling of the brood patch has been shown to cause cold induced vasodilation, but the responsible mechanism for this is not known. In this study we investigated if known thermoreceptors, TRPV3 and TRPV4, could be involved in the alteration of blood flow. To activate TRPV3 and TRPV4 two agonists, carvacrol and 4α-PDD respectively, were applied on the brood patch. Changes in skin temperature and vascularity were then examined. The results obtained did not reveal any changes in the vascularity. Temperature changes in the skin that could be caused by an alteration in blood flow did not significantly change either. Still, a role of these channels in the brood patch cannot be excluded.</p>

During the breeding season Zebra finch, Taeniopygia guttata, females develops a brood patch on the ventral surface which facilitates heat exchange between the incubating bird and the egg. The brood patch has to be sensitive to changes in temperature, so that the eggs can be kept at an optimal temperature for embryo development. If the egg temperature drops it has to be re-warmed. Mild cooling of the brood patch has been shown to cause cold induced vasodilation, but the responsible mechanism for this is not known. In this study we investigated if known thermoreceptors, TRPV3 and TRPV4, could be involved in the alteration of blood flow. To activate TRPV3 and TRPV4 two agonists, carvacrol and 4α-PDD respectively, were applied on the brood patch. Changes in skin temperature and vascularity were then examined. The results obtained did not reveal any changes in the vascularity. Temperature changes in the skin that could be caused by an alteration in blood flow did not significantly change either. Still, a role of these channels in the brood patch cannot be excluded.