A comparative study of life history and gene flow in darters (Pisces: Percidae)

Gene flow, or the exchange of genes between populations, is important because it determines the evolutionary trajectory of a species, including the relative influences of genetic drift and natural selection in the process of population differentiation. Gene flow differs among species because of variation in dispersal capability and abundances across taxa, and historical forces related to geological or lineage history. Both history and ecology influence gene flow in potentially complicated ways, and accounting for their effects remains an important problem in evolutionary biology. This research is a comparative study of gene flow and life-history in a monophyletic group of stream fishes, the darters. As a first step in disentangling historical and ecological effects, I reconstructed the phylogenetic relationships of the study species from nucleotide sequences in the mtDNA control region. I then used this phylogeny and regional glaciation history to infer historical effects on life-history evolution and gene flow in 15 species of darters. Gene flow was estimated indirectly, using information from 20 resolvable and polymorphic allozyme loci. When I accounted for historical effects, comparisons across taxa revealed that gene flow rates were closely associated with differences in clutch sizes and reproductive investment patterns. I hypothesized that differences in larval dispersal among taxa explained this relationship. Results from a field study of larval drift were consistent with this hypothesis. Finally, I asked whether there was an interaction between species' ecology and genetic differentiation across biogeographically distinct regions. Information from allozymes and mtDNA sequences revealed that life history plays an important role in the magnitude of species divergence across biogeographic boundaries. These results suggested an important association between life histories and rates of speciation following an allopatric isolation event. This research, along with other studies from the literature, further illustrates the enormous potential of North American freshwater fishes as a system for studying speciation processes. ^

Armenia's foreign policy, 1991���2004: Between history and geopolitics

This dissertation is the first systematic study of Armenia���s foreign policy during the post-independence period, between 1991 and 2004. It argues that a small state���s foreign policy is best understood when looking at the regional level. Armenia���s geographic proximity to Iran, Russia and Turkey, places it in an area of heightened geopolitical interest by various great powers. This dissertation explores four sets of relationships with Armenia���s major historical ���partners���: Russia, Iran, Turkey and the West (Europe and the United States). Each relationship reveals a complex reality of a continuous negotiation between ideas of history, collective memory, nationalism and geopolitics. A detailed study of Armenia���s relations with these powers demonstrates how actors��� relations of amity and enmity are formed to constitute a regional security complex. Turkey represents the ultimate ���other���, while both Europe and Iran are seen as ideational ���others���, whose role in Armenia���s foreign policy, aside from pragmatic policy considerations, reflects a normative quest. Russia and the United States, on the other hand, represent the powerful structural forces that define the regional security complex, in which Armenia operates. This dissertation argues that although Armenia has been severely constrained in certain foreign policy choices, it was adept at carving a space for action that privileged the issue of Nagorno-Karabakh over other geopolitical imperatives.

History and evolutionary trajectory of the Iranian nuclear program

What actors and processes at what levels of analysis and through what mechanisms have pushed Iran's nuclear program (INP) towards being designated as a proliferation threat (securitization)? What actors and processes at what levels of analysis and through what mechanisms have pushed Iran's nuclear program away from being designated as an existential threat (de-securitization)? What has been the overall balance of power and interaction dynamics of these opposing forces over the last half-century and what is their most likely future trajectory? ^ Iran's nuclear story can be told as the unfolding of constant interaction between state and non-state forces of "nuclear securitization" and "nuclear de-securitization." Tracking the crisscrossing interaction between these different securitizing and de-securitizing actors in a historical context constitutes the central task of this project. ^ A careful tracing of "security events" on different analytical levels reveals the broad contours of the evolutionary trajectory of INP and its possible future path(s). Out of this theoretically conscious historical narrative, one can make informed observations about the overall thrust of INP along the securitization - de-securitization continuum. ^ The main contributions of this work are three fold: First, it brings a fresh theoretical perspective on Iran's proliferation behavior by utilizing the "securitization" theory tracing the initial indications of the threat designation of INP all the way back to the mid 1970s. Second, it gives a solid and thematically grounded historical texture to INP by providing an intimate engagement with the persons, processes, and events of Tehran's nuclear pursuit over half a century. Third, it demonstrates how INP has interacted with and even at times transformed the NPT as the keystone of the non-proliferation regime, and how it has affected and injected urgency to the international discourse on nuclear proliferation specifically in the Middle East.^

African History and Identity: A Case Study of Black British Students in London

Through the administration of questionnaires and interviews in six of London���s secondary schools, this case study seeks to investigate Black Britons��� self-concepts and attitudes toward curricular depictions of continental and diasporan Africans and the extent to which the African Union���s (A.U.) Pan-African outreach agenda may be advanced or challenged.

Review of the History and Current Status of Cell-Transplant Approaches for the Management of Neuropathic Pain

Treatment of sensory neuropathies, whether inherited or caused by trauma, the progress of diabetes, or other disease states, are among the most difficult problems in modern clinical practice. Cell therapy to release antinociceptive agents near the injured spinal cord would be the logical next step in the development of treatment modalities. But few clinical trials, especially for chronic pain, have tested the transplant of cells or a cell line to treat human disease. The history of the research and development of useful cell-transplant-based approaches offers an understanding of the advantages and problems associated with these technologies, but as an adjuvant or replacement for current pharmacological treatments, cell therapy is a likely near future clinical tool for improved health care.

Armenia's Foreign Policy, 1991-2004: Between History and Geopolitics

This dissertation is the first systematic study of Armenia���s foreign policy during the post-independence period, between 1991 and 2004. It argues that a small state���s foreign policy is best understood when looking at the regional level. Armenia���s geographic proximity to Iran, Russia and Turkey, places it in an area of heightened geopolitical interest by various great powers. This dissertation explores four sets of relationships with Armenia���s major historical ���partners���: Russia, Iran, Turkey and the West (Europe and the United States). Each relationship reveals a complex reality of a continuous negotiation between ideas of history, collective memory, nationalism and geopolitics. A detailed study of Armenia���s relations with these powers demonstrates how actors��� relations of amity and enmity are formed to constitute a regional security complex. Turkey represents the ultimate ���other���, while both Europe and Iran are seen as ideational ���others���, whose role in Armenia���s foreign policy, aside from pragmatic policy considerations, reflects a normative quest. Russia and the United States, on the other hand, represent the powerful structural forces that define the regional security complex, in which Armenia operates. This dissertation argues that although Armenia has been severely constrained in certain foreign policy choices, it was adept at carving a space for action that privileged the issue of Nagorno-Karabakh over other geopolitical imperatives.