6 resultados para seedling emergence

em Duke University


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Cryptococcus gattii causes life-threatening disease in otherwise healthy hosts and to a lesser extent in immunocompromised hosts. The highest incidence for this disease is on Vancouver Island, Canada, where an outbreak is expanding into neighboring regions including mainland British Columbia and the United States. This outbreak is caused predominantly by C. gattii molecular type VGII, specifically VGIIa/major. In addition, a novel genotype, VGIIc, has emerged in Oregon and is now a major source of illness in the region. Through molecular epidemiology and population analysis of MLST and VNTR markers, we show that the VGIIc group is clonal and hypothesize it arose recently. The VGIIa/IIc outbreak lineages are sexually fertile and studies support ongoing recombination in the global VGII population. This illustrates two hallmarks of emerging outbreaks: high clonality and the emergence of novel genotypes via recombination. In macrophage and murine infections, the novel VGIIc genotype and VGIIa/major isolates from the United States are highly virulent compared to similar non-outbreak VGIIa/major-related isolates. Combined MLST-VNTR analysis distinguishes clonal expansion of the VGIIa/major outbreak genotype from related but distinguishable less-virulent genotypes isolated from other geographic regions. Our evidence documents emerging hypervirulent genotypes in the United States that may expand further and provides insight into the possible molecular and geographic origins of the outbreak.

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Addressing global fisheries overexploitation requires better understanding of how small-scale fishing communities in developing countries limit access to fishing grounds. We analyze the performance of a system based on individual licenses and a common property-rights regime in their ability to generate incentives for self-governance and conservation of fishery resources. Using a qualitative before-after-control-impact approach, we compare two neighbouring fishing communities in the Gulf of California, Mexico. Both were initially governed by the same permit system, are situated in the same ecosystem, use similar harvesting technology, and have overharvested similar species. One community changed to a common property-right regime, enabling the emergence of access controls and avoiding overexploitation of benthic resources, while the other community, still relies on the permit system. We discuss the roles played by power, institutions, socio-historic, and biophysical factors to develop access controls. © 2012 The Author(s).

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The main research question of this thesis is how do grand strategies form. Grand strategy is defined as a state's coherent and consistent pattern of behavior over a long period of time in search of an overarching goal. The political science literature usually explains the formation of grand strategies by using a planning (or design) model. In this dissertation, I use primary sources, interviews with former government officials, and historical scholarship to show that the formation of grand strategy is better understood using a model of emergent learning imported from the business world. My two case studies examine the formation of American grand strategy during the Cold War and the post-Cold War eras. The dissertation concludes that in both these strategic eras the dominating grand strategies were formed primarily by emergent learning rather than flowing from advanced designs.

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The current era of American Christianity marks the transition from a Western, white-dominated U.S. Evangelicalism to an ethnically diverse demographic for evangelicalism. Despite this increasing diversity, U.S. Evangelicalism has demonstrated a stubborn inability to address the entrenched assumption of white supremacy. The 1970s witnessed the rise in prominence of Evangelicalism in the United States. At the same time, the era witnessed a burgeoning movement of African-American evangelicals, who often experienced marginalization from the larger movement. What factors prevented the integration between two seemingly theologically compatible movements? How do these factors impact the challenge of integration and reconciliation in the changing demographic reality of early twenty-first Evangelicalism?

The question is examined through the unpacking of the diseased theological imagination rooted in U.S. Evangelicalism. The theological categories of Creation, Anthropology, Christology, Soteriology, and Ecclesiology are discussed to determine specific deficiencies that lead to assumptions of white supremacy. The larger history of U.S. Evangelicalism and the larger story of the African-American church are explored to provide a context for the unique expression of African-American evangelicalism in the last third of the twentieth century. Through the use of primary sources — personal interviews, archival documents, writings by principals, and private collection documents — the specific history of African-American evangelicals in the 1960s and 1970s is described. The stories of the National Black Evangelical Association, Tom Skinner, John Perkins, and Circle Church provide historical snapshots that illuminate the relationship between the larger U.S. Evangelical movement and African-American evangelicals.

Various attempts at integration and shared leadership were made in the 1970s as African-American evangelicals engaged with white Evangelical institutions. However, the failure of these attempts point to the challenges to diversity for U.S. Evangelicalism and the failure of the Evangelical theological imagination. The diseased theological imagination of U.S. Evangelical Christianity prevented engagement with the needed challenge of African American evangelicalism, resulting in dysfunctional racial dynamics evident in twenty-first century Evangelical Christianity. The historical problem of situating African American evangelicals reveals the theological problem of white supremacy in U.S. Evangelicalism.