Browsing by Subject "connectivity"

Now showing 1 - 3 of 3
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    Does substance use during youth cause lasting changes in resting-state neurophysiology and brain functional connectivity? A co-twin control investigation
    (2017-08) Burwell, Scott
    This dissertation comprises two studies aimed at disentangling potential causal effects of recreational substance use (alcohol, cannabis, tobacco) on resting-state electroencephalogram (EEG) and functional magnetic resonance imaging (fMRI) brain outcomes in a community sample of young adults. As noted by the introductory text for each study, there is a dearth of causally-informative research designs in published literature regarding whether drug and alcohol use has lasting effects on human EEG and fMRI. These two studies intend to bridge this gap by utilizing a causally-informative co-twin control (CTC) research design which utilizes the fact that twins reared in the same home are matched on many factors (e.g., genes, parental substance use, SES) that contribute to confounding in the hypothetical causal link between substance use and brain outcomes in extant cross-sectional research. As such, within twin-pair differences in use can be exploited to study within twin-pair differences in brain outcome (e.g., EEG, fMRI) to understand possible causal effects.
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    Reconnecting Communities to the River: Exploring Barriers to Benefits of a Restored Waterfront in a Post-Industrial Community
    (2023-05) Green, Sophia
    As a result of historic industry on the western Duluth waterfront, state, federal, and tribal partners worked to restore 240 acres of coastal wetland habitat in the bays of the St. Louis River estuary known as Kingsbury Bay and Grassy Point. The goals of the restoration projects were to restore coastal wetland quality and to improve user amenities such as trails, fishing piers, and bird-watching platforms. The restoration projects were completed in October 2021. During the same period, significant progress was made to complete a new river heritage trail known as the Waabizheshikana along the restoration area. Despite awareness that the restored wetlands can provide a variety of ecosystem services to local neighborhoods, which are socially vulnerable and have poor access to the waterfront, very little is known about neighborhood access to and community use of the restored green and blue spaces. This research study aims to understand community access to and use of the restoration areas through exploring the underlying barriers of use and access that are associated with safety, stigma, and connectivity. Historical policies were reviewed to curate a timeline of influential events that impacted community sense of place and cohesion. Additionally, survey instruments were utilized at specific sites to study community access, connectivity, and social barriers such as stigma and safety, to sites. This study found that historic decision-making in urban design and transportation planning of communities in the West Duluth region perpetuated inequalities in neighborhood green space quantity. Additionally, this study inferred differences in green space use by local and non-local communities. The outcomes from this study provided recommendations to support decision making in the field of urban planning, environmental justice, and restoration planning in postindustrial urban communities. More specifically the results will be shared with the interested stakeholders including the City of Duluth and Minnesota Department of Natural Resources. Other relevant audiences may include the Great Lakes National Program Office, whom are responsible for cleaning up Area of Concerns. Recommendations informed by this research intend to best support neighborhood connectivity to green and blue space so that restoration benefits such as ecosystem services may be actualized by existing underprivileged communities to promote community health and wellbeing.
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    Reliability Analysis of Partitioned Optical Passive Stars Networks
    (1997) Cao, Feng
    We study reliability in the all-optical Partitioned Passive Stars (POPS) topology. POPS is a physical architecture to scale the t raditional optical passive star couplers and explore the advantages of high noise immunity and single-hop. The reliability and fault tolerance in POPS rely on its connectivity. In this study, we analyze the worst case for network partitions due to either node failures or link errors. For node connectivity, we show that the whole system remains connectivity no matter how many nodes don't work. For link connectivity, we analyzed some worst cases due to link errors and the lower bound for connectivity is demonstrated. Some sufficient approaches are proposed to detect and keep connectivity of the whole system.