The specificity and robustness of long-distance connections in weighted, interareal connectomes

Brain areas' functional repertoires are shaped by their incoming and outgoing structural connections. In empirically measured networks, most connections are short, reflecting spatial and energetic constraints. Nonetheless, a small number of connections span long distances, consistent with the notion that the functionality of these connections must outweigh their cost. While the precise function of these long-distance connections is not known, the leading hypothesis is that they act to reduce the topological distance between brain areas and facilitate efficient interareal communication. However, this hypothesis implies a non-specificity of long-distance connections that we contend is unlikely. Instead, we propose that long-distance connections serve to diversify brain areas' inputs and outputs, thereby promoting complex dynamics. Through analysis of five interareal network datasets, we show that long-distance connections play only minor roles in reducing average interareal topological distance. In contrast, areas' long-distance and short-range neighbors exhibit marked differences in their connectivity profiles, suggesting that long-distance connections enhance dissimilarity between regional inputs and outputs. Next, we show that -- in isolation -- areas' long-distance connectivity profiles exhibit non-random levels of similarity, suggesting that the communication pathways formed by long connections exhibit redundancies that may serve to promote robustness. Finally, we use a linearization of Wilson-Cowan dynamics to simulate the covariance structure of neural activity and show that in the absence of long-distance connections, a common measure of functional diversity decreases. Collectively, our findings suggest that long-distance connections are necessary for supporting diverse and complex brain dynamics.Comment: 18 pages, 8 figure

Aging Out of the Foster Care System to Adulthood: Findings, Challenges, and Recommendations

To assess and ultimately help meet the needs of youth who age out of foster care in the United States, the Joint Center Health Policy Institute (JCHPI) -- with support from the Robert Wood Johnson Foundation and in partnership with the Black Administrators in Child Welfare Inc. (BACW) -- conducted reconnaissance on the unmet needs of these youth. This project was undertaken to guide the Robert Wood Johnson Foundation in thinking about steps they might take to help meet the needs of youth who age out of foster care in this country. Conducting a literature review, a telephone survey, and listening sessions enabled us to develop insights into the workings of the foster care system and the experiences of youth while in the system and when aging out of it

Make the Inaugural Great Again: A Rhetorical Analysis of Donald J. Trump’s Inaugural Address

In this thesis, I utilized three distinct theories (ideographs, dramatism, and the bully pulpit) to rhetorically analyze and assess President Trump’s 2017 inaugural address. Ultimately, I analyzed whether Trump deviated from Campbell and Jamieson’s (1985) presidential inaugural expectations. While the presidential inaugural address was the only text analyzed, implications were drawn from Trump’s rhetoric leading up to and within the inaugural. This thesis also analyzed Trump’s rhetoric through social media, specifically Twitter, and looked at the context surrounding the inaugural. I suggest, through my research, that Trump does deviate from the traditional framework of the inaugural address, and ultimately modernized the inaugural through his language. The analysis provided insight into who Donald J. Trump is as a rhetor and the modern use of each theoretical lens

In pursuit of conjugation in one-dimension: Synthetic studies of oligomeric and polymeric organic materials

Chapter 1. Ring-Opening Alkyne Metathesis Polymerization of Dibenzocyclooctynes A molybdenum(VI) propylidyne substituted with bidentate phenoxides will react with dibenzocyclooctynes in living ring-opening alkyne metathesis polymerization (ROAMP). The corresponding monodentate phenoxides do not yield well-controlled polymerizations. However, if the substrate in the ROAMP reaction is an aliphatic cyclooctyne, uncontrolled, non-living polymerizations take place in all cases. Chapter 2. Ring-Opening Alkyne Metathesis via a Tungstenatetrahedrane Intermediate A cyclopropenone-modified dibenzocyclooctyne will undergo a single ring opening alkyne metathesis reaction in the presence of Schrock's tris(tert-butoxy)tungsten(VI) neopentylidyne--a highly active alkyne metathesis catalyst. Despite the enormous amount of ring strain present in and related diphenycyclooctadiynes, these compounds do not readily undergo ring-opening alkyne metathesis polymerization (ROAMP), even with the most active alkyne metathesis catalysts available. The ring-opening of 1 proceeds via a tungstenatetrahedrane intermediate. Because of its sluggish reactivity, we were able to follow the ring-opening reaction by NMR to gain mechanistic insight into this remarkable behavior. Chapter 3. Functionaliztion of Diphenyloligoenes Bromine and carboxylic acid substituted α,ω-diphenyl-µ,ν-dicyano-oligoenes (DPDCn) were synthesized up to 9 and 7 olefin units in length, respectively. The carboxylic acid functionalized oligoenes (DPDCn-CO2H) are aligned through hydrogen bonding to DMF in the solid state. These can also be used to direct monolayer formation of Fe3O4 on single crystalline, 100 Gallium Arsenide

REAL-TIME 4D ULTRASOUND RECONSTRUCTION FOR IMAGE-GUIDED INTRACARDIAC INTERVENTIONS

Image-guided therapy addresses the lack of direct vision associated with minimally- invasive interventions performed on the beating heart, but requires effective intraoperative imaging. Gated 4D ultrasound reconstruction using a tracked 2D probe generates a time-series of 3D images representing the beating heart over the cardiac cycle. These images have a relatively high spatial resolution and wide field of view, and ultrasound is easily integrated into the intraoperative environment. This thesis presents a real-time 4D ultrasound reconstruction system incorporated within an augmented reality environment for surgical guidance, whose incremental visualization reduces common acquisition errors. The resulting 4D ultrasound datasets are intended for visualization or registration to preoperative images. A human factors experiment demonstrates the advantages of real-time ultrasound reconstruction, and accuracy assessments performed both with a dynamic phantom and intraoperatively reveal RMS localization errors of 2.5-2.7 mm, and 0.8 mm, respectively. Finally, clinical applicability is demonstrated by both porcine and patient imaging