Doctor of Philosophy, The Ohio State University, 2019, Communication

The aim of the present study was to examine neural correlates and mechanisms underlying the psychological mechanisms formalized in a computational model of quantum cognition, the belief-action-entanglement (BAE) model. An analysis of frequency band activity in the brain was carried out to test these mechanisms. The BAE model proposes that communication acts as a measurement that interferes with the evaluative processes prior to a decision (Busemeyer, Wang, & Lambert-Mogiliansky, 2009; Pothos & Busemeyer, 2009; Z. Wang & Busemeyer, 2016). Two key mechanisms were conceptualized and formalized in the BAE model: (1) the superposition state which arises from uncertainty and dissonance when deciding between two or more actions, and (2) the transition from a superposition state to a determinate one during the action evaluation process. These mechanisms correspond with the psychological function and timing of two frequency bands. The frontal-midline (FM) theta (3-8 Hz) indexes conflict processing, a state analogous to cognitive dissonance. Parietal alpha power indexes search and integration processes in memory which captures evolution from the superposition state to a determinate one. To test the extent communication influenced these underlying mechanisms, we employed a category-decision paradigm used in behavioral studies of the BAE model. The study manipulated communication in three ways: receiving information, self-expressing, and no communication. EEG data was collected from 32 participants. The subsequent analysis of FM theta and parietal alpha-beta frequency band activity provided modest support for the effect of communication on the proposed BAE model mechanisms. Specifically, FM theta activity offered initial evidence that communication resolves dissonance or uncertainty in the superposition state. Further, parietal alpha-beta suppression provided support for the proposition that communication modulates the evolution of the cognitive system until a decision (open full item for complete abstract)

Committee: Joyce Wang PHD (Advisor); Jason Coronel PHD (Committee Member); Richard Huskey PHD (Committee Member) Subjects: Cognitive Psychology; Communication; Neurosciences

Doctor of Philosophy, Miami University, 2018, Political Science

Adding to the existing literature examining the challenges of democratization in African states, this work addresses how elite settlements have resulted in the gradual development of the authoritarian state in Zimbabwe. Drawing from similar arguments by Bratton and van de Walle (1997) and Bratton (2014) that contend that settler oligarchies such as Zimbabwe simply inherited and continued the raw power politics of the violent colonial state, I explore the contingency of elite settlements and their impact on stalling democratic movements. Following the argument by Higley and Burton (1989) that elite settlements offer the possibility of democratic outcomes, given that they contribute to political stability through boundary setting and horizontal accountability, in this dissertation I contend that elite settlements only accelerated the rise of ZANU-PF as the dominant political party. Instead of facilitating political openings conducive to democracy, the inability of elite settlements to guarantee an equal distribution of power among competing groups reinforced authoritarian rule and political violence. As an exploratory dissertation aimed at explaining the authoritarian state in Zimbabwe rather than focusing on theory-testing or building a set of hypotheses, my research focuses on elite settlements as a possible framework for future comparative studies that examine the main features of political transition in Africa.

Committee: Abdoulaye Saine (Committee Chair); Richard Quantz (Committee Member); Venelin Ganev (Committee Member); Walt Vanderbush (Committee Member) Subjects: African Studies; Comparative; Political Science

Doctor of Philosophy, The Ohio State University, 2016, Chemistry

Research in this dissertation studies the charge dynamics in the MLCT excited states of trans-M2L2L'2 and M2L4 paddlewheel compounds (M = Mo or W) which represent typical TM compounds and have strong light absorption in the UV-visible range. A series of trans-M2L2L'2 and M2L4 compounds are prepared where L is a MLCT-active amidinate, amide or thioamide ligand (L = NN, NO or NS corresponding to (NPh)(X)CC=CPh where X = NPh, O, S, respectively) and L' is an auxiliary carboxylate ligand which does not allow low energy MLCT transitions. Substitution of the MLCT and auxiliary ligands creates controlled variation in both regio-symmetry and electronic structures of these compounds. The compounds are studied using X-ray single crystallography, steady-state absorption, emission and time-resolved spectroscopy techniques. The charge distribution and charge dynamics in the excited states of these molecules are followed by IR reporters like the ethynyl groups using femtosecond time-resolved infrared spectroscopy (fs-TRIR). The different charge distribution patterns observed in the MLCT states are attributed to tunable inter-ligand electron transfer between acceptor ligands across the L-Msub>2-L chain on the vibrational time-scale (~10-12 s).

Committee: Claudia Turro (Advisor); Malcolm Chisholm (Advisor); Hannah Shafaat (Committee Member); Patrick Woodward (Committee Member); Hamish Fraser (Committee Member) Subjects: Chemistry

Doctor of Philosophy (PhD), Ohio University, 2006, Physics (Arts and Sciences)

The 12C(alpha,gamma) 16O radiative capture reaction is one of the most important reactions in nuclear astrophysics as its reaction rate determines the C/O ratio in the Universe. A better understanding of this reaction is what motivates the experiments presented in this thesis. In experiments performed at Ohio University angular distributions and branching ratios of the 7.12- and 6.92-MeV transitions in 16O were measured. An upper limit was set on the 7.12 to 6.13-MeV transition in 16O. These results will better constrain the alpha-reduced width of the 6.92-MeV state in 16O which is important for the extrapolation to helium-burning energies of both the E2 transition and cascade through the 6.92-MeV state. At the DRAGON recoil separator at TRIUMF, Canada, the E to 6.05 MeV transition in 12C(alpha,gamma) 16O was measured over a wide range of energies. The result shows that the cascade through the 6.05-MeV state is the most important cascade in 12C(alpha,gamma) 16O with an extrapolated S-factor at 300 keV, S 6.05(300)=25±16 keV b. A new value for the total S-factor at 300 keV is proposed.

Committee: Carl Brune (Advisor) Subjects: Physics, Nuclear