Doctor of Philosophy, Miami University, 2014, Zoology

Prey species sit at a pivotal point in food webs, serving as a connection between predators and energy sources (e.g., plants or detritus). Most prey face multiple predators and must integrate information about predation risk if they are to avoid being consumed. Meanwhile, predators interact with one another and can increase or decrease their combined pressure on prey. By interacting with their prey, predators can indirectly affect ecosystem functions, even without reducing prey population size. The goal of my dissertation was to understand how prey survive in a world with multiple predators and to uncover linkages between predators and the soil food web. I first tested hypotheses about how the wolf spider Pardosa milvina responds to cues from multiple predators (the larger wolf spider Tigrosa helluo and the ground beetle Scarites quadriceps) and how inaccurate information regarding predation threat affects survival. Pardosa were capable of distinguishing between predators and responding adaptively, though prey responses were not optimized when predators were at elevated hunger levels. As a second step, I allowed multiple predators (the wolf spider Rabidosa rabida along with Tigrosa and Scarites) to freely interact with each other and their prey (Pardosa) to test the influence of predator characteristics and the occurrence of intraguild predation on prey survival. Overall, I found support for a predictive framework of emergent multiple predator effects, though intraguild predation events caused significant deviations from model predictions. I also investigated the consumptive and nonconsumptive effects predators can have on their environment, focusing on the detrital food chain. The presence of either Pardosa or their cues impacted CO2 flux and soil nitrogen content as mediated by the detritivore Sinella curviseta, suggesting indirect top-down control of ecosystem function by predators. Finally, I tested the response of Sinella to cues indicating predation risk to de (open full item for complete abstract)

Committee: Ann Rypstra Ph.D. (Advisor); Nancy Solomon Ph.D. (Committee Member); Brian Keane Ph.D. (Committee Member); Tom Crist Ph.D. (Committee Member); Dave Gorchov Ph.D. (Committee Member) Subjects: Biology; Ecology; Entomology; Organismal Biology; Soil Sciences; Zoology

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, Case Western Reserve University, 2013, Physics

The optical properties of one-dimensional layered materials provides a wealth of interesting phenomena. Fine control of the optical properties of the constituent materials and the thicknesses of each layer allows for sophisticated design of useful optical devices. Optical devices based on one-dimensional layered structures may have significant contributions in solving some of society's greatest problems in the coming century. The first of these challenges is to transition from fossil fuel energy generation to low-carbon, renewable energy replacements. Among the many proposed solutions is solar photovoltaic energy capture. In solar photovoltaics, light is converted to electric current by generating charge carriers in semiconductors. These charge carriers are then moved to opposing electrodes generating an electric current. These components: semiconductor, electrodes, and a supporting substrate form a layered optical system that can be studied. The interaction between absorbing material and the weak optical cavity formed by these electrodes causes enhanced absorption. By carefully designing the layer thicknesses, the absorption in the semiconductor layer can be tuned. In addition, the total absorbed solar photons vary as functions of the layer thicknesses requiring optimization by calculation and experiment. The second challenge is to store digital data for several decades at low-cost and with minimal use of power-consuming magnetic hard drive disks. Using scalable polymer processing techniques, it is possible to fabricate a multilayer optical data storage medium that satisfies the need for low-cost, scalable storage capacity. With a large number of physical layers, only small changes are needed to optical read/write hardware avoiding the pitfalls encountered with holographic and other exotic optical data storage technologies. The design and optimization of solar photovoltaic and optical data storage devices is considered. In addition, characterization of (open full item for complete abstract)

Committee: Kenneth Singer (Advisor); Rigoberto Advincula (Committee Member); Rolfe Petschek (Committee Member); Jie Shan (Committee Member) Subjects: Optics; Physics