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We tested the prediction that resting frontal brain asymmetry would be a marker of vulnerability for depression among adolescents. Baseline electroencephalographic (EEG) activity was recorded from 12-14 year-old adolescent children whose mothers had a history of depression (high-risk group) and whose mothers were lifetime-free of Axis I psychopathology (low-risk group). Across all three reference montages derived, high-risk adolescents demonstrated the hypothesized pattern of relative left frontal hypoactivation on alpha band measures. Unexpectedly, we found that socioeconomic status (SES) also predicted alpha asymmetry. When the effects of SES and risk status were jointly assessed, only SES contributed unique variance to the prediction of frontal brain asymmetry. Significant effects were also observed in other bands but all effects w...
The objective of this research was to design and develop a system capable of displaying cortical brain function during image-guided neurosurgery. Brain function was determined using a cortical stimulator, classified according to function type, and displayed along with pre-operative tomographic and rendered images of the brain. In addition to displaying brain function acquired from the patient undergoing surgery, a probabilistic map of functional information acquired from a database or previous patients may also be displayed. This information is stored in an atlas coordinate system and can be mapped to the patient's coordinate system for display during surgery. The entire system was tested and evaluated during three human neurosurgery procedures. Functional information corresponding to speech, motor, and sensory regions was identified a...
This dissertation explores African and Portuguese roles in the rise of the Spanish Caribbean's most important port cities, with particular emphasis on Cartagena de Indias and Havana. During the late sixteenth and early seventeenth centuries, Portuguese and Luso-African mariners, merchants, and immigrants linked the Spanish Caribbean to a broader Portuguese maritime world. This network's most significant outcome was the forced migration of tens of thousands of African captives, funneled to the Caribbean in overlapping waves from Upper Guinea, Lower Guinea, and West Central Africa. Spain's heavy reliance on sub-Saharan Africans and their descendants to populate and sustain key Caribbean seaports resulted in social transformations which often mirrored or directly responded to contemporary events in precolonial Western Africa. Rather than ...
The current study used the semantic differential as a guiding tool to investigate the transfer pattern between judgment tasks. Subjects judged the meaning of words on semantic scales such as pleasant/unpleasant and strong/weak. In accordance with TAP, transfer was task specific. Maximum transfer was found when the test task scale was the same as the acquisition task scale. When the task scales represented orthogonal semantic dimensions, no significant transfer was found. When the task scales differed but involved common semantic dimensions, transfer pattern could be either relatively symmetrical or not. With an instance approach, modeling of experimental data suggested that two important variables underlying the transfer pattern were distance/dissimilarity between scales and spread/variability of the scales. Transfer was inversely rela...
A new inter-modality surface registration algorithm that uses textured point clouds and mutual information is presented within the context of model-updated image guided procedures. The algorithm has been developed to capitalize on the information generated by a laser range scanner. The current iteration of the algorithm is optimized for cortical surface registration. Intra-modality validation for the algorithm is provided in both physical and imaging phantoms. The physical phantom is generated using a laser range scanner that reports texture coordinates. The imaging phantom is generated from gadolinium enhanced MR volumes of the brain. Simulated inter-modality registration experiments on a cortical surface are also presented. Results of the experiments show successful registration accuracies on the order of the resolution of the surfac...
Ecological feminists have identified a conceptual dualism in western philosophy and religion. According to their analyses, this dualism is a conceptual structure which supports gender, racial and ethnic oppression and the exploitation of the non-human beings. They argue that, within this dualism, the body is denigrated as inferior to and separate from the mind. Although this critique of dualism invites an exploration of the relation between mind and body (also human and nature), ecological feminists want to avoid biological reductionism and holism. Maurice Merleau-Ponty and his notion of the flesh is one understanding of the mind-body relation that can help ecological feminists formulate an alternative to dualism. Merleau-Pontys sense phenomenology and his axiom of the flesh, developed in the posthumously published The Visible and Inv...
The role of communication among mobile robots remains one of the most important issues in multi-agent robotics system design. There are many research groups currently working on communication and cooperation among robots. Cooperation requires communication whenever ones actions depend critically on the knowledge that is accessible only from others. In the Intelligent Robotics Laboratory at Vanderbilt University, we are currently developing a method for robots to communicate and share knowledge with each other. We have developed the concept of the Peer Agent that will enable robots to exchange information between one another. The research experiment, described in this thesis, involved two mobile robots; Skeeter, a Pioneer 2-AT robot and Scooter, an ATRV-Jr robot. We will show that knowledge sharing through Peer Agents can lead to a more...
A factor that has long been identified as promoting peace between states is intergovernmental organizations (IGOs). From Kantian musings to Wilsonian idealism, international organizations have been seen as mechanisms for states to reach out of their inherent confines of self-interest and militant propensities to realize peace. The extant literature paints IGOs with a broad brush, and treats IGOs as if they all have the same ability to impact states conflict propensities. This analysis, however, posits that the type of IGO has a significant relationship with the prevention and de-escalation of militarized conflict. Through the conduct of this research, I uncover a number of substantive findings. First, I have upheld and extended the finding that shared memberships reduce chances of militarized disputes. Second, I have shown that univers...
This dissertation is a genealogical examination of the construction, representation, and disputation surrounding the meaning of sexual acts identified under the rubric of sadomasochism. I argue for an enlargement and expansion of the question, "What is masochism and what it means" and suggest that the polysemic text of contemporary S/M be accorded a measure of interpretive understanding in the light of a liberal, humanistic, and democratic notion of sexual freedom. The analysis begins with the descriptions of masochistic and sadistic behaviors initially identified and portrayed within the discourses of psychoanalysis and criminology. I argue that the disparate and distinct literatures and behaviors of masochism and sadism make the struggle for consensus about meaning nearly impossible. The study therefore proceeds with the analysis foc...
A method to enhance the performance and stability of haptic interfaces is addressed. This research approaches the control of haptic interfaces using classical control techniques, addressing both the performance and stability from a frequency domain perspective. Using linear time invariant models for the human and haptic interfaces, a controller is designed to enhance both the performance and stability robustness of the system. By approaching the control design in the frequency domain, stability can be addressed at the gain crossover frequency only and the rest of the frequency space can be used to address performance. The proposed approach is experimentally compared to other approaches on a 3 DOF haptic interface.
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