Angler Perception and Population Dynamics of the Northern Snakehead (Channa argus) in the Potomac River & Tributaries

Our research sought to address the extent to which the northern snakehead (Channa argus), an invasive fish species, represents a threat to the Potomac River ecosystem. The first goal of our research was to survey the perceptions and opinions of recreational anglers on the effects of the snakehead population in the Potomac River ecosystem. To determine angler perceptions, we created and administered 113 surveys from June – September 2014 at recreational boat ramps along the Potomac River. Our surveys were designed to expand information collected during previous surveys conducted by the U.S. Fish and Wildlife Service. Our results indicated recreational anglers perceive that abundances and catch rates of target species, specifically largemouth bass, have declined since snakehead became established in the river. The second goal of our research was to determine the genetic diversity and potential of the snakehead population to expand in the Potomac River. We hypothesized that the effective genetic population size would be much less than the census size of the snakehead population in the Potomac River. We collected tissue samples (fin clippings) from 79 snakehead collected in a recreational tournament held between Fort Washington and Wilson’s Landing, MD on the Potomac River and from electrofishing sampling conducted by the Maryland Department of Natural Resources in Pomonkey Creek, a tributary of the Potomac River. DNA was extracted from the tissue samples and scored for 12 microsatellite markers, which had previously been identified for Potomac River snakehead. Microsatellite allele frequency data were recorded and analyzed in the software programs GenAlEx and NeEstimator to estimate heterozygosity and effective genetic population size. Resampling simulations indicated that the number of microsatellites and the number of fish analyzed provided sufficient precision. Simulations indicated that the effective population size estimate would expect to stabilize for samples > 70 individual snakehead. Based on a sample of 79 fish scored for 12 microsatellites, we calculated an Ne of 15.3 individuals. This is substantially smaller than both the sample size and estimated population size. We conclude that genetic diversity in the snakehead population in the Potomac River is low because the population has yet to recover from a genetic bottleneck associated with a founder effect due to their recent introduction into the system.

Action and perception: Neural indices of learning in infants

Early human development offers a unique perspective in investigating the potential cognitive and social implications of action and perception. Specifically, during infancy, action production and action perception undergo foundational developments. One essential component to examine developments in action processing is the analysis of others’ actions as meaningful and goal-directed. Little research, however, has examined the underlying neural systems that may be associated with emerging action and perception abilities, and infants’ learning of goal-directed actions. The current study examines the mu rhythm—a brain oscillation found in the electroencephalogram (EEG)—that has been associated with action and perception. Specifically, the present work investigates whether the mu signal is related to 9-month-olds’ learning of a novel goal-directed means-end task. The findings of this study demonstrate a relation between variations in mu rhythm activity and infants’ ability to learn a novel goal-directed means-end action task (compared to a visual pattern learning task used as a comparison task). Additionally, we examined the relations between standardized assessments of early motor competence, infants’ ability to learn a novel goal-directed task, and mu rhythm activity. We found that: 1a) mu rhythm activity during observation of a grasp uniquely predicted infants’ learning on the cane training task, 1b) mu rhythm activity during observation and execution of a grasp did not uniquely predict infants’ learning on the visual pattern learning task (comparison learning task), 2) infants’ motor competence did not predict infants’ learning on the cane training task, 3) mu rhythm activity during observation and execution was not related to infants’ measure of motor competence, and 4) mu rhythm activity did not predict infants’ learning on the cane task above and beyond infants’ motor competence. The results from this study demonstrate that mu rhythm activity is a sensitive measure to detect individual differences in infants’ action and perception abilities, specifically their learning of a novel goal-directed action.

Afro-Cuban Bata Drum Aesthetics: Developing Individual and Group Technique, Sound and Identity

The Lucumi religion (also Santeria and Regla de Ocha) developed in 19th-century colonial Cuba, by syncretizing elements of Catholicism with the Yoruba worship of orisha. When fully initiated, santeros (priests) actively participate in religious ceremonies by periodically being possessed or "mounted" by a patron saint or orisha, usually within the context of a drumming ritual, known as a toque de santo, bembe, or tambor. Within these rituals, there is a clearly defined goal of trance possession, though its manifestation is not the sole measure of success or failure. Rather than focusing on the fleeting, exciting moments that immediately precede the arrival of an orisha in the form of a possession trance, this thesis investigates the entire four- to six-hour musical performance that is central to the ceremony. It examines the brief pauses, the moments of reduced intensity, the slow but deliberate build-ups of energy and excitement, and even the periods when novices are invited to perform the sacred bata drums, and places these moments on an equal footing with the more dynamic periods where possession is imminent or in progress. This document approaches Lucumi ritual from the viewpoint of bata drummers, ritual specialists who, during the course of a toque de santo, exercise wide latitude in determining the shape of the event. Known as omo Ana (children of the orisha Ana who is manifest in drums and rhythms), bata drummers comprise a fraternity that is accessible only through ritual initiation. Though they are sensitive to the desires of the many participants during a toque de santo, and indeed make their living by satisfying the expectations of their hosts, many of the drummers' activities are inwardly focused on the cultivation and preservation of this fraternity. Occasionally interfering with spirit possession, and other expectations of the participants, these aberrant activities include teaching and learning, developing group identity or signature sound, and achieving a state of intimacy among the musicians known as "communitas."

Studies on Understanding Individual Willingness to Disclose Genetic Information to Public and Private Stakeholders

While technologies for genetic sequencing have increased the promise of personalized medicine, they simultaneously pose threats to personal privacy. The public’s desire to protect itself from unauthorized access to information may limit the uses of this valuable resource. To date, there is limited understanding about the public’s attitudes toward the regulation and sharing of such information. We sought to understand the drivers of individuals’ decisions to disclose genetic information to a third party in a setting where disclosure potentially creates both private and social benefits, but also carries the risk of potential misuse of private information. We conducted two separate but related studies. First, we administered surveys to college students and parents, to determine individual attitudes toward and inter-generational influences on the disclosure decision. Second, we conducted a game-theory based experiment that assessed how participants’ decisions to disclose genetic information are influenced by societal and health factors. Key survey findings indicate that concerns about genetic information privacy negatively impact the likelihood of disclosure while the perceived benefits of disclosure and trust in the institution receiving the information have a positive influence. The experiment results also show that the risk of discrimination negatively affects the likelihood of disclosure, while the positive impact that disclosure has on the probability of finding a cure and the presence of a monetary incentive to disclose, increase the likelihood. We also study the determinants of individuals’ decision to be informed of findings about their health, and how information about health status is used for financial decisions.