Gemunu H. Gunaratne

Learn More
Drosophila adults, when placed into a novel open-field arena, initially exhibit an elevated level of activity followed by a reduced stable level of spontaneous activity and spend a majority of time near the arena edge, executing motions along the walls. In order to determine the environmental features that are responsible for the initial high activity and(More)
In open field arenas, Drosophila adults exhibit a preference for arena boundaries over internal walls and open regions. Herein, we investigate the nature of this preference using phenomenological modeling of locomotion to determine whether local arena features and constraints on movement alone are sufficient to drive positional preferences within open field(More)
In a seminal paper in 1973, Black and Scholes argued how expected distributions of stock prices can be used to price options. Their model assumed a directed random motion for the returns and consequently a lognormal distribution of asset prices after a finite time. We point out two problems with their formulation. First, we show that the option valuation is(More)
We study the arrangements of recurved bristles on the anterior wing margin of wild-type and mutant Drosophila. The epidermal or neural fate of a proneural cell depends on the concentrations of proteins of the achaete-scute complex. At puparium formation, concentrations of proteins are nearly identical in all cells of the anterior wing and each cell has the(More)
ii Acknowledgements No list that I may compile will include all the people who have, in some form or the other, contributed to this thesis. With apologies to all those who I may have inadvertently overlooked, I wish to thank, in particular, the following people: My thesis advisor, Professor Matthew J. Nicol, without whose guidance, extreme patience,(More)
Habituation is a common form of non-associative learning in which the organism gradually decreases its response to repeated stimuli. The decrease in exploratory activity of many animal species during exposure to a novel open field arena is a widely studied habituation paradigm. However, a theoretical framework to quantify how the novelty of the arena is(More)
Two families of statistical measures are used for quantitative characterization of nonequilibrium patterns and their evolution. The first quantifies the disorder in labyrinthine patterns, and captures features like the domain size, defect density, variations in wave number, etc. The second class of characteristics can be used to quantify the disorder in(More)
We present a class of statistical measures that can be used to quantify nonequilibrium surface growth. They are used to deduce information about spatiotemporal dynamics of model systems for spinodal decomposition and surface deposition. Pattern growth in the Cahn-Hilliard equation (used to model spinodal decomposition) are shown to exhibit three distinct(More)
  • 1