Gemunu H. Gunaratne

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An analysis of stationary and nonstationary cellular patterns observed in premixed flames on a circular, porous plug burner is presented. A phenomenological model is introduced, that exhibits patterns similar to the experimental states. The primary modes of the model are combinations of Fourier–Bessel functions, whose radial parts have neighboring zeros.(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)
The ability of Karhunen-Loève ͑KL͒ decomposition to identify, extract, and separate the spatial features that characterize a spatiotemporal system is demonstrated using video images from a combustion experiment and nonstationary states from a phenomenological model. Cellular flames on a circular porous plug burner exhibit a variety of stationary and(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)
Inner porous regions play a critical role in the load bearing capability of large bones. We show that an extension of disordered elastic networks [Chung et. al., Phys. Rev. B, 54, 15094 (1996)] exhibits analogs of several known mechanical features of bone. The " stress-backbones " and histograms of stress distributions for healthy and weak networks are(More)
We use Karhunen–Loeve ͑KL͒ decomposition of video images from an experiment to analyze a spatiotemporal dynamic state, unique to cellular flames, referred to as a ''hopping state.'' Ordered states of cellular flames on a circular burner consist of one or two concentric rings of luminous cells. The hopping states correspond to the motions of individual cells(More)
Early and accurate diagnoses of cancer can significantly improve the design of personalized therapy and enhance the success of therapeutic interventions. Histopathological approaches, which rely on microscopic examinations of malignant tissue, are not conducive to timely diagnoses. High throughput genomics offers a possible new classification of cancer(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)
An algorithm is presented to integrate nonlinear partial differential equations, which is particularly useful when accurate estimation of spatial derivatives is required. It is based on an analytic approximation method, referred to as distributed approximating functionals (DAF's), which can be used to estimate a function and a finite number of derivatives(More)