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DTSTAMP:20261019T095215Z
LAST-MODIFIED:20160613T135918Z
DTSTART:20160622T143000Z
DTEND:20160622T153000Z
UID:event1617@bu.edu
URL:http://physics.bu.edu/internal/events/show/1617
SUMMARY:Gabriel Birzu - Hidden Phase Transitions in Reaction-Diffusion Wave
	s
DESCRIPTION:Featuring Gabriel Birzu\n\nPart of the Preliminary Oral Exam.\n
	\nAbstract:\n\nTraveling waves in reaction-diffusion models describe a wide
	 range of phenomena: from combustion in physics to invasion of foreign spec
	ies in population biology. All such waves can be classified as either pulle
	d or pushed depending on how the growth rate depends on population density.
	 The propagation of pulled waves is controlled by the fast reproduction at 
	the leading edge\, while pushed waves advance via the "spill-over" of the g
	rowth in the bulk. This classification captures major differences in the pr
	operties of pulled and pushed waves including the expansion velocity and th
	e shape of the expansion profile. However\, the internal dynamics inside th
	e wave\, such as the loss of genetic diversity\, are also important in many
	 applications. We find that the rate of diversity loss divides pushed waves
	 into two distinct subclasses. For strongly pushed waves\, the lifetime of 
	a genetic polymorphism is proportional to the population density. In contra
	st for weakly pushed waves\, this dependence is a sub-linear power law\, wi
	th the exponent controlled solely by the distance to the universality class
	 of pulled waves. Other aspects of internal dynamics further demonstrate th
	at not all pushed waves are the same. Our results are a striking example of
	 how ecological properties of the species such the density-dependence of it
	s growth modulate the course of evolution by altering the amount of genetic
	 diversity. The differences in the adaptive potential of the two subclasses
	 of pushed waves have important implications for pest management\, control 
	of invasive species\, and cancer progression.
LOCATION:SCI 352\, 590 Commonwealth Avenue\, 02215
STATUS:CONFIRMED
CLASS:PUBLIC
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