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UID:96c76054-230a-4520-a95e-a988cba5d91b@nexttoyou
DTSTAMP:20261105T161229Z
DTSTART:20261109T191000Z
DTEND:20261109T201000Z
SUMMARY:Physics Colloquium with Dr. Jay Tang
LOCATION:Innovation Hall 432\, 82 University Place\, Burlington\, VT 05405
DESCRIPTION:Active Matter Physics of Bacterial Swarms\n\nwith Dr. Jay Tang
 \nBrown University\n\nABSTRACT: On nutrient-rich substrates\, a droplet o
 f motile bacteria can grow into a large swarm. Swarming is a prevalent fo
 rm of bacterial collective motility\, often viewed as a precursor to biof
 ilms. The spreading of a bacterial swarm is facilitated by factors such a
 s osmolytes and biosurfactants\, secreted by the dense population of bact
 eria. Studying Pseudomonas aeruginosa\, a human pathogen known to swarm a
 nd form biofilms\, we identify and investigate a pattern that forms on th
 e outer edge of a large circular area within hours of growth\, i.e.\, a s
 olid-like ring of dense bacteria. As the swarm expands\, this ring stretc
 hes\, cracks inside out\, and breaks apart\, leading to broken sections a
 long the circumference and subsequently\, finger-shaped protrusions. We d
 eveloped a model based on the stress profile within the ring and applied 
 cracking mechanics to predict how the number of cracks formed varies with
  the radius of the swarm. Our work demonstrates that solid-like behavior 
 can play a dominant role in swarm morphology. This new mode of pattern de
 velopment differs from those based on instability at the fluid front\, wh
 ich can also form fingers and have been modeled previously. Taken togethe
 r\, we now recognize that dense bacterial swarms straddle between the flu
 id and solid states\, manifesting intricate properties of active matter w
 ith built-in growth and dynamics. Such dynamic states of bacteria are r\n
 \nhttp://next-to-u.app/events/96c76054-230a-4520-a95e-a988cba5d91b
URL:http://next-to-u.app/events/96c76054-230a-4520-a95e-a988cba5d91b
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