scholarly journals The propagation of active-passive interfaces in bacterial swarms

2018 ◽  
Author(s):  
Alison E. Patteson ◽  
Arvind Gopinath ◽  
Paulo E. Arratia

Propagating interfaces are ubiquitous in nature, underlying instabilities and pattern formation in biology and material science. Physical principles governing interface growth are well understood in passive settings; however, our understanding of interfaces in active systems is still in its infancy. Here, we study the evolution of an active-passive interface using a model active matter system, bacterial swarms. We use ultra-violet light exposure to create compact domains of passive bacteria withinSerratia marcescensswarms, thereby creating interfaces separating motile and immotile cells. Post-exposure, the boundary re-shapes and erodes due to self-emergent collective flows. We demonstrate that the active-passive boundary acts as a diffuse interface with mechanical properties set by the flow. Intriguingly, interfacial velocity couples to local swarm speed and interface curvature, suggesting that an active analogue to classic Gibbs-Thomson-Stefan conditions controls boundary propagation. Our results generalize interface theories to mixing and segregation in active systems with collective flows.

2021 ◽  
Author(s):  
Ranajoy Bhattacharya ◽  
Mason Canon ◽  
Nedeljko Karaulac ◽  
Girish Rughoobur ◽  
Winston Chern ◽  
...  

2008 ◽  
Vol 40 (Supplement) ◽  
pp. S297
Author(s):  
Madhukar B. Kolli ◽  
Hideyo Takatsuki ◽  
Devashish Desai ◽  
Kevin M. Rice ◽  
Sunil Kakarla ◽  
...  

2010 ◽  
Vol 636-637 ◽  
pp. 1228-1233
Author(s):  
Olga Rodríguez ◽  
M.I. Sánchez de Rojas ◽  
M. Frías ◽  
A.R. Costa

The building materials used as a coating on the walls are exposed at different conditions of the weather for long periods of time, reason why is very important to determine the effects of sunlight, heat, humidity and other effects of climate change in the colour and the properties of these materials. In this work was carried out a study on the behaviour of colour and gloss of white cement with some different industrial waste additions submitted to ultra-violet light exposure. The addition of the different materials employed in this work does not modify lightness or chromatic coordinates after the exposure at ultraviolet light, however reduces significantly the gloss of the samples, including white Portland cement.


BMJ ◽  
1925 ◽  
Vol 1 (3364) ◽  
pp. 1152-1153
Author(s):  
A. Blakiston

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