John Sebastian
@johnseb.bsky.social
Fluid Mechanics, etc
https://john-seb.github.io/
https://john-seb.github.io/
Reposted by John Sebastian
Including this mass asymmetry in the reduced order model produces a system which is related to the 4D Lorenz system, or the Malkus-Robbins system. Because so much is known about the Lorenz system, these connections allow us to predict behavior transition (bifurcation) times, and more. (7/10)
August 21, 2026 at 2:00 PM
Including this mass asymmetry in the reduced order model produces a system which is related to the 4D Lorenz system, or the Malkus-Robbins system. Because so much is known about the Lorenz system, these connections allow us to predict behavior transition (bifurcation) times, and more. (7/10)
Reposted by John Sebastian
The molecular origin of this rapid softening remains unknown. Future studies and new genetic tools are needed to uncover the signals driving the ultra-fast mechanical remodeling of the cell wall.
Full paper in @science.org:
www.science.org/doi/10.1126/...
Full paper in @science.org:
www.science.org/doi/10.1126/...
Fast cell wall softening causes Venus flytrap closure
Plants can move rapidly without muscles, as seen in the Venus flytrap’s snapping lobes—a long-standing puzzle in plant biomechanics. Trap closure involves an elastic instability, but the active mechan...
www.science.org
June 13, 2026 at 2:19 PM
The molecular origin of this rapid softening remains unknown. Future studies and new genetic tools are needed to uncover the signals driving the ultra-fast mechanical remodeling of the cell wall.
Full paper in @science.org:
www.science.org/doi/10.1126/...
Full paper in @science.org:
www.science.org/doi/10.1126/...
Reposted by John Sebastian
Comics by Caroline Hu here
March 11, 2026 at 6:53 PM
Comics by Caroline Hu here
Reposted by John Sebastian
I decided to highlight this study for two reasons:
1) It is fun. There's an experiment involving "pencil gladiators." And spikes across scale. Need I say more.
2) It's a good reminder that not everything in biology exists to serve some evolutionary purpose. Biology is also physics.
1) It is fun. There's an experiment involving "pencil gladiators." And spikes across scale. Need I say more.
2) It's a good reminder that not everything in biology exists to serve some evolutionary purpose. Biology is also physics.
March 10, 2026 at 3:39 PM
I decided to highlight this study for two reasons:
1) It is fun. There's an experiment involving "pencil gladiators." And spikes across scale. Need I say more.
2) It's a good reminder that not everything in biology exists to serve some evolutionary purpose. Biology is also physics.
1) It is fun. There's an experiment involving "pencil gladiators." And spikes across scale. Need I say more.
2) It's a good reminder that not everything in biology exists to serve some evolutionary purpose. Biology is also physics.
Reposted by John Sebastian
To make a long story short: the universal stabby curve cometh from mechanical weathering.
It is not some evolved optimum solution for stabbing, it is just the shape you get if you expose a pointy thing to the elements for long enough.
It is not some evolved optimum solution for stabbing, it is just the shape you get if you expose a pointy thing to the elements for long enough.
March 10, 2026 at 3:39 PM
To make a long story short: the universal stabby curve cometh from mechanical weathering.
It is not some evolved optimum solution for stabbing, it is just the shape you get if you expose a pointy thing to the elements for long enough.
It is not some evolved optimum solution for stabbing, it is just the shape you get if you expose a pointy thing to the elements for long enough.
Reposted by John Sebastian
Very cool! It always amazes me how different problems can look very similar once put into equations. The sublimation of sharp tips also yields a curvature decreasing as t^(-1/2) because the receding velocity scales with the curvature locally (doi.org/10.1038/s414...).
March 9, 2026 at 4:01 PM
Very cool! It always amazes me how different problems can look very similar once put into equations. The sublimation of sharp tips also yields a curvature decreasing as t^(-1/2) because the receding velocity scales with the curvature locally (doi.org/10.1038/s414...).
This is wonderful! Thanks for the link Etienne.
March 9, 2026 at 5:19 PM
This is wonderful! Thanks for the link Etienne.