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Ricard Alert Zenón

@ricardalert.bsky.social
1.1K followers 488 following 141 posts

ICREA Research Professor at Universitat de Barcelona. Research Group Leader at MPI-PKS and CSBD in Dresden. Theory of living matter. Collective phenomena in biology through the lens of active matter physics.

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Ricard Alert Zenón @ricardalert.bsky.social · 08/09/2026
New paper out @natcellbio.nature.com! In embryos, immune cell migration is guided by the surrounding tissue flow. In turn, tissue flow is captured by active wetting theory, generalized to include influx from the upper cell aggregate! Check the thread below! 👇 www.nature.com/articles/s41...
nature.com
Tissue flow acts as a guidance cue for immune cell polarization and directional migration - Nature Cell Biology
Le et al. show that in Xenopus embryos, local ectodermal tissue flows provide a directional cue that polarizes and guides embryonic myeloid cells migration via cell-on-cell interactions.
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Ricard Alert Zenón @ricardalert.bsky.social · 02/09/2026
New preprint! We found an active wetting transition in cell aggregates. We obtain an active Young-Dupré condition, which allows us to capture states of partial and complete wetting. With group members MJ Franco-Oñate and Hanno Hennighausen! arxiv.org/abs/2608.28912
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Nature Cell Biology @natcellbio.nature.com · 28/08/2026
☕Embryos from aged mice have increased contractility & tissue viscosity on E4.5, causing poor spreading and attachment. Similar age-associated mechanical changes in human embryos correlate with implantation potential. @katecavanaugh.bsky.social 👉https://rdcu.be/fCDVb www.nature.com/articles/s41...
nature.com
Elevated contractility drives implantation failure in mouse embryos from aged females - Nature Cell Biology
Cavanaugh et al. show that embryos from aged mice have increased contractility and tissue viscosity on embryonic day 4.5, which leads to poor spreading and attachment. Similar age-associated mechanica...
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Ricard Alert Zenón @ricardalert.bsky.social · 28/08/2026
New preprint! Motility-induced phase separation (MIPS) goes quantum! Great numerical work by Laurin Brunner, Reyhaneh Khasseh, and Markus Heyl to show MIPS in active hard-core bosons. Personally, excited about my first paper with ℏ≠0! arxiv.org/abs/2608.25649
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Ricard Alert Zenón @ricardalert.bsky.social · 25/08/2026
New paper @natcellbio.nature.com! We propose to understand embryo implantation as active wetting. Embryos from older mothers spread less because they are too contractile and viscous. Experiments by @katecavanaugh.bsky.social and theory by MJ Franco-Oñate in my group. www.nature.com/articles/s41...
nature.com
Elevated contractility drives implantation failure in mouse embryos from aged females - Nature Cell Biology
Cavanaugh et al. show that embryos from aged mice have increased contractility and tissue viscosity on embryonic day 4.5, which leads to poor spreading and attachment. Similar age-associated mechanica...
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Ricard Alert Zenón @ricardalert.bsky.social · 03/08/2026
New paper! Inspired by gliding bacteria, we introduce active screws: Particles that self-propel by spinning around their propulsion axis. We show that active screws form active chiral nematics. With Debu Banerjee and @lauritzh.bsky.social @mpipks.bsky.social journals.aps.org/prresearch/a...
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Ricard Alert Zenón @ricardalert.bsky.social · 12/06/2026
Our paper on a Hamiltonian description of non-reciprocal interactions is out @natphys.nature.com! With Yubo Shi, Roderich Moessner, and @marinbukov.bsky.social @mpipks.bsky.social @ub.edu @icreacommunity.bsky.social Check it out, and read more in the thread below! 👇 www.nature.com/articles/s41...
nature.com
Hamiltonian description of non-reciprocal interactions - Nature Physics
Many active and driven systems exhibit non-reciprocal interactions, making them hard to describe with standard methods. Now a constrained Hamiltonian embedding with auxiliary variables reproduces thes...
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Ricard Alert Zenón @ricardalert.bsky.social · 05/06/2026
New preprint! Interested in mechanical interactions between cells and the extracellular matrix? We studied the feedback between cellular traction forces and the ECM nonlinear elasticity. With Irina Pi-Jaumà and Jaume Casademunt. arxiv.org/abs/2606.03669
arxiv.org
Bistability of cellular traction on strain-stiffening substrates
To migrate, cells exert traction forces on the extracellular matrix (ECM) -- a biopolymer network that often exhibits nonlinear strain-stiffening elasticity. Cellular tractions can therefore stiffen t...
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Ricard Alert Zenón @ricardalert.bsky.social · 18/03/2026
Despite it being chaotic, active nematic turbulence can give rise to arrested labyrinthine patterns! Check out our new paper @physrevresearch.bsky.social! Work led by Ido Lavi, with Jean-François Joanny and Jaume Casademunt. journals.aps.org/prresearch/a...
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ICREA Community @icreacommunity.bsky.social · 11/02/2026
📰 Notícies, agenda científica, descobriments i entrevistes. ICREA't és el teu nou portal per seguir l'actualitat de les investigacions dels recercaires ICREA a Catalunya. No et perdis res 👉 icreat.cat
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Ricard Alert Zenón @ricardalert.bsky.social · 30/01/2026
New preprint! We show how mesoscopic nonequilibrium fluctuations in active gels emerge from the breaking of detailed balance at the molecular scale. Warning: Long technical paper ahead! Enjoy! @mpipks.bsky.social @ub.edu @ubics.bsky.social @icreacommunity.bsky.social arxiv.org/abs/2601.20483
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ICREA Community @icreacommunity.bsky.social · 17/12/2025
#NousICREAs2025 | 🧬 Ricard Alert @ricardalert.bsky.social (@ub.edu) investiga en física biològica. Estudia com les lleis de la física governen la vida, per exemple, investigant com cèl·lules i bacteris es mouen en grups. short.do/UBTLe-
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Ricard Alert Zenón @ricardalert.bsky.social · 17/12/2025
Our paper on the transition to active turbulence is now out @natcomms.nature.com! With @the-chaotician.bsky.social. Are you curious how activity begets chaos? Check out the paper and the thread below. 👇 www.nature.com/articles/s41...
nature.com
Discontinuous transition to active nematic turbulence - Nature Communications
Active fluids, such as bacterial suspensions, exhibit chaotic flows at low Reynolds number - a phenomenon known as active turbulence. Here, the authors show a discontinuous transition from laminar to ...
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Ricard Alert Zenón @ricardalert.bsky.social · 02/12/2025
New preprint! Do you like ocean waves? We found similar waves on bacterial colonies! We found that this collective behavior, known as rippling, is nothing but surface waves on an active nematic. @princeton.edu @mpipks.bsky.social @ub.edu @icreacommunity.bsky.social www.biorxiv.org/content/10.1...
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Ricard Alert Zenón @ricardalert.bsky.social · 02/12/2025
Super excited to start as an ICREA Research Professor at the University of Barcelona! Really happy to join fantastic colleagues at @icreacommunity.bsky.social and @ub.edu. www.icrea.cat/community/ic...
icrea.cat
ICREAs Fitxa - ICREA
Something went wrong
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Mariona Esquerda Ciutat @marionamec.bsky.social · 02/12/2025
🎧🎙Últim capítol de La utilitat del coneixement inútil! Parlem amb la @gmarfanyn.bsky.social sobre CRISPR i obrim el debat que hem de tenir tots de la millor manera: amb el coneixement científic a la mà! @soctastaolletes.bsky.social youtu.be/DUzzjkkUBT4?...
youtu.be
T1C7 Els bacteris, l’edició genètica i el Nobel robat, amb Gemma Marfany i Nadal
YouTube video by La Dimoni de Maxwell
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Giacomo Bartolucci (he) @gbart.bsky.social · 15/11/2025
Active droplets are fundamental in cell biology and origin of life. With Jonathan Bauermann, @boekhovenlab.bsky.social, Frank Jülicher, and @m-pol.bsky.social, we show that a critical transition influences their size, morphology, ripening and division propensity journals.aps.org/prx/abstract...
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Mariona Esquerda Ciutat @marionamec.bsky.social · 15/11/2025
🕵️ A qui t’agradaria conèixer? Amb quantes persones hi arribaries? El Ricard Solé @ricardsole.bsky.social, investigador ICREA a @upf.edu ens ho explica al nostre pòdcast! youtube.com/shorts/buG_R...
youtube.com
6 graus de separació #ciènciaencatalà #podcast #divulgaciócientífica #ciència
YouTube video by La Dimoni de Maxwell
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Mariona Esquerda Ciutat @marionamec.bsky.social · 28/10/2025
Escolta en nou capítol de La utilitat del coneixement inútil! Quàntica, ordinadors i espanta sogres!!! 🎉🥳
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David Brückner @davidbrueckner.bsky.social · 16/10/2025
🤔 Can tissue patterning & tumor heterogeneity emerge in a self-organized way? We show that self-organized mechanical stress & density gradients pattern tumors in vitro & in vivo, and this behavior is quantitatively predicted by a mechano-chemical active fluid model! Check out Carlos' thread ⬇️
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Carlos Pérez-González @cperez-gonzalez.bsky.social · 16/10/2025
1/ 🎉Excited to share our new preprint @vignjeviclab.bsky.social @davidbrueckner.bsky.social : "Self-organization of tumor heterogeneity and plasticity" biorxiv.org/content/10.1... Tumor heterogeneity and plasticity drive metastasis and relapse. How is tumor patterning coordinated? A thread👇
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Mariona Esquerda Ciutat @marionamec.bsky.social · 16/10/2025
🛰️ Sabies que fas servir la teoria de la relativitat cada cop que treus el GPS? Mira el 4t capítol de La utilitat del coneixement inútil per veure com li peta el cap a la @soctastaolletes.bsky.social 🤯 Amb un ajut @fcri.bsky.social open.spotify.com/episode/4lza...
open.spotify.com
Spotify – Web Player
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Ricard Alert Zenón @ricardalert.bsky.social · 02/10/2025
New job, new preprint! We found that embryo implantation can be understood as active wetting! Embryos from older mothers have trouble implanting because they are too contractile and viscous. Check out the wonderful thread (and movies!) by @katecavanaugh.bsky.social. www.biorxiv.org/content/10.1...
biorxiv.org
A mechanical origin for implantation defects in embryos from aged females
Women over 35 experience a marked reduction in fertility. The origin of these fertility defects appears to reside in the implantation capacity of the embryo itself, but the mechanistic basis of this i...
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Ricard Alert Zenón @ricardalert.bsky.social · 01/10/2025
Excited to be back in Barcelona @ub.edu to start a new chapter!
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Ricard Alert Zenón @ricardalert.bsky.social · 21/09/2025
Warm goodbye to Dresden's @mpipks.bsky.social, my scientific home for the past 4 years. It's been amazing to start my group here! Thanks to the Max Planck Society, group members and everyone at the institute! Looking forward to the new chapter in Barcelona @ub.edu
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Max Planck Institute for the Physics of Complex Systems @mpipks.bsky.social · 19/09/2025
IG Nobel Prize in #Physics 2025 to @mpipks.bsky.social researchers for elucidating the phase behaviour of cacio e pepe sauce. The work highlights how physics can also be applied to solve daily-life problems! nature.com/articles/d41586-025-03045-0
nature.com
Tipsy bats and perfect pasta: Ig Nobels celebrate ‘improbable’ research
The annual awards are a celebration of weird but thought-provoking science.
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Ricard Alert Zenón @ricardalert.bsky.social · 19/09/2025
Truly happy to see that our Italian colleagues @mpipks.bsky.social won the IgNobel Prize for figuring out that the Cacio e Pepe sauce can easily phase separate and become clumpy! Very well deserved! Congrats to the team! 😀
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Ricard Alert Zenón @ricardalert.bsky.social · 19/09/2025
Check our new preprint on active surface simulations of amoeboid migration! We show how this mode of migration can be mechanically guided by gradients in friction, viscosity, pressure, or confinement, and even by nearby cells. Work led by Hanna Gertack and Sebastian Aland. arxiv.org/abs/2509.11801
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Mariona Esquerda Ciutat @marionamec.bsky.social · 18/09/2025
🤔Què tenen en comú l’Ou com balla i un àtom? 🎙️El Lluís Torner, fundador de l’ICFO ens ho explica! 👉 Escolta el 2n capítol de La utilitat del coneixement inútil! Amb el suport d’un Ajut FCRI 2025 @fcri.bsky.social @soctastaolletes.bsky.social youtube.com/shorts/Al5mY...
youtube.com
L'àtom com balla!
YouTube video by La Dimoni de Maxwell
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Ricard Alert Zenón @ricardalert.bsky.social · 17/09/2025
Very honored to receive this prize from the Spanish Physical Society! Thanks a lot to all my collaborators, who make this possible!
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Max Planck Institute for the Physics of Complex Systems @mpipks.bsky.social · 16/09/2025
Bacteria are surrounded by water! New work @natphys.nature.com by @ricardalert.bsky.social @mpipks.bsky.social & collaborators @ Princeton University shows that water capillary forces organise bacterial colonies into gas, nematic streams, and droplet states. nature.com/articles/s41567-025-02965-y
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Ricard Alert Zenón @ricardalert.bsky.social · 27/08/2025
Our paper about active crystals is now out @softmatter.rsc.org! During the revisions, we added a section about triangular lattices, on which the turn-towards or turn-away interactions can be frustrated. Check it out, and see the post below! pubs.rsc.org/en/content/a... bsky.app/profile/rica...
pubs.rsc.org
Lattice-dependent orientational order in active crystals
Via mechanisms not accessible at equilibrium, self-propelled particles can form phases with positional order, such as crystals, and with orientational order, such as polar flocks. However, the interpl...
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Mariona Esquerda Ciutat @marionamec.bsky.social · 24/08/2025
Has intentat ma fer un gelat casolà i no ha sortit tan cremós com esperaves? T'han quedat uns cristalls que et trinxen les dents? 🍦☀️ A la @soctastaolletes.bsky.social i a mi ens ha passat, però tenim la solució... youtube.com/shorts/hAXjP...
youtube.com
Gelat de vidre
YouTube video by La Dimoni de Maxwell
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Ricard Alert Zenón @ricardalert.bsky.social · 02/08/2025
Dreaming of a swimming pool? Bacteria are surrounded by water! Water capillary forces organize bacterial colonies into gas, nematic streams, or droplet states. New paper @natphys.nature.com led by Matt Black and Chenyi Fei, with Ned Wingreen and Josh Shaevitz! www.nature.com/articles/s41...
nature.com
Capillary interactions drive the self-organization of bacterial colonies - Nature Physics
Bacteria tend to live in thin layers of water on surfaces. Now the capillary forces in these layers are shown to help organize the bacteria into dense packs.
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Ricard Alert Zenón @ricardalert.bsky.social · 25/06/2025
New preprint! When forming a crystal, active particles that turn either towards or away from each other end up aligning along directions determined by the crystalline lattice. In these active crystals, orientational and positional order are coupled. Work by Till Welker! arxiv.org/abs/2506.16501
arxiv.org
Lattice-dependent orientational order in active crystals
Via mechanisms not accessible at equilibrium, self-propelled particles can form phases with positional order, such as crystals, and with orientational order, such as polar flocks. However, the interpl...
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Max Planck Institute for the Physics of Complex Systems @mpipks.bsky.social · 17/06/2025
🐠🦠Why can’t bacteria swim like fish? At microscopic scales, physics changes — viscosity rules! Researchers at our institute study how microbes like E. coli overcome this challenge with clever strategies like run-and-tumble. Watch our new video: youtu.be/drwCRRD7CGY?...
youtu.be
Tiny swimmers
YouTube video by MPIPKS
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Mariona Esquerda Ciutat @marionamec.bsky.social · 17/06/2025
😊 I had so much fun making this video for @mpipks.bsky.social! Loved learning from Christina Kurzthaler how bacteria swim: it’s weird, clever, and totally different from what you'd expect! ✨I hope you enjoy it as much as I did!
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Ricard Alert Zenón @ricardalert.bsky.social · 10/06/2025
👉 New paper @physrevlett.bsky.social! Active nematics flow spontaneously, driven by their own constituents, e.g. molecular motors or cells. The transition to spontaneous flows was thought to be always continuous. We now discovered that it can also be discontinuous! journals.aps.org/prl/abstract...
journals.aps.org
Nonlinear Spontaneous Flow Instability in Active Nematics
Active nematics exhibit spontaneous flows through a well-known linear instability of the uniformly aligned quiescent state. Here, we show that even a linearly stable uniform state can experience a non...
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Mariona Esquerda Ciutat @marionamec.bsky.social · 28/05/2025
😊 I had the pleasure to turn this exciting @cellpress.bsky.social paper into a video-abstract. Check it out! youtu.be/0REvwcuOao8 Thanks to the authors for writing the script and to @hymanlab.bsky.social and to @mpi-cbg.de for sharing it!
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Mariona Esquerda Ciutat @marionamec.bsky.social · 27/05/2025
🎉 SO EXCITED to share this video I made about this super interesting research by @hymanlab.bsky.social at @mpi-cbg.de 🧪 They identified a molecule that can dissolve pathological stress granules associated with diseases like ALS!
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Campàs Lab @campaslab.bsky.social · 26/05/2025
We did it! 🎉 🍾🥂 Our Excellence Cluster Physics of Life (PoL) got renewed until 2032! I am so proud of our team and all the great work we did to achieve this.
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Physics of Life Dresden @poldresden.bsky.social · 26/05/2025
We're thrilled to announce that our Excellence Cluster Physics of Life (PoL) has been renewed for a second funding phase (2026-2032) by @dfg.de ! Thanks to everyone who made this possible! 🎉👏 We'll continue our cutting-edge research towards understanding what brings matter to life! #biophysics #dfg
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Ricard Alert Zenón @ricardalert.bsky.social · 09/05/2025
New preprint! Non-reciprocal interactions don’t arise from a potential. Yet, we found a way to encode them in a Hamiltonian, which captures the phase transitions of non-reciprocal systems! With Yubo Shi, Roderich Moessner, and @marinbukov.bsky.social @mpipks.bsky.social. arxiv.org/pdf/2505.05246
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Max Planck Institute for the Physics of Complex Systems @mpipks.bsky.social · 02/05/2025
How do cells rotate together on a sphere? In our new video abstract, we describe our recent work on how cells move on the surface of a sphere—as they do in development, wound healing, or regeneration. www.youtube.com/watch?v=d2Rn...
youtube.com
How do cells rotate together on a sphere?
YouTube video by MPIPKS
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Mariona Esquerda Ciutat @marionamec.bsky.social · 02/05/2025
✨So excited to share this! I had the pleasure of producing this video for the @mpipks.bsky.social about a recent paper on how cells rotate together on a sphere 🧫🪩 👉Check it out, it's a beautiful blend of physics and biology!
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Ricard Alert Zenón @ricardalert.bsky.social · 24/04/2025
Check out our new work @natcomms.nature.com! @mayorlab.bsky.social discovered that cells perform durotaxis even without focal adhesions. How? Well, we found that they actually follow friction gradients — a new mode of directed cell migration that we call frictiotaxis! www.nature.com/articles/s41...
nature.com
Frictiotaxis underlies focal adhesion-independent durotaxis - Nature Communications
Cells typically migrate toward stiffer substrates via durotaxis, relying on focal adhesions. Here, the authors show that confined cells can migrate up friction gradients without focal adhesions, revea...
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Max Planck Institute for the Physics of Complex Systems @mpipks.bsky.social · 18/03/2025
Our call for Postdoc Positions in Biological Physics is open! Join our exciting and stimulating environment, with a rich variety of groups to collaborate. Deadline for applications is 2nd of May! Apply here: www.pks.mpg.de/biological-p...
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Max Planck Institute for the Physics of Complex Systems @mpipks.bsky.social · 11/02/2025
🧲✨ Ever wondered what makes magnets magnetic, or how superconductivity works? 🎥 Check out our new video by @marionamec.bsky.social, where the group of @awietek.bsky.social at @mpipks.bsky.social dives into these and other fascinating states of matter! With support of @dfg.de youtu.be/nY9_dIpJoJM?...
youtu.be
SuMaC: From Magnets to Superconductors
YouTube video by MPIPKS
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Ricard Alert Zenón @ricardalert.bsky.social · 23/01/2025
New paper @naturecomms.bsky.social! How do cells form new layers? In colonies of the motile bacterium Myxo, we find that layer formation is triggered by very strong fluctuations in traction forces. They are an order of magnitude larger than the average! www.nature.com/articles/s41...
nature.com
Local polar order controls mechanical stress and triggers layer formation in Myxococcus xanthus colonies - Nature Communications
The decision to form a fruiting body have been studied extensively, however, the mechanical events that trigger the creation of multiple cell layers is poorly understood. Here the authors find M. xant...
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Ricard Alert Zenón @ricardalert.bsky.social · 15/01/2025
New preprint! When and how do active flows become turbulent? We found that, in unconfined active nematics, the transition to turbulence is discontinuous! With @the-chaotician.bsky.social @mpipks.bsky.social arxiv.org/abs/2501.060...
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