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Posts by Roberto Álvarez

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Sea creatures reveal the physics behind animal body shape diversity | EMBL New study identifies ‘mechanotypes’ as the physical links between genes and body shapes, explaining how diverse forms arise in animals

D'Arcy Thompson tenia razón: Comparando 6 especies de cnidarios , descubieron que variaciones en pocos módulos mecánicos de tejido predicen la diversidad de formas larvarias. Alterando estos módulos, una forma de una especie para parecerse a otra. tinyurl.com/3xukwfcp Paper tinyurl.com/hbzsrmwn

3 weeks ago 0 0 0 0
Stochastic–dissipative least-action framework for self-organizing biological systems, Part I: Variational rationale and Lyapunov-type behavior How and why do complex chemical and biological systems self-organize into ordered states far from thermodynamic equilibrium? Despite advances in thermodynamics, kinetics, and information theory, a unifying principle that links organization and efficiency across scales has remained elusive. In open systems, productive-event trajectories are conditioned on starting at a source and ending at a sink. This work proposes a stochastic–dissipative least-action triad framework in which (i) a path-ensemble weighting biases trajectories by their action cost, (ii) feedback processes sharpen this distribution, and (iii) the ensemble evolves toward a least-average-action attractor, decreasing during self-organization and increasing during decay. A parametric cross-scale metric—Average Action Efficiency (AAE)—is defined, which is inversely proportional to the average action per productive event. Under reinforcing feedback, identities derived from the exponential-family path measure show that the average action decreases and AAE rises monotonically. In future extensions, this formulation could help bridge quantum, classical, and biological regimes while remaining computationally tractable, because its empirical version relies on aggregate energetic and timing data rather than enumerating individual trajectories. AAE reaches a local maximum at a non-equilibrium steady state under fixed operational context, consistent with the present formulation, and connections to thermodynamic and informational measures are made. A companion article (Part II) details empirical estimation strategies and applications (Georgiev, 2025a). Georgi Yordanov Georgiev BioSystems Volume 262, April 2026, 105647 Read the full article at: www.sciencedirect.com See Also: Part II: Empirical estimation, Average Action Efficiency, and applications to ATP synthase

Stochastic–dissipative least-action framework for self-organizing biological systems, Part I: Variational rationale and Lyapunov-type behavior - ScienceDirect

1 month ago 1 1 0 0
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Emergence of the Golden Angle in Flower Heads Phyllotaxis—the arrangement of plant organs around their supporting axes—is an important attribute of plant architecture. Recent experimental data show that the first phase of typical phyllotactic ...

Emergence of the Golden Angle in Flower Heads www.tandfonline.com/doi/full/10....

2 months ago 1 0 0 0

Catástrofes para pensar lo social: Thom, entre geometría, sentido y cambios bruscos fgbueno.es/bas/pdf/bas1...

2 months ago 1 0 0 0
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Why life is hot The process of evolution by natural selection leads to fitness-maximising phenotypes. On the level of cellular chemical reaction networks, maximising fitness can mean optimising a variety of fitness f...

What a great paper. Wilson Poon & colleagues argue that life isn't exactly trying to be energetically efficient, because it needs the heat to optimize other capabilities.
www.arxiv.org/abs/2512.04725

4 months ago 33 7 0 1
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Caminar en Querétaro: un acto de resistencia en una ciudad diseñada para el automóvil - Tribuna de Querétaro En una ciudad que crece a ritmo acelerado, caminar debería ser un derecho, no un riesgo. Sin embargo

search.app/TZhhp

4 months ago 1 0 0 0

Por cierto, ¿en dónde celebran los queretanos?

5 months ago 1 0 1 0
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What is the origin of diversity in allometric laws scaling across species? Check our new paper led by Andrea Tabi where
we propose a new theory of metabolic scaling grounded in thermodynamics and stochastic fluctuations at the cellular level.
www.biorxiv.org/content/10.1...

5 months ago 44 14 0 0
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x.com/fciencias/st...

5 months ago 2 0 0 0
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The Quarterly Review of Biology: QRB 100th Anniversary

The Quarterly Review of Biology turns 100! We are celebrating our anniversary with free-to-read articles from the archives, through 2026. Learn more: ow.ly/xXli50X7Z5B

6 months ago 18 8 1 3
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In #drylands, plants don’t grow randomly — they self-organize into disordered hyperuniform patterns that help them use water wisely & endure extreme aridity. A beautiful hidden logic of nature, revealed in a new @pnas.org study doi.org/10.1073/pnas... including #Maestrelab alumni

6 months ago 60 25 1 2

No, no tienen cuenta aqui

6 months ago 0 0 0 0

En la FCN-UAQ hay varixs expertxs de plantas nativas: Mahinda Martínez y Díaz de Salas, Luis Hernández Sandoval y Rolando Tenoch Bárcenas.

6 months ago 1 0 1 0
Panel 1
A figure lies on a lounger as a hot, orange sun sets, saying
"The holiday's over."

Panel 2
Now wheeling a suitcase towards a plane in  warm eveniong light
"It's nice to sit around in the sun reading all day."

Panel 3
The plane rises amongst the clouds
"But all good things must come to an end."

Panel 4
The figure deplanes with the suitcase in drizzle
"Coming home has its own pleasures."

Panel 5
The rain is harder. The figure shelter under an umbrella and looks into a shop window containing a selection of books and a sign reading
"New books for autumn!"

Panel 6
The figure now sits at home by an open fire, happily reading a new book. The suitcase has not yet been unpacked.

Panel 1 A figure lies on a lounger as a hot, orange sun sets, saying "The holiday's over." Panel 2 Now wheeling a suitcase towards a plane in warm eveniong light "It's nice to sit around in the sun reading all day." Panel 3 The plane rises amongst the clouds "But all good things must come to an end." Panel 4 The figure deplanes with the suitcase in drizzle "Coming home has its own pleasures." Panel 5 The rain is harder. The figure shelter under an umbrella and looks into a shop window containing a selection of books and a sign reading "New books for autumn!" Panel 6 The figure now sits at home by an open fire, happily reading a new book. The suitcase has not yet been unpacked.

My cartoon for the @theguardian.com books autumn reads special.

7 months ago 1008 316 5 18
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Why is universality such a central concept in complex systems? How does it connect Turing Machines and Spin Systems? In this new paper, Tomáš Gonda and @gemmadlc.bsky.social present an accessible account on how to identify and compare different universalities arxiv.org/pdf/2406.16607

7 months ago 17 4 0 0
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What do Pac-Man, Space Invaders, and Mortal Kombat have to teach us about #cultural #evolution? As a social-technological phenomenon, #arcade game genres evolved like cultural species—some diversified, while others became "living fossils." 🕹️🧪 👉 doi.org/10.1017/ehs....

8 months ago 67 24 6 5
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Ya está abierto el registro para asistir al Segundo Encuentro de la Red Mexicana de Biología y Matemáticas redmexbiomate.org.mx Nos vemos en Querétaro en Noviembre!

8 months ago 4 2 0 0
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What is emergence? This is one of the most central ingredients of complexity, and a challenging one to formalize. Here's a paper by @seanmcarroll.bsky.social & Achyth Parola that attempts to classify different forms of emergence. @manlius.bsky.social @sfiscience.bsky.social arxiv.org/pdf/2410.15468

8 months ago 155 41 7 3
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Are there universal principles for the structural limits of living organisms? How can physics provide a theory? Check this @pnas.org paper that derives Kleiber’s law from 1st principles, capturing geometric differences and predicting life forms between plants & animals. www.pnas.org/doi/pdf/10.1...

8 months ago 20 5 0 1
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For the record, there's no point inviting me to give any talks or attend any conferences in the US for the foreseeable future. Sorry, but it's really not worth the risk.

9 months ago 139 13 6 1
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"we can safely assess that there were no lasagne encoded in the Big Bang"

royalsocietypublishing.org/doi/full/10....

10 months ago 38 8 1 2

Jajaja, pues sí, ¡qué raro está ese temario! ¿.Qué materia es? ¿De qué licenciatura?

10 months ago 0 0 1 0

Suena como a una clase de fenómeno de percolación

10 months ago 1 0 1 0

Supongo que las avalanchas de rocas y de neuronas son fenómenos muy distintos.

10 months ago 0 0 1 0

Órale qué interesante! La hipótesis que el cerebro está en una zona crítica se basa en la medición de la frecuencia y tamaño de avalanchas neuronales.

10 months ago 0 0 1 0

¿Por qué te lo recomendó y qué te hizo pensar ahora en esa recomendación ?

10 months ago 0 0 1 0
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Más de 30 muertos, la mitad de ellos niños, al bombardear Israel un colegio que servía de refugio en Gaza El Gobierno de Netanyahu se ufana de haber golpeado 200 objetivos “terroristas” en 48 horas y el ejército anuncia un inminente “ataque sin precedentes”

Israel ha matado en la madrugada de este lunes, mientras dormían, al menos a 36 personas —18 de ellas, niños de corta edad— al bombardear una escuela que se había convertido en refugio para desplazados

10 months ago 109 131 15 15
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'Amores perros' a un cuarto de siglo de distancia. Para La Jornada, escribí en su momento este recuento celebrando al choque que abrió el siglo II del cine nacional.

Les invito a leer en 👉 shorturl.at/K5fyH

11 months ago 6 2 0 0

¡No he visto eso! En donde vivo, el servicio ya está privatizado y, además de ser costoso, aplican cobros arbitrarios por situaciones como el cambio de medidor, aunque esté en buen estado. Lo reemplazan sin previo aviso solo para generar cargos adicionales.

11 months ago 1 0 1 0

De acuerdo. La inexistencia de espacios públicos. El modelo del mall como espacio "público" y de convivencia.

11 months ago 2 0 1 0