Month: September 2022

The big idea: why relationships are the key to existence

from Helgoland: Making Sense of the Quantum Revolution by Carlo Rovelli

From subatomic particles to human beings, interaction is what shapes reality (…)

Perhaps this is precisely what “properties” are: the effects of interactions. A good scientific theory, then, should not be about how things “are”, or what they “do”: it should be about how they affect one another. (…)

Reality is not a collection of things, it’s a network of processes. If this is correct, I think it comes with a lesson. We understand reality better if we think of it in terms of interactions, not individuals. 

Read the full article at: www.theguardian.com

Optimal transport and control of active drops

Suraj Shankar, Vidya Raju, and L. Mahadevan

PNAS

Transportation, in its broadest sense, is an important task in many fields, including engineering, physics, biology, and economics, and a great deal is known about optimal and efficient strategies to move matter, energy, and information around. But can we craft similar optimal protocols to transport autonomously moving (active) matter, such as self-propelled drops or migrating cells? We develop an optimal control framework to transport active fluid drops with the least amount of energy dissipated, by manipulating the spatio-temporal profile of its internal active stresses. By combining numerical solutions and analytical insight, we uncover simple principles and characteristic trade-offs that govern the optimal policies, suggesting general strategies for optimal transportation in a wide variety of synthetic and biological active systems.

Read the full article at: www.pnas.org

Collective memory in the digital age

Taha Yasseri, Patrick Gildersleve, Lea David

Progress in Brain Research

The digital transformation of our societies particulary driven by information and communication technologies have revolutionized how we generate, communicate, and acquire information. Collective memory as a core and unifying force in our societies has not been an exception among many societal concepts which have been revolutionized through this digital transformation. In this chapter, we have distinguished between “digitalized collective memory” and “collective memory in the digital age”. In addition to discussing these two main concepts, we discuss how digital tools and trace data can open doorways into the study of collective memory that is formed inside and outside of the digital space.

Read the full article at: www.sciencedirect.com

Multilayer Network Science

Oriol Artime, Barbara Benigni, Giulia Bertagnolli, Valeria d’Andrea, Riccardo Gallotti, Arsham Ghavasieh, Sebastian Raimondo, and Manlio De Domenico

Networks are convenient mathematical models to represent the structure of complex systems, from cells to societies. In the last decade, multilayer network science – the branch of the field dealing with units interacting in multiple distinct ways, simultaneously – was demonstrated to be an effective modeling and analytical framework for a wide spectrum of empirical systems, from biopolymers networks (such as interactome and metabolomes) to neuronal networks (such as connectomes), from social networks to urban and transportation networks. In this Element, a decade after one of the most seminal papers on this topic, the authors review the most salient features of multilayer network science, covering both theoretical aspects and direct applications to real-world coupled/interdependent systems, from the point of view of multilayer structure, dynamics and function. The authors discuss potential frontiers for this topic and the corresponding challenges in the field for the next future.

More at: www.cambridge.org

How Lévy Flights Triggered by the Presence of Defectors Affect Evolution of Cooperation in Spatial Games

Genki Ichinose, Daiki Miyagawa, Erika Chiba, Hiroki Sayama
Artificial Life

Cooperation among individuals has been key to sustaining societies. However, natural selection favors defection over cooperation. Cooperation can be favored when the mobility of individuals allows cooperators to form a cluster (or group). Mobility patterns of animals sometimes follow a Lévy flight. A Lévy flight is a kind of random walk but it is composed of many small movements with a few big movements. The role of Lévy flights for cooperation has been studied by Antonioni and Tomassini, who showed that Lévy flights promoted cooperation combined with conditional movements triggered by neighboring defectors. However, the optimal condition for neighboring defectors and how the condition changes with the intensity of Lévy flights are still unclear. Here, we developed an agent-based model in a square lattice where agents perform Lévy flights depending on the fraction of neighboring defectors. We systematically studied the relationships among three factors for cooperation: sensitivity to defectors, the intensity of Lévy flights, and population density. Results of evolutionary simulations showed that moderate sensitivity most promoted cooperation. Then, we found that the shortest movements were best for cooperation when the sensitivity to defectors was high. In contrast, when the sensitivity was low, longer movements were best for cooperation. Thus, Lévy flights, the balance between short and long jumps, promoted cooperation in any sensitivity, which was confirmed by evolutionary simulations. Finally, as the population density became larger, higher sensitivity was more beneficial for cooperation to evolve. Our study highlights that Lévy flights are an optimal searching strategy not only for foraging but also for constructing cooperative relationships with others.

Read the full article at: direct.mit.edu