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A new theoretical framework for plastic neural networks predicts dynamical regimes where synapses rather than neurons primarily drive the network’s behavior, leading to an alternative candidate mechanism for working memory in the brain.

The brain is an immense network of neurons, whose dynamics underlie its complex information processing capabilities. A neuronal network is often classed as a complex system, as it is composed of many constituents, neurons, that interact in a nonlinear fashion (Fig. 1). Yet, there is a striking difference between a neural network and the more traditional complex systems in physics, such as spin glasses: the strength of the interactions between neurons can change over time. This so-called synaptic plasticity is believed to play a pivotal role in learning. Now David Clark and Larry Abbott of Columbia University have derived a formalism that puts neurons and the connections that transmit their signals (synapses) on equal footing [1]. By studying the interacting dynamics of the two objects, the researchers take a step toward answering the question: Are neurons or synapses in control?

Clark and Abbott are the latest in a long line of researchers to use theoretical tools to study neuronal networks with and without plasticity [2, 3]. Past studies—without plasticity—have yielded important insights into the general principles governing the dynamics of these systems and their functions, such as classification capabilities [4], memory capacities [5, 6], and network trainability [7, 8]. These works studied how temporally fixed synaptic connectivity in a network shapes the collective activity of neurons. Adding plasticity to the system complicates the problem because then the activity of neurons can dynamically shape the synaptic connectivity [9, 10].

A new theoretical framework for plastic neural networks predicts dynamical regimes where synapses rather than neurons primarily drive the network’s behavior, leading to an alternative candidate mechanism for working memory in the brain.

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Our universe is getting bigger and bigger really fast — something all the theories about space agree on, but none of them can totally explain. Now, there’s a new idea in town: Maybe our universe is expanding because it keeps bumping into and soaking up “baby” universes.

When scientists look at the afterglow of the Big Bang, known as the cosmic microwave background, they see that our universe is swelling up quicker and quicker. To make sense of this, physicists use something called the Standard Cosmological Model, which says there’s this weird stuff called dark energy pushing the universe to expand.

A team from the Dalian Institute of Chemical Physics made a breakthrough in converting methane to formic acid using oxygen at room temperature through a high-pressure electro-Fenton process, achieving significantly higher efficiency and productivity than traditional methods.

Direct conversion of methane (CH₄) and oxygen (O₂) to value-added chemicals is important for natural gas industries. However, challenges remain due to the difficulty of O₂ activation in forming active oxygen species for CH₄ activation under mild conditions.

Recently, a research group led by Prof. Dehui Deng, Assoc. Prof. Xiaoju Cui and Liang Yu from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) realized the electrochemical conversion of CH₄ by O₂ to formic acid (HCOOH) at room temperature. This study was published in the Journal of the American Chemical Society.

Birds flock. Locusts swarm. Fish school. Within assemblies of organisms that seem as though they could get chaotic, order somehow emerges. The collective behaviors of animals differ in their details from one species to another, but they largely adhere to principles of collective motion that physicists have worked out over centuries. Now, using technologies that only recently became available, researchers have been able to study these patterns of behavior more closely than ever before.

In this episode, the evolutionary ecologist Iain Couzin talks with co-host Steven Strogatz about how and why animals exhibit collective behaviors, flocking as a form of biological computation, and some of the hidden fitness advantages of living as part of a self-organized group rather than as an individual. They also discuss how an improved understanding of swarming pests such as locusts could help to protect global food security.

Listen on Apple Podcasts, Spotify, Google Podcasts, TuneIn or your favorite podcasting app, or you can stream it from Quanta.

The team of scientists set about investigating this by analyzing 59 early B-type blue supergiants located in the Large Magellanic Cloud, a satellite galaxy of the Milky Way, and creating novel stellar simulations.

“We simulated the mergers of evolved giant stars with their smaller stellar companions over a wide range of parameters, taking into account the interaction and mixing of the two stars during the merger,” study leader and IAC researcher Athira Menon said in a statement. “The newly born stars live as blue supergiants throughout the second-longest phase of a star’s life, when it burns helium in its core.”

The team’s findings suggest that blue supergiants slip into an evolutionary gap in conventional stellar physics — a phase of stellar evolution where astronomers would not expect to see stars. The question is, Can this explain the remarkable properties of blue supergiant stars? It seems the answer is yes.

Ever wonder where all the active supermassive black holes are in the universe? Now, with the largest quasar catalog yet, you can see the locations of 1.3 million quasars in 3D.

The catalog, Quaia, can be accessed here.

“This quasar catalog is a great example of how productive astronomical projects are,” says David Hogg, study co-author and computational astrophysicist at the Flatiron Institute, in a press release. “Gaia was designed to measure stars in our galaxy, but it also found millions of quasars at the same time, which give us a map of the entire universe.” By mapping and seeing where quasars are across the universe, astrophysicists can learn more about how the universe evolved, insights into how supermassive black holes grow, and even how dark matter clumps together around galaxies. Researchers published the study this week in The Astrophysical Journal.

By analyzing the data from ESA’s XMM-Newton and Gaia satellites, astronomers from the Leibniz Institute for Astrophysics Potsdam (AIP) in Germany and elsewhere have detected a new magnetic cataclysmic variable system, most likely of the polar type. The finding was reported in a research paper published March 21 on the pre-print server arXiv.

Could it be that human existence depends on gravitational waves? Some key elements in our biological makeup may come from astrophysical events that occur because gravitational waves exist, a research team headed by John R. Ellis of Kings College London suggests.