life in the big, interdependent city

¡Hola, mis amigos de la ciencia! This week, researchers reported that hominins strode bipedally across Europe 500,000 years earlier than previously known. By making digital endocasts of bird skulls, researchers in Australia and Canada report an extremely tight match between actual birds’ brains and the digital reconstructions, making brain studies of rare and extinct species possible. And the SMART tokamak facility, a state-of-the-art fusion power generator, successfully generated its first plasma.

Additionally, Europe’s solar deployment has exploded beyond all expectations, mitochondria have a side gig, and city resiliency to extreme events relies on deeper interdependencies than most recumbent-bike-riding urban studies scholars previously realized.

Solar abundant

In 2024, solar power outpaced coal in Europe for the first time, as fossil-fuel power dropped to what a new report describes as “a historic low.” The climate think tank Ember published the report, “European Electricity Review 2025,” this month, finding that solar and wind sources raised the share of renewables in Europe to 47%, compared to 34% in 2019. Fossil fuels over that span fell from 39% to 29%.

Chris Rosslowe, lead author of the report, said, “At the start of the European Green Deal in 2019, few thought the EU’s energy transition would be where it is today: wind and solar are relegating coal to the margins and pushing gas into decline.”

Across Europe, solar capacity is sometimes so abundant at midday that it outpaces demand, resulting in negative or zero price hours. The report recommends deploying battery storage at solar plants to give power producers more control over prices to avoid negative price hours. Currently, battery capacity is concentrated in only a few countries; the report found 70% of existing batteries were in Germany and Italy at the end of 2023.

Organelle versatile

Researchers at Northwestern University found that mitochondria—famous among science writers as “the powerhouse of the cell” to the extent that Microsoft Copilot autosuggests the phrase “mitochondria, the powerhouse of the cell” as soon as writers type “mito”—have another key cellular function never previously reported. In addition to generating sweet ATP for hungry cells, mitochondria play a role in regulating inflammatory immune responses.

To produce ATP (adenosine triphosphate if you’re nasty), electrons traverse the mitochondrial electron transport chain between the mitochondrial outer membrane and the intermembrane space. The electron transport chain (ETC) also controls macrophages, the specialized Navy SEALs of the immune system, a phrase that Copilot could autosuggest if enough science writers get on board.

Among their functions, macrophages release the anti-inflammatory protein IL-10. The researchers wanted to know how the ETC controls this function. They found that mice with a defective mitochondrial complex struggled to recover from infection and inflammation because their cells did not release enough IL-10. Activating a specific reactive oxygen species (ROS) pathway restored IL-10 release.

“This finding highlights a previously unknown connection between mitochondrial activity, inflammation control and the signaling pathways that regulate it,” says Navdeep Chandel, leader of the lab that made the finding.

Interdependencies evaluated

Nobody has a harder job than a post-pandemic manager of a Pret a Manger restaurant in midtown Manhattan. High-end fast food establishments in business districts were hit hard by the COVID shutdowns; many went out of business and those that remain are struggling as work-from-home employment showed enduring popularity. This demonstrates the intuitive dependencies between proximal businesses. Now, a multi-institutional research collaboration reports that there are also deep dependencies between distant businesses driven by the habits of shared customers.

They analyzed an anonymized dataset of GPS locations for a large pool of individuals in major U.S. cities over several years, including New York, Boston, Los Angeles, Seattle and Dallas. They were able to link distant businesses based on multiple same-day visits and simulate disruptions like COVID to analyze cascading impacts.

Takahiro Yabe, professor at NYU Tandon School of Engineering, said, “One of the most striking findings of our study is the presence of large-distance dependencies among certain businesses and amenities. For example, places like offices, colleges and major shopping centers are not only central to their immediate surroundings, but also influence distant businesses like museums, gas stations or restaurants through complex visitation patterns.”

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