Mar 29, 2025 Dispatch

Edition 30 – Moons, Pi, Noise, and more

The big stories

Scientists discovered that epithelial cells, which line our skin and organs and were previously thought to be passive barriers, can actually generate and transmit electrical signals when injured. These bioelectric signals can travel across distances more than 40 times the cells' length, with voltages similar to neurons but about 1,000 times slower, helping coordinate wound healing responses. Research showed that calcium ions play a crucial role in generating these signals, and removing them with EDTA or blocking ion channels reduced or eliminated the electrical activity. This discovery opens exciting possibilities for improved wound treatment through targeted electrical stimulation, potentially leading to more effective healing therapies than current methods that use much higher frequencies on entire tissue areas.

The fascinating journey of calculating pi spans over 4000 years, from Mādhava's infinite series to Archimedes' polygon technique. The quest for more digits accelerated dramatically with computing technology, evolving from Shanks' manual calculation of 527 digits in 1873 to the recent record of 202 trillion decimal places achieved over 85 days using massive computing power. Despite these incredible achievements in calculation, pi remains eternally elusive as an irrational and transcendental number, though practically speaking, just 37 decimal places are sufficient to measure the observable universe's circumference to the width of a hydrogen atom.

Optical illusions, like the famous Ebbinghaus circles where identical circles appear different sizes, reveal fascinating insights about how our brains process visual information through context. Susceptibility to these illusions varies significantly based on factors including gender, age, neurodevelopmental conditions, and cultural background – with East Asian observers typically experiencing stronger effects than Western viewers, and the nomadic Himba tribe showing almost no effect at all. A groundbreaking study of 44 radiologists revealed that their extensive medical imaging training enables them to see through these illusions much better than psychology and medical students, challenging previous beliefs that illusion perception couldn't be changed through training. While it takes years of specialized medical training to develop this skill, this discovery opens new possibilities for understanding how expertise in one field can unexpectedly enhance cognitive abilities in another.

French train passenger fined €150 for using phone on speaker

A passenger on the French rail network SNCF has revealed that he received a €150 fine for using his phone on loud speaker within a train station.

The Local FranceEmma Pearson

A French train passenger faced a €150 fine, increased to €200, for using his phone on speaker while waiting at Nantes station, highlighting SNCF's strict policies on noise disturbance. While specific rules about loudspeaker phone use aren't explicitly listed, French transport code prohibits unauthorized sound devices that disturb others, and SNCF train passengers are typically expected to use silent mode or make calls in designated areas. Train conductors have discretionary power to fine passengers for disruptive behavior, though such strict enforcement at train stations is unusual compared to more lenient practices on city transport like the Paris Metro. The situation illuminates France's broader commitment to maintaining peaceful public spaces, though the passenger plans to legally contest the fine's validity.