Science

The sand dike exposure and research team in the Ganges floodplain of Bangladesh. Photo: Liz Chamberlain Liz Chamberlain and Steve Goodbred, two sedimentologists from Vanderbilt University, were traipsing around coastal Bangladesh in March 2018 when they saw the sand dikes. Chamberlain and Goodbred had come to Bangladesh to investigate how fast rivers meander, or shift, in the coastal part of the Ganges-Brahmaputra Delta. Their research team, also consisting of Goodbred’s graduate student Rachel Bain, and Abdullah Al Nahian and Mahfuzur Rahman from Dhaka University, was taking sediment samples from loops in the many rivers that cross the lower delta plain. They would use these samples to date the sediments left behind as the rivers shifted. Midway through the trip, they came acros...

An analysis of millions of tweets reveals the changing meaning of the word “bot”Svet foto/Shutterstock Calling someone a bot on social media once meant you suspected they were actually a piece of software, but now the use of the word is shifting to become an insult to someone you know is human, say researchers. Many efforts to detect social media bots use algorithms to try to identify patterns of behaviour that are more common in automated accounts controlled by computers, the traditional meaning of a bot, but their accuracy is questionable. “Most recent research really focuses on the detection of social bots, which is problematic in itself because we have this ground truth problem,” says Dennis Assenmacher at Leibniz Institute for Social Sciences in Cologne, Germany, ...

Hitting certain crystals with lasers makes them produce quantum lightJaka Korenjak Creating quantum light just became easier thanks to liquid crystals like the ones found in television screens. Light with quantum properties is crucial for many future technologies. Entangled particles within such light could help produce quantum communications networks to support an unhackable internet or quantum imaging techniques for biomedicine. Matjaž Humar at Jožef Stefan Institute in Slovenia says that despite these advanced applications, the methods for making quantum light have barely changed for six decades – until now. He and his colleagues devised a way to create it with liquid crystals. Team member Vitaliy Sultanov at the Max Planck Institute in Germany says traditional...

New Scientist‘s Graham Lawton recently visited two construction sites in Paris that showcase the wonder material of the future: wood. Each site uses wood as an alternative to typical modern construction materials such as steel and concrete, and the potential benefits are numerous: from lower carbon emissions to improved mental health. Wooden construction, it would seem, could help restore our health and the planet’s. At Marcadet Belvédère, a former parcel terminus for the French railway network overlooked by the Basilica of the Sacred Heart, property developer WO2 is adding five extra storeys to the existing concrete shell to create new office space. The new storeys are mostly made of cross-laminated timber (CLT), an engine...

For an experiment designed to reverse time, the apparatus was surprisingly simple: little more than a tank of water. With a puff of air to disturb the surface, Emmanuel Fort created a set of ripples moving outwards in concentric circles. Then, as the waves spread, he gave the tank a practised jolt – at which point they suddenly started travelling inward, refocusing at the point of origin. Fort’s work in 2016 was the first of what has become a deluge of experiments in which waves are manipulated, controlled and even reversed with unprecedented precision. And these days, we are no longer just playing with water. Researchers have figured out how to create a range of “temporal metamaterials” that can manipulate and rewind electromagnetic waves, including visible light its...