Plus: China is catching up with America's AI lead Climate change is subjecting vulnerable people to temperatures that push their limits. In 2023, about 47,000 heat-related deaths are believed to have occurred in Europe. Researchers estimate that climate change could add an extra 2.3 million European heat deaths this century. That's heightened the stakes for solving the mystery of just what happens to bodies in extreme conditions. While we broadly know how people thermoregulate, the science of keeping warm or cool is mottled with blind spots. Researchers around the world are revising rules about when extremes veer from uncomfortable to deadly.

Scientists hope to prevent deaths from climate change, but heat and cold are more complicated than we thought. Libby Cowgill is an anthropologist at the University of Missouri who hopes to revamp the science of thermoregulation. Libby Cowgill, an anthropologist in a furry parka, has wheeled me and my cot into a metal-walled room set to 40 F. A loud fan pummels me from above and siphons the dregs of my body heat through the cot's mesh from below. A large respirator fits snug over my nose and mouth. The device tracks carbon dioxide in my exhales--a proxy for how my metabolism speeds up or slows down throughout the experiment. Eventually Cowgill will remove my respirator to slip a wire-thin metal temperature probe several pointy inches into my nose. Cowgill and a graduate student quietly observe me from the corner of their so-called "climate chamber. Just a few hours earlier I'd sat beside them to observe as another volunteer, a 24-year-old personal trainer, endured the cold. Every few minutes, they measured his skin temperature with a thermal camera, his core temperature with a wireless pill, and his blood pressure and other metrics that hinted at how his body handles extreme cold. He lasted almost an hour without shivering; when my turn comes, I shiver aggressively on the cot for nearly an hour straight. I'm visiting Texas to learn about this experiment on how different bodies respond to extreme climates. I jokingly ask Cowgill as she tapes biosensing devices to my chest and legs. After I exit the cold, she surprises me: "You, believe it or not, were not the worst person we've ever seen." Climate change forces us to reckon with the knotty science of how our bodies interact with the environment. Cowgill is a 40-something anthropologist at the University of Missouri who powerlifts and teaches CrossFit in her spare time. She's small and strong, with dark bangs and geometric tattoos. Since 2022, she's spent the summers at the University of North Texas Health Science Center tending to these uncomfortable experiments. Her team hopes to revamp the science of thermoregulation. While we know in broad strokes how people thermoregulate, the science of keeping warm or cool is mottled with blind spots. "We have the general picture.

The prediction of extreme greenhouse temperatures to which crops are susceptible is essential in the field of greenhouse planting. It can help avoid heat or freezing damage and economic losses. Therefore, it's important to develop models that can predict them accurately. Due to the lack of extreme temperature data in datasets, it is challenging for models to accurately predict it. In this paper, we propose an improved loss function, which is suitable for a variety of machine learning models. By increasing the weight of extreme temperature samples and reducing the possibility of misjudging extreme temperature as normal, the proposed loss function can enhance the prediction results in extreme situations. To verify the effectiveness of the proposed method, we implement the improved loss function in LightGBM, long short-term memory, and artificial neural network and conduct experiments on a real-world greenhouse dataset. The results show that the performance of models with the improved loss function is enhanced compared to the original models in extreme cases. The improved models can be used to guarantee the timely judgment of extreme temperatures in agricultural greenhouses, thereby preventing unnecessary losses caused by incorrect predictions.

The lightest material on Earth now packs a powerful punch. Scientists from Texas and around the world have created a material that, by density, is lighter than air yet, when electrified, instantly and powerfully contracts. Their work is detailed in this week's issue of the journal Science. "These artificial muscles are very lightweight and can do wonderful things," said Ray Baughman, the study author from the University of Texas at Dallas. While the artificial muscle is unlikely to be used in humans or prosthetic limbs, Baughman says "these sheets of carbon nanotubes ... are of great practical interest for LEDs, solar cells, and other applications."