The U.S. Food and Drug Administration (FDA) today approved a controversial Alzheimer’s disease treatment for broad use—with caveats. The drug, an antibody called lecanemab, is the first to clearly slow cognitive decline in patients with early-stage disease, fueling excitement in the Alzheimer’s field and hope for patients and families. But its benefits appear modest, and it...

In the western, volcano-ringed highlands of Guatemala, Willy Barreno Minera keeps watch over the skies. As an ajq’ij , a daykeeper and spiritual guide, the stars and landscape help him keep track of the 260-day calendar that has ruled the life of his Maya K’iche’ community—an Indigenous group of about 1.6 million people—in Quetzaltenango for generations....

The ancient Roman Empire still makes its presence felt throughout Europe. Bathhouses, aqueducts, and seawalls built more than 2000 years ago are still standing—thanks to a special type of concrete that has proved far more durable than its modern counterpart. Now, researchers say they have figured out why Roman concrete remains so resilient: Quicklime used in the mix may have given the...