Top stories: A scientific gender gap, Roman toilets, and fighting migraines

(LEFT TO RIGHT): XING LIDA AND YUJIANG HAN; PRISMA ARCHIVO/ALAMY; ILLUSTRATION: DAVID BONAZZI/BONAZZI/@SALZMANART

Top stories: A scientific gender gap, Roman toilets, and fighting migraines

Four new elements complete the seventh row of the periodic table

That periodic table poster on your wall is about to be out of date, thanks to four new chemical elements that just received official recognition. The newcomers are some of the heaviest ever discovered, with atomic numbers of 113, 115, 117, and 118. They will be named by the researchers who identified them, the final step before the elements take up their rightful places in the seventh row of the periodic table.

Female engineers publish in better journals, but receive fewer citations

Nearly everyone agrees that science has a gender problem. But the size of the gap depends on the area of science. Now, a study of nearly 1 million engineering paper co-authorships puts hard numbers on the problem in this male-dominated scientific field, and finds a paradoxical trend: Female engineers are publishing in slightly more prestigious journals on average than their male colleagues, but their work is getting less attention.

A shot at migraine

Free this week! Millions dread the onset of migraine headaches, which strike roughly 12% of the world’s population at least once per year. Existing treatments can only head off migraines after they start, and don’t work for many people. On the horizon, however, is a new class of drugs that many scientists believe can stop migraines at their root.

Roman toilets may actually have been bad for public health

At its zenith, the Roman Empire spanned three continents, encircled the Mediterranean, and was home to one-fifth of the planet’s population. The Romans brought roads, bridges, and, perhaps most importantly, sanitation. But a new study of ancient feces casts doubt on just how effective the Roman sanitation system was at improving public health.

Rogue dwarf galaxy left ripples in Milky Way

A decade ago, astronomers discovered that the gas in our Milky Way galaxy is not spread out into a completely flat disk, but has ripples, launching a search for the disturbances that caused them. Now, researchers in the nascent field of galactic seismology have found a possible cause of at least some of those ripples: a dwarf galaxy that shot like a bullet through the galactic disk some half-a-billion years ago.

The Iceman had a tummy bug

On the day that Ötzi the “Iceman” was murdered in the Tyrolean Alps of Italy about 5300 years ago, he had a full stomach—and a tummy bug. But it wasn’t just any gut microbe—this early farmer was infected with a particular ancient strain of Helicobacter pylori bacteria that is most similar to modern Asian strains. By sequencing the genome of this ancient pathogen, which can cause ulcers in people today, researchers have made a surprising discovery about Ötzi’s own history.

Dinosaurs may have danced like birds to woo mates

Did meat-eating dinosaurs like Tyrannosaurus rex do a chicken dance to woo their mates? That’s the implication of a new study, which points to fossilized foot scrapes as evidence that a variety of dinosaurs pranced like parrots and puffins to impress the opposite sex. The finding adds further evidence that ancient dinos shared many of the same behaviors as their modern bird relatives.

‘Personhood’ chimpanzees retuned to owners, ending animal rights litigation

Two New York research chimpanzees have been returned to the organization that owns them, effectively ending a 2-year legal battle to have the animals declared legal persons. The State University of New York at Stony Brook transferred the animals—Hercules and Leo—back to the New Iberia Research Center in Louisiana in early December, but the animal rights group behind the legal effort has vowed to keep fighting to release them from captivity.