Four-minute workouts help after 65, and a buried crater gets its asteroid

Some said an asteroid or comet made it. Others blamed moving underground salt, or a volcanic collapse of the seabed. In 2009 they voted on it, which shows how stuck things were. Dr. Uisdean Nicholson of Heriot-Watt University and his team have now combined seismic imaging, microscopic study of rock samples and computer simulations, and report minerals that form only under extraordinary pressure 2. Their reconstruction: a 160-meter-wide asteroid hit 43 to 46 million years ago, threw a curtain of rock and water 1.5 kilometers into the air, and sent a tsunami more than 100 meters (330 feet) high across the water. The work appeared in Nature Communications 2.

Lead author Christopher Sciamanna, a professor of medicine and public health, put it this way: "The human body is designed to improve very quickly" 3. The setup matters because fewer than one in five older adults meet the recommendation of muscle-strengthening at least twice a week. The usual obstacles are discomfort, lack of time, and the sheer confusion of planning a workout when you have never done one 3.

The cause has been known for decades: loss of the maternal UBE3A gene. What was missing was the route from that one gene to those symptoms, a hard gap to close because UBE3A's protein touches at least 60 biochemical pathways 101. A Washington University School of Medicine team led by Jason Yi, publishing in Nature, found that without UBE3A an ordinarily benign enzyme, asparagine synthetase, piles up. The pile-up makes developing neurons sense starvation that is not there, and they cut protein synthesis to save resources 101. In mouse models, blocking that enzyme, either genetically or with a drug, restored protein synthesis, normalized brain growth and reversed behavioral deficits 101.

Elk, bears, coyotes and others need to cross the highway to reach 39,000 acres of habitat 274. The Colorado Department of Transportation built the largest wildlife-only bridge in North America over the six lanes, covered it in grass so animals never leave soil underfoot, and opened it that month. In its first nine months, wildlife-vehicle collisions were down 91 percent 274. Wildlife biologist Brandon Marette told CBS News that one of his most heartwarming moments was a photo from CDOT of an elk mother taking her calf under I-25, a reminder that the state is also building underpasses and smaller bridges 274.

The roughly 5-ton spacecraft should reach Mars by late summer 2027 and attempt a landing on Phobos, the larger moon at about 22 kilometers across 231. A microwave-sized, four-wheeled French-German rover named Idefix, after the white dog in the Asterix comics, goes first, creeping across the surface at millimeters per second to find a safe spot 231. The lander is meant to spend about two hours on the surface and vacuum up at least 10 grams of material. The probe leaves Mars in 2030, and a sample capsule is due in the Australian desert in 2031 231.

At Northwestern University, Gerald Gabrielse and Tom Myers used a cryogenic, superconducting vacuum trap to keep a single positron for months 87. The hard part is the front end. A radioactive sodium isotope fires positrons out at up to about 546 kiloelectronvolts, around 88 percent of light speed, and the team had to slow them by passing them through matter, a single tungsten crystal, without losing them 87. In Gabrielse's words: "Most of the positrons that emerge from the source are not successfully slowed and captured. They end up 'annihilating' with an electron in our apparatus" 87.

It traces their origins to Easter Island, some 4,400 miles away, along a route that ran from Fiji and Tonga to the Cook Islands, Tahiti and Mangareva, with Easter Island settled in the early 1200s 276. Each hop was a small founding group, and the genetic bottlenecks stacked. In Eastern Polynesians the founder effects are more than ten times larger than in the European-descended populations researchers have studied most, such as Finnish and Amish people 276. "By the time you've gotten all the way to Hawaii, you're at the end of a series of founder effects, so it's really intense," Ioannidis said 276.