Archivo: Science

North America’s birds are disappearing from the skies at a rate that’s shocking even to ornithologists. Since the 1970s, the continent has lost 3 billion birds, nearly 30% of the total, and even common birds such as sparrows and blackbirds are in decline, U.S. and Canadian researchers report this week online in Science. «It’s staggering,» says first author Ken Rosenberg, a conservation scientist at the Cornell University Laboratory of Ornithology. The findings raise fears that some familiar species could go the way of the passenger pigeon, a species once so abundant that its extinction in the early 1900s seemed unthinkable.

Physicists have set a new limit on the mass of nature’s lightest particle of matter. The neutrino can weigh no more than 1.1 electron volts (eV)—less than one-500,000th the mass of an electron—say experimenters with the Karlsruhe Tritium Neutrino (KATRIN) experiment at the Karlsruhe Institute of Technology in Germany. Reported on 13 September at a meeting in Toyama, Japan, the new result halves the previous limit of 2 eV.

Solar panels are great for powering devices during the day. But they don’t work after the sun goes down. Now, a new technology that takes advantage of the cold darkness of space may do the trick.

Forget the legendary lost continent of Atlantis. Geologists have reconstructed, time slice by time slice, a nearly quarter-of-a-billion-year-long history of a vanished landmass that now lies submerged, not beneath an ocean somewhere, but largely below southern Europe.

In the thousands of years we’ve lived with dogs, we’ve transformed them from fearsome wolves to fluffy, tail-wagging Frisbee catchers that range in size from tiny pomeranians to towering great Danes. Now, a new study of dogs’ brain scans suggests our impact on our canine pals has been even more profound: We’ve changed the very structure of their brains.

When we think of how humans have altered the planet, greenhouse gas warming, industrial pollution, and nuclear fallout usually spring to mind. But now, a new study invites us to think much further back in time. Humans have been altering landscapes planetwide for thousands of years: since at least 1000 B.C.E., by which time people in regions across the globe had abandoned foraging in favor of continually producing crops.

If Gao Caixia were a farmer, she might be spread a little thin. Down the hall from her office at a branch of the Chinese Academy of Sciences (CAS) here in Beijing, seeds from a strain of unusually soft rice and a variety of wheat with especially fat grains and resistance to a common fungus sprout in a tissue culture room. A short stroll away, wild tomato plants far hardier than domestic varieties but bearing the same sweet fruit crowd a greenhouse, along with herbicide-resistant corn and potatoes that are slow to brown when cut. In other lab rooms Gao grows new varieties of lettuce, bananas, ryegrass, and strawberries.

In the past 2000 years, Earth has drifted in and out of extended periods of warmer- and cooler-than-normal climate, including the so-called Medieval Warm Period and the Little Ice Age. Scientists long thought that during these hot and cold spells, temperatures rose and fell in sync across the globe. In fact, Earth warmed and cooled unevenly, with different regions reaching peak high and low temperatures at different times, two new studies suggest. The one exception: Since the mid–19th century, warming trends have covered some 98% of the globe.

Dark matter, the mysterious substance that makes up most of the mass of the universe, has proved notoriously hard to detect. But scientists have now proposed a surprising new sensor: human flesh.

Looking a squid in the eye is eerily like looking in a mirror. Squids, octopuses, and other cephalopods are on a very different part of the tree of life from vertebrates. But both have evolved sophisticated peepers that rely on a lens to focus light and provide excellent vision. This independent evolution of such complexity has puzzled biologists for centuries and has prompted searches for clues about how this might have come about.