Delicate butterfly wings are pretty cool — literally, thanks to special structures that protect them from overheating in the sun.
New thermal images of butterflies show that living parts of the wing — including veins transporting insect blood, or hemolymph, and scent patches or pads that males use to release pheromones — release more heat than surrounding dead scales, keeping the living areas cooler.
Small changes in body temperature can affect a butterfly’s ability to fly, as muscles in the thorax must be warm so that the insect can flap its wings fast enough for takeoff. But because the wings are so thin, they heat up faster than the thorax and can rapidly overheat.
People might think that scale-covered butterfly wings are “like a fingernail, or a feather of a bird, or human hair — they are lifeless,” says Nanfang Yu, an applied physicist at Columbia University (SN: 5/23/08). But wings are also equipped with living tissues crucial for survival and flight, and high temperatures will make the insect “really feel uncomfortable.”
The team also discovered some butterflies have a structure that looks like a beating “heart” in their wings. It pumps hemolymph through the scent pads of male hickory hairstreak (Satyrium caryaevorus) and white M hairstreak (Parrhasius m-album) butterflies, and beats a few dozen times per minute.
DNA REFLECTS HISTORY OF MIGRATIONS IN SOUTHEAST ASIA
People who moved out of southern China cultivated big changes across ancient Southeast Asia, a new analysis of ancient human DNA finds.
Chinese rice and millet farmers spread south into a region stretching from Vietnam to Myanmar. There, they mated with local hunter-gatherers in two main pulses, first around 4,000 years ago, and again two millennia later, says a team led by Harvard Medical School geneticist Mark Lipson. Those population movements brought agriculture to the region and triggered the spread of Austroasiatic languages that are still spoken in parts of South and Southeast Asia, the scientists conclude online May 17 in Science.
Over the past 20 years, accumulating archaeological evidence has pointed to the emergence of rice farming in Southeast Asia between 4,500 and 4,000 years ago, accompanied by tools and pottery showing links to southern China. Austroasiatic languages now found from Vietnam to India contain words for rice and agriculture, suggesting that ancient arrivals from southern China spoke an Austroasiatic tongue. Questions have remained, though, about where Austroasiatic languages originated and whether knowledge about farming practices, rather than farmers themselves, spread from China into Southeast Asia.
Now, DNA from ancient Southeast Asians provides “clinching evidence” for the spread of farming via southern Chinese groups, says archaeologist Charles Higham of the University of Otago in Dunedin, New Zealand, who did not participate in the study. The new report aligns with other ancient DNA evidence of culture-changing population movements across parts of Asia starting around 5,000 years ago (SN: 11/25/17, p. 16). “Ancient human DNA is showing that prehistoric people were far more mobile and exploratory than has often been thought,” Higham says.
Lipson’s team obtained DNA from 18 human skeletons unearthed at five Southeast Asian sites dating to between around 4,100 and 1,700 years ago. These sites are located in Vietnam, Myanmar, Thailand and Cambodia.
DNA preserves poorly in such hot, humid regions. A group led by study coauthor Ron Pinhasi, an archaeologist at the University of Vienna, recently found that human DNA survives best in a skull bone surrounding inner-ear structures that has especially dense tissue. In the new study, DNA was extracted from that bone for each ancient individual.
Roughly 4,000-year-old farmers at Vietnam’s Man Bac site displayed a close genetic relationship to present-day speakers of Austroasiatic languages, especially in southern China, Lipson’s group says. About 25 to 30 percent of the Man Bac farmers’ ancestry came from hunter-gatherers, the scientists estimate, perhaps due to interbreeding of rice growers and foragers in southern China before any migrations occurred. Many populations today that speak Austroasiatic languages also display a similar genetic signature. Genetic signs of additional hunter-gatherer ancestry, probably acquired in Southeast Asia, appeared in two of eight Man Bac farmers.
At approximately 2,000-year-old sites in Vietnam and Myanmar, farmers inherited a genetic makeup that differed in some ways from that of the earlier Man Bac crowd, but still closely resembled the DNA of present-day inhabitants of southern China. A second southern Chinese migration into Southeast Asia likely led to those DNA tweaks, the researchers say.
WASHINGTON — Many people have turned to electronic cigarettes in hopes of avoiding the heart and cancer risks associated with smoking conventional tobacco products. But vaping appears far from benign, a trio of toxicologists reported February 11 and 12 at the American Association for the Advancement of Science annual meeting.
If used as a means to totally wean people off of tobacco products, then e-cigarettes might have value, concedes Ilona Jaspers of the University of North Carolina at Chapel Hill. But she’s not sure. Unpublished data that she and the others presented at the meeting link e-cig products to a host of new risks. So vaping may not eliminate risks associated with conventional smoking, Jaspers maintains — “and may actually be introducing new ones.”
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Vaping linked to host of new health risks was originally published on Emergency Broadcast System
Not too long ago, the internet was stationary. Most often, we’d browse the Web from a desktop computer in our living room or office. If we were feeling really adventurous, maybe we’d cart our laptop to a coffee shop. Looking back, those days seem quaint.
Today, the internet moves through our lives with us. We hunt Pokémon as we shuffle down the sidewalk. We text at red lights. We tweet from the bathroom. We sleep with a smartphone within arm’s reach, using the device as both lullaby and alarm clock. Sometimes we put our phones down while we eat, but usually faceup, just in case something important happens.
Our iPhones, Androids and other smartphones have led us to effortlessly adjust our behavior. Portable technology has overhauled our driving habits, our dating styles and even our posture. Despite the occasional headlines claiming that digital technology is rotting our brains, not to mention what it’s doing to our children, we’ve welcomed this alluring life partner with open arms and swiping thumbs.
Scientists suspect that these near-constant interactions with digital technology influence our brains. Small studies are turning up hints that our devices may change how we remember, how we navigate and how we create happiness — or not.
Somewhat limited, occasionally contradictory findings illustrate how science has struggled to pin down this slippery, fast-moving phenomenon. Laboratory studies hint that technology, and its constant interruptions, may change our thinking strategies. Like our husbands and wives, our devices have become “memory partners,” allowing us to dump information there and forget about it — an off-loading that comes with benefits and drawbacks. Navigational strategies may be shifting in the GPS era, a change that might be reflected in how the brain maps its place in the world. Constant interactions with technology may even raise anxiety in certain settings.
Yet one large study that asked people about their digital lives suggests that moderate use of digital technology has no ill effects on mental well-being.
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Smartphones may be changing the way we think was originally published on Emergency Broadcast System
“'We’re entering a really exciting area where we can develop all sorts of very complicated technologies that can actually have biomedical applications and improve the quality of life for people,' says bioengineer Grégoire Courtine of the Swiss Federal Institute of Technology in Lausanne. 'It’s a revolution.'
This was a big year for prosthetic parts, both in and out of the lab. Athletes in London for the Paralympics and the Olympics sprinted on high-tech carbon blades and hurled javelins while balancing on the microprocessor-controlled C-Leg. People in wheelchairs used battery-powered robotic suits to keep their lower limbs in shape. A young man who lost his right leg in a motorcycle accident climbed the 103 flights of stairs in Chicago’s Willis Tower with a thought-controlled limb. That technology is still in development. But some bionic add-ons are starting to come out of the lab and into the clinic for the first time, though costs remain prohibitive for many potential users...
Work by Courtine and colleagues has [also] hinted at a different kind of sci-fi–like future — one with no need for bionics. Their research showed the potential of restoring function to limbs without using prosthetics at all. Rats paralyzed by spinal cord injuries were able to walk, run and even climb stairs after weeks of treatment combining drugs and electric shocks to the spine with physical therapy on treadmills (SN: 6/30/12, p. 5). But it wasn’t just technology that made the feat possible; the research showed the importance of that intangible thing called motivation. The rats who learned to walk were the ones that really wanted it; those trained without a tempting treat never learned to walk."
