by David Braun
Brain Food
Stone tools and the butchered bones of turtles, crocodiles, and fish were found at the 1.95-million-year-old site in northern Kenya. No human bones were found, but the combination of remains suggests early humans used the site specifically to prepare meals.
Fossilized skull of an Euthecodon, a prehistoric crocodile (Photo Credit 2.11)
According to the study authors, the addition of water-based prey into early-human diets may have been what boosted brain size in certain hominins—humans plus human ancestral species and their close evolutionary relatives. That’s because reptiles and fish are particularly rich in long-chain polyunsaturated fatty acids. Some experts think this so-called good fat was “part of the package” of human brain evolution, said study leader David Braun, an archaeologist at the University of Cape Town in South Africa.
Discovering evidence for “brain food” in the late Pliocene (about 3 million to 1.8 million years ago) may explain how bigger brains—for instance in our likely direct ancestor Homo erectus—arose in humans and their relatives about 1.8 million years ago, Braun said.
Exotic Meats
A number of exotic meats are eaten all over the world and in the United States today, including:
1. Bat (Guam, Indonesia)
2. Kangaroo (Australia)
3. Snake (China)
4. Duck embryo (Vietnam and the Philippines)
5. Crocodile and alligator (Thailand, Australia, parts of the U.S.)
6. Yak (Tibet)
Early Humans Not Crocodile Hunters
Remains of about 48 animal species were found at the Kenyan site, once a delta crisscrossed with small rivers. In addition to the aquatic animals, there’s evidence early humans feasted on mammals such as ancient rhinoceroses, hippopotamuses, and antelope, the researchers report in a paper published in the journal Proceedings of the National Academy of Sciences. Some of the animal bones bore cut marks from simple, sharp-edged stone tools, according to the study authors.
But the Kenyan hominins were not crocodile hunters, Braun noted. Instead, early humans likely scavenged carcasses, bringing the meat back to the kitchen area to carve up and—in the pre-fire era of human history—eat raw.
Brain Changes
The idea that a diet of aquatic animals “would have been a healthy one in terms of growth and development seems reasonable,” Dean Falk, an anthropologist at Florida State University in Tallahassee, said by email. But “the old idea that brain size ‘took off’ … around [two million years ago] has lost support in the last decade,” added Falk, who was not involved in Braun’s study.
For instance, a separate study in 2000 led by Falk and published in the Journal of Human Evolution found that parts of the brain in some species of the human-ancestor genus Australopithecus had started to change shape—a trend associated with an increase in brain size—well before two million years ago. Regardless, study leader Braun said, for the Homo genus overall, a diverse menu of mammals and reptiles at some point in human evolution “may be what gave us that adaptive edge.”
TRUTH:
CROCODILES HAVE BEEN AROUND FOR ABOUT 200 MILLION YEARS.
FINGERNAILS IN SPACE
Astronauts’ Fingernails Falling Off
If you’re headed for space, you might rethink that manicure: Astronauts with wider hands are more likely to have their fingernails fall off.
A new study reveals that space suit gloves can lead to fingernail troubles—especially for astronauts with wide hands. In fact, fingernail trauma and other hand injuries—no matter your hand size—are collectively the number-one nuisance for spacewalkers, said study co-author Dava Newman, a professor of aeronautics and astronautics at the Massachusetts Institute of Technology.
Are space gloves causing the problem? (Photo Credit 2.12)
Not Fitting Like a Glove
“The glove in general is just absolutely one of the main engineering challenges,” Newman said. “After all, you have almost as many degrees of freedom in your hand as in the rest of your whole body.”
TRUTH:
YOUR FINGERNAILS TAKE SIX MONTHS TO GROW FROM BASE TO TIP.
The trouble is that the gloves, like the entire space suit, need to simulate the pressure of Earth’s atmosphere in the chilly, airless environment of space. The rigid, balloonlike nature of gas-pressurized gloves makes fine motor control a challenge during extravehicular activities (EVAs), aka spacewalks.
A previous study of astronaut injuries sustained during spacewalks had found that about 47 percent of 352 reported symptoms between 2002 and 2004 were hand related. More than half of these hand injuries were due to fingertips and nails making contact with the hard “thimbles” inside the glove fingertips.
In several cases, sustained pressure on the fingertips during EVAs caused intense pain and led to the astronauts’ nails detaching from their nail beds, a condition called fingernail delamination.
While this condition doesn’t prevent astronauts from getting their work done, it can become a nuisance if the loose nails are snagged inside the glove. Also, moisture inside the glove can lead to secondary bacterial or yeast infections in the exposed nail beds, the study authors say. If the nail falls off completely, it will eventually grow back, although it might be deformed.
For now, the only solutions are to apply protective dressings, keep nails trimmed short—or do some extreme preventative maintenance. “I have heard of a couple people who’ve removed their fingernails in advance of an EVA,” Newman said.
Pushing Through the Pain
In the current glove design, astronauts wear a pressurized inner layer under a thick outer layer that offers protection from the cold and any passing micrometeorites. On Earth, wearing such space suit gloves might feel like donning a thick set of gardening gloves—a bit restrictive but not too uncomfortable.
“When the glove pressurizes, that nice, flexible fabric surface becomes stiff, like putting air into bicycle tires,” said Peter Homer, founder of commercial space suit design company Flagsuit LLC in Maine and two-time winner of NASA’s Astronaut Glove Challenge.
“What you find is, depending on the design of the glove, there’s pressure on the hard points the hand presses against, and that can give you blisters or cuts,” said Homer, who was not involved in the new study. “Also, the materials tend to be rubberized to make the gloves airtight, but that creates a lot of friction against the skin, and that can again create blisters.”
During EVAs, astronauts have to work in these gloves for six to eight hours at a stretch. Homer said: “It amazes me that astronauts push through all that pain and get stuff done.”
Long Fingers vs. Big Hands
To help design more comfy space suit gloves, MIT’s Newman and colleagues initially tested whether fingernail trauma is related to the length of astronauts’ fingers. The team first collected data from the Injury Tracking System, a database of astronaut medical logs at NASA’s Johnson Space Center in Houston, Texas. Of the 232 crew members with complete injury records and body measurements, 22 reported at least one case of fingernail delamination.
Space Suit Components
How complicated could a space suit be? The answer is very. Officially called the Extravehicular Mobility Unit, or EMU, NASA’s space suit is like a personal mini-spacecraft. Here are the different parts that make up an EMU:
1. Primary Life Support Subsystem (PLSS)
2. Upper Torso
3. Hard Upper Torso (HUT)
4. Arms
5. Extravehicular activity (EVA) Gloves
6. Displays and Control Module
7. In-Suit Drink Bag
8. Lower Torso Assembly
9. Helmet
10. Communications Carrier Assembly (CCA)
11. Liquid Cooling and Ventilation Garment
12. Maximum Absorption Garment
13. Simplified Aid for EVA Rescue
14. Wrist Mirror
15. Layers
16. Cuff Checklist
17
. Safety Tethers
Surprisingly, an analysis of hand measurements among injured astronauts and a noninjured control group showed no statistical relationship between finger length and the instances of nails falling off, according to the study.
Instead, the team found that fingernail trauma was a bigger problem for people with a wider hand circumference, as measured around the metacarpophalangeal, or metacarpal, joint, where the fingers meet the palm.
“If you take a pencil and grip it, you’re using your metacarpal joint,” Newman said. “That’s a really difficult thing to repeat when you have a pressurized glove on. A hard palm bar in the soft fabric glove … helps make that crease,” but the bar also puts pressure on the joint.
The team’s analysis, to be published in the journal Aviation, Space, and Environmental Medicine, showed that astronauts with hand circumferences greater than about 9 inches (22.8 centimeters)—what Newman called the “large to extra-large range”—had a 19.6 percent chance of fingernail injuries during an EVA. By contrast, astronauts with smaller hand circumferences had just a 5.6 percent chance of losing their nails on the job.
Cold Hands, Hurt
“What surprised me is that [the] conventional wisdom [says] that fingernail problems are caused by repetitive tapping on the fingernail … and you’d think that if you had longer fingers, you’d be banging on the end of the glove more,” said Flagsuit’s Homer.
But the hand-width hypothesis “is good, too,” he said. “The bigger the hand is, the more the glove squeezes on [the metacarpophalangeal] joint and cuts off blood flow.”
Space Headaches?
A recent survey found that astronauts who did not normally have severe headaches on Earth reported experiencing “exploding” or “heavy-feeling” headaches during spaceflights and extended stays aboard the International Space Station. Although no definitive cause has been determined, there are a few reasons that are likely: “puffy face syndrome,” in which fluids that are usually found in the lower extremities shift to other parts of the body; poor air circulation; and perhaps just the same reasons people get them on Earth.
Damage to the tissue underneath the fingernail could also occur if circulation at the knuckle joint is repeatedly shut off and then restored, which could also lead to delamination. This could also explain why so many astronauts have reported that their fingertips get cold during EVAs despite their thermal gloves, Homer said. Overall, he added, the new paper “shines light on a whole new direction on how to address this issue.” According to Homer, the key is to make all parts of a glove custom fitted for each astronaut.
A Custom Fit
For anyone selected for an EVA, the airtight inner layer for the current glove design is custom made via hand casts, laser scanning, computer modeling, and special machining techniques. But the outer layer is built in discrete sizes—more like a “small, medium, large” situation, he said.
“It costs around a hundred thousand dollars up front to custom fit the airtight bladder,” Homer said. “In my opinion that also needs to apply to the outer layer, which really gives the glove its shape.”
Customization may not always solve the issue, though, MIT’s Newman said: “Some may like a tighter or looser fit—there’s variability in subjective desires. And if you have a really tight fit, you’re going to have a lot more pressure” on the metacarpal joint.
Robots and Shrink Wrap?
Newman thinks another option worth looking into is robotic amplification inside the glove. “Say I’m grabbing on to something. I’m using muscles to act against gas-pressurized gloves,” she said. “But what if I had little actuators in there? My fingers can do less work—that’d be great!”
She added that “there are design trade-offs” to robotic gloves. “But we have some big dreams here: small-mass systems close to the skin that work in concert with muscles and bones, not big clunky exoskeletons.”
Newman and colleagues have also been experimenting with entire skintight space suits that rely on mechanical counterpressure: Rather than working in a gas-pressurized bubble, astronauts would effectively get shrink-wrapped in a suit made of flexible material.
No matter what the approach, Newman said, “the bottom line is we want people to be working in a space suit glove that’s working with them, not against them.”
TRUTH:
ASTRONAUTS GROW UP TO THREE INCHES TALLER IN OUTER SPACE.
BALL IN YOUR HEAD
Ball Lightning
May Be a Hallucination
Mysterious floating blobs of light known as ball lightning might simply be hallucinations caused by overstimulated brains, a new study suggests.
For hundreds of years eyewitnesses have reported brief encounters with golf ball—to tennis ball—size orbs of electricity. But scientists have been unable to agree on how and why ball lightning forms, since the phenomenon is rare and very short-lived.
Ball Lightning Basics
Eyewitnesses have described ball lightning as a floating, glowing ball similar in size to a tennis ball or even a beach ball. The sightings generally accompany thunderstorms, but it’s unclear what other similarities ball lightning might share with its conventional relative.
Ball lightning floats near the ground, sometimes bounces off the ground or other objects, and does not obey the whims of wind or the laws of gravity. An average ball lightning glows with the power of a 100-watt bulb. Some have been reported to melt through glass windows and burn through screens. The phenomenon lasts only a short time, perhaps ten seconds, before either fading away or violently dissipating with a small explosion.
TRUTH:
THERE ARE ABOUT 3,000 LIGHTNING FLASHES ON EARTH EVERY MINUTE.
The record suggests that ball lightning is not inherently deadly, but there are reports of people being killed by contact—most notably the pioneering electricity researcher Georg Richmann, who died in 1753. Richmann is believed to have been electrocuted by ball lightning as he conducted a lightning-rod experiment in St. Petersburg, Russia.
In the Mind’s Eye?
Because ball lightning is often reported during thunderstorms and it’s known that multiple consecutive lightning strikes can create strong magnetic fields, Joseph Peer and Alexander Kendl at the University of Innsbruck in Austria wondered whether ball lightning is really a hallucination induced by magnetic stimulation of the brain’s visual cortex or the eye’s retina.
In previous experiments, other scientists had exposed humans to strong, rapidly changing magnetic fields using a medical machine called a transcranial magnetic stimulator, or TMS. The machine’s magnetic fields are powerful enough to induce electric currents in human brain cells without being harmful.
Focusing magnetic fields on the visual cortex of the brain caused the subjects to see luminous discs and lines. When the focus was moved around within the visual cortex, the subjects reported seeing the lights move.
In their paper, which appeared on the physics research website arXiv.org, Peer and Kendl argue that magnetic fields made by lightning could have the same effect as TMS machines on nearby humans. In fact, the pair thinks about half of all ball lightning reports are actually tricks of the mind induced by magnetism.
A 19th-century illustration of ball lightning (Photo Credit 2.13)
Not All Imaginary
The researchers make a convincing argument that some ball lightning reports are spurred by hallucinations, said John Abrahamson, a chemist and ball lightning expert at the University of Canterbury in New Zealand who was not involved in the study.
But “I cannot believe that most of the images reported as ball lightning are due to this brain influence,” Abrahamson said in an email. For one thing, the colors of light seen by the subjects in the experiment were “white, gray, or in unsaturated colors.” But ball lightning has been reported in a variety of colors, including orange, green, and blue, Abrahamson said.
Also, some eyewitness reports of ball lightning include close-up observations detailing the internal structu
res of the balls and even associated smells and sounds. Some reports of ball lightning even involve multiple eyewitnesses who saw the same phenomenon from different angles and saw the balls travel in the same directions.
TRUTH:
THE AIR AROUND A LIGHTNING STRIKE IS FIVE TIMES HOTTER THAN THE SUN.
“This common geometric perception from different angles would be very unlikely if their brains were being stimulated” by the local magnetic field caused by lightning strikes, Abrahamson said.
Lighting Up the Lab
Eli Jerby, an engineer at Tel Aviv University in Israel, has actually created something similar to ball lightning in the lab. He also doesn’t think hallucinations could account for all ball lightning reports. “While hallucinations could explain some cases, the effect of ball lightning is yet feasible in both nature and the laboratory,” Jerby said in an email.
“Furthermore, with the recent experimental progress by us and by others, we are closer than ever to simulating natural ball lightning completely in the lab, and to explaining the real ball lightning enigma” in nature.
TASTING WORDS, HEARING COLORS
Secrets of Synesthesia
Neural tangling called synesthesia may have creative benefits, experts say.
A neural condition that tangles the senses so that people hear colors and taste words could yield important clues to understanding how the brain is organized, according to a new review study.