A shark-eat-shark world.  I’m Bob Hirshon and this is Science Update.

Sand tiger sharks have a very unusual reproductive strategy. For starters, females  have not one uterus, but two. What’s more, the biggest embryo in each uterus gobbles up all of its unborn siblings as it grows. So each uterus produces a single pup, resulting in a litter of two. In a new twist, researchers have discovered that the two surviving pups are almost always sired by the same father, even though the females mate with a number of different males. Stony Brook University marine biologist Demian Chapman led the study.

DEMIAN CHAPMAN (Stony Brook University):

The earliest eggs that are fertilized have the highest probability of reaching that size where the embryo becomes a cannibal. So we think that males that are able to mate first, those are the ones who are going to be most successful.

HIRSHON:

He says in captivity, males have been observed guarding females, perhaps so they can be the first, those are the ones to fertilize the eggs. I’m Bob Hirshon, for AAAS, the science society.

A sand tiger shark at the Newport Aquarium. (Jeff Kubina/Flickr)

Charging up math skills. I’m Bob Hirshon and this is Science Update.

Stimulating a part of the brain involved in math reasoning with a particular electrical current can jumpstart math learning, according to new research published in the journal Current Biology. University of Oxford experimental psychologist Roi Cohen Kadosh led the study.

ROI COHEN KADOSH (University of Oxford):

The technique involves two electrodes and we put them on the area that we want to stimulate, and we deliver a very low current of electricity.

HIRSHON:

Volunteers who completed daily, 20-minute math sessions for five days while receiving the stimulation, out-performed a matched group that did the math without the electrical stimulation. Six months later, they had retained their gains, and even showed improvements visible in brain scans. While the work is basic research, Cohen Kadosh says that down the road, he could imagine the technique going beyond mathematics into other domains, and potentially helping people with learning disabilities. I’m Bob Hirshon, for AAAS, the science society. 

Red and blue electrodes and near infrared spectroscopy to record haemodynamic changes. (Roi Cohen Kadosh)

Scientists fight tanning. I’m Bob Hirshon and this is Science Update.

Indoor tanning can make a young adult 60 to 80 percent more likely to develop deadly melanoma. Yet it remains alarmingly popular. In fact, according to behavioral scientist Dawn Holman of the Centers for Disease Control, about one in three white high school girls today is an indoor tanner.

DAWN HOLMAN (Centers for Disease Control):

And we see similar numbers among young adult women between the ages of 18 to 25. We’ve also noticed that those who indoor tan tend to do so frequently, with over half of indoor tanners reporting that they have 10 or more tanning sessions per year.

HIRSHON:
She adds that state and local regulations, like minimum ages, maximum visits, and required protections, are inconsistent and poorly enforced. While fixing that would help, she emphasizes that everyone needs to understand the dangers of indoor tanning, and explain them to their kids. I’m Bob Hirshon for AAAS, the Science Society.

Indoor tanning: dangerous, but still popular. (Janneman/Wikipedia)

Monkey see, monkey eat. I’m Bob Hirshon and this is Science Update.

Peer pressure may influence some monkeys’ food choices. Erica van de Waal is a biologist at the University of St. Andrews in Scotland. Her team trained vervet monkeys to like corn that was dyed either pink or blue. Then some of them were transferred to groups with the other color preference. The newcomers usually changed their habits right away.

ERICA VAN DE WAAL (University of St. Andrews, Scotland):

And we found that they learned one color is bad and they adapted to the new groups, and then switched their color preference, just by looking what the others were doing.

HIRSHON:
Van de Waal says that in the wild, monkeys may do this not just to take advantage of local resources, but also to fit in socially. That’s because the only monkeys that stuck to their old diets were dominant males that took over the new group.  I’m Bob Hirshon for AAAS, the Science Society.

Vervet monkeys joining new groups trained to prefer pink dyed corn rapidly start preferring pink corn, too. (University of St. Andrews)

Prehistoric lead pollution. I’m Bob Hirshon and this is Science Update.

Researchers in Spain have found evidence of man-made lead pollution – as far back as 3,900 years ago. The evidence comes from sediments in an alpine lake. According to paleontologist Gonzalo Jimenez Moreno, the sediments’ chemistry reveals periodic spikes in atmospheric lead – starting in the Bronze Age, when humans there first started mining. To isolate metals, they’d burn away the surrounding rock, releasing other elements like lead in the process.

GONZALO JIMENEZ MORENO (University of Granada, Spain):

So in order to obtain the copper, which is what they really wanted to obtain, there’s always lead that goes into the atmosphere. This process is called smelting.

HIRSHON:
Other peaks occurred during the Roman Empire, and of course, the modern Industrial Revolution. One bit of good news: after hitting record highs, lead levels recently started declining again, presumably because of measures like banning leaded gasoline. I’m Bob Hirshon for AAAS, the Science Society.

La Laguna de Rio Seco lagoon in Spain, where researchers recovered sediments containing signs of lead pollution from Neolithic times. (University of Granada)

An insect-inspired camera. I’m Bob Hirshon and this is Science Update.

Engineers have designed a digital camera inspired by the eyes of insects. According to John Rogers of the University of Illinois at Urbana/Champaign, the new camera is modeled after the compound eyes of ants and beetles, which are made up of hundreds of tiny, rounded lenses.

JOHN ROGERS (University of Illinois at Urbana/Champaign):

You end up with an imaging device that has some pretty unique and interesting characteristics: very wide angle field of view – 180 degrees or more, very high acuity to motion and essentially infinite depth of field, so objects very close to the eye are in a crisp focus just as objects distant away from the eye are as well.

HIRSHON:

He says conventional cameras rely on a single, flattened lens to capture images at wide angles, which results in distorted images. Potential uses for the camera include military surveillance and medical imaging. I’m Bob Hirshon, for AAAS, the science society. 

The new digital cameras exploit large arrays of tiny focusing lenses and miniaturized detectors in hemispherical layouts, just like eyes found in arthropods. (John A. Rogers/University of Illinois at Urbana-Champaign)

A helpful alien invasion. I’m Bob Hirshon and this is Science Update.

Invasive species usually cause big problems, and the arrival of the European green crab in US waters has been no exception. The little crabs eat scallops, clams and other important shellfish. But a new study published in the journal Ecology reveals an upside to the crustacean invasion: the crabs are driving away a plant-eating crab that’s been devastating salt marshes in the Northeast. Researchers were surprised to see the marshes recovering, and when they investigated, they found that the invading crabs had taken over the marsh-eating crabs burrows.

In other news, UC San Diego scientists are studying the tails of sea horses to help them develop new robotic arms. The tails are made of 36 square segments composed of minerals and protein. The team hopes to imitate the seahorse’s combination of flexibility and armor. I’m Bob Hirshon, for AAAS, the science society.

European green crab. (© Hans Hillewaert / CC-BY-SA-3.0/Wikipedia)

How ears protect themselves. I’m Bob Hirshon and this is Science Update.

(SFX: Ozzy Osbourne concert)

Rock concerts and fireworks didn’t exist when ears evolved, which is why today we’re so vulnerable to hearing loss. But now, scientists have discovered that short-term hearing loss can protect against permanent ear damage. University of California, San Diego neuroscientist Allen Ryan and his colleagues found that in mice, exposure to loud noise turns on a gene called p2rx2, which causes temporary hearing impairment. Mice without a functional p2rx2 gene don’t experience temporary hearing loss, but are more likely to develop permanent hearing loss as noise levels go up.

ALLEN RYAN (UCSD Medical School):

Temporary loss is part of the protection mechanism of the ear.

(Ozzy Osbourne concert)

HIRSHON:

But, Ozzy Osbourne fans, there are limits: the ear can take only short bouts of loud noise before sustaining permanent damage. I’m Bob Hirshon, for AAAS, the science society. 

Ears evolved before the invention of rock music, explosions, and other loud man-made noise. (Jupiter Images)

From useless to nutritious. I’m Bob Hirshon and this is Science Update.

Cellulose, or plant fiber, is the most abundant organic compound on earth. Unfortunately, only termites and ruminants, like cows, can digest it. But now, bioengineer Percival Zhang and his colleagues at Virginia Tech have found a way to convert cellulose into nutritious starch. Zhang’s method uses several enzymes to break down cellulose – from any plant source – and reassemble its components into a starch called amylose.

PERCIVAL ZHANG (Virginia Tech):

And this process is pretty simple.

HIRSHON:

Zhang explains that if fuel costs and the global population continue to rise, so will the cost of food. He says this technique could not only provide cheap nutrition to hungry parts of the world, but could also be useful in processed foods, since the resulting starch is both high in fiber and reduces the risk of obesity and diabetes. I’m Bob Hirshon for AAAS, the Science Society.

Dinner? Cellulose from corn stover left over from farming could be converted to digestible amylose starch. (Royalbroil/Wikipedia)

A brain for numbers. I’m Bob Hirshon and this is Science Update.

Researchers have pinpointed a tiny hotspot in the brain dedicated to the recognition of numerals. By directly recording the brain’s electrical activity, Stanford University Medical Center neuroscientist Josef Parvizi and his colleagues determined that this area responds specifically to numeric symbols, rather than to numbers that are spelled out or that sound like other words.

JOSEF PARVIZI (Stanford University Medical Center):

We found that this numeral hotspot is almost like an island within a large sea of neuronal populations created by nature to process this type of stimuli.

HIRSHON:

He says this illustrates how evolution has prepared the brain for rapid learning, since no one has an innate ability to recognize numerals. He adds that the findings have the potential to help the nearly 25% of adults who have some type of difficulty processing numbers. I’m Bob Hirshon, for AAAS the science society.  

About a quarter of adults have problems with numeracy. This makes it harder for them to understand basic mathematical concepts. An area of the brain dedicated to numeral recognition may play a role. (Jupiter Images)

Changing hare color.  I’m Bob Hirshon and this is Science Update.

Snowshoe hares are famous for molting from brown to white when winter comes, to blend in with the snow. But recently, climate change has been delaying snowfall in the Rocky Mountains, and more and more white hares are showing up on a brown background. That makes them easy snacks for everything from mountain lions to owls. University of Montana population ecologist Scott Mills and his colleagues found that day length, rather than snowfall, initiates the color change.

L. SCOTT MILLS (University of Montana):

So the second week of October, no matter how much snow is on the ground, they start to go from brown to white. So they’re not like a chameleon where they can just change from brown to white if snow is there.

HIRSHON:

Climate experts expect 50 fewer snowy days by the turn of the century, which means a lot more snowshoe hares could become sitting ducks. I’m Bob Hirshon, for AAAS, the science society.

Fighting pain with cold. I’m Bob Hirshon and this is Science Update.

Neuralgia is a painful condition caused by nerves damaged by diabetes or trauma. At a recent meeting of the Society for Interventional Radiology, scientists from Stony Brook University described a new treatment called cryoneurolysis that uses freezing temperatures to relieve the pain. Doctors guide a needle-like probe to the problem nerves; the probe cools to minus 10 or more below zero Celsius, freezing the nerves’ outer layers and reducing their ability to transmit pain signals.

In other cryo related news, researchers at the Mayo Clinic are using probes cooled to minus 100 degrees Celsius to kill lung cancer tumors. The technique is called cryoablation and while it doesn’t stop the spread of metastatic lung cancer completely, the doctors report slowing it down significantly. I’m Bob Hirshon, for AAAS, the science society.

A medically useful parasite. I’m Bob Hirshon and this is Science Update.

An aquatic parasite may help improve skin grafts and other surgeries. Bioengineer Jeff Karp of the Brigham and Women’s Hospital in Boston is developing a new medical adhesive, modeled after the spiny-headed worm.

JEFFREY KARP (Brigham and Women’s Hospital):

It has this needle-like structure, called a proboscis. Which it pushes into the intestine of fish. And then only the tip part swells.

HIRSHON:
That locks the worm into place so it can feed. Karp’s adhesive uses an array of microneedles, each as thin as two or three human hairs, which swell in a similar way to stick to tissue. The adhesive could greatly improve skin grafts, which are currently attached with bulky staples and often don’t stay flush with the body. It could also be used in other wound dressings, and Karp says degradable versions could even be used as internal bandages. I’m Bob Hirshon for AAAS, the Science Society.

A medical adhesive inspired by a worm. (Karp Lab/Brigham and Women's Hospital)

21^st century computer wizards.  I’m Bob Hirshon and this is Science Update.

(SFX: CodeSpells video game sounds)

Can 10-year-olds learn to program computers? University of California, San Diego graduate students Sarah Esper and Stephen Foster think so. They’ve designed an immersive 3-D video game called CodeSpells. In it, players become wizards who cast spells in the form of computer code to vanquish monsters.

SARAH ESPER (UCSD):

And so you’re set into this 3-D and our job is to read, write, modify and cast spells, or Java programs. We do provide snippets of code in a spellbook.

HIRSHON:

So far, the game has been a hit with 4^th graders at a local elementary school. She says the video game format keeps students hooked, as they learn college-level programming skills with minimal instruction. I’m Bob Hirshon, for AAAS, the science society.

UCSD Computer Science graduate student Sarah Esper looks on as 4th graders play a video game designed to teach computer programming skills. (Ioana Patringenaru/UCSD Jacobs School of Engineering)

Tiny sponges in the blood. I’m Bob Hirshon and this is Science Update.

Handy new sponges can soak up tough spills, like snake venom or bacterial toxins. And they’re small enough to inject into the bloodstream. Nanoengineer Liangfang Zhang of the University of California, San Diego has been developing the so-called nano-sponges. He explains that certain toxins puncture red blood cells. The nanosponges are cloaked in red blood cell membranes, so they act like decoys, and absorb the toxins instead and seal them in. In mouse experiments, Zhang’s team showed that the nanoparticles are safe to use, even as a preventive treatment.

LIANGFANG ZHANG (University of California, San Diego):

If they find something bad, they will clean them up. If nothing happens, they just circulate, and then they go to the liver.

HIRSHON:
Because they’re made from biologically compatible materials, the liver metabolizes them safely. Zhang’s team is now planning human trials. I’m Bob Hirshon for AAAS, the Science Society.

Left: Cross-section of a nanosponge. Right: Transmission Electron Microscopy (TEM) of a nanosponge. (UCSD Jacobs School of Engineering)

Aliens invade Florida. I’m Bob Hirshon and this is Science Update.

Giant East African land snails, up to eight inches long, have become a major pest in South Florida. According to entomologist Trevor Smith of the Florida Department of Agriculture, the snails eat virtually all kinds of plants, and also voraciously seek out calcium for their shells.

SMITH:
So if they can’t find limestone or maybe a cement block or something on the ground, they’ll just climb up on the wall of the house and start eating the stucco. So not only are they a plant pest, but they can actually eat your house.

HIRSHON:

It’s not clear how the snails got here, but in just nineteen months since the first sighting, their population has exploded. Thanks to a massive public information campaign, regular citizens have identified many infestations. Authorities then hand-collect the snails and leave baits laced with iron, which kills the stragglers. I’m Bob Hirshon for AAAS, the Science Society.

A giant African land snail. (Alexander R. Jenner/Wikipedia)

Microscopic medical implants. I’m Bob Hirshon and this is Science Update.

When electronic devices reach the end of their lives, we’re faced with the problem of disposing of them. That’s especially difficult when the device is implanted inside your body. For example, devices that monitor blood chemistry, or deliver medicines. Now, researchers at the University of Illinois, Urbana-Champaign are designing medical implants that break down into harmless substances when their job is complete. The team is also working on disposable water quality monitors that could be tossed into lakes and streams, and other electronics that simply dissolve when their job is complete.

In other microelectronic news, scientists at UC-San Diego are developing microrockets and micromotors to power tiny devices through the body. The propulsion units use the acids, salts and other naturally-occurring compounds in the body as their fuel. I’m Bob Hirshon, for AAAS, the science society.

Why trees live so long.  I’m Bob Hirshon and this is Science Update.

The oldest age ever recorded for a human being is 122 years. But the oldest known tree is a 5,000 year-old bristlecone pine still thriving in the mountains of California. Listener Claudine wants to know why some trees live so long. We consulted applied forest ecologist Sarah Johnson of the Nature Conservancy. She says the longest-lived trees have several things in common: they put a lot of energy into the maintenance and defense of their tissues, and they grow extremely slowly, compared to other plants.

SARAH JOHNSON (Nature Conservancy):

Slower growth generally means that you might have the chance to live a bit longer.

HIRSHON:

She adds that the oldest trees live in inhospitable environments, which slows down their growth even more. And if you have a science question, give us a call at 1-800-why-isit.  If we use your question, we’ll send you a fabulous Science Update mug! I’m Bob Hirshon for AAAS, the Science Society.

Bristlecone pines can live longer than any other organism on earth. (James R Bouldin/Wikipedia)

Lasers point to a new kind of rehab. I’m Bob Hirshon and this is Science Update.

Lasers can wipe out cocaine addiction, at least in rats. This according to Antonello Bonci, scientific director of the National Institute on Drug Abuse. Bonci explains that cocaine-addicted humans have low activity in their brains’ prefrontal cortex. His team showed that healthy rats suffer the same effect when they become addicted to cocaine. And remarkably, stimulating that sluggish brain area with lasers reversed the addiction.

ANTONELLO BONCI (National Institute on Drug Abuse):

And what is extraordinary to me as a scientist is in just a session – in just a few hours – their desire to take cocaine was completely wiped out.

HIRSHON:
Although the laser treatment would be impractical in humans, Bonci says a magnetic technique, already used to treat depression, would be a good substitute. An open question is how long such a treatment would last. I’m Bob Hirshon for AAAS, the Science Society.

Cocaine addiction is one of the hardest addictions to treat. (Jupiter Images)

How monarch butterflies migrate.  I’m Bob Hirshon and this is Science Update.

Every fall, monarch butterflies migrate from North America to a few parts of Mexico.  It’s known that they use the sun as a compass.  But it was also widely assumed that they have a mental map of their route, like homing pigeons.

HENRIK MOURITSEN (University of Oldenburg, Germany):

Normally, if you want to find a few kilometer-wide goal after 3 1/2 thousand kilometers, you have to have a map.  But these guys don’t have a map.  And that’s quite surprising.

HIRSHON:
That’s biologist Henrik Mouritsen of the University of Oldenburg in Germany.  His team proved the butterflies rely on their compass alone, by moving a population from Ontario 1,500 miles west to Calgary. The relocated butterflies still tried to migrate southwest, which wasn’t the right direction anymore.  Mourtisen says that normally, simply following the coastline helps the monarchs stay on track.  I’m Bob Hirshon for AAAS, the Science Society.

Monarch butterflies migrating through Texas. (David R. Tribble/Wikipedia)

Sound and memory. I’m Bob Hirshon and this is Science Update.

(SFX: “Pink noise” stimuli)

Scientists have found that playing sounds like this to people during deep sleep can enhance their short-term memory. Deep sleep, also known as slow-wave sleep, helps reinforce our memories from the previous day. University of Tübingen researchers had volunteers memorize lists of paired words before bedtime. While they slept, the scientists played them sounds that were synchronized with their own slow-wave brain rhythms. Neuroscientist Jan Born explains.

JAN BORN (University of Tübingen):

This enhances the brain oscillatory activity, like when you push a swing in the right moment.

HIRSHON:

The next day, the volunteers remembered the word associations better than when either no sound was played or when sounds were played that were out-of-synch with their brain rhythms. In addition to boosting short-term memory, the research could be used in the treatment of sleep disorders or even epilepsy. I’m Bob Hirshon, for AAAS, the science society. 

An electroencephalogram of slow-wave sleep. (Mr Sandman/Wikipedia)

Guinea pig fruit flies. I’m Bob Hirshon and this is Science Update.

Cuts, burns and other serious wounds affect 180 million Americans each year. Researchers from UC San Diego and the City College of New York are studying fruit flies to understand wound healing. Even though human skin and fruit fly chitin are very different, the enzymes and other molecules brought to bear in healing are common to both species.  The team recently found eight genes involved in healing that weren’t previously suspected. Now they’re figuring out what those same genes do in humans. The goal is to find new treatments for difficult to heal wounds.

In other fruitfly news, scientists at Tel Aviv University are using fruitflies to test a potential treatment for Parkinson’s disease. They’re finding that the compound mannitol can restore the function of a key brain protein impaired in Parkinson’s. I’m Bob Hirshon, for AAAS, the science society.

Fruit flies offer many clues to human disease. (André Karwath/Wikipedia)

What do geckos stick to?  I’m Bob Hirshon and this is Science Update.

Science labs aren’t all about petri dishes and microscopes.  For instance, University of Akron biologist Alyssa Stark harnesses small lizards called geckos to a tether, and gently yanks them off various surfaces.  The tether’s attached to a force sensor.

ALYSSA STARK (University of Akron):

So we kind of are sliding them across the surface, and trying to measure the actual force it takes to make them slip. And our definition of slip is all four of their feet start sliding on that surface.

HIRSHON:
The lizards are interesting to scientists because they can run upside down on wet surfaces – so they’re strongly adhesive but easily detached.  Stark’s lab has found that generally, the more the surface itself repels water, the better the gecko sticks to it.  The results may help develop synthetic adhesives – from reusable underwater tape to internal bandages – that stick and release like gecko feet.  I’m Bob Hirshon for AAAS, the Science Society.

Researchers test the stickiness of gecko feet. (University of Akron)

Olympic-level thinking.  I’m Bob Hirshon and this is Science Update.

Elite athletes have an enhanced mental agility that matches their physical prowess.  This according to a study led by University of Illinois cognitive neuroscientist Art Kramer.  He and graduate student Heloise Alves studied Brazilian volleyball players training for the Olympics.  Compared to closely matched non-athletes, the Olympians performed better on a variety of mental challenges, like remembering the locations of items on a computer screen.

ART KRAMER (University of Illinois):

We also found benefits for a number of other tasks that measure aspects of executive control, things like planning, scheduling, dealing with ambiguity, and multitasking.

HIRSHON:
Many of these abilities obviously apply to volleyball.  It’s not clear whether the athletic training itself developed these mental muscles, but Kramer’s trying to find out if physical conditioning can improve sedentary adults’ cognitive performance. I’m Bob Hirshon for AAAS, the Science Society.

Elite athletes may get cognitive benefits from their training. (Jupiter Images)

The world inside a pitcher plant.  I’m Bob Hirshon and this is Science Update.

Carnivorous pitcher plants are more than just interesting oddities. According to community ecologist Ben Baiser at Harvard Forest in Massachusetts, each pitcher plant contains a unique and complex food web.

BEN BAISER (Harvard Forest):

The plants produce new leaves every spring and when each leaf opens, they’re completely sterile, they fill with rainwater, and then an insect comes and falls in.

HIRSHON:

Tiny flies shred the insects, allowing bacteria to break them down. Protozoans feed on the bacteria, only to be gobbled up by microscopic animals, whose waste provides nutrients for the pitcher plant. If one element in the food web changes, such as too many trapped insects, it affects the entire web. Baiser says identifying the factors that make each pitcher plant’s food web unique can help scientists understand food webs in much larger ecosystems, like oceans and lakes. I’m Bob Hirshon, for AAAS, the science society.

The northern pitcher plant, Sarracenia purpurea. Each leaf holds an aquatic food web comprised of bacteria, protozoa, and insect larvae. These food webs vary greatly in structure and composition. (Rob Lilieholm)

Artery-clogging energy drinks? I’m Bob Hirshon and this is Science Update.

Diets high in red meat can contribute to clogged arteries. Now, scientists think gut microbes may be involved. Biochemist Stanley Hazen of the Cleveland Clinic says a substance called carnitine is common in red meat. Gut bacteria use carnitine for energy, producing a waste product called TMAO. TMAO, in turn, promotes clogged arteries. Hazen and his colleagues found that both mice and humans with carnitine-rich diets developed more heart disease.

STANLEY HAZEN (The Cleveland Clinic):

Chronic exposure to dietary carnitine can shift your intestinal microbe composition and make you more likely to generate TMAO, this metabolite in the blood that very strongly tracks with risk for heart attack, stroke and death.

HIRSHON:

But red meat isn’t the only culprit. It turns out that carnitine is also a common ingredient in many popular energy drinks.

HAZEN:

And a typical energy drink will have as much carnitine in it as a whole steak.

HIRSHON:

I’m Bob Hirshon, for AAAS, the science society. 

Energy drinks promise to make you a better athlete, but could some be bad for your heart? (Jupiter Images)

Another side of cholesterol. I’m Bob Hirshon and this is Science Update.

We know cholesterol as that fat that circulates in the blood, one type of which can form a dangerous coating of plaque in our arteries. But cancer researchers are turning to cholesterol to help them reprogram tumor cells. In the journal Therapeutic Delivery, scientists at the University of Colorado Cancer Center describe using microscopic cholesterol rafts to ferry DNA into cancer cells. One inside, the DNA reprograms the tumor cells’ genetics so they stop dividing.

In other cholesterol news, Washington University scientists report in the journal Cell Metabolism that they’re developing cholesterol-reducing eyedrops to treat age related macular degeneration, or AMD. AMD leads to blindness because macrophages—the body’s garbage collecting cells—get clogged up with cholesterol. The eyedrops contain a compound that in laboratory animals helped unclog the cells, and stop progression of the disease. I’m Bob Hirshon, for AAAS, the science society.

Cholesterol, despite ts bad rap, is essential to many biological processes. (Sbrools/Wikipedia)

The development of sharing. I’m Bob Hirshon and this is Science Update.

Anyone who has raised young children knows that sharing doesn’t come easy. But a University of Michigan study suggests that by the age of three, children understand that they should share things. They’re just too focused on their own desires to put this into practice, according to developmental psychologist Craig Smith.

CRAIG SMITH (Universty of Michigan):

The youngest kids we studied all the way through the 8-yer-olds seemed really clear that when people are equally deserving, things should be divided equally.

HIRSHON:

But when the researchers gave them the opportunity to share stickers with other children, the three to six-year-olds hoarded them for themselves. Only the older kids shared their stickers equally. Smith says in the moment, the older kids emphasized the happiness of others over personal gain.

SMITH:

Whereas the younger kids seemed to get sucked a bit more into thinking more about just their own desires.

HIRSHON:

This suggests that kids may not be able align their behavior with their ethics before age seven. I’m Bob Hirshon, for AAAS, the science society.

New research shows that small children do understand the concept of fairness, but can't yet put it into practice. (Jupiter Images)

Off-road robots. I’m Bob Hirshon and this is Science Update.

Inspired by lizards and insects, researchers at Georgia Tech have designed a six-legged robot that can walk efficiently over sand. Chen Li and his colleagues ran computer simulations based on animal locomotion to determine the most optimal leg shapes for traversing unstable terrain. They used a 3-D printer to produce the legs, which they attached to a modified robotic toy.Then they tested their designs on granular surfaces, according to Li’s mentor, physicist Daniel Goldman.

DANIEL GOLDMAN (Georgia Tech):

Something that looked very close to a perfect “c” but not exactly a perfect “c”, seemed to be the leg which allowed the robot to generate the most lift to keep itself high out of the ground and also to generate a lot of thrust to push itself forward with each step.

HIRSHON:

The research, which appears in the journal Science, could improve the design of mobile robots, including future Mars rovers. I’m Bob Hirshon, for AAAS, the science society.

Daniel Goldman and Chen Li show off their robot that can walk on granular surfaces. (Chen Li, Tingnan Zhang, and Daniel Goldman)

Fairy circles’ cause and effect.  I’m Bob Hirshon and this is Science Update.

On the edge of the Namibian desert, mysterious so-called “fairy circles” appear. They’re circles of bare dirt, surrounded by a ring of thick perennial grass.  Now, University of Hamburg biologist Norbert Juergens has found that the circles are made by sand termites, which eat underground grass roots. Although that leaves the inner circle barren, it also helps the soil hold water – because there are no plants to take up the water and release it into the air. Through the long dry season, the water sustains both the termites and the grasses on the circle’s perimeter.

NORBERT JUERGENS (University of Hamburg, Germany):

The termites create a permanent water store, and a permanent plantation of grasses.

HIRSHON:
These perennial grasses also attract other insects and small mammals.  So the termites’ fairy circles actually create a rich ecosystem, in what might otherwise be a barren landscape.  I’m Bob Hirshon for AAAS, the Science Society.

"Fairy circles" in Namibia's Marienfluss valley. (Thorsten Becker/Wikimedia)