Topics

316

EEE / Designing nutritional games and brains for space

« on: November 20, 2016, 05:49:28 PM »

Thirty Broadcom MASTERS finalists from around the United States convened in Washington, D.C. in October. The middle school students participated in team challenges and presented their research to judges and the public during the Broadcom MASTERS Science and Engineering Project Showcase.

Ananya Ganesh, from Georgia, was excited to meet other finalists and check out the competition. “Their projects are just impressive,” she said, wearing several electrodes on her face.

Ganesh has bruxism, a condition which causes her to clench her jaw. She built a device that detects signals coming from a muscle when it contracts and provides biofeedback to the wearer. “As soon as you clench, a light comes on and it alerts someone to stop clenching to help lessen the pain,” she said. Ganesh won the 2016 Science Award at the competition.

317

EEE / What not to do when your kid tells a lie

« on: November 20, 2016, 05:48:42 PM »

At the ripe old age of 3, my older daughter has begun flirting with falsehoods. So far, the few lies she has told have been comically bad and easy to spot. Her dad and I usually laugh at them with an amused, “Oh, yeah?” But now that I’ve stopped to consider, that strategy seems flawed.

While reporting a story on adult lying, I had the pleasure of talking with developmental psychologist Victoria Talwar of McGill University, who studies lying in children. I told her about an episode last week, in which I watched my older daughter swat my younger one. Instead of simply accepting reality and scolding her, my reaction was to question it further. “Did you just hit your sister?” After a pause, the guilty one offered a slightly confused “no.”

My accusatory question had created conditions ripe for this lie to be spawned. And now, as Talwar pointed out, I was dealing with two things: the hitting and the lie. “If you catch them in a transgression, just deal with the transgression,” she told me. “Don’t give them a chance to lie by asking a question you already know the answer to.”

Lying, it turns out, is actually a sign of something good happening in the developing brain. Dishonesty requires some mental heavy lifting, like figuring out what another person knows and how to use that information to your advantage. Many kids start experimenting with stretching the truth between ages 3 and 4. “In a way, it’s almost like they’re exercising a new ability,” Talwar says. “ And part of that is, ‘Mommy doesn’t know what I just did.’”

That thought sounds simple, but it’s actually quite profound. It means that a child is developing what scientists call theory of mind — the ability to understand the perspectives of other people and realize that those perspectives are sometimes different. It also means that a friend of mine who has put in years of hard work convincing her 5-year-old daughter that she is all-seeing and all-knowing may be out of luck soon. With a quickly solidifying theory of mind, her kid will wise up to her mom’s tall tale, if she hasn’t already.

For the rest of us parents who can’t maintain an elaborate charade like that, Talwar says the key is to create an environment that fosters truth-telling. “One of the most important ways to encourage honesty is to acknowledge it when you see it,” she says. If my daughter had answered yes to my ridiculous question, I should have thanked her for telling the truth before addressing the hitting. “Make sure they understand that you’ve appreciated that bit,” Talwar says.

Another strategy to minimize lies, as simple as it sounds, is to ask your kid to tell you the truth. Sweet little children, bless their hearts, just might comply, as a study from Talwar and colleagues suggests.

And remember, if you want your kid to value honesty, you should check yourself. One study found that children were more likely to lie after having been lied to. And lest you think you can skirt under their underdeveloped lie radars, consider a recent study. Children ages 6 to 11 were actually not terrible at detecting white lies. When watching a video of an adult or child saying that they thought a hunk of used, dingy soap was a good gift, or that a bad drawing of a person was actually good, children were about as good as adults in spotting fibs.

The result was interesting because it meant that children weren’t just swallowing adults’ lies, says study coauthor Michelle Eskritt of Mount St. Vincent University in Halifax, Canada. For these sorts of lies, kids weren’t just assuming that everyone was telling the truth, she says.

Now that my daughter is learning about honesty, we’ve been having some fun conversations about what the truth really is. These days she likes it when I make up stories that feature her telling elaborate whoppers. My lies about her lies really crack her up.

318

EEE / Protein linked to Parkinson’s travels from gut to brain

« on: November 20, 2016, 05:47:52 PM »

SAN DIEGO — Over the course of months, clumps of a protein implicated in Parkinson’s disease can travel from the gut into the brains of mice, scientists have found.

The results, reported November 14 at the annual meeting of the Society for Neuroscience, suggest that in some cases, Parkinson’s may get its start in the gut. That’s an intriguing concept, says neuroscientist John Cryan of the University College Cork in Ireland. The new study “shows how important gut health can be for brain health and behavior.”

Collin Challis of Caltech and colleagues injected clumps of synthetic alpha-synuclein, a protein known to accumulate in the brains of people with Parkinson’s, into mice’s stomachs and intestines. The researchers then tracked alpha-synuclein with a technique called CLARITY, which makes parts of the mice’s bodies transparent.

Seven days after the injections, researchers saw alpha-synuclein clumps in the gut. Levels there peaked 21 days after the injections. These weren’t the same alpha-synuclein aggregates that were injected, though. These were new clumps, formed from naturally occurring alpha-synuclein, that researchers believe were coaxed into forming by the synthetic versions in their midst.

Also 21 days after the injections, alpha-synuclein clumps seemed to have spread to a part of the brain stem containing nerve cells that make up the vagus nerve, a neural highway that connects the gut to the brain. Sixty days after the injections, alpha-synuclein had accumulated in the midbrain, a region packed with nerve cells that make the chemical messenger dopamine. These are the nerve cells that die in people with Parkinson’s, a progressive brain disorder that affects movement.

After reaching the brain, alpha-synuclein spreads thanks in part to brain cells called astrocytes, a second study suggests. Experiments with cells in dishes showed that astrocytes can store up and spread alpha-synuclein among cells. That work was presented by Jinar Rostami of Uppsala University in Sweden at a news briefing on November 14.

The gradual accumulation and spread of alpha-synuclein caused trouble in the mice. As alpha-synuclein clumps slowly crept brainward, the mice began exhibiting gut and movement problems. Seven days after the injections, the mice’s stool was more plentiful than usual. Sixty and 90 days after the injections — after clumps of alpha-synuclein had reached the brain — the mice performed worse on some physical tests, including getting a sticker off their face and flipping around to shimmy down a pole headfirst. In many ways, the mice resembled other mice that have mutations that cause Parkinson’s-like symptoms, Challis says.

An earlier study turned up evidence that clumps of alpha-synuclein can move from the gut to the brain stem in rats, but those experiments looked at shorter time scales, Challis says. And previous work monitored the movements of the injected alpha-synuclein, as opposed to the alpha-synuclein clumps that the mice produced themselves.

The idea that alpha-synuclein can spread from the gut to the brain is very new, says Alice Chen-Plotkin, a clinician and Parkinson’s researcher at the Hospital of the University of Pennsylvania. These new results and others have prompted scientists to start looking outside of the brain for the beginning stages of the disease, she says. “Increasingly, people are wondering if it starts earlier.”

Some evidence suggests that the gut is a good place to look. People with Parkinson’s disease often suffer from gut problems such as constipation. And in 2015, scientists reported that a group of Danish people who had their vagus nerves severed were less likely to develop Parkinson’s disease. Cut alpha-synuclein’s transit route from the gut to the brain, and the disease is less likely to take hold, that study hints.

It’s not clear why alpha-synuclein accumulates in the gut in the first place. “There are a lot of theories out there,” Challis says. Bacteria may produce compounds called curli that prompt alpha-synuclein to aggregate, a recent study suggests. Pesticides, acid reflux and inflammation are other possible culprits that could somehow increase alpha-synuclein clumps in the gut, Challis says.

319

EEE / ‘Void’ dives into physics of nothingness

« on: November 20, 2016, 05:47:17 PM »

In empty space, quantum particles flit in and out of existence, electromagnetic fields permeate the vacuum, and space itself trembles with gravitational waves. What may seem like nothingness paradoxically teems with activity.

In Void: The Strange Physics of Nothing, physicist and philosopher James Owen Weatherall explores how physicists’ beliefs about nothingness have changed over several revolutionary periods. The void, Weatherall argues, is physics distilled to its bare essence. If physicists can’t agree on the properties of empty space, they won’t be able to explain the physics of planets or particles either.

Scientists have argued over nothingness since the early days of physics. Vacant space was unthinkable to Aristotle, and Descartes so abhorred the idea of a vacuum that he posited that an invisible “plenum” suffused the gaps between objects. But Isaac Newton upended this view, arguing that space was just a barren container into which matter is placed.

Since then, physicists have continued to flip-flop on this issue. The discovery in the mid-1800s that light is an electromagnetic wave led scientists to conclude that a vibrating medium, an “ether,” filled space. Just as sound waves vibrate the air, physicists thought there must be some medium for light waves to ripple. Albert Einstein tore down that idea with his special theory of relativity. Since the speed of light was the same for all observers, no matter their relative speeds, he reasoned, light could not be traveling through some absolute, stationary medium. But he later predicted, as part of his general theory of relativity, that space itself can ripple with gravitational waves (SN: 3/5/16, p. 6) — suggesting that the void is not quite empty.

Under the modern view of quantum physics, various fields pervade all of space, and particles are simply excitations, or waves, in these fields. Even in a vacuum, experiments show, fluctuating fields produce a background of transient particles and antiparticles. Does a space pulsating with gravitational waves and bubbling with particles really qualify as empty? It depends on the scientific definition of “nothing,” Weatherall argues, which may not conform to intuition.

Weatherall serves readers a fairly typical buffet of physics theories, dishing up Newtonian mechanics, relativity, quantum mechanics and a small helping of string theory. But he does this through a lens that highlights connections between those theories in a novel way. Weatherall contends, for instance, that differing notions of nothingness between theories of general relativity and quantum mechanics could help explain why scientists are still struggling to unite the two ideas into one theory of quantum gravity.

Exploring the physics of nothing demands quite a bit of wading through the physics of something, and it’s not always clear how the threads Weatherall is following will lead back to the void. When he finally makes these connections, though, they often reveal insights that are missed in the typical focus on things of substance.

320

EEE / Marijuana use weakens heart muscle

« on: November 20, 2016, 05:46:18 PM »

Marijuana use is associated with an almost doubled risk of developing stress cardiomyopathy, a sudden life-threatening weakening of the heart muscle, according to a new study. Cannabis fans may find the results surprising, since two-thirds believe the drug has no lasting health effects. But as more states approve recreational use, scientists say there’s a renewed urgency to learn about the drug’s effects.

An estimated 22 million Americans — including 38 percent of college students — say they regularly use marijuana. Previous research has raised cardiovascular concerns: The drug has been linked to an increased risk of heart attack immediately after use, and a 2016 study in rodents found that one minute of exposure to marijuana smoke impairs the heart’s inner lining for 90 minutes, longer than tobacco’s effect.

The new study, presented November 13 during the American Heart Association’s Scientific Sessions, examined the occurrence of stress cardiomyopathy, which temporarily damages the tip of the heart.  Researchers from St. Luke’s University Health Network in Bethlehem, Pa., searched a nationwide hospital database and found more than 33,000 admissions for stress cardiomyopathy from 2003 to 2011. Of those, 210 were identified as marijuana users, and had about twice the odds of developing the condition, said Amitoj Singh, who led the study. Young men were at highest risk and more likely to go into cardiac arrest despite having fewer cardiovascular risk factors. Notably, the number of marijuana-linked cardiomyopathies increased every year, from 17 in 2007 to 76 in 2011. “With recent legalization, I think that’s going to go up,” Singh said.

321

EEE / An echidna’s to-do list: Sleep. Eat. Dig up Australia

« on: November 20, 2016, 05:45:36 PM »

With no nipples and reptilelike eggs, short-beaked echidnas look like a first draft of a mammal. Yet, as Australia’s other digging mammals decline from invasive predators, the well-defended echidna is getting new love as an ecosystem engineer.

The only mammals today that lay eggs are the four echidna species and the duck-billed platypus. Eggs are probably a holdover from the time before mammals split from reptiles. Each year or so, the short-beaked echidna (Tachyglossus aculeatus) lays one leathery egg “about the size of a grape,” says Christine Cooper of Curtin University in Perth. Instead of constructing a nest, mom deposits the egg in her version of a kangaroo pouch and waddles around with it.

When the egg hatches about 10 days later, two patches of pores in mom’s pouch ooze milk, and the baby laps it off her skin. The puggle, as a baby echidna is called, hitchhikes for weeks as mom forages. The ride ends, however, when the puggle starts growing spines. “Then mum’s like, ‘Nope, no more,’ and she will put [baby] into a burrow,” Cooper says.

Puggles live in mom’s pouch until they get prickly.
BEN NOTTIDGE/ALAMY STOCK PHOTO

Foraging echidnas claw around and poke their snouts into termite or ant nests, flicking out a long gooey tongue to flypaper up insects. The goo comes from unusually large salivary glands, but a quick echidna lick doesn’t slime. When Cooper wears sandals to visit captive echidnas, she says, “it’s ‘ooh, that tickles!’ ”

Echidnas’ toes point backward on their hind paws but forward on the front, and their short legs slant outward in a bit of a reptile sprawl, says Christofer Clemente of University of the Sunshine Coast in Sippy Downs, Australia. They rock side to side as they walk, moving both left, then both right feet. They can’t run, but they’re strong diggers, Clemente says. They not only claw around for food, but also defend their soft undersides by quick-digging into the ground, spikes up.

Acceleration-sensing instruments strapped onto short-beaked echidnas show they spend about 12 percent of their day excavating, researchers report in the Oct. 15 Journal of Experimental Biology. Over a year, a single echidna churns up some 204 cubic meters of soil, the scientists calculate, as it hunts for insects or scrabbles for shelter.  That’s enough to bury more than 100 full-sized fridges. 

That digging benefits the echidna’s unusual diversity of habitat — from rainforest to desert. Echidnas don’t need to bury fridges, but soil turnover and nutrient mixing keep ecosystems humming along.

322

EEE / Oldest alphabet identified as Hebrew

« on: November 20, 2016, 05:44:40 PM »

SAN ANTONIO — The world’s earliest alphabet, inscribed on stone slabs at several Egyptian sites, was an early form of Hebrew, a controversial new analysis concludes.

Israelites living in Egypt transformed that civilization’s hieroglyphics into Hebrew 1.0 more than 3,800 years ago, at a time when the Old Testament describes Jews living in Egypt, says archaeologist and epigrapher Douglas Petrovich of Wilfrid Laurier University in Waterloo, Canada. Hebrew speakers seeking a way to communicate in writing with other Egyptian Jews simplified the pharaohs’ complex hieroglyphic writing system into 22 alphabetic letters, Petrovich proposed on November 17 at the annual meeting of the American Schools of Oriental Research.

“There is a connection between ancient Egyptian texts and preserved alphabets,” Petrovich said.

That’s a highly controversial contention among scholars of the Bible and ancient civilizations. Many argue, despite what’s recounted in the Old Testament, that Israelites did not live in Egypt as long ago as proposed by Petrovich. Biblical dates for the Israelites’ stay in Egypt are unreliable, they say.

Say what
Alphabetic inscriptions on an ancient stone slab (top) have been identified by a researcher as Hebrew and translated. A drawing of the slab’s inscriptions (bottom) shows early Hebrew letters next to corresponding modern Hebrew letters (green). Inscriptions along the left edge of the slab translate as “The one having been elevated is weary to forget.” Inscriptions across the top translate as “The overseer of minerals, Ahisemach.”


© 2015 D. PETROVICH

Scholars have also generally assumed for more than 150 years that the oldest alphabetic script Petrovich studied could be based on any of a group of ancient Semitic languages. But not enough is known about those tongues to specify one language in particular.

Petrovich’s Hebrew identification for the ancient inscriptions is starved for evidence, said biblical scholar and Semitic language specialist Christopher Rollston of George Washington University in Washington, D.C. There is no way to tell which of many Semitic languages are represented by the early alphabetic system, Rollston contended.

The origins of writing in different parts of the world — including that of the alphabet carved into the Egyptian slabs — have long stimulated scholarly debates (SN: 3/6/93, p. 152). A German scholar identified the ancient Egyptian writing as Hebrew in the 1920s. But he failed to identify many letters in the alphabet, leading to implausible translations that were rejected by researchers.

Petrovich says his big break came in January 2012. While conducting research at the Egyptian Museum in Cairo, he came across the word “Hebrews” in a text from 1874 B.C. that includes the earliest known alphabetic letter. According to the Old Testament, Israelites spent 434 years in Egypt, from 1876 B.C. to 1442 B.C.

Alphabet soup
A new description of Hebrew as the world’s oldest alphabet includes these proposed early Hebrew letters (middle), with corresponding modern Hebrew letters (left) and Egyptian hieroglyphic sources for letters (right).


D. PETROVICH

Petrovich then combined previous identifications of some letters in the ancient alphabet with his own identifications of disputed letters to peg the script as Hebrew. Armed with the entire fledgling alphabet, he translated 18 Hebrew inscriptions from three Egyptian sites.

Several biblical figures turn up in the translated inscriptions, including Joseph, who was sold into slavery by his half-brothers and then became a powerful political figure in Egypt, Joseph’s wife Asenath and Joseph’s son Manasseh, a leading figure in a turquoise-mining business that involved yearly trips to Egypt’s Sinai Peninsula. Moses, who led the Israelites out of Egypt, is also mentioned, Petrovich says.

One inscription, dated to 1834 B.C., translates as “Wine is more abundant than the daylight, than the baker, than a nobleman.” This statement probably meant that, at that time or shortly before, drink was plentiful, but food was scarce, Petrovich suspects. Israelites, including Joseph and his family, likely moved to Egypt during a time of famine, when Egyptians were building silos to store food, he suggests.

A book by Petrovich detailing his analyses of the ancient inscriptions will be published within the next few months. Petrovich says the book definitively shows that only an early version of Hebrew can make sense of the Egyptian inscriptions.

323

EEE / Mysterious radio signals pack power and brilliance

« on: November 20, 2016, 02:56:35 PM »

Mysterious flashes of radio waves from deep space keep coming, but they are just as mysterious as ever.

Gamma rays might have accompanied one of these eruptions, researchers report in the Nov. 20 Astrophysical Journal Letters. This is the first time high-energy photons have been associated with these blasts of radio energy, known as fast radio bursts. If the gamma rays did come from the same place as the radio waves, then the underlying source could be roughly 1 billion times as energetic as thought.

Another burst, meanwhile, takes the record for brightest blast. The signal was bright enough to reveal details about the magnetic field between galaxies, astronomers report online November 17 in Science.

Fast radio bursts, or FRBs, have intrigued astronomers since the first one was reported in 2007 (SN: 8/9/14, p. 22). Since then, astronomers have discovered 18 in total. In most cases, a blip of radio waves lasting just a few milliseconds appears in the sky and is never seen again. Only one so far is known to repeat (SN: 4/2/16, p. 12). Most seem to originate in remote galaxies, possibly billions of light-years away. Until now, no one has detected any other frequency of electromagnetic radiation besides radio waves coming from these cosmic beacons.

A flash of gamma rays appeared at about the same time and from the same direction as a radio burst detected in 2013, James DeLaunay, a physics graduate student at Penn State and colleagues report. They pored over old data from the Swift observatory, a NASA satellite launched in 2004, to see if it recorded any surges of gamma rays that might coincide with known radio bursts.

“Gamma rays associated with an FRB would be an incredibly important thing to find,” says Sarah Burke Spolaor, an astrophysicist at the National Radio Astronomy Observatory in Socorro, N.M. But she urges caution. “We don’t have a good inkling of where a specific burst comes from.” That leaves room for other types of eruptions to occur in the vicinity just by chance. DeLaunay and collaborators calculate that the odds of that are low, about one in 800. But several researchers are taking a wait-and-see attitude before feeling more confident that the gamma rays and FRB are linked.

“It’s tantalizing, but a lot more would need to be found to be convincing,” says Jason Hessels, an astrophysicist at the Netherlands Institute for Radio Astronomy in Dwingeloo.

If the same source emits both the radio waves and gamma rays, that could rule out a couple of proposals for the causes of the eruptions. Powerful radio hiccups from pulsars, the rapidly spinning cores of dead stars, are one candidate that wouldn’t make the cut, because they aren’t known to generate gamma rays.

Collisions between two neutron stars, or between a neutron star and a black hole, look promising, says Derek Fox, an astrophysicist at Penn State and a coauthor of the study. The energy output and duration of the gamma-ray burst are a good match with what’s expected for these smashups, he says, though it’s not clear whether they happen often enough to account for the thousands of FRBs that astronomers suspect go off every day. 

No one story neatly fits all the data. “I think there are at least two populations,” says Fox. Perhaps some FRBs repeat, while others do not; some belch out gamma rays, others do not. There might be no one type of event that creates all FRBs, but rather a multitude.

That idea is tentative as well. “It’s way too early to say if there are multiple populations,” says Laura Spitler, an astrophysicist at the Max Planck Institute for Radio Astronomy in Bonn, Germany. A grab bag of cosmic calamities is plausible. But there are other astronomical events that exhibit enormous diversity, enough that all FRBs could also have just one type of trigger. “The data we have now isn’t sufficient to land on one side or the other,” Spitler says.

A more recent FRB, detected in 2015 at the Parkes radio telescope in Australia, shows off some of that diversity — and demonstrates how FRBs can be used as cosmological tools. A brief blast of radio waves from at least 1.6 billion light-years away is about four times as intense as the previous record holder. The signal’s vigor could be an intrinsic quirk of the underlying outburst, or could mean that this burst was unusually close to our galaxy — or both.

“What’s really exciting most about it is not just that it’s bright,” says Vikram Ravi, a Caltech astronomer and lead author of the study, “but really because of what we hope to use FRBs for.” This FRB was bright enough for Ravi and colleagues to deduce the magnetic field between galaxies. To do that, they measured the signal’s polarization, the alignment of radio waves imprinted by magnetized plasmas encountered en route to Earth. They found that, on average, the magnetic field is feeble, less than 21 nanogauss (or about one 10-millionth as strong as Earth’s magnetic field). That’s in line with astronomers’ theories about the strength of intergalactic magnetism.

“It’s not telling us anything that’s unexpected,” says Duncan Lorimer, an astrophysicist at West Virginia University in Morgantown who reported the first FRB in 2007. But it shows that FRBs can be used to learn more about intergalactic space, a region that is notoriously difficult to study. “It’s one thing to say we expect the magnetic field to be weak, but it’s another thing to actually measure it,” he adds. “It’s a signpost of things to come.”

This burst encountered different environments than a burst reported last year in Nature, which suggested an FRB origin in a highly magnetized environment, possibly near young stars in a remote galaxy (SN Online: 12/2/15). There’s no hint that the latest burst originated in a similar locale.

“I don’t think we contradict each other at all,” Ravi says. “Some FRBs originate in very magnetic environments and some don’t. Given that these are the only two FRBs where these measurements have been made, it’s hard to tell.”