Book lovers: Scientists have devised a way to read without cracking a volume’s spine or risking paper cuts (and no, we’re not talking about e-books). The new method uses terahertz radiation — light with wavelengths that are between microwave and infrared waves — to view the text of a closed book. The technique is not meant for your average bookworm, but for reading rare books that are too fragile to open.

Barmak Heshmat of MIT and colleagues started small, with a nine-page book of thick paper that had one letter inked on each page. By hitting the book with terahertz radiation and looking at the reflected waves, the scientists could read the letters within.
Differences in the way the radiation interacts with ink and paper allowed the researchers to pick out shadowy outlines of the letters, and a letter-recognition algorithm automatically decoded the characters. The scientists could tell one page from another by using precise timing information: On the later pages, the waves penetrated deeper before reflecting and, therefore, took longer to return.

Historians also may be able to use the technique to find an artist’s signature hidden beneath layers of a painting. Sneaking into your sister’s locked diary is another story.

Scientists have found the first experimental evidence that an atomic nucleus can harbor bubbles.

The unstable isotope silicon-34 has a bubblelike center with a paucity of protons, scientists report October 24 in Nature Physics. This unusual “bubble nucleus” could help scientists understand how heavy elements are born in the universe, and help scientists find new, ultraheavy stable isotopes.

In their quirky quantum way, protons and neutrons in a nucleus refuse to exist in only one place at a time. Instead, they are spread out across the nucleus in nuclear orbitals, which describe the probability that each proton or neutron will be found in a particular spot. Normally, due to the strong nuclear force that holds the two types of particles together, nuclei have a fairly constant density in their centers, regardless of the number of protons and neutrons they contain. In silicon-34, however, some scientists predicted that one of the proton orbitals that fills the center of the nucleus would be almost empty, creating a bubble nucleus. But not all theories agreed. “This was the reason for doing the experiment,” says coauthor Olivier Sorlin, a nuclear physicist at the National Large Heavy Ion Accelerator, GANIL, in Caen, France. “Some people didn’t believe that it would exist.”
In pursuit of the bubble nucleus, the scientists smashed silicon-34 nuclei into a beryllium target, which knocked single protons out of the nuclei to create aluminum-33. The resulting aluminum-33 nuclei were in excited, or high-energy, states and quickly dropped down to a lower energy by emitting photons, or light particles. By observing the energy of those photons, Sorlin and colleagues could reconstruct the orbital of the proton that had been kicked out of the nucleus.

The scientists found that they ejected few protons from the central orbital that theorists had predicted would be empty. While the orbital can theoretically hold up to two protons, it held only 0.17 protons on average. In silicon-34, the central proton density is about half that of a comparable nucleus, the scientists calculated, after taking into account other central orbitals that contain normal numbers of protons. (The density of neutrons in silicon-34’s center, however, is normal.)
“What they are doing is extremely difficult,” says theoretical nuclear physicist Paul-Henri Heenen of the Université libre de Bruxelles in Belgium. Silicon-34 isn’t stable, he notes. It has a half-life of less than three seconds, making it a challenge to work with.
As protons are added to nuclei, they fill orbitals in a sequential manner, according to the energy levels of the orbitals. Silicon-34 is special — it has a certain “magic” number of protons and neutrons in its nucleus. There are a variety of such magic numbers, which enhance the stability of atomic nuclei. A magic number of protons means that the energy needed to boost a proton into the next orbital is particularly high. This explains the bubble’s origin. For a proton to jump into the unfilled central orbital, it needs significantly more energy. So silicon-34’s center remains sparsely populated.

“It’s an interesting paper and indeed provides evidence” for a bubble nucleus, says nuclear physicist Jiangming Yao of the University of North Carolina, Chapel Hill. But, he says, the evidence is “not direct,” because it relies on nuclear models to calculate density. To directly measure the density of protons will require using electrons to probe the inner workings of the nucleus.

Still, the research could help scientists understand the spin-orbit interaction, the interplay between a proton’s angular momentum in its orbital and its intrinsic angular momentum, or spin. The effect is important for keeping heavy nuclei stable. Figuring out the impact of that interaction in this unusual nucleus could help scientists better predict the potential location of the “island of stability,” a theorized region of the periodic table with heavy elements that may be stable for long periods of time (SN: 6/5/10, p. 26).

What’s more, a better grasp of the spin-orbit interaction could also help scientists learn how elements are forged in rare cosmic cataclysms such as the merging of two neutron stars. There, nuclei undergo a complex chain of reactions, swallowing up neutrons and undergoing radioactive decay. Modeling this process requires a precise understanding of the stability of various nuclei — a property affected by the spin-orbit interaction.

The average American’s carbon dioxide emissions are responsible for shrinking Arctic sea ice by nearly 50 square meters each year.

That’s the implication of a new study that finds that each additional metric ton of CO₂ released into the atmosphere directly results in a 3-square-meter loss of sea ice cover at summer’s end — comparable to losing a chunk of ice with a footprint a bit smaller than a two-seat Smart car.

“For the first time now, it is possible to grasp how each one of us contributes to tangible consequences for the global climate system,” says study coauthor Dirk Notz, a climate scientist at the Max Planck Institute for Meteorology in Hamburg.
Globally, humans are responsible for the release of some 36 billion metric tons of CO₂ each year. With another trillion metric tons, the Arctic Ocean will have a completely iceless summer — possibly the first in 125,000 years. That threshold could be crossed before 2050, Notz and Julienne Stroeve of University College London estimate online November 3 in Science. Many previous studies projected that summertime ice would stick around for years longer (SN Online: 8/3/15).

“Sea ice feels so substantial when you’re standing on ice that can hold your own weight, that you can land an airplane on,” says Cecilia Bitz, an atmospheric scientist at the University of Washington in Seattle who was not involved in the study. The new work “makes it feel very fragile.”
Dwindling ice at the top of the world threatens Arctic species (SN Online: 5/14/08), can spread pollution (SN: 1/23/16, p. 9) and could open the region to transpolar shipping. In 2012, Arctic sea ice hit a record low since satellite observations began: just 3.39 million square kilometers, far below the average of 6.22 million square kilometers set from 1981 through 2010. How quickly the ice will continue to disappear remains unclear.

For their estimate, Notz and Stroeve analyzed records of Arctic sea surface temperature and minimum sea ice extent since 1953. The average extent of September sea ice declined in lockstep with the rising total amount of CO2 released from human sources, the researchers found.

This simple relationship between emissions and ice loss stems from one similarly straightforward mechanism, the researchers propose. As CO2 concentrates in the atmosphere, it strengthens the greenhouse effect, sending some heat back to Earth that would otherwise escape into space. This increases the amount of ice-warming infrared radiation hitting the Arctic, causing the outermost edge of the sea ice to retreat northward, where less sunlight hits the planet, and reducing total ice coverage.

Climate simulations underestimate this effect and don’t accurately re-create the sensitivity of Arctic sea ice to rising CO2 levels, the researchers argue. Other factors linked to sea ice loss, such as changes in ocean heat flowing from the Atlantic Ocean and in the region’s reflectiveness, were minor over the studied period compared with the increased radiative heating, Notz says.

Downplaying the role of ocean heating is a mistake, says Rong Zhang, an oceanographer at the National Oceanic and Atmospheric Administration’s Geophysical Fluid Dynamics Laboratory in Princeton, N.J. Sea ice coverage peaks in area during winter, when little light shines on the Arctic and the greenhouse effect is less important. But like the minimum, the maximum extent of Arctic sea ice has also declined over recent decades, reaching a record low in March (SN Online: 3/28/16). More observations are needed to determine whether warming from below or above the ice plays a larger role, Zhang says. “There’s not just one explanation,” she says.

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.

NEW ORLEANS — A new study highlights just how bad yo-yo dieting might be.

Women who repeatedly lose and regain as little as 10 pounds may have a higher likelihood of sudden cardiac death and cardiovascular disease — even if their bodies stay within the range of recommended weight. The results are concerning because yo-yo dieting is more prevalent among people who are typically of healthy weight, said Somwail Rasla, an internal medicine resident at Brown University in Providence, R.I. He presented the results November 15 at the American Heart Association’s annual meeting.
Rasla and his colleagues analyzed data from more than 158,000 postmenopausal women who were followed for more than 11 years as part of the Women’s Health Initiative, of whom 55,000 reported repeated weight gains and losses. During that time, 83 women suffered from sudden cardiac death, and 2,526 women died of heart disease. Yo-yo dieters of healthy weight were three times as likely to experience sudden cardiac death than women whose weight remained stable, no matter what their weight. And the risk of death from cardiovascular disease was 66 percent greater in the normal-weight dieters compared with other women.

But the observational study could not determine cause and effect, and studies on yo-yo dieting have not found consistent results, Rasla says. More research might explain how weight cycling damages the heart, he says, including studies into genetic alterations, insulin resistance and stress.

Tourists planning a visit to northern portions of the Great Barrier Reef should be prepared for some sad sights. On average, two-thirds of the nearshore coral in the mostly pristine area north of Port Douglas, Australia, has been pronounced dead by scientists who have surveyed the reef. It’s the largest coral die-off ever recorded in Great Barrier Reef history, researchers from the ARC Center of Excellence for Coral Reef Studies at James Cook University in Townsville, Australia, report.

Water temperatures off Australia rose to levels dangerous to corals starting in 2014 as a result of global warming and El Niño. In response, the corals began expelling the symbiotic algae that provide them with food, causing what is known as bleaching. In March, at the height of the bleaching event, scientists started monitoring dozens of reefs throughout the Great Barrier Reef through underwater and aerial surveys. They found huge losses in parts of the northern reef but far less damage elsewhere.

“It was a lot hotter than usual up north and not so hot down south,” notes Andrew Baird, one of the ARC Center researchers behind the new findings.

Only about a quarter of the coral in northern reefs found farther offshore died. There, the corals may have been aided by the upwelling of cooler water from the depths of the Coral Sea. And south of Port Douglas, many of the corals that had undergone bleaching appear to have recovered, regaining their algal helpers — and their brilliant colors. The cloud cover and wind from a cyclone that passed over this section of the reef in March may have brought down temperatures there, Baird says.
Many fish depend on coral reefs for food and shelter, Baird notes, and they will probably be in decline in reefs where much of the coral has died. But there is good news, too, he says: Those southern reefs should be able to provide young corals to assist with recovery in the north. And Baird has heard from colleagues that many juvenile corals survived the bleaching event and that, he says, “is also a potential source of recovery.”

Another “impossible” crystal has been found locked inside a Russian meteorite.

The specimen is a quasicrystal, a type of material that shatters the rules of crystallography by having an ordered — yet never-repeating — arrangement of atoms. The new find is only the third natural quasicrystal ever found and is the first discovered in nature before being synthesized in a lab, researchers report online December 8 in Scientific Reports.

All three natural quasicrystals came from the same meteorite, discovered in a far-flung region of eastern Russia (SN: 11/3/12, p. 24). University of Florence geologist Luca Bindi and colleagues found micrometers-wide bits of the new quasicrystal in a grain of the meteorite collected during a 2011 expedition to the site. Probing the quasicrystal with electrons showed that the mineral is composed of aluminum, copper and iron atoms arranged in a way that’s similar to the pentagon-based pattern on a soccer ball.

Like its siblings, the new quasicrystal formed before landing on Earth when a cosmic fender bender between two space rocks caused rapid melting and cooling under extreme pressures, the researchers propose. While natural quasicrystals remain rare, companies have tinkered with using lab-made versions in everything from electronics to frying pan coatings.

A quarter century after scientists proposed an idea that profoundly influenced the arc of Alzheimer’s research, they might finally find out whether they are correct. A new antibody drug called aducanumab appears to sweep the brain clean of sticky amyloid-beta protein. The drug may or may not become a breakthrough Alzheimer’s treatment — it’s too soon to say — but either way it will probably answer a key question: Have researchers been aiming at the right target?

According to the proposal, called the amyloid hypothesis, Alzheimer’s disease, estimated to affect more than 5 million people in the United States alone, is caused by abnormal buildup of A-beta protein in the brain. The buildup chokes vital brain areas and destroys nerve cells. Despite amassing much support in recent decades, the proposal hasn’t managed to shake off its detractors. Aducanumab offers a seemingly reliable and safe way to lower A-beta levels and thus test the amyloid hypothesis.
Over the course of a year, aducanumab entered the brains of people with early Alzheimer’s disease and cleared out the A-beta, scientists reported in September in Nature (SN: 10/1/16, p. 6). The trial was small — only 165 people. Yet in these people’s brains, amyloid-beta clearly declined. The higher the dose, the more A-beta cleanup.

There were hints that people on higher doses of the drug had cognitive improvements, too. If confirmed in larger studies, those cognitive benefits “would be a game changer for the field,” says Alzheimer’s researcher Eric Reiman of the Banner Alzheimer’s Institute in Phoenix. But those results “need to be treated agnostically for now,” at least until the larger studies currently under way are completed, he cautions.
There is already strong evidence that A-beta is a disease culprit: Rare genetic mutations in genes related to A-beta almost always come with Alzheimer’s, an observation that has been confirmed in mice. A-beta is toxic to nerve cells in dishes, damaging their communication abilities before eventually killing the cells outright. “All the basic science work and natural history work supports it,” says neuroscientist John Hardy of University College London, who is among those who proposed the amyloid hypothesis.
Yet contradictions exist. Cognitively healthy people have been found with A-beta accumulation in their brain (SN: 12/10/16, p. 13). And so far, scientists have found only a weak correlation between A-beta plaques and cognition, results that have led some scientists to look elsewhere — to inflammation, overzealous pruning of brain cell connections called synapses and changes to the protein tau, which is known to accumulate inside nerve cells in people with Alzheimer’s. Each of these cellular processes has also been implicated as a driver of the disease.

Identifying the true cause of Alzheimer’s is difficult because all of these processes are closely related and occur simultaneously, making it nearly impossible to study their effects in isolation. What’s more, many of the key changes might happen years, or even decades, before symptoms begin to appear. Hardy concedes that in the years since he and others introduced the amyloid hypothesis, scientists have struggled to put together a full picture of Alzheimer’s. “It is tougher than we all thought it would be,” he says.

There won’t be clear answers for several years yet. In August of 2015, larger clinical trials of aducanumab began enrolling patients around the world with the goal of finishing by 2022. As more people with Alzheimer’s are tested, researchers hope to see obvious signs of mental improvement that track reductions in brain A-beta. It’s possible that aducanumab will lower A-beta in the brain yet fail to bring meaningful improvements in symptoms. Such a result might appear to be a strike against the amyloid hypothesis, a contradiction that could prod some researchers to explore other ideas more deeply. Either way, people with Alzheimer’s and their loved ones are waiting anxiously.

A chatty source of radio waves from deep space has a little more to say. Six more blasts of radio energy, each lasting just a few milliseconds, erupted from some phenomenon outside of our galaxy, researchers report in the Dec. 20 Astrophysical Journal. This detection follows 11 previously recorded outbursts of radio waves from the same location, the only known repeater in a class of enigmatic eruptions known as fast radio bursts.

The origins of these radio bursts, 18 of which have been reported since 2007, are an ongoing puzzle (SN: 8/9/14, p. 22). The continuing barrage from this repeating source, roughly 3 billion light-years away in the constellation Auriga, implies that whatever is causing some radio bursts is not a one-time destructive event such as a collision or explosion. Flares from a young neutron star, the dense core left behind after a massive star explodes, are a promising candidate.

The latest volley was detected in late 2015, Paul Scholz, a graduate student at McGill University in Montreal, and colleagues report. Five blasts were recorded at the Green Bank Telescope in West Virginia and one at Arecibo Observatory in Puerto Rico. This object was first detected at Arecibo in 2012. Ten more blasts followed in May and June 2015 (SN: 4/2/16, p. 12).

One of Antarctica’s largest ice shelves is nearing its breaking point, scientists warn. A colossal crack in the Larsen C ice shelf grew by 18 kilometers during the second half of December, members of the Antarctic research group Project MIDAS reported January 5. The crack is only about 20 kilometers away from reaching Larsen C’s edge and snapping off a Delaware-sized hunk of ice.

Such a breakup could destabilize the ice shelf — similar to the collapse of Larsen B in 2002, scientists with the project forecast in 2015 (SN: 7/25/15, p. 8). Because Larsen C’s ice is floating on the ocean, the breakup won’t directly raise sea levels. But with the ice shelf gone, more glacial ice could slip into the sea unabated and contribute to sea level rise.