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New Discovery Just Changed Our Understanding of The Source of Easter Island’s Moai

(Samir Belhamra/EyeEm/Getty Images)

PETER DOCKRILL


16 DEC 2019

For hundreds of years, they stood watch in silence: the ‘moai‘, a mysterious league of almost 1,000 carved monolithic statues, erected across the isolated landscape of Easter Island (Rapa Nui).

Just how these towering idols came to be has long fascinated researchers – as have the customs and collapse of the Polynesian society that engineered them – but the symbolic relevance of the figures themselves has never been fully understood.

Now, an international study offers fresh insights into what the moai could have represented to the islanders who toiled to quarry and carve the giant effigies.

010 moai sacred origins 1Excavation and analysis at the site of two moai in Rano Raraku as part of the study. (Easter Island Statue Project)

Over 90 percent of the moai statues were produced in a quarry called Rano Raraku: a volcanic crater that at its base makes up less than 1 percent of the island’s overall area, but nonetheless served as the single source of stone used to make the island’s megalithic sculptural objects.

Yet there’s more to Rano Raraku than just rock, the researchers say, based on an analysis of soil samples taken in the region.

“When we got the chemistry results back, I did a double take,” explains geoarchaeologist Sarah Sherwood from the University of the South in Sewanee, Tennessee.

“There were really high levels of things that I never would have thought would be there, such as calcium and phosphorous. The soil chemistry showed high levels of elements that are key to plant growth and essential for high yields.”

According to the research team, the established view of the quarry region is that it was an industrial site used to produce and temporarily store the moai prior to removal and transportation to other locations across the island.

Yet almost 400 of the monoliths remain in the quarry, and some are buried in the soil with support from fortified rock structures that suggest the placement is not temporary. The reason why, the researchers say, could be this uniquely rich soil.

“Everywhere else on the island the soil was being quickly worn out, eroding, being leeched of elements that feed plants,” Sherwood says.

“But in the quarry, with its constant new influx of small fragments of the bedrock generated by the quarrying process, there is a perfect feedback system of water, natural fertiliser and nutrients.”

In addition to evidence of the soil fertility, the researchers also found traces of ancient crops in the samples, including banana, taro, sweet potato, and paper mulberry.

These are all signs, the researchers think, that in addition to using the quarry for moai production, the Rapa Nui society also utilised the space as a place to grow foods they needed, leveraging the Rano Raraku’s rich, tilled soils, which would have produced higher yields with lower labour costs.

“We venture the novel suggestion that based on these data, and on the ritualisation of Rano Raraku and its stone as megalithic resources, Rano Raraku soil/sediment itself was a valuable and protected commodity,” the authors explain in their paper.

“Soil could have been transported from Rano Raraku to enrich those areas needing increased productivity.”

It’s a compelling case, but why were the moai also erected within the crater, amidst the land from which they were themselves produced?

It’s long been theorised that the ceremonial purpose of the monoliths was associated with fertility rituals, and the researchers say their fieldwork provides chemistry-based evidence of this link – not to mention the discovery of the carved pits, suggesting the moai were likely erected to stand watch over these verdant gardens indefinitely.

“This study radically alters the idea that all standing statues in Rano Raraku were simply awaiting transport out of the quarry,” says archaeologist Jo Anne Van Tilburg from UCLA.

“These and probably other upright moai in Rano Raraku were retained in place to ensure the sacred nature of the quarry itself. The moai were central to the idea of fertility, and in Rapa Nui belief their presence here stimulated agricultural food production.”

The findings are reported in the Journal of Archaeological Science.

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Science

Giant Panda Cubs Are Born Shockingly Small – Turns Out They’re ‘Undercooked’

MICHELLE STARR


16 DEC 2019

When giant pandas are born, they are not giant. In fact, they are almost comically small compared to their mums. Now, new research on baby panda skeletons has revealed that in almost any other mammal, the developmental stage of panda cubs when they’re born would be considered premature.

In short, giant panda bears are born at a stage of gestation that we’d think of as the beginning of the third trimester, if they were human babies.

At around 90 to 130 grams (3.2 to 4.6 ounces), newborn pandas are around the same size as a domestic cat’s kittens – not at all what you’d expect from a bear that tips the scales at 120 kilograms (220 pounds).

The birth weight of the giant panda (Ailuropoda melanoleuca) has long baffled biologists. The bears are born pink, squeaking and blind, still looking like a foetus, and extremely small – the mass ratio of the cub to mother hovers around 1:900. That’s the lowest birth weight ratio of all placental mammals, since most mammals are closer to 1:26.

In fact, all bears (family Ursidae) have unusually small cubs, but the giant pandas are particularly pronounced. This phenomenon is normally only seen in monotremes and marsupials, which give birth to positively lilliputian babies – and then nurse them intensively, usually in a maternal pouch, until they have finished baking.

But pandas and other bears don’t have pouches. So biologists Peishu Li  and Kathleen Smith of Duke University decided to study the skeletons of giant panda cubs to find out what gives.

Captive breeding of the ecologically vulnerable giant panda has been a tricky thing to master, and any cubs resulting from these programs are given the best care possible, so the skeletal remains of panda cubs are not easily obtained.

But, in the 1980s, five cubs were born to giant pandas Ling-Ling and Hsing-Hsing at the Smithsonian’s National Zoo that, sadly, did not survive long after birth. Their skeletons were preserved, so Li and Smith were able to take micro-CT scans of two of them.

They also took scans of some other mammals’ newborns – grizzly bears (Ursus arctos), sloth bears (Melursus ursinus), polar bears (U. maritimus), a red panda (Ailurus fulgens), a coati (Nasua narica), an African wild dog (Lycaon pictus), an arctic fox (Vulpes lagopus) and two domestic dogs (Canis familiaris), one of which was foetal.

They created 3D models of all the skeletons, and carefully studied them to see how developed they were – the level of ossification, or bone growth; whether the teeth had started to form or erupt; and the fusion of the plates of the skull.

One hypothesis about the low birth weight of bears involves hibernation; the idea goes that if the pregnancy overlaps with hibernation, that period of fasting could result in an earlier birth when the mother’s internal reserves grow low.

Not all bears hibernate – giant pandas don’t, for instance – but, scientists have argued that over the course of evolution, low birth weight could have become a feature of bears in general.

But in this study, when the biologists examined and compared all the skeletons, they found that, overall, the skeletons of newborn bears were just as developed as the skeletons of the other newborn animals. This would suggest that bear cubs are born full term.

With one exception. The giant panda cubs. Their bones resembled those of the puppy foetus, delivered several weeks before it was due, at around 70 percent of its gestation period.

“That would be like a 28-week human fetus,” Smith said. (The human gestation period is 40 weeks.)

The giant panda’s gestation period is 97 to 161 days, which seems like a long time, considering how tiny the cubs are. Previous studies have shown that’s because of delayed implantation, in which the embryo floats around in the womb for a few months before attaching to the wall of the uterus; it will only start developing after this attachment.

This is common in bears, and it may have something to do with food availability. But in pandas, the period of gestation after attachment is much shorter than other bears. They follow the same development trajectory as other mammals, but they pop out before they’re done.

“They’re basically undercooked,” Li said.

The reason for this? Well, we still don’t know. What we do know is that the size of adult bears has increased in the last 20 million years; perhaps while the bears grew, the birth weight of their cubs did not.

“Given its close phylogenetic affinity with other ursine bears and adaptations to an herbivorous diet like the giant panda, the cave bear may be a promising candidate to further shed light upon the relationship between phylogeny, herbivory and reproductive physiology among Ursidae,” the researchers conclude in their paper.

The research has been published in the Journal of Anatomy.

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Science

Ever Heard of ‘Hair Ice’? It’s Totally a Thing

CARLY CASSELLA


16 DEC 2019

Walking through a wintry broadleaf forest in the cold morning light, you might be lucky enough to spot a fleeting enigma called “hair ice”.

At first, it might look as though the rotten branch of a tree has grown a shiny white toupee, or perhaps a delicious bunch of cotton candy.

But when you rub the wispy strands between your fingers, you’ll find they are cold, ephemeral, and nothing like hair at all.

Found tons of “hair ice” out in Olympic National Forest near Sequim this morning!

“This is some Annihilation shit” pic.twitter.com/4K9VvLnIVM

— Jake Buehler (@buehlersciwri) December 15, 2019

This is the ice wool of the forest, the frost beard of the trees, and it’s such a strange sight, it continues to fascinate humans whenever we’re lucky to come across it.

Described for the first time almost one hundred years ago, this unusual icy structure was thought to come from fungus, although it was only in 2015 that scientists finally confirmed the species responsible for it.

Growing under the cover of darkness in the humid winter, usually between the latitudes of 45 and 55 degrees north, the phenomenon can quickly disappear under the equally white snow and the watchful eye of the sun.

While it’s commonly called a ‘frost’, that’s not technically correct. Ice crystals are formed at below-freezing temperatures, but they are later ‘sculpted’ into fine strands of hair by a resident fungus known as Exidiopsis effusa.

Exactly how it manages this is still a mystery, but scientists think it might have to do with a ‘recrystallisation inhibitor’ provided by the fungus.

FrostBeardDetail 1(Kostian/Wikimedia Commons/Public Domain)

“The same amount of ice is produced on wood with or without fungal activity, but without this activity the ice forms a crust-like structure,” explained physicist Christian Mätzler, who co-wrote the paper on the origins of hair ice in 2015.

“The action of the fungus is to enable the ice to form thin hairs – with a diameter of about 0.01 millimetres – and to keep this shape over many hours at temperatures close to 0°C.”

Wood can get covered in such ice through a process called ‘ice segregation’, when water sitting near the surface of the branch collides with cold air, thereby smooshing the liquid into a thin film of ice, which then squeezes through the pores of wood and freezes on top of each other.

As the ice builds up, stacking one crystal on another, it does something strange. Instead of forming into large ice crystals on the surface of the wood, the strands remain separated and ultra thin, as the video below shows.

Growing up to 20 centimetres (nearly 8 inches) in length, these fine silvery fibres are about the same thickness as human hair.

Chemical analyses from 2015 suggest that as E. effusa breaks down the wood, it produces complex molecules like lignin and tannin, which can mix with liquid water and stop the ice strands from bunching up into more stable shapes.

“These components may be the ones preventing the formation of large ice crystals at the wood surface,” said chemist Diana Hofmann, who also worked on the 2015 paper.

More research will be needed before this hunch can be confirmed, and there are plenty of other questions left unanswered. For instance, whereabouts in the world does hair ice form? Why does it only grow on certain trees and plant species? And are there any other strange ice forms that haven’t yet been discovered?

“People have seen hair ice and similar forms of ice in nature for centuries,” ice specialist James Carter, who was not involved in the study, told Earth Magazine back in 2015.

“Now that we have the Internet and digital cameras, people are able to share their findings, and we are able to see many examples of these forms of ice.”

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Science

Strange Sun Effects Have Been Detected by World’s Highest Weather Stations on Everest

(Adisorn Fineday Chutikunakorn/Getty Images/Moment)

MADDIE STONE, THE WASHINGTON POST


16 DEC 2019

Data from a network of newly installed weather stations atop Mount Everest shows that the mountain experiences some of the most intense sunlight on the planet.

As alpine mountaineers are all too aware, the sun can be brutally fierce atop snow-capped peaks.

Preliminary data from the weather stations on Mount Everest suggests this effect is amplified to an astounding degree at the top of the world, creating what could be some of the most intense illumination anywhere on Earth’s surface.

This epic lighting does more than give hikers nasty sunburns. In a warming world, it might be hastening ice melt atop the world’s highest mountains and impacting glaciers in ways scientists do not fully understand.

Presented at the American Geophysical Union annual meeting in San Francisco on Friday, the data is among the first scientific results to emerge from the National Geographic Society’s and Rolex’s Perpetual Planet Extreme Expedition to Everest, a multidisciplinary effort to study climate change atop the world’s tallest mountain.

As part of the field excursion last spring, researchers installed a network of five automatic weather stations at elevations of up to 27,600 feet (8,412 meters), which includes the two highest weather stations on the planet.

These stations are helping to fill a critical gap in our understanding of high alpine meteorology and climate: Before their installation, the highest operating weather station the researchers knew of sat atop nearby Mera Peak, at a paltry altitude of about 21,000 feet (6,400 meters).

“There’s still a lot of ice in the Himalayas above that altitude,” said Tom Matthews, a climate scientist at Loughborough University in Britain and the meteorology co-lead for the expedition. “It’s a monumental data gap.”

All five stations are collecting data on air temperature, pressure, relative humidity and wind speed. Every station except for the highest one is outfitted with a net radiometer, an instrument that measures incoming and outgoing radiation, and the lower stations also carry rain gauges and present weather sensors.

Every day, the solar-powered stations beam their data via satellite links so that it can be uploaded in near-real time to the National Geographic Society’s Perpetual Planet website. As of this week, the data is also being shared on social media by an Everest weather Twitter bot.

One of the key motivations behind the weather-station network is to better understand the amount of energy available to melt snow and ice in high alpine environments.

As Matthews explained, the highest Himalayan peaks get incredibly sunny both because there is less atmosphere to attenuate the light and because of their near-equatorial latitude.

While Everest hikers experience this viscerally, becoming overheated when the air temperature is close to freezing, solar radiation often is not accounted for when scientists model ice loss, Matthews said. Without available data, scientists may assume ice melt is driven solely by the air temperature.

But early returns from the new weather-station network suggest the sun is a truly dazzling force atop Everest, and its ice-melting power needs to be considered.

In some cases, Matthews said, the stations have registered levels of solar radiation equal to or exceeding the solar constant – that is, the amount of sunlight scientists expect to see at the outermost limits of Earth’s atmosphere.

The researchers suspect this unearthly luminescence is the result of sunlight getting ping-ponged around by snow and ice as it falls on Everest’s frozen spires.

“It’s like a microwave, basically,” Matthews said.

The data has not yet been published in a peer-reviewed journal. But if the findings hold up, Matthews says it could mean there is significant melt occurring hundreds of feet above the point where air temperatures drop below freezing.

Extrapolated across High Mountain Asia, “there could be thousands of square kilometers experiencing melt that we didn’t know about,” he said.

It is helpful to have more direct observations of weather at these extreme elevations, said Surendra Adhikari, an Earth scientist at NASA’s Jet Propulsion Laboratory who was not involved in the new research.

While scientists have long understood that solar heating plays a role in glacial melting and that the effect increases with altitude, “we don’t have a good idea of the size of that amplification,” he said.

At very high altitudes, much of the meltwater produced by the sun is likely refreezing in place as it percolates into the snow. But that it still an important process to account for, said Joseph Shea, an alpine scientist with the University of Northern British Columbia Faculty Association who also was not involved in the analysis.

As this water refreezes, it releases heat energy and fills in air pockets, causing the surrounding snow and ice to become warmer and denser.

This may be impacting the long-term evolution of alpine glaciers in ways that are not being captured by models.

“If you’re modeling melt, you want to account for all of these energy influxes,” Shea said. “It’s really hard to do when we don’t have data.”

Sorting out the various processes driving ice loss in the Himalayas has never been more urgent. These glaciers, whose water nourishes lands home to over a billion people, are receding at an alarming rate as global temperatures rise.

The region is often referred to as the “Third Pole”, because of the huge volume of ice present there.

A groundbreaking report published earlier this year concluded that glaciers across the Hindu Kush Himalayan region could shrink in size by a third even if the ambitious 1.5-degree Celsius (2.7 degrees) global warming target is reached.

In addition to sunlight, the weather station data will provide critical insight into how much and when precipitation is falling on the mountains, as well as the role of the Asian monsoon, which is also affected by climate change.

With a few years’ worth of data, Matthews and his colleagues are hoping to be able to say more about how the timing and intensity of monsoon precipitation impacts Earth’s highest glaciers.

Before any of that can happen, however, the weather stations will face their biggest test yet: a winter atop Mount Everest. Matthews said he expects to see temperatures at the higher stations plunge below minus-40 degrees in the coming weeks and months.

Because the depths of winter also bring the fiercest winds of the year, a new world record wind chill “is on the cards,” he said.

The weather stations are drilled into the bedrock and rated to withstand winds of nearly 240 mph (386 km/h). There is a small concern that there could be faster winds at such lofty heights, but the main worry is wind blowing rocks that would disable critical instrumentation or a solar panel.

“The big concern is really strong winds that do things to the station we can’t plan for,” Matthews said.

So far, all stations are holding up well. “The sensors seem to be functioning fine,” he said. “But this is the moment of truth season.”

2019 © The Washington Post

This article was originally published by The Washington Post.

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Science

Your Constant Feeling of ‘Being Tired’ Could Be Due to a Serious Health Problem

EMILY SOHN, THE WASHINGTON POST


16 DEC 2019

Tired? Join the club.

Feeling tired or fatigued is a common experience. Yet health-care providers often dismiss complaints about tiredness – both because the symptom is universal and because it can be challenging to evaluate medically, says Michael Grandner, director of the University of Arizona’s Sleep & Health Research Program in Tucson.

And while tiredness is often temporary, treatable or nothing to worry about, experts say that tiredness that suddenly worsens or prevents you from doing what you want can be a sign of a health problem or sleep disorder.

“Sleep seems to be a canary in the coal mine, where it’s sensitive to all these things going on in your body,” Grandner says.

“So, when it starts changing, you want to ask, ‘Well, what’s going on?'”

Sleepiness, fatigue, tiredness: in conversation, people use the terms interchangeably. But medically, their definitions differ. Understanding the differences is an important first step toward tackling the problem – or figuring out if there is one.

Sleepiness is a need for sleep that makes it difficult to stay awake, even while driving, working or watching a movie, and even after ingesting caffeine.

Fatigue, on the other hand, is a deeper sort of an inability, either physical or mental, to do what you want to do, such as get to the grocery store.

Somewhere in the middle is tiredness, a desire to rest that is less debilitating than fatigue and less dramatic than sleepiness. You can still be productive while tired.

Whatever you call it, it’s common. In a 2014 survey by the nonprofit National Sleep Foundation, 45 percent of adults said they had been affected by poor sleep or not enough sleep in the previous week.

As many as 20 percent of people report excessive sleepiness on a regular basis. And, a National Safety Council survey reported in 2017 that 76 percent of people felt tired at work.

If you’re bothered by how tired you feel, there might be some simple explanations, including the most basic: not enough sleep. A third of Americans don’t get the recommended seven or more hours a night, according to the Centers for Disease Control and Prevention. And because needs vary widely, even seven hours isn’t enough for many people.

“If you’re routinely getting five or six hours of sleep and you’re feeling tired,” Grandner says, “that’s an easy thing to check off the list in terms of figuring out what the problem is.”

Sleep deprivation is not just a nuisance. It raises the risk for car accidents and has been linked with health concerns such as Type 2 diabetes, cardiovascular disease and depression.

Lack of sleep can also affect mood and relationships in ways that even caffeine can’t remedy, says Nathaniel Watson, director of the Harborview Sleep Clinic at the University of Washington in Seattle. “There is no substitute for sleep,” he says.

Beware the temptation to lie down exactly seven hours before your alarm is set to go off. Nobody sleeps 100 percent of the time that they’re in bed, Watson says, so it might take eight hours of pillow time to get seven hours of sleep.

The physiology of sleep might also be getting in your way, if only temporarily. A phenomenon called sleep inertia, for example, is what helps you fall back asleep after ordinary night wakings, which typically happen multiple times a night, Grandner says.

But sleep inertia will also make it tough to get up in the morning if the alarm rings during a deep stage of sleep. That grogginess should wear off within half an hour of pushing through it.

Also normal are occasional rough nights because of stress or sleep interruptions. And even if you get a good night’s rest, you may experience a mid-afternoon bout of sleepiness as a result of ordinary circadian rhythms.

Age is something else to keep in mind, though the evidence there is somewhat counterintuitive. Studies show that, as people get older, sleep patterns tend to change in predictable ways. It may start taking longer to fall asleep. You may wake up more often and spend more time awake in the night. And bedtimes and mornings may shift earlier. Menopause is another common cause of interrupted sleep.

But sleep satisfaction doesn’t necessarily drop with age. Studies by Grandner and others have found that complaints about sleep and tiredness actually decline with age after a peak in early adulthood. In other words, you should not blame aging if you find yourself struggling with tiredness.

“Aging is associated with sleep that is a little shallower and a little more broken up, but not less satisfying,” Grandner says. “If you’re an older person and you’re really unhappy with your sleep, that’s actually an issue.”

For people of any age, if tiredness is making it hard for you to get through most days or otherwise getting in your way, experts suggest visiting a primary-care clinic first to be evaluated for common causes of fatigue or tiredness, including depression, autoimmune diseases, vitamin levels and thyroid issues.

One warning: The appointment might be frustrating. Many doctors lack training in sleep medicine, Watson says. Primary-care physicians don’t routinely ask patients about sleep, Grandner adds.

They also often miss the signs of insomnia or they suggest ineffective treatments for it, a 2017 study found. Insomnia affects up to 15 percent of adults and, Grandner says, studies show that behavioral therapies work better than medication.

A friend of mine, a parent of a young child, told me that her doctor laughed at her when she mentioned she was tired all the time, as though that was a given at her stage in life.

Anecdotally, though, doctors’ visits can turn up all sorts of conditions. Friends have told me about tiredness that led to diagnoses of iron deficiency, fibromyalgia, celiac disease, encephalitis and more.

If nothing turns up in the regular clinic, it’s worth seeing a sleep specialist, whose evaluation is likely to include screening for sleep apnea. The disorder, which causes people to periodically stop breathing in their sleep, affects up to 10 percent of adults – with rates higher for people who are overweight. Most don’t know they have it. About 85 percent of people who have sleep apnea are undiagnosed and untreated, Watson says.

Bottom line, experts say: Being tired is worth paying attention to. The good news is that causes are often treatable.

“If you’re feeling sleepy and it’s interfering with your life, you shouldn’t just think this is normal kind of a thing,” Watson says. “We need to realize that if we prioritize sleep, we become the best version of ourselves.”

2019 © The Washington Post

This article was originally published by The Washington Post.