The image above, “A Sunday Afternoon on the Island of La Grande Jatte,” was painted in 1884 by French artist Georges Seurat. The black lines crisscrossing it are not the work of a toddler wreaking havoc with a permanent marker, but that of neuroscientist Robert Wurtz of the National Eye Institute in the US. Ten years ago, he asked a colleague to look at the painting while wearing a contact lens–like contraption that recorded the colleague’s eye movements. These were then translated into the graffiti you see here.
Art lovers may cringe, yet it is likely that Seurat would have been intrigued by this augmentation of his work. The movement Seurat kick-started with this painting — Neo-Impressionism — drew inspiration from the scientific study of how our vision works. Particularly influential was the pioneering research of Hermann von Helmholtz, a German physician, physicist and philosopher and author of a seminal 1867 book, Handbook of Physiological Optics, on the way we perceive depth, color and motion.Read More
When it comes to medical diagnoses, Alzheimer’s is a grim one. Those who develop the disease, which causes ever-worsening memory and behavioral problems, don’t have many treatment options. There are a handful of drugs that can ease symptoms, but none of them slow down the disease’s progression or offer a cure. But one approach, outside the realm of drugs and medications, is quickly showing some strong potential for treatment — fasting.
Typically touted as a weight loss method, fasting has been shown in animal studies to help improve the symptoms of Alzheimer’s disease and slow cognitive decline in mice. Research on the link between diet and brain health is now moving to humans, with some researchers hoping that fasting could one day be used to treat and prevent a debilitating disease.
Alzheimer’s disease is quite common among older adults: an estimated 5.8 million Americans live with it today. The disease manifests itself as memory loss, changes in behavior and problems thinking. These changes are mirrored internally by the degradation of parts of the brain responsible for memory. In Alzheimer’s patients, scientists have long known that harmful collections of proteins between nerve cells, called plaques, as well as proteins inside nerve cells, called tangles, start to accumulate. These plaques and tangles wreak havoc on the brain, killing cells and disrupting normal brain functions as they spread. What exactly causes these plaques and tangles to develop, and why people with them get Alzheimer’s disease, is still up in the air.
But Mark Mattson, a recently-retired professor of neuroscience at John Hopkins University, thinks it has something to do with our modern eating habits — particularly, the timing of our meals.
Mattson has spent decades researching calorie intake and Alzheimer’s disease. In several studies of mice genetically altered to display symptoms of Alzheimer’s he’s found that those fed intermittent fasting diets — where you cycle through short periods of eating and longer periods of fasting — fared better than those who ate whenever they wanted. They had better cognitive function, lived longer and, most importantly, had less plaque build up in their brains.
Mattson thinks that the positive effects seen in mice — whose brains are similar to humans — could be rooted in evolution. Before the rise in agriculture, when people were still hunting for food, they often went long periods without eating. Over time, evolution favored those who could survive without their beloved breakfasts (and lunches and dinners).
We now know that we use the glucose we get from foods, particularly carbohydrates, to fuel our bodies. We use this fuel, called glycogen, for about 12 hours after we eat. When it runs out, our bodies switch to an alternate energy source — ketone bodies.
Produced by the liver during periods of fasting and low carbohydrate intake, ketones also fuel our organs, including the brain. In the brain, much of this energy goes to our neurons. But while both glycogen and ketones fuel our neurons, higher ketone production has been linked to improved thinking, learning and memory. Some scientists theorize that ketones provide neurons with more energy than glycogen does, and with this extra energy, the neurons can better ward off cell death and brain degradation in the long term.
But with early breakfasts and late-night snacking, the standard American diet prevents us from making that metabolic switch from glycogen to ketones. According to Mattson, we could be starving our brains of the fuel they need to live a long, healthy life.
To see if this theory holds true, Mattson is now wrapping up a study in people at high risk for Alzheimer’s — those between the ages of 55 and 70 and who are obese and insulin resistant. The participants were put on a 5:2 fasting diet, where they eat five days out of the week and fast for two. Their cognitive performance and brain activity were tested both before and after implementing the diet. By triggering that metabolic switch, Mattson will be able to note any improvements in brain health and cognitive function. And while the results have yet to be released, Mattson says that his preliminary work indicates clear benefits for those on the intermittent fasting diet.
Valter Longo, a professor of biological sciences at the University of Southern California, has also spent decades studying the link between aging and fasting. And like Mattson, he’s seen slower cognitive decline and increased longevity in mice on fasting diets. Longo similarly thinks that the metabolic switch from glucose to ketone bodies plays a major role in brain health and longevity, and is currently undertaking tests in humans.
Longo recently kicked off a study of 120 patients who have been diagnosed with either Alzheimer’s disease or mild cognitive impairment. He’s using a variation of a fasting diet that’s less drastic, though it mimics the essential effects.
The method was designed with elderly patients in mind, who might not be strong enough to do prolonged fasts every day. Instead, patients do five days of fasting each month while consuming small amounts of healthy fats each day. By eating fats and no carbohydrates during that time, their bodies will keep using ketones instead of glucose as fuel.
It’s an attempt to split the difference: participants will still be able to get nutrients from food while reaping the potential brain-saving benefits of fasting.
While Longo and Mattson’s studies could start backing up theories about Alzeimer’s and fasting with evidence, we’re still a long way from drawing any official conclusions. With other factors like exercise, sleep, stress and diabetes also being linked to the disease, untangling the mystery of Alzheimer’s is far from over.
For now, and until we know more about the disease, Longo says that limiting calorie intake to about 12 hours a day could be a good way to help brain health. So for now, you might want to think twice about that nighttime snack. Your brain might thank you later.
Have you ever spaced out during a meeting, but been jolted back to reality by the sound of your boss calling your name a few times? If you’ve ever been in this awkward situation, you might have experienced “microsleep.”
This weird state of consciousness is characterized by brief bursts of sleep that happen while a person is awake — often while their eyes are open and they’re either sitting upright, or even performing a task. During microsleep, parts of the brain go offline for a few seconds while the rest of the brain stays awake. It’s sort of like being a zombie for a few brief moments — sans the whole “eating human flesh” part. And usually, people don’t realize it’s happening to them.
Researchers don’t fully understand why certain parts of our brain switch off throughout the day. But they have found the states of sleep and wakefulness aren’t as cut and dry as we might assume. And although fatigue does seem to prime the brain for microsleep, even well-rested people do it — a lot.Read More
The first time someone synthesized saccharin, the artificial sweetener in Sweet’N Low, it was an accident. A scientist studying coal tar in 1879 didn’t wash his hands before eating dinner and was surprised to taste a sweet residue from the lab on his fingertips. Same goes for the invention of the sweetener sodium cyclamate in 1937: the unwitting pioneer, who was working on a fever medication, put his cigarette down on the lab bench, and when he picked it back up, he detected something sweet. Both products went on be included in sweetener packets and diet soda the world over. The takeaway: The search for a viable sugar alternative is no modern undertaking (and also, some chemists should probably brush up on their laboratory safety skills).Read More
SpaceX’s ambitious Starlink project could eventually launch more than 10,000 satellites into orbit and rewrite the future of the internet. But Elon Musk’s company has been taking heat from the astronomical community after an initial launch in late May released the first 60 satellites. The 500 pound (227 kg) satellites were clearly visible in Earth’s night sky, inspiring concern that they could increase light pollution, interfere with radio signals, and contribute to the growing issue of space debris.
This week, the American Astronomical Society, the International Astronomical Union, the British Royal Astronomical Society, and the International Dark-Sky Association (IDA) all issued statements expressing concern about Starlink’s potential to damage astronomical research by leaving bright streaks through images.
“The Starlink affair has raised the attention of the astronomy community in a way that I’ve not seen during my couple of decades in it,” says John Barentine, director of public policy at the IDA, which lobbies against light pollution. “I hope that this moment is the wake-up call that is needed to prompt a new discussion in the international community about the nature of outer space, especially near the Earth, in a commercial context.”
Musk had repeatedly assured people on Twitter that his satellites wouldn’t be visible at night, so the light caught some people by surprise. However, the satellites’ initial brightness is intended to wane as they climb higher into their permanent orbits.
“The observability of the Starlink satellites is dramatically reduced as they raise orbit to greater distance and orient themselves with the phased array antennas toward Earth and their solar arrays behind the body of the satellite,” a spokesperson for SpaceX said in an email.
But Barentine and other astronomers aren’t so sure, especially given that this is only the beginning for Starlink. Plus, many other companies — including Amazon, Boeing, OneWeb, Telesat, LeoSat, and even Facebook — are planning other so-called “mega-constellations” for connecting the masses online.
“There are billions of people around the world who lack access to broadband internet,” a spokesperson for Amazon’s Project Kuiper said in an email. “Our vision is to provide low-latency, high-speed broadband connectivity to many of these unserved and underserved communities around the world … Many of our satellite and mission design decisions are, and will continue to be, driven by our goals of ensuring space safety and taking into account concerns about light pollution.”
But there are already 22,000 artificial objects currently in orbit. And as the microlaunch space race kicks into high gear, that number is destined to double. Communications satellites aren’t the only things headed up, either. One group even proposed launching orbiting billboards that would shine ads back down to Earth. And an artist recently launched the “Humanity Star” – a purely artistic light beacon.
“Space is already crowded, and roughly doubling the number of objects in low- and near-Earth orbit will only add to the visual pollution of the night sky,” Barentine says. “Being in a dark place and seeing one satellite fly over every few minutes is one thing. But seeing literally dozens of them at any given time for hours every night is another story entirely.”
Part of the reason this problem stands to get worse, according to astrophysicist Laura Forczyk, is “there is no regulatory body in the United States that directs companies as to the kind of light pollution or the brightness of satellites. This is a fairly new topic and as always the government regulations are behind technology.”
But Forczyk, owner of the space consulting firm Astralytical, also says that changing the night skies isn’t the same thing as losing the night sky — and it’s a little too early to know what the total impact is going to be. After all, the Starlink satellites still haven’t reached their final orbit. “We’re very reactive when it comes to these kinds of things,” she says, but emphasizes miscommunication from both sides.
Whether the problem stands to worsen or not, most experts see the growth of these mega-constellations as inevitable.
“I don’t think we’re going to be able to create political will to stop the satellites because there is so much commercial potential and politicians tend to respond to economics,” says Phil Metzger, a planetary scientist at the University of Central Florida and a former NASA physicist. However, he says future designs of satellites can ensure they’ll cause less interference with on-the-ground astronomy.
“We can change the surface of the spacecraft so it is more absorptive and less reflective or we can even make it more transparent,” Metzger says. “We do have the ability to make electrical conductors completely transparent so we don’t need metal. You could have glass with transparent conductors in the glass … I think we’ll probably be doing all of these things in the future.”
Two trophy skulls, recently discovered by archaeologists in the jungles of Belize, may help shed light on the little-understood collapse of the once powerful Classic Maya civilization.
The defleshed and painted human skulls, meant to be worn around the neck as pendants, were buried with a warrior over a thousand years ago at Pacbitun, a Maya city. They likely represent gruesome symbols of military might: war trophies made from the heads of defeated foes.
Both skulls are similar to depictions of trophy skulls worn by victorious soldiers in stone carvings and on painted ceramic vessels from other Maya sites.
Drilled holes likely held feathers, leather straps or both. Other holes served to anchor the jaws in place and suspend the cranium around the warrior’s neck, while the backs were sawed off to make the skulls lie flat on the wearer’s chest.
Flecks of red paint decorate one of the jaws. It’s carved with glyphic writing that includes what my collaborator Christophe Helmke, an expert on Maya writing, believes is the first known instance of the Maya term for “trophy skull.”
What do these skulls — where they were found and who they were from — tell us about the end of a powerful political system that thrived for centuries, covering southeastern Mexico, all of Guatemala and Belize, and portions of Honduras and El Salvador? My colleagues and I are thinking about them as clues to understanding this tumultuous period.
The vast Maya empire flourished throughout Central America, with the first major cities appearing between 750 and 500 B.C. But beginning in the southern lowlands of Guatemala, Belize and Honduras in the eighth century A.D., people abandoned major Maya cities throughout the region. Archaeologists are fascinated by the mystery of what we call “the collapse” of this once powerful empire.
Earlier studies focused on identifying a single cause of the collapse. Could it have been environmental degradation resulting from the increasing demands of overpopulated cities? Warfare? Loss of faith in leaders? Drought?
All of these certainly took place, but none on its own fully explains what researchers know about the collapse that gradually swept through the landscape over the course of a century and a half. Today, archaeologists acknowledge the complexity of what happened.
Clearly violence and warfare contributed to the end of some southern lowland cities, as evidenced by quickly constructed fortifications identified by aerial LiDAR surveys at a number of sites.
Trophy skulls, together with a growing list of scattered finds from other sites in Belize, Honduras and Mexico, provide intriguing evidence that the conflict may have been civil in nature, pitting rising powers in the north against the established dynasties in the south.
Ceramic vessels found alongside the Pacbitun warrior and his (or her – the bones were too fragmentary to confidently determine sex) trophy skull date to the eighth or ninth century, just prior to the site’s abandonment.
During this period, Pacbitun and other Maya cities in the southern lowlands were beginning their decline, while Maya political centers in the north, in what is now the Yucatan of Mexico, rose to dominance. But the exact timing and nature of this power transition remains uncertain.
In many of these northern cities, art from this period is notoriously militaristic, abounding with skulls and bones and often showing war captives being killed and decapitated.
At Pakal Na, another southern site in Belize, a similar trophy skull was discovered inscribed with fire and animal imagery resembling northern military symbolism, suggesting a northern origin of the warrior it was buried with. The presence of northern military paraphernalia in the form of these skulls may point to a loss of control by local leaders.
Archaeologist Patricia McAnany has argued that the presence of northerners in the river valleys of central Belize may be related to the lucrative trade of cacao, the plant from which chocolate is made. Cacao was an important ingredient in rituals, and a symbol of wealth and power of Maya elites. However, the geology of the northern Yucatan makes it difficult to grow cacao on a large scale, necessitating the establishment of a reliable supply source from elsewhere.
At the northern site of Xuenkal, Mexico, Vera Tiesler and colleagues used strontium isotopes to pinpoint the geographic origin of a warrior and his trophy skull. He was local from the north. But the trophy skull he brought home, found atop his chest in burial, was from an individual who grew up in the south.
Other evidence at a number of sites in the southern highlands seems to mark a sudden and violent end for the community’s ruling order. Archaeologists have found evidence for the execution of one ruling family and desecration of sacred sites and elite tombs. At the regional capital site of Tipan Chen Uitz, approximately 20 miles (30 kilometers) east of Pacbitun, my colleagues and I found remains of several carved stone monuments that seem to have been intentionally smashed and strewn across the front of the main ceremonial pyramid.
Archaeologists are not only interested in identifying the timing and the social and environmental factors associated with collapse, which vary in different regions. We’re also trying to figure out how specific communities and their leaders responded to the unique combinations of these stresses they faced.
While the evidence from just a handful of trophy skulls does not conclusively show that sites in parts of the southern lowlands were being overrun by northern warriors, it does at least point to the role of violence and, potentially, warfare as contributing to the end of the established political order in central Belize.
These grisly artifacts lend an intriguing element to the sweep of events that resulted in the end of one of the richest, most sophisticated, scientifically advanced cultures of its time.
Every spring, farmers across the Midwest take to the fields to plant their crops. Here, corn and soybeans will reign supreme over tens of millions of acres, as soon as conditions are right to plant. Not too wet, not too dry – just right.
But the U.S. had an exceptionally wet winter this year. And it kept raining in the spring. April turned to May, and it kept raining. May turned to June, and, well, you get the picture. The past 12 months in the U.S. have been the wettest on record.Read More
Worldwide, people drink over 65 billion gallons of alcohol each year. The United States’ share, if divided equally across the adult population, would amount to about two and a half gallons of pure alcohol per person, annually. And this thirst seems to be universal: Fermented beverages have been found in nearly every society, as far back as archaeologists can detect their existence.
That’s the idea behind the “drunken monkey” hypothesis, formulated by biologist Robert Dudley in 2000.
According to the hypothesis, our pre-human ancestors regularly ingested small amounts of alcohol because the substance is produced when ripe fruit or nectar is decomposed by wild yeast. Through natural fermentation, yeast feeds on plant sugars and produces waste products of CO2 and ethanol — the chemical name for alcohol.Read More
Many marathon runners know the boost that can come from popping a mid-race energy gel. (Mmmm, calorie-rich goop.) But according to new research published in Science Advances, when it comes to endurance events, there’s a limit to how much energy the human body can draw from breaking down, or metabolizing, food. That metabolic limit depends on how long whatever tortu… — err, event you’re enduring lasts. But importantly, after a certain point in time, it plateaus, suggesting humans have a universal cap for how much energy their bodies can absorb.Read More
Before the brewpub there was the brew cave.
In Israel’s Raqefet Cave archaeologists recently reported traces of what could be the earliest known beer production 13,000 years ago.
The evidence comes from three stone mortars, analyzed in a 2018 Journal of Archaeological Science: Reports paper. After extracting residues from the rocks, the researchers identified plant molecules, including wheat or barley starches that appeared malted, mashed and fermented — the main ingredients and basic steps of beer brewing. The team also analyzed microscopic scratches and polishing on the stones. Two of the mortars had patterns indicative of plant storage and the other seems to have been used for pounding food with a wooden pestle.
If the interpretation is correct, this would push evidence for alcohol production or fermentation back several millennia. In 2012 researchers found “not fully conclusive” chemical traces of beer production in ~10,000-year-old limestone basins at the site of Göbekli Tepe, Turkey. Analysis of those vats is ongoing. But convincing booze dates to roughly 8,000 years ago, as attested by chemical markers in pottery from both China and the Caucasus mountains in the Middle East, between the Black and Caspian Seas. The preserved molecules suggest the Chinese were fermenting a brew of rice, honey and fruit, while the Middle Easterners were making grape wine.
Though the list of possible ingredients is long, scholars classify alcoholic beverages into beer —made from starches that must be broken into sugars before fermentation — and wine, which is made from sugars like fruit or honey that can be directly fermented. During fermentation, certain microbes, particularly yeasts of the Saccharomyces type, feed on the sugar, producing CO2 and ethanol, or drinkable alcohol. Hard liquor like whiskey or vodka requires the additional step of distillation, using evaporation to purify the ethanol into a higher concentration. The origins of this process are unclear, but ancient Greeks and Arabs distilled alcohol originally for medicine and perfume. Drinking spirits seems to have become popular in 16th century Europe.
Raqefet Cave seems like an odd spot for a brewery 13,000 years ago. On a steep hillside about 10 miles from the Mediterranean, the cave at this time was used as a cemetery, containing the remains of at least 29 men, women and children. The researchers suggest the beer remnants found there may have come from funerary rituals to venerate the dead.
Furthermore, these ancient brewers must have relied on wild cereals, because wheat and barley were not domesticated in the Near East until several thousand years later.
But some scholars don’t find this surprising. In fact, archaeologists have long entertained the possibility that cereals were made into beer long before they were farmed for food. A scholarly debate in 1953 asked “Did Man Once Live by Beer Alone?” and suggested that selectively picking plants for beer led to the origins of agriculture in the Near East “cradle of civilization.”
At that time the debate was speculative, because tangible traces of alcohol use could not be seen in the archaeological record. Yes, modern booze has a long shelf life, but bulk alcohol has not survived since the dawn of civilization.
Our ability to detect ancient alcohol changed in recent decades, as scientists developed tools to recover microscopic plant remains and biomolecules from artifacts and fossils. In recent years we’ve found traces of alcohol or its raw ingredients from numerous archaeological cultures, including wine in ancient Armenia ~6000 years ago, Nordic grog made from honey, fruit and cereals from ~1500 BC and corn beer from the Lake Titicaca region in the South American Andes from ~800 BC.
The diversity of ages and regions make clear that alcohol was independently discovered in many societies across the world, using native plants and technology. In different cultures, alcohol was imbibed as a source of nutrition, during rituals and for merrymaking, just as it is today.
By combining results from molecular analyses with ancient texts, artistic depictions and traditional recipes for alcohol, researchers have reconstructed many ancient brews.
In the Inca Empire of the Andes, the main alcoholic drink was corn beer of usually less than 5 percent ABV, called chicha in Spanish or aqa in native Quechua. The Aztecs of Mesoamerica made pulque from agave juice, also at around 5 percent ABV. In ancient Mesopotamia and Egypt, barley and emmer wheat beer of 3 to 6 percent was consumed daily at meals, and was likely a major source of nutritional calories, while wine of 8 to 14 percent was consumed by elites or on special occasions. Sub-Saharan Africa has traditional alcoholic beverages, still consumed today, made from cereals, bananas, palm sap and honey, though less is known about their origins.
And the ancient ABV award probably goes to East and South Asia where, since before written history, rice-based drinks like Japanese sake likely hit 10 to 20 percent.