Indholdsfortegnelse for January - February 2016 i Discover

It’s here — our giant-size Year in Science issue, featuring the top 100 science stories from 2015, plus our fiery Image of the Year. As usual, we’re devoting all of our pages to those stories, but don’t worry: Your favorite columns will return next time. Meanwhile, enjoy the issue and be sure to visit DiscoverMagazine.com/YearInScience for bonus coverage of our top 100 stories and much more. CONNECT WITH US facebook.com/DiscoverMag twitter.com/DiscoverMag plus.google.com/+discovermagazine…

The sun’s surface is hot, sure — almost 10,000 degrees Fahrenheit — but the solar atmosphere, or corona, is somehow 4 million degrees. What gives? In April, scientists announced the main reason: small bursts of magnetic energy called nanoflares, which temporarily heat pockets of gas to 20 million degrees. “The sun’s surface is much like a pot of hot oil on the stove,” says NASA solar scientist James Klimchuk. “Hot oil rises, spreads out horizontally, cools and falls back down to the bottom of the pot, only to rise again.” That constant movement can twist and tangle the magnetic fields that thread through the sun and extend into the corona. Eventually, like a rubber band, they reach a point where they snap. Scientists had theorized this would cause a nanoflare.…

Discovering one of South America’s most intriguing dinosaurs was child’s play: Diego Suarez was just 7 when he found the first fossils of the 145-million-year-old herbivore that would bear his name, Chilesaurus diegosuarezi. The hard work began when paleontologists tried to fit it into the dinosaur family tree. Chilesaurus, which grew to about 10 feet long, has a previously unseen mix of primitive and advanced skeletal features. After analyzing fossils from more than a dozen specimens, researchers reported in April in Nature that the herbivore was actually a kinder, gentler cousin of such bitey carnivores as T. rex and Velociraptor. Chilesaurus is a rare example of a species from the generally predatory theropod group that evolved into a plant-eater.…

Mercury was the “dead” planet when NASA’s MESSENGER mission launched in 2004. But the spacecraft’s 2011 orbital arrival, and more than 250,000 subsequent images, documented an active planet. Running on fumes this year, MESSENGER (short for Mercury Surface, Space Environment, Geochemistry and Ranging) saved the best for last, swooping just miles above the virtually atmosphereless planet. It gathered fresh evidence for frozen water in crater corners, strange rock features called hollows and the evolution of a magnetic field almost 4 billion years old. The craft finally smacked into Mercury at 8,800 mph on April 30. This view of 1,000-mile-wide Caloris basin — among the largest known asteroid impacts in the solar system — shows how lava (orange) filled the blast site before new craters excavated the original basin (purple).…

When Norwegian researchers brought up a mud core from the floor of the Atlantic Ocean in 2010, they were orchestrating a family reunion. After 2 billion years of separation, a descendant of our distant common ancestor, a simple microorganism, has been discovered in the sediment by molecular biologists at Uppsala University in Sweden. All nonviral life on Earth belongs to one of three domains. Complex organisms, distinguished by nucleated cells, collectively belong to Eukarya. The other two domains, genetically different yet both structurally simple, are Bacteria and Archaea. One of the great puzzles in biology is how simple life evolved to become complex. The Archaean discovered under the Atlantic — dubbed Lokiarchaeota in Nature in May — appears transitional, showing an unprecedented degree of genetic overlap with eukaryotes. For instance,…

In January, scientists discovered a potential new class of antibiotic — by digging through dirt. Soil microorganisms secrete much-desired antimicrobial compounds that yield novel drugs, but they’re fickle: Ninetynine percent of microbial species won’t grow in labs. So Kim Lewis’ team at Northeastern University in Boston devised a method to isolate microbes in their natural environment to test their therapeutic potential. After screening more than 10,000 soil bacteria samples, they identified Eleftheria terrae, which deploys the chemical teixobactin. In tests on mice, teixobactin obliterated drugresistant bacteria — and target cells didn’t develop resistance to it. In fact, Lewis says it’s unlikely bacteria could engineer defenses against teixobactin within 40 years, if at all. The timing couldn’t be better. Unless our antibiotics arsenal expands, drug-resistant infections could kill more people globally…

Many animals use Earth’s magnetic field for navigation, but exactly how they detect it has been a puzzle — until now. For the first time, researchers at the University of Texas at Austin have pinpointed a specific pair of neurons that act as a magnetic sensor in the simple worm C. elegans. The neurons function as an internal compass, giving the worm a sense of up and down, likely to help them find food, which varies in availability and quality at different soil depths. By adding a fluorescent marker to the neurons, researchers could watch the pair light up when exposed to magnetic fields. They also observed that hungry worms burrowed downward, where food was likely to be more plentiful in their natural environment, even when they were in a…

Long-necked, massive sauropod dinosaurs like Brontosaurus, towering “cows” of the Late Jurassic, didn’t start out that way. Their predecessors were small and walked on two legs. South Africa’s Pulanesaura eocollum, which lived about 190 million years ago during the Early Jurassic, gives us a peek at that transition: One of the earliest sauropods, it’s the first with anatomy that shows it walked on all four legs. At about 26 feet long, Pulanesaura was petite compared with later sauropods and had a relatively short neck, but one with greater flexibility than its bipedal ancestors. Its neck physiology, which has hallmarks of later, larger kin, indicates that it was a low browser, sweeping its head back and forth, unlike its close relatives — living at about the same time and in the…

For the first time, astronomers have spotted an aurora, akin to our northern and southern lights, shimmering on a world outside our solar system. The find may bolster the search for extraterrestrial life, since the magnetic fields that drive auroras likely keep planets habitable. Every planet in our solar system (and even some moons) with a moderate magnetic field boasts these celestial light shows. They occur when charged space particles, typically from the sun, stream along a planet’s magnetic field lines and interact with atmospheric atoms, producing not only optical light but also radio emissions. Gregg Hallinan of the California Institute of Technology and colleagues have detected both types of radiation from what appears to be a brown dwarf, an object that straddles the boundary between planet and star. The…

Oxytocin cements the bond between mother and child, and even between lovers. But precisely how does the hormone do this? In a paper published in April, research revealed oxytocin stimulates key neural circuits that permanently alter behavior in lab mice. When baby mice fall out of their nests, their distress calls prompt their moms to retrieve them. Virgin females, however, are utterly indifferent to these cries — until they’re given a surge of oxytocin. The hormone works by binding to brain cell receptors. A New York University team looked at the effects of oxytocin three different ways. They injected it into the mouse’s bloodstream or infused it onto the area of the brain that processes sound. They also stimulated the brain to release more of the hormone on its own.…

Most of us probably take for granted that physical pain — whether it be from a sports injury, a kidney stone or appendicitis — can be attributed to some form of inflammation and that it will end. Neuropathic pain, however, affords its sufferers no such luxuries. It’s chronic and unrelenting, and its cause is unknown, making treatment difficult. It turns out that neuropathic pain is triggered when the body experiences endoplasmic reticulum (ER) stress, a condition in which the production and transport of protein exceeds the cells’ capacities, say researchers from the University of California, Davis. Because diabetics are at high risk of having neuropathic pain, the team studied diabetic rats that had neuropathic symptoms: hypersensitivity to touch and lack of heat sensation. And the rats’ nerve cells showed clear…

Researchers have found evidence of the earliest known dental procedure, and it’s not pretty. While examining the lower molar of a 14,000-yearold skeleton unearthed in northern Italy, University of Bologna archaeologist Stefano Benazzi discovered the tooth had a large cavity and numerous markings near it. Benazzi and his colleagues reported in Scientific Reports in July that the marks were made with a stone tool in an attempt to remove infected material from the cavity. The procedure “would have been quite painful,” says Benazzi, who added it was only partly successful (though at least the patient survived). His analysis included replicating the damage on modern teeth — relax, he used teeth that were already extracted. The discovery means dentistry is at least 5,000 years older than previously thought.…

The honeybee’s immune system has a few tricks up its sleeve — tricks that scientists could soon tap to protect stressed bee populations. Insects don’t produce antibodies, the immune system’s way to remember and arm the body against recurring pathogens. Yet bees somehow pass along pathogen immunity to their young, something that shouldn’t be possible without antibodies. The missing mechanism lies within vitellogenin, a protein that transfers fat into egg yolk, says Gro Amdam, a biologist at Arizona State University. In research published in July in PLOS Pathogens, Amdam and colleagues in Finland show that this seemingly simple protein can bind to “pathogen patterns.” These patterns are like molecular fingerprints for an invading microbe. Vitellogenin shares these patterns through the mother’s hemolymph (the bee version of blood) with the developing…

Buckyballs, carbon compounds shaped like soccer balls, can survive between stars and absorb their light, astronomers announced, helping solve a nearly century-old mystery. In 1919, Mary Lea Heger, a graduate student at the University of California, Berkeley, saw that certain stars were missing some colors. Something between the star and Earth must be absorbing them, but what? In 1993, a team led by John Maier of the University of Basel in Switzerland found that buckyballs encased in a frozen solid absorbed the right colors. But did they behave the same way in interstellar space? In July, Maier and his team proved it. They chilled buckyballs to nearly absolute zero and put them in a vacuum, mimicking the conditions of the cosmos. The balls absorbed the same colors missing in space.…

In July, an Iowa District Court sentenced biomedical researcher Dong-Pyou Han, formerly of Iowa State University, to 57 months in prison and $7.2 million in restitution for scientific misconduct. The unusual sentence sparked debate among scientists on whether the punishments fit the crime. Han altered rabbit blood samples to artificially boost HIV vaccine test results, leading to millions in grant money. A 2013 investigation by the U.S. Office of Research Integrity uncovered his misdeeds. The agency imposed a three-year research ban on Iowa State, which returned $500,000 in grant money. Criminal charges followed in June 2014 after the case gained widespread attention. Extreme fraud like Han’s is rare, but subsequent legal prosecution is almost unheard of, says Daniele Fanelli, a meta-researcher at Stanford University. Fanelli believes similar prosecutions may follow.…

Good news for exoplanet enthusiasts: For the first time, astronomers have found an Earth-like planet within a sunlike star’s habitable zone. The new world — named Kepler-452b after the orbiting telescope that found it — has a diameter just 1.6 times Earth’s, and it takes 385 days to orbit its star, Kepler-452. The planet’s orbital distance is just 5 percent farther away than Earth’s, putting it safely within its star’s habitable zone (green in this diagram). That means liquid water — and thus potentially life — can occur there. Unfortunately, at 1,400 light-years away from Earth, Kepler-452b is too distant for scientists to learn much more about the planet’s habitability.…

For 85 years, Pluto has been a blank space in our portrait of the solar system, so obscured that astronomers did not even know its exact size or color. But no longer. On July 14, NASA’s New Horizons probe flew just 7,750 miles past Pluto’s surface and began radioing back detailed pictures. The sudden unveiling has revealed a complex and inexplicably varied landscape. “It’s a total surprise,” said mission leader Alan Stern as he pondered the images. “If an artist had painted this Pluto before our flyby, I probably would’ve called it over the top.” Some areas of Pluto appear dark and heavily cratered, indicating extreme age. Their coloration may come from frozen methane irradiated by the sun and converted into tarlike compounds known as tholins, notes Will Grundy of…

To learn more about the evolution of the “power squeeze” — the grip we use to hold a hammer — University of Kent anthropologist Matt Skinner compared hand and wrist bones from living and extinct hominids using 3-D X-ray technology. Human hand bones showed increased density in certain key spots associated with toolmaking. In research reported in Science in January, Skinner found the same modifications in corresponding bones from Australopithecus africanus, possibly a direct ancestor of the Homo genus, which suggests that toolmaking was an earlier adaptation than previously thought. Could this help us identify the Lomekwian toolmakers? “The main point,” says Skinner, “is that there was no Homo around [3.3 million years ago], so it would either need to be Australopithecus or Kenyanthropus who made those tools.”…

Rosetta became the first spacecraft to orbit a space iceball when it reached Comet 67P/Churyumov-Gerasimenko in 2014. This year we learned even more about the ancient object and, in turn, the solar system. “Comets have been stored far from the sun in a deep freeze,” says Rosetta principal investigator Alan Stern of the Southwest Research Institute. “They represent samples of the original material out of which planets were formed.” Rosetta’s been telling the comet’s secrets ever since its May 2014 arrival, starting with its rubber duckshaped body, 4.1 miles long with a head 1.6 miles wide. Fluffy dust up to 16 feet thick coats the comet’s surface and acts like sunscreen, protecting the vulnerable ice from the sun’s heat. This has kept 67P together despite its millions of close encounters…

Scientists have warned for years that we’re heading toward a mass extinction. A June study offered the most damning evidence yet that the sixth great extinction is underway — and that it’s driven by us. Even using more conservative estimates, lead author Geraldo Ceballos of the National Autonomous University of Mexico concluded that species are vanishing up to 100 times faster than they would without human impacts. We are “precipitating a global spasm of biodiversity loss,” he wrote in the Science Advances study. Climate change is an increasingly significant driver of that loss, according to a separate analysis published in Science in May. University of Connecticut ecologist Mark Urban, who reviewed 131 studies predicting the effects of warming on plants and animals, found that extinction risk accelerates with every degree…

A new DNA analysis of a bone fragment from an ancient skeleton may have settled an almost 20-year debate between Native Americans and scientists over rights to the bones. The analysis shows that Kennewick Man — a nearly 9,000-year-old skeleton found in 1996 in Washington state — shares ancestry with modern Native Americans. The analysis also allowed the researchers to link the skeleton to a specific group of Native Americans. Evolutionary geneticist Eske Willerslev of the University of Copenhagen, who has sequenced other ancient DNA samples, led the team that extracted DNA from a tiny fragment of hand bone and used it to sequence the skeleton’s genome. The analysis, published in June, showed that Kennewick Man is related to modern Native Americans and shares ancestry with members of the Confederated…

The Agricultural Revolution of 12,000 years ago was apparently not so revolutionary. Researchers traditionally draw the divide between Paleolithic huntergatherers and Neolithic farmers about 12 millennia ago, with the onset of agriculture in the Middle East. But a study published in July in the online journal PLOS One indicates that at least in one corner of modern-day Israel, humans were farming 23,000 years ago. Since 1989, archaeobotanist Ehud Weiss of Israel’s Bar-Ilan University and his team have collected some 150,000 specimens of plant remains from the settlement known as Ohalo II. Located on what was the shore of the Sea of Galilee 23,000 years ago, when water levels were significantly lower, the site was eventually destroyed by fire. The charring helped preserve plant remains at the site, which was then…

It shouldn’t have been there, but there was no denying that it was there: a channel guiding immune cells directly into the brain. The serendipitous discovery by a University of Virginia team may eventually help explain many neurological diseases. Previously, researchers assumed immune cells took an indirect route around the brain, flowing freely through its surrounding fluid. That’s because lymphatic vessels, which transport immune cells throughout the body, stopped at the upper neck. So neuroimmunologist Jonathan Kipnis and his team weren’t looking for lymphatic vessels actually entering the brain. “You don’t look for something that doesn’t exist,” Kipnis says. But when Antoine Louveau, a researcher in Kipnis’ lab, developed a dissection technique that wholly preserves the fragile membranes covering the mouse brain, it revealed something never seen before: Immune cells…

When it comes to electronics, smaller is usually better. And as devices get more compact and powerful, they need ever-tinier transistors — the internal switches that keep computers computing. Easy to use and abundant, silicon has been the go-to transistor material for decades, but in February, the world saw the first silicene transistor. Silicene is a twodimensional version of silicon just a single layer of atoms thick. It behaves like a superstrong electron superhighway, a quality that may lead to flexible and transparent electronics. Silicene debuted in 2012, but it degrades within seconds when exposed to air. “It needs to be protected at all times,” says Deji Akinwande, the University of Texas at Austin engineer who led the work. So Akinwande’s team first grew silicene on a silver base and,…

Thousands of mutations are linked to disease, yet only a few cause illness by directly disrupting proteins, the cell’s workhorses. Scientists have figured out how several of the other mutations spur disease. Using thousands of tissue samples from cadavers, researchers on the Genotype-Tissue Expression project (GTEx) isolated and sequenced DNA and a variety of protein-encoding RNAs from each sample. Many disease-linked mutations, it turned out, lie in stretches of DNA that don’t encode proteins themselves but instead regulate genes elsewhere in the genome that then go on to disrupt tissue function. Genomic makeup also can affect to what extent genes are turned on or off in a person’s tissues, thereby causing disease, says Kristin Ardlie, a Broad Institute biologist who coled the analysis published in May.…

Thanks to comparatively plentiful fossils, ceratopsids — horned and frilled dinosaurs with rhinolike bodies, such as Triceratops — are among the best-studied dinosaurs. But there are still surprises to be found. Consider the 68-million-year-old, nearly complete skull of Regaliceratops peterhewsi (left), found in Alberta, Canada, and described in Current Biology in June. The dinosaur has a unique frill that Royal Tyrrell Museum paleontologist Caleb Brown, part of the research team, says one fan on social media likened to “looking like the animal ripped the plates off a Stegosaurus and used them to adorn itself.” Wendiceratops pinhornensis (right), also from Alberta and described in PLOS One in July, has its own distinctive display: an elaborate assemblage of massive horns and a frill with dramatic, curving hooks. Paleontologists have found scores of…

In January, scientists in Antarctica discovered something amazing: fish living in a dark pocket of seawater under nearly a half-mile of ice. Scientists from the University of Nebraska-Lincoln and other universities bored a hole into an isolated nook where glaciers ooze off the coast and form the massive Ross Ice Shelf, a slab of floating ice the size of Spain. The hidden spot, 500 miles in from the ice’s edge, is far removed from life-sustaining sunlight, so the researchers expected to find only microbes. But when they sent down an aquatic robot, its camera revealed fish, crustaceans and other animals. It is the farthest under an ice shelf that animals have ever been found. “It’s remarkable,” says James McClintock, a marine biologist from the University of Alabama at Birmingham, who…

Saturn’s moon Enceladus made waves in 2015 with two dramatic liquid-waterrelated discoveries, establishing the world as a target of great interest in the search for life. After astronomers analyzed seven years’ worth of Enceladus data from NASA’s Cassini probe, they detected a slight rocking motion in the moon’s rotation, suggesting an outer shell of ice. “That could only be the case if the ice shell was not frozen to the core but separated by a layer of liquid,” says team member Carolyn Porco. The team believes a shallow global ocean, perhaps only a mile deep, lies between Enceladus’ rocky core and its 30-mile-thick icy crust. At the south polar region, where about 100 saltwater geysers erupt from the surface, the ocean is likely deeper and the crust thinner. This news…

In the late 1970s, two mathematicians, John Conway and Simon Norton, saw a deep connection between two mathematical objects that should have nothing to do with each other. On one side of the link was a fundamental object in number theory called the j-function. On the other was a mysterious entity that described a new kind of symmetry, but might not even exist. If it did, though, it would be enormous (8x1053 components), so they dubbed it the “monster group.” The connection sounded so crazy, Conway and Norton called their theory “monstrous moonshine.” In 1992, Richard Borcherds proved monstrous moonshine: He found the link between the monster group (which does exist) and the j-function through string theory, the idea that the universe is made of tiny strings vibrating in high…

Entombed for millions of years deep within South Africa’s Sterkfontein Cave, one of the most complete early hominin fossils ever discovered is reshuffling our family tree. Nicknamed Little Foot for its modest size, the skeleton was estimated to be 2.2 million to 3 million years old. More accurate dating of the sediment in which the fossil was found, however, establishes that it’s 3.67 million years old. Until now, Little Foot was considered a more recent species than Lucy, the famous 3.2-millionyear-old Australopithecus afarensis from Ethiopia often cited as our direct ancestor. But Little Foot’s new age, published in Nature in April, suggests that hominin diversity and range was much greater much earlier than we previously thought. Some researchers have classified Little Foot as A. africanus, a later australopith found only…

To celebrate Hubble’s 25th anniversary, scientists captured a new look at a starforming region seen in one of the space telescope’s most iconic images. Using its latest camera, Hubble shows a wider and sharper view of the Eagle Nebula’s “Pillars of Creation,” immense columns of cold gas bathed in the ultraviolet light of nearby massive young stars. Such an environment likely reflects the same kind of setting in which our sun formed 4.5 billion years ago.…

Working with stem cells comes at a price. When isolated, 99 percent of stem cells die, making it prohibitively difficult to manipulate their genes or expand their numbers for clinical use. By tinkering with the medium in which cells are grown, researchers at the Salk Institute for Biological Studies created a type of stem cell with a survival rate of 30 to 40 percent, vs. 1 percent. The cells are far easier to culture, and their genetic defects are more readily repaired. The human version of the cells, called region-selective pluripotent stem cells, or rsPSCs, can also grow inside a mouse, something other human stem cells can’t do, says Jun Wu, a research associate involved in the work, published in May in Nature. “It offers the first proof of concept…

While hunky Chris Pratt was motorbiking through the Jurassic World jungle with his soupedup troupe of velociraptors, real paleontologists were analyzing unique fossilized tracks from a raptor that was on the loose more than 100 million years ago. Published in May in Palaeoworld, their report documents the first imprints of a raptor’s third-toe claw. Like velociraptors, the raptor that made the tracks came from a group of dinosaurs known as deinonychosaurs, which walked and ran on two toes. Deinonychosaurs typically kept the third toe of each foot raised and its claw retracted, like your average house cat, to protect the valuable weapon. “The ground would dull the claw,” says University of Alberta paleontologist Scott Persons, part of the research team. “That’s also why a cat’s claws can rough you up,…

Deep underground, beyond a 39-foot vertical shaft narrowing to 8 inches in some spots, tantalizing clues of humanity’s earliest origins are whispering up from the darkness. Here, in the Dinaledi Chamber of South Africa’s Rising Star cave system, researchers have found a spectacular assemblage of fossils they say belongs to a new human species: Homo naledi. In September, University of the Witwatersrand paleoanthropologist Lee Berger and his team described the fossils — discovered by spelunkers in 2013 — in the journal eLife. Media hoopla surrounding speculation about H. naledi’s behavior distracted attention from what made the discovery so scientifically important: the unprecedented quantity of bones. Ancient hominin fossils are rare, and those from early members of our own genus, Homo, are rarer still. So it is all the more astonishing…

Getting an annual flu vaccine is a drag. It takes time. It might not work. It hurts. Public health experts have long fantasized about giving people one jab that would safely last a lifetime and protect against all kinds of flu. That dream is still a long way off, but the prospect of giving people one vaccine that could provide wide protection for at least a few years is getting more realistic. In a pair of papers in Science and Nature Medicine in August, two teams of scientists demonstrated a new approach for making a universal flu vaccine. Figuring out the molecular structure of the flu virus, which researchers detailed in two key papers in 2009, enabled scientists to realize they had been targeting only the head of the virus,…

Over a million soldiers have served in the wars in Iraq and Afghanistan. Of the men and women who have returned from combat, more than 100,000 have been diagnosed with posttraumatic stress disorder (PTSD). Over 300,000 more have been told they have a traumatic brain injury (TBI). In many cases, symptoms are the same: insomnia, anxiety, irritability, poor concentration and limited impulse control. TBI and PTSD Scan Comparison Chart The treatments for these two conditions are very different. The problem is, there hasn’t been a consistently accurate diagnostic test to distinguish between PTSD and TBI. That changed earlier this year when two studies, one of which involved 20,746 patients, found that a type of medical imaging called single photon emission computed tomography (SPECT) showed clear differences in the brains of…

The search for a genetic link to depression, which affects 350 million people worldwide, has come up empty for years. While some people become depressed after a mild stressful event, others remain resilient to catastrophe. A British researcher and his team found two areas in the genome that appear to be key to depression. To make sure he recruited only patients with major depression, Jonathan Flint, a psychiatrist from the University of Oxford who led the study, says he examined older generations of Han Chinese women. As a result, his patients did not have many of the complicating factors of depression. “None of them drink alcohol, none of them smoke, and other drug abuse is rare,” he says. Flint’s team collected DNA samples from more than 5,000 women with major…

Antarctica is losing more ice than ever, scientists reported in 2015. Its ice shelves — the thick, floating slabs that encircle the continent — are taking the biggest hit. The shelves slow and stabilize the glaciers behind them, but they are succumbing to a hidden force: Deep, warming ocean currents are melting the ice from beneath. The collapse of several small ice shelves has caused glaciers to accelerate two- to ninefold and spill more ice into the ocean, raising the sea level. A study published in April shows that more ice shelves are coming into play: From 1994 to 2012, the rate of ice shelf shrinkage increased twelvefold. Parts of the ice sheet considered at risk hold enough ice to raise the global sea level by 22 feet. Here’s how…

A piece of fossilized jaw discovered at Ledi-Geraru, Ethiopia, pushes back the date when the first members of the human genus evolved by 400,000 years. The research, published in March in Science, shows that the jaw is about 2.8 million years old. It’s one of the few hominin fossils that date to between 2.5 million and 3 million years ago, when a small-brained australopith was evolving into the larger-brained Homo genus. During this period, a changing climate forced our ancestors to move out of the forests and into more open territory. They had to adapt to new foods and new predators, which may have spurred the development of our distinctly larger brains. Animal fossils found near the jaw fragment suggest the individual lived in a savannah environment. “It confirms this…

In August, the FDA approved Addyi, the first drug authorized to treat hypoactive sexual desire disorder (HSDD), or lack of libido. As the first such pharmaceutical designed for women, the press dubbed it Female Viagra — incorrectly, since Viagra and its cohort address the physical issue of erectile dysfunction and are taken as needed. Addyi, or flibanserin, tweaks the brain’s mix of neurotransmitters dopamine and serotonin, must be taken daily and can take two months to fully kick in. Unfortunately, the results are, um, anticlimactic. Relative to the placebo, only an additional 10 percent of women in trials had a marked response: hardly one more sexually satisfying event per month. “Not very many, in light of all of the significant side effects,” worries Lori Brotto, a University of British Columbia…

Cleaning oil spills could be as easy as scraping frosting off a cake, thanks to a nanoparticle coating developed by Philip Brown and Bharat Bhushan, engineers at the Ohio State University. Traditional chemicals that disperse oil spills can harm marine life more than the oil itself. Instead, environmentalists might one day use specially coated nets that separate oil from water. The coating, announced in March, covers a stainless steel mesh and works by first adding silica nanoparticles to create a bumpy, liquid-repelling surface. Next comes a polymer layer that acts as a binder, followed by a layer of surfactant, a molecule with two key parts: one that loves water and another that hates oil. The surfactant’s different response to the two liquids allows the coated mesh to separate them. When…

Internet connections can be wireless, so why shouldn’t brain medicine be? Stimulating neurons deep within the brain can help treat conditions such as Parkinson’s disease and obsessivecompulsive disorder, but right now patients must undergo invasive electrode implants. In 2015, two research teams announced they found a way to skip the implants and stimulate the brain remotely. Hot, Hot, Hot In March, MIT materials scientist Polina Anikeeva and her team announced they’d heated things up by injecting a specially engineered virus that carried a gene for heat sensitivity — the same one that gives us a “hot” sensation when we eat chili peppers — into a region of mouse brain. Once the virus infected neurons with the heat-sensing gene, the researchers injected magnetic nanoparticles into the same brain cells. When they…

People with paralysis or an amputation can already use their minds to control robotic limbs, helping to restore their sense of independence, but the motions are often clumsy and unnatural. Researchers announced in May that they created a neural prosthetic that gives those with artificial limbs finer, smoother movements. Standard neural prosthetics ferry signals from the brain’s motion control center, the motor cortex, to a cable connected to a computer controlling the limb. These signals break down a physical task into individual movements — like listing the steps involved in grabbing your coffee mug. But this team went further upstream in the brain’s signaling chain and used signals from a patient’s posterior parietal cortex (PPC). The PPC is where your brain determines “the goal of the movement,” says principal investigator…

In a first, engineers have invented artificial immune tissues that can produce antibodies. Made from gelatin-based biomaterials and seeded with living cells, the synthetic organoid mimics lymph nodes and stimulates B cells, according to a June study in Biomaterials. B cells swing into action when the body is under attack, generating antibodies and fine-tuning them to fight specific infections. The immune organoid is up to 10 times more efficient than the current method of culturing cells in a petri dish. The potential applications for this platform, which could eventually eliminate the need to do immune system animal research, include tracking how blood cancers develop when B cells go haywire and devising new therapies to attack other cancers. The organoid could also help researchers design vaccines by exposing the B cells…

Genetically modified organisms show promise for everything from making vaccines to cleaning up oil spills. But that promise has been clouded by concerns over their potential to escape into the wild and harm ecosystems. Now, scientists have found a way to keep GMOs from going rogue. In January, researchers at Harvard and Yale reported they had reprogrammed the genome of E. coli bacteria so the cells are dependent upon an amino acid that doesn’t exist in nature. After growing 1 trillion bacterial cells and then depriving them of the synthetic amino acid, not a single one survived, suggesting they’d quickly perish in the wild. In previous efforts to contain GMOs, organisms found a backdoor escape route by evolving out of their engineered weakness or scavenging nutrients from their environment. This…

Octopuses hail from a humble neighborhood in the taxonomic tree: the mollusks, which include snails, clams and other dimwitted animals. Yet octopuses are clever critters, known to use tools in the wild, play in captivity and even watch what’s happening outside their aquarium. Scientists have long wondered how they evolved such smarts independently of mammals and birds. The sequencing of the octopus genome, published in August, offers a surprising answer. The genome shows that octopuses have the same small repertoire of neurotransmission genes as lower mollusks. This limited set of nervous-system building blocks should have restricted their ability to develop advanced intelligence, says Daniel Rokhsar, an evolutionary biologist at the Okinawa Institute of Science and Technology Graduate University in Japan. But Rokhsar and his collaborators found two vastly expanded gene…

From health monitoring sensors woven into clothing to pacemaker leads that never wear out, stretchable electronics could usher in a new era of wearable tech. But finding superflexible alternatives to metal wires and semiconducting chips has been a challenge. In July, researchers unveiled a solution: elastic wires that can withstand both extreme strain and thousands of stretch-andrelease cycles. In previous attempts at making elastic conductors, researchers embedded conductive metallic particles into an elastic insulator, but stretching the material would cause breaks in the conducting path. These new wires can expand to 10 times their original length without choking off the current. Materials scientist Ray Baughman and his team at the University of Texas at Dallas wrapped a sheet of conducting carbon nanotubes many times around a stretched rubber fiber, with…

Rainforests have been called “the lungs of the planet.” They breathe out life-giving oxygen and absorb carbon dioxide, limiting global warming. A study published in May suggests these forests are more at risk than ever, contradicting earlier reports of a slowdown in deforestation. Analyzing more than 5,000 high-resolution satellite images from the 1990s and 2000s, geographers at the University of Maryland discovered that rainforest loss accelerated by 62 percent during those two decades. “If this trend continues,” lead author Do-Hyung Kim warns, “the vast tropical forests of today may soon be a relic of the past.” 2010 United Nations report said deforestation rates were decreasing, but it turns out that analysis was based in part on unreliable government data. Even in Brazil, which succeeded in slowing deforestation for a decade,…

A new 3-D printer makes objects appear to grow from primordial goo, all in a matter of minutes. The Continuous Liquid Interface Production technology (CLIP), reported in March in Science, features a pool of specialized resin that hardens when exposed to light but remains liquefied when exposed to oxygen. A projection system flashes ultraviolet light patterns through an oxygenpermeable window beneath the resin while a mechanical arm pulls the object upward as it’s being created. Since the light and arm work in tandem, shapes and lattices can be printed continuously rather than layer by layer, like — dare we say — “old-fashioned” 3-D printers. The CLIP is fast: An intricate, 51-millimeter structure emerges from the resin in six and a half minutes. The same job with a traditional 3-D printer…

Hospital patients might someday fight pain with opioids manufactured from sugar-gobbling yeast similar to what brewmasters and bakers use. In August, Stanford synthetic biologist Christina Smolke and her team announced successfully using genetically modified baker’s yeast, one strain to convert glucose into the opioid hydrocodone and another strain to create thebaine, an opioid precursor. Other research groups completed the 15-step conversion this year using several yeast strains together, but Smolke’s team was the first to use just a single strain to pull off the conversion from start to finish. To get the more than 20 enzymes needed to complete the conversion from glucose to painkillers, the team spliced genes from plants, bacteria and even rats into yeast. The new process could yield more effective, less addictive and cheaper drugs, but…

It’s not the fabled Atlantis, but it is tantalizing: Researchers studying the Mediterranean’s Sicilian Channel, an area now underwater but partially exposed as recently as 9,000 years ago, found a 40-foot-long monolith, broken in two, with uniform, regularly spaced holes that could not be explained through any natural process. Analysis confirmed the monolith was quarried from a rock formation about 1,000 feet from its resting place. Still a mystery: Who created the monolith and other possibly man-made features nearby, including concentric circles and what may be a breakwater that’s more than 250 feet long? “We have opened the door to the unknown,” notes lead researcher Emanuele Lodolo, whose team published the find in the September issue of Journal of Archaeological Science: Reports.…