Índice para May 2016 em Discover

Roboticists made a splash last year by building a robot that duplicated one of the natural world’s niftiest tricks: jumping on water. Inspired by water striders — insects that can hop upward from watery surfaces — researchers at Korea’s Seoul National University and Harvard’s Wyss Institute for Biologically Inspired Engineering emulated the biomechanics necessary for their microrobot to vault 5.5 inches — more than 10 times its height — from water without breaking surface tension. Made from ultralight components, the tiny bot weighs just 0.002 ounce and gets its leaping power from a built-in catapult mechanism.…

It’s like science fiction: a memory of something that never happened, planted in your brain. But a team at the French National Center for Scientific Research did just that to five mice. First, the researchers monitored each mouse’s brain activity as it explored a large, open arena. As the mouse wandered, its “place cells” lit up. Each place cell is activated by a location; together, they create a spatial map in the brain. When the mouse napped later, its place cells lit up again as the brain replayed the memory of roaming the chamber. (It’s believed the sleeping brain rehashes waking experiences to create long-term memories.) Based on recordings made while the mice wandered, researchers knew which place cell lit up in each location. When a place cell encoding one…

STROLLING THROUGH A NATURE PRESERVE near the Old North Bridge in Concord, Mass., where “the shot heard ’round the world” began the American Revolutionary War, Ed Damiano is talking about another revolution, this one in the care of his son’s Type 1 diabetes. Call it the insulin shot heard ’round the world, delivered not with a handheld syringe, but automatically, from a computer-guided pump: the diabetic answer to the driverless car. “In the fall of 2017, David heads off to college,” says Damiano, a professor of biomedical engineering at Boston University. “I want to have a version of our device approved by then.” Damiano’s device is a technological tour de force that diabetics and their families have been clamoring for, and researchers have been studying, for decades. With hardware as…

For most of human history, our species has tried to understand our world. Curiosity became science, a method of testing our explanations. Most theories that were little more than myths fell by the wayside, but some clung tenaciously for thousands of years. One of them stated that beyond our ancestors’ reach was the sky: The stars and Milky Way formed a roof above Earth. Finding our true place took millennia, the result of hard-fought battles wresting science from the grip of ignorance. And history now links relatively few astronomers to the key discoveries along the way. EARLY IDEAS The first challenge encompassed the Sun, the Moon, and the planets moving among the stars. Aristarchus of Samos (310–230 B.C.) first theorized that Earth orbited the Sun, but it wasn’t until 1543…

They may look like a tasty snack, but these chips are actually plates of zinc oxide crystals growing on a zinc oxide bar. They were photographed with a dual-beam scanning electron microscope during research on high-energy storage systems at the Pacific Northwest National Laboratory in Richland, Wash., and later colorized. Zinc oxide is an effective absorber of ultraviolet light, which is why it’s a popular sunscreen ingredient. But scientists say it could also be useful in improving the efficiency of photovoltaic systems, which turn sunlight into electrical energy. The plates can grow up to 5 microns, or 1/200th of a millimeter.…

A toilet in Eric Alm’s MIT lab has contributed more to microbiology than most bathrooms. For the better part of 2009, the biologist used it to collect his own feces for analysis. The study (which also involved a colleague) may sound simple, if a little gross, but variation in intestinal microbes, known as human microbiota, is highly complex. By tracking changes to the microbiome through fecal samples, Alm hoped to learn more about how daily activities such as diet, sleep and exercise could be linked to changes in these communities of microorganisms. It was a challenge convincing his colleagues it would be a worthwhile experiment, but once the data came in, enthusiasm grew. About halfway through, Alm learned the importance of his own diet after one meal radically altered the…

Bright yellow. That was the first thing I saw as I opened the door to the room of my 1-year-old patient, Reza. He sat on his father’s lap across from me. Dark brown hair fell across his forehead, and the whites of his eyes glowed with the brilliant yellow of a highlighter marker. His skin’s dark complexion was also tinted a dull yellow, producing the sallow cast of dead grass. Reza’s father bounced him daintily on his knee to help keep him calm. Physicians call yellowing of the eyes and skin jaundice, a term from the French jaune, meaning “yellow.” During my pediatrics training, I saw innumerable cases, almost all of them in newborns. But Reza was no newborn, and seeing that familiar yellow on a much older child told…

FRESHWATER HAS ALWAYS BEEN a precious commodity on Colombia’s arid Guajira Peninsula, but climate change is turning scarcity into crisis. Most of the region’s wells are contaminated by saltwater, forcing inhabitants to rely on rainfall for potable water. After three years of extreme drought, the people of the Guajira are still waiting for the rain to come. Guajira’s water pinch is just one example of how a warming world is already hurting developing countries. And the worst is yet to come: As the global thermostat rises, extreme weather events such as droughts and floods will become more frequent and intense in many regions, the United Nations warns. Developing countries stand to suffer the most from climate change — and they have the fewest resources to prepare for it. So inventors…

Visual observing can be either a pastime or an art. Both are fine, and it’s your choice. But if you desire to see faint stars and nebulae or fine lunar and planetary details, or if you want to penetrate the veil of normal vision, push the limits of your telescope, or perhaps one day see what no one has seen before, then observing the world around you — both in the daytime and at night — can help. THE “ART” OF OBSERVATION You don’t need to be behind the eyepiece to improve your observational skills. You can start right now by studying your immediate environment — repeatedly, until you feel you’ve exhausted your visual capabilities. Let’s start with how to use direct vision to improve your observing skills. Direct vision…

The future of our species, many researchers believe, lies in sustainable megacities that can support dense populations through efficient resource management. We’ve got a long way to go. A study in the Proceedings of the National Academy of Sciences provided the first-ever comprehensive comparison of Earth’s 27 megacities, defined as metropolitan areas with populations of 10 million or more. The survey identified some big disparities: New York, for example, gobbles up significantly more energy than Tokyo, even though the Big Apple has 12 million fewer people. Gathering the data was the first step in a multiphase project to identify strategies that will help all cities effectively sip, rather than chug, available resources, says the study’s lead author Chris Kennedy, an industrial ecologist at the University of Victoria in British Columbia.…

Q I remember the early days leading up to the International Space Station. There was hope of learning new things, maybe advances in medicine or other areas that could be better studied in zero G. We get reports of people going to and from the station, but for years I haven’t heard anything about the scientific value, if any, of the space station. What are scientists working on up there? — Dick Parker, Denver A Well, they’ve definitely been busy. If Scott Kelly’s recent yearlong stint in space isn’t enough for you, scientists affiliated with the International Space Station (ISS) have conducted almost 1,800 investigations and published more than 1,100 studies since assembly of the station started in 1998. Sometimes, constraints of life on the ISS stoke innovation. One example:…

On a sunny April afternoon in 2013, while my dad was driving home after work, a 26-year-old man in a Toyota Camry broadsided him. The impact sent my dad’s Cadillac careening into a brick retaining wall. Paramedics had to saw off the door to extract him from the vehicle. When I saw him several hours later, he was conscious but had no recollection of the crash. His blood pressure was so low doctors could barely detect a pulse. They thought they were losing him. Then something strange happened. “I could feel myself slipping away as the nurses probed for a vein to give me blood,” he told me the next morning. “All of a sudden, I was overcome by an eerie silence. There was no sound at all. I saw…

To understand the drive that fuels paleontologist Nizar Ibrahim, just ask his longtime mentor, British paleobiologist Dave Martill, about one of their early expeditions. It was 2008, and their team was hours away from the nearest village in the sweltering, empty deserts of Morocco. They had come to analyze ancient sediment layers, not to hunt dinosaurs. But Ibrahim, then in his mid-20s, spotted an enormous fossilized bone on a steep slope. The team wasn’t prepared to excavate a fossil, never mind one weighing about a hundred pounds. They didn’t even have plaster of Paris — a paleontologist’s go-to goo to prep fossils for transport from the field. Ibrahim was undeterred. “He said, ‘I must have this,’ ” says Martill, with a sigh, from his office at England’s University of Portsmouth.…

AN ASTRONOMER SEARCHING FOR ALIEN WORLDS and an outfielder tracking a fly ball on a sunny afternoon face a common challenge. They both run into the problem of “contrast.” Simply put, the object they seek is not only small but exceedingly faint compared with the blazing star nearby. Baseball players have learned to get around this issue by blocking the sun’s light with an outstretched hand. Astronomers might want to try a similar trick. Of course, it is much harder for planet hunters. In our solar system, for instance, Earth is 10 billion times fainter than the sun in terms of visible light. Trying to see an Earth twin around another star “is like trying to see a firefly fluttering less than a foot from a huge searchlight — when…

Cash and Anthony Harness hoped to take starshades into the realm of astronomy in a trial planned for Utah’s Bonneville Salt Flats — famous for its dark skies and flat, open terrain ringed with mountains. After planting a starshade atop a small mountain, they would have mounted a telescope in a truckbed and waited for the star to duck behind the shade. By moving the telescope a few miles per hour on the truck, they could theoretically get good views continuously for about half an hour. Unfortunately, they never got the funds. While it may still happen in the future, Cash has found another alternative: Northrop Grumman’s Steven Warwick and Harness have been using the McMath Solar Observatory on Arizona’s Kitt Peak to create a non-moving image of a star,…

Late one November afternoon in 1532, Atahualpa, the ruler of the Inca Empire, approached Cajamarca, a town couched in a valley of the Peruvian Andes, to meet with a small band of foreigners. His empire stretched from modern Ecuador south, between the Pacific and the Andes mountains, to central Chile. Having just won a costly but decisive victory against his brother in a battle of succession, Atahualpa approached his new visitors without fear. He left the majority of his soldiers, who numbered in the tens of thousands, camped outside the town. Accompanied by a retinue of several thousand unarmed men, Atahualpa was ceremoniously carried into Cajamarca on a litter. He wore an impressive emerald collar, while the lords, counselors and commanders who accompanied him were adorned in richly colored clothing…