开心农民Top stories- Facial expressions that aren’t universal, a new icy world, and how high altitudes change your bloodTop stories: Facial expressions that aren’t universal, a new icy world, and how high altitudes change your blood Facial expressions—including fear—may not be as universal as we thoughtWhen you’re smiling, it may feel like the whole world is smiling with you, but a new study suggests that some facial expressions may not be so universal. In fact, several expressions commonly understood in the West—including one for fear—have very different meanings to one indigenous, isolated society in Papua New Guinea. The new findings call into question some widely held tenets of emotional theory, and they may undercut emerging technologies like robots and artificial intelligence programs tasked with reading people’s emotions.New clues to how lithium soothes the bipolar brain may shed light on other mental illnessesLithium has for decades been recognized as an effective mood stabilizer in bipolar disease, yet exactly how lithium soothes the mind has been less than clear. Now, a team led by Ben Cheyette, a neuroscientist at the University of California in San Francisco, has linked its success to influence over dendritic spines, tiny projections where excitatory neurons form connections, or synapses, with other nerve cells. Lithium treatment restored healthy numbers of dendritic spines in mice engineered to carry a genetic mutation that is relatively common in people with autism, schizophrenia, and bipolar disorder.New icy world with 20,000-year orbit could point to Planet NineThe solar system has gained a new extreme object: L91, a small, icy world with one of the longest known orbits, taking more than 20,000 years to go around the sun. Researchers have yet to pin down the object’s size or mass, but they can add it to the growing list of frozen bodies circling well beyond Neptune in strange orbits that imply gravitational disruptions from outside the sun and the known giant planets. In the case of L91, some astronomers say that external disrupter could be a ninth giant planet, as yet undiscovered.Two weeks in the mountains can change your blood for monthsScientists have long known that the body adjusts to the oxygen-deprived conditions of high altitudes. The traditional explanation has been that low-oxygen conditions cause the body to build new red blood cells, making it easier to supply oxygen to muscles and vital organs. But mountaineers, backpackers, and other high-country weekend warriors have long known that this story might not be quite right. It takes weeks to produce new red blood cells, and even ordinary people can adapt within days. Now, a new study—the first to look closely at the blood of people trekking up and down mountains—has found that the body begins adapting to elevation as soon as overnight due to a change in the oxygen-carrying protein hemoglobin.Bizarre fish face wins Nikon photography prizeIf you have never been face-to-face with a fish embryo, now is your chance. A bizarre photo of a 4-day-old zebrafish face is the winner of this year’s Nikon Small World photography contest. Geneticist Oscar Ruiz and his team at the University of Texas MD Anderson Cancer Center in Houston faced the difficult task of mounting the fish embryo at just the right angle to bring its face in focus of their microscope. As luck would have it, the first image they took was a ringer. Now, Ruiz says, they are able to take similarly close time-lapse images of living fish as they grow to study facial development at the cellular level.Now that you’ve got the scoop on this week’s hottestSciencenews, come back Monday to test your smarts on ourweekly quiz!