Wendy Science

Archaeological sites along the southern coast are yielding fresh insights into an enduring mystery of human evolution By | | Excavators reveal Middle Stone Age artifacts on a landsurface at Vleesbaai that dates to around 70,000 years ago. The red sediment is a paleosol (ancient soil) and a dune is stratified above. More on this Topic In the of the August Curtis Marean of Arizona State University tackles a longstanding question in paleoanthropology:  how did our species, disperse so far and wide? Other human species colonized Africa, Europe and Asia, but only our kind managed to spread across the entire globe. Marean suggests that the emergence in our species of a special propensity for cooperation and the invention of a game-changing technology—projectile weaponry—powered our ancestors’ march across the planet, allowing them to go places no member of the human family had gone before. Marean’s hypothesis derives in part from discoveries he and his colleagues have made at archae...

Noah’s Ark supposedly provided shelter to animals from the rising floodwaters. But at a federal breeding site near Shasta Lake, Calif., the opposite is occurring: The tanks of Livingston Stone National Fish Hatchery are providing refuge this summer for salmon nearly out of water. There, staffers are rearing the only insurance policy that the Sacramento River’s winter-run Chinook have against extinction: a living genetic bank of 1,035 baby fish, selected to reseed the population should it extinguish in the wild. Unique coloring, genetics and size distinguish this subspecies, which is protected under the Endangered Species Act. The Golden State’s extreme drought, now well into its fourth year and said by climate scientists at the University of Minnesota and Woods Hole Oceanographic Institution to be the state’s worst in more than 1,200 years, has been accelerating the anticipated demise of several of California’s endangered fishes, including its salmon. A total of five species and subsp...

Telltale differences in the brain and immune system before deployment may predict which soldiers are most likely to succumb later on By THIS IS A PREVIEW. or to access the full article.Already a subscriber or purchased this issue? The bomb that shattered Travis Adams's peace of mind never actually exploded. Its timer went off, but the bomb malfunctioned. Still, the 25-year-old U.S. marine remained haunted by the memory of an explosive device diabolically concealed beneath a tempting array of cookies and candies. Whoever had set it that day in Iraq must have planned to blow up children. “People are evil if they're willing to do that,” he recalls thinking. Adams had his share of close calls during his nine years of active duty, including a mortar that landed 50 yards from his bed one night. But he could not shake off his horror of the candy bomber, which soon metastasized into a broader distrust of his superiors and even himself. By the time Adams returned home to San Diego ...

For years now, “Extinction Countdown” readers have followed the slow slide toward extinction of the northern white rhino (). In 2014 we lost two members of the species, bringing the . Now word comes that one more has died, leaving only four. Nabiré, a 31-year-old female, passed away on July 27 at Dvůr Králové Zoo in the Czech Republic, where she has spent her entire life. She had been suffering for years from an untreatable cyst that the zoo recently drained. Even then it weighed an estimated 40 kilograms. She also had cysts in one of her ovaries and and could not give birth due to other abnormalities. "It is a terrible loss,” zoo director Přemysl Rabas said on the . “Nabiré was the kindest rhino ever bred in our zoo. It is not just that we were very fond of her. Her death is a symbol of the catastrophic decline of rhinos due to a senseless human greed.” Nabiré’s death leaves an elderly female at the San Diego Zoo, plus one male and two females at Ol Pejeta Conservancy in Keny...

It was an otherwise normal day in November when Madeline Lancaster realized that she had accidentally grown a brain. For weeks, she had been trying to get human embryonic stem cells to form neural rosettes, clusters of cells that can become many different types of neuron. But for some reason her cells refused to stick to the bottom of the culture plate. Instead they floated, forming strange, milky-looking spheres. “I didn’t really know what they were,” says Lancaster, who was then a postdoc at the Institute of Molecular Biotechnology in Vienna. That day in 2011, however, she spotted an odd dot of pigment in one of her spheres. Looking under the microscope, she realized that it was the dark cells of a developing retina, an outgrowth of the developing brain. And when she sliced one of the balls open, she could pick out a variety of neurons. Lancaster realized that the cells had assembled themselves into something unmistakably like an embryonic brain, and she went straight to her adviser...

France, one of the world’s leaders in nuclear energy production, plans to draw down nuclear’s share of electricity generation from 75 to 50 percent by 2025—giving itself a 10-year time frame equivalent to the complete shutdown now ongoing in Germany. Which reactors are to be disconnected is not specifically mentioned. “Finally!” gasped French headlines last week. After months of national debate—of amended drafting bills and a one-year parliamentary discussion interspersed with joint committee reports and opposition intransigence—the nation approved an Energy Transition Law that many are now calling historic in scope and ambition. A political fight is sure to follow, with some observers worried by a cap of 63.2 gigawatts that may provide too much leeway to the embattled industry. Yet it’s also clear the momentum has already shifted, with environmentalists exulting in their apparent victory. “This law opens up all renewables sectors to new energy horizons,” said Jean-Louis Bal, the pr...

The mysterious gunk on Jupiter’s moon may be sea salt By | | Cracks and ridges crisscross Europa. Alien life may flourish in subsurface oceans on Jupiter's Europa, but another of the icy moon's secrets is displayed in plain view: a mysterious “brown gunk” filling many of the fissures, fractures and craters that crisscross its face. “That is our state-of-the-art term for it—brown gunk,” says NASA'S Curt Niebur, who explained at a recent conference that the unknown substance most likely is carried to the surface by water erupting from Europa's depths. “If we can determine what that brown gunk is,” Niebur explains, “we can then understand what is in the water, what is in the oceans of Europa.” Those insights could be crucial for learning whether the satellite harbors life. Two NASA planetary scientists, Kevin Hand and Robert Carlson, have a lead on the case: the gunk may be simple sea salt, just like that in Earth's oceans but baked by radiation. They came to that ...