Dandelion design
Flight of the plant’s seeds astonishes bioengineers
The fluffy seeds that make dandelions so prolific as weeds also makes them unique in God’s creation. A team of bioengineers recently discovered dandelions use a type of flight scientists have never seen before, according to a study published in the journal Nature last month.
Dandelion seeds dangle from a parachute-like structure called a pappus. Each pappus contains about 100 filaments radiating out from a central point like the spokes of a bicycle wheel. And, like a parachute, the structure of the pappus increases aerodynamic drag, slowing the descent of each seed. But scientists could not figure out how the seeds stay in the air long enough to disperse so far—sometimes traveling for miles.
When other seeds, or even animals and airplanes, take flight, rings of circulating air called vortices form around them and assist propulsion. But scientists did not think vortices could form around a dandelion’s pappus because of how much space was between the spokes. To researchers’ astonishment, they discovered that a vortex materializes and hovers above the pappus without ever coming into contact with it (see video below). The empty spaces between the spokes make it possible for the vortices to materialize. “All falling objects, from feathers to cannon balls, create turbulence in their wake,” the researchers said. “But it takes a rare combination of size, mass, shape, and, crucially, porosity, for the pappus to generate this vortex ring.”
The scientists also found the dandelion seed spokes have the perfect structure to remain airborne. When they constructed silicone models of the pappus and varied the amount of space between spokes, only those that imitated the natural dandelion pappus, which is 92 percent space, could maintain a detached vortex. When the scientists varied the spaces by as little as 10 percent, the vortices destabilized.
In an article in Nature, the editors described this discovery as “an example of how evolution can produce ingenious solutions to the most finicky problems, such as seed dispersal.” Even more puzzling: How a blind, random chance process such as evolution could produce such “ingenious solutions.”
Space: The final business frontier
A private, U.S. aerospace company called Rocket Lab just launched its first commercial mission into orbit. On Sunday, Electron, the company’s 55-foot-tall, two-stage rocket with nine kerosene-burning engines, blasted off from Rocket Lab’s launch complex in New Zealand. The rocket carried six small satellites to collect and transmit data, as well as a drag sail demonstrator. A little more than 11 minutes after liftoff, the rocket released its spacecraft passengers into orbit.
Electron can place up to 330 pounds of payload into polar orbit about 310 miles above Earth and 500 pounds at a lower orbit, Spaceflight Now reported. The engine’s 3-D printed component parts and battery-powered pumps reduce the cost and manufacturing time, making it a feasible option for businesses.
“Our vision at Rocket Lab is to make space commercially viable and more accessible than ever, doing what the Ford Model T did for consumer automobiles,” said Peter Beck, Rocket Lab’s founder and CEO. “This technology will really open space for business.”
The company plans another launch in December to carry around a dozen small scientific and research satellites sponsored by NASA. Rocket Lab plans up to 16 Electron launches in 2019, with a new launch pad in Virginia scheduled to begin operations in the third quarter of next year. —J.B.
New surgery helps children walk again
Acute flaccid myelitis (AFM), a rare, polio-like illness that mainly affects children, has caught media attention recently because of a mysterious spike in the number of cases. Scientists have not yet found a prevention or cure, but some doctors recently reported success helping children afflicted with the disease walk again through a surgical technique called nerve transfer, CBS News reported.
Last year, Amy Moore, a physician with Washington University in St. Louis, performed the first-of-its-kind nerve transfer on an 8-year-old boy, Brandon Noblitt, who lost the use of his legs after contracting AFM. The surgery took a graft from a nerve that allowed the child to wiggle his toes and moved it up to his hip. At a recent follow-up appointment, the boy could walk again. Surgeons at Children’s Hospital in Los Angeles also reported some success with nerve transfer surgery.
Doctors know little about AFM except it often follows a viral illness and causes sudden arm or leg weakness and reflex loss that can leave its victims wheelchair-bound. The disease only strikes about 1 in 1 million people annually, but reported cases spiked in August, with 90 documented in 27 states this year. The Centers for Disease Control and Prevention is planning a special task force to investigate. —J.B.
Healing ozone holes
Good news! The ozone layer is healing, according to a National Oceanic and Atmospheric Administration assessment published this month.
In 1985, scientists discovered that Earth’s ozone, the layer of the atmosphere that shields us from the sun’s dangerous ultraviolet rays, had been thinning since the mid-1970s. Within two years, governments worldwide banned the use of ozone-depleting chemicals in aerosol sprays and coolants.
The thinning reached its peak in the 1990s at about 10 percent depletion. Since then, the ozone layer has increased in thickness by about 1 to 3 percent per decade. According to the report, the ozone layer above the Northern Hemisphere should experience complete healing by the 2030s, an area above the Southern Hemisphere by the middle of the century, and the large hole above the Antarctic in the 2060s.
But some experts still warn that some ozone measurements haven’t increased, and new technology has detected increased emissions of a banned ozone-depleting chemical in East Asia. Also, environmentalists worry that a healed ozone will increase global temperature. —J.B.
Genome sequencing all living organisms
Researchers from the United Kingdom’s Wellcome Sanger Institute announced last week that they plan to sequence the genomes of the country’s 66,000 species of eukaryotic life, or almost all living organisms except some types of bacteria.
The initiative, which they dubbed “The Darwin Tree of Life Project,” is part of an even more ambitious $4.7 billion global effort, the Earth BioGenome Project. Experts working on the EBP plan to sequence the genomes of the world’s 1.5 million species of eukaryotes within the next decade. The EBP is the next “moonshot for biology,” Harris Lewin, the project chair, told Science.
The researchers said the undertaking will benefit agriculture and medicine and assist in biodiversity conservation. So far scientists have sequenced only about 3,500 eukaryotic genomes and only 100 of high quality.
Mike Stratton, the director of the Wellcome Sanger Institute, said the U.K. project will likely cost up to $64 million for the first phase and another $128 million over the next five to seven years. —J.B.
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