Pentaquarks, locked-in syndrome and more reader feedback
Behold the pentaquark
Quarks, the building blocks of protons and neutrons, travel in packs. Researchers at the Large Hadron Collider near Geneva caught a glimpse of two new five-quark particles, Andrew Grant wrote in “LHC reports pentaquark sightings” (SN: 8/8/15, p. 8).
“In the story, particle physicists at the LHC report that a pentaquark contains a charm quark and its antimatter counterpart,” Terry Breen wrote in an e-mail. “Doesn’t the theory of matter call for a particle and its antimatter counterpart to immediately annihilate each other?”
The discovered pentaquarks exist for only a little more than a trillionth of a trillionth of a second before decaying into other particles, Grant says. As for why they don’t annihilate themselves before that, a few factors are at play.
First, the charm and anticharm quarks may not be right next to each other within the pentaquark. Also, in addition to having flavor — charm, strange, up, down, bottom or top — quarks also have a property called color, though it has nothing to do with the colors of the rainbow. If the colors of the charm and anticharm don’t correspond, they take longer to annihilate.
Delightful diatoms
After seeing Sarah Schwartz’s “Encased algae create kaleidoscope of color” (SN: 8/8/15, p. 32), reader John Turner pointed out that diatom arrangements are part of a long tradition. “Amateur naturalists in Victorian times collected diatoms the way we today collect seashells and then would proudly show off their collections (under microscopes) to guests,” he wrote.
Detecting consciousness
In “Locked inside” (SN: 8/8/15, p. 18), Laura Beil relates the story of a man who, before regaining the ability to move and communicate with his eyes, lived for 12 years mentally aware but unable to interact. “Scientists assume that stories like these, astonishing as they are, represent only a small fraction of patients,” Beil wrote in her story exploring how scientists are learning to communicate with locked-in patients.
Brian Quass took issue with the assumption about the low fraction. “For scientists to claim that such incidents are rare at this early point in the investigation (after all, locked-in syndrome has scarcely been discovered) strikes me as a mixture of defensiveness and wishful thinking,” he wrote.
Neuroscientist Damien Gabriel of the University Hospital of Besançon in France replies that there are “strong clues” that most vegetative patients are not conscious, including that many patients lack even elementary reflexes. “In this case, chances of having preserved cognitive abilities are extremely poor,” he says.
Another indicator is the severity of brain damage. “More than half of the brain is sometimes missing,” he says. Neuroscientist Srivas Chennu of the University of Cambridge agrees that science still has a lot to learn about vegetative patients: “Exactly which parts and functions of the brain are important for consciousness is indeed a fascinating question, and a topic of current research.”
A snake with legs
A four-legged snake fossil may demonstrate the evolution of snakes from lizardlike ancestors, Meghan Rosen reported in “Snake fossil with four limbs found” (SN: 8/22/15, p. 10).
Readers wondered about the animal’s actual identity. “If it’s not a snake, does this mean there was some other long, slinky, multiribbed species that just happened to resemble a snake?” asked Mark S., noting that many of today’s lizard species actually lack legs. Another reader, hschulsinger, wondered if the fossil might even be a hoax: “The ‘legs’ are too far apart to have been of any use to this creature.”
The fossil may not have been a snake or even a reptile, Michael Caldwell, a paleontologist at the University of Alberta in Canada, told Rosen. “There are buckets of vertebrates out there that are long and skinny,” he says. The animal could have been an amphibian, for example. Scientists have found lots of bizarre-looking ancient creatures, he says.
And although the animal’s tiny limbs may not have been for walking, they could have helped it seize prey or grasp onto mates, the study’s authors suggest.
