Teen songs really do have more meaning
Why do the songs I heard when I was teenager sound sweeter than anything I listen to as an adult? I'm happy to report that my own failures of discernment as a music critic may not be entirely to blame. In recent years, psychologists and neuroscientists have confirmed that these songs hold disproportionate power over our emotions. And researchers have uncovered evidence that suggests our brains bind us to the music we heard as teenagers more tightly than anything we'll hear as adults — a connection that doesn't weaken as we age. Musical nostalgia, in other words, isn't just a cultural phenomenon: It's a neuronic command. And no matter how sophisticated our tastes might otherwise grow to be, our brains may stay jammed on those songs we obsessed over during the high drama of adolescence.
Mark Joseph Stern, Slate
Dogs have great smell but lack taste
Q: Dogs have such exquisite olfactory abilities; do they also possess a superior ability to taste things?
A: Their sense of smell may outweigh their sense of taste.
Dogs indeed have 60 times as many smell receptors as humans do, said Dr. Ann Hohenhaus of the Animal Medical Center in New York, and they have 40 times as much brainpower dedicated to smell, allowing them to differentiate 30,000 to 100,000 aromas. "Thus, in dogs," she said, "smell is likely the driving force behind food preferences and at least part of the reason dogs wolf down their food without savoring a bite." She added that dogs have about 1,700 taste buds, compared with about 9,000 in humans. "While it has been reported that dogs possess taste receptors for salt, sweet, bitter and sour," Hohenhaus said, "dogs generally prefer meat or meat-flavored foods."
C. Claiborne Ray, New York Times
The pH of how spiders spin liquid steel
For its size, spider silk is stronger than steel, yet it is extraordinarily lightweight and stretchy. Now scientists are learning how spiders produce it. It was already known that spiders store silk proteins, called spidroins, in their glands. But how they converted these soluble, gel-like proteins into a solid state has been a mystery.
Researchers from Sweden report that the change to solid is brought about by a change in pH that occurs as the proteins travel through the glands. The findings appear in the journal PLOS Biology.
"Going from this soluble state is very important because, otherwise, the silk gland would get clogged," said an author of the study, Dr. Jan Johansson, a medical biochemist at the Swedish University of Agricultural Sciences.
"Now that we know how the spider does it, we can hopefully also make a mimic," said another author, Anna Rising, a veterinary scientist at the university. "If we could produce large amounts at a low price, there's no limit to what it could be used for."
Sindya N. Bhanoo, New York Times
How dinosaurs got small to take wing
How did birds emerge from a lineage of large dinosaurs whose clawed feet were planted firmly on the ground? Size really matters, according to a team of scientists that traced the incredibly fast shrinkage along 50 million years of ancient avian evolution.
The findings, published in the journal Science, show how the continuous miniaturization of this dinosaur lineage allowed for a whole host of physical changes that made powered flight possible.
Paleontologists have long known that birds evolved from dinosaurs known as theropods, a group that included the formidable Tyrannosaurus rex. And scientists now have found that in the last 50 million years or so before Archaeopteryx (the first known bird) took flight, dinosaurs in the line leading to birds shrunk 12 times, from an average of 359 pounds to a mere 1.8 pounds. And not only that: Miniaturization is also linked to a shortened development period, which means that the increasingly tiny dinosaurs would hold onto more "juvenile" traits in adulthood — shorter snouts, smaller teeth, bigger eyes and bigger brains — some of which were uncannily bird-like traits.
Why the push toward smaller and smaller animals? It could be that the dinosaurs were adapting to living in trees. For arboreal life, you need a small body, big eyes for good 3-D vision so you don't ram yourself into a tree while you're hopping from branch to branch, big brains to deal with a complex environment, and insulating feathers so you can operate at night and munch on nocturnal insects. That's not to mention longer forelimbs to go from tree to tree, which might eventually develop a wing-like surface area to help glide.
Amina Khan, Los Angeles Times
A fist bump to fight bacteria
Weak handshakes are often frowned upon, but they may be healthier than firm ones. A fist bump, though, may be an even more hygienic choice. British researchers did a simple experiment. After dipping a gloved hand into a dense culture of Escherichia coli, a bacterium commonly found in human intestines, an experimenter shook hands, bumped fists or high-fived with a person wearing a sterile glove. The results were published in the August issue of the American Journal of Infection Control.
About twice as many bacteria were transferred to the clean glove with a handshake as with a high-five, and the fist bump consistently produced the lowest transmission of all. They then did the fist bump and high-five tests with three more seconds of contact, and tested various pressures and durations for the handshake. Prolonging the high-five had little effect, but making the fist bump three seconds longer significantly increased the transfer of bacteria. A strong handshake (as measured with a dynamometer) was especially effective, moving germs hand to hand in almost twice the quantities of a moderate handshake. Hand hygiene is a serious problem in hospitals, and a recent editorial in JAMA suggested that handshakes should be banned in health care facilities.
Nicholas Bakalar, New York Times