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Monday, September 17, 2007Cats Cannot Taste Sweets
There is a reason cats prefer meaty wet food to dry kibble, and disdain sugar entirely.
Sugar and spice and everything nice hold no interest for a cat. Our feline friends are only interested in one thing: meat (except for saving up the energy to catch it by napping, or a round of restorative petting) This is not just because inside every domestic tabby lurks a killer just waiting to catch a bird or torture a mouse, it is also because cats lack the ability to taste sweetness, unlike every other mammal examined to date.
The tongues of most mammals hold taste receptors—proteins on the cellular surface that bind to an incoming substance, activating the cell's internal workings that lead to a signal being sent to the brain. Humans enjoy five kinds of taste buds (possibly six): sour, bitter, salty, umami (or meatiness) and sweet (as well as possibly fat). The sweet receptor is actually made up of two coupled proteins generated by two separate genes: known as Tas1r2 and Tas1r3.
When working properly, the two genes form the coupled protein and when something sweet enters the mouth the news is rushed to the brain, primarily because sweetness is a sign of rich carbohydrates—an important food source for plant-eaters and the nondiscriminating, like humans. But cats are from the noble lineage Carnivora and, unlike some of its lesser members, such as omnivorous bears or, even more appalling, herbivorous pandas, they exclusively eat meat.
Whether as a result of this dietary choice or the cause of it, all cats—lions, tigers and British longhairs, oh my—lack 247 base pairs of the amino acids that make up the DNA of the Tas1r2 gene. As a result, it does not code for the proper protein, it does not merit the name gene (only pseudogene), and it does not permit cats to taste sweets. "They don't taste sweet the way we do," says Joe Brand, biochemist and associate director at the Monell Chemical Senses Center in Philadelphia. "They're lucky. Cats really have bad teeth as it is."
Brand and his colleague Xia Li first discovered the pseudogene after decades of anecdotal evidencesuch as cats showing no preference between sweetened and regular water, unlike other animals—testifying to their indifference to the sweet stuff. Of course, there are also plenty of anecdotal accounts pointing in the other direction: cats that eat ice cream, relish cotton candy, chase marshmallows. "Maybe some cats can use their [Tas1r3 receptor] to taste high concentrations of sugar," Brand says. "It's a very rare thing but we don't know yet."
Scientists do know, however, that cats can taste things we cannot, such as adenosine triphosphate (ATP), the compound that supplies the energy in every living cell. "There isn't a lot hanging around in meat, but it's a signal for meat," Brand says. And plenty of other animals have a different array of receptors, Li says, from chickens that also lack the sweet gene to catfish that can detect amino acids in water at nanomolar concentrations. "Their receptor is more sensitive than the background concentration," Brand notes. "The catfish that detects the rotting food first is the one that survives."
So far, cats are alone among mammals in lacking the sweet gene; even close relatives among the meat-eaters like hyenas and mongooses have it. And cats may lack other components of the ability to enjoy (and digest) sugars, such as glucokinase in their livers—a key enzyme that controls the metabolism of carbohydrates and prevents glucose from flooding the animal. Despite this, most major pet food manufacturers use corn or other grains in their meals. "This may be why cats are getting diabetes," Brand offers. "Cat food today has around 20 percent carbohydrates. The cats are not used to that, they can't handle it." What these fearsome predators of suburbia cannot taste may be hurting them. But it also means that most cat lovers don't have to worry about Simon snatching their unattended dessert.
Is the so-called "Mozart effect" a scientifically supported, developmental leg up or a media-fueled "scientific legend"?
The phrase "Mozart Effect" conjures an image of a pregnant woman who, sporting headphones over her belly, is convinced that playing classical music to her unborn child will improve the tyke's intelligence. But is there science to back up this idea, which has spawned a cottage industry of books, CDs and videos?
A short paper published in Nature in 1993 unwittingly introduced the supposed Mozart effect to the masses. Psychologist Frances Rauscher's study involved 36 college kids who listened to either 10 minutes of a Mozart sonata in D-major, a relaxation track or silence before performing several spatial reasoning tasks. In one test—determining what a paper folded several times over and then cut might look like when unfolded—students who had listened to Mozart seemed to show significant improvement in their performance (by about eight to nine spatial IQ points).
Rauscher—whose work, unlike most scientists, is sometimes cited on the liner notes of CDs—remains puzzled as to how this narrow effect of classical music extended from a paper-folding task to general intelligence and from college students to children (and fetuses). "I think parents are very desperate to give their own children every single enhancement that they can," she surmises.
In addition to a flood of commercial products in the wake of the finding, in 1998 then-Georgia governor Zell Miller mandated that mothers of newborns in the state be given classical music CDs. And in Florida, day care centers were required to pipe symphonies through their sound systems.
A 2004 Stanford study tracked the media's coverage of Rauscher's study relative to other studies published in Nature around the same period. In the U.S.'s top 50 newspapers, her paper, titled "Musical and Spatial Task Performance," was cited 8.3 times more often than the second-most popular paper (co-authored by famed astronomer Carl Sagan).
"It seems to be a circumscribed manifestation of a widespread, older belief that has been labeled 'infant determinism,' the idea that a critical period early in development has irreversible consequences for the rest of a child's life," the researchers wrote in their analysis. "It is also anchored in older beliefs in the beneficial powers of music."
Some still argue for such musical powers. "Music has a tremendous organizing quality to the brain," notes Don Campbell, a classical musician who has written more than 20 books on music, health and education, including The Mozart Effect® and The Mozart Effect® for Children. Referencing French physician Alfred Tomatis's work in music therapy on children with dyslexia, attention-deficit disorders and autism in the mid-20th century, he believes music that's not highly emotional or overly rhythmic has a multilayered influence on the individual, from modulating mood to alleviating stress. "I know it improves our ability to be intelligent," he adds.
But in 1999 psychologist Christopher Chabris, now at Union College in Schenectady, N.Y., performed a meta-analysis on 16 studies related to the Mozart effect to survey its overall effectiveness. "The effect is only one and a half IQ points, and it's only confined to this paper-folding task," Chabris says. He notes that the improvement could simply be a result of the natural variability a person experiences between two test sittings.
Earlier this year, the Federal Ministry of Education and Research in Germany published a second review study from a cross-disciplinary team of musically inclined scientists who declared the phenomenon nonexistent. "I would simply say that there is no compelling evidence that children who listen to classical music are going to have any improvement in cognitive abilities," adds Rauscher, now an associate professor of psychology at the University of Wisconsin–Oshkosh. "It's really a myth, in my humble opinion."
Read More at:http://www.sciam.com/article.cfm?chanID=sa029&articleID=FBB1ABAE-E7F2-99DF-3C2FEE4066F9308B&pageNumber=2&catID=9
British scientists say early humans almost certainly walked upright on two legs, but evidence suggests they couldn't run very fast.
Bill Sellers of the University of Manchester, who led the study, said if early humans lacked an Achilles tendon, as modern chimps and gorillas do, their ability to run would have been severely compromised.
"Our research supports the belief that the earliest humans used efficient bipedal walking rather than chimp-like 'Groucho' walking," said Sellers. "But if, as seems likely, early humans lacked an Achilles tendon then whilst their ability to walk would be largely unaffected, our work suggests running effectiveness would be greatly reduced with top speeds halved and energy costs more than doubled."
Sellers said "efficient running" would have been necessary for human ancestors to "move from a largely herbivorous diet to the much more familiar hunting activities associated with later humans."
"What we need to discover now is when in our evolution did we develop an Achilles tendon, as knowing this will help unravel the mystery of our origins."
Sellers presented the research Tuesday during the British Association for the Advancement of Science "Festival of Science" at the University of York.
THE kiss you share with the exquisite stranger is electric, deep and seemingly endless — that is until you open an eye and see drool on your pillow.
If only you could have slept long enough to consummate the seduction. Then again, you had no idea you were dreaming. Besides, you cannot control the nightly ride on the wings of your subconscious. Or can you?
Maybe, if you learn to practice “lucid dreaming,” a state in which a sleeping person becomes aware he or she is dreaming and may even be able to direct the action. Those who regularly experience the phenomenon say that like the physics-defying characters in “The Matrix,” they are able to generate or manipulate the fantastical events that unfold. They can fly without wings, play instruments they never learned, go bowling with T. S. Eliot — and, yes, indulge sexual fantasies.
It is likely some people have always had such dreams, said Jayne Gackenbach, a professor of psychology at Grant MacEwan College in Edmonton, Alberta, who conducts research into lucid dreaming. But the esoteric practice, which has been acknowledged in the West since at least 1867, seems on the verge of becoming much better known.
A film exploring its allure, “The Good Night,” written and directed by Jake Paltrow and starring his sister, Gwyneth, Penélope Cruz and Martin Freeman, is opening Oct. 5. Depressed by his waking life, the film’s main character is determined to master the art of lucid dreaming to escape to an inspiring, sensual unreality with a lacquer-lipped knockout. “What I find myself most attracted to are things that can actually occur,” Mr. Paltrow said in an interview. “There’s really nothing in this movie that couldn’t happen.”
For those wishing to become lucid dreamers, a nine-and-a-half-day instructional retreat, “Dreaming and Awakening: Lucid Dreaming, Consciousness and Dream Yoga,” is scheduled to begin Oct. 1 in Hawaii. Don’t want to pay the airfare? On Oct. 3, an online chat about lucid dreaming takes place, part of the PsiberDreaming conference of the International Association for the Study of Dreams. There are new and soon-to-be published books, like “Lucid Dreaming for Beginners: Simple Techniques for Creating Interactive Dreams” (Llewellyn Publications) and “Between the Gates: Lucid Dreaming, Astral Projection and the Body of Light in Western Esotericism” (Weiser Books).
“It has gone from this very obscure type of dream to being discussed at the various dream and consciousness conferences,” Dr. Gackenbach said.
But it is not only dream experts discussing the topic. Two filmmakers described their lucid dreaming earlier this year. Michel Gondry, who directed “Eternal Sunshine of the Spotless Mind,” described for The Guardian lucid dreams in which “I generally end up having sex with the first girl I can find.” Guillermo del Toro, the director of “Pan’s Labyrinth,” mentioned his lucid dreaming on the National Public Radio program “Fresh Air.” “Pan’s Labyrinth” brings to life a twiggy mythological creature (a faun) he encountered in lucid dreams as a boy; the film won an Oscar this year for its surrealistic makeup.
Other films, including “Waking Life” and “Vanilla Sky,” have woven lucid dreaming into their plots. So have television series like “Alias,” “Star Trek” and “Ed” (Daryl Hall and John Oates make an appearance in Ed’s dream). Novelists including Stephen King, William Boyd and Graham Joyce have written about lucid dreaming, and the Verve, a British rock band, sang about it in “Catching the Butterfly.”
“Lucid dream” is the name of pop and jazz CDs, small businesses, modern artworks, even a sex toy.
Still, many people have never heard of it. Established sleep researchers say lucid dreaming is occasionally reported by subjects, though it is difficult to validate scientifically. “Yes, lucid dreaming exists,” said Dr. Rodney Radtke, the medical director of the Sleep Disorders Center at Duke University. “Yes, people certainly can, within their dream, realize ‘this is just a dream’ and continue to participate.”
“Do I believe that someone could potentially alter or interact with their dreams in such a way that they could change the dream? Yes,” he said. “Do I think that you could essentially design a dream — ‘Oh, I want to go to Honolulu and have this big hunk hit on me’? It’s a bit of a stretch. But I can’t say it can’t happen.”
He added: “Only in New York or California do they worry about this stuff.”
Stephen LaBerge, a psychophysiologist and the founder of the Lucidity Institute (lucidity.com), conducts lucid dream research and teaches people to do it.
“It’s kind of fun to do the impossible,” Dr. LaBerge said. “Fly. Dream sex. That’s what everybody likes to do. There’s also the possibility of creative problem-solving, overcoming nightmares and anxieties, learning more about yourself.”
A student at Stanford University, where Dr. LaBerge conducted much of his research, wrote in The Stanford Daily: “In one of my earliest experiences with lucidity, I announced to an auditorium full of people that I was their god (wasn’t I?). When they did not respond deferentially, I used telekinesis to send one of them flying across the room.”
It can be particularly appealing to those who have nightmares, as it allows them to realize while still asleep that they are just dreaming.
More than 5 million teeth are knocked out every year in children and adults. With proper emergency action, a tooth that has been knocked out of its socket can be successfully replanted and last for years!
If your child or friends has a permanent tooth knocked out, it should be considered a dental emergency, the Nemours Foundation advises.
The tooth is most likely to survive if it is properly placed back in the socket within 30 minutes of the injury.
Here are the foundation’s suggestions for what to do if a child’s permanent tooth is knocked out:
Find the tooth, and only handle it by the crown (the part that you’d see in a person’s mouth), never by the root.
Immediately rinse the tooth (don’t scrub it) with saline solution or milk. Don’t use tap water, which typically contains chlorine, unless that’s all that’s available.
If your child is old enough to hold it there, place the tooth gently back in its socket.
If your child is young, store the tooth in a cup of milk, or hold it in your mouth between your cheek and lower gum.
Go immediately to your dentist or local emergency room.
Read More at:http://www.health-sky.com/html/tips-for-saving-a-knocked-out-tooth-time-is-of-the-essence.html