Wink Space: A Kaleidoscope in a Shipping Container by Masakazu Shirane and Saya Miyazaki http://bit.ly/WxRomI
Toasted Oatmeal with Strawberry Chia Jam and Coconut Whipped Cream / Recipe
Sweet, salty, sour and bitter — every schoolchild knows these are the building blocks of taste. Our delight in every scrumptious bonbon, every sizzling hot dog, derives in part from the tongue’s ability to recognize and signal just four types of taste.
But are there really just four? Over the last decade, research challenging the notion has been piling up. Today, savory, also called umami, is widely recognized as a basic taste, the fifth. And now other candidates, perhaps as many as 10 or 20, are jockeying for entry into this exclusive club.
“What started off as a challenge to the pantheon of basic tastes has now opened up, so that the whole question is whether taste is even limited to a very small number of primaries,” said Richard D. Mattes, a professor of nutrition science at Purdue University.
Taste plays an intrinsic role as a chemical-sensing system for helping us find what is nutritious (stimulatory) and as a defense against what is poison (aversive). When we put food in our mouths, chemicals slip over taste buds planted into the tongue and palate. As they respond, we are thrilled or repulsed by what we’re eating.
But the body’s reaction may not always be a conscious one. In the late 1980s, in a windowless laboratory at Brooklyn College, the psychologist Anthony Sclafani was investigating the attractive power of sweets. His lab rats loved Polycose, a maltodextrin powder, even preferring it to sugar.
That was puzzling for two reasons: Maltodextrin is rarely found in plants that rats might feed on naturally, and when human subjects tried it, the stuff had no obvious taste.
More than a decade later, a team of exercise scientists discovered that maltodextrin improved athletic performance — even when the tasteless additive was swished around in the mouth and spit back out. Our tongues report nothing; our brains, it seems, sense the incoming energy.
“Maybe people have a taste for Polycose,” Dr. Sclafani said. “They just don’t recognize it consciously, which is quite an intriguing possibility.”
Dr. Sclafani and others are finding evidence that taste receptors on the tongue are also present throughout the intestine, perhaps serving as a kind of unconscious guide to our behavior. These receptors influence the release of hormones that help regulate food intake, and may offer new targets for diabetes treatments, Dr. Sclafani said.
Many tastes are consciously recognized, however, and they are distinguished by having dedicated sets of receptor cells. Fifteen years ago, molecular biologists began figuring out which of these cells in the mouth elicit bitter and sweet tastes.
By “knocking out” the genes that encode for sweet receptors, they produced mice that appeared less likely to lap from sweet-tasting bottles. Eventually, the putative receptors for salty and sour also were identified.
In 2002, though, as taste receptors were identified, the evidence largely confirmed the existence of one that scientist had been arguing about for years: savory.
Umami is subtle, but it is generally described as the rich, meaty taste associated with chicken broth, cured meats, fish, cheeses, mushrooms, cooked tomatoes and seaweed. Some experts believe it may have evolved as an imperfect surrogate for detecting protein.
Since then, researchers have proposed new receptor cells on the tongue for detecting calcium, water and carbonation. The growing list of putative tastes now includes soapiness, lysine, electric, alkaline, hydroxide and metallic.
“The taste field has been absolutely revolutionized,” said Michael Tordoff, a biologist at the Monell Chemical Senses Center. “We’ve made more progress in the last 15 years than in the previous 100.”
One candidate for the next basic taste appears to have emerged as the front-runner: fattiness. The idea has been around for a while, and many scientists thought it was not a specific taste, more like a texture or an aroma.
But researchers recently identified two taste receptors for unsaturated fats on the tongue. And fat evokes a physiological response, Dr. Mattes has found that blood levels of fat rise when we put dietary fat in our mouths, even without swallowing or digesting it.
Hours after a meal, the taste of fatty acids alone can elevate triglyceride levels, even when the nose is plugged. But fat, like umami, does not have a clear, perceptible sensation, and it is hard to distinguish a texture from a taste.
Dr. Mattes says that fat may have a texture that we like (rich and gooey) and a taste that we don’t (rancid).
If so, the taste may serve as part of our sensory alert system. When food spoils, he notes, it often contains high levels of fatty acids, and the taste of them may be “a warning signal.”
Although there is still no consensus beyond sweet, salty, sour, bitter and savory, the research makes clear there is more to taste than a handful of discrete sensations on the tongue. Before long, scientists may have to give up altogether on the idea that there are just a few basic tastes.
“If you’re talking three, four, five, six, you can still call it a pretty exclusive club,” Dr. Mattes said. “If you start getting beyond that, is the concept really useful?”
So delicate Flowergirls by Lim Zhi Wei / Love Limzy, Malaysian artist.
these are amazing
How to read math. You’d be surprised how far this will get you.
[Isn’t the last one “for all integers a and b there exists a unique positive integer k such that …..”? I think maybe you meant to not have the superscript +?]
I think there was supposed to be a plus, and that it was supposed to have your correction. In any case, it is false: there is no gcd(0, 0). Other than that edge case, though, all GCDs are positive.
Similarly, the subset sign used in saying the reals are a subset of the reals usually means “proper subset”, which is a non-equal subset; this is clearly false. The one used in the glossary part means any subset and would have worked. Think of the difference between the less-than sign (<) and the less-than-or-equal-to sign (≤): the bar means the same thing in both cases.
EDIT TO ADD: Still very good and gets the main points across nicely.
EDIT: Tumblr ate some of my post and formatting because I didn’t realize I was in the HTML editor mode. I fixed them.
daniel-r-h has some good points.
- The first statement is not a true statement (which is my bad). However, it is almost translated correctly (I believe). As transgeometer points out, there’s something going on with the superscript and the positivity of k. I intended the superscript because the gcd should be positive, but failed to translate it properly and say a “unique positive integer k.”
- The second point about the subsets is also technically correct, but… the translation is still correct in a way too. Notice how the glossary symbol for “subset of” has a line under where as the example does not. Some mathematicians interpret there being no line under the symbol as meaning the set has to be a proper subset, meaning the subset cannot be the entire set. However, there are many mathematicians that use both symbols interchangeably. When they want to indicate that they are looking at proper subsets, they use another symbol which has a line with a slash through it. I think it’s important to be told this because until someone does, you can ask the kind of questions that daniel-r-h did about proper and not proper subsets, when the writer is just using their preference of subset symbol. I’ll admit it was a mistake when I typed it up though (\subset and \subsetneq)
Thank you for pointing out these mistakes though! You’re better mathematicians than me
Found this guy on the hood of my car, about the size of a hornet, in central WI, USA.
Wow, great find! You found yourself a Wasp Mantidfly (Climaciella brunnea). Despite its common name this guy is neither a wasp or a mantis (or a fly) and is actually closely related to lacewings and their allies.
Oh and also this guy is totally harmless he’s just mimicking a wasp and cannot sting.
What movies made you feel especially like this? A lot of people are saying Lucy, but remember when NDT was pretty upset about Gravity?
Mudskipper is a fish which spend more time on land than in water. In fact, a mudskipper will drown if it’s never able to reach the water’s surface! Like other fish, mudskippers breathe through gills, but in addition they absorb oxygen through their skin and the linings of their mouths and throats. They are able to move over land by using their pectoral fins to pull themselves forward, or they perform a series of skips or jumps. Pokemon “Mudkip” is based on this fish.
And what about those funky eyes??