Chapter 9. Hearing, Vestibular Perception, Taste, and Smell

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By NICHOLAS BAKALAR Obesity in adolescents is associated with a range of cardiovascular and other health risks. Now a new study adds one more: hearing loss. Several studies have demonstrated the association of obesity with hearing loss in adults, but now researchers examining records of a nationwide sample of 1,488 boys and girls ages 12 to 19 have found the same association in teenagers. The study appeared online in The Laryngoscope. The researchers controlled for various factors, including poverty, sex, race and previous exposure to loud noises. They found that being at or above the 95th percentile for body mass index — the definition of obesity in teenagers — was independently associated with poorer hearing over all frequencies, and with almost double the risk of low-frequency hearing loss in one ear. They suggest that this may represent an early stage of injury that will later progress to both ears, as it does in adults. The reason for the connection is not known, but the scientists suggest that inflammation induced by obesity may be a factor in organ damage. “It’s quite possible that early intervention could arrest the progression,” said the lead author, Dr. Anil K. Lalwani, a professor of otolaryngology at Columbia University. “This is another reason to lose weight — but not to lose hope.” Copyright 2013 The New York Times Company

Keyword: Obesity; Aggression
Link ID: 18287 - Posted: 06.20.2013

By NICHOLAS BAKALAR Hearing loss in older adults increases the risk for hospitalization and poor health, a new study has found, even taking into account other risk factors. Researchers analyzed data on 529 men and women over 70 with normal hearing, comparing them with 1,140 whose hearing was impaired, most with mild or moderate hearing loss. The data were gathered in a large national health survey in 2005-6 and again in 2009-10. The results appeared in The Journal of the American Medical Association. After adjusting for race, sex, education, hypertension, diabetes, stroke, cardiovascular disease and other risks, the researchers found that people with poor hearing were 32 percent more likely to be hospitalized, 36 percent more likely to report poor physical health and 57 percent more likely to report poor emotional or mental health. The authors acknowledge that this is an association only, and that there may be unknown factors that could have affected the result. “There has been a belief that hearing loss is an inconsequential part of aging,” said the lead author, Dr. Frank R. Lin, an associate professor of otolaryngology at Johns Hopkins. “But it’s probably not. Everyone knows someone with hearing loss, and as we think about health costs, we have to take its effects into account.” Copyright 2013 The New York Times Company

Keyword: Hearing
Link ID: 18267 - Posted: 06.13.2013

A team of NIH-supported researchers is the first to show, in mice, an unexpected two-step process that happens during the growth and regeneration of inner ear tip links. Tip links are extracellular tethers that link stereocilia, the tiny sensory projections on inner ear hair cells that convert sound into electrical signals, and play a key role in hearing. The discovery offers a possible mechanism for potential interventions that could preserve hearing in people whose hearing loss is caused by genetic disorders related to tip link dysfunction. The work was supported by the National Institute on Deafness and Other Communication Disorders (NIDCD), a component of the National Institutes of Health. Stereocilia are bundles of bristly projections that extend from the tops of sensory cells, called hair cells, in the inner ear. Each stereocilia bundle is arranged in three neat rows that rise from lowest to highest like stair steps. Tip links are tiny thread-like strands that link the tip of a shorter stereocilium to the side of the taller one behind it. When sound vibrations enter the inner ear, the stereocilia, connected by the tip links, all lean to the same side and open special channels, called mechanotransduction channels. These pore-like openings allow potassium and calcium ions to enter the hair cell and kick off an electrical signal that eventually travels to the brain where it is interpreted as sound. The findings build on a number of recent discoveries in laboratories at NIDCD and elsewhere that have carefully plotted the structure and function of tip links and the proteins that comprise them. Earlier studies had shown that tip links are made up of two proteins — cadherin-23 (CDH23) and protocadherin-15 (PCDH15) — that join to make the link, with PCDH15 at the bottom of the tip link at the site of the mechanotransduction channel, and CDH23 on the upper end. Scientists assumed that the assembly was static and stable once the two proteins bonded.

Keyword: Hearing
Link ID: 18265 - Posted: 06.13.2013

By ROBERT J. ZATORRE and VALORIE N. SALIMPOOR MUSIC is not tangible. You can’t eat it, drink it or mate with it. It doesn’t protect against the rain, wind or cold. It doesn’t vanquish predators or mend broken bones. And yet humans have always prized music — or well beyond prized, loved it. In the modern age we spend great sums of money to attend concerts, download music files, play instruments and listen to our favorite artists whether we’re in a subway or salon. But even in Paleolithic times, people invested significant time and effort to create music, as the discovery of flutes carved from animal bones would suggest. So why does this thingless “thing” — at its core, a mere sequence of sounds — hold such potentially enormous intrinsic value? The quick and easy explanation is that music brings a unique pleasure to humans. Of course, that still leaves the question of why. But for that, neuroscience is starting to provide some answers. More than a decade ago, our research team used brain imaging to show that music that people described as highly emotional engaged the reward system deep in their brains — activating subcortical nuclei known to be important in reward, motivation and emotion. Subsequently we found that listening to what might be called “peak emotional moments” in music — that moment when you feel a “chill” of pleasure to a musical passage — causes the release of the neurotransmitter dopamine, an essential signaling molecule in the brain. When pleasurable music is heard, dopamine is released in the striatum — an ancient part of the brain found in other vertebrates as well — which is known to respond to naturally rewarding stimuli like food and sex and which is artificially targeted by drugs like cocaine and amphetamine. © 2013 The New York Times Company

Keyword: Hearing
Link ID: 18251 - Posted: 06.10.2013

by Kim Krieger The song of the cicada has been romanticized in mariachi music, used to signify summer in Japanese cinematography, and cursed by many an American suburbanite wishing for peace and quiet. Despite the bugs' ubiquity, scientists haven't uncovered how they sing so loudly—some are as noisy as a jet engine—and why they don't expend much energy doing it. But researchers reported in Montreal yesterday at the 21st International Congress on Acoustics that they now have the answer. The detailed mechanism of the cicada's song is far from fully understood, says Paulo Fonseca, an animal acoustician at the University of Lisbon who was not involved in the project. The work by the researchers "is innovative and paves our way to a better understanding of this complex system allowing such small animals to produce such powerful sound." Cicadas aren't just a natural curiosity. Small devices that produce extremely loud noises while requiring very little power appeal to the U.S. Navy, which uses sonar for underwater exploration and communication. Derke Hughes, a research engineer at the Naval Undersea Warfare Center in Newport, Rhode Island, says that the loudest cicadas can make a noise 20 to 40 dB louder than the compact off-the-shelf RadioShack speaker in his office using the same amount of power. Intrigued, he and his colleagues used microcomputed tomography)—a kind of CT scan that picks up details as small as a micron in size—to image a cicada's tymbal, which helps the insect make its deafening chirp. © 2010 American Association for the Advancement of Science

Keyword: Hearing; Aggression
Link ID: 18234 - Posted: 06.05.2013

By Susan Milius Cockroaches that don’t fall for traps’ sweet poisons have evolved taste cells that register sugar as bitter. In certain groups of the widespread German cockroach (Blattella germanica), nerve cells that normally detect bitter, potentially toxic compounds now also respond to glucose, says entomologist Coby Schal of North Carolina State University in Raleigh. The “bitter” reaction suppresses the “sweet” response from other nerve cells, and the roach stops eating, Schal and his colleagues report in the May 24 Science. Normally roaches love sugar. But with these populations, a dab of jelly with glucose in it makes them “jump back,” Schal says. “The response is: ‘Yuck! Terrible!’” This quirk of roach taste explains why glucose-baited poison traps stopped working among certain roaches, Schal says. Such bait traps combining a pesticide with something delicious became popular during the mid-1980s. But in 1993, Jules Silverman, also a coauthor on the new paper, reported roaches avoiding these once-appealing baits. “This is a fascinating piece of work because it shows how quickly, and how simply, the sense of taste can evolve,” says neurobiologist Richard Benton of the University of Lausanne in Switzerland. What pest-control manufacturers put in their roach baits now, and whether some still use glucose, isn’t public, Schal says. But humankind’s arms race with cockroaches could have started long ago, “in the caves,” he says. In this back-and-forth struggle, it’s important “to understand what the cockroach is doing from a molecular basis.” © Society for Science & the Public 2000 - 2013

Keyword: Chemical Senses (Smell & Taste); Aggression
Link ID: 18193 - Posted: 05.25.2013

By JANE E. BRODY Sugar, and especially the high-fructose corn syrup that sweetens many processed foods and nearly all soft drinks, has been justly demonized for adding nutritionally empty calories to our diet and causing metabolic disruptions linked to a variety of diseases. But a closer look at what and how Americans eat suggests that simply focusing on sugar will do little to quell the rising epidemic of obesity. This is a multifaceted problem with deep historical roots, and we are doing too little about many of its causes. More than a third of American adults and nearly one child in five are now obese, according to the Centers for Disease Control and Prevention. Our failure to curtail this epidemic is certain to exact unprecedented tolls on health and increase the cost of medical care. Effective measures to achieve a turnaround require a clearer understanding of the forces that created the problem and continue to perpetuate it. The increase in obesity began nearly half a century ago with a rise in calories consumed daily and a decline in meals prepared and eaten at home. According to the Department of Agriculture, in 1970 the food supply provided 2,086 calories per person per day, on average. By 2010, this amount had risen to 2,534 calories, an increase of more than 20 percent. Consuming an extra 448 calories each day could add nearly 50 pounds to the average adult in a year. Sugar, it turns out, is a minor player in the rise. More than half of the added calories — 242 a day — have come from fats and oils, and another 167 calories from flour and cereal. Sugar accounts for only 35 of the added daily calories. Copyright 2013 The New York Times Company

Keyword: Obesity; Aggression
Link ID: 18173 - Posted: 05.20.2013

By Laura Beil When chemists Richard Marshall and Earl Kooi started fiddling with cornstarch, the powder made from the dense insides of corn kernels, their intention was to turn glucose, which is easily produced from the starch, into fructose, which is sweeter. The idea wasn’t that far-fetched. The two sugar molecules are cousins, both made from the same atomic parts slightly rearranged. The duo’s experiment, which took place at the Corn Projects Refining Company in Argo, Ill., was a success. Marshall and Kooi discovered that the bacterium Aeromonas hydrophila produced an enzyme that could reconfigure the components of glucose from corn like so many Lego blocks. It was the first leap forward for a food industry dream: a mass-produced glucose-fructose-blend sweetener that would free commercial food manufacturers from the historical volatility of cane sugar crops. The scientists announced their triumph in a short report in Science in 1957. There the discovery sat in quiet obscurity for almost two decades, until a worldwide spike in sugar prices sent manufacturers scrambling. By the end of the 1980s, high fructose corn syrup had replaced cane sugar in soft drinks, and it soon became popular among makers of baked goods, dairy products, sauces and other foods. Few consumers seemed to care until 2004, when Barry Popkin, a nutrition scientist at the University of North Carolina at Chapel Hill, along with George Bray, at the Pennington Biomedical Research Center in Baton Rouge, La., published a commentary in the American Journal of Clinical Nutrition pointing out that the country’s obesity crisis appeared to rise in tandem with the embrace of high fructose corn syrup by food producers. That shift began in the early 1970s — just about the time Japanese researchers, who had noted Marshall and Kooi’s experiment with keen interest, overcame the technical hurdles of industrial production. © Society for Science & the Public 2000 - 2013

Keyword: Obesity; Aggression
Link ID: 18172 - Posted: 05.20.2013

by Meera Senthilingam Malaria parasites give mosquitoes a keener sense of smell, it seems. A small-scale study in the lab finds that mosquitoes infected by the parasite are three times as likely as uninfected mosquitoes to respond to human odours. If the same results are seen in malaria-carrying mosquitoes in the wild, it could lead to new ways to combat the disease. Female anopheles mosquitoes are attracted to the chemicals in human odours, which help them find the source of blood they need to grow their eggs. When these mosquitoes carry Plasmodium falciparum – the most lethal form of malaria parasite – the likelihood that they will target humans rises. "We knew already that mosquitoes bite more often when they're infected. They probe the skin more frequently," says James Logan from the London School of Hygiene and Tropical Medicine. To quantify the effect – and try to work out its cause – Logan and his colleagues infected some lab-grown Anopheles gambiae mosquitoes with Plasmodium parasites, while leaving others uninfected. They then tested how both groups were attracted to human smells. Mosquitoes are particularly attracted to foot odours, so Logan's team used nylon stockings containing the volatile chemicals produced by our feet. Over a period of three minutes, Plasmodium-infected mosquitoes landed and attempted to bite the stockings around 15 times on average. By contrast, the uninfected mosquitoes attempted to bite only around five times on average during that time. © Copyright Reed Business Information Ltd.

Keyword: Chemical Senses (Smell & Taste)
Link ID: 18160 - Posted: 05.16.2013

Zoe Cormier A study of two ancient hominins from South Africa suggests that changes in the shape and size of the middle ear occurred early in our evolution. Such alterations could have profoundly changed what our ancestors could hear — and perhaps how they could communicate. Palaeoanthropologist Rolf Quam of Binghamton University in New York state and his colleagues recovered and analysed a complete set of the three tiny middle-ear bones, or ossicles, from a 1.8-million-year-old specimen of Paranthropus robustus and an incomplete set of ossicles from Australopithecus africanus, which lived from about 3.3 million to around 2.1 million years ago. The ossicles are the smallest bones in the human body, and are rarely preserved intact in hominin fossils, Quam says. In both specimens, the team found that the malleus (the first in the chain of the three middle-ear bones) was human-like — smaller in proportion compared to the ones in our ape relatives. Its size would also imply a smaller eardrum. The similarity between the two species points to a “deep and ancient origin” of this feature, Quam says. “This could be like bipedalism: a defining characteristic of hominins.” It is hard to draw conclusions about hearing just from the shape of the middle-ear bones because the process involves so many different ear structures, as well as the brain itself. However, some studies have shown that the relative sizes of the middle-ear bones do affect what primates can hear2. Genomic comparisons with gorillas have indicated that changes in the genes that code for these structures might also demarcate humans from apes3. © 2013 Nature Publishing Group

Keyword: Hearing; Aggression
Link ID: 18151 - Posted: 05.14.2013

by Michael Balter Researchers debate when language first evolved, but one thing is sure: Language requires us not only to talk but also to listen. A team of scientists now reports recovering the earliest known complete set of the three tiny middle ear bones—the malleus ("hammer"), incus ("anvil"), and stapes ("stirrup")—in a 2.0-million-year-old skull of Paranthropus robustus, a distant human relative found in South Africa (see photo). Reporting online today in the Proceedings of the National Academy of Sciences, the researchers found that the malleus of P. robustus, as well one found earlier in the early human relative Australopithecus africanus, is similar to that of modern humans, whereas the two other ear bones most closely resemble existing African and Asian great apes. The team is not entirely sure what this precocious appearance of a human-like malleus means. But since the malleus is attached directly to the eardrum, the researchers suggest that it might be an early sign of the high human sensitivity to middle-range acoustic frequencies between 2 and 4 kilohertz—frequencies critical to spoken language, but which apes and other primates are much less sensitive to. © 2010 American Association for the Advancement of Science

Keyword: Hearing; Aggression
Link ID: 18150 - Posted: 05.14.2013

Ed Yong Many moths have evolved sensitive hearing that can pick up the ultrasonic probes of bats that want to eat them. But one species comes pre-adapted for anything that bats might bring to this evolutionary arms race. Even though its ears are extremely simple — a pair of eardrums on its flanks that each vibrate four receptor cells — it can sense frequencies up to 300 kilohertz, well beyond the range of any other animal and higher than any bat can squeak. “A lot of previous work has suggested that some bats have evolved calls that are out of the hearing range of the moths they are hunting. But this moth can hear the calls of any bat,” says James Windmill, an acoustical engineer at the University of Strathclyde, UK, who discovered the ability in the greater wax moth (Galleria mellonella). His study is published in Biology Letters1. Windmill's collaborator Hannah Moir, a bioacoustician now at the University of Leeds, UK, played sounds of varying frequencies to immobilized wax moths. As the insects “listened”, Moir used a laser to measure the vibrations of their eardrums, and electrodes to record the activity of their auditory nerves. The moths were most sensitive to frequencies of around 80 kilohertz, the average frequency of their courtship calls. But when exposed to 300 kilohertz, the highest level that the team tested, the insects' eardrums still vibrated and their neurons still fired. © 2013 Nature Publishing Group

Keyword: Hearing; Aggression
Link ID: 18137 - Posted: 05.09.2013

Researchers at the National Institutes of Health have uncovered firm evidence for what many mothers have long suspected: women’s brains appear to be hard-wired to respond to the cries of a hungry infant. Researchers asked men and women to let their minds wander, then played a recording of white noise interspersed with the sounds of an infant crying. Brain scans showed that, in the women, patterns of brain activity abruptly switched to an attentive mode when they heard the infant cries, whereas the men’s brains remained in the resting state. “Previous studies have shown that, on an emotional level, men and women respond differently to the sound of an infant crying,” said study co-author Marc H. Bornstein, Ph.D., head of the Child and Family Research Section of the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), the institute that conducted the study. “Our findings indicate that men and women show marked differences in terms of attention as well.” The earlier studies showed that women are more likely than men to feel sympathy when they hear an infant cry, and are more likely to want to care for the infant. Their findings appear in NeuroReport. Previous studies have shown differences in patterns of brain activity between when an individual’s attention is focused and when the mind wanders. The pattern of unfocused activity is referred to as default mode, Dr. Bornstein explained. When individuals focus on something in particular, their brains disengage from the default mode and activate other brain networks.

Keyword: Sexual Behavior; Aggression
Link ID: 18123 - Posted: 05.07.2013

By Scicurious In the great novel The Great Gatsby, Daisy, one of the love interests of the book, has a beautiful voice. She’s described otherwise, but you don’t really remember what she looked like, you remember how she sounded. Fitzgerald describes her voice as musical, running up and down and the scales when she talks. And you know what he’s talking about. You hear that voice in your head: light, breathy, utterly charming. You don’t really know what she looks like, but from imagining her voice, you know she is beautiful. What is it about this, or any voice, that makes it attractive? Is it the pitch? The tone? The firmness or breathiness of voice? And what is it about that voice, or any voice, that makes you know that someone is beautiful, handsome, masculine, feminine? The authors of this study wanted to see what makes a voice a VOICE. What acoustic factors make it most attractive to women and to men? To do this, they first took 10 young men, and had them rate the attractiveness of a female voice saying “good luck on your exams”. The voice actor said the phrase without any emotion using three different sound qualities: normal, breathy, and pressed (more of a hard tone). They then took the recording of this voice and modified it up and down, to create the phrase in several different pitches and formats. Specifically, they modified it upward toward what they hypothesized to mean “small body size and happiness” or downward toward what they hypothesized to mean “large body size and anger”. They showed that while increasing the pitch (higher) did not increase the attractiveness of the voice, lowering it decreased the attractiveness. And increasing the breathiness of the sentence increased attractiveness. The authors believe that this means that lowering the voice, and presumably indicating a larger body size (larger body size in general means the normal voice will be lower), reduced how attractive the men found the voice. © 2013 Scientific American

Keyword: Sexual Behavior; Aggression
Link ID: 18122 - Posted: 05.06.2013

By Jill U. Adams, Urban living may be harmful to your ears. That’s the takeaway from a study that found that more than eight in 10 New Yorkers were exposed to enough noise to damage their hearing. Perhaps more surprising was that so much of the city dwellers’ noise exposure was related not to noisy occupations but rather to voluntary activities such as listening to music. Which makes it hard for me not to worry that when my 16-year-old son is sitting nearby with his earbuds in, I can hear his music. There’s a pretty good chance that he’s got the volume up too loud — loud enough to potentially damage the sensory cells deep in his ear and eventually lead to permanent hearing loss. That’s according to Christopher Chang, an ear, nose and throat doctor at Fauquier ENT Consultants in Warrenton, who sees patients every day with hearing-related issues. “What he’s hearing is way too loud, because it’s concentrated directly into the ear itself,” he says of my son, adding that the anatomy of the ear magnifies sound as it travels through the ear canal. Listening to music through earbuds or headphones is just one way that many of us are routinely exposed to excessive noise. Mowing the lawn, going to a nightclub, riding the Metro, using a power drill, working in a factory, playing in a band and riding a motorcycle are activities that can lead to hearing problems. Aging is the primary cause of hearing loss; noise is second, says Brian Fligor, who directs the diagnostic audiology program at Boston Children’s Hospital, and it’s usually the culprit when the condition affects younger people. Approximately 15 percent of American adults between the ages of 20 and 69 have high-frequency hearing loss, probably the result of noise exposure, according to the National Institute on Deafness and Other Communication Disorders. © 1996-2013 The Washington Post

Keyword: Hearing
Link ID: 18038 - Posted: 04.15.2013

By Meghan Rosen Whether you’re rocking out to Britney Spears or soaking up Beethoven’s classics, you may be enjoying music because it stimulates a guessing game in your brain. This mental puzzling explains why humans like music, a new study suggests. By looking at activity in just one part of the brain, researchers could predict roughly how much volunteers dug a new song. When people hear a new tune they like, a clump of neurons deep within their brains bursts into excited activity, researchers report April 12 in Science. The blueberry-sized cluster of cells, called the nucleus accumbens, helps make predictions and sits smack-dab in the “reward center” of the brain — the part that floods with feel-good chemicals when people eat chocolate or have sex. The berry-sized bit acts with three other regions in the brain to judge new jams, MRI scans showed. One region looks for patterns, another compares new songs to sounds heard before, and the third checks for emotional ties. As our ears pick up the first strains of a new song, our brains hustle to make sense of the music and figure out what’s coming next, explains coauthor Valorie Salimpoor, who is now at the Baycrest Rotman Research Institute in Toronto. And when the brain’s predictions are right (or pleasantly surprising), people get a little jolt of pleasure. All four brain regions work overtime when people listen to new songs they like, report the researchers, including Robert Zatorre of the Montreal Neurological Institute at McGill University © Society for Science & the Public 2000 - 2013

Keyword: Hearing; Aggression
Link ID: 18030 - Posted: 04.13.2013

Published by scicurious I love salt. It's just delicious. I wrote this post while noshing on deliciously salty popcorn, after a dinner which I put salt on. I crave salt so much that my parents used to joke about getting me a salt lick. And I'm not alone. Sodium is an incredibly important part of life, which means it's also an important part of what we eat. To make sure we get enough salt, animals have evolved salt-sensing systems, and low levels (below 100 mM of NaCl) of salt are very attractive. But there IS such a thing as too much salt. High levels of salt (>300 mM NaCl) are really aversive (from personal experience, I wonder if Carrabba's restaurant has concentrations of salt in their food over 300 mM). Most animals will quickly turn up their noses at a high salt concentration. You probably know that you have classes of receptors on your tongue for taste (though they are not clustered into areas of your mouth, like front for sweetness, as previously thought). You have sweet, umami (savory), bitter, sour, and salt. In most animals, sweet and umami are always attractive, while bitter and sour are nasty (except where we have overcome the aversion to enjoy things like coffee and beer). Salt, though, is the only one that goes two ways, with low levels being attractive and high levels being aversive. Now we know how low salt works. The salt receptors that are currently known are good for detecting low salt. But high salt, that's more difficult. First of all, our aversion to high salt concentrations is not very selective. While low salt detection is limited to good old NaCl, high salt detection is non-specific, working for many salts including NaCl, but others as well (like KCl). Neurotic Physiology Copyright © 2013

Keyword: Chemical Senses (Smell & Taste)
Link ID: 18025 - Posted: 04.13.2013

Published by scicurious Today's post comes to you courtesy of Mary Roach (aka, the person I want to be when I grow up). I have a copy of her latest book, Gulp: adventures in the alimentary canal that I am reading for review, and a weird science connoisseur such as myself of course spends half her time in the bibliography section, wherein I located this paper. This paper may thus be taken as a pre-review of the book. Spoiler: so far, the book is FABULOUS, but should never be read while eating. Ah, goat milk. When I think of goat milk, I think of places like farmer's markets, Whole Foods, and little Heidi dancing through the alps. I'll admit to never having drunk raw goat milk (though I do LOVE goat cheese). But after having read this paper, I'm afraid that I do not WANT to try raw goat milk. Why? I'm afraid of the taste...the goaty taste...that is potentially hot, sexy goaty hormones. Hot sexy goat hormones sprayed around in hot, sexy goaty URINE. So, goat milk doesn't usually taste...well, goaty. Usually it tastes pretty much like cow milk (whole fat cow milk, that is). But sometimes, you'll get a bad batch. Nothing's WRONG with it, per se, it's still healthy and not bad, but it's...goaty. The flavor and smell are musky and weird, and not at all tasty. So obviously you want to find the source of that problem. For years, people who raise goats have pinpointed the MALE goat as the source of the issue. Male goats smell very goaty indeed, particularly during the goat mating season (the rutting season). Some of the odors they emit are so strong they can be smelled several hundred meters away. The odors are very volatile, so they will spread easily, and the idea has long been that if your male goat is around the ladies, his manly odors will get on them and in them, and thus in their milk, resulting in goaty milk (which, if the male goat is the cause, means that goaty milk is really just...MANLY). So goat farmers usually keep their male goats at a good distance from the females during the rutting season, to keep the males from getting their...manliness in the milk. Manliness is just not very tasty. Copyright © 2013

Keyword: Chemical Senses (Smell & Taste); Aggression
Link ID: 17969 - Posted: 03.30.2013

by Hal Hodson THAT fried chicken advert is about to get even more tempting. Soon it might be pumping out the mouth-watering smell of the stuff too. Tough luck if you're a veggie. The "smelling screen", invented by Haruka Matsukura at Tokyo University of Agriculture and Technology in Japan and colleagues, makes smells appear to come from the exact spot on any LCD screen that is displaying the image of a cup of coffee, for example. It works by continuously feeding odours from vaporising gel pellets into four air streams, one in each corner of the screen. These air streams are blown out parallel to the screen's surface by fans, and varying the strength and direction of them manoeuvres the scent to any given spot on the screen. The airflow is gentle enough that the team have been able to create the illusion that the smell is actually wafting from a digital object on-screen. The current system only pumps out one scent at a time, but Matsukura says the next stage is to incorporate a cartridge, like those for printers, which allows smells to be changed easily. The screen was shown at the IEEE Virtual Reality conference in Orlando, Florida, last week. Matsukura suggests it could also be used to enhance advertising screensMovie Camera and museum exhibits. © Copyright Reed Business Information Ltd.

Keyword: Chemical Senses (Smell & Taste); Aggression
Link ID: 17967 - Posted: 03.30.2013

By Andrew Grant A simple plastic shell has cloaked a three-dimensional object from sound waves for the first time. With some improvements, a similar cloak could eventually be used to reduce noise pollution and to allow ships and submarines to evade enemy detection. The experiments appear March 20 in Physical Review Letters. “This paper implements a simplified version of invisibility using well-designed but relatively simple materials,” says Steven Cummer, an electrical engineer at Duke University, who was not involved in the study. Cummer proposed the concept of a sound cloak in 2007. Scientists’ recent efforts to render objects invisible to the eye are based on the fact that our perception of the world depends on the scattering of waves. We can see objects because waves of light strike them and scatter. Similarly, the Navy can detect faraway submarines because they scatter sound waves (sonar) that hit them. So for the last several years scientists have been developing cloaks that prevent scattering by steering light or sound waves around an object. The drawback of this approach, however, is that it requires complex synthetic materials that are difficult to produce. © Society for Science & the Public 2000 - 2013

Keyword: Hearing
Link ID: 17966 - Posted: 03.30.2013