Noisy environments make young songbirds shuffle their tunes

A baby songbird prefers to learn the clearest versions of songs he hears and uses them to build his personal playlist for life. As a result, noise, from nature and humans, influences which songs a bird learns to sing and can create lasting changes to his species' top tunes, the study's results suggest. 

"There's been an enormous amount of interest in how anthropogenic factors affect the channels animals use for communication and in particular how human noise affects birdsong," said Duke University biologist and study co-author Steve Nowicki. "As far as we know, this is the first study that can link noise to cultural evolution of bird song." 

The team designed the study to test a 30-year-old hypothesis suggesting that young birds memorize and later sing the clearest songs they hear during their critical learning period. In the experiment, Nowicki and his collaborators collected nine male, swamp-sparrow nestlings and hand-raised them in a soundproof room. Twice a day for 12 weeks, the birds heard recordings of 16 song types sung by adult males of their species. Eight song types were degraded, or noisy, by being broadcast across a typical sparrow territory of 25 meters and then re-recorded. The other eight were clean copies of similar-sounding, but different songs. When the birds later matured and began to sing, they only repeated the clear songs. 

"It wasn't too surprising that the sparrows preferred them," said Duke behavioral ecologist Susan Peters, lead author of the study. "What is exciting is how clear-cut the results are. All of the birds learned clear songs and none learned any of the degraded songs," she said. The results appeared online June 20 in the journal Biology Letters. This "simple" but "elegant" experiment "says a great deal about how birds put to use their extraordinary ability to hear small-time differences," said Eugene Morton, a biologist at York University in Canada who was not involved in the study. The birds use this ability to learn songs that transmit through their habitat with the least amount of degradation. "In this way, the birds themselves reject songs less well suited to their environment," an example of cultural selection, Morton said. 

Scientists consider the song shifts to be selected culturally, rather than naturally, because the songs are learned, not innate. "This is important because cultural selection can happen more rapidly than natural selection," Peters said. "It helps to explain why birdsong is so diverse," and shows evidence that song variation depends on the bird's habitat. She added that noise from cities and humans would have the same effect on song selection. "We already knew that some birds can adjust some features of their song when confronted with anthropogenic noise, and now we know that this may have an impact on cultural transmission of their song," she said. If naturally noisy songs are less desirable to learn, then songs shaped by human noise are probably less likely to be passed down and learned generation after generation. "Who would have thought that a swamp sparrow song might be affected by human activity?" Peters said. 

Source: Phys.Org

Noise-absorbing windows

The noise of aircraft taking off, road traffic or a booming discotheque often drive inhabitants of the neighborhood to a nervous frenzy. The first-ever windows with active sound insulation offer much-needed relief to local residents in their homes and offices.

When an aircraft takes off over your roof every five minutes, the noise makes it impossible to hold a conversation. Windows can’t provide adequate protection against this type of noise pollution.

A double or triple layer of glass will absorb the high frequencies, but can do nothing against low-frequency noise such as that produced by aircrafts or thrumming bass tones of disco music. This would normally call for panes of glass so thick and heavy that their use would be almost prohibitive in lightweight constructions or extensive curtain-wall facades.

Researchers at the Fraunhofer Institute for Structural Durability and System Reliability LBF and Darmstadt University of Technology have found a solution, namely a new type of soundproof window. “Tests have shown that our windows are capable of lowering noise levels by an average of six decibels at frequencies between 50 and 1000 hertz. The perceived noise indoors is only half as loud,” says Dr. Thilo Bein, who manages the institute’s department of energy, environment and health. “We have even been able to reduce the volume of certain test signals by up to 15 decibels.” The experts have predicted a reduction of up to 10 dB for the engine noise of passenger aircraft in the frequency range below 1000 Hz.

When noise waves meet the walls of a building, they can be propagated to the interior by various routes. One is by causing the windows to vibrate, thus carrying the noise into the building. The other is by transmitting sound waves to the interior via the bridges in the structure where the curtain-wall elements are attached to the frame of the building. In both cases, the researchers have found a way to prevent the propagation of sound energy. Acceleration sensors attached to the window panes measure the vibrations generated by the noise.

A thin chip of piezoelectric material also attached to the window counteracts the vibration by generating an oscillation at the same pitch but in the opposite sense to that measured by the sensor – causing the pane to move in the opposing direction. “We have devised a similar solution for the points where the outer cladding is attached to the frame of the building. In this case, a stack of piezoelectric chips, rather than a single piezoelectric strip, counteracts the impinging force,” says Bein.

Source: Phys.Org 

How to fall asleep when there is loud noise outside

If you are sensitive to slightest of noise then it is possible that you remain sleep deprived for several days in the wake of surrounding noises. Benefits of having a good night’s sleep are quite well known and it is established that a good sleep helps in developing healthy body and mind. There are many events that could disturb your sleep and most probably you won’t get it afterwards. It could be loud noise of television set, bad weather, loud music or gregarious snoring. Even if you feel it is impossible to sleep with so many noises, there are some ways by which you could achieve it.

• The first obvious option to shut down the outside sound is to close the windows. If your window is not properly caulked then it may fail to seal the outside noise hence in this case, seal the window gaps with paper cutouts. If the climate is hot and unbearable then just switch on your air conditioning system. This will also help in eliminating the outside noise as most of the air conditioning units create some or other kind of noise which would distract your attention from the outside noise.

• Hot water is best for getting good night’s sleep and if you are not in favor of bathing at night then just wash your legs and palms with hot water, you are surely going to get sound sleep. Even drinking warm milk at bedtime helps to obtain good sleep despite of outside music.

• Another way of getting sleep in heavy sound is to block the sound with other sound. This works best and if you have iPod or music player just put the soft music over the system and try to ignore the outside voice. It works effectively if you put the music over headphones while keeping the volume on lower side to help the brain relaxation.

• Lie down on the bed and by imagining each portion of your body, call out to relax. Start with your toe nails and work upwards but remember to engage every part separately. For example start as ‘my first finger of left toe is relaxing then second’ and so on up till head and hair strands. This movement engages your mind in different direction and slowly you will notice that you are getting sleepy.

• There is another way to get sound sleep in heavy noise and that is to construct and imagine happy event. This may seem foolish but it works for many people. What you have to do is to imagine a person with whom you want to spend quality time, and then imagine a dream destination putting elements that you fantasize. Next is to indulge yourself in possible conversations with the person and also imagine his/her replies. You can make it in the form of dream date, happy meeting or anything you like.

• If the sound is too loud then best way to get sleep in this condition is to count numbers starting from last to first. Imagine a number that should be of three digits and from that start counting backwards. This helps a lot to get sleep, as your brain is involved in counting activity, you will forget everything about the outside voice. If possible, count numbers in your mother tongue as it makes the procedure simple and effective.

• Record and listen a sound that sooths your mind, most people record relaxing sound of waves, air, gushing water or similar and listen with the help of recorder in night. This should be listened with the help of headphones to get maximum effect. The choice of sound is totally yours and if you are spiritual then you can record poems, chanting of OM and similar god related texts.

• The next tip may sound weird but helps many to get rid of the annoying sound. If you have ceiling fan at home then stare at the fan and its circular movements as this sometimes make the brain dizzy which could be concluded in sound sleep. If you don’t have ceiling fan then stare at any object present in your room that is moving which could be your wall clock.

• If nothing helps in getting sleep then you may consider purchasing earplugs that seal the outside sound and provide healthy sleep. Having earplugs for sealing sound could be effective but it produces risk of sleeping until late because you won’t even hear the alarm clock. It is better that you try all the above mentioned tips as they would surely give you sound sleep in heavy outside noise.

Via How to go sleep 

Kill Noise Earplugs: now you can easily talk while filtering ambient noises

Noise cancellation earphones eliminate ambient noises so that you can listen to music clearly or sleep peacefully in the drone. 

But how about the time that you want to filter background noises and, at the same time, hold a conversation? 

The Kill Noise earplug suits this purpose and realizes noise reduction by electronic filtering, which can make people communicate easily in the noisy environments. The bright-orange polyester buds have an adjustment knob to set the filters and a built-in battery that lasts long.

Info at Yanko Design

72% of Teenagers Experienced Reduced Hearing Ability After Attending Concert

M. Jennifer Derebery, MD, House Clinic physician, along with the House Research Institute tested teens’ hearing before and after a concert.

The hearing loss that may be experienced after a pop rock concert is not generally believed to be permanent. It is called a temporary threshold shift and usually disappears within 16-48 hours, after which a person’s hearing returns to previous levels. “Teenagers need to understand a single exposure to loud noise either from a concert or personal listening device can lead to hearing loss,” said M. Jennifer Derebery, MD, lead author and physician at the House Clinic. “With multiple exposures to noise over 85 decibels, the tiny hair cells may stop functioning and the hearing loss may be permanent.”

In the study, twenty-nine teenagers were given free tickets to a rock concert. To ensure a similar level of noise exposure for the teens, there were two blocks of seats within close range of each other. The seats were located in front of the stage at the far end of the venue approximately 15-18 rows up from the floor. The importance of using hearing protection was explained to the teenagers. Researchers then offered hearing protection to the subjects and encouraged them to use the foam ear plugs. However, only three teenagers chose to do so. Three adult researchers sat with the teenagers. Using a calibrated sound pressure meter, 1,645 measurements of sound decibel (dBA) levels were recorded during the 26 songs played during the three hour concert. The sound levels ranged from 82-110 dBA, with an average of 98.5 dBA. The mean level was greater than 100 dBA for 10 of the 26 songs.

Following the concert, the majority of the study participants also were found to have a significant reduction in the Distortion Product Otoacoustic Emissions (OAE) test. This test checks the function of the tiny outer hair cells in the inner ear that are believed to be the most vulnerable to damage from prolonged noise exposure, and are crucial to normal hearing, the ability to hear soft (or low level sounds), and the ability to understand speech, especially in noisy environments. With exposure to loud noise, the outer hair cells show a reduction in their ability to function, which may later recover. However, it is known that with repeated exposure to loud noise, the tiny hair cells may become permanently damaged. Recent animal research suggests that a single exposure to loud noise may result in permanent damage to the hearing nerve connections themselves that are necessary to hear sound.

Following the concert, 53.6 percent of the teens said they did not think they were hearing as well after the concert. Twenty-five percent reported they were experiencing tinnitus or ringing in their ears, which they did not have before the concert.

In the most recent government survey on health in the United States National Health and Nutrition Examination Survey (NHANES) 2005-2006, 20% of adolescents were found to have at least slight hearing loss, a 31% increase from a similar survey done from 1988-1994.

“It also means we definitely need to be doing more to ensure the sound levels at concerts are not so loud as to cause hearing loss and neurological damage in teenagers, as well as adults,” said Derebery. “Only 3 of our 29 teens chose to use ear protection, even when it was given to them and they were encouraged to do so. We have to assume this is typical behavior for most teen listeners, so we have the responsibility to get the sound levels down to safer levels.”

Researchers recommend teenagers and young adults take an active role in protecting their hearing by utilizing a variety of sound meter ‘apps’ available for smart phones. The sound meters will give a rough estimate of the noise level allowing someone to take the necessary steps to protect their hearing such as wearing ear plugs at a concert. In addition, Derebery and the study co-authors would like to see concert promoters and the musicians themselves take steps to lower sound levels as well as encourage young concert goers to use hearing protection.

Info accessed at Science Daily

MARVEL designed a superhero to help a 4-year-old with hearing loss

A 4-year-old boy in Salem who decided he did not want to wear his blue hearing aid to school anymore received some new inspiration after Marvel Comics designed a superhero after him.

Christina D’Allesandro said her son Anthony Smith cannot hear out of his right ear and has hearing loss in his left ear. She said Anthony woke up one day and decided that he did not want to wear his blue hearing aid.

“Basically, one day he woke up and I said, ‘OK, time to put in your hearing aid,’ and said, ‘Let’s put in blue ear.’ We’ve always called it that. And he said, ‘No, superheroes don’t wear blue ears,’” D’Allesandro said.

D’Allesandro assured her son that superheroes did wear hearing aids. She said she wanted to make sure, so she emailed the experts at Marvel Comics in New York City. Marvel sent back a comic book cover featuring Hawkeye, a superhero who lost his hearing. D’Allesandro said her son was captivated by the image. Marvel then sent a drawing of a new superhero inspired by Anthony: Blue Ear. Another sketch arrived portraying Hawkeye and Blue Ear together.

Anthony’s grandfather, N.H. Sen. Lou D’Allesandro, said he was happy to hear of Marvel’s help.

“This is a feel-good moment. This is a feel-good story, and we’ve got to get the world to recognize that,” he said.

Christina D’Allesandro said Anthony, like Blue Ear, is proud to wear his hearing aid and share his good news with others at his school for children with hearing loss. The school had a superhero week, and a costume has been ordered for Anthony. D’Allesandro said she hopes to finally meet and thank the heroes at Marvel Comics someday.

Info accessed at Hearing Aid Center

New Stem Cell Therapies Being Developed for Hearing Loss

Vitro Diagnostics Inc has announced that it is developing stem cell products that could one day lead to therapies to prevent, reverse, and restore hearing, according to the company, in animals and humans. Vitro's therapeutic products include molecular compositions to promote, maintain, and restore inner ear hair cells and related structures together with adult stem cell transplantation to restore hearing loss. 

Vitro's intellectual property has application to hearing restoration and prevention of hearing loss through a series of products envisioned to provide various treatment options for hearing loss. These discoveries may lead to new pharmaceutical agents that stimulate activation of native adult stem cells to regenerate inner ear hair cells, together with other cells derived from adult stem cells, without the necessity of stem cell transplantation. 

Recombinant cytokines, including erythropoietin and granulocyte colony stimulating factor, are now widely used for therapeutic activation of the hematopoietic stem cell system for treatment of adverse effects of chemotherapy and represent major products of the biotechnology industry.

Vitro has developed other proprietary technology related to stem cell products and technology that has a broad application to various areas in medical research and therapy. Modern stem cell technology is rapidly evolving and holds promise to revolutionize medicine by allowing replacement of any type of cell within the human body. Diseases characterized by cellular degeneration, such as hearing loss, may soon be treatable through development and further commercialization.

While the research and use of human embryonic stem cells is politically and ethically controversial, Vitro's stem cell technology is based on adult human stem cells that are derived without sacrifice of the embryos needed to generate embryonic stem cells. Transplantation of adult stem cells, derived from various tissues, such as bone marrow, has been used for the past 50 years to treat leukemia, lymphoma, and other blood disorders. The same techniques can now be applied for hearing loss therapies.

The company says that is now seeking partnerships to commercialize its stem cell products related to treatment of hearing loss.

Info accessed at Hearing Review