Audição e ecolocalização

Os animais ouvem bem?
Respondemos instintivamente a esta questão: "Claro!" ou "muito melhor do que os seres humanos". Em alguns casos, isto é verdade. Com as suas orelhas longas, um feneco pode ouvir insetos que se move debaixo do solo. Uma capacidade prática para este animal, cuja visão é consideravelmente subdesenvolvida. Já os lobos são mestres na arte de localizar as suas presas seguindo o ruído que estas produzem.  Quem tem um cão sabe que este vai saltar com a chegada de uma pessoa familiar, muito antes de que ela toque a campainha. Alguns cães são mesmo capazes de reconhecer o som do motor do carro do seu dono.

Mas a capacidade de ouvir não é igual entre as diferentes espécies do reino animal. As aranhas e cobras passam a vida inteira num silêncio quase total. Percebem os sons de uma maneira diferente: o corpo da cobra capta as vibrações sonoras através do solo e a aranha sabe que algo acontece quando as vibrações atingem os pêlos das suas patas. Alguns mamíferos, como os morcegos e os golfinhos usam a ecolocalização para se orientar. Trata-se de uma capacidade para deteta a posição e/ou distância de objetos ou animais através da emissão de ondas ultrassónicas e análise do tempo gasto no regresso à fonte sobre a forma de eco.

Há pelo menos um homem que foi capaz de dominar esta técnica. O norte-americano Daniel Kish perdeu a visão na infância como resultado de um cancro. Ele aprendeu a orientar-se no espaço através da emissão de sons e interpretação do seu eco. E mesmo que já tenha perdido alguns dentes e esfolado joelhos, ele gosta de andar de bicicleta. Kish fundou uma organização chamada World Access for the Blind, que visa, entre outros, para ensinar um máximo de cegos a "ver" com os ouvidos.

How To Reduce Noise Pollution and Its Negative Effects

Noise pollution can negatively impact the body in significant ways, including elevated blood pressure, impaired cognitive functioning, and other effects of chronic stress. The following are effective strategies you can use to limit the negative impact of noise pollution and safeguard your health and happiness.

Limit The Noise

Your first line of defense against noise pollution is to do what you can to control your environment, and limit the noise that enters your space. The following are ways that you can limit environmental noise and blunt the effects of noise pollution: 

• Double-Paned Windows and Weather Stripping: If you live in a noisy city or near an airport, you can reduce noise in your home considerably by installing dual-paned windows, weather stripping, and even added insulation. As a bonus, these changes can also reduce your heating and cooling bills, and help the environment! 
• Reduce Workplace Noise: If you work in a noisy office, you may want to talk to your employer about taking steps to reduce office noise, which has been found to affect the health and productivity of workers. 
• Turn Off The T.V.: When you’re at home, a constant backdrop of television can have an effect on you as a distraction and potential stressor. 
• Make Bigger Changes: You may even consider moving or changing jobs if you experience significant levels of noise that you can’t reduce in other ways. It sounds like a drastic step, but considering the toll that a noisy environment can take on your health, it may be an option to consider. 

Info at Stress.About.Com

Mais de 40% da população portuguesa tem problemas de concentração devido ao ruído

Para assinalar o Dia Internacional da Consciencialização para o Ruído, a GAES-Centros Auditivos acaba de divulgar um estudo onde mostra como o ruído afecta o dia-a-dia das pessoas. Em Portugal, mais de 40% da população sofre de problemas de concentração associados ao ruído.

A perda auditiva é um problema de saúde que afecta já cerca de 1 milhão de portugueses e, a nível mundial, cerca de 120 milhões de pessoas têm já a sua audição afectada devido ao ruído.

O ruído em excesso - ou poluição sonora - é um grave problema que afecta toda a população, em especial a que vive nas grandes cidades. Todos os dias, são várias as actividades que expõem os cidadãos a níveis de poluição sonora altamente prejudiciais para a saúde. Sem se darem conta, estão expostos a situações em que o ruído ambiente é constante e com um elevado impacto nocivo para o seu bem-estar.

Cerca de 60% da população portuguesa vive com níveis de ruído acima do recomendado, que é de 55 decibéis, e cerca de 20% está exposta a barulho incomodativo (mais de 65 decibéis) de forma constante, o que se manifesta num forte impacto para a sua saúde, em especial de possíveis problemas auditivos.

Dulce Martins Paiva, directora-geral da GAES – Centros Auditivos Portugal, afirma: «Na GAES-Centros Auditivos temos a preocupação de alertar os nossos pacientes para o ruído que os rodeia, e que pode prejudicar a sua audição. Desenvolvemos este estudo em cinco países, onde estamos presentes – Portugal, Espanha, Venezuela, Equador e Chile – e os resultados foram muito semelhantes. As pessoas precisam de estar alertas para os níveis de ruído no seu dia-a-dia, e na GAES podemos ajudá-lo a combater possíveis problemas auditivos devido ao ruído.»

No dia 30 de Abril, a GAES-Centros Auditivos vai alertar a população para o excesso de ruído nas grandes cidades, e irá marcar presença em Coimbra com uma acção de rua na Avenida Central às 18:00.

Notícia de Diário Digital

If You Can't Eliminate The Noise Pollution... Reduce it!

If you can’t eliminate noise from your environment, you can actually create a healthier environment by replacing stress-inducing environmental sounds with more pleasing ones. For example, you can reduce the impact of airport or city noise with a white noise machine or 'sound spa'. They play sounds ranging from waterfalls to rain to babbling brooks to basic static, and these sounds mask the more jarring environmental noises that can distract you or negatively affect your sleep. They can also make it easier to meditate or practice visualization techniques.

Additionally, you can drown out distracting sounds from a noisy office environment or neighborhood with music from your iPod or stereo and enjoy the stress management and health benefits of music while lessening the impact of the other noise. This can also improve your mood, boost your immunity, calm your physiology, or energize you. While you’re really trading some sounds for others, the sounds of nature or music can be more soothing and better for your health.

Info from: Stress.about.com

Stress and Noise Pollution: How You May Be At Risk

What Is Noise Pollution?

Noise pollution can be defined as intrusive noise that disrupts, distracts, or detracts from regular functioning. And while people mainly think of noise pollution as a problem of the big cities, with the competing sounds of more people in a smaller space, noise pollution can also be found in suburban neighborhoods (in the form of leaf blowers, lawn mowers, and home construction) and even individual homes and offices at levels that can have a negative impact on your health and productivity.

Causes of Noise Pollution 

While there are many different sources of noise pollution, there are some main culprits that have been researched and found to have a negative impact on health. They include the following:

Airplanes—It’s been well-documented that noise pollution from airplanes has a significant negative impact on the health and wellbeing of those who live close to airports. This can include heart disease, high blood pressure and chronic stress. (About.com’s Environment Guide has more information on the effects of airports and noise pollution.)

Cars--One of the complaints of those who live in big cities or on busy streets is the disruption from the sounds of traffic. Interestingly, though, even low levels of traffic noise can be damaging to people, and traffic noise is one of the most commonly experienced contributors to noise pollution.

Workplace Noise—Most of us may think of loud assembly lines or construction sites when we think of noise pollution in the workplace, and while these examples definitely apply, regular offices are not immune. With more people packed into busy office spaces, office noise is a common complaint. Co-workers who talk, drum their fingers on the desk, or offer other distracting noises can decrease the productivity of those around them without realizing it.

Home Sound--Many people don’t think of their homes as ‘noisy’, but if there’s a lot of activity in the home, including a constantly running t.v., this overall noise level can actually be a threat to concentration and a cause of stress. In fact, children from more noisy homes do suffer ill effects from this type of sound pollution that include less cognitive growth, delayed language skills, increased anxiety, and impaired resilience, according to a Purdue University professor in a related press release.

Info at Stress.About.Com

Gare aux effets des baladeurs MP3 sur l'audition

Les baladeurs MP3 d'aujourd'hui ont envoyé le Walkman au rayon des antiquités: il est maintenant possible d'écouter de la musique de bonne qualité pendant des heures et à des volumes de son élevés. Souvent trop élevés. 

Et les spécialistes sont de plus en plus inquiets des conséquences néfastes pour l'audition des adolescents avec l'apparition de plus en plus précoce de baisse sensible de l'audition, que certains appellent même une «épidémie de troubles auditifs».

Un adolescent sur quatre est à risque d'une perte d'audition résultant directement de ses habitudes d'écoute avec son baladeur, affirme ainsi le Pr Chava Muchnik, de la Tel Aviv University au terme de son étude, publiée dans l'International Journal of Audiology. 

Près de 289 adolescents, entre 13 et 17 ans, ont participé à l'étude. Ils ont été interrogés sur leurs habitudes d'écoute avec leur iPod ou autre baladeur MP3. Et en particulier sur le niveau sonore et la durée d'utilisation. Dans un deuxième temps, le volume du son des baladeurs a été mesuré chez 74 adolescents dans un environnement calme puis dans un environnement bruyant. Les volumes mesurés ont servi à établir les risques potentiels pour l'audition des adolescents.

Près de 80 % des adolescents participants à l'étude utilisaient leur baladeur très régulièrement, 21 % d'entre eux l'écoutant de 1 à 4 heures, et 8 % s'en servant plus de 4 heures consécutivement.

«Dans 10 ou 20 ans, estime le Pr Muchnik, il sera trop tard et on verra que toute une jeune génération souffre de surdités partielles beaucoup plus tôt qu'attendu en fonction du vieillissement». Elle recommande ainsi que tous les pays adoptent, pour commencer, les normes européennes qui limitent à 100 décibels le volume maximal des iPod et des baladeurs MP3, dont certains, non «bridés», peuvent atteindre près de 130 décibels. Mais 100 dB, cela équivaut déjà au niveau acoustique d'une boîte de nuit. Et l'on sait qu'un risque pour l'oreille est déjà avéré à partir de 80 dB. Les spécialistes recommandent que des campagnes de prévention soient menées pour sensibiliser les enfants et les parents aux dangers de ces décibels.

Info sur Le Figaro SANTÉ

Sono, a noise cancelation and isolation device that sticks on your window

If you’re the sort that needs peace and quiet to get anything done, escaping the noise pollution of every day life — regardless of where you’re located — is no easy task. A new device that sticks onto your window, Sono, will not only cancel real-world noise, but isolate the noises you’d prefer to hear, if any.

You live in a corner apartment, and your one, meager window faces a beautiful, serene park. However, in front of that park is a major metropolitan road, host to loud traffic throughout the day. If not for the constant stream of cars and barking dogs, the soothing sounds of chirping birds and the wind rustling through trees would make its way across the street and into your bedroom. With Sono, you can stick the device right on your window, and fiddle with some settings to either cancel out noise entirely, or cancel out the specific noises that are drowning out the peaceful ones.

Sono it’s a concept created by Austrian industrial designer Rudolf Stefanich. Sono works by vibrating a window in a pattern counter to the vibrations caused by the ambient noise, essentially turning the surface into a noise-canceling speaker. During prototype testing, Sono’s transducer used active noise canceling to successfully lower the audio signal by 12 decibels — which would probably do a good job of blocking out quieter sounds in the 30-80 dB range, but you’d still definitely hear traffic and other loud sounds.

The device employs concentric broadband antenna rings, and can be charged through WiFi signals or the standard electric outlet, so your noise shield won’t unceremoniously lower in the middle of the night.

The strength of Sono is not that it can cancel out obnoxious ambient noises, but can still filter pleasant ambient noises through. So, not only can you still get the chirping birds and rustling leaves from that park across the street, but the sounds are natural — not some recreation on your phone that sounds very digital. Though Stefanich’s device is more of a concept than a tangible item, the theory behind the device was successfully tested with that aforementioned prototype, and it is a finalist for the James Dyson Award.

Info from Extreme Tech