News tagged with noise

Lagos tries to tackle noise pollution

Nigeria's chaotic megacity Lagos on Wednesday sought to impose a one-day ban on the use of the car horn, hoping to raise awareness about damaging noise pollution and improve quality of life.

Oct 15, 2014
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Sounds of summer may threaten your hearing

(HealthDay)—Some of the most common sounds of summer—such as outdoor concerts, fireworks and construction—can pose a threat to your hearing if you don't take steps to protect yourself, an expert warns.

Jun 27, 2014
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Does 'free will' stem from brain noise?

Our ability to make choices—and sometimes mistakes—might arise from random fluctuations in the brain's background electrical noise, according to a recent study from the Center for Mind and Brain at the ...

Jun 09, 2014
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U-M researchers: Turn down the volume

As the nation continues to focus on health care prevention through reform, one cause of serious illness and even death gets ignored—environmental noise pollution.

Dec 06, 2013
popularity 4.7 / 5 (3) | comments 0

Noise

In common use, the word noise means any unwanted sound. In both analog and digital electronics, noise is random unwanted perturbation to a wanted signal; it is called noise as a generalisation of the acoustic noise ("static") heard when listening to a weak radio transmission with significant electrical noise. Signal noise is heard as acoustic noise if the signal is converted into sound (e.g., played through a loudspeaker); it manifests as "snow" on a television or video image. High noise levels can block, distort, change or interfere with the meaning of a message in human, animal and electronic communication.

In signal processing or computing it can be considered random unwanted data without meaning; that is, data that is not being used to transmit a signal, but is simply produced as an unwanted by-product of other activities. "Signal-to-noise ratio" is sometimes used to refer to the ratio of useful to irrelevant information in an exchange.

In biology, noise can describe the variability of a measurement around the mean, for example transcriptional noise describes the variability in gene activity between cells in a population.

In many cases, the special case of thermal noise arises, which sets a fundamental lower limit to what can be measured or signaled and is related to basic physical processes described by thermodynamics, some of which are expressible by simple formulae.

In some fields, noise means unwanted information or data that is not relevant to the hypothesis or theory being investigated or tested.

This text uses material from Wikipedia licensed under CC BY-SA