Waves X-noise Torrent ##BEST##

Several types of mammals are susceptible to noise-induced hearing loss. Human beings may be impacted by road traffic noise (e.g., city, industrial, and airport noise), by construction noise (e.g., rock quarrying, drilling, and blasting), and by recreational noise (e.g., hunting, boat noise, and recreational aviation). Noise-induced hearing loss can be permanent and irreversible. It is a risk for all age groups, particularly for children and young adults who live and work in noisy environments. Learning more about noise-induced hearing loss can help in reducing its negative effects. Detecting early changes in the auditory system, before it is too late, can be difficult. Many changes to the auditory system occur at a cellular and molecular level with no obvious change in the auditory system acuity and sensitivity. A change in the auditory system acuity can be followed by a change in the psychological function known as auditory discomfort, which often occurs when the effect of a noise exposure exceeds the individual's capacity to cope. This response can be behavioral (e.g., a reduction of performance, such as decreased accuracy on a psychometric test), physiological (e.g., tremor, muscle tension), or psychophysiological (e.g., an increase of temperature, heart rate, blood pressure).

Ten years ago, little was known about the direct effects of noise on the nervous system. This knowledge has been changing. Research from around the world has shown that noise can change the function and structure of the brain. Noise damages the brain in several ways, in ways that vary depending on the length of noise exposure and the age of the exposed individual (Karmonik and Azemi 2011; Shao et al. 2016; Karmonik et al. 2015). The hippocampus, a part of the limbic system of the brain, is especially vulnerable to noise exposure. Noise exposure can damage the hippocampus in ways that lead to emotional and cognitive changes. Noise-induced hearing loss can affect the hippocampus and the limbic system. It can also damage the amygdala, a small almond-shaped structure thought to be the center of emotion, fear, and other emotional responses in the brain. Damage to the amygdala can result in a loss of spontaneous behavioral responses, such as moving out of the way of a dangerous animal. For example, repeated exposure to loud noise can trigger impaired attention to danger or impaired perception of threat in humans (Karmonik et al. 2015).

Damage to IHCs can be caused by acoustic overexposure, commonly in the form of loud noise. A sound exposure can cause damage to IHCs when the energy of the sound exceeds the capacity of the cochlea to protect itself, resulting in cochlear dysfunction (Day et al. 2016b). A sound exposure can cause damage if the frequency of the sound is outside the range of frequencies that the cochlea and cochlear blood vessels are tuned to (Day et al. 2016b).

In the sea, ship noise is an acoustic wave emitted or reflected from the ship hull, which travels along the water-air interface and reaches or is reflected from the seafloor. The main sources of noise are propellers, propeller cavitations, and hull resonance. The safety of marine vessels has been a major problem for humans, and there has been a growing interest in ship noise over the last two decades. 827ec27edc