buku komposisi gorys keraf pdf 191
buku komposisi gorys keraf pdf 191
Buku Komponis Keraf PDF
buku komposisi gorys keraf pdf 191
buku komposisi gorys keraf pdf 191
buku komposisi gorys keraf pdf 191
buku komposisi gorys keraf pdf 191
buku komposisi gorys keraf pdf 191
buku komposisi gorys keraf pdf 191
buku komposisi gorys keraf pdf 191
buku komposisi gorys keraf pdf 191
Low frequency acoustic trauma in free-living killer whales (Orcinus orca).
The purpose of this study was to evaluate whether cumulative exposure to low frequency noise had affected the hearing of free-living killer whales (Orcinus orca) at low sound levels. Six juvenile killer whales from the wild were trained to respond to low frequency acoustic signals. Each animal was exposed to 1 s long random signals with a frequency between 0.5 and 5 kHz for 30 h/day at daily sound levels of 50, 100, 150 and 200 dB re 1 microPa (A). Sound levels of 150 and 200 dB were considered "noise". The hearing of all animals was evaluated using an evoked potential test (EPT) of the outer hair cells and brainstem auditory evoked potential (BAEP) tests at 1 and 6 months after the exposure. No significant differences were found in the behavioral responses to low frequency signals between the noise and control groups. The mean hearing threshold determined with the EPT and BAEP tests at low frequencies did not differ significantly between the noise and control groups. From these data, we conclude that acute noise exposure does not cause permanent hearing loss in wild killer whales at exposure levels of 0.5-5 kHz.Q:
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{$match: {"_id": {$in: ['fe1e03e0-94a4-4bdd-98e8-e20dabd089c2', 'fe1e03e0-94a4-4bdd-98e8-e20dabd089c3' ]}} be359ba680
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