Audiograms for the dolphins BLU and TYH. The solid lines are cubic spline fits to the threshold values. A representative example of the mean ambient noise pressure spectral density levels is also shown.
Distributions of the difference between the false alarm rates measured during pre-and post-exposure threshold testing. The difference is defined as the post-exposure false alarm rate minus the pre-exposure rate.
The growth of TTS4 at each exposure frequency. Circles, solid lines: BLU; triangles, dashed lines: TYH; C: control sessions. The lines show the best fits of Eq. (1) to the data (see Table II ). The open symbols show the mean TTS4 (±1 SD) from the control sessions. All exposures were 16-s in duration.
(a) “Onset TTS” exposure levels, based on the SPL (left ordinate) and SEL (right ordinate) required to induce a TTS4 of 6 dB. The auditory thresholds, in dB SPL (left ordinate), are also shown for comparison. BLU: solid circles; TYH: open circles. (b) Relative susceptibility values from the present study (symbols) compared to dolphin weighting functions derived from equal loudness contours measured in the dolphin TYH (lines; Finneran and Schlundt, 2011 ).
Recovery from TTS at each exposure frequency. BLU: solid circles; TYH: solid triangles. The recovery data with TTS4 ≥ 6 dB were fit with a modified exponential function ( Patuzzi, 1998 ).
Best-fit values of the recovery function parameters n 1 and n 2 as functions of TTS4 [see Eqs. (2) and (3) ]. The lines are linear fits to the parameter values, with the two smallest values of n 1 and largest values of n 2, which corresponded to the two largest shifts at 28.3 kHz, excluded.
Test frequencies, number of controls and exposures, and exposure SPL range for each subject.
Best-fit parameters for Eq. (1) fit to TTS4 growth data. a,b = fitting parameters, = adjusted coefficient of determination, and n = number of samples.
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