Changes in masked thresholds of a harbour seal (Phoca vitulina) associated with angular separation of signal and noise sources

1994 ◽  
Vol 72 (11) ◽  
pp. 1863-1866 ◽  
Author(s):  
S. D. Turnbull
Keyword(s):  
White Noise ◽  
Pure Tone ◽  
Noise Source ◽  
Angular Separation ◽  
Phoca Vitulina ◽  
Harbour Seal ◽  
Noise Sources ◽  
Detection Thresholds ◽  
Noise Masker ◽  
Significant Difference

The masked pure tone thresholds of a harbour seal (Phoca vitulina) were measured at various angles using a white noise masker. The white noise source was placed at 0°, 30°, 60°, and 90° relative to the midline of the seal's head (0°). The masked pure tone thresholds for each angle were determined at 2, 4, 8, and 16 kHz. As the angle separating the signal and noise sources increased from 0° to 90°, the critical ratios of the harbour seal decreased by 1–4 dB. This shift in masked thresholds from a reference point of 0° azimuth was significant (H = 10.374, df = 3,16, p < 0.05). No significant difference was found in masked thresholds between 0° and 30° or between 60° and 90°. This indicates that if a noise source is separated by more than 30° relative to the location of a vocalizing seal, signal detection thresholds will be enhanced and communication distances increased.

Masked and unmasked pure tone detection thresholds of a harbour seal listening in air

1991 ◽  
Vol 69 (8) ◽  
pp. 2059-2066 ◽  
Author(s):  
J. M. Terhune
Keyword(s):  
White Noise ◽  
Pure Tone ◽  
Phoca Vitulina ◽  
Harbour Seal ◽  
Optimal Conditions ◽  
Vascular Changes ◽  
Detection Thresholds ◽  
Noise Masker ◽  
Auditory Systems ◽  
Tone Detection

In-air pure tone detection thresholds of a harbour seal (Phoca vitulina) were measured using behavioural psychophysical techniques. Thresholds dropped from about 70 dB re 20 μPa at 0.1 kHz to about 35 dB re 20 μ Pa at 4 kHz and then increased to about 45 dB re 20 μPa at 16 kHz. Increased sensitivities at 2 and 8 kHz, which have been reported in other pinnipeds, were not evident. In-air intensity detection thresholds averaged 32 dB above their underwater counterparts (1–16 kHz). Masking studies found the critical ratios at 0.25, 0.5, and 1 kHz to be 24, 15, and 21 dB, respectively (white noise masker). From 0.2 to 1.5 kHz, bandwidths 20 dB below the level of pure tone maskers were 0.16–0.18 kHz. Circumstantial evidence suggests the possibility that blood vascular changes associated with diving might also influence the sensitivity of the auditory systems of seals. Under optimal conditions, a pup's airborne cries may be detected by its mother at ranges of 1 km or more.

Repetition enhances hearing detection thresholds in a harbour seal (Phoca vitulina)

1993 ◽  
Vol 71 (5) ◽  
pp. 926-932 ◽  
Author(s):  
S. D. Turnbull ◽  
J. M. Terhune
Keyword(s):  
White Noise ◽  
Background Noise ◽  
Phoca Vitulina ◽  
Harbour Seal ◽  
Detection Thresholds ◽  
Noise Masking ◽  
Phoca Groenlandica ◽  
Hearing Thresholds ◽  
Lower Detection ◽  
Pinniped Species

Pure-tone hearing thresholds of a harbour seal (Phoca vitulina) were measured in air and underwater using behavioural psychophysical techniques. A 50-ms sinusoidal pulse was presented in both white-noise masked and unmasked situations at pulse repetition rates of 1, 2, 4, and 10/s. Test frequencies were 0.5, 1.0, 2.0, 4.0, and 8.0 kHz in air and 2.0, 4.0, 8.0, and 16.0 kHz underwater. Relative to 1 pulse/s, mean threshold shifts were −1, −3, and −5 dB at 2, 4, and 10 pulses/s, respectively. The threshold shifts from 1 to 10 pulses/s were significant (F = 12.457, df = 2,36, p < 0.001) and there was no difference in the threshold shifts between the masked and unmasked situations (F = 2.585; df = 1,50; p > 0.10). Broadband masking caused by meteorological or industrial sources will closely resemble the white-noise situation. At high calling rates, the numerous overlapping calls of some species (e.g., harp seal, Phoca groenlandica) present virtually continous "background noise" which also resembles the broadband white-noise masking situation. An implication of lower detection thresholds is that if a seal regularly repeats short vocalizations, the communication range of that call could be increased significantly (80% at 10 pulses/s). This could have important implications during the breeding season should storms or shipping noises occur or when some pinniped species become increasingly vocal and the background noise of conspecifics increases.

Detection thresholds of a harbour seal to repeated underwater high-frequency, short-duration sinusoidal pulses

1988 ◽  
Vol 66 (7) ◽  
pp. 1578-1582 ◽  
Author(s):  
J. M. Terhune
Keyword(s):  
High Frequency ◽  
Threshold Energy ◽  
Phoca Vitulina ◽  
Harbour Seal ◽  
Specific Time ◽  
Detection Thresholds ◽  
Time Period ◽  
Hearing Thresholds ◽  
Number Of Cycles ◽  
Underwater Hearing

Underwater hearing thresholds of a harbour seal (Phoca vitulina) were obtained from 1 to 64 kHz using sinusoidal pulses as short as 0.5 ms. The lowest threshold was 57 dB (re 1 μPa) at 8 kHz. Thresholds for 500- to 50-ms tones increased to about 70 dB (re 1 μPa) in the 1- to 4-kHz and 32-kHz ranges and to 111 dB (re 1 μPa) at 64 kHz. At 50 ms duration, thresholds were from 0 to 6 dB greater than the maximum sensitivity for each frequency tested. Thus, only very brief seal vocalizations are not as audible as longer (and equally loud) underwater calls. For pulses shorter than 400 cycles, the thresholds increased linearly with the logarithm of the number of cycles, independent of frequency (4–32 kHz). The total energy of the pulses at threshold was estimated. From 4 to 32 kHz, as the pulse durations shortened, the threshold energy value decreased and then began to increase. These findings bring into question the concept that when presented with high-frequency sound, the auditory system integrates energy for a specific time period.

White noise and pure tone masking of pure tone thresholds of a harbour seal listening in air and underwater

1990 ◽  
Vol 68 (10) ◽  
pp. 2090-2097 ◽  
Author(s):  
S. D. Turnbull ◽  
J. M. Terhune
Keyword(s):  
White Noise ◽  
Pure Tone ◽  
Broad Band ◽  
Noise Spectrum ◽  
Harbour Seal ◽  
Frequency Resolution ◽  
Pooled Data ◽  
Critical Bandwidth ◽  
Direct Measurements ◽  
Limited Frequency

Background noises mask the detection of sound throughout a limited frequency range termed the critical bandwidth. Critical bandwidths of a harbour seal (Phoca vitulina) were measured, using behavioural psychophysical techniques, by indirect (critical ratios) and direct (two-tone masking) methods underwater and in air. Underwater critical ratios were determined at 4, 8, 16, and 32 kHz, using white noise spectrum levels of 50, 56, 60, and (or) 70 dB re 1 μPa. The critical ratios (pooled data, threshold ±SD) were 19 ± 9, 22 ± 7, 25 ± 7, and 27 ± 5 dB for the respective frequencies. In-air critical ratios were determined at 2, 4, 8, and 16 kHz, using white noise spectrum levels ranging from 23 to 50 dB re 20 μPa. The critical ratios (pooled data) were 25 ± 8, 23 ± 10, 21 ± 15, and 23 ± 16 dB for the respective frequencies. The arithmetic mean of the critical ratios in both media was 23 dB. This suggests that the seal is equally sensitive to pure tone signals in the presence of broad band noise in both air and water. Direct measurements of the critical bandwidth underwater were determined at 4, 8, 16, and 32 kHz, using a pure tone masker ranging from 96 to 120 dB re 1 μPa. In-air direct measurements of the critical bandwidth were measured at 2, 4, and 8 kHz, using a pure tone masker set at 80 dB re 20 μPa. The bandwidths, estimated at 23 dB below the masking level, were all under 2.25 kHz and become proportionately narrow at higher frequencies. These results show a narrow critical bandwidth for the harbour seal, thus indicating high frequency resolution in both media. The directly measured critical bandwidths from the two-tone masking study were not 2.5 times the critical bandwidth estimated from the critical ratios, as previously reported in some other mammals.

Auditory Selective Attention in Cerebral-Palsied Individuals

1985 ◽  
Vol 16 (4) ◽  
pp. 260-266 ◽  
Author(s):  
Lee Ann Laraway
Keyword(s):  
Selective Attention ◽  
White Noise ◽  
Normal Subjects ◽  
Auditory Selective Attention ◽  
Normal Individuals ◽  
Significant Difference

The purpose of this study was to determine whether there is a statistically significant difference between the auditory selective attention abilities of normal and cerebral-palsied individuals. Twenty-three cerebral-palsied and 23 normal subjects between the ages of 5 and 21 were asked to repeat a series of 30 items consisting of from 2 to 4 digits in the presence of intermittent white noise. Results of the study indicate that cerebral-palsied individuals perform significantly poorer than normal individuals when the stimulus is accompanied by noise. Noise was not a significant factor in the performance of the normal subjects regardless of age.

Noise source location and scaling of subsonic upper-surface blowing

2020 ◽  
Vol 19 (3-5) ◽  
pp. 191-206
Author(s):  
Trae L Jennette ◽  
Krish K Ahuja
Keyword(s):  
Strouhal Number ◽  
Noise Source ◽  
Low Frequency ◽  
Directivity Pattern ◽  
Source Location ◽  
Dipole Source ◽  
Frequency Noise ◽  
Noise Sources ◽  
Trailing Edge ◽  
Trailing Edge Noise

This paper deals with the topic of upper surface blowing noise. Using a model-scale rectangular nozzle of an aspect ratio of 10 and a sharp trailing edge, detailed noise contours were acquired with and without a subsonic jet blowing over a flat surface to determine the noise source location as a function of frequency. Additionally, velocity scaling of the upper surface blowing noise was carried out. It was found that the upper surface blowing increases the noise significantly. This is a result of both the trailing edge noise and turbulence downstream of the trailing edge, referred to as wake noise in the paper. It was found that low-frequency noise with a peak Strouhal number of 0.02 originates from the trailing edge whereas the high-frequency noise with the peak in the vicinity of Strouhal number of 0.2 originates near the nozzle exit. Low frequency (low Strouhal number) follows a velocity scaling corresponding to a dipole source where as the high Strouhal numbers as quadrupole sources. The culmination of these two effects is a cardioid-shaped directivity pattern. On the shielded side, the most dominant noise sources were at the trailing edge and in the near wake. The trailing edge mounting geometry also created anomalous acoustic diffraction indicating that not only is the geometry of the edge itself important, but also all geometry near the trailing edge.

scholarly journals Innovative techniques for the improvement of industrial noise sources identification by beamforming

Noise Mapping ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 129-137
Author(s):  
Giorgio Baldinelli ◽  
Francesco Bianchi ◽  
Danilo Costarelli ◽  
Francesco D’Alessandro ◽  
Flavio Scrucca ◽  
...  
Keyword(s):  
Image Processing ◽  
Noise Source ◽  
Focal Length ◽  
Noise Sources ◽  
Geometric Information ◽  
Industrial Noise ◽  
Sources Identification ◽  
Innovative Technique ◽  
Innovative Techniques

Abstract An innovative technique based on beamforming is implemented, at the aim of detecting the distances from the observer and the relative positions among the noise sources themselves in multisource noise scenarios. By means of preliminary activities to assess the optical camera focal length and stereoscopic measurements followed by image processing, the geometric information in the source-microphone direction is retrieved, a parameter generally missed in classic beamforming applications. A corollary of the method consists of the possibility of obtaining also the distance among different noise sources which could be present in a multisource environment. A loss of precision is found when the effect of the high acoustic reflectivity ground interferes with the noise source.

The Effect of Monaurally Fitted Hearing Aid Use on the Evolution of Presbycusis

2021 ◽  
pp. 000348942199527
Author(s):  
Gabriel Dunya ◽  
Fadi Najem ◽  
Aurelie Mailhac ◽  
Samer Abou Rizk ◽  
Marc Bassim
Keyword(s):  
Word Recognition ◽  
Pure Tone ◽  
Hearing Aid ◽  
Residual Hearing ◽  
Inclusion Criteria ◽  
Pure Tone Average ◽  
Hearing Aid Use ◽  
Deprivation Effect ◽  
Significant Difference

Objective: The effect of hearing aid use on the evolution of presbycusis has not been well described in the literature, with only a handful of publications addressing this topic. This paper aims to evaluate the long-term use of amplification and its effect on pure-tone thresholds and word recognition scores. Method: Monaurally fitted patients were followed with serial audiograms. Data was collected from hearing aid centers. Seventy-seven patients with presbycusis met the inclusion criteria and participated in the present study. The progression of hearing loss in both pure tone thresholds and word recognition scores were compared between the hearing aid ears (HA), and the non-hearing aid ears (NHA). Pure tone thresholds were analyzed by comparing the pure tone average at the initial and last audiograms. Word Recognition Scores (WRS) were analyzed using the model of Thornton and Raffin (1978), and by comparing the change in the absolute values of WRS from the initial to the last audiogram between the HA ear and the NHA ear. Results: No significant difference in pure-tone thresholds between the HA ear and NHA ear was found at the last audiogram ( P = .696), even after dividing the patients into groups based on the duration of amplification. Both methods of analysis of patients’ WRS showed a statistically significant worsening in NHA ( P < .05). Conclusion: The present study supports the previously defined auditory deprivation effect on non-fitted ears, which showed worsening of word recognition over time and no effect on pure tone average. It provides an additional argument for the counseling of patients with presbycusis considering amplification, and highlights the importance of bilateral amplification in preserving the residual hearing of hearing impaired patients.

Vitamin A physiology in the precocious harbour seal (Phoca vitulina): a tissue-based biomarker approach

2002 ◽  
Vol 80 (9) ◽  
pp. 1511-1519 ◽  
Author(s):  
Lizzy Mos ◽  
Peter S Ross
Keyword(s):  
Vitamin A ◽  
Marine Mammals ◽  
Relevant Information ◽  
Phoca Vitulina ◽  
Retinyl Palmitate ◽  
Harbour Seal ◽  
Natural Processes ◽  
Reproductive Endocrine ◽  
Positive Correlations ◽  
Free Ranging

Vitamin A is a nutrient essential to all mammals for growth and development, as well as for the maintenance of reproductive, endocrine, and immune systems. Environmental contaminant-related disruption of vitamin A has been observed in many wildlife species and can therefore be used as a biomarker of toxic effects. However, the natural processes regulating vitamin A uptake, storage, and distribution among compartments are poorly understood in marine mammals. In this study, 20 young healthy harbour seals (Phoca vitulina) were captured to establish a compartment-based model providing a foundation for a mechanistic understanding of vitamin A physiology and disruption. Vitamin A (retinol, retinyl palmitate, and (or) retinoic acid) was quantified in blood plasma and in biopsy samples of liver, blubber, and skin. Although the highest concentrations of vitamin A were found in liver, blubber represents a more important storage depot, with an estimated 66% of the total retinoid content of the compartments measured. We suggest that vitamin A physiology in the precocious harbour seal has evolved to deal with high vitamin A availability during a short nursing period and to sustain growth during the postweaning fast. Positive correlations in vitamin A concentrations among liver, blubber, and skin support the use of less invasive biopsy sampling of just blubber or skin, which can provide physiologically relevant information in biomarker studies of free-ranging marine mammals.

scholarly journals The importance of central auditory evaluation in Friedreich's ataxia

2018 ◽  
Vol 76 (3) ◽  
pp. 170-176 ◽  
Author(s):  
Bianca Simone Zeigelboim ◽  
Hélio A. G. Teive ◽  
Michèlli Rodrigues da Rosa ◽  
Jéssica Spricigo Malisky ◽  
Vinicius Ribas Fonseca ◽  
...  
Keyword(s):  
Pure Tone ◽  
Evoked Potential ◽  
Pure Tone Audiometry ◽  
Friedreich’S Ataxia ◽  
Friedreich's Ataxia ◽  
Auditory Evoked Potential ◽  
Acoustic Reflex ◽  
Cross Sectional ◽  
Significant Difference ◽  
Central Auditory Function

ABSTRACT Objective To assess central auditory function in Friedreich's ataxia. Methods A cross-sectional, retrospective study was carried out. Thirty patients underwent the anamnesis, otorhinolaryngology examination, pure tone audiometry, acoustic immittance measures and brainstem auditory evoked potential (BAEP) assessments. Results The observed alterations were: 43.3% in the pure tone audiometry, bilateral in 36.7%; 56.6% in the BAEP test, bilateral in 50%; and 46.6% in the acoustic immittance test. There was a significant difference (p < 0.05) in the comparison between the tests performed. Conclusion In the audiological screening, there was a prevalence of the descending audiometric configuration at the frequency of 4kHz, and absence of the acoustic reflex at the same frequency. In the BAEP test, there was a prevalence of an increase of the latencies in waves I, III and V, and in the intervals of interpeaks I-III, I-V and III-V. In 13.3% of the patients, wave V was absent, and all waves were absent in 3.3% of patients.

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