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.

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.

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.

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.

The effect of signal duration on the underwater hearing thresholds of two harbor seals (Phoca vitulina) for single tonal signals between 0.2 and 40 kHz

2010 ◽  
Vol 127 (2) ◽  
pp. 1135-1145 ◽  
Author(s):  
Ronald A. Kastelein ◽  
Lean Hoek ◽  
Paul J. Wensveen ◽  
John M. Terhune ◽  
Christ A. F. de Jong
Keyword(s):  
Phoca Vitulina ◽  
Signal Duration ◽  
Harbor Seals ◽  
Hearing Thresholds ◽  
Underwater Hearing

Hearing Thresholds of Two Harbor Seals (Phoca vitulina) for Helicopter Dipping Sonar Signals (1.3-1.4 kHz)

2019 ◽  
Vol 45 (3) ◽  
pp. 349-355
Author(s):  
Ronald A. Kastelein ◽  
Robin Gransier ◽  
Marloe Brouwers ◽  
Lean Helder-Hoek
Keyword(s):  
Phoca Vitulina ◽  
Harbor Seals ◽  
Hearing Thresholds

A Study on Sun Shading Reconstruction Design of Residential Buildings in Chongqing City

2014 ◽  
Vol 953-954 ◽  
pp. 1481-1487
Author(s):  
Liu Jin
Keyword(s):  
Energy Saving ◽  
Personal Experience ◽  
Design Pattern ◽  
Simulation Analysis ◽  
Residential Buildings ◽  
Residential Building ◽  
Specific Time ◽  
High Rise ◽  
Time Period ◽  
Chongqing City

Windows energy saving design of residential buildings has increasingly got the attention of people. Through a large number of surveys and analysis of residential buildings in Chongqing and consumers personal experience, the author finds problems and deficiency, and then proposes principles of residential buildings sun shading reconstruction in Chongqing city. Taking the high-rise residential building of one university in Chongqing as reconstruction sample, selecting a specific time period, the author recalculates sun shading coefficient with and without sun shading by using Ecotect software to do simulation analysis. Finally, the reasonable reconstruction design pattern is put forward through cases. Keywords: Buildings Sun Shading, Sun Shading Reconstruction, Energy Saving

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 Evaluation of Recreational Noise Exposure and High Frequency Hearing Thresholds of University Students with Normal Hearing Between 125-8,000 Hz

2021 ◽  
Vol 29 (2) ◽  
pp. 119-126
Author(s):  
Banu MÜJDECİ ◽  
Şule KAYA ◽  
Meltem TULĞAR ◽  
Kürşad KARAKOÇ ◽  
Mustafa KARABULUT ◽  
...  
Keyword(s):  
University Students ◽  
High Frequency ◽  
Noise Exposure ◽  
Normal Hearing ◽  
Hearing Thresholds

scholarly journals Traffic Flow Pattern in Road Network Using Clustering

2020 ◽  
Vol 5 (8) ◽  
pp. 229-230
Author(s):  
Ganga Gudi ◽  
Dr. Hanumanthappa M
Keyword(s):  
Traffic Flow ◽  
Global Positioning System ◽  
Road Network ◽  
Location Based Services ◽  
Positioning System ◽  
Specific Time ◽  
Real World Problem ◽  
Time Period ◽  
Global Positioning ◽  
Enormous Amount

Wireless communication has become important in location-based services. The enormous amount of data is extracted for useful information to solve the real world problem. Global positioning system, is used to captures the position of an object at specific time period. The scheme is finding the congested route by considering the number of vehicles in a road segment. It consists of two methods, firstly it finds the group of points based on consistency of route points and second it arranges the groups in sequence of values for each route

scholarly journals Mapping the Canadian landscape : the performing arts and experiential perspectives

2021 ◽  
Author(s):  
Christine Alison Johns
Keyword(s):  
Art History ◽  
Performing Arts ◽  
Ways Of Knowing ◽  
Specific Time ◽  
Performing Artists ◽  
Place And Space ◽  
Specific Time Period ◽  
Time Period ◽  
Performing Art ◽  
The Way

Focusing on a specific time period in Canadian performing art history--from the 1970s through to the late 1990s--this thesis "maps out" three artists' experiences in the landscape and the way these experiences are represented to an audience through performance. Using specific examples from the repertoire of Davida Monk, Paul Thompson, and R. Murray Schafer, I make a case for considering these performing artists as landscape researchers. I suggest that their performances explicitly and implicitly explore foundational questions about the meanings, uses, and affective power of landscape in ways that are analogous to the writings of cultural geographers during the same period. Like Yi-Fu Tuan, John Jakle, Denis Cosgrove and Jay Appleton, these performing artists examine the experience of humans in the landscape and focus on issues of place and space, homeland, and the meaning of landscape. Monk, Thompson and Schafer extend the perspectives of the geographers and bridge important gaps in their ways of knowing landscape.

Sign in / Sign up

Export Citation Format

Share Document