Does anthropogenic noise promotes advertisement call adjustments in the rubí poison frog Andinobates bombetes?

Behaviour ◽  
2021 ◽  
pp. 1-19
Author(s):  
Gina Marcela Jiménez-Vargas ◽  
Fernando Vargas-Salinas
Keyword(s):  
Acoustic Communication ◽  
Emission Rate ◽  
Signal To Noise Ratio ◽  
Anthropogenic Noise ◽  
Advertisement Call ◽  
Playback Experiments ◽  
Signal To Noise ◽  
Low Frequencies ◽  
Poison Frog ◽  
Behavioural Strategy

Abstract Anthropogenic noise, characterized by higher intensities at low frequencies, can restrict acoustic communication between conspecifics and eventually reduce the fitness of populations. We analysed changes in the call features of 52 males of the poison frog A. bombetes subjected to anthropogenic noise through playback experiments. Thirty-one males did not call during playbacks, but the remaining 21 males did. Fourteen of those 21 males increased their dominant call frequency on average 130.76 Hz when exposed to noise. Males did not increase or diminish the emission rate, number of pulses, and duration of their calls. It is possible that males by increasing the frequency of their calls are showing a behavioural strategy that maintain signal-to-noise ratio, which allows them to communicate acoustically in noisy habitats. Further studies are necessary to corroborate this hypothesis given that the magnitude of the increase in call frequency was small (<100 Hz) for most males.

Power spectral analysis of the diaphragm electromyogram

1983 ◽  
Vol 54 (6) ◽  
pp. 1579-1584 ◽  
Author(s):  
T. K. Aldrich ◽  
J. M. Adams ◽  
N. S. Arora ◽  
D. F. Rochester
Keyword(s):  
Power Spectrum ◽  
Signal To Noise Ratio ◽  
Normal Subjects ◽  
Chronic Obstructive ◽  
Signal To Noise ◽  
Low Frequencies ◽  
Mean Values ◽  
The Mean ◽  
Noise Ratio ◽  
Diaphragm Fatigue

We studied the power spectrum of the diaphragm electromyogram (EMG) at frequencies between 31 and 246 Hz in four young normal subjects and five patients with chronic obstructive lung disease (COPD). Diaphragm EMGs were analyzed during spontaneous breathing and maximum inspiratory efforts to determine the effect of signal-to-noise ratio on the power spectrum and if treadmill exercise to dyspnea was associated with diaphragm fatigue. We found that the centroid frequencies of the power spectra (fc) were strongly correlated (r = 0.93) with ratios of power at high frequencies to power at low frequencies (H/L) for all subjects. Of the two indices, H/L had the largest standard deviation expressed as a percentage of the mean. The mean values of both of these decreased significantly after exercise, fc from 100.2 to 97.3 and H/L from 1.07 to 0.97. Signal-to-noise ratios were higher in maximal inspiratory efforts and after exercise in normal subjects and higher in COPD patients. The signal-to-noise ratio was correlated negatively with fc and H/L, indicating that these indices of the shape of the power spectrum are influenced by signal strength and noise levels as well as muscle function. We conclude that the fc and H/L index similar qualities of the power spectrum, that they are partially determined by the signal-to-noise ratio, and that, in some cases, exercise to dyspnea is associated with apparently mild diaphragm fatigue.

SOME TECHNICAL ASPECTS OF REFLECTION SEISMIC PROSPECTING IN THE SAHARA

Geophysics ◽  
1958 ◽  
Vol 23 (3) ◽  
pp. 557-573 ◽  
Author(s):  
M. Pieuchot ◽  
H. Richard
Keyword(s):  
Seismic Reflection ◽  
Signal To Noise Ratio ◽  
Small Signal ◽  
Signal To Noise ◽  
Low Frequencies ◽  
Technical Aspects ◽  
Reflection Seismic ◽  
Linear Dimensions ◽  
Single Trace ◽  
Selection Of

The small signal‐to‐noise ratio encountered in the Sahara required the development of special techniques. The gentle dips and low frequencies permitted the use of a pattern of 100 shot holes recorded by an array of 100 or more geophones per trace with the linear dimensions of the arrays of the order of 100 m. The large structural dimensions allowed the compositing of as many as 5 records into a single trace. Seismic reflection exploration was made economically feasible by the use of pneumatic hammers for drilling and the less expensive nitrates for explosives. The experimental procedures leading to the selection of the techniques are described.

Magnetoelectric Sensors With Directly Integrated Charge Sensitive Readout Circuit—Improved Field Sensitivity and Signal-to-Noise Ratio

2011 ◽  
Vol 11 (10) ◽  
pp. 2260-2265 ◽  
Author(s):  
Zhao Fang ◽  
Ninad Mokhariwale ◽  
Feng Li ◽  
Suman Datta ◽  
Q. M. Zhang
Keyword(s):  
Room Temperature ◽  
Signal To Noise Ratio ◽  
Low Noise ◽  
Magnetic Sensors ◽  
Readout Circuit ◽  
Signal To Noise ◽  
Low Frequencies ◽  
Field Sensitivity ◽  
Piezoelectric Layers ◽  
Noise Ratio

The large magnetoelectric (ME) coupling in the ME laminates makes them attractive for ultrasensitive room temperature magnetic sensors. Here ,we investigate the field sensitivity and signal-to-noise ratio (SNR) of ME laminates, consisting of magnetostrictive and piezoelectric layers (Metglas and piezopolymer PVDF were used as the model system), which are directly integrated with a low noise readout circuit. Both the theoretical analysis and experimental results show that increasing the number of piezoelectric layers can improve the SNR, especially at low frequencies. We also introduce a figure of merit to measure the overall influence of the piezolayer properties on the SNR and show that the newly developed piezoelectric single crystals of PMN-PT and PZN-PT have the promise to achieve a very high SNR and consequently ultra-high sensitivity room temperature magnetic sensors. The results show that the ME coefficients used in early ME composites development works may not be relevant to the SNR. The results also show that enhancing the magnetostrictive coefficient, for example, by employing the flux concentration effect, can lead to enhanced SNR.

scholarly journals A Temporal Model of Aural Frequency Discrimination

2021 ◽  
Author(s):  
◽  
Kaye McAulay
Keyword(s):  
Signal To Noise Ratio ◽  
Discrimination Performance ◽  
Frequency Discrimination ◽  
Signal To Noise ◽  
Low Frequencies ◽  
Human Data ◽  
Temporal Intervals ◽  
Temporal Model ◽  
Noise Ratio ◽  
Positive Axis

<p>The importance of temporal information versus place information in frequency analysis by the ear is a continuing controversy. This dissertation developes a temporal model which simulates human frequency discrimination. The model gives guantitative measures of performance for the discrimination of sinusoids in white gaussian noise. The model simulates human frequency discrimination performance as a function of frequency and signal-to-noise ratio. The model's predictions are based on the temporal intervals between the positive axis crossings of the stimulus. The histograms of these temporal intervals were used as the underlying distributions from which indices of discriminability were calculated. Human freguency discrimination data was obtained for five observers as a function of frequency and signal-to-noise ratio. The data were analysed using the method of Group-operating-characteristic (GOC) Analysis. This method of analysis statistically removes unique noise from data. The unique noise was removed by summing observers' ratings for identical stimuli. This method of analysis gave human frequency discrimination data with less unigue noise than any existing frequency data. The human data were used for evaluating the model. The GOC Analysis was also used to study the improvement in d' as a function of stimulus replications and signal-to-noise ratio. The model was a good fit to the human data at 250 Hz, for two signal-to-noise ratios. The model did not fit the data at 1000 Hz or 5000 Hz. There was some evidence of a transition occuring at 1000 Hz. This investigation supported the idea that human frequency discrimination relies on a temporal mechanism at low frequencies with a transition to some other mechanism at about lO00 Hz.</p>

Low Frequency NQR using Double Contact Cross-relaxation

2000 ◽  
Vol 55 (1-2) ◽  
pp. 37-40
Author(s):  
David Stephenson ◽  
John A. S. Smith
Keyword(s):  
Ammonium Sulphate ◽  
Signal To Noise Ratio ◽  
Low Frequency ◽  
Cross Relaxation ◽  
Relaxation Technique ◽  
Signal To Noise ◽  
Low Frequencies ◽  
Line Shapes ◽  
Ammonium Dichromate ◽  
Noise Ratio

A cross-relaxation technique is described which involves two spin contacts per double reso-nance cycle. The result is an improvement in signal to noise ratio particularly at low frequencies. Experimental spectra and analyses are presented: 14N in ammonium sulphate showing that the tech-nique gives essentially the same information as previous studies; 14N in ammonium dichromate determining e2Qq/h as (76±3) kHz and η = 0.84±.04; 7Li in lithium acetylacetonate for which the spectrum (corrected for Zeeman distortion) yields e2Qq/h = (152 ±5) kHz and η=.5 ±.2. Calculated spectra are presented to demonstrate the η dependence of the line shapes for 7Li.

Quantitative Spectral Evaluation of Shimmer and Jitter

1985 ◽  
Vol 28 (2) ◽  
pp. 169-174 ◽  
Author(s):  
Fritz Klingholz ◽  
Frank Martin
Keyword(s):  
Vocal Fold ◽  
Signal To Noise Ratio ◽  
Voice Disorders ◽  
Voice Disorder ◽  
Wave Spectra ◽  
Noise Levels ◽  
Signal To Noise ◽  
Low Frequencies ◽  
Synthesized Speech ◽  
Spectral Evaluation

A vowel [a]-like, synthesized speech wave was perturbated by defined and comparable jitter and shimmer levels. The signal-to-noise ratio was calculated from the speech wave spectra. Noise emerges in those spectral regions in which the harmonics have high amplitudes, that is, at low frequencies and in the formant regions. Jitter created noise levels significantly higher than shimmer. To verify the theoretical findings, the voices of 32 women with functional voice disorders were analyzed for shimmer and jitter. It was found that only jitter is relevant for differentiating between hypo- and hyperfunctional voice disorders. Jitter was reduced in hyperfunctional voice disorder. This is presumed to be an effect of the high vocal fold tension found in the disorder.

scholarly journals A Temporal Model of Aural Frequency Discrimination

2021 ◽  
Author(s):  
◽  
Kaye McAulay
Keyword(s):  
Signal To Noise Ratio ◽  
Discrimination Performance ◽  
Frequency Discrimination ◽  
Signal To Noise ◽  
Low Frequencies ◽  
Human Data ◽  
Temporal Intervals ◽  
Temporal Model ◽  
Noise Ratio ◽  
Positive Axis

<p>The importance of temporal information versus place information in frequency analysis by the ear is a continuing controversy. This dissertation developes a temporal model which simulates human frequency discrimination. The model gives guantitative measures of performance for the discrimination of sinusoids in white gaussian noise. The model simulates human frequency discrimination performance as a function of frequency and signal-to-noise ratio. The model's predictions are based on the temporal intervals between the positive axis crossings of the stimulus. The histograms of these temporal intervals were used as the underlying distributions from which indices of discriminability were calculated. Human freguency discrimination data was obtained for five observers as a function of frequency and signal-to-noise ratio. The data were analysed using the method of Group-operating-characteristic (GOC) Analysis. This method of analysis statistically removes unique noise from data. The unique noise was removed by summing observers' ratings for identical stimuli. This method of analysis gave human frequency discrimination data with less unigue noise than any existing frequency data. The human data were used for evaluating the model. The GOC Analysis was also used to study the improvement in d' as a function of stimulus replications and signal-to-noise ratio. The model was a good fit to the human data at 250 Hz, for two signal-to-noise ratios. The model did not fit the data at 1000 Hz or 5000 Hz. There was some evidence of a transition occuring at 1000 Hz. This investigation supported the idea that human frequency discrimination relies on a temporal mechanism at low frequencies with a transition to some other mechanism at about lO00 Hz.</p>

scholarly journals Binaural Speech Intelligibility and Interaural Cross-Correlation Under Disturbing Noise and Reverberation

2012 ◽  
Vol 10 (3) ◽  
Author(s):  
A. L. Padilla-Ortíz ◽  
F. Orduña‐Bustamante
Keyword(s):  
Acoustic Communication ◽  
Speech Intelligibility ◽  
Communication Systems ◽  
Cross Correlation ◽  
Signal To Noise Ratio ◽  
Signal To Noise ◽  
Practical Applications ◽  
Subjective Tests ◽  
Noise Ratio

Subjective tests were carried out in order to investigate speech intelligibility, and the possible relative improvements that can be obtained in practical applications to acoustic communication systems, for different forms of presentation through headphones: monaural, monophonic, binaural at 0º (in front of the listener) and binaural at ±30º (right or left, relative to the listener), played back undisturbed, and also with the addition of extreme levels of disturbing noise and reverberation, with a signal to noise ratio of

NQR Studies of Atomic Arrangements and Chemical Bonding in Glasses

1990 ◽  
Vol 45 (3-4) ◽  
pp. 268-272 ◽  
Author(s):  
Donghoon Lee ◽  
S. J. Gravina ◽  
P. J. Bray
Keyword(s):  
Chemical Bonding ◽  
Continuous Wave ◽  
Signal To Noise Ratio ◽  
High Sensitivity ◽  
Signal To Noise ◽  
Low Frequencies ◽  
Large N ◽  
Noise Ratio ◽  
Very High

Abstract A very high sensitivity continuous wave NQR spectrometer was developed to detect pure NQR transitions at low frequencies (down to 200 kHz). A signal-to-noise ratio of more than 100 to 1 has been achieved at about 1.36 MHz for crystalline B 2 0 3 . Two large n B responses have been found in vitreous B 2 0 3 (NMR detected only one site) with linewidths of less than 30 kHz. 27 A1 NQR spectra were obtained for OC-A1203 (Corundum), the mineral andalusite (a form of A1203 • Si0 2), and a glass having the composition of anorthite (CaO • A1203 • 2Si0 2).

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