The effect of audio–visual expectancies on stereoacuity

2012 ◽  
Vol 25 (0) ◽  
pp. 160
Author(s):  
Marina Zannoli ◽  
Pascal Mamassian
Keyword(s):  
Visual System ◽  
Sound Source ◽  
Binocular Disparity ◽  
Frequency Content ◽  
High Pitch ◽  
Low Frequencies ◽  
High Frequencies ◽  
Depth Difference ◽  
Significant Difference ◽  
Do So

Because of greater attenuation of high frequencies, a distant sound carries more low frequencies. As the distance between the listener and a sound source increases, the sound is therefore perceived as having a lower pitch. In the present study, we investigated whether there pre-exists a relationship between depth, as it is perceived by the visual system, and pitch. To do so, we measured stereoacuity (the smallest detectable depth difference that can be seen from binocular disparity). Two lines were presented sequentially at a different depth. Each line was presented along with a beep that lasted as long as the presentation of the line. The two beeps could either have the same pitch or a different pitch associated with the two depths. When the pitch was different, the high pitch could either be associated with the near (congruent with the hypothesis) or the far (incongruent) line. Five participants were asked to determine which line was nearer and instructed not to pay attention to the sound. Results showed no significant difference between the congruent and incongruent sound conditions. However, sensitivity was much better in the two different-pitch conditions compared to the same-pitch condition. In addition, we found no difference between the same-pitch condition and a control condition in which no sound was presented. To conclude, our results suggest that a difference in pitch can improve stereacuity, independent of the frequency content of the sound.

scholarly journals Is the Frequency Content of the Calls in North American Treefrogs Limited by Their Larynges?

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Marcos Gridi-Papp
Keyword(s):  
Frequency Modulation ◽  
Sound Intensity ◽  
Frequency Content ◽  
Frequency Range ◽  
Low Frequencies ◽  
High Frequencies ◽  
Mating Calls ◽  
Limited Frequency ◽  
Positive Direct ◽  
High Diversity

A high diversity of mating calls is found among frogs. The calls of most species, however, are simple, in comparison to those of mammals and birds. In order to determine if the mechanics of the larynx could explain the simplicity of treefrog calls, the larynges of euthanized males were activated with airflow. Laryngeal airflow, sound frequency, and sound intensity showed a positive direct relationship with the driving air pressure. While the natural calls of the studied species exhibit minimal frequency modulation, their larynges produced about an octave of frequency modulation in response to varying pulmonary pressure. Natural advertisement calls are produced near the higher extreme of frequency obtained in the laboratory and at a slightly higher intensity (6 dB). Natural calls also exhibit fewer harmonics than artificial ones, because the larynges were activated with the mouth of the animal open. The results revealed that treefrog larynges allow them to produce calls spanning a much greater range of frequencies than observed in nature; therefore, the simplicity of the calls is not due to a limited frequency range of laryngeal output. Low frequencies are produced at low intensities, however, and this could explain why treefrogs concentrate their calling at the high frequencies.

Measurement of seismic attenuation from high‐resolution crosshole data

Geophysics ◽  
1996 ◽  
Vol 61 (4) ◽  
pp. 1175-1188 ◽  
Author(s):  
J. P. Neep ◽  
M. S. Sams ◽  
M. H. Worthington ◽  
K. A. O’Hara‐Dhand
Keyword(s):  
High Resolution ◽  
Velocity Structure ◽  
Spectral Ratio ◽  
Test Site ◽  
Compressional Wave ◽  
Seismic Attenuation ◽  
Frequency Content ◽  
Low Frequencies ◽  
Significant Difference ◽  
Q Values

High‐resolution crosshole seismic data have been acquired at the Imperial College borehole test site in Northumberland, England. Raypaths between source and receiver were horizontal and parallel to plane layered beds of sandstone, mudstone, and limestone. Shots were fired at 25 cm intervals between the depths of 50 and 72 m. Estimates of the total attenuation using the spectral ratio and centroid frequency shift methods show Q values that correlate well with the frequency content of the first arrivals. Synthetic modeling studies with and without intrinsic attenuation show that the contribution of scattering attenuation is significant and must be accounted for to recover the intrinsic Q values used in the modeling. At some depths, there appears to be an increase in the frequency content of the compressional wave with distance, implying a negative scattering Q. Snapshots of the wave as it travels across the velocity structure at this depth show that the high frequencies are preserved in the wavefield and the low frequencies are scattered to other depths. Intrinsic Q values of less than 20 were obtained at all depths. Within experimental error, there is no evidence to suggest any significant variation of attenuation with lithology. This is consistent with estimates of attenuation from core samples. However, there is a significant difference in the median of Q estimates from the crosshole and core data.

scholarly journals Rapid Lipid Content Screening in Neochloris oleoabundans Utilizing Carbon-Based Dielectrophoresis

Micromachines ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1023
Author(s):  
Cynthia Galicia-Medina ◽  
Matías Vázquez-Piñón ◽  
Gibran Alemán-Nava ◽  
Roberto Gallo-Villanueva ◽  
Sergio Martínez-Chapa ◽  
...  
Keyword(s):  
Glassy Carbon ◽  
Lipid Content ◽  
Low Cost ◽  
Lipid Production ◽  
Neochloris Oleoabundans ◽  
Element Analysis ◽  
Low Frequencies ◽  
High Frequencies ◽  
Significant Difference ◽  
Pdms Microchannel

In this study, we carried out a heterogeneous cytoplasmic lipid content screening of Neochloris oleoabundans microalgae by dielectrophoresis (DEP), using castellated glassy carbon microelectrodes in a PDMS microchannel. For this purpose, microalgae were cultured in nitrogen-replete (N+) and nitrogen-deplete (N−) suspensions to promote low and high cytoplasmic lipid production in cells, respectively. Experiments were carried out over a wide frequency window (100 kHz–30 MHz) at a fixed amplitude of 7 VPP. The results showed a statistically significant difference between the dielectrophoretic behavior of N+ and N− cells at low frequencies (100–800 kHz), whereas a weak response was observed for mid- and high frequencies (1–30 MHz). Additionally, a finite element analysis using a 3D model was conducted to determine the dielectrophoretic trapping zones across the electrode gaps. These results suggest that low-cost glassy carbon is a reliable material for microalgae classification—between low and high cytoplasmic lipid content—through DEP, providing a fast and straightforward mechanism.

scholarly journals A Sound Source Identification Algorithm Based on Bayesian Compressive Sensing and Equivalent Source Method

Sensors ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 865 ◽  
Author(s):  
Ming Zan ◽  
Zhongming Xu ◽  
Linsen Huang ◽  
Zhifei Zhang
Keyword(s):  
Sound Source ◽  
Identification Algorithm ◽  
Reconstruction Accuracy ◽  
Acoustic Holography ◽  
Sound Sources ◽  
Low Frequencies ◽  
High Frequencies ◽  
Equivalent Source ◽  
Sound Source Identification ◽  
Coherent Sources

Near-field acoustic holography (NAH) based on equivalent source method (ESM) is an effective method for identifying sound sources. Conventional ESM focuses on relatively low frequencies and cannot provide a satisfactory solution at high frequencies. So its improved method called wideband acoustic holography (WBH) has been proposed, which has high reconstruction accuracy at medium-to-high frequencies. However, it is less accurate for coherent sound sources at low frequencies. To improve the reconstruction accuracy of conventional ESM and WBH, a sound source identification algorithm based on Bayesian compressive sensing (BCS) and ESM is proposed. This method uses a hierarchical Laplace sparse prior probability distribution, and adaptively adjusts the regularization parameter, so that the energy is concentrated near the correct equivalent source. Referring to the function beamforming idea, the original algorithm with order v can improve its dynamic range, and then more accurate position information is obtained. Based on the simulation of irregular microphone array, comparisons with conventional ESM and WBH show that the proposed method is more accurate, suitable for a wider range of frequencies, and has better reconstruction performance for coherent sources. By increasing the order v, the coherent sources can be located accurately. Finally, the stability and reliability of the proposed method are verified by experiments.

Squirt-flow seismic dispersion models: a comparison

2020 ◽  
Vol 222 (3) ◽  
pp. 2068-2082 ◽  
Author(s):  
Yongyang Sun ◽  
José M Carcione ◽  
Boris Gurevich
Keyword(s):  
Aspect Ratio ◽  
Pore Space ◽  
Crack Density ◽  
Fluid Pressure ◽  
Porous Rocks ◽  
Dispersion Models ◽  
Pore Characteristics ◽  
Low Frequencies ◽  
High Frequencies ◽  
Significant Difference

SUMMARY The anelastic properties of porous rocks depend on the pore characteristics, specifically, the pore aspect ratio and the pore fraction (related to the soft porosity). At high frequencies, there is no fluid pressure communication throughout the pore space and the rock becomes stiffer than at low frequencies, where the pore pressure is fully equilibrated. This causes a significant difference between the moduli at low and high frequencies, which is known as seismic dispersion and is commonly explained by the squirt-flow mechanism. In this paper, we consider and contrast three squirt-flow dispersion models: the modified Mavko–Jizba model, valid for a porous medium with arbitrary shapes of the pores and cracks, and two other models, based on idealized geometries of spheres and ellipsoids: the EIAS (equivalent inclusion-average stress) and CPEM (cracks and pores effective medium) models. We first perform analytical comparisons and then compute several numerical examples to demonstrate similarities and differences between the models. The analytical comparison shows that when the stiff pores are spherical and the crack density is small, the theoretical predictions of the three models are very close to each other. However, when the stiff pores are spheroids with an aspect ratio smaller than 1 (say, between 0.2 and 1), the predictions of inclusion based models are not valid at frequencies of ultrasonic measurements on rock samples. In contrast, the predictions of the modified Mavko–Jizba model are valid at ultrasonic frequencies of about 106 Hz, which is a typical frequency of laboratory measurements on core samples. We also introduce Zener-based bulk and shear dispersion indices, which are proportional to the difference between the high- and low-frequency stiffness moduli, and are a measure of the degree of anelasticity, closely related to the quality factors by view of the Kramers–Kronig relations. The results show that the three models yield similar moduli dispersion with very small differences when the crack density is relatively high. The indices versus crack density can be viewed as a template to obtain the crack properties from low- and high-frequency velocity measurements.

Effect of Blowing Agent on Cell Morphology and Acoustic Absorption of Natural Rubber Foam

2015 ◽  
Vol 804 ◽  
pp. 25-29 ◽  
Author(s):  
Wanlop Harnnarongchai ◽  
Kantima Chaochanchaikul
Keyword(s):  
Natural Rubber ◽  
Cell Size ◽  
Cell Morphology ◽  
Foam Cell ◽  
Adsorption Coefficient ◽  
Low Frequencies ◽  
Potassium Oleate ◽  
High Frequencies ◽  
Blowing Agent ◽  
Open Cell Foam

The sound absorbing efficiency of natural rubber (NR) foam is affected by the cell morphology of foam. Potassium oleate (K-oleate) and sodium bicarbonate (NaHCO3) were used as blowing agents to create open-cell foam. Amounts of the blowing agent were varied from 0.5 to 8.0 part per hundred of rubber (phr) to evaluate cell size and number of foam cell as well as sound adsorption coefficient of NR foam. The NR foam specimens were prepared using mould and air-circulating oven for vulcanizing and foaming processes. The results indicated that K-oleate at 2.0 phr and NaHCO3 at 0.5 phr led to form NR foam with the smallest cell size and the largest number of foam cell. At low frequencies, the optimum sound adsorption coefficient of NR foam was caused by filling K-oleate 2 phr. However, that of NR foam at high frequencies was provided by 0.5 phr-NaHCO3 addition.

Hearing loss in diabetics

1993 ◽  
Vol 107 (3) ◽  
pp. 179-182 ◽  
Author(s):  
J. R. Cullen ◽  
M. J. Cinnamond
Keyword(s):  
Hearing Loss ◽  
Sensorineural Deafness ◽  
Insulin Dosage ◽  
Speech Discrimination ◽  
Low Frequencies ◽  
High Frequencies ◽  
History Of ◽  
Insulin Dependent ◽  
Stapedial Reflex ◽  
The Relationship

The relationship between diabetes and senbsorineural hearing loss has been disputed. This study compares 44 insulin-dependent diabetics with 38 age and sex matched controls. All had pure tone and speech audiometry performed, with any diabetics showing sensorineural deafness undergoing stapedial reflecx decat tests. In 14 diabetics stapedial reflex tests showed no tone decay in any patient, but seven showed evidence of recruitment. Analysis of vaiance showed the diabetics to be significantly deafer than the control population.The hearing loss affected high frequencies in both sexes, but also low frequencies in the male. Speech discrimination scores showed no differences. Further analysis by sex showed the males to account for most of the differences. Analysys of the audiograms showered mostly a high tone loss. Finally duration of disbetes, insulin dosage and family history of diabtes were not found to have a significant effect on threshold.

Seismic analysis of a system of dam-massed foundation-reservoir under inclined excitation

2021 ◽  
pp. 107754632110005
Author(s):  
Payam Sotoudeh ◽  
Mohsen Ghaemian
Keyword(s):  
Seismic Analysis ◽  
Engineering Practice ◽  
Frequency Content ◽  
Earthquake Excitation ◽  
Concrete Dam ◽  
High Frequencies ◽  
Inhomogeneous Waves ◽  
Earthquake Frequency ◽  
Vertical Propagation ◽  
Massed Foundation

One of the acceptable assumptions in engineering practice is vertical propagation of earthquake waves. When the source of earthquake is located very deep in the ground, this assumption is valid, but for sources located in shallow ground, it loses its viability. In this study, linear seismic analysis of a system of concrete dam-massed foundation-reservoir is performed under inclined earthquake excitation. Both P- and SV-type earthquakes are considered for the purpose of the seismic analysis. To consider the effects of inhomogeneous waves for the case of SV wave propagation, post-critical angles are also considered in the analysis. To investigate the effects of earthquake frequency content on the results, three different records with contents of low, intermediate, and high frequencies are selected. Results indicate that considering vertical propagation underestimates the obtained responses. For the case of SV-type earthquakes, post-critical angles must be looked at. Frequency content of the earthquake also has considerable effects on trend and absolute values of responses.

Use of Measured Mobility to Improve SEA Predictions in the Mid-Frequency Range

1999 ◽  
Author(s):  
Jerome E. Manning
Keyword(s):  
Dynamic Systems ◽  
Broad Band ◽  
Measured Data ◽  
Hybrid Technique ◽  
Complex Dynamic ◽  
Low Frequencies ◽  
Large Variability ◽  
High Frequencies ◽  
Complex Dynamic Systems ◽  
Light Coupling

Abstract Statistical energy analysis provides a technique to predict acoustic and vibration levels in complex dynamic systems. The technique is most useful for broad-band excitation at high frequencies where many modes contribute to the response in any given frequency band. At mid and low frequencies, the number of modes contributing to the response may be quite small. In this case SEA predictions show large variability from measured data and may not be useful for vibroacoustic design. This paper focuses on the use of measured data to improve the accuracy of the predictions. Past work to measure the SEA coupling and damping loss factors has not been successful for a broad range of systems that do not have light coupling. This paper introduces a new hybrid SEA technique that combines measured mobility functions with analytical SEA predictions. The accuracy of the hybrid technique is shown to be greatly improved at mid and low frequencies.

Frequency-Weighted Variable-Length Controllers Using Anytime Control Strategies

2011 ◽  
Author(s):  
Gundula B. Runge ◽  
Al Ferri ◽  
Bonnie Ferri
Keyword(s):  
Time Scale ◽  
Weighting Function ◽  
Control Strategies ◽  
Low Frequency ◽  
Low Frequencies ◽  
High Frequencies ◽  
Frequency Components ◽  
Computational Resources ◽  
Weighted Variable ◽  
Selection Of

This paper considers an anytime strategy to implement controllers that react to changing computational resources. The anytime controllers developed in this paper are suitable for cases when the time scale of switching is in the order of the task execution time, that is, on the time scale found commonly with sporadically missed deadlines. This paper extends the prior work by developing frequency-weighted anytime controllers. The selection of the weighting function is driven by the expectation of the situations that would require anytime operation. For example, if the anytime operation is due to occasional and isolated missed deadlines, then the weighting on high frequencies should be larger than that for low frequencies. Low frequency components will have a smaller change over one sample time, so failing to update these components for one sample period will have less effect than with the high frequency components. An example will be included that applies the anytime control strategy to a model of a DC motor with deadzone and saturation nonlinearities.

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